Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to the U.S. Navy Training Activities in the Gulf of Alaska Study Area, 49656-49765 [2022-16509]
Download as PDF
<![CDATA[
49656
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
50 CFR Part 218
[Docket No. 220726–0163]
RIN 0648–BK46
Taking and Importing Marine
Mammals; Taking Marine Mammals
Incidental to the U.S. Navy Training
Activities in the Gulf of Alaska Study
Area
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
ACTION: Proposed rule; request for
comments and information.
AGENCY:
NMFS has received a request
from the U.S. Navy (Navy) to take
marine mammals incidental to training
activities conducted in the Gulf of
Alaska (GOA) Study Area (hereafter
referred to as the GOA Study Area).
Pursuant to the Marine Mammal
Protection Act (MMPA), NMFS is
requesting comments on its proposal to
issue regulations and a subsequent
Letter of Authorization (LOA) to the
Navy to incidentally take marine
mammals during the specified activities.
NMFS will consider public comments
prior to issuing any final rule and
making final decisions on the issuance
of the requested LOA. Agency responses
to public comments will be provided in
the notice of the final decision. The
Navy’s activities qualify as military
readiness activities pursuant to the
MMPA, as amended by the National
Defense Authorization Act for Fiscal
Year 2004 (2004 NDAA).
DATES: Comments and information must
be received no later than September 26,
2022.
ADDRESSES: Submit all electronic public
comments via the Federal e-Rulemaking
Portal. Go to https://
www.regulations.gov and enter NOAA–
NMFS–2022–0060 in the Search box.
Click on the ‘‘Comment’’ icon, complete
the required fields, and enter or attach
your comments.
Instructions: Comments sent by any
other method, to any other address or
individual, or received after the end of
the comment period, may not be
considered by NMFS. All comments
received are a part of the public record
and will generally be posted for public
viewing on www.regulations.gov
without change. All personal identifying
information (e.g., name, address),
confidential business information, or
lotter on DSK11XQN23PROD with PROPOSALS2
SUMMARY:
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
otherwise sensitive information
submitted voluntarily by the sender will
be publicly accessible. NMFS will
accept anonymous comments (enter ‘‘N/
A’’ in the required fields if you wish to
remain anonymous). Attachments to
electronic comments will be accepted in
Microsoft Word, Excel, or Adobe PDF
file formats only.
A copy of the Navy’s application and
other supporting documents and
documents cited herein may be obtained
online at: https://
www.fisheries.noaa.gov/action/
incidental-take-authorization-us-navytraining-activities-gulf-alaskatemporary-maritime-0. In case of
problems accessing these documents,
please use the contact listed here (see
FOR FURTHER INFORMATION CONTACT).
FOR FURTHER INFORMATION CONTACT:
Leah Davis, Office of Protected
Resources, NMFS, (301) 427–8401.
SUPPLEMENTARY INFORMATION:
Purpose of Regulatory Action
These proposed regulations, issued
under the authority of the MMPA (16
U.S.C. 1361 et seq.), would provide the
framework for authorizing the take of
marine mammals incidental to the
Navy’s training activities (which qualify
as military readiness activities),
including the use of sonar and other
transducers, and in-air detonations at or
near the surface (within 10 m above the
water surface) in the GOA Study Area.
The GOA Study Area is comprised of
three areas: the Temporary Maritime
Activities Area (TMAA), a warning area,
and the Western Maneuver Area (WMA)
(see Figure 1). The TMAA and WMA are
temporary areas established within the
GOA for ships, submarines, and aircraft
to conduct training activities. The
warning area overlaps and extends
slightly beyond the northern corner of
the TMAA. The WMA is located south
and west of the TMAA and provides
additional surface, sub-surface, and
airspace in which to maneuver in
support of activities occurring within
the TMAA. The use of sonar and other
transducers, and explosives would not
occur within the WMA.
NMFS received an application from
the Navy requesting 7-year regulations
and an authorization to incidentally
take individuals of multiple species of
marine mammals (‘‘Navy’s rulemaking/
LOA application’’ or ‘‘Navy’s
application’’). Take is anticipated to
occur by Level A harassment and Level
B harassment incidental to the Navy’s
training activities. No lethal take is
anticipated or proposed for
authorization.
PO 00000
Frm 00002
Fmt 4701
Sfmt 4702
Background
The MMPA prohibits the ‘‘take’’ of
marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and
(D) of the MMPA direct the Secretary of
Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but
not intentional, taking of small numbers
of marine mammals by U.S. citizens
who engage in a specified activity (other
than commercial fishing) within a
specified geographical region if certain
findings are made and either regulations
are proposed or, if the taking is limited
to harassment, the public is provided
with notice of the proposed incidental
take authorization and provided the
opportunity to review and submit
comments.
An authorization for incidental
takings shall be granted if NMFS finds
that the taking will have a negligible
impact on the species or stocks and will
not have an unmitigable adverse impact
on the availability of the species or
stocks for taking for subsistence uses
(where relevant). Further, NMFS must
prescribe the permissible methods of
taking and other means of effecting the
least practicable adverse impact on the
affected species or stocks and their
habitat, paying particular attention to
rookeries, mating grounds, and areas of
similar significance, and on the
availability of such species or stocks for
taking for certain subsistence uses
(referred to in this rule as ‘‘mitigation
measures’’); and requirements
pertaining to the monitoring and
reporting of such takings. The MMPA
defines ‘‘take’’ to mean to harass, hunt,
capture, or kill, or attempt to harass,
hunt, capture, or kill any marine
mammal. The Preliminary Analysis and
Negligible Impact Determination section
below discusses the definition of
‘‘negligible impact.’’
The NDAA for Fiscal Year 2004 (2004
NDAA) (Pub. L. 108–136) amended
section 101(a)(5) of the MMPA to
remove the ‘‘small numbers’’ and
‘‘specified geographical region’’
provisions indicated above and
amended the definition of ‘‘harassment’’
as applied to a ‘‘military readiness
activity.’’ The definition of harassment
for military readiness activities (Section
3(18)(B) of the MMPA) is (i) Any act that
injures or has the significant potential to
injure a marine mammal or marine
mammal stock in the wild (Level A
Harassment); or (ii) Any act that
disturbs or is likely to disturb a marine
mammal or marine mammal stock in the
wild by causing disruption of natural
behavioral patterns, including, but not
limited to, migration, surfacing, nursing,
breeding, feeding, or sheltering, to a
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
point where such behavioral patterns
are abandoned or significantly altered
(Level B harassment). In addition, the
2004 NDAA amended the MMPA as it
relates to military readiness activities
such that the least practicable adverse
impact analysis shall include
consideration of personnel safety,
practicality of implementation, and
impact on the effectiveness of the
military readiness activity.
More recently, Section 316 of the
NDAA for Fiscal Year 2019 (2019
NDAA) (Pub. L. 115–232), signed on
August 13, 2018, amended the MMPA to
allow incidental take rules for military
readiness activities under section
101(a)(5)(A) to be issued for up to 7
years. Prior to this amendment, all
incidental take rules under section
101(a)(5)(A) were limited to 5 years.
Summary and Background of Request
On October 9, 2020, NMFS received
an adequate and complete application
from the Navy requesting authorization
for take of marine mammals, by Level A
harassment and Level B harassment,
incidental to training from the use of
active sonar and other transducers and
explosives (in-air, occurring at or above
the water surface) in the TMAA over a
7-year period beginning when the
current authorization expires. On March
12, 2021, the Navy submitted an
updated application that provided
revisions to the Northern fur seal take
estimate and incorporated additional
best available science. In August 2021,
the Navy communicated to NMFS that
it was considering an expansion of the
GOA Study Area and an expansion of
the Portlock Bank Mitigation Area
proposed in its previous applications.
On February 2, 2022, the Navy
submitted a second updated application
that described the addition of the WMA
to the GOA Study Area (which
previously just consisted of the TMAA)
and the replacement of the Portlock
Bank Mitigation Area with the
Continental Shelf and Slope Mitigation
Area. The Navy is not planning to
conduct any testing activities.
On January 8, 2021 (86 FR 1483), we
published a notice of receipt (NOR) of
application in the Federal Register,
requesting comments and information
related to the Navy’s request for 30 days.
We received one comment on the NOR
that was non-substantive in nature.
The following types of training, which
are classified as military readiness
activities pursuant to the MMPA, as
amended by the 2004 NDAA, would be
covered under the regulations and LOA
(if issued): surface warfare (detonations
at or above the water surface) and antisubmarine warfare (sonar and other
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
transducers). The Navy is also
conducting Air Warfare, Electronic
Warfare, Naval Special Warfare, Strike
Warfare, and Support Operations, but
these activities do not involve sonar and
other transducers, detonations at or
above the water surface, or any other
stressors that could result in the take of
marine mammals. (See the 2020 GOA
Draft SEIS/OEIS for more detail on those
activities). The activities would not
include in-water explosives, pile
driving/removal, or use of air guns.
This would be the third time NMFS
has promulgated incidental take
regulations pursuant to the MMPA
relating to similar military readiness
activities in the GOA, following those
effective beginning May 4, 2011 (76 FR
25479; May 4, 2011) and April 26, 2017
(82 FR 19530; April 27, 2017).
The Navy’s mission is to organize,
train, equip, and maintain combat-ready
naval forces capable of winning wars,
deterring aggression, and maintaining
freedom of the seas. This mission is
mandated by Federal law (10 U.S.C.
8062), which requires the readiness of
the naval forces of the United States.
The Navy executes this responsibility by
establishing and executing training
programs, including at-sea training and
exercises, and ensuring naval forces
have access to the ranges, operating
areas (OPAREA), and airspace needed to
develop and maintain skills for
conducting naval activities.
The Navy has conducted training
activities in the TMAA portion of the
GOA Study Area since the 1990s. Since
the 1990s, the Department of Defense
has conducted a major joint training
exercise in Alaska and off the Alaskan
coast that involves the Departments of
the Navy, Army, Air Force, and Coast
Guard participants reporting to a unified
or joint commander who coordinates the
activities. These activities are planned
to demonstrate and evaluate the ability
of the services to engage in a conflict
and successfully carry out plans in
response to a threat to national security.
The Navy’s planned activities for the
period of this proposed rule would be
a continuation of the types and level of
training activities that have been
ongoing for more than a decade. While
the specified activities have not
changed, there are changes in the
platforms and systems used in those
activities, as well as changes in the bins
(source classifications) used to analyze
the activities. (For example, two new
sonar bins were added (MF12 and
ASW1) and another bin was eliminated
(HF6). This was due to changes in
platforms and systems.) Further, the
Navy expanded the GOA Study Area to
include the WMA, though the vast
PO 00000
Frm 00003
Fmt 4701
Sfmt 4702
49657
majority of the training activities would
still occur only in the TMAA.
The Navy’s rulemaking/LOA
application reflects the most up-to-date
compilation of training activities
deemed necessary by senior Navy
leadership to accomplish military
readiness requirements. The types and
numbers of activities included in the
proposed rule account for fluctuations
in training in order to meet evolving or
emergent military readiness
requirements. These proposed
regulations would become effective in
December of 2022 and would cover
training activities that would occur for
a 7-year period following the expiration
of the current MMPA authorization for
the GOA, which expired on April 26,
2022.
Description of the Specified Activity
The Navy requests authorization to
take marine mammals incidental to
conducting training activities. The Navy
has determined that acoustic and
explosives stressors are most likely to
result in impacts on marine mammals
that could rise to the level of
harassment, and NMFS concurs with
this determination. Detailed
descriptions of these activities are
provided in Chapter 2 of the 2020 GOA
Draft Supplemental Environmental
Impact Statement (SEIS)/Overseas EIS
(OEIS) (2020 GOA DSEIS/OEIS) (https://
www.goaeis.com/) and in the Navy’s
rulemaking/LOA application (https://
www.fisheries.noaa.gov/action/
incidental-take-authorization-us-navytraining-activities-gulf-alaskatemporary-maritime-0) and are
summarized here.
Dates and Duration
Training activities would be
conducted intermittently in the GOA
Study Area over a maximum time
period of up to 21 consecutive days
annually from April to October to
support a major joint training exercise
in Alaska and off the Alaskan coast that
involves the Departments of the Navy,
Army, Air Force, and Coast Guard. The
participants report to a unified or joint
commander who coordinates the
activities planned to demonstrate and
evaluate the ability of the services to
engage in a conflict and carry out plans
in response to a threat to national
security. The specified activities would
occur over a maximum time period of
up to 21 consecutive days each year
during the 7-year period of validity of
the regulations. The proposed number
of training activities are described in the
Detailed Description of Proposed
Activities section (Table 3) of this
proposed rule.
E:\FR\FM\11AUP2.SGM
11AUP2
49658
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
Geographical Region
lotter on DSK11XQN23PROD with PROPOSALS2
The GOA Study Area (see Figure 1
below and Figure ES–1 of the 2022
Supplement to the 2020 GOA DSEIS/
OEIS) is entirely at sea and is comprised
of the TMAA and a warning area in the
Gulf of Alaska, and the WMA. The term
‘‘at-sea’’ refers to training activities in
the Study Area (both the TMAA and
WMA) that occur (1) on the ocean
surface, (2) beneath the ocean surface,
and (3) in the air above the ocean
surface. Navy training activities
occurring on or over the land outside
the GOA Study Area are not included in
this proposed rule, and are covered
under separate environmental
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
documentation prepared by the U.S. Air
Force and the U.S. Army. As depicted
in Figure 1 of this proposed rule, the
TMAA is a polygon roughly resembling
a rectangle oriented from northwest to
southeast, approximately 300 nmi (556
km) in length by 150 nmi (278 km) in
width, located south of Montague Island
and east of Kodiak Island. The GOA
Study Area boundary was intentionally
designed to avoid ESA-designated
Steller sea lion critical habitat. The
WMA is located south and west of the
TMAA, and provides an additional
185,806 nmi2 of surface, sub-surface,
and airspace training to support
activities occurring within the TMAA
(Figure 1). The boundary of the WMA
PO 00000
Frm 00004
Fmt 4701
Sfmt 4702
follows the bottom of the slope at the
4,000 m contour line, and was
configured to avoid overlap and impacts
to ESA-designated critical habitat,
biologically important areas (BIAs),
migration routes, and primary fishing
grounds. The WMA provides additional
airspace and sea space for aircraft and
vessels to maneuver during training
activities for increased training
complexity. The TMAA and WMA are
temporary areas established within the
GOA for ships, submarines, and aircraft
to conduct training activities.
Additional detail can be found in
Chapter 2 of the Navy’s rulemaking/
LOA application.
BILLING CODE 3510–22–P
E:\FR\FM\11AUP2.SGM
11AUP2
49659
BILLING CODE 3510–22–C
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00005
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
EP11AU22.000</GPH>
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
49660
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
Primary Mission Areas
The Navy categorizes many of its
training activities into functional
warfare areas called primary mission
areas. The Navy’s planned activities for
the GOA Study Area generally fall into
the following six primary mission areas:
Air Warfare; Surface Warfare; AntiSubmarine Warfare; Electronic Warfare;
Naval Special Warfare; and Strike
Warfare. Most activities conducted in
the GOA are categorized under one of
these primary mission areas; activities
that do not fall within one of these areas
are listed as ‘‘support operations’’ or
‘‘other training activities.’’ Each warfare
community (aviation, surface, and
subsurface) may train in some or all of
these primary mission areas. A
description of the sonar, munitions,
targets, systems, and other materials
used during training activities within
these primary mission areas is provided
in Appendix A (Navy Activities
Descriptions) of the 2020 GOA DSEIS/
OEIS and section ES.2.2 (Proposed
Activities in the Western Maneuver
Area) of the 2022 Supplement to the
2020 GOA DSEIS/OEIS.
The Navy describes and analyzes the
effects of its training activities within
the 2020 GOA DSEIS/OEIS and 2022
Supplement to the 2020 GOA DSEIS/
OEIS. In its assessment, the Navy
concluded that of the activities to be
conducted within the GOA Study Area,
sonar use and in-air explosives
occurring at or above the water surface
were the stressors resulting in impacts
on marine mammals that could rise to
the level of harassment as defined under
the MMPA. (The Navy is not proposing
to conduct any activities that use inwater or underwater explosives.)
Further, these activities are limited to
the TMAA. No activities involving sonar
use or explosives would occur in the
WMA or the portion of the warning area
that extends beyond the TMAA.
Therefore, the Navy’s rulemaking/LOA
application provides the Navy’s
assessment of potential effects from
sonar use and explosives occurring at or
above the water surface in terms of the
various warfare mission areas they are
associated with. Those mission areas
include the following:
• surface warfare (in-air detonations
at or above the water surface); 1 and
• anti-submarine warfare (sonar and
other transducers).
The Navy’s activities in Air Warfare,
Electronic Warfare, Naval Special
Warfare, Strike Warfare, Support
Operations, and Other Training
Activities do not involve sonar and
1 Defined herein as being within 10 meters of the
ocean surface.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
other transducers, detonations at or near
the surface, or any other stressors that
could result in harassment, serious
injury, or mortality of marine mammals.
Therefore, the activities in these warfare
areas are not discussed further in this
proposed rule, but are analyzed fully in
the 2020 GOA DSEIS/OEIS and 2022
Supplement to the 2020 GOA DSEIS/
OEIS. The specific acoustic sources
analyzed in this proposed rule are
contained in the 2020 GOA DSEIS/OEIS
and are presented in the following
sections based on the primary mission
areas.
Surface Warfare
The mission of surface warfare
(named anti-surface warfare in the 2011
GOA Final Environmental Impact
Statement (FEIS)/Overseas
Environmental Impact Statement (OEIS)
and 2016 GOA Final Supplemental
Environmental Impact Statement
(FSEIS)/OEIS, but since changed by the
Navy to ‘‘Surface Warfare’’) is to obtain
control of sea space from which naval
forces may operate, which entails
offensive action against surface targets
while also defending against enemy
forces. In surface warfare, aircraft use
guns, air-launched cruise missiles, or
other precision-guided munitions; ships
employ naval guns and surface-tosurface missiles; and submarines attack
surface ships using anti-ship cruise
missiles.
Anti-Submarine Warfare
The mission of anti-submarine
warfare is to locate, neutralize, and
defeat hostile submarine forces that
threaten Navy surface forces. Antisubmarine warfare can involve various
assets such as aircraft, ships, and
submarines which all search for hostile
submarines. These forces operate
together or independently to gain early
warning and detection, and to localize,
track, target, and attack submarine
threats.
Anti-submarine warfare training
addresses basic skills such as detecting
and classifying submarines, as well as
evaluating sounds to distinguish
between enemy submarines and friendly
submarines, ships, and marine life.
These integrated anti-submarine warfare
training exercises are conducted in
coordinated, at-sea training events
involving submarines, ships, and
aircraft.
Overview of the Major Training
Exercise Within the GOA Study Area
The training activities in the GOA
Study Area are considered to be a major
training exercise (MTE). A MTE, for
purposes of this rulemaking, is
PO 00000
Frm 00006
Fmt 4701
Sfmt 4702
comprised of several unit-level activities
conducted by several units operating
together, commanded and controlled by
a single Commander, and potentially
generating more than 100 hours of
active sonar. These exercises typically
employ an exercise scenario developed
to train and evaluate the exercise
participants in tactical and operational
tasks. In a MTE, most of the activities
being directed and coordinated by the
Commander in charge of the exercise are
identical in nature to the activities
conducted during individual, crew, and
smaller unit-level training events. In a
MTE, however, these disparate training
tasks are conducted in concert, rather
than in isolation. At most, only one
MTE would occur in the GOA Study
Area per year (over a maximum of 21
days).
Description of Stressors
The Navy uses a variety of sensors,
platforms, weapons, and other devices,
including ones used to ensure the safety
of Sailors and Marines, to meet its
mission. Training with these systems
may introduce sound and energy into
the environment. The proposed training
activities were evaluated to identify
specific components that could act as
stressors by having direct or indirect
impacts on the environment. This
analysis included identification of the
spatial variation of the identified
stressors. The following subsections
describe the acoustic and explosive
stressors for marine mammals and their
habitat (including prey species) within
the GOA Study Area. Each description
contains a list of activities that may
generate the stressor. Stressor/resource
interactions that were determined to
have de minimis or no impacts (e.g.,
vessel noise, aircraft noise, weapons
noise, and high-altitude (greater than 10
m above the water surface) explosions)
were not carried forward for analysis in
the Navy’s rulemaking/LOA application.
The Navy fully considered the
possibility of vessel strike, conducted an
analysis, and determined that requesting
take of marine mammals by vessel strike
was not warranted. Although the Navy
did not request take for vessel strike,
NMFS also fully analyzed the potential
for vessel strike of marine mammals as
part of this rulemaking. Therefore, this
stressor is discussed in detail below. No
Sinking Exercise (SINKEX) events are
proposed in the GOA Study Area for
this rulemaking, nor is establishment
and use of a Portable Undersea Tracking
Range (PUTR) proposed. NMFS
reviewed the Navy’s analysis and
conclusions on de minimis and noimpact sources, included in Section
3.8.3 (Environmental Consequences) of
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
the 2020 GOA DSEIS/OEIS and finds
them complete and supportable.
lotter on DSK11XQN23PROD with PROPOSALS2
Acoustic Stressors
Acoustic stressors include acoustic
signals emitted into the water for a
specific purpose, such as sonar, other
transducers (devices that convert energy
from one form to another—in this case,
into sound waves), incidental sources of
broadband sound produced as a
byproduct of vessel movement, aircraft
transits, and use of weapons or other
deployed objects. Explosives also
produce broadband sound but are
characterized separately from other
acoustic sources due to their unique
hazardous characteristics.
Characteristics of each of these sound
sources are described in the following
sections.
In order to better organize and
facilitate the analysis of approximately
300 sources of underwater sound used
by the Navy, including sonar and other
transducers and explosives, a series of
source classifications, or source bins,
were developed. The source
classification bins do not include the
broadband noise produced incidental to
vessel movement, aircraft transits, and
weapons firing. Noise produced from
vessel movement, aircraft transits, and
use of weapons or other deployed
objects is not carried forward because
those activities were found to have de
minimis or no impacts, as described
above.
The use of source classification bins
provides the following benefits:
• Provides the ability for new sensors
or munitions to be covered under
existing authorizations, as long as those
sources fall within the parameters of a
‘‘bin;’’
• Improves efficiency of source
utilization data collection and reporting
requirements anticipated under the
MMPA authorizations;
• Ensures a precautionary approach
to all impact estimates, as all sources
within a given class are modeled as the
most impactful source (highest source
level, longest duty cycle, or largest net
explosive weight) within that bin;
• Allows analyses to be conducted in
a more efficient manner, without any
compromise of analytical results; and
• Provides a framework to support
the reallocation of source usage (hours/
explosives) between different source
bins, as long as the total numbers of
takes remain within the overall
analyzed and authorized limits. This
flexibility is required to support
evolving Navy training and testing
requirements, which are linked to real
world events.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
Sonar and Other Transducers
Active sonar and other transducers
emit non-impulsive sound waves into
the water to detect objects, navigate
safely, and communicate. Passive sonars
differ from active sound sources in that
they do not emit acoustic signals; rather,
they only receive acoustic information
about the environment, or listen. In this
proposed rule, the terms sonar and other
transducers will be used to indicate
active sound sources unless otherwise
specified.
The Navy employs a variety of sonars
and other transducers to obtain and
transmit information about the undersea
environment. Some examples are midfrequency hull-mounted sonars used to
find and track enemy submarines; highfrequency small object detection sonars
used to detect mines; high-frequency
underwater modems used to transfer
data over short ranges; and extremely
high-frequency (greater than 200
kilohertz (kHz)) doppler sonars used for
navigation, like those used on
commercial and private vessels. The
characteristics of these sonars and other
transducers, such as source level, beam
width, directivity, and frequency,
depend on the purpose of the source.
Higher frequencies can carry more
information or provide more
information about objects off which they
reflect, but attenuate more rapidly.
Lower frequencies attenuate less
rapidly, so they may detect objects over
a longer distance, but with less detail.
Propagation of sound produced
underwater is highly dependent on
environmental characteristics such as
bathymetry, bottom type, water depth,
temperature, and salinity. The sound
received at a particular location will be
different than near the source due to the
interaction of many factors, including
propagation loss; how the sound is
reflected, refracted, or scattered; the
potential for reverberation; and
interference due to multi-path
propagation. In addition, absorption
greatly affects the distance over which
higher-frequency sounds propagate. The
effects of these factors are explained in
Appendix B (Acoustic and Explosive
Concepts) of the 2020 GOA DSEIS/OEIS.
Because of the complexity of analyzing
sound propagation in the ocean
environment, the Navy relies on
acoustic models in its environmental
analyses that consider sound source
characteristics and varying ocean
conditions across the TMAA. As noted
above, the Navy does not propose to use
sonar and other transducers within the
WMA.
The sound sources and platforms
typically used in naval activities
PO 00000
Frm 00007
Fmt 4701
Sfmt 4702
49661
analyzed in the Navy’s rulemaking/LOA
application are described in Appendix
A (Navy Activities Descriptions) of the
2020 GOA DSEIS/OEIS. Sonars and
other transducers used to obtain and
transmit information underwater during
Navy training activities generally fall
into several categories of use described
below.
Anti-Submarine Warfare
Sonar used during anti-submarine
warfare would impart the greatest
amount of acoustic energy of any
category of sonar and other transducers
analyzed in this proposed rule. Types of
sonars used to detect potential enemy
vessels include hull-mounted, towed,
line array, sonobuoy, and helicopter
dipping sonars. In addition, acoustic
targets and decoys (countermeasures)
may be deployed to emulate the sound
signatures of vessels or repeat received
signals.
Most anti-submarine warfare sonars
are mid-frequency (1–10 kHz) because
mid-frequency sound balances sufficient
resolution to identify targets with
distance over which threats can be
identified. However, some sources may
use higher or lower frequencies. Duty
cycles can vary widely, from rarely used
to continuously active. For example,
anti-submarine warfare sonars can be
wide angle in a search mode or highly
directional in a track mode.
Most anti-submarine warfare activities
involving submarines or submarine
targets would occur in waters greater
than 600 feet (ft; 183 m) deep due to
safety concerns about running aground
at shallower depths.
Navigation and Safety
Similar to commercial and private
vessels, Navy vessels employ
navigational acoustic devices, including
speed logs, Doppler sonars for ship
positioning, and fathometers. These may
be in use at any time for safe vessel
operation. These sources are typically
highly directional to obtain specific
navigational data.
Communication
Sound sources used to transmit data
(such as underwater modems), provide
location (pingers), or send a single brief
release signal to bottom-mounted
devices (acoustic release) may be used
throughout the TMAA. These sources
typically have low duty cycles and are
usually only used when it is desirable
to send a detectable acoustic message.
Classification of Sonar and Other
Transducers
Sonars and other transducers are
grouped into classes that share an
E:\FR\FM\11AUP2.SGM
11AUP2
49662
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
attribute, such as frequency range or
purpose. As detailed below, classes are
further sorted by bins based on the
frequency or bandwidth; source level;
and, when warranted, the application
for which the source would be used.
Unless stated otherwise, a reference
distance of 1 meter (m) is used for sonar
and other transducers.
• Frequency of the non-impulsive
acoustic source:
Æ Low-frequency sources operate
below 1 kHz;
Æ Mid-frequency sources operate at
and above 1 kHz, up to and including
10 kHz;
Æ High-frequency sources operate
above 10 kHz, up to and including 100
kHz; and
Æ Very-high-frequency sources
operate above 100 kHz but below 200
kHz.
• Sound pressure level:
Æ Greater than 160 decibels (dB)
referenced to 1 micropascal (re: 1 mPa),
but less than 180 dB re: 1 mPa;
Æ Equal to 180 dB re: 1 mPa and up
to and including 200 dB re: 1 mPa; and
Æ Greater than 200 dB re: 1 mPa.
• Application for which the source
would be used:
Æ Sources with similar functions that
have similar characteristics, such as
pulse length (duration of each pulse),
beam pattern, and duty cycle.
The bins used for classifying active
sonars and transducers that are
quantitatively analyzed in the TMAA
are shown in Table 1. While general
parameters or source characteristics are
shown in the table, actual source
parameters are classified.
TABLE 1—SONAR AND OTHER TRANSDUCERS QUANTITATIVELY ANALYZED IN THE TMAA
For annual training activities
Source class category
Bin
Description
Units
Mid-Frequency (MF) Tactical and non-tactical sources that produce signals from
1 to 10 kHz.
MF1
Hull-mounted surface ship sonars (e.g., AN/SQS–53C and
AN/SQS–60).
Hull-mounted submarine sonars (e.g., AN/BQQ–10).
Helicopter-deployed
dipping
sonars (e.g., AN/AQS–22).
Active acoustic sonobuoys
(e.g., DICASS).
Active underwater sound signal
devices (e.g., MK 84).
Hull-mounted surface ship sonars with an active duty
cycle greater than 80%.
Towed array surface ship sonars with an active duty
cycle greater than 80%.
Hull-mounted submarine sonars (e.g., AN/BQQ–10).
H
271
1,897
H
25
175
H
27
189
I
126
882
I
14
98
H
42
294
H
14
98
H
12
84
MF3
MF4
MF5
MF6
MF11
MF12
High-Frequency (HF) Tactical and nontactical sources that produce signals
greater than 10 kHz but less than 100
kHz.
Anti-Submarine Warfare (ASW) Tactical
sources used during ASW training activities.
HF1
Annual
7-Year total
ASW1
MF systems operating above
200 dB.
H
14
98
ASW2
MF Multistatic Active Coherent
sonobuoy (e.g., AN/SSQ–
125).
MF towed active acoustic
countermeasure
systems
(e.g., AN/SLQ–25).
MF expendable active acoustic
device
countermeasures
(e.g., MK3).
H
42
294
H
273
1,911
I
7
49
ASW3
ASW4
Notes: H = hours, I = count (e.g., number of individual pings or individual sonobuoys), DICASS = Directional Command Activated Sonobuoy
System.
lotter on DSK11XQN23PROD with PROPOSALS2
Explosive Stressors
The near-instantaneous rise from
ambient to an extremely high peak
pressure is what makes an explosive
shock wave potentially damaging.
Farther from an explosive, the peak
pressures decay and the explosive
waves propagate as an impulsive,
broadband sound. Several parameters
influence the effect of an explosive: the
weight of the explosive in the warhead,
the type of explosive material, the
boundaries and characteristics of the
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
propagation medium, and the
detonation depth in water. The net
explosive weight, which is the explosive
power of a charge expressed as the
equivalent weight of trinitrotoluene
(TNT), accounts for the first two
parameters. The effects of these factors
are explained in Appendix B (Acoustic
and Explosive Concepts) of the 2020
GOA DSEIS/OEIS.
Explosive Use
Explosive detonations during training
activities are from the use of explosive
PO 00000
Frm 00008
Fmt 4701
Sfmt 4702
bombs, and naval gun shells; however,
no in-water explosive detonations are
included as part of the training
activities. For purposes of the analysis
in this proposed rule, detonations
occurring in air at a height of 33 ft (10
m) or less above the water surface, and
detonations occurring directly on the
water surface, were modeled to detonate
at a depth of 0.3 ft (0.1 m) below the
water surface since there is currently no
other identified methodology for
modeling potential effects to marine
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
mammals that are underwater as a result
of detonations occurring in-air at or
above the surface of the ocean (within
10 m above the surface). This
conservative approach over-estimates
the potential underwater impacts due to
low-altitude and surface explosives by
assuming that all explosive energy is
released and remains under the water
surface.
Explosive stressors resulting from the
detonation of some munitions, such as
missiles and gun rounds used in air-air
and surface-air scenarios, occur at high
altitude. The resulting sound energy
from those detonations in air would not
impact marine mammals. The explosive
energy released by detonations in air
has been well studied, and basic
methods are available to estimate the
explosive energy exposure with distance
from the detonation (e.g., U.S.
Department of the Navy (1975)). In air,
the propagation of impulsive noise from
an explosion is highly influenced by
atmospheric conditions, including
temperature and wind. While basic
estimation methods do not consider the
unique environmental conditions that
may be present on a given day, they do
allow for approximation of explosive
energy propagation under neutral
atmospheric conditions. Explosions that
occur during Air Warfare would
typically be at a sufficient altitude that
a large portion of the sound refracts
upward due to cooling temperatures
with increased altitude. Based on an
understanding of the explosive energy
released by detonations in air,
detonations occurring in air at altitudes
greater than 10 m above the surface of
the ocean are not likely to result in
acoustic impacts on marine mammals;
therefore, these types of explosive
activities will not be discussed further
in this document. (Note that most of
these in-air detonations would occur at
49663
altitudes substantially greater than 10 m
above the surface of the ocean, as
described in further detail in section
3.0.4.2.2 (Explosions in Air) of the 2020
GOA DSEIS/OEIS.) Activities such as
air-surface bombing or surface-surface
gunnery scenarios may involve the use
of explosive munitions that detonate
upon impact with targets at or above the
water surface (within 10 m above the
surface). For these activities, acoustic
effects modeling was undertaken as
described below.
In order to organize and facilitate the
analysis of explosives, explosive
classification bins were developed. The
use of explosive classification bins
provides the same benefits as described
for acoustic source classification bins in
the Acoustic Stressors section, above.
The explosive bin types and the
number of explosives detonating at or
above the water surface in the TMAA
are shown in Table 2.
TABLE 2—EXPLOSIVE SOURCES QUANTITATIVELY ANALYZED THAT DETONATE AT OR ABOVE THE WATER SURFACE IN THE
TMAA
Explosives
(source class and net explosive weight (NEW))
(lb.) *
Number of explosives
with the specified activity
(annually)
Number of explosives
with the specified activity
(7-year total)
56
64
6
2
392
448
42
14
E5 (>5–10 lb. NEW) ................................................................................................................
E9 (>100–250 lb. NEW) ..........................................................................................................
E10 (>250–500 lb. NEW) ........................................................................................................
E12 (>650–1,000 lb. NEW) .....................................................................................................
lotter on DSK11XQN23PROD with PROPOSALS2
* All of the E5, E9, E10, and E12 explosives would occur in-air, at or above the surface of the water, and would also occur offshore away from
the continental shelf and slope beyond the 4,000-meter isobath.
Propagation of explosive pressure
waves in water is highly dependent on
environmental characteristics such as
bathymetry, bottom type, water depth,
temperature, and salinity, which affect
how the pressure waves are reflected,
refracted, or scattered; the potential for
reverberation; and interference due to
multi-path propagation. In addition,
absorption greatly affects the distance
over which higher-frequency
components of explosive broadband
noise can propagate. Appendix B
(Acoustic and Explosive Concepts) of
the 2020 GOA DSEIS/OEIS explains the
characteristics of explosive detonations
and how the above factors affect the
propagation of explosive energy in the
water. Because of the complexity of
analyzing sound propagation in the
ocean environment, the Navy relies on
acoustic models in its environmental
analyses that consider sound source
characteristics and varying ocean
conditions across the TMAA.
For in-air explosives detonating at or
above the water surface, the model
estimating acoustic impacts assumes
that all acoustic energy from the
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
detonation is underwater with no loss of
sound or energy into the air. Important
considerations must be factored into the
analysis of results with these modeling
assumptions, given that the peak
pressure and sound from a detonation in
air significantly decreases across the airwater interface as it is partially reflected
by the water’s surface and partially
transmitted underwater, as detailed in
the following paragraphs.
Detonation of an explosive in air
creates a supersonic high pressure shock
wave that expands outward from the
point of detonation (Kinney and
Graham, 1985; Swisdak, 1975). The
near-instantaneous rise from ambient to
an extremely high peak pressure is what
makes the explosive shock wave
potentially injurious to an animal
experiencing the rapid pressure change
(U.S. Department of the Navy, 2017a).
As the shock wave-front travels away
from the point of detonation, it slows
and begins to behave as an acoustic
wave-front travelling at the speed of
sound. Whereas a shock wave from a
detonation in-air has an abrupt peak
pressure, that same pressure disturbance
PO 00000
Frm 00009
Fmt 4701
Sfmt 4702
when transmitted through the water
surface results in an underwater
pressure wave that begins and ends
more gradually compared with the in-air
shock wave, and diminishes with
increasing depth and distance from the
source (Bolghasi et al., 2017; Chapman
and Godin, 2004; Cheng and Edwards,
2003; Moody, 2006; Richardson et al.,
1995; Sawyers, 1968; Sohn et al., 2000;
Swisdak, 1975; Waters and Glass, 1970;
Woods et al., 2015). The propagation of
the shock wave in-air and then
transitioning underwater is very
different from a detonation occurring
deep underwater where there is little
interaction with the surface. In the case
of an underwater detonation occurring
just below the surface, a portion of the
energy from the detonation would be
released into the air (referred to as
surface blow off), and at greater depths
a pulsating, air-filled cavitation bubble
would form, collapse, and reform
around the detonation point (Urick,
1983). The Navy’s acoustic effects
model for analyzing underwater impacts
on marine species does not account for
the loss of energy due to surface blow-
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49664
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
off or cavitation at depth. Both of these
phenomena would diminish the
magnitude of the acoustic energy
received by an animal under real-world
conditions (U.S. Department of the
Navy, 2018b).
To more completely analyze the
results predicted by the Navy’s acoustic
effects model from detonations
occurring in-air above the ocean surface,
it is necessary to consider the transfer of
energy across the air-water interface.
Much of the scientific literature on the
transferal of shock wave impulse across
the air-water interface has focused on
energy from sonic booms created by fast
moving aircraft flying at low altitudes
above the ocean (Chapman and Godin,
2004; Cheng and Edwards, 2003;
Moody, 2006; Sawyers, 1968; Waters
and Glass, 1970). The shock wave
created by a sonic boom is similar to the
propagation of a pressure wave
generated by an explosion (although
having a significantly slower rise in
peak pressure) and investigations of
sonic booms are somewhat informative.
Waters and Glass (1970) were also
investigating sonic booms, but their
methodology involved actual in-air
detonations. In those experiments, they
detonated blasting caps elevated 30 ft (9
m) above the surface in a flooded quarry
and measured the resulting pressure at
and below the surface to determine the
penetration of the shock wave across the
air-water interface. Microphones above
the water surface recorded the peak
pressure in-air, and hydrophones at
various shallow depths underwater
recorded the unreflected remainder of
the pressure wave after transition across
the air-water interface. The peak
pressure measurements were compared
and the results supported the theoretical
expectations for the penetration of a
pressure wave from air into water,
including the predicted exponential
decay of energy with distance from the
source underwater. In effect, the airwater interface acted as a low-pass filter
eliminating the high-frequency
components of the shock wave. At
incident angles greater than 14 degrees
perpendicular to the surface, most of the
shock wave from the detonation was
reflected off the water surface, which is
consistent with results from similar
research (Cheng and Edwards, 2003;
Moody, 2006; Yagla and Stiegler, 2003).
Given that marine mammals spend, on
average, up to 90 percent of their time
underwater (Costa, 1993; Costa and
Block, 2009), and the shock wave from
a detonation is only a few milliseconds
in duration, marine mammals are
unlikely to be exposed in-air when
surfaced.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
Vessel Strike
NMFS also considered the chance that
a vessel utilized in training activities
could strike a marine mammal in the
GOA Study Area, including both the
TMAA and WMA portions of the Study
Area. Vessel strikes have the potential to
result in incidental take from serious
injury and/or mortality. Vessel strikes
are not specific to any particular
training activity, but rather are a
limited, sporadic, and incidental result
of Navy vessel movement within a study
area. Vessel strikes from commercial,
recreational, and military vessels are
known to seriously injure and
occasionally kill cetaceans (Abramson et
al., 2011; Berman-Kowalewski et al.,
2010; Calambokidis, 2012; Douglas et
al., 2008; Laggner, 2009; Lammers et al.,
2003; Van der Hoop et al., 2012; Van der
Hoop et al., 2013), although reviews of
the literature on ship strikes mainly
involve collisions between commercial
vessels and whales (Jensen and Silber,
2003; Laist et al., 2001). Vessel speed,
size, and mass are all important factors
in determining both the potential
likelihood and impacts of a vessel strike
to marine mammals (Conn and Silber,
2013; Gende et al., 2011; Silber et al.,
2010; Vanderlaan and Taggart, 2007;
Wiley et al., 2016). For large vessels,
speed and angle of approach can
influence the severity of a strike.
Navy vessels transit at speeds that are
optimal for fuel conservation and to
meet training requirements. Vessels
used as part of the proposed specified
activities include ships, submarines,
unmanned vessels, and boats ranging in
size from small, 22 ft (7 m) rigid hull
inflatable boats to aircraft carriers with
lengths up to 1,092 ft (333 m). The
average speed of large Navy ships ranges
between 10 and 15 knots (kn; 19–28 km/
hr), and submarines generally operate at
speeds in the range of 8 to 13 kn (15 to
24 km/hr), while a few specialized
vessels can travel at faster speeds. Small
craft (for purposes of this analysis, less
than 18 m in length) have much more
variable speeds (0 to 50+ kn (0 to 93+
km/hr)), dependent on the activity), but
generally range from 10 to 14 kn (19–26
km/hr). From unpublished Navy data,
average median speed for large Navy
ships in the other Navy ranges from
2011–2015 varied from 5 to 10 kn (9 to
19 km/hr) with variations by ship class
and location (i.e., slower speeds close to
the coast). Similar patterns would occur
in the GOA Study Area. A full
description of Navy vessels that are
used during training activities can be
found in Section 1.2.1 and Section
2.4.2.1 of the 2011 GOA FEIS/OEIS.
PO 00000
Frm 00010
Fmt 4701
Sfmt 4702
While these speeds are representative
of most events, some vessels need to
temporarily operate outside of these
parameters for certain times or during
certain activities. For example, to
produce the required relative wind
speed over the flight deck, an aircraft
carrier engaged in flight operations must
adjust its speed through the water
accordingly. Also, there are other
instances, such as launch and recovery
of a small rigid hull inflatable boat;
vessel boarding, search, and seizure
training events; or retrieval of a target
when vessels would be dead in the
water or moving slowly ahead to
maintain steerage.
Large Navy vessels (greater than 18 m
in length) within the offshore areas of
range complexes operate differently
from commercial vessels in ways that
may reduce potential whale collisions.
Surface ships operated by or for the
Navy have multiple personnel assigned
to stand watch at all times when a ship
or surfaced submarine is moving
through the water (underway). A
primary duty of personnel standing
watch on surface ships is to detect and
report all objects and disturbances
sighted in the water that may indicate
a threat to the vessel and its crew, such
as debris, a periscope, surfaced
submarine, or surface disturbance. Per
vessel safety requirements, personnel
standing watch also report any marine
mammals sighted in the path of the
vessel as a standard collision avoidance
procedure. All vessels proceed at a safe
speed so they can take proper and
effective action to avoid a collision with
any sighted object or disturbance, and
can be stopped within a distance
appropriate to the prevailing
circumstances and conditions.
Detailed Description of Proposed
Activities
Proposed Training Activities
The Navy proposes to conduct a
single carrier strike group (CSG)
exercise which would last for a
maximum of 21 consecutive days in a
year. The CSG exercise is comprised of
several individual training activities.
Table 3 lists and describes those
individual activities that may result in
takes of marine mammals. The events
listed would occur intermittently during
the 21 days and could be simultaneous
and in the same general area within the
TMAA or could be independent and
spatially separate from other ongoing
activities. The table is organized
according to primary mission areas and
includes the activity name, associated
stressor(s), description and duration of
the activity, sound source bin, the areas
E:\FR\FM\11AUP2.SGM
11AUP2
49665
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
where the activities are conducted in
the GOA Study Area, the maximum
number of events per year in the 21-day
period, and the maximum number of
events over 7 years. Not all sound
sources are used with each activity. The
‘‘Annual # of Events’’ column indicates
the maximum number of times that
activity could occur during any single
year. The ‘‘7-Year # of Events’’ is the
maximum number of times an activity
would occur over the 7-year period of
the proposed regulations if the training
occurred each year and at the maximum
levels requested. The events listed
would occur intermittently during the
exercise over a maximum of 21 days.
The maximum number of activities may
not occur in some years, and
historically, training has occurred only
every other year. However, to conduct a
conservative analysis, NMFS analyzed
the maximum times these activities
could occur over one year and 7 years.
The 2020 GOA DSEIS/OEIS includes
more detailed activity descriptions.
(Note the Navy proposes no lowfrequency active sonar (LFAS) use for
the activities in this rulemaking.)
TABLE 3—PROPOSED TRAINING ACTIVITIES ANALYZED FOR THE 7-YEAR PERIOD IN THE GOA STUDY AREA
Stressor
category
Activity
Description
Annual # of
events
Source bin
7-year # of
events
Surface Warfare
Explosive ....
Gunnery Exercise, Surface-toSurface (GUNEX–S–S).
Explosive ....
Bombing Exercise (Air-to-Surface) (BOMBEX [A–S]).
Surface ship crews fire inert
small-caliber, inert mediumcaliber, or large-caliber explosive rounds at surface targets.
Fixed-wing
aircraft
conduct
bombing exercises against
stationary floating targets,
towed targets, or maneuvering
targets.
E5 .................................
6
42
E9, E10, E12 ................
18
126
MF4, MF5, MF6 ............
22
154
MF5, MF6, ASW2 .........
13
91
ASW1, ASW3, MF1,
MF11, MF12.
ASW4, HF1, MF3 .........
2
14
2
14
Anti-Submarine Warfare (ASW)
Acoustic ......
Acoustic ......
Acoustic ......
Acoustic ......
Tracking
Exercise—Helicopter Helicopter crews search for,
(TRACKEX—Helo).
track, and detect submarines.
Tracking Exercise—Maritime Pa- Maritime patrol aircraft crews
trol Aircraft (TRACKEX—MPA).
search for, track, and detect
submarines.
Tracking
Exercise—Ship Surface ship crews search for,
(TRACKEX—Ship).
track, and detect submarines.
Tracking Exercise—Submarine Submarine crews search for,
(TRACKEX—Sub).
track, and detect submarines.
lotter on DSK11XQN23PROD with PROPOSALS2
Notes: S–S = Surface to Surface, A–S = Air to Surface.
Standard Operating Procedures
For training to be effective, personnel
must be able to safely use their sensors
and weapon systems as they are
intended to be used in military missions
and combat operations and to their
optimum capabilities. Standard
operating procedures applicable to
training have been developed through
years of experience, and their primary
purpose is to provide for safety
(including public health and safety) and
mission success. Because standard
operating procedures are essential to
safety and mission success, the Navy
considers them to be part of the
proposed specified activities, and has
included them in the analysis. In many
cases, there are benefits to natural and
cultural resources resulting from
standard operating procedures.
Standard operating procedures that are
recognized as having a potential benefit
to marine mammals during training
activities are noted below and discussed
in more detail within the 2020 GOA
DSEIS/OEIS.
• Vessel Safety;
• Weapons Firing Procedures;
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
• Target Deployment and Retrieval
Safety; and
• Towed In-Water Device Procedures.
Standard operating procedures (which
are implemented regardless of their
secondary benefits) are different from
mitigation measures (which are
designed entirely for the purpose of
avoiding or reducing impacts).
Information on mitigation measures is
provided in the Proposed Mitigation
Measures section below. Additional
information on standard operating
procedures is presented in Section 2.3.2
(Standard Operating Procedures) in the
2020 GOA DSEIS/OEIS.
Description of Marine Mammals and
Their Habitat in the Area of the
Specified Activities
Marine mammal species and their
associated stocks that have the potential
to occur in the GOA Study Area are
presented in Table 4 along with each
stock’s ESA and MMPA statuses,
abundance estimate and associated
coefficient of variation value, minimum
abundance estimate, and expected
occurrence in the GOA Study Area. The
PO 00000
Frm 00011
Fmt 4701
Sfmt 4702
Navy requested authorization to take
individuals of 16 marine mammal
species by Level A harassment and
Level B harassment, and NMFS has
conservatively analyzed and proposes to
authorize incidental take of two
additional species. The Navy does not
request authorization for any serious
injuries or mortalities of marine
mammals, and NMFS agrees that serious
injury and mortality is unlikely to occur
from the Navy’s activities. NMFS
recently designated critical habitat
under the Endangered Species Act
(ESA) for humpback whales in the
TMAA portion of the GOA Study Area,
and this designated critical habitat is
considered below (86 FR 21082; April
21, 2021). The WMA portion of the GOA
Study Area does not overlap ESAdesignated critical habitat for humpback
whales or any other species.
Information on the status,
distribution, abundance, population
trends, habitat, and ecology of marine
mammals in the GOA Study Area may
be found in Chapter 4 of the Navy’s
rulemaking/LOA application. NMFS has
reviewed this information and found it
E:\FR\FM\11AUP2.SGM
11AUP2
49666
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
to be accurate and complete. Additional
information on the general biology and
ecology of marine mammals is included
in the 2020 GOA DSEIS/OEIS. Table 4
incorporates the best available science,
including data from the 2020 U.S.
Pacific and the Alaska Marine Mammal
Stock Assessment Reports (SARs;
Carretta et al., 2021; Muto et al., 2021),
2021 draft U.S. Pacific and Alaska
Marine Mammal SARs, as well as
monitoring data from the Navy’s marine
mammal research efforts.
To better define marine mammal
occurrence in the TMAA, the portion of
the GOA Study Area where take of
marine mammals is anticipated to
occur, four regions within the TMAA
were defined (and are depicted in
Figure 3–1 of the Navy’s rulemaking/
LOA application), consistent with the
survey strata used by Rone et al. (2017)
during the most recent marine mammal
surveys in the TMAA. The four regions
are: inshore, slope, seamount, and
offshore.
Species Not Included in the Analysis
There has been no change in the
species unlikely to be present in the
GOA Study Area since the last MMPA
rulemaking process (82 FR 19530; April
27, 2017). The species carried forward
for analysis are those likely to be found
in the GOA Study Area based on the
most recent data available and do not
include species that may have once
inhabited or transited the area but have
not been sighted in recent years (e.g.,
species which were extirpated from
factors such as 19th and 20th century
commercial exploitation). Several
species and stocks that may be present
in the northeast Pacific Ocean generally
have an extremely low probability of
presence in the GOA Study Area. These
species and stocks are considered
extralimital (may be sightings, acoustic
detections, or stranding records, but the
GOA Study Area is outside the species’
range of normal occurrence) or rare
(occur in the GOA Study Area
sporadically, but sightings are rare).
These species and stocks include the
Eastern North Pacific Northern Resident
and the West Coast Transient stocks of
killer whale (Orcinus orca), beluga
whale (Delphinapterus leucas), false
killer whale (Pseudorca crassidens),
short-finned pilot whale (Globicephala
macrorhynchus), northern right whale
dolphin (Lissodelphis borealis), and
Risso’s dolphin (Grampus griseus).
The Eastern North Pacific Northern
Resident and the West Coast Transient
stocks of killer whale are considered
extralimital in the GOA Study Area.
Given the paucity of any beluga whale
sightings in the GOA (Laidre et al.
2000), the occurrence of this species
within the GOA Study Area is
considered extralimital. The GOA Study
Area is also outside of the normal range
of the false killer whale’s distribution in
the Pacific Ocean, and despite rare
stranding or sighting reports, the GOA
Study Area is outside of the normal
range of the short-finned pilot whale as
well. There are two sighting records of
northern right whale dolphins in the
Gulf of Alaska, but these are considered
extremely rare (U.S. Department of the
Navy 2006; NOAA 2012) and
extralimital in the GOA Study Area.
There are a few records of Risso’s
dolphins near the GOA Study Area;
however, their occurrence within the
GOA Study Area is rare, and therefore
Risso’s dolphin is considered
extralimital. NMFS agrees with the
Navy’s assessment that these species are
unlikely to occur in the GOA Study
Area and they are not discussed further.
One species of marine mammal, the
Northern sea otter, occurs in the Gulf of
Alaska but is managed by the U.S. Fish
and Wildlife Service and is not
considered further in this document.
TABLE 4—MARINE MAMMAL OCCURRENCE WITHIN THE GOA STUDY AREA
Common name
Scientific name
ESA
status,
MMPA
status,
strategic
(Y/N) 1
Stock
Stock abundance
(CV, Nmin, year of
most recent
abundance survey) 2
Annual
M/SI 3
PBR
Occurrence in GOA
study area 4
Order Cetacea—Suborder Mysticeti (baleen whales)
Family Balaenidae (right
whales):
North Pacific right
whale.
Family Balaenopteridae
(rorquals):
Humpback whale ....
Blue whale ..............
lotter on DSK11XQN23PROD with PROPOSALS2
Fin whale ................
Sei whale ................
Minke whale ...........
Family Eschrichtiidae
(gray whale):
Gray whale .............
VerDate Sep<11>2014
5 0.05
0
10,103 (0.3, 7,891,
2006).
83
26
-, -, Y
4,973 (0.05, 4,776,
2018).
28.7
≥48.6
Western North Pacific
E, D, Y
1,107 (0.3, 865, 2006)
3
2.8
Eastern North Pacific ..
E, D, Y
1,898 (0.085, 1,767,
2018).
4.1
≥19.4
Central North Pacific ...
E, D, Y
133 (1.09, 63, 2010) ....
0.1
0
Northeast Pacific .........
E, D, Y
3,168 (0.26, 2,554,
2013) 7.
519 (0.4, 374, 2014) ....
UNK .............................
5.1
0.6
0.75
UND
≥0.2
0
Rare.
Likely.
801
131
Likely: Highest numbers during seasonal
migrations (fall, winter, spring).
Eubalaena japonica .....
Eastern North Pacific ..
E, D, Y
31 (0.226, 26, 2008) ....
Megaptera
novaeangliae.
Central North Pacific 6
-, -, Y
California, Oregon, and
Washington 6.
Balaenoptera musculus
Balaenoptera physalus
Pacific 8
Balaenoptera borealis
Balaenoptera
acutorostrata.
Eastern North
Alaska ..........................
E, D, Y
-, -, N
Eschrichtius robustus ..
Eastern North Pacific ..
-, -, N
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00012
Fmt 4701
26,960 (0.05, 25,849,
2016).
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
Rare.
Seasonal; highest likelihood June to September.
Seasonal; highest likelihood June to September.
Seasonal; highest likelihood June to September.
Seasonal; highest likelihood June to December.
Seasonal; highest likelihood June to December.
Likely.
49667
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
TABLE 4—MARINE MAMMAL OCCURRENCE WITHIN THE GOA STUDY AREA—Continued
Common name
Scientific name
ESA
status,
MMPA
status,
strategic
(Y/N) 1
Stock
Western North Pacific
E, D, Y
Stock abundance
(CV, Nmin, year of
most recent
abundance survey) 2
290 (N/A, 271, 2016) ...
Occurrence in GOA
study area 4
Annual
M/SI 3
PBR
0.12
UNK
Rare: Individuals migrate through GOA.
UND
3.5
24
1
Likely.
2.8
0
Likely.
0.01
0
5.87
0.8
Rare; more likely inside
Prince William Sound
and Kenai Fjords.
Likely.
Order Cetacea—Suborder Odontoceti (toothed whales)
Family Physeteridae
(sperm whale):
Sperm whale ..........
Family Delphinidae (dolphins):
Killer whale .............
Pacific white-sided
dolphin.
Family Phocoenidae
(porpoises):
Harbor porpoise ......
Dall’s porpoise ........
Family Ziphiidae
(beaked whales):
Cuvier’s beaked
whale.
Baird’s beaked
whale.
Stejneger’s beaked
whale.
Physeter
macrocephalus.
North Pacific ................
E, D, Y
345 (0.43, 244, 2015) 9
Orcinus orca ................
Eastern North Pacific
Alaska Resident.
Eastern North Pacific
Offshore.
AT1 Transient ..............
-, -, N
10 2,347
Likely; More likely in
waters >1,000 m
depth, most often
>2,000 m.
-, -, N
(N/A, 2,347,
2012).
300 (0.1, 276, 2012) ....
-, D, Y
10 7
Eastern North Pacific
GOA, Aleutian Island, and Bering Sea
Transient.
North Pacific ................
-, -, N
10 587
-, -, N
26,880 (N/A, N/A,
1990).
UND
0
GOA .............................
-, -, Y
31,046 (0.21, N/A,
1998).
UND
72
Southeast Alaska ........
-, -, Y
12
34
Phocoenoides dalli ......
Alaska ..........................
-, -, N
1,354 (0.12, 1,224,
2012).
83,400 (0.097, 3,110,
2015).
Rare; Inshore and
Slope Regions, if
present.
Rare.
UND
37
Likely.
Ziphius cavirostris ........
Alaska ..........................
-, -, N
UNK .............................
UND
0
Likely.
Berardius bairdii ..........
Alaska ..........................
-, -, N
UNK .............................
UND
0
Likely.
Mesoplodon stejnegeri
Alaska ..........................
-, -, N
UNK .............................
UND
0
Likely.
2,592
112
Rare.
318
254
Likely; Inshore region.
14,011
>320
11,403
373
Rare (highest likelihood
April and May).
Likely.
451
1.8
Rare.
5,122
5.3
228
38
Seasonal (highest likelihood July–September).
Likely; Inshore region.
939
127
Likely; Inshore region.
1,253
413
Likely; Inshore region.
807
107
Likely; Inshore region.
9,785
163
Rare.
Lagenorhynchus
obliquidens.
Phocoena phocoena ...
(N/A, 7, 2018) .......
(N/A, 587, 2012)
Likely.
Order Carnivora—Suborder Pinnipedia 8
Family Otarieidae (fur
seals and sea lions):
Steller sea lion ........
Eastern U.S .................
-, -, N
Western U.S. ...............
E, D, Y
11 43,201
(N/A, 43,201,
2017).
11 52,932 (N/A, 52,932,
2013).
257,606 (N/A, 233,515,
2014).
626,618 (0.2, 530,376,
2019).
14,050 (N/A, 7,524,
2013).
California sea lion ...
Zalophus californianus
U.S ...............................
-, -, N
Northern fur seal ....
Callorhinus ursinus ......
Eastern Pacific ............
-, D, Y
California .....................
-, D, N
Mirounga angustirostris
California Breeding ......
-, -, N
187,386 (N/A, 85,369,
2013).
Phoca vitulina ..............
N Kodiak ......................
-, -, N
S Kodiak ......................
-, -, N
Prince William Sound ..
-, -, N
Cook Inlet/Shelikof ......
-, -, N
Unidentified ..................
-, -, N
8,677 (N/A, 7,609,
2017).
26,448 (N/A, 22,351,
2017).
44,756 (N/A, 41,776,
2015).
28,411 (N/A, 26,907,
2018).
184,697 (N/A, 163,086,
2013).
Family Phocidae (true
seals):
Northern elephant
seal.
Harbor seal .............
lotter on DSK11XQN23PROD with PROPOSALS2
Eumetopias jubatus .....
Ribbon seal ............
Histriophoca fasciata ...
Notes: CV = coefficient of variation, ESA = Endangered Species Act, GOA = Gulf of Alaska, m = meter(s), MMPA = Marine Mammal Protection Act, N/A = not
available, U.S. = United States, M/SI = mortality and serious injury, UNK = unknown, UND = undetermined.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00013
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
49668
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
1 Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the
ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds potential biological removal (PBR) or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under
the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
2 The stocks and stock abundance number are as provided in Carretta et al., 2021 and Muto et al., 2021. Nmin is the minimum estimate of stock abundance. In
some cases, CV is not applicable. NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region.
3 These values, found in NMFS’ SARs, represent annual levels of human-caused mortality and serious injury (M/SI) from all sources combined (e.g., commercial
fisheries, ship strike). Annual mortality and serious injury (M/SI) often cannot be determined precisely and is in some cases presented as a minimum value or range.
A CV associated with estimated mortality due to commercial fisheries is presented in some cases.
4 RARE: The distribution of the species is near enough to the GOA Study Area that the species could occur there, or there are a few confirmed sightings. LIKELY:
Year-round sightings or acoustic detections of the species in the GOA Study Area, although there may be variation in local abundance over the year. SEASONAL:
Species absence and presence as documented by surveys or acoustic monitoring. Regions within the GOA Study Area follow those presented in Rone et al. (2015);
Rone et al. (2009); Rone et al. (2014); Rone et al. (2017): inshore, slope, seamount, and offshore.
5 See SAR for more details
6 Humpback whales in the Central North Pacific stock and the California, Oregon, and Washington stock are from three Distinct Population Segments based on animals identified in breeding areas in Hawaii, Mexico, and Central America (Carretta et al., 2021; Muto et al., 2021; National Marine Fisheries Service, 2016c).
7 The SAR reports this stock abundance assessment as provisional and notes that it is an underestimate for the entire stock because it is based on surveys which
covered only a small portion of the stock’s range.
8 This analysis assumes that these individuals are from the Eastern North Pacific stock; however, they are not discussed in the West Coast or the Alaska Stock Assessment Reports (Carretta et al., 2021; Muto et al., 2021).
9 The SAR reports that this is an underestimate for the entire stock because it is based on surveys of a small portion of the stock’s extensive range and it does not
account for animals missed on the trackline or for females and juveniles in tropical and subtropical waters.
10 Stock abundance is based on counts of individual animals identified from photo-identification catalogues. Surveys for abundance estimates of these stocks are
conducted infrequently.
11 Stock abundance is the best estimate of pup and non-pup counts, which have not been corrected to account for animals at sea during abundance surveys.
Below, we consider additional
information about the marine mammals
in the area of the specified activities that
informs our analysis, such as identifying
known areas of important habitat or
behaviors, or where Unusual Mortality
Events (UME) have been designated.
lotter on DSK11XQN23PROD with PROPOSALS2
Critical Habitat
On April 21, 2021 (86 FR 21082),
NMFS published a final rule designating
critical habitat for the endangered
Western North Pacific DPS, the
endangered Central America DPS, and
the threatened Mexico DPS of
humpback whales, including specific
marine areas located off the coasts of
California, Oregon, Washington, and
Alaska. Based on consideration of
national security, economic impacts,
and data deficiency in some areas,
NMFS excluded certain areas from the
designation for each DPS.
NMFS identified prey species,
primarily euphausiids and small pelagic
schooling fishes (see the final rule for
particular prey species identified for
each DPS; 86 FR 21082; April 21, 2021)
of sufficient quality, abundance, and
accessibility within humpback whale
feeding areas to support feeding and
population growth, as an essential
habitat feature. NMFS, through a critical
habitat review team (CHRT), also
considered inclusion of migratory
corridors and passage features, as well
as sound and the soundscape, as
essential habitat features. However,
NMFS did not include either, as the
CHRT concluded that the best available
science did not allow for identification
of any consistently used migratory
corridors or definition of any physical,
essential migratory or passage
conditions for whales transiting
between or within habitats of the three
DPSs. The best available science also
currently does not enable NMFS to
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
identify a sound-related habitat feature
that is essential to the conservation of
humpback whales.
NMFS considered the co-occurrence
of this designated humpback whale
critical habitat and the GOA Study Area.
Figure 4–1 of the Navy’s rulemaking/
LOA application shows the overlap of
the humpback whale critical habitat
with the TMAA. As shown in the
Navy’s rulemaking/LOA application, the
TMAA overlaps with humpback whale
critical habitat Unit 5 (destination for
whales from the Hawaii, Mexico, and
Western North Pacific DPSs;
Calambokidis et al., 2008) and Unit 8
(destination for whales from the Hawaii
and Mexico DPSs (Baker et al., 1986,
Calambokidis et al., 2008); Western
North Pacific DPS whales have not been
photo-identified in this specific area,
but presence has been inferred based on
available data indicating that humpback
whales from Western North Pacific
wintering areas occur in the Gulf of
Alaska (NMFS 2020, Table C5)).
Approximately 4 percent of the
humpback whale critical habitat in the
GOA region overlaps with the TMAA,
and approximately 2 percent of critical
habitat in both the GOA and U.S. west
coast regions combined overlaps with
the TMAA. The WMA portion of the
GOA Study Area does not overlap ESAdesignated critical habitat for humpback
whales.
As noted above in the Geographical
Region section, the TMAA boundary
was intentionally designed to avoid
ESA-designated Western DPS (MMPA
Western U.S. stock) Steller sea lion
critical habitat.
Biologically Important Areas
BIAs include areas of known
importance for reproduction, feeding, or
migration, or areas where small and
resident populations are known to occur
PO 00000
Frm 00014
Fmt 4701
Sfmt 4702
(Van Parijs, 2015). Unlike ESA critical
habitat, these areas are not formally
designated pursuant to any statute or
law, but are a compilation of the best
available science intended to inform
impact and mitigation analyses. An
interactive map of BIAs may be found
here: https://cetsound.noaa.gov/
biologically-important-area-map.
The WMA does not overlap with any
known BIAs. BIAs in the GOA that
overlap portions of the TMAA include
the following feeding and migration
areas: North Pacific right whale feeding
BIA (June–September); Gray whale
migratory corridor BIA (November–
January, southbound; March–May,
northbound) (Ferguson et al., 2015). Fin
whale feeding areas (east, west, and
southwest of Kodiak Island) occur to the
west of the TMAA and gray whale
feeding areas occur both east (Southeast
Alaska) and west (Kodiak Island) of the
TMAA; however, these feeding areas are
located well outside of (≤ 20 nmi (37
km)) the TMAA and beyond the Navy’s
estimated range to effects for take by
Level A harassment and Level B
harassment.
A portion of the North Pacific right
whale feeding BIA overlaps with the
western side of the TMAA by
approximately 2,051 square kilometers
(km2; approximately 1.4 percent of the
TMAA, and 7 percent of the feeding
BIA). A small portion of the gray whale
migration corridor BIA also overlaps
with the western side of the TMAA by
approximately 1,582 km2
(approximately 1 percent of the TMAA,
and 1 percent of the migration corridor
BIA). To mitigate impacts to marine
mammals in these BIAs, the Navy
would implement several procedural
mitigation measures and mitigation
areas (described in the Proposed
Mitigation Measures section).
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
Unusual Mortality Events (UMEs)
A UME is defined under Section
410(6) of the MMPA as a stranding that
is unexpected; involves a significant
die-off of any marine mammal
population; and demands immediate
response. There is one UME that is
applicable to our evaluation of the
Navy’s activities in the GOA Study
Area. The gray whale UME along the
west coast of North America is active
and involves ongoing investigations in
the GOA that inform our analysis are
discussed below.
Gray Whale UME
Since January 1, 2019, elevated gray
whale strandings have occurred along
the west coast of North America, from
Mexico to Canada. As of June 3, 2022,
there have been a total of 578 strandings
along the coasts of the United States,
Canada, and Mexico, with 278 of those
strandings occurring along the U.S.
coast. Of the strandings on the U.S.
coast, 118 have occurred in Alaska, 66
in Washington, 14 in Oregon, and 80 in
California. Full or partial necropsy
examinations were conducted on a
subset of the whales. Preliminary
findings in several of the whales have
shown evidence of emaciation. These
findings are not consistent across all of
the whales examined, so more research
is needed. As part of the UME
investigation process, NOAA has
assembled an independent team of
scientists to coordinate with the
Working Group on Marine Mammal
Unusual Mortality Events to review the
data collected, sample stranded whales,
consider possible causal-linkages
between the mortality event and recent
ocean and ecosystem perturbations, and
determine the next steps for the
investigation. Please refer to: https://
www.fisheries.noaa.gov/national/
marine-life-distress/2019-2022-graywhale-unusual-mortality-event-alongwest-coast-and for more information on
this UME.
lotter on DSK11XQN23PROD with PROPOSALS2
Marine Mammal Hearing
Hearing is the most important sensory
modality for marine mammals
underwater, and exposure to
anthropogenic sound can have
deleterious effects. To appropriately
assess the potential effects of exposure
to sound, it is necessary to understand
the frequency ranges marine mammals
are able to hear. Current data indicate
that not all marine mammal species
have equal hearing capabilities (e.g.,
Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008).
To reflect this, Southall et al. (2007)
recommended that marine mammals be
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
divided into functional hearing groups
based on directly measured or estimated
hearing ranges on the basis of available
behavioral response data, audiograms
derived using auditory evoked potential
techniques, anatomical modeling, and
other data. Note that no direct
measurements of hearing ability have
been successfully completed for
mysticetes (i.e., low-frequency
cetaceans). Subsequently, NMFS (2018)
described generalized hearing ranges for
these marine mammal hearing groups.
Generalized hearing ranges were chosen
based on the approximately 65 dB
threshold from the normalized
composite audiograms, with the
exception for lower limits for lowfrequency cetaceans where the lower
bound was deemed to be biologically
implausible and the lower bound from
Southall et al. (2007) retained. The
functional groups and the associated
frequencies are indicated below (note
that these frequency ranges correspond
to the range for the composite group,
with the entire range not necessarily
reflecting the capabilities of every
species within that group):
• Low-frequency cetaceans
(mysticetes): generalized hearing is
estimated to occur between
approximately 7 Hz and 35 kHz;
• Mid-frequency cetaceans (larger
toothed whales, beaked whales, and
most delphinids): generalized hearing is
estimated to occur between
approximately 150 Hz and 160 kHz;
• High-frequency cetaceans
(porpoises, river dolphins, and members
of the genera Kogia and
Cephalorhynchus; including two
members of the genus Lagenorhynchus,
on the basis of recent echolocation data
and genetic data): generalized hearing is
estimated to occur between
approximately 275 Hz and 160 kHz;
• Pinnipeds in water; Phocidae (true
seals): generalized hearing is estimated
to occur between approximately 50 Hz
to 86 kHz; and
• Pinnipeds in water; Otariidae (eared
seals): generalized hearing is estimated
to occur between 60 Hz and 39 kHz.
The pinniped functional hearing
group was modified from Southall et al.
(2007) on the basis of data indicating
that phocid species have consistently
demonstrated an extended frequency
range of hearing compared to otariids,
especially in the higher frequency range
(Hemila¨ et al., 2006; Kastelein et al.,
2009; Reichmuth and Holt, 2013).
For more details concerning these
groups and associated frequency ranges,
please see NMFS (2018) for a review of
the available information.
PO 00000
Frm 00015
Fmt 4701
Sfmt 4702
49669
Potential Effects of Specified Activities
on Marine Mammals and Their Habitat
This section includes a discussion of
the ways that components of the
specified activity may impact marine
mammals and their habitat. The
Estimated Take of Marine Mammals
section later in this rule includes a
quantitative analysis of the number of
instances of take that could occur from
these activities. The Preliminary
Analysis and Negligible Impact
Determination section considers the
content of this section, the Estimated
Take of Marine Mammals section, and
the Proposed Mitigation Measures
section to draw conclusions regarding
the likely impacts of these activities on
the reproductive success or survivorship
of individuals and whether those
impacts on individuals are likely to
adversely affect the species through
effects on annual rates of recruitment or
survival.
The Navy has requested authorization
for the take of marine mammals that
may occur incidental to training
activities in the GOA Study Area. The
Navy analyzed potential impacts to
marine mammals in its rulemaking/LOA
application. NMFS carefully reviewed
the information provided by the Navy
along with independently reviewing
applicable scientific research and
literature and other information to
evaluate the potential effects of the
Navy’s activities on marine mammals,
which are presented in this section. (As
noted above, activities that would result
in take of marine mammals would only
occur in the TMAA portion of the GOA
Study Area.)
Other potential impacts to marine
mammals from training activities in the
GOA Study Area were analyzed in the
Navy’s rulemaking/LOA application as
well as in the 2020 GOA DSEIS/OEIS
and 2022 Supplement to the 2020 GOA
DSEIS/OEIS, in consultation with
NMFS as a cooperating agency, and
determined to be unlikely to result in
marine mammal take. These include
incidental take from vessel strike and
serious injury or mortality from
explosives. Therefore, the Navy did not
request authorization for incidental take
of marine mammals by vessel strike or
serious injury or mortality from
explosives from its proposed specified
activities. NMFS has carefully
considered the information in the 2020
GOA DSEIS/OEIS, the 2022 Supplement
to the 2020 GOA DSEIS/OEIS, and all
other pertinent information and agrees
that incidental take is unlikely to occur
from these sources. NMFS conducted a
detailed analysis of the potential for
vessel strike, and based on that analysis,
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49670
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
NMFS does not anticipate vessel strikes
of large whales or smaller marine
mammals in the GOA Study Area. In
this proposed rule, NMFS analyzes the
potential effects of the Navy’s activities
on marine mammals in the GOA Study
Area, focusing primarily on the activity
components that may cause the take of
marine mammals: exposure to acoustic
or explosive stressors including nonimpulsive (sonar and other transducers)
and impulsive (explosives) stressors.
For the purpose of MMPA incidental
take authorizations, NMFS’ effects
assessments serve four primary
purposes: (1) to determine whether the
specified activities would have a
negligible impact on the affected species
or stocks of marine mammals (based on
whether it is likely that the activities
would adversely affect the species or
stocks through effects on annual rates of
recruitment or survival); (2) to
determine whether the specified
activities would have an unmitigable
adverse impact on the availability of the
species or stocks for subsistence uses;
(3) to prescribe the permissible methods
of taking (i.e., Level B harassment
(behavioral disturbance and temporary
threshold shift (TTS)), Level A
harassment (permanent threshold shift
(PTS) and non-auditory injury), serious
injury, or mortality), including
identification of the number and types
of take that could occur by harassment,
serious injury, or mortality, and to
prescribe means of effecting the least
practicable adverse impact on the
species or stocks and their habitat (i.e.,
mitigation measures); and (4) to
prescribe requirements pertaining to
monitoring and reporting.
In this section, NMFS provides a
description of the ways marine
mammals potentially could be affected
by these activities in the form of
mortality, physical trauma, sensory
impairment (permanent and temporary
threshold shifts and acoustic masking),
physiological responses (particularly
stress responses), behavioral
disturbance, or habitat effects. The
Estimated Take of Marine Mammals
section discusses how the potential
effects on marine mammals from nonimpulsive and impulsive sources relate
to the MMPA definitions of Level A
Harassment and Level B Harassment,
and quantifies those effects that rise to
the level of a take. The Preliminary
Analysis and Negligible Impact
Determination section assesses whether
the proposed authorized take would
have a negligible impact on the affected
species and stocks.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
Potential Effects of Underwater Sound
Anthropogenic sounds cover a broad
range of frequencies and sound levels
and can have a range of highly variable
impacts on marine life, from none or
minor to potentially severe responses,
depending on received levels, duration
of exposure, behavioral context, and
various other factors. The potential
effects of underwater sound from active
acoustic sources can possibly result in
one or more of the following: temporary
or permanent hearing impairment, nonauditory physical or physiological
effects, behavioral response, stress, and
masking (Richardson et al., 1995;
Gordon et al., 2004; Nowacek et al.,
2007; Southall et al., 2007; Go¨tz et al.,
2009, Southall et al., 2019a). The degree
of effect is intrinsically related to the
signal characteristics, received level,
distance from the source, and duration
of the sound exposure. In general,
sudden, high level sounds can cause
hearing loss, as can longer exposures to
lower level sounds. Temporary or
permanent loss of hearing can occur
after exposure to noise, and occurs
almost exclusively for noise within an
animal’s hearing range. Note that in the
following discussion, we refer in many
cases to a review article concerning
studies of noise-induced hearing loss
conducted from 1996–2015 (i.e.,
Finneran, 2015). For study-specific
citations, please see that work. We first
describe general manifestations of
acoustic effects before providing
discussion specific to the Navy’s
activities.
Richardson et al. (1995) described
zones of increasing intensity of effect
that might be expected to occur, in
relation to distance from a source and
assuming that the signal is within an
animal’s hearing range. First is the area
within which the acoustic signal would
be audible (potentially perceived) to the
animal, but not strong enough to elicit
any overt behavioral or physiological
response. The next zone corresponds
with the area where the signal is audible
to the animal and of sufficient intensity
to elicit behavioral or physiological
responsiveness. Third is a zone within
which, for signals of high intensity, the
received level is sufficient to potentially
cause discomfort or tissue damage to
auditory systems. Overlaying these
zones to a certain extent is the area
within which masking (i.e., when a
sound interferes with or masks the
ability of an animal to detect a signal of
interest that is above the absolute
hearing threshold) may occur; the
masking zone may be highly variable in
size.
PO 00000
Frm 00016
Fmt 4701
Sfmt 4702
We also describe more severe
potential effects (i.e., certain nonauditory physical or physiological
effects). Potential effects from impulsive
sound sources can range in severity
from effects such as behavioral
disturbance or tactile perception to
physical discomfort, slight injury of the
internal organs and the auditory system,
or mortality (Yelverton et al., 1973).
Non-auditory physiological effects or
injuries that theoretically might occur in
marine mammals exposed to high level
underwater sound or as a secondary
effect of extreme behavioral reactions
(e.g., change in dive profile as a result
of an avoidance reaction) include
neurological effects, bubble formation,
resonance effects, and other types of
organ or tissue damage (Cox et al., 2006;
Southall et al., 2007; Zimmer and
Tyack, 2007; Tal et al., 2015).
Acoustic Sources
Direct Physiological Effects
Non-impulsive sources of sound can
cause direct physiological effects
including noise-induced loss of hearing
sensitivity (or ‘‘threshold shift’’),
nitrogen decompression, acousticallyinduced bubble growth, and injury due
to sound-induced acoustic resonance.
Only noise-induced hearing loss is
anticipated to occur due to the Navy’s
activities. Acoustically-induced (or
mediated) bubble growth and other
pressure-related physiological impacts
are addressed below, but are not
expected to result from the Navy’s
activities. Separately, an animal’s
behavioral reaction to an acoustic
exposure might lead to physiological
effects that might ultimately lead to
injury or death, which is discussed later
in the Stranding and Mortality
subsection.
Hearing Loss—Threshold Shift
Marine mammals exposed to highintensity sound, or to lower-intensity
sound for prolonged periods, can
experience hearing threshold shift,
which is the loss of hearing sensitivity
at certain frequency ranges after
cessation of sound (Finneran, 2015).
Threshold shift can be permanent (PTS),
in which case the loss of hearing
sensitivity is not fully recoverable, or
temporary (TTS), in which case the
animal’s hearing threshold would
recover over time (Southall et al., 2007).
TTS can last from minutes or hours to
days (i.e., there is recovery back to
baseline/pre-exposure levels), can occur
within a specific frequency range (i.e.,
an animal might only have a temporary
loss of hearing sensitivity within a
limited frequency band of its auditory
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
range), and can be of varying amounts
(e.g., an animal’s hearing sensitivity
might be reduced by only 6 dB or
reduced by 30 dB). While there is no
simple functional relationship between
TTS and PTS or other auditory injury
(e.g., neural degeneration), as TTS
increases, the likelihood that additional
exposure sound pressure level (SPL) or
duration will result in PTS or other
injury also increases (see also the 2020
GOA DSEIS/OEIS for additional
discussion). Exposure thresholds for the
onset of PTS or other auditory injury are
defined by the amount of sound energy
that results in 40 dB of TTS. This value
is informed by experimental data, and is
used as a proxy for the onset of auditory
injury; i.e., it is assumed that exposures
beyond those capable of causing 40 dB
of TTS have the potential to result in
PTS or other auditory injury (e.g., loss
of cochlear neuron synapses, even in the
absence of PTS). In severe cases of PTS,
there can be total or partial deafness,
while in most cases the animal has an
impaired ability to hear sounds in
specific frequency ranges (Kryter, 1985).
When PTS occurs, there is physical
damage to the sound receptors in the ear
(i.e., tissue damage), whereas TTS
represents primarily tissue fatigue and
is reversible (Southall et al., 2007). PTS
is permanent (i.e., there is incomplete
recovery back to baseline/pre-exposure
levels), but also can occur in a specific
frequency range and amount as
mentioned above for TTS. In addition,
other investigators have suggested that
TTS is within the normal bounds of
physiological variability and tolerance
and does not represent physical injury
(e.g., Ward, 1997). Therefore, NMFS
does not consider TTS to constitute
auditory injury.
The following physiological
mechanisms are thought to play a role
in inducing auditory threshold shift:
effects to sensory hair cells in the inner
ear that reduce their sensitivity;
modification of the chemical
environment within the sensory cells;
residual muscular activity in the middle
ear; displacement of certain inner ear
membranes; increased blood flow; and
post-stimulatory reduction in both
efferent and sensory neural output
(Southall et al., 2007). The amplitude,
duration, frequency, temporal pattern,
and energy distribution of sound
exposure all can affect the amount of
associated threshold shift and the
frequency range in which it occurs.
Generally, the amount of threshold shift,
and the time needed to recover from the
effect, increase as amplitude and
duration of sound exposure increases.
Human non-impulsive noise exposure
guidelines are based on the assumption
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
that exposures of equal energy (the same
sound exposure level (SEL)) produce
equal amounts of hearing impairment
regardless of how the sound energy is
distributed in time (NIOSH, 1998).
Previous marine mammal TTS studies
have also generally supported this equal
energy relationship (Southall et al.,
2007). However, some more recent
studies concluded that for all noise
exposure situations the equal energy
relationship may not be the best
indicator to predict TTS onset levels
(Mooney et al., 2009a and 2009b; Kastak
et al., 2007). These studies highlight the
inherent complexity of predicting TTS
onset in marine mammals, as well as the
importance of considering exposure
duration when assessing potential
impacts. Generally, with sound
exposures of equal energy, those that
were quieter (lower SPL) with longer
duration were found to induce TTS
onset at lower levels than those of
louder (higher SPL) and shorter
duration. Less threshold shift will occur
from intermittent sounds than from a
continuous exposure with the same
energy (some recovery can occur
between intermittent exposures) (Kryter
et al., 1966; Ward, 1997; Mooney et al.,
2009a, 2009b; Finneran et al., 2010). For
example, one short but loud (higher
SPL) sound exposure may induce the
same impairment as one longer but
softer (lower SPL) sound, which in turn
may cause more impairment than a
series of several intermittent softer
sounds with the same total energy
(Ward, 1997). Additionally, though TTS
is temporary, very prolonged or
repeated exposure to sound strong
enough to elicit TTS, or shorter-term
exposure to sound levels well above the
TTS threshold can cause PTS, at least in
terrestrial mammals (Kryter, 1985;
Lonsbury-Martin et al., 1987).
PTS is considered auditory injury
(Southall et al., 2007). Irreparable
damage to the inner or outer cochlear
hair cells may cause PTS; however,
other mechanisms are also involved,
such as exceeding the elastic limits of
certain tissues and membranes in the
middle and inner ears and resultant
changes in the chemical composition of
the inner ear fluids (Southall et al.,
2007).
The NMFS Acoustic Technical
Guidance (NMFS, 2018), which was
used in the assessment of effects for this
rule, compiled, interpreted, and
synthesized the best available scientific
information for noise-induced hearing
effects for marine mammals to derive
updated thresholds for assessing the
impacts of noise on marine mammal
hearing. More recently, Southall et al.
(2019a) evaluated Southall et al. (2007)
PO 00000
Frm 00017
Fmt 4701
Sfmt 4702
49671
and used updated scientific information
to propose revised noise exposure
criteria to predict onset of auditory
effects in marine mammals (i.e., PTS
and TTS onset). Southall et al. (2019a)
note that the quantitative processes
described and the resulting exposure
criteria (i.e., thresholds and auditory
weighting functions) are largely
identical to those in Finneran (2016)
and NMFS (2018). They only differ in
that the Southall et al. (2019a) exposure
criteria are more broadly applicable as
they include all marine mammal species
(rather than only those under NMFS
jurisdiction) for all noise exposures
(both in air and underwater for
amphibious species) and, while the
hearing group compositions are
identical, they renamed the hearing
groups. Southall et al. (2021) updated
the behavioral response severity criteria
laid out in Southall et al. (2007) and
included recommendations on how to
present and score behavioral responses
in future work.
Many studies have examined noiseinduced hearing loss in marine
mammals (see Finneran (2015) and
Southall et al. (2019a) for summaries),
however for cetaceans, published data
on the onset of TTS are limited to the
captive bottlenose dolphin, beluga,
harbor porpoise, and Yangtze finless
porpoise, and for pinnipeds in water,
measurements of TTS are limited to
harbor seals, elephant seals, and
California sea lions. These studies
examine hearing thresholds measured in
marine mammals before and after
exposure to intense sounds. The
difference between the pre-exposure
and post-exposure thresholds can then
be used to determine the amount of
threshold shift at various post-exposure
times. NMFS has reviewed the available
studies, which are summarized below
(see also the 2020 GOA DSEIS/OEIS
which includes additional discussion
on TTS studies related to sonar and
other transducers).
• The method used to test hearing
may affect the resulting amount of
measured TTS, with neurophysiological
measures producing larger amounts of
TTS compared to psychophysical
measures (Finneran et al., 2007;
Finneran, 2015).
• The amount of TTS varies with the
hearing test frequency. As the exposure
SPL increases, the frequency at which
the maximum TTS occurs also increases
(Kastelein et al., 2014b). For high-level
exposures, the maximum TTS typically
occurs one-half to one octave above the
exposure frequency (Finneran et al.,
2007; Mooney et al., 2009a; Nachtigall
et al., 2004; Popov et al., 2011; Popov
et al., 2013; Schlundt et al., 2000;
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49672
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
Kastelein et al., 2021b; Kastelien et al.,
2022). The overall spread of TTS from
tonal exposures can therefore extend
over a large frequency range (i.e.,
narrowband exposures can produce
broadband (greater than one octave)
TTS).
• The amount of TTS increases with
exposure SPL and duration and is
correlated with SEL, especially if the
range of exposure durations is relatively
small (Kastak et al., 2007; Kastelein et
al., 2014b; Popov et al., 2014). As the
exposure duration increases, however,
the relationship between TTS and SEL
begins to break down. Specifically,
duration has a more significant effect on
TTS than would be predicted on the
basis of SEL alone (Finneran et al.,
2010a; Kastak et al., 2005; Mooney et
al., 2009a). This means if two exposures
have the same SEL but different
durations, the exposure with the longer
duration (thus lower SPL) will tend to
produce more TTS than the exposure
with the higher SPL and shorter
duration. In most acoustic impact
assessments, the scenarios of interest
involve shorter duration exposures than
the marine mammal experimental data
from which impact thresholds are
derived; therefore, use of SEL tends to
over-estimate the amount of TTS.
Despite this, SEL continues to be used
in many situations because it is
relatively simple, more accurate than
SPL alone, and lends itself easily to
scenarios involving multiple exposures
with different SPL.
• Gradual increases of TTS may not
be directly observable with increasing
exposure levels, before the onset of PTS
(Reichmuth et al., 2019). Similarly, PTS
can occur without measurable
behavioral modifications (Reichmuth et
al., 2019).
• The amount of TTS depends on the
exposure frequency. Sounds at low
frequencies, well below the region of
best sensitivity, are less hazardous than
those at higher frequencies, near the
region of best sensitivity (Finneran and
Schlundt, 2013). The onset of TTS—
defined as the exposure level necessary
to produce 6 dB of TTS (i.e., clearly
above the typical variation in threshold
measurements)—also varies with
exposure frequency. At low frequencies,
onset-TTS exposure levels are higher
compared to those in the region of best
sensitivity. For example, for harbor
porpoises exposed to one-sixth octave
noise bands at 16 kHz (Kastelein et al.,
2019f), 32 kHz (Kastelein et al., 2019d),
63 kHz (Kastelein et al., 2020a), and
88.4 kHz (Kastelein et al., 2020b), less
susceptibility to TTS was found as
frequency increased, whereas exposure
frequencies below ∼6.5 kHz showed an
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
increase in TTS susceptibility as
frequency increased and approached the
region of best sensitivity. Kastelein et al.
(2020b) showed a much higher onset of
TTS for a 88.5 kHz exposure as
compared to lower exposure frequencies
(i.e., 16 kHz (Kastelein et al., 2019) 1.5
kHz and 6.5 kHz (Kastelein et al.,
2020a)). For the 88.4 kHz test frequency,
a 185 dB re 1 micropascal squared per
second (mPa2-s) exposure resulted in 3.6
dB of TTS, and a 191 dB re 1 mPa2-s
exposure produced 5.2 dB of TTS at 100
kHz and 5.4 dB of TTS at 125 kHz.
Together, these new studies
demonstrate that the criteria for highfrequency (HF) cetacean auditory
impacts is likely to be conservative.
• TTS can accumulate across
multiple exposures, but the resulting
TTS will be less than the TTS from a
single, continuous exposure with the
same SEL (Finneran et al., 2010a;
Kastelein et al., 2014b; Kastelein et al.,
2015b; Mooney et al., 2009b). This
means that TTS predictions based on
the total, cumulative SEL will
overestimate the amount of TTS from
intermittent exposures such as sonars
and impulsive sources. The importance
of duty cycle in predicting the
likelihood of TTS is demonstrated
further in Kastelein et al. (2021b). The
authors found that reducing the duty
cycle of a sound generally reduced the
potential for TTS in California sea lions,
and that, further, California sea lions are
more susceptible to TTS than previously
believed at the 2 and 4 kHz frequencies
tested.
• The amount of observed TTS tends
to decrease with increasing time
following the exposure; however, the
relationship is not monotonic (i.e.,
increasing exposure does not always
increase TTS). The time required for
complete recovery of hearing depends
on the magnitude of the initial shift; for
relatively small shifts recovery may be
complete in a few minutes, while large
shifts (e.g., approximately 40 dB) may
require several days for recovery.
Recovery times are consistent for
similar-magnitude TTS, regardless of
the type of fatiguing sound exposure
(impulsive, continuous noise band, or
sinusoidal wave; (Kastelein et al.,
2019e)). Under many circumstances
TTS recovers linearly with the
logarithm of time (Finneran et al.,
2010a, 2010b; Finneran and Schlundt,
2013; Kastelein et al., 2012a; Kastelein
et al., 2012b; Kastelein et al., 2013a;
Kastelein et al., 2014b; Kastelein et al.,
2014c; Popov et al., 2011; Popov et al.,
2013; Popov et al., 2014). This means
that for each doubling of recovery time,
the amount of TTS will decrease by the
same amount (e.g., 6 dB recovery per
PO 00000
Frm 00018
Fmt 4701
Sfmt 4702
doubling of time). Please see Section
3.8.3.1.1.2 of the 2020 GOA DSEIS/OEIS
for discussion of additional threshold
shift literature.
Nachtigall et al. (2018) and Finneran
(2018) describe the measurements of
hearing sensitivity of multiple
odontocete species (bottlenose dolphin,
harbor porpoise, beluga, and false killer
whale) when a relatively loud sound
was preceded by a warning sound.
These captive animals were shown to
reduce hearing sensitivity when warned
of an impending intense sound. Based
on these experimental observations of
captive animals, the authors suggest that
wild animals may dampen their hearing
during prolonged exposures or if
conditioned to anticipate intense
sounds. Another study showed that
echolocating animals (including
odontocetes) might have anatomical
specializations that might allow for
conditioned hearing reduction and
filtering of low-frequency ambient
noise, including increased stiffness and
control of middle ear structures and
placement of inner ear structures
(Ketten et al., 2021). Finneran
recommends further investigation of the
mechanisms of hearing sensitivity
reduction in order to understand the
implications for interpretation of
existing TTS data obtained from captive
animals, notably for considering TTS
due to short duration, unpredictable
exposures.
Marine mammal hearing plays a
critical role in communication with
conspecifics and in interpretation of
environmental cues for purposes such
as predator avoidance and prey capture.
Depending on the degree (elevation of
threshold in dB), duration (i.e., recovery
time), and frequency range of TTS, and
the context in which it is experienced,
TTS can have effects on marine
mammals ranging from discountable to
serious, similar to those discussed in
auditory masking below. For example, a
marine mammal may be able to readily
compensate for a brief, relatively small
amount of TTS in a non-critical
frequency range that takes place during
a time where ambient noise is lower and
there are not as many competing sounds
present. Alternatively, a larger amount
and longer duration of TTS sustained
during a time when communication is
critical for successful mother/calf
interactions could have more serious
impacts if it were in the same frequency
band as the necessary vocalizations and
of a severity that impeded
communication. Animals exposed to
high levels of sound that would be
expected to result in this physiological
response would also be expected to
have behavioral responses of a
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
comparatively more severe or sustained
nature, which is potentially more
significant than simple existence of a
TTS. However, it is important to note
that TTS could occur due to longer
exposures to sound at lower levels so
that a behavioral response may not be
elicited.
Depending on the degree and
frequency range, the effects of PTS on
an animal could also range in severity,
although it is considered generally more
serious than TTS because it is a
permanent condition. Of note, reduced
hearing sensitivity as a simple function
of aging has been observed in marine
mammals, as well as humans and other
taxa (Southall et al., 2007), so we can
infer that strategies exist for coping with
this condition to some degree, though
likely not without some cost to the
animal.
Acoustically-Induced Bubble Formation
Due to Sonars and Other PressureRelated Impacts
One theoretical cause of injury to
marine mammals is rectified diffusion
(Crum and Mao, 1996), the process of
increasing the size of a bubble by
exposing it to a sound field. This
process could be facilitated if the
environment in which the ensonified
bubbles exist is supersaturated with gas.
Repetitive diving by marine mammals
can cause the blood and some tissues to
accumulate gas to a greater degree than
is supported by the surrounding
environmental pressure (Ridgway and
Howard, 1979). The deeper and longer
dives of some marine mammals (for
example, beaked whales) are
theoretically predicted to induce greater
supersaturation (Houser et al., 2001b). If
rectified diffusion were possible in
marine mammals exposed to high-level
sound, conditions of tissue
supersaturation could theoretically
speed the rate and increase the size of
bubble growth. Subsequent effects due
to tissue trauma and emboli would
presumably mirror those observed in
humans suffering from decompression
sickness.
It is unlikely that the short duration
(in combination with the source levels)
of sonar pings would be long enough to
drive bubble growth to any substantial
size, if such a phenomenon occurs.
However, an alternative but related
hypothesis has also been suggested:
stable bubbles could be destabilized by
high-level sound exposures such that
bubble growth then occurs through
static diffusion of gas out of the tissues.
In such a scenario the marine mammal
would need to be in a gassupersaturated state for a long enough
period of time for bubbles to become of
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
a problematic size. Recent research with
ex vivo supersaturated bovine tissues
suggested that, for a 37 kHz signal, a
sound exposure of approximately 215
dB referenced to (re) 1 mPa would be
required before microbubbles became
destabilized and grew (Crum et al.,
2005). Assuming spherical spreading
loss and a nominal sonar source level of
235 dB re: 1 mPa at 1 m, a whale would
need to be within 10 m (33 ft) of the
sonar dome to be exposed to such sound
levels. Furthermore, tissues in the study
were supersaturated by exposing them
to pressures of 400–700 kilopascals for
periods of hours and then releasing
them to ambient pressures. Assuming
the equilibration of gases with the
tissues occurred when the tissues were
exposed to the high pressures, levels of
supersaturation in the tissues could
have been as high as 400–700 percent.
These levels of tissue supersaturation
are substantially higher than model
predictions for marine mammals
(Houser et al., 2001; Saunders et al.,
2008). It is improbable that this
mechanism is responsible for stranding
events or traumas associated with
beaked whale strandings because both
the degree of supersaturation and
exposure levels observed to cause
microbubble destabilization are unlikely
to occur, either alone or in concert.
Yet another hypothesis
(decompression sickness) has
speculated that rapid ascent to the
surface following exposure to a startling
sound might produce tissue gas
saturation sufficient for the evolution of
nitrogen bubbles (Jepson et al., 2003;
Fernandez et al., 2005; Ferna´ndez et al.,
2012). In this scenario, the rate of ascent
would need to be sufficiently rapid to
compromise behavioral or physiological
protections against nitrogen bubble
formation. Alternatively, Tyack et al.
(2006) studied the deep diving behavior
of beaked whales and concluded that:
‘‘Using current models of breath-hold
diving, we infer that their natural diving
behavior is inconsistent with known
problems of acute nitrogen
supersaturation and embolism.’’
Collectively, these hypotheses can be
referred to as ‘‘hypotheses of
acoustically mediated bubble growth.’’
Although theoretical predictions
suggest the possibility for acoustically
mediated bubble growth, there is
considerable disagreement among
scientists as to its likelihood (Piantadosi
and Thalmann, 2004; Evans and Miller,
2003; Cox et al., 2006; Rommel et al.,
2006). Crum and Mao (1996)
hypothesized that received levels would
have to exceed 190 dB in order for there
to be the possibility of significant
bubble growth due to supersaturation of
PO 00000
Frm 00019
Fmt 4701
Sfmt 4702
49673
gases in the blood (i.e., rectified
diffusion). Work conducted by Crum et
al. (2005) demonstrated the possibility
of rectified diffusion for short duration
signals, but at SELs and tissue
saturation levels that are highly
improbable to occur in diving marine
mammals. To date, energy levels (ELs)
predicted to cause in vivo bubble
formation within diving cetaceans have
not been evaluated (NOAA, 2002b).
Jepson et al. (2003, 2005) and Fernandez
et al. (2004, 2005, 2012) concluded that
in vivo bubble formation, which may be
exacerbated by deep, long-duration,
repetitive dives may explain why
beaked whales appear to be relatively
vulnerable to MF/HF sonar exposures. It
has also been argued that traumas from
some beaked whale strandings are
consistent with gas emboli and bubbleinduced tissue separations (Jepson et
al., 2003); however, there is no
conclusive evidence of this (Rommel et
al., 2006). Based on examination of
sonar-associated strandings, Bernaldo
de Quiros et al. (2019) list diagnostic
features, the presence of all of which
suggest gas and fat embolic syndrome
for beaked whales stranded in
association with sonar exposure.
As described in additional detail in
the Nitrogen Decompression subsection
of the 2020 GOA DSEIS/OEIS, marine
mammals generally are thought to deal
with nitrogen loads in their blood and
other tissues, caused by gas exchange
from the lungs under conditions of high
ambient pressure during diving, through
anatomical, behavioral, and
physiological adaptations (Hooker et al.,
2012). Although not a direct injury,
variations in marine mammal diving
behavior or avoidance responses have
been hypothesized to result in nitrogen
off-gassing in super-saturated tissues,
possibly to the point of deleterious
vascular and tissue bubble formation
(Hooker et al., 2012; Jepson et al., 2003;
Saunders et al., 2008) with resulting
symptoms similar to decompression
sickness, however the process is still not
well understood.
Fahlman et al. (2021) explained how
stress can have a critical role in causing
the gas emboli present in stranded
cetaceans. The authors review
decompression theory and the
mechanisms dolphins have evolved to
prevent high N2 levels and gas emboli
in normal conditions, and describe how,
in times of high stress, the selective gas
exchange hypothesis states that this
mechanism can break down. In
addition, circulating microparticles may
be a useful biomarker for decompression
stress in cetaceans. Velazquez-Wallraf et
al. (2021) found that individual
variation also has an essential role in
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49674
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
this condition. To validate
decompression sickness observations in
certain stranded cetaceans found
coincident with naval activities, the
study used rabbits as an experimental
pathological model and found that
rabbit mortalities during or immediately
following decompression showed
systematically distributed gas bubbles
(microscopic and macroscopic), as well
as emphysema and hemorrhages in
multiple organs, similar to observations
in the stranded cetacean mortalities.
Similar findings were not found in
almost half the rabbits that survived at
least one hour after decompression,
revealing individual variation has an
essential role in this condition.
In 2009, Hooker et al. tested two
mathematical models to predict blood
and tissue tension N2 (PN2) using field
data from three beaked whale species:
northern bottlenose whales, Cuvier’s
beaked whales, and Blainville’s beaked
whales. The researchers aimed to
determine if physiology (body mass,
diving lung volume, and dive response)
or dive behavior (dive depth and
duration, changes in ascent rate, and
diel behavior) would lead to differences
in PN2 levels and thereby decompression
sickness risk between species. In their
study, they compared results for
previously published time depth
recorder data (Hooker and Baird, 1999;
Baird et al., 2006, 2008) from Cuvier’s
beaked whale, Blainville’s beaked
whale, and northern bottlenose whale.
They reported that diving lung volume
and extent of the dive response had a
large effect on end-dive PN2. Also,
results showed that dive profiles had a
larger influence on end-dive PN2 than
body mass differences between species.
Despite diel changes (i.e., variation that
occurs regularly every day or most days)
in dive behavior, PN2 levels showed no
consistent trend. Model output
suggested that all three species live with
tissue PN2 levels that would cause a
significant proportion of decompression
sickness cases in terrestrial mammals.
The authors concluded that the dive
behavior of Cuvier’s beaked whale was
different from both Blainville’s beaked
whale and northern bottlenose whale,
and resulted in higher predicted tissue
and blood N2 levels (Hooker et al.,
2009). They also suggested that the
prevalence of Cuvier’s beaked whales
stranding after naval sonar exercises
could be explained by either a higher
abundance of this species in the affected
areas or by possible species differences
in behavior and/or physiology related to
MF active sonar (Hooker et al., 2009).
Bernaldo de Quiros et al. (2012)
showed that, among stranded whales,
deep diving species of whales had
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
higher abundances of gas bubbles
compared to shallow diving species.
Kvadsheim et al. (2012) estimated blood
and tissue PN2 levels in species
representing shallow, intermediate, and
deep diving cetaceans following
behavioral responses to sonar and their
comparisons found that deep diving
species had higher end-dive blood and
tissue N2 levels, indicating a higher risk
of developing gas bubble emboli
compared with shallow diving species.
Fahlmann et al. (2014) evaluated dive
data recorded from sperm, killer, longfinned pilot, Blainville’s beaked and
Cuvier’s beaked whales before and
during exposure to low-frequency (1–2
kHz), as defined by the authors, and
mid-frequency (2–7 kHz) active sonar in
an attempt to determine if either
differences in dive behavior or
physiological responses to sonar are
plausible risk factors for bubble
formation. The authors suggested that
CO2 may initiate bubble formation and
growth, while elevated levels of N2 may
be important for continued bubble
growth. The authors also suggest that if
CO2 plays an important role in bubble
formation, a cetacean escaping a sound
source may experience increased
metabolic rate, CO2 production, and
alteration in cardiac output, which
could increase risk of gas bubble emboli.
However, as discussed in Kvadsheim et
al. (2012), the actual observed
behavioral responses to sonar from the
species in their study (sperm, killer,
long-finned pilot, Blainville’s beaked,
and Cuvier’s beaked whales) did not
imply any significantly increased risk of
decompression sickness due to high
levels of N2. Therefore, further
information is needed to understand the
relationship between exposure to
stimuli, behavioral response (discussed
in more detail below), elevated N2
levels, and gas bubble emboli in marine
mammals. The hypotheses for gas
bubble formation related to beaked
whale strandings is that beaked whales
potentially have strong avoidance
responses to MF active sonars because
they sound similar to their main
predator, the killer whale (Cox et al.,
2006; Southall et al., 2007; Zimmer and
Tyack, 2007; Baird et al., 2008; Hooker
et al., 2009). Further investigation is
needed to assess the potential validity of
these hypotheses.
To summarize, while there are several
hypotheses, there is little data directly
connecting intense, anthropogenic
underwater sounds with non-auditory
physical effects in marine mammals.
The available data do not support
identification of a specific exposure
level above which non-auditory effects
PO 00000
Frm 00020
Fmt 4701
Sfmt 4702
can be expected (Southall et al., 2007)
or any meaningful quantitative
predictions of the numbers (if any) of
marine mammals that might be affected
in these ways. In addition, such effects,
if they occur at all, would be expected
to be limited to situations where marine
mammals are exposed to high powered
sounds at very close range over a
prolonged period of time, which is not
expected to occur based on the speed of
the vessels operating sonar in
combination with the speed and
behavior of marine mammals in the
vicinity of sonar.
Injury Due to Sonar-Induced Acoustic
Resonance
An object exposed to its resonant
frequency will tend to amplify its
vibration at that frequency, a
phenomenon called acoustic resonance.
Acoustic resonance has been proposed
as a potential mechanism by which a
sonar or sources with similar operating
characteristics could damage tissues of
marine mammals. In 2002, NMFS
convened a panel of government and
private scientists to investigate the
potential for acoustic resonance to occur
in marine mammals (NOAA, 2002).
They modeled and evaluated the
likelihood that Navy mid-frequency
sonar (2–10 kHz) caused resonance
effects in beaked whales that eventually
led to their stranding. The workshop
participants concluded that resonance
in air-filled structures was not likely to
have played a primary role in the
Bahamas stranding in 2000. They listed
several reasons supporting this finding
including (among others): tissue
displacements at resonance are
estimated to be too small to cause tissue
damage; tissue-lined air spaces most
susceptible to resonance are too large in
marine mammals to have resonant
frequencies in the ranges used by midfrequency or low-frequency sonar; lung
resonant frequencies increase with
depth, and tissue displacements
decrease with depth so if resonance is
more likely to be caused at depth it is
also less likely to have an affect there;
and lung tissue damage has not been
observed in any mass, multi-species
stranding of beaked whales. The
frequency at which resonance was
predicted to occur in the animals’ lungs
was 50 Hz, well below the frequencies
used by the mid-frequency sonar
systems associated with the Bahamas
event. The workshop participants
focused on the March 2000 stranding of
beaked whales in the Bahamas as highquality data were available, but the
workshop report notes that the results
apply to other sonar-related stranding
events. For the reasons given by the
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
2002 workshop participants, we do not
anticipate injury due to sonar-induced
acoustic resonance from the Navy’s
planned activities.
Physiological Stress
There is growing interest in
monitoring and assessing the impacts of
stress responses to sound in marine
animals. Classic stress responses begin
when an animal’s central nervous
system perceives a potential threat to its
homeostasis. That perception triggers
stress responses regardless of whether a
stimulus actually threatens the animal;
the mere perception of a threat is
sufficient to trigger a stress response
(Moberg, 2000; Sapolsky et al., 2005;
Seyle, 1950). Once an animal’s central
nervous system perceives a threat, it
mounts a biological response or defense
that consists of a combination of the
four general biological defense
responses: behavioral responses,
autonomic nervous system responses,
neuroendocrine responses, or immune
responses.
According to Moberg (2000), in the
case of many stressors, an animal’s first
and sometimes most economical (in
terms of biotic costs) response is
behavioral avoidance of the potential
stressor or avoidance of continued
exposure to a stressor. An animal’s
second line of defense to stressors
involves the sympathetic part of the
autonomic nervous system and the
classical ‘‘fight or flight’’ response
which includes the cardiovascular
system, the gastrointestinal system, the
exocrine glands, and the adrenal
medulla to produce changes in heart
rate, blood pressure, and gastrointestinal
activity that humans commonly
associate with ‘‘stress.’’ These responses
have a relatively short duration and may
or may not have significant long-term
effect on an animal’s welfare.
An animal’s third line of defense to
stressors involves its neuroendocrine
systems or sympathetic nervous
systems; the system that has received
the most study has been the
hypothalmus-pituitary-adrenal system
(also known as the HPA axis in
mammals or the hypothalamuspituitary-interrenal axis in fish and
some reptiles). Unlike stress responses
associated with the autonomic nervous
system, virtually all neuro-endocrine
functions that are affected by stress—
including immune competence,
reproduction, metabolism, and
behavior—are regulated by pituitary
hormones. Stress-induced changes in
the secretion of pituitary hormones have
been implicated in failed reproduction
(Moberg, 1987; Rivier and Rivest, 1991),
altered metabolism (Elasser et al., 2000),
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
reduced immune competence (Blecha,
2000), and behavioral disturbance
(Moberg, 1987; Blecha, 2000). Increases
in the circulation of glucocorticosteroids
(cortisol, corticosterone, and
aldosterone in marine mammals; see
Romano et al., 2004) have been equated
with stress for many years.
The primary distinction between
stress (which is adaptive and does not
normally place an animal at risk) and
distress is the biotic cost of the
response. During a stress response, an
animal uses glycogen stores that can be
quickly replenished once the stress is
alleviated. In such circumstances, the
cost of the stress response would not
pose serious fitness consequences.
However, when an animal does not have
sufficient energy reserves to satisfy the
energetic costs of a stress response,
energy resources must be diverted from
other biotic functions, which impairs
those functions that experience the
diversion. For example, when a stress
response diverts energy away from
growth in young animals, those animals
may experience stunted growth. When a
stress response diverts energy from a
fetus, an animal’s reproductive success
and its fitness will suffer. In these cases,
the animals will have entered a prepathological or pathological state which
is called ‘‘distress’’ (Seyle, 1950) or
‘‘allostatic loading’’ (McEwen and
Wingfield, 2003). This pathological state
of distress will last until the animal
replenishes its energetic reserves
sufficiently to restore normal function.
Note that these examples involved a
long-term (days or weeks) stress
response exposure to stimuli.
Relationships between these
physiological mechanisms, animal
behavior, and the costs of stress
responses are well-studied through
controlled experiments in both
laboratory and free-ranging animals (for
examples see, Holberton et al., 1996;
Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al.,
2005; Reneerkens et al., 2002;
Thompson and Hamer, 2000). However,
it should be noted (and as is described
in additional detail in the 2020 GOA
DSEIS/OEIS) that our understanding of
the functions of various stress hormones
(for example, cortisol), is based largely
upon observations of the stress response
in terrestrial mammals. Atkinson et al.,
2015 note that the endocrine response of
marine mammals to stress may not be
the same as that of terrestrial mammals
because of the selective pressures
marine mammals faced during their
evolution in an ocean environment. For
example, due to the necessity of breathholding while diving and foraging at
depth, the physiological role of
PO 00000
Frm 00021
Fmt 4701
Sfmt 4702
49675
epinephrine and norepinephrine (the
catecholamines) in marine mammals
might be different than in other
mammals.
Marine mammals naturally
experience stressors within their
environment and as part of their life
histories. Changing weather and ocean
conditions, exposure to disease and
naturally occurring toxins, lack of prey
availability, and interactions with
predators all contribute to the stress a
marine mammal experiences (Atkinson
et al., 2015). Breeding cycles, periods of
fasting, and social interactions with
members of the same species are also
stressors, although they are natural
components of an animal’s life history.
Anthropogenic activities have the
potential to provide additional stressors
beyond those that occur naturally (Fair
et al., 2014; Meissner et al., 2015;
Rolland et al., 2012). Anthropogenic
stressors potentially include such things
as fishery interactions, pollution,
tourism, and ocean noise.
Acoustically induced stress in marine
mammals is not well understood. There
are ongoing efforts to improve our
understanding of how stressors impact
marine mammal populations (e.g., King
et al., 2015; New et al., 2013a; New et
al., 2013b; Pirotta et al., 2015a),
however little data exist on the
consequences of sound-induced stress
response (acute or chronic). Factors
potentially affecting a marine mammal’s
response to a stressor include the
individual’s life history stage, sex, age,
reproductive status, overall
physiological and behavioral plasticity,
and whether they are naı¨ve or
experienced with the sound (e.g., prior
experience with a stressor may result in
a reduced response due to habituation
(Finneran and Branstetter, 2013; St.
Aubin and Dierauf, 2001). Stress
responses due to exposure to
anthropogenic sounds or other stressors
and their effects on marine mammals
have been reviewed (Fair and Becker,
2000; Romano et al., 2002b) and, more
rarely, studied in wild populations (e.g.,
Romano et al., 2002a). For example,
Rolland et al. (2012) found that noise
reduction from reduced ship traffic in
the Bay of Fundy was associated with
decreased stress in North Atlantic right
whales. These and other studies lead to
a reasonable expectation that some
marine mammals will experience
physiological stress responses upon
exposure to acoustic stressors and that
it is possible that some of these would
be classified as ‘‘distress.’’ In addition,
any animal experiencing TTS would
likely also experience stress responses
(NRC, 2003).
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49676
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
Other research has also investigated
the impact from vessels (both whalewatching and general vessel traffic
noise), and demonstrated impacts do
occur (Bain, 2002; Erbe, 2002; Lusseau,
2006; Williams et al., 2006; Williams et
al., 2009; Noren et al., 2009; Read et al.,
2014; Rolland et al., 2012; Skarke et al.,
2014; Williams et al., 2013; Williams et
al., 2014a; Williams et al., 2014b; Pirotta
et al., 2015b). This body of research has
generally investigated impacts
associated with the presence of chronic
stressors, which differ significantly from
the proposed Navy training activities in
the GOA Study Area. For example, in an
analysis of energy costs to killer whales,
Williams et al. (2009) suggested that
whale-watching in Canada’s Johnstone
Strait resulted in lost feeding
opportunities due to vessel disturbance,
which could carry higher costs than
other measures of behavioral change
might suggest. Ayres et al. (2012)
reported on research in the Salish Sea
(Washington state) involving the
measurement of southern resident killer
whale fecal hormones to assess two
potential threats to the species recovery:
lack of prey (salmon) and impacts to
behavior from vessel traffic. Ayres et al.
(2012) suggested that the lack of prey
overshadowed any population-level
physiological impacts on southern
resident killer whales from vessel
traffic. In a conceptual model developed
by the Population Consequences of
Acoustic Disturbance (PCAD) working
group, serum hormones were identified
as possible indicators of behavioral
effects that are translated into altered
rates of reproduction and mortality
(NRC, 2005). The Office of Naval
Research hosted a workshop (Effects of
Stress on Marine Mammals Exposed to
Sound) in 2009 that focused on this
topic (ONR, 2009). Ultimately, the
PCAD working group issued a report
(Cochrem, 2014) that summarized
information compiled from 239 papers
or book chapters relating to stress in
marine mammals and concluded that
stress responses can last from minutes
to hours and, while we typically focus
on adverse stress responses, stress
response is part of a natural process to
help animals adjust to changes in their
environment and can also be either
neutral or beneficial.
Most sound-induced stress response
studies in marine mammals have
focused on acute responses to sound
either by measuring catecholamines or
by measuring heart rate as an assumed
proxy for an acute stress response.
Belugas demonstrated no catecholamine
response to the playback of oil drilling
sounds (Thomas et al., 1990) but
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
showed a small but statistically
significant increase in catecholamines
following exposure to impulsive sounds
produced from a seismic water gun
(Romano et al., 2004). A bottlenose
dolphin exposed to the same seismic
water gun signals did not demonstrate a
catecholamine response, but did
demonstrate a statistically significant
elevation in aldosterone (Romano et al.,
2004), albeit the increase was within the
normal daily variation observed in this
species (St. Aubin et al., 1996).
Increases in heart rate were observed in
bottlenose dolphins to which known
calls of other dolphins were played,
although no increase in heart rate was
observed when background tank noise
was played back (Miksis et al., 2001).
Unfortunately, in this study, it cannot
be determined whether the increase in
heart rate was due to stress or an
anticipation of being reunited with the
dolphin to which the vocalization
belonged. Similarly, a young beluga’s
heart rate was observed to increase
during exposure to noise, with increases
dependent upon the frequency band of
noise and duration of exposure, and
with a sharp decrease to normal or
below normal levels upon cessation of
the exposure (Lyamin et al., 2011).
Spectral analysis of heart rate variability
corroborated direct measures of heart
rate (Bakhchina et al., 2017). This
response might have been in part due to
the conditions during testing, the young
age of the animal, and the novelty of the
exposure; a year later the exposure was
repeated at a slightly higher received
level and there was no heart rate
response, indicating the beluga whale
may have acclimated to the noise
exposure. Kvadsheim et al. (2010)
measured the heart rate of captive
hooded seals during exposure to sonar
signals and found an increase in the
heart rate of the seals during exposure
periods versus control periods when the
animals were at the surface. When the
animals dove, the normal dive-related
bradycardia (decrease in heart rate) was
not impacted by the sonar exposure.
Elmegaard et al. (2021) found that sonar
sweeps did not elicit a startle response
in captive harbor porpoises, but initial
exposures induced bradycardia,
whereas impulse exposures induced
startle responses without a change in
heart rate. The authors suggested that
the parasympathetic cardiac dive
response may override any transient
sympathetic response, or that diving
mammals may not have the cardiac
startle response seen in terrestrial
mammals in order to maintain volitional
cardiovascular control at depth.
Similarly, Thompson et al. (1998)
PO 00000
Frm 00022
Fmt 4701
Sfmt 4702
observed a rapid but short-lived
decrease in heart rates in harbor and
grey seals exposed to seismic air guns
(cited in Gordon et al., 2003). Williams
et al. (2017) monitored the heart rates of
narwhals released from capture and
found that a profound dive bradycardia
persisted, even though exercise effort
increased dramatically as part of their
escape response following release. Thus,
although some limited evidence
suggests that tachycardia might occur as
part of the acute stress response of
animals that are at the surface, the dive
bradycardia persists during diving and
might be enhanced in response to an
acute stressor. Yang et al. (2021)
measured cortisol concentrations in two
bottlenose dolphins and found
significantly higher concentrations after
exposure to 140 dB re 1 mPa impulsive
noise playbacks. Two out of six tested
indicators of immune system function
underwent acoustic dose-dependent
changes, suggesting that repeated
exposures or sustained stress response
to impulsive sounds may increase an
affected individual’s susceptibility to
pathogens. However, exposing dolphins
to a different acoustic stressor yielded
contrasting results. Houser et al. (2020)
measured cortisol and epinephrine
obtained from 30 bottlenose dolphins
exposed to simulated U.S. Navy midfrequency sonar and found no
correlation between SPL and stress
hormone levels. In the same experiment
(Houser et al., 2013b), behavioral
responses were shown to increase in
severity with increasing received SPLs.
These results suggest that behavioral
reactions to sonar signals are not
necessarily indicative of a hormonal
stress response. Houser et al. (2020)
notes that additional research is needed
to determine the relationship between
behavioral responses and physiological
responses.
Despite the limited amount of data
available on sound-induced stress
responses for marine mammals exposed
to anthropogenic sounds, studies of
other marine animals and terrestrial
animals would also lead us to expect
that some marine mammals experience
physiological stress responses and,
perhaps, physiological responses that
would be classified as ‘‘distress’’ upon
exposure to high-frequency, midfrequency, and low-frequency sounds.
For example, Jansen (1998) reported on
the relationship between acoustic
exposures and physiological responses
that are indicative of stress responses in
humans (e.g., elevated respiration and
increased heart rates). Jones (1998)
reported on reductions in human
performance when faced with acute,
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
repetitive exposures to acoustic
disturbance. Trimper et al. (1998)
reported on the physiological stress
responses of osprey to low-level aircraft
noise while Krausman et al. (2004)
reported on the auditory and
physiological stress responses of
endangered Sonoran pronghorn to
military overflights. However, take due
to aircraft noise is not anticipated as a
result of the Navy’s activities. Smith et
al. (2004a, 2004b) identified noiseinduced physiological transient stress
responses in hearing-specialist fish (i.e.,
goldfish) that accompanied short- and
long-term hearing losses. Welch and
Welch (1970) reported physiological
and behavioral stress responses that
accompanied damage to the inner ears
of fish and several mammals.
Auditory Masking
Sound can disrupt behavior through
masking, or interfering with, an animal’s
ability to detect, recognize, or
discriminate between acoustic signals of
interest (e.g., those used for intraspecific
communication and social interactions,
prey detection, predator avoidance, or
navigation) (Richardson et al., 1995;
Erbe and Farmer, 2000; Tyack, 2000;
Erbe et al., 2016). Masking occurs when
the receipt of a sound is interfered with
by another coincident sound at similar
frequencies and at similar or higher
intensity, and may occur whether the
sound is natural (e.g., snapping shrimp,
wind, waves, precipitation) or
anthropogenic (e.g., shipping, sonar,
seismic exploration) in origin. As
described in detail in the 2020 GOA
DSEIS/OEIS, the ability of a noise
source to mask biologically important
sounds depends on the characteristics of
both the noise source and the signal of
interest (e.g., signal-to-noise ratio,
temporal variability, direction), in
relation to each other and to an animal’s
hearing abilities (e.g., sensitivity,
frequency range, critical ratios,
frequency discrimination, directional
discrimination, age, or TTS hearing
loss), and existing ambient noise and
propagation conditions. Masking these
acoustic signals can disturb the behavior
of individual animals, groups of
animals, or entire populations. Masking
can lead to behavioral changes
including vocal changes (e.g., Lombard
effect, increasing amplitude, or
changing frequency), cessation of
foraging, and leaving an area, to both
signalers and receivers, in an attempt to
compensate for noise levels (Erbe et al.,
2016).
In humans, significant masking of
tonal signals occurs as a result of
exposure to noise in a narrow band of
similar frequencies. As the sound level
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
increases, though, the detection of
frequencies above those of the masking
stimulus decreases also. This principle
is expected to apply to marine mammals
as well because of common
biomechanical cochlear properties
across taxa.
Under certain circumstances, marine
mammals experiencing significant
masking could also be impaired from
maximizing their performance fitness in
survival and reproduction. Therefore,
when the coincident (masking) sound is
man-made, it may be considered
harassment when disrupting natural
behavioral patterns to the point where
the behavior is abandoned or
significantly altered. It is important to
distinguish TTS and PTS, which persist
after the sound exposure, from masking,
which only occurs during the sound
exposure. Because masking (without
resulting in threshold shift) is not
associated with abnormal physiological
function, it is not considered a
physiological effect, but rather a
potential behavioral effect.
Richardson et al. (1995b) argued that
the maximum radius of influence of an
industrial noise (including broadband
low-frequency sound transmission) on a
marine mammal is the distance from the
source to the point at which the noise
can barely be heard. This range is
determined by either the hearing
sensitivity (including critical ratios, or
the lowest signal-to-noise ratio in which
animals can detect a signal, Finneran
and Branstetter, 2013; Johnson et al.,
1989; Southall et al., 2000) of the animal
or the background noise level present.
Industrial masking is most likely to
affect some species’ ability to detect
communication calls and natural
sounds (i.e., surf noise, prey noise, etc.;
Richardson et al., 1995).
The frequency range of the potentially
masking sound is important in
determining any potential behavioral
impacts. For example, low-frequency
signals may have less effect on highfrequency echolocation sounds
produced by odontocetes but are more
likely to affect detection of mysticete
communication calls and other
potentially important natural sounds
such as those produced by surf and
some prey species. The masking of
communication signals by
anthropogenic noise may be considered
as a reduction in the communication
space of animals (e.g., Clark et al., 2009;
Matthews et al., 2016) and may result in
energetic or other costs as animals
change their vocalization behavior (e.g.,
Miller et al., 2000; Foote et al., 2004;
Parks et al., 2007; Di Iorio and Clark,
2009; Holt et al., 2009). Masking can be
reduced in situations where the signal
PO 00000
Frm 00023
Fmt 4701
Sfmt 4702
49677
and noise come from different
directions (Richardson et al., 1995),
through amplitude modulation of the
signal, or through other compensatory
behaviors (Houser and Moore, 2014).
Masking can be tested directly in
captive species (e.g., Erbe, 2008), but in
wild populations it must be either
modeled or inferred from evidence of
masking compensation. There are few
studies addressing real-world masking
sounds likely to be experienced by
marine mammals in the wild (e.g.,
Branstetter et al., 2013).
The echolocation calls of toothed
whales are subject to masking by highfrequency sound. Human data indicate
low-frequency sound can mask highfrequency sounds (i.e., upward
masking). Studies on captive
odontocetes by Au et al. (1974, 1985,
1993) indicate that some species may
use various processes to reduce masking
effects (e.g., adjustments in echolocation
call intensity or frequency as a function
of background noise conditions). There
is also evidence that the directional
hearing abilities of odontocetes are
useful in reducing masking at the highfrequencies these cetaceans use to
echolocate, but not at the low-tomoderate frequencies they use to
communicate (Zaitseva et al., 1980). A
study by Nachtigall and Supin (2018)
showed that false killer whales adjust
their hearing to compensate for ambient
sounds and the intensity of returning
echolocation signals.
Impacts on signal detection, measured
by masked detection thresholds, are not
the only important factors to address
when considering the potential effects
of masking. As marine mammals use
sound to recognize conspecifics, prey,
predators, or other biologically
significant sources (Branstetter et al.,
2016), it is also important to understand
the impacts of masked recognition
thresholds (often called ‘‘informational
masking’’). Branstetter et al., 2016
measured masked recognition
thresholds for whistle-like sounds of
bottlenose dolphins and observed that
they are approximately 4 dB above
detection thresholds (energetic masking)
for the same signals. Reduced ability to
recognize a conspecific call or the
acoustic signature of a predator could
have severe negative impacts.
Branstetter et al., 2016 observed that if
‘‘quality communication’’ is set at 90
percent recognition the output of
communication space models (which
are based on 50 percent detection)
would likely result in a significant
decrease in communication range.
As marine mammals use sound to
recognize predators (Allen et al., 2014;
Cummings and Thompson, 1971; Cure´
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49678
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
et al., 2015; Fish and Vania, 1971), the
presence of masking noise may also
prevent marine mammals from
responding to acoustic cues produced
by their predators, particularly if it
occurs in the same frequency band. For
example, harbor seals that reside in the
coastal waters off British Columbia are
frequently targeted by mammal-eating
killer whales. The seals acoustically
discriminate between the calls of
mammal-eating and fish-eating killer
whales (Deecke et al., 2002), a capability
that should increase survivorship while
reducing the energy required to attend
to all killer whale calls. Similarly,
sperm whales (Cure´ et al., 2016;
Isojunno et al., 2016), long-finned pilot
whales (Visser et al., 2016), and
humpback whales (Cure´ et al., 2015)
changed their behavior in response to
killer whale vocalization playbacks;
these findings indicate that some
recognition of predator cues could be
missed if the killer whale vocalizations
were masked. The potential effects of
masked predator acoustic cues depends
on the duration of the masking noise
and the likelihood of a marine mammal
encountering a predator during the time
that detection and recognition of
predator cues are impeded.
Redundancy and context can also
facilitate detection of weak signals.
These phenomena may help marine
mammals detect weak sounds in the
presence of natural or manmade noise.
Most masking studies in marine
mammals present the test signal and the
masking noise from the same direction.
The dominant background noise may be
highly directional if it comes from a
particular anthropogenic source such as
a ship or industrial site. Directional
hearing may significantly reduce the
masking effects of these sounds by
improving the effective signal-to-noise
ratio.
Masking affects both senders and
receivers of acoustic signals and can
potentially have long-term chronic
effects on marine mammals at the
population level as well as at the
individual level. Low-frequency
ambient sound levels have increased by
as much as 20 dB (more than three times
in terms of SPL) in the world’s ocean
from pre-industrial periods, with most
of the increase from distant commercial
shipping (Hildebrand, 2009). All
anthropogenic sound sources, but
especially chronic and lower-frequency
signals (e.g., from commercial vessel
traffic), contribute to elevated ambient
sound levels, thus intensifying masking.
Impaired Communication
In addition to making it more difficult
for animals to perceive and recognize
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
acoustic cues in their environment,
anthropogenic sound presents separate
challenges for animals that are
vocalizing. When they vocalize, animals
are aware of environmental conditions
that affect the ‘‘active space’’ (or
communication space) of their
vocalizations, which is the maximum
area within which their vocalizations
can be detected before it drops to the
level of ambient noise (Brenowitz, 2004;
Brumm et al., 2004; Lohr et al., 2003).
Animals are also aware of
environmental conditions that affect
whether listeners can discriminate and
recognize their vocalizations from other
sounds, which is more important than
simply detecting that a vocalization is
occurring (Brenowitz, 1982; Brumm et
al., 2004; Dooling, 2004, Marten and
Marler, 1977; Patricelli et al., 2006).
Anthropogenic sounds that reduce the
signal-to-noise ratio of animal
vocalizations, increase the masked
auditory thresholds of animals listening
for such vocalizations, or reduce the
active space of an animal’s
vocalizations, impair communication
between animals. Most species that
vocalize have evolved with an ability to
make adjustments to their vocalizations
to increase the signal-to-noise ratio,
active space, and recognizability/
distinguishability of their vocalizations
in the face of temporary changes in
background noise (Brumm et al., 2004;
Patricelli et al., 2006). Vocalizing
animals can make adjustments to
vocalization characteristics such as the
frequency structure, amplitude,
temporal structure, and temporal
delivery (repetition rate), or may cease
to vocalize.
Many animals will combine several of
these strategies to compensate for high
levels of background noise. Although
the fitness consequences of vocal
adjustments are not directly known in
all instances, like most other trade-offs
animals must make, some of these
strategies probably come at a cost
(Patricelli et al., 2006). Shifting songs
and calls to higher frequencies may also
impose energetic costs (Lambrechts,
1996). For example, in birds, vocalizing
more loudly in noisy environments may
have energetic costs that decrease the
net benefits of vocal adjustment and
alter a bird’s energy budget (Brumm,
2004; Wood and Yezerinac, 2006).
Marine mammals are also known to
make vocal changes in response to
anthropogenic noise. In cetaceans,
vocalization changes have been reported
from exposure to anthropogenic noise
sources such as sonar, vessel noise, and
seismic surveying (see the following for
examples: Gordon et al., 2003; Di Iorio
and Clark, 2010; Hatch et al., 2012; Holt
PO 00000
Frm 00024
Fmt 4701
Sfmt 4702
et al., 2008; Holt et al., 2011; Lesage et
al., 1999; McDonald et al., 2009; Parks
et al., 2007, Risch et al., 2012, Rolland
et al., 2012), as well as changes in the
natural acoustic environment (Caruso et
al., 2020; Dunlop et al., 2014; Helble et
al., 2020). Vocal changes can be
temporary, or can be persistent. For
example, model simulation suggests that
the increase in starting frequency for the
North Atlantic right whale upcall over
the last 50 years resulted in increased
detection ranges between right whales.
The frequency shift, coupled with an
increase in call intensity by 20 dB, led
to a call detectability range of less than
3 km to over 9 km (Tennessen and
Parks, 2016). Holt et al. (2008) measured
killer whale call source levels and
background noise levels in the one to 40
kHz band and reported that the whales
increased their call source levels by one
dB SPL for every one dB SPL increase
in background noise level. Similarly,
another study on St. Lawrence River
belugas reported a similar rate of
increase in vocalization activity in
response to passing vessels (Scheifele et
al., 2005). Di Iorio and Clark (2010)
showed that blue whale calling rates
vary in association with seismic sparker
survey activity, with whales calling
more on days with surveys than on days
without surveys. They suggested that
the whales called more during seismic
survey periods as a way to compensate
for the elevated noise conditions.
In some cases, these vocal changes
may have fitness consequences, such as
an increase in metabolic rates and
oxygen consumption, as observed in
bottlenose dolphins when increasing
their call amplitude (Holt et al., 2015).
A switch from vocal communication to
physical, surface-generated sounds such
as pectoral fin slapping or breaching
was observed for humpback whales in
the presence of increasing natural
background noise levels, indicating that
adaptations to masking may also move
beyond vocal modifications (Dunlop et
al., 2010).
While these changes all represent
possible tactics by the sound-producing
animal to reduce the impact of masking,
the receiving animal can also reduce
masking by using active listening
strategies such as orienting to the sound
source, moving to a quieter location, or
reducing self-noise from hydrodynamic
flow by remaining still. The temporal
structure of noise (e.g., amplitude
modulation) may also provide a
considerable release from masking
through comodulation masking release
(a reduction of masking that occurs
when broadband noise, with a
frequency spectrum wider than an
animal’s auditory filter bandwidth at the
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
frequency of interest, is amplitude
modulated) (Branstetter and Finneran,
2008; Branstetter et al., 2013). Signal
type (e.g., whistles, burst-pulse, sonar
clicks) and spectral characteristics (e.g.,
frequency modulated with harmonics)
may further influence masked detection
thresholds (Branstetter et al., 2016;
Cunningham et al., 2014).
Masking Due to Sonar and Other
Transducers
The functional hearing ranges of
mysticetes, odontocetes, and pinnipeds
underwater overlap the frequencies of
the sonar sources used in the Navy’s
low-frequency active sonar (LFAS)/midfrequency active sonar (MFAS)/highfrequency active sonar (HFAS) training
exercises (though the Navy proposes no
LFAS use for the activities in this
rulemaking). Additionally, almost all
affected species’ vocal repertoires span
across the frequencies of these sonar
sources used by the Navy. The closer
the characteristics of the masking signal
to the signal of interest, the more likely
masking is to occur. Masking by midfrequency active sonar (MFAS) with
relatively low-duty cycles is not
anticipated (or would be of very short
duration) for most cetaceans as sonar
signals occur over a relatively short
duration and narrow bandwidth
(overlapping with only a small portion
of the hearing range). While dolphin
whistles and MFAS are similar in
frequency, masking is not anticipated
(or would be of very short duration) due
to the low-duty cycle of most sonars.
As described in the 2020 GOA DSEIS/
OEIS, newer high-duty cycle or
continuous active sonars have more
potential to mask vocalizations. These
sonars transmit more frequently (greater
than 80 percent duty cycle) than
traditional sonars, but at a substantially
lower source level. HFAS, such as
pingers that operate at higher repetition
rates (e.g., 2–10 kHz with harmonics up
to 19 kHz, 76 to 77 pings per minute)
(Culik et al., 2001), also operate at lower
source levels and have faster attenuation
rates due to the higher frequencies used.
These lower source levels limit the
range of impacts, however compared to
traditional sonar systems, individuals
close to the source are likely to
experience masking at longer time
scales. The frequency range at which
high-duty cycle systems operate
overlaps the vocalization frequency of
many mid-frequency cetaceans.
Continuous noise at the same frequency
of communicative vocalizations may
cause disruptions to communication,
social interactions, acoustically
mediated cooperative behaviors, and
important environmental cues. There is
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
also the potential for the mid-frequency
sonar signals to mask important
environmental cues (e.g., predator or
conspecific acoustic cues), possibly
affecting survivorship for targeted
animals. Masking due to high duty cycle
sonars is likely analogous to masking
produced by other continuous sources
(e.g., vessel noise and low-frequency
cetaceans), and would likely have
similar short-term consequences, though
longer in duration due to the duration
of the masking noise. A study by von
Benda-Beckmann et al. (2021) modeled
the effect of pulsed and continuous 1–
2 kHz active sonar on sperm whale
echolocation clicks, and found that the
presence of upper harmonics in the
sonar signal increased masking of clicks
produced in the search phase of foraging
compared to buzz clicks produced
during prey capture. Different levels of
sonar caused intermittent to continuous
masking (120 to 160 dB re 1 mPa2,
respectively), but varied based on click
level, whale orientation, and prey target
strength. Continuous active sonar
resulted in a greater percentage of time
that echolocation clicks were masked
compared to pulsed active sonar. Other
short-term consequences may include
changes to vocalization amplitude and
frequency (Brumm and Slabbekoorn,
2005; Hotchkin and Parks, 2013) and
behavioral impacts such as avoidance of
the area and interruptions to foraging or
other essential behaviors (Gordon et al.,
2003; Isojunno et al., 2021). Long-term
consequences could include changes to
vocal behavior and vocalization
structure (Foote et al., 2004; Parks et al.,
2007), abandonment of habitat if
masking occurs frequently enough to
significantly impair communication
(Brumm and Slabbekoorn, 2005), a
potential decrease in survivorship if
predator vocalizations are masked
(Brumm and Slabbekoorn, 2005), and a
potential decrease in recruitment if
masking interferes with reproductive
activities or mother-calf communication
(Gordon et al., 2003).
Masking Due to Vessel Noise
Masking is more likely to occur in the
presence of broadband, relatively
continuous noise sources such as
vessels. Several studies have shown
decreases in marine mammal
communication space and changes in
behavior as a result of the presence of
vessel noise. For example, right whales
were observed to shift the frequency
content of their calls upward while
reducing the rate of calling in areas of
increased anthropogenic noise (Parks et
al., 2007) as well as increasing the
amplitude (intensity) of their calls
(Parks, 2009; Parks et al., 2011). Fournet
PO 00000
Frm 00025
Fmt 4701
Sfmt 4702
49679
et al. (2018) observed that humpback
whales in Alaska responded to
increasing ambient sound levels (natural
and anthropogenic) by increasing the
source levels of their calls (non-song
vocalizations). Clark et al. (2009) also
observed that right whales
communication space decreased by up
to 84 percent in the presence of vessels
(Clark et al., 2009). Cholewiak et al.
(2018) also observed loss in
communication space in Stellwagen
National Marine Sanctuary for North
Atlantic right whales, fin whales, and
humpback whales with increased
ambient noise and shipping noise.
Gabriele et al. (2018) modeled the
effects of vessel traffic sound on
communication space in Glacier Bay
National Park in Alaska and found that
typical summer vessel traffic in the
National Park causes losses of
communication space to singing whales
(reduced by 13–28 percent), calling
whales (18–51 percent), and roaring
seals (32–61 percent), particularly
during daylight hours and even in the
absence of cruise ships. Dunlop (2019)
observed that an increase in vessel noise
reduced modelled communication space
and resulted in significant reduction in
group social interactions in Australian
humpback whales. However,
communication signal masking did not
fully explain this change in social
behavior in the model, indicating there
may also be an additional effect of the
physical presence of the vessel on social
behavior (Dunlop, 2019). Although
humpback whales off Australia did not
change the frequency or duration of
their vocalizations in the presence of
ship noise, their source levels were
lower than expected based on source
level changes to wind noise, potentially
indicating some signal masking
(Dunlop, 2016). Multiple delphinid
species have also been shown to
increase the minimum or maximum
frequencies of their whistles in the
presence of anthropogenic noise and
reduced communication space (for
examples see: Holt et al., 2008; Holt et
al., 2011; Gervaise et al., 2012; Williams
et al., 2013; Hermannsen et al., 2014;
Papale et al., 2015; Liu et al., 2017; Pine
et al., 2021).
Behavioral Response/Disturbance
Behavioral responses to sound are
highly variable and context-specific.
Many different variables can influence
an animal’s perception of and response
to (nature and magnitude) an acoustic
event. An animal’s prior experience
with a sound or sound source affects
whether it is less likely (habituation) or
more likely (sensitization) to respond to
certain sounds in the future (animals
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49680
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
can also be innately predisposed to
respond to certain sounds in certain
ways) (Southall et al., 2007). Related to
the sound itself, the perceived nearness
of the sound, bearing of the sound
(approaching vs. retreating), the
similarity of a sound to biologically
relevant sounds in the animal’s
environment (i.e., calls of predators,
prey, or conspecifics), and familiarity of
the sound may affect the way an animal
responds to the sound (Southall et al.,
2007; DeRuiter et al., 2013). Individuals
(of different age, gender, reproductive
status, etc.) among most populations
will have variable hearing capabilities,
and differing behavioral sensitivities to
sounds that will be affected by prior
conditioning, experience, and current
activities of those individuals. Often,
specific acoustic features of the sound
and contextual variables (i.e., proximity,
duration, or recurrence of the sound, or
the current behavior that the marine
mammal is engaged in or its prior
experience), as well as entirely separate
factors such as the physical presence of
a nearby vessel, may be more relevant
to the animal’s response than the
received level alone. For example,
Goldbogen et al. (2013) demonstrated
that individual behavioral state was
critically important in determining
response of blue whales to sonar, noting
that some individuals engaged in deep
(≤50 m) feeding behavior had greater
dive responses than those in shallow
feeding or non-feeding conditions. Some
blue whales in the Goldbogen et al.
(2013) study that were engaged in
shallow feeding behavior demonstrated
no clear changes in diving or movement
even when received levels (RLs) were
high (∼160 dB re: 1mPa) for exposures to
3–4 kHz sonar signals, while others
showed a clear response at exposures at
lower received levels of sonar and
pseudorandom noise.
Studies by DeRuiter et al. (2012)
indicate that variability of responses to
acoustic stimuli depends not only on
the species receiving the sound and the
sound source, but also on the social,
behavioral, or environmental contexts of
exposure. Another study by DeRuiter et
al. (2013) examined behavioral
responses of Cuvier’s beaked whales to
MF sonar and found that whales
responded strongly at low received
levels (RL of 89–127 dB re: 1mPa) by
ceasing normal fluking and
echolocation, swimming rapidly away,
and extending both dive duration and
subsequent non-foraging intervals when
the sound source was 3.4–9.5 km away.
Importantly, this study also showed that
whales exposed to a similar range of
received levels (78–106 dB re: 1 mPa)
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
from distant sonar exercises (118 km
away) did not elicit such responses,
suggesting that context may moderate
reactions.
Ellison et al. (2012) outlined an
approach to assessing the effects of
sound on marine mammals that
incorporates contextual-based factors.
The authors recommend considering not
just the received level of sound, but also
the activity the animal is engaged in at
the time the sound is received, the
nature and novelty of the sound (i.e., is
this a new sound from the animal’s
perspective), and the distance between
the sound source and the animal. They
submit that this ‘‘exposure context,’’ as
described, greatly influences the type of
behavioral response exhibited by the
animal. Forney et al. (2017) also point
out that an apparent lack of response
(e.g., no displacement or avoidance of a
sound source) may not necessarily mean
there is no cost to the individual or
population, as some resources or
habitats may be of such high value that
animals may choose to stay, even when
experiencing stress or hearing loss.
Forney et al. (2017) recommend
considering both the costs of remaining
in an area of noise exposure such as
TTS, PTS, or masking, which could lead
to an increased risk of predation or
other threats or a decreased capability to
forage, and the costs of displacement,
including potential increased risk of
vessel strike, increased risks of
predation or competition for resources,
or decreased habitat suitable for
foraging, resting, or socializing. This
sort of contextual information is
challenging to predict with accuracy for
ongoing activities that occur over large
spatial and temporal expanses.
However, distance is one contextual
factor for which data exist to
quantitatively inform a take estimate,
and the method for predicting Level B
harassment in this rule does consider
distance to the source. Other factors are
often considered qualitatively in the
analysis of the likely consequences of
sound exposure, where supporting
information is available.
Friedlaender et al. (2016) provided
the first integration of direct measures of
prey distribution and density variables
incorporated into across-individual
analyses of behavior responses of blue
whales to sonar, and demonstrated a
five-fold increase in the ability to
quantify variability in blue whale diving
behavior. These results illustrate that
responses evaluated without such
measurements for foraging animals may
be misleading, which again illustrates
the context-dependent nature of the
probability of response.
PO 00000
Frm 00026
Fmt 4701
Sfmt 4702
Exposure of marine mammals to
sound sources can result in, but is not
limited to, no response or any of the
following observable responses:
increased alertness; orientation or
attraction to a sound source; vocal
modifications; cessation of feeding;
cessation of social interaction; alteration
of movement or diving behavior; habitat
abandonment (temporary or permanent);
and, in severe cases, panic, flight,
stampede, or stranding, potentially
resulting in death (Southall et al., 2007;
Southall et al., 2021). A review of
marine mammal responses to
anthropogenic sound was first
conducted by Richardson (1995). More
recent reviews (Nowacek et al., 2007;
DeRuiter et al., 2012 and 2013; Ellison
et al., 2012; Gomez et al., 2016) address
studies conducted since 1995 and
focused on observations where the
received sound level of the exposed
marine mammal(s) was known or could
be estimated. Gomez et al. (2016)
conducted a review of the literature
considering the contextual information
of exposure in addition to received level
and found that higher received levels
were not always associated with more
severe behavioral responses and vice
versa. Southall et al. (2016) states that
results demonstrate that some
individuals of different species display
clear yet varied responses, some of
which have negative implications, while
others appear to tolerate high levels, and
that responses may not be fully
predictable with simple acoustic
exposure metrics (e.g., received sound
level). Rather, the authors state that
differences among species and
individuals along with contextual
aspects of exposure (e.g., behavioral
state) appear to affect response
probability.
Sperm whales were exposed to pulsed
active sonar (1–2 kHz) at moderate
source levels and high source levels, as
well as continuously active sonar at
moderate levels for which the summed
energy (SEL) equaled the summed
energy of the high source level pulsed
sonar (Isojunno et al., 2020). Foraging
behavior did not change during
exposures to moderate source level
sonar, but non-foraging behavior
increased during exposures to high
source level sonar and to the continuous
sonar, indicating that the energy of the
sound (the SEL) was a better predictor
of response than SPL. However, the time
of day of the exposure was also an
important covariate in determining the
amount of non-foraging behavior, as
were order effects (e.g. the SEL of the
previous exposure). Isojunno et al.
(2021) found that higher SELs reduced
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
sperm whale buzzing (i.e., foraging).
Duration of continuous sonar activity
also appears to impact sperm whale
displacement and foraging activity
(Stanistreet, 2022). During long bouts of
sonar lasting up to 13 consecutive
hours, occurring repeatedly over an 8
day naval exercise (median and
maximum SPL = 120 dB and 164 dB),
sperm whales substantially reduced
how often they produced clicks during
sonar, indicating a decrease or cessation
in foraging behavior. Few previous
studies have shown sustained changes
in sperm whales, but there was an
absence of sperm whale clicks for 6
consecutive days of sonar activity. Cure´
et al. (2021) also found that sperm
whales exposed to continuous and
pulsed active sonar were more likely to
produce low or medium severity
responses with higher cumulative SEL.
Specifically, the probability of observing
a low severity response increased to 0.5
at approximately 173 dB SEL and
observing a medium severity response
reached a probability of 0.35 at
cumulative SELs between 179 and 189
dB. These results again demonstrate that
the behavioral state and environment of
the animal mediates the likelihood of a
behavioral response, as do the
characteristics (e.g., frequency, energy
level) of the sound source itself.
The following subsections provide
examples of behavioral responses that
provide an idea of the variability in
behavioral responses that would be
expected given the differential
sensitivities of marine mammal species
to sound and the wide range of potential
acoustic sources to which a marine
mammal may be exposed. Behavioral
responses that could occur for a given
sound exposure should be determined
from the literature that is available for
each species, or extrapolated from
closely related species when no
information exists, along with
contextual factors.
Flight Response
A flight response is a dramatic change
in normal movement to a directed and
rapid movement away from the
perceived location of a sound source.
The flight response differs from other
avoidance responses in the intensity of
the response (e.g., directed movement,
rate of travel). Relatively little
information on flight responses of
marine mammals to anthropogenic
signals exist, although observations of
flight responses to the presence of
predators have occurred (Connor and
Heithaus, 1996). The result of a flight
response could range from brief,
temporary exertion and displacement
from the area where the signal provokes
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
flight to, in extreme cases, being a
component of marine mammal
strandings associated with sonar
activities (Evans and England, 2001). If
marine mammals respond to Navy
vessels that are transmitting active sonar
in the same way that they might
respond to a predator, their probability
of flight responses should increase
when they perceive that Navy vessels
are approaching them directly, because
a direct approach may convey detection
and intent to capture (Burger and
Gochfeld, 1981, 1990; Cooper, 1997,
1998). There are limited data on flight
response for marine mammals in water;
however, there are examples of this
response in species on land. For
instance, the probability of flight
responses in Dall’s sheep Ovis dalli dalli
(Frid, 2001), hauled-out ringed seals
Phoca hispida (Born et al., 1999),
Pacific brant (Branta bernicl nigricans),
and Canada geese (B. canadensis)
increased as a helicopter or fixed-wing
aircraft more directly approached
groups of these animals (Ward et al.,
1999). Bald eagles (Haliaeetus
leucocephalus) perched on trees
alongside a river were also more likely
to flee from a paddle raft when their
perches were closer to the river or were
closer to the ground (Steidl and
Anthony, 1996).
Response to Predator
As discussed earlier, evidence
suggests that at least some marine
mammals have the ability to
acoustically identify potential predators.
For example, harbor seals that reside in
the coastal waters off British Columbia
are frequently targeted by certain groups
of killer whales, but not others. The
seals discriminate between the calls of
threatening and non-threatening killer
whales (Deecke et al., 2002), a capability
that should increase survivorship while
reducing the energy required for
attending to and responding to all killer
whale calls. The occurrence of masking
or hearing impairment provides a means
by which marine mammals may be
prevented from responding to the
acoustic cues produced by their
predators. Whether or not this is a
possibility depends on the duration of
the masking/hearing impairment and
the likelihood of encountering a
predator during the time that predator
cues are impeded.
Alteration of Diving or Movement
Changes in dive behavior can vary
widely. They may consist of increased
or decreased dive times and surface
intervals as well as changes in the rates
of ascent and descent during a dive (e.g.,
Frankel and Clark, 2000; Ng and Leung,
PO 00000
Frm 00027
Fmt 4701
Sfmt 4702
49681
2003; Nowacek et al. 2004; Goldbogen et
al., 2013a, 2013b). Variations in dive
behavior may reflect interruptions in
biologically significant activities (e.g.,
foraging) or they may be of little
biological significance. Variations in
dive behavior may also expose an
animal to potentially harmful
conditions (e.g., increasing the chance
of ship-strike) or may serve as an
avoidance response that enhances
survivorship. The impact of a variation
in diving resulting from an acoustic
exposure depends on what the animal is
doing at the time of the exposure and
the type and magnitude of the response.
Nowacek et al. (2004) reported
disruptions of dive behaviors in foraging
North Atlantic right whales when
exposed to an alerting stimulus, an
action, they noted, that could lead to an
increased likelihood of ship strike.
However, the whales did not respond to
playbacks of either right whale social
sounds or vessel noise, highlighting the
importance of the sound characteristics
in producing a behavioral reaction.
Conversely, Indo-Pacific humpback
dolphins have been observed to dive for
longer periods of time in areas where
vessels were present and/or
approaching (Ng and Leung, 2003). In
both of these studies, the influence of
the sound exposure cannot be
decoupled from the physical presence of
a surface vessel, thus complicating
interpretations of the relative
contribution of each stimulus to the
response. Indeed, the presence of
surface vessels, their approach, and
speed of approach, seemed to be
significant factors in the response of the
Indo-Pacific humpback dolphins (Ng
and Leung, 2003). Arranz et al. (2021)
attempted to distinguish effects of vessel
noise from vessel presence by
conducting a noise exposure experiment
which compared behavioral reactions of
resting short-finned pilot whale mothercalf pairs during controlled approaches
by a tour boat with two electric (136–
140 dB) or petrol engines (139–150 dB).
Approach speed (<4 knots), distance of
passes (60 m), and vessel features other
than engine noise remained the same
between the two experimental
conditions. Behavioral data was
collected via unmanned aerial vehicle
and activity budgets were calculated
from continuous focal follows. Mother
pilot whales rested less and calves
nursed less in response to both types of
boat engines compared to control
conditions (vessel >300 m, stationary in
neutral). However, they found no
significant impact on whale behaviors
when the boat approached with the
quieter electric engine, while resting
E:\FR\FM\11AUP2.SGM
11AUP2
49682
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
behavior decreased 29 percent and
nursing decreased 81 percent when the
louder petrol engine was installed in the
same vessel. Low-frequency signals of
the Acoustic Thermometry of Ocean
Climate (ATOC) sound source were not
found to affect dive times of humpback
whales in Hawaiian waters (Frankel and
Clark, 2000) or to overtly affect elephant
seal dives (Costa et al., 2003). They did,
however, produce subtle effects that
varied in direction and degree among
the individual seals, illustrating the
equivocal nature of behavioral effects
and consequent difficulty in defining
and predicting them. Lastly, as noted
previously, DeRuiter et al. (2013) noted
that distance from a sound source may
moderate marine mammal reactions in
their study of Cuvier’s beaked whales,
which showed the whales swimming
rapidly and silently away when a sonar
signal was 3.4–9.5 km away while
showing no such reaction to the same
signal when the signal was 118 km away
even though the received levels were
similar.
Foraging
Disruption of feeding behavior can be
difficult to correlate with anthropogenic
sound exposure, so it is usually inferred
by observed displacement from known
foraging areas, the appearance of
secondary indicators (e.g., bubble nets
or sediment plumes), or changes in dive
behavior. As for other types of
behavioral response, the frequency,
duration, and temporal pattern of signal
presentation, as well as differences in
species sensitivity, are likely
contributing factors to differences in
response in any given circumstance
(e.g., Croll et al., 2001; Harris et al.,
2017; Madsen et al., 2006a; Nowacek et
al.; 2004; Yazvenko et al., 2007). A
determination of whether foraging
disruptions incur fitness consequences
would require information on or
estimates of the energetic requirements
of the affected individuals and the
relationship between prey availability,
foraging effort and success, and the life
history stage of the animal.
Southall et al. (2019a) found that prey
availability was higher in the western
area of the Southern California Offshore
Range where Cuvier’s beaked whales
preferentially occurred, while prey
resources were lower in the eastern area
and moderate in the area just north of
the Range. This high prey availability
may indicate that fewer foraging dives
are needed to meet metabolic energy
requirements than would be needed in
another area with fewer resources.
Benoit-Bird et al. (2020) demonstrated
that differences in squid distribution
could be a substantial factor for beaked
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
whales’ habitat preference. The
researchers suggest that this be
considered when comparing beaked
whale habitat use both on and off Navy
ranges.
Noise from seismic surveys was not
found to impact the feeding behavior in
western grey whales off the coast of
Russia (Yazvenko et al., 2007). Visual
tracking, passive acoustic monitoring,
and movement recording tags were used
to quantify sperm whale behavior prior
to, during, and following exposure to air
gun arrays at received levels in the
range of 140–160 dB at distances of 7–
13 km, following a phase-in of sound
intensity and full array exposures at 1–
13 km (Madsen et al., 2006a; Miller et
al., 2009). Sperm whales did not exhibit
horizontal avoidance behavior at the
surface. However, foraging behavior
may have been affected. The sperm
whales exhibited 19 percent less vocal
(buzz) rate during full exposure relative
to post exposure, and the whale that
was approached most closely had an
extended resting period and did not
resume foraging until the air guns had
ceased firing. The remaining whales
continued to execute foraging dives
throughout exposure; however,
swimming movements during foraging
dives were six percent lower during
exposure than control periods (Miller et
al., 2009). These data raise concerns that
air gun surveys may impact foraging
behavior in sperm whales, although
more data are required to understand
whether the differences were due to
exposure or natural variation in sperm
whale behavior (Miller et al., 2009).
Balaenopterid whales exposed to
moderate low-frequency signals similar
to the ATOC sound source
demonstrated no variation in foraging
activity (Croll et al., 2001), whereas five
out of six North Atlantic right whales
exposed to an acoustic alarm
interrupted their foraging dives
(Nowacek et al., 2004). Although the
received SPLs were similar in the latter
two studies, the frequency, duration,
and temporal pattern of signal
presentation were different. These
factors, as well as differences in species
sensitivity, are likely contributing
factors to the differential response. Blue
whales exposed to mid-frequency sonar
in the Southern California Bight were
less likely to produce low frequency
calls usually associated with feeding
behavior (Melco´n et al., 2012). However,
Melco´n et al. (2012) were unable to
determine if suppression of low
frequency calls reflected a change in
their feeding performance or
abandonment of foraging behavior and
indicated that implications of the
documented responses are unknown.
PO 00000
Frm 00028
Fmt 4701
Sfmt 4702
Further, it is not known whether the
lower rates of calling actually indicated
a reduction in feeding behavior or social
contact since the study used data from
remotely deployed, passive acoustic
monitoring buoys. In contrast, blue
whales increased their likelihood of
calling when ship noise was present,
and decreased their likelihood of calling
in the presence of explosive noise,
although this result was not statistically
significant (Melco´n et al., 2012).
Additionally, the likelihood of an
animal calling decreased with the
increased received level of midfrequency sonar, beginning at a SPL of
approximately 110–120 dB re: 1 mPa
(Melco´n et al., 2012). Results from
behavioral response studies in Southern
California waters indicated that, in some
cases and at low received levels, tagged
blue whales responded to midfrequency sonar but that those responses
were generally brief, of low to moderate
severity, and highly dependent on
exposure context (Southall et al., 2011;
Southall et al., 2012b; Southall et al.,
2019b). Information on or estimates of
the energetic requirements of the
individuals and the relationship
between prey availability, foraging effort
and success, and the life history stage of
the animal will help better inform a
determination of whether foraging
disruptions incur fitness consequences.
Surface feeding blue whales did not
show a change in behavior in response
to mid-frequency simulated and real
sonar sources with received levels
between 90 and 179 dB re: 1 mPa, but
deep feeding and non-feeding whales
showed temporary reactions including
cessation of feeding, reduced initiation
of deep foraging dives, generalized
avoidance responses, and changes to
dive behavior. The behavioral responses
the researchers observed were generally
brief, of low to moderate severity, and
highly dependent on exposure context
(behavioral state, source-to-whale
horizontal range, and prey availability)
(DeRuiter et al., 2017; Goldbogen et al.,
2013b; Sivle et al., 2015). Goldbogen et
al. (2013b) indicate that disruption of
feeding and displacement could impact
individual fitness and health. However,
for this to be true, we would have to
assume that an individual whale could
not compensate for this lost feeding
opportunity by either immediately
feeding at another location, by feeding
shortly after cessation of acoustic
exposure, or by feeding at a later time.
There is no indication this is the case,
particularly since unconsumed prey
would likely still be available in the
environment in most cases following the
cessation of acoustic exposure.
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
Similarly, while the rates of foraging
lunges decrease in humpback whales
due to sonar exposure, there was
variability in the response across
individuals, with one animal ceasing to
forage completely and another animal
starting to forage during the exposure
(Sivle et al., 2016). In addition, almost
half of the animals that exhibited
avoidance behavior were foraging before
the exposure but the others were not;
the animals that exhibited avoidance
behavior while not feeding responded at
a slightly lower received level and
greater distance than those that were
feeding (Wensveen et al., 2017). These
findings indicate that the behavioral
state of the animal plays a role in the
type and severity of a behavioral
response. In fact, when the prey field
was mapped and used as a covariate in
similar models looking for a response in
the same blue whales, the response in
deep-feeding behavior by blue whales
was even more apparent, reinforcing the
need for contextual variables to be
included when assessing behavioral
responses (Friedlaender et al., 2016).
Breathing
Respiration naturally varies with
different behaviors and variations in
respiration rate as a function of acoustic
exposure can be expected to co-occur
with other behavioral reactions, such as
a flight response or an alteration in
diving. However, respiration rates in
and of themselves may be representative
of annoyance or an acute stress
response. Mean exhalation rates of gray
whales at rest and while diving were
found to be unaffected by seismic
surveys conducted adjacent to the whale
feeding grounds (Gailey et al., 2007).
Studies with captive harbor porpoises
showed increased respiration rates upon
introduction of acoustic alarms
(Kastelein et al., 2001; Kastelein et al.,
2006a) and emissions for underwater
data transmission (Kastelein et al.,
2005). Harbor porpoises did not respond
to the low-duty cycle mid-frequency
tones at any received level, but one did
respond to the high-duty cycle signal
with more jumping and increased
respiration rates (Kastelein et al.,
2018b). Harbor porpoises responded to
seal scarers with broadband signals up
to 44 kHz with a slight respiration
response at 117 dB re 1 mPa and an
avoidance response at 139 dB re 1 mPa,
but another scarer with a fundamental
(strongest) frequency of 18 kHz did not
have an avoidance response until 151
dB re 1 mPa (Kastelein et al., 2015e).
However, exposure of the same acoustic
alarm to a striped dolphin under the
same conditions did not elicit a
response (Kastelein et al., 2006a), again
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
highlighting the importance in
understanding species differences in the
tolerance of underwater noise when
determining the potential for impacts
resulting from anthropogenic sound
exposure. Lastly, Kastelein et al. (2019a)
examined the potential masking effect of
high sea state ambient noise on captive
harbor porpoise perception of and
response to high duty cycle playbacks of
AN/SQS–53C sonar signals by observing
their respiration rates. Results indicated
that sonar signals were not masked by
the high sea state noise, and received
levels at which responses were observed
were similar to those observed in prior
studies of harbor porpoise behavior.
Pilot whales exhibited reduced
breathing rates relative to their diving
behavior when the low frequency active
sonar levels were high (reaching 180 dB
re 1 mPa), but only on the first sonar
exposure; on subsequent exposures their
breathing rates increased (Isojunno et
al., 2018), indicating a change in
response tactic with additional
exposures.
Social Relationships
Social interactions between mammals
can be affected by noise via the
disruption of communication signals or
by the displacement of individuals.
Disruption of social relationships
therefore depends on the disruption of
other behaviors (e.g., avoidance,
masking, etc.). Sperm whales responded
to military sonar, apparently from a
submarine, by dispersing from social
aggregations, moving away from the
sound source, remaining relatively
silent, and becoming difficult to
approach (Watkins et al., 1985). In
contrast, sperm whales in the
Mediterranean that were exposed to
submarine sonar continued calling (J.
Gordon pers. comm. cited in Richardson
et al., 1995). Long-finned pilot whales
exposed to three types of disturbance—
playbacks of killer whale sounds, naval
sonar exposure, and tagging—resulted
in increased group sizes (Visser et al.,
2016). In response to sonar, pilot whales
also spent more time at the surface with
other members of the group (Visser et
al., 2016). However, social disruptions
must be considered in context of the
relationships that are affected. While
some disruptions may not have
deleterious effects, others, such as longterm or repeated disruptions of mother/
calf pairs or interruption of mating
behaviors, have the potential to affect
the growth and survival or reproductive
effort/success of individuals.
PO 00000
Frm 00029
Fmt 4701
Sfmt 4702
49683
Vocalizations (Also see Auditory
Masking Section)
Vocal changes in response to
anthropogenic noise can occur across
the repertoire of sound production
modes used by marine mammals, such
as whistling, echolocation click
production, calling, and singing.
Changes in vocalization behavior that
may result in response to anthropogenic
noise can occur for any of these modes
and may result from a need to compete
with an increase in background noise or
may reflect an increased vigilance or a
startle response. For example, in the
presence of potentially masking signals
(low-frequency active sonar), humpback
whales have been observed to increase
the length of their songs (Miller et al.,
2000; Fristrup et al., 2003). A similar
compensatory effect for the presence of
low-frequency vessel noise has been
suggested for right whales; right whales
have been observed to shift the
frequency content of their calls upward
while reducing the rate of calling in
areas of increased anthropogenic noise
(Parks et al., 2007; Rolland et al., 2012).
Killer whales off the northwestern coast
of the United States have been observed
to increase the duration of primary calls
once a threshold in observing vessel
density (e.g., whale watching) was
reached, which has been suggested as a
response to increased masking noise
produced by the vessels (Foote et al.,
2004; NOAA, 2014). In contrast, both
sperm and pilot whales potentially
ceased sound production during the
Heard Island feasibility test (Bowles et
al., 1994), although it cannot be
absolutely determined whether the
inability to acoustically detect the
animals was due to the cessation of
sound production or the displacement
of animals from the area.
Cerchio et al. (2014) used passive
acoustic monitoring to document the
presence of singing humpback whales
off the coast of northern Angola and to
opportunistically test for the effect of
seismic survey activity on the number of
singing whales. Two recording units
were deployed between March and
December 2008 in the offshore
environment; numbers of singers were
counted every hour. Generalized
Additive Mixed Models were used to
assess the effect of survey day
(seasonality), hour (diel variation),
moon phase, and received levels of
noise (measured from a single pulse
during each ten-minute sampled period)
on singer number. The number of
singers significantly decreased with
increasing received level of noise,
suggesting that humpback whale
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49684
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
communication was disrupted to some
extent by the survey activity.
Castellote et al. (2012) reported
acoustic and behavioral changes by fin
whales in response to shipping and air
gun noise. Acoustic features of fin
whale song notes recorded in the
Mediterranean Sea and northeast
Atlantic Ocean were compared for areas
with different shipping noise levels and
traffic intensities and during an air gun
survey. During the first 72 hours of the
survey, a steady decrease in song
received levels and bearings to singers
indicated that whales moved away from
the acoustic source and out of a Navy
study area. This displacement persisted
for a time period well beyond the 10day duration of air gun activity,
providing evidence that fin whales may
avoid an area for an extended period in
the presence of increased noise. The
authors hypothesize that fin whale
acoustic communication is modified to
compensate for increased background
noise and that a sensitization process
may play a role in the observed
temporary displacement.
Seismic pulses at average received
levels of 131 dB re 1 mPa2-s caused blue
whales to increase call production (Di
Iorio and Clark, 2010). In contrast,
McDonald et al. (1995) tracked a blue
whale with seafloor seismometers and
reported that it stopped vocalizing and
changed its travel direction at a range of
10 km from the seismic vessel
(estimated received level 143 dB re: 1
mPa peak-to-peak). Blackwell et al.
(2013) found that bowhead whale call
rates dropped significantly at onset of
air gun use at sites with a median
distance of 41–45 km from the survey.
Blackwell et al. (2015) expanded this
analysis to show that whales actually
increased calling rates as soon as air gun
signals were detectable before
ultimately decreasing calling rates at
higher received levels (i.e., 10-minute
cumulative sound exposure level (cSEL)
of ∼127 dB). Overall, these results
suggest that bowhead whales may adjust
their vocal output in an effort to
compensate for noise before ceasing
vocalization effort and ultimately
deflecting from the acoustic source
(Blackwell et al., 2013, 2015). Captive
bottlenose dolphins sometimes
vocalized after an exposure to impulse
sound from a seismic water gun
(Finneran et al., 2010a). These studies
demonstrate that even low levels of
noise received far from the noise source
can induce changes in vocalization and/
or behavioral responses.
Avoidance
Avoidance is the displacement of an
individual from an area or migration
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
path as a result of the presence of a
sound or other stressors. Richardson et
al. (1995) noted that avoidance reactions
are the most obvious manifestations of
disturbance in marine mammals.
Avoidance is qualitatively different
from the flight response, but also differs
in the magnitude of the response (i.e.,
directed movement, rate of travel, etc.).
Oftentimes avoidance is temporary, and
animals return to the area once the noise
has ceased. Acute avoidance responses
have been observed in captive porpoises
and pinnipeds exposed to a number of
different sound sources (Kastelein et al.,
2001; Finneran et al., 2003; Kastelein et
al., 2006a; Kastelein et al., 2006b;
Kastelein et al., 2015d; Kastelein et al.,
2015e; Kastelein et al., 2018b). Shortterm avoidance of seismic surveys, low
frequency emissions, and acoustic
deterrents have also been noted in wild
populations of odontocetes (Bowles et
al., 1994; Goold, 1996; 1998; Stone et
al., 2000; Morton and Symonds, 2002;
Hiley et al., 2021) and to some extent in
mysticetes (Gailey et al., 2007). Longerterm displacement is possible, however,
which may lead to changes in
abundance or distribution patterns of
the affected species in the affected
region if habituation to the presence of
the sound does not occur (e.g.,
Blackwell et al., 2004; Bejder et al.,
2006; Teilmann et al., 2006). Longer
term or repetitive/chronic displacement
for some dolphin groups and for
manatees has been suggested to be due
to the presence of chronic vessel noise
(Haviland-Howell et al., 2007; MiksisOlds et al., 2007). Gray whales have
been reported deflecting from customary
migratory paths in order to avoid noise
from air gun surveys (Malme et al.,
1984). Humpback whales showed
avoidance behavior in the presence of
an active air gun array during
observational studies and controlled
exposure experiments in western
Australia (McCauley et al., 2000a).
As discussed earlier, Forney et al.
(2017) detailed the potential effects of
noise on marine mammal populations
with high site fidelity, including
displacement and auditory masking,
noting that a lack of observed response
does not imply absence of fitness costs
and that apparent tolerance of
disturbance may have population-level
impacts that are less obvious and
difficult to document. Avoidance of
overlap between disturbing noise and
areas and/or times of particular
importance for sensitive species may be
critical to avoiding population-level
impacts because (particularly for
animals with high site fidelity) there
may be a strong motivation to remain in
PO 00000
Frm 00030
Fmt 4701
Sfmt 4702
the area despite negative impacts.
Forney et al. (2017) stated that, for these
animals, remaining in a disturbed area
may reflect a lack of alternatives rather
than a lack of effects. The authors
discuss several case studies, including
western Pacific gray whales, which are
a small population of mysticetes
believed to be adversely affected by oil
and gas development off Sakhalin
Island, Russia (Weller et al., 2002;
Reeves et al., 2005). Western gray
whales display a high degree of
interannual site fidelity to the area for
foraging purposes, and observations in
the area during air gun surveys have
shown the potential for harm caused by
displacement from such an important
area (Weller et al., 2006; Johnson et al.,
2007). Forney et al. (2017) also discuss
beaked whales, noting that
anthropogenic effects in areas where
they are resident could cause severe
biological consequences, in part because
displacement may adversely affect
foraging rates, reproduction, or health,
while an overriding instinct to remain
could lead to more severe acute effects.
In 1998, the Navy conducted a Low
Frequency Sonar Scientific Research
Program (LFS SRP) specifically to study
behavioral responses of several species
of marine mammals to exposure to LF
sound, including one phase that focused
on the behavior of gray whales to low
frequency sound signals. The objective
of this phase of the LFS SRP was to
determine whether migrating gray
whales respond more strongly to
received levels, sound gradient, or
distance from the source, and to
compare whale avoidance responses to
a LF source in the center of the
migration corridor versus in the offshore
portion of the migration corridor. A
single source was used to broadcast
LFAS sounds at received levels of 170–
178 dB re: 1 mPa. The Navy reported that
the whales showed some avoidance
responses when the source was moored
one mile (1.8 km) offshore, and located
within the migration path, but the
whales returned to their migration path
when they were a few kilometers
beyond the source. When the source
was moored two miles (3.7 km) offshore,
responses were much less, even when
the source level was increased to
achieve the same received levels in the
middle of the migration corridor as
whales received when the source was
located within the migration corridor
(Clark et al., 1999). In addition, the
researchers noted that the offshore
whales did not seem to avoid the louder
offshore source.
Also during the LFS SRP, researchers
sighted numerous odontocete and
pinniped species in the vicinity of the
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
sound exposure tests with LFA sonar.
The MF and HF hearing specialists
present in California and Hawaii
showed no immediately obvious
responses or changes in sighting rates as
a function of source conditions.
Consequently, the researchers
concluded that none of these species
had any obvious behavioral reaction to
LFA sonar signals at received levels
similar to those that produced only
minor short-term behavioral responses
in the baleen whales (i.e., LF hearing
specialists). Thus, for odontocetes, the
chances of injury and/or significant
behavioral responses to LFA sonar
would be low given the MF/HF
specialists’ observed lack of response to
LFA sounds during the LFS SRP and
due to the MF/HF frequencies to which
these animals are adapted to hear (Clark
and Southall, 2009).
Maybaum (1993) conducted sound
playback experiments to assess the
effects of MFAS on humpback whales in
Hawaiian waters. Specifically, she
exposed focal pods to sounds of a 3.3kHz sonar pulse, a sonar frequency
sweep from 3.1 to 3.6 kHz, and a control
(blank) tape while monitoring behavior,
movement, and underwater
vocalizations. The two types of sonar
signals differed in their effects on the
humpback whales, but both resulted in
avoidance behavior. The whales
responded to the pulse by increasing
their distance from the sound source
and responded to the frequency sweep
by increasing their swimming speeds
and track linearity. In the Caribbean,
sperm whales avoided exposure to midfrequency submarine sonar pulses, in
the range of 1000 Hz to 10,000 Hz (IWC,
2005).
Kvadsheim et al. (2007) conducted a
controlled exposure experiment in
which killer whales fitted with D-tags
were exposed to mid-frequency active
sonar (Source A: a 1.0 second upsweep
209 dB at 1–2 kHz every 10 seconds for
10 minutes; Source B: with a 1.0 second
upsweep 197 dB at 6–7 kHz every 10
seconds for 10 minutes). When exposed
to Source A, a tagged whale and the
group it was traveling with did not
appear to avoid the source. When
exposed to Source B, the tagged whales
along with other whales that had been
carousel feeding, where killer whales
cooperatively herd fish schools into a
tight ball towards the surface and feed
on the fish which have been stunned by
tailslaps, and subsurface feeding
(Simila, 1997) ceased feeding during the
approach of the sonar and moved
rapidly away from the source. When
exposed to Source B, Kvadsheim et al.
(2007) reported that a tagged killer
whale seemed to try to avoid further
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
exposure to the sound field by the
following behaviors: immediately
swimming away (horizontally) from the
source of the sound; engaging in a series
of erratic and frequently deep dives that
seemed to take it below the sound field;
or swimming away while engaged in a
series of erratic and frequently deep
dives. Although the sample sizes in this
study are too small to support statistical
analysis, the behavioral responses of the
killer whales were consistent with the
results of other studies.
Southall et al. (2007) reviewed the
available literature on marine mammal
hearing and physiological and
behavioral responses to human-made
sound with the goal of proposing
exposure criteria for certain effects. This
peer-reviewed compilation of literature
is very valuable, though Southall et al.
(2007) note that not all data are equal
and some have poor statistical power,
insufficient controls, and/or limited
information on received levels,
background noise, and other potentially
important contextual variables. Such
data were reviewed and sometimes used
for qualitative illustration, but no
quantitative criteria were recommended
for behavioral responses. All of the
studies considered, however, contain an
estimate of the received sound level
when the animal exhibited the indicated
response.
In the Southall et al. (2007)
publication, for the purposes of
analyzing responses of marine mammals
to anthropogenic sound and developing
criteria, the authors differentiate
between single pulse sounds, multiple
pulse sounds, and non-pulse sounds.
MFAS/HFAS are considered non-pulse
sounds. Southall et al. (2007)
summarize the studies associated with
low-frequency, mid-frequency, and
high-frequency cetacean and pinniped
responses to non-pulse sounds, based
strictly on received level, in Appendix
C of their article (referenced and
summarized in the following
paragraphs).
The studies that address responses of
low-frequency cetaceans to non-pulse
sounds include data gathered in the
field and related to several types of
sound sources (of varying similarity to
active sonar) including: vessel noise,
drilling and machinery playback, lowfrequency M-sequences (sine wave with
multiple phase reversals) playback,
tactical low-frequency active sonar
playback, drill ships, ATOC source, and
non-pulse playbacks. These studies
generally indicate no (or very limited)
responses to received levels in the 90 to
120 dB re: 1 mPa range and an increasing
likelihood of avoidance and other
behavioral effects in the 120 to 160 dB
PO 00000
Frm 00031
Fmt 4701
Sfmt 4702
49685
re: 1 mPa range. As mentioned earlier,
though, contextual variables play a very
important role in the reported responses
and the severity of effects are not linear
when compared to received level. Also,
few of the laboratory or field datasets
had common conditions, behavioral
contexts, or sound sources, so it is not
surprising that responses differ.
The studies that address responses of
mid-frequency cetaceans to non-pulse
sounds include data gathered both in
the field and the laboratory and related
to several different sound sources (of
varying similarity to active sonar)
including: pingers, drilling playbacks,
ship and ice-breaking noise, vessel
noise, Acoustic Harassment Devices
(AHDs), Acoustic Deterrent Devices
(ADDs), MFAS, and non-pulse bands
and tones. Southall et al. (2007) were
unable to come to a clear conclusion
regarding the results of these studies. In
some cases, animals in the field showed
significant responses to received levels
between 90 and 120 dB re: 1 mPa, while
in other cases these responses were not
seen in the 120 to 150 dB re: 1 mPa
range. The disparity in results was
likely due to contextual variation and
the differences between the results in
the field and laboratory data (animals
typically responded at lower levels in
the field).
The studies that address responses of
high-frequency cetaceans to non-pulse
sounds include data gathered both in
the field and the laboratory and related
to several different sound sources (of
varying similarity to active sonar)
including: pingers, AHDs, and various
laboratory non-pulse sounds. All of
these data were collected from harbor
porpoises. Southall et al. (2007)
concluded that the existing data
indicate that harbor porpoises are likely
sensitive to a wide range of
anthropogenic sounds at low received
levels (∼90 to 120 dB re: 1 mPa), at least
for initial exposures. All recorded
exposures above 140 dB re: 1 mPa
induced profound and sustained
avoidance behavior in wild harbor
porpoises (Southall et al., 2007). Rapid
habituation was noted in some but not
all studies. There are no data to indicate
whether other high frequency cetaceans
are as sensitive to anthropogenic sound
as harbor porpoises.
The studies that address the responses
of pinnipeds in water to non-impulsive
sounds include data gathered both in
the field and the laboratory and related
to several different sound sources
including: AHDs, ATOC, various nonpulse sounds used in underwater data
communication, underwater drilling,
and construction noise. Few studies
existed with enough information to
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49686
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
include them in the analysis. The
limited data suggested that exposures to
non-pulse sounds between 90 and 140
dB re: 1 mPa generally do not result in
strong behavioral responses in
pinnipeds in water, but no data exist at
higher received levels.
In 2007, the first in a series of
behavioral response studies (BRS) on
deep diving odontocetes conducted by
NMFS, Navy, and other scientists
showed one Blainville’s beaked whale
responding to an MFAS playback. Tyack
et al. (2011) indicates that the playback
began when the tagged beaked whale
was vocalizing at depth (at the deepest
part of a typical feeding dive), following
a previous control with no sound
exposure. The whale appeared to stop
clicking significantly earlier than usual,
when exposed to MF signals in the 130–
140 dB (rms) received level range. After
a few more minutes of the playback,
when the received level reached a
maximum of 140–150 dB, the whale
ascended on the slow side of normal
ascent rates with a longer than normal
ascent, at which point the exposure was
terminated. The results are from a single
experiment and a greater sample size is
needed before robust and definitive
conclusions can be drawn. Tyack et al.
(2011) also indicates that Blainville’s
beaked whales appear to be sensitive to
noise at levels well below expected TTS
(∼160 dB re: 1m Pa). This sensitivity was
manifested by an adaptive movement
away from a sound source. This
response was observed irrespective of
whether the signal transmitted was
within the band width of MFAS, which
suggests that beaked whales may not
respond to the specific sound
signatures. Instead, they may be
sensitive to any pulsed sound from a
point source in this frequency range of
the MFAS transmission. The response to
such stimuli appears to involve the
beaked whale increasing the distance
between it and the sound source.
Overall the results from the 2007–2008
study showed a change in diving
behavior of the Blainville’s beaked
whale to playback of MFAS and
predator sounds (Boyd et al., 2008;
Southall et al., 2009; Tyack et al., 2011).
Stimpert et al. (2014) tagged a Baird’s
beaked whale, which was subsequently
exposed to simulated MFAS. Received
levels of sonar on the tag increased to
a maximum of 138 dB re: 1mPa, which
occurred during the first exposure dive.
Some sonar received levels could not be
measured due to flow noise and surface
noise on the tag.
Reaction to mid-frequency sounds
included premature cessation of
clicking and termination of a foraging
dive, and a slower ascent rate to the
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
surface. Results from a similar
behavioral response study in southern
California waters were presented for the
2010–2011 field season (Southall et al.,
2011; DeRuiter et al., 2013b). DeRuiter
et al. (2013b) presented results from two
Cuvier’s beaked whales that were tagged
and exposed to simulated MFAS during
the 2010 and 2011 field seasons of the
southern California behavioral response
study. The 2011 whale was also
incidentally exposed to MFAS from a
distant naval exercise. Received levels
from the MFAS signals from the
controlled and incidental exposures
were calculated as 84–144 and 78–106
dB re: 1 mPa rms, respectively. Both
whales showed responses to the
controlled exposures, ranging from
initial orientation changes to avoidance
responses characterized by energetic
fluking and swimming away from the
source. However, the authors did not
detect similar responses to incidental
exposure to distant naval sonar
exercises at comparable received levels,
indicating that context of the exposures
(e.g., source proximity, controlled
source ramp-up) may have been a
significant factor. Specifically, this
result suggests that caution is needed
when using marine mammal response
data collected from smaller, nearer
sound sources to predict at what
received levels animals may respond to
larger sound sources that are
significantly farther away—as the
distance of the source appears to be an
important contextual variable and
animals may be less responsive to
sources at notably greater distances.
Cuvier’s beaked whale responses
suggested particular sensitivity to sound
exposure as consistent with results for
Blainville’s beaked whale. Similarly,
beaked whales exposed to sonar during
British training exercises stopped
foraging (DSTL, 2007), and preliminary
results of controlled playback of sonar
may indicate feeding/foraging
disruption of killer whales and sperm
whales (Miller et al., 2011).
In the 2007–2008 Bahamas study,
playback sounds of a potential
predator—a killer whale—resulted in a
similar but more pronounced reaction,
which included longer inter-dive
intervals and a sustained straight-line
departure of more than 20 km from the
area (Boyd et al., 2008; Southall et al.,
2009; Tyack et al., 2011). The authors
noted, however, that the magnified
reaction to the predator sounds could
represent a cumulative effect of
exposure to the two sound types since
killer whale playback began
approximately 2 hours after MF source
playback. Pilot whales and killer whales
PO 00000
Frm 00032
Fmt 4701
Sfmt 4702
off Norway also exhibited horizontal
avoidance of a transducer with outputs
in the mid-frequency range (signals in
the 1–2 kHz and 6–7 kHz ranges) (Miller
et al., 2011). Additionally, separation of
a calf from its group during exposure to
MFAS playback was observed on one
occasion (Miller et al., 2011, 2012).
Miller et al. (2012) noted that this single
observed mother-calf separation was
unusual for several reasons, including
the fact that the experiment was
conducted in an unusually narrow fjord
roughly one km wide and that the sonar
exposure was started unusually close to
the pod including the calf. Both of these
factors could have contributed to calf
separation. In contrast, preliminary
analyses suggest that none of the pilot
whales or false killer whales in the
Bahamas showed an avoidance response
to controlled exposure playbacks
(Southall et al., 2009).
In the 2010 BRS study, researchers
again used controlled exposure
experiments to carefully measure
behavioral responses of individual
animals to sound exposures of MFAS
and pseudo-random noise. For each
sound type, some exposures were
conducted when animals were in a
surface feeding (approximately 164 ft
(50 m) or less) and/or socializing
behavioral state and others while
animals were in a deep feeding (greater
than 164 ft (50 m)) and/or traveling
mode. The researchers conducted the
largest number of controlled exposure
experiments on blue whales (n=19) and
of these, 11 controlled exposure
experiments involved exposure to the
MFAS sound type. For the majority of
controlled exposure experiment
transmissions of either sound type, they
noted few obvious behavioral responses
detected either by the visual observers
or on initial inspection of the tag data.
The researchers observed that
throughout the controlled exposure
experiment transmissions, up to the
highest received sound level (absolute
RMS value approximately 160 dB re: 1
mPa with signal-to-noise ratio values
over 60 dB), two blue whales continued
surface feeding behavior and remained
at a range of around 3,820 ft (1,000 m)
from the sound source (Southall et al.,
2011). In contrast, another blue whale
(later in the day and greater than 11.5
mi (18.5 km; 10 nmi) from the first
controlled exposure experiment
location) exposed to the same stimulus
(MFA) while engaged in a deep feeding/
travel state exhibited a different
response. In that case, the blue whale
responded almost immediately
following the start of sound
transmissions when received sounds
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
were just above ambient background
levels (Southall et al., 2011). The
authors note that this kind of temporary
avoidance behavior was not evident in
any of the nine controlled exposure
experiments involving blue whales
engaged in surface feeding or social
behaviors, but was observed in three of
the ten controlled exposure experiments
for blue whales in deep feeding/travel
behavioral modes (one involving MFA
sonar; two involving pseudo-random
noise) (Southall et al., 2011). The results
of this study, as well as the results of the
DeRuiter et al. (2013b) study of Cuvier’s
beaked whales discussed above, further
illustrate the importance of behavioral
context in understanding and predicting
behavioral responses.
Through analysis of the behavioral
response studies, a preliminary
overarching effect of greater sensitivity
to all anthropogenic exposures was seen
in beaked whales compared to the other
odontocetes studied (Southall et al.,
2009). Therefore, recent studies have
focused specifically on beaked whale
responses to active sonar transmissions
or controlled exposure playback of
simulated sonar on various military
ranges (Defence Science and
Technology Laboratory, 2007; Claridge
and Durban, 2009; Moretti et al., 2009;
McCarthy et al., 2011; Miller et al.,
2012; Southall et al., 2011, 2012a,
2012b, 2013, 2014; Tyack et al., 2011).
In the Bahamas, Blainville’s beaked
whales located on the instrumented
range will move off-range during sonar
use and return only after the sonar
transmissions have stopped, sometimes
taking several days to do so (Claridge
and Durban 2009; Moretti et al., 2009;
McCarthy et al., 2011; Tyack et al.,
2011). Moretti et al. (2014) used
recordings from seafloor-mounted
hydrophones at the Atlantic Undersea
Test and Evaluation Center (AUTEC) to
analyze the probability of Blainsville’s
beaked whale dives before, during, and
after Navy sonar exercises.
Southall et al. (2016) indicates that
results from Tyack et al. (2011), Miller
et al. (2015), Stimpert et al. (2014), and
DeRuiter et al. (2013b) beaked whale
studies demonstrate clear, strong, and
pronounced but varied behavioral
changes including avoidance with
associated energetic swimming and
cessation of individual foraging dives at
quite low received levels (∼100 to 135
dB re: 1 mPa) for exposures to simulated
or active MF military sonars (1–8 kHz)
with sound sources approximately 2–5
km away. Similar responses by beaked
whales to sonar have been documented
by Stimpert et al. (2014), Falcone et al.
(2017), DiMarzio et al. (2018), and Joyce
et al. (2019). Jones-Todd et al. (2021)
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
developed a discrete-space, continuoustime analysis to estimate animal
occurrence and unique movement
probability into and out of an area over
time, in response to sonar. They argue
that existing models in the field are
inappropriate for estimating a whale’s
exposure to sonar longitudinally and
across multiple exercises; most models
treat each day independently and don’t
consider repeated exposures over longer
periods. This model also allows for
individual variation in movement data.
Using seven tagged Blainville’s beaked
whales’ telemetry data, the model
showed transition rates across an area’s
borders changing in response to sonar
exposure, reflecting an avoidance
response that lasted approximately 3
days after the end of the exposure.
However, there are a number of
variables influencing response or nonresponse including source distance
(close vs. far), received sound levels,
and other contextual variables such as
other sound sources (e.g., vessels, etc.)
(Manzano-Roth et al., 2016; Falcone et
al., 2017; Harris et al., 2018). Wensveen
et al. (2019) found northern bottlenose
whales to avoid sonar out to distances
of 28 km, but these distances are well
in line with those observed on Navy
ranges (Manzano-Roth et al., 2016; Joyce
et al., 2019) where the animals return
once the sonar has ceased. When
exposed to especially long durations of
naval sonar (up to 13 consecutive hours,
repeatedly over 8 days), Cuvier’s beaked
whale detection rates remained low
even 7 days after the exercise. In
addition, a Mesoplodont beaked whale
species was entirely displaced from the
area during and at least 7 days after the
sonar activity (Stanistreet et al., 2022).
Furthermore, beaked whales have also
shown response to other non-sonar
anthropogenic sounds such as
commercial shipping and echosounders
(Soto et al., 2006; Pirotta et al., 2012;
Cholewiak et al., 2017). Pirotta et al.
(2012) documented broadband ship
noise causing a significant change in
beaked whale behavior up to at least 5.2
km away from the vessel. Even though
beaked whales appear to be sensitive to
anthropogenic sounds, the level of
response at the population level does
not appear to be significant based on
over a decade of research at two heavily
used Navy training areas in the Pacific
(Falcone et al., 2012; Schorr et al., 2014;
DiMarzio et al., 2018; Schorr et al.,
2019). With the exception of seasonal
patterns, DiMarzio et al. (2018) did not
detect any changes in annual Cuvier’s
beaked whale abundance estimates in
Southern California derived from
passive acoustic echolocation detections
PO 00000
Frm 00033
Fmt 4701
Sfmt 4702
49687
over 9 years (2010–2018). Similar
results for Blainville’s beaked whales
abundance estimates over several years
was documented in Hawaii (Henderson
et al., 2016; DiMarzio et al., 2018).
Visually, there have been documented
repeated sightings in southern
California of the same individual
Cuvier’s beaked whales over 10 years,
sightings of mother-calf pairs, and
sightings of the same mothers with their
second calf (Falcone et al., 2012; Schorr
et al., 2014; Schorr et al., 2019; Schorr,
unpublished data).
Baleen whales have shown a variety
of responses to impulse sound sources,
including avoidance, reduced surface
intervals, altered swimming behavior,
and changes in vocalization rates
(Richardson et al., 1995; Gordon et al.,
2003; Southall, 2007). While most
bowhead whales did not show active
avoidance until within 8 km of seismic
vessels (Richardson et al., 1995), some
whales avoided vessels by more than 20
km at received levels as low as 120 dB
re: 1 mPa rms. Additionally, Malme et al.
(1988) observed clear changes in diving
and respiration patterns in bowheads at
ranges up to 73 km from seismic vessels,
with received levels as low as 125 dB re:
1 mPa.
Gray whales migrating along the
United States West Coast showed
avoidance responses to seismic vessels
by 10 percent of animals at 164 dB re:
1 mPa, and by 90 percent of animals at
190 dB re: 1 mPa, with similar results for
whales in the Bering Sea (Malme, 1986;
1988). In contrast, noise from seismic
surveys was not found to impact feeding
behavior or exhalation rates while
resting or diving in western gray whales
off the coast of Russia (Yazvenko et al.,
2007; Gailey et al., 2007).
Humpback whales showed avoidance
behavior at ranges of 5–8 km from a
seismic array during observational
studies and controlled exposure
experiments in western Australia
(McCauley, 1998; Todd et al., 1996).
Todd et al. (1996) found no clear shortterm behavioral responses by foraging
humpbacks to explosions associated
with construction operations in
Newfoundland, but did see a trend of
increased rates of net entanglement and
a shift to a higher incidence of net
entanglement closer to the noise source.
The strongest baleen whale response
in any behavioral response study was
observed in a minke whale in the 3S2
study, which responded at 146 dB re: 1
mPa by strongly avoiding the sound
source (Kvadsheim et al., 2017; Sivle et
al., 2015). Although the minke whale
increased its swim speed, directional
movement, and respiration rate, none of
these were greater than rates observed in
E:\FR\FM\11AUP2.SGM
11AUP2
49688
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
baseline behavior, and its dive behavior
remained similar to baseline dives. A
minke whale tagged in the Southern
California behavioral response study
also responded by increasing its
directional movement, but maintained
its speed and dive patterns, and so did
not demonstrate as strong of a response
(Kvadsheim et al., 2017). In addition,
the 3S2 minke whale demonstrated
some of the same avoidance behavior
during the controlled ship approach
with no sonar, indicating at least some
of the response was to the vessel
(Kvadsheim et al., 2017). Martin et al.
(2015) found that the density of calling
minke whales was reduced during
periods of Navy training involving sonar
relative to the periods before training,
and increased again in the days after
training was completed. The responses
of individual whales could not be
assessed, so in this case it is unknown
whether the decrease in calling animals
indicated that the animals left the range,
or simply ceased calling. Similarly,
minke whale detections made using
Marine Acoustic Recording Instruments
off Jacksonville, FL, were reduced or
ceased altogether during periods of
sonar use (Simeone et al., 2015; U.S.
Department of the Navy, 2013b),
especially with an increased ping rate
(Charif et al., 2015). Harris et al. (2019b)
utilized acoustically generated minke
whale tracks at the U.S. Navy’s Pacific
Missile Range Facility to statistically
demonstrate changes in the spatial
distribution of minke whale acoustic
presence before, during, and after
surface ship mid-frequency active sonar
training. The spatial distribution of
probability of acoustic presence was
different in the ‘‘During’’ phase
compared to the ‘‘Before’’ phase, and
the probability of presence at the center
of ship activity for the ‘‘During’’ phase
was close to zero for both years. The
‘‘After’’ phases for both years retained
lower probabilities of presence,
suggesting the return to baseline
conditions may take more than 5 days.
While the results show a clear spatial
redistribution of calling minke whales
during surface ship mid-frequency
active sonar training, a limitation of
passive acoustic monitoring is that one
cannot conclude if the whales moved
away, went silent, or a combination of
the two.
Orientation
A shift in an animal’s resting state or
an attentional change via an orienting
response represent behaviors that would
be considered mild disruptions if
occurring alone. As previously
mentioned, the responses may co-occur
with other behaviors; for instance, an
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
animal may initially orient toward a
sound source, and then move away from
it. Thus, any orienting response should
be considered in context of other
reactions that may occur.
Continued Pre-Disturbance Behavior
and Habituation
Under some circumstances, some of
the individual marine mammals that are
exposed to active sonar transmissions
will continue their normal behavioral
activities. In other circumstances,
individual animals will respond to
sonar transmissions at lower received
levels and move to avoid additional
exposure or exposures at higher
received levels (Richardson et al., 1995).
It is difficult to distinguish between
animals that continue their predisturbance behavior without stress
responses, animals that continue their
behavior but experience stress responses
(that is, animals that cope with
disturbance), and animals that habituate
to disturbance (that is, they may have
experienced low-level stress responses
initially, but those responses abated
over time). Watkins (1986) reviewed
data on the behavioral reactions of fin,
humpback, right, and minke whales that
were exposed to continuous, broadband
low-frequency shipping and industrial
noise in Cape Cod Bay. He concluded
that underwater sound was the primary
cause of behavioral reactions in these
species of whales and that the whales
responded behaviorally to acoustic
stimuli within their respective hearing
ranges. Watkins also noted that whales
showed the strongest behavioral
reactions to sounds in the 15 Hz to 28
kHz range, although negative reactions
(avoidance, interruptions in
vocalizations, etc.) were generally
associated with sounds that were either
unexpected, too loud, suddenly louder
or different, or perceived as being
associated with a potential threat (such
as an approaching ship on a collision
course). In particular, whales seemed to
react negatively when they were within
100 m of the source or when received
levels increased suddenly in excess of
12 dB relative to ambient sounds. At
other times, the whales ignored the
source of the signal and all four species
habituated to these sounds.
Nevertheless, Watkins concluded that
whales ignored most sounds in the
background of ambient noise, including
sounds from distant human activities
even though these sounds may have had
considerable energies at frequencies
well within the whales’ range of
hearing. Further, he noted that of the
whales observed, fin whales were the
most sensitive of the four species,
followed by humpback whales; right
PO 00000
Frm 00034
Fmt 4701
Sfmt 4702
whales were the least likely to be
disturbed and generally did not react to
low-amplitude engine noise. By the end
of his period of study, Watkins (1986)
concluded that fin and humpback
whales had generally habituated to the
continuous and broad-band noise of
Cape Cod Bay while right whales did
not appear to change their response. As
mentioned above, animals that habituate
to a particular disturbance may have
experienced low-level stress responses
initially, but those responses abated
over time. In most cases, this likely
means a lessened immediate potential
effect from a disturbance. However,
there is cause for concern where the
habituation occurs in a potentially more
harmful situation. For example, animals
may become more vulnerable to vessel
strikes once they habituate to vessel
traffic (Swingle et al., 1993; Wiley et al.,
1995).
Aicken et al. (2005) monitored the
behavioral responses of marine
mammals to a new low-frequency active
sonar system used by the British Navy
(which would be considered midfrequency active sonar under this rule as
it operates at frequencies greater than
1,000 Hz). During those trials, fin
whales, sperm whales, Sowerby’s
beaked whales, long-finned pilot
whales, Atlantic white-sided dolphins,
and common bottlenose dolphins were
observed and their vocalizations were
recorded. These monitoring studies
detected no evidence of behavioral
responses that the investigators could
attribute to exposure to the lowfrequency active sonar during these
trials.
Explosive Sources
Underwater explosive detonations
send a shock wave and sound energy
through the water and can release
gaseous by-products, create an
oscillating bubble, or cause a plume of
water to shoot up from the water
surface. The shock wave and
accompanying noise are of most concern
to marine animals. Depending on the
intensity of the shock wave and size,
location, and depth of the animal, an
animal can be injured, killed, suffer
non-lethal physical effects, experience
hearing related effects with or without
behavioral responses, or exhibit
temporary behavioral responses or
tolerance from hearing the blast sound.
Generally, exposures to higher levels of
impulse and pressure levels would
result in greater impacts to an
individual animal.
Injuries resulting from a shock wave
take place at boundaries between tissues
of different densities. Different
velocities are imparted to tissues of
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
different densities, and this can lead to
their physical disruption. Blast effects
are greatest at the gas-liquid interface
(Landsberg, 2000). Gas-containing
organs, particularly the lungs and
gastrointestinal tract, are especially
susceptible (Goertner, 1982; Hill, 1978;
Yelverton et al., 1973). Intestinal walls
can bruise or rupture, with subsequent
hemorrhage and escape of gut contents
into the body cavity. Less severe
gastrointestinal tract injuries include
contusions, petechiae (small red or
purple spots caused by bleeding in the
skin), and slight hemorrhaging
(Yelverton et al., 1973).
Because the ears are the most
sensitive to pressure, they are the organs
most sensitive to injury (Ketten, 2000).
Sound-related damage associated with
sound energy from detonations can be
theoretically distinct from injury from
the shock wave, particularly farther
from the explosion. If a noise is audible
to an animal, it has the potential to
damage the animal’s hearing by causing
decreased sensitivity (Ketten, 1995).
Lethal impacts are those that result in
immediate death or serious debilitation
in or near an intense source and are not,
technically, pure acoustic trauma
(Ketten, 1995). Sublethal impacts
include hearing loss, which is caused by
exposures to perceptible sounds. Severe
damage (from the shock wave) to the
ears includes tympanic membrane
rupture, fracture of the ossicles, damage
to the cochlea, hemorrhage, and
cerebrospinal fluid leakage into the
middle ear. Moderate injury implies
partial hearing loss due to tympanic
membrane rupture and blood in the
middle ear. Permanent hearing loss also
can occur when the hair cells are
damaged by one very loud event, as well
as by prolonged exposure to a loud
noise or chronic exposure to noise (see
the Hearing Loss—Threshold Shift
section). The level of impact from blasts
depends on both an animal’s location
and, at outer zones, on its sensitivity to
the residual noise (Ketten, 1995).
Further Potential Effects of Behavioral
Disturbance on Marine Mammal Fitness
The different ways that marine
mammals respond to sound are
sometimes indicators of the ultimate
effect that exposure to a given stimulus
will have on the well-being (survival,
reproduction, etc.) of an animal. There
are few quantitative marine mammal
data relating the exposure of marine
mammals to sound to effects on
reproduction or survival, though data
exists for terrestrial species to which we
can draw comparisons for marine
mammals. Several authors have
reported that disturbance stimuli may
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
cause animals to abandon nesting and
foraging sites (Sutherland and
Crockford, 1993); may cause animals to
increase their activity levels and suffer
premature deaths or reduced
reproductive success when their energy
expenditures exceed their energy
budgets (Daan et al., 1996; Feare, 1976;
Mullner et al., 2004); or may cause
animals to experience higher predation
rates when they adopt risk-prone
foraging or migratory strategies (Frid
and Dill, 2002). Each of these studies
addressed the consequences of animals
shifting from one behavioral state (e.g.,
resting or foraging) to another
behavioral state (e.g., avoidance or
escape behavior) because of human
disturbance or disturbance stimuli.
One consequence of behavioral
avoidance results in the altered
energetic expenditure of marine
mammals because energy is required to
move and avoid surface vessels or the
sound field associated with active sonar
(Frid and Dill, 2002). Most animals can
avoid that energetic cost by swimming
away at slow speeds or speeds that
minimize the cost of transport (MiksisOlds, 2006), as has been demonstrated
in Florida manatees (Miksis-Olds, 2006).
Those energetic costs increase,
however, when animals shift from a
resting state, which is designed to
conserve an animal’s energy, to an
active state that consumes energy the
animal would have conserved had it not
been disturbed. Marine mammals that
have been disturbed by anthropogenic
noise and vessel approaches are
commonly reported to shift from resting
to active behavioral states, which would
imply that they incur an energy cost.
Morete et al. (2007) reported that
undisturbed humpback whale cows that
were accompanied by their calves were
frequently observed resting while their
calves circled them (milling). When
vessels approached, the amount of time
cows and calves spent resting and
milling, respectively, declined
significantly. These results are similar to
those reported by Scheidat et al. (2004)
for the humpback whales they observed
off the coast of Ecuador.
Constantine and Brunton (2001)
reported that bottlenose dolphins in the
Bay of Islands, New Zealand, engaged in
resting behavior just 5 percent of the
time when vessels were within 300 m,
compared with 83 percent of the time
when vessels were not present.
However, Heenehan et al. (2016) report
that results of a study of the response of
Hawaiian spinner dolphins to human
disturbance suggest that the key factor is
not the sheer presence or magnitude of
human activities, but rather the directed
interactions and dolphin-focused
PO 00000
Frm 00035
Fmt 4701
Sfmt 4702
49689
activities that elicit responses from
dolphins at rest. This information again
illustrates the importance of context in
regard to whether an animal will
respond to a stimulus. Miksis-Olds
(2006) and Miksis-Olds et al. (2005)
reported that Florida manatees in
Sarasota Bay, Florida, reduced the
amount of time they spent milling and
increased the amount of time they spent
feeding when background noise levels
increased. Although the acute costs of
these changes in behavior are not likely
to exceed an animal’s ability to
compensate, the chronic costs of these
behavioral shifts are uncertain.
Attention is the cognitive process of
selectively concentrating on one aspect
of an animal’s environment while
ignoring other things (Posner, 1994).
Because animals (including humans)
have limited cognitive resources, there
is a limit to how much sensory
information they can process at any
time. The phenomenon called
‘‘attentional capture’’ occurs when a
stimulus (usually a stimulus that an
animal is not concentrating on or
attending to) ‘‘captures’’ an animal’s
attention. This shift in attention can
occur consciously or subconsciously
(for example, when an animal hears
sounds that it associates with the
approach of a predator) and the shift in
attention can be sudden (Dukas, 2002;
van Rij, 2007). Once a stimulus has
captured an animal’s attention, the
animal can respond by ignoring the
stimulus, assuming a ‘‘watch and wait’’
posture, or treat the stimulus as a
disturbance and respond accordingly,
which includes scanning for the source
of the stimulus or ‘‘vigilance’’
(Cowlishaw et al., 2004).
Vigilance is normally an adaptive
behavior that helps animals determine
the presence or absence of predators,
assess their distance from conspecifics,
or to attend cues from prey (Bednekoff
and Lima, 1998; Treves, 2000). Despite
those benefits, however, vigilance has a
cost of time; when animals focus their
attention on specific environmental
cues, they are not attending to other
activities such as foraging or resting.
These effects have generally not been
demonstrated for marine mammals, but
studies involving fish and terrestrial
animals have shown that increased
vigilance may substantially reduce
feeding rates (Saino, 1994; Beauchamp
and Livoreil, 1997; Fritz et al., 2002;
Purser and Radford, 2011). Animals will
spend more time being vigilant (which
may translate to less time foraging or
resting) when disturbance stimuli
approach an animal more directly,
remain at closer distances, have a
greater group size (e.g., multiple surface
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49690
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
vessels), or co-occur with times that an
animal perceives increased risk (e.g.,
when they are giving birth or
accompanied by a calf). An example of
this concept with terrestrial species
involved bighorn sheep and Dall’s
sheep, which dedicated more time being
vigilant, and less time resting or
foraging, when aircraft made direct
approaches over them (Frid, 2001;
Stockwell et al., 1991). Vigilance has
also been documented in pinnipeds at
haul-out sites where resting may be
disturbed when seals become alerted
and/or flush into the water due to a
variety of disturbances, which may be
anthropogenic (noise and/or visual
stimuli) or due to other natural causes
such as other pinnipeds (Richardson et
al., 1995; Southall et al., 2007;
VanBlaricom, 2010; Lozano and Hente,
2014).
Chronic disturbance can cause
population declines through reduction
of fitness (e.g., decline in body
condition) and subsequent reduction in
reproductive success, survival, or both
(e.g., Harrington and Veitch, 1992; Daan
et al., 1996; Bradshaw et al., 1998). For
example, Madsen (1994) reported that
pink-footed geese (Anser
brachyrhynchus) in undisturbed habitat
gained body mass and had about a 46
percent reproductive success rate
compared with geese in disturbed
habitat (being consistently scared off the
fields on which they were foraging)
which did not gain mass and had a 17
percent reproductive success rate.
Similar reductions in reproductive
success have been reported for mule
deer (Odocoileus hemionus) disturbed
by all-terrain vehicles (Yarmoloy et al.,
1988), caribou (Rangifer tarandus
caribou) disturbed by seismic
exploration blasts (Bradshaw et al.,
1998), and caribou disturbed by lowelevation military jet fights (Luick et al.,
1996; Harrington and Veitch, 1992).
Similarly, a study of elk (Cervus
elaphus) that were disturbed
experimentally by pedestrians
concluded that the ratio of young to
mothers was inversely related to
disturbance rate (Phillips and
Alldredge, 2000). However, Ridgway et
al. (2006) reported that increased
vigilance in bottlenose dolphins
exposed to sound over a five-day period
in open-air, open-water enclosures in
San Diego Bay did not cause any sleep
deprivation or stress effects such as
changes in cortisol or epinephrine
levels.
The primary mechanism by which
increased vigilance and disturbance
appear to affect the fitness of individual
animals is by disrupting an animal’s
time budget and, as a result, reducing
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
the time they might spend foraging and
resting (which increases an animal’s
activity rate and energy demand while
decreasing their caloric intake/energy).
An example of this concept with
terrestrial species involved a study of
grizzly bears (Ursus horribilis) that
reported that bears disturbed by hikers
reduced their energy intake by an
average of 12 kilocalories/min (50.2 x
103 kiloJoules/min), and spent energy
fleeing or acting aggressively toward
hikers (White et al., 1999). In a separate
study, by integrating different sources of
data (e.g., controlled exposure data,
activity monitoring, telemetry tracking,
and prey sampling) into a theoretical
model to predict effects from sonar on
a blue whale’s daily energy intake,
Pirotta et al. (2021) found that tagged
blue whales’ activity budgets, lunging
rates, and ranging patterns caused
variability in their predicted cost of
disturbance.
Lusseau and Bejder (2007) present
data from three long-term studies
illustrating the connections between
disturbance from whale-watching boats
and population-level effects in
cetaceans. In Shark Bay, Australia, the
abundance of bottlenose dolphins was
compared within adjacent control and
tourism sites over three consecutive 4.5year periods of increasing tourism
levels. Between the second and third
time periods, in which tourism doubled,
dolphin abundance decreased by 15
percent in the tourism area and did not
change significantly in the control area.
In Fiordland, New Zealand, two
populations (Milford and Doubtful
Sounds) of bottlenose dolphins with
tourism levels that differed by a factor
of seven were observed and significant
increases in travelling time and
decreases in resting time were
documented for both. Consistent shortterm avoidance strategies were observed
in response to tour boats until a
threshold of disturbance was reached
(average 68 minutes between
interactions), after which the response
switched to a longer-term habitat
displacement strategy. For one
population, tourism only occurred in a
part of the home range. However,
tourism occurred throughout the home
range of the Doubtful Sound population
and once boat traffic increased beyond
the 68-minute threshold (resulting in
abandonment of their home range/
preferred habitat), reproductive success
drastically decreased (increased
stillbirths) and abundance decreased
significantly (from 67 to 56 individuals
in a short period). Last, in a study of
northern resident killer whales off
Vancouver Island, exposure to boat
PO 00000
Frm 00036
Fmt 4701
Sfmt 4702
traffic was shown to reduce foraging
opportunities and increase traveling
time. A simple bioenergetics model was
applied to show that the reduced
foraging opportunities equated to a
decreased energy intake of 18 percent,
while the increased traveling incurred
an increased energy output of 3–4
percent, which suggests that a
management action based on avoiding
interference with foraging might be
particularly effective.
On a related note, many animals
perform vital functions, such as feeding,
resting, traveling, and socializing, on a
diel cycle (24-hour cycle). Behavioral
reactions to noise exposure (such as
disruption of critical life functions,
displacement, or avoidance of important
habitat) are more likely to be significant
for fitness if they last more than one diel
cycle or recur on subsequent days
(Southall et al., 2007). Consequently, a
behavioral response lasting less than
one day and not recurring on
subsequent days is not considered
particularly severe unless it could
directly affect reproduction or survival
(Southall et al., 2007). It is important to
note the difference between behavioral
reactions lasting or recurring over
multiple days and anthropogenic
activities lasting or recurring over
multiple days. For example, just
because at-sea exercises last for multiple
days does not necessarily mean that
individual animals will be either
exposed to those activity-related
stressors (i.e., sonar) for multiple days or
further, exposed in a manner that would
result in sustained multi-day
substantive behavioral responses.
Stone (2015a) reported data from atsea observations during 1,196 airgun
surveys from 1994 to 2010. When large
arrays of airguns (considered in this
study to be 500 in3 or more) were firing,
lateral displacement, more localized
avoidance, or other changes in behavior
were evident for most odontocetes.
However, significant responses to large
arrays were found only for the minke
whale and fin whale. Behavioral
responses observed included changes in
swimming or surfacing behavior, with
indications that cetaceans remained
near the water surface at these times.
Cetaceans were recorded as feeding less
often when large arrays were active.
Monitoring of gray whales during an air
gun survey included recording whale
movements and respirations pre-,
during-, and post-seismic survey (Gailey
et al., 2016). Behavioral state and water
depth were the best ‘‘natural’’ predictors
of whale movements and respiration
and, after considering natural variation,
none of the response variables were
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
significantly associated with survey or
vessel sounds.
In order to understand how the effects
of activities may or may not impact
species and stocks of marine mammals,
it is necessary to understand not only
what the likely disturbances are going to
be, but how those disturbances may
affect the reproductive success and
survivorship of individuals, and then
how those impacts to individuals
translate to population-level effects.
Following on the earlier work of a
committee of the U.S. National Research
Council (NRC, 2005), New et al. (2014),
in an effort termed the Potential
Consequences of Disturbance (PCoD),
outline an updated conceptual model of
the relationships linking disturbance to
changes in behavior and physiology,
health, vital rates, and population
dynamics. In this framework, behavioral
and physiological changes can have
direct (acute) effects on vital rates, such
as when changes in habitat use or
increased stress levels raise the
probability of mother-calf separation or
predation; they can have indirect and
long-term (chronic) effects on vital rates,
such as when changes in time/energy
budgets or increased disease
susceptibility affect health, which then
affects vital rates; or they can have no
effect to vital rates (New et al., 2014). In
addition to outlining this general
framework and compiling the relevant
literature that supports it, the authors
chose four example species for which
extensive long-term monitoring data
exist (southern elephant seals, North
Atlantic right whales, Ziphidae beaked
whales, and bottlenose dolphins) and
developed state-space energetic models
that can be used to forecast longer-term,
population-level impacts from
behavioral changes. While these are
very specific models with very specific
data requirements that cannot yet be
applied broadly to project-specific risk
assessments for the majority of species,
as well as requiring significant resources
and time to conduct (more than is
typically available to support regulatory
compliance for one project), they are a
critical first step towards being able to
quantify the likelihood of a population
level effect.
Since New et al. (2014), several
publications have described models
developed to examine the long-term
effects of environmental or
anthropogenic disturbance of foraging
on various life stages of selected species
(sperm whale, Farmer et al. (2018);
California sea lion, McHuron et al.
(2018); blue whale, Pirotta et al. (2018a);
pilot whales, Hin et al. (2021); gray
whale, McHuron et al., 2021). These
models continue to add to refinement of
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
the approaches to the population
consequences of disturbance (PCOD)
framework. Such models also help
identify what data inputs require further
investigation. Pirotta et al. (2018b)
provides a review of the PCOD
framework with details on each step of
the process and approaches to applying
real data or simulations to achieve each
step.
New et al. (2020) found that closed
populations of dolphins could not
withstand a higher probability of
disturbance, compared to open
populations with no limitation on food.
Two bottlenose dolphin populations in
Australia were also modeled over 5
years against a number of disturbances
(Reed et al., 2020), and results indicated
that habitat/noise disturbance had little
overall impact on population
abundances in either location, even in
the most extreme impact scenarios
modeled. By integrating different
sources of data (e.g., controlled
exposure data, activity monitoring,
telemetry tracking, and prey sampling)
into a theoretical model to predict
effects from sonar on a blue whale’s
daily energy intake, Pirotta et al. (2021)
found that tagged blue whales’ activity
budgets, lunging rates, and ranging
patterns caused variability in their
predicted cost of disturbance. Dunlop et
al. (2021) modeled migrating humpback
whale mother-calf pairs in response to
seismic surveys using both a forwards
and backwards approach. While a
typical forwards approach can
determine if a stressor would have
population-level consequences, authors
demonstrated that working backwards
through a PCoD model can be used to
assess the ‘‘worst case’’ scenario for an
interaction of a target species and
stressor. This method may be useful for
future management goals when
appropriate data becomes available to
fully support the model. Harbor
porpoise movement and foraging were
modeled for baseline periods and then
for periods with seismic surveys as well;
the models demonstrated that the
seasonality of the seismic activity was
an important predictor of impact
(Gallagher et al., 2021). Murray et al.
(2021) conducted a cumulative effects
assessment on Northern and Southern
resident killer whales, which involved
both a Pathways of Effects conceptual
model and a Population Viability
Analysis quantitative simulation model.
Authors found that both populations
were highly sensitive to prey
abundance, and were also impacted by
the interaction of low prey abundance
with vessel strike, vessel noise, and
polychlorinated biphenyls
PO 00000
Frm 00037
Fmt 4701
Sfmt 4702
49691
contaminants. However, more research
is needed to validate the mechanisms of
vessel disturbance and environmental
containments. Czapanskiy et al. (2021)
modeled energetic costs associated with
behavioral response to mid-frequency
active sonar using datasets from eleven
cetaceans’ feeding rates, prey
characteristics, avoidance behavior, and
metabolic rates. Authors found that the
short-term energetic cost was influenced
more by lost foraging opportunities than
increased locomotor effort during
avoidance. Additionally, the model
found that mysticetes incurred more
energetic cost that odontocetes, even
during mild behavioral responses to
sonar.
Stranding and Mortality
The definition for a stranding under
title IV of the MMPA is that (A) a marine
mammal is dead and is (i) on a beach
or shore of the United States; or (ii) in
waters under the jurisdiction of the
United States (including any navigable
waters); or (B) a marine mammal is alive
and is (i) on a beach or shore of the
United States and is unable to return to
the water; (ii) on a beach or shore of the
United States and, although able to
return to the water, is in need of
apparent medical attention; or (iii) in
the waters under the jurisdiction of the
United States (including any navigable
waters), but is unable to return to its
natural habitat under its own power or
without assistance (see MMPA section
410(3)). This definition is useful for
considering stranding events even when
they occur beyond lands and waters
under the jurisdiction of the United
States.
Marine mammal strandings have been
linked to a variety of causes, such as
illness from exposure to infectious
agents, biotoxins, or parasites;
starvation; unusual oceanographic or
weather events; or anthropogenic causes
including fishery interaction, ship
strike, entrainment, entrapment, sound
exposure, or combinations of these
stressors sustained concurrently or in
series. Historically, the cause or causes
of most strandings have remained
unknown (Geraci et al., 1976; Eaton,
1979; Odell et al., 1980; Best, 1982), but
the development of trained, professional
stranding response networks and
improved analyses have led to a greater
understanding of marine mammal
stranding causes (Simeone and Moore
2017).
Numerous studies suggest that the
physiology, behavior, habitat, social
relationships, age, or condition of
cetaceans may cause them to strand or
might predispose them to strand when
exposed to another phenomenon. These
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49692
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
suggestions are consistent with the
conclusions of numerous other studies
that have demonstrated that
combinations of dissimilar stressors
commonly combine to kill an animal or
dramatically reduce its fitness, even
though one exposure without the other
does not produce the same result
(Bernaldo de Quiros et al., 2019;
Chroussos, 2000; Creel, 2005; DeVries et
al., 2003; Fair and Becker, 2000; Foley
et al., 2001; Moberg, 2000; Relyea,
2005a, 2005b; Romero, 2004; Sih et al.,
2004).
Historically, stranding reporting and
response efforts have been inconsistent,
although significant improvements have
occurred over the last 25 years.
Reporting forms for basic (‘‘Level A’’)
information, rehabilitation disposition,
and human interaction have been
standardized nationally (available at
https://www.fisheries.noaa.gov/
national/marine-mammal-protection/
level-data-collection-marine-mammalstranding-events). However, data
collected beyond basic information
varies by region (and may vary from
case to case), and are not standardized
across the United States. Logistical
conditions such as weather, time,
location, and decomposition state may
also affect the ability of the stranding
network to thoroughly examine a
specimen (Carretta et al., 2016b; Moore
et al., 2013). While the investigation of
stranded animals provides insight into
the types of threats marine mammal
populations face, full investigations are
only possible and conducted on a small
fraction of the total number of
strandings that occur, limiting our
understanding of the causes of
strandings (Carretta et al., 2016a).
Additionally, and due to the variability
in effort and data collected, the ability
to interpret long-term trends in stranded
marine mammals is complicated.
Several mass strandings (strandings
that involve two or more individuals of
the same species, excluding a single
mother-calf pair) that have occurred
over the past two decades have been
associated with anthropogenic activities
that introduced sound into the marine
environment such as naval operations
and seismic surveys. An in-depth
discussion of strandings is in the Navy’s
Technical Report on Marine Mammal
Strandings Associated with U.S. Navy
Sonar Activities (U.S. Navy Marine
Mammal Program & Space and Naval
Warfare Systems Command Center
Pacific, 2017).
Worldwide, there have been several
efforts to identify relationships between
cetacean mass stranding events and
military active sonar (Cox et al., 2006;
Hildebrand, 2004; IWC, 2005; Taylor et
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
al., 2004). For example, based on a
review of mass stranding events around
the world consisting of two or more
individuals of Cuvier’s beaked whales,
records from the International Whaling
Commission (IWC) (2005) show that a
quarter (9 of 41) were associated with
concurrent naval patrol, explosion,
maneuvers, or MFAS. D’Amico et al.
(2009) reviewed beaked whale stranding
data compiled primarily from the
published literature (which provides an
incomplete record of stranding events,
as many are not written up for
publication), along with unpublished
information from some regions of the
world.
Most of the stranding events reviewed
by the IWC involved beaked whales. A
mass stranding of Cuvier’s beaked
whales in the eastern Mediterranean Sea
occurred in 1996 (Frantzis, 1998), and
mass stranding events involving
Gervais’ beaked whales, Blainville’s
beaked whales, and Cuvier’s beaked
whales occurred off the coast of the
Canary Islands in the late 1980s
(Simmonds and Lopez-Jurado, 1991).
The stranding events that occurred in
the Canary Islands and Kyparissiakos
Gulf in the late 1990s and the Bahamas
in 2000 have been the most intensively
studied mass stranding events and have
been associated with naval maneuvers
involving the use of tactical sonar. Other
cetacean species with naval sonar
implicated in stranding events include
harbor porpoise (Phocoena phocoena)
(Norman et al., 2004; Wright et al.,
2013) and common dolphin (Delphinus
delphis) (Jepson and Deaville 2009).
Strandings Associated with Impulsive
Sound
Silver Strand
During a Navy training event on
March 4, 2011 at the Silver Strand
Training Complex in San Diego,
California, three or possibly four
dolphins were killed in an explosion.
During an underwater detonation
training event, a pod of 100 to 150 longbeaked common dolphins were
observed moving towards the 700-yd
(640.1 m) exclusion zone around the
explosive charge, monitored by
personnel in a safety boat and
participants in a dive boat.
Approximately 5 minutes remained on
a time-delay fuse connected to a single
8.76 lbs (3.97 kg) explosive charge (C–
4 and detonation cord). Although the
dive boat was placed between the pod
and the explosive in an effort to guide
the dolphins away from the area, that
effort was unsuccessful and three longbeaked common dolphins near the
explosion died. In addition to the three
dolphins found dead on March 4, the
PO 00000
Frm 00038
Fmt 4701
Sfmt 4702
remains of a fourth dolphin were
discovered on March 7, 2011 near
Oceanside, California (3 days later and
approximately 68 km north of the
detonation), which might also have been
related to this event. Association of the
fourth stranding with the training event
is uncertain because dolphins strand on
a regular basis in the San Diego area.
Details such as the dolphins’ depth and
distance from the explosive at the time
of the detonation could not be estimated
from the 250 yd (228.6 m) standoff point
of the observers in the dive boat or the
safety boat.
These dolphin mortalities are the only
known occurrence of a U.S. Navy
training or testing event involving
impulsive energy (underwater
detonation) that caused mortality or
injury to a marine mammal. Despite this
being a rare occurrence, NMFS and the
Navy reviewed training requirements,
safety procedures, and possible
mitigation measures and implemented
changes to reduce the potential for this
to occur in the future—specifically
increasing the size of the exclusion zone
to better account for the time-delay fuse
and the distance that marine mammals
might travel during the time delay.
Discussions of procedures associated
with in-air explosives at or above the
water surface during training are
presented in the Proposed Mitigation
Measures section.
Kyle of Durness, Scotland
On July 22, 2011 a mass stranding
event involving long-finned pilot
whales occurred at Kyle of Durness,
Scotland. An investigation by Brownlow
et al. (2015) considered unexploded
ordnance detonation activities at a
Ministry of Defense bombing range,
conducted by the Royal Navy prior to
and during the strandings, as a plausible
contributing factor in the mass stranding
event. While Brownlow et al. (2015)
concluded that the serial detonations of
underwater ordnance were an
influential factor in the mass stranding
event (along with the presence of a
potentially compromised animal and
navigational error in a topographically
complex region), they also suggest that
mitigation measures—which included
observations from a zodiac only and by
personnel not experienced in marine
mammal observation, among other
deficiencies—were likely insufficient to
assess if cetaceans were in the vicinity
of the detonations. The authors also cite
information from the Ministry of
Defense indicating ‘‘an extraordinarily
high level of activity’’ (i.e., frequency
and intensity of underwater explosions)
on the range in the days leading up to
the stranding.
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
Strandings Associated With Active
Sonar
Over the past 21 years, there have
been five stranding events coincident
with naval MF active sonar use in
which exposure to sonar is believed to
have been a contributing factor: Greece
(1996); the Bahamas (2000); Madeira
(2000); Canary Islands (2002); and Spain
(2006) (Cox et al., 2006; Fernandez,
2006; U.S. Navy Marine Mammal
Program & Space and Naval Warfare
Systems Command Center Pacific,
2017). These five mass strandings have
resulted in about 40 known cetacean
deaths consisting mostly of beaked
whales and with close linkages to midfrequency active sonar activity. In these
circumstances, exposure to nonimpulsive acoustic energy was
considered a potential indirect cause of
death of the marine mammals (Cox et
al., 2006). Only one of these stranding
events, the Bahamas (2000), was
associated with exercises conducted by
the U.S. Navy. Additionally, in 2004,
during the Rim of the Pacific (RIMPAC)
exercises, between 150 and 200 usually
pelagic melon-headed whales occupied
the shallow waters of Hanalei Bay,
Kauai, Hawaii for over 28 hours. NMFS
determined that MFAS was a plausible,
if not likely, contributing factor in what
may have been a confluence of events
that led to the Hanalei Bay stranding. A
number of other stranding events
coincident with the operation of MFAS,
including the death of beaked whales or
other species (minke whales, dwarf
sperm whales, pilot whales), have been
reported; however, the majority have
not been investigated to the degree
necessary to determine the cause of the
stranding. Most recently, the
Independent Scientific Review Panel
investigating potential contributing
factors to a 2008 mass stranding of
melon-headed whales in Antsohihy,
Madagascar released its final report
suggesting that the stranding was likely
initially triggered by an industry seismic
survey (Southall et al., 2013). This
report suggests that the operation of a
commercial high-powered 12 kHz multibeam echosounder during an industry
seismic survey was a plausible and
likely initial trigger that caused a large
group of melon-headed whales to leave
their typical habitat and then ultimately
strand as a result of secondary factors
such as malnourishment and
dehydration. The report indicates that
the risk of this particular convergence of
factors and ultimate outcome is likely
very low, but recommends that the
potential be considered in
environmental planning. Because of the
association between tactical mid-
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
frequency active sonar use and a small
number of marine mammal strandings,
the Navy and NMFS have been
considering and addressing the
potential for strandings in association
with Navy activities for years. In
addition to the proposed mitigation
measures intended to more broadly
minimize impacts to marine mammals,
the Navy would abide by the
Notification and Reporting Plan, which
sets out notification, reporting, and
other requirements when dead, injured,
or stranded marine mammals are
detected in certain circumstances.
Greece (1996)
Twelve Cuvier’s beaked whales
stranded atypically (in both time and
space) along a 38.2-km strand of the
Kyparissiakos Gulf coast on May 12 and
13, 1996 (Frantzis, 1998). From May 11
through May 15, the North Atlantic
Treaty Organization (NATO) research
vessel Alliance was conducting sonar
tests with signals of 600 Hz and 3 kHz
and source levels of 228 and 226 dB re:
1mPa, respectively (D’Amico and
Verboom, 1998; D’Spain et al., 2006).
The timing and location of the testing
encompassed the time and location of
the strandings (Frantzis, 1998).
Necropsies of eight of the animals
were performed but were limited to
basic external examination and
sampling of stomach contents, blood,
and skin. No ears or organs were
collected, and no histological samples
were preserved. No significant apparent
abnormalities or wounds were found,
however examination of photos of the
animals, taken soon after their death,
revealed that the eyes of at least four of
the individuals were bleeding (Frantzis,
2004). Stomach contents contained the
flesh of cephalopods, indicating that
feeding had recently taken place
(Frantzis, 1998).
All available information regarding
the conditions associated with this
stranding event was compiled, and
many potential causes were examined
including major pollution events,
prominent tectonic activity, unusual
physical or meteorological events,
magnetic anomalies, epizootics, and
conventional military activities
(International Council for the
Exploration of the Sea, 2005a).
However, none of these potential causes
coincided in time or space with the
mass stranding, or could explain its
characteristics (International Council for
the Exploration of the Sea, 2005a). The
robust condition of the animals, plus the
recent stomach contents, is inconsistent
with pathogenic causes. In addition,
environmental causes can be ruled out
as there were no unusual environmental
PO 00000
Frm 00039
Fmt 4701
Sfmt 4702
49693
circumstances or events before or during
this time period and within the general
proximity (Frantzis, 2004).
Because of the rarity of this mass
stranding of Cuvier’s beaked whales in
the Kyparissiakos Gulf (first one in
historical records), the probability for
the two events (the military exercises
and the strandings) to coincide in time
and location, while being independent
of each other, was thought to be
extremely low (Frantzis, 1998).
However, because full necropsies had
not been conducted, and no
abnormalities were noted, the cause of
the strandings could not be precisely
determined (Cox et al., 2006). A
Bioacoustics Panel convened by NATO
concluded that the evidence available
did not allow them to accept or reject
sonar exposures as a causal agent in
these stranding events. The analysis of
this stranding event provided support
for, but no clear evidence for, the causeand-effect relationship of tactical sonar
training activities and beaked whale
strandings (Cox et al., 2006).
Bahamas (2000)
NMFS and the Navy prepared a joint
report addressing the multi-species
stranding in the Bahamas in 2000,
which took place within 24 hours of
U.S. Navy ships using MFAS as they
passed through the Northeast and
Northwest Providence Channels on
March 15–16, 2000. The ships, which
operated both AN/SQS–53C and AN/
SQS–56, moved through the channel
while emitting sonar pings
approximately every 24 seconds. Of the
17 cetaceans that stranded over a 36hour period (Cuvier’s beaked whales,
Blainville’s beaked whales, minke
whales, and a spotted dolphin), seven
animals died on the beach (five Cuvier’s
beaked whales, one Blainville’s beaked
whale, and the spotted dolphin), while
the other 10 were returned to the water
alive (though their ultimate fate is
unknown). As discussed in the Bahamas
report (DOC/DON, 2001), there is no
likely association between the minke
whale and spotted dolphin strandings
and the operation of MFAS.
Necropsies were performed on five of
the stranded beaked whales. All five
necropsied beaked whales were in good
body condition, showing no signs of
infection, disease, ship strike, blunt
trauma, or fishery related injuries, and
three still had food remains in their
stomachs. Auditory structural damage
was discovered in four of the whales,
specifically bloody effusions or
hemorrhaging around the ears. Bilateral
intracochlear and unilateral temporal
region subarachnoid hemorrhage, with
blood clots in the lateral ventricles,
E:\FR\FM\11AUP2.SGM
11AUP2
49694
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
were found in two of the whales. Three
of the whales had small hemorrhages in
their acoustic fats (located along the jaw
and in the melon).
A comprehensive investigation was
conducted and all possible causes of the
stranding event were considered,
whether they seemed likely at the outset
or not. Based on the way in which the
strandings coincided with ongoing
naval activity involving tactical MFAS
use, in terms of both time and
geography, the nature of the
physiological effects experienced by the
dead animals, and the absence of any
other acoustic sources, the investigation
team concluded that MFAS aboard U.S.
Navy ships that were in use during the
active sonar exercise in question were
the most plausible source of this
acoustic or impulse trauma to beaked
whales. This sound source was active in
a complex environment that included
the presence of a surface duct, unusual
and steep bathymetry, a constricted
channel with limited egress, intensive
use of multiple, active sonar units over
an extended period of time, and the
presence of beaked whales that appear
to be sensitive to the frequencies
produced by these active sonars. The
investigation team concluded that the
cause of this stranding event was the
confluence of the Navy MFAS and these
contributory factors working together,
and further recommended that the Navy
avoid operating MFAS in situations
where these five factors would be likely
to occur. This report does not conclude
that all five of these factors must be
present for a stranding to occur, nor that
beaked whales are the only species that
could potentially be affected by the
confluence of the other factors. Based on
this, NMFS believes that the operation
of MFAS in situations where surface
ducts exist, or in marine environments
defined by steep bathymetry and/or
constricted channels may increase the
likelihood of producing a sound field
with the potential to cause cetaceans
(especially beaked whales) to strand,
and therefore, suggests the need for
increased vigilance while operating
MFAS in these areas, especially when
beaked whales (or potentially other
deep divers) are likely present.
Madeira, Portugal (2000)
From May 10–14, 2000, three Cuvier’s
beaked whales were found atypically
stranded on two islands in the Madeira
archipelago, Portugal (Cox et al., 2006).
A fourth animal was reported floating in
the Madeiran waters by a fisherman but
did not come ashore (Woods Hole
Oceanographic Institution, 2005). Joint
NATO amphibious training
peacekeeping exercises involving
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
participants from 17 countries and 80
warships, took place in Portugal during
May 2–15, 2000.
The bodies of the three stranded
whales were examined post mortem
(Woods Hole Oceanographic Institution,
2005), though only one of the stranded
whales was fresh enough (24 hours after
stranding) to be necropsied (Cox et al.,
2006). Results from the necropsy
revealed evidence of hemorrhage and
congestion in the right lung and both
kidneys (Cox et al., 2006). There was
also evidence of intercochlear and
intracranial hemorrhage similar to that
which was observed in the whales that
stranded in the Bahamas event (Cox et
al., 2006). There were no signs of blunt
trauma, and no major fractures (Woods
Hole Oceanographic Institution, 2005).
The cranial sinuses and airways were
found to be clear with little or no fluid
deposition, which may indicate good
preservation of tissues (Woods Hole
Oceanographic Institution, 2005).
Several observations on the Madeira
stranded beaked whales, such as the
pattern of injury to the auditory system,
are the same as those observed in the
Bahamas strandings. Blood in and
around the eyes, kidney lesions, pleural
hemorrhages, and congestion in the
lungs are particularly consistent with
the pathologies from the whales
stranded in the Bahamas, and are
consistent with stress and pressure
related trauma. The similarities in
pathology and stranding patterns
between these two events suggest that a
similar pressure event may have
precipitated or contributed to the
strandings at both sites (Woods Hole
Oceanographic Institution, 2005).
Even though no definitive causal link
can be made between the stranding
event and naval exercises, certain
conditions may have existed in the
exercise area that, in their aggregate,
may have contributed to the marine
mammal strandings (Freitas, 2004):
exercises were conducted in areas of at
least 547 fathoms (1,000 m) depth near
a shoreline where there is a rapid
change in bathymetry on the order of
547 to 3,281 fathoms (1,000 to 6,000 m)
occurring across a relatively short
horizontal distance (Freitas, 2004);
multiple ships were operating around
Madeira, though it is not known if
MFAS was used, and the specifics of the
sound sources used are unknown (Cox
et al., 2006, Freitas, 2004); and exercises
took place in an area surrounded by
landmasses separated by less than 35
nmi (65 km) and at least 10 nmi (19 km)
in length, or in an embayment. Exercises
involving multiple ships employing
MFAS near land may produce sound
directed towards a channel or
PO 00000
Frm 00040
Fmt 4701
Sfmt 4702
embayment that may cut off the lines of
egress for marine mammals (Freitas,
2004).
Canary Islands, Spain (2002)
The southeastern area within the
Canary Islands is well known for
aggregations of beaked whales due to its
ocean depths of greater than 547
fathoms (1,000 m) within a few hundred
meters of the coastline (Fernandez et al.,
2005). On September 24, 2002, 14
beaked whales were found stranded on
Fuerteventura and Lanzarote Islands in
the Canary Islands (International
Council for Exploration of the Sea,
2005a). Seven whales died, while the
remaining seven live whales were
returned to deeper waters (Fernandez et
al., 2005). Four beaked whales were
found stranded dead over the next 3
days either on the coast or floating
offshore. These strandings occurred
within close proximity of an
international naval exercise that utilized
MFAS and involved numerous surface
warships and several submarines.
Strandings began about 4 hours after the
onset of MFAS activity (International
Council for Exploration of the Sea,
2005a; Fernandez et al., 2005).
Eight Cuvier’s beaked whales, one
Blainville’s beaked whale, and one
Gervais’ beaked whale were necropsied,
6 of them within 12 hours of stranding
(Fernandez et al., 2005). No pathogenic
bacteria were isolated from the carcasses
(Jepson et al., 2003). The animals
displayed severe vascular congestion
and hemorrhage especially around the
tissues in the jaw, ears, brain, and
kidneys, displaying marked
disseminated microvascular
hemorrhages associated with
widespread fat emboli (Jepson et al.,
2003; International Council for
Exploration of the Sea, 2005a). Several
organs contained intravascular bubbles,
although definitive evidence of gas
embolism in vivo is difficult to
determine after death (Jepson et al.,
2003). The livers of the necropsied
animals were the most consistently
affected organ, which contained
macroscopic gas-filled cavities and had
variable degrees of fibrotic
encapsulation. In some animals,
cavitary lesions had extensively
replaced the normal tissue (Jepson et al.,
2003). Stomachs contained a large
amount of fresh and undigested
contents, suggesting a rapid onset of
disease and death (Fernandez et al.,
2005). Head and neck lymph nodes
were enlarged and congested, and
parasites were found in the kidneys of
all animals (Fernandez et al., 2005).
The association of NATO MFAS use
close in space and time to the beaked
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
whale strandings, and the similarity
between this stranding event and
previous beaked whale mass strandings
coincident with sonar use, suggests that
a similar scenario and causative
mechanism of stranding may be shared
between the events. Beaked whales
stranded in this event demonstrated
brain and auditory system injuries,
hemorrhages, and congestion in
multiple organs, similar to the
pathological findings of the Bahamas
and Madeira stranding events. In
addition, the necropsy results of the
Canary Islands stranding event lead to
the hypothesis that the presence of
disseminated and widespread gas
bubbles and fat emboli were indicative
of nitrogen bubble formation, similar to
what might be expected in
decompression sickness (Jepson et al.,
2003; Ferna´ndez et al., 2005).
Hanalei Bay, Hawaii (2004)
On July 3 and 4, 2004, approximately
150 to 200 melon-headed whales
occupied the shallow waters of Hanalei
Bay, Kauai, Hawaii for over 28 hours.
Attendees of a canoe blessing observed
the animals entering the Bay in a single
wave formation at 7 a.m. on July 3,
2004. The animals were observed
moving back into the shore from the
mouth of the Bay at 9 a.m. The usually
pelagic animals milled in the shallow
bay and were returned to deeper water
with human assistance beginning at 9:30
a.m. on July 4, 2004, and were out of
sight by 10:30 a.m.
Only one animal, a calf, was known
to have died following this event. The
animal was noted alive and alone in the
Bay on the afternoon of July 4, 2004,
and was found dead in the Bay the
morning of July 5, 2004. A full
necropsy, magnetic resonance imaging,
and computerized tomography
examination were performed on the calf
to determine the manner and cause of
death. The combination of imaging,
necropsy, and histological analyses
found no evidence of infectious,
internal traumatic, congenital, or toxic
factors. Cause of death could not be
definitively determined, but it is likely
that maternal separation, poor
nutritional condition, and dehydration
contributed to the final demise of the
animal. Although it is not known when
the calf was separated from its mother,
the animals’ movement into the Bay and
subsequent milling and re-grouping may
have contributed to the separation or
lack of nursing, especially if the
maternal bond was weak or this was an
inexperienced mother with her first calf.
Environmental factors, abiotic and
biotic, were analyzed for any anomalous
occurrences that would have
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
contributed to the animals entering and
remaining in Hanalei Bay. The Bay’s
bathymetry is similar to many other
sites within the Hawaiian Island chain
and dissimilar to sites that have been
associated with mass strandings in other
parts of the United States. The weather
conditions appeared to be normal for
that time of year with no fronts or other
significant features noted. There was no
evidence of unusual distribution,
occurrence of predator or prey species,
or unusual harmful algal blooms,
although Mobley et al. (2007) suggested
that the full moon cycle that occurred at
that time may have influenced a run of
squid into the Bay. Weather patterns
and bathymetry that have been
associated with mass strandings
elsewhere were not found to occur in
this instance.
The Hanalei event was spatially and
temporally correlated with RIMPAC.
Official sonar training and tracking
exercises in the Pacific Missile Range
Facility (PMRF) warning area did not
commence until approximately 8 a.m.
on July 3 and were thus ruled out as a
possible trigger for the initial movement
into the Bay. However, six naval surface
vessels transiting to the operational area
on July 2 intermittently transmitted
active sonar (for approximately 9 hours
total from 1:15 p.m. to 12:30 a.m.) as
they approached from the south. The
potential for these transmissions to have
triggered the whales’ movement into
Hanalei Bay was investigated. Analyses
with the information available indicated
that animals to the south and east of
Kaua’i could have detected active sonar
transmissions on July 2, and reached
Hanalei Bay on or before 7 a.m. on July
3. However, data limitations regarding
the position of the whales prior to their
arrival in the Bay, the magnitude of
sonar exposure, behavioral responses of
melon-headed whales to acoustic
stimuli, and other possible relevant
factors preclude a conclusive finding
regarding the role of sonar in triggering
this event. Propagation modeling
suggests that transmissions from sonar
use during the July 3 exercise in the
PMRF warning area may have been
detectable at the mouth of the Bay. If the
animals responded negatively to these
signals, it may have contributed to their
continued presence in the Bay. The U.S.
Navy ceased all active sonar
transmissions during exercises in this
range on the afternoon of July 3.
Subsequent to the cessation of sonar
use, the animals were herded out of the
Bay.
While causation of this stranding
event may never be unequivocally
determined, NMFS considers the active
sonar transmissions of July 2–3, 2004, a
PO 00000
Frm 00041
Fmt 4701
Sfmt 4702
49695
plausible, if not likely, contributing
factor in what may have been a
confluence of events. This conclusion is
based on the following: (1) the evidently
anomalous nature of the stranding; (2)
its close spatiotemporal correlation with
wide-scale, sustained use of sonar
systems previously associated with
stranding of deep-diving marine
mammals; (3) the directed movement of
two groups of transmitting vessels
toward the southeast and southwest
coast of Kauai; (4) the results of acoustic
propagation modeling and an analysis of
possible animal transit times to the Bay;
and (5) the absence of any other
compelling causative explanation. The
initiation and persistence of this event
may have resulted from an interaction of
biological and physical factors. The
biological factors may have included the
presence of an apparently uncommon,
deep-diving cetacean species (and
possibly an offshore, non-resident
group), social interactions among the
animals before or after they entered the
Bay, and/or unknown predator or prey
conditions. The physical factors may
have included the presence of nearby
deep water, multiple vessels transiting
in a directed manner while transmitting
active sonar over a sustained period, the
presence of surface sound ducting
conditions, and/or intermittent and
random human interactions while the
animals were in the Bay.
A separate event involving melonheaded whales and rough-toothed
dolphins took place over the same
period of time in the Northern Mariana
Islands (Jefferson et al., 2006), which is
several thousand miles from Hawaii.
Some 500 to 700 melon-headed whales
came into Sasanhaya Bay on July 4,
2004, near the island of Rota and then
left of their own accord after 5.5 hours;
no known active sonar transmissions
occurred in the vicinity of that event.
The Rota incident led to scientific
debate regarding what, if any,
relationship the event had to the
simultaneous events in Hawaii and
whether they might be related by some
common factor (e.g., there was a full
moon on July 2, 2004, as well as during
other melon-headed whale strandings
and nearshore aggregations (Brownell et
al., 2009; Lignon et al., 2007; Mobley et
al., 2007). Brownell et al. (2009)
compared the two incidents, along with
one other stranding incident at Nuka
Hiva in French Polynesia and normal
resting behaviors observed at Palmyra
Island, in regard to physical features in
the areas, melon-headed whale
behavior, and lunar cycles. Brownell et
al., (2009) concluded that the rapid
entry of the whales into Hanalei Bay,
E:\FR\FM\11AUP2.SGM
11AUP2
49696
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
their movement into very shallow water
far from the 100-m contour, their
milling behavior (typical pre-stranding
behavior), and their reluctance to leave
the Bay constituted an unusual event
that was not similar to the events that
occurred at Rota, which appear to be
similar to observations of melon-headed
whales resting normally at Palmyra
Island. Additionally, there was no
correlation between lunar cycle and the
types of behaviors observed in the
Brownell et al. (2009) examples.
Spain (2006)
The Spanish Cetacean Society
reported an atypical mass stranding of
four beaked whales that occurred
January 26, 2006, on the southeast coast
of Spain, near Moja´car (Gulf of Vera) in
the Western Mediterranean Sea.
According to the report, two of the
whales were discovered the evening of
January 26 and were found to be still
alive. Two other whales were
discovered during the day on January
27, but had already died. The first three
animals were located near the town of
Moja´car and the fourth animal was
found dead, a few kilometers north of
the first three animals. From January
25–26, 2006, Standing NATO Response
Force Maritime Group Two (five of
seven ships including one U.S. ship
under NATO Operational Control) had
conducted active sonar training against
a Spanish submarine within 50 nmi (93
km) of the stranding site.
Veterinary pathologists necropsied
the two male and two female Cuvier’s
beaked whales. According to the
pathologists, the most likely primary
cause of this type of beaked whale mass
stranding event was anthropogenic
acoustic activities, most probably antisubmarine MFAS used during the
military naval exercises. However, no
positive acoustic link was established as
a direct cause of the stranding. Even
though no causal link can be made
between the stranding event and naval
exercises, certain conditions may have
existed in the exercise area that, in their
aggregate, may have contributed to the
marine mammal strandings (Freitas,
2004). Exercises were conducted in
areas of at least 547 fathoms (1,000 m)
depth near a shoreline where there is a
rapid change in bathymetry on the order
of 547 to 3,281 fathoms (1,000 to 6,000
m) occurring across a relatively short
horizontal distance (Freitas, 2004).
Multiple ships (in this instance, five)
were operating MFAS in the same area
over extended periods of time (in this
case, 20 hours) in close proximity; and
exercises took place in an area
surrounded by landmasses, or in an
embayment. Exercises involving
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
multiple ships employing MFAS near
land may have produced sound directed
towards a channel or embayment that
may have cut off the lines of egress for
the affected marine mammals (Freitas,
2004).
Behaviorally Mediated Responses to
MFAS That May Lead to Stranding
Although the confluence of Navy
MFAS with the other contributory
factors noted in the 2001 NMFS/Navy
joint report was identified as the cause
of the 2000 Bahamas stranding event,
the specific mechanisms that led to that
stranding (or the others) are not well
understood, and there is uncertainty
regarding the ordering of effects that led
to the stranding. It is unclear whether
beaked whales were directly injured by
sound (e.g., acoustically mediated
bubble growth, as addressed above)
prior to stranding or whether a
behavioral response to sound occurred
that ultimately caused the beaked
whales to be injured and strand.
Although causal relationships
between beaked whale stranding events
and active sonar remain unknown,
several authors have hypothesized that
stranding events involving these species
in the Bahamas and Canary Islands may
have been triggered when the whales
changed their dive behavior in a startled
response to exposure to active sonar or
to further avoid exposure (Cox et al.,
2006; Rommel et al., 2006). These
authors proposed three mechanisms by
which the behavioral responses of
beaked whales upon being exposed to
active sonar might result in a stranding
event. These include the following: gas
bubble formation caused by excessively
fast surfacing; remaining at the surface
too long when tissues are supersaturated
with nitrogen; or diving prematurely
when extended time at the surface is
necessary to eliminate excess nitrogen.
More specifically, beaked whales that
occur in deep waters that are in close
proximity to shallow waters (for
example, the ‘‘canyon areas’’ that are
cited in the Bahamas stranding event;
see D’Spain and D’Amico, 2006), may
respond to active sonar by swimming
into shallow waters to avoid further
exposures and strand if they were not
able to swim back to deeper waters.
Second, beaked whales exposed to
active sonar might alter their dive
behavior. Changes in their dive behavior
might cause them to remain at the
surface or at depth for extended periods
of time which could lead to hypoxia
directly by increasing their oxygen
demands or indirectly by increasing
their energy expenditures (to remain at
depth) and increase their oxygen
demands as a result. If beaked whales
PO 00000
Frm 00042
Fmt 4701
Sfmt 4702
are at depth when they detect a ping
from an active sonar transmission and
change their dive profile, this could lead
to the formation of significant gas
bubbles, which could damage multiple
organs or interfere with normal
physiological function (Cox et al., 2006;
Rommel et al., 2006; Zimmer and
Tyack, 2007). Baird et al. (2005) found
that slow ascent rates from deep dives
and long periods of time spent within
50 m of the surface were typical for both
Cuvier’s and Blainville’s beaked whales,
the two species involved in mass
strandings related to naval sonar. These
two behavioral mechanisms may be
necessary to purge excessive dissolved
nitrogen concentrated in their tissues
during their frequent long dives (Baird
et al., 2005). Baird et al. (2005) further
suggests that abnormally rapid ascents
or premature dives in response to highintensity sonar could indirectly result in
physical harm to the beaked whales,
through the mechanisms described
above (gas bubble formation or nonelimination of excess nitrogen). In a
review of the previously published data
on the potential impacts of sonar on
beaked whales, Bernaldo de Quiro´s et
al. (2019) suggested that the effect of
mid-frequency active sonar on beaked
whales varies among individuals or
populations, and that predisposing
conditions such as previous exposure to
sonar and individual health risk factors
may contribute to individual outcomes
(such as decompression sickness).
Because many species of marine
mammals make repetitive and
prolonged dives to great depths, it has
long been assumed that marine
mammals have evolved physiological
mechanisms to protect against the
effects of rapid and repeated
decompressions. Although several
investigators have identified
physiological adaptations that may
protect marine mammals against
nitrogen gas supersaturation (alveolar
collapse and elective circulation;
Kooyman et al., 1972; Ridgway and
Howard, 1979), Ridgway and Howard
(1979) reported that bottlenose dolphins
that were trained to dive repeatedly had
muscle tissues that were substantially
supersaturated with nitrogen gas.
Houser et al. (2001b) used these data to
model the accumulation of nitrogen gas
within the muscle tissue of other marine
mammal species and concluded that
cetaceans that dive deep and have slow
ascent or descent speeds would have
tissues that are more supersaturated
with nitrogen gas than other marine
mammals. Based on these data, Cox et
al. (2006) hypothesized that a critical
dive sequence might make beaked
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
whales more prone to stranding in
response to acoustic exposures. The
sequence began with (1) very deep (to
depths as deep as 2 km) and long (as
long as 90 minutes) foraging dives; (2)
relatively slow, controlled ascents; and
(3) a series of ‘‘bounce’’ dives between
100 and 400 m in depth (see also
Zimmer and Tyack, 2007). They
concluded that acoustic exposures that
disrupted any part of this dive sequence
(for example, causing beaked whales to
spend more time at surface without the
bounce dives that are necessary to
recover from the deep dive) could
produce excessive levels of nitrogen
supersaturation in their tissues, leading
to gas bubble and emboli formation that
produces pathologies similar to
decompression sickness.
Zimmer and Tyack (2007) modeled
nitrogen tension and bubble growth in
several tissue compartments for several
hypothetical dive profiles and
concluded that repetitive shallow dives
(defined as a dive where depth does not
exceed the depth of alveolar collapse,
approximately 72 m for Cuvier’s beaked
whale), perhaps as a consequence of an
extended avoidance reaction to sonar
sound, could pose a risk for
decompression sickness and that this
risk should increase with the duration
of the response. Their models also
suggested that unrealistically rapid rates
of ascent from normal dive behaviors
are unlikely to result in supersaturation
to the extent that bubble formation
would be expected. Tyack et al. (2006)
suggested that emboli observed in
animals exposed to mid-frequency range
sonar (Jepson et al., 2003; Fernandez et
al., 2005; Ferna´ndez et al., 2012) could
stem from a behavioral response that
involves repeated dives shallower than
the depth at which lung collapse occurs.
Given that nitrogen gas accumulation is
a passive process (i.e., nitrogen is
metabolically inert), a bottlenose
dolphin was trained to repetitively dive
a profile predicted to elevate nitrogen
saturation to the point that nitrogen
bubble formation was predicted to
occur. However, inspection of the
vascular system of the dolphin via
ultrasound did not demonstrate the
formation of asymptomatic nitrogen gas
bubbles (Houser et al., 2007). Baird et al.
(2008), in a beaked whale tagging study
off Hawaii, showed that deep dives are
equally common during day or night,
but ‘‘bounce dives’’ are typically a
daytime behavior, possibly associated
with visual predator avoidance. This
may indicate that ‘‘bounce dives’’ are
associated with something other than
behavioral regulation of dissolved
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
nitrogen levels, which would be
necessary day and night.
If marine mammals respond to a Navy
vessel that is transmitting active sonar
in the same way that they might
respond to a predator, their probability
of flight responses could increase when
they perceive that Navy vessels are
approaching them directly, because a
direct approach may convey detection
and intent to capture (Burger and
Gochfeld, 1981, 1990; Cooper, 1997,
1998). Please see the Flight Response
section of this proposed rule for
additional discussion.
Despite the many theories involving
bubble formation (both as a direct cause
of injury, see Acoustically-Induced
Bubble Formation Due to Sonars and
Other Pressure-related Injury section
and an indirect cause of stranding),
Southall et al. (2007) summarizes that
there is either scientific disagreement or
a lack of information regarding each of
the following important points: (1)
received acoustical exposure conditions
for animals involved in stranding
events; (2) pathological interpretation of
observed lesions in stranded marine
mammals; (3) acoustic exposure
conditions required to induce such
physical trauma directly; (4) whether
noise exposure may cause behavioral
reactions (such as atypical diving
behavior) that secondarily cause bubble
formation and tissue damage; and (5)
the extent the post mortem artifacts
introduced by decomposition before
sampling, handling, freezing, or
necropsy procedures affect
interpretation of observed lesions.
Strandings in the GOA Study Area
Stranded marine mammals are
reported along the entire western coast
of the United States each year. Marine
mammals strand due to natural or
anthropogenic causes; the majority of
reported type of occurrences in marine
mammal strandings in the Pacific
include fisheries interactions,
entanglement, vessel strike, and
predation (Carretta et al., 2019a; Carretta
et al., 2019b; Carretta et al., 2017a;
Helker et al., 2019; Helker et al., 2017;
NOAA, 2018, 2019). Stranding events
that are associated with active UMEs in
Alaska (inclusive of the GOA Study
Area) were previously discussed in the
Description of Marine Mammals and
Their Habitat in the Area of the
Specified Activities section.
In 2020, there were 65 confirmed
strandings reported in the Gulf of
Alaska (Savage, 2021). Of these
strandings, 43 were cetaceans; 20 of the
stranded cetaceans were gray whales,
which as discussed in the Description of
Marine Mammals and Their Habitat in
PO 00000
Frm 00043
Fmt 4701
Sfmt 4702
49697
the Area of the Specified Activities
section of this proposed rule, are
affected by a UME. Of the 2020
confirmed reports involving human
interaction, most reports indicated an
entanglement. Naval sonar has been
identified as a contributing factor in a
small number of strandings as discussed
above; however, none of these have
occurred in the GOA Study Area.
Potential Effects of Vessel Strike
Vessel collisions with marine
mammals, also referred to as vessel
strikes or ship strikes, can result in
death or serious injury of the animal.
Wounds resulting from ship strike may
include massive trauma, hemorrhaging,
broken bones, or propeller lacerations
(Knowlton and Kraus, 2001). An animal
at the surface could be struck directly by
a vessel, a surfacing animal could hit
the bottom of a vessel, or an animal just
below the surface could be cut by a
vessel’s propeller. Superficial strikes
may not kill or result in the death of the
animal. Lethal interactions are typically
associated with large whales, which are
occasionally found draped across the
bulbous bow of large commercial ships
upon arrival in port. Although smaller
cetaceans are more maneuverable in
relation to large vessels than are large
whales, as a general matter they may
also be susceptible to strike.
The most vulnerable marine mammals
are those that spend extended periods of
time at the surface in order to restore
oxygen levels within their tissues after
deep dives (e.g., the sperm whale). In
one recent case, an Australian naval
vessel struck both a mother fin whale
and calf off the coast of California. In
addition, some baleen whales seem
generally unresponsive to vessel sound,
making them more susceptible to vessel
collisions (Nowacek et al., 2004). These
species are primarily large, slow moving
whales. Marine mammal responses to
vessels may include avoidance and
changes in dive pattern (NRC, 2003).
Some researchers have suggested the
relative risk of a vessel strike can be
assessed as a function of animal density
and the magnitude of vessel traffic (e.g.,
Fonnesbeck et al., 2008; Vanderlaan et
al., 2008). Differences among vessel
types also influence the probability of a
vessel strike. The ability of any ship to
detect a marine mammal and avoid a
collision depends on a variety of factors,
including environmental conditions,
ship design, size, speed, and ability and
number of personnel observing, as well
as the behavior of the animal.
An examination of all known ship
strikes from all shipping sources
(civilian and military) indicates vessel
speed is a principal factor in whether a
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49698
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
vessel strike occurs and, if so, whether
it results in injury, serious injury, or
mortality (Knowlton and Kraus, 2001;
Laist et al., 2001; Jensen and Silber,
2003; Pace and Silber, 2005; Vanderlaan
and Taggart, 2007; Conn and Silber
2013). Impact forces increase with
speed, as does the probability of a strike
at a given distance (Silber et al., 2010;
Gende et al., 2011). For large vessels,
speed and angle of approach can
influence the severity of a strike. In
assessing records in which vessel speed
was known, Laist et al. (2001) found a
direct relationship between the
occurrence of a whale strike and the
speed of the vessel involved in the
collision. The authors concluded that
most deaths occurred when a vessel was
traveling in excess of 13 kn.
Jensen and Silber (2003) detailed 292
records of known or probable ship
strikes of all large whale species from
1975 to 2002. Of these, vessel speed at
the time of collision was reported for 58
cases. Of these 58 cases, 39 (or 67
percent) resulted in serious injury or
death (19 of those resulted in serious
injury as determined by blood in the
water, propeller gashes or severed
tailstock, and fractured skull, jaw,
vertebrae, hemorrhaging, massive
bruising or other injuries noted during
necropsy and 20 resulted in death).
Operating speeds of vessels that struck
various species of large whales ranged
from 2 to 51 kn. The majority (79
percent) of these strikes occurred at
speeds of 13 kn or greater. The average
speed that resulted in serious injury or
death was 18.6 kn. Pace and Silber
(2005) found that the probability of
death or serious injury increased rapidly
with increasing vessel speed.
Specifically, the predicted probability of
serious injury or death increased from
45 to 75 percent as vessel speed
increased from 10 to 14 kn, and
exceeded 90 percent at 17 kn. Higher
speeds during collisions result in greater
force of impact and also appear to
increase the chance of severe injuries or
death. While modeling studies have
suggested that hydrodynamic forces
pulling whales toward the vessel hull
increase with increasing speed (Clyne,
1999; Knowlton et al., 1995), this is
inconsistent with Silber et al. (2010),
which demonstrated that there is no
such relationship (i.e., hydrodynamic
forces are independent of speed).
In a separate study, Vanderlaan and
Taggart (2007) analyzed the probability
of lethal mortality of large whales at a
given speed, showing that the greatest
rate of change in the probability of a
lethal injury to a large whale as a
function of vessel speed occurs between
8.6 and 15 kn. The chances of a lethal
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
injury decline from approximately 80
percent at 15 kn to approximately 20
percent at 8.6 kn. At speeds below 11.8
kn, the chances of lethal injury drop
below 50 percent, while the probability
asymptotically increases toward 100
percent above 15 kn.
Large whales also do not have to be
at the water’s surface to be struck. Silber
et al. (2010) found when a whale is
below the surface (about one to two
times the vessel draft), there is likely to
be a pronounced propeller suction
effect. This suction effect may draw the
whale into the hull of the ship,
increasing the probability of propeller
strikes.
The Jensen and Silber (2003) report
notes that the Large Whale Ship Strike
Database represents a minimum number
of collisions, because the vast majority
probably goes undetected or unreported.
In contrast, Navy personnel are more
likely to detect any strike that does
occur because of the required personnel
training and Lookouts (as described in
the Proposed Mitigation Measures
section), and they are required to report
all ship strikes involving marine
mammals.
There are some key differences
between the operation of military and
non-military vessels, which make the
likelihood of a military vessel striking a
whale lower than some other vessels
(e.g., commercial merchant vessels),
although as noted above strikes by naval
vessels can occur. Key differences
include:
• many military ships have their
bridges positioned closer to the bow,
offering better visibility ahead of the
ship (compared to a commercial
merchant vessel);
• there are often aircraft associated
with the training activity (which can
serve as Lookouts), which can more
readily detect cetaceans in the vicinity
of a vessel or ahead of a vessel’s present
course before crew on the vessel would
be able to detect them;
• military ships are generally more
maneuverable than commercial
merchant vessels, and if cetaceans are
spotted in the path of the ship, could be
capable of changing course more
quickly;
• the crew size on military vessels is
generally larger than merchant ships,
allowing for stationing more trained
Lookouts on the bridge. At all times
when vessels are underway, trained
Lookouts and bridge navigation teams
are used to detect objects on the surface
of the water ahead of the ship, including
cetaceans. Additional Lookouts, beyond
those already stationed on the bridge
and on navigation teams, are positioned
PO 00000
Frm 00044
Fmt 4701
Sfmt 4702
as Lookouts during some training
events; and
• when submerged, submarines are
generally slow moving (to avoid
detection) and therefore marine
mammals at depth with a submarine are
likely able to avoid collision with the
submarine. When a submarine is
transiting on the surface, there are
Lookouts serving the same function as
they do on surface ships.
In the GOA Study Area, NMFS and
the Navy have no documented vessel
strikes of marine mammals by the Navy.
Therefore, NMFS has not used the
quantitative approach to assess the
likelihood of vessel strikes used in the
Phase III incidental take rulemakings for
Navy activities in the Atlantic Fleet
Training and Testing (AFTT) and
Hawaii-Southern California Training
and Testing (HSTT) Study Areas, which
starts with the number of Navy strikes
that have occurred in the study area in
question. But based on this lack of
strikes and other factors described
below, which the Navy presented and
NMFS agrees are appropriate factors to
consider in assessing the likelihood of
ship strike, the Navy does not anticipate
vessel strikes and has not requested
authorization to take marine mammals
by serious injury or mortality within the
GOA Study Area during training
activities. Based on consideration of all
pertinent information, including, as
appropriate, information on ship strikes
in other Navy study areas, NMFS agrees
with the Navy’s conclusion based on the
analysis and other factors described
below.
Within Alaska waters, there were 28
reported marine mammal vessel strikes
between 2013 and 2017 (none of which
were from U.S. Navy vessels) (Delean et
al., 2020), which is a primary
consideration in the evaluation of the
likelihood that a strike by U.S. Navy
vessels would occur in the GOA Study
Area in the next 7 years. Though not in
the same region, and noting the larger
scale and differences in types of
activities that occur there, NMFS also
considered the incidents of two
accidental ship strikes of large whales
by U.S. Navy vessels in the HSTT Study
Area that occurred in June 2021 and
July 2021 (the first U.S. Navy ship
strikes in the HSTT Study Area since
2009). The two ship strikes were of large
whales, but in both cases, the whale’s
species could not be determined.
Appropriately, as indicated in the
Navy’s 2022 application (87 FR 33113;
June 1, 2022) to revise the 2020 HSTT
regulations (50 CFR part 218, subpart H)
and LOAs, and as has been the practice
in NMFS analyses for all major Navy
training and testing rules, those strikes
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
would be quantitatively incorporated
into the prediction of future strikes in
that region. However, due to differences
across regions, both in the density and
occurrence of marine mammals, the
levels and types of activities, and other
environmental factors—all of which
contribute to differences in the
historical strikes in a given region—
strikes that occur in the HSTT Study
Area are not quantitatively considered
in strike predictions for the GOA Study
Area.
More broadly regarding the likelihood
of strikes from U.S. Navy vessels, large
Navy vessels (greater than 18 m in
length) within the offshore areas of
range complexes operate differently
from commercial vessels in ways that
still likely reduce potential whale
collisions. Surface ships operated by or
for the Navy have multiple personnel
assigned to stand watch at all times
when a ship or surfaced submarine is
moving through the water (underway).
A primary duty of personnel standing
watch on surface ships is to detect and
report all objects and disturbances
sighted in the water that may indicate
a threat to the vessel and its crew, such
as debris, a periscope, surfaced
submarine, or surface disturbance. Per
vessel safety requirements, personnel
standing watch also report any marine
mammals sighted in the path of the
vessel as a standard collision avoidance
procedure. All vessels proceed at a safe
speed so they can take proper and
effective action to avoid a collision with
any sighted object or disturbance, and
can be stopped within a distance
appropriate to the prevailing
circumstances and conditions.
Between 2007 and 2009, the Navy
developed and distributed additional
training, mitigation, and reporting tools
to Navy operators to improve marine
mammal protection and to ensure
compliance with LOA requirements. In
2009, the Navy implemented Marine
Species Awareness Training designed to
improve effectiveness of visual
observation for marine resources,
including marine mammals.
Additionally, for over a decade, the
Navy has implemented the Protective
Measures Assessment Protocol software
tool, which provides operators with
notification of the required mitigation
and a visual display of the planned
training or testing activity location
overlaid with relevant environmental
data.
Furthermore, specific to the Navy’s
proposed activities in the GOA Study
Area, the training activities would occur
over a maximum of 21 days annually
over a large area within the Gulf of
Alaska, in comparison to Navy activities
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
that occur 365 days-per-year in other
Study Areas. The GOA Study Area
activities would include one Carrier
Strike Group, which the Navy indicates
would include up to six surface vessels
(though in some cases there could be
more vessels, and in some cases there
could be fewer). Therefore, the Navy’s
activities in the GOA Study Area would
include an estimated 126 at-sea days (6
vessels × 21 days) annually. This level
of potential Navy vessel activity is far
lower than vessel activity in other Study
Areas. The estimated number of at-sea
days for Navy training activities in the
GOA Study Area is approximately 1/4th
of that associated with Navy training
and testing in the Mariana Islands
Training and Testing (MITT) Study Area
(where vessel strike is also not
anticipated and has not occurred) over
the same time period, and
approximately 1/36th of that associated
with Navy training and testing in the
Hawaii-Southern California Training
and Testing (HSTT) Study Area (where
limited vessel strike is authorized) over
the same time period. In addition to
vessel strikes of large whales being
unlikely to occur for the reasons
explained, the Navy would implement
certain additional mitigation measures
that would reduce the chance of a vessel
strike even further. See the Proposed
Mitigation Measures section for more
details.
Based on all of these considerations,
NMFS has preliminarily determined
that the Navy’s decision not to request
incidental take authorization for vessel
strike of large whales is reasonable and
supported by multiple factors, including
the lack of ship strike reports in recent
(2013–2017) stranding records for
Alaska waters (including no strikes by
Navy vessels in the GOA Study Area;
Delean et al., 2020), the relatively small
numbers of Navy vessels across a large
expanse of offshore waters in the GOA
Study Area, the relatively short activity
period in which Navy vessels would
operate (maximum of 21 days per year),
and the procedural mitigation measures
that would be in place to further
minimize the potential for vessel strike.
In addition to the reasons listed above
that make it unlikely that the Navy
would hit a large whale (more
maneuverable ships, larger crew, etc.),
the following are additional reasons that
vessel strike of dolphins, small whales,
and pinnipeds is very unlikely. Dating
back more than 20 years and for as long
as it has kept records, the Navy has no
records of any small whales or
pinnipeds being struck by a vessel as a
result of Navy activities. Over the same
time period, NMFS and the Navy have
only one record of a dolphin being
PO 00000
Frm 00045
Fmt 4701
Sfmt 4702
49699
struck by a vessel as a result of Navy
activities. The dolphin was accidentally
struck by a Navy small boat in fall 2021
in Saint Andrew’s Pass, Florida. The
smaller size and maneuverability of
dolphins, small whales, and pinnipeds
generally make such strikes very
unlikely. Other than this one reported
strike of a dolphin in 2021, NMFS has
never received any reports from other
LOA or Incidental Harassment
Authorization holders indicating that
these species have been struck by
vessels. In addition, worldwide ship
strike records show little evidence of
strikes of these groups from the
shipping sector and larger vessels, and
the majority of the Navy’s activities
involving faster-moving vessels (that
could be considered more likely to hit
a marine mammal) are located in
offshore areas where smaller delphinid
densities are lower. The majority of the
GOA Study Area is located offshore of
the continental slope. While the Navy’s
specified activities in the GOA Study
Area do involve the use of small boats
also, use of small boats would occur on
no more than 21 days per year, the
length of the Navy’s proposed training
exercise. Based on this information,
NMFS concurs with the Navy’s
assessment that vessel strike is not
likely to occur for either large whales or
smaller marine mammals.
Marine Mammal Habitat
The Navy’s proposed training
activities could potentially affect marine
mammal habitat through the
introduction of impacts to the prey
species of marine mammals, acoustic
habitat (sound in the water column),
water quality, and biologically
important habitat for marine mammals.
Each of these potential effects was
considered in the 2020 GOA DSEIS/
OEIS and 2022 Supplement to the 2020
GOA DSEIS/OEIS, and based on the
information below and the supporting
information included in the 2020 GOA
DSEIS/OEIS, NMFS has preliminarily
determined that the proposed training
activities would not have adverse or
long-term impacts on marine mammal
habitat that would be expected to affect
the reproduction or survival of any
marine mammals.
Effects to Prey
Sound may affect marine mammals
through impacts on the abundance,
behavior, or distribution of prey species
(e.g., crustaceans, cephalopods, fish,
zooplankton). Marine mammal prey
varies by species, season, and location
and, for some species, is not well
documented. Here, we describe studies
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49700
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
regarding the effects of noise on known
marine mammal prey.
Fish utilize the soundscape and
components of sound in their
environment to perform important
functions such as foraging, predator
avoidance, mating, and spawning (e.g.,
Zelick et al., 1999; Fay, 2009). The most
likely effects on fishes exposed to loud,
intermittent, low-frequency sounds are
behavioral responses (i.e., flight or
avoidance). Short duration, sharp
sounds (such as pile driving or air guns)
can cause overt or subtle changes in fish
behavior and local distribution. The
reaction of fish to acoustic sources
depends on the physiological state of
the fish, past exposures, motivation
(e.g., feeding, spawning, migration), and
other environmental factors. Key
impacts to fishes may include
behavioral responses, hearing damage,
barotrauma (pressure-related injuries),
and mortality.
Fishes, like other vertebrates, have a
variety of different sensory systems to
glean information from the ocean
around them (Astrup and Mohl, 1993;
Astrup, 1999; Braun and Grande, 2008;
Carroll et al., 2017; Hawkins and
Johnstone, 1978; Ladich and Popper,
2004; Ladich and Schulz-Mirbach, 2016;
Mann, 2016; Nedwell et al., 2004;
Popper et al., 2003; Popper et al., 2005).
Depending on their hearing anatomy
and peripheral sensory structures,
which vary among species, fishes hear
sounds using pressure and particle
motion sensitivity capabilities and
detect the motion of surrounding water
(Fay et al., 2008) (terrestrial vertebrates
generally only detect pressure). Most
marine fishes primarily detect particle
motion using the inner ear and lateral
line system, while some fishes possess
additional morphological adaptations or
specializations that can enhance their
sensitivity to sound pressure, such as a
gas-filled swim bladder (Braun and
Grande, 2008; Popper and Fay, 2011).
Hearing capabilities vary considerably
between different fish species with data
only available for just over 100 species
out of the 34,000 marine and freshwater
fish species (Eschmeyer and Fong,
2016). In order to better understand
acoustic impacts on fishes, fish hearing
groups are defined by species that
possess a similar continuum of
anatomical features which result in
varying degrees of hearing sensitivity
(Popper and Hastings, 2009a). There are
four hearing groups defined for all fish
species (modified from Popper et al.,
2014) within this analysis and they
include: fishes without a swim bladder
(e.g., flatfish, sharks, rays, etc.); fishes
with a swim bladder not involved in
hearing (e.g., salmon, cod, pollock, etc.);
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
fishes with a swim bladder involved in
hearing (e.g., sardines, anchovy, herring,
etc.); and fishes with a swim bladder
involved in hearing and high-frequency
hearing (e.g., shad and menhaden).
In terms of behavioral responses,
Juanes et al. (2017) discuss the potential
for negative impacts from anthropogenic
soundscapes on fish, but the author’s
focus was on broader based sounds such
as ship and boat noise sources. There
are no detonations of explosives
occurring underwater in the specified
activity for this rulemaking, and
occasional behavioral reactions to
intermittent explosions occurring in-air
at or above the water surface are
unlikely to cause long-term
consequences for individual fish or
populations. Fish that experience
hearing loss as a result of exposure to
explosions may have a reduced ability
to detect relevant sounds such as
predators, prey, or social vocalizations.
However, PTS has not been known to
occur in fishes, and any hearing loss in
fish may be as temporary as the
timeframe required to repair or replace
the sensory cells that were damaged or
destroyed (Popper et al., 2014; Popper et
al., 2005; Smith et al., 2006). It is not
known if damage to auditory nerve
fibers could occur and, if so, whether
fibers would recover during this
process. It is also possible for fish to be
injured or killed by an explosion in the
immediate vicinity of the surface from
dropped or fired ordnance. Physical
effects from pressure waves generated
by in-air detonations at or above the
water surface could potentially affect
fish within proximity of training
activities. The shock wave from an
explosion occurring at or above the
water surface may be lethal to fish at
close range, causing massive organ and
tissue damage and internal bleeding
(Keevin and Hempen, 1997). At greater
distance from the detonation point, the
extent of mortality or injury depends on
a number of factors, including fish size,
body shape, orientation, and species
(Keevin and Hempen, 1997; Wright,
1982). At the same distance from the
source, larger fish are generally less
susceptible to death or injury, elongated
forms that are round in cross-section are
less at risk than deep-bodied forms, and
fish oriented sideways to the blast suffer
the greatest impact (Edds-Walton and
Finneran, 2006; O’Keeffe, 1984;
O’Keeffe and Young, 1984; Wiley et al.,
1981; Yelverton et al., 1975). Species
with gas-filled organs have a higher
potential for mortality than those
without them (Gaspin, 1975; Gaspin et
al., 1976; Goertner et al., 1994).
Nonetheless, Navy activities involving
in-air explosions at or above the water
PO 00000
Frm 00046
Fmt 4701
Sfmt 4702
surface are dispersed in space and time;
therefore, repeated exposure of
individual fishes is unlikely. Mortality
and injury effects to fishes from
explosives would be localized around
the area of a given explosion at or above
the water surface, but only if individual
fish and the explosive (and immediate
pressure field) were co-located at the
same time. Fishes deeper in the water
column or on the bottom would not be
affected by water surface explosions.
Repeated exposure of individual fish to
sound and energy from Navy events
involving in-air detonations at or above
the water surface is not likely given fish
movement patterns, especially
schooling prey species. Most acoustic
effects, if any, are expected to be short
term and localized. Long-term
consequences for fish populations,
including key prey species within the
GOA Study Area, would not be
expected.
Vessels and surface targets do not
normally collide with adult fish, most of
which can detect and avoid them.
Exposure of fishes to vessel strike
stressors is limited to those fish groups
that are large, slow moving, and may
occur near the surface, such as basking
sharks, which are not marine mammal
prey species. Vessel strikes would not
pose a risk to most of the other marine
fish groups, because many fish can
detect and avoid vessel movements,
making strikes extremely unlikely and
allowing the fish to return to their
normal behavior after the ship or device
passes. As a vessel approaches a fish, it
could have a detectable behavioral or
physiological response (e.g., swimming
away and increased heart rate) as the
passing vessel displaces it. However,
such reactions are not expected to have
effects on the survival, growth,
recruitment, or reproduction of these
marine fish groups at the population
level.
In addition to fish, prey sources such
as marine invertebrates could
potentially be impacted by sound
stressors as a result of the planned
activities. Data on response of
invertebrates such as squid has been
documented (de Soto, 2016; Sole et al.,
2017). Sole et al. (2017) reported
physiological injuries to cuttlefish in
cages placed at sea when exposed
during a controlled exposure
experiment to low-frequency sources
(315 Hz, 139–142 dB re 1 mPa2 and 400
Hz, 139–141 dB re 1 mPa2). Fewtrell and
McCauley (2012) reported squids
maintained in cages displayed startle
responses and behavioral changes when
exposed to seismic air gun sonar (136–
162 re 1 mPa2-s). However, the sources
Sole et al. (2017) and Fewtrell and
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
McCauley (2012) used are not similar
and are much lower frequency than
typical Navy sources or those included
in the Specified Activity within the
GOA Study Area. Nor do the studies
address the issue of individual
displacement outside of a zone of
impact when exposed to sound. Squids,
like most fish species, are likely more
sensitive to low-frequency sounds, and
may not perceive mid- and highfrequency sonars such as Navy sonars.
As with fish, cumulatively individual
and population-level impacts from
exposure to Navy sonar and explosives
for squid are not anticipated, and
explosive impacts would be short term,
localized, and likely to be
inconsequential to invertebrate
populations.
Explosions could kill or injure other
nearby marine invertebrates. Vessels
also have the potential to impact marine
invertebrates by disturbing the water
column or sediments, or directly
striking organisms (Bishop, 2008). The
propeller wash (water displaced by
propellers used for propulsion) from
vessel movement and water displaced
from vessel hulls can potentially disturb
marine invertebrates in the water
column and is a likely cause of
zooplankton mortality (Bickel et al.,
2011). The localized and short-term
exposure to explosions or vessels could
displace, injure, or kill zooplankton,
invertebrate eggs or larvae, and macroinvertebrates. However, mortality or
long-term consequences for a few
animals is unlikely to have measurable
effects on overall stocks or populations.
Long-term consequences to marine
invertebrate populations would not be
expected as a result of exposure to
sounds or vessels in the GOA Study
Area.
Military expended materials resulting
from training could potentially result in
minor long term changes to benthic
habitat. Military expended materials
may be colonized over time by benthic
organisms that prefer hard substrate and
would provide structure that could
attract some species of fish or
invertebrates. Overall, the combined
impacts of sound exposure, explosions,
vessel strikes, and military expended
materials resulting from the specified
activity would not be expected to have
measurable effects on populations of
marine mammal prey species and
marine mammal habitat.
Acoustic Habitat
Acoustic habitat is the soundscape
which encompasses all of the sound
present in a particular location and
time, as a whole when considered from
the perspective of the animals
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
experiencing it. Animals produce sound
for, or listen for sounds produced by,
conspecifics (communication during
feeding, mating, and other social
activities), other animals (finding prey
or avoiding predators), and the physical
environment (finding suitable habitats,
navigating). Together, sounds made by
animals and the geophysical
environment (e.g., produced by
earthquakes, lightning, wind, rain,
waves) make up the natural
contributions to the total acoustics of a
place. These acoustic conditions,
termed acoustic habitat, are one
attribute of an animal’s total habitat.
Soundscapes are also defined by, and
acoustic habitat influenced by, the total
contribution of anthropogenic sound.
This may include incidental emissions
from sources such as vessel traffic or
may be intentionally introduced to the
marine environment for data acquisition
purposes (as in the use of air gun arrays)
or for Navy training purposes (as in the
use of sonar and other acoustic sources).
Anthropogenic noise varies widely in its
frequency, content, duration, and
loudness, and these characteristics
greatly influence the potential habitatmediated effects to marine mammals
(please also see the previous discussion
on ‘‘Masking’’), which may range from
local effects for brief periods of time to
chronic effects over large areas and for
longer durations. Depending on the
extent of effects to habitat, animals may
alter their communications signals
(thereby potentially expending
additional energy) or miss acoustic cues
(either conspecific or adventitious).
Problems arising from a failure to detect
cues are more likely to occur when
noise stimuli are chronic and overlap
with biologically relevant cues used for
communication, orientation, and
predator/prey detection (Francis and
Barber, 2013). For more detail on these
concepts see, e.g., Barber et al., 2009;
Pijanowski et al., 2011; Francis and
Barber, 2013; Lillis et al., 2014, Hatch et
al., 2016; Duarte et al., 2021).
The term ‘‘listening area’’ refers to the
region of ocean over which sources of
sound can be detected by an animal at
the center of the space. Loss of
communication space concerns the area
over which a specific animal signal
(used to communicate with conspecifics
in biologically important contexts such
as foraging or mating) can be heard, in
noisier relative to quieter conditions
(Clark et al., 2009). Lost listening area
concerns the more generalized
contraction of the range over which
animals would be able to detect a
variety of signals of biological
importance, including eavesdropping on
predators and prey (Barber et al., 2009).
PO 00000
Frm 00047
Fmt 4701
Sfmt 4702
49701
Such metrics do not, in and of
themselves, document fitness
consequences for the marine animals
that live in chronically noisy
environments. Long-term populationlevel consequences mediated through
changes in the ultimate survival and
reproductive success of individuals are
difficult to study, and particularly so
underwater. However, it is increasingly
well documented that aquatic species
rely on qualities of natural acoustic
habitats, with researchers quantifying
reduced detection of important
ecological cues (e.g., Francis and Barber,
2013; Slabbekoorn et al., 2010) as well
as survivorship consequences in several
species (e.g., Simpson et al., 2014;
Nedelec et al., 2015).
The sounds produced during Navy
training activities can be widely
dispersed or concentrated in small areas
for varying periods. Sound produced
from training activities in the GOA
Study Area is temporary and limited to
a 21 consecutive day period from April
to October, unlike other Navy Study
Areas where training occurs year-round.
Any anthropogenic noise attributed to
training activities in the GOA Study
Area would be temporary and the
affected area would be expected to
immediately return to the original state
when these activities cease.
Water Quality
The 2011 GOA EIS/OEIS analyzed the
potential effects on water quality from
explosives, explosive byproducts, and
military expended materials including
their associated component metals and
chemicals. This analysis remains
accurate and complete, and is
incorporated by reference in the 2016
GOA SEIS/OEIS and 2020 GOA DSEIS/
OEIS. NMFS has reviewed this analysis
and concurs that it reflects the best
available science. High order explosions
consume most of the explosive material,
creating typical combustion products.
For example, in the case of Royal
Demolition Explosive, 98 percent of the
products are common seawater
constituents and the remainder is
rapidly diluted below levels that would
be expected to affect marine mammals.
Explosion byproducts associated with
high order detonations present no
secondary stressors to marine mammals
through sediment or water. However,
low order detonations and unexploded
ordnance present a potential for
exposure, but only in the immediate
vicinity of the ordnance. Degradation
products of Royal Demolition Explosive
are not toxic to marine organisms at
realistic exposure levels (Carniel et al.,
2019; Rosen and Lotufo, 2010) and any
remnant undetonated components from
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49702
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
explosives such as TNT, royal
demolition explosive, and high melting
explosive experience rapid biological
and photochemical degradation in
marine systems (Carniel et al., 2019;
Cruz-Uribe et al., 2007; Juhasz and
Naidu, 2007; Pavlostathis and Jackson,
2002; Singh et al., 2009; Walker et al.,
2006).
The findings from multiple studies
indicate the relatively low solubility of
most explosives and their degradation
products, metals, and chemicals
meaning that concentrations of these
contaminants in the marine
environment, including those associated
with either high-order or low-order
detonations, are relatively low and
readily diluted. A series of studies of a
World War II dump site off Hawaii have
demonstrated that only minimal
concentrations of degradation products
were detected in the adjacent sediments
and that there was no detectable uptake
in sampled organisms living on or in
proximity to the site (Briggs et al., 2016;
Carniel et al., 2019; Edwards et al.,
2016; Hawaii Undersea Military
Munitions Assessment, 2010; Kelley et
al., 2016; Koide et al., 2016). In the GOA
Study Area, the concentration of
unexploded ordnance, explosion
byproducts, metals, and other chemicals
would never exceed that of a World War
II dump site. As another example, the
Canadian Forces Maritime Experimental
and Test Ranges near Nanoose, British
Columbia, began operating in 1965
conducting test events for both U.S. and
Canadian forces, which included some
of the same activities proposed for the
GOA Study Area. Environmental
analyses of the impacts from military
expended materials at Nanoose were
documented in 1996 and 2005. The
analyses concluded the Navy test
activities ‘‘. . . had limited and perhaps
negligible effects on the natural
environment’’ (Environmental Science
Advisory Committee, 2005). Based on
these and other similar applicable
findings from multiple Navy ranges, and
based on the analysis in Section 3.3
(Water Resources) of the 2011 GOA
Final SEIS/OEIS (incorporated by
reference in the 2020 GOA Draft EIS/
OEIS), indirect impacts on marine
mammals from the training activities in
the GOA Study Area would be
negligible and would have no long-term
effect on habitat.
Equipment used by the Navy within
the GOA Study Area, including ships
and other marine vessels, aircraft, and
other equipment, are also potential
sources of by-products. All equipment is
properly maintained in accordance with
applicable Navy and legal requirements.
All such operating equipment meets
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
Federal water quality standards, where
applicable.
Estimated Take of Marine Mammals
This section indicates the number of
takes that NMFS is proposing to
authorize, which are based on the
maximum amount of take that NMFS
anticipates is reasonably likely to occur.
NMFS coordinated closely with the
Navy in the development of their
incidental take application, and
preliminarily agrees that the methods
the Navy has put forth described herein
to estimate take (including the model,
thresholds, and density estimates), and
the resulting numbers are based on the
best available science and appropriate
for authorization.
Takes would be in the form of
harassment only. For a military
readiness activity, the MMPA defines
‘‘harassment’’ as (i) Any act that injures
or has the significant potential to injure
a marine mammal or marine mammal
stock in the wild (Level A Harassment);
or (ii) Any act that disturbs or is likely
to disturb a marine mammal or marine
mammal stock in the wild by causing
disruption of natural behavioral
patterns, including, but not limited to,
migration, surfacing, nursing, breeding,
feeding, or sheltering, to a point where
such behavioral patterns are abandoned
or significantly altered (Level B
Harassment).
Proposed authorized takes would
primarily be in the form of Level B
harassment, as use of the acoustic and
explosive sources (i.e., sonar and
explosives) is most likely to result in the
disruption of natural behavioral patterns
to a point where they are abandoned or
significantly altered (as defined
specifically at the beginning of this
section, but referred to generally as
behavioral disturbance) or TTS for
marine mammals. There is also the
potential for Level A harassment, in the
form of auditory injury that results from
exposure to the sound sources utilized
in training activities.
Generally speaking, for acoustic
impacts NMFS estimates the amount
and type of harassment by considering:
(1) acoustic thresholds above which
NMFS believes the best available
science indicates marine mammals
would experience behavioral
disturbance or incur some degree of
temporary or permanent hearing
impairment; (2) the area or volume of
water that would be ensonified above
these levels in a day or event; (3) the
density or occurrence of marine
mammals within these ensonified areas;
and (4) the number of days of activities
or events.
PO 00000
Frm 00048
Fmt 4701
Sfmt 4702
Acoustic Thresholds
Using the best available science,
NMFS, in coordination with the Navy,
has established acoustic thresholds that
identify the most appropriate received
level of underwater sound above which
marine mammals exposed to these
sound sources could be reasonably
expected to experience a disruption in
behavior patterns to a point where they
are abandoned or significantly altered
(equated to onset of Level B
harassment), or to incur TTS onset
(equated to Level B harassment) or PTS
onset (equated to Level A harassment).
Thresholds have also been developed to
identify the pressure and impulse levels
above which animals may incur nonauditory injury or mortality from
exposure to explosive detonations
(although no non-auditory injury from
explosives is anticipated as part of this
rulemaking).
Despite the rapidly evolving science,
there are still challenges in quantifying
expected behavioral responses that
qualify as take by Level B harassment,
especially where the goal is to use one
or two predictable indicators (e.g.,
received level and distance) to predict
responses that are also driven by
additional factors that cannot be easily
incorporated into the thresholds (e.g.,
context). So, while the thresholds that
identify Level B harassment by
behavioral disturbance (referred to as
‘‘behavioral harassment thresholds’’)
have been refined to better consider the
best available science (e.g.,
incorporating both received level and
distance), they also still have some
built-in conservative factors to address
the challenge noted. For example, while
duration of observed responses in the
data are now considered in the
thresholds, some of the responses that
are informing take thresholds are of a
very short duration, such that it is
possible some of these responses might
not always rise to the level of disrupting
behavior patterns to a point where they
are abandoned or significantly altered.
We describe the application of this
behavioral harassment threshold as
identifying the maximum number of
instances in which marine mammals
could be reasonably expected to
experience a disruption in behavior
patterns to a point where they are
abandoned or significantly altered. In
summary, we believe these behavioral
harassment thresholds are the most
appropriate method for predicting Level
B harassment by behavioral disturbance
given the best available science and the
associated uncertainty.
E:\FR\FM\11AUP2.SGM
11AUP2
49703
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
Hearing Impairment (TTS/PTS) and
Non-Auditory Tissue Damage and
Mortality
NMFS’ Acoustic Technical Guidance
(NMFS, 2018) identifies dual criteria to
assess auditory injury (Level A
harassment) to five different marine
mammal groups (based on hearing
sensitivity) as a result of exposure to
noise from two different types of
sources (impulsive or non-impulsive).
The Acoustic Technical Guidance also
identifies criteria to predict TTS, which
is not considered injury and falls into
the Level B harassment category. The
Navy’s planned activity includes the use
of non-impulsive (sonar) and impulsive
(explosives) sources.
These thresholds (Table 5 and Table
6) were developed by compiling and
synthesizing the best available science
and soliciting input multiple times from
both the public and peer reviewers. The
references, analysis, and methodology
used in the development of the
thresholds are described in Acoustic
Technical Guidance, which may be
accessed at: https://www.fisheries.
noaa.gov/national/marine-mammalprotection/marine-mammal-acoustictechnical-guidance.
TABLE 5—ACOUSTIC THRESHOLDS IDENTIFYING THE ONSET OF TTS AND PTS FOR NON-IMPULSIVE SOUND SOURCES BY
FUNCTIONAL HEARING GROUPS
Non-impulsive
Functional hearing group
TTS threshold
SEL
(weighted)
PTS threshold
SEL
(weighted)
179
178
153
181
199
199
198
173
201
219
Low-Frequency Cetaceans ......................................................................................................................................
Mid-Frequency Cetaceans .......................................................................................................................................
High-Frequency Cetaceans .....................................................................................................................................
Phocid Pinnipeds (Underwater) ...............................................................................................................................
Otarid Pinnipeds (Underwater) ................................................................................................................................
Note: SEL thresholds in dB re: 1 μPa2-s accumulated over a 24-hr period.
Based on the best available science,
the Navy (in coordination with NMFS)
used the acoustic and pressure
thresholds indicated in Table 6 to
predict the onset of TTS, PTS, nonauditory tissue damage, and mortality
for explosives (impulsive) and other
impulsive sound sources.
TABLE 6—THRESHOLDS FOR TTS, PTS, NON-AUDITORY TISSUE DAMAGE, AND MORTALITY THRESHOLDS FOR MARINE
MAMMALS FOR EXPLOSIVES
Functional hearing group
Species
Low-frequency cetaceans
All mysticetes ................
Mid-frequency cetaceans
Most delphinids, medium
and large toothed
whales.
Porpoises and Kogia
spp.
Harbor seal, Hawaiian
monk seal, Northern
elephant seal.
California sea lion, Guadalupe fur seal, Northern fur seal.
High-frequency cetaceans
Phocidae ..........................
Otariidae ..........................
Weighted onset TTS 1
Weighted onset PTS
168 dB SEL or 213 dB
Peak SPL.
170 dB SEL or 224 dB
Peak SPL.
183 dB SEL or 219 dB
Peak SPL.
185 dB SEL or 230 dB
Peak SPL.
243 dB Peak SPL ..........
140 dB SEL or 196 dB
Peak SPL.
170 dB SEL or 212 dB
Peak SPL.
155 dB SEL or 202 dB
Peak SPL.
185 dB SEL or 218 dB
Peak SPL.
243 dB Peak SPL.
188 dB SEL or 226 dB
Peak SPL.
203 dB SEL or 232 dB
Peak SPL.
243 dB Peak SPL.
Slight GI tract injury
Slight lung
injury
Equation 1.
Mortality
Equation 2.
243 dB Peak SPL.
243 dB Peak SPL.
lotter on DSK11XQN23PROD with PROPOSALS2
Notes:
Equation 1: 47.5M1/3 (1+[DRm/10.1])1/6 Pa-sec.
Equation 2: 103M1/3 (1+[DRm/10.1])1/6 Pa-sec.
M = mass of the animals in kg.
DRm = depth of the receiver (animal) in meters.
SPL = sound pressure level.
Weighted SEL thresholds in dB re: 1 μPa2-s accumulated over a 24-h period.
1 Peak thresholds are unweighted.
The criteria used to assess the onset
of TTS and PTS due to exposure to
sonars (non-impulsive, see Table 5
above) are discussed further in the
Navy’s rulemaking/LOA application
(see Hearing Loss from Sonar and Other
Transducers in Chapter 6, Section
6.4.2.1, Methods for Analyzing Impacts
from Sonars and Other Transducers).
Refer to the Criteria and Thresholds for
U.S. Navy Acoustic and Explosive
Effects Analysis (Phase III) report (U.S.
Department of the Navy, 2017c) for
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
detailed information on how the criteria
and thresholds were derived, and to
Section 3.8.3.1.1.2 of the 2020 GOA
DSEIS/OEIS for a review of TTS
research published following
development of the criteria and
thresholds applied in the Navy’s
analysis and in NMFS’ Acoustic
Technical Guidance. Further, since
publication of the 2020 GOA DSEIS/
OEIS, several additional studies
associated with TTS in harbor porpoises
and seals have been published (e.g.,
PO 00000
Frm 00049
Fmt 4701
Sfmt 4702
Kastelein et al., 2020d; Kastelein et al.,
2021a and 2021b; Sills et al., 2020).
NMFS is aware of these recent papers
and is currently working with the Navy
to update NMFS’ Technical Guidance
for Assessing the Effects of
Anthropogenic Sound on Marine
Mammal Hearing Version 2.0 (Acoustic
Technical Guidance; NMFS 2018) to
reflect relevant papers that have been
published since the 2018 update on our
3–5 year update schedule in the
Acoustic Technical Guidance. First, we
E:\FR\FM\11AUP2.SGM
11AUP2
49704
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
note that the recent peer-reviewed
updated marine mammal noise
exposure criteria by Southall et al.
(2019a) provide identical PTS and TTS
thresholds and weighting functions to
those provided in NMFS’ Acoustic
Technical Guidance.
NMFS will continue to review and
evaluate new relevant data as it becomes
available and consider the impacts of
those studies on the Acoustic Technical
Guidance to determine what revisions/
updates may be appropriate. However,
any such revisions must undergo peer
and public review before being adopted,
as described in the Acoustic Guidance
methodology. While some of the
relevant data may potentially suggest
changes to TTS/PTS thresholds for some
species, any such changes would not be
expected to change the predicted take
estimates in a manner that would
change the necessary determinations
supporting the issuance of these
regulations, and the data and values
used in this rule reflect the best
available science.
Non-auditory injury (i.e., other than
PTS) and mortality from sonar and other
transducers is so unlikely as to be
discountable under normal conditions
for the reasons explained under the
Potential Effects of Specified Activities
on Marine Mammals and Their Habitat
section—Acoustically-Induced Bubble
Formation Due to Sonars and Other
Pressure-related Impacts and is
therefore not considered further in this
analysis.
Level B Harassment by Behavioral
Disturbance
Though significantly driven by
received level, the onset of Level B
harassment by behavioral disturbance
from anthropogenic noise exposure is
also informed to varying degrees by
other factors related to the source (e.g.,
frequency, predictability, duty cycle),
the environment (e.g., bathymetry), and
the receiving animals (hearing,
motivation, experience, demography,
behavioral context) and can be difficult
to predict (Ellison et al., 2011; Southall
et al., 2007). Based on what the
available science indicates and the
practical need to use thresholds based
on a factor, or factors, that are both
predictable and measurable for most
activities, NMFS uses generalized
acoustic thresholds based primarily on
received level (and distance in some
cases) to estimate the onset of Level B
harassment by behavioral disturbance.
Sonar
As noted above, the Navy coordinated
with NMFS to develop, and propose for
use in this rule, thresholds specific to
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
their military readiness activities
utilizing active sonar that identify at
what received level and distance Level
B harassment by behavioral disturbance
would be expected to result. These
thresholds are referred to as ‘‘behavioral
harassment thresholds’’ throughout the
rest of the rule. These behavioral
harassment thresholds consist of
behavioral response functions (BRFs)
and associated cutoff distances, and are
also referred to, together, as ‘‘the
criteria.’’ These criteria are used to
estimate the number of animals that
may exhibit a behavioral response that
rises to the level of a take when exposed
to sonar and other transducers. The way
the criteria were derived is discussed in
detail in the Criteria and Thresholds for
U.S. Navy Acoustic and Explosive
Effects Analysis (Phase III) report (U.S.
Department of the Navy, 2017c).
Developing these behavioral harassment
criteria involved multiple steps. All
peer-reviewed published behavioral
response studies conducted both in the
field and on captive animals were
examined in order to understand the
breadth of behavioral responses of
marine mammals to tactical sonar and
other transducers. NMFS has carefully
reviewed the Navy’s criteria, i.e., BRFs
and cutoff distances for the species, and
agrees that it is the best available
science and is the appropriate method
to use at this time for determining
impacts to marine mammals from
military sonar and other transducers
and for calculating take and to support
the determinations made in this
proposed rule.
As discussed above, marine mammal
responses to sound (some of which are
considered disturbances that rise to the
level of a take) are highly variable and
context specific, i.e., they are affected by
differences in acoustic conditions;
differences between species and
populations; differences in gender, age,
reproductive status, or social behavior;
and other prior experience of the
individuals. This means that there is
support for considering alternative
approaches for estimating Level B
harassment by behavioral disturbance.
Although the statutory definition of
Level B harassment for military
readiness activities means that a natural
behavior pattern of a marine mammal is
significantly altered or abandoned, the
current state of science for determining
those thresholds is somewhat unsettled.
In its analysis of impacts associated
with sonar acoustic sources (which was
coordinated with NMFS), the Navy used
an updated conservative approach that
likely overestimates the number of takes
by Level B harassment due to behavioral
disturbance and response. Many of the
PO 00000
Frm 00050
Fmt 4701
Sfmt 4702
behavioral responses identified using
the Navy’s quantitative analysis are
most likely to be of moderate severity as
described in the Southall et al. (2007)
behavioral response severity scale.
These ‘‘moderate’’ severity responses
were considered significant if they were
sustained for the duration of the
exposure or longer. Within the Navy’s
quantitative analysis, many reactions
are predicted from exposure to sound
that may exceed an animal’s threshold
for Level B harassment by behavioral
disturbance for only a single exposure (a
few seconds) to several minutes, and it
is likely that some of the resulting
estimated behavioral responses that are
counted as Level B harassment would
not constitute ‘‘significantly altering or
abandoning natural behavioral
patterns.’’ The Navy and NMFS have
used the best available science to
address the challenging differentiation
between significant and non-significant
behavioral reactions (i.e., whether the
behavior has been abandoned or
significantly altered such that it
qualifies as harassment), but have erred
on the cautious side where uncertainty
exists (e.g., counting these lower
duration reactions as take), which likely
results in some degree of overestimation
of Level B harassment by behavioral
disturbance. We consider application of
these behavioral harassment thresholds,
therefore, as identifying the maximum
number of instances in which marine
mammals could be reasonably expected
to experience a disruption in behavior
patterns to a point where they are
abandoned or significantly altered (i.e.,
Level B harassment). Because this is the
most appropriate method for estimating
Level B harassment given the best
available science and uncertainty on the
topic, it is these numbers of Level B
harassment by behavioral disturbance
that are analyzed in the Preliminary
Analysis and Negligible Impact
Determination section and would be
authorized.
In the Navy’s acoustic impact
analyses during Phase II (the previous
phase of Navy testing and training,
2017–2022, see also Navy’s Criteria and
Thresholds for U.S. Navy Acoustic and
Explosive Effects Analysis Technical
Report, 2012), the likelihood of Level B
harassment by behavioral disturbance in
response to sonar and other transducers
was based on a probabilistic function
(termed a BRF), that related the
likelihood (i.e., probability) of a
behavioral response (at the level of a
Level B harassment) to the received
SPL. The BRF was used to estimate the
percentage of an exposed population
that is likely to exhibit Level B
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
harassment due to altered behaviors or
behavioral disturbance at a given
received SPL. This BRF relied on the
assumption that sound poses a
negligible risk to marine mammals if
they are exposed to SPL below a certain
‘‘basement’’ value. Above the basement
exposure SPL, the probability of a
response increased with increasing SPL.
Two BRFs were used in Navy acoustic
impact analyses: BRF1 for mysticetes
and BRF2 for other species. BRFs were
not used for beaked whales during
Phase II analyses. Instead, a step
function at an SPL of 140 dB re: 1 mPa
was used for beaked whales as the
threshold to predict Level B harassment
by behavioral disturbance. Similarly, a
120 dB re: 1 mP step function was used
during Phase II for harbor porpoises.
Developing the behavioral harassment
criteria for Phase III (the current phase
of Navy training and testing activities)
involved multiple steps: all available
behavioral response studies conducted
both in the field and on captive animals
were examined to understand the
breadth of behavioral responses of
marine mammals to sonar and other
transducers (see also Navy’s Criteria and
Thresholds for U.S. Navy Acoustic and
Explosive Effects Analysis (Phase III)
Technical Report, 2017). Six behavioral
response field studies with observations
of 14 different marine mammal species
reactions to sonar or sonar-like signals
and 6 captive animal behavioral studies
with observations of 8 different species
reactions to sonar or sonar-like signals
were used to provide a robust data set
for the derivation of the Navy’s Phase III
marine mammal behavioral response
criteria. The current criteria have been
rigorously vetted within the Navy
community, among scientists during
expert elicitation, and then reviewed by
the public before being applied. All
behavioral response research that has
been published since the derivation of
the Navy’s Phase III criteria (December
2016) has been considered and is
consistent with the current BRFs. While
it is unreasonable to revise and update
the criteria and risk functions every
time a new study is published, these
new studies provide additional
information, and NMFS and the Navy
are considering them for updates to the
criteria in the future, when the next
round of updated criteria will be
developed. The Navy and NMFS
continue to evaluate the information as
new science becomes available.
Marine mammal species were placed
into behavioral criteria groups based on
their known or suspected behavioral
sensitivities to sound. In most cases
these divisions were driven by
taxonomic classifications (e.g.,
mysticetes, pinnipeds). The data from
the behavioral studies were analyzed by
looking for significant responses, or lack
thereof, for each experimental session.
The Navy used cutoff distances
beyond which the potential of
significant behavioral responses (and
therefore Level B harassment) is
considered to be unlikely (see Table 7
below). These distances were
determined by examining all available
published field observations of
behavioral reactions to sonar or sonar-
49705
like signals that included the distance
between the sound source and the
marine mammal. The longest distance,
rounded up to the nearest 5-km
increment, was chosen as the cutoff
distance for each behavioral criteria
group (i.e., odontocetes, pinnipeds,
mysticetes, beaked whales, and harbor
porpoise). For animals within the cutoff
distance, BRFs for each behavioral
criteria group based on a received SPL
as presented in Chapter 6, Section
6.4.2.1 (Methods for Analyzing Impacts
from Sonars and other Transducers) of
the Navy’s rulemaking/LOA application
were used to predict the probability of
a potential significant behavioral
response. For training activities that
contain multiple platforms or tactical
sonar sources that exceed 215 dB re: 1
mPa at 1 m, this cutoff distance is
substantially increased (i.e., doubled)
from values derived from the literature.
The use of multiple platforms and
intense sound sources are factors that
probably increase responsiveness in
marine mammals overall (however, we
note that helicopter dipping sonars were
considered in the intense sound source
group, despite lower source levels,
because of data indicating that marine
mammals are sometimes more
responsive to the less predictable
employment of this source). There are
currently few behavioral observations
under these circumstances; therefore,
the Navy conservatively predicted
significant behavioral responses that
would rise to Level B harassment at
farther ranges than shown in Table 7,
versus less intense events.
TABLE 7—CUTOFF DISTANCES FOR MODERATE SOURCE LEVEL, SINGLE PLATFORM TRAINING EVENTS AND FOR ALL
OTHER EVENTS WITH MULTIPLE PLATFORMS OR SONAR WITH SOURCE LEVELS AT OR EXCEEDING 215 dB re: 1 μPa
at 1 m
Moderate SL/single
platform cutoff distance
(km)
Criteria group
Odontocetes .....................................................................................................................
Pinnipeds .........................................................................................................................
Mysticetes ........................................................................................................................
Beaked Whales ................................................................................................................
Harbor Porpoise ...............................................................................................................
10
5
10
25
20
High SL/multi-platform
cutoff distance
(km)
20
10
20
50
40
lotter on DSK11XQN23PROD with PROPOSALS2
Notes: dB re: 1 μPa at 1 m = decibels referenced to 1 micropascal at 1 meter, km = kilometer, SL = source level.
The range to received sound levels in
6-dB steps from three representative
sonar bins and the percentage of
animals that may be taken by Level B
harassment under each BRF are shown
in Tables 8 through 10. Cells are shaded
if the mean range value for the specified
received level exceeds the distance
cutoff distance for a particular group
and therefore are not included in the
estimated take. See Chapter 6, Section
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
6.4.2.1 (Methods for Analyzing Impacts
from Sonars and Other Transducers) of
the Navy’s rulemaking/LOA application
for further details on the derivation and
use of the BRFs, thresholds, and the
cutoff distances to identify takes by
Level B harassment, which were
coordinated with NMFS. As noted
previously, NMFS carefully reviewed,
and contributed to, the Navy’s proposed
behavioral harassment thresholds (i.e.,
PO 00000
Frm 00051
Fmt 4701
Sfmt 4702
the BRFs and the cutoff distances) for
the species, and agrees that these
methods represent the best available
science at this time for determining
impacts to marine mammals from sonar
and other transducers.
Tables 8 through 10 identify the
maximum likely percentage of exposed
individuals taken at the indicated
received level and associated range (in
which marine mammals would be
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
reasonably expected to experience a
disruption in behavior patterns to a
point where they are abandoned or
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
significantly altered) for mid-frequency
active sonar (MFAS).
BILLING CODE 3510–22–P
PO 00000
Frm 00052
Fmt 4701
Sfmt 4725
E:\FR\FM\11AUP2.SGM
11AUP2
EP11AU22.001</GPH>
49706
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00053
Fmt 4701
Sfmt 4725
E:\FR\FM\11AUP2.SGM
11AUP2
49707
EP11AU22.002</GPH>
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
49708
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
BILLING CODE 3510–22–C
Explosives
Phase III explosive criteria for
behavioral harassment thresholds for
marine mammals is the functional
hearing groups’ TTS onset threshold (in
SEL) minus 5 dB (see Table 11 below
and Table 6 for the TTS thresholds for
explosives) for events that contain
multiple impulses from explosives
underwater. This is the same approach
as taken in Phase II for explosive
analysis. See the Criteria and
Thresholds for U.S. Navy Acoustic and
Explosive Effects Analysis (Phase III)
report (U.S. Department of the Navy,
2017c) for detailed information on how
the criteria and thresholds were derived.
NMFS continues to concur that this
approach represents the best available
science for determining impacts to
marine mammals from explosives. As
noted previously, detonations occurring
in air at a height of 33 ft (10 m) or less
above the water surface, and
detonations occurring directly on the
water surface were modeled to detonate
at a depth of 0.3 ft (0.1 m) below the
water surface. There are no detonations
of explosives occurring underwater as
part of the planned activities.
Medium
Underwater
Underwater
Underwater
Underwater
Underwater
Functional hearing group
.................................................................................
.................................................................................
.................................................................................
.................................................................................
.................................................................................
Low-frequency cetaceans ...........................................................
Mid-frequency cetaceans ...........................................................
High-frequency cetaceans ..........................................................
Phocids .......................................................................................
Otariids .......................................................................................
Note: Weighted SEL thresholds in dB re: 1 μPa2s underwater
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00054
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
SEL
(weighted)
163
165
135
165
183
EP11AU22.003</GPH>
lotter on DSK11XQN23PROD with PROPOSALS2
TABLE 11—THRESHOLDS FOR LEVEL B HARASSMENT BY BEHAVIORAL DISTURBANCE FOR EXPLOSIVES FOR MARINE
MAMMALS
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
Navy’s Acoustic Effects Model
The Navy’s Acoustic Effects Model
calculates sound energy propagation
from sonar and other transducers and
explosives during naval activities and
the sound received by animat
dosimeters. Animat dosimeters are
virtual representations of marine
mammals distributed in the area around
the modeled naval activity and each
dosimeter records its individual sound
‘‘dose.’’ The model bases the
distribution of animats over the TMAA,
the portion of the GOA Study Area
where sonar and other transducers and
explosives are proposed for use, on the
density values in the Navy Marine
Species Density Database and
distributes animats in the water column
proportional to the known time that
species spend at varying depths.
The model accounts for
environmental variability of sound
propagation in both distance and depth
when computing the sound level
received by the animats. The model
conducts a statistical analysis based on
multiple model runs to compute the
estimated effects on animals. The
number of animats that exceed the
thresholds for effects is tallied to
provide an estimate of the number of
marine mammals that could be affected.
Assumptions in the Navy model
intentionally err on the side of
overestimation when there are
unknowns. Naval activities are modeled
as though they would occur regardless
of proximity to marine mammals,
meaning that no mitigation is
considered (i.e., no power down or shut
down modeled) and without any
avoidance of the activity by the animal.
The final step of the quantitative
analysis of acoustic effects is to consider
the implementation of mitigation and
the possibility that marine mammals
would avoid continued or repeated
sound exposures. For more information
on this process, see the discussion in
the Take Request subsection below. All
explosives used in the TMAA would
detonate in the air at or above the water
surface. However, for this analysis,
detonations occurring in air at a height
of 33 ft. (10 m) or less above the water
surface, and detonations occurring
directly on the water surface were
modeled to detonate at a depth of 0.3 ft.
(0.1 m) below the water surface since
there is currently no other identified
methodology for modeling potential
effects to marine mammals that are
underwater as a result of detonations
occurring at or above the surface of the
ocean. This overestimates the amount of
explosive and acoustic energy entering
the water.
The model estimates the impacts
caused by individual training exercises.
During any individual modeled event,
impacts to individual animats are
considered over 24-hour periods. The
animats do not represent actual animals,
but rather they represent a distribution
of animals based on density and
abundance data, which allows for a
statistical analysis of the number of
instances that marine mammals may be
exposed to sound levels resulting in an
effect. Therefore, the model estimates
the number of instances in which an
effect threshold was exceeded over the
course of a year, but does not estimate
the number of individual marine
mammals that may be impacted over a
year (i.e., some marine mammals could
be impacted several times, while others
would not experience any impact). A
detailed explanation of the Navy’s
Acoustic Effects Model is provided in
the technical report Quantifying
Acoustic Impacts on Marine Mammals
and Sea Turtles: Methods and
Analytical Approach for Phase III
Training and Testing (U.S. Department
of the Navy, 2018).
Range to Effects
This section provides range to effects
for sonar and other active acoustic
sources as well as explosives to specific
acoustic thresholds determined using
49709
the Navy Acoustic Effects Model.
Marine mammals exposed within these
ranges for the shown duration are
predicted to experience the associated
effect. Range to effects is important
information in not only predicting
acoustic impacts, but also in verifying
the accuracy of model results against
real-world situations and determining
adequate mitigation ranges to avoid
higher level effects, especially
physiological effects to marine
mammals.
Sonar
The ranges to received sound levels in
6-dB steps from three representative
sonar bins and the percentage of the
total number of animals that may be
disturbed (and therefore Level B
harassment) under each BRF are shown
in Table 8 though Table 10 above. See
Chapter 6, Section 6.4.2.1 (Methods for
Analyzing Impacts from Sonars and
Other Transducers) of the Navy’s
rulemaking/LOA application for
additional details on the derivation and
use of the BRFs, thresholds, and the
cutoff distances that are used to identify
Level B harassment by behavioral
disturbance. NMFS has reviewed the
range distance to effect data provided by
the Navy and concurs with the analysis.
The ranges to PTS for three
representative sonar systems for an
exposure of 30 seconds is shown in
Table 12 relative to the marine
mammal’s functional hearing group.
This period (30 seconds) was chosen
based on examining the maximum
amount of time a marine mammal
would realistically be exposed to levels
that could cause the onset of PTS based
on platform (e.g., ship) speed and a
nominal animal swim speed of
approximately 1.5 m per second. The
ranges provided in the table include the
average range to PTS, as well as the
range from the minimum to the
maximum distance at which PTS is
possible for each hearing group.
TABLE 12—RANGES TO PERMANENT THRESHOLD SHIFT (METERS) FOR THREE REPRESENTATIVE SONAR SYSTEMS
Approximate range in meters for PTS from 30 second exposure 1
Hearing group
lotter on DSK11XQN23PROD with PROPOSALS2
Sonar bin MF1
High-frequency cetaceans ...........................................................
Low-frequency cetaceans ............................................................
Mid-frequency cetaceans .............................................................
Otariids 2 ......................................................................................
Phocids 2 ......................................................................................
Sonar bin MF4
180 (180–180)
65 (65–65)
16 (16–16)
6 (6–6)
45 (45–45)
31 (30–35)
13 (0–15)
3 (3–3)
0 (0–0)
11 (11–11)
Sonar bin MF5
9 (8–10)
0 (0–0)
0 (0–0)
0 (0–0)
0 (0–0)
1 PTS ranges extend from the sonar or other transducer sound source to the indicated distance. The average range to PTS is provided as well
as the range from the estimated minimum to the maximum range to PTS in parenthesis.
2 Otariids and phocids are separated because true seals (phocids) generally dive much deeper than sea lions and fur seals (otariids).
Notes: MF = mid-frequency, PTS = permanent threshold shift.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00055
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
49710
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
The tables below illustrate the range
to TTS for 1, 30, 60, and 120 seconds
from three representative sonar systems
(see Table 13 through Table 15).
TABLE 13—RANGES TO TEMPORARY THRESHOLD SHIFT (METERS) FOR SONAR BIN MF1 OVER A REPRESENTATIVE
RANGE OF ENVIRONMENTS WITHIN THE TMAA
Approximate TTS ranges (meters) 1
Hearing group
Sonar bin MF1
1 second
High-frequency cetaceans ...............
Low-frequency cetaceans ................
Mid-frequency cetaceans .................
Otariids .............................................
Phocids ............................................
3,554 (1,525–6,775)
920 (850–1,025)
209 (200–210)
65 (65–65)
673 (650–725)
30 seconds
60 seconds
3,554 (1,525–6,775)
920 (850–1,025)
209 (200–210)
65 (65–65)
673 (650–725)
5,325 (2,275–9,525)
1,415 (1,025–2,025)
301 (300–310)
100 (100–110)
988 (900–1,025)
120 seconds
7,066 (2,525–13,025)
2,394 (1,275–4,025)
376 (370–390)
132 (130–140)
1,206 (1,025–1,525)
1 Ranges to TTS represent the model predictions in different areas and seasons within the TMAA. The zone in which animals are expected to
incur TTS extends from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum range to TTS in parenthesis.
Notes: MF = mid-frequency, TTS = temporary threshold shift.
TABLE 14—RANGES TO TEMPORARY THRESHOLD SHIFT (METERS) FOR SONAR BIN MF4 OVER A REPRESENTATIVE
RANGE OF ENVIRONMENTS WITHIN THE TMAA
Approximate TTS ranges (meters) 1
Hearing group
Sonar bin MF4
1 second
High-frequency cetaceans ...............
Low-frequency cetaceans ................
Mid-frequency cetaceans .................
Otariids .............................................
Phocids ............................................
30 seconds
318 (220–550)
77 (0–100)
22 (22–22)
8 (8–8)
67 (65–70)
60 seconds
686 (430–1,275)
175 (130–340)
35 (35–35)
15 (15–15)
123 (110–150)
867 (575–1,525)
299 (190–550)
50 (50–50)
19 (19–19)
172 (150–210)
120 seconds
1,225 (825–2,025)
497 (280–1,000)
71 (70–75)
25 (25–25)
357 (240–675)
1 Ranges to TTS represent the model predictions in different areas and seasons within the TMAA. The zone in which animals are expected to
incur TTS extends from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum range to TTS in parenthesis.
Notes: MF = mid-frequency, TTS = temporary threshold shift.
TABLE 15—RANGES TO TEMPORARY THRESHOLD SHIFT (METERS) FOR SONAR BIN MF5 OVER A REPRESENTATIVE
RANGE OF ENVIRONMENTS WITHIN THE TMAA
Approximate TTS ranges (meters) 1
Hearing group
Sonar bin MF5
1 second
High-frequency cetaceans ...............
Low-frequency cetaceans ................
Mid-frequency cetaceans .................
Otariids .............................................
Phocids ............................................
30 seconds
117 (110–140)
9 (0–12)
5 (0–9)
0 (0–0)
9 (8–10)
60 seconds
117 (110–140)
9 (0–12)
5 (0–9)
0 (0–0)
9 (8–10)
176 (150–320)
13 (0–17)
12 (11–13)
0 (0–0)
14 (14–15)
120 seconds
306 (210–800)
19 (0–24)
18 (17–18)
0 (0–0)
21 (21–22)
1 Ranges to TTS represent the model predictions in different areas and seasons within the TMAA. The zone in which animals are expected to
incur TTS extends from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum range to TTS in parenthesis.
Notes: MF = mid-frequency, TTS = temporary threshold shift.
lotter on DSK11XQN23PROD with PROPOSALS2
Explosives
The following section provides the
range (distance) over which specific
physiological or behavioral effects are
expected to occur based on the
explosive criteria (see Chapter 6,
Section 6.5.2 (Impacts from Explosives)
of the Navy’s rulemaking/LOA
application and the Criteria and
Thresholds for U.S. Navy Acoustic and
Explosive Effects Analysis (Phase III)
report (U.S. Department of the Navy,
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
2017c)) and the explosive propagation
calculations from the Navy Acoustic
Effects Model (see Chapter 6, Section
6.5.2.2 (Impact Ranges for Explosives) of
the Navy’s rulemaking/LOA
application). The range to effects are
shown for a range of explosive bins,
from E5 (greater than 5–10 lbs net
explosive weight) to E12 (greater than
650 lbs to 1,000 lbs net explosive
weight) (Tables 16 through 29). Ranges
are determined by modeling the
PO 00000
Frm 00056
Fmt 4701
Sfmt 4702
distance that noise from an explosion
would need to propagate to reach
exposure level thresholds specific to a
hearing group that would cause
behavioral response (to the degree of
Level B harassment), TTS, PTS, and
non-auditory injury. NMFS has
reviewed the range distance to effect
data provided by the Navy and concurs
with the analysis. Range to effects is
important information in not only
predicting impacts from explosives, but
E:\FR\FM\11AUP2.SGM
11AUP2
49711
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
also in verifying the accuracy of model
results against real-world situations and
determining adequate mitigation ranges
to avoid higher level effects, especially
physiological effects to marine
mammals. For additional information
on how ranges to impacts from
explosions were estimated, see the
technical report Quantifying Acoustic
Impacts on Marine Mammals and Sea
Turtles: Methods and Analytical
Approach for Phase III Training and
Testing (U.S. Navy, 2018).
Tables 16 through 27 show the
minimum, average, and maximum
ranges to onset of auditory and likely
behavioral effects that rise to the level
of Level B harassment based on the
developed thresholds. Ranges are
provided for a representative source
depth and cluster size (the number of
rounds fired, or buoys dropped, within
a very short duration) for each bin. For
events with multiple explosions, sound
from successive explosions can be
expected to accumulate and increase the
range to the onset of an impact based on
SEL thresholds. Ranges to non-auditory
injury and mortality are shown in Table
28 and Table 29, respectively.
No underwater detonations are
planned as part of the Navy’s activities,
but marine mammals could be exposed
to in-air detonations at or above the
water surface. The Navy Acoustic
Effects Model cannot account for the
highly non-linear effects of cavitation
and surface blow off for shallow
underwater explosions, nor can it
estimate the explosive energy entering
the water from a low-altitude
detonation. Thus, for this analysis,
sources detonating in-air at or above
(within 10 m above) the water surface
are modeled as if detonating completely
underwater at a depth of 0.1 m, with all
energy reflected into the water rather
than released into the air. Therefore, the
amount of explosive and acoustic
energy entering the water, and
consequently the estimated ranges to
effects, are likely to be overestimated.
Table 16 shows the minimum,
average, and maximum ranges to onset
of auditory and likely behavioral effects
that rise to the level of Level B
harassment for high-frequency cetaceans
based on the developed thresholds.
TABLE 16—SEL-BASED RANGES TO ONSET PTS, ONSET TTS, AND BEHAVIORAL DISTURBANCE (IN METERS) FOR HIGHFREQUENCY CETACEANS
Range to effects for explosives: high-frequency cetaceans 1
Source depth
(m)
Bin2
E5 .........................................
0.1
E9 .........................................
E10 .......................................
E12 .......................................
0.1
0.1
0.1
Cluster size
PTS
1
7
1
1
1
TTS
910 (850–975)
1,275 (1,025–1,525)
1,348 (1,025–1,775)
1,546 (1,025–2,025)
1,713 (1,275–2,025)
1,761
3,095
3,615
4,352
5,115
(1,275–2,275)
(2,025–4,525)
(2,025–5,775)
(2,275–7,275)
(2,275–7,775)
Behavioral
2,449 (1,775–3,275)
4,664 (2,275–7,775)
5,365 (2,525–8,525)
5,949 (2,525–9,275)
6,831 (2,775–10,275)
1 Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in
parentheses. Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
ranges to effect. PTS = permanent threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
2 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
Table 17 shows the minimum,
average, and maximum ranges to onset
of auditory effects for high-frequency
cetaceans based on the developed
thresholds.
TABLE 17—PEAK PRESSURE-BASED RANGES TO ONSET PTS AND ONSET TTS (IN METERS) FOR HIGH FREQUENCY
CETACEANS
Range to effects for explosives: high-frequency cetaceans1
Source depth
(m)
Bin 2
E5 .....................................................................................
0.1
E9 .....................................................................................
E10 ...................................................................................
E12 ...................................................................................
0.1
0.1
0.1
Cluster size
PTS
1
7
1
1
1
1,161
1,161
2,331
2,994
4,327
(1,000–1,525)
(1,000–1,525)
(1,525–2,775)
(1,775–4,525)
(2,025–7,275)
TTS
1,789 (1,025–2,275)
1,789 (1,025–2,275)
5,053 (2,025–9,275)
7,227 (2,025–14,775)
10,060 (2,025–22,275)
lotter on DSK11XQN23PROD with PROPOSALS2
1 Average distance (meters) is shown with the minimum and maximum distances due to varying propagation environments in parentheses. No
underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface
is released underwater, likely over-estimating ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
2 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
Table 18 shows the minimum,
average, and maximum ranges to onset
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
of auditory and likely behavioral effects
that rise to the level of Level B
PO 00000
Frm 00057
Fmt 4701
Sfmt 4702
harassment for low-frequency cetaceans
based on the developed thresholds.
E:\FR\FM\11AUP2.SGM
11AUP2
49712
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
TABLE 18—SEL-BASED RANGES TO ONSET PTS, ONSET TTS, AND BEHAVIORAL DISTURBANCE (IN METERS) FOR LOWFREQUENCY CETACEANS
Range to effects for explosives: low-frequency cetaceans 1
Source depth
(m)
Bin 2
E5 .............................................
0.1
E9 .............................................
E10 ...........................................
E12 ...........................................
0.1
0.1
0.1
Cluster size
PTS
1
7
1
1
1
171
382
453
554
643
TTS
(100–190)
(170–450)
(180–550)
(210–700)
(230–825)
633 (230–825)
1,552 (380–5,775)
3,119 (550–9,025)
4,213 (600–13,025)
6,402 (1,275–19,775)
Behavioral
934 (310–1,525)
3,712 (600–13,025)
6,462 (1,275–19,275)
9,472 (1,775–27,275)
13,562 (2,025–34,775)
1 Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in
parentheses. Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
ranges to effect. PTS = permanent threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
2 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
Table 19 shows the minimum,
average, and maximum ranges to onset
of auditory effects for low-frequency
cetaceans based on the developed
thresholds.
TABLE 19—PEAK PRESSURE-BASED RANGES TO ONSET PTS AND ONSET TTS (IN METERS) FOR LOW FREQUENCY
CETACEANS
Range to effects for explosives: low-frequency cetaceans 1
Source depth
(m)
Bin 2
E5 .....................................................................................
0.1
E9 .....................................................................................
E10 ...................................................................................
E12 ...................................................................................
0.1
0.1
0.1
Cluster size
PTS
1
7
1
1
1
419 (170–500)
419 (170–500)
855 (270–1,275)
953 (300–1,525)
1,135 (360–1,525)
TTS
690 (210–875)
690 (210–875)
1,269 (400–1,775)
1,500 (450–2,525)
1,928 (525–4,775)
1 Average distance (meters) is shown with the minimum and maximum distances due to varying propagation environments in parentheses. No
underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface
is released underwater, likely over-estimating ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
2 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
Table 20 shows the minimum,
average, and maximum ranges to onset
of auditory and likely behavioral effects
that rise to the level of Level B
harassment for mid-frequency cetaceans
based on the developed thresholds.
TABLE 20—SEL-BASED RANGES TO ONSET PTS, ONSET TTS, AND BEHAVIORAL DISTURBANCE (IN METERS) FOR MIDFREQUENCY CETACEANS
Range to effects for explosives: mid-frequency cetaceans 1
Bin 2
Source depth
(m)
E5 .........................................
0.1
E9 .........................................
E10 .......................................
E12 .......................................
0.1
0.1
0.1
Cluster size
PTS
1
7
1
1
1
TTS
79 (75–80)
185 (180–190)
215 (210–220)
275 (270–280)
340 (340–340)
363 (360–370)
777 (650–825)
890 (700–950)
974 (750–1,025)
1,164 (825–1,275)
Behavioral
581 (550–600)
1,157 (800–1,275)
1,190 (825–1,525)
1,455 (875–1,775)
1,746 (925–2,025)
lotter on DSK11XQN23PROD with PROPOSALS2
1 Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in
parentheses. Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
ranges to effect. PTS = permanent threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
2 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
Table 21 shows the minimum,
average, and maximum ranges to onset
of auditory effects for mid-frequency
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
cetaceans based on the developed
thresholds.
PO 00000
Frm 00058
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
49713
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
TABLE 21—PEAK PRESSURE-BASED RANGES TO ONSET PTS AND ONSET TTS (IN METERS) FOR MID-FREQUENCY
CETACEANS
Range to effects for explosives: mid-frequency cetaceans1
Source depth
(m)
Bin 2
E5 .....................................................................................
0.1
E9 .....................................................................................
E10 ...................................................................................
E12 ...................................................................................
0.1
0.1
0.1
Cluster size
PTS
1
7
1
1
1
158
158
463
558
679
TTS
(150–160)
(150–160)
(430–470)
(490–575)
(550–725)
295 (290–300)
295 (290–300)
771 (575–850)
919 (625–1,025)
1,110 (675–1,275)
1 Average distance (meters) is shown with the minimum and maximum distances due to varying propagation environments in parentheses. No
underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface
is released underwater, likely over-estimating ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
2 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
Table 22 shows the minimum,
average, and maximum ranges to onset
of auditory and likely behavioral effects
that rise to the level of Level B
harassment for otariid pinnipeds based
on the developed thresholds.
TABLE 22—SEL-BASED RANGES TO ONSET PTS, ONSET TTS, AND BEHAVIORAL DISTURBANCE (IN METERS) FOR
OTARIIDS
Range to effects for explosives: otariids 1
Source depth
(m)
Bin 2
E5 .........................................
0.1
E9 .........................................
E10 .......................................
E12 .......................................
0.1
0.1
0.1
Cluster size
1
7
1
1
1
PTS
TTS
25 (24–25)
58 (55–60)
68 (65–70)
88 (85–90)
105 (100–110)
110
265
320
400
490
Behavioral
(110–110)
(260–270)
(310–330)
(390–410)
(470–500)
185
443
512
619
733
(180–190)
(430–450)
(490–525)
(575–675)
(650–825)
1 Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in
parentheses. Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
ranges to effect. PTS = permanent threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
2 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
Table 23 shows the minimum,
average, and maximum ranges to onset
of auditory effects for otariid pinnipeds
based on the developed thresholds.
TABLE 23—PEAK PRESSURE-BASED RANGES TO ONSET PTS AND ONSET TTS (IN METERS) FOR OTARIIDS
Range to effects for explosives: otariids 1
Source
depth (m)
Bin 2
E5 .............................................................................................
0.1
E9 .............................................................................................
E10 ...........................................................................................
E12 ...........................................................................................
0.1
0.1
0.1
Cluster Size
PTS
1
7
1
1
1
128
128
383
478
583
(120–130)
(120–130)
(380–390)
(470–480)
(550–600)
TTS
243 (240–250)
243 (240–250)
656 (600–700)
775 (675–850)
896 (750–1,025)
lotter on DSK11XQN23PROD with PROPOSALS2
1 Average distance (meters) is shown with the minimum and maximum distances due to varying propagation environments in parentheses. No
underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface
is released underwater, likely over-estimating ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
2 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
Table 24 shows the minimum,
average, and maximum ranges to onset
of auditory and likely behavioral effects
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
that rise to the level of Level B
harassment for phocid pinnipeds,
PO 00000
Frm 00059
Fmt 4701
Sfmt 4702
excluding elephant seals, based on the
developed thresholds.
E:\FR\FM\11AUP2.SGM
11AUP2
49714
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
TABLE 24—SEL-BASED RANGES TO ONSET PTS, ONSET TTS, AND BEHAVIORAL DISTURBANCE (IN METERS) FOR
PHOCIDS, EXCLUDING ELEPHANT SEALS
Range to effects for explosives: phocids 1
Source depth
(m)
Bin 2
E5 .............................................
Cluster size
0.1
E9 .............................................
E10 ...........................................
E12 ...........................................
PTS
1
7
1
1
1
0.1
0.1
0.1
150
360
425
525
653
TTS
(150–150)
(350–370)
(420–430)
(525–525)
(650–675)
1,306
1,369
1,716
1,935
681 (675–700)
(1,025–1,525)
(1,025–1,525)
(1,275–2,275)
(1,275–2,775)
Behavioral
1,009 (975–1,025)
1,779 (1,275–2,275)
2,084 (1,525–2,775)
2,723 (1,525–4,025)
3,379 (1,775–5,775)
1 Excluding
elephant seals.
distance (meters) is shown with the minimum and maximum distances due to varying propagation environments in parentheses. No
underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface
is released underwater, likely over-estimating ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
3 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
2 Average
Table 25 shows the minimum,
average, and maximum ranges to onset
of auditory effects for phocids
pinnipeds, excluding elephant seals,
based on the developed thresholds.
TABLE 25—PEAK PRESSURE-BASED RANGES TO ONSET PTS AND ONSET TTS (IN METERS) FOR PHOCIDS, EXCLUDING
ELEPHANT SEALS
Range to effects for explosives: phocids 1
Source depth
(m)
Bin 2
E5 .....................................................................................
0.1
E9 .....................................................................................
E10 ...................................................................................
E12 ...................................................................................
0.1
0.1
0.1
Cluster size
PTS
1
7
1
1
1
537 (525–550)
537 (525–550)
1,150 (1,025–1,275)
1,400 (1,025–1,775)
1,713 (1,275–2,025)
TTS
931 (875–975)
931 (875–975)
1,845 (1,275–2,525)
2,067 (1,275–2,525)
2,306 (1,525–2,775)
1 Excluding
elephant seals.
distance (meters) is shown with the minimum and maximum distances due to varying propagation environments in parentheses. No
underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface
is released underwater, likely over-estimating ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
3 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
2 Average
Table 26 shows the minimum,
average, and maximum ranges to onset
of auditory and likely behavioral effects
that rise to the level of Level B
harassment for elephant seals based on
the developed thresholds.
TABLE 26—SEL-BASED RANGES TO ONSET PTS, ONSET TTS, AND BEHAVIORAL DISTURBANCE (IN METERS) FOR
ELEPHANT SEALS 1
Range to effects for explosives: phocids (elephant seals) 2
Bin 3
Source depth
(m)
E5 .............................................
Cluster size
0.1
E9 .............................................
E10 ...........................................
E12 ...........................................
PTS
1
7
1
1
1
0.1
0.1
0.1
150
360
425
525
656
TTS
(150–150)
(350–370)
(420–430)
(525–525)
(650–675)
1,525
1,775
2,150
2,609
688 (675–700)
(1,525–1,525)
(1,775–1,775)
(2,025–2,525)
(2,525–3,025)
1 Elephant
Behavioral
1,025
2,345
2,858
3,421
4,178
(1,025–1,025)
(2,275–2,525)
(2,775–3,275)
(3,025–4,025)
(3,525–5,775)
seals are separated from other phocids due to their dive behavior, which far exceeds the dive depths of the other phocids analyzed.
distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in
parentheses. Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
ranges to effect. PTS = permanent threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
3 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
lotter on DSK11XQN23PROD with PROPOSALS2
2 Average
Table 27 shows the minimum,
average, and maximum ranges to onset
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
of auditory effects for elephant seals,
based on the developed thresholds.
PO 00000
Frm 00060
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
49715
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
TABLE 27—PEAK PRESSURE-BASED RANGES TO ONSET PTS AND ONSET TTS (IN METERS) FOR ELEPHANT SEALS 1
Range to effects for explosives: phocids (elephant seals) 2
Source depth
(m)
Bin 3
E5 .....................................................................................
0.1
E9 .....................................................................................
E10 ...................................................................................
E12 ...................................................................................
0.1
0.1
0.1
Cluster size
PTS
1
7
1
1
1
TTS
537 (525–550)
537 (525–550)
1,275 (1,275–1,275)
1,775 (1,775–1,775)
2,025 (2,025–2,025)
963 (950–975)
963 (950–975)
2,525 (2,525–2,525)
3,046 (3,025–3,275)
3,539 (3,525–3,775)
1 Elephant
seals are separated from other phocids due to their dive behavior, which far exceeds the dive depths of the other phocids analyzed.
distance (meters) is shown with the minimum and maximum distances due to varying propagation environments in parentheses. No
underwater explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface
is released underwater, likely over-estimating ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
3 Bin (net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
2 Average
Table 28 shows the minimum,
average, and maximum ranges due to
varying propagation conditions to nonauditory injury as a function of animal
mass and explosive bin (i.e., net
explosive weight). Ranges to
gastrointestinal tract injury typically
exceed ranges to slight lung injury;
therefore, the maximum range to effect
is not mass-dependent. Animals within
these water volumes would be expected
to receive minor injuries at the outer
ranges, increasing to more substantial
injuries, and finally mortality as an
animal approaches the detonation point.
TABLE 28—RANGES TO 50 PERCENT
NON-AUDITORY INJURY FOR ALL MARINE MAMMAL HEARING GROUPS
Range to non-auditory
injury (meters) 2
Bin 1
E5 .............................
E9 .............................
E10 ...........................
E12 ...........................
40 (40–40)
121 (90–130)
152 (100–160)
190 (110–200)
2 Average distance (m) is shown with the
minimum and maximum distances due to varying propagation environments in parentheses.
Notes: All ranges to non-auditory injury
within this table are driven by gastrointestinal
tract injury thresholds regardless of animal
mass.
Ranges to mortality, based on animal
mass, are shown in Table 29 below.
1 Bin (net explosive weight, lb.): E5 (>5–10),
E9 (>100–250), E10 (>250–500), E12 (>650–
1,000).
TABLE 29—RANGES TO 50 PERCENT MORTALITY RISK FOR ALL MARINE MAMMAL HEARING GROUPS AS A FUNCTION OF
ANIMAL MASS
Animal mass intervals (kg) 2
Bin 1
10
E5 .........................
E9 .........................
E10 .......................
E12 .......................
13
35
43
55
250
(12–14)
(30–40)
(40–50)
(50–60)
1,000
7 (4–11)
20 (13–30)
25 (16–40)
30 (20–50)
3 (3–4)
10 (9–13)
13 (11–16)
17 (14–20)
5,000
25,000
2 (1–3)
7 (6–9)
9 (7–11)
11 (9–14)
1
4
5
6
72,000
(1–1)
(3–4)
(4–5)
(5–7)
1
3
4
5
(0–1)
(2–3)
(3–4)
(4–6)
1 Bin
(net explosive weight, lb.): E5 (>5–10), E9 (>100–250), E10 (>250–500), E12 (>650–1,000).
distance (m) to mortality is depicted above the minimum and maximum distances, which are in parentheses for each animal mass
interval.
2 Average
lotter on DSK11XQN23PROD with PROPOSALS2
Marine Mammal Density
A quantitative analysis of impacts on
a species or stock requires data on their
abundance and distribution that may be
affected by anthropogenic activities in
the potentially impacted area. The most
appropriate metric for this type of
analysis is density, which is the number
of animals present per unit area. Marine
species density estimation requires a
significant amount of effort to both
collect and analyze data to produce a
reasonable estimate. Unlike surveys for
terrestrial wildlife, many marine species
spend much of their time submerged,
and are not easily observed. In order to
collect enough sighting data to make
reasonable density estimates, multiple
observations are required, often in areas
that are not easily accessible (e.g., far
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
offshore). Ideally, marine mammal
species sighting data would be collected
for the specific area and time period
(e.g., season) of interest and density
estimates derived accordingly. However,
in many places, poor weather
conditions and high sea states prohibit
the completion of comprehensive visual
surveys.
For most cetacean species, abundance
is estimated using line-transect surveys
or mark-recapture studies (e.g., Barlow,
2010; Barlow and Forney, 2007;
Calambokidis et al., 2008). The result
provides one single density estimate
value for each species across broad
geographic areas. This is the general
approach applied in estimating cetacean
abundance in NMFS’ Stock Assessment
Reports (SARs). Although the single
PO 00000
Frm 00061
Fmt 4701
Sfmt 4702
value provides a good average estimate
of abundance (total number of
individuals) for a specified area, it does
not provide information on the species
distribution or concentrations within
that area, and it does not estimate
density for other timeframes or seasons
that were not surveyed. More recently,
spatial habitat modeling developed by
NMFS’ Southwest Fisheries Science
Center has been used to estimate
cetacean densities (Barlow et al., 2009;
Becker et al., 2010, 2012a, 2012b, 2012c,
2014, 2016; Ferguson et al., 2006a;
Forney et al., 2012, 2015; Redfern et al.,
2006). These models estimate cetacean
density as a continuous function of
habitat variables (e.g., sea surface
temperature, seafloor depth, etc.) and
thus allow predictions of cetacean
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49716
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
densities on finer spatial scales than
traditional line-transect or mark
recapture analyses and for areas that
have not been surveyed. Within the
geographic area that was modeled,
densities can be predicted wherever
these habitat variables can be measured
or estimated.
Ideally, density data would be
available for all species throughout the
study area year-round, in order to best
estimate the impacts of Navy activities
on marine species. However, in many
places ship availability, lack of funding,
inclement weather conditions, and high
sea states prevent the completion of
comprehensive year-round surveys.
Even with surveys that are completed,
poor conditions may result in lower
sighting rates for species that would
typically be sighted with greater
frequency under favorable conditions.
Lower sighting rates preclude having an
acceptably low uncertainty in the
density estimates. A high level of
uncertainty, indicating a low level of
confidence in the density estimate, is
typical for species that are rare or
difficult to sight. In areas where survey
data are limited or non-existent, known
or inferred associations between marine
habitat features and the likely presence
of specific species are sometimes used
to predict densities in the absence of
actual animal sightings. Consequently,
there is no single source of density data
for every area, species, and season
because of the fiscal costs, resources,
and effort involved in providing enough
survey coverage to sufficiently estimate
density.
To characterize marine species
density for large oceanic regions, the
Navy reviews, critically assesses, and
prioritizes existing density estimates
from multiple sources, requiring the
development of a systematic method for
selecting the most appropriate density
estimate for each combination of
species/stock, area, and season. The
selection and compilation of the best
available marine species density data
resulted in the Navy Marine Species
Density Database (NMSDD), which
includes seasonal density values for
every marine mammal species and stock
present within the TMAA. This
database is described in the technical
report titled U.S. Navy Marine Species
Density Database Phase III for the Gulf
of Alaska Temporary Maritime
Activities Area (U.S. Department of the
Navy, 2021), hereafter referred to as the
Density Technical Report. NMFS vetted
all cetacean densities by the Navy prior
to use in the Navy’s acoustic analysis for
the current rulemaking process.
A variety of density data and density
models are needed in order to develop
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
a density database that encompasses the
entirety of the TMAA (densities beyond
the TMAA were not considered because
sonar and other transducers and
explosives would not be used in the
GOA Study Area beyond the TMAA).
Because this data is collected using
different methods with varying amounts
of accuracy and uncertainty, the Navy
has developed a hierarchy to ensure the
most accurate data is used when
available. The Density Technical Report
describes these models in detail and
provides detailed explanations of the
models applied to each species density
estimate. The below list describes
models in order of preference.
1. Spatial density models are
preferred and used when available
because they provide an estimate with
the least amount of uncertainty by
deriving estimates for divided segments
of the sampling area. These models (see
Becker et al., 2016; Forney et al., 2015)
predict spatial variability of animal
presence as a function of habitat
variables (e.g., sea surface temperature,
seafloor depth, etc.). This model is
developed for areas, species, and, when
available, specific timeframes (months
or seasons) with sufficient survey data;
therefore, this model cannot be used for
species with low numbers of sightings.
2. Stratified design-based density
estimates use line-transect survey data
with the sampling area divided
(stratified) into sub-regions, and a
density is predicted for each sub-region
(see Barlow, 2016; Becker et al., 2016;
Bradford et al., 2017; Campbell et al.,
2014; Jefferson et al., 2014). While
geographically stratified density
estimates provide a better indication of
a species’ distribution within the study
area, the uncertainty is typically high
because each sub-region estimate is
based on a smaller stratified segment of
the overall survey effort.
3. Design-based density estimations
use line-transect survey data from vessel
and aerial surveys designed to cover a
specific geographic area (see Carretta et
al., 2015). These estimates use the same
survey data as stratified design-based
estimates, but are not segmented into
sub-regions and instead provide one
estimate for a large surveyed area.
Relative environmental suitability
(RES) models provide estimates for
areas of the oceans that have not been
surveyed using information on species
occurrence and inferred habitat
associations and have been used in past
density databases, however, these
models were not used in the current
quantitative analysis.
The Navy describes some of the
challenges of interpreting the results of
the quantitative analysis summarized
PO 00000
Frm 00062
Fmt 4701
Sfmt 4702
above and described in the Density
Technical Report: ‘‘It is important to
consider that even the best estimate of
marine species density is really a model
representation of the values of
concentration where these animals
might occur. Each model is limited to
the variables and assumptions
considered by the original data source
provider. No mathematical model
representation of any biological
population is perfect, and with regards
to marine mammal biodiversity, any
single model method will not
completely explain the actual
distribution and abundance of marine
mammal species. It is expected that
there would be anomalies in the results
that need to be evaluated, with
independent information for each case,
to support if we might accept or reject
a model or portions of the model’’ (U.S.
Department of the Navy, 2017a).
The Navy’s estimate of abundance
(based on the density estimates used) in
the TMAA may differ from population
abundances estimated in NMFS’ SARs
in some cases for a variety of reasons.
Models may predict different
population abundances for many
reasons. The models may be based on
different data sets or different temporal
predictions may be made. The SARs are
often based on single years of NMFS
surveys, whereas the models used by
the Navy generally include multiple
years of survey data from NMFS, the
Navy, and other sources. To present a
single, best estimate, the SARs often use
a single season survey where they have
the best spatial coverage (generally
summer). Navy models often use
predictions for multiple seasons, where
appropriate for the species, even when
survey coverage in non-summer seasons
is limited, to characterize impacts over
multiple seasons as Navy activities may
occur outside of the summer months.
Predictions may be made for different
spatial extents. Many different, but
equally valid, habitat and density
modeling techniques exist and these can
also be the cause of differences in
population predictions. Differences in
population estimates may be caused by
a combination of these factors. Even
similar estimates should be interpreted
with caution and differences in models
fully understood before drawing
conclusions.
In particular, the global population
structure of humpback whales, with 14
DPSs all associated with multiple
feeding areas at which individuals from
multiple DPSs convene, is another
reason that SAR abundance estimates
can differ from other estimates and be
somewhat confusing—the same
individuals are addressed in multiple
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
SARs. For some species, the stock
assessment for a given species may
exceed the Navy’s density prediction
because those species’ home range
extends beyond the GOA Study Area or
TMAA boundaries. The primary source
of density estimates are geographically
specific survey data and either peerreviewed line-transect estimates or
habitat-based density models that have
been extensively validated to provide
the most accurate estimates possible.
These factors and others described in
the Density Technical Report should be
considered when examining the
estimated impact numbers in
comparison to current population
abundance information for any given
species or stock. For a detailed
description of the density and
assumptions made for each species, see
the Density Technical Report.
NMFS coordinated with the Navy in
the development of its take estimates
and concurs that the Navy’s approach
for density appropriately utilizes the
best available science. Later, in the
Preliminary Analysis and Negligible
Impact Determination section, we assess
how the estimated take numbers
compare to stock abundance in order to
better understand the potential number
of individuals impacted, and the
rationale for which abundance estimate
is used is included there.
Take Request
The 2020 GOA DSEIS/OEIS
considered all training activities
proposed to occur in the TMAA, and the
2022 Supplement to the 2020 GOA
DSEIS/OEIS considered all training
activities proposed to occur in the
WMA, together for which they covered
all activities proposed for the GOA
Study Area. The Navy’s rulemaking/
LOA application described the activities
that are reasonably likely to result in the
MMPA-defined take of marine
mammals, all of which would occur in
the TMAA portion of the GOA Study
Area. The Navy determined that the two
stressors below could result in the
incidental taking of marine mammals.
NMFS has reviewed the Navy’s data and
analysis for the entire Study Area and
determined that it is complete and
accurate, and agrees that the following
stressors have the potential to result in
takes by harassment of marine mammals
from the Navy’s planned activities.
• Acoustics (sonar and other
transducers); and
• Explosives (explosive shock wave
and sound, assumed to encompass the
risk due to fragmentation).
The quantitative analysis process
used to estimate potential exposures to
marine mammals resulting from
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
acoustic and explosive stressors for the
Navy’s take request in the rulemaking/
LOA application and the 2020 GOA
DSEIS/OEIS is detailed in the technical
report titled Quantifying Acoustic
Impacts on Marine Mammals and Sea
Turtles: Methods and Analytical
Approach for Phase III Training and
Testing (U.S. Department of the Navy,
2018). The Navy Acoustic Effects Model
estimates acoustic and explosive effects
without taking mitigation into account;
therefore, the model overestimates
predicted impacts on marine mammals
within mitigation zones.
To account for mitigation for marine
species in the take estimates, the Navy
conducts a quantitative assessment of
mitigation. The Navy conservatively
quantifies the manner in which
procedural mitigation is expected to
reduce the risk for model-estimated PTS
for exposures to sonars and for modelestimated mortality for exposures to
explosives, based on species
sightability, observation area, visibility,
and the ability to exercise positive
control over the sound source. Where
the analysis indicates mitigation would
effectively reduce risk, the modelestimated PTS are considered reduced
to TTS and the model-estimated
mortalities are considered reduced to
injury, though, for training activities in
the GOA Study Area, no mortality or
non-auditory injury is anticipated, even
without consideration of planned
mitigation measures. For a complete
explanation of the process for assessing
the effects of mitigation, see the Navy’s
rulemaking/LOA application (Section 6:
Take Estimates for Marine Mammals,
and Section 11: Mitigation Measures)
and the technical report titled
Quantifying Acoustic Impacts on
Marine Mammals and Sea Turtles:
Methods and Analytical Approach for
Phase III Training and Testing (U.S.
Department of the Navy, 2018). The
extent to which the mitigation areas
reduce impacts on the affected species
is addressed separately in the
Preliminary Analysis and Negligible
Impact Determination section.
The Navy assesses the effectiveness of
its procedural mitigation measures on a
per-scenario basis for four factors: (1)
species sightability, (2) a Lookout’s
ability to observe the range to PTS (for
sonar and other transducers) and range
to mortality (for explosives, although for
this rule the Navy’s modeling indicated
that no mortality would occur), (3) the
portion of time when mitigation could
potentially be conducted during periods
of reduced daytime visibility (to include
inclement weather and high sea-state)
and the portion of time when mitigation
could potentially be conducted at night,
PO 00000
Frm 00063
Fmt 4701
Sfmt 4702
49717
and (4) the ability for sound sources to
be positively controlled (e.g., powered
down).
During training activities, there is
typically at least one, if not numerous,
support personnel involved in the
activity (e.g., range support personnel
aboard a torpedo retrieval boat or
support aircraft). In addition to the
Lookout posted for the purpose of
mitigation, these additional personnel
observe and disseminate marine species
sighting information amongst the units
participating in the activity whenever
possible as they conduct their primary
mission responsibilities. However, as a
conservative approach to assigning
mitigation effectiveness factors, the
Navy elected to only account for the
minimum number of required Lookouts
used for each activity; therefore, the
mitigation effectiveness factors may
underestimate the likelihood that some
marine mammals may be detected
during activities that are supported by
additional personnel who may also be
observing the mitigation zone.
For a rulemaking where NMFS and
the Navy determine that the planned
activities, such as use of explosives,
could cause mortality, the Navy would
use the equations in the below sections
to calculate the reduction in modelestimated mortality impacts due to
implementing procedural mitigation.
Equation 1:
Mitigation Effectiveness = Species
Sightability × Visibility ×
Observation Area × Positive Control
Species Sightability is the ability to
detect marine mammals and is
dependent on the animal’s presence at
the surface and the characteristics of the
animal that influence its sightability.
The Navy considered applicable data
from the best available science to
numerically approximate the
sightability of marine mammals and
determined the standard ‘‘detection
probability’’ referred to as g(0) is most
appropriate. Also, Visibility = 1¥ sum
of individual visibility reduction
factors; Observation Area = portion of
impact range that can be continuously
observed during an event; and Positive
Control = positive control factor of all
sound sources involving mitigation. For
further details on these mitigation
effectiveness factors please refer to the
technical report titled Quantifying
Acoustic Impacts on Marine Mammals
and Sea Turtles: Methods and
Analytical Approach for Phase III
Training and Testing (U.S. Department
of the Navy, 2018).
To quantify the number of marine
mammals predicted to be sighted by
Lookouts in the injury zone during
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49718
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
implementation of procedural
mitigation for sonar and other
transducers, the species sightability is
multiplied by the mitigation
effectiveness scores and number of
model-estimated PTS impacts, as shown
in the equation below:
Equation 2:
Number of Animals Sighted by Lookouts
= Mitigation Effectiveness × Model
¥ Estimated Impacts
The marine mammals sighted by
Lookouts in the injury zone during
implementation of mitigation, as
calculated by the equation above, would
not be exposed to these higher level
impacts. To quantify the number of
marine mammals predicted to be
sighted by Lookouts in the mortality
zone during implementation of
procedural mitigation during events
using explosives (if any mortality were
anticipated to occur), the species
sightability is multiplied by the
mitigation effectiveness scores and
number of model-estimated mortality
impacts, as shown in equation 1 above.
The marine mammals predicted to be
sighted in the mortality zone by
Lookouts during implementation of
procedural mitigation, as calculated by
the above equation 2, are not predicted
to be exposed in these ranges. The Navy
corrects the category of predicted
impact for the number of animals
sighted within the mitigation zone, but
does not modify the total number of
animals predicted to experience impacts
from the scenario. For example, the
number of animals sighted (i.e., number
of animals that will avoid mortality) is
first subtracted from the modelpredicted mortality impacts, and then
added to the model-predicted injurious
impacts.
The NAEMO model overestimates the
number of marine mammals that would
be exposed to sound sources that could
cause PTS because the model does not
consider horizontal movement of
animats, including avoidance of high
intensity sound exposures. Therefore,
the potential for animal avoidance is
considered separately. At close ranges
and high sound levels, avoidance of the
area immediately around the sound
source is one of the assumed behavioral
responses for marine mammals. Animal
avoidance refers to the movement out of
the immediate injury zone for
subsequent exposures, not wide-scale
area avoidance. Various researchers
have demonstrated that cetaceans can
perceive the location and movement of
a sound source (e.g., vessel, seismic
source, etc.) relative to their own
location and react with responsive
movement away from the source, often
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
at distances of 1 km or more (Au and
Perryman, 1982; Jansen et al., 2010;
Richardson et al., 1995; Tyack et al.,
2011; Watkins, 1986; Wu¨rsig et al.,
1998). A marine mammal’s ability to
avoid a sound source and reduce its
cumulative sound energy exposure
would reduce risk of both PTS and TTS.
However, the quantitative analysis
conservatively only considers the
potential to reduce some instances of
PTS by accounting for marine mammals
swimming away to avoid repeated highlevel sound exposures. All reductions in
PTS impacts from likely avoidance
behaviors are instead considered TTS
impacts.
NMFS coordinated with the Navy in
the development of this quantitative
method to address the effects of
procedural mitigation on acoustic and
explosive exposures and takes, and
NMFS independently reviewed and
concurs with the Navy that it is
appropriate to incorporate the
quantitative assessment of mitigation
into the take estimates based on the best
available science. We reiterate, however,
that no mortality was modeled for the
GOA TMAA activities, and as stated
above, the Navy does not propose the
use of sonar and other transducers and
explosives in the WMA. Therefore, this
method was not applied here, as it
relates to modeled mortality. This
method was applied to potential takes
by PTS resulting from sonar and other
transducers in the TMAA, but not for
the use of explosives. For additional
information on the quantitative analysis
process and mitigation measures, refer
to the technical report titled Quantifying
Acoustic Impacts on Marine Mammals
and Sea Turtles: Methods and
Analytical Approach for Phase III
Training and Testing (U.S. Department
of the Navy, 2018) and Chapter 6 (Take
Estimates for Marine Mammals) and
Chapter 11 (Mitigation Measures) of the
Navy’s rulemaking/LOA application.
As a general matter, NMFS does not
prescribe the methods for estimating
take for any applicant, but we review
and ensure that applicants use the best
available science, and methodologies
that are logical and technically sound.
Applicants may use different methods
of calculating take (especially when
using models) and still get to a result
that is representative of the best
available science and that allows for a
rigorous and accurate evaluation of the
effects on the affected populations.
There are multiple pieces of the Navy
take estimation methods—propagation
models, animat movement models, and
behavioral thresholds, for example.
NMFS evaluates the acceptability of
these pieces as they evolve and are used
PO 00000
Frm 00064
Fmt 4701
Sfmt 4702
in different rules and impact analyses.
Some of the pieces of the Navy’s take
estimation process have been used in
Navy incidental take rules since 2009
and have undergone multiple public
comment processes; all of them have
undergone extensive internal Navy
review, and all of them have undergone
comprehensive review by NMFS, which
has sometimes resulted in modifications
to methods or models.
The Navy uses rigorous review
processes (verification, validation, and
accreditation processes; peer and public
review) to ensure the data and
methodology it uses represent the best
available science. For instance, the
NAEMO model is the result of a NMFSled Center for Independent Experts (CIE)
review of the components used in
earlier models. The acoustic
propagation component of the NAEMO
model (CASS/GRAB) is accredited by
the Oceanographic and Atmospheric
Master Library (OAML), and many of
the environmental variables used in the
NAEMO model come from approved
OAML databases and are based on insitu data collection. The animal density
components of the NAEMO model are
base products of the NMSDD, which
includes animal density components
that have been validated and reviewed
by a variety of scientists from NMFS
Science Centers and academic
institutions. Several components of the
model, for example the Duke University
habitat-based density models, have been
published in peer reviewed literature.
Others like the Atlantic Marine
Assessment Program for Protected
Species, which was conducted by
NMFS Science Centers, have undergone
quality assurance and quality control
(QA/QC) processes. Finally, the
NAEMO model simulation components
underwent QA/QC review and
validation for model parts such as the
scenario builder, acoustic builder,
scenario simulator, etc., conducted by
qualified statisticians and modelers to
ensure accuracy. Other models and
methodologies have gone through
similar review processes.
In summary, we believe the Navy’s
methods, including the underlying
NAEMO modeling and the method for
incorporating mitigation and avoidance,
are the most appropriate methods for
predicting non-auditory injury, PTS,
TTS, and behavioral disturbance. But
even with the consideration of
mitigation and avoidance, given some of
the more conservative components of
the methodology (e.g., the thresholds do
not consider ear recovery between
pulses), we would describe the
application of these methods as
identifying the maximum number of
E:\FR\FM\11AUP2.SGM
11AUP2
49719
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
instances in which marine mammals
would be reasonably expected to be
taken through non-auditory injury, PTS,
TTS, or behavioral disturbance.
Summary of Requested Take From
Training Activities
Based on the methods discussed in
the previous sections and the Navy’s
model and quantitative assessment of
mitigation, the Navy provided its take
estimate and request for authorization of
takes incidental to the use of acoustic
and explosive sources for training
activities both annually (based on the
maximum number of activities that
could occur per 12-month period) and
over the 7-year period covered by the
Navy’s rulemaking/LOA application.
The following species/stocks present in
the TMAA were modeled by the Navy
and estimated to have 0 takes of any
type from any activity source: Western
North Pacific stock of humpback whale;
Eastern North Pacific and Western
North Pacific stocks of gray whales;
Eastern North Pacific Alaska Resident
and AT1 Transient stocks of killer
whales; Gulf of Alaska and Southeast
Alaska stocks of harbor porpoises; U.S.
stock of California sea lion; Eastern U.S.
and Western U.S. stock of Steller sea
lion; Cook Inlet/Shelikof Strait, North
Kodiak, Prince William Sound, and
South Kodiak stocks of harbor seals, and
Alaska stock of Ribbon seals.
The Phase II rule (82 FR 19530; April
26, 2017), valid from April 2017 to April
2022, authorized Level B harassment
take of the Eastern North Pacific Alaska
Resident stock of killer whales, Gulf of
Alaska and Southeast Alaska stocks of
harbor porpoise, California sea lion,
Eastern U.S. and Western U.S. stock of
Steller sea lion, and South Kodiak and
Prince William Sound stocks of harbor
seal. Takes of these stocks in Phase II
were all expected to occur as a result of
exposure to sonar activity, rather than
explosive use. Inclusion of new density/
distribution information and updated
BRFs and corresponding cut-offs
resulted in 0 estimated takes for these
species and stocks in this rulemaking
for Phase III.
NMFS has reviewed the Navy’s data,
methodology, and analysis for the
current phase of rulemaking (Phase III)
and determined that it is complete and
accurate. However, NMFS has
conservatively proposed to include
incidental take of the Western North
Pacific stock of humpback whale and
Eastern North Pacific stock of gray
whale, for the following reasons. For the
Western North Pacific stock of
humpback whale, in calculating takes
by Level B harassment from sonar in
Phase III, the application of the Phase III
BRFs with corresponding cut-offs (20
km for mysticetes), in addition to the
stock guild breakout which assigns 0.05
percent of the take of humpback whales
to the Western North Pacific stock,
generated a near-zero result, which the
Navy rounded to zero in its rulemaking/
LOA application. However, NMFS
authorized take of one Western North
Pacific humpback whale in the Phase II
LOA, and, given that they do occur in
the area, NMFS is conservatively
proposing to authorize take by Level B
harassment of one group (3 animals)
annually in this Phase III rulemaking.
The annual take estimate of 3 animals
reflects the average group size of on and
off-effort survey sightings of humpback
whales reported in Rone et al. (2017).
For the Eastern North Pacific stock of
gray whales, application of the Phase III
BRFs with corresponding cut-offs (20
km for mysticetes) resulted in true zero
takes by Level B harassment for Phase
III. However, Palacios et al. (2021)
reported locations of three tagged gray
whales within the TMAA as well as
tracks of two additional gray whales that
crossed the TMAA, and as noted
previously, the TMAA overlaps with the
gray whale migratory corridor BIA
(November–January, southbound;
March–May, northbound). As such,
NMFS is conservatively proposing to
authorize take by Level B harassment of
one group (4 animals) of Eastern North
Pacific gray whales annually in this
Phase III rulemaking. The annual take
estimate of 4 animals reflects the
average group sizes of on and off-effort
survey sightings of gray whales
(excluding an outlier of an estimated 25
gray whales in one group) reported in
Rone et al. (2017).
For all other species and stocks,
NMFS agrees that the estimates for
incidental takes by harassment from all
sources requested for authorization are
the maximum number of instances in
which marine mammals are reasonably
expected to be taken. NMFS also agrees
that no mortality or serious injury is
anticipated to occur, and no lethal take
is proposed to be authorized.
Estimated Harassment Take From
Training Activities
For the Navy’s training activities,
Table 30 summarizes the Navy’s take
estimate and request and the maximum
annual and 7-year total amount and type
of Level A harassment and Level B
harassment for the 7-year period that
NMFS anticipates is reasonably likely to
occur (including the incidental take of
Western North Pacific stock of
humpback whale and Eastern North
Pacific stock of gray whale, discussed
above) by species and stock. Note that
take by Level B harassment includes
both behavioral disruption and TTS.
Tables 6–10 through 6–24 (sonar and
other transducers) and 6–41 through 6–
49 (explosives) in Section 6 of the
Navy’s rulemaking/LOA application
provide the comparative amounts of
TTS and behavioral disruption for each
species and stock annually, noting that
if a modeled marine mammal was
‘‘taken’’ through exposure to both TTS
and behavioral disruption in the model,
it was recorded as a TTS.
TABLE 30—ANNUAL AND 7-YEAR TOTAL SPECIES/STOCK-SPECIFIC TAKE ESTIMATES PROPOSED FOR AUTHORIZATION
FROM ACOUSTIC AND EXPLOSIVE SOUND SOURCE EFFECTS FOR ALL TRAINING ACTIVITIES IN THE TMAA
Annual
Species
7-year total
Stock
Level B
Level A
Level B
Level A
lotter on DSK11XQN23PROD with PROPOSALS2
Order Cetacea
Suborder Mysticeti (baleen whales)
Family Balaenidae (right whales):
North Pacific right whale * ..........
Family Balaenopteridae (rorquals):
Humpback whale ........................
Blue whale * ................................
Fin whale * ..................................
VerDate Sep<11>2014
18:10 Aug 10, 2022
Eastern North Pacific .......................
3
0
21
0
California, Oregon, & Washington *
Central North Pacific * ......................
Western North Pacific * ....................
Central North Pacific ........................
Eastern North Pacific .......................
Northeast Pacific ..............................
10
79
a3
3
36
1,242
0
0
0
0
0
2
70
553
a 21
21
252
8,694
0
0
0
0
0
14
Jkt 256001
PO 00000
Frm 00065
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
49720
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
TABLE 30—ANNUAL AND 7-YEAR TOTAL SPECIES/STOCK-SPECIFIC TAKE ESTIMATES PROPOSED FOR AUTHORIZATION
FROM ACOUSTIC AND EXPLOSIVE SOUND SOURCE EFFECTS FOR ALL TRAINING ACTIVITIES IN THE TMAA—Continued
Annual
Species
7-year total
Stock
Level B
Sei whale * ..................................
Minke whale ...............................
Family Eschrichtiidae (gray whale):
Gray whale .................................
Level A
Level B
Level A
Eastern North Pacific .......................
Alaska ..............................................
37
50
0
0
259
350
0
0
Eastern North Pacific .......................
a4
0
a 28
0
Suborder Odontoceti (toothed whales)
Family Delphinidae (dolphins):
Killer whale .................................
Pacific white-sided dolphin .........
Family Phocoenidae (porpoises):
Dall’s porpoise ............................
Family Physeteridae (sperm whale):
Sperm whale * ............................
Family Ziphiidae (beaked whales):
Baird’s beaked whale .................
Cuvier’s beaked whale ...............
Stejneger’s beaked whale ..........
Eastern North Pacific, Offshore .......
Gulf of Alaska, Aleutian Island, &
Bering Sea Transient.
North Pacific ....................................
81
143
0
0
567
1,001
0
0
1,574
0
11,018
0
Alaska ..............................................
9,287
64
65,009
448
North Pacific ....................................
112
0
784
0
Alaska ..............................................
Alaska ..............................................
Alaska ..............................................
106
433
482
0
0
0
742
3,031
3,374
0
0
0
Eastern Pacific .................................
California ..........................................
3,003
61
0
0
21,021
427
0
0
California ..........................................
2,547
8
17,829
56
Order Carnivora
Suborder Pinnipedia
Family Otarridae:
Northern fur seal ........................
Family Phocidae (true seals):
Northern elephant seal ...............
* ESA-listed species and stocks within the GOA Study Area.
a The Navy’s Acoustic Effects Model estimated zero takes for each of these stocks. However, NMFS conservatively proposes to authorize take
by Level B harassment of one group of Western North Pacific humpback whale and one group of Eastern North Pacific gray whale. The annual
take estimates reflect the average group sizes of on and off-effort survey sightings of humpback whale and gray whale (excluding an outlier of an
estimated 25 gray whales in one group) reported in Rone et al. (2017).
lotter on DSK11XQN23PROD with PROPOSALS2
Proposed Mitigation Measures
Under section 101(a)(5)(A) of the
MMPA, NMFS must set forth the
permissible methods of taking pursuant
to the activity, and other means of
effecting the least practicable adverse
impact on the species or stocks and
their habitat, paying particular attention
to rookeries, mating grounds, and areas
of similar significance, and on the
availability of the species or stocks for
subsistence uses (‘‘least practicable
adverse impact’’). NMFS does not have
a regulatory definition for least
practicable adverse impact. The 2004
NDAA amended the MMPA as it relates
to military readiness activities and the
incidental take authorization process
such that a determination of ‘‘least
practicable adverse impact’’ shall
include consideration of personnel
safety, practicality of implementation,
and impact on the effectiveness of the
military readiness activity.
In Conservation Council for Hawaii v.
National Marine Fisheries Service, 97 F.
Supp. 3d 1210, 1229 (D. Haw. 2015), the
Court stated that NMFS ‘‘appear[s] to
think [it] satisf[ies] the statutory ‘least
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
practicable adverse impact’ requirement
with a ‘negligible impact’ finding.’’ In
2016, expressing similar concerns in a
challenge to a U.S. Navy Surveillance
Towed Array Sensor System Low
Frequency Active Sonar (SURTASS
LFA) incidental take rule (77 FR 50290),
the Ninth Circuit Court of Appeals in
Natural Resources Defense Council
(NRDC) v. Pritzker, 828 F.3d 1125, 1134
(9th Cir. 2016), stated ‘‘[c]ompliance
with the ‘negligible impact’ requirement
does not mean there [is] compliance
with the ‘least practicable adverse
impact’ standard.’’ As the Ninth Circuit
noted in its opinion, however, the Court
was interpreting the statute without the
benefit of NMFS’ formal interpretation.
We state here explicitly that NMFS is in
full agreement that the ‘‘negligible
impact’’ and ‘‘least practicable adverse
impact’’ requirements are distinct, even
though both statutory standards refer to
species and stocks. With that in mind,
we provide further explanation of our
interpretation of least practicable
adverse impact, and explain what
distinguishes it from the negligible
impact standard. This discussion is
PO 00000
Frm 00066
Fmt 4701
Sfmt 4702
consistent with previous rules we have
published, such as the Navy’s HSTT
rule (83 FR 66846; December 27, 2018),
AFTT rule (84 FR 70712; December 23,
2019), Mariana Islands Training and
Testing (MITT) rule (85 FR 46302; July
31, 2020), and the Northwest Training
and Testing (NWTT) rule (85 FR 72312;
November 12, 2020).
Before NMFS can issue incidental
take regulations under section
101(a)(5)(A) of the MMPA, it must make
a finding that the total taking will have
a ‘‘negligible impact’’ on the affected
‘‘species or stocks’’ of marine mammals.
NMFS’ and U.S. Fish and Wildlife
Service’s implementing regulations for
section 101(a)(5) both define ‘‘negligible
impact’’ as an impact resulting from the
specified activity that cannot be
reasonably expected to, and is not
reasonably likely to, adversely affect the
species or stock through effects on
annual rates of recruitment or survival
(50 CFR 216.103 and 50 CFR 18.27(c)).
Recruitment (i.e., reproduction) and
survival rates are used to determine
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
population growth rates 2 and, therefore
are considered in evaluating population
level impacts.
As stated in the preamble to the
proposed rule for the MMPA incidental
take implementing regulations (53 FR
8473; March 15, 1988), not every
population-level impact violates the
negligible impact requirement. The
negligible impact standard does not
require a finding that the anticipated
take will have ‘‘no effect’’ on population
numbers or growth rates: the statutory
standard does not require that the same
recovery rate be maintained, rather it
requires that no significant effect on
annual rates of recruitment or survival
occurs. The key factor is the significance
of the level of impact on rates of
recruitment or survival. (54 FR 40338,
40341–42; September 29, 1989).
While some level of impact on
population numbers or growth rates of
a species or stock may occur and still
satisfy the negligible impact
requirement—even without
consideration of mitigation—the least
practicable adverse impact provision
separately requires NMFS to prescribe
means of effecting the least practicable
adverse impact on the species or stock
and its habitat, paying particular
attention to rookeries, mating grounds,
and areas of similar significance (50
CFR 216.102(b)), which are typically
identified as the subject of mitigation
measures.3
The negligible impact and least
practicable adverse impact standards in
the MMPA both call for evaluation at
the level of the ‘‘species or stock.’’ The
MMPA does not define the term
‘‘species.’’ However, Merriam-Webster
Dictionary defines ‘‘species’’ to include
‘‘related organisms or populations
potentially capable of interbreeding.’’
See www.merriam-webster.com/
dictionary/species (emphasis added).
Section 3(11) of the MMPA defines
‘‘stock’’ as a group of marine mammals
of the same species or smaller taxa in a
common spatial arrangement that
interbreed when mature. The definition
of ‘‘population’’ is a group of
interbreeding organisms that represents
the level of organization at which
speciation begins. www.merriamwebster.com/dictionary/population. The
definition of ‘‘population’’ is strikingly
similar to the MMPA’s definition of
‘‘stock,’’ with both involving groups of
2A
growth rate can be positive, negative, or flat.
NMFS also must prescribe means of
effecting the least practicable adverse impact on the
availability of the species or stocks for subsistence
uses, when applicable. See the Subsistence Harvest
of Marine Mammals section for separate discussion
of the effects of the specified activities on Alaska
Native subsistence use.
3 Separately,
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
individuals that belong to the same
species and are located in a manner that
allows for interbreeding. In fact, under
MMPA section 3(11), the statutory term
‘‘stock’’ in the MMPA is interchangeable
with the statutory term ‘‘population
stock.’’ Both the negligible impact
standard and the least practicable
adverse impact standard call for
evaluation at the level of the species or
stock, and the terms ‘‘species’’ and
‘‘stock’’ both relate to populations;
therefore, it is appropriate to view both
the negligible impact standard and the
least practicable adverse impact
standard as having a population-level
focus.
This interpretation is consistent with
Congress’ statutory findings for enacting
the MMPA, nearly all of which are most
applicable at the species or stock (i.e.,
population) level. See MMPA section 2
(finding that it is species and population
stocks that are or may be in danger of
extinction or depletion; that it is species
and population stocks that should not
diminish beyond being significant
functioning elements of their
ecosystems; and that it is species and
population stocks that should not be
permitted to diminish below their
optimum sustainable population level).
Annual rates of recruitment (i.e.,
reproduction) and survival are the key
biological metrics used in the evaluation
of population-level impacts, and
accordingly these same metrics are also
used in the evaluation of population
level impacts for the least practicable
adverse impact standard.
Recognizing this common focus of the
least practicable adverse impact and
negligible impact provisions on the
‘‘species or stock’’ does not mean we
conflate the two standards; despite some
common statutory language, we
recognize the two provisions are
different and have different functions.
First, a negligible impact finding is
required before NMFS can issue an
incidental take authorization. Although
it is acceptable to use the mitigation
measures to reach a negligible impact
finding (see 50 CFR 216.104(c)), no
amount of mitigation can enable NMFS
to issue an incidental take authorization
for an activity that still would not meet
the negligible impact standard.
Moreover, even where NMFS can reach
a negligible impact finding—which we
emphasize does allow for the possibility
of some ‘‘negligible’’ population-level
impact—the agency must still prescribe
measures that will affect the least
practicable amount of adverse impact
upon the affected species or stock.
Section 101(a)(5)(A)(i)(II) requires
NMFS to issue, in conjunction with its
authorization, binding—and
PO 00000
Frm 00067
Fmt 4701
Sfmt 4702
49721
enforceable—restrictions (in the form of
regulations) setting forth how the
activity must be conducted, thus
ensuring the activity has the ‘‘least
practicable adverse impact’’ on the
affected species or stocks. In situations
where mitigation is specifically needed
to reach a negligible impact
determination, section 101(a)(5)(A)(i)(II)
also provides a mechanism for ensuring
compliance with the ‘‘negligible
impact’’ requirement. Finally, the least
practicable adverse impact standard also
requires consideration of measures for
marine mammal habitat, with particular
attention to rookeries, mating grounds,
and other areas of similar significance,
and for subsistence impacts, whereas
the negligible impact standard is
concerned solely with conclusions
about the impact of an activity on
annual rates of recruitment and
survival.4 In NRDC v. Pritzker, the Court
stated, ‘‘[t]he statute is properly read to
mean that even if population levels are
not threatened significantly, still the
agency must adopt mitigation measures
aimed at protecting marine mammals to
the greatest extent practicable in light of
military readiness needs.’’ Pritzker at
1134 (emphases added). This statement
is consistent with our understanding
stated above that even when the effects
of an action satisfy the negligible impact
standard (i.e., in the Court’s words,
‘‘population levels are not threatened
significantly’’), still the agency must
prescribe mitigation under the least
practicable adverse impact standard.
However, as the statute indicates, the
focus of both standards is ultimately the
impact on the affected ‘‘species or
stock,’’ and not solely focused on or
directed at the impact on individual
marine mammals.
We have carefully reviewed and
considered the Ninth Circuit’s opinion
in NRDC v. Pritzker in its entirety.
While the Court’s reference to ‘‘marine
mammals’’ rather than ‘‘marine mammal
species or stocks’’ in the italicized
language above might be construed as
holding that the least practicable
adverse impact standard applies at the
individual ‘‘marine mammal’’ level, i.e.,
that NMFS must require mitigation to
minimize impacts to each individual
marine mammal unless impracticable,
we believe such an interpretation
reflects an incomplete appreciation of
the Court’s holding. In our view, the
opinion as a whole turned on the
Court’s determination that NMFS had
not given separate and independent
4 Outside of the military readiness context,
mitigation may also be appropriate to ensure
compliance with the ‘‘small numbers’’ language in
MMPA sections 101(a)(5)(A) and (D).
E:\FR\FM\11AUP2.SGM
11AUP2
49722
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
meaning to the least practicable adverse
impact standard apart from the
negligible impact standard, and further,
that the Court’s use of the term ‘‘marine
mammals’’ was not addressing the
question of whether the standard
applies to individual animals as
opposed to the species or stock as a
whole. We recognize that, while
consideration of mitigation can play a
role in a negligible impact
determination, consideration of
mitigation measures extends beyond
that analysis. In evaluating what
mitigation measures are appropriate,
NMFS considers the potential impacts
of the specified activities, the
availability of measures to minimize
those potential impacts, and the
practicability of implementing those
measures, as we describe below.
Implementation of Least Practicable
Adverse Impact Standard
Given the NRDC v. Pritzker decision,
we discuss here how we determine
whether a measure or set of measures
meets the ‘‘least practicable adverse
impact’’ standard. Our separate analysis
of whether the take anticipated to result
from Navy’s activities meets the
‘‘negligible impact’’ standard appears in
the Preliminary Analysis and Negligible
Impact Determination section below.
Our evaluation of potential mitigation
measures includes consideration of two
primary factors:
(1) The manner in which, and the
degree to which, implementation of the
potential measure(s) is expected to
reduce adverse impacts to marine
mammal species or stocks, their habitat,
or their availability for subsistence uses
(where relevant). This analysis
considers such things as the nature of
the potential adverse impact (such as
likelihood, scope, and range), the
likelihood that the measure will be
effective if implemented, and the
likelihood of successful
implementation; and
(2) The practicability of the
measure(s) for applicant
implementation. Practicability of
implementation may consider such
things as cost, impact on activities, and,
in the case of a military readiness
activity, specifically considers
personnel safety, practicality of
implementation, and impact on the
effectiveness of the military readiness
activity.
While the language of the least
practicable adverse impact standard
calls for minimizing impacts to affected
species or stocks, we recognize that the
reduction of impacts to those species or
stocks accrues through the application
of mitigation measures that limit
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
impacts to individual animals.
Accordingly, NMFS’ analysis focuses on
measures that are designed to avoid or
minimize impacts on individual marine
mammals that are likely to increase the
probability or severity of populationlevel effects.
While direct evidence of impacts to
species or stocks from a specified
activity is rarely available, and
additional study is still needed to
understand how specific disturbance
events affect the fitness of individuals of
certain species, there have been
improvements in understanding the
process by which disturbance effects are
translated to the population. With
recent scientific advancements (both
marine mammal energetic research and
the development of energetic
frameworks), the relative likelihood or
degree of impacts on species or stocks
may often be inferred given a detailed
understanding of the activity, the
environment, and the affected species or
stocks—and the best available science
has been used here. This same
information is used in the development
of mitigation measures and helps us
understand how mitigation measures
contribute to lessening effects (or the
risk thereof) to species or stocks. We
also acknowledge that there is always
the potential that new information, or a
new recommendation, could become
available in the future and necessitate
reevaluation of mitigation measures
(which may be addressed through
adaptive management) to see if further
reductions of population impacts are
possible and practicable.
In the evaluation of specific measures,
the details of the specified activity will
necessarily inform each of the two
primary factors discussed above
(expected reduction of impacts and
practicability), and are carefully
considered to determine the types of
mitigation that are appropriate under
the least practicable adverse impact
standard. Analysis of how a potential
mitigation measure may reduce adverse
impacts on a marine mammal stock or
species, consideration of personnel
safety, practicality of implementation,
and consideration of the impact on
effectiveness of military readiness
activities are not issues that can be
meaningfully evaluated through a yes/
no lens. The manner in which, and the
degree to which, implementation of a
measure is expected to reduce impacts,
as well as its practicability in terms of
these considerations, can vary widely.
For example, a time/area restriction
could be of very high value for
decreasing population-level impacts
(e.g., avoiding disturbance of feeding
females in an area of established
PO 00000
Frm 00068
Fmt 4701
Sfmt 4702
biological importance) or it could be of
lower value (e.g., decreased disturbance
in an area of high productivity but of
less biological importance). Regarding
practicability, a measure might involve
restrictions in an area or time that
impede the Navy’s ability to certify a
strike group (higher impact on mission
effectiveness), or it could mean delaying
a small in-port training event by 30
minutes to avoid exposure of a marine
mammal to injurious levels of sound
(lower impact). A responsible
evaluation of ‘‘least practicable adverse
impact’’ will consider the factors along
these realistic scales. Accordingly, the
greater the likelihood that a measure
will contribute to reducing the
probability or severity of adverse
impacts to the species or stock or its
habitat, the greater the weight that
measure is given when considered in
combination with practicability to
determine the appropriateness of the
mitigation measure, and vice versa. We
discuss consideration of these factors in
greater detail below.
1. Reduction of adverse impacts to
marine mammal species or stocks and
their habitat. The emphasis given to a
measure’s ability to reduce the impacts
on a species or stock considers the
degree, likelihood, and context of the
anticipated reduction of impacts to
individuals (and how many individuals)
as well as the status of the species or
stock.
The ultimate impact on any
individual from a disturbance event
(which informs the likelihood of
adverse species- or stock-level effects) is
dependent on the circumstances and
associated contextual factors, such as
duration of exposure to stressors.
Though any proposed mitigation needs
to be evaluated in the context of the
specific activity and the species or
stocks affected, measures with the
following types of effects have greater
value in reducing the likelihood or
severity of adverse species- or stocklevel impacts: avoiding or minimizing
injury or mortality; limiting interruption
of known feeding, breeding, mother/
young, or resting behaviors; minimizing
the abandonment of important habitat
(temporally and spatially); minimizing
the number of individuals subjected to
these types of disruptions; and limiting
degradation of habitat. Mitigating these
types of effects is intended to reduce the
likelihood that the activity will result in
energetic or other types of impacts that
are more likely to result in reduced
reproductive success or survivorship. It
is also important to consider the degree
of impacts that are expected in the
absence of mitigation in order to assess
the added value of any potential
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
measures. Finally, because the least
practicable adverse impact standard
gives NMFS discretion to weigh a
variety of factors when determining
appropriate mitigation measures and
because the focus of the standard is on
reducing impacts at the species or stock
level, the least practicable adverse
impact standard does not compel
mitigation for every kind of take, or
every individual taken, if that mitigation
is unlikely to meaningfully contribute to
the reduction of adverse impacts on the
species or stock and its habitat, even
when practicable for implementation by
the applicant.
The status of the species or stock is
also relevant in evaluating the
appropriateness of potential mitigation
measures in the context of least
practicable adverse impact. The
following are examples of factors that
may (either alone, or in combination)
result in greater emphasis on the
importance of a mitigation measure in
reducing impacts on a species or stock:
the stock is known to be decreasing or
status is unknown, but believed to be
declining; the known annual mortality
(from any source) is approaching or
exceeding the potential biological
removal (PBR) level (as defined in
MMPA section 3(20)); the affected
species or stock is a small, resident
population; or the stock is involved in
a UME or has other known
vulnerabilities, such as recovering from
an oil spill.
Habitat mitigation, particularly as it
relates to rookeries, mating grounds, and
areas of similar significance, is also
relevant to achieving the standard and
can include measures such as reducing
impacts of the activity on known prey
utilized in the activity area or reducing
impacts on physical habitat. As with
species- or stock-related mitigation, the
emphasis given to a measure’s ability to
reduce impacts on a species or stock’s
habitat considers the degree, likelihood,
and context of the anticipated reduction
of impacts to habitat. Because habitat
value is informed by marine mammal
presence and use, in some cases there
may be overlap in measures for the
species or stock and for use of habitat.
We consider available information
indicating the likelihood of any measure
to accomplish its objective. If evidence
shows that a measure has not typically
been effective nor successful, then
either that measure should be modified
or the potential value of the measure to
reduce effects should be lowered.
2. Practicability. Factors considered
may include cost, impact on activities,
and, in the case of a military readiness
activity, will include personnel safety,
practicality of implementation, and
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
impact on the effectiveness of the
military readiness activity (see MMPA
section 101(a)(5)(A)(ii)).
Assessment of Mitigation Measures for
the GOA Study Area
NMFS has fully reviewed the
specified activities and the mitigation
measures included in the Navy’s
rulemaking/LOA application, the 2020
GOA DSEIS/OEIS, and the 2022
Supplement to the 2020 GOA DSEIS/
OEIS to determine if the mitigation
measures would result in the least
practicable adverse impact on marine
mammals and their habitat. NMFS
worked with the Navy in the
development of the Navy’s initially
proposed measures, which are informed
by years of implementation and
monitoring. A complete discussion of
the Navy’s evaluation process used to
develop, assess, and select mitigation
measures, which was informed by input
from NMFS, can be found in Chapter 5
(Mitigation) of the 2020 GOA DSEIS/
OEIS. The process described in Chapter
5 (Mitigation) of the 2020 GOA DSEIS/
OEIS robustly supported NMFS’
independent evaluation of whether the
mitigation measures would meet the
least practicable adverse impact
standard, including the addition of the
Continental Shelf and Slope Mitigation
Area presented in the February 2022
second updated application and
analyzed in the 2022 Supplement to the
2020 GOA DSEIS/OEIS. The Navy
would be required to implement the
mitigation measures identified in this
rule for the full 7 years to avoid or
reduce potential impacts from acoustic
and explosive stressors.
As a general matter, where an
applicant proposes measures that are
likely to reduce impacts to marine
mammals, the fact that they are
included in the application indicates
that the measures are practicable, and it
is not necessary for NMFS to conduct a
detailed analysis of the measures the
applicant proposed (rather, they are
simply included). However, it is still
necessary for NMFS to consider whether
there are additional practicable
measures that would meaningfully
reduce the probability or severity of
impacts that could affect reproductive
success or survivorship.
Overall the Navy has agreed to
procedural mitigation measures that
would reduce the probability and/or
severity of impacts expected to result
from acute exposure to acoustic sources
or explosives, ship strike, and impacts
to marine mammal habitat. Specifically,
the Navy would use a combination of
delayed starts, powerdowns, and
shutdowns to avoid mortality or serious
PO 00000
Frm 00069
Fmt 4701
Sfmt 4702
49723
injury, minimize the likelihood or
severity of PTS or other injury, and
reduce instances of TTS or more severe
behavioral disruption caused by
acoustic sources or explosives. The
Navy would also implement multiple
time/area restrictions that would reduce
take of marine mammals in areas or at
times where they are known to engage
in important behaviors, such as
foraging, where the disruption of those
behaviors would have a higher
probability of resulting in impacts on
reproduction or survival of individuals
that could lead to population-level
impacts.
The Navy assessed the practicability
of the proposed measures in the context
of personnel safety, practicality of
implementation, and their impacts on
the Navy’s ability to meet their Title 10
requirements and found that the
measures are supportable. As described
in more detail below, NMFS has
independently evaluated the measures
the Navy proposed in the manner
described earlier in this section (i.e., in
consideration of their ability to reduce
adverse impacts on marine mammal
species and their habitat and their
practicability for implementation). We
have determined that the measures
would significantly and adequately
reduce impacts on the affected marine
mammal species and stocks and their
habitat and, further, be practicable for
Navy implementation. Therefore, the
mitigation measures assure that the
Navy’s activities would have the least
practicable adverse impact on the
species or stocks and their habitat.
The Navy also evaluated numerous
measures in the 2020 GOA DSEIS/OEIS
that were not included in the Navy’s
rulemaking/LOA application, and
NMFS independently reviewed and
preliminarily concurs with the Navy’s
analysis that their inclusion was not
appropriate under the least practicable
adverse impact standard based on our
assessment. The Navy considered these
additional potential mitigation measures
in two groups. First, Chapter 5
(Mitigation) of the 2020 GOA DSEIS/
OEIS, in the Measures Considered but
Eliminated section, includes an analysis
of an array of different types of
mitigation that have been recommended
over the years by non-governmental
organizations or the public, through
scoping or public comment on
environmental compliance documents.
As described in Chapter 5 (Mitigation)
of the 2020 GOA DSEIS/OEIS, the Navy
considered reducing its overall amount
of training, reducing explosive use,
modifying its sound sources, completely
replacing live training with computer
simulation, and including time of day
E:\FR\FM\11AUP2.SGM
11AUP2
49724
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
restrictions. Many of these mitigation
measures could potentially reduce the
number of marine mammals taken, via
direct reduction of the activities or
amount of sound energy put in the
water. However, as described in Chapter
5 (Mitigation) of the 2020 GOA DSEIS/
OEIS, the Navy needs to train in the
conditions in which it fights—and these
types of modifications fundamentally
change the activity in a manner that
would not support the purpose and
need for the training (i.e., are entirely
impracticable) and therefore are not
considered further. NMFS finds the
Navy’s explanation for why adoption of
these recommendations would
unacceptably undermine the purpose of
the training persuasive. After
independent review, NMFS finds the
Navy’s judgment on the impacts of these
potential mitigation measures to
personnel safety, practicality of
implementation, and the effectiveness of
training persuasive, and for these
reasons, NMFS finds that these
measures do not meet the least
practicable adverse impact standard
because they are not practicable for
implementation in either the TMAA or
the GOA Study Area overall.
Second, in Chapter 5 (Mitigation) of
the 2020 GOA DSEIS/OEIS, the Navy
evaluated additional potential
procedural mitigation measures,
including increased mitigation zones,
ramp-up measures, additional passive
acoustic and visual monitoring, and
decreased vessel speeds. Some of these
measures have the potential to
incrementally reduce take to some
degree in certain circumstances, though
the degree to which this would occur is
typically low or uncertain. However, as
described in the Navy’s analysis, the
measures would have significant direct
negative effects on mission effectiveness
and are considered impracticable (see
Chapter 5, Mitigation, of 2020 GOA
DSEIS/OEIS). NMFS independently
reviewed the Navy’s evaluation and
concurs with this assessment, which
supports NMFS’ preliminary findings
that the impracticability of this
additional mitigation would greatly
outweigh any potential minor reduction
in marine mammal impacts that might
result; therefore, these additional
mitigation measures are not warranted.
Last, Chapter 5 (Mitigation) of the
2020 GOA DSEIS/OEIS, also describes a
comprehensive analysis of potential
geographic mitigation that includes
consideration of both a biological
assessment of how the potential time/
area limitation would benefit the
species and its habitat (e.g., is a key area
of biological importance or would result
in avoidance or reduction of impacts) in
the context of the stressors of concern in
the specific area and an operational
assessment of the practicability of
implementation (e.g., including an
assessment of the specific importance of
an area for training, considering
proximity to training ranges and
emergency landing fields and other
issues). In its second updated
application and the 2022 Supplement to
the 2020 GOA DSEIS/OEIS, the Navy
included an expansion to the mitigation
area previously referred to as the
Portlock Bank Mitigation Area, now
referred to as the Continental Shelf and
Slope Mitigation Area. The Navy has
found that geographic mitigation
beyond what is included in the 2020
GOA DSEIS/OEIS and 2022 Supplement
to the 2020 GOA DSEIS/OEIS is not
warranted because the anticipated
reduction of adverse impacts on marine
mammal species and their habitat is not
sufficient to offset the impracticability
of implementation. In some cases
potential benefits to marine mammals
were non-existent, while in others the
consequences on mission effectiveness
were too great.
NMFS has reviewed the Navy’s
analysis in Chapter 5 (Mitigation) of the
2020 GOA DSEIS/OEIS and Chapter 5
(Standard Operating Procedures,
Mitigation, and Monitoring) of the 2022
Supplement to the 2020 GOA DSEIS/
OEIS, which consider the same factors
that NMFS considers to satisfy the least
practicable adverse impact standard,
and concurs with the analysis and
conclusions. Therefore, NMFS is not
proposing to include any of the
measures that the Navy ruled out in the
2020 GOA DSEIS/OEIS. Below are the
mitigation measures that NMFS has
preliminarily determined would ensure
the least practicable adverse impact on
all affected species and their habitat,
including the specific considerations for
military readiness activities. The
following sections describe the
mitigation measures that would be
implemented in association with the
training activities analyzed in this
document. The mitigation measures are
organized into two categories:
procedural mitigation and mitigation
areas.
Procedural Mitigation
Procedural mitigation is mitigation
that the Navy would implement
whenever and wherever an applicable
training activity takes place within the
GOA Study Area. The Navy customizes
procedural mitigation for each
applicable activity category or stressor.
Procedural mitigation generally
involves: (1) the use of one or more
trained Lookouts to diligently observe
for specific biological resources
(including marine mammals) within a
mitigation zone, (2) requirements for
Lookouts to immediately communicate
sightings of specific biological resources
to the appropriate watch station for
information dissemination, and (3)
requirements for the watch station to
implement mitigation (e.g., halt an
activity) until certain recommencement
conditions have been met. The first
procedural mitigation (Table 31) is
designed to aid Lookouts and other
applicable Navy personnel with their
observation, environmental compliance,
and reporting responsibilities. The
remainder of the procedural mitigation
measures (Table 32 through Table 39)
are organized by stressor type and
activity category and include acoustic
stressors (i.e., active sonar, weapons
firing noise), explosive stressors (i.e.,
large-caliber projectiles, bombs), and
physical disturbance and strike stressors
(i.e., vessel movement, towed in-water
devices, small-, medium-, and largecaliber non-explosive practice
munitions, non-explosive bombs).
TABLE 31—PROCEDURAL MITIGATION FOR ENVIRONMENTAL AWARENESS AND EDUCATION
lotter on DSK11XQN23PROD with PROPOSALS2
Procedural mitigation description
Stressor or Activity:
• All training activities, as applicable.
Mitigation Requirements:
• Appropriate Navy personnel (including civilian personnel) involved in mitigation and training activity reporting under the specified activities
will complete one or more modules of the U.S. Navy Afloat Environmental Compliance Training Series, as identified in their career path
training plan. Modules include:
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00070
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
49725
TABLE 31—PROCEDURAL MITIGATION FOR ENVIRONMENTAL AWARENESS AND EDUCATION—Continued
Procedural mitigation description
—Introduction to the U.S. Navy Afloat Environmental Compliance Training Series. The introductory module provides information on environmental laws (e.g., Endangered Species Act, Marine Mammal Protection Act) and the corresponding responsibilities that are relevant to Navy training activities. The material explains why environmental compliance is important in supporting the Navy’s commitment to environmental stewardship.
—Marine Species Awareness Training. All bridge watch personnel, Commanding Officers, Executive Officers, maritime patrol aircraft
aircrews, anti-submarine warfare aircrews, Lookouts, and equivalent civilian personnel must successfully complete the Marine Species Awareness Training prior to standing watch or serving as a Lookout. The Marine Species Awareness Training provides information on sighting cues, visual observation tools and techniques, and sighting notification procedures. Navy biologists developed Marine Species Awareness Training to improve the effectiveness of visual observations for biological resources, focusing on marine
mammals and sea turtles, and including floating vegetation, jellyfish aggregations, and flocks of seabirds.
—U.S. Navy Protective Measures Assessment Protocol. This module provides the necessary instruction for accessing mitigation requirements during the event planning phase using the Protective Measures Assessment Protocol software tool.
—U.S. Navy Sonar Positional Reporting System and Marine Mammal Incident Reporting. This module provides instruction on the procedures and activity reporting requirements for the Sonar Positional Reporting System and marine mammal incident reporting.
Procedural Mitigation for Acoustic
Stressors
Mitigation measures for acoustic
stressors are provided in Table 32 and
Table 33.
TABLE 32—PROCEDURAL MITIGATION FOR ACTIVE SONAR
lotter on DSK11XQN23PROD with PROPOSALS2
Procedural mitigation description
Stressor or Activity:
• Mid-frequency active sonar and high-frequency active sonar:
—For vessel-based active sonar activities, mitigation applies only to sources that are positively controlled and deployed from manned
surface vessels (e.g., sonar sources towed from manned surface platforms).
—For aircraft-based active sonar activities, mitigation applies only to sources that are positively controlled and deployed from manned
aircraft that do not operate at high altitudes (e.g., rotary-wing aircraft). Mitigation does not apply to active sonar sources deployed
from unmanned aircraft or aircraft operating at high altitudes (e.g., maritime patrol aircraft).
Number of Lookouts and Observation Platform:
• Hull-mounted sources:
—1 Lookout: Platforms with space or manning restrictions while underway (at the forward part of a small boat or ship) and platforms
using active sonar while moored or at anchor.
—2 Lookouts: Platforms without space or manning restrictions while underway (at the forward part of the ship).
• Sources that are not hull-mounted:
—1 Lookout on the ship or aircraft conducting the activity.
Mitigation Requirements:
• Mitigation zones:
—1,000 yd (914.4 m) power down, 500 yd (457.2 m) power down, and 200 yd (182.9 m) shut down for hull-mounted mid-frequency active sonar (see During the activity below).
—200 yd (182.9 m) shut down for mid-frequency active sonar sources that are not hull-mounted, and high-frequency active sonar (see
During the activity below).
• Prior to the initial start of the activity (e.g., when maneuvering on station):
—Navy personnel will observe the mitigation zone for floating vegetation and marine mammals; if floating vegetation or a marine mammal is observed, Navy personnel will relocate or delay the start of active sonar transmission until the mitigation zone is clear of floating vegetation or the Commencement/recommencement conditions in this table are met for marine mammals.
• During the activity:
—Hull-mounted mid-frequency active sonar: Navy personnel will observe the mitigation zone for marine mammals; Navy personnel will
power down active sonar transmission by 6 dB if a marine mammal is observed within 1,000 yd (914.4 m) of the sonar source; Navy
personnel will power down active sonar transmission an additional 4 dB (10 dB total) if a marine mammal is observed within 500 yd
(457.2 m) of the sonar source; Navy personnel will cease transmission if a marine mammal is observed within 200 yd (182.9 m) of
the sonar source.
—Mid-frequency active sonar sources that are not hull-mounted, and high-frequency active sonar: Navy personnel will observe the mitigation zone for marine mammals; Navy personnel will cease transmission if a marine mammal is observed within 200 yd (182.9 m)
of the sonar source.
• Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel will allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying
the start) or during the activity (by not recommencing or powering up active sonar transmission) until one of the following conditions
has been met: (1) the animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone
based on a determination of its course, speed, and movement relative to the sonar source; (3) the mitigation zone has been clear
from any additional sightings for 10 minutes for aircraft-deployed sonar sources or 30 minutes for vessel-deployed sonar sources; (4)
for mobile activities, the active sonar source has transited a distance equal to double that of the mitigation zone size beyond the location of the last sighting; or (5) for activities using hull-mounted sonar, the Lookout concludes that dolphins are deliberately closing
in on the ship to ride the ship’s bow wave, and are therefore out of the main transmission axis of the sonar (and there are no other
marine mammal sightings within the mitigation zone).
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00071
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
49726
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
TABLE 33—PROCEDURAL MITIGATION FOR WEAPONS FIRING NOISE
Procedural mitigation description
Stressor or Activity:
• Weapon firing noise associated with large-caliber gunnery activities.
Number of Lookouts and Observation Platform:
• 1 Lookout positioned on the ship conducting the firing
—Depending on the activity, the Lookout could be the same one described in Procedural Mitigation for Explosive Large-Caliber Projectiles (Table 34) or Procedural Mitigation for Small-, Medium-, and Large-Caliber Non-Explosive Practice Munitions (Table 38).
Mitigation Requirements:
• Mitigation zone:
—30° on either side of the firing line out to 70 yd (64 m) from the muzzle of the weapon being fired.
• Prior to the initial start of the activity:
—Navy personnel will observe the mitigation zone for floating vegetation and marine mammals; if floating vegetation or a marine mammal is observed, Navy personnel will relocate or delay the start of weapon firing until the mitigation zone is clear of floating vegetation or the Commencement/recommencement conditions in this table are met for marine mammals.
• During the activity:
—Navy personnel will observe the mitigation zone for marine mammals; if a marine mammal is observed, Navy personnel will cease
weapon firing.
• Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel will allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying
the start) or during the activity (by not recommencing weapon firing) until one of the following conditions has been met: (1) the animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of
its course, speed, and movement relative to the firing ship; (3) the mitigation zone has been clear from any additional sightings for
30 minutes; or (4) for mobile activities, the firing ship has transited a distance equal to double that of the mitigation zone size beyond
the location of the last sighting.
Procedural Mitigation for Explosive
Stressors
Mitigation measures for explosive
stressors are provided in Table 34 and
Table 35.
TABLE 34—PROCEDURAL MITIGATION FOR EXPLOSIVE LARGE-CALIBER PROJECTILES
lotter on DSK11XQN23PROD with PROPOSALS2
Procedural mitigation description
Stressor or Activity:
• Gunnery activities using explosive large-caliber projectiles.
—Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
• 1 Lookout on the vessel or aircraft conducting the activity.
—Depending on the activity, the Lookout could be the same as the one described for Procedural Mitigation for Weapons Firing Noise
in Table 33.
• If additional platforms are participating in the activity, Navy personnel positioned in those assets (e.g., safety observers, evaluators) will
support observing the mitigation zone for marine mammals while performing their regular duties.
Mitigation Requirements:
• Mitigation zones:
—1,000 yd (914.4 m) around the intended impact location.
• Prior to the initial start of the activity (e.g., when maneuvering on station):
—Navy personnel will observe the mitigation zone for floating vegetation and marine mammals; if floating vegetation or a marine mammal is observed, Navy personnel will relocate or delay the start of firing until the mitigation zone is clear of floating vegetation or the
Commencement/recommencement conditions in this table are met for marine mammals.
• During the activity:
—Navy personnel will observe the mitigation zone for marine mammals; if a marine mammal is observed, Navy personnel will cease
firing.
• Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel will allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying
the start) or during the activity (by not recommencing firing) until one of the following conditions has been met: (1) the animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of its
course, speed, and movement relative to the intended impact location; (3) the mitigation zone has been clear from any additional
sightings for 30 minutes; or (4) for activities using mobile targets, the intended impact location has transited a distance equal to double that of the mitigation zone size beyond the location of the last sighting.
• After completion of the activity (e.g., prior to maneuvering off station):
—Navy personnel will, when practical (e.g., when platforms are not constrained by fuel restrictions or mission-essential follow-on commitments), observe the vicinity of where detonations occurred; if any injured or dead marine mammals are observed, Navy personnel
will follow established incident reporting procedures.
—If additional platforms are supporting this activity (e.g., providing range clearance), Navy personnel positioned on these assets will
assist in the visual observation of the area where detonations occurred.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00072
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
49727
TABLE 35—PROCEDURAL MITIGATION FOR EXPLOSIVE BOMBS
Procedural mitigation description
Stressor or Activity:
• Explosive bombs.
Number of Lookouts and Observation Platform:
• 1 Lookout positioned in the aircraft conducting the activity.
• If additional platforms are participating in the activity, Navy personnel positioned in those assets (e.g., safety observers, evaluators) will
support observing the mitigation zone for marine mammals while performing their regular duties.
Mitigation Requirements:
• Mitigation zone:
—2,500 yd (2,286 m) around the intended target.
• Prior to the initial start of the activity (e.g., when arriving on station):
—Navy personnel will observe the mitigation zone for floating vegetation and marine mammals; if floating vegetation or a marine mammal is observed, Navy personnel will relocate or delay the start of bomb deployment until the mitigation zone is clear of floating
vegetation or the Commencement/recommencement conditions in this table are met for marine mammals.
• During the activity (e.g., during target approach):
—Navy personnel will observe the mitigation zone for marine mammals; if a marine mammal is observed, Navy personnel will cease
bomb deployment.
• Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel will allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying
the start) or during the activity (by not recommencing bomb deployment) until one of the following conditions has been met: (1) the
animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination
of its course, speed, and movement relative to the intended target; (3) the mitigation zone has been clear from any additional
sightings for 10 minutes; or (4) for activities using mobile targets, the intended target has transited a distance equal to double that of
the mitigation zone size beyond the location of the last sighting.
• After completion of the activity (e.g., prior to maneuvering off station):
—Navy personnel will, when practical (e.g., when platforms are not constrained by fuel restrictions or mission-essential follow-on commitments), observe for marine mammals in the vicinity of where detonations occurred; if any injured or dead marine mammals are
observed, Navy personnel will follow established incident reporting procedures.
—If additional platforms are supporting this activity (e.g., providing range clearance), Navy personnel positioned on these assets will
assist in the visual observation of the area where detonations occurred.
Procedural Mitigation for Physical
Disturbance and Strike Stressors
Mitigation measures for physical
disturbance and strike stressors are
provided in Table 36 through Table 39.
TABLE 36—PROCEDURAL MITIGATION FOR VESSEL MOVEMENT
lotter on DSK11XQN23PROD with PROPOSALS2
Procedural Mitigation Description
Stressor or Activity:
• Vessel movement
—The mitigation will not be applied if (1) the vessel’s safety is threatened, (2) the vessel is restricted in its ability to maneuver (e.g.,
during launching and recovery of aircraft or landing craft, during towing activities, when mooring), (3) the vessel is submerged or operated autonomously, or (4) when impractical based on mission requirements (e.g., during Vessel Visit, Board, Search, and Seizure
activities as military personnel from ships or aircraft board suspect vessels).
Number of Lookouts and Observation Platform:
• 1 or more Lookouts on the underway vessel
• If additional watch personnel are positioned on underway vessels, those personnel (e.g., persons assisting with navigation or safety) will
support observing for marine mammals while performing their regular duties.
Mitigation Requirements:
• Mitigation zones:
—500 yd (457.2 m) around the vessel for whales.
—200 yd (182.9 m) around the vessel for marine mammals other than whales (except those intentionally swimming alongside or closing in to swim alongside vessels, such as bow-riding or wake-riding dolphins).
• When Underway:
—Navy personnel will observe the direct path of the vessel and waters surrounding the vessel for marine mammals.
—If a marine mammal is observed in the direct path of the vessel, Navy personnel will maneuver the vessel as necessary to maintain
the appropriate mitigation zone distance.
—If a marine mammal is observed within waters surrounding the vessel, Navy personnel will maintain situational awareness of that
animal’s position. Based on the animal’s course and speed relative to the vessel’s path, Navy personnel will maneuver the vessel as
necessary to ensure that the appropriate mitigation zone distance from the animal continues to be maintained.
• Additional requirements:
—If a marine mammal vessel strike occurs, Navy personnel will follow established incident reporting procedures.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00073
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
49728
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
TABLE 37—PROCEDURAL MITIGATION FOR TOWED IN-WATER DEVICES
Procedural mitigation description
Stressor or Activity:
• Towed in-water devices
—Mitigation applies to devices that are towed from a manned surface platform or manned aircraft, or when a manned support craft is
already participating in an activity involving in-water devices being towed by unmanned platforms.
—The mitigation will not be applied if the safety of the towing platform or in-water device is threatened.
Number of Lookouts and Observation Platform:
• 1 Lookout positioned on the towing platform or support craft.
Mitigation Requirements:
• Mitigation zones:
—250 yd (228.6 m) around the towed in-water device for marine mammals (except those intentionally swimming alongside or choosing
to swim alongside towing vessels, such as bow-riding or wake-riding dolphins)
• During the activity (i.e., when towing an in-water device)
—Navy personnel will observe the mitigation zone for marine mammals; if a marine mammal is observed, Navy personnel will maneuver to maintain distance.
TABLE 38—PROCEDURAL MITIGATION FOR SMALL-, MEDIUM-, AND LARGE-CALIBER NON-EXPLOSIVE PRACTICE MUNITIONS
Procedural mitigation description
Stressor or Activity:
• Gunnery activities using small-, medium-, and large-caliber non-explosive practice munitions
—Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
• 1 Lookout positioned on the platform conducting the activity.
—Depending on the activity, the Lookout could be the same as the one described in Procedural Mitigation for Weapons Firing Noise
(Table 33).
Mitigation Requirements:
• Mitigation zone:
—200 yd (182.9 m) around the intended impact location
• Prior to the initial start of the activity (e.g., when maneuvering on station):
—Navy personnel will observe the mitigation zone for floating vegetation and marine mammals; if floating vegetation or a marine mammal is observed, Navy personnel will relocate or delay the start of firing until the mitigation zone is clear of floating vegetation or the
Commencement/recommencement conditions in this table are met for marine mammals.
• During the activity:
—Navy personnel will observe the mitigation zone for marine mammals; if a marine mammal is observed, Navy personnel will cease
firing.
• Commencement/recommencement conditions after a marine mammal, sighting before or during the activity:
—Navy personnel will allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying
the start) or during the activity (by not recommencing firing) until one of the following conditions has been met: (1) the animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of its
course, speed, and movement relative to the intended impact location; (3) the mitigation zone has been clear from any additional
sightings for 10 minutes for aircraft-based firing or 30 minutes for vessel-based firing; or (4) for activities using a mobile target, the
intended impact location has transited a distance equal to double that of the mitigation zone size beyond the location of the last
sighting.
TABLE 39—PROCEDURAL MITIGATION FOR NON-EXPLOSIVE BOMBS
lotter on DSK11XQN23PROD with PROPOSALS2
Procedural mitigation description
Stressor or Activity:
• Non-explosive bombs.
Number of Lookouts and Observation Platform:
• 1 Lookout positioned in an aircraft.
Mitigation Requirements:
• Mitigation zone:
—1,000 yd (914.4 m) around the intended target.
• Prior to the initial start of the activity (e.g., when arriving on station):
—Navy personnel will observe the mitigation zone for floating vegetation and marine mammals; if floating vegetation or a marine mammal is observed, Navy personnel will relocate or delay the start of bomb deployment until the mitigation zone is clear of floating
vegetation or the Commencement/recommencement conditions in this table are met for marine mammals.
• During the activity (e.g., during approach of the target):
—Navy personnel will observe the mitigation zone for marine mammals; if a marine mammal is observed, Navy personnel will cease
bomb deployment.
• Commencement/recommencement conditions after a marine mammal sighting prior to or during the activity:
—Navy personnel will allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying
the start) or during the activity (by not recommencing bomb deployment) until one of the following conditions has been met: (1) the
animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination
of its course, speed, and movement relative to the intended target; (3) the mitigation zone has been clear from any additional
sightings for 10 minutes; or (4) for activities using mobile targets, the intended target has transited a distance equal to double that of
the mitigation zone size beyond the location of the last sighting.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00074
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
Mitigation Areas
In addition to procedural mitigation,
the Navy would implement mitigation
measures within mitigation areas to
avoid or minimize potential impacts on
marine mammals. The Navy took into
account the best available science and
the practicability of implementing
additional mitigation measures, and has
enhanced its mitigation measures
beyond those that were included in the
2017–2022 regulations to further reduce
impacts to marine mammals.
Information on the mitigation
measures that the Navy would
implement within mitigation areas is
provided in Table 40 (see below).
NMFS conducted an independent
analysis of the mitigation areas that the
Navy proposed, which are described
below. NMFS preliminarily concurs
with the Navy’s analysis, which
indicates that the measures in these
mitigation areas are both practicable and
would reduce the likelihood or severity
of adverse impacts to marine mammal
species or their habitat in the manner
described in the Navy’s analysis and
this rule. NMFS is heavily reliant on the
Navy’s description of operational
practicability, since the Navy is best
49729
equipped to describe the degree to
which a given mitigation measure
affects personnel safety or mission
effectiveness, and is practical to
implement. The Navy considers the
measures in this proposed rule to be
practicable, and NMFS concurs. We
further discuss the manner in which the
Geographic Mitigation Areas in the
proposed rule would reduce the
likelihood or severity of adverse impacts
to marine mammal species or their
habitat in the Preliminary Analysis and
Negligible Impact Determination
section.
TABLE 40—GEOGRAPHIC MITIGATION AREAS FOR MARINE MAMMALS IN THE GOA STUDY AREA
Mitigation area description
Stressor or Activity:
• Sonar.
• Explosives.
• Physical disturbance and strikes.
Mitigation Requirements: 1
• North Pacific Right Whale Mitigation Area.
—From June 1–September 30 within the North Pacific Right Whale Mitigation Area, Navy personnel will not use surface ship hullmounted MF1 mid-frequency active sonar during training.
• Continental Shelf and Slope Mitigation Area.
—Navy personnel will not detonate explosives below 10,000 ft. altitude (including at the water surface) in the Continental Shelf and
Slope Mitigation Area during training.
• Pre-event Awareness Notifications in the Temporary Maritime Activities Area.
—The Navy will issue pre-event awareness messages to alert vessels and aircraft participating in training activities within the TMAA to
the possible presence of concentrations of large whales on the continental shelf and slope. Occurrences of large whales may be
higher over the continental shelf and slope relative to other areas of the TMAA. Large whale species in the TMAA include, but are
not limited to, fin whale, blue whale, humpback whale, gray whale, North Pacific right whale, sei whale, and sperm whale. To maintain safety of navigation and to avoid interactions with marine mammals, the Navy will instruct personnel to remain vigilant to the
presence of large whales that may be vulnerable to vessel strikes or potential impacts from training activities. Additionally, Navy personnel will use the information from the awareness notification messages to assist their visual observation of applicable mitigation
zones during training activities and to aid in the implementation of procedural mitigation.
1 Should national security present a requirement to conduct training prohibited by the mitigation requirements specified in this table, naval units
will obtain permission from the designated Command, U.S. Third Fleet Command Authority, prior to commencement of the activity. The Navy will
provide NMFS with advance notification and include relevant information about the event (e.g., sonar hours, use of explosives detonated below
10,000 ft altitude (including at the water surface) in its annual activity reports to NMFS.
lotter on DSK11XQN23PROD with PROPOSALS2
BILLING CODE 3510–22–P
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00075
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
BILLING CODE 3510–22–C
North Pacific Right Whale Mitigation
Area
Mitigation within the North Pacific
Right Whale Mitigation Area is
primarily designed to avoid or further
reduce potential impacts to North
Pacific right whales within important
feeding habitat. The mitigation area
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
fully encompasses the portion of the
BIA identified by Ferguson et al. (2015)
for North Pacific right whale feeding
that overlaps the GOA Study Area
(overlap between the GOA Study Area
and the BIA occurs in the TMAA only)
(Figure 2). North Pacific right whales are
thought to occur in the highest densities
in the BIA from June to September. The
Navy would not use surface ship hull-
PO 00000
Frm 00076
Fmt 4701
Sfmt 4702
mounted MF1 mid-frequency active
sonar in the mitigation area from June
1 to September 30, as was also required
in the Phase II (2017–2022) rule. The
North Pacific Right Whale Mitigation
Area is fully within the boundary of the
Continental Shelf and Slope Mitigation
Area, discussed below. Therefore, the
mitigation requirements in that area also
apply to the North Pacific Right Whale
E:\FR\FM\11AUP2.SGM
11AUP2
EP11AU22.004</GPH>
49730
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
Mitigation Area. While the potential
occurrence of North Pacific right whales
in the GOA Study Area is expected to
be rare due to the species’ extremely
low population, these mitigation
requirements would help further avoid
or further reduce the potential for
impacts to occur within North Pacific
right whale feeding habitat, thus likely
reducing the number of takes of North
Pacific right whales, as well as the
severity of any disturbances by reducing
the likelihood that feeding is
interrupted, delayed, or precluded for
some limited amount of time.
Additionally, the North Pacific Right
Whale Mitigation Area overlaps with a
small portion of the humpback whale
critical habitat Unit 5, in the southwest
corner of the TMAA. While the overlap
of the two areas is limited, mitigation in
the North Pacific Right Whale
Mitigation Area may reduce the number
and/or severity of takes of humpback
whales in this important area.
The mitigation in this area would also
help avoid or reduce potential impacts
on fish and invertebrates that inhabit
the mitigation area and which marine
mammals prey upon. As described in
Section 5.4.1.5 (Fisheries Habitats) of
the 2020 GOA DSEIS/OEIS, the
productive waters off Kodiak Island
support a strong trophic system from
plankton, invertebrates, small fish, and
higher-level predators, including large
fish and marine mammals.
Continental Shelf and Slope Mitigation
Area
The Continental Shelf and Slope
Mitigation Area encompasses the
portion of the continental shelf and
slope that overlaps the TMAA (the
entire continental shelf and slope out to
the 4,000 m depth contour; Figure 2).
The Navy would not detonate
explosives below 10,000 ft. altitude
(including at the water surface) in the
Continental Shelf and Slope Mitigation
Area during training. (As stated
previously, the Navy does not plan to
use in-water explosives anywhere in the
GOA Study Area.) Mitigation in the
Continental Shelf and Slope Mitigation
Area was initially designed to avoid or
reduce potential impacts on fishery
resources for Alaska Natives. However,
the area includes highly productive
waters where marine mammals,
including humpback whales (Lagerquist
et al. 2008) and North Pacific right
whales, feed, and overlaps with a small
portion of the North Pacific right whale
feeding BIA off of Kodiak Island.
Additionally, the Continental Shelf and
Slope Mitigation Area overlaps with a
very small portion of the humpback
whale critical habitat Unit 5, on the
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
western side of the TMAA, and a small
portion of humpback whale critical
habitat Unit 8 on the north side of the
TMAA. The Continental Shelf and
Slope mitigation area also overlaps with
a very small portion of the gray whale
migration BIA. The remainder of the
designated critical habitat and BIAs are
located beyond the boundaries of the
GOA Study Area. While the overlap of
the mitigation area with critical habitat
and feeding and migratory BIAs is
limited, mitigation in the Continental
Shelf and Slope Mitigation Area may
reduce the probability, number, and/or
severity of takes of humpback whales,
North Pacific right whales, and gray
whales in this important area (noting
that no takes are predicted for gray
whales). Additionally, mitigation in this
area will likely reduce the number and
severity of potential impacts to marine
mammals in general, by reducing the
likelihood that feeding is interrupted,
delayed, or precluded for some limited
amount of time.
Pre-Event Awareness Notifications in
the Temporary Maritime Activities Area
The Navy will issue awareness
messages prior to the start of TMAA
training activities to alert vessels and
aircraft operating within the TMAA to
the possible presence of concentrations
of large whales, including but not
limited to, fin whale, blue whale,
humpback whale, gray whales, North
Pacific right whale, sei whale, minke
whale, and sperm whale, especially
when traversing on the continental shelf
and slope where densities of these
species may be higher. To maintain
safety of navigation and to avoid
interactions with marine mammals, the
Navy will instruct vessels to remain
vigilant to the presence of large whales
that may be vulnerable to vessel strikes
or potential impacts from training
activities. Navy personnel will use the
information from the awareness
notification messages to assist their
visual observation of applicable
mitigation zones during training
activities and to aid in the
implementation of procedural
mitigation.
This mitigation would help avoid or
further reduce any potential impacts
from vessel strikes and training
activities on large whales within the
TMAA.
Availability for Subsistence Uses
The nature of subsistence activities by
Alaska Natives in the GOA Study Area
are discussed below, in the Subsistence
Harvest of Marine Mammals section of
this proposed rule.
PO 00000
Frm 00077
Fmt 4701
Sfmt 4702
49731
Mitigation Conclusions
NMFS has carefully evaluated the
Navy’s proposed mitigation measures—
many of which were developed with
NMFS’ input during the previous
phases of Navy training authorizations
but several of which are new since
implementation of the 2017 to 2022
regulations—and considered a broad
range of other measures (i.e., the
measures considered but eliminated in
the 2020 GOA DSEIS/OEIS, which
reflect many of the comments that have
arisen from public input or through
discussion with NMFS in past years) in
the context of ensuring that NMFS
prescribes the means of effecting the
least practicable adverse impact on the
affected marine mammal species and
their habitat. Our evaluation of potential
measures included consideration of the
following factors in relation to one
another: the manner in which, and the
degree to which, the successful
implementation of the mitigation
measures is expected to reduce the
likelihood and/or magnitude of adverse
impacts to marine mammal species and
their habitat; the proven or likely
efficacy of the measures; and the
practicability of the measures for
applicant implementation, including
consideration of personnel safety,
practicality of implementation, and
impact on the effectiveness of the
military readiness activity.
Based on our evaluation of the Navy’s
proposed measures, as well as other
measures considered by the Navy and
NMFS, NMFS has preliminarily
determined that these proposed
mitigation measures are appropriate
means of effecting the least practicable
adverse impact on marine mammal
species and their habitat, paying
particular attention to rookeries, mating
grounds, and areas of similar
significance, and considering
specifically personnel safety,
practicality of implementation, and
impact on the effectiveness of the
military readiness activity.
Additionally, an adaptive management
component helps further ensure that
mitigation is regularly assessed and
provides a mechanism to improve the
mitigation, based on the factors above,
through modification as appropriate.
The proposed rule comment period
provides the public an opportunity to
submit recommendations, views, and/or
concerns regarding the Navy’s activities
and the proposed mitigation measures.
While NMFS has preliminarily
determined that the Navy’s proposed
mitigation measures would effect the
least practicable adverse impact on the
affected species and their habitat, NMFS
E:\FR\FM\11AUP2.SGM
11AUP2
49732
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
will consider all public comments to
help inform our final determination.
Consequently, the proposed mitigation
measures may be refined, modified,
removed, or added to prior to the
issuance of the final rule based on
public comments received and, as
appropriate, analysis of additional
potential mitigation measures.
Proposed Monitoring
Section 101(a)(5)(A) of the MMPA
states that in order to authorize
incidental take for an activity, NMFS
must set forth requirements pertaining
to the monitoring and reporting of such
taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13)
indicate that requests for incidental take
authorizations must include the
suggested means of accomplishing the
necessary monitoring and reporting that
will result in increased knowledge of
the species and of the level of taking or
impacts on populations of marine
mammals that are expected to be
present.
Although the Navy has been
conducting research and monitoring for
over 20 years in areas where it has been
training, it developed a formal marine
species monitoring program in support
of the GOA Study Area MMPA and ESA
processes in 2009. Across all Navy
training and testing study areas, the
robust marine species monitoring
program has resulted in hundreds of
technical reports and publications on
marine mammals that have informed
Navy and NMFS analyses in
environmental planning documents,
rules, and Biological Opinions. The
reports are made available to the public
on the Navy’s marine species
monitoring website
(www.navymarinespeciesmonitoring.us)
and the data on the Ocean
Biogeographic Information System
Spatial Ecological Analysis of
Megavertebrate Populations (OBIS–
SEAMAP) (https://seamap.env.
duke.edu/).
The Navy would continue collecting
monitoring data to inform our
understanding of the occurrence of
marine mammals in the GOA Study
Area; the likely exposure of marine
mammals to stressors of concern in the
GOA Study Area; the response of
marine mammals to exposures to
stressors; the consequences of a
particular marine mammal response to
their individual fitness and, ultimately,
populations; and the effectiveness of
implemented mitigation measures.
Taken together, mitigation and
monitoring comprise the Navy’s
integrated approach for reducing
environmental impacts from the
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
specified activities. The Navy’s overall
monitoring approach seeks to leverage
and build on existing research efforts
whenever possible.
As agreed upon between the Navy and
NMFS, the monitoring measures
presented here, as well as the mitigation
measures described above, focus on the
protection and management of
potentially affected marine mammals. A
well-designed monitoring program can
provide important feedback for
validating assumptions made in
analyses and allow for adaptive
management of marine resources.
Monitoring is required under the
MMPA, and details of the monitoring
program for the specified activities have
been developed through coordination
between NMFS and the Navy through
the regulatory process for previous Navy
at-sea training and testing activities.
Integrated Comprehensive Monitoring
Program
The Navy’s Integrated Comprehensive
Monitoring Program (ICMP) is intended
to coordinate marine species monitoring
efforts across all regions and to allocate
the most appropriate level and type of
effort for each range complex based on
a set of standardized objectives, and in
acknowledgement of regional expertise
and resource availability. The ICMP is
designed to be flexible, scalable, and
adaptable through the adaptive
management and strategic planning
processes to periodically assess progress
and reevaluate objectives. This process
includes conducting an annual adaptive
management review meeting, at which
the Navy and NMFS jointly consider the
prior-year goals, monitoring results, and
related scientific advances to determine
if monitoring plan modifications are
warranted to more effectively address
program goals. Although the ICMP does
not specify actual monitoring field work
or individual projects, it does establish
a matrix of goals and objectives that
have been developed in coordination
with NMFS. As the ICMP is
implemented through the Strategic
Planning Process, detailed and specific
studies will be developed which
support the Navy’s and NMFS top-level
monitoring goals. In essence, the ICMP
directs that monitoring activities
relating to the effects of Navy training
and testing activities on marine species
should be designed to contribute
towards or accomplish one or more of
the following top-level goals:
• An increase in the understanding of
the likely occurrence of marine
mammals and ESA-listed marine
species in the vicinity of the action (i.e.,
presence, abundance, distribution, and
density of species);
PO 00000
Frm 00078
Fmt 4701
Sfmt 4702
• An increase in the understanding of
the nature, scope, or context of the
likely exposure of marine mammals and
ESA-listed species to any of the
potential stressors associated with the
action (e.g., sound, explosive
detonation, or expended materials),
through better understanding of one or
more of the following: (1) the nature of
the action and its surrounding
environment (e.g., sound-source
characterization, propagation, and
ambient noise levels), (2) the affected
species (e.g., life history or dive
patterns), (3) the likely co-occurrence of
marine mammals and ESA-listed marine
species with the action (in whole or
part), and (4) the likely biological or
behavioral context of exposure to the
stressor for the marine mammal and
ESA-listed marine species (e.g., age
class of exposed animals or known
pupping, calving, or feeding areas);
• An increase in the understanding of
how individual marine mammals or
ESA-listed marine species respond
(behaviorally or physiologically) to the
specific stressors associated with the
action (in specific contexts, where
possible, e.g., at what distance or
received level);
• An increase in the understanding of
how anticipated individual responses,
to individual stressors or anticipated
combinations of stressors, may impact
either (1) the long-term fitness and
survival of an individual; or (2) the
population, species, or stock (e.g.,
through impacts on annual rates of
recruitment or survival);
• An increase in the understanding of
the effectiveness of mitigation and
monitoring measures;
• A better understanding and record
of the manner in which the Navy
complies with the incidental take
regulations and LOAs and the ESA
Incidental Take Statement;
• An increase in the probability of
detecting marine mammals (through
improved technology or methods), both
specifically within the mitigation zone
(thus allowing for more effective
implementation of the mitigation) and
in general, to better achieve the above
goals; and
• Ensuring that adverse impacts of
activities remain at the least practicable
level.
Strategic Planning Process for Marine
Species Monitoring
The Navy also developed the Strategic
Planning Process for Marine Species
Monitoring, which serves to guide the
investment of resources to most
efficiently address ICMP objectives and
intermediate scientific objectives
developed through this process. The
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
Strategic Planning Process establishes
the guidelines and processes necessary
to develop, evaluate, and fund
individual projects based on objective
scientific study questions. The process
uses an underlying framework designed
around intermediate scientific
objectives and a conceptual framework
incorporating a progression of
knowledge spanning occurrence,
exposure, response, and consequence.
The Strategic Planning Process for
Marine Species Monitoring is used to
set overarching intermediate scientific
objectives; develop individual
monitoring project concepts; evaluate,
prioritize, and select specific monitoring
projects to fund or continue supporting
for a given fiscal year; execute and
manage selected monitoring projects;
and report and evaluate progress and
results. This process addresses relative
investments to different range
complexes based on goals across all
range complexes, and monitoring
would leverage multiple techniques
for data acquisition and
analysis whenever possible. More
information on the Strategic Planning
Process for Marine Species Monitoring
including results, reports, and
publications, is also available online
(https://www.navymarinespecies
monitoring.us/).
Past and Current Monitoring in the GOA
Study Area
The monitoring program has
undergone significant changes since the
first rule was issued for the TMAA in
2011, which highlights the monitoring
program’s evolution through the process
of adaptive management. The
monitoring program developed for the
first cycle of environmental compliance
documents (e.g., U.S. Department of the
Navy, 2008a, 2008b) utilized effortbased compliance metrics that were
somewhat limiting. Through adaptive
management discussions, the Navy
designed and conducted monitoring
studies according to scientific objectives
and eliminated specific effort
requirements.
Progress has also been made on the
conceptual framework categories from
the Scientific Advisory Group for Navy
Marine Species Monitoring (U.S.
Department of the Navy, 2011), ranging
from occurrence of animals, to their
exposure, response, and population
consequences. The Navy continues to
manage the Atlantic and Pacific
program as a whole, including what is
now the GOA Study Area, with
monitoring in each range complex
taking a slightly different but
complementary approach. The Navy has
continued to use the approach of
VerDate Sep<11>2014
18:47 Aug 10, 2022
Jkt 256001
layering multiple simultaneous
components in many of the range
complexes to leverage an increase in
return of the progress toward answering
scientific monitoring questions. This
includes in the TMAA, for example (a)
Passive Acoustic Monitoring for Marine
Mammals in the Gulf of Alaska
Temporary Maritime Activities Area
May to September 2015 and April to
September 2017 (Rice et al., 2018b); (b)
analysis of existing passive acoustic
monitoring datasets; and (c) Passive
Acoustic Monitoring of Marine
Mammals Using Gliders (Klinck et al.,
2016).
Numerous publications, dissertations,
and conference presentations have
resulted from research conducted under
the marine species monitoring program,
including research conducted in what is
now the GOA Study Area (https://
www.navymarinespeciesmonitoring.us/
reading-room/publications/), leading to
a significant contribution to the body of
marine mammal science. Publications
on occurrence, distribution, and density
have fed the modeling input, and
publications on exposure and response
have informed Navy and NMFS analysis
of behavioral response and
consideration of mitigation measures.
Furthermore, collaboration between
the monitoring program and the Navy’s
research and development (e.g., the
Office of Naval Research) and
demonstration-validation (e.g., Living
Marine Resources) programs has been
strengthened, leading to research tools
and products that have already
transitioned to the monitoring program.
These include Marine Mammal
Monitoring on Ranges, controlled
exposure experiment behavioral
response studies, acoustic sea glider
surveys, and global positioning systemenabled satellite tags. Recent progress
has been made with better integration
with monitoring across all Navy at-sea
study areas, including the AFTT Study
Area in the Atlantic Ocean, and various
other ranges. Publications from the
Living Marine Resources and Office of
Naval Research programs have also
resulted in significant contributions to
hearing, acoustic criteria used in effects
modeling, exposure, and response, as
well as in developing tools to assess
biological significance (e.g.,
consequences).
NMFS and the Navy also consider
data collected during procedural
mitigations as monitoring. Data are
collected by shipboard personnel on
hours spent training, hours of
observation, hours of sonar, and marine
mammals observed within the
mitigation zones when mitigations are
implemented. These data are provided
PO 00000
Frm 00079
Fmt 4701
Sfmt 4702
49733
to NMFS in both classified and
unclassified annual training reports,
which would continue under this
proposed rule.
NMFS has received multiple years’
worth of annual training and monitoring
reports addressing active sonar use and
explosive detonations within the TMAA
and other Navy range complexes. The
data and information contained in these
reports have been considered in
developing mitigation and monitoring
measures for the proposed training
activities within the GOA Study Area.
The Navy’s annual training and
monitoring reports may be viewed at:
https://www.navymarinespecies
monitoring.us/reporting/.
The Navy’s marine species monitoring
program supports monitoring projects in
the GOA Study Area. Additional details
on the scientific objectives for each
project can be found at https://
www.navymarinespeciesmonitoring.us/
regions/pacific/current-projects/.
Projects can be either major multi-year
efforts, or one to 2-year special studies.
The emphasis on monitoring in the
GOA Study Area is directed towards
collecting and analyzing passive
acoustic monitoring and telemetry data
for marine mammals and salmonids.
Specific monitoring under the
previous regulations (which covered
only the TMAA) included:
• The continuation of the Navy’s
collaboration with NOAA on the Pacific
Marine Assessment Program for
Protected Species (PacMAPPS) survey.
A systematic line transect survey in the
Gulf of Alaska was completed in 2021.
A second PacMAPPS survey is planned
for the Gulf of Alaska in 2023. These
surveys will increase knowledge of
marine mammal occurrence, density,
and population identity in the TMAA.
• A Characterizing the Distribution of
ESA-Listed Salmonids in Washington
and Alaska study. The goal of this study
is to use a combination of acoustic and
pop-up satellite tagging technology to
provide critical information on spatial
and temporal distribution of salmonids
to inform salmon management, U.S.
Navy training activities, and Southern
Resident killer whale conservation. The
study seeks to (1) determine the
occurrence and timing of salmonids
within the Navy training ranges; (2)
describe the influence of environmental
covariates on salmonid occurrence; and
(3) describe the occurrence of salmonids
in relation to Southern Resident killer
whale distribution. Methods include
acoustic telemetry (pinger tags) and
pop-up satellite tagging.
• A Telemetry and Genetic Identity of
Chinook Salmon in Alaska study. The
goal of this study is to provide critical
E:\FR\FM\11AUP2.SGM
11AUP2
49734
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
information on the spatial and temporal
distribution of Chinook salmon and to
utilize genetic analysis techniques to
inform salmon management. Tagging is
occurring at several sites within the Gulf
of Alaska.
• A North Pacific Humpback Whale
Tagging study. This project combines
tagging, biopsy sampling, and photoidentification efforts along the United
States west coast and Hawaii to examine
movement patterns and whale use of
Navy training and testing areas and
NMFS-identified BIAs, examine
migration routes, and analyze dive
behavior and ecological relationships
between whale locations and
oceanographic conditions (Mate et al.,
2017; Irvine et al., 2020).
Future monitoring efforts in the GOA
Study Area are anticipated to continue
along the same objectives: determining
the species and populations of marine
mammals present and potentially
exposed to Navy training activities in
the GOA Study Area, through tagging,
passive acoustic monitoring, refined
modeling, photo identification, biopsies,
and visual monitoring, as well as
characterizing spatial and temporal
distribution of salmonids, including
Chinook salmon.
Adaptive Management
The proposed regulations governing
the take of marine mammals incidental
to Navy training activities in the GOA
Study Area contain an adaptive
management component. Our
understanding of the effects of Navy
training activities (e.g., acoustic and
explosive stressors) on marine mammals
continues to evolve, which makes the
inclusion of an adaptive management
component both valuable and necessary
within the context of 7-year regulations.
The reporting requirements associated
with this rule are designed to provide
NMFS with monitoring data from the
previous year to allow NMFS to
consider whether any changes to
existing mitigation and monitoring
requirements are appropriate. The use of
adaptive management allows NMFS to
consider new information from different
sources to determine (with input from
the Navy regarding practicability) on an
annual or biennial basis if mitigation or
monitoring measures should be
modified (including additions or
deletions). Mitigation measures could be
modified if new data suggests that such
modifications would have a reasonable
likelihood of more effectively
accomplishing the goals of the
mitigation and monitoring and if the
measures are practicable. If the
modifications to the mitigation,
monitoring, or reporting measures are
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
substantial, NMFS would publish a
notice of the planned LOA in the
Federal Register and solicit public
comment.
The following are some of the
possible sources of applicable data to be
considered through the adaptive
management process: (1) results from
monitoring and exercise reports, as
required by MMPA authorizations; (2)
compiled results of Navy funded
research and development studies; (3)
results from specific stranding
investigations; (4) results from general
marine mammal and sound research;
and (5) any information which reveals
that marine mammals may have been
taken in a manner, extent, or number
not authorized by these regulations or
subsequent LOA. The results from
monitoring reports and other studies
may be viewed at https://
www.navymarinespeciesmonitoring.us.
Proposed Reporting
In order to issue incidental take
authorization for an activity, section
101(a)(5)(A) of the MMPA states that
NMFS must set forth requirements
pertaining to the monitoring and
reporting of such taking. Effective
reporting is critical both to compliance
as well as ensuring that the most value
is obtained from the required
monitoring. Reports from individual
monitoring events, results of analyses,
publications, and periodic progress
reports for specific monitoring projects
would be posted to the Navy’s Marine
Species Monitoring web portal: https://
www.navymarinespeciesmonitoring.us.
There are several different reporting
requirements pursuant to the 2017–2022
regulations. All of these reporting
requirements would be continued under
this proposed rule for the 7-year period;
however, the reporting schedule for the
GOA Annual Training Report would be
slightly changed to align the reporting
schedule with the activity period (see
the GOA Annual Training Report
section, below).
Notification of Injured, Live Stranded,
or Dead Marine Mammals
The Navy would consult the
Notification and Reporting Plan, which
sets out notification, reporting, and
other requirements when injured, live
stranded, or dead marine mammals are
detected. The Notification and
Reporting Plan is available for review at
https://www.fisheries.noaa.gov/
national/marine-mammal-protection/
incidental-take-authorizations-militaryreadiness-activities.
PO 00000
Frm 00080
Fmt 4701
Sfmt 4702
Annual GOA Marine Species Monitoring
Report
The Navy would submit an annual
report to NMFS of the GOA Study Area
monitoring, which would be included
in a Pacific-wide monitoring report and
include results specific to the GOA
Study Area, describing the
implementation and results of
monitoring from the previous calendar
year. Data collection methods would be
standardized across Pacific Range
Complexes including the MITT, HSTT,
NWTT, and GOA Study Areas to the
best extent practicable, to allow for
comparison among different geographic
locations. The report would be
submitted to the Director, Office of
Protected Resources, NMFS, either
within 3 months after the end of the
calendar year, or within 3 months after
the conclusion of the monitoring year,
to be determined by the Adaptive
Management process. NMFS would
submit comments or questions on the
draft monitoring report, if any, within 3
months of receipt. The report would be
considered final after the Navy has
addressed NMFS’ comments, or 3
months after submittal if NMFS does
not provide comments on the report.
The report would describe progress of
knowledge made with respect to
monitoring study questions across
multiple Navy ranges associated with
the ICMP. Similar study questions
would be treated together so that
progress on each topic is summarized
across all Navy ranges. The report need
not include analyses and content that
does not provide direct assessment of
cumulative progress on the monitoring
plan study questions. This would allow
the Navy to provide a cohesive
monitoring report covering multiple
ranges (as per ICMP goals), rather than
entirely separate reports for the MITT,
HSTT, NWTT, and GOA Study Areas.
GOA Annual Training Report
Each year in which training activities
are conducted in the GOA Study Area,
the Navy would submit one preliminary
report (Quick Look Report) to NMFS
detailing the status of applicable sound
sources within 21 days after the
completion of the training activities in
the GOA Study Area. Each year in
which activities are conducted, the
Navy would also submit a detailed
report (GOA Annual Training Report) to
NMFS within 3 months after completion
of the training activities. The Phase II
rule required the Navy to submit the
GOA Annual Training Report within 3
months after the anniversary of the date
of issuance of the LOA. NMFS would
submit comments or questions on the
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
report, if any, within one month of
receipt. The report would be considered
final after the Navy has addressed
NMFS’ comments, or one month after
submittal if NMFS does not provide
comments on the report. The annual
reports would contain information
about the MTE, (exercise designator,
date that the exercise began and ended,
location, number and types of active
and passive sonar sources used in the
exercise, number and types of vessels
and aircraft that participated in the
exercise, etc.), individual marine
mammal sighting information for each
sighting in each exercise where
mitigation was implemented, a
mitigation effectiveness evaluation, and
a summary of all sound sources used
(total hours or quantity of each bin of
sonar or other non-impulsive source;
total annual number of each type of
explosive(s); and total annual
expended/detonated rounds (bombs and
large-caliber projectiles) for each
explosive bin).
The annual report (which, as stated
above, would only be required during
years in which activities are conducted)
would also contain cumulative sonar
and explosive use quantity from
previous years’ reports through the
current year. Additionally, if there were
any changes to the sound source
allowance in the reporting year, or
cumulatively, the report would include
a discussion of why the change was
made and include analysis to support
how the change did or did not affect the
analysis in the GOA SEIS/OEIS and
MMPA final rule. The analysis in the
detailed report would be based on the
accumulation of data from the current
year’s report and data collected from
previous annual reports. The final
annual/close-out report at the
conclusion of the authorization period
(year seven) would also serve as the
comprehensive close-out report and
include both the final year annual use
compared to annual authorization as
well as a cumulative 7-year annual use
compared to 7-year authorization. This
report would also note any years in
which training did not occur. NMFS
must submit comments on the draft
close-out report, if any, within 3 months
of receipt. The report would be
considered final after the Navy has
addressed NMFS’ comments, or 3
months after the submittal of the draft
if NMFS does not provide comments.
Information included in the annual
reports may be used to inform future
adaptive management of activities
within the GOA Study Area. See the
regulations below for more detail on the
content of the annual report.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
Other Reporting and Coordination
The Navy would continue to report
and coordinate with NMFS for the
following:
• Annual marine species monitoring
technical review meetings that also
include researchers and the Marine
Mammal Commission; and
• Annual Adaptive Management
meetings that also include the Marine
Mammal Commission (and occur in
conjunction with the annual marine
species monitoring technical review
meetings).
Preliminary Analysis and Negligible
Impact Determination
General Negligible Impact Analysis
Introduction
NMFS has defined negligible impact
as an impact resulting from the
specified activity that cannot be
reasonably expected to, and is not
reasonably likely to, adversely affect the
species or stock through effects on
annual rates of recruitment or survival
(50 CFR 216.103). A negligible impact
finding is based on the lack of likely
adverse effects on annual rates of
recruitment or survival (i.e., populationlevel effects). An estimate of the number
of takes alone is not enough information
on which to base an impact
determination. For Level A harassment
or Level B harassment (as presented in
Table 30), in addition to considering
estimates of the number of marine
mammals that might be taken NMFS
considers other factors, such as the
likely nature of any responses (e.g.,
intensity, duration) and the context of
any responses (e.g., critical reproductive
time or location, migration), as well as
effects on habitat and the likely
effectiveness of the mitigation. We also
assess the number, intensity, and
context of estimated takes by evaluating
this information relative to population
status. Consistent with the 1989
preamble for NMFS’ implementing
regulations (54 FR 40338; September 29,
1989), the impacts from other past and
ongoing anthropogenic activities are
incorporated into this analysis via their
impacts on the environmental baseline
(e.g., as reflected in the regulatory status
of the species, population size and
growth rate where known, other ongoing
sources of human-caused mortality, and
ambient noise levels).
In the Estimated Take of Marine
Mammals section, we identified the
subset of potential effects that would be
expected to rise to the level of takes
both annually and over the 7-year
period covered by this proposed rule,
and then identified the maximum
PO 00000
Frm 00081
Fmt 4701
Sfmt 4702
49735
number of harassment takes that are
reasonably expected to occur based on
the methods described. The impact that
any given take would have is dependent
on many case-specific factors that need
to be considered in the negligible
impact analysis (e.g., the context of
behavioral exposures such as duration
or intensity of a disturbance, the health
of impacted animals, the status of a
species that incurs fitness-level impacts
to individuals, etc.). For this proposed
rule we evaluated the likely impacts of
the enumerated maximum number of
harassment takes that are proposed for
authorization and reasonably expected
to occur, in the context of the specific
circumstances surrounding these
predicted takes. Last, we collectively
evaluated this information, as well as
other more taxa-specific information
and mitigation measure effectiveness, in
group-specific assessments that support
our negligible impact conclusions for
each stock or species. Because all of the
Navy’s specified activities would occur
within the ranges of the marine mammal
stocks identified in the rule, all
negligible impact analyses and
determinations are at the stock level
(i.e., additional species-level
determinations are not needed).
As explained in the Estimated Take of
Marine Mammals section, no take by
serious injury or mortality is authorized
or anticipated to occur. There have been
no recorded Navy vessel strikes of any
marine mammals during training in the
GOA Study Area to date, nor were
incidental takes by injury or mortality
resulting from vessel strike predicted in
the Navy’s analysis. For these and the
other reasons described in the Potential
Effects of Vessel Strike section, NMFS
concurs that vessel strike is not likely to
occur during the 21-day GOA Study
Area training activities, and therefore is
not proposing authorization in this rule.
The specified activities reflect
representative levels of training
activities. The Description of the
Specified Activity section describes
annual activities. There may be some
flexibility in the exact number of hours,
items, or detonations that may vary from
year to year, but take totals would not
exceed the maximum annual totals and
7-year totals indicated in Table 30.
(Further, as noted previously, the GOA
Study Area training activities would not
occur continuously throughout the year,
but rather, for a maximum of 21 days
once annually between April and
October.) We base our analysis and
negligible impact determination on the
maximum number of takes that would
be reasonably expected to occur
annually and are proposed to be
authorized, although, as stated before,
E:\FR\FM\11AUP2.SGM
11AUP2
49736
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
the number of takes is only a part of the
analysis, which includes extensive
qualitative consideration of other
contextual factors that influence the
degree of impact of the takes on the
affected individuals. To avoid
repetition, we provide some general
analysis immediately below that applies
to all the species listed in Table 30,
given that some of the anticipated
effects of the Navy’s training activities
on marine mammals are expected to be
relatively similar in nature. However,
below that, we break our analysis into
species (and/or stocks), or groups of
species (and the associated stocks)
where relevant similarities exist, to
provide more specific information
related to the anticipated effects on
individuals of a specific stock or where
there is information about the status or
structure of any species or stock that
would lead to a differing assessment of
the effects on the species or stock.
Organizing our analysis by grouping
species or stocks that share common
traits or that would respond similarly to
effects of the Navy’s activities and then
providing species- or stock-specific
information allows us to avoid
duplication while assuring that we have
analyzed the effects of the specified
activities on each affected species or
stock.
Harassment
The Navy’s harassment take request is
based on a model and quantitative
assessment of mitigation, which NMFS
reviewed and concurs appropriately
predicts the maximum amount of
harassment that is reasonably likely to
occur, with the exception of the Eastern
North Pacific stock of gray whale, and
the Western North Pacific stock of
humpback whale, for which NMFS has
proposed authorizing 4 and 3 Level B
harassment takes annually, respectively,
as described in the Estimated Take of
Marine Mammals section. The model
calculates sound energy propagation
from sonar, other active acoustic
sources, and explosives during naval
activities; the sound or impulse received
by animat dosimeters representing
marine mammals distributed in the area
around the modeled activity; and
whether the sound or impulse energy
received by a marine mammal exceeds
the thresholds for effects. Assumptions
in the Navy model intentionally err on
the side of overestimation when there
are unknowns. Naval activities are
modeled as though they would occur
regardless of proximity to marine
mammals, meaning that no mitigation is
considered (e.g., no power down or shut
down) and without any avoidance of the
activity by the animal. As described
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
above in the Estimated Take of Marine
Mammals section, no mortality was
modeled for any species for the TMAA
activities, and therefore the quantitative
post-modeling analysis that allows for
the consideration of mitigation to
prevent mortality, which has been
applied in other Navy rules, was
appropriately not applied here.
(Though, as noted in the Estimated Take
of Marine Mammals section, where the
analysis indicates mitigation would
effectively reduce risk, the modelestimated PTS are considered reduced
to TTS.) NMFS provided input to,
independently reviewed, and concurs
with the Navy on this process and the
Navy’s analysis, which is described in
detail in Section 6 of the Navy’s
rulemaking/LOA application, that was
used to quantify harassment takes for
this rule.
Generally speaking, the Navy and
NMFS anticipate more severe effects
from takes resulting from exposure to
higher received levels (though this is in
no way a strictly linear relationship for
behavioral effects throughout species,
individuals, or circumstances) and less
severe effects from takes resulting from
exposure to lower received levels.
However, there is also growing evidence
of the importance of distance in
predicting marine mammal behavioral
response to sound—i.e., sounds of a
similar level emanating from a more
distant source have been shown to be
less likely to evoke a response of equal
magnitude (DeRuiter 2012, Falcone et
al. 2017). The estimated number of takes
by Level A harassment and Level B
harassment does not equate to the
number of individual animals the Navy
expects to harass (which is lower), but
rather to the instances of take (i.e.,
exposures above the Level A harassment
and Level B harassment threshold) that
are anticipated to occur annually and
over the 7-year period. These instances
may represent either brief exposures
(seconds or minutes) or, in some cases,
longer durations of exposure within a
day. Some individuals may experience
multiple instances of take (meaning over
multiple days) over the course of the 21
day exercise, which means that the
number of individuals taken is smaller
than the total estimated takes. Generally
speaking, the higher the number of takes
as compared to the population
abundance, the more repeated takes of
individuals are likely, and the higher
the actual percentage of individuals in
the population that are likely taken at
least once in a year. We look at this
comparative metric to give us a relative
sense of where a larger portion of a
species is being taken by Navy
PO 00000
Frm 00082
Fmt 4701
Sfmt 4702
activities, where there is a higher
likelihood that the same individuals are
being taken across multiple days, and
where that number of days might be
higher or more likely sequential. Where
the number of instances of take is less
than 100 percent of the abundance and
there is no information to specifically
suggest that a small subset of animals is
being repeatedly taken over a high
number of sequential days, the overall
magnitude is generally considered low,
as it could on one extreme mean that
every take represents a separate
individual in the population being taken
on one day (a very minimal impact) or,
more likely, that some smaller number
of individuals are taken on one day
annually and some are taken on a few
not likely sequential days annually,
while some are not taken at all.
In the ocean, the use of sonar and
other active acoustic sources is often
transient and is unlikely to repeatedly
expose the same individual animals
within a short period, for example
within one specific exercise. However,
for some individuals of some species
repeated exposures across different
activities could occur across the 21-day
period. In short, for some species we
expect that the total anticipated takes
represent exposures of a smaller number
of individuals of which some would be
exposed multiple times, but based on
the nature of the Navy activities and the
movement patterns of marine mammals,
it is unlikely that individuals from most
stocks would be taken over more than
a few non-sequential days. This means
that even where repeated takes of
individuals may occur, they are more
likely to result from non-sequential
exposures from different activities, and,
even if a few individuals were taken on
sequential days, they are not predicted
to be taken for more than a few days in
a row, at most. As described elsewhere,
the nature of the majority of the
exposures would be expected to be of a
less severe nature and based on the
numbers and duration of the activity (no
more than 21 days) any individual
exposed multiple times is still only
taken on a small percentage of the days
of the year.
Physiological Stress Response
Some of the lower level physiological
stress responses (e.g., orientation or
startle response, change in respiration,
change in heart rate) discussed earlier
would likely co-occur with the
predicted harassments, although these
responses are more difficult to detect
and fewer data exist relating these
responses to specific received levels of
sound. Takes by Level A harassment or
Level B harassment, then, may have a
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
stress-related physiological component
as well; however, we would not expect
the Navy’s generally short-term,
intermittent, and (typically in the case
of sonar) transitory activities to create
conditions of long-term continuous
noise leading to long-term physiological
stress responses in marine mammals
that could affect reproduction or
survival.
Behavioral Response
The estimates calculated using the
BRF do not differentiate between the
different types of behavioral responses
that rise to the level of take by Level B
harassment. As described in the Navy’s
application, the Navy identified (with
NMFS’ input) the types of behaviors
that would be considered a take:
Moderate behavioral responses as
characterized in Southall et al. (2007)
(e.g., altered migration paths or dive
profiles, interrupted nursing, breeding
or feeding, or avoidance) that also
would be expected to continue for the
duration of an exposure. The Navy then
compiled the available data indicating
at what received levels and distances
those responses have occurred, and
used the indicated literature to build
biphasic behavioral response curves that
are used to predict how many instances
of Level B harassment by behavioral
disturbance occur in a day. Take
estimates alone do not provide
information regarding the potential
fitness or other biological consequences
of the reactions on the affected
individuals. We therefore consider the
available activity-specific,
environmental, and species-specific
information to determine the likely
nature of the modeled behavioral
responses and the potential fitness
consequences for affected individuals.
Use of sonar and other transducers
would typically be transient and
temporary. The majority of acoustic
effects to individual animals from sonar
and other active sound sources during
training activities would be primarily
from ASW events. It is important to note
that although ASW is one of the warfare
areas of focus during Navy training,
there are significant periods when active
ASW sonars are not in use. Behavioral
reactions are assumed more likely to be
significant during MTEs than during
other ASW activities due to the use of
high-powered ASW sources as well as
the duration (i.e., multiple days) and
scale (i.e., multiple sonar platforms) of
the MTEs.
On the less severe end, exposure to
comparatively lower levels of sound at
a detectably greater distance from the
animal, for a few or several minutes,
could result in a behavioral response
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
such as avoiding an area that an animal
would otherwise have moved through or
fed in, or breaking off one or a few
feeding bouts. More severe effects could
occur when the animal gets close
enough to the source to receive a
comparatively higher level of sound, is
exposed continuously to one source for
a longer time, or is exposed
intermittently to different sources
throughout a day. Such effects might
result in an animal having a more severe
flight response and leaving a larger area
for a day or more or potentially losing
feeding opportunities for a day.
However, such severe behavioral effects
are expected to occur infrequently.
To help assess this, for sonar (MFAS/
HFAS) used in the TMAA, the Navy
provided information estimating the
percentage of animals that may be taken
by Level B harassment under each BRF
that would occur within 6-dB
increments (percentages discussed
below in the Group and SpeciesSpecific Analyses section). As
mentioned above, all else being equal,
an animal’s exposure to a higher
received level is more likely to result in
a behavioral response that is more likely
to lead to adverse effects, which could
more likely accumulate to impacts on
reproductive success or survivorship of
the animal, but other contextual factors
(such as distance) are also important.
The majority of takes by Level B
harassment are expected to be in the
form of milder responses (i.e., lowerlevel exposures that still rise to the level
of take, but would likely be less severe
in the range of responses that qualify as
take) of a generally shorter duration. We
anticipate more severe effects from takes
when animals are exposed to higher
received levels of sound or at closer
proximity to the source. Because species
belonging to taxa that share common
characteristics are likely to respond and
be affected in similar ways, these
discussions are presented within each
species group below in the Group and
Species-Specific Analyses section. As
noted previously in this proposed rule,
behavioral responses vary considerably
between species, between individuals
within a species, and across contexts of
different exposures. Specifically, given a
range of behavioral responses that may
be classified as Level B harassment, to
the degree that higher received levels of
sound are expected to result in more
severe behavioral responses, only a
smaller percentage of the anticipated
Level B harassment from Navy activities
might necessarily be expected to
potentially result in more severe
responses (see the Group and SpeciesSpecific Analyses section below for
PO 00000
Frm 00083
Fmt 4701
Sfmt 4702
49737
more detailed information). To fully
understand the likely impacts of the
predicted/proposed authorized take on
an individual (i.e., what is the
likelihood or degree of fitness impacts),
one must look closely at the available
contextual information, such as the
duration of likely exposures and the
likely severity of the exposures (e.g.,
whether they would occur for a longer
duration over sequential days or the
comparative sound level that would be
received). Ellison et al. (2012) and
Moore and Barlow (2013), among others,
emphasize the importance of context
(e.g., behavioral state of the animals,
distance from the sound source, etc.) in
evaluating behavioral responses of
marine mammals to acoustic sources.
Diel Cycle
Many animals perform vital functions,
such as feeding, resting, traveling, and
socializing on a diel cycle (24-hour
cycle). Behavioral reactions to noise
exposure, when taking place in a
biologically important context, such as
disruption of critical life functions,
displacement, or avoidance of important
habitat, are more likely to be significant
if they last more than one diel cycle or
recur on subsequent days (Southall et
al., 2007). Henderson et al. (2016) found
that ongoing smaller scale events had
little to no impact on foraging dives for
Blainville’s beaked whale, while multiday training events may decrease
foraging behavior for Blainville’s beaked
whale (Manzano-Roth et al., 2016).
Consequently, a behavioral response
lasting less than one day and not
recurring on subsequent days is not
considered severe unless it could
directly affect reproduction or survival
(Southall et al., 2007). Note that there is
a difference between multiple-day
substantive behavioral reactions and
multiple-day anthropogenic activities.
For example, just because an at-sea
exercise lasts for multiple days does not
necessarily mean that individual
animals are either exposed to those
exercises for multiple days or, further,
exposed in a manner resulting in a
sustained multiple day substantive
behavioral response. Large multi-day
Navy exercises such as ASW activities,
typically include vessels that are
continuously moving at speeds typically
10–15 kn (19–28 km/hr), or higher, and
likely cover large areas that are
relatively far from shore (typically more
than 3 nmi (6 km) from shore) and in
waters greater than 600 ft (183 m) deep.
Additionally marine mammals are
moving as well, which would make it
unlikely that the same animal could
remain in the immediate vicinity of the
ship for the entire duration of the
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49738
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
exercise. Further, the Navy does not
necessarily operate active sonar the
entire time during an exercise. While it
is certainly possible that these sorts of
exercises could overlap with individual
marine mammals multiple days in a row
at levels above those anticipated to
result in a take, because of the factors
mentioned above, it is considered
unlikely for the majority of takes.
However, it is also worth noting that the
Navy conducts many different types of
noise-producing activities over the
course of the 21-day exercise, and it is
likely that some marine mammals will
be exposed to more than one activity
and taken on multiple days, even if they
are not sequential.
Durations of Navy activities utilizing
tactical sonar sources and explosives
vary and are fully described in
Appendix A (Navy Activity
Descriptions) of the 2020 GOA DSEIS/
OEIS. Sonar used during ASW would
impart the greatest amount of acoustic
energy of any category of sonar and
other transducers analyzed in the
Navy’s rulemaking/LOA application and
include hull-mounted, towed array,
sonobuoy, and helicopter dipping
sonars. Most ASW sonars are MFAS (1–
10 kHz); however, some sources may
use higher frequencies. ASW training
activities using hull mounted sonar
proposed for the TMAA generally last
for only a few hours (see Appendix A
(Navy Activity Descriptions) of the 2020
GOA DSEIS/OEIS). Some ASW training
activities typically last about 8 hours.
Because of the need to train in a large
variety of situations, the Navy does not
typically conduct successive ASW
exercises in the same locations. Given
the average length of ASW exercises
(times of sonar use) and typical vessel
speed, combined with the fact that the
majority of the cetaceans would not
likely remain in proximity to the sound
source, it is unlikely that an animal
would be exposed to MFAS/HFAS at
levels or durations likely to result in a
substantive response that would then be
carried on for more than 1 day or on
successive days (and as noted
previously, no LFAS use is planned by
the Navy).
Most planned explosive events are
scheduled to occur over a short duration
(1–3 hours); however, the explosive
component of these activities only lasts
for minutes. Although explosive
exercises may sometimes be conducted
in the same general areas repeatedly,
because of their short duration and the
fact that they are in the open ocean and
animals can easily move away, it is
similarly unlikely that animals would
be exposed for long, continuous
amounts of time, or demonstrate
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
sustained behavioral responses. All of
these factors make it unlikely that
individuals would be exposed to the
exercise for extended periods or on
consecutive days, though some
individuals may be exposed on multiple
days.
Assessing the Number of Individuals
Taken and the Likelihood of Repeated
Takes
As described previously, Navy
modeling uses the best available science
to predict the instances of exposure
above certain acoustic thresholds,
which are equated, as appropriate, to
harassment takes (and further corrected
to account for mitigation and
avoidance). As further noted, for active
acoustics it is more challenging to parse
out the number of individuals taken by
Level B harassment and the number of
times those individuals are taken from
this larger number of instances. One
method that NMFS uses to help better
understand the overall scope of the
impacts is to compare these total
instances of take against the abundance
of that species (or stock if applicable).
For example, if there are 100 harassment
takes in a population of 100, one can
assume either that every individual was
exposed above acoustic thresholds in no
more than one day, or that some smaller
number were exposed in one day but a
few of those individuals were exposed
multiple days within a year and a few
were not exposed at all. Where the
instances of take exceed 100 percent of
the population, multiple takes of some
individuals are predicted and expected
to occur within a year. Generally
speaking, the higher the number of takes
as compared to the population
abundance, the more multiple takes of
individuals are likely, and the higher
the actual percentage of individuals in
the population that are likely taken at
least once in a year. We look at this
comparative metric to give us a relative
sense of where larger portions of the
species or stock are being taken by Navy
activities and where there is a higher
likelihood that the same individuals are
being taken across multiple days and
where that number of days might be
higher. It also provides a relative picture
of the scale of impacts to each species
or stock.
In the ocean, unlike a modeling
simulation with static animals, the use
of sonar and other active acoustic
sources is often transient, and is
unlikely to repeatedly expose the same
individual animals within a short
period, for example within one specific
exercise. However, some repeated
exposures across different activities
could occur over the year with more
PO 00000
Frm 00084
Fmt 4701
Sfmt 4702
resident species. Nonetheless, the
episodic nature of activities in the
TMAA (21 days per year) would mean
less frequent exposures as compared to
some other ranges. In short, we expect
that for some stocks, the total
anticipated takes represent exposures of
a smaller number of individuals of
which some could be exposed multiple
times, but based on the nature of the
Navy’s activities and the movement
patterns of marine mammals, it is
unlikely that individuals of most
species or stocks would be taken over
more than a few non-sequential days
within a year.
When calculating the proportion of a
population affected by takes (e.g., the
number of takes divided by population
abundance), which can also be helpful
in estimating the number of days over
which some individuals may be taken,
it is important to choose an appropriate
population estimate against which to
make the comparison. The SARs, where
available, provide the official
population estimate for a given species
or stock in U.S. waters in a given year
(and are typically based solely on the
most recent survey data). When the
stock is known to range well outside of
U.S. Exclusive Economic Zone (EEZ)
boundaries, population estimates based
on surveys conducted only within the
U.S. EEZ are known to be
underestimates. The information used to
estimate take includes the best available
survey abundance data to model density
layers. Accordingly, in calculating the
percentage of takes versus abundance
for each species or stock in order to
assist in understanding both the
percentage of the species or stock
affected, as well as how many days
across a year individuals could be taken,
we use the data most appropriate for the
situation. For the GOA Study Area, for
all species and stocks except for beaked
whales for which SAR data are
unavailable, the most recent NMFS
SARs are used to calculate the
proportion of a population affected by
takes.
The estimates found in NMFS’ SARs
remain the official estimates of stock
abundance where they are current.
These estimates are typically generated
from the most recent shipboard and/or
aerial surveys conducted. In some cases,
NMFS’ abundance estimates show
substantial year-to-year variability.
However, for highly migratory species
(e.g., large whales) or those whose
geographic distribution extends well
beyond the boundaries of the GOA
Study Area (e.g., populations with
distribution along the entire eastern
Pacific Ocean rather than just the GOA
Study Area), comparisons to the SAR
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
are appropriate. Many of the stocks
present in the GOA Study Area have
ranges significantly larger than the GOA
Study Area and that abundance is
captured by the SAR. A good
descriptive example is migrating large
whales, which occur seasonally in the
GOA. Therefore, at any one time there
may be a stable number of animals, but
over the course of the potential activity
period (April to October), the entire
population could occur in the GOA
Study Area. Therefore, comparing the
estimated takes to an abundance, in this
case the SAR abundance, which
represents the total population, may be
more appropriate than modeled
abundances for only the GOA Study
Area.
Temporary Threshold Shift
NMFS and the Navy have estimated
that most species or stocks of marine
mammals in the TMAA may sustain
some level of TTS from active sonar. As
mentioned previously, in general, TTS
can last from a few minutes to days, be
of varying degree, and occur across
various frequency bandwidths, all of
which determine the severity of the
impacts on the affected individual,
which can range from minor to more
severe. Table 41 to Table 46 indicate the
number of takes by TTS that may be
incurred by different species and stocks
from exposure to active sonar and
explosives. The TTS sustained by an
animal is primarily classified by three
characteristics:
1. Frequency—Available data (of midfrequency hearing specialists exposed to
mid- or high-frequency sounds; Southall
et al., 2007) suggest that most TTS
occurs in the frequency range of the
source up to one octave higher than the
source (with the maximum TTS at 1⁄2
octave above). The Navy’s MF sources,
which are the highest power and most
numerous sources and the ones that
cause the most take, utilize the 1–10
kHz frequency band, which suggests
that if TTS were to be induced by any
of these MF sources it would be in a
frequency band somewhere between
approximately 2 and 20 kHz, which is
in the range of communication calls for
many odontocetes, but below the range
of the echolocation signals used for
foraging. There are fewer hours of HF
source use and the sounds would
attenuate more quickly, plus they have
lower source levels, but if an animal
were to incur TTS from these sources,
it would cover a higher frequency range
(sources are between 10 and 100 kHz,
which means that TTS could range up
to 200 kHz), which could overlap with
the range in which some odontocetes
communicate or echolocate. However,
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
HF systems are typically used less
frequently and for shorter time periods
than surface ship and aircraft MF
systems, so TTS from these sources is
unlikely. As noted previously, the Navy
proposes no LFAS use for the activities
in this rulemaking. The frequency
provides information about the cues to
which a marine mammal may be
temporarily less sensitive, but not the
degree or duration of sensitivity loss.
The majority of sonar sources from
which TTS may be incurred occupy a
narrow frequency band, which means
that the TTS incurred would also be
across a narrower band (i.e., not
affecting the majority of an animal’s
hearing range). TTS from explosives
would be broadband.
2. Degree of the shift (i.e., by how
many dB the sensitivity of the hearing
is reduced)—Generally, both the degree
of TTS and the duration of TTS will be
greater if the marine mammal is exposed
to a higher level of energy (which would
occur when the peak dB level is higher
or the duration is longer). The threshold
for the onset of TTS was discussed
previously in this rule. An animal
would have to approach closer to the
source or remain in the vicinity of the
sound source appreciably longer to
increase the received SEL, which would
be difficult considering the Lookouts
and the nominal speed of an active
sonar vessel (10–15 kn; 19–28 km/hr)
and the relative motion between the
sonar vessel and the animal. In the TTS
studies discussed in the Potential
Effects of Specified Activities on Marine
Mammals and their Habitat section,
some using exposures of almost an hour
in duration or up to 217 SEL, most of
the TTS induced was 15 dB or less,
though Finneran et al. (2007) induced
43 dB of TTS with a 64-second exposure
to a 20 kHz source. However, since any
hull-mounted sonar such as the SQS–53
(MFAS), emits a ping typically every 50
seconds, incurring those levels of TTS is
highly unlikely. Since any hullmounted sonar, such as the SQS–53,
engaged in anti-submarine warfare
training would be moving at between 10
and 15 kn (19–28 km/hr) and nominally
pinging every 50 seconds, the vessel
would have traveled a minimum
distance of approximately 257 m during
the time between those pings. A
scenario could occur where an animal
does not leave the vicinity of a ship or
travels a course parallel to the ship,
however, the close distances required
make TTS exposure unlikely. For a
Navy vessel moving at a nominal 10 kn
(19 km/hr), it is unlikely a marine
mammal could maintain speed parallel
PO 00000
Frm 00085
Fmt 4701
Sfmt 4702
49739
to the ship and receive adequate energy
over successive pings to suffer TTS.
In short, given the anticipated
duration and levels of sound exposure,
we would not expect marine mammals
to incur more than relatively low levels
of TTS (i.e., single digits of sensitivity
loss). To add context to this degree of
TTS, individual marine mammals may
regularly experience variations of 6 dB
differences in hearing sensitivity across
time (Finneran et al., 2000, 2002;
Schlundt et al., 2000).
3. Duration of TTS (recovery time)—
In the TTS laboratory studies (as
discussed in the Potential Effects of
Specified Activities on Marine
Mammals and their Habitat section),
some using exposures of almost an hour
in duration or up to 217 SEL, almost all
individuals recovered within 1 day (or
less, often in minutes), although in one
study (Finneran et al., 2007), recovery
took 4 days.
Based on the range of degree and
duration of TTS reportedly induced by
exposures to non-pulse sounds of
energy higher than that to which freeswimming marine mammals in the field
are likely to be exposed during MFAS/
HFAS training exercises in the TMAA,
it is unlikely that marine mammals
would ever sustain a TTS from MFAS
that alters their sensitivity by more than
20 dB for more than a few hours—and
any incident of TTS would likely be far
less severe due to the short duration of
the majority of the events during the 21
days and the speed of a typical vessel,
especially given the fact that the higher
power sources resulting in TTS are
predominantly intermittent, which have
been shown to result in shorter
durations of TTS. Also, for the same
reasons discussed in the Preliminary
Analysis and Negligible Impact
Determination—Diel Cycle section, and
because of the short distance within
which animals would need to approach
the sound source, it is unlikely that
animals would be exposed to the levels
necessary to induce TTS in subsequent
time periods such that their recovery is
impeded. Additionally, though the
frequency range of TTS that marine
mammals might sustain would overlap
with some of the frequency ranges of
their vocalization types, the frequency
range of TTS from MFAS would not
usually span the entire frequency range
of one vocalization type, much less span
all types of vocalizations or other
critical auditory cues.
Tables 41 to 46 indicate the number
of incidental takes by TTS for each
species or stock that are likely to result
from the Navy’s activities. As a general
point, the majority of these TTS takes
are the result of exposure to hull-
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49740
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
mounted MFAS (MF narrower band
sources), with fewer from explosives
(broad-band lower frequency sources),
and even fewer from HFAS sources
(narrower band). As described above,
we expect the majority of these takes to
be in the form of mild (single-digit),
short-term (minutes to hours), narrower
band (only affecting a portion of the
animal’s hearing range) TTS. This
means that for one to several times
within the 21 days, for several minutes
to maybe a few hours at most each, a
taken individual will have slightly
diminished hearing sensitivity (slightly
more than natural variation, but
nowhere near total deafness). More
often than not, such an exposure would
occur within a narrower mid- to higher
frequency band that may overlap part
(but not all) of a communication,
echolocation, or predator range, but
sometimes across a lower or broader
bandwidth. The significance of TTS is
also related to the auditory cues that are
germane within the time period that the
animal incurs the TTS. For example, if
an odontocete has TTS at echolocation
frequencies, but incurs it at night when
it is resting and not feeding, it is not
impactful. In short, the expected results
of any one of these limited number of
mild TTS occurrences could be that (1)
it does not overlap signals that are
pertinent to that animal in the given
time period, (2) it overlaps parts of
signals that are important to the animal,
but not in a manner that impairs
interpretation, or (3) it reduces
detectability of an important signal to a
small degree for a short amount of
time—in which case the animal may be
aware and be able to compensate (but
there may be slight energetic cost), or
the animal may have some reduced
opportunities (e.g., to detect prey) or
reduced capabilities to react with
maximum effectiveness (e.g., to detect a
predator or navigate optimally).
However, given the small number of
times that any individual might incur
TTS, the low degree of TTS and the
short anticipated duration, and the low
likelihood that one of these instances
would occur in a time period in which
the specific TTS overlapped the entirety
of a critical signal, it is unlikely that
TTS of the nature expected to result
from the Navy activities would result in
behavioral changes or other impacts that
would impact any individual’s (of any
hearing sensitivity) reproduction or
survival.
Auditory Masking or Communication
Impairment
The ultimate potential impacts of
masking on an individual (if it were to
occur) are similar to those discussed for
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
TTS, but an important difference is that
masking only occurs during the time of
the signal, versus TTS, which continues
beyond the duration of the signal.
Fundamentally, masking is referred to
as a chronic effect because one of the
key harmful components of masking is
its duration—the fact that an animal
would have reduced ability to hear or
interpret critical cues becomes much
more likely to cause a problem the
longer it is occurring. Also inherent in
the concept of masking is the fact that
the potential for the effect is only
present during the times that the animal
and the source are in close enough
proximity for the effect to occur (and
further, this time period would need to
coincide with a time that the animal
was utilizing sounds at the masked
frequency). As our analysis has
indicated, because of the relative
movement of vessels and the species
involved in this rule, we do not expect
the exposures with the potential for
masking to be of a long duration. In
addition, masking is fundamentally
more of a concern at lower frequencies,
because low frequency signals propagate
significantly further than higher
frequencies and because they are more
likely to overlap both the narrower LF
calls of mysticetes, as well as many noncommunication cues such as fish and
invertebrate prey, and geologic sounds
that inform navigation (although the
Navy proposes no LFAS use for the
activities in this rulemaking). Masking
is also more of a concern from
continuous sources (versus intermittent
sonar signals) where there is no quiet
time between pulses within which
auditory signals can be detected and
interpreted. For these reasons, dense
aggregations of, and long exposure to,
continuous LF activity are much more
of a concern for masking, whereas
comparatively short-term exposure to
the predominantly intermittent pulses
of often narrow frequency range MFAS
or HFAS, or explosions are not expected
to result in a meaningful amount of
masking. While the Navy occasionally
uses LF and more continuous sources
(although, as noted above, the Navy
proposes no LFAS use for the activities
in this rulemaking), it is not in the
contemporaneous aggregate amounts
that would accrue to a masking concern.
Specifically, the nature of the activities
and sound sources used by the Navy do
not support the likelihood of a level of
masking accruing that would have the
potential to affect reproductive success
or survival. Additional detail is
provided below.
Standard hull-mounted MFAS
typically pings every 50 seconds. Some
PO 00000
Frm 00086
Fmt 4701
Sfmt 4702
hull-mounted anti-submarine sonars can
also be used in an object detection mode
known as ‘‘Kingfisher’’ mode (e.g., used
on vessels when transiting to and from
port) where pulse length is shorter but
pings are much closer together in both
time and space since the vessel goes
slower when operating in this mode
(note also that the duty cycle for MF11
and MF12 sources is greater than 80
percent). For the majority of other
sources, the pulse length is significantly
shorter than hull-mounted active sonar,
on the order of several microseconds to
tens of milliseconds. Some of the
vocalizations that many marine
mammals make are less than one second
long, so, for example with hull-mounted
sonar, there would be a 1 in 50 chance
(only if the source was in close enough
proximity for the sound to exceed the
signal that is being detected) that a
single vocalization might be masked by
a ping. However, when vocalizations (or
series of vocalizations) are longer than
one second, masking would not occur.
Additionally, when the pulses are only
several microseconds long, the majority
of most animals’ vocalizations would
not be masked.
Most ASW sonars and
countermeasures use MF frequencies
and a few use HF frequencies. Most of
these sonar signals are limited in the
temporal, frequency, and spatial
domains. The duration of most
individual sounds is short, lasting up to
a few seconds each. A few systems
operate with higher duty cycles or
nearly continuously, but they typically
use lower power, which means that an
animal would have to be closer, or in
the vicinity for a longer time, to be
masked to the same degree as by a
higher level source. Nevertheless,
masking could occasionally occur at
closer ranges to these high-duty cycle
and continuous active sonar systems,
but as described previously, it would be
expected to be of a short duration when
the source and animal are in close
proximity. While data are limited on
behavioral responses of marine
mammals to continuously active sonars
(Isojunno et al., 2020), mysticete species
are known to be able to habituate to
novel and continuous sounds (Nowacek
et al., 2004), suggesting that they are
likely to have similar responses to highduty cycle sonars. Furthermore, most of
these systems are hull-mounted on
surface ships with the ships moving at
least 10 kn (19 km/hr), and it is unlikely
that the ship and the marine mammal
would continue to move in the same
direction and the marine mammal
subjected to the same exposure due to
that movement. Most ASW activities are
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
geographically dispersed and last for
only a few hours, often with
intermittent sonar use even within this
period. Most ASW sonars also have a
narrow frequency band (typically less
than one-third octave). These factors
reduce the likelihood of sources causing
significant masking. HF signals (above
10 kHz) attenuate more rapidly in the
water due to absorption than do lower
frequency signals, thus producing only
a very small zone of potential masking.
If masking or communication
impairment were to occur briefly, it
would more likely be in the frequency
range of MFAS (the more powerful
source), which overlaps with some
odontocete vocalizations (but few
mysticete vocalizations); however, it
would likely not mask the entirety of
any particular vocalization,
communication series, or other critical
auditory cue, because the signal length,
frequency, and duty cycle of the MFAS/
HFAS signal does not perfectly resemble
the characteristics of any single marine
mammal species’ vocalizations.
Other sources used in Navy training
that are not explicitly addressed above,
many of either higher frequencies
(meaning that the sounds generated
attenuate even closer to the source) or
lower amounts of operation, are
similarly not expected to result in
masking. For the reasons described here,
any limited masking that could
potentially occur would be minor and
short-term.
In conclusion, masking is more likely
to occur in the presence of broadband,
relatively continuous noise sources such
as from vessels, however, the duration
of temporal and spatial overlap with any
individual animal and the spatially
separated sources that the Navy uses
would not be expected to result in more
than short-term, low impact masking
that would not affect reproduction or
survival.
PTS From Sonar Acoustic Sources and
Explosives and Non-Auditory Tissue
Damage From Explosives
Tables 41 to 46 indicate the number
of individuals of each species or stock
for which Level A harassment in the
form of PTS resulting from exposure to
active sonar and/or explosives is
estimated to occur. The Northeast
Pacific stock of fin whale, Alaska stock
of Dall’s porpoise, and California stock
of Northern elephant seal are the only
stocks which may incur PTS (from sonar
and explosives). For all other species/
stocks only take by Level B harassment
(behavioral disturbance and/or TTS) is
anticipated. No species/stocks have the
potential to incur non-auditory tissue
damage from training activities.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
Data suggest that many marine
mammals would deliberately avoid
exposing themselves to the received
levels of active sonar necessary to
induce injury by moving away from or
at least modifying their path to avoid a
close approach. Additionally, in the
unlikely event that an animal
approaches the sonar-emitting vessel at
a close distance, NMFS has determined
that the mitigation measures (i.e.,
shutdown/powerdown zones for active
sonar) would typically ensure that
animals would not be exposed to
injurious levels of sound. As discussed
previously, the Navy utilizes both aerial
(when available) and passive acoustic
monitoring (during ASW exercises,
passive acoustic detections are used as
a cue for Lookouts’ visual observations
when passive acoustic assets are already
participating in an activity) in addition
to Lookouts on vessels to detect marine
mammals for mitigation
implementation. As discussed
previously, the Navy utilized a postmodeling quantitative assessment to
adjust the take estimates based on
avoidance and the likely success of
some portion of the mitigation
measures. As is typical in predicting
biological responses, it is challenging to
predict exactly how avoidance and
mitigation would affect the take of
marine mammals. Therefore, in
conducting the post-modeling
quantitative assessment, the Navy erred
on the side of caution in choosing a
method that would more likely still
overestimate the take by PTS to some
degree. Nonetheless, these Level A
harassment take numbers represent the
maximum number of instances in which
marine mammals would be reasonably
expected to incur PTS, and we have
analyzed them accordingly.
If a marine mammal is able to
approach a surface vessel within the
distance necessary to incur PTS in spite
of the mitigation measures, the likely
speed of the vessel (nominally 10–15 kn
(19–28 km/hr)) and relative motion of
the vessel would make it very difficult
for the animal to remain in range long
enough to accumulate enough energy to
result in more than a mild case of PTS.
As discussed previously in relation to
TTS, the likely consequences to the
health of an individual that incurs PTS
can range from mild to more serious
dependent upon the degree of PTS and
the frequency band it is in. The majority
of any PTS incurred as a result of
exposure to Navy sources would be
expected to be in a narrow band in the
2–20 kHz range (resulting from the most
powerful hull-mounted sonar) and
could overlap a small portion of the
PO 00000
Frm 00087
Fmt 4701
Sfmt 4702
49741
communication frequency range of
many odontocetes, whereas other
marine mammal groups have
communication calls at lower
frequencies. Regardless of the frequency
band, the more important point in this
case is that any PTS accrued as a result
of exposure to Navy activities would be
expected to be of a small amount (single
digits of dB hearing loss). Permanent
loss of some degree of hearing is a
normal occurrence for older animals,
and many animals are able to
compensate for the shift, both in old age
or at younger ages as the result of
stressor exposure. While a small loss of
hearing sensitivity may include some
degree of energetic costs for
compensating or may mean some small
loss of opportunities or detection
capabilities, at the expected scale it
would be unlikely to impact behaviors,
opportunities, or detection capabilities
to a degree that would interfere with
reproductive success or survival.
The Navy implements mitigation
measures (described in the Proposed
Mitigation Measures section) during
explosive activities, including delaying
detonations when a marine mammal is
observed in the mitigation zone. Nearly
all explosive events would occur during
daylight hours to improve the
sightability of marine mammals and
thereby improve mitigation
effectiveness. Observing for marine
mammals during the explosive activities
would include visual and passive
acoustic detection methods (when they
are available and part of the activity)
before the activity begins, in order to
cover the mitigation zones that can
range from 200 yd (182.9 m) to 2,500 yd
(2,286 m) depending on the source (e.g.,
explosive bombs; see Table 34 and
Table 35). For all of these reasons, the
proposed mitigation measures
associated with explosives are expected
to further ensure that no non-auditory
tissue damage occurs to any potentially
affected species, and no species are
anticipated to incur non-auditory tissue
damage during the period of the
proposed rule.
Group and Species-Specific Analyses
The maximum amount and type of
incidental take of marine mammals
reasonably likely to occur and therefore
proposed to be authorized from
exposures to sonar and other active
acoustic sources and in-air explosions at
or above the water surface during the 7year training period are shown in Table
30. The vast majority of predicted
exposures (greater than 99 percent) are
expected to be non-injurious Level B
harassment (TTS and behavioral
disturbance) from acoustic and
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49742
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
explosive sources during training
activities at relatively low received
levels. A small number of takes by Level
A harassment (PTS only) are predicted
for three species (Dall’s porpoise, fin
whales, and Northern elephant seals).
In the discussions below, the
estimated takes by Level B harassment
represent instances of take, not the
number of individuals taken (the less
frequent Level A harassment takes are
far more likely to be associated with
separate individuals), and in some cases
individuals may be taken more than one
time. Below, we compare the total take
numbers (including PTS, TTS, and
behavioral disturbance) for species or
stocks to their associated abundance
estimates to evaluate the magnitude of
impacts across the species and to
individuals. Generally, when an
abundance percentage comparison is
below 100, it means that that percentage
or less of the individuals would be
affected (i.e., some individuals would
not be taken at all), that the average for
those taken is one day per year, and that
we would not expect any individuals to
be taken more than a few times during
the 21 days per year. When it is more
than 100 percent, it means there would
definitely be some number of repeated
takes of individuals. For example, if the
percentage is 300, the average would be
each individual is taken on 3 days in a
year if all were taken, but it is more
likely that some number of individuals
would be taken more than three times
and some number of individuals fewer
or not at all. While it is not possible to
know the maximum number of days
across which individuals of a stock
might be taken, in acknowledgement of
the fact that it is more than the average,
for the purposes of this analysis, we
assume a number approaching twice the
average. For example, if the percentage
of take compared to the abundance is
800, we estimate that some individuals
might be taken as many as 16 times.
Those comparisons are included in the
sections below.
To assist in understanding what this
analysis means, we clarify a few issues
related to estimated takes and the
analysis here. An individual that incurs
a PTS or TTS take may sometimes, for
example, also be subject to behavioral
disturbance at the same time. As
described above in this section, the
degree of PTS, and the degree and
duration of TTS, expected to be
incurred from the Navy’s activities are
not expected to impact marine
mammals such that their reproduction
or survival could be affected. Similarly,
data do not suggest that a single
instance in which an animal accrues
PTS or TTS and is also subjected to
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
behavioral disturbance would result in
impacts to reproduction or survival.
Alternately, we recognize that if an
individual is subjected to behavioral
disturbance repeatedly for a longer
duration and on consecutive days,
effects could accrue to the point that
reproductive success is jeopardized,
although those sorts of impacts are not
expected to result from these activities.
Accordingly, in analyzing the number of
takes and the likelihood of repeated and
sequential takes, we consider the total
takes, not just the takes by Level B
harassment by behavioral disturbance,
so that individuals potentially exposed
to both threshold shift and behavioral
disturbance are appropriately
considered. The number of Level A
harassment takes by PTS are so low (and
zero in most cases) compared to
abundance numbers that it is considered
highly unlikely that any individual
would be taken at those levels more
than once.
Occasional, milder behavioral
reactions are unlikely to cause long-term
consequences for individual animals or
populations, and even if some smaller
subset of the takes are in the form of a
longer (several hours or a day) and more
severe response, if they are not expected
to be repeated over sequential days,
impacts to individual fitness are not
anticipated. Nearly all studies and
experts agree that infrequent exposures
of a single day or less are unlikely to
impact an individual’s overall energy
budget (Farmer et al., 2018; Harris et al.,
2017; King et al., 2015; NAS 2017; New
et al., 2014; Southall et al., 2007;
Villegas-Amtmann et al., 2015).
If impacts to individuals are of a
magnitude or severity such that either
repeated and sequential higher severity
impacts occur (the probability of this
goes up for an individual the higher
total number of takes it has) or the total
number of moderate to more severe
impacts increases substantially,
especially if occurring across sequential
days, then it becomes more likely that
the aggregate effects could potentially
interfere with feeding enough to reduce
energy budgets in a manner that could
impact reproductive success via longer
cow-calf intervals, terminated
pregnancies, or calf mortality. It is
important to note that these impacts
would only accrue to females, which
only comprise a portion of the
population (typically approximately 50
percent). Based on energetic models, it
takes energetic impacts of a significantly
greater magnitude to cause the death of
an adult marine mammal, and females
will always terminate a pregnancy or
stop lactating before allowing their
health to deteriorate. Also, the death of
PO 00000
Frm 00088
Fmt 4701
Sfmt 4702
an adult female has significantly more
impact on population growth rates than
reductions in reproductive success,
while the death of an adult male has
very little effect on population growth
rates. However, as will be explained
further in the sections below, the
severity and magnitude of takes
expected to result from Navy activities
in the TMAA are such that energetic
impacts of a scale that might affect
reproductive success are not expected to
occur at all.
The analyses below in some cases
address species collectively if they
occupy the same functional hearing
group (i.e., low, mid, and highfrequency cetaceans), share similar life
history strategies, and/or are known to
behaviorally respond similarly to
acoustic stressors. Because some of
these groups or species share
characteristics that inform the impact
analysis similarly, it would be
duplicative to repeat the same analysis
for each species. In addition, similar
species typically have the same hearing
capabilities and behaviorally respond in
the same manner.
Thus, our analysis below considers
the effects of the Navy’s activities on
each affected species or stock even
where discussion is organized by
functional hearing group and/or
information is evaluated at the group
level. Where there are meaningful
differences between a species or stock
that would further differentiate the
analysis, they are either described
within the section or the discussion for
those species or stocks is included as a
separate subsection. Specifically below,
we first provide broad discussion of the
expected effects on the mysticete,
odontocete, and pinniped groups
generally, and then differentiate into
further groups as appropriate.
Mysticetes
This section builds on the broader
discussion above and brings together the
discussion of the different types and
amounts of take that different species
and stocks would likely incur, the
applicable mitigation, and the status of
the species and stocks to support the
preliminary negligible impact
determinations for each species or stock.
We have described (earlier in this
section) the unlikelihood of any
masking having effects that would
impact the reproduction or survival of
any of the individual marine mammals
affected by the Navy’s activities. We
have also described above in the
Potential Effects of Specified Activities
on Marine Mammals and their Habitat
section the unlikelihood of any habitat
impacts having effects that would
E:\FR\FM\11AUP2.SGM
11AUP2
49743
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
impact the reproduction or survival of
any of the individual marine mammals
affected by the Navy’s activities. For
mysticetes, there is no predicted nonauditory tissue damage from explosives
for any species, and only two fin whales
could be taken by PTS by exposure to
in-air explosions at or above the water
surface. Much of the discussion below
focuses on the behavioral effects and the
mitigation measures that reduce the
probability or severity of effects.
Because there are species-specific and
stock-specific considerations, at the end
of the section we break out our findings
on a species-specific and, for one
species, stock-specific basis.
In Table 41 below for mysticetes, we
indicate for each species and stock the
total annual numbers of take by Level A
harassment and Level B harassment,
and a number indicating the instances
of total take as a percentage of
abundance.
TABLE 41—ANNUAL ESTIMATED TAKES BY LEVEL B HARASSMENT AND LEVEL A HARASSMENT FOR MYSTICETES AND
NUMBER INDICATING THE INSTANCES OF TOTAL TAKE AS A PERCENTAGE OF SPECIES/STOCK ABUNDANCE
Instances of indicated types of incidental take 1
Level B harassment
Species
Stock
Behavioral
disturbance
North Pacific right whale .......
Humpback whale ...................
Blue whale .............................
Fin whale ...............................
Sei whale ...............................
Minke whale ..........................
Gray whale ............................
Eastern North Pacific ............
California, Oregon, & Washington.
Central North Pacific .............
Western North Pacific ...........
Central North Pacific .............
Eastern North Pacific ............
Northeast Pacific ...................
Eastern North Pacific ............
Alaska ....................................
Eastern North Pacific ............
Level A
harassment
TTS
(may also
include
disturbance)
Total takes
2
8
0
0
11
68
0
3
32
1,127
34
44
0
0
0
0
0
2
0
0
0
0
4
115
3
6
34
Instances of
total take as
percentage of
abundance
PTS
1
2
33
Abundance
(NMFS
SARs) 2
3
10
31
4,973
9.7
<1
79
10,103
1,107
133
1,898
4 3,168
519
5 389
26,960
<1
<1
2.3
1.9
39.3
7.1
12.9
<1
33
3
36
1,244
37
50
34
lotter on DSK11XQN23PROD with PROPOSALS2
1 Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate individuals, especially for behavioral disturbance.
2 Presented in the 2021 draft SARs or most recent SAR.
3 The Navy’s Acoustic Effects Model estimated zero takes for each of these stocks. However, NMFS conservatively proposes to authorize take by Level B harassment of one group of Western North Pacific humpback whale and one group of Eastern North Pacific gray whale. The annual take estimates reflect the average
group sizes of on- and off-effort survey sightings of humpback whale and gray whale (excluding an outlier of an estimated 25 gray whales in one group) reported in
Rone et al. (2017).
4 The SAR reports this stock abundance assessment as provisional and notes that it is an underestimate for the entire stock because it is based on surveys which
covered only a small portion of the stock’s range.
5 The 2018 final SAR (most recent SAR) for the Alaska stock of minke whales reports the stock abundance as unknown because only a portion of the stock’s range
has been surveyed. To be conservative, for this stock we report the smallest estimated abundance produced during recent surveys.
The majority of takes by harassment
of mysticetes in the TMAA would be
caused by anti-submarine warfare
(ASW) activities. Anti-submarine
activities include sources from the
MFAS bin (which includes hullmounted sonar). They are high level,
narrowband sources in the 1–10 kHz
range, which intersect what is estimated
to be the most sensitive area of hearing
for mysticetes. They also are used in a
large portion of exercises (see Table 1
and Table 3). Most of the takes (88
percent) from the MF1 bin in the TMAA
would result from received levels
between 166 and 178 dB SPL, while
another 11 percent would result from
exposure between 160 and 166 dB SPL.
For the remaining active sonar bin
types, the percentages are as follows:
MF4 = 97 percent between 142 and 154
dB SPL and MF5 = 97 percent between
118 and 142 dB SPL. For mysticetes,
exposure to explosives would result in
comparatively smaller numbers of takes
by Level B harassment by behavioral
disturbance (0–11 per stock) and TTS
takes (0–2 per stock). Based on this
information, the majority of the takes by
Level B harassment by behavioral
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
disturbance would be expected to be of
low to sometimes moderate severity and
of a relatively shorter duration.
Exposure to explosives would also
result in two takes by Level A
harassment by PTS of the Northeast
Pacific stock of fin whale. No mortality
or serious injury and no Level A
harassment from non-auditory tissue
damage from training activities is
anticipated or proposed for
authorization for any species or stock.
Research and observations show that
if mysticetes are exposed to sonar or
other active acoustic sources they may
react in a number of ways depending on
the characteristics of the sound source,
their experience with the sound source,
and whether they are migrating or on
seasonal feeding or breeding grounds.
Behavioral reactions may include
alerting, breaking off feeding dives and
surfacing, diving or swimming away, or
no response at all (DOD, 2017;
Nowacek, 2007; Richardson, 1995;
Southall et al., 2007). Overall,
mysticetes have been observed to be
more reactive to acoustic disturbance
when a noise source is located directly
on their migration route. Mysticetes
PO 00000
Frm 00089
Fmt 4701
Sfmt 4702
disturbed while migrating could pause
their migration or route around the
disturbance, while males en route to
breeding grounds have been shown to
be less responsive to disturbances.
Although some may pause temporarily,
they would resume migration shortly
after the exposure ends. Animals
disturbed while engaged in other
activities such as feeding or
reproductive behaviors may be more
likely to ignore or tolerate the
disturbance and continue their natural
behavior patterns. Alternately, adult
females with calves may be more
responsive to stressors.
As noted in the Potential Effects of
Specified Activities on Marine
Mammals and Their Habitat section,
while there are multiple examples from
behavioral response studies of
odontocetes ceasing their feeding dives
when exposed to sonar pulses at certain
levels, blue whales were less likely to
show a visible response to sonar
exposures at certain levels when feeding
than when traveling. However,
Goldbogen et al. (2013) indicated some
horizontal displacement of deep
foraging blue whales in response to
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49744
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
simulated MFAS. Southall et al. (2019b)
observed that after exposure to
simulated and operational midfrequency active sonar, more than 50
percent of blue whales in deep-diving
states responded to the sonar, while no
behavioral response was observed in
shallow-feeding blue whales. Southall et
al. (2019b) noted that the behavioral
responses they observed were generally
brief, of low to moderate severity, and
highly dependent on exposure context
(behavioral state, source-to-whale
horizontal range, and prey availability).
Richardson et al. (1995) noted that
avoidance (temporary displacement of
an individual from an area) reactions are
the most obvious manifestations of
disturbance in marine mammals.
Avoidance is qualitatively different
from the startle or flight response, but
also differs in the magnitude of the
response (i.e., directed movement, rate
of travel, etc.). Oftentimes avoidance is
temporary, and animals return to the
area once the noise has ceased. Some
mysticetes may avoid larger activities as
they move through an area, although the
Navy’s activities do not typically use the
same training locations day-after-day
during multi-day activities, except
periodically in instrumented ranges,
which are not present in the GOA Study
Area. Therefore, displaced animals
could return quickly after even a large
activity or MTE is completed.
At most, only one MTE would occur
per year (over a maximum of 21 days),
and additionally, MF1 mid-frequency
active sonar would be prohibited from
June 1 to September 30 within the North
Pacific Right Whale Mitigation Area.
Explosives detonated below 10,000 ft.
altitude (including at the water surface)
would be prohibited in the Continental
Shelf and Slope Mitigation Area,
including in the portion that overlaps
the North Pacific Right Whale
Mitigation Area. In the open waters of
the Gulf of Alaska, the use of Navy
sonar and other active acoustic sources
is transient and would be unlikely to
expose the same population of animals
repeatedly over a short period of time,
especially given the broader-scale
movements of mysticetes and the 21-day
duration of the activities.
The implementation of procedural
mitigation and the sightability of
mysticetes (due to their large size)
would further reduce the potential for a
significant behavioral reaction or a
threshold shift to occur (i.e., shutdowns
are expected to be successfully
implemented), which is reflected in the
amount and type of incidental take that
would be anticipated to occur and is
proposed for authorization. Level B
harassment by behavioral disturbance of
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
mysticetes resulting from the TMAA
activities would likely be short-term and
of low to sometimes moderate severity,
with no anticipated effect on
reproduction or survival of any
individuals.
As noted previously, when an animal
incurs a threshold shift, it occurs in the
frequency from that of the source up to
one octave above. This means that the
vast majority of threshold shifts caused
by Navy sonar sources would typically
occur in the range of 2–20 kHz (from the
1–10 kHz MF bin, though in a specific
narrow band within this range as the
sources are narrowband), and if
resulting from hull-mounted sonar,
would be in the range of 3.5–7 kHz. The
majority of mysticete vocalizations
occur in frequencies below 1 kHz,
which means that TTS incurred by
mysticetes would not interfere with
conspecific communication.
Additionally, many of the other critical
sounds that serve as cues for navigation
and prey (e.g., waves, fish,
invertebrates) occur below a few kHz,
which means that detection of these
signals would not be inhibited by most
threshold shift either. When we look in
ocean areas where the Navy has been
intensively training and testing with
sonar and other active acoustic sources
for decades, there is no data suggesting
any long-term consequences to
reproduction or survival rates of
mysticetes from exposure to sonar and
other active acoustic sources.
All the mysticete species discussed in
this section would benefit from the
procedural mitigation measures
described earlier in the Proposed
Mitigation Measures section.
Additionally, the Navy would issue
awareness messages prior to the start of
TMAA training activities to alert vessels
and aircraft operating within the TMAA
to the possible presence of
concentrations of large whales,
including mysticetes, especially when
traversing on the continental shelf and
slope where densities of these species
may be higher. To maintain safety of
navigation and to avoid interactions
with marine mammals, the Navy would
instruct vessels to remain vigilant to the
presence of large whales that may be
vulnerable to vessel strikes or potential
impacts from training activities. Further,
the Navy would limit activities and
employ other measures in mitigation
areas that would avoid or reduce
impacts to mysticetes. Where these
mitigation areas are expected to mitigate
impacts to particular species or stocks
(North Pacific right whale, humpback
whale, gray whale), they are discussed
in detail below. Below we compile and
summarize the information that
PO 00000
Frm 00090
Fmt 4701
Sfmt 4702
supports our preliminary
determinations that the Navy’s activities
would not adversely affect any
mysticete species or stock through
effects on annual rates of recruitment or
survival.
North Pacific Right Whale (Eastern
North Pacific Stock)
North Pacific right whales are listed
as endangered under the ESA, and this
species is currently one of the most
endangered whales in the world
(Clapham, 2016; NMFS, 2013, 2017;
Wade et al., 2010). The current
population trend is unknown. ESAdesignated critical habitat for the North
Pacific right whale is located in the
western Gulf of Alaska off Kodiak Island
and in the southeastern Bering Sea/
Bristol Bay area (Muto et al., 2017; Muto
et al., 2018b; Muto et al., 2020a); there
is no designated critical habitat for this
species within the GOA Study Area.
North Pacific right whales are
anticipated to be present in the GOA
Study Area year round, but are
considered rare, with a potentially
higher density between June and
September. A BIA for feeding (June
through September; Ferguson et al.,
2015b) overlaps with the TMAA portion
of the GOA Study Area by
approximately 2,051 km2
(approximately 7 percent of the feeding
BIA and 1.4 percent of the TMAA). This
BIA does not overlap with any portion
of the WMA. This proposed rule
includes a North Pacific Right Whale
Mitigation Area and Continental Shelf
and Slope Mitigation Area, which both
overlap with the portion of the North
Pacific right whale feeding BIA that
overlaps with the TMAA. From June 1
to September 30, Navy personnel will
not use surface ship hull-mounted MF1
mid-frequency active sonar during
training activities within the North
Pacific Right Whale Mitigation Area.
Further, Navy personnel will not
detonate explosives below 10,000 ft
altitude (including at the water surface)
during training at all times in the
Continental Shelf and Slope Mitigation
Area (including in the portion that
overlaps the North Pacific Right Whale
Mitigation Area). These restrictions
would reduce the severity of impacts to
North Pacific right whales by reducing
interference in feeding that could result
in lost feeding opportunities or
necessitate additional energy
expenditure to find other good foraging
opportunities.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), only 3 instances of take by
level B harassment (2 TTS, and 1
behavioral disturbance) are estimated,
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
which equate to about 10 percent of the
very small estimated abundance. Given
this very small estimate, repeated
exposures of individuals are not
anticipated. Regarding the severity of
individual takes by Level B harassment
by behavioral disturbance, we have
explained that the duration of any
exposure is expected to be between
minutes and hours (i.e., relatively short)
and the received sound levels largely
below 172 dB with a small portion up
to 184 dB (i.e., of a moderate or
sometimes lower level). Regarding the
severity of TTS takes, they are expected
to be low-level, of short duration, and
mostly not in a frequency band that
would be expected to interfere with
North Pacific right whale
communication or other important lowfrequency cues. Therefore, the
associated lost opportunities and
capabilities are not at a level that would
impact reproduction or survival.
Altogether, North Pacific right whales
are listed as endangered under the ESA,
and the current population trend is
unknown. Only three instances of take
are estimated to occur (a small portion
of the stock), and any individual North
Pacific right whale is likely to be
disturbed at a low-moderate level. This
low magnitude and severity of
harassment effects is not expected to
result in impacts on the reproduction or
survival of any individuals, let alone
have impacts on annual rates of
recruitment or survival of this stock. No
mortality or Level A harassment is
anticipated or proposed to be
authorized. For these reasons, we have
preliminarily determined, in
consideration of all of the effects of the
Navy’s activities combined, that the
proposed authorized take would have a
negligible impact on the Eastern North
Pacific stock of North Pacific right
whales.
Humpback Whale (California/Oregon/
Washington Stock)
The California/Oregon/Washington
(CA/OR/WA) stock of humpback whales
includes individuals from three ESA
DPSs: Central America (endangered),
Mexico (threatened), and Hawaii (not
listed). A small portion of ESAdesignated critical habitat overlaps with
the TMAA portion of the GOA Study
Area (see Figure 4–1 of the Navy’s
rulemaking/LOA application). The ESAdesignated critical habitat does not
overlap with any portion of the WMA.
No other BIAs are identified for this
species in the GOA Study Area. The
SAR identifies this stock as stable
(having shown a long-term increase
from 1990 and then leveling off between
2008 and 2014). Navy personnel will
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
not use surface ship hull-mounted MF1
mid-frequency active sonar from June 1
to September 30 within the North
Pacific Right Whale Mitigation Area,
which overlaps 18 percent of the
humpback whale critical habitat in the
TMAA. Further, Navy personnel will
not detonate explosives below 10,000 ft
altitude (including at the water surface)
during training at all times in the
Continental Shelf and Slope Mitigation
Area (including in the portion that
overlaps the North Pacific Right Whale
Mitigation Area), which fully overlaps
the portion of the humpback whale
critical habitat in the TMAA. These
measures would reduce the severity of
impacts to humpback whales by
reducing interference in feeding that
could result in lost feeding
opportunities or necessitate additional
energy expenditure to find other good
opportunities.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), the number of estimated
total instances of take is 10 (8 TTS and
2 behavioral disturbance), which is less
than 1 percent of the abundance. Given
the very low number of anticipated
instances of take, only a very small
portion of individuals in the stock are
likely impacted and repeated exposures
of individuals are not anticipated.
Regarding the severity of those
individual takes by Level B harassment
by behavioral disturbance, we have
explained that the duration of any
exposure is expected to be between
minutes and hours (i.e., relatively short)
and the received sound levels largely
below 172 dB with a small portion up
to 184 dB (i.e., of a moderate or
sometimes lower level). Regarding the
severity of TTS takes, they are expected
to be low-level, of short duration, and
mostly not in a frequency band that
would be expected to interfere with
humpback whale communication or
other important low-frequency cues.
Therefore, the associated lost
opportunities and capabilities are not at
a level that would impact reproduction
or survival.
Altogether, this population is stable
(even though two of the three associated
DPSs are listed as endangered or
threatened under the ESA), only a very
small portion of the stock is anticipated
to be impacted, and any individual
humpback whale is likely to be
disturbed at a low-moderate level. No
mortality or serious injury and no Level
A harassment is anticipated or proposed
to be authorized. This low magnitude
and severity of harassment effects is not
expected to result in impacts on the
reproduction or survival of any
individuals, let alone have impacts on
PO 00000
Frm 00091
Fmt 4701
Sfmt 4702
49745
annual rates of recruitment or survival
of this stock. For these reasons, we have
preliminarily determined, in
consideration of all of the effects of the
Navy’s activities combined, that the
proposed authorized take would have a
negligible impact on the CA/OR/WA
stock of humpback whales.
Humpback Whale (Central North Pacific
Stock)
The Central North Pacific stock of
humpback whales consists of winter/
spring humpback whale populations of
the Hawaiian Islands which migrate
primarily to foraging habitat in northern
British Columbia/Southeast Alaska, the
Gulf of Alaska, and the Bering Sea/
Aleutian Islands. The population is
increasing (Muto et al. 2020), the Hawaii
DPS is not ESA-listed, and no BIAs have
been identified for this species in the
GOA Study Area. Navy personnel will
not use surface ship hull-mounted MF1
mid-frequency active sonar from June 1
to September 30 within the North
Pacific Right Whale Mitigation Area,
which overlaps 18 percent of the
humpback whale critical habitat within
the TMAA. As noted above, the Hawaii
DPS is not ESA-listed; however, this
ESA-designated critical habitat still
indicates the likely value of habitat in
this area to non-listed humpback
whales. Further, Navy personnel will
not detonate explosives below 10,000 ft
altitude (including at the water surface)
during training at all times in the
Continental Shelf and Slope Mitigation
Area (including in the portion that
overlaps the North Pacific Right Whale
Mitigation Area), which fully overlaps
the portion of the humpback whale
critical habitat in the TMAA. These
measures would reduce the severity of
impacts to humpback whales by
reducing interference in feeding that
could result in lost feeding
opportunities or necessitate additional
energy expenditure to find other good
opportunities.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), the number of estimated
instances of take compared to the
abundance is less than 1 percent. This
information and the complicated farranging nature of the stock structure
indicates that only a very small portion
of the stock is likely impacted. While no
BIAs have been identified in the GOA
Study Area, highest densities in the
nearby Kodiak Island feeding BIA (July
to September) and Prince William
Sound feeding BIA (September to
December) overlap with much of the
potential window for the Navy’s
exercise in the GOA Study Area (April
to October). Given that some whales
E:\FR\FM\11AUP2.SGM
11AUP2
49746
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
may remain in the area surrounding
these BIAs for some time to feed during
the Navy’s exercise, there may be a few
repeated exposures of a few individuals,
most likely on non-sequential days.
Regarding the severity of those
individual takes by Level B harassment
by behavioral disturbance, we have
explained that the duration of any
exposure is expected to be between
minutes and hours (i.e., relatively short)
and the received sound levels largely
below 172 dB with a small portion up
to 184 dB (i.e., of a moderate or
sometimes lower level). Regarding the
severity of TTS takes, they are expected
to be low-level, of short duration, and
mostly not in a frequency band that
would be expected to interfere with
humpback whale communication or
other important low-frequency cues.
Therefore, the associated lost
opportunities and capabilities are not at
a level that would impact reproduction
or survival.
Altogether, this population is
increasing and the associated DPS is not
listed as endangered or threatened
under the ESA. Only a very small
portion of the stock is anticipated to be
impacted and any individual humpback
whale is likely to be disturbed at a lowmoderate level. This low magnitude and
severity of harassment effects is not
expected to result in impacts on
individual reproduction or survival, let
alone have impacts on annual rates of
recruitment or survival of this stock. No
mortality or Level A harassment is
anticipated or proposed to be
authorized. For these reasons, we have
preliminarily determined, in
consideration of all of the effects of the
Navy’s activities combined, that the
proposed authorized take would have a
negligible impact on the Central North
Pacific stock of humpback whales.
Humpback Whale (Western North
Pacific Stock)
The Western North Pacific stock of
humpback whales includes individuals
from the Western North Pacific DPS,
which is ESA-listed as endangered. A
relatively small portion of ESAdesignated critical habitat overlaps with
the TMAA (2,708 km2 (1,046 mi2) of
critical habitat Unit 5, 5,991 km2 (2,313
mi2) of critical habitat Unit 8; see Figure
4–1 of the Navy’s rulemaking/LOA
application). The ESA-designated
critical habitat does not overlap with
any portion of the WMA. No other BIAs
are identified for this species in the
GOA Study Area. The current
population trend for this stock is
unknown. Navy personnel will not use
surface ship hull-mounted MF1 midfrequency active sonar from June 1 to
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
September 30 within the North Pacific
Right Whale Mitigation Area, which
overlaps 18 percent of the humpback
whale critical habitat within the TMAA.
Further, Navy personnel will not
detonate explosives below 10,000 ft
altitude (including at the water surface)
during training at all times in the
Continental Shelf and Slope Mitigation
Area (including in the portion that
overlaps the North Pacific Right Whale
Mitigation Area), which fully overlaps
the portion of the humpback whale
critical habitat in the TMAA. These
measures would reduce the severity of
impacts to humpback whales by
reducing interference in feeding that
could result in lost feeding
opportunities or necessitate additional
energy expenditure to find other good
opportunities.
Regarding the magnitude of takes by
Level B harassment (behavioral
disturbance only), the number of
estimated total instances of take is three,
which is less than 1 percent of the
abundance. Given the very low number
of anticipated instances of take, only a
very small portion of individuals in the
stock are likely impacted and repeated
exposures of individuals are not
anticipated. Regarding the severity of
those individual takes by Level B
harassment by behavioral disturbance,
we have explained that the duration of
any exposure is expected to be between
minutes and hours (i.e., relatively short)
and the received sound levels largely
below 172 dB with a small portion up
to 184 dB (i.e., of a moderate or
sometimes lower level).
Altogether, the status of this stock is
unknown, only a very small portion of
the stock is anticipated to be impacted
(3 individuals), and any individual
humpback whale is likely to be
disturbed at a low-moderate level. No
mortality, serious injury, Level A
harassment, or TTS is anticipated or
proposed to be authorized. This low
magnitude and severity of harassment
effects is not expected to result in
impacts on the reproduction or survival
of any individuals, let alone have
impacts on annual rates of recruitment
or survival of this stock. For these
reasons, we have preliminarily
determined, in consideration of all of
the effects of the Navy’s activities
combined, that the proposed authorized
take would have a negligible impact on
the Western North Pacific stock of
humpback whales.
Blue Whale (Central North Pacific Stock
and Eastern North Pacific Stock)
Blue whales are listed as endangered
under the ESA throughout their range,
but there is no ESA designated critical
PO 00000
Frm 00092
Fmt 4701
Sfmt 4702
habitat and no BIAs have been
identified for this species in the GOA
Study Area. The current population
trend for the Central North Pacific stock
is unknown, and the Eastern North
Pacific stock is stable.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), the number of estimated
total instances of take compared to the
abundance is 2 percent for both the
Central North Pacific stock, and the
Eastern North Pacific stock. For the
Central North Pacific stock, only 3
instances of take (TTS) are anticipated.
Given the range of both blue whale
stocks, the absence of any known
feeding or aggregation areas, and the
very low number of anticipated
instances of take of the Central North
Pacific stock, this information indicates
that only a small portion of individuals
in the stock are likely impacted and
repeated exposures of individuals are
not anticipated. Regarding the severity
of those individual takes by Level B
harassment by behavioral disturbance,
we have explained that the duration of
any exposure is expected to be between
minutes and hours (i.e., relatively short)
and the received sound levels largely
below 172 dB with a small portion up
to 184 dB (i.e., of a moderate or
sometimes lower level). Regarding the
severity of TTS takes, we have
explained that they are expected to be
low-level, of short duration, and mostly
not in a frequency band that would be
expected to interfere with blue whale
communication or other important lowfrequency cues. Therefore, the
associated lost opportunities and
capabilities are not at a level that would
impact reproduction or survival.
Altogether, blue whales are listed as
endangered under the ESA throughout
their range, the current population trend
for the Central North Pacific stock is
unknown, and the Eastern North Pacific
stock is stable. Only a small portion of
the stocks are anticipated to be
impacted, and any individual blue
whale is likely to be disturbed at a lowmoderate level. The low magnitude and
severity of harassment effects is not
expected to result in impacts on the
reproduction or survival of any
individuals, let alone have impacts on
annual rates of recruitment or survival
of this stock. No mortality and no Level
A harassment is anticipated or proposed
for authorization. For these reasons, we
have preliminarily determined, in
consideration of all of the effects of the
Navy’s activities combined, that the
proposed authorized take would have a
negligible impact on the Central North
Pacific stock and the Eastern North
Pacific stock of blue whales.
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
Fin Whale (Northeast Pacific Stock)
Fin whales are listed as endangered
under the ESA throughout their range,
but there is no ESA designated critical
habitat and no BIAs have been
identified for this species in the GOA
Study Area. The SAR identifies this
stock as increasing.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), the number of estimated
total instances of take compared to the
abundance is 39 percent (though, as
noted in Table 41, the SAR reports the
stock abundance assessment as
provisional and notes that it is an
underestimate for the entire stock
because it is based on surveys which
covered only a small portion of the
stock’s range, and therefore 39 percent
is likely an overestimate). Given the
large range of the stock and short
duration of the Navy’s activities in the
GOA Study Area, this information
suggests that notably fewer than half of
the individuals of the stock would likely
be impacted, and that most affected
individuals would likely be disturbed
on a few days within the 21-day
exercise, with the days most likely being
non-sequential. Regarding the severity
of those individual takes by Level B
harassment by behavioral disturbance,
we have explained that the duration of
any exposure is expected to be between
minutes and hours (i.e., relatively short)
and the received sound levels largely
below 172 dB with a small portion up
to 184 dB (i.e., of a moderate or
sometimes lower level). Regarding the
severity of TTS takes, they are expected
to be low-level, of short duration, and
mostly not in a frequency band that
would be expected to interfere with fin
whale communication or other
important low-frequency cues.
Therefore, the associated lost
opportunities and capabilities are not at
a level that would impact reproduction
or survival.
For these same reasons (low level and
frequency band), while a small
permanent loss of hearing sensitivity
(PTS) may include some degree of
energetic costs for compensating or may
mean some small loss of opportunities
or detection capabilities, at the expected
scale the estimated two takes by Level
A harassment by PTS would be unlikely
to impact behaviors, opportunities, or
detection capabilities to a degree that
would interfere with reproductive
success or survival of those individuals.
Thus, the two takes by Level A
harassment by PTS would be unlikely to
affect rates of recruitment and survival
for the stock.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
Altogether, fin whales are listed as
endangered under the ESA, though this
population is increasing. Only a small
portion of the stock is anticipated to be
impacted, and any individual fin whale
is likely to be disturbed at a lowmoderate level. This low magnitude and
severity of harassment effects is not
expected to result in impacts on
reproduction or survival of any
individuals, let alone have impacts on
annual rates of recruitment or survival
of this stock. No mortality or serious
injury and no Level A harassment from
non-auditory tissue damage is
anticipated or proposed for
authorization. For these reasons, we
have preliminarily determined, in
consideration of all of the effects of the
Navy’s activities combined, that the
proposed authorized take would have a
negligible impact on the Northeast
Pacific stock of fin whales.
Sei Whale (Eastern North Pacific Stock)
The population trend of this stock is
unknown, however sei whales are listed
as endangered under the ESA
throughout their range. There is no ESA
designated critical habitat and no BIAs
have been identified for this species in
the GOA Study Area.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), the number of estimated
total instances of take compared to the
abundance is 7 percent. This
information and the rare occurrence of
sei whales in the TMAA suggests that
only a small portion of individuals in
the stock would likely be impacted and
repeated exposures of individuals
would not be anticipated. Regarding the
severity of those individual takes by
Level B harassment by behavioral
disturbance, we have explained that the
duration of any exposure is expected to
be between minutes and hours (i.e.,
relatively short) and the received sound
levels largely below 172 dB with a small
portion up to 184 dB (i.e., of a moderate
or sometimes lower level). Regarding
the severity of TTS takes, they are
expected to be low-level, of short
duration, and mostly not in a frequency
band that would be expected to interfere
with sei whale communication or other
important low-frequency cues.
Therefore, the associated lost
opportunities and capabilities are not at
a level that would impact reproduction
or survival.
Altogether, the status of the stock is
unknown and the species is listed as
endangered, only a small portion of the
stock is anticipated to be impacted, and
any individual sei whale is likely to be
disturbed at a low-moderate level. This
low magnitude and severity of
PO 00000
Frm 00093
Fmt 4701
Sfmt 4702
49747
harassment effects is not expected to
result in impacts on individual
reproduction or survival, much less
annual rates of recruitment or survival.
No mortality and no Level A harassment
is anticipated or proposed for
authorization. For these reasons, we
have preliminarily determined, in
consideration of all of the effects of the
Navy’s activities combined, that the
proposed authorized take would have a
negligible impact on the Eastern North
Pacific stock of sei whales.
Minke Whale (Alaska Stock)
The status of this stock is unknown
and the species is not listed under the
ESA. No BIAs have been identified for
this species in the GOA Study Area.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), the number of estimated
total instances of take compared to the
abundance is 13 percent for the Alaska
stock (based on, to be conservative, the
smallest available provisional estimate
in the SAR, which is derived from
surveys that cover only a portion of the
stock’s range). Given the range of the
Alaska stock of minke whales, this
information indicates that only a small
portion of individuals in this stock are
likely to be impacted and repeated
exposures of individuals are not
anticipated. Regarding the severity of
those individual takes by Level B
harassment by behavioral disturbance,
we have explained that the duration of
any exposure is expected to be between
minutes and hours (i.e., relatively short)
and the received sound levels largely
below 172 dB with a small portion up
to 184 dB (i.e., of a moderate or
sometimes lower level). Regarding the
severity of TTS takes, they are expected
to be low-level, of short duration, and
mostly not in a frequency band that
would be expected to interfere with
minke whale communication or other
important low-frequency cues.
Therefore, the associated lost
opportunities and capabilities are not at
a level that would impact reproduction
or survival.
Altogether, although the status of the
stock is unknown, the species is not
listed under the ESA as endangered or
threatened, only a small portion of the
stock is anticipated to be impacted, and
any individual minke whale is likely to
be disturbed at a low-moderate level.
This low magnitude and severity of
harassment effects is not expected to
result in impacts on individual
reproduction or survival, let alone have
impacts on annual rates of recruitment
or survival of this stock. No mortality,
serious injury, or Level A harassment is
anticipated or proposed to be
E:\FR\FM\11AUP2.SGM
11AUP2
49748
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
authorized. For these reasons, we have
preliminarily determined, in
consideration of all of the effects of the
Navy’s activities combined, that the
proposed authorized take would have a
negligible impact on the Alaska stock of
minke whales.
lotter on DSK11XQN23PROD with PROPOSALS2
Gray Whale (Eastern North Pacific
Stock)
The Eastern North Pacific stock of
gray whale is not ESA-listed, and the
SAR indicates that the stock is
increasing. The TMAA portion of the
GOA Study Area overlaps with a gray
whale migration corridor that has been
identified as a BIA (November–January
(outside of the potential training
window), southbound; March–May,
northbound; Ferguson et al., 2015). The
WMA portion of the GOA Study Area
does not overlap with any known
important areas for gray whales.
Regarding the magnitude of takes by
Level B harassment (behavioral
disturbance only), the number of
estimated total instances of take is four,
which is less than 1 percent of the
abundance. Given the very low number
of anticipated instances of take, only a
very small portion of individuals in the
stock are likely impacted and repeated
exposures of individuals are not
anticipated. Regarding the severity of
those individual takes by Level B
harassment by behavioral disturbance,
we have explained that the duration of
any exposure is expected to be between
minutes and hours (i.e., relatively short)
and the received sound levels largely
below 172 dB with a small portion up
to 184 dB (i.e., of a moderate or
sometimes lower level).
Altogether, while we have considered
the impacts of the gray whale UME, this
population of gray whales is not
endangered or threatened under the
ESA, and the stock is increasing. No
mortality, Level A harassment, or TTS is
anticipated or proposed to be
authorized. Only a very small portion of
the stock is anticipated to be impacted,
and any individual gray whale is likely
to be disturbed at a low-moderate level.
This low magnitude and severity of
harassment effects is not expected to
result in impacts on the reproduction or
survival of any individuals, let alone
have impacts on annual rates of
recruitment or survival of this stock. For
these reasons, we have preliminarily
determined, in consideration of all of
the effects of the Navy’s activities
combined, that the proposed authorized
take would have a negligible impact on
the Eastern North Pacific stock of gray
whales.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
Odontocetes
This section builds on the broader
discussion above and brings together the
discussion of the different types and
amounts of take that different species
and stocks would likely incur, the
applicable mitigation, and the status of
the species and stocks to support the
negligible impact determinations for
each species or stock. We have
described (earlier in this section) the
unlikelihood of any masking having
effects that would impact the
reproduction or survival of any of the
individual marine mammals affected by
the Navy’s activities. We have also
described above in the Potential Effects
of Specified Activities on Marine
Mammals and their Habitat section the
unlikelihood of any habitat impacts
having effects that would impact the
reproduction or survival of any of the
individual marine mammals affected by
the Navy’s activities. There is no
predicted PTS from sonar or explosives
for most odontocetes, with the
exception of Dall’s porpoise, which is
discussed below. There is no
anticipated M/SI or non-auditory tissue
damage from sonar or explosives for any
species. Here, we include information
that applies to all of the odontocete
species, which are then further divided
and discussed in more detail in the
following subsections: sperm whales;
beaked whales; dolphins and small
whales; and porpoises. These
subsections include more specific
information about the groups, as well as
conclusions for each species or stock
represented.
The majority of takes by harassment
of odontocetes in the TMAA are caused
by sources from the MFAS bin (which
includes hull-mounted sonar) because
they are high level, typically
narrowband sources at a frequency (in
the 1–10 kHz range) that overlaps a
more sensitive portion (though not the
most sensitive) of the MF hearing range
and they are used in a large portion of
exercises (see Table 1 and Table 3). For
odontocetes other than beaked whales
(for which these percentages are
indicated separately in that section),
most of the takes (95 percent) from the
MF1 bin in the TMAA would result
from received levels between 160 and
172 dB SPL. For the remaining active
sonar bin types, the percentages are as
follows: MF4 = 98 percent between 142
and 160 dB SPL and MF5 = 94 percent
between 118 and 142 dB SPL. Based on
this information, the majority of the
takes by Level B harassment by
behavioral disturbance are expected to
be low to sometimes moderate in nature,
but still of a generally shorter duration.
PO 00000
Frm 00094
Fmt 4701
Sfmt 4702
For all odontocetes, takes from
explosives (Level B harassment by
behavioral disturbance, TTS, or PTS)
comprise a very small fraction (and low
number) of those caused by exposure to
active sonar. For the following
odontocetes, zero takes from explosives
are expected to occur: sperm whale,
killer whale, Pacific white-sided
dolphin, Baird’s beaked whale, and
Stejneger’s beaked whale. For Level B
harassment by behavioral disturbance
from explosives, one take is anticipated
for Cuvier’s beaked whale and 38 takes
are anticipated for Dall’s porpoise. No
TTS or PTS is expected to occur from
explosives for any stocks except Dall’s
porpoise. Because of the lower TTS and
PTS thresholds for HF odontocetes, the
Alaska stock of Dall’s porpoise is
expected to have 229 takes by TTS and
45 takes by PTS from explosives.
Because the majority of harassment
takes of odontocetes result from the
sources in the MFAS bin, the vast
majority of threshold shift would occur
at a single frequency within the 1–10
kHz range and, therefore, the vast
majority of threshold shift caused by
Navy sonar sources would be at a single
frequency within the range of 2–20 kHz.
The frequency range within which any
of the anticipated narrowband threshold
shift would occur would fall directly
within the range of most odontocete
vocalizations (2–20 kHz) (though
phocoenids generally communicate at
higher frequencies (Soerensen et al.,
2018; Clausen et al. 2010), which would
not be impacted by this threshold shift).
For example, the most commonly used
hull-mounted sonar has a frequency
around 3.5 kHz, and any associated
threshold shift would be expected to be
at around 7 kHz. However, odontocete
vocalizations typically span a much
wider range than this, and alternately,
threshold shift from active sonar will
often be in a narrower band (reflecting
the narrower band source that caused
it), which means that TTS incurred by
odontocetes would typically only
interfere with communication within a
portion of their hearing range (if it
occurred during a time when
communication with conspecifics was
occurring) and, as discussed earlier, it
would only be expected to be of a short
duration and relatively small degree.
Odontocete echolocation occurs
predominantly at frequencies
significantly higher than 20 kHz (though
there may be some small overlap at the
lower part of their echolocating range
for some species), which means that
there is little likelihood that threshold
shift, either temporary or permanent,
would interfere with feeding behaviors.
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
Many of the other critical sounds that
serve as cues for navigation and prey
(e.g., waves, fish, invertebrates) occur
below a few kHz, which means that
detection of these signals will not be
inhibited by most threshold shift either.
The low number of takes by threshold
shift that might be incurred by
individuals exposed to explosives
would likely be lower frequency (5 kHz
or less) and spanning a wider frequency
range, which could slightly lower an
individual’s sensitivity to navigational
or prey cues, or a small portion of
communication calls, for several
minutes to hours (if temporary) or
permanently. There is no reason to
think that the vast majority of the
individual odontocetes taken by TTS
would incur TTS on more than one day,
although a small number could incur
TTS on a few days at most. Therefore,
odontocetes are unlikely to incur
impacts on reproduction or survival as
a result of TTS. PTS takes from these
sources are very low (0 for all species
other than Dall’s porpoise), and while
spanning a wider frequency band, are
still expected to be of a low degree (i.e.,
low amount of hearing sensitivity loss)
and unlikely to affect reproduction or
survival.
The range of potential behavioral
effects of sound exposure on marine
mammals generally, and odontocetes
specifically, has been discussed in
detail previously. There are behavioral
patterns that differentiate the likely
impacts on odontocetes as compared to
mysticetes however. First, odontocetes
echolocate to find prey, which means
that they actively send out sounds to
detect their prey. While there are many
strategies for hunting, one common
pattern, especially for deeper diving
species, is many repeated deep dives
within a bout, and multiple bouts
within a day, to find and catch prey. As
discussed above, studies demonstrate
that odontocetes may cease their
foraging dives in response to sound
exposure. If enough foraging
interruptions occur over multiple
sequential days, and the individual
either does not take in the necessary
food, or must exert significant effort to
find necessary food elsewhere, energy
budget deficits can occur that could
potentially result in impacts to
reproductive success, such as increased
cow/calf intervals (the time between
successive calving). However, the
relatively low impact of the Navy’s
activities on odontocetes in the TMAA
indicate this is not likely to occur.
Second, while many mysticetes rely on
seasonal migratory patterns that
position them in a geographic location
at a specific time of the year to take
advantage of ephemeral large
abundances of prey (i.e., invertebrates or
small fish, which they eat by the
thousands), odontocetes forage more
homogeneously on one fish or squid at
a time. Therefore, if odontocetes are
interrupted while feeding, it is often
possible to find more prey relatively
nearby.
49749
All the odontocete species and stocks
discussed in this section would benefit
from the procedural mitigation
measures described earlier in the
Proposed Mitigation Measures section.
Sperm Whale (North Pacific Stock)
This section builds on the broader
odontocete discussion above and brings
together the discussion of the different
types and amounts of take that sperm
whales would likely incur, the
applicable mitigation, and the status of
the species/stock to support the
preliminary negligible impact
determination for the stock.
Sperm whales are listed as
endangered under the ESA. No critical
habitat has been designated for sperm
whales under the ESA and no BIAs for
sperm whales have been identified in
the GOA Study Area. The stock’s
current population trend is unknown.
The Navy would issue awareness
messages prior to the start of TMAA
training activities to alert Navy ships
and aircraft operating within the TMAA
to the possible presence of increased
concentrations of large whales,
including sperm whales. This measure
would further reduce any possibility of
ship strike of sperm whales.
In Table 42 below for sperm whales,
we indicate the total annual numbers of
take by Level A harassment and Level
B harassment, and a number indicating
the instances of total take as a
percentage of abundance.
TABLE 42—ANNUAL ESTIMATED TAKES BY LEVEL B HARASSMENT AND LEVEL A HARASSMENT FOR SPERM WHALES IN
THE TMAA AND NUMBER INDICATING THE INSTANCES OF TOTAL TAKE AS A PERCENTAGE OF SPECIES/STOCK ABUNDANCE
Instances of indicated types of incidental take1
Level B harassment
Species
Stock
Behavioral
disturbance
Sperm whale .........
North Pacific .........
TTS
(may also
include
disturbance)
107
Level A
harassment
5
Total takes
Abundance
(NMFS
SARs)2
Instances of
total take
as percentage
of abundance
112
3 345
32.5
PTS
0
1 Estimated
lotter on DSK11XQN23PROD with PROPOSALS2
impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate individuals, especially for disturbance.
2 Presented in the 2021 draft SARs or most recent SAR.
3 The SAR reports that this is an underestimate for the entire stock because it is based on surveys of a small portion of the stock’s extensive
range and it does not account for animals missed on the trackline or for females and juveniles in tropical and subtropical waters.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), the number of estimated
total instances of take compared to the
abundance is 33 percent. Given the
range of this stock, this information
indicates that fewer than half of the
individuals in the stock are likely to be
impacted, with those individuals
disturbed on likely one, but not more
than a few non-sequential days within
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
the 21 days per year. Additionally,
while interrupted feeding bouts are a
known response and concern for
odontocetes, we also know that there are
often viable alternative habitat options
in the relative vicinity. Regarding the
severity of those individual takes by
Level B harassment by behavioral
disturbance, we have explained that the
duration of any exposure is expected to
be between minutes and hours (i.e.,
PO 00000
Frm 00095
Fmt 4701
Sfmt 4702
relatively short) and the received sound
levels largely below 172 dB (i.e., of a
lower, to occasionally moderate, level
and less likely to evoke a severe
response). As discussed earlier in the
Preliminary Analysis and Negligible
Impact Determination section, we
anticipate more severe effects from takes
when animals are exposed to higher
received levels or for longer durations.
Occasional milder Level B harassment
E:\FR\FM\11AUP2.SGM
11AUP2
49750
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
by behavioral disturbance, as is
expected here, is unlikely to cause longterm consequences for either individual
animals or populations, even if some
smaller subset of the takes are in the
form of a longer (several hours or a day)
and more moderate response. Regarding
the severity of TTS takes, they are
expected to be low-level, of short
duration, and mostly not in a frequency
band that would be expected to interfere
with sperm whale communication or
other important low-frequency cues.
Therefore, the associated lost
opportunities and capabilities are not at
a level that would impact reproduction
or survival.
Altogether, sperm whales are listed as
endangered under the ESA, and the
current population trend is unknown.
Fewer than half of the individuals of the
stock are anticipated to be impacted,
and any individual sperm whale is
likely to be disturbed at a low-moderate
level. This low magnitude and severity
of harassment effects is not expected to
result in impacts on reproduction or
survival for any individuals, let alone
have impacts on annual rates of
recruitment or survival of this stock. No
mortality, serious injury, or Level A
harassment is anticipated or proposed to
be authorized. For these reasons, we
have preliminarily determined, in
consideration of all of the effects of the
Navy’s activities combined, that the
proposed authorized take would have a
negligible impact on the North Pacific
stock of sperm whales.
Beaked Whales
This section builds on the broader
odontocete discussion above and brings
together the discussion of the different
types and amounts of take that different
beaked whale species and stocks would
likely incur, the applicable mitigation,
and the status of the species and stocks
to support the preliminary negligible
impact determinations for each species
or stock. For beaked whales, no
mortality or Level A harassment is
anticipated or proposed for
authorization.
In Table 43 below for beaked whales,
we indicate the total annual numbers of
take by Level A harassment and Level
B harassment, and a number indicating
the instances of total take as a
percentage of abundance.
TABLE 43—ANNUAL ESTIMATED TAKES BY LEVEL B HARASSMENT AND LEVEL A HARASSMENT FOR BEAKED WHALES IN
THE TMAA AND NUMBER INDICATING THE INSTANCES OF TOTAL TAKE AS A PERCENTAGE OF SPECIES/STOCK ABUNDANCE
Instances of indicated types of incidental take1
Level B harassment
Species
Stock
Behavioral
disturbance
Baird’s beaked whale ............
Cuvier’s beaked whale ..........
Stejneger’s beaked whale .....
Alaska ....................................
Alaska ....................................
Alaska ....................................
106
430
467
Level A
harassment
TTS
(may also
include
disturbance)
Total takes
Abundance
(NMFS
SARs)2
Instances of
total take as
percentage
of abundance
PTS
0
3
15
0
0
0
106
433
482
NA
NA
NA
NA
NA
NA
lotter on DSK11XQN23PROD with PROPOSALS2
1 Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate individuals, especially for disturbance.
2 Reliable estimates of abundance for these stocks are currently unavailable.
This first paragraph provides specific
information that is in lieu of the parallel
information provided for odontocetes as
a whole. The majority of takes by
harassment of beaked whales in the
TMAA would be caused by sources
from the MFAS bin (which includes
hull-mounted sonar) because they are
high level narrowband sources that fall
within the 1–10 kHz range, which
overlap a more sensitive portion (though
not the most sensitive) of the MF
hearing range. Also, of the sources
expected to result in take, they are used
in a large portion of exercises (see Table
1 and Table 3). Most of the takes (98
percent) from the MF1 bin in the TMAA
would result from received levels
between 148 and 166 dB SPL. For the
remaining active sonar bin types, the
percentages are as follows: MF4 = 97
percent between 130 and 148 dB SPL
and MF5 = 99 percent between 100 and
148 dB SPL. Given the levels they are
exposed to and beaked whale
sensitivity, some responses would be of
a lower severity, but many would likely
be considered moderate, but still of
generally short duration.
Research has shown that beaked
whales are especially sensitive to the
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
presence of human activity (Pirotta et
al., 2012; Tyack et al., 2011) and
therefore have been assigned a lower
harassment threshold, with lower
received levels resulting in a higher
percentage of individuals being
harassed and a more distant distance
cutoff (50 km for high source level, 25
km for moderate source level).
Beaked whales have been
documented to exhibit avoidance of
human activity or respond to vessel
presence (Pirotta et al., 2012). Beaked
whales were observed to react
negatively to survey vessels or low
altitude aircraft by quick diving and
other avoidance maneuvers, and none
were observed to approach vessels
(Wursig et al., 1998). Available
information suggests that beaked whales
likely have enhanced sensitivity to
sonar sound, given documented
incidents of stranding in conjunction
with specific circumstances of MFAS
use, although few definitive causal
relationships between MFAS use and
strandings have been documented (see
Potential Effects of Specified Activities
on Marine Mammals and their Habitat
section). NMFS neither anticipates nor
proposes to authorize the mortality of
PO 00000
Frm 00096
Fmt 4701
Sfmt 4702
beaked whales (or any other species or
stocks) resulting from exposure to active
sonar.
Research and observations show that
if beaked whales are exposed to sonar or
other active acoustic sources, they may
startle, break off feeding dives, and
avoid the area of the sound source to
levels of 157 dB re: 1 mPa, or below
(McCarthy et al., 2011). For example,
after being exposed to 1–2 kHz upsweep
naval sonar signals at a received SPL of
107 dB re 1 mPa, Northern bottlenose
whales began moving in an unusually
straight course, made a near 180° turn
away from the source, and performed
the longest and deepest dive (94 min,
2339 m) recorded for this species (Miller
et al., 2015). Wensveen et al. (2019) also
documented avoidance behaviors in
Northern bottlenose whales exposed to
1–2 kHz tonal sonar signals with SPLs
ranging between 117–126 dB re: 1 mPa,
including interrupted diving behaviors,
elevated swim speeds, directed
movements away from the sound
source, and cessation of acoustic signals
throughout exposure periods. Acoustic
monitoring during actual sonar
exercises revealed some beaked whales
continuing to forage at levels up to 157
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
dB re: 1 mPa (Tyack et al., 2011).
Stimpert et al. (2014) tagged a Baird’s
beaked whale, which was subsequently
exposed to simulated MFAS. Changes in
the animal’s dive behavior and
locomotion were observed when
received level reached 127 dB re: 1 mPa.
However, Manzano-Roth et al. (2013)
found that for beaked whale dives that
continued to occur during MFAS
activity, differences from normal dive
profiles and click rates were not
detected with estimated received levels
up to 137 dB re: 1 mPa while the animals
were at depth during their dives. In
research done at the Navy’s fixed
tracking range in the Bahamas, animals
were observed to leave the immediate
area of the anti-submarine warfare
training exercise (avoiding the sonar
acoustic footprint at a distance where
the received level was ‘‘around 140 dB
SPL,’’ according to Tyack et al. (2011)),
but return within a few days after the
event ended (Claridge and Durban,
2009; McCarthy et al., 2011; Moretti et
al., 2009, 2010; Tyack et al., 2010,
2011). Joyce et al. (2019) found that
Blainville’s beaked whales moved up to
68 km away from an Atlantic Undersea
Test and Evaluation Center site and
reduced time spent on deep dives after
the onset of mid-frequency active sonar
exposure; whales did not return to the
site until 2–4 days after the exercises
ended. Changes in acoustic activity have
also been documented. For example,
Blainville’s beaked whales showed
decreased group vocal periods after
biannual multi-day Navy training
activities (Henderson et al., 2016).
Tyack et al. (2011) reported that, in
reaction to sonar playbacks, most
beaked whales stopped echolocating,
made long slow ascent to the surface,
and moved away from the sound. A
similar behavioral response study
conducted in Southern California waters
during the 2010–2011 field season
found that Cuvier’s beaked whales
exposed to MFAS displayed behavior
ranging from initial orientation changes
to avoidance responses characterized by
energetic fluking and swimming away
from the source (DeRuiter et al., 2013b).
However, the authors did not detect
similar responses to incidental exposure
to distant naval sonar exercises at
comparable received levels, indicating
that context of the exposures (e.g.,
source proximity, controlled source
ramp-up) may have been a significant
factor. The study itself found the results
inconclusive and meriting further
investigation. Falcone et al. (2017)
however, documented that Cuvier’s
beaked whales had longer dives and
surface durations after exposure to mid-
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
frequency active sonar, with the longer
surface intervals contributing to a longer
interval between deep dives, a proxy for
foraging disruption in this species.
Cuvier’s beaked whale responses
suggested particular sensitivity to sound
exposure consistent with results for
Blainville’s beaked whale.
Populations of beaked whales and
other odontocetes on the Bahamas and
other Navy fixed ranges that have been
operating for decades appear to be
stable. Behavioral reactions (avoidance
of the area of Navy activity) seem most
likely in cases where beaked whales are
exposed to anti-submarine sonar within
a few tens of kilometers, especially for
prolonged periods (a few hours or more)
since this is one of the most sensitive
marine mammal groups to
anthropogenic sound of any species or
group studied to date and research
indicates beaked whales will leave an
area where anthropogenic sound is
present (De Ruiter et al., 2013;
Manzano-Roth et al., 2013; Moretti et
al., 2014; Tyack et al., 2011). Research
involving tagged Cuvier’s beaked whales
in the SOCAL Range Complex reported
on by Falcone and Schorr (2012, 2014)
indicates year-round prolonged use of
the Navy’s training and testing area by
these beaked whales and has
documented movements in excess of
hundreds of kilometers by some of those
animals. Given that some of these
animals may routinely move hundreds
of kilometers as part of their normal
pattern, leaving an area where sonar or
other anthropogenic sound is present
may have little, if any, cost to such an
animal. Photo identification studies in
the SOCAL Range Complex, a Navy
range that is utilized for training and
testing, have identified approximately
100 Cuvier’s beaked whale individuals
with 40 percent having been seen in one
or more prior years, with re-sightings up
to 7 years apart (Falcone and Schorr,
2014). These results indicate long-term
residency by individuals in an
intensively used Navy training and
testing area, which may also suggest a
lack of long-term consequences as a
result of exposure to Navy training and
testing activities. More than 8 years of
passive acoustic monitoring on the
Navy’s instrumented range west of San
Clemente Island documented no
significant changes in annual and
monthly beaked whale echolocation
clicks, with the exception of repeated
fall declines likely driven by natural
beaked whale life history functions
(DiMarzio et al., 2018). Finally, results
from passive acoustic monitoring
estimated that regional Cuvier’s beaked
whale densities were higher than
PO 00000
Frm 00097
Fmt 4701
Sfmt 4702
49751
indicated by NMFS’ broad scale visual
surveys for the United States West Coast
(Hildebrand and McDonald, 2009).
Below we compile and summarize the
information that supports our
preliminary determinations that the
Navy’s activities would not adversely
affect any of the beaked whale stocks
through effects on annual rates of
recruitment or survival. Baird’s,
Cuvier’s, and Stejneger’s beaked whales
(Alaska stocks)
Baird’s beaked whale, Cuvier’s beaked
whale, and Stejneger’s beaked whale are
not listed as endangered or threatened
species under the ESA, and the 2019
Alaska SARs indicate that trend
information is not available for any of
the Alaska stocks. No BIAs for beaked
whales have been identified in the GOA
Study Area.
As indicated in Table 43, no
abundance estimates are available for
any of the stocks. However, the ranges
of all three stocks are large compared to
the GOA Study Area (Cuvier’s is the
smallest, occupying all of the Gulf of
Alaska, south of the Canadian border
and west along the Aleutian Islands.
Baird’s range even farther south and
Baird’s and Stejneger’s also cross north
over the Aleutian Islands).
Regarding abundance and distribution
of these species in the vicinity of the
TMAA, passive acoustic data indicate
spatial overlap of all three beaked
whales; however, detections are
spatially offset, suggesting some level of
habitat portioning in the Gulf of Alaska
(Rice et al., 2021). Peaks in detections
by Rice et al. (2021) were also
temporally offset, with detections of
Baird’s beaked whale clicks peaking in
winter at the slope and in spring at the
seamounts. Rice et al. (2021) indicates
Baird’s beaked whales were highest in
number at Quinn seamount, which
overlaps with the southern edge of the
TMAA, and therefore, a portion of this
habitat is outside of the TMAA.
Baumann Pickering et al. (2012b) did
not acoustically detect Baird’s beaked
whales from July-October in the
northern Gulf of Alaska (overlapping
with the majority of the Navy’s potential
training period), while acoustic
detections from November-January
suggest that Baird’s beaked whales may
winter in this area. Rice et al. (2021)
reported the highest detections of
Baird’s beaked whales within the
TMAA during the spring in the portion
of the TMAA that is farther offshore,
with lowest detections in the summer
and an increase in detections on the
continental slope in the winter,
indicating that the whales are either not
producing clicks in the summer or they
E:\FR\FM\11AUP2.SGM
11AUP2
49752
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
are migrating farther north or south to
feed or mate during this time.
Data from a satellite-tagged Baird’s
beaked whale off Southern California
recently documented movement north
along the shelf-edge for more than 400
nmi over a six-and-a-half-day period
(Schorr et. al., Unpublished). If that
example is reflective of more general
behavior, Baird’s beaked whales present
in the TMAA may have much larger
home ranges than the waters bounded
by the TMAA, reducing the potential for
repeated takes of individuals.
Regarding Stejneger’s beaked whale,
passive acoustic monitoring detected
the whales most commonly at the slope
and offshore in the TMAA (Rice et al.,
2021; Rice et al., 2018b; Rice et al.,
2020b). At the slope, Stejneger’s beaked
whale detections peaked in fall (Rice et
al., 2021). Rice et al. (2021) notes that
to date, there have been no documented
sightings of Stejneger’s beaked whales
that were simultaneous with recording
of vocalizations, which is necessary to
confirm the vocalizations were
produced by the species, and therefore,
detections should be interpreted with
caution. Baumann-Pickering et al.
(2012b) recorded acoustic signals
believed to be produced by Stejneger’s
beaked whales (based on frequency
characteristics, interpulse interval, and
geographic location; Baumann-Pickering
et al., 2012a) almost weekly from July
2011 to February 2012 in the northern
Gulf of Alaska.
Regarding Cuvier’s beaked whale,
passive acoustic monitoring at five sites
in the TMAA (Rice et al., 2021; Rice et
al., 2015; Rice et al., 2018b; Rice et al.,
2020a) has intermittently detected
Cuvier’s beaked whale vocalizations in
low numbers in every month except
April, although there are generally
multiple months in any given year
where no detections are made.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), the anticipated takes
would occur within a small portion of
the stocks’ ranges (including that none
of the stocks are expected to occur in
the far western edge of the TMAA; U.S.
Department of the Navy, 2021) and
would occur within the 21-day window
of the annual activities. In consideration
of these factors and the passive acoustic
monitoring data described in this
section, which indicates relatively low
beaked whale presence in the TMAA
during the Navy’s potential training
period, it is likely that a portion of the
stocks would be taken, and a subset of
them may be taken on a few days, with
no indication that these days would be
sequential.
Regarding the severity of those
individual takes by Level B harassment
by behavioral disturbance, we have
explained that the duration of any
exposure is expected to be between
minutes and hours (i.e., relatively short)
and the received sound levels largely
below 166 dB, though with beaked
whales, which are considered somewhat
more sensitive, this could mean that
some individuals would leave preferred
habitat for a day (i.e., moderate level
takes). However, while interrupted
feeding bouts are a known response and
concern for odontocetes, we also know
that there are often viable alternative
habitat options nearby. Regarding the
severity of TTS takes (anticipated for
Cuvier’s and Stejneger’s beaked whales
only), they are expected to be low-level,
of short duration, and mostly not in a
frequency band that would be expected
to interfere with beaked whale
communication or other important lowfrequency cues. Therefore, the
associated lost opportunities and
capabilities are not at a level that would
impact reproduction or survival. As
mentioned earlier in the odontocete
overview, we anticipate more severe
effects from takes when animals are
exposed to higher received levels or
sequential days of impacts.
Altogether, none of these species are
ESA-listed, only a portion of the stocks
are anticipated to be impacted, and any
individual beaked whale is likely to be
disturbed at a moderate or sometimes
low level. This low magnitude and
moderate to lower severity of
harassment effects is not expected to
result in impacts on individual
reproduction or survival, let alone have
impacts on annual rates of recruitment
or survival of this stock. No mortality,
serious injury, or Level A harassment is
anticipated or proposed for
authorization. For these reasons, we
have preliminarily determined, in
consideration of all of the effects of the
Navy’s activities combined, that the
proposed authorized take would have a
negligible impact on the Alaska stocks
of beaked whales.
Dolphins and Small Whales
This section builds on the broader
odontocete discussion above and brings
together the discussion of the different
types and amounts of take that different
dolphin and small whale species and
stocks would likely incur, the
applicable mitigation, and the status of
the species and stocks to support the
preliminary negligible impact
determinations for each species or stock.
For all dolphin and small whale stocks
discussed here, no mortality or Level A
harassment is anticipated or proposed
for authorization.
In Table 44 below for dolphins and
small whales, we indicate the total
annual numbers of take by Level A
harassment and Level B harassment,
and a number indicating the instances
of total take as a percentage of
abundance.
TABLE 44—ANNUAL ESTIMATED TAKES BY LEVEL B HARASSMENT AND LEVEL A HARASSMENT FOR DOLPHINS AND SMALL
WHALES IN THE TMAA AND NUMBER INDICATING THE INSTANCES OF TOTAL TAKE AS A PERCENTAGE OF SPECIES/
STOCK ABUNDANCE
Instances of indicated types of incidental take 1
Level B harassment
Species
Stock
lotter on DSK11XQN23PROD with PROPOSALS2
Behavioral
disturbance
Killer whale ............................
Pacific white-sided dolphins ..
Eastern North Pacific Offshore.
Eastern North Pacific Gulf of
Alaska, Aleutian Islands,
and Bering Sea Transient.
North Pacific ..........................
Level A
harassment
TTS
(may also
include
disturbance)
Total takes
Abundance
(NMFS
SARs) 2
Instances of
total take as
percentage
of abundance
PTS
64
17
0
81
300
27.0
119
24
0
143
587
24.4
1,102
472
0
1,574
26,880
5.9
1 Estimated
impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate individuals, especially for disturbance.
2 Presented in the 2021 draft SARs or most recent SAR.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
PO 00000
Frm 00098
Fmt 4701
Sfmt 4702
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
As described above, the large majority
of Level B harassment by behavioral
disturbance to odontocetes, and thereby
dolphins and small whales, from hullmounted sonar (MFAS) in the TMAA
would result from received levels
between 160 and 172 dB SPL. Therefore,
the majority of takes by Level B
harassment are expected to be in the
form of low to occasionally moderate
responses of a generally shorter
duration. As mentioned earlier in this
section, we anticipate more severe
effects from takes when animals are
exposed to higher received levels or for
longer durations. Occasional milder
occurrences of Level B harassment by
behavioral disturbance are unlikely to
cause long-term consequences for
individual animals, much less have any
effect on annual rates of recruitment or
survival. No mortality, serious injury, or
Level A harassment is expected or
proposed for authorization.
Research and observations show that
if delphinids are exposed to sonar or
other active acoustic sources they may
react in a number of ways depending on
their experience with the sound source
and what activity they are engaged in at
the time of the acoustic exposure.
Delphinids may not react at all until the
sound source is approaching within a
few hundred meters to within a few
kilometers depending on the
environmental conditions and species.
Some dolphin species (the more surfacedwelling taxa—typically those with
‘‘dolphin’’ in the common name, such
as bottlenose dolphins, spotted
dolphins, spinner dolphins, roughtoothed dolphins, etc., but not Risso’s
dolphin), especially those residing in
more industrialized or busy areas, have
demonstrated more tolerance for
disturbance and loud sounds and many
of these species are known to approach
vessels to bow-ride. These species are
often considered generally less sensitive
to disturbance. Dolphins and small
whales that reside in deeper waters and
generally have fewer interactions with
human activities are more likely to
demonstrate more typical avoidance
reactions and foraging interruptions as
described above in the odontocete
overview.
Below we compile and summarize the
information that supports our
preliminary determinations that the
Navy’s activities would not adversely
affect any of the dolphins and small
whales through effects on annual rates
of recruitment or survival.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
Killer Whales (Eastern North Pacific
Offshore; Eastern North Pacific Gulf of
Alaska, Aleutian Islands, and Bering Sea
Transient)
No killer whale stocks in the TMAA
are listed as DPSs under the ESA, and
no BIAs for killer whales have been
identified in the GOA Study Area. The
Eastern North Pacific Offshore stock is
reported as ‘‘stable,’’ and the population
trend of the Eastern North Pacific Gulf
of Alaska, Aleutian Islands, and Bering
Sea Transient stock is unknown.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), the number of estimated
total instances of take compared to the
abundance is 27 percent for the Eastern
North Pacific Offshore stock and 24
percent for the Eastern North Pacific
Gulf of Alaska, Aleutian Islands, and
Bering Sea Transient stock. This
information indicates that only a
portion of each stock is likely impacted,
with those individuals disturbed on
likely one, but not more than a few nonsequential days within the 21 days per
year. Regarding the severity of those
individual takes by Level B harassment
by behavioral disturbance, we have
explained that the duration of any
exposure is expected to be between
minutes and hours (i.e., relatively short)
and the received sound levels largely
below 172 dB (i.e., of a lower, to
occasionally moderate, level and less
likely to evoke a severe response).
Regarding the severity of TTS takes,
they are expected to be low-level, of
short duration, and mostly not in a
frequency band that would be expected
to interfere with killer whale
communication or other important lowfrequency cues. Therefore, the
associated lost opportunities and
capabilities are not at a level that would
impact reproduction or survival.
Altogether, these killer whale stocks
are not listed under the ESA. The
Eastern North Pacific Offshore stock is
reported as ‘‘stable,’’ and the population
trend of the Eastern North Pacific Gulf
of Alaska, Aleutian Islands, and Bering
Sea Transient stock is unknown. Only a
portion of these killer whale stocks is
anticipated to be impacted, and any
individual is likely to be disturbed at a
low-moderate level, with the taken
individuals likely exposed on one day
but not more than a few non-sequential
days within a year. This low magnitude
and severity of harassment effects is
unlikely to result in impacts on
individual reproduction or survival, let
alone have impacts on annual rates of
recruitment or survival of either of the
stocks. No mortality or Level A
harassment is anticipated or proposed
PO 00000
Frm 00099
Fmt 4701
Sfmt 4702
49753
for authorization for either of the stocks.
For these reasons, we have preliminarily
determined, in consideration of all of
the effects of the Navy’s activities
combined, that the proposed authorized
take would have a negligible impact on
these killer whale stocks.
Pacific White-Sided Dolphins (North
Pacific Stock)
Pacific white-sided dolphins are not
listed under the ESA and the current
population trend of the North Pacific
stock is unknown. No BIAs for this
stock have been identified in the GOA
Study Area.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), the number of estimated
total instances of take compared to the
abundance is 6 percent. Given the
number of takes, only a small portion of
the stock is likely impacted, and
individuals are likely disturbed between
one and a few days, most likely nonsequential, within a year. Regarding the
severity of those individual takes by
Level B harassment by behavioral
disturbance, we have explained that the
duration of any exposure is expected to
be between minutes and hours (i.e.,
relatively short) and the received sound
levels largely below 172 dB (i.e., of a
lower, to occasionally moderate, level
and less likely to evoke a severe
response). However, while interrupted
feeding bouts are a known response and
concern for odontocetes, we also know
that there are often viable alternative
habitat options nearby. Regarding the
severity of TTS takes, they are expected
to be low-level, of short duration, and
mostly not in a frequency band that
would be expected to interfere with
dolphin communication or other
important low-frequency cues.
Therefore, the associated lost
opportunities and capabilities are not at
a level that would impact reproduction
or survival.
Altogether, though the status of this
stock is unknown, this stock is not
listed under the ESA. Any individual is
likely to be disturbed at a low-moderate
level, and those individuals likely
disturbed on one to a few nonsequential days within a year. This low
magnitude and severity of harassment
effects is not expected to result in
impacts on individual reproduction or
survival, let alone have impacts on
annual rates of recruitment or survival
of this stock. No mortality, serious
injury, or Level A harassment is
anticipated or proposed for
authorization. For these reasons, we
have preliminarily determined, in
consideration of all of the effects of the
Navy’s activities combined, that the
E:\FR\FM\11AUP2.SGM
11AUP2
49754
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
proposed authorized take would have a
negligible impact on the North Pacific
stock of Pacific white-sided dolphins.
Dall’s Porpoise (Alaska Stock)
This section builds on the broader
odontocete discussion above and brings
together the discussion of the different
types and amounts of take that this
porpoise stock would likely incur, the
applicable mitigation, and the status of
the stock to support the negligible
impact determination.
In Table 45 below for Dall’s porpoise,
we indicate the total annual numbers of
take by Level A harassment and Level
B harassment, and a number indicating
the instances of total take as a
percentage of abundance.
TABLE 45—ANNUAL ESTIMATED TAKES BY LEVEL B HARASSMENT AND LEVEL A HARASSMENT FOR DALL’S PORPOISE IN
THE TMAA AND NUMBER INDICATING THE INSTANCES OF TOTAL TAKE AS A PERCENTAGE OF SPECIES/STOCK ABUNDANCE
Instances of indicated types of incidental take 1
Level B harassment
Species
Stock
Behavioral
disturbance
Dall’s porpoise .......................
Alaska ....................................
348
TTS
(may also
include
disturbance)
8,939
Level A
harassment
Total takes
Abundance
(NMFS
SARs) 2
Instances of
total take as
percentage
of abundance
9,351
83,400
11.2
PTS
64
1 Estimated
lotter on DSK11XQN23PROD with PROPOSALS2
impacts are based on the maximum number of activities in a given year under the Specified Activity. Not all takes represent separate individuals, especially for disturbance.
2 Presented in the 2021 draft SARs or most recent SAR.
Dall’s porpoise is not listed under the
ESA and the current population trend
for the Alaska stock is unknown. No
BIAs for Dall’s porpoise have been
identified in the GOA Study Area.
While harbor porpoises have been
observed to be especially sensitive to
human activity, the same types of
responses have not been observed in
Dall’s porpoises. Dall’s porpoises are
typically notably longer than, and weigh
more than twice as much as, harbor
porpoises, making them generally less
likely to be preyed upon and likely
differentiating their behavioral
repertoire somewhat from harbor
porpoises. Further, they are typically
seen in large groups and feeding
aggregations, or exhibiting bow-riding
behaviors, which is very different from
the group dynamics observed in the
more typically solitary, cryptic harbor
porpoises, which are not often seen
bow-riding. For these reasons, Dall’s
porpoises are not treated as an
especially sensitive species (versus
harbor porpoises which have a lower
behavioral harassment threshold and
more distant cutoff) but, rather, are
analyzed similarly to other odontocetes
(with takes from the sonar bin in the
TMAA resulting from the same received
levels reported in the Odontocete
section above). Therefore, the majority
of Level B harassment by behavioral
disturbance is expected to be in the
form of milder responses compared to
higher level exposures. As mentioned
earlier in this section, we anticipate
more severe effects from takes when
animals are exposed to higher received
levels.
We note that Dall’s porpoise, as a HFsensitive species, has a lower PTS
threshold than other groups and
therefore is generally more likely to
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
experience TTS and PTS, and
potentially occasionally to a greater
degree, and NMFS accordingly has
evaluated and authorized higher
numbers. Also, however, regarding PTS
from sonar exposure, porpoises are still
likely to avoid sound levels that would
cause higher levels of TTS (greater than
20 dB) or PTS. Therefore, even though
the number of TTS takes are higher than
for other odontocetes, any PTS is
expected to be at a lower to occasionally
moderate level and for all of the reasons
described above, TTS and PTS takes are
not expected to impact reproduction or
survival of any individual.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance), the number of estimated
total instances of take compared to the
abundance is 11 percent. This indicates
that only a small portion of this stock
is likely to be impacted, and a subset of
those individuals would likely be taken
on no more than a few non-sequential
days within a year. Regarding the
severity of those individual takes by
Level B harassment by behavioral
disturbance, we have explained that the
duration of any exposure is expected to
be between minutes and hours (i.e.,
relatively short) and the received sound
levels largely below 172 dB (i.e., of a
lower, to occasionally moderate, level
and less likely to evoke a severe
response). Regarding the severity of TTS
takes, they are expected to be low-level,
of short duration, and mostly not in a
frequency band that would be expected
to interfere with communication or
other important low-frequency cues.
Therefore, the associated lost
opportunities and capabilities are not at
a level that would impact reproduction
or survival.
PO 00000
Frm 00100
Fmt 4701
Sfmt 4702
For the same reasons explained above
for TTS (low to occasionally moderate
level and the likely frequency band),
while a small permanent loss of hearing
sensitivity may include some degree of
energetic costs for compensating or may
mean some small loss of opportunities
or detection capabilities, the estimated
annual takes by Level A harassment by
PTS for this stock (64 takes) would be
unlikely to impact behaviors,
opportunities, or detection capabilities
to a degree that would interfere with
reproductive success or survival of any
individuals.
Altogether, the status of the Alaska
stock of Dall’s porpoise is unknown,
however Dall’s porpoise are not listed as
endangered or threatened under the
ESA. Only a small portion of this stock
is likely to be impacted, any individual
is likely to be disturbed at a lowmoderate level, and a subset of taken
individuals would likely be taken on a
few non-sequential days within a year.
This low magnitude and severity of
Level B harassment effects is not
expected to result in impacts on
individual reproduction or survival,
much less annual rates of recruitment or
survival. Some individuals (64
annually) could be taken by PTS of
likely low to occasionally moderate
severity. A small permanent loss of
hearing sensitivity (PTS) may include
some degree of energetic costs for
compensating or may mean some small
loss of opportunities or detection
capabilities, but at the expected scale
the estimated takes by Level A
harassment by PTS for this stock would
be unlikely, alone or in combination
with the Level B harassment take by
behavioral disturbance and TTS, to
impact behaviors, opportunities, or
detection capabilities to a degree that
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
would interfere with reproductive
success or survival of any individuals,
let alone have impacts on annual rates
of recruitment or survival of this stock.
No mortality or serious injury and no
Level A harassment from non-auditory
tissue damage is anticipated or
proposed for authorization. For these
reasons, we have preliminarily
determined, in consideration of all of
the effects of the Navy’s activities
combined, that the proposed authorized
take would have a negligible impact on
the Alaska stock of Dall’s porpoise.
Pinnipeds
This section builds on the broader
discussion above and brings together the
discussion of the different types and
amounts of take that different species
and stocks would likely incur, the
applicable mitigation, and the status of
the species and stocks to support the
negligible impact determinations for
each species or stock. We have
described (earlier in this section) the
unlikelihood of any masking having
effects that would impact the
reproduction or survival of any of the
individual marine mammals affected by
the Navy’s activities. We have also
described above in the Potential Effects
of Specified Activities on Marine
Mammals and their Habitat section the
unlikelihood of any habitat impacts
having effects that would impact the
reproduction or survival of any of the
individual marine mammals affected by
the Navy’s activities. For pinnipeds,
there is no mortality or serious injury
and no Level A harassment from nonauditory tissue damage from sonar or
explosives anticipated or proposed to be
authorized for any species.
Regarding behavioral disturbance,
research and observations show that
pinnipeds in the water may be tolerant
of anthropogenic noise and activity (a
review of behavioral reactions by
pinnipeds to impulsive and nonimpulsive noise can be found in
Richardson et al. (1995) and Southall et
al. (2007)). Available data, though
limited, suggest that exposures between
approximately 90 and 140 dB SPL do
not appear to induce strong behavioral
responses in pinnipeds exposed to nonpulse sounds in water (Costa et al.,
2003; Jacobs and Terhune, 2002;
Kastelein et al., 2006c). Based on the
limited data on pinnipeds in the water
exposed to multiple pulses (small
explosives, impact pile driving, and
seismic sources), exposures in the
approximately 150 to 180 dB SPL range
generally have limited potential to
induce avoidance behavior in pinnipeds
(Blackwell et al., 2004; Harris et al.,
2001; Miller et al., 2004). If pinnipeds
are exposed to sonar or other active
acoustic sources they may react in a
number of ways depending on their
experience with the sound source and
what activity they are engaged in at the
time of the acoustic exposure. Pinnipeds
may not react at all until the sound
source is approaching within a few
hundred meters and then may alert,
ignore the stimulus, change their
behaviors, or avoid the immediate area
by swimming away or diving. Effects on
pinnipeds that are taken by Level B
harassment in the TMAA, on the basis
of reports in the literature as well as
Navy monitoring from past activities,
would likely be limited to reactions
such as increased swimming speeds,
increased surfacing time, or decreased
foraging (if such activity were
49755
occurring). Most likely, individuals
would simply move away from the
sound source and be temporarily
displaced from those areas, or not
respond at all, which would have no
effect on reproduction or survival.
While some animals may not return to
an area, or may begin using an area
differently due to training activities,
most animals are expected to return to
their usual locations and behavior.
Given their documented tolerance of
anthropogenic sound (Richardson et al.,
1995 and Southall et al., 2007), repeated
exposures of individuals of any of these
species to levels of sound that may
cause Level B harassment are unlikely
to result in hearing impairment or to
significantly disrupt foraging behavior.
Thus, even repeated Level B harassment
of some small subset of individuals of
an overall stock is unlikely to result in
any significant realized decrease in
fitness to those individuals that would
result in any adverse impact on rates of
recruitment or survival for the stock as
a whole.
While no take of Steller sea lion is
anticipated or proposed to be
authorized, we note that the GOA Study
Area boundary was intentionally
designed to avoid ESA-designated
Steller sea lion critical habitat.
All the pinniped species discussed in
this section would benefit from the
procedural mitigation measures
described earlier in the Proposed
Mitigation Measures section.
In Table 46 below for pinnipeds, we
indicate the total annual numbers of
take by Level A harassment and Level
B harassment, and a number indicating
the instances of total take as a
percentage of abundance.
TABLE 46—ANNUAL ESTIMATED TAKES BY LEVEL B HARASSMENT AND LEVEL A HARASSMENT FOR PINNIPEDS IN THE
TMAA AND NUMBER INDICATING THE INSTANCES OF TOTAL TAKE AS A PERCENTAGE OF SPECIES/STOCK ABUNDANCE
Instances of indicated types of incidental take 1
Level B harassment
Species
Stock
Behavioral
disturbance
Northern fur seal ...................
Northern fur seal ...................
Northern elephant seal ..........
Eastern Pacific ......................
California ...............................
California ...............................
2,972
60
904
Level A
harassment
TTS
(may also
include
disturbance)
Total Takes
Abundance
(NMFS
SARs) 2
Instances of
total take as
percentage
of abundance
PTS
31
1
1,643
0
0
8
3,003
61
2,555
626,618
14,050
187,386
<1
<1
1.3
lotter on DSK11XQN23PROD with PROPOSALS2
1 Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate individuals, especially for disturbance.
2 Presented in the 2021 draft SARs or most recent SAR.
The majority of takes by harassment
of pinnipeds in the TMAA are caused
by sources from the MFAS bin (which
includes hull-mounted sonar) because
they are high level sources at a
frequency (1–10 kHz) which overlaps
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
the most sensitive portion of the
pinniped hearing range, and of the
sources expected to result in take, they
are used in a large portion of exercises
(see Table 1 and Table 3). Most of the
takes (>99 percent) from the MF1 bin in
PO 00000
Frm 00101
Fmt 4701
Sfmt 4702
the TMAA would result from received
levels between 166 and 178 dB SPL. For
the remaining active sonar bin types, the
percentages are as follows: MF4 = 97
percent between 148 and 172 dB SPL
and MF5 = 99 percent between 130 and
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49756
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
160 dB SPL. Given the levels they are
exposed to and pinniped sensitivity,
most responses would be of a lower
severity, with only occasional responses
likely to be considered moderate, but
still of generally short duration.
As mentioned earlier in this section,
we anticipate more severe effects from
takes when animals are exposed to
higher received levels. Occasional
milder takes by Level B harassment by
behavioral disturbance are unlikely to
cause long-term consequences for
individual animals or populations,
especially when they are not expected
to be repeated over sequential multiple
days. For all pinnipeds except Northern
elephant seals, no take is expected to
occur from explosives. For Northern
elephant seals, harassment takes from
explosives (behavioral disturbance,
TTS, and PTS) comprise a very small
fraction of those caused by exposure to
active sonar.
Because the majority of harassment
takes of pinnipeds result from
narrowband sources in the range of 1–
10 kHz, the vast majority of threshold
shift caused by Navy sonar sources
would typically occur in the range of 2–
20 kHz. This frequency range falls
within the range of pinniped hearing,
however, pinniped vocalizations
typically span a somewhat lower range
than this (<0.2 to 10 kHz) and threshold
shift from active sonar would often be
in a narrower band (reflecting the
narrower band source that caused it),
which means that TTS incurred by
pinnipeds would typically only
interfere with communication within a
portion of a pinniped’s range (if it
occurred during a time when
communication with conspecifics was
occurring). As discussed earlier, it
would only be expected to be of a short
duration and relatively small degree.
Many of the other critical sounds that
serve as cues for navigation and prey
(e.g., waves, fish, invertebrates) occur
below a few kHz, which means that
detection of these signals would not be
inhibited by most threshold shifts
either. The very low number of takes by
threshold shifts that might be incurred
by individuals exposed to explosives
would likely be lower frequency (5 kHz
or less) and spanning a wider frequency
range, which could slightly lower an
individual’s sensitivity to navigational
or prey cues, or a small portion of
communication calls, for several
minutes to hours (if temporary) or
permanently.
Neither of these species are ESAlisted and the SAR indicates that the
status of the Eastern Pacific stock of
Northern fur seal is stable, the California
stock of Northern fur seal is increasing,
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
and the California stock of Northern
elephant seal is increasing. BIAs have
not been identified for pinnipeds.
Regarding the magnitude of takes by
Level B harassment (TTS and behavioral
disturbance) for the Eastern Pacific and
California stocks of Northern fur seals,
the estimated instances of takes as
compared to the stock abundance is <1
percent for each stock. For the
California stock of Northern elephant
seal, the number of estimated total
instances of take compared to the
abundance is 1 percent. This
information indicates that only a very
small portion of individuals in these
stocks are likely impacted, particularly
given the large ranges of the stocks.
Impacted individuals would be
disturbed on likely one, but not more
than a few non-sequential days within
a year.
Regarding the severity of those
individual takes by Level B harassment
by behavioral disturbance for all
pinniped stocks, we have explained that
the duration of any exposure is expected
to be between minutes and hours (i.e.,
relatively short) and the received sound
levels largely below 178 dB, which is
considered a relatively low to
occasionally moderate level for
pinnipeds.
Regarding the severity of TTS takes,
they are expected to be low-level, of
short duration, and mostly not in a
frequency band that would be expected
to interfere with pinniped
communication or other important lowfrequency cues. Therefore, the
associated lost opportunities and
capabilities are not at a level that would
impact reproduction or survival. For
these same reasons (low level and
frequency band), while a small
permanent loss of hearing sensitivity
may include some degree of energetic
costs for compensating or may mean
some small loss of opportunities or
detection capabilities, the 8 estimated
Level A harassment takes by PTS for the
California stock of Northern elephant
seal would be unlikely to impact
behaviors, opportunities, or detection
capabilities to a degree that would
interfere with reproductive success or
survival of any individuals.
Altogether, none of these species are
listed under the ESA, and the SARs
indicate that the status of the Eastern
Pacific stock of Northern fur seal is
stable, the California stock of Northern
fur seal is increasing, and the California
stock of Northern elephant seal is
increasing. No mortality or serious
injury and no Level A harassment from
non-auditory tissue damage for
pinnipeds is anticipated or proposed for
authorization. Level A harassment by
PO 00000
Frm 00102
Fmt 4701
Sfmt 4702
PTS is only anticipated for the
California stock of Northern elephant
seal (8 takes by Level A harassment).
For all three pinniped stocks, only a
small portion of the stocks are
anticipated to be impacted and any
individual is likely to be disturbed at a
low-moderate level. This low magnitude
and severity of harassment effects is not
expected to result in impacts on
individual reproduction or survival, let
alone have impacts on annual rates of
recruitment or survival of these stocks.
For these reasons, in consideration of all
of the effects of the Navy’s activities
combined, we have preliminarily
determined that the proposed
authorized take would have a negligible
impact on all three stocks of pinnipeds.
Preliminary Determination
Based on the analysis contained
herein of the likely effects of the
specified activity on marine mammals
and their habitat, and taking into
consideration the implementation of the
proposed monitoring and mitigation
measures, NMFS preliminarily finds
that the total marine mammal take from
the specified activities will have a
negligible impact on all affected marine
mammal species or stocks.
Subsistence Harvest of Marine
Mammals
In order to issue an incidental take
authorization, NMFS must find that the
specified activity will not have an
‘‘unmitigable adverse impact’’ on the
subsistence uses of the affected marine
mammal species or stocks by Alaska
Natives. NMFS has defined
‘‘unmitigable adverse impact’’ in 50 CFR
216.103 as an impact resulting from the
specified activity: (1) That is likely to
reduce the availability of the species to
a level insufficient for a harvest to meet
subsistence needs by: (i) Causing the
marine mammals to abandon or avoid
hunting areas; (ii) Directly displacing
subsistence users; or (iii) Placing
physical barriers between the marine
mammals and the subsistence hunters;
and (2) That cannot be sufficiently
mitigated by other measures to increase
the availability of marine mammals to
allow subsistence needs to be met.
When applicable, NMFS must
prescribe means of effecting the least
practicable adverse impact on the
availability of the species or stocks for
subsistence uses. As discussed in the
Proposed Mitigation Measures section,
evaluation of potential mitigation
measures includes consideration of two
primary factors: (1) The manner in
which, and the degree to which,
implementation of the potential
measure(s) is expected to reduce
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
adverse impacts on the availability of
species or stocks for subsistence uses,
and (2) the practicability of the
measure(s) for applicant
implementation.
The Navy has met with and will
continue to engage in meaningful
consultation and communication with
several federally recognized Alaska
Native tribes that have traditional
marine mammal harvest areas in the
GOA (though, as noted below, these
areas do not overlap directly with the
GOA Study Area). Further, the Navy
will continue to keep the Tribes
informed of the timeframes of future
joint training exercises.
To our knowledge, subsistence
hunting of marine mammals does not
occur in the GOA Study Area where
training activities would occur. The
GOA Study Area is located over 12 nmi
from shore with the nearest inhabited
land being the Kenai Peninsula (24 nmi
from the GOA Study Area). Information
provided by Tribes in previous
conversations with the Navy, and
according to Alaska Department of Fish
and Game (1995), indicates that harvest
of pinnipeds occurs nearshore, and the
Tribes do not use the GOA Study Area
for subsistence hunting of marine
mammals. The TMAA portion of the
GOA Study Area is the closest to the
area of nearshore subsistence harvest
conducted by the Sun’aq Tribe of
Kodiak, the Native Village of Eyak, and
the Yakutat Tlingit Tribe (Alaska
Department of Fish and Game, 1995).
The WMA is offshore of subsistence
harvest areas that occur in Unalaska,
Akutan, False Pass, Sand Point, and
King Cove (Alaska Department of Fish
and Game, 1997). The Tribes listed here
harvest harbor seals and sea lions
(Alaska Department of Fish and Game,
1995, 1997).
In addition to the distance between
subsistence hunting areas and the GOA
Study Area, which would ensure that
the Navy’s activities do not displace
subsistence users or place physical
barriers between the marine mammals
and the subsistence hunters, there is no
reason to believe that any behavioral
disturbance or limited TTS or PTS of
pinnipeds that occurs offshore in the
GOA Study Area would affect their
subsequent behavior in a manner that
would interfere with subsistence uses
should those pinnipeds later interact
with hunters, particularly given that
neither harbor seals, Steller sea lions, or
California sea lions are expected to be
taken by the Navy’s training activities.
The specified activity would be a
continuation of the types of training
activities that have been ongoing for
more than a decade, and as discussed in
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
the 2011 GOA FEIS/OEIS and 2016
GOA FSEIS/OEIS, no impacts on
traditional subsistence practices or
resources are predicted to result from
the specified activity.
Based on the information above,
NMFS has preliminarily determined
that the total taking of affected species
or stocks would not have an unmitigable
adverse impact on the availability of the
species or stocks for taking for
subsistence purposes. However, we
have limited information on marine
mammal subsistence use in the GOA
Study Area and seek additional
information pertinent to making the
final determination.
Classification
Endangered Species Act
There are eight marine mammal
species under NMFS jurisdiction that
are listed as endangered or threatened
under the ESA with confirmed or
possible occurrence in the GOA Study
Area: North Pacific right whale,
humpback whale (Mexico, Western
North Pacific, and Central America
DPSs), blue whale, fin whale, sei whale,
gray whale (Western North Pacific
stock), sperm whale, and Steller sea lion
(Western DPS). The humpback whale
has critical habitat recently designated
under the ESA in the TMAA portion of
the GOA Study Area (86 FR 21082;
April 21, 2021). As discussed
previously, the GOA Study Area
boundaries were intentionally designed
to avoid ESA-designated critical habitat
for Steller sea lions.
The Navy will consult with NMFS
pursuant to section 7 of the ESA for
GOA Study Area activities. NMFS will
also consult internally on the issuance
of the regulations and an LOA under
section 101(a)(5)(A) of the MMPA.
National Environmental Policy Act
To comply with the National
Environmental Policy Act of 1969
(NEPA; 42 U.S.C. 4321 et seq.) and
NOAA Administrative Order (NAO)
216–6A, NMFS must evaluate our
proposed actions and alternatives with
respect to potential impacts on the
human environment. Accordingly,
NMFS plans to adopt the GOA SEIS/
OEIS for the GOA Study Area provided
our independent evaluation of the
document finds that it includes
adequate information analyzing the
effects on the human environment of
issuing regulations and an LOA under
the MMPA. NMFS is a cooperating
agency on the 2020 GOA DSEIS/OEIS
and 2022 Supplement to the 2020 GOA
DSEIS/OEIS and has worked extensively
with the Navy in developing the
PO 00000
Frm 00103
Fmt 4701
Sfmt 4702
49757
documents. The 2020 GOA DSEIS/OEIS
and 2022 Supplement to the 2020 GOA
DSEIS/OEIS were made available for
public comment in February 2020 and
March 2022, respectively, at https://
www.goaeis.com/, which also provides
additional information about the NEPA
process. We will review all comments
prior to concluding our NEPA process
and making a final decision on the
MMPA rulemaking and request for a
LOA.
Regulatory Flexibility Act
The Office of Management and Budget
has determined that this proposed rule
is not significant for purposes of
Executive Order 12866.
Pursuant to the Regulatory Flexibility
Act (RFA), the Chief Counsel for
Regulation of the Department of
Commerce has certified to the Chief
Counsel for Advocacy of the Small
Business Administration that this
proposed rule, if adopted, would not
have a significant economic impact on
a substantial number of small entities.
The RFA requires Federal agencies to
prepare an analysis of a rule’s impact on
small entities whenever the agency is
required to publish a notice of proposed
rulemaking. However, a Federal agency
may certify, pursuant to 5 U.S.C. 605(b),
that the action will not have a
significant economic impact on a
substantial number of small entities.
The Navy is the sole entity that would
be affected by this rulemaking, and the
Navy is not a small governmental
jurisdiction, small organization, or small
business, as defined by the RFA. Any
requirements imposed by an LOA
issued pursuant to these regulations,
and any monitoring or reporting
requirements imposed by these
regulations, would be applicable only to
the Navy. NMFS does not expect the
issuance of these regulations or the
associated LOA to result in any impacts
to small entities pursuant to the RFA.
Because this action, if adopted, would
directly affect the Navy and not a small
entity, NMFS concludes that the action
would not result in a significant
economic impact on a substantial
number of small entities.
List of Subjects in 50 CFR Part 218
Exports, Fish, Imports, Incidental
take, Indians, Labeling, Marine
mammals, Navy, Penalties, Reporting
and recordkeeping requirements,
Seafood, Sonar, Transportation.
E:\FR\FM\11AUP2.SGM
11AUP2
49758
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
Dated: July 28, 2022.
Samuel D. Rauch, III,
Deputy Assistant Administrator for
Regulatory Programs, National Marine
Fisheries Service.
218.157 Renewals and modifications of
Letter of Authorization.
218.158 [Reserved]
For reasons set forth in the preamble,
50 CFR part 218 is proposed to be
amended as follows:
(a) Regulations in this subpart apply
only to the U.S. Navy (Navy) for the
taking of marine mammals that occurs
in the area described in paragraph (b) of
this section and that occurs incidental
to the activities listed in paragraph (c)
of this section.
(b) The GOA Study Area is entirely at
sea and is comprised of three areas: a
Temporary Maritime Activities Area
(TMAA) a warning area, and the
Western Maneuver Area (WMA) located
south and west of the TMAA. The
TMAA and WMA are temporary areas
established within the GOA for ships,
submarines, and aircraft to conduct
training activities. The TMAA is a
polygon roughly resembling a rectangle
oriented from northwest to southeast,
approximately 300 nautical miles (nmi;
556 km) in length by 150 nmi (278 km)
in width, located south of Montague
Island and east of Kodiak Island. The
warning area overlaps and extends
slightly beyond the northern corner of
the TMAA. The WMA provides an
additional 185,806 nmi2 of surface, subsurface, and airspace training area to
support activities occurring within the
§ 218.150 Specified activity and
geographical region.
PART 218—REGULATIONS
GOVERNING THE TAKING AND
IMPORTING OF MARINE MAMMALS
1. The authority citation for part 218
continues to read as follows:
■
Authority: 16 U.S.C. 1361 et seq., unless
otherwise noted.
■
2. Revise subpart P to read as follows:
Subpart P—Taking and Importing
Marine Mammals; U.S. Navy Training
Activities in the Gulf of Alaska Study
Area
Sec.
218.150 Specified activity and geographical
region.
218.151 Effective dates.
218.152 Permissible methods of taking.
218.153 Prohibitions.
218.154 Mitigation requirements.
218.155 Requirements for monitoring and
reporting.
218.156 Letters of Authorization.
TMAA. The boundary of the WMA
follows the bottom of the slope at the
4,000 m contour line.
(c) The taking of marine mammals by
the Navy is only authorized if it occurs
incidental to the Navy conducting
training activities, including:
(1) Anti-submarine warfare; and
(2) Surface warfare.
§ 218.151
Effective dates.
Regulations in this subpart are
effective from December 15, 2022
through December 14, 2029.
§ 218.152
Permissible methods of taking.
(a) Under a Letter of Authorization
(LOA) issued pursuant to § 216.106 of
this chapter and § 218.156, the Holder of
the LOA (hereinafter ‘‘Navy’’) may
incidentally, but not intentionally, take
marine mammals within the TMAA
only, as described in § 218.150(b), by
Level A harassment and Level B
harassment associated with the use of
active sonar and other acoustic sources
and explosives, provided the activity is
in compliance with all terms,
conditions, and requirements of this
subpart and the applicable LOA.
(b) The incidental take of marine
mammals by the activities listed in
§ 218.150(c) is limited to the following
species:
TABLE 1 TO § 218.152(b)
Species
Stock
lotter on DSK11XQN23PROD with PROPOSALS2
Blue whale ..........................................................
Blue whale ..........................................................
Fin whale ............................................................
Humpback whale ................................................
Humpback whale ................................................
Humpback whale ................................................
Minke whale ........................................................
North Pacific right whale .....................................
Sei whale ............................................................
Gray whale ..........................................................
Killer whale .........................................................
Killer whale .........................................................
Pacific white-sided dolphin .................................
Dall’s porpoise ....................................................
Sperm whale .......................................................
Baird’s beaked whale .........................................
Cuvier’s beaked whale .......................................
Stejneger’s beaked whale ..................................
Northern fur seal .................................................
Northern fur seal .................................................
Northern elephant seal .......................................
§ 218.153
Prohibitions.
(a) Except for incidental takings
contemplated in § 218.152(a) and
authorized by an LOA issued under
§§ 216.106 of this chapter and 218.156,
it shall be unlawful for any person to do
any of the following in connection with
the activities listed in § 218.150(c):
VerDate Sep<11>2014
18:47 Aug 10, 2022
Jkt 256001
Central North Pacific.
Eastern North Pacific.
Northeast Pacific.
Western North Pacific.
Central North Pacific.
California/Oregon/Washington.
Alaska.
Eastern North Pacific.
Eastern North Pacific.
Eastern North Pacific.
Eastern North Pacific Offshore.
Eastern North Pacific Gulf of Alaska, Aleutian Islands, and Bering Sea Transient.
North Pacific.
Alaska.
North Pacific.
Alaska.
Alaska.
Alaska.
Eastern Pacific.
California.
California.
(1) Violate, or fail to comply with, the
terms, conditions, and requirements of
this subpart or an LOA issued under
§§ 216.106 of this chapter and 218.156;
(2) Take any marine mammal not
specified in § 218.152(b);
PO 00000
Frm 00104
Fmt 4701
Sfmt 4702
(3) Take any marine mammal
specified in § 218.152(b) in any manner
other than as specified in the LOA; or
(4) Take a marine mammal specified
in § 218.152(b) if NMFS determines
such taking results in more than a
negligible impact on the species or
stocks of such marine mammal.
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
(b) [Reserved]
lotter on DSK11XQN23PROD with PROPOSALS2
§ 218.154
Mitigation requirements.
(a) When conducting the activities
identified in § 218.150(c), the mitigation
measures contained in any LOA issued
under §§ 216.106 of this chapter and
218.156 must be implemented. These
mitigation measures include, but are not
limited to:
(1) Procedural mitigation. Procedural
mitigation is mitigation that the Navy
must implement whenever and
wherever an applicable training activity
takes place within the GOA Study Area
for acoustic stressors (i.e., active sonar,
weapons firing noise), explosive
stressors (i.e., large-caliber projectiles,
bombs), and physical disturbance and
strike stressors (i.e., vessel movement,
towed in-water devices, small-,
medium-, and large-caliber nonexplosive practice munitions, nonexplosive bombs).
(i) Environmental awareness and
education. Appropriate Navy personnel
(including civilian personnel) involved
in mitigation and training activity
reporting under the specified activities
will complete the environmental
compliance training modules identified
in their career path training plan, as
specified in the LOA.
(ii) Active sonar. Active sonar
includes mid-frequency active sonar,
and high-frequency active sonar. For
vessel-based active sonar activities,
mitigation applies only to sources that
are positively controlled and deployed
from manned surface vessels (e.g., sonar
sources towed from manned surface
platforms). For aircraft-based active
sonar activities, mitigation applies only
to sources that are positively controlled
and deployed from manned aircraft that
do not operate at high altitudes (e.g.,
rotary-wing aircraft). Mitigation does
not apply to active sonar sources
deployed from unmanned aircraft or
aircraft operating at high altitudes (e.g.,
maritime patrol aircraft).
(A) Number of Lookouts and
observation platform for hull-mounted
sources. For hull-mounted sources, the
Navy must have one Lookout for
platforms with space or manning
restrictions while underway (at the
forward part of a small boat or ship) and
platforms using active sonar while
moored or at anchor; and two Lookouts
for platforms without space or manning
restrictions while underway (at the
forward part of the ship).
(B) Number of Lookouts and
observation platform for sources not
hull-mounted. For sources that are not
hull-mounted, the Navy must have one
Lookout on the ship or aircraft
conducting the activity.
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
(C) Prior to activity. Prior to the initial
start of the activity (e.g., when
maneuvering on station), Navy
personnel must observe the mitigation
zone for floating vegetation and marine
mammals; if floating vegetation or a
marine mammal is observed, Navy
personnel must relocate or delay the
start of active sonar transmission until
the mitigation zone is clear of floating
vegetation or until the conditions in
paragraph (a)(1)(ii)(F) of this section are
met for marine mammals.
(D) During the activity for hullmounted mid-frequency active sonar.
During the activity, for hull-mounted
mid-frequency active sonar, Navy
personnel must observe the following
mitigation zones for marine mammals.
(1) Powerdowns for marine mammals.
Navy personnel must power down
active sonar transmission by 6 dB if a
marine mammal is observed within
1,000 yd (914.4 m) of the sonar source;
Navy personnel must power down
active sonar transmission an additional
4 dB (10 dB total) if a marine mammal
is observed within 500 yd (457.2 m) of
the sonar source.
(2) Shutdowns for marine mammals.
Navy personnel must cease transmission
if a marine mammal is observed within
200 yd (182.9 m) of the sonar source.
(E) During the activity, for midfrequency active sonar sources that are
not hull-mounted, and high-frequency
active sonar. During the activity, for
mid-frequency active sonar sources that
are not hull-mounted and highfrequency active sonar, Navy personnel
must observe the mitigation zone for
marine mammals. Navy personnel must
cease transmission if a marine mammal
is observed within 200 yd (182.9 m) of
the sonar source.
(F) Commencement/recommencement
conditions after a marine mammal
sighting before or during the activity.
Navy personnel must allow a sighted
marine mammal to leave the mitigation
zone prior to the initial start of the
activity (by delaying the start) or during
the activity (by not recommencing or
powering up active sonar transmission)
until one of the following conditions
has been met:
(1) Observed exiting. The animal is
observed exiting the mitigation zone;
(2) Thought to have exited. The
animal is thought to have exited the
mitigation zone based on a
determination of its course, speed, and
movement relative to the sonar source;
(3) Clear from additional sightings.
The mitigation zone has been clear from
any additional sightings for 10 minutes
(min) for aircraft-deployed sonar
sources or 30 minutes for vesseldeployed sonar sources;
PO 00000
Frm 00105
Fmt 4701
Sfmt 4702
49759
(4) Sonar source transit. For mobile
activities, the active sonar source has
transited a distance equal to double that
of the mitigation zone size beyond the
location of the last sighting; or
(5) Bow-riding dolphins. For activities
using hull-mounted sonar, the Lookout
concludes that dolphins are deliberately
closing in on the ship to ride the ship’s
bow wave, and are therefore out of the
main transmission axis of the sonar (and
there are no other marine mammal
sightings within the mitigation zone).
(iii) Weapons firing noise. Weapons
firing noise associated with large-caliber
gunnery activities.
(A) Number of Lookouts and
observation platform. One Lookout must
be positioned on the ship conducting
the firing. Depending on the activity, the
Lookout could be the same as the one
provided for under ‘‘Explosive largecaliber projectiles’’ or under ‘‘Small-,
medium-, and large-caliber nonexplosive practice munitions’’ in
paragraphs (a)(1)(iv)(A) and
(a)(1)(viii)(A) of this section.
(B) Mitigation zone. Thirty degrees on
either side of the firing line out to 70 yd
(64 m) from the muzzle of the weapon
being fired.
(C) Prior to activity. Prior to the initial
start of the activity, Navy personnel
must observe the mitigation zone for
floating vegetation and marine
mammals; if floating vegetation or a
marine mammal is observed, Navy
personnel must relocate or delay the
start of weapons firing until the
mitigation zone is clear of floating
vegetation or until the conditions in
paragraph (a)(1)(iii)(E) of this section are
met for marine mammals.
(D) During activity. During the
activity, Navy personnel must observe
the mitigation zone for marine
mammals; if a marine mammal is
observed, Navy personnel must cease
weapons firing.
(E) Commencement/recommencement
conditions after a marine mammal
sighting before or during the activity.
Navy personnel must allow a sighted
marine mammal to leave the mitigation
zone prior to the initial start of the
activity (by delaying the start) or during
the activity (by not recommencing
weapons firing) until one of the
following conditions has been met:
(1) Observed exiting. The animal is
observed exiting the mitigation zone;
(2) Thought to have exited. The
animal is thought to have exited the
mitigation zone based on a
determination of its course, speed, and
movement relative to the firing ship;
(3) Clear from additional sightings.
The mitigation zone has been clear from
any additional sightings for 30 min; or
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
49760
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
(4) Firing ship transit. For mobile
activities, the firing ship has transited a
distance equal to double that of the
mitigation zone size beyond the location
of the last sighting.
(iv) Explosive large-caliber projectiles.
Gunnery activities using explosive
large-caliber projectiles. Mitigation
applies to activities using a surface
target.
(A) Number of Lookouts and
observation platform. One Lookout must
be on the vessel or aircraft conducting
the activity. Depending on the activity,
the Lookout could be the same as the
one described in ‘‘Weapons firing
noise’’ in paragraph (a)(1)(iii)(A) of this
section. If additional platforms are
participating in the activity, Navy
personnel positioned in those assets
(e.g., safety observers, evaluators) must
support observing the mitigation zone
for marine mammals while performing
their regular duties.
(B) Mitigation zones. 1,000 yd (914.4
m) around the intended impact location.
(C) Prior to activity. Prior to the initial
start of the activity (e.g., when
maneuvering on station), Navy
personnel must observe the mitigation
zone for floating vegetation and marine
mammals; if floating vegetation or a
marine mammal is observed, Navy
personnel must relocate or delay the
start of firing until the mitigation zone
is clear of floating vegetation or until the
conditions in paragraph (a)(1)(iv)(E) of
this section are met for marine
mammals.
(D) During activity. During the
activity, Navy personnel must observe
the mitigation zone for marine
mammals; if a marine mammal is
observed, Navy personnel must cease
firing.
(E) Commencement/recommencement
conditions after a marine mammal
sighting before or during the activity.
Navy personnel must allow a sighted
marine mammal to leave the mitigation
zone prior to the initial start of the
activity (by delaying the start) or during
the activity (by not recommencing
firing) until one of the following
conditions has been met:
(1) Observed exiting. The animal is
observed exiting the mitigation zone;
(2) Thought to have exited. The
animal is thought to have exited the
mitigation zone based on a
determination of its course, speed, and
movement relative to the intended
impact location;
(3) Clear of additional sightings. The
mitigation zone has been clear from any
additional sightings for 30 minutes; or,
(4) Impact location transit. For
activities using mobile targets, the
intended impact location has transited a
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
distance equal to double that of the
mitigation zone size beyond the location
of the last sighting.
(F) After activity. After completion of
the activity (e.g., prior to maneuvering
off station), Navy personnel must, when
practical (e.g., when platforms are not
constrained by fuel restrictions or
mission-essential follow-on
commitments), observe for marine
mammals in the vicinity of where
detonations occurred; if any injured or
dead marine mammals are observed,
Navy personnel must follow established
incident reporting procedures. If
additional platforms are supporting this
activity (e.g., providing range clearance),
Navy personnel positioned on these
Navy assets must assist in the visual
observation of the area where
detonations occurred.
(v) Explosive bombs.
(A) Number of Lookouts and
observation platform. One Lookout must
be positioned in an aircraft conducting
the activity. If additional platforms are
participating in the activity, Navy
personnel positioned in those assets
(e.g., safety observers, evaluators) must
support observing the mitigation zone
for marine mammals while performing
their regular duties.
(B) Mitigation zone. 2,500 yd (2,286
m) around the intended target.
(C) Prior to activity. Prior to the initial
start of the activity (e.g., when arriving
on station), Navy personnel must
observe the mitigation zone for floating
vegetation and marine mammals; if
floating vegetation or a marine mammal
is observed, Navy personnel must
relocate or delay the start of bomb
deployment until the mitigation zone is
clear of floating vegetation or until the
conditions in paragraph (a)(1)(v)(E) of
this section are met for marine
mammals.
(D) During activity. During the activity
(e.g., during target approach), Navy
personnel must observe the mitigation
zone for marine mammals; if a marine
mammal is observed, Navy personnel
must cease bomb deployment.
(E) Commencement/recommencement
conditions after a marine mammal
sighting before or during the activity.
Navy personnel must allow a sighted
marine mammal to leave the mitigation
zone prior to the initial start of the
activity (by delaying the start) or during
the activity (by not recommencing bomb
deployment) until one of the following
conditions has been met:
(1) Observed exiting. The animal is
observed exiting the mitigation zone;
(2) Thought to have exited. The
animal is thought to have exited the
mitigation zone based on a
determination of its course, speed, and
PO 00000
Frm 00106
Fmt 4701
Sfmt 4702
movement relative to the intended
target;
(3) Clear from additional sightings.
The mitigation zone has been clear from
any additional sightings for 10 min; or
(4) Intended target transit. For
activities using mobile targets, the
intended target has transited a distance
equal to double that of the mitigation
zone size beyond the location of the last
sighting.
(F) After activity. After completion of
the activity (e.g., prior to maneuvering
off station), Navy personnel must, when
practical (e.g., when platforms are not
constrained by fuel restrictions or
mission-essential follow-on
commitments), observe for marine
mammals in the vicinity of where
detonations occurred; if any injured or
dead marine mammals are observed,
Navy personnel must follow established
incident reporting procedures. If
additional platforms are supporting this
activity (e.g., providing range clearance),
Navy personnel positioned on these
Navy assets must assist in the visual
observation of the area where
detonations occurred.
(vi) Vessel movement. The mitigation
will not be applied if: the vessel’s safety
is threatened; the vessel is restricted in
its ability to maneuver (e.g., during
launching and recovery of aircraft or
landing craft, during towing activities,
when mooring); the vessel is submerged
or operated autonomously; or when
impractical based on mission
requirements (e.g., during Vessel Visit,
Board, Search, and Seizure activities as
military personnel from ships or aircraft
board suspect vessels).
(A) Number of Lookouts and
observation platform. One or more
Lookouts must be on the underway
vessel. If additional watch personnel are
positioned on the underway vessel,
those personnel (e.g., persons assisting
with navigation or safety) must support
observing for marine mammals while
performing their regular duties.
(B) Mitigation zone.
(1) Whales. 500 yd (457.2 m) around
the vessel for whales.
(2) Marine mammals other than
whales. 200 yd (182.9 m) around the
vessel for all marine mammals other
than whales (except those intentionally
swimming alongside or closing in to
swim alongside vessels, such as bowriding or wake-riding dolphins).
(C) When underway. Navy personnel
will observe the direct path of the vessel
and waters surrounding the vessel for
marine mammals. If a marine mammal
is observed in the direct path of the
vessel, Navy personnel will maneuver
the vessel as necessary to maintain the
appropriate mitigation zone distance. If
E:\FR\FM\11AUP2.SGM
11AUP2
lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
a marine mammal is observed within
waters surrounding the vessel, Navy
personnel will maintain situational
awareness of that animal’s position.
Based on the animal’s course and speed
relative to the vessel’s path, Navy
personnel will maneuver the vessel as
necessary to ensure that the appropriate
mitigation zone distance from the
animal continues to be maintained.
(D) Incident reporting procedures. If a
marine mammal vessel strike occurs,
Navy personnel must follow the
established incident reporting
procedures.
(vii) Towed in-water devices.
Mitigation applies to devices that are
towed from a manned surface platform
or manned aircraft, or when a manned
support craft is already participating in
an activity involving in-water devices
being towed by unmanned platforms.
The mitigation will not be applied if the
safety of the towing platform or in-water
device is threatened.
(A) Number of Lookouts and
observation platform. One Lookout must
be positioned on a manned towing
platform or support craft.
(B) Mitigation zone. 250 yd (228.6 m)
around the towed in-water device for
marine mammals (except those
intentionally swimming alongside or
choosing to swim alongside towing
vessels, such as bow-riding or wakeriding dolphins).
(C) During activity. During the activity
(i.e., when towing an in-water device),
Navy personnel must observe the
mitigation zone for marine mammals; if
a marine mammal is observed, Navy
personnel must maneuver to maintain
distance.
(viii) Small-, medium-, and largecaliber non-explosive practice
munitions. Gunnery activities using
small-, medium-, and large-caliber nonexplosive practice munitions. Mitigation
applies to activities using a surface
target.
(A) Number of Lookouts and
observation platform. One Lookout must
be positioned on the platform
conducting the activity. Depending on
the activity, the Lookout could be the
same as the one described for ‘‘Weapons
firing noise’’ in paragraph (a)(1)(iii)(A)
of this section.
(B) Mitigation zone. 200 yd (182.9 m)
around the intended impact location.
(C) Prior to activity. Prior to the initial
start of the activity (e.g., when
maneuvering on station), Navy
personnel must observe the mitigation
zone for floating vegetation and marine
mammals; if floating vegetation or a
marine mammal is observed, Navy
personnel must relocate or delay the
start of firing until the mitigation zone
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
is clear of floating vegetation or until the
conditions in paragraph (a)(1)(viii)(E) of
this section are met for marine
mammals.
(D) During activity. During the
activity, Navy personnel must observe
the mitigation zone for marine
mammals; if a marine mammal is
observed, Navy personnel must cease
firing.
(E) Commencement/recommencement
conditions after a marine mammal
sighting before or during the activity.
Navy personnel must allow a sighted
marine mammal to leave the mitigation
zone prior to the initial start of the
activity (by delaying the start) or during
the activity (by not recommencing
firing) until one of the following
conditions has been met:
(1) Observed exiting. The animal is
observed exiting the mitigation zone;
(2) Thought to have exited. The
animal is thought to have exited the
mitigation zone based on a
determination of its course, speed, and
movement relative to the intended
impact location;
(3) Clear of additional sightings. The
mitigation zone has been clear from any
additional sightings for 10 minutes for
aircraft-based firing or 30 minutes for
vessel-based firing; or
(4) Impact location transit. For
activities using a mobile target, the
intended impact location has transited a
distance equal to double that of the
mitigation zone size beyond the location
of the last sighting.
(ix) Non-explosive bombs. Nonexplosive bombs.
(A) Number of Lookouts and
observation platform. One Lookout must
be positioned in an aircraft.
(B) Mitigation zone. 1,000 yd (914.4
m) around the intended target.
(C) Prior to activity. Prior to the initial
start of the activity (e.g., when arriving
on station), Navy personnel must
observe the mitigation zone for floating
vegetation and marine mammals; if
floating vegetation or a marine mammal
is observed, Navy personnel must
relocate or delay the start of bomb
deployment until the mitigation zone is
clear of floating vegetation or until the
conditions in paragraph (a)(1)(ix)(E) of
this section are met for marine
mammals.
(D) During activity. During the activity
(e.g., during approach of the target),
Navy personnel must observe the
mitigation zone for marine mammals
and, if a marine mammal is observed,
Navy personnel must cease bomb
deployment.
(E) Commencement/recommencement
conditions after a marine mammal
sighting prior to or during the activity.
PO 00000
Frm 00107
Fmt 4701
Sfmt 4702
49761
Navy personnel must allow a sighted
marine mammal to leave the mitigation
zone prior to the initial start of the
activity (by delaying the start) or during
the activity (by not recommencing bomb
deployment) until one of the following
conditions has been met:
(1) Observed exiting. The animal is
observed exiting the mitigation zone;
(2) Thought to have exited. The
animal is thought to have exited the
mitigation zone based on a
determination of its course, speed, and
movement relative to the intended
target;
(3) Clear from additional sightings.
The mitigation zone has been clear from
any additional sightings for 10 min; or
(4) Intended target transit. For
activities using mobile targets, the
intended target has transited a distance
equal to double that of the mitigation
zone size beyond the location of the last
sighting.
(2) Mitigation areas. In addition to
procedural mitigation, Navy personnel
must implement mitigation measures
within mitigation areas to avoid or
reduce potential impacts on marine
mammals.
(i) North Pacific Right Whale
Mitigation Area. Figure 1 shows the
location of the mitigation area.
(A) Surface ship hull-mounted MF1
mid-frequency active sonar. From June
1–September 30 within the North
Pacific Right Whale Mitigation Area,
Navy personnel must not use surface
ship hull-mounted MF1 mid-frequency
active sonar during training.
(B) National security exception.
Should national security require that the
Navy cannot comply with the
restrictions in paragraph (a)(2)(i)(A) of
this section, Navy personnel must
obtain permission from the designated
Command, U.S. Third Fleet Command
Authority, prior to commencement of
the activity. Navy personnel must
provide NMFS with advance
notification and include information
about the event in its annual activity
reports to NMFS.
(ii) Continental Shelf and Slope
Mitigation Area. Figure 1 shows the
location of the mitigation area.
(A) Explosives. Navy personnel must
not detonate explosives below 10,000 ft.
altitude (including at the water surface)
in the Continental Shelf and Slope
Mitigation Area during training.
(B) National security exception.
Should national security require that the
Navy cannot comply with the
restrictions in paragraph (a)(2)(ii)(A) of
this section, Navy personnel must
obtain permission from the designated
Command, U.S. Third Fleet Command
Authority, prior to commencement of
E:\FR\FM\11AUP2.SGM
11AUP2
49762
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
the activity. Navy personnel must
provide NMFS with advance
notification and include information
about the event in its annual activity
reports to NMFS.
(iii) Pre-event Awareness
Notifications in the Temporary Maritime
Activities Area. The Navy must issue
pre-event awareness messages to alert
vessels and aircraft participating in
training activities within the TMAA to
the possible presence of concentrations
of large whales on the continental shelf
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
and slope. Occurrences of large whales
may be higher over the continental shelf
and slope relative to other areas of the
TMAA. Large whale species in the
TMAA include, but are not limited to,
fin whale, blue whale, humpback whale,
gray whale, North Pacific right whale,
sei whale, and sperm whale. To
maintain safety of navigation and to
avoid interactions with marine
mammals, the Navy must instruct
personnel to remain vigilant to the
presence of large whales that may be
PO 00000
Frm 00108
Fmt 4701
Sfmt 4702
vulnerable to vessel strikes or potential
impacts from training activities.
Additionally, Navy personnel must use
the information from the awareness
notification messages to assist their
visual observation of applicable
mitigation zones during training
activities and to aid in the
implementation of procedural
mitigation.
BILLING CODE 3510–22–P
E:\FR\FM\11AUP2.SGM
11AUP2
BILLING CODE 3510–22–C
lotter on DSK11XQN23PROD with PROPOSALS2
(b) [Reserved]
§ 218.155 Requirements for monitoring
and reporting.
(a) Unauthorized take. Navy
personnel must notify NMFS
immediately (or as soon as operational
security considerations allow) if the
specified activity identified in § 218.150
is thought to have resulted in the
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
mortality or serious injury of any marine
mammals, or in any Level A harassment
or Level B harassment of marine
mammals not authorized under this
subpart.
(b) Monitoring and reporting under
the LOA. The Navy must conduct all
monitoring and reporting required
under the LOA, including abiding by
the U.S. Navy’s Marine Species
PO 00000
Frm 00109
Fmt 4701
Sfmt 4702
49763
Monitoring Program. Details on program
goals, objectives, project selection
process, and current projects are
available at
www.navymarinespeciesmonitoring.us.
(c) Notification of injured, live
stranded, or dead marine mammals.
Navy personnel must consult the
Notification and Reporting Plan, which
sets out notification, reporting, and
E:\FR\FM\11AUP2.SGM
11AUP2
EP11AU22.005</GPH>
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
lotter on DSK11XQN23PROD with PROPOSALS2
49764
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
other requirements when dead, injured,
or live stranded marine mammals are
detected. The Notification and
Reporting Plan is available at https://
www.fisheries.noaa.gov/national/
marine-mammal-protection/incidentaltake-authorizations-military-readinessactivities.
(d) Annual GOA Marine Species
Monitoring Report. The Navy must
submit an annual report of the GOA
Study Area monitoring, which will be
included in a Pacific-wide monitoring
report and include results specific to the
GOA Study Area, describing the
implementation and results from the
previous calendar year. Data collection
methods must be standardized across
Pacific Range Complexes including the
Mariana Islands Training and Testing
(MITT), Hawaii-Southern California
Training and Testing (HSTT), Northwest
Training and Testing (NWTT), and Gulf
of Alaska (GOA) Study Areas to allow
for comparison among different
geographic locations. The report must
be submitted to the Director, Office of
Protected Resources, NMFS, either
within 3 months after the end of the
calendar year, or within 3 months after
the conclusion of the monitoring year,
to be determined by the adaptive
management process. NMFS will submit
comments or questions on the report, if
any, within 3 months of receipt. The
report will be considered final after the
Navy has addressed NMFS’ comments,
or 3 months after submittal if NMFS
does not provide comments on the
report. This report will describe
progress of knowledge made with
respect to intermediate scientific
objectives within the GOA Study Area
associated with the Integrated
Comprehensive Monitoring Program
(ICMP). Similar study questions must be
treated together so that progress on each
topic can be summarized across all
Navy ranges. The report need not
include analyses and content that does
not provide direct assessment of
cumulative progress on the monitoring
plan study questions. This will continue
to allow the Navy to provide a cohesive
monitoring report covering multiple
ranges (as per ICMP goals), rather than
entirely separate reports for the GOA,
NWTT, HSTT, and MITT Study Areas.
(e) GOA Annual Training Report.
Each year in which training activities
are conducted in the GOA Study Area,
the Navy must submit one preliminary
report (Quick Look Report) to NMFS
detailing the status of applicable sound
sources within 21 days after the
completion of the training activities in
the GOA Study Area. Each year in
which activities are conducted, the
Navy must also submit a detailed report
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
(GOA Annual Training Report) to the
Director, Office of Protected Resources,
NMFS, within 3 months after
completion of the training activities.
NMFS must submit comments or
questions on the report, if any, within
one month of receipt. The report will be
considered final after the Navy has
addressed NMFS’ comments, or one
month after submittal if NMFS does not
provide comments on the report. The
annual reports must contain information
about the Major Training Exercise
(MTE), including the information listed
in paragraphs (e)(1) and (2) of this
section. The annual report, which is
only required during years in which
activities are conducted, must also
contain cumulative sonar and explosive
use quantity from previous years’
reports through the current year.
Additionally, if there were any changes
to the sound source allowance in the
reporting year, or cumulatively, the
report must include a discussion of why
the change was made and include
analysis to support how the change did
or did not affect the analysis in the GOA
SEIS/OEIS and MMPA final rule. The
analysis in the detailed report must be
based on the accumulation of data from
the current year’s report and data
collected from previous annual reports.
The final annual/close-out report at the
conclusion of the authorization period
(year seven) will also serve as the
comprehensive close-out report and
include both the final year annual use
compared to annual authorization as
well as a cumulative 7-year annual use
compared to 7-year authorization. This
report must also note any years in
which training did not occur. NMFS
must submit comments on the draft
close-out report, if any, within 3 months
of receipt. The report will be considered
final after the Navy has addressed
NMFS’ comments, or 3 months after the
submittal if NMFS does not provide
comments. Information included in the
annual reports may be used to inform
future adaptive management of
activities within the GOA Study Area.
In addition to the information discussed
above, the GOA Annual Training Report
must include the following information.
(1) MFAS/HFAS. The Navy must
submit the following information for the
MTE conducted in the GOA Study Area.
(i) Exercise Information (for each
MTE):
(A) Exercise designator.
(B) Date that exercise began and
ended.
(C) Location.
(D) Number and types of active
sources used in the exercise.
(E) Number and types of passive
acoustic sources used in exercise.
PO 00000
Frm 00110
Fmt 4701
Sfmt 4702
(F) Number and types of vessels,
aircraft, etc., participating in exercise.
(G) Total hours of observation by
Lookouts.
(H) Total hours of all active sonar
source operation.
(I) Total hours of each active sonar
source bin.
(J) Wave height (high, low, and
average during exercise).
(ii) Individual marine mammal
sighting information for each sighting in
each exercise where mitigation was
implemented:
(A) Date/Time/Location of sighting.
(B) Species (if not possible, indication
of whale/dolphin/pinniped).
(C) Number of individuals.
(D) Initial Detection Sensor (e.g.,
sonar or Lookout).
(E) Indication of specific type of
platform observation made from
(including, for example, what type of
surface vessel or testing platform).
(F) Length of time observers
maintained visual contact with marine
mammal.
(G) Sea state.
(H) Visibility.
(I) Sound source in use at the time of
sighting.
(J) Indication of whether animal was
less than 200 yd (182.9 m), 200 to 500
yd (182.9 to 457.2 m), 500 to 1,000 yd
(457.2 to 914.4 m), 1,000 to 2,000 yd
(914.4 to 1,828.8 m), or greater than
2,000 yd (1,828.8 m) from sonar source.
(K) Sonar mitigation implementation.
Whether operation of sonar sensor was
delayed, or sonar was powered or shut
down, and how long the delay was.
(L) Bearing, direction, and motion. If
source in use is hull-mounted, true
bearing of animal from ship, true
direction of ship’s travel, and estimation
of animal’s motion relative to ship
(opening, closing, parallel).
(M) Observed behavior. Lookouts
shall report, in plain language and
without trying to categorize in any way,
the observed behavior of the animals
(such as animal closing to bow ride,
paralleling course/speed, floating on
surface and not swimming, etc.) and if
any calves present.
(iii) Mitigation effectiveness
evaluation. An evaluation (based on
data gathered during all of the MTEs) of
the effectiveness of mitigation measures
designed to minimize the received level
to which marine mammals may be
exposed. This evaluation shall identify
the specific observations that support
any conclusions the Navy reaches about
the effectiveness of the mitigation.
(2) Summary of sources used. (i) This
section shall include the following
information summarized from the
authorized sound sources used in all
training events:
E:\FR\FM\11AUP2.SGM
11AUP2
Federal Register / Vol. 87, No. 154 / Thursday, August 11, 2022 / Proposed Rules
(A) Total hours. Total annual hours or
quantity (per the LOA) of each bin of
sonar or other non-impulsive source;
and
(B) Number of explosives. Total
annual number of each type of explosive
exercises and total annual expended/
detonated rounds (bombs, large-caliber
projectiles) for each explosive bin.
§ 218.156
Letters of Authorization.
lotter on DSK11XQN23PROD with PROPOSALS2
(a) To incidentally take marine
mammals pursuant to this subpart, the
Navy must apply for and obtain an LOA
in accordance with § 216.106 of this
chapter.
(b) An LOA, unless suspended or
revoked, may be effective for a period of
time not to exceed the expiration date
of this subpart.
(c) If an LOA expires prior to the
expiration date of this subpart, the Navy
may apply for and obtain a renewal of
the LOA.
(d) In the event of projected changes
to the activity or to mitigation,
monitoring, or reporting (excluding
changes made pursuant to the adaptive
management provision of
§ 218.157(c)(1)) required by an LOA
issued under this subpart, the Navy
must apply for and obtain a
modification of the LOA as described in
§ 218.157.
(e) Each LOA will set forth:
(1) Permissible methods of incidental
taking;
(2) Geographic areas for incidental
taking;
(3) Means of effecting the least
practicable adverse impact (i.e.,
mitigation) on the species and stocks of
marine mammals and their habitat; and
(4) Requirements for monitoring and
reporting.
(f) Issuance of the LOA will be based
on a determination that the level of
VerDate Sep<11>2014
18:10 Aug 10, 2022
Jkt 256001
taking is consistent with the findings
made for the total taking allowable
under this subpart.
(g) Notice of issuance or denial of the
LOA will be published in the Federal
Register within 30 days of a
determination.
§ 218.157 Renewals and modifications of
Letters of Authorization.
(a) An LOA issued under §§ 216.106
of this chapter and 218.156 for the
activity identified in § 218.150(c) may
be renewed or modified upon request by
the applicant, provided that:
(1) The planned specified activity and
mitigation, monitoring, and reporting
measures, as well as the anticipated
impacts, are the same as those described
and analyzed for this subpart (excluding
changes made pursuant to the adaptive
management provision in paragraph
(c)(1) of this section); and
(2) NMFS determines that the
mitigation, monitoring, and reporting
measures required by the previous LOA
were implemented.
(b) For LOA modification or renewal
requests by the applicant that include
changes to the activity or to the
mitigation, monitoring, or reporting
measures (excluding changes made
pursuant to the adaptive management
provision in paragraph (c)(1) of this
section) that do not change the findings
made for this subpart or result in no
more than a minor change in the total
estimated number of takes (or
distribution by species or stock or
years), NMFS may publish a notice of
planned LOA in the Federal Register,
including the associated analysis of the
change, and solicit public comment
before issuing the LOA.
(c) An LOA issued under §§ 216.106
of this chapter and 218.156 may be
PO 00000
Frm 00111
Fmt 4701
Sfmt 9990
49765
modified by NMFS under the following
circumstances:
(1) After consulting with the Navy
regarding the practicability of the
modifications, NMFS may modify
(including adding or removing
measures) the existing mitigation,
monitoring, or reporting measures if
doing so creates a reasonable likelihood
of more effectively accomplishing the
goals of the mitigation and monitoring.
(i) Possible sources of data that could
contribute to the decision to modify the
mitigation, monitoring, or reporting
measures in an LOA include:
(A) Results from the Navy’s
monitoring from the previous year(s);
(B) Results from other marine
mammal and/or sound research or
studies; or
(C) Any information that reveals
marine mammals may have been taken
in a manner, extent, or number not
authorized by this subpart or a
subsequent LOA.
(ii) If, through adaptive management,
the modifications to the mitigation,
monitoring, or reporting measures are
substantial, NMFS will publish a notice
of planned LOA in the Federal Register
and solicit public comment.
(2) If NMFS determines that an
emergency exists that poses a significant
risk to the well-being of the species or
stocks of marine mammals specified in
LOAs issued pursuant to §§ 216.106 of
this chapter and 218.156, an LOA may
be modified without prior notice or
opportunity for public comment. Notice
would be published in the Federal
Register within 30 days of the action.
§ 218.158
[Reserved]
[FR Doc. 2022–16509 Filed 8–10–22; 8:45 am]
BILLING CODE 3510–22–P
E:\FR\FM\11AUP2.SGM
11AUP2
]]>Agencies
[Federal Register Volume 87, Number 154 (Thursday, August 11, 2022)]
[Proposed Rules]
[Pages 49656-49765]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-16509]
[[Page 49655]]
Vol. 87
Thursday,
No. 154
August 11, 2022
Part II
Department of Commerce
-----------------------------------------------------------------------
National Oceanic and Atmospheric Administration
-----------------------------------------------------------------------
50 CFR Part 218
Taking and Importing Marine Mammals; Taking Marine Mammals Incidental
to the U.S. Navy Training Activities in the Gulf of Alaska Study Area;
Proposed Rule
Federal Register / Vol. 87 , No. 154 / Thursday, August 11, 2022 /
Proposed Rules
[[Page 49656]]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 218
[Docket No. 220726-0163]
RIN 0648-BK46
Taking and Importing Marine Mammals; Taking Marine Mammals
Incidental to the U.S. Navy Training Activities in the Gulf of Alaska
Study Area
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Proposed rule; request for comments and information.
-----------------------------------------------------------------------
SUMMARY: NMFS has received a request from the U.S. Navy (Navy) to take
marine mammals incidental to training activities conducted in the Gulf
of Alaska (GOA) Study Area (hereafter referred to as the GOA Study
Area). Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is
requesting comments on its proposal to issue regulations and a
subsequent Letter of Authorization (LOA) to the Navy to incidentally
take marine mammals during the specified activities. NMFS will consider
public comments prior to issuing any final rule and making final
decisions on the issuance of the requested LOA. Agency responses to
public comments will be provided in the notice of the final decision.
The Navy's activities qualify as military readiness activities pursuant
to the MMPA, as amended by the National Defense Authorization Act for
Fiscal Year 2004 (2004 NDAA).
DATES: Comments and information must be received no later than
September 26, 2022.
ADDRESSES: Submit all electronic public comments via the Federal e-
Rulemaking Portal. Go to https://www.regulations.gov and enter NOAA-
NMFS-2022-0060 in the Search box. Click on the ``Comment'' icon,
complete the required fields, and enter or attach your comments.
Instructions: Comments sent by any other method, to any other
address or individual, or received after the end of the comment period,
may not be considered by NMFS. All comments received are a part of the
public record and will generally be posted for public viewing on
www.regulations.gov without change. All personal identifying
information (e.g., name, address), confidential business information,
or otherwise sensitive information submitted voluntarily by the sender
will be publicly accessible. NMFS will accept anonymous comments (enter
``N/A'' in the required fields if you wish to remain anonymous).
Attachments to electronic comments will be accepted in Microsoft Word,
Excel, or Adobe PDF file formats only.
A copy of the Navy's application and other supporting documents and
documents cited herein may be obtained online at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-navy-training-activities-gulf-alaska-temporary-maritime-0. In case of
problems accessing these documents, please use the contact listed here
(see FOR FURTHER INFORMATION CONTACT).
FOR FURTHER INFORMATION CONTACT: Leah Davis, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Purpose of Regulatory Action
These proposed regulations, issued under the authority of the MMPA
(16 U.S.C. 1361 et seq.), would provide the framework for authorizing
the take of marine mammals incidental to the Navy's training activities
(which qualify as military readiness activities), including the use of
sonar and other transducers, and in-air detonations at or near the
surface (within 10 m above the water surface) in the GOA Study Area.
The GOA Study Area is comprised of three areas: the Temporary Maritime
Activities Area (TMAA), a warning area, and the Western Maneuver Area
(WMA) (see Figure 1). The TMAA and WMA are temporary areas established
within the GOA for ships, submarines, and aircraft to conduct training
activities. The warning area overlaps and extends slightly beyond the
northern corner of the TMAA. The WMA is located south and west of the
TMAA and provides additional surface, sub-surface, and airspace in
which to maneuver in support of activities occurring within the TMAA.
The use of sonar and other transducers, and explosives would not occur
within the WMA.
NMFS received an application from the Navy requesting 7-year
regulations and an authorization to incidentally take individuals of
multiple species of marine mammals (``Navy's rulemaking/LOA
application'' or ``Navy's application''). Take is anticipated to occur
by Level A harassment and Level B harassment incidental to the Navy's
training activities. No lethal take is anticipated or proposed for
authorization.
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA direct the
Secretary of Commerce (as delegated to NMFS) to allow, upon request,
the incidental, but not intentional, taking of small numbers of marine
mammals by U.S. citizens who engage in a specified activity (other than
commercial fishing) within a specified geographical region if certain
findings are made and either regulations are proposed or, if the taking
is limited to harassment, the public is provided with notice of the
proposed incidental take authorization and provided the opportunity to
review and submit comments.
An authorization for incidental takings shall be granted if NMFS
finds that the taking will have a negligible impact on the species or
stocks and will not have an unmitigable adverse impact on the
availability of the species or stocks for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other means of effecting the least practicable adverse
impact on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of such species or stocks for
taking for certain subsistence uses (referred to in this rule as
``mitigation measures''); and requirements pertaining to the monitoring
and reporting of such takings. The MMPA defines ``take'' to mean to
harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or
kill any marine mammal. The Preliminary Analysis and Negligible Impact
Determination section below discusses the definition of ``negligible
impact.''
The NDAA for Fiscal Year 2004 (2004 NDAA) (Pub. L. 108-136) amended
section 101(a)(5) of the MMPA to remove the ``small numbers'' and
``specified geographical region'' provisions indicated above and
amended the definition of ``harassment'' as applied to a ``military
readiness activity.'' The definition of harassment for military
readiness activities (Section 3(18)(B) of the MMPA) is (i) Any act that
injures or has the significant potential to injure a marine mammal or
marine mammal stock in the wild (Level A Harassment); or (ii) Any act
that disturbs or is likely to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of natural behavioral patterns,
including, but not limited to, migration, surfacing, nursing, breeding,
feeding, or sheltering, to a
[[Page 49657]]
point where such behavioral patterns are abandoned or significantly
altered (Level B harassment). In addition, the 2004 NDAA amended the
MMPA as it relates to military readiness activities such that the least
practicable adverse impact analysis shall include consideration of
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
More recently, Section 316 of the NDAA for Fiscal Year 2019 (2019
NDAA) (Pub. L. 115-232), signed on August 13, 2018, amended the MMPA to
allow incidental take rules for military readiness activities under
section 101(a)(5)(A) to be issued for up to 7 years. Prior to this
amendment, all incidental take rules under section 101(a)(5)(A) were
limited to 5 years.
Summary and Background of Request
On October 9, 2020, NMFS received an adequate and complete
application from the Navy requesting authorization for take of marine
mammals, by Level A harassment and Level B harassment, incidental to
training from the use of active sonar and other transducers and
explosives (in-air, occurring at or above the water surface) in the
TMAA over a 7-year period beginning when the current authorization
expires. On March 12, 2021, the Navy submitted an updated application
that provided revisions to the Northern fur seal take estimate and
incorporated additional best available science. In August 2021, the
Navy communicated to NMFS that it was considering an expansion of the
GOA Study Area and an expansion of the Portlock Bank Mitigation Area
proposed in its previous applications. On February 2, 2022, the Navy
submitted a second updated application that described the addition of
the WMA to the GOA Study Area (which previously just consisted of the
TMAA) and the replacement of the Portlock Bank Mitigation Area with the
Continental Shelf and Slope Mitigation Area. The Navy is not planning
to conduct any testing activities.
On January 8, 2021 (86 FR 1483), we published a notice of receipt
(NOR) of application in the Federal Register, requesting comments and
information related to the Navy's request for 30 days. We received one
comment on the NOR that was non-substantive in nature.
The following types of training, which are classified as military
readiness activities pursuant to the MMPA, as amended by the 2004 NDAA,
would be covered under the regulations and LOA (if issued): surface
warfare (detonations at or above the water surface) and anti-submarine
warfare (sonar and other transducers). The Navy is also conducting Air
Warfare, Electronic Warfare, Naval Special Warfare, Strike Warfare, and
Support Operations, but these activities do not involve sonar and other
transducers, detonations at or above the water surface, or any other
stressors that could result in the take of marine mammals. (See the
2020 GOA Draft SEIS/OEIS for more detail on those activities). The
activities would not include in-water explosives, pile driving/removal,
or use of air guns.
This would be the third time NMFS has promulgated incidental take
regulations pursuant to the MMPA relating to similar military readiness
activities in the GOA, following those effective beginning May 4, 2011
(76 FR 25479; May 4, 2011) and April 26, 2017 (82 FR 19530; April 27,
2017).
The Navy's mission is to organize, train, equip, and maintain
combat-ready naval forces capable of winning wars, deterring
aggression, and maintaining freedom of the seas. This mission is
mandated by Federal law (10 U.S.C. 8062), which requires the readiness
of the naval forces of the United States. The Navy executes this
responsibility by establishing and executing training programs,
including at-sea training and exercises, and ensuring naval forces have
access to the ranges, operating areas (OPAREA), and airspace needed to
develop and maintain skills for conducting naval activities.
The Navy has conducted training activities in the TMAA portion of
the GOA Study Area since the 1990s. Since the 1990s, the Department of
Defense has conducted a major joint training exercise in Alaska and off
the Alaskan coast that involves the Departments of the Navy, Army, Air
Force, and Coast Guard participants reporting to a unified or joint
commander who coordinates the activities. These activities are planned
to demonstrate and evaluate the ability of the services to engage in a
conflict and successfully carry out plans in response to a threat to
national security. The Navy's planned activities for the period of this
proposed rule would be a continuation of the types and level of
training activities that have been ongoing for more than a decade.
While the specified activities have not changed, there are changes in
the platforms and systems used in those activities, as well as changes
in the bins (source classifications) used to analyze the activities.
(For example, two new sonar bins were added (MF12 and ASW1) and another
bin was eliminated (HF6). This was due to changes in platforms and
systems.) Further, the Navy expanded the GOA Study Area to include the
WMA, though the vast majority of the training activities would still
occur only in the TMAA.
The Navy's rulemaking/LOA application reflects the most up-to-date
compilation of training activities deemed necessary by senior Navy
leadership to accomplish military readiness requirements. The types and
numbers of activities included in the proposed rule account for
fluctuations in training in order to meet evolving or emergent military
readiness requirements. These proposed regulations would become
effective in December of 2022 and would cover training activities that
would occur for a 7-year period following the expiration of the current
MMPA authorization for the GOA, which expired on April 26, 2022.
Description of the Specified Activity
The Navy requests authorization to take marine mammals incidental
to conducting training activities. The Navy has determined that
acoustic and explosives stressors are most likely to result in impacts
on marine mammals that could rise to the level of harassment, and NMFS
concurs with this determination. Detailed descriptions of these
activities are provided in Chapter 2 of the 2020 GOA Draft Supplemental
Environmental Impact Statement (SEIS)/Overseas EIS (OEIS) (2020 GOA
DSEIS/OEIS) (https://www.goaeis.com/) and in the Navy's rulemaking/LOA
application (https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-navy-training-activities-gulf-alaska-temporary-maritime-0) and are summarized here.
Dates and Duration
Training activities would be conducted intermittently in the GOA
Study Area over a maximum time period of up to 21 consecutive days
annually from April to October to support a major joint training
exercise in Alaska and off the Alaskan coast that involves the
Departments of the Navy, Army, Air Force, and Coast Guard. The
participants report to a unified or joint commander who coordinates the
activities planned to demonstrate and evaluate the ability of the
services to engage in a conflict and carry out plans in response to a
threat to national security. The specified activities would occur over
a maximum time period of up to 21 consecutive days each year during the
7-year period of validity of the regulations. The proposed number of
training activities are described in the Detailed Description of
Proposed Activities section (Table 3) of this proposed rule.
[[Page 49658]]
Geographical Region
The GOA Study Area (see Figure 1 below and Figure ES-1 of the 2022
Supplement to the 2020 GOA DSEIS/OEIS) is entirely at sea and is
comprised of the TMAA and a warning area in the Gulf of Alaska, and the
WMA. The term ``at-sea'' refers to training activities in the Study
Area (both the TMAA and WMA) that occur (1) on the ocean surface, (2)
beneath the ocean surface, and (3) in the air above the ocean surface.
Navy training activities occurring on or over the land outside the GOA
Study Area are not included in this proposed rule, and are covered
under separate environmental documentation prepared by the U.S. Air
Force and the U.S. Army. As depicted in Figure 1 of this proposed rule,
the TMAA is a polygon roughly resembling a rectangle oriented from
northwest to southeast, approximately 300 nmi (556 km) in length by 150
nmi (278 km) in width, located south of Montague Island and east of
Kodiak Island. The GOA Study Area boundary was intentionally designed
to avoid ESA-designated Steller sea lion critical habitat. The WMA is
located south and west of the TMAA, and provides an additional 185,806
nmi\2\ of surface, sub-surface, and airspace training to support
activities occurring within the TMAA (Figure 1). The boundary of the
WMA follows the bottom of the slope at the 4,000 m contour line, and
was configured to avoid overlap and impacts to ESA-designated critical
habitat, biologically important areas (BIAs), migration routes, and
primary fishing grounds. The WMA provides additional airspace and sea
space for aircraft and vessels to maneuver during training activities
for increased training complexity. The TMAA and WMA are temporary areas
established within the GOA for ships, submarines, and aircraft to
conduct training activities.
Additional detail can be found in Chapter 2 of the Navy's
rulemaking/LOA application.
BILLING CODE 3510-22-P
[[Page 49659]]
[GRAPHIC] [TIFF OMITTED] TP11AU22.000
BILLING CODE 3510-22-C
[[Page 49660]]
Primary Mission Areas
The Navy categorizes many of its training activities into
functional warfare areas called primary mission areas. The Navy's
planned activities for the GOA Study Area generally fall into the
following six primary mission areas: Air Warfare; Surface Warfare;
Anti-Submarine Warfare; Electronic Warfare; Naval Special Warfare; and
Strike Warfare. Most activities conducted in the GOA are categorized
under one of these primary mission areas; activities that do not fall
within one of these areas are listed as ``support operations'' or
``other training activities.'' Each warfare community (aviation,
surface, and subsurface) may train in some or all of these primary
mission areas. A description of the sonar, munitions, targets, systems,
and other materials used during training activities within these
primary mission areas is provided in Appendix A (Navy Activities
Descriptions) of the 2020 GOA DSEIS/OEIS and section ES.2.2 (Proposed
Activities in the Western Maneuver Area) of the 2022 Supplement to the
2020 GOA DSEIS/OEIS.
The Navy describes and analyzes the effects of its training
activities within the 2020 GOA DSEIS/OEIS and 2022 Supplement to the
2020 GOA DSEIS/OEIS. In its assessment, the Navy concluded that of the
activities to be conducted within the GOA Study Area, sonar use and in-
air explosives occurring at or above the water surface were the
stressors resulting in impacts on marine mammals that could rise to the
level of harassment as defined under the MMPA. (The Navy is not
proposing to conduct any activities that use in-water or underwater
explosives.) Further, these activities are limited to the TMAA. No
activities involving sonar use or explosives would occur in the WMA or
the portion of the warning area that extends beyond the TMAA.
Therefore, the Navy's rulemaking/LOA application provides the Navy's
assessment of potential effects from sonar use and explosives occurring
at or above the water surface in terms of the various warfare mission
areas they are associated with. Those mission areas include the
following:
surface warfare (in-air detonations at or above the water
surface); \1\ and
---------------------------------------------------------------------------
\1\ Defined herein as being within 10 meters of the ocean
surface.
---------------------------------------------------------------------------
anti-submarine warfare (sonar and other transducers).
The Navy's activities in Air Warfare, Electronic Warfare, Naval
Special Warfare, Strike Warfare, Support Operations, and Other Training
Activities do not involve sonar and other transducers, detonations at
or near the surface, or any other stressors that could result in
harassment, serious injury, or mortality of marine mammals. Therefore,
the activities in these warfare areas are not discussed further in this
proposed rule, but are analyzed fully in the 2020 GOA DSEIS/OEIS and
2022 Supplement to the 2020 GOA DSEIS/OEIS. The specific acoustic
sources analyzed in this proposed rule are contained in the 2020 GOA
DSEIS/OEIS and are presented in the following sections based on the
primary mission areas.
Surface Warfare
The mission of surface warfare (named anti-surface warfare in the
2011 GOA Final Environmental Impact Statement (FEIS)/Overseas
Environmental Impact Statement (OEIS) and 2016 GOA Final Supplemental
Environmental Impact Statement (FSEIS)/OEIS, but since changed by the
Navy to ``Surface Warfare'') is to obtain control of sea space from
which naval forces may operate, which entails offensive action against
surface targets while also defending against enemy forces. In surface
warfare, aircraft use guns, air-launched cruise missiles, or other
precision-guided munitions; ships employ naval guns and surface-to-
surface missiles; and submarines attack surface ships using anti-ship
cruise missiles.
Anti-Submarine Warfare
The mission of anti-submarine warfare is to locate, neutralize, and
defeat hostile submarine forces that threaten Navy surface forces.
Anti-submarine warfare can involve various assets such as aircraft,
ships, and submarines which all search for hostile submarines. These
forces operate together or independently to gain early warning and
detection, and to localize, track, target, and attack submarine
threats.
Anti-submarine warfare training addresses basic skills such as
detecting and classifying submarines, as well as evaluating sounds to
distinguish between enemy submarines and friendly submarines, ships,
and marine life. These integrated anti-submarine warfare training
exercises are conducted in coordinated, at-sea training events
involving submarines, ships, and aircraft.
Overview of the Major Training Exercise Within the GOA Study Area
The training activities in the GOA Study Area are considered to be
a major training exercise (MTE). A MTE, for purposes of this
rulemaking, is comprised of several unit-level activities conducted by
several units operating together, commanded and controlled by a single
Commander, and potentially generating more than 100 hours of active
sonar. These exercises typically employ an exercise scenario developed
to train and evaluate the exercise participants in tactical and
operational tasks. In a MTE, most of the activities being directed and
coordinated by the Commander in charge of the exercise are identical in
nature to the activities conducted during individual, crew, and smaller
unit-level training events. In a MTE, however, these disparate training
tasks are conducted in concert, rather than in isolation. At most, only
one MTE would occur in the GOA Study Area per year (over a maximum of
21 days).
Description of Stressors
The Navy uses a variety of sensors, platforms, weapons, and other
devices, including ones used to ensure the safety of Sailors and
Marines, to meet its mission. Training with these systems may introduce
sound and energy into the environment. The proposed training activities
were evaluated to identify specific components that could act as
stressors by having direct or indirect impacts on the environment. This
analysis included identification of the spatial variation of the
identified stressors. The following subsections describe the acoustic
and explosive stressors for marine mammals and their habitat (including
prey species) within the GOA Study Area. Each description contains a
list of activities that may generate the stressor. Stressor/resource
interactions that were determined to have de minimis or no impacts
(e.g., vessel noise, aircraft noise, weapons noise, and high-altitude
(greater than 10 m above the water surface) explosions) were not
carried forward for analysis in the Navy's rulemaking/LOA application.
The Navy fully considered the possibility of vessel strike, conducted
an analysis, and determined that requesting take of marine mammals by
vessel strike was not warranted. Although the Navy did not request take
for vessel strike, NMFS also fully analyzed the potential for vessel
strike of marine mammals as part of this rulemaking. Therefore, this
stressor is discussed in detail below. No Sinking Exercise (SINKEX)
events are proposed in the GOA Study Area for this rulemaking, nor is
establishment and use of a Portable Undersea Tracking Range (PUTR)
proposed. NMFS reviewed the Navy's analysis and conclusions on de
minimis and no-impact sources, included in Section 3.8.3 (Environmental
Consequences) of
[[Page 49661]]
the 2020 GOA DSEIS/OEIS and finds them complete and supportable.
Acoustic Stressors
Acoustic stressors include acoustic signals emitted into the water
for a specific purpose, such as sonar, other transducers (devices that
convert energy from one form to another--in this case, into sound
waves), incidental sources of broadband sound produced as a byproduct
of vessel movement, aircraft transits, and use of weapons or other
deployed objects. Explosives also produce broadband sound but are
characterized separately from other acoustic sources due to their
unique hazardous characteristics. Characteristics of each of these
sound sources are described in the following sections.
In order to better organize and facilitate the analysis of
approximately 300 sources of underwater sound used by the Navy,
including sonar and other transducers and explosives, a series of
source classifications, or source bins, were developed. The source
classification bins do not include the broadband noise produced
incidental to vessel movement, aircraft transits, and weapons firing.
Noise produced from vessel movement, aircraft transits, and use of
weapons or other deployed objects is not carried forward because those
activities were found to have de minimis or no impacts, as described
above.
The use of source classification bins provides the following
benefits:
Provides the ability for new sensors or munitions to be
covered under existing authorizations, as long as those sources fall
within the parameters of a ``bin;''
Improves efficiency of source utilization data collection
and reporting requirements anticipated under the MMPA authorizations;
Ensures a precautionary approach to all impact estimates,
as all sources within a given class are modeled as the most impactful
source (highest source level, longest duty cycle, or largest net
explosive weight) within that bin;
Allows analyses to be conducted in a more efficient
manner, without any compromise of analytical results; and
Provides a framework to support the reallocation of source
usage (hours/explosives) between different source bins, as long as the
total numbers of takes remain within the overall analyzed and
authorized limits. This flexibility is required to support evolving
Navy training and testing requirements, which are linked to real world
events.
Sonar and Other Transducers
Active sonar and other transducers emit non-impulsive sound waves
into the water to detect objects, navigate safely, and communicate.
Passive sonars differ from active sound sources in that they do not
emit acoustic signals; rather, they only receive acoustic information
about the environment, or listen. In this proposed rule, the terms
sonar and other transducers will be used to indicate active sound
sources unless otherwise specified.
The Navy employs a variety of sonars and other transducers to
obtain and transmit information about the undersea environment. Some
examples are mid-frequency hull-mounted sonars used to find and track
enemy submarines; high-frequency small object detection sonars used to
detect mines; high-frequency underwater modems used to transfer data
over short ranges; and extremely high-frequency (greater than 200
kilohertz (kHz)) doppler sonars used for navigation, like those used on
commercial and private vessels. The characteristics of these sonars and
other transducers, such as source level, beam width, directivity, and
frequency, depend on the purpose of the source. Higher frequencies can
carry more information or provide more information about objects off
which they reflect, but attenuate more rapidly. Lower frequencies
attenuate less rapidly, so they may detect objects over a longer
distance, but with less detail.
Propagation of sound produced underwater is highly dependent on
environmental characteristics such as bathymetry, bottom type, water
depth, temperature, and salinity. The sound received at a particular
location will be different than near the source due to the interaction
of many factors, including propagation loss; how the sound is
reflected, refracted, or scattered; the potential for reverberation;
and interference due to multi-path propagation. In addition, absorption
greatly affects the distance over which higher-frequency sounds
propagate. The effects of these factors are explained in Appendix B
(Acoustic and Explosive Concepts) of the 2020 GOA DSEIS/OEIS. Because
of the complexity of analyzing sound propagation in the ocean
environment, the Navy relies on acoustic models in its environmental
analyses that consider sound source characteristics and varying ocean
conditions across the TMAA. As noted above, the Navy does not propose
to use sonar and other transducers within the WMA.
The sound sources and platforms typically used in naval activities
analyzed in the Navy's rulemaking/LOA application are described in
Appendix A (Navy Activities Descriptions) of the 2020 GOA DSEIS/OEIS.
Sonars and other transducers used to obtain and transmit information
underwater during Navy training activities generally fall into several
categories of use described below.
Anti-Submarine Warfare
Sonar used during anti-submarine warfare would impart the greatest
amount of acoustic energy of any category of sonar and other
transducers analyzed in this proposed rule. Types of sonars used to
detect potential enemy vessels include hull-mounted, towed, line array,
sonobuoy, and helicopter dipping sonars. In addition, acoustic targets
and decoys (countermeasures) may be deployed to emulate the sound
signatures of vessels or repeat received signals.
Most anti-submarine warfare sonars are mid-frequency (1-10 kHz)
because mid-frequency sound balances sufficient resolution to identify
targets with distance over which threats can be identified. However,
some sources may use higher or lower frequencies. Duty cycles can vary
widely, from rarely used to continuously active. For example, anti-
submarine warfare sonars can be wide angle in a search mode or highly
directional in a track mode.
Most anti-submarine warfare activities involving submarines or
submarine targets would occur in waters greater than 600 feet (ft; 183
m) deep due to safety concerns about running aground at shallower
depths.
Navigation and Safety
Similar to commercial and private vessels, Navy vessels employ
navigational acoustic devices, including speed logs, Doppler sonars for
ship positioning, and fathometers. These may be in use at any time for
safe vessel operation. These sources are typically highly directional
to obtain specific navigational data.
Communication
Sound sources used to transmit data (such as underwater modems),
provide location (pingers), or send a single brief release signal to
bottom-mounted devices (acoustic release) may be used throughout the
TMAA. These sources typically have low duty cycles and are usually only
used when it is desirable to send a detectable acoustic message.
Classification of Sonar and Other Transducers
Sonars and other transducers are grouped into classes that share an
[[Page 49662]]
attribute, such as frequency range or purpose. As detailed below,
classes are further sorted by bins based on the frequency or bandwidth;
source level; and, when warranted, the application for which the source
would be used. Unless stated otherwise, a reference distance of 1 meter
(m) is used for sonar and other transducers.
Frequency of the non-impulsive acoustic source:
[cir] Low-frequency sources operate below 1 kHz;
[cir] Mid-frequency sources operate at and above 1 kHz, up to and
including 10 kHz;
[cir] High-frequency sources operate above 10 kHz, up to and
including 100 kHz; and
[cir] Very-high-frequency sources operate above 100 kHz but below
200 kHz.
Sound pressure level:
[cir] Greater than 160 decibels (dB) referenced to 1 micropascal
(re: 1 [micro]Pa), but less than 180 dB re: 1 [micro]Pa;
[cir] Equal to 180 dB re: 1 [micro]Pa and up to and including 200
dB re: 1 [micro]Pa; and
[cir] Greater than 200 dB re: 1 [micro]Pa.
Application for which the source would be used:
[cir] Sources with similar functions that have similar
characteristics, such as pulse length (duration of each pulse), beam
pattern, and duty cycle.
The bins used for classifying active sonars and transducers that
are quantitatively analyzed in the TMAA are shown in Table 1. While
general parameters or source characteristics are shown in the table,
actual source parameters are classified.
Table 1--Sonar and Other Transducers Quantitatively Analyzed in the TMAA
----------------------------------------------------------------------------------------------------------------
For annual training activities
-----------------------------------------------------------------------------------------------------------------
Source class category Bin Description Units Annual 7-Year total
----------------------------------------------------------------------------------------------------------------
Mid-Frequency (MF) Tactical MF1 Hull-mounted H 271 1,897
and non-tactical sources surface ship
that produce signals from 1 sonars (e.g.,
to 10 kHz. AN/SQS-53C and
AN/SQS-60).
MF3 Hull-mounted H 25 175
submarine
sonars (e.g.,
AN/BQQ-10).
MF4 Helicopter- H 27 189
deployed
dipping sonars
(e.g., AN/AQS-
22).
MF5 Active acoustic I 126 882
sonobuoys
(e.g., DICASS).
MF6 Active I 14 98
underwater
sound signal
devices (e.g.,
MK 84).
MF11 Hull-mounted H 42 294
surface ship
sonars with an
active duty
cycle greater
than 80%.
MF12 Towed array H 14 98
surface ship
sonars with an
active duty
cycle greater
than 80%.
High-Frequency (HF) Tactical HF1 Hull-mounted H 12 84
and non-tactical sources submarine
that produce signals greater sonars (e.g.,
than 10 kHz but less than AN/BQQ-10).
100 kHz.
Anti-Submarine Warfare (ASW) ASW1 MF systems H 14 98
Tactical sources used during operating
ASW training activities. above 200 dB.
ASW2 MF Multistatic H 42 294
Active
Coherent
sonobuoy
(e.g., AN/SSQ-
125).
ASW3 MF towed active H 273 1,911
acoustic
countermeasure
systems (e.g.,
AN/SLQ-25).
ASW4 MF expendable I 7 49
active
acoustic
device
countermeasure
s (e.g., MK3).
----------------------------------------------------------------------------------------------------------------
Notes: H = hours, I = count (e.g., number of individual pings or individual sonobuoys), DICASS = Directional
Command Activated Sonobuoy System.
Explosive Stressors
The near-instantaneous rise from ambient to an extremely high peak
pressure is what makes an explosive shock wave potentially damaging.
Farther from an explosive, the peak pressures decay and the explosive
waves propagate as an impulsive, broadband sound. Several parameters
influence the effect of an explosive: the weight of the explosive in
the warhead, the type of explosive material, the boundaries and
characteristics of the propagation medium, and the detonation depth in
water. The net explosive weight, which is the explosive power of a
charge expressed as the equivalent weight of trinitrotoluene (TNT),
accounts for the first two parameters. The effects of these factors are
explained in Appendix B (Acoustic and Explosive Concepts) of the 2020
GOA DSEIS/OEIS.
Explosive Use
Explosive detonations during training activities are from the use
of explosive bombs, and naval gun shells; however, no in-water
explosive detonations are included as part of the training activities.
For purposes of the analysis in this proposed rule, detonations
occurring in air at a height of 33 ft (10 m) or less above the water
surface, and detonations occurring directly on the water surface, were
modeled to detonate at a depth of 0.3 ft (0.1 m) below the water
surface since there is currently no other identified methodology for
modeling potential effects to marine
[[Page 49663]]
mammals that are underwater as a result of detonations occurring in-air
at or above the surface of the ocean (within 10 m above the surface).
This conservative approach over-estimates the potential underwater
impacts due to low-altitude and surface explosives by assuming that all
explosive energy is released and remains under the water surface.
Explosive stressors resulting from the detonation of some
munitions, such as missiles and gun rounds used in air-air and surface-
air scenarios, occur at high altitude. The resulting sound energy from
those detonations in air would not impact marine mammals. The explosive
energy released by detonations in air has been well studied, and basic
methods are available to estimate the explosive energy exposure with
distance from the detonation (e.g., U.S. Department of the Navy
(1975)). In air, the propagation of impulsive noise from an explosion
is highly influenced by atmospheric conditions, including temperature
and wind. While basic estimation methods do not consider the unique
environmental conditions that may be present on a given day, they do
allow for approximation of explosive energy propagation under neutral
atmospheric conditions. Explosions that occur during Air Warfare would
typically be at a sufficient altitude that a large portion of the sound
refracts upward due to cooling temperatures with increased altitude.
Based on an understanding of the explosive energy released by
detonations in air, detonations occurring in air at altitudes greater
than 10 m above the surface of the ocean are not likely to result in
acoustic impacts on marine mammals; therefore, these types of explosive
activities will not be discussed further in this document. (Note that
most of these in-air detonations would occur at altitudes substantially
greater than 10 m above the surface of the ocean, as described in
further detail in section 3.0.4.2.2 (Explosions in Air) of the 2020 GOA
DSEIS/OEIS.) Activities such as air-surface bombing or surface-surface
gunnery scenarios may involve the use of explosive munitions that
detonate upon impact with targets at or above the water surface (within
10 m above the surface). For these activities, acoustic effects
modeling was undertaken as described below.
In order to organize and facilitate the analysis of explosives,
explosive classification bins were developed. The use of explosive
classification bins provides the same benefits as described for
acoustic source classification bins in the Acoustic Stressors section,
above.
The explosive bin types and the number of explosives detonating at
or above the water surface in the TMAA are shown in Table 2.
Table 2--Explosive Sources Quantitatively Analyzed That Detonate At or Above the Water Surface in the TMAA
----------------------------------------------------------------------------------------------------------------
Number of explosives
Explosives (source class and net explosive weight (NEW)) Number of explosives with the specified
(lb.) * with the specified activity (7-year
activity (annually) total)
----------------------------------------------------------------------------------------------------------------
E5 (>5-10 lb. NEW)............................................ 56 392
E9 (>100-250 lb. NEW)......................................... 64 448
E10 (>250-500 lb. NEW)........................................ 6 42
E12 (>650-1,000 lb. NEW)...................................... 2 14
----------------------------------------------------------------------------------------------------------------
* All of the E5, E9, E10, and E12 explosives would occur in-air, at or above the surface of the water, and would
also occur offshore away from the continental shelf and slope beyond the 4,000-meter isobath.
Propagation of explosive pressure waves in water is highly
dependent on environmental characteristics such as bathymetry, bottom
type, water depth, temperature, and salinity, which affect how the
pressure waves are reflected, refracted, or scattered; the potential
for reverberation; and interference due to multi-path propagation. In
addition, absorption greatly affects the distance over which higher-
frequency components of explosive broadband noise can propagate.
Appendix B (Acoustic and Explosive Concepts) of the 2020 GOA DSEIS/OEIS
explains the characteristics of explosive detonations and how the above
factors affect the propagation of explosive energy in the water.
Because of the complexity of analyzing sound propagation in the ocean
environment, the Navy relies on acoustic models in its environmental
analyses that consider sound source characteristics and varying ocean
conditions across the TMAA.
For in-air explosives detonating at or above the water surface, the
model estimating acoustic impacts assumes that all acoustic energy from
the detonation is underwater with no loss of sound or energy into the
air. Important considerations must be factored into the analysis of
results with these modeling assumptions, given that the peak pressure
and sound from a detonation in air significantly decreases across the
air-water interface as it is partially reflected by the water's surface
and partially transmitted underwater, as detailed in the following
paragraphs.
Detonation of an explosive in air creates a supersonic high
pressure shock wave that expands outward from the point of detonation
(Kinney and Graham, 1985; Swisdak, 1975). The near-instantaneous rise
from ambient to an extremely high peak pressure is what makes the
explosive shock wave potentially injurious to an animal experiencing
the rapid pressure change (U.S. Department of the Navy, 2017a). As the
shock wave-front travels away from the point of detonation, it slows
and begins to behave as an acoustic wave-front travelling at the speed
of sound. Whereas a shock wave from a detonation in-air has an abrupt
peak pressure, that same pressure disturbance when transmitted through
the water surface results in an underwater pressure wave that begins
and ends more gradually compared with the in-air shock wave, and
diminishes with increasing depth and distance from the source (Bolghasi
et al., 2017; Chapman and Godin, 2004; Cheng and Edwards, 2003; Moody,
2006; Richardson et al., 1995; Sawyers, 1968; Sohn et al., 2000;
Swisdak, 1975; Waters and Glass, 1970; Woods et al., 2015). The
propagation of the shock wave in-air and then transitioning underwater
is very different from a detonation occurring deep underwater where
there is little interaction with the surface. In the case of an
underwater detonation occurring just below the surface, a portion of
the energy from the detonation would be released into the air (referred
to as surface blow off), and at greater depths a pulsating, air-filled
cavitation bubble would form, collapse, and reform around the
detonation point (Urick, 1983). The Navy's acoustic effects model for
analyzing underwater impacts on marine species does not account for the
loss of energy due to surface blow-
[[Page 49664]]
off or cavitation at depth. Both of these phenomena would diminish the
magnitude of the acoustic energy received by an animal under real-world
conditions (U.S. Department of the Navy, 2018b).
To more completely analyze the results predicted by the Navy's
acoustic effects model from detonations occurring in-air above the
ocean surface, it is necessary to consider the transfer of energy
across the air-water interface. Much of the scientific literature on
the transferal of shock wave impulse across the air-water interface has
focused on energy from sonic booms created by fast moving aircraft
flying at low altitudes above the ocean (Chapman and Godin, 2004; Cheng
and Edwards, 2003; Moody, 2006; Sawyers, 1968; Waters and Glass, 1970).
The shock wave created by a sonic boom is similar to the propagation of
a pressure wave generated by an explosion (although having a
significantly slower rise in peak pressure) and investigations of sonic
booms are somewhat informative. Waters and Glass (1970) were also
investigating sonic booms, but their methodology involved actual in-air
detonations. In those experiments, they detonated blasting caps
elevated 30 ft (9 m) above the surface in a flooded quarry and measured
the resulting pressure at and below the surface to determine the
penetration of the shock wave across the air-water interface.
Microphones above the water surface recorded the peak pressure in-air,
and hydrophones at various shallow depths underwater recorded the
unreflected remainder of the pressure wave after transition across the
air-water interface. The peak pressure measurements were compared and
the results supported the theoretical expectations for the penetration
of a pressure wave from air into water, including the predicted
exponential decay of energy with distance from the source underwater.
In effect, the air-water interface acted as a low-pass filter
eliminating the high-frequency components of the shock wave. At
incident angles greater than 14 degrees perpendicular to the surface,
most of the shock wave from the detonation was reflected off the water
surface, which is consistent with results from similar research (Cheng
and Edwards, 2003; Moody, 2006; Yagla and Stiegler, 2003). Given that
marine mammals spend, on average, up to 90 percent of their time
underwater (Costa, 1993; Costa and Block, 2009), and the shock wave
from a detonation is only a few milliseconds in duration, marine
mammals are unlikely to be exposed in-air when surfaced.
Vessel Strike
NMFS also considered the chance that a vessel utilized in training
activities could strike a marine mammal in the GOA Study Area,
including both the TMAA and WMA portions of the Study Area. Vessel
strikes have the potential to result in incidental take from serious
injury and/or mortality. Vessel strikes are not specific to any
particular training activity, but rather are a limited, sporadic, and
incidental result of Navy vessel movement within a study area. Vessel
strikes from commercial, recreational, and military vessels are known
to seriously injure and occasionally kill cetaceans (Abramson et al.,
2011; Berman-Kowalewski et al., 2010; Calambokidis, 2012; Douglas et
al., 2008; Laggner, 2009; Lammers et al., 2003; Van der Hoop et al.,
2012; Van der Hoop et al., 2013), although reviews of the literature on
ship strikes mainly involve collisions between commercial vessels and
whales (Jensen and Silber, 2003; Laist et al., 2001). Vessel speed,
size, and mass are all important factors in determining both the
potential likelihood and impacts of a vessel strike to marine mammals
(Conn and Silber, 2013; Gende et al., 2011; Silber et al., 2010;
Vanderlaan and Taggart, 2007; Wiley et al., 2016). For large vessels,
speed and angle of approach can influence the severity of a strike.
Navy vessels transit at speeds that are optimal for fuel
conservation and to meet training requirements. Vessels used as part of
the proposed specified activities include ships, submarines, unmanned
vessels, and boats ranging in size from small, 22 ft (7 m) rigid hull
inflatable boats to aircraft carriers with lengths up to 1,092 ft (333
m). The average speed of large Navy ships ranges between 10 and 15
knots (kn; 19-28 km/hr), and submarines generally operate at speeds in
the range of 8 to 13 kn (15 to 24 km/hr), while a few specialized
vessels can travel at faster speeds. Small craft (for purposes of this
analysis, less than 18 m in length) have much more variable speeds (0
to 50+ kn (0 to 93+ km/hr)), dependent on the activity), but generally
range from 10 to 14 kn (19-26 km/hr). From unpublished Navy data,
average median speed for large Navy ships in the other Navy ranges from
2011-2015 varied from 5 to 10 kn (9 to 19 km/hr) with variations by
ship class and location (i.e., slower speeds close to the coast).
Similar patterns would occur in the GOA Study Area. A full description
of Navy vessels that are used during training activities can be found
in Section 1.2.1 and Section 2.4.2.1 of the 2011 GOA FEIS/OEIS.
While these speeds are representative of most events, some vessels
need to temporarily operate outside of these parameters for certain
times or during certain activities. For example, to produce the
required relative wind speed over the flight deck, an aircraft carrier
engaged in flight operations must adjust its speed through the water
accordingly. Also, there are other instances, such as launch and
recovery of a small rigid hull inflatable boat; vessel boarding,
search, and seizure training events; or retrieval of a target when
vessels would be dead in the water or moving slowly ahead to maintain
steerage.
Large Navy vessels (greater than 18 m in length) within the
offshore areas of range complexes operate differently from commercial
vessels in ways that may reduce potential whale collisions. Surface
ships operated by or for the Navy have multiple personnel assigned to
stand watch at all times when a ship or surfaced submarine is moving
through the water (underway). A primary duty of personnel standing
watch on surface ships is to detect and report all objects and
disturbances sighted in the water that may indicate a threat to the
vessel and its crew, such as debris, a periscope, surfaced submarine,
or surface disturbance. Per vessel safety requirements, personnel
standing watch also report any marine mammals sighted in the path of
the vessel as a standard collision avoidance procedure. All vessels
proceed at a safe speed so they can take proper and effective action to
avoid a collision with any sighted object or disturbance, and can be
stopped within a distance appropriate to the prevailing circumstances
and conditions.
Detailed Description of Proposed Activities
Proposed Training Activities
The Navy proposes to conduct a single carrier strike group (CSG)
exercise which would last for a maximum of 21 consecutive days in a
year. The CSG exercise is comprised of several individual training
activities. Table 3 lists and describes those individual activities
that may result in takes of marine mammals. The events listed would
occur intermittently during the 21 days and could be simultaneous and
in the same general area within the TMAA or could be independent and
spatially separate from other ongoing activities. The table is
organized according to primary mission areas and includes the activity
name, associated stressor(s), description and duration of the activity,
sound source bin, the areas
[[Page 49665]]
where the activities are conducted in the GOA Study Area, the maximum
number of events per year in the 21-day period, and the maximum number
of events over 7 years. Not all sound sources are used with each
activity. The ``Annual # of Events'' column indicates the maximum
number of times that activity could occur during any single year. The
``7-Year # of Events'' is the maximum number of times an activity would
occur over the 7-year period of the proposed regulations if the
training occurred each year and at the maximum levels requested. The
events listed would occur intermittently during the exercise over a
maximum of 21 days. The maximum number of activities may not occur in
some years, and historically, training has occurred only every other
year. However, to conduct a conservative analysis, NMFS analyzed the
maximum times these activities could occur over one year and 7 years.
The 2020 GOA DSEIS/OEIS includes more detailed activity descriptions.
(Note the Navy proposes no low-frequency active sonar (LFAS) use for
the activities in this rulemaking.)
Table 3--Proposed Training Activities Analyzed for the 7-Year Period in the GOA Study Area
----------------------------------------------------------------------------------------------------------------
Annual # of 7-year # of
Stressor category Activity Description Source bin events events
----------------------------------------------------------------------------------------------------------------
Surface Warfare
----------------------------------------------------------------------------------------------------------------
Explosive.................... Gunnery Surface ship E5............. 6 42
Exercise, crews fire
Surface-to- inert small-
Surface (GUNEX- caliber, inert
S-S). medium-
caliber, or
large-caliber
explosive
rounds at
surface
targets.
Explosive.................... Bombing Fixed-wing E9, E10, E12... 18 126
Exercise (Air- aircraft
to-Surface) conduct
(BOMBEX [A-S]). bombing
exercises
against
stationary
floating
targets, towed
targets, or
maneuvering
targets.
----------------------------------------------------------------------------------------------------------------
Anti-Submarine Warfare (ASW)
----------------------------------------------------------------------------------------------------------------
Acoustic..................... Tracking Helicopter MF4, MF5, MF6.. 22 154
Exercise--Heli crews search
copter for, track,
(TRACKEX--Helo and detect
). submarines.
Acoustic..................... Tracking Maritime patrol MF5, MF6, ASW2. 13 91
Exercise--Mari aircraft crews
time Patrol search for,
Aircraft track, and
(TRACKEX--MPA). detect
submarines.
Acoustic..................... Tracking Surface ship ASW1, ASW3, 2 14
Exercise--Ship crews search MF1, MF11,
(TRACKEX--Ship for, track, MF12.
). and detect
submarines.
Acoustic..................... Tracking Submarine crews ASW4, HF1, MF3. 2 14
Exercise--Subm search for,
arine track, and
(TRACKEX--Sub). detect
submarines.
----------------------------------------------------------------------------------------------------------------
Notes: S-S = Surface to Surface, A-S = Air to Surface.
Standard Operating Procedures
For training to be effective, personnel must be able to safely use
their sensors and weapon systems as they are intended to be used in
military missions and combat operations and to their optimum
capabilities. Standard operating procedures applicable to training have
been developed through years of experience, and their primary purpose
is to provide for safety (including public health and safety) and
mission success. Because standard operating procedures are essential to
safety and mission success, the Navy considers them to be part of the
proposed specified activities, and has included them in the analysis.
In many cases, there are benefits to natural and cultural resources
resulting from standard operating procedures. Standard operating
procedures that are recognized as having a potential benefit to marine
mammals during training activities are noted below and discussed in
more detail within the 2020 GOA DSEIS/OEIS.
Vessel Safety;
Weapons Firing Procedures;
Target Deployment and Retrieval Safety; and
Towed In-Water Device Procedures.
Standard operating procedures (which are implemented regardless of
their secondary benefits) are different from mitigation measures (which
are designed entirely for the purpose of avoiding or reducing impacts).
Information on mitigation measures is provided in the Proposed
Mitigation Measures section below. Additional information on standard
operating procedures is presented in Section 2.3.2 (Standard Operating
Procedures) in the 2020 GOA DSEIS/OEIS.
Description of Marine Mammals and Their Habitat in the Area of the
Specified Activities
Marine mammal species and their associated stocks that have the
potential to occur in the GOA Study Area are presented in Table 4 along
with each stock's ESA and MMPA statuses, abundance estimate and
associated coefficient of variation value, minimum abundance estimate,
and expected occurrence in the GOA Study Area. The Navy requested
authorization to take individuals of 16 marine mammal species by Level
A harassment and Level B harassment, and NMFS has conservatively
analyzed and proposes to authorize incidental take of two additional
species. The Navy does not request authorization for any serious
injuries or mortalities of marine mammals, and NMFS agrees that serious
injury and mortality is unlikely to occur from the Navy's activities.
NMFS recently designated critical habitat under the Endangered Species
Act (ESA) for humpback whales in the TMAA portion of the GOA Study
Area, and this designated critical habitat is considered below (86 FR
21082; April 21, 2021). The WMA portion of the GOA Study Area does not
overlap ESA-designated critical habitat for humpback whales or any
other species.
Information on the status, distribution, abundance, population
trends, habitat, and ecology of marine mammals in the GOA Study Area
may be found in Chapter 4 of the Navy's rulemaking/LOA application.
NMFS has reviewed this information and found it
[[Page 49666]]
to be accurate and complete. Additional information on the general
biology and ecology of marine mammals is included in the 2020 GOA
DSEIS/OEIS. Table 4 incorporates the best available science, including
data from the 2020 U.S. Pacific and the Alaska Marine Mammal Stock
Assessment Reports (SARs; Carretta et al., 2021; Muto et al., 2021),
2021 draft U.S. Pacific and Alaska Marine Mammal SARs, as well as
monitoring data from the Navy's marine mammal research efforts.
To better define marine mammal occurrence in the TMAA, the portion
of the GOA Study Area where take of marine mammals is anticipated to
occur, four regions within the TMAA were defined (and are depicted in
Figure 3-1 of the Navy's rulemaking/LOA application), consistent with
the survey strata used by Rone et al. (2017) during the most recent
marine mammal surveys in the TMAA. The four regions are: inshore,
slope, seamount, and offshore.
Species Not Included in the Analysis
There has been no change in the species unlikely to be present in
the GOA Study Area since the last MMPA rulemaking process (82 FR 19530;
April 27, 2017). The species carried forward for analysis are those
likely to be found in the GOA Study Area based on the most recent data
available and do not include species that may have once inhabited or
transited the area but have not been sighted in recent years (e.g.,
species which were extirpated from factors such as 19th and 20th
century commercial exploitation). Several species and stocks that may
be present in the northeast Pacific Ocean generally have an extremely
low probability of presence in the GOA Study Area. These species and
stocks are considered extralimital (may be sightings, acoustic
detections, or stranding records, but the GOA Study Area is outside the
species' range of normal occurrence) or rare (occur in the GOA Study
Area sporadically, but sightings are rare). These species and stocks
include the Eastern North Pacific Northern Resident and the West Coast
Transient stocks of killer whale (Orcinus orca), beluga whale
(Delphinapterus leucas), false killer whale (Pseudorca crassidens),
short-finned pilot whale (Globicephala macrorhynchus), northern right
whale dolphin (Lissodelphis borealis), and Risso's dolphin (Grampus
griseus).
The Eastern North Pacific Northern Resident and the West Coast
Transient stocks of killer whale are considered extralimital in the GOA
Study Area. Given the paucity of any beluga whale sightings in the GOA
(Laidre et al. 2000), the occurrence of this species within the GOA
Study Area is considered extralimital. The GOA Study Area is also
outside of the normal range of the false killer whale's distribution in
the Pacific Ocean, and despite rare stranding or sighting reports, the
GOA Study Area is outside of the normal range of the short-finned pilot
whale as well. There are two sighting records of northern right whale
dolphins in the Gulf of Alaska, but these are considered extremely rare
(U.S. Department of the Navy 2006; NOAA 2012) and extralimital in the
GOA Study Area. There are a few records of Risso's dolphins near the
GOA Study Area; however, their occurrence within the GOA Study Area is
rare, and therefore Risso's dolphin is considered extralimital. NMFS
agrees with the Navy's assessment that these species are unlikely to
occur in the GOA Study Area and they are not discussed further.
One species of marine mammal, the Northern sea otter, occurs in the
Gulf of Alaska but is managed by the U.S. Fish and Wildlife Service and
is not considered further in this document.
Table 4--Marine Mammal Occurrence Within the GOA Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stock abundance
ESA status, (CV, Nmin, year of
Common name Scientific name Stock MMPA status, most recent PBR Annual M/ Occurrence in GOA
strategic (Y/ abundance survey) SI \3\ study area \4\
N) \1\ \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetacea--Suborder Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae (right
whales):
North Pacific right whale... Eubalaena japonica. Eastern North E, D, Y 31 (0.226, 26, \5\ 0.05 0 Rare.
Pacific. 2008).
Family Balaenopteridae
(rorquals):
Humpback whale.............. Megaptera Central North -, -, Y 10,103 (0.3, 83 26 Seasonal; highest
novaeangliae. Pacific \6\. 7,891, 2006). likelihood June
to September.
California, Oregon, -, -, Y 4,973 (0.05, 28.7 >=48.6 Seasonal; highest
and Washington \6\. 4,776, 2018). likelihood June
to September.
Western North E, D, Y 1,107 (0.3, 865, 3 2.8 Seasonal; highest
Pacific. 2006). likelihood June
to September.
Blue whale.................. Balaenoptera Eastern North E, D, Y 1,898 (0.085, 4.1 >=19.4 Seasonal; highest
musculus. Pacific. 1,767, 2018). likelihood June
to December.
Central North E, D, Y 133 (1.09, 63, 0.1 0 Seasonal; highest
Pacific. 2010). likelihood June
to December.
Fin whale................... Balaenoptera Northeast Pacific.. E, D, Y 3,168 (0.26, 5.1 0.6 Likely.
physalus. 2,554, 2013) \7\.
Sei whale................... Balaenoptera Eastern North E, D, Y 519 (0.4, 374, 0.75 >=0.2 Rare.
borealis. Pacific \8\. 2014).
Minke whale................. Balaenoptera Alaska............. -, -, N UNK............... UND 0 Likely.
acutorostrata.
Family Eschrichtiidae (gray
whale):
Gray whale.................. Eschrichtius Eastern North -, -, N 26,960 (0.05, 801 131 Likely: Highest
robustus. Pacific. 25,849, 2016). numbers during
seasonal
migrations (fall,
winter, spring).
[[Page 49667]]
Western North E, D, Y 290 (N/A, 271, 0.12 UNK Rare: Individuals
Pacific. 2016). migrate through
GOA.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetacea--Suborder Odontoceti (toothed whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae (sperm
whale):
Sperm whale................. Physeter North Pacific...... E, D, Y 345 (0.43, 244, UND 3.5 Likely; More
macrocephalus. 2015) \9\. likely in waters
>1,000 m depth,
most often >2,000
m.
Family Delphinidae (dolphins):
Killer whale................ Orcinus orca....... Eastern North -, -, N \10\ 2,347 (N/A, 24 1 Likely.
Pacific Alaska 2,347, 2012).
Resident.
Eastern North -, -, N 300 (0.1, 276, 2.8 0 Likely.
Pacific Offshore. 2012).
AT1 Transient...... -, D, Y \10\ 7 (N/A, 7, 0.01 0 Rare; more likely
2018). inside Prince
William Sound and
Kenai Fjords.
Eastern North -, -, N \10\ 587 (N/A, 5.87 0.8 Likely.
Pacific GOA, 587, 2012).
Aleutian Island,
and Bering Sea
Transient.
Pacific white-sided dolphin. Lagenorhynchus North Pacific...... -, -, N 26,880 (N/A, N/A, UND 0 Likely.
obliquidens. 1990).
Family Phocoenidae (porpoises):
Harbor porpoise............. Phocoena phocoena.. GOA................ -, -, Y 31,046 (0.21, N/A, UND 72 Rare; Inshore and
1998). Slope Regions, if
present.
Southeast Alaska... -, -, Y 1,354 (0.12, 12 34 Rare.
1,224, 2012).
Dall's porpoise............. Phocoenoides dalli. Alaska............. -, -, N 83,400 (0.097, UND 37 Likely.
3,110, 2015).
Family Ziphiidae (beaked
whales):
Cuvier's beaked whale....... Ziphius cavirostris Alaska............. -, -, N UNK............... UND 0 Likely.
Baird's beaked whale........ Berardius bairdii.. Alaska............. -, -, N UNK............... UND 0 Likely.
Stejneger's beaked whale.... Mesoplodon Alaska............. -, -, N UNK............... UND 0 Likely.
stejnegeri.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Suborder Pinnipedia \8\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otarieidae (fur seals and
sea lions):
Steller sea lion............ Eumetopias jubatus. Eastern U.S........ -, -, N \11\ 43,201 (N/A, 2,592 112 Rare.
43,201, 2017).
Western U.S........ E, D, Y \11\ 52,932 (N/A, 318 254 Likely; Inshore
52,932, 2013). region.
California sea lion......... Zalophus U.S................ -, -, N 257,606 (N/A, 14,011 >320 Rare (highest
californianus. 233,515, 2014). likelihood April
and May).
Northern fur seal........... Callorhinus ursinus Eastern Pacific.... -, D, Y 626,618 (0.2, 11,403 373 Likely.
530,376, 2019).
California......... -, D, N 14,050 (N/A, 451 1.8 Rare.
7,524, 2013).
Family Phocidae (true seals):
Northern elephant seal...... Mirounga California Breeding -, -, N 187,386 (N/A, 5,122 5.3 Seasonal (highest
angustirostris. 85,369, 2013). likelihood July-
September).
Harbor seal................. Phoca vitulina..... N Kodiak........... -, -, N 8,677 (N/A, 7,609, 228 38 Likely; Inshore
2017). region.
S Kodiak........... -, -, N 26,448 (N/A, 939 127 Likely; Inshore
22,351, 2017). region.
Prince William -, -, N 44,756 (N/A, 1,253 413 Likely; Inshore
Sound. 41,776, 2015). region.
Cook Inlet/Shelikof -, -, N 28,411 (N/A, 807 107 Likely; Inshore
26,907, 2018). region.
Ribbon seal................. Histriophoca Unidentified....... -, -, N 184,697 (N/A, 9,785 163 Rare.
fasciata. 163,086, 2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: CV = coefficient of variation, ESA = Endangered Species Act, GOA = Gulf of Alaska, m = meter(s), MMPA = Marine Mammal Protection Act, N/A = not
available, U.S. = United States, M/SI = mortality and serious injury, UNK = unknown, UND = undetermined.
[[Page 49668]]
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds potential biological removal (PBR) or which is determined to be declining and likely to be listed under the ESA within the foreseeable future.
Any species or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ The stocks and stock abundance number are as provided in Carretta et al., 2021 and Muto et al., 2021. Nmin is the minimum estimate of stock
abundance. In some cases, CV is not applicable. NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region.
\3\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality and serious injury (M/SI) from all sources combined (e.g.,
commercial fisheries, ship strike). Annual mortality and serious injury (M/SI) often cannot be determined precisely and is in some cases presented as
a minimum value or range. A CV associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ RARE: The distribution of the species is near enough to the GOA Study Area that the species could occur there, or there are a few confirmed
sightings. LIKELY: Year-round sightings or acoustic detections of the species in the GOA Study Area, although there may be variation in local
abundance over the year. SEASONAL: Species absence and presence as documented by surveys or acoustic monitoring. Regions within the GOA Study Area
follow those presented in Rone et al. (2015); Rone et al. (2009); Rone et al. (2014); Rone et al. (2017): inshore, slope, seamount, and offshore.
\5\ See SAR for more details
\6\ Humpback whales in the Central North Pacific stock and the California, Oregon, and Washington stock are from three Distinct Population Segments
based on animals identified in breeding areas in Hawaii, Mexico, and Central America (Carretta et al., 2021; Muto et al., 2021; National Marine
Fisheries Service, 2016c).
\7\ The SAR reports this stock abundance assessment as provisional and notes that it is an underestimate for the entire stock because it is based on
surveys which covered only a small portion of the stock's range.
\8\ This analysis assumes that these individuals are from the Eastern North Pacific stock; however, they are not discussed in the West Coast or the
Alaska Stock Assessment Reports (Carretta et al., 2021; Muto et al., 2021).
\9\ The SAR reports that this is an underestimate for the entire stock because it is based on surveys of a small portion of the stock's extensive range
and it does not account for animals missed on the trackline or for females and juveniles in tropical and subtropical waters.
\10\ Stock abundance is based on counts of individual animals identified from photo-identification catalogues. Surveys for abundance estimates of these
stocks are conducted infrequently.
\11\ Stock abundance is the best estimate of pup and non-pup counts, which have not been corrected to account for animals at sea during abundance
surveys.
Below, we consider additional information about the marine mammals
in the area of the specified activities that informs our analysis, such
as identifying known areas of important habitat or behaviors, or where
Unusual Mortality Events (UME) have been designated.
Critical Habitat
On April 21, 2021 (86 FR 21082), NMFS published a final rule
designating critical habitat for the endangered Western North Pacific
DPS, the endangered Central America DPS, and the threatened Mexico DPS
of humpback whales, including specific marine areas located off the
coasts of California, Oregon, Washington, and Alaska. Based on
consideration of national security, economic impacts, and data
deficiency in some areas, NMFS excluded certain areas from the
designation for each DPS.
NMFS identified prey species, primarily euphausiids and small
pelagic schooling fishes (see the final rule for particular prey
species identified for each DPS; 86 FR 21082; April 21, 2021) of
sufficient quality, abundance, and accessibility within humpback whale
feeding areas to support feeding and population growth, as an essential
habitat feature. NMFS, through a critical habitat review team (CHRT),
also considered inclusion of migratory corridors and passage features,
as well as sound and the soundscape, as essential habitat features.
However, NMFS did not include either, as the CHRT concluded that the
best available science did not allow for identification of any
consistently used migratory corridors or definition of any physical,
essential migratory or passage conditions for whales transiting between
or within habitats of the three DPSs. The best available science also
currently does not enable NMFS to identify a sound-related habitat
feature that is essential to the conservation of humpback whales.
NMFS considered the co-occurrence of this designated humpback whale
critical habitat and the GOA Study Area. Figure 4-1 of the Navy's
rulemaking/LOA application shows the overlap of the humpback whale
critical habitat with the TMAA. As shown in the Navy's rulemaking/LOA
application, the TMAA overlaps with humpback whale critical habitat
Unit 5 (destination for whales from the Hawaii, Mexico, and Western
North Pacific DPSs; Calambokidis et al., 2008) and Unit 8 (destination
for whales from the Hawaii and Mexico DPSs (Baker et al., 1986,
Calambokidis et al., 2008); Western North Pacific DPS whales have not
been photo-identified in this specific area, but presence has been
inferred based on available data indicating that humpback whales from
Western North Pacific wintering areas occur in the Gulf of Alaska (NMFS
2020, Table C5)). Approximately 4 percent of the humpback whale
critical habitat in the GOA region overlaps with the TMAA, and
approximately 2 percent of critical habitat in both the GOA and U.S.
west coast regions combined overlaps with the TMAA. The WMA portion of
the GOA Study Area does not overlap ESA-designated critical habitat for
humpback whales.
As noted above in the Geographical Region section, the TMAA
boundary was intentionally designed to avoid ESA-designated Western DPS
(MMPA Western U.S. stock) Steller sea lion critical habitat.
Biologically Important Areas
BIAs include areas of known importance for reproduction, feeding,
or migration, or areas where small and resident populations are known
to occur (Van Parijs, 2015). Unlike ESA critical habitat, these areas
are not formally designated pursuant to any statute or law, but are a
compilation of the best available science intended to inform impact and
mitigation analyses. An interactive map of BIAs may be found here:
https://cetsound.noaa.gov/biologically-important-area-map.
The WMA does not overlap with any known BIAs. BIAs in the GOA that
overlap portions of the TMAA include the following feeding and
migration areas: North Pacific right whale feeding BIA (June-
September); Gray whale migratory corridor BIA (November-January,
southbound; March-May, northbound) (Ferguson et al., 2015). Fin whale
feeding areas (east, west, and southwest of Kodiak Island) occur to the
west of the TMAA and gray whale feeding areas occur both east
(Southeast Alaska) and west (Kodiak Island) of the TMAA; however, these
feeding areas are located well outside of (> 20 nmi (37 km)) the TMAA
and beyond the Navy's estimated range to effects for take by Level A
harassment and Level B harassment.
A portion of the North Pacific right whale feeding BIA overlaps
with the western side of the TMAA by approximately 2,051 square
kilometers (km\2\; approximately 1.4 percent of the TMAA, and 7 percent
of the feeding BIA). A small portion of the gray whale migration
corridor BIA also overlaps with the western side of the TMAA by
approximately 1,582 km\2\ (approximately 1 percent of the TMAA, and 1
percent of the migration corridor BIA). To mitigate impacts to marine
mammals in these BIAs, the Navy would implement several procedural
mitigation measures and mitigation areas (described in the Proposed
Mitigation Measures section).
[[Page 49669]]
Unusual Mortality Events (UMEs)
A UME is defined under Section 410(6) of the MMPA as a stranding
that is unexpected; involves a significant die-off of any marine mammal
population; and demands immediate response. There is one UME that is
applicable to our evaluation of the Navy's activities in the GOA Study
Area. The gray whale UME along the west coast of North America is
active and involves ongoing investigations in the GOA that inform our
analysis are discussed below.
Gray Whale UME
Since January 1, 2019, elevated gray whale strandings have occurred
along the west coast of North America, from Mexico to Canada. As of
June 3, 2022, there have been a total of 578 strandings along the
coasts of the United States, Canada, and Mexico, with 278 of those
strandings occurring along the U.S. coast. Of the strandings on the
U.S. coast, 118 have occurred in Alaska, 66 in Washington, 14 in
Oregon, and 80 in California. Full or partial necropsy examinations
were conducted on a subset of the whales. Preliminary findings in
several of the whales have shown evidence of emaciation. These findings
are not consistent across all of the whales examined, so more research
is needed. As part of the UME investigation process, NOAA has assembled
an independent team of scientists to coordinate with the Working Group
on Marine Mammal Unusual Mortality Events to review the data collected,
sample stranded whales, consider possible causal-linkages between the
mortality event and recent ocean and ecosystem perturbations, and
determine the next steps for the investigation. Please refer to:
https://www.fisheries.noaa.gov/national/marine-life-distress/2019-2022-gray-whale-unusual-mortality-event-along-west-coast-and for more
information on this UME.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65 dB
threshold from the normalized composite audiograms, with the exception
for lower limits for low-frequency cetaceans where the lower bound was
deemed to be biologically implausible and the lower bound from Southall
et al. (2007) retained. The functional groups and the associated
frequencies are indicated below (note that these frequency ranges
correspond to the range for the composite group, with the entire range
not necessarily reflecting the capabilities of every species within
that group):
Low-frequency cetaceans (mysticetes): generalized hearing
is estimated to occur between approximately 7 Hz and 35 kHz;
Mid-frequency cetaceans (larger toothed whales, beaked
whales, and most delphinids): generalized hearing is estimated to occur
between approximately 150 Hz and 160 kHz;
High-frequency cetaceans (porpoises, river dolphins, and
members of the genera Kogia and Cephalorhynchus; including two members
of the genus Lagenorhynchus, on the basis of recent echolocation data
and genetic data): generalized hearing is estimated to occur between
approximately 275 Hz and 160 kHz;
Pinnipeds in water; Phocidae (true seals): generalized
hearing is estimated to occur between approximately 50 Hz to 86 kHz;
and
Pinnipeds in water; Otariidae (eared seals): generalized
hearing is estimated to occur between 60 Hz and 39 kHz.
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more details concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of the available
information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a discussion of the ways that components of
the specified activity may impact marine mammals and their habitat. The
Estimated Take of Marine Mammals section later in this rule includes a
quantitative analysis of the number of instances of take that could
occur from these activities. The Preliminary Analysis and Negligible
Impact Determination section considers the content of this section, the
Estimated Take of Marine Mammals section, and the Proposed Mitigation
Measures section to draw conclusions regarding the likely impacts of
these activities on the reproductive success or survivorship of
individuals and whether those impacts on individuals are likely to
adversely affect the species through effects on annual rates of
recruitment or survival.
The Navy has requested authorization for the take of marine mammals
that may occur incidental to training activities in the GOA Study Area.
The Navy analyzed potential impacts to marine mammals in its
rulemaking/LOA application. NMFS carefully reviewed the information
provided by the Navy along with independently reviewing applicable
scientific research and literature and other information to evaluate
the potential effects of the Navy's activities on marine mammals, which
are presented in this section. (As noted above, activities that would
result in take of marine mammals would only occur in the TMAA portion
of the GOA Study Area.)
Other potential impacts to marine mammals from training activities
in the GOA Study Area were analyzed in the Navy's rulemaking/LOA
application as well as in the 2020 GOA DSEIS/OEIS and 2022 Supplement
to the 2020 GOA DSEIS/OEIS, in consultation with NMFS as a cooperating
agency, and determined to be unlikely to result in marine mammal take.
These include incidental take from vessel strike and serious injury or
mortality from explosives. Therefore, the Navy did not request
authorization for incidental take of marine mammals by vessel strike or
serious injury or mortality from explosives from its proposed specified
activities. NMFS has carefully considered the information in the 2020
GOA DSEIS/OEIS, the 2022 Supplement to the 2020 GOA DSEIS/OEIS, and all
other pertinent information and agrees that incidental take is unlikely
to occur from these sources. NMFS conducted a detailed analysis of the
potential for vessel strike, and based on that analysis,
[[Page 49670]]
NMFS does not anticipate vessel strikes of large whales or smaller
marine mammals in the GOA Study Area. In this proposed rule, NMFS
analyzes the potential effects of the Navy's activities on marine
mammals in the GOA Study Area, focusing primarily on the activity
components that may cause the take of marine mammals: exposure to
acoustic or explosive stressors including non-impulsive (sonar and
other transducers) and impulsive (explosives) stressors.
For the purpose of MMPA incidental take authorizations, NMFS'
effects assessments serve four primary purposes: (1) to determine
whether the specified activities would have a negligible impact on the
affected species or stocks of marine mammals (based on whether it is
likely that the activities would adversely affect the species or stocks
through effects on annual rates of recruitment or survival); (2) to
determine whether the specified activities would have an unmitigable
adverse impact on the availability of the species or stocks for
subsistence uses; (3) to prescribe the permissible methods of taking
(i.e., Level B harassment (behavioral disturbance and temporary
threshold shift (TTS)), Level A harassment (permanent threshold shift
(PTS) and non-auditory injury), serious injury, or mortality),
including identification of the number and types of take that could
occur by harassment, serious injury, or mortality, and to prescribe
means of effecting the least practicable adverse impact on the species
or stocks and their habitat (i.e., mitigation measures); and (4) to
prescribe requirements pertaining to monitoring and reporting.
In this section, NMFS provides a description of the ways marine
mammals potentially could be affected by these activities in the form
of mortality, physical trauma, sensory impairment (permanent and
temporary threshold shifts and acoustic masking), physiological
responses (particularly stress responses), behavioral disturbance, or
habitat effects. The Estimated Take of Marine Mammals section discusses
how the potential effects on marine mammals from non-impulsive and
impulsive sources relate to the MMPA definitions of Level A Harassment
and Level B Harassment, and quantifies those effects that rise to the
level of a take. The Preliminary Analysis and Negligible Impact
Determination section assesses whether the proposed authorized take
would have a negligible impact on the affected species and stocks.
Potential Effects of Underwater Sound
Anthropogenic sounds cover a broad range of frequencies and sound
levels and can have a range of highly variable impacts on marine life,
from none or minor to potentially severe responses, depending on
received levels, duration of exposure, behavioral context, and various
other factors. The potential effects of underwater sound from active
acoustic sources can possibly result in one or more of the following:
temporary or permanent hearing impairment, non-auditory physical or
physiological effects, behavioral response, stress, and masking
(Richardson et al., 1995; Gordon et al., 2004; Nowacek et al., 2007;
Southall et al., 2007; G[ouml]tz et al., 2009, Southall et al., 2019a).
The degree of effect is intrinsically related to the signal
characteristics, received level, distance from the source, and duration
of the sound exposure. In general, sudden, high level sounds can cause
hearing loss, as can longer exposures to lower level sounds. Temporary
or permanent loss of hearing can occur after exposure to noise, and
occurs almost exclusively for noise within an animal's hearing range.
Note that in the following discussion, we refer in many cases to a
review article concerning studies of noise-induced hearing loss
conducted from 1996-2015 (i.e., Finneran, 2015). For study-specific
citations, please see that work. We first describe general
manifestations of acoustic effects before providing discussion specific
to the Navy's activities.
Richardson et al. (1995) described zones of increasing intensity of
effect that might be expected to occur, in relation to distance from a
source and assuming that the signal is within an animal's hearing
range. First is the area within which the acoustic signal would be
audible (potentially perceived) to the animal, but not strong enough to
elicit any overt behavioral or physiological response. The next zone
corresponds with the area where the signal is audible to the animal and
of sufficient intensity to elicit behavioral or physiological
responsiveness. Third is a zone within which, for signals of high
intensity, the received level is sufficient to potentially cause
discomfort or tissue damage to auditory systems. Overlaying these zones
to a certain extent is the area within which masking (i.e., when a
sound interferes with or masks the ability of an animal to detect a
signal of interest that is above the absolute hearing threshold) may
occur; the masking zone may be highly variable in size.
We also describe more severe potential effects (i.e., certain non-
auditory physical or physiological effects). Potential effects from
impulsive sound sources can range in severity from effects such as
behavioral disturbance or tactile perception to physical discomfort,
slight injury of the internal organs and the auditory system, or
mortality (Yelverton et al., 1973). Non-auditory physiological effects
or injuries that theoretically might occur in marine mammals exposed to
high level underwater sound or as a secondary effect of extreme
behavioral reactions (e.g., change in dive profile as a result of an
avoidance reaction) include neurological effects, bubble formation,
resonance effects, and other types of organ or tissue damage (Cox et
al., 2006; Southall et al., 2007; Zimmer and Tyack, 2007; Tal et al.,
2015).
Acoustic Sources
Direct Physiological Effects
Non-impulsive sources of sound can cause direct physiological
effects including noise-induced loss of hearing sensitivity (or
``threshold shift''), nitrogen decompression, acoustically-induced
bubble growth, and injury due to sound-induced acoustic resonance. Only
noise-induced hearing loss is anticipated to occur due to the Navy's
activities. Acoustically-induced (or mediated) bubble growth and other
pressure-related physiological impacts are addressed below, but are not
expected to result from the Navy's activities. Separately, an animal's
behavioral reaction to an acoustic exposure might lead to physiological
effects that might ultimately lead to injury or death, which is
discussed later in the Stranding and Mortality subsection.
Hearing Loss--Threshold Shift
Marine mammals exposed to high-intensity sound, or to lower-
intensity sound for prolonged periods, can experience hearing threshold
shift, which is the loss of hearing sensitivity at certain frequency
ranges after cessation of sound (Finneran, 2015). Threshold shift can
be permanent (PTS), in which case the loss of hearing sensitivity is
not fully recoverable, or temporary (TTS), in which case the animal's
hearing threshold would recover over time (Southall et al., 2007). TTS
can last from minutes or hours to days (i.e., there is recovery back to
baseline/pre-exposure levels), can occur within a specific frequency
range (i.e., an animal might only have a temporary loss of hearing
sensitivity within a limited frequency band of its auditory
[[Page 49671]]
range), and can be of varying amounts (e.g., an animal's hearing
sensitivity might be reduced by only 6 dB or reduced by 30 dB). While
there is no simple functional relationship between TTS and PTS or other
auditory injury (e.g., neural degeneration), as TTS increases, the
likelihood that additional exposure sound pressure level (SPL) or
duration will result in PTS or other injury also increases (see also
the 2020 GOA DSEIS/OEIS for additional discussion). Exposure thresholds
for the onset of PTS or other auditory injury are defined by the amount
of sound energy that results in 40 dB of TTS. This value is informed by
experimental data, and is used as a proxy for the onset of auditory
injury; i.e., it is assumed that exposures beyond those capable of
causing 40 dB of TTS have the potential to result in PTS or other
auditory injury (e.g., loss of cochlear neuron synapses, even in the
absence of PTS). In severe cases of PTS, there can be total or partial
deafness, while in most cases the animal has an impaired ability to
hear sounds in specific frequency ranges (Kryter, 1985).
When PTS occurs, there is physical damage to the sound receptors in
the ear (i.e., tissue damage), whereas TTS represents primarily tissue
fatigue and is reversible (Southall et al., 2007). PTS is permanent
(i.e., there is incomplete recovery back to baseline/pre-exposure
levels), but also can occur in a specific frequency range and amount as
mentioned above for TTS. In addition, other investigators have
suggested that TTS is within the normal bounds of physiological
variability and tolerance and does not represent physical injury (e.g.,
Ward, 1997). Therefore, NMFS does not consider TTS to constitute
auditory injury.
The following physiological mechanisms are thought to play a role
in inducing auditory threshold shift: effects to sensory hair cells in
the inner ear that reduce their sensitivity; modification of the
chemical environment within the sensory cells; residual muscular
activity in the middle ear; displacement of certain inner ear
membranes; increased blood flow; and post-stimulatory reduction in both
efferent and sensory neural output (Southall et al., 2007). The
amplitude, duration, frequency, temporal pattern, and energy
distribution of sound exposure all can affect the amount of associated
threshold shift and the frequency range in which it occurs. Generally,
the amount of threshold shift, and the time needed to recover from the
effect, increase as amplitude and duration of sound exposure increases.
Human non-impulsive noise exposure guidelines are based on the
assumption that exposures of equal energy (the same sound exposure
level (SEL)) produce equal amounts of hearing impairment regardless of
how the sound energy is distributed in time (NIOSH, 1998). Previous
marine mammal TTS studies have also generally supported this equal
energy relationship (Southall et al., 2007). However, some more recent
studies concluded that for all noise exposure situations the equal
energy relationship may not be the best indicator to predict TTS onset
levels (Mooney et al., 2009a and 2009b; Kastak et al., 2007). These
studies highlight the inherent complexity of predicting TTS onset in
marine mammals, as well as the importance of considering exposure
duration when assessing potential impacts. Generally, with sound
exposures of equal energy, those that were quieter (lower SPL) with
longer duration were found to induce TTS onset at lower levels than
those of louder (higher SPL) and shorter duration. Less threshold shift
will occur from intermittent sounds than from a continuous exposure
with the same energy (some recovery can occur between intermittent
exposures) (Kryter et al., 1966; Ward, 1997; Mooney et al., 2009a,
2009b; Finneran et al., 2010). For example, one short but loud (higher
SPL) sound exposure may induce the same impairment as one longer but
softer (lower SPL) sound, which in turn may cause more impairment than
a series of several intermittent softer sounds with the same total
energy (Ward, 1997). Additionally, though TTS is temporary, very
prolonged or repeated exposure to sound strong enough to elicit TTS, or
shorter-term exposure to sound levels well above the TTS threshold can
cause PTS, at least in terrestrial mammals (Kryter, 1985; Lonsbury-
Martin et al., 1987).
PTS is considered auditory injury (Southall et al., 2007).
Irreparable damage to the inner or outer cochlear hair cells may cause
PTS; however, other mechanisms are also involved, such as exceeding the
elastic limits of certain tissues and membranes in the middle and inner
ears and resultant changes in the chemical composition of the inner ear
fluids (Southall et al., 2007).
The NMFS Acoustic Technical Guidance (NMFS, 2018), which was used
in the assessment of effects for this rule, compiled, interpreted, and
synthesized the best available scientific information for noise-induced
hearing effects for marine mammals to derive updated thresholds for
assessing the impacts of noise on marine mammal hearing. More recently,
Southall et al. (2019a) evaluated Southall et al. (2007) and used
updated scientific information to propose revised noise exposure
criteria to predict onset of auditory effects in marine mammals (i.e.,
PTS and TTS onset). Southall et al. (2019a) note that the quantitative
processes described and the resulting exposure criteria (i.e.,
thresholds and auditory weighting functions) are largely identical to
those in Finneran (2016) and NMFS (2018). They only differ in that the
Southall et al. (2019a) exposure criteria are more broadly applicable
as they include all marine mammal species (rather than only those under
NMFS jurisdiction) for all noise exposures (both in air and underwater
for amphibious species) and, while the hearing group compositions are
identical, they renamed the hearing groups. Southall et al. (2021)
updated the behavioral response severity criteria laid out in Southall
et al. (2007) and included recommendations on how to present and score
behavioral responses in future work.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran (2015) and Southall et al. (2019a) for
summaries), however for cetaceans, published data on the onset of TTS
are limited to the captive bottlenose dolphin, beluga, harbor porpoise,
and Yangtze finless porpoise, and for pinnipeds in water, measurements
of TTS are limited to harbor seals, elephant seals, and California sea
lions. These studies examine hearing thresholds measured in marine
mammals before and after exposure to intense sounds. The difference
between the pre-exposure and post-exposure thresholds can then be used
to determine the amount of threshold shift at various post-exposure
times. NMFS has reviewed the available studies, which are summarized
below (see also the 2020 GOA DSEIS/OEIS which includes additional
discussion on TTS studies related to sonar and other transducers).
The method used to test hearing may affect the resulting
amount of measured TTS, with neurophysiological measures producing
larger amounts of TTS compared to psychophysical measures (Finneran et
al., 2007; Finneran, 2015).
The amount of TTS varies with the hearing test frequency.
As the exposure SPL increases, the frequency at which the maximum TTS
occurs also increases (Kastelein et al., 2014b). For high-level
exposures, the maximum TTS typically occurs one-half to one octave
above the exposure frequency (Finneran et al., 2007; Mooney et al.,
2009a; Nachtigall et al., 2004; Popov et al., 2011; Popov et al., 2013;
Schlundt et al., 2000;
[[Page 49672]]
Kastelein et al., 2021b; Kastelien et al., 2022). The overall spread of
TTS from tonal exposures can therefore extend over a large frequency
range (i.e., narrowband exposures can produce broadband (greater than
one octave) TTS).
The amount of TTS increases with exposure SPL and duration
and is correlated with SEL, especially if the range of exposure
durations is relatively small (Kastak et al., 2007; Kastelein et al.,
2014b; Popov et al., 2014). As the exposure duration increases,
however, the relationship between TTS and SEL begins to break down.
Specifically, duration has a more significant effect on TTS than would
be predicted on the basis of SEL alone (Finneran et al., 2010a; Kastak
et al., 2005; Mooney et al., 2009a). This means if two exposures have
the same SEL but different durations, the exposure with the longer
duration (thus lower SPL) will tend to produce more TTS than the
exposure with the higher SPL and shorter duration. In most acoustic
impact assessments, the scenarios of interest involve shorter duration
exposures than the marine mammal experimental data from which impact
thresholds are derived; therefore, use of SEL tends to over-estimate
the amount of TTS. Despite this, SEL continues to be used in many
situations because it is relatively simple, more accurate than SPL
alone, and lends itself easily to scenarios involving multiple
exposures with different SPL.
Gradual increases of TTS may not be directly observable
with increasing exposure levels, before the onset of PTS (Reichmuth et
al., 2019). Similarly, PTS can occur without measurable behavioral
modifications (Reichmuth et al., 2019).
The amount of TTS depends on the exposure frequency.
Sounds at low frequencies, well below the region of best sensitivity,
are less hazardous than those at higher frequencies, near the region of
best sensitivity (Finneran and Schlundt, 2013). The onset of TTS--
defined as the exposure level necessary to produce 6 dB of TTS (i.e.,
clearly above the typical variation in threshold measurements)--also
varies with exposure frequency. At low frequencies, onset-TTS exposure
levels are higher compared to those in the region of best sensitivity.
For example, for harbor porpoises exposed to one-sixth octave noise
bands at 16 kHz (Kastelein et al., 2019f), 32 kHz (Kastelein et al.,
2019d), 63 kHz (Kastelein et al., 2020a), and 88.4 kHz (Kastelein et
al., 2020b), less susceptibility to TTS was found as frequency
increased, whereas exposure frequencies below ~6.5 kHz showed an
increase in TTS susceptibility as frequency increased and approached
the region of best sensitivity. Kastelein et al. (2020b) showed a much
higher onset of TTS for a 88.5 kHz exposure as compared to lower
exposure frequencies (i.e., 16 kHz (Kastelein et al., 2019) 1.5 kHz and
6.5 kHz (Kastelein et al., 2020a)). For the 88.4 kHz test frequency, a
185 dB re 1 micropascal squared per second ([micro]Pa\2\-s) exposure
resulted in 3.6 dB of TTS, and a 191 dB re 1 [micro]Pa\2\-s exposure
produced 5.2 dB of TTS at 100 kHz and 5.4 dB of TTS at 125 kHz.
Together, these new studies demonstrate that the criteria for high-
frequency (HF) cetacean auditory impacts is likely to be conservative.
TTS can accumulate across multiple exposures, but the
resulting TTS will be less than the TTS from a single, continuous
exposure with the same SEL (Finneran et al., 2010a; Kastelein et al.,
2014b; Kastelein et al., 2015b; Mooney et al., 2009b). This means that
TTS predictions based on the total, cumulative SEL will overestimate
the amount of TTS from intermittent exposures such as sonars and
impulsive sources. The importance of duty cycle in predicting the
likelihood of TTS is demonstrated further in Kastelein et al. (2021b).
The authors found that reducing the duty cycle of a sound generally
reduced the potential for TTS in California sea lions, and that,
further, California sea lions are more susceptible to TTS than
previously believed at the 2 and 4 kHz frequencies tested.
The amount of observed TTS tends to decrease with
increasing time following the exposure; however, the relationship is
not monotonic (i.e., increasing exposure does not always increase TTS).
The time required for complete recovery of hearing depends on the
magnitude of the initial shift; for relatively small shifts recovery
may be complete in a few minutes, while large shifts (e.g.,
approximately 40 dB) may require several days for recovery. Recovery
times are consistent for similar-magnitude TTS, regardless of the type
of fatiguing sound exposure (impulsive, continuous noise band, or
sinusoidal wave; (Kastelein et al., 2019e)). Under many circumstances
TTS recovers linearly with the logarithm of time (Finneran et al.,
2010a, 2010b; Finneran and Schlundt, 2013; Kastelein et al., 2012a;
Kastelein et al., 2012b; Kastelein et al., 2013a; Kastelein et al.,
2014b; Kastelein et al., 2014c; Popov et al., 2011; Popov et al., 2013;
Popov et al., 2014). This means that for each doubling of recovery
time, the amount of TTS will decrease by the same amount (e.g., 6 dB
recovery per doubling of time). Please see Section 3.8.3.1.1.2 of the
2020 GOA DSEIS/OEIS for discussion of additional threshold shift
literature.
Nachtigall et al. (2018) and Finneran (2018) describe the
measurements of hearing sensitivity of multiple odontocete species
(bottlenose dolphin, harbor porpoise, beluga, and false killer whale)
when a relatively loud sound was preceded by a warning sound. These
captive animals were shown to reduce hearing sensitivity when warned of
an impending intense sound. Based on these experimental observations of
captive animals, the authors suggest that wild animals may dampen their
hearing during prolonged exposures or if conditioned to anticipate
intense sounds. Another study showed that echolocating animals
(including odontocetes) might have anatomical specializations that
might allow for conditioned hearing reduction and filtering of low-
frequency ambient noise, including increased stiffness and control of
middle ear structures and placement of inner ear structures (Ketten et
al., 2021). Finneran recommends further investigation of the mechanisms
of hearing sensitivity reduction in order to understand the
implications for interpretation of existing TTS data obtained from
captive animals, notably for considering TTS due to short duration,
unpredictable exposures.
Marine mammal hearing plays a critical role in communication with
conspecifics and in interpretation of environmental cues for purposes
such as predator avoidance and prey capture. Depending on the degree
(elevation of threshold in dB), duration (i.e., recovery time), and
frequency range of TTS, and the context in which it is experienced, TTS
can have effects on marine mammals ranging from discountable to
serious, similar to those discussed in auditory masking below. For
example, a marine mammal may be able to readily compensate for a brief,
relatively small amount of TTS in a non-critical frequency range that
takes place during a time where ambient noise is lower and there are
not as many competing sounds present. Alternatively, a larger amount
and longer duration of TTS sustained during a time when communication
is critical for successful mother/calf interactions could have more
serious impacts if it were in the same frequency band as the necessary
vocalizations and of a severity that impeded communication. Animals
exposed to high levels of sound that would be expected to result in
this physiological response would also be expected to have behavioral
responses of a
[[Page 49673]]
comparatively more severe or sustained nature, which is potentially
more significant than simple existence of a TTS. However, it is
important to note that TTS could occur due to longer exposures to sound
at lower levels so that a behavioral response may not be elicited.
Depending on the degree and frequency range, the effects of PTS on
an animal could also range in severity, although it is considered
generally more serious than TTS because it is a permanent condition. Of
note, reduced hearing sensitivity as a simple function of aging has
been observed in marine mammals, as well as humans and other taxa
(Southall et al., 2007), so we can infer that strategies exist for
coping with this condition to some degree, though likely not without
some cost to the animal.
Acoustically-Induced Bubble Formation Due to Sonars and Other Pressure-
Related Impacts
One theoretical cause of injury to marine mammals is rectified
diffusion (Crum and Mao, 1996), the process of increasing the size of a
bubble by exposing it to a sound field. This process could be
facilitated if the environment in which the ensonified bubbles exist is
supersaturated with gas. Repetitive diving by marine mammals can cause
the blood and some tissues to accumulate gas to a greater degree than
is supported by the surrounding environmental pressure (Ridgway and
Howard, 1979). The deeper and longer dives of some marine mammals (for
example, beaked whales) are theoretically predicted to induce greater
supersaturation (Houser et al., 2001b). If rectified diffusion were
possible in marine mammals exposed to high-level sound, conditions of
tissue supersaturation could theoretically speed the rate and increase
the size of bubble growth. Subsequent effects due to tissue trauma and
emboli would presumably mirror those observed in humans suffering from
decompression sickness.
It is unlikely that the short duration (in combination with the
source levels) of sonar pings would be long enough to drive bubble
growth to any substantial size, if such a phenomenon occurs. However,
an alternative but related hypothesis has also been suggested: stable
bubbles could be destabilized by high-level sound exposures such that
bubble growth then occurs through static diffusion of gas out of the
tissues. In such a scenario the marine mammal would need to be in a
gas-supersaturated state for a long enough period of time for bubbles
to become of a problematic size. Recent research with ex vivo
supersaturated bovine tissues suggested that, for a 37 kHz signal, a
sound exposure of approximately 215 dB referenced to (re) 1 [mu]Pa
would be required before microbubbles became destabilized and grew
(Crum et al., 2005). Assuming spherical spreading loss and a nominal
sonar source level of 235 dB re: 1 [mu]Pa at 1 m, a whale would need to
be within 10 m (33 ft) of the sonar dome to be exposed to such sound
levels. Furthermore, tissues in the study were supersaturated by
exposing them to pressures of 400-700 kilopascals for periods of hours
and then releasing them to ambient pressures. Assuming the
equilibration of gases with the tissues occurred when the tissues were
exposed to the high pressures, levels of supersaturation in the tissues
could have been as high as 400-700 percent. These levels of tissue
supersaturation are substantially higher than model predictions for
marine mammals (Houser et al., 2001; Saunders et al., 2008). It is
improbable that this mechanism is responsible for stranding events or
traumas associated with beaked whale strandings because both the degree
of supersaturation and exposure levels observed to cause microbubble
destabilization are unlikely to occur, either alone or in concert.
Yet another hypothesis (decompression sickness) has speculated that
rapid ascent to the surface following exposure to a startling sound
might produce tissue gas saturation sufficient for the evolution of
nitrogen bubbles (Jepson et al., 2003; Fernandez et al., 2005;
Fern[aacute]ndez et al., 2012). In this scenario, the rate of ascent
would need to be sufficiently rapid to compromise behavioral or
physiological protections against nitrogen bubble formation.
Alternatively, Tyack et al. (2006) studied the deep diving behavior of
beaked whales and concluded that: ``Using current models of breath-hold
diving, we infer that their natural diving behavior is inconsistent
with known problems of acute nitrogen supersaturation and embolism.''
Collectively, these hypotheses can be referred to as ``hypotheses of
acoustically mediated bubble growth.''
Although theoretical predictions suggest the possibility for
acoustically mediated bubble growth, there is considerable disagreement
among scientists as to its likelihood (Piantadosi and Thalmann, 2004;
Evans and Miller, 2003; Cox et al., 2006; Rommel et al., 2006). Crum
and Mao (1996) hypothesized that received levels would have to exceed
190 dB in order for there to be the possibility of significant bubble
growth due to supersaturation of gases in the blood (i.e., rectified
diffusion). Work conducted by Crum et al. (2005) demonstrated the
possibility of rectified diffusion for short duration signals, but at
SELs and tissue saturation levels that are highly improbable to occur
in diving marine mammals. To date, energy levels (ELs) predicted to
cause in vivo bubble formation within diving cetaceans have not been
evaluated (NOAA, 2002b). Jepson et al. (2003, 2005) and Fernandez et
al. (2004, 2005, 2012) concluded that in vivo bubble formation, which
may be exacerbated by deep, long-duration, repetitive dives may explain
why beaked whales appear to be relatively vulnerable to MF/HF sonar
exposures. It has also been argued that traumas from some beaked whale
strandings are consistent with gas emboli and bubble-induced tissue
separations (Jepson et al., 2003); however, there is no conclusive
evidence of this (Rommel et al., 2006). Based on examination of sonar-
associated strandings, Bernaldo de Quiros et al. (2019) list diagnostic
features, the presence of all of which suggest gas and fat embolic
syndrome for beaked whales stranded in association with sonar exposure.
As described in additional detail in the Nitrogen Decompression
subsection of the 2020 GOA DSEIS/OEIS, marine mammals generally are
thought to deal with nitrogen loads in their blood and other tissues,
caused by gas exchange from the lungs under conditions of high ambient
pressure during diving, through anatomical, behavioral, and
physiological adaptations (Hooker et al., 2012). Although not a direct
injury, variations in marine mammal diving behavior or avoidance
responses have been hypothesized to result in nitrogen off-gassing in
super-saturated tissues, possibly to the point of deleterious vascular
and tissue bubble formation (Hooker et al., 2012; Jepson et al., 2003;
Saunders et al., 2008) with resulting symptoms similar to decompression
sickness, however the process is still not well understood.
Fahlman et al. (2021) explained how stress can have a critical role
in causing the gas emboli present in stranded cetaceans. The authors
review decompression theory and the mechanisms dolphins have evolved to
prevent high N2 levels and gas emboli in normal conditions,
and describe how, in times of high stress, the selective gas exchange
hypothesis states that this mechanism can break down. In addition,
circulating microparticles may be a useful biomarker for decompression
stress in cetaceans. Velazquez-Wallraf et al. (2021) found that
individual variation also has an essential role in
[[Page 49674]]
this condition. To validate decompression sickness observations in
certain stranded cetaceans found coincident with naval activities, the
study used rabbits as an experimental pathological model and found that
rabbit mortalities during or immediately following decompression showed
systematically distributed gas bubbles (microscopic and macroscopic),
as well as emphysema and hemorrhages in multiple organs, similar to
observations in the stranded cetacean mortalities. Similar findings
were not found in almost half the rabbits that survived at least one
hour after decompression, revealing individual variation has an
essential role in this condition.
In 2009, Hooker et al. tested two mathematical models to predict
blood and tissue tension N2 (PN2) using field
data from three beaked whale species: northern bottlenose whales,
Cuvier's beaked whales, and Blainville's beaked whales. The researchers
aimed to determine if physiology (body mass, diving lung volume, and
dive response) or dive behavior (dive depth and duration, changes in
ascent rate, and diel behavior) would lead to differences in
PN2 levels and thereby decompression sickness risk between
species. In their study, they compared results for previously published
time depth recorder data (Hooker and Baird, 1999; Baird et al., 2006,
2008) from Cuvier's beaked whale, Blainville's beaked whale, and
northern bottlenose whale. They reported that diving lung volume and
extent of the dive response had a large effect on end-dive
PN2. Also, results showed that dive profiles had a larger
influence on end-dive PN2 than body mass differences between
species. Despite diel changes (i.e., variation that occurs regularly
every day or most days) in dive behavior, PN2 levels showed
no consistent trend. Model output suggested that all three species live
with tissue PN2 levels that would cause a significant
proportion of decompression sickness cases in terrestrial mammals. The
authors concluded that the dive behavior of Cuvier's beaked whale was
different from both Blainville's beaked whale and northern bottlenose
whale, and resulted in higher predicted tissue and blood N2
levels (Hooker et al., 2009). They also suggested that the prevalence
of Cuvier's beaked whales stranding after naval sonar exercises could
be explained by either a higher abundance of this species in the
affected areas or by possible species differences in behavior and/or
physiology related to MF active sonar (Hooker et al., 2009).
Bernaldo de Quiros et al. (2012) showed that, among stranded
whales, deep diving species of whales had higher abundances of gas
bubbles compared to shallow diving species. Kvadsheim et al. (2012)
estimated blood and tissue PN2 levels in species
representing shallow, intermediate, and deep diving cetaceans following
behavioral responses to sonar and their comparisons found that deep
diving species had higher end-dive blood and tissue N2
levels, indicating a higher risk of developing gas bubble emboli
compared with shallow diving species. Fahlmann et al. (2014) evaluated
dive data recorded from sperm, killer, long-finned pilot, Blainville's
beaked and Cuvier's beaked whales before and during exposure to low-
frequency (1-2 kHz), as defined by the authors, and mid-frequency (2-7
kHz) active sonar in an attempt to determine if either differences in
dive behavior or physiological responses to sonar are plausible risk
factors for bubble formation. The authors suggested that CO2
may initiate bubble formation and growth, while elevated levels of
N2 may be important for continued bubble growth. The authors
also suggest that if CO2 plays an important role in bubble
formation, a cetacean escaping a sound source may experience increased
metabolic rate, CO2 production, and alteration in cardiac
output, which could increase risk of gas bubble emboli. However, as
discussed in Kvadsheim et al. (2012), the actual observed behavioral
responses to sonar from the species in their study (sperm, killer,
long-finned pilot, Blainville's beaked, and Cuvier's beaked whales) did
not imply any significantly increased risk of decompression sickness
due to high levels of N2. Therefore, further information is
needed to understand the relationship between exposure to stimuli,
behavioral response (discussed in more detail below), elevated
N2 levels, and gas bubble emboli in marine mammals. The
hypotheses for gas bubble formation related to beaked whale strandings
is that beaked whales potentially have strong avoidance responses to MF
active sonars because they sound similar to their main predator, the
killer whale (Cox et al., 2006; Southall et al., 2007; Zimmer and
Tyack, 2007; Baird et al., 2008; Hooker et al., 2009). Further
investigation is needed to assess the potential validity of these
hypotheses.
To summarize, while there are several hypotheses, there is little
data directly connecting intense, anthropogenic underwater sounds with
non-auditory physical effects in marine mammals. The available data do
not support identification of a specific exposure level above which
non-auditory effects can be expected (Southall et al., 2007) or any
meaningful quantitative predictions of the numbers (if any) of marine
mammals that might be affected in these ways. In addition, such
effects, if they occur at all, would be expected to be limited to
situations where marine mammals are exposed to high powered sounds at
very close range over a prolonged period of time, which is not expected
to occur based on the speed of the vessels operating sonar in
combination with the speed and behavior of marine mammals in the
vicinity of sonar.
Injury Due to Sonar-Induced Acoustic Resonance
An object exposed to its resonant frequency will tend to amplify
its vibration at that frequency, a phenomenon called acoustic
resonance. Acoustic resonance has been proposed as a potential
mechanism by which a sonar or sources with similar operating
characteristics could damage tissues of marine mammals. In 2002, NMFS
convened a panel of government and private scientists to investigate
the potential for acoustic resonance to occur in marine mammals (NOAA,
2002). They modeled and evaluated the likelihood that Navy mid-
frequency sonar (2-10 kHz) caused resonance effects in beaked whales
that eventually led to their stranding. The workshop participants
concluded that resonance in air-filled structures was not likely to
have played a primary role in the Bahamas stranding in 2000. They
listed several reasons supporting this finding including (among
others): tissue displacements at resonance are estimated to be too
small to cause tissue damage; tissue-lined air spaces most susceptible
to resonance are too large in marine mammals to have resonant
frequencies in the ranges used by mid-frequency or low-frequency sonar;
lung resonant frequencies increase with depth, and tissue displacements
decrease with depth so if resonance is more likely to be caused at
depth it is also less likely to have an affect there; and lung tissue
damage has not been observed in any mass, multi-species stranding of
beaked whales. The frequency at which resonance was predicted to occur
in the animals' lungs was 50 Hz, well below the frequencies used by the
mid-frequency sonar systems associated with the Bahamas event. The
workshop participants focused on the March 2000 stranding of beaked
whales in the Bahamas as high-quality data were available, but the
workshop report notes that the results apply to other sonar-related
stranding events. For the reasons given by the
[[Page 49675]]
2002 workshop participants, we do not anticipate injury due to sonar-
induced acoustic resonance from the Navy's planned activities.
Physiological Stress
There is growing interest in monitoring and assessing the impacts
of stress responses to sound in marine animals. Classic stress
responses begin when an animal's central nervous system perceives a
potential threat to its homeostasis. That perception triggers stress
responses regardless of whether a stimulus actually threatens the
animal; the mere perception of a threat is sufficient to trigger a
stress response (Moberg, 2000; Sapolsky et al., 2005; Seyle, 1950).
Once an animal's central nervous system perceives a threat, it mounts a
biological response or defense that consists of a combination of the
four general biological defense responses: behavioral responses,
autonomic nervous system responses, neuroendocrine responses, or immune
responses.
According to Moberg (2000), in the case of many stressors, an
animal's first and sometimes most economical (in terms of biotic costs)
response is behavioral avoidance of the potential stressor or avoidance
of continued exposure to a stressor. An animal's second line of defense
to stressors involves the sympathetic part of the autonomic nervous
system and the classical ``fight or flight'' response which includes
the cardiovascular system, the gastrointestinal system, the exocrine
glands, and the adrenal medulla to produce changes in heart rate, blood
pressure, and gastrointestinal activity that humans commonly associate
with ``stress.'' These responses have a relatively short duration and
may or may not have significant long-term effect on an animal's
welfare.
An animal's third line of defense to stressors involves its
neuroendocrine systems or sympathetic nervous systems; the system that
has received the most study has been the hypothalmus-pituitary-adrenal
system (also known as the HPA axis in mammals or the hypothalamus-
pituitary-interrenal axis in fish and some reptiles). Unlike stress
responses associated with the autonomic nervous system, virtually all
neuro-endocrine functions that are affected by stress--including immune
competence, reproduction, metabolism, and behavior--are regulated by
pituitary hormones. Stress-induced changes in the secretion of
pituitary hormones have been implicated in failed reproduction (Moberg,
1987; Rivier and Rivest, 1991), altered metabolism (Elasser et al.,
2000), reduced immune competence (Blecha, 2000), and behavioral
disturbance (Moberg, 1987; Blecha, 2000). Increases in the circulation
of glucocorticosteroids (cortisol, corticosterone, and aldosterone in
marine mammals; see Romano et al., 2004) have been equated with stress
for many years.
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and distress is the biotic cost
of the response. During a stress response, an animal uses glycogen
stores that can be quickly replenished once the stress is alleviated.
In such circumstances, the cost of the stress response would not pose
serious fitness consequences. However, when an animal does not have
sufficient energy reserves to satisfy the energetic costs of a stress
response, energy resources must be diverted from other biotic
functions, which impairs those functions that experience the diversion.
For example, when a stress response diverts energy away from growth in
young animals, those animals may experience stunted growth. When a
stress response diverts energy from a fetus, an animal's reproductive
success and its fitness will suffer. In these cases, the animals will
have entered a pre-pathological or pathological state which is called
``distress'' (Seyle, 1950) or ``allostatic loading'' (McEwen and
Wingfield, 2003). This pathological state of distress will last until
the animal replenishes its energetic reserves sufficiently to restore
normal function. Note that these examples involved a long-term (days or
weeks) stress response exposure to stimuli.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments in both laboratory and free-ranging animals (for
examples see, Holberton et al., 1996; Hood et al., 1998; Jessop et al.,
2003; Krausman et al., 2004; Lankford et al., 2005; Reneerkens et al.,
2002; Thompson and Hamer, 2000). However, it should be noted (and as is
described in additional detail in the 2020 GOA DSEIS/OEIS) that our
understanding of the functions of various stress hormones (for example,
cortisol), is based largely upon observations of the stress response in
terrestrial mammals. Atkinson et al., 2015 note that the endocrine
response of marine mammals to stress may not be the same as that of
terrestrial mammals because of the selective pressures marine mammals
faced during their evolution in an ocean environment. For example, due
to the necessity of breath-holding while diving and foraging at depth,
the physiological role of epinephrine and norepinephrine (the
catecholamines) in marine mammals might be different than in other
mammals.
Marine mammals naturally experience stressors within their
environment and as part of their life histories. Changing weather and
ocean conditions, exposure to disease and naturally occurring toxins,
lack of prey availability, and interactions with predators all
contribute to the stress a marine mammal experiences (Atkinson et al.,
2015). Breeding cycles, periods of fasting, and social interactions
with members of the same species are also stressors, although they are
natural components of an animal's life history. Anthropogenic
activities have the potential to provide additional stressors beyond
those that occur naturally (Fair et al., 2014; Meissner et al., 2015;
Rolland et al., 2012). Anthropogenic stressors potentially include such
things as fishery interactions, pollution, tourism, and ocean noise.
Acoustically induced stress in marine mammals is not well
understood. There are ongoing efforts to improve our understanding of
how stressors impact marine mammal populations (e.g., King et al.,
2015; New et al., 2013a; New et al., 2013b; Pirotta et al., 2015a),
however little data exist on the consequences of sound-induced stress
response (acute or chronic). Factors potentially affecting a marine
mammal's response to a stressor include the individual's life history
stage, sex, age, reproductive status, overall physiological and
behavioral plasticity, and whether they are na[iuml]ve or experienced
with the sound (e.g., prior experience with a stressor may result in a
reduced response due to habituation (Finneran and Branstetter, 2013;
St. Aubin and Dierauf, 2001). Stress responses due to exposure to
anthropogenic sounds or other stressors and their effects on marine
mammals have been reviewed (Fair and Becker, 2000; Romano et al.,
2002b) and, more rarely, studied in wild populations (e.g., Romano et
al., 2002a). For example, Rolland et al. (2012) found that noise
reduction from reduced ship traffic in the Bay of Fundy was associated
with decreased stress in North Atlantic right whales. These and other
studies lead to a reasonable expectation that some marine mammals will
experience physiological stress responses upon exposure to acoustic
stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003).
[[Page 49676]]
Other research has also investigated the impact from vessels (both
whale-watching and general vessel traffic noise), and demonstrated
impacts do occur (Bain, 2002; Erbe, 2002; Lusseau, 2006; Williams et
al., 2006; Williams et al., 2009; Noren et al., 2009; Read et al.,
2014; Rolland et al., 2012; Skarke et al., 2014; Williams et al., 2013;
Williams et al., 2014a; Williams et al., 2014b; Pirotta et al., 2015b).
This body of research has generally investigated impacts associated
with the presence of chronic stressors, which differ significantly from
the proposed Navy training activities in the GOA Study Area. For
example, in an analysis of energy costs to killer whales, Williams et
al. (2009) suggested that whale-watching in Canada's Johnstone Strait
resulted in lost feeding opportunities due to vessel disturbance, which
could carry higher costs than other measures of behavioral change might
suggest. Ayres et al. (2012) reported on research in the Salish Sea
(Washington state) involving the measurement of southern resident
killer whale fecal hormones to assess two potential threats to the
species recovery: lack of prey (salmon) and impacts to behavior from
vessel traffic. Ayres et al. (2012) suggested that the lack of prey
overshadowed any population-level physiological impacts on southern
resident killer whales from vessel traffic. In a conceptual model
developed by the Population Consequences of Acoustic Disturbance (PCAD)
working group, serum hormones were identified as possible indicators of
behavioral effects that are translated into altered rates of
reproduction and mortality (NRC, 2005). The Office of Naval Research
hosted a workshop (Effects of Stress on Marine Mammals Exposed to
Sound) in 2009 that focused on this topic (ONR, 2009). Ultimately, the
PCAD working group issued a report (Cochrem, 2014) that summarized
information compiled from 239 papers or book chapters relating to
stress in marine mammals and concluded that stress responses can last
from minutes to hours and, while we typically focus on adverse stress
responses, stress response is part of a natural process to help animals
adjust to changes in their environment and can also be either neutral
or beneficial.
Most sound-induced stress response studies in marine mammals have
focused on acute responses to sound either by measuring catecholamines
or by measuring heart rate as an assumed proxy for an acute stress
response. Belugas demonstrated no catecholamine response to the
playback of oil drilling sounds (Thomas et al., 1990) but showed a
small but statistically significant increase in catecholamines
following exposure to impulsive sounds produced from a seismic water
gun (Romano et al., 2004). A bottlenose dolphin exposed to the same
seismic water gun signals did not demonstrate a catecholamine response,
but did demonstrate a statistically significant elevation in
aldosterone (Romano et al., 2004), albeit the increase was within the
normal daily variation observed in this species (St. Aubin et al.,
1996). Increases in heart rate were observed in bottlenose dolphins to
which known calls of other dolphins were played, although no increase
in heart rate was observed when background tank noise was played back
(Miksis et al., 2001). Unfortunately, in this study, it cannot be
determined whether the increase in heart rate was due to stress or an
anticipation of being reunited with the dolphin to which the
vocalization belonged. Similarly, a young beluga's heart rate was
observed to increase during exposure to noise, with increases dependent
upon the frequency band of noise and duration of exposure, and with a
sharp decrease to normal or below normal levels upon cessation of the
exposure (Lyamin et al., 2011). Spectral analysis of heart rate
variability corroborated direct measures of heart rate (Bakhchina et
al., 2017). This response might have been in part due to the conditions
during testing, the young age of the animal, and the novelty of the
exposure; a year later the exposure was repeated at a slightly higher
received level and there was no heart rate response, indicating the
beluga whale may have acclimated to the noise exposure. Kvadsheim et
al. (2010) measured the heart rate of captive hooded seals during
exposure to sonar signals and found an increase in the heart rate of
the seals during exposure periods versus control periods when the
animals were at the surface. When the animals dove, the normal dive-
related bradycardia (decrease in heart rate) was not impacted by the
sonar exposure. Elmegaard et al. (2021) found that sonar sweeps did not
elicit a startle response in captive harbor porpoises, but initial
exposures induced bradycardia, whereas impulse exposures induced
startle responses without a change in heart rate. The authors suggested
that the parasympathetic cardiac dive response may override any
transient sympathetic response, or that diving mammals may not have the
cardiac startle response seen in terrestrial mammals in order to
maintain volitional cardiovascular control at depth. Similarly,
Thompson et al. (1998) observed a rapid but short-lived decrease in
heart rates in harbor and grey seals exposed to seismic air guns (cited
in Gordon et al., 2003). Williams et al. (2017) monitored the heart
rates of narwhals released from capture and found that a profound dive
bradycardia persisted, even though exercise effort increased
dramatically as part of their escape response following release. Thus,
although some limited evidence suggests that tachycardia might occur as
part of the acute stress response of animals that are at the surface,
the dive bradycardia persists during diving and might be enhanced in
response to an acute stressor. Yang et al. (2021) measured cortisol
concentrations in two bottlenose dolphins and found significantly
higher concentrations after exposure to 140 dB re 1 [micro]Pa impulsive
noise playbacks. Two out of six tested indicators of immune system
function underwent acoustic dose-dependent changes, suggesting that
repeated exposures or sustained stress response to impulsive sounds may
increase an affected individual's susceptibility to pathogens. However,
exposing dolphins to a different acoustic stressor yielded contrasting
results. Houser et al. (2020) measured cortisol and epinephrine
obtained from 30 bottlenose dolphins exposed to simulated U.S. Navy
mid-frequency sonar and found no correlation between SPL and stress
hormone levels. In the same experiment (Houser et al., 2013b),
behavioral responses were shown to increase in severity with increasing
received SPLs. These results suggest that behavioral reactions to sonar
signals are not necessarily indicative of a hormonal stress response.
Houser et al. (2020) notes that additional research is needed to
determine the relationship between behavioral responses and
physiological responses.
Despite the limited amount of data available on sound-induced
stress responses for marine mammals exposed to anthropogenic sounds,
studies of other marine animals and terrestrial animals would also lead
us to expect that some marine mammals experience physiological stress
responses and, perhaps, physiological responses that would be
classified as ``distress'' upon exposure to high-frequency, mid-
frequency, and low-frequency sounds. For example, Jansen (1998)
reported on the relationship between acoustic exposures and
physiological responses that are indicative of stress responses in
humans (e.g., elevated respiration and increased heart rates). Jones
(1998) reported on reductions in human performance when faced with
acute,
[[Page 49677]]
repetitive exposures to acoustic disturbance. Trimper et al. (1998)
reported on the physiological stress responses of osprey to low-level
aircraft noise while Krausman et al. (2004) reported on the auditory
and physiological stress responses of endangered Sonoran pronghorn to
military overflights. However, take due to aircraft noise is not
anticipated as a result of the Navy's activities. Smith et al. (2004a,
2004b) identified noise-induced physiological transient stress
responses in hearing-specialist fish (i.e., goldfish) that accompanied
short- and long-term hearing losses. Welch and Welch (1970) reported
physiological and behavioral stress responses that accompanied damage
to the inner ears of fish and several mammals.
Auditory Masking
Sound can disrupt behavior through masking, or interfering with, an
animal's ability to detect, recognize, or discriminate between acoustic
signals of interest (e.g., those used for intraspecific communication
and social interactions, prey detection, predator avoidance, or
navigation) (Richardson et al., 1995; Erbe and Farmer, 2000; Tyack,
2000; Erbe et al., 2016). Masking occurs when the receipt of a sound is
interfered with by another coincident sound at similar frequencies and
at similar or higher intensity, and may occur whether the sound is
natural (e.g., snapping shrimp, wind, waves, precipitation) or
anthropogenic (e.g., shipping, sonar, seismic exploration) in origin.
As described in detail in the 2020 GOA DSEIS/OEIS, the ability of a
noise source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional discrimination, age, or TTS hearing loss),
and existing ambient noise and propagation conditions. Masking these
acoustic signals can disturb the behavior of individual animals, groups
of animals, or entire populations. Masking can lead to behavioral
changes including vocal changes (e.g., Lombard effect, increasing
amplitude, or changing frequency), cessation of foraging, and leaving
an area, to both signalers and receivers, in an attempt to compensate
for noise levels (Erbe et al., 2016).
In humans, significant masking of tonal signals occurs as a result
of exposure to noise in a narrow band of similar frequencies. As the
sound level increases, though, the detection of frequencies above those
of the masking stimulus decreases also. This principle is expected to
apply to marine mammals as well because of common biomechanical
cochlear properties across taxa.
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is man-made, it may be considered harassment
when disrupting natural behavioral patterns to the point where the
behavior is abandoned or significantly altered. It is important to
distinguish TTS and PTS, which persist after the sound exposure, from
masking, which only occurs during the sound exposure. Because masking
(without resulting in threshold shift) is not associated with abnormal
physiological function, it is not considered a physiological effect,
but rather a potential behavioral effect.
Richardson et al. (1995b) argued that the maximum radius of
influence of an industrial noise (including broadband low-frequency
sound transmission) on a marine mammal is the distance from the source
to the point at which the noise can barely be heard. This range is
determined by either the hearing sensitivity (including critical
ratios, or the lowest signal-to-noise ratio in which animals can detect
a signal, Finneran and Branstetter, 2013; Johnson et al., 1989;
Southall et al., 2000) of the animal or the background noise level
present. Industrial masking is most likely to affect some species'
ability to detect communication calls and natural sounds (i.e., surf
noise, prey noise, etc.; Richardson et al., 1995).
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009; Matthews et al., 2016) and may result in energetic
or other costs as animals change their vocalization behavior (e.g.,
Miller et al., 2000; Foote et al., 2004; Parks et al., 2007; Di Iorio
and Clark, 2009; Holt et al., 2009). Masking can be reduced in
situations where the signal and noise come from different directions
(Richardson et al., 1995), through amplitude modulation of the signal,
or through other compensatory behaviors (Houser and Moore, 2014).
Masking can be tested directly in captive species (e.g., Erbe, 2008),
but in wild populations it must be either modeled or inferred from
evidence of masking compensation. There are few studies addressing
real-world masking sounds likely to be experienced by marine mammals in
the wild (e.g., Branstetter et al., 2013).
The echolocation calls of toothed whales are subject to masking by
high-frequency sound. Human data indicate low-frequency sound can mask
high-frequency sounds (i.e., upward masking). Studies on captive
odontocetes by Au et al. (1974, 1985, 1993) indicate that some species
may use various processes to reduce masking effects (e.g., adjustments
in echolocation call intensity or frequency as a function of background
noise conditions). There is also evidence that the directional hearing
abilities of odontocetes are useful in reducing masking at the high-
frequencies these cetaceans use to echolocate, but not at the low-to-
moderate frequencies they use to communicate (Zaitseva et al., 1980). A
study by Nachtigall and Supin (2018) showed that false killer whales
adjust their hearing to compensate for ambient sounds and the intensity
of returning echolocation signals.
Impacts on signal detection, measured by masked detection
thresholds, are not the only important factors to address when
considering the potential effects of masking. As marine mammals use
sound to recognize conspecifics, prey, predators, or other biologically
significant sources (Branstetter et al., 2016), it is also important to
understand the impacts of masked recognition thresholds (often called
``informational masking''). Branstetter et al., 2016 measured masked
recognition thresholds for whistle-like sounds of bottlenose dolphins
and observed that they are approximately 4 dB above detection
thresholds (energetic masking) for the same signals. Reduced ability to
recognize a conspecific call or the acoustic signature of a predator
could have severe negative impacts. Branstetter et al., 2016 observed
that if ``quality communication'' is set at 90 percent recognition the
output of communication space models (which are based on 50 percent
detection) would likely result in a significant decrease in
communication range.
As marine mammals use sound to recognize predators (Allen et al.,
2014; Cummings and Thompson, 1971; Cur[eacute]
[[Page 49678]]
et al., 2015; Fish and Vania, 1971), the presence of masking noise may
also prevent marine mammals from responding to acoustic cues produced
by their predators, particularly if it occurs in the same frequency
band. For example, harbor seals that reside in the coastal waters off
British Columbia are frequently targeted by mammal-eating killer
whales. The seals acoustically discriminate between the calls of
mammal-eating and fish-eating killer whales (Deecke et al., 2002), a
capability that should increase survivorship while reducing the energy
required to attend to all killer whale calls. Similarly, sperm whales
(Cur[eacute] et al., 2016; Isojunno et al., 2016), long-finned pilot
whales (Visser et al., 2016), and humpback whales (Cur[eacute] et al.,
2015) changed their behavior in response to killer whale vocalization
playbacks; these findings indicate that some recognition of predator
cues could be missed if the killer whale vocalizations were masked. The
potential effects of masked predator acoustic cues depends on the
duration of the masking noise and the likelihood of a marine mammal
encountering a predator during the time that detection and recognition
of predator cues are impeded.
Redundancy and context can also facilitate detection of weak
signals. These phenomena may help marine mammals detect weak sounds in
the presence of natural or manmade noise. Most masking studies in
marine mammals present the test signal and the masking noise from the
same direction. The dominant background noise may be highly directional
if it comes from a particular anthropogenic source such as a ship or
industrial site. Directional hearing may significantly reduce the
masking effects of these sounds by improving the effective signal-to-
noise ratio.
Masking affects both senders and receivers of acoustic signals and
can potentially have long-term chronic effects on marine mammals at the
population level as well as at the individual level. Low-frequency
ambient sound levels have increased by as much as 20 dB (more than
three times in terms of SPL) in the world's ocean from pre-industrial
periods, with most of the increase from distant commercial shipping
(Hildebrand, 2009). All anthropogenic sound sources, but especially
chronic and lower-frequency signals (e.g., from commercial vessel
traffic), contribute to elevated ambient sound levels, thus
intensifying masking.
Impaired Communication
In addition to making it more difficult for animals to perceive and
recognize acoustic cues in their environment, anthropogenic sound
presents separate challenges for animals that are vocalizing. When they
vocalize, animals are aware of environmental conditions that affect the
``active space'' (or communication space) of their vocalizations, which
is the maximum area within which their vocalizations can be detected
before it drops to the level of ambient noise (Brenowitz, 2004; Brumm
et al., 2004; Lohr et al., 2003). Animals are also aware of
environmental conditions that affect whether listeners can discriminate
and recognize their vocalizations from other sounds, which is more
important than simply detecting that a vocalization is occurring
(Brenowitz, 1982; Brumm et al., 2004; Dooling, 2004, Marten and Marler,
1977; Patricelli et al., 2006). Anthropogenic sounds that reduce the
signal-to-noise ratio of animal vocalizations, increase the masked
auditory thresholds of animals listening for such vocalizations, or
reduce the active space of an animal's vocalizations, impair
communication between animals. Most species that vocalize have evolved
with an ability to make adjustments to their vocalizations to increase
the signal-to-noise ratio, active space, and recognizability/
distinguishability of their vocalizations in the face of temporary
changes in background noise (Brumm et al., 2004; Patricelli et al.,
2006). Vocalizing animals can make adjustments to vocalization
characteristics such as the frequency structure, amplitude, temporal
structure, and temporal delivery (repetition rate), or may cease to
vocalize.
Many animals will combine several of these strategies to compensate
for high levels of background noise. Although the fitness consequences
of vocal adjustments are not directly known in all instances, like most
other trade-offs animals must make, some of these strategies probably
come at a cost (Patricelli et al., 2006). Shifting songs and calls to
higher frequencies may also impose energetic costs (Lambrechts, 1996).
For example, in birds, vocalizing more loudly in noisy environments may
have energetic costs that decrease the net benefits of vocal adjustment
and alter a bird's energy budget (Brumm, 2004; Wood and Yezerinac,
2006).
Marine mammals are also known to make vocal changes in response to
anthropogenic noise. In cetaceans, vocalization changes have been
reported from exposure to anthropogenic noise sources such as sonar,
vessel noise, and seismic surveying (see the following for examples:
Gordon et al., 2003; Di Iorio and Clark, 2010; Hatch et al., 2012; Holt
et al., 2008; Holt et al., 2011; Lesage et al., 1999; McDonald et al.,
2009; Parks et al., 2007, Risch et al., 2012, Rolland et al., 2012), as
well as changes in the natural acoustic environment (Caruso et al.,
2020; Dunlop et al., 2014; Helble et al., 2020). Vocal changes can be
temporary, or can be persistent. For example, model simulation suggests
that the increase in starting frequency for the North Atlantic right
whale upcall over the last 50 years resulted in increased detection
ranges between right whales. The frequency shift, coupled with an
increase in call intensity by 20 dB, led to a call detectability range
of less than 3 km to over 9 km (Tennessen and Parks, 2016). Holt et al.
(2008) measured killer whale call source levels and background noise
levels in the one to 40 kHz band and reported that the whales increased
their call source levels by one dB SPL for every one dB SPL increase in
background noise level. Similarly, another study on St. Lawrence River
belugas reported a similar rate of increase in vocalization activity in
response to passing vessels (Scheifele et al., 2005). Di Iorio and
Clark (2010) showed that blue whale calling rates vary in association
with seismic sparker survey activity, with whales calling more on days
with surveys than on days without surveys. They suggested that the
whales called more during seismic survey periods as a way to compensate
for the elevated noise conditions.
In some cases, these vocal changes may have fitness consequences,
such as an increase in metabolic rates and oxygen consumption, as
observed in bottlenose dolphins when increasing their call amplitude
(Holt et al., 2015). A switch from vocal communication to physical,
surface-generated sounds such as pectoral fin slapping or breaching was
observed for humpback whales in the presence of increasing natural
background noise levels, indicating that adaptations to masking may
also move beyond vocal modifications (Dunlop et al., 2010).
While these changes all represent possible tactics by the sound-
producing animal to reduce the impact of masking, the receiving animal
can also reduce masking by using active listening strategies such as
orienting to the sound source, moving to a quieter location, or
reducing self-noise from hydrodynamic flow by remaining still. The
temporal structure of noise (e.g., amplitude modulation) may also
provide a considerable release from masking through comodulation
masking release (a reduction of masking that occurs when broadband
noise, with a frequency spectrum wider than an animal's auditory filter
bandwidth at the
[[Page 49679]]
frequency of interest, is amplitude modulated) (Branstetter and
Finneran, 2008; Branstetter et al., 2013). Signal type (e.g., whistles,
burst-pulse, sonar clicks) and spectral characteristics (e.g.,
frequency modulated with harmonics) may further influence masked
detection thresholds (Branstetter et al., 2016; Cunningham et al.,
2014).
Masking Due to Sonar and Other Transducers
The functional hearing ranges of mysticetes, odontocetes, and
pinnipeds underwater overlap the frequencies of the sonar sources used
in the Navy's low-frequency active sonar (LFAS)/mid-frequency active
sonar (MFAS)/high-frequency active sonar (HFAS) training exercises
(though the Navy proposes no LFAS use for the activities in this
rulemaking). Additionally, almost all affected species' vocal
repertoires span across the frequencies of these sonar sources used by
the Navy. The closer the characteristics of the masking signal to the
signal of interest, the more likely masking is to occur. Masking by
mid-frequency active sonar (MFAS) with relatively low-duty cycles is
not anticipated (or would be of very short duration) for most cetaceans
as sonar signals occur over a relatively short duration and narrow
bandwidth (overlapping with only a small portion of the hearing range).
While dolphin whistles and MFAS are similar in frequency, masking is
not anticipated (or would be of very short duration) due to the low-
duty cycle of most sonars.
As described in the 2020 GOA DSEIS/OEIS, newer high-duty cycle or
continuous active sonars have more potential to mask vocalizations.
These sonars transmit more frequently (greater than 80 percent duty
cycle) than traditional sonars, but at a substantially lower source
level. HFAS, such as pingers that operate at higher repetition rates
(e.g., 2-10 kHz with harmonics up to 19 kHz, 76 to 77 pings per minute)
(Culik et al., 2001), also operate at lower source levels and have
faster attenuation rates due to the higher frequencies used. These
lower source levels limit the range of impacts, however compared to
traditional sonar systems, individuals close to the source are likely
to experience masking at longer time scales. The frequency range at
which high-duty cycle systems operate overlaps the vocalization
frequency of many mid-frequency cetaceans. Continuous noise at the same
frequency of communicative vocalizations may cause disruptions to
communication, social interactions, acoustically mediated cooperative
behaviors, and important environmental cues. There is also the
potential for the mid-frequency sonar signals to mask important
environmental cues (e.g., predator or conspecific acoustic cues),
possibly affecting survivorship for targeted animals. Masking due to
high duty cycle sonars is likely analogous to masking produced by other
continuous sources (e.g., vessel noise and low-frequency cetaceans),
and would likely have similar short-term consequences, though longer in
duration due to the duration of the masking noise. A study by von
Benda-Beckmann et al. (2021) modeled the effect of pulsed and
continuous 1-2 kHz active sonar on sperm whale echolocation clicks, and
found that the presence of upper harmonics in the sonar signal
increased masking of clicks produced in the search phase of foraging
compared to buzz clicks produced during prey capture. Different levels
of sonar caused intermittent to continuous masking (120 to 160 dB re 1
[mu]Pa2, respectively), but varied based on click level, whale
orientation, and prey target strength. Continuous active sonar resulted
in a greater percentage of time that echolocation clicks were masked
compared to pulsed active sonar. Other short-term consequences may
include changes to vocalization amplitude and frequency (Brumm and
Slabbekoorn, 2005; Hotchkin and Parks, 2013) and behavioral impacts
such as avoidance of the area and interruptions to foraging or other
essential behaviors (Gordon et al., 2003; Isojunno et al., 2021). Long-
term consequences could include changes to vocal behavior and
vocalization structure (Foote et al., 2004; Parks et al., 2007),
abandonment of habitat if masking occurs frequently enough to
significantly impair communication (Brumm and Slabbekoorn, 2005), a
potential decrease in survivorship if predator vocalizations are masked
(Brumm and Slabbekoorn, 2005), and a potential decrease in recruitment
if masking interferes with reproductive activities or mother-calf
communication (Gordon et al., 2003).
Masking Due to Vessel Noise
Masking is more likely to occur in the presence of broadband,
relatively continuous noise sources such as vessels. Several studies
have shown decreases in marine mammal communication space and changes
in behavior as a result of the presence of vessel noise. For example,
right whales were observed to shift the frequency content of their
calls upward while reducing the rate of calling in areas of increased
anthropogenic noise (Parks et al., 2007) as well as increasing the
amplitude (intensity) of their calls (Parks, 2009; Parks et al., 2011).
Fournet et al. (2018) observed that humpback whales in Alaska responded
to increasing ambient sound levels (natural and anthropogenic) by
increasing the source levels of their calls (non-song vocalizations).
Clark et al. (2009) also observed that right whales communication space
decreased by up to 84 percent in the presence of vessels (Clark et al.,
2009). Cholewiak et al. (2018) also observed loss in communication
space in Stellwagen National Marine Sanctuary for North Atlantic right
whales, fin whales, and humpback whales with increased ambient noise
and shipping noise. Gabriele et al. (2018) modeled the effects of
vessel traffic sound on communication space in Glacier Bay National
Park in Alaska and found that typical summer vessel traffic in the
National Park causes losses of communication space to singing whales
(reduced by 13-28 percent), calling whales (18-51 percent), and roaring
seals (32-61 percent), particularly during daylight hours and even in
the absence of cruise ships. Dunlop (2019) observed that an increase in
vessel noise reduced modelled communication space and resulted in
significant reduction in group social interactions in Australian
humpback whales. However, communication signal masking did not fully
explain this change in social behavior in the model, indicating there
may also be an additional effect of the physical presence of the vessel
on social behavior (Dunlop, 2019). Although humpback whales off
Australia did not change the frequency or duration of their
vocalizations in the presence of ship noise, their source levels were
lower than expected based on source level changes to wind noise,
potentially indicating some signal masking (Dunlop, 2016). Multiple
delphinid species have also been shown to increase the minimum or
maximum frequencies of their whistles in the presence of anthropogenic
noise and reduced communication space (for examples see: Holt et al.,
2008; Holt et al., 2011; Gervaise et al., 2012; Williams et al., 2013;
Hermannsen et al., 2014; Papale et al., 2015; Liu et al., 2017; Pine et
al., 2021).
Behavioral Response/Disturbance
Behavioral responses to sound are highly variable and context-
specific. Many different variables can influence an animal's perception
of and response to (nature and magnitude) an acoustic event. An
animal's prior experience with a sound or sound source affects whether
it is less likely (habituation) or more likely (sensitization) to
respond to certain sounds in the future (animals
[[Page 49680]]
can also be innately predisposed to respond to certain sounds in
certain ways) (Southall et al., 2007). Related to the sound itself, the
perceived nearness of the sound, bearing of the sound (approaching vs.
retreating), the similarity of a sound to biologically relevant sounds
in the animal's environment (i.e., calls of predators, prey, or
conspecifics), and familiarity of the sound may affect the way an
animal responds to the sound (Southall et al., 2007; DeRuiter et al.,
2013). Individuals (of different age, gender, reproductive status,
etc.) among most populations will have variable hearing capabilities,
and differing behavioral sensitivities to sounds that will be affected
by prior conditioning, experience, and current activities of those
individuals. Often, specific acoustic features of the sound and
contextual variables (i.e., proximity, duration, or recurrence of the
sound, or the current behavior that the marine mammal is engaged in or
its prior experience), as well as entirely separate factors such as the
physical presence of a nearby vessel, may be more relevant to the
animal's response than the received level alone. For example, Goldbogen
et al. (2013) demonstrated that individual behavioral state was
critically important in determining response of blue whales to sonar,
noting that some individuals engaged in deep (>50 m) feeding behavior
had greater dive responses than those in shallow feeding or non-feeding
conditions. Some blue whales in the Goldbogen et al. (2013) study that
were engaged in shallow feeding behavior demonstrated no clear changes
in diving or movement even when received levels (RLs) were high (~160
dB re: 1[micro]Pa) for exposures to 3-4 kHz sonar signals, while others
showed a clear response at exposures at lower received levels of sonar
and pseudorandom noise.
Studies by DeRuiter et al. (2012) indicate that variability of
responses to acoustic stimuli depends not only on the species receiving
the sound and the sound source, but also on the social, behavioral, or
environmental contexts of exposure. Another study by DeRuiter et al.
(2013) examined behavioral responses of Cuvier's beaked whales to MF
sonar and found that whales responded strongly at low received levels
(RL of 89-127 dB re: 1[micro]Pa) by ceasing normal fluking and
echolocation, swimming rapidly away, and extending both dive duration
and subsequent non-foraging intervals when the sound source was 3.4-9.5
km away. Importantly, this study also showed that whales exposed to a
similar range of received levels (78-106 dB re: 1 [micro]Pa) from
distant sonar exercises (118 km away) did not elicit such responses,
suggesting that context may moderate reactions.
Ellison et al. (2012) outlined an approach to assessing the effects
of sound on marine mammals that incorporates contextual-based factors.
The authors recommend considering not just the received level of sound,
but also the activity the animal is engaged in at the time the sound is
received, the nature and novelty of the sound (i.e., is this a new
sound from the animal's perspective), and the distance between the
sound source and the animal. They submit that this ``exposure
context,'' as described, greatly influences the type of behavioral
response exhibited by the animal. Forney et al. (2017) also point out
that an apparent lack of response (e.g., no displacement or avoidance
of a sound source) may not necessarily mean there is no cost to the
individual or population, as some resources or habitats may be of such
high value that animals may choose to stay, even when experiencing
stress or hearing loss. Forney et al. (2017) recommend considering both
the costs of remaining in an area of noise exposure such as TTS, PTS,
or masking, which could lead to an increased risk of predation or other
threats or a decreased capability to forage, and the costs of
displacement, including potential increased risk of vessel strike,
increased risks of predation or competition for resources, or decreased
habitat suitable for foraging, resting, or socializing. This sort of
contextual information is challenging to predict with accuracy for
ongoing activities that occur over large spatial and temporal expanses.
However, distance is one contextual factor for which data exist to
quantitatively inform a take estimate, and the method for predicting
Level B harassment in this rule does consider distance to the source.
Other factors are often considered qualitatively in the analysis of the
likely consequences of sound exposure, where supporting information is
available.
Friedlaender et al. (2016) provided the first integration of direct
measures of prey distribution and density variables incorporated into
across-individual analyses of behavior responses of blue whales to
sonar, and demonstrated a five-fold increase in the ability to quantify
variability in blue whale diving behavior. These results illustrate
that responses evaluated without such measurements for foraging animals
may be misleading, which again illustrates the context-dependent nature
of the probability of response.
Exposure of marine mammals to sound sources can result in, but is
not limited to, no response or any of the following observable
responses: increased alertness; orientation or attraction to a sound
source; vocal modifications; cessation of feeding; cessation of social
interaction; alteration of movement or diving behavior; habitat
abandonment (temporary or permanent); and, in severe cases, panic,
flight, stampede, or stranding, potentially resulting in death
(Southall et al., 2007; Southall et al., 2021). A review of marine
mammal responses to anthropogenic sound was first conducted by
Richardson (1995). More recent reviews (Nowacek et al., 2007; DeRuiter
et al., 2012 and 2013; Ellison et al., 2012; Gomez et al., 2016)
address studies conducted since 1995 and focused on observations where
the received sound level of the exposed marine mammal(s) was known or
could be estimated. Gomez et al. (2016) conducted a review of the
literature considering the contextual information of exposure in
addition to received level and found that higher received levels were
not always associated with more severe behavioral responses and vice
versa. Southall et al. (2016) states that results demonstrate that some
individuals of different species display clear yet varied responses,
some of which have negative implications, while others appear to
tolerate high levels, and that responses may not be fully predictable
with simple acoustic exposure metrics (e.g., received sound level).
Rather, the authors state that differences among species and
individuals along with contextual aspects of exposure (e.g., behavioral
state) appear to affect response probability.
Sperm whales were exposed to pulsed active sonar (1-2 kHz) at
moderate source levels and high source levels, as well as continuously
active sonar at moderate levels for which the summed energy (SEL)
equaled the summed energy of the high source level pulsed sonar
(Isojunno et al., 2020). Foraging behavior did not change during
exposures to moderate source level sonar, but non-foraging behavior
increased during exposures to high source level sonar and to the
continuous sonar, indicating that the energy of the sound (the SEL) was
a better predictor of response than SPL. However, the time of day of
the exposure was also an important covariate in determining the amount
of non-foraging behavior, as were order effects (e.g. the SEL of the
previous exposure). Isojunno et al. (2021) found that higher SELs
reduced
[[Page 49681]]
sperm whale buzzing (i.e., foraging). Duration of continuous sonar
activity also appears to impact sperm whale displacement and foraging
activity (Stanistreet, 2022). During long bouts of sonar lasting up to
13 consecutive hours, occurring repeatedly over an 8 day naval exercise
(median and maximum SPL = 120 dB and 164 dB), sperm whales
substantially reduced how often they produced clicks during sonar,
indicating a decrease or cessation in foraging behavior. Few previous
studies have shown sustained changes in sperm whales, but there was an
absence of sperm whale clicks for 6 consecutive days of sonar activity.
Cur[eacute] et al. (2021) also found that sperm whales exposed to
continuous and pulsed active sonar were more likely to produce low or
medium severity responses with higher cumulative SEL. Specifically, the
probability of observing a low severity response increased to 0.5 at
approximately 173 dB SEL and observing a medium severity response
reached a probability of 0.35 at cumulative SELs between 179 and 189
dB. These results again demonstrate that the behavioral state and
environment of the animal mediates the likelihood of a behavioral
response, as do the characteristics (e.g., frequency, energy level) of
the sound source itself.
The following subsections provide examples of behavioral responses
that provide an idea of the variability in behavioral responses that
would be expected given the differential sensitivities of marine mammal
species to sound and the wide range of potential acoustic sources to
which a marine mammal may be exposed. Behavioral responses that could
occur for a given sound exposure should be determined from the
literature that is available for each species, or extrapolated from
closely related species when no information exists, along with
contextual factors.
Flight Response
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996). The result of a flight response could range from
brief, temporary exertion and displacement from the area where the
signal provokes flight to, in extreme cases, being a component of
marine mammal strandings associated with sonar activities (Evans and
England, 2001). If marine mammals respond to Navy vessels that are
transmitting active sonar in the same way that they might respond to a
predator, their probability of flight responses should increase when
they perceive that Navy vessels are approaching them directly, because
a direct approach may convey detection and intent to capture (Burger
and Gochfeld, 1981, 1990; Cooper, 1997, 1998). There are limited data
on flight response for marine mammals in water; however, there are
examples of this response in species on land. For instance, the
probability of flight responses in Dall's sheep Ovis dalli dalli (Frid,
2001), hauled-out ringed seals Phoca hispida (Born et al., 1999),
Pacific brant (Branta bernicl nigricans), and Canada geese (B.
canadensis) increased as a helicopter or fixed-wing aircraft more
directly approached groups of these animals (Ward et al., 1999). Bald
eagles (Haliaeetus leucocephalus) perched on trees alongside a river
were also more likely to flee from a paddle raft when their perches
were closer to the river or were closer to the ground (Steidl and
Anthony, 1996).
Response to Predator
As discussed earlier, evidence suggests that at least some marine
mammals have the ability to acoustically identify potential predators.
For example, harbor seals that reside in the coastal waters off British
Columbia are frequently targeted by certain groups of killer whales,
but not others. The seals discriminate between the calls of threatening
and non-threatening killer whales (Deecke et al., 2002), a capability
that should increase survivorship while reducing the energy required
for attending to and responding to all killer whale calls. The
occurrence of masking or hearing impairment provides a means by which
marine mammals may be prevented from responding to the acoustic cues
produced by their predators. Whether or not this is a possibility
depends on the duration of the masking/hearing impairment and the
likelihood of encountering a predator during the time that predator
cues are impeded.
Alteration of Diving or Movement
Changes in dive behavior can vary widely. They may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Ng and Leung, 2003; Nowacek et al. 2004; Goldbogen et
al., 2013a, 2013b). Variations in dive behavior may reflect
interruptions in biologically significant activities (e.g., foraging)
or they may be of little biological significance. Variations in dive
behavior may also expose an animal to potentially harmful conditions
(e.g., increasing the chance of ship-strike) or may serve as an
avoidance response that enhances survivorship. The impact of a
variation in diving resulting from an acoustic exposure depends on what
the animal is doing at the time of the exposure and the type and
magnitude of the response.
Nowacek et al. (2004) reported disruptions of dive behaviors in
foraging North Atlantic right whales when exposed to an alerting
stimulus, an action, they noted, that could lead to an increased
likelihood of ship strike. However, the whales did not respond to
playbacks of either right whale social sounds or vessel noise,
highlighting the importance of the sound characteristics in producing a
behavioral reaction. Conversely, Indo-Pacific humpback dolphins have
been observed to dive for longer periods of time in areas where vessels
were present and/or approaching (Ng and Leung, 2003). In both of these
studies, the influence of the sound exposure cannot be decoupled from
the physical presence of a surface vessel, thus complicating
interpretations of the relative contribution of each stimulus to the
response. Indeed, the presence of surface vessels, their approach, and
speed of approach, seemed to be significant factors in the response of
the Indo-Pacific humpback dolphins (Ng and Leung, 2003). Arranz et al.
(2021) attempted to distinguish effects of vessel noise from vessel
presence by conducting a noise exposure experiment which compared
behavioral reactions of resting short-finned pilot whale mother-calf
pairs during controlled approaches by a tour boat with two electric
(136-140 dB) or petrol engines (139-150 dB). Approach speed (<4 knots),
distance of passes (60 m), and vessel features other than engine noise
remained the same between the two experimental conditions. Behavioral
data was collected via unmanned aerial vehicle and activity budgets
were calculated from continuous focal follows. Mother pilot whales
rested less and calves nursed less in response to both types of boat
engines compared to control conditions (vessel >300 m, stationary in
neutral). However, they found no significant impact on whale behaviors
when the boat approached with the quieter electric engine, while
resting
[[Page 49682]]
behavior decreased 29 percent and nursing decreased 81 percent when the
louder petrol engine was installed in the same vessel. Low-frequency
signals of the Acoustic Thermometry of Ocean Climate (ATOC) sound
source were not found to affect dive times of humpback whales in
Hawaiian waters (Frankel and Clark, 2000) or to overtly affect elephant
seal dives (Costa et al., 2003). They did, however, produce subtle
effects that varied in direction and degree among the individual seals,
illustrating the equivocal nature of behavioral effects and consequent
difficulty in defining and predicting them. Lastly, as noted
previously, DeRuiter et al. (2013) noted that distance from a sound
source may moderate marine mammal reactions in their study of Cuvier's
beaked whales, which showed the whales swimming rapidly and silently
away when a sonar signal was 3.4-9.5 km away while showing no such
reaction to the same signal when the signal was 118 km away even though
the received levels were similar.
Foraging
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Harris et al., 2017; Madsen et al., 2006a; Nowacek et al.; 2004;
Yazvenko et al., 2007). A determination of whether foraging disruptions
incur fitness consequences would require information on or estimates of
the energetic requirements of the affected individuals and the
relationship between prey availability, foraging effort and success,
and the life history stage of the animal.
Southall et al. (2019a) found that prey availability was higher in
the western area of the Southern California Offshore Range where
Cuvier's beaked whales preferentially occurred, while prey resources
were lower in the eastern area and moderate in the area just north of
the Range. This high prey availability may indicate that fewer foraging
dives are needed to meet metabolic energy requirements than would be
needed in another area with fewer resources. Benoit-Bird et al. (2020)
demonstrated that differences in squid distribution could be a
substantial factor for beaked whales' habitat preference. The
researchers suggest that this be considered when comparing beaked whale
habitat use both on and off Navy ranges.
Noise from seismic surveys was not found to impact the feeding
behavior in western grey whales off the coast of Russia (Yazvenko et
al., 2007). Visual tracking, passive acoustic monitoring, and movement
recording tags were used to quantify sperm whale behavior prior to,
during, and following exposure to air gun arrays at received levels in
the range of 140-160 dB at distances of 7-13 km, following a phase-in
of sound intensity and full array exposures at 1-13 km (Madsen et al.,
2006a; Miller et al., 2009). Sperm whales did not exhibit horizontal
avoidance behavior at the surface. However, foraging behavior may have
been affected. The sperm whales exhibited 19 percent less vocal (buzz)
rate during full exposure relative to post exposure, and the whale that
was approached most closely had an extended resting period and did not
resume foraging until the air guns had ceased firing. The remaining
whales continued to execute foraging dives throughout exposure;
however, swimming movements during foraging dives were six percent
lower during exposure than control periods (Miller et al., 2009). These
data raise concerns that air gun surveys may impact foraging behavior
in sperm whales, although more data are required to understand whether
the differences were due to exposure or natural variation in sperm
whale behavior (Miller et al., 2009).
Balaenopterid whales exposed to moderate low-frequency signals
similar to the ATOC sound source demonstrated no variation in foraging
activity (Croll et al., 2001), whereas five out of six North Atlantic
right whales exposed to an acoustic alarm interrupted their foraging
dives (Nowacek et al., 2004). Although the received SPLs were similar
in the latter two studies, the frequency, duration, and temporal
pattern of signal presentation were different. These factors, as well
as differences in species sensitivity, are likely contributing factors
to the differential response. Blue whales exposed to mid-frequency
sonar in the Southern California Bight were less likely to produce low
frequency calls usually associated with feeding behavior (Melc[oacute]n
et al., 2012). However, Melc[oacute]n et al. (2012) were unable to
determine if suppression of low frequency calls reflected a change in
their feeding performance or abandonment of foraging behavior and
indicated that implications of the documented responses are unknown.
Further, it is not known whether the lower rates of calling actually
indicated a reduction in feeding behavior or social contact since the
study used data from remotely deployed, passive acoustic monitoring
buoys. In contrast, blue whales increased their likelihood of calling
when ship noise was present, and decreased their likelihood of calling
in the presence of explosive noise, although this result was not
statistically significant (Melc[oacute]n et al., 2012). Additionally,
the likelihood of an animal calling decreased with the increased
received level of mid-frequency sonar, beginning at a SPL of
approximately 110-120 dB re: 1 [micro]Pa (Melc[oacute]n et al., 2012).
Results from behavioral response studies in Southern California waters
indicated that, in some cases and at low received levels, tagged blue
whales responded to mid-frequency sonar but that those responses were
generally brief, of low to moderate severity, and highly dependent on
exposure context (Southall et al., 2011; Southall et al., 2012b;
Southall et al., 2019b). Information on or estimates of the energetic
requirements of the individuals and the relationship between prey
availability, foraging effort and success, and the life history stage
of the animal will help better inform a determination of whether
foraging disruptions incur fitness consequences. Surface feeding blue
whales did not show a change in behavior in response to mid-frequency
simulated and real sonar sources with received levels between 90 and
179 dB re: 1 [micro]Pa, but deep feeding and non-feeding whales showed
temporary reactions including cessation of feeding, reduced initiation
of deep foraging dives, generalized avoidance responses, and changes to
dive behavior. The behavioral responses the researchers observed were
generally brief, of low to moderate severity, and highly dependent on
exposure context (behavioral state, source-to-whale horizontal range,
and prey availability) (DeRuiter et al., 2017; Goldbogen et al., 2013b;
Sivle et al., 2015). Goldbogen et al. (2013b) indicate that disruption
of feeding and displacement could impact individual fitness and health.
However, for this to be true, we would have to assume that an
individual whale could not compensate for this lost feeding opportunity
by either immediately feeding at another location, by feeding shortly
after cessation of acoustic exposure, or by feeding at a later time.
There is no indication this is the case, particularly since unconsumed
prey would likely still be available in the environment in most cases
following the cessation of acoustic exposure.
[[Page 49683]]
Similarly, while the rates of foraging lunges decrease in humpback
whales due to sonar exposure, there was variability in the response
across individuals, with one animal ceasing to forage completely and
another animal starting to forage during the exposure (Sivle et al.,
2016). In addition, almost half of the animals that exhibited avoidance
behavior were foraging before the exposure but the others were not; the
animals that exhibited avoidance behavior while not feeding responded
at a slightly lower received level and greater distance than those that
were feeding (Wensveen et al., 2017). These findings indicate that the
behavioral state of the animal plays a role in the type and severity of
a behavioral response. In fact, when the prey field was mapped and used
as a covariate in similar models looking for a response in the same
blue whales, the response in deep-feeding behavior by blue whales was
even more apparent, reinforcing the need for contextual variables to be
included when assessing behavioral responses (Friedlaender et al.,
2016).
Breathing
Respiration naturally varies with different behaviors and
variations in respiration rate as a function of acoustic exposure can
be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Mean exhalation rates of gray whales at rest and while
diving were found to be unaffected by seismic surveys conducted
adjacent to the whale feeding grounds (Gailey et al., 2007).
Studies with captive harbor porpoises showed increased respiration
rates upon introduction of acoustic alarms (Kastelein et al., 2001;
Kastelein et al., 2006a) and emissions for underwater data transmission
(Kastelein et al., 2005). Harbor porpoises did not respond to the low-
duty cycle mid-frequency tones at any received level, but one did
respond to the high-duty cycle signal with more jumping and increased
respiration rates (Kastelein et al., 2018b). Harbor porpoises responded
to seal scarers with broadband signals up to 44 kHz with a slight
respiration response at 117 dB re 1 [micro]Pa and an avoidance response
at 139 dB re 1 [micro]Pa, but another scarer with a fundamental
(strongest) frequency of 18 kHz did not have an avoidance response
until 151 dB re 1 [micro]Pa (Kastelein et al., 2015e). However,
exposure of the same acoustic alarm to a striped dolphin under the same
conditions did not elicit a response (Kastelein et al., 2006a), again
highlighting the importance in understanding species differences in the
tolerance of underwater noise when determining the potential for
impacts resulting from anthropogenic sound exposure. Lastly, Kastelein
et al. (2019a) examined the potential masking effect of high sea state
ambient noise on captive harbor porpoise perception of and response to
high duty cycle playbacks of AN/SQS-53C sonar signals by observing
their respiration rates. Results indicated that sonar signals were not
masked by the high sea state noise, and received levels at which
responses were observed were similar to those observed in prior studies
of harbor porpoise behavior.
Pilot whales exhibited reduced breathing rates relative to their
diving behavior when the low frequency active sonar levels were high
(reaching 180 dB re 1 [micro]Pa), but only on the first sonar exposure;
on subsequent exposures their breathing rates increased (Isojunno et
al., 2018), indicating a change in response tactic with additional
exposures.
Social Relationships
Social interactions between mammals can be affected by noise via
the disruption of communication signals or by the displacement of
individuals. Disruption of social relationships therefore depends on
the disruption of other behaviors (e.g., avoidance, masking, etc.).
Sperm whales responded to military sonar, apparently from a submarine,
by dispersing from social aggregations, moving away from the sound
source, remaining relatively silent, and becoming difficult to approach
(Watkins et al., 1985). In contrast, sperm whales in the Mediterranean
that were exposed to submarine sonar continued calling (J. Gordon pers.
comm. cited in Richardson et al., 1995). Long-finned pilot whales
exposed to three types of disturbance--playbacks of killer whale
sounds, naval sonar exposure, and tagging--resulted in increased group
sizes (Visser et al., 2016). In response to sonar, pilot whales also
spent more time at the surface with other members of the group (Visser
et al., 2016). However, social disruptions must be considered in
context of the relationships that are affected. While some disruptions
may not have deleterious effects, others, such as long-term or repeated
disruptions of mother/calf pairs or interruption of mating behaviors,
have the potential to affect the growth and survival or reproductive
effort/success of individuals.
Vocalizations (Also see Auditory Masking Section)
Vocal changes in response to anthropogenic noise can occur across
the repertoire of sound production modes used by marine mammals, such
as whistling, echolocation click production, calling, and singing.
Changes in vocalization behavior that may result in response to
anthropogenic noise can occur for any of these modes and may result
from a need to compete with an increase in background noise or may
reflect an increased vigilance or a startle response. For example, in
the presence of potentially masking signals (low-frequency active
sonar), humpback whales have been observed to increase the length of
their songs (Miller et al., 2000; Fristrup et al., 2003). A similar
compensatory effect for the presence of low-frequency vessel noise has
been suggested for right whales; right whales have been observed to
shift the frequency content of their calls upward while reducing the
rate of calling in areas of increased anthropogenic noise (Parks et
al., 2007; Rolland et al., 2012). Killer whales off the northwestern
coast of the United States have been observed to increase the duration
of primary calls once a threshold in observing vessel density (e.g.,
whale watching) was reached, which has been suggested as a response to
increased masking noise produced by the vessels (Foote et al., 2004;
NOAA, 2014). In contrast, both sperm and pilot whales potentially
ceased sound production during the Heard Island feasibility test
(Bowles et al., 1994), although it cannot be absolutely determined
whether the inability to acoustically detect the animals was due to the
cessation of sound production or the displacement of animals from the
area.
Cerchio et al. (2014) used passive acoustic monitoring to document
the presence of singing humpback whales off the coast of northern
Angola and to opportunistically test for the effect of seismic survey
activity on the number of singing whales. Two recording units were
deployed between March and December 2008 in the offshore environment;
numbers of singers were counted every hour. Generalized Additive Mixed
Models were used to assess the effect of survey day (seasonality), hour
(diel variation), moon phase, and received levels of noise (measured
from a single pulse during each ten-minute sampled period) on singer
number. The number of singers significantly decreased with increasing
received level of noise, suggesting that humpback whale
[[Page 49684]]
communication was disrupted to some extent by the survey activity.
Castellote et al. (2012) reported acoustic and behavioral changes
by fin whales in response to shipping and air gun noise. Acoustic
features of fin whale song notes recorded in the Mediterranean Sea and
northeast Atlantic Ocean were compared for areas with different
shipping noise levels and traffic intensities and during an air gun
survey. During the first 72 hours of the survey, a steady decrease in
song received levels and bearings to singers indicated that whales
moved away from the acoustic source and out of a Navy study area. This
displacement persisted for a time period well beyond the 10-day
duration of air gun activity, providing evidence that fin whales may
avoid an area for an extended period in the presence of increased
noise. The authors hypothesize that fin whale acoustic communication is
modified to compensate for increased background noise and that a
sensitization process may play a role in the observed temporary
displacement.
Seismic pulses at average received levels of 131 dB re 1
[micro]Pa\2\-s caused blue whales to increase call production (Di Iorio
and Clark, 2010). In contrast, McDonald et al. (1995) tracked a blue
whale with seafloor seismometers and reported that it stopped
vocalizing and changed its travel direction at a range of 10 km from
the seismic vessel (estimated received level 143 dB re: 1 [micro]Pa
peak-to-peak). Blackwell et al. (2013) found that bowhead whale call
rates dropped significantly at onset of air gun use at sites with a
median distance of 41-45 km from the survey. Blackwell et al. (2015)
expanded this analysis to show that whales actually increased calling
rates as soon as air gun signals were detectable before ultimately
decreasing calling rates at higher received levels (i.e., 10-minute
cumulative sound exposure level (cSEL) of ~127 dB). Overall, these
results suggest that bowhead whales may adjust their vocal output in an
effort to compensate for noise before ceasing vocalization effort and
ultimately deflecting from the acoustic source (Blackwell et al., 2013,
2015). Captive bottlenose dolphins sometimes vocalized after an
exposure to impulse sound from a seismic water gun (Finneran et al.,
2010a). These studies demonstrate that even low levels of noise
received far from the noise source can induce changes in vocalization
and/or behavioral responses.
Avoidance
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors. Richardson et al. (1995) noted that avoidance reactions are
the most obvious manifestations of disturbance in marine mammals.
Avoidance is qualitatively different from the flight response, but also
differs in the magnitude of the response (i.e., directed movement, rate
of travel, etc.). Oftentimes avoidance is temporary, and animals return
to the area once the noise has ceased. Acute avoidance responses have
been observed in captive porpoises and pinnipeds exposed to a number of
different sound sources (Kastelein et al., 2001; Finneran et al., 2003;
Kastelein et al., 2006a; Kastelein et al., 2006b; Kastelein et al.,
2015d; Kastelein et al., 2015e; Kastelein et al., 2018b). Short-term
avoidance of seismic surveys, low frequency emissions, and acoustic
deterrents have also been noted in wild populations of odontocetes
(Bowles et al., 1994; Goold, 1996; 1998; Stone et al., 2000; Morton and
Symonds, 2002; Hiley et al., 2021) and to some extent in mysticetes
(Gailey et al., 2007). Longer-term displacement is possible, however,
which may lead to changes in abundance or distribution patterns of the
affected species in the affected region if habituation to the presence
of the sound does not occur (e.g., Blackwell et al., 2004; Bejder et
al., 2006; Teilmann et al., 2006). Longer term or repetitive/chronic
displacement for some dolphin groups and for manatees has been
suggested to be due to the presence of chronic vessel noise (Haviland-
Howell et al., 2007; Miksis-Olds et al., 2007). Gray whales have been
reported deflecting from customary migratory paths in order to avoid
noise from air gun surveys (Malme et al., 1984). Humpback whales showed
avoidance behavior in the presence of an active air gun array during
observational studies and controlled exposure experiments in western
Australia (McCauley et al., 2000a).
As discussed earlier, Forney et al. (2017) detailed the potential
effects of noise on marine mammal populations with high site fidelity,
including displacement and auditory masking, noting that a lack of
observed response does not imply absence of fitness costs and that
apparent tolerance of disturbance may have population-level impacts
that are less obvious and difficult to document. Avoidance of overlap
between disturbing noise and areas and/or times of particular
importance for sensitive species may be critical to avoiding
population-level impacts because (particularly for animals with high
site fidelity) there may be a strong motivation to remain in the area
despite negative impacts. Forney et al. (2017) stated that, for these
animals, remaining in a disturbed area may reflect a lack of
alternatives rather than a lack of effects. The authors discuss several
case studies, including western Pacific gray whales, which are a small
population of mysticetes believed to be adversely affected by oil and
gas development off Sakhalin Island, Russia (Weller et al., 2002;
Reeves et al., 2005). Western gray whales display a high degree of
interannual site fidelity to the area for foraging purposes, and
observations in the area during air gun surveys have shown the
potential for harm caused by displacement from such an important area
(Weller et al., 2006; Johnson et al., 2007). Forney et al. (2017) also
discuss beaked whales, noting that anthropogenic effects in areas where
they are resident could cause severe biological consequences, in part
because displacement may adversely affect foraging rates, reproduction,
or health, while an overriding instinct to remain could lead to more
severe acute effects.
In 1998, the Navy conducted a Low Frequency Sonar Scientific
Research Program (LFS SRP) specifically to study behavioral responses
of several species of marine mammals to exposure to LF sound, including
one phase that focused on the behavior of gray whales to low frequency
sound signals. The objective of this phase of the LFS SRP was to
determine whether migrating gray whales respond more strongly to
received levels, sound gradient, or distance from the source, and to
compare whale avoidance responses to a LF source in the center of the
migration corridor versus in the offshore portion of the migration
corridor. A single source was used to broadcast LFAS sounds at received
levels of 170-178 dB re: 1 [micro]Pa. The Navy reported that the whales
showed some avoidance responses when the source was moored one mile
(1.8 km) offshore, and located within the migration path, but the
whales returned to their migration path when they were a few kilometers
beyond the source. When the source was moored two miles (3.7 km)
offshore, responses were much less, even when the source level was
increased to achieve the same received levels in the middle of the
migration corridor as whales received when the source was located
within the migration corridor (Clark et al., 1999). In addition, the
researchers noted that the offshore whales did not seem to avoid the
louder offshore source.
Also during the LFS SRP, researchers sighted numerous odontocete
and pinniped species in the vicinity of the
[[Page 49685]]
sound exposure tests with LFA sonar. The MF and HF hearing specialists
present in California and Hawaii showed no immediately obvious
responses or changes in sighting rates as a function of source
conditions. Consequently, the researchers concluded that none of these
species had any obvious behavioral reaction to LFA sonar signals at
received levels similar to those that produced only minor short-term
behavioral responses in the baleen whales (i.e., LF hearing
specialists). Thus, for odontocetes, the chances of injury and/or
significant behavioral responses to LFA sonar would be low given the
MF/HF specialists' observed lack of response to LFA sounds during the
LFS SRP and due to the MF/HF frequencies to which these animals are
adapted to hear (Clark and Southall, 2009).
Maybaum (1993) conducted sound playback experiments to assess the
effects of MFAS on humpback whales in Hawaiian waters. Specifically,
she exposed focal pods to sounds of a 3.3-kHz sonar pulse, a sonar
frequency sweep from 3.1 to 3.6 kHz, and a control (blank) tape while
monitoring behavior, movement, and underwater vocalizations. The two
types of sonar signals differed in their effects on the humpback
whales, but both resulted in avoidance behavior. The whales responded
to the pulse by increasing their distance from the sound source and
responded to the frequency sweep by increasing their swimming speeds
and track linearity. In the Caribbean, sperm whales avoided exposure to
mid-frequency submarine sonar pulses, in the range of 1000 Hz to 10,000
Hz (IWC, 2005).
Kvadsheim et al. (2007) conducted a controlled exposure experiment
in which killer whales fitted with D-tags were exposed to mid-frequency
active sonar (Source A: a 1.0 second upsweep 209 dB at 1-2 kHz every 10
seconds for 10 minutes; Source B: with a 1.0 second upsweep 197 dB at
6-7 kHz every 10 seconds for 10 minutes). When exposed to Source A, a
tagged whale and the group it was traveling with did not appear to
avoid the source. When exposed to Source B, the tagged whales along
with other whales that had been carousel feeding, where killer whales
cooperatively herd fish schools into a tight ball towards the surface
and feed on the fish which have been stunned by tailslaps, and
subsurface feeding (Simila, 1997) ceased feeding during the approach of
the sonar and moved rapidly away from the source. When exposed to
Source B, Kvadsheim et al. (2007) reported that a tagged killer whale
seemed to try to avoid further exposure to the sound field by the
following behaviors: immediately swimming away (horizontally) from the
source of the sound; engaging in a series of erratic and frequently
deep dives that seemed to take it below the sound field; or swimming
away while engaged in a series of erratic and frequently deep dives.
Although the sample sizes in this study are too small to support
statistical analysis, the behavioral responses of the killer whales
were consistent with the results of other studies.
Southall et al. (2007) reviewed the available literature on marine
mammal hearing and physiological and behavioral responses to human-made
sound with the goal of proposing exposure criteria for certain effects.
This peer-reviewed compilation of literature is very valuable, though
Southall et al. (2007) note that not all data are equal and some have
poor statistical power, insufficient controls, and/or limited
information on received levels, background noise, and other potentially
important contextual variables. Such data were reviewed and sometimes
used for qualitative illustration, but no quantitative criteria were
recommended for behavioral responses. All of the studies considered,
however, contain an estimate of the received sound level when the
animal exhibited the indicated response.
In the Southall et al. (2007) publication, for the purposes of
analyzing responses of marine mammals to anthropogenic sound and
developing criteria, the authors differentiate between single pulse
sounds, multiple pulse sounds, and non-pulse sounds. MFAS/HFAS are
considered non-pulse sounds. Southall et al. (2007) summarize the
studies associated with low-frequency, mid-frequency, and high-
frequency cetacean and pinniped responses to non-pulse sounds, based
strictly on received level, in Appendix C of their article (referenced
and summarized in the following paragraphs).
The studies that address responses of low-frequency cetaceans to
non-pulse sounds include data gathered in the field and related to
several types of sound sources (of varying similarity to active sonar)
including: vessel noise, drilling and machinery playback, low-frequency
M-sequences (sine wave with multiple phase reversals) playback,
tactical low-frequency active sonar playback, drill ships, ATOC source,
and non-pulse playbacks. These studies generally indicate no (or very
limited) responses to received levels in the 90 to 120 dB re: 1
[micro]Pa range and an increasing likelihood of avoidance and other
behavioral effects in the 120 to 160 dB re: 1 [micro]Pa range. As
mentioned earlier, though, contextual variables play a very important
role in the reported responses and the severity of effects are not
linear when compared to received level. Also, few of the laboratory or
field datasets had common conditions, behavioral contexts, or sound
sources, so it is not surprising that responses differ.
The studies that address responses of mid-frequency cetaceans to
non-pulse sounds include data gathered both in the field and the
laboratory and related to several different sound sources (of varying
similarity to active sonar) including: pingers, drilling playbacks,
ship and ice-breaking noise, vessel noise, Acoustic Harassment Devices
(AHDs), Acoustic Deterrent Devices (ADDs), MFAS, and non-pulse bands
and tones. Southall et al. (2007) were unable to come to a clear
conclusion regarding the results of these studies. In some cases,
animals in the field showed significant responses to received levels
between 90 and 120 dB re: 1 [micro]Pa, while in other cases these
responses were not seen in the 120 to 150 dB re: 1 [micro]Pa range. The
disparity in results was likely due to contextual variation and the
differences between the results in the field and laboratory data
(animals typically responded at lower levels in the field).
The studies that address responses of high-frequency cetaceans to
non-pulse sounds include data gathered both in the field and the
laboratory and related to several different sound sources (of varying
similarity to active sonar) including: pingers, AHDs, and various
laboratory non-pulse sounds. All of these data were collected from
harbor porpoises. Southall et al. (2007) concluded that the existing
data indicate that harbor porpoises are likely sensitive to a wide
range of anthropogenic sounds at low received levels (~90 to 120 dB re:
1 [micro]Pa), at least for initial exposures. All recorded exposures
above 140 dB re: 1 [micro]Pa induced profound and sustained avoidance
behavior in wild harbor porpoises (Southall et al., 2007). Rapid
habituation was noted in some but not all studies. There are no data to
indicate whether other high frequency cetaceans are as sensitive to
anthropogenic sound as harbor porpoises.
The studies that address the responses of pinnipeds in water to
non-impulsive sounds include data gathered both in the field and the
laboratory and related to several different sound sources including:
AHDs, ATOC, various non-pulse sounds used in underwater data
communication, underwater drilling, and construction noise. Few studies
existed with enough information to
[[Page 49686]]
include them in the analysis. The limited data suggested that exposures
to non-pulse sounds between 90 and 140 dB re: 1 [micro]Pa generally do
not result in strong behavioral responses in pinnipeds in water, but no
data exist at higher received levels.
In 2007, the first in a series of behavioral response studies (BRS)
on deep diving odontocetes conducted by NMFS, Navy, and other
scientists showed one Blainville's beaked whale responding to an MFAS
playback. Tyack et al. (2011) indicates that the playback began when
the tagged beaked whale was vocalizing at depth (at the deepest part of
a typical feeding dive), following a previous control with no sound
exposure. The whale appeared to stop clicking significantly earlier
than usual, when exposed to MF signals in the 130-140 dB (rms) received
level range. After a few more minutes of the playback, when the
received level reached a maximum of 140-150 dB, the whale ascended on
the slow side of normal ascent rates with a longer than normal ascent,
at which point the exposure was terminated. The results are from a
single experiment and a greater sample size is needed before robust and
definitive conclusions can be drawn. Tyack et al. (2011) also indicates
that Blainville's beaked whales appear to be sensitive to noise at
levels well below expected TTS (~160 dB re: 1[micro] Pa). This
sensitivity was manifested by an adaptive movement away from a sound
source. This response was observed irrespective of whether the signal
transmitted was within the band width of MFAS, which suggests that
beaked whales may not respond to the specific sound signatures.
Instead, they may be sensitive to any pulsed sound from a point source
in this frequency range of the MFAS transmission. The response to such
stimuli appears to involve the beaked whale increasing the distance
between it and the sound source. Overall the results from the 2007-2008
study showed a change in diving behavior of the Blainville's beaked
whale to playback of MFAS and predator sounds (Boyd et al., 2008;
Southall et al., 2009; Tyack et al., 2011).
Stimpert et al. (2014) tagged a Baird's beaked whale, which was
subsequently exposed to simulated MFAS. Received levels of sonar on the
tag increased to a maximum of 138 dB re: 1[mu]Pa, which occurred during
the first exposure dive. Some sonar received levels could not be
measured due to flow noise and surface noise on the tag.
Reaction to mid-frequency sounds included premature cessation of
clicking and termination of a foraging dive, and a slower ascent rate
to the surface. Results from a similar behavioral response study in
southern California waters were presented for the 2010-2011 field
season (Southall et al., 2011; DeRuiter et al., 2013b). DeRuiter et al.
(2013b) presented results from two Cuvier's beaked whales that were
tagged and exposed to simulated MFAS during the 2010 and 2011 field
seasons of the southern California behavioral response study. The 2011
whale was also incidentally exposed to MFAS from a distant naval
exercise. Received levels from the MFAS signals from the controlled and
incidental exposures were calculated as 84-144 and 78-106 dB re: 1
[micro]Pa rms, respectively. Both whales showed responses to the
controlled exposures, ranging from initial orientation changes to
avoidance responses characterized by energetic fluking and swimming
away from the source. However, the authors did not detect similar
responses to incidental exposure to distant naval sonar exercises at
comparable received levels, indicating that context of the exposures
(e.g., source proximity, controlled source ramp-up) may have been a
significant factor. Specifically, this result suggests that caution is
needed when using marine mammal response data collected from smaller,
nearer sound sources to predict at what received levels animals may
respond to larger sound sources that are significantly farther away--as
the distance of the source appears to be an important contextual
variable and animals may be less responsive to sources at notably
greater distances. Cuvier's beaked whale responses suggested particular
sensitivity to sound exposure as consistent with results for
Blainville's beaked whale. Similarly, beaked whales exposed to sonar
during British training exercises stopped foraging (DSTL, 2007), and
preliminary results of controlled playback of sonar may indicate
feeding/foraging disruption of killer whales and sperm whales (Miller
et al., 2011).
In the 2007-2008 Bahamas study, playback sounds of a potential
predator--a killer whale--resulted in a similar but more pronounced
reaction, which included longer inter-dive intervals and a sustained
straight-line departure of more than 20 km from the area (Boyd et al.,
2008; Southall et al., 2009; Tyack et al., 2011). The authors noted,
however, that the magnified reaction to the predator sounds could
represent a cumulative effect of exposure to the two sound types since
killer whale playback began approximately 2 hours after MF source
playback. Pilot whales and killer whales off Norway also exhibited
horizontal avoidance of a transducer with outputs in the mid-frequency
range (signals in the 1-2 kHz and 6-7 kHz ranges) (Miller et al.,
2011). Additionally, separation of a calf from its group during
exposure to MFAS playback was observed on one occasion (Miller et al.,
2011, 2012). Miller et al. (2012) noted that this single observed
mother-calf separation was unusual for several reasons, including the
fact that the experiment was conducted in an unusually narrow fjord
roughly one km wide and that the sonar exposure was started unusually
close to the pod including the calf. Both of these factors could have
contributed to calf separation. In contrast, preliminary analyses
suggest that none of the pilot whales or false killer whales in the
Bahamas showed an avoidance response to controlled exposure playbacks
(Southall et al., 2009).
In the 2010 BRS study, researchers again used controlled exposure
experiments to carefully measure behavioral responses of individual
animals to sound exposures of MFAS and pseudo-random noise. For each
sound type, some exposures were conducted when animals were in a
surface feeding (approximately 164 ft (50 m) or less) and/or
socializing behavioral state and others while animals were in a deep
feeding (greater than 164 ft (50 m)) and/or traveling mode. The
researchers conducted the largest number of controlled exposure
experiments on blue whales (n=19) and of these, 11 controlled exposure
experiments involved exposure to the MFAS sound type. For the majority
of controlled exposure experiment transmissions of either sound type,
they noted few obvious behavioral responses detected either by the
visual observers or on initial inspection of the tag data. The
researchers observed that throughout the controlled exposure experiment
transmissions, up to the highest received sound level (absolute RMS
value approximately 160 dB re: 1 [mu]Pa with signal-to-noise ratio
values over 60 dB), two blue whales continued surface feeding behavior
and remained at a range of around 3,820 ft (1,000 m) from the sound
source (Southall et al., 2011). In contrast, another blue whale (later
in the day and greater than 11.5 mi (18.5 km; 10 nmi) from the first
controlled exposure experiment location) exposed to the same stimulus
(MFA) while engaged in a deep feeding/travel state exhibited a
different response. In that case, the blue whale responded almost
immediately following the start of sound transmissions when received
sounds
[[Page 49687]]
were just above ambient background levels (Southall et al., 2011). The
authors note that this kind of temporary avoidance behavior was not
evident in any of the nine controlled exposure experiments involving
blue whales engaged in surface feeding or social behaviors, but was
observed in three of the ten controlled exposure experiments for blue
whales in deep feeding/travel behavioral modes (one involving MFA
sonar; two involving pseudo-random noise) (Southall et al., 2011). The
results of this study, as well as the results of the DeRuiter et al.
(2013b) study of Cuvier's beaked whales discussed above, further
illustrate the importance of behavioral context in understanding and
predicting behavioral responses.
Through analysis of the behavioral response studies, a preliminary
overarching effect of greater sensitivity to all anthropogenic
exposures was seen in beaked whales compared to the other odontocetes
studied (Southall et al., 2009). Therefore, recent studies have focused
specifically on beaked whale responses to active sonar transmissions or
controlled exposure playback of simulated sonar on various military
ranges (Defence Science and Technology Laboratory, 2007; Claridge and
Durban, 2009; Moretti et al., 2009; McCarthy et al., 2011; Miller et
al., 2012; Southall et al., 2011, 2012a, 2012b, 2013, 2014; Tyack et
al., 2011). In the Bahamas, Blainville's beaked whales located on the
instrumented range will move off-range during sonar use and return only
after the sonar transmissions have stopped, sometimes taking several
days to do so (Claridge and Durban 2009; Moretti et al., 2009; McCarthy
et al., 2011; Tyack et al., 2011). Moretti et al. (2014) used
recordings from seafloor-mounted hydrophones at the Atlantic Undersea
Test and Evaluation Center (AUTEC) to analyze the probability of
Blainsville's beaked whale dives before, during, and after Navy sonar
exercises.
Southall et al. (2016) indicates that results from Tyack et al.
(2011), Miller et al. (2015), Stimpert et al. (2014), and DeRuiter et
al. (2013b) beaked whale studies demonstrate clear, strong, and
pronounced but varied behavioral changes including avoidance with
associated energetic swimming and cessation of individual foraging
dives at quite low received levels (~100 to 135 dB re: 1 [mu]Pa) for
exposures to simulated or active MF military sonars (1-8 kHz) with
sound sources approximately 2-5 km away. Similar responses by beaked
whales to sonar have been documented by Stimpert et al. (2014), Falcone
et al. (2017), DiMarzio et al. (2018), and Joyce et al. (2019). Jones-
Todd et al. (2021) developed a discrete-space, continuous-time analysis
to estimate animal occurrence and unique movement probability into and
out of an area over time, in response to sonar. They argue that
existing models in the field are inappropriate for estimating a whale's
exposure to sonar longitudinally and across multiple exercises; most
models treat each day independently and don't consider repeated
exposures over longer periods. This model also allows for individual
variation in movement data. Using seven tagged Blainville's beaked
whales' telemetry data, the model showed transition rates across an
area's borders changing in response to sonar exposure, reflecting an
avoidance response that lasted approximately 3 days after the end of
the exposure. However, there are a number of variables influencing
response or non-response including source distance (close vs. far),
received sound levels, and other contextual variables such as other
sound sources (e.g., vessels, etc.) (Manzano-Roth et al., 2016; Falcone
et al., 2017; Harris et al., 2018). Wensveen et al. (2019) found
northern bottlenose whales to avoid sonar out to distances of 28 km,
but these distances are well in line with those observed on Navy ranges
(Manzano-Roth et al., 2016; Joyce et al., 2019) where the animals
return once the sonar has ceased. When exposed to especially long
durations of naval sonar (up to 13 consecutive hours, repeatedly over 8
days), Cuvier's beaked whale detection rates remained low even 7 days
after the exercise. In addition, a Mesoplodont beaked whale species was
entirely displaced from the area during and at least 7 days after the
sonar activity (Stanistreet et al., 2022). Furthermore, beaked whales
have also shown response to other non-sonar anthropogenic sounds such
as commercial shipping and echosounders (Soto et al., 2006; Pirotta et
al., 2012; Cholewiak et al., 2017). Pirotta et al. (2012) documented
broadband ship noise causing a significant change in beaked whale
behavior up to at least 5.2 km away from the vessel. Even though beaked
whales appear to be sensitive to anthropogenic sounds, the level of
response at the population level does not appear to be significant
based on over a decade of research at two heavily used Navy training
areas in the Pacific (Falcone et al., 2012; Schorr et al., 2014;
DiMarzio et al., 2018; Schorr et al., 2019). With the exception of
seasonal patterns, DiMarzio et al. (2018) did not detect any changes in
annual Cuvier's beaked whale abundance estimates in Southern California
derived from passive acoustic echolocation detections over 9 years
(2010-2018). Similar results for Blainville's beaked whales abundance
estimates over several years was documented in Hawaii (Henderson et
al., 2016; DiMarzio et al., 2018). Visually, there have been documented
repeated sightings in southern California of the same individual
Cuvier's beaked whales over 10 years, sightings of mother-calf pairs,
and sightings of the same mothers with their second calf (Falcone et
al., 2012; Schorr et al., 2014; Schorr et al., 2019; Schorr,
unpublished data).
Baleen whales have shown a variety of responses to impulse sound
sources, including avoidance, reduced surface intervals, altered
swimming behavior, and changes in vocalization rates (Richardson et
al., 1995; Gordon et al., 2003; Southall, 2007). While most bowhead
whales did not show active avoidance until within 8 km of seismic
vessels (Richardson et al., 1995), some whales avoided vessels by more
than 20 km at received levels as low as 120 dB re: 1 [micro]Pa rms.
Additionally, Malme et al. (1988) observed clear changes in diving and
respiration patterns in bowheads at ranges up to 73 km from seismic
vessels, with received levels as low as 125 dB re: 1 [micro]Pa.
Gray whales migrating along the United States West Coast showed
avoidance responses to seismic vessels by 10 percent of animals at 164
dB re: 1 [micro]Pa, and by 90 percent of animals at 190 dB re: 1
[micro]Pa, with similar results for whales in the Bering Sea (Malme,
1986; 1988). In contrast, noise from seismic surveys was not found to
impact feeding behavior or exhalation rates while resting or diving in
western gray whales off the coast of Russia (Yazvenko et al., 2007;
Gailey et al., 2007).
Humpback whales showed avoidance behavior at ranges of 5-8 km from
a seismic array during observational studies and controlled exposure
experiments in western Australia (McCauley, 1998; Todd et al., 1996).
Todd et al. (1996) found no clear short-term behavioral responses by
foraging humpbacks to explosions associated with construction
operations in Newfoundland, but did see a trend of increased rates of
net entanglement and a shift to a higher incidence of net entanglement
closer to the noise source.
The strongest baleen whale response in any behavioral response
study was observed in a minke whale in the 3S2 study, which responded
at 146 dB re: 1 [micro]Pa by strongly avoiding the sound source
(Kvadsheim et al., 2017; Sivle et al., 2015). Although the minke whale
increased its swim speed, directional movement, and respiration rate,
none of these were greater than rates observed in
[[Page 49688]]
baseline behavior, and its dive behavior remained similar to baseline
dives. A minke whale tagged in the Southern California behavioral
response study also responded by increasing its directional movement,
but maintained its speed and dive patterns, and so did not demonstrate
as strong of a response (Kvadsheim et al., 2017). In addition, the 3S2
minke whale demonstrated some of the same avoidance behavior during the
controlled ship approach with no sonar, indicating at least some of the
response was to the vessel (Kvadsheim et al., 2017). Martin et al.
(2015) found that the density of calling minke whales was reduced
during periods of Navy training involving sonar relative to the periods
before training, and increased again in the days after training was
completed. The responses of individual whales could not be assessed, so
in this case it is unknown whether the decrease in calling animals
indicated that the animals left the range, or simply ceased calling.
Similarly, minke whale detections made using Marine Acoustic Recording
Instruments off Jacksonville, FL, were reduced or ceased altogether
during periods of sonar use (Simeone et al., 2015; U.S. Department of
the Navy, 2013b), especially with an increased ping rate (Charif et
al., 2015). Harris et al. (2019b) utilized acoustically generated minke
whale tracks at the U.S. Navy's Pacific Missile Range Facility to
statistically demonstrate changes in the spatial distribution of minke
whale acoustic presence before, during, and after surface ship mid-
frequency active sonar training. The spatial distribution of
probability of acoustic presence was different in the ``During'' phase
compared to the ``Before'' phase, and the probability of presence at
the center of ship activity for the ``During'' phase was close to zero
for both years. The ``After'' phases for both years retained lower
probabilities of presence, suggesting the return to baseline conditions
may take more than 5 days. While the results show a clear spatial
redistribution of calling minke whales during surface ship mid-
frequency active sonar training, a limitation of passive acoustic
monitoring is that one cannot conclude if the whales moved away, went
silent, or a combination of the two.
Orientation
A shift in an animal's resting state or an attentional change via
an orienting response represent behaviors that would be considered mild
disruptions if occurring alone. As previously mentioned, the responses
may co-occur with other behaviors; for instance, an animal may
initially orient toward a sound source, and then move away from it.
Thus, any orienting response should be considered in context of other
reactions that may occur.
Continued Pre-Disturbance Behavior and Habituation
Under some circumstances, some of the individual marine mammals
that are exposed to active sonar transmissions will continue their
normal behavioral activities. In other circumstances, individual
animals will respond to sonar transmissions at lower received levels
and move to avoid additional exposure or exposures at higher received
levels (Richardson et al., 1995).
It is difficult to distinguish between animals that continue their
pre-disturbance behavior without stress responses, animals that
continue their behavior but experience stress responses (that is,
animals that cope with disturbance), and animals that habituate to
disturbance (that is, they may have experienced low-level stress
responses initially, but those responses abated over time). Watkins
(1986) reviewed data on the behavioral reactions of fin, humpback,
right, and minke whales that were exposed to continuous, broadband low-
frequency shipping and industrial noise in Cape Cod Bay. He concluded
that underwater sound was the primary cause of behavioral reactions in
these species of whales and that the whales responded behaviorally to
acoustic stimuli within their respective hearing ranges. Watkins also
noted that whales showed the strongest behavioral reactions to sounds
in the 15 Hz to 28 kHz range, although negative reactions (avoidance,
interruptions in vocalizations, etc.) were generally associated with
sounds that were either unexpected, too loud, suddenly louder or
different, or perceived as being associated with a potential threat
(such as an approaching ship on a collision course). In particular,
whales seemed to react negatively when they were within 100 m of the
source or when received levels increased suddenly in excess of 12 dB
relative to ambient sounds. At other times, the whales ignored the
source of the signal and all four species habituated to these sounds.
Nevertheless, Watkins concluded that whales ignored most sounds in the
background of ambient noise, including sounds from distant human
activities even though these sounds may have had considerable energies
at frequencies well within the whales' range of hearing. Further, he
noted that of the whales observed, fin whales were the most sensitive
of the four species, followed by humpback whales; right whales were the
least likely to be disturbed and generally did not react to low-
amplitude engine noise. By the end of his period of study, Watkins
(1986) concluded that fin and humpback whales had generally habituated
to the continuous and broad-band noise of Cape Cod Bay while right
whales did not appear to change their response. As mentioned above,
animals that habituate to a particular disturbance may have experienced
low-level stress responses initially, but those responses abated over
time. In most cases, this likely means a lessened immediate potential
effect from a disturbance. However, there is cause for concern where
the habituation occurs in a potentially more harmful situation. For
example, animals may become more vulnerable to vessel strikes once they
habituate to vessel traffic (Swingle et al., 1993; Wiley et al., 1995).
Aicken et al. (2005) monitored the behavioral responses of marine
mammals to a new low-frequency active sonar system used by the British
Navy (which would be considered mid-frequency active sonar under this
rule as it operates at frequencies greater than 1,000 Hz). During those
trials, fin whales, sperm whales, Sowerby's beaked whales, long-finned
pilot whales, Atlantic white-sided dolphins, and common bottlenose
dolphins were observed and their vocalizations were recorded. These
monitoring studies detected no evidence of behavioral responses that
the investigators could attribute to exposure to the low-frequency
active sonar during these trials.
Explosive Sources
Underwater explosive detonations send a shock wave and sound energy
through the water and can release gaseous by-products, create an
oscillating bubble, or cause a plume of water to shoot up from the
water surface. The shock wave and accompanying noise are of most
concern to marine animals. Depending on the intensity of the shock wave
and size, location, and depth of the animal, an animal can be injured,
killed, suffer non-lethal physical effects, experience hearing related
effects with or without behavioral responses, or exhibit temporary
behavioral responses or tolerance from hearing the blast sound.
Generally, exposures to higher levels of impulse and pressure levels
would result in greater impacts to an individual animal.
Injuries resulting from a shock wave take place at boundaries
between tissues of different densities. Different velocities are
imparted to tissues of
[[Page 49689]]
different densities, and this can lead to their physical disruption.
Blast effects are greatest at the gas-liquid interface (Landsberg,
2000). Gas-containing organs, particularly the lungs and
gastrointestinal tract, are especially susceptible (Goertner, 1982;
Hill, 1978; Yelverton et al., 1973). Intestinal walls can bruise or
rupture, with subsequent hemorrhage and escape of gut contents into the
body cavity. Less severe gastrointestinal tract injuries include
contusions, petechiae (small red or purple spots caused by bleeding in
the skin), and slight hemorrhaging (Yelverton et al., 1973).
Because the ears are the most sensitive to pressure, they are the
organs most sensitive to injury (Ketten, 2000). Sound-related damage
associated with sound energy from detonations can be theoretically
distinct from injury from the shock wave, particularly farther from the
explosion. If a noise is audible to an animal, it has the potential to
damage the animal's hearing by causing decreased sensitivity (Ketten,
1995). Lethal impacts are those that result in immediate death or
serious debilitation in or near an intense source and are not,
technically, pure acoustic trauma (Ketten, 1995). Sublethal impacts
include hearing loss, which is caused by exposures to perceptible
sounds. Severe damage (from the shock wave) to the ears includes
tympanic membrane rupture, fracture of the ossicles, damage to the
cochlea, hemorrhage, and cerebrospinal fluid leakage into the middle
ear. Moderate injury implies partial hearing loss due to tympanic
membrane rupture and blood in the middle ear. Permanent hearing loss
also can occur when the hair cells are damaged by one very loud event,
as well as by prolonged exposure to a loud noise or chronic exposure to
noise (see the Hearing Loss--Threshold Shift section). The level of
impact from blasts depends on both an animal's location and, at outer
zones, on its sensitivity to the residual noise (Ketten, 1995).
Further Potential Effects of Behavioral Disturbance on Marine Mammal
Fitness
The different ways that marine mammals respond to sound are
sometimes indicators of the ultimate effect that exposure to a given
stimulus will have on the well-being (survival, reproduction, etc.) of
an animal. There are few quantitative marine mammal data relating the
exposure of marine mammals to sound to effects on reproduction or
survival, though data exists for terrestrial species to which we can
draw comparisons for marine mammals. Several authors have reported that
disturbance stimuli may cause animals to abandon nesting and foraging
sites (Sutherland and Crockford, 1993); may cause animals to increase
their activity levels and suffer premature deaths or reduced
reproductive success when their energy expenditures exceed their energy
budgets (Daan et al., 1996; Feare, 1976; Mullner et al., 2004); or may
cause animals to experience higher predation rates when they adopt
risk-prone foraging or migratory strategies (Frid and Dill, 2002). Each
of these studies addressed the consequences of animals shifting from
one behavioral state (e.g., resting or foraging) to another behavioral
state (e.g., avoidance or escape behavior) because of human disturbance
or disturbance stimuli.
One consequence of behavioral avoidance results in the altered
energetic expenditure of marine mammals because energy is required to
move and avoid surface vessels or the sound field associated with
active sonar (Frid and Dill, 2002). Most animals can avoid that
energetic cost by swimming away at slow speeds or speeds that minimize
the cost of transport (Miksis-Olds, 2006), as has been demonstrated in
Florida manatees (Miksis-Olds, 2006).
Those energetic costs increase, however, when animals shift from a
resting state, which is designed to conserve an animal's energy, to an
active state that consumes energy the animal would have conserved had
it not been disturbed. Marine mammals that have been disturbed by
anthropogenic noise and vessel approaches are commonly reported to
shift from resting to active behavioral states, which would imply that
they incur an energy cost.
Morete et al. (2007) reported that undisturbed humpback whale cows
that were accompanied by their calves were frequently observed resting
while their calves circled them (milling). When vessels approached, the
amount of time cows and calves spent resting and milling, respectively,
declined significantly. These results are similar to those reported by
Scheidat et al. (2004) for the humpback whales they observed off the
coast of Ecuador.
Constantine and Brunton (2001) reported that bottlenose dolphins in
the Bay of Islands, New Zealand, engaged in resting behavior just 5
percent of the time when vessels were within 300 m, compared with 83
percent of the time when vessels were not present. However, Heenehan et
al. (2016) report that results of a study of the response of Hawaiian
spinner dolphins to human disturbance suggest that the key factor is
not the sheer presence or magnitude of human activities, but rather the
directed interactions and dolphin-focused activities that elicit
responses from dolphins at rest. This information again illustrates the
importance of context in regard to whether an animal will respond to a
stimulus. Miksis-Olds (2006) and Miksis-Olds et al. (2005) reported
that Florida manatees in Sarasota Bay, Florida, reduced the amount of
time they spent milling and increased the amount of time they spent
feeding when background noise levels increased. Although the acute
costs of these changes in behavior are not likely to exceed an animal's
ability to compensate, the chronic costs of these behavioral shifts are
uncertain.
Attention is the cognitive process of selectively concentrating on
one aspect of an animal's environment while ignoring other things
(Posner, 1994). Because animals (including humans) have limited
cognitive resources, there is a limit to how much sensory information
they can process at any time. The phenomenon called ``attentional
capture'' occurs when a stimulus (usually a stimulus that an animal is
not concentrating on or attending to) ``captures'' an animal's
attention. This shift in attention can occur consciously or
subconsciously (for example, when an animal hears sounds that it
associates with the approach of a predator) and the shift in attention
can be sudden (Dukas, 2002; van Rij, 2007). Once a stimulus has
captured an animal's attention, the animal can respond by ignoring the
stimulus, assuming a ``watch and wait'' posture, or treat the stimulus
as a disturbance and respond accordingly, which includes scanning for
the source of the stimulus or ``vigilance'' (Cowlishaw et al., 2004).
Vigilance is normally an adaptive behavior that helps animals
determine the presence or absence of predators, assess their distance
from conspecifics, or to attend cues from prey (Bednekoff and Lima,
1998; Treves, 2000). Despite those benefits, however, vigilance has a
cost of time; when animals focus their attention on specific
environmental cues, they are not attending to other activities such as
foraging or resting. These effects have generally not been demonstrated
for marine mammals, but studies involving fish and terrestrial animals
have shown that increased vigilance may substantially reduce feeding
rates (Saino, 1994; Beauchamp and Livoreil, 1997; Fritz et al., 2002;
Purser and Radford, 2011). Animals will spend more time being vigilant
(which may translate to less time foraging or resting) when disturbance
stimuli approach an animal more directly, remain at closer distances,
have a greater group size (e.g., multiple surface
[[Page 49690]]
vessels), or co-occur with times that an animal perceives increased
risk (e.g., when they are giving birth or accompanied by a calf). An
example of this concept with terrestrial species involved bighorn sheep
and Dall's sheep, which dedicated more time being vigilant, and less
time resting or foraging, when aircraft made direct approaches over
them (Frid, 2001; Stockwell et al., 1991). Vigilance has also been
documented in pinnipeds at haul-out sites where resting may be
disturbed when seals become alerted and/or flush into the water due to
a variety of disturbances, which may be anthropogenic (noise and/or
visual stimuli) or due to other natural causes such as other pinnipeds
(Richardson et al., 1995; Southall et al., 2007; VanBlaricom, 2010;
Lozano and Hente, 2014).
Chronic disturbance can cause population declines through reduction
of fitness (e.g., decline in body condition) and subsequent reduction
in reproductive success, survival, or both (e.g., Harrington and
Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). For example,
Madsen (1994) reported that pink-footed geese (Anser brachyrhynchus) in
undisturbed habitat gained body mass and had about a 46 percent
reproductive success rate compared with geese in disturbed habitat
(being consistently scared off the fields on which they were foraging)
which did not gain mass and had a 17 percent reproductive success rate.
Similar reductions in reproductive success have been reported for mule
deer (Odocoileus hemionus) disturbed by all-terrain vehicles (Yarmoloy
et al., 1988), caribou (Rangifer tarandus caribou) disturbed by seismic
exploration blasts (Bradshaw et al., 1998), and caribou disturbed by
low-elevation military jet fights (Luick et al., 1996; Harrington and
Veitch, 1992). Similarly, a study of elk (Cervus elaphus) that were
disturbed experimentally by pedestrians concluded that the ratio of
young to mothers was inversely related to disturbance rate (Phillips
and Alldredge, 2000). However, Ridgway et al. (2006) reported that
increased vigilance in bottlenose dolphins exposed to sound over a
five-day period in open-air, open-water enclosures in San Diego Bay did
not cause any sleep deprivation or stress effects such as changes in
cortisol or epinephrine levels.
The primary mechanism by which increased vigilance and disturbance
appear to affect the fitness of individual animals is by disrupting an
animal's time budget and, as a result, reducing the time they might
spend foraging and resting (which increases an animal's activity rate
and energy demand while decreasing their caloric intake/energy). An
example of this concept with terrestrial species involved a study of
grizzly bears (Ursus horribilis) that reported that bears disturbed by
hikers reduced their energy intake by an average of 12 kilocalories/min
(50.2 x 103 kiloJoules/min), and spent energy fleeing or acting
aggressively toward hikers (White et al., 1999). In a separate study,
by integrating different sources of data (e.g., controlled exposure
data, activity monitoring, telemetry tracking, and prey sampling) into
a theoretical model to predict effects from sonar on a blue whale's
daily energy intake, Pirotta et al. (2021) found that tagged blue
whales' activity budgets, lunging rates, and ranging patterns caused
variability in their predicted cost of disturbance.
Lusseau and Bejder (2007) present data from three long-term studies
illustrating the connections between disturbance from whale-watching
boats and population-level effects in cetaceans. In Shark Bay,
Australia, the abundance of bottlenose dolphins was compared within
adjacent control and tourism sites over three consecutive 4.5-year
periods of increasing tourism levels. Between the second and third time
periods, in which tourism doubled, dolphin abundance decreased by 15
percent in the tourism area and did not change significantly in the
control area. In Fiordland, New Zealand, two populations (Milford and
Doubtful Sounds) of bottlenose dolphins with tourism levels that
differed by a factor of seven were observed and significant increases
in travelling time and decreases in resting time were documented for
both. Consistent short-term avoidance strategies were observed in
response to tour boats until a threshold of disturbance was reached
(average 68 minutes between interactions), after which the response
switched to a longer-term habitat displacement strategy. For one
population, tourism only occurred in a part of the home range. However,
tourism occurred throughout the home range of the Doubtful Sound
population and once boat traffic increased beyond the 68-minute
threshold (resulting in abandonment of their home range/preferred
habitat), reproductive success drastically decreased (increased
stillbirths) and abundance decreased significantly (from 67 to 56
individuals in a short period). Last, in a study of northern resident
killer whales off Vancouver Island, exposure to boat traffic was shown
to reduce foraging opportunities and increase traveling time. A simple
bioenergetics model was applied to show that the reduced foraging
opportunities equated to a decreased energy intake of 18 percent, while
the increased traveling incurred an increased energy output of 3-4
percent, which suggests that a management action based on avoiding
interference with foraging might be particularly effective.
On a related note, many animals perform vital functions, such as
feeding, resting, traveling, and socializing, on a diel cycle (24-hour
cycle). Behavioral reactions to noise exposure (such as disruption of
critical life functions, displacement, or avoidance of important
habitat) are more likely to be significant for fitness if they last
more than one diel cycle or recur on subsequent days (Southall et al.,
2007). Consequently, a behavioral response lasting less than one day
and not recurring on subsequent days is not considered particularly
severe unless it could directly affect reproduction or survival
(Southall et al., 2007). It is important to note the difference between
behavioral reactions lasting or recurring over multiple days and
anthropogenic activities lasting or recurring over multiple days. For
example, just because at-sea exercises last for multiple days does not
necessarily mean that individual animals will be either exposed to
those activity-related stressors (i.e., sonar) for multiple days or
further, exposed in a manner that would result in sustained multi-day
substantive behavioral responses.
Stone (2015a) reported data from at-sea observations during 1,196
airgun surveys from 1994 to 2010. When large arrays of airguns
(considered in this study to be 500 in\3\ or more) were firing, lateral
displacement, more localized avoidance, or other changes in behavior
were evident for most odontocetes. However, significant responses to
large arrays were found only for the minke whale and fin whale.
Behavioral responses observed included changes in swimming or surfacing
behavior, with indications that cetaceans remained near the water
surface at these times. Cetaceans were recorded as feeding less often
when large arrays were active. Monitoring of gray whales during an air
gun survey included recording whale movements and respirations pre-,
during-, and post-seismic survey (Gailey et al., 2016). Behavioral
state and water depth were the best ``natural'' predictors of whale
movements and respiration and, after considering natural variation,
none of the response variables were
[[Page 49691]]
significantly associated with survey or vessel sounds.
In order to understand how the effects of activities may or may not
impact species and stocks of marine mammals, it is necessary to
understand not only what the likely disturbances are going to be, but
how those disturbances may affect the reproductive success and
survivorship of individuals, and then how those impacts to individuals
translate to population-level effects. Following on the earlier work of
a committee of the U.S. National Research Council (NRC, 2005), New et
al. (2014), in an effort termed the Potential Consequences of
Disturbance (PCoD), outline an updated conceptual model of the
relationships linking disturbance to changes in behavior and
physiology, health, vital rates, and population dynamics. In this
framework, behavioral and physiological changes can have direct (acute)
effects on vital rates, such as when changes in habitat use or
increased stress levels raise the probability of mother-calf separation
or predation; they can have indirect and long-term (chronic) effects on
vital rates, such as when changes in time/energy budgets or increased
disease susceptibility affect health, which then affects vital rates;
or they can have no effect to vital rates (New et al., 2014). In
addition to outlining this general framework and compiling the relevant
literature that supports it, the authors chose four example species for
which extensive long-term monitoring data exist (southern elephant
seals, North Atlantic right whales, Ziphidae beaked whales, and
bottlenose dolphins) and developed state-space energetic models that
can be used to forecast longer-term, population-level impacts from
behavioral changes. While these are very specific models with very
specific data requirements that cannot yet be applied broadly to
project-specific risk assessments for the majority of species, as well
as requiring significant resources and time to conduct (more than is
typically available to support regulatory compliance for one project),
they are a critical first step towards being able to quantify the
likelihood of a population level effect.
Since New et al. (2014), several publications have described models
developed to examine the long-term effects of environmental or
anthropogenic disturbance of foraging on various life stages of
selected species (sperm whale, Farmer et al. (2018); California sea
lion, McHuron et al. (2018); blue whale, Pirotta et al. (2018a); pilot
whales, Hin et al. (2021); gray whale, McHuron et al., 2021). These
models continue to add to refinement of the approaches to the
population consequences of disturbance (PCOD) framework. Such models
also help identify what data inputs require further investigation.
Pirotta et al. (2018b) provides a review of the PCOD framework with
details on each step of the process and approaches to applying real
data or simulations to achieve each step.
New et al. (2020) found that closed populations of dolphins could
not withstand a higher probability of disturbance, compared to open
populations with no limitation on food. Two bottlenose dolphin
populations in Australia were also modeled over 5 years against a
number of disturbances (Reed et al., 2020), and results indicated that
habitat/noise disturbance had little overall impact on population
abundances in either location, even in the most extreme impact
scenarios modeled. By integrating different sources of data (e.g.,
controlled exposure data, activity monitoring, telemetry tracking, and
prey sampling) into a theoretical model to predict effects from sonar
on a blue whale's daily energy intake, Pirotta et al. (2021) found that
tagged blue whales' activity budgets, lunging rates, and ranging
patterns caused variability in their predicted cost of disturbance.
Dunlop et al. (2021) modeled migrating humpback whale mother-calf pairs
in response to seismic surveys using both a forwards and backwards
approach. While a typical forwards approach can determine if a stressor
would have population-level consequences, authors demonstrated that
working backwards through a PCoD model can be used to assess the
``worst case'' scenario for an interaction of a target species and
stressor. This method may be useful for future management goals when
appropriate data becomes available to fully support the model. Harbor
porpoise movement and foraging were modeled for baseline periods and
then for periods with seismic surveys as well; the models demonstrated
that the seasonality of the seismic activity was an important predictor
of impact (Gallagher et al., 2021). Murray et al. (2021) conducted a
cumulative effects assessment on Northern and Southern resident killer
whales, which involved both a Pathways of Effects conceptual model and
a Population Viability Analysis quantitative simulation model. Authors
found that both populations were highly sensitive to prey abundance,
and were also impacted by the interaction of low prey abundance with
vessel strike, vessel noise, and polychlorinated biphenyls
contaminants. However, more research is needed to validate the
mechanisms of vessel disturbance and environmental containments.
Czapanskiy et al. (2021) modeled energetic costs associated with
behavioral response to mid-frequency active sonar using datasets from
eleven cetaceans' feeding rates, prey characteristics, avoidance
behavior, and metabolic rates. Authors found that the short-term
energetic cost was influenced more by lost foraging opportunities than
increased locomotor effort during avoidance. Additionally, the model
found that mysticetes incurred more energetic cost that odontocetes,
even during mild behavioral responses to sonar.
Stranding and Mortality
The definition for a stranding under title IV of the MMPA is that
(A) a marine mammal is dead and is (i) on a beach or shore of the
United States; or (ii) in waters under the jurisdiction of the United
States (including any navigable waters); or (B) a marine mammal is
alive and is (i) on a beach or shore of the United States and is unable
to return to the water; (ii) on a beach or shore of the United States
and, although able to return to the water, is in need of apparent
medical attention; or (iii) in the waters under the jurisdiction of the
United States (including any navigable waters), but is unable to return
to its natural habitat under its own power or without assistance (see
MMPA section 410(3)). This definition is useful for considering
stranding events even when they occur beyond lands and waters under the
jurisdiction of the United States.
Marine mammal strandings have been linked to a variety of causes,
such as illness from exposure to infectious agents, biotoxins, or
parasites; starvation; unusual oceanographic or weather events; or
anthropogenic causes including fishery interaction, ship strike,
entrainment, entrapment, sound exposure, or combinations of these
stressors sustained concurrently or in series. Historically, the cause
or causes of most strandings have remained unknown (Geraci et al.,
1976; Eaton, 1979; Odell et al., 1980; Best, 1982), but the development
of trained, professional stranding response networks and improved
analyses have led to a greater understanding of marine mammal stranding
causes (Simeone and Moore 2017).
Numerous studies suggest that the physiology, behavior, habitat,
social relationships, age, or condition of cetaceans may cause them to
strand or might predispose them to strand when exposed to another
phenomenon. These
[[Page 49692]]
suggestions are consistent with the conclusions of numerous other
studies that have demonstrated that combinations of dissimilar
stressors commonly combine to kill an animal or dramatically reduce its
fitness, even though one exposure without the other does not produce
the same result (Bernaldo de Quiros et al., 2019; Chroussos, 2000;
Creel, 2005; DeVries et al., 2003; Fair and Becker, 2000; Foley et al.,
2001; Moberg, 2000; Relyea, 2005a, 2005b; Romero, 2004; Sih et al.,
2004).
Historically, stranding reporting and response efforts have been
inconsistent, although significant improvements have occurred over the
last 25 years. Reporting forms for basic (``Level A'') information,
rehabilitation disposition, and human interaction have been
standardized nationally (available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/level-data-collection-marine-mammal-stranding-events). However, data collected beyond basic information
varies by region (and may vary from case to case), and are not
standardized across the United States. Logistical conditions such as
weather, time, location, and decomposition state may also affect the
ability of the stranding network to thoroughly examine a specimen
(Carretta et al., 2016b; Moore et al., 2013). While the investigation
of stranded animals provides insight into the types of threats marine
mammal populations face, full investigations are only possible and
conducted on a small fraction of the total number of strandings that
occur, limiting our understanding of the causes of strandings (Carretta
et al., 2016a). Additionally, and due to the variability in effort and
data collected, the ability to interpret long-term trends in stranded
marine mammals is complicated.
Several mass strandings (strandings that involve two or more
individuals of the same species, excluding a single mother-calf pair)
that have occurred over the past two decades have been associated with
anthropogenic activities that introduced sound into the marine
environment such as naval operations and seismic surveys. An in-depth
discussion of strandings is in the Navy's Technical Report on Marine
Mammal Strandings Associated with U.S. Navy Sonar Activities (U.S. Navy
Marine Mammal Program & Space and Naval Warfare Systems Command Center
Pacific, 2017).
Worldwide, there have been several efforts to identify
relationships between cetacean mass stranding events and military
active sonar (Cox et al., 2006; Hildebrand, 2004; IWC, 2005; Taylor et
al., 2004). For example, based on a review of mass stranding events
around the world consisting of two or more individuals of Cuvier's
beaked whales, records from the International Whaling Commission (IWC)
(2005) show that a quarter (9 of 41) were associated with concurrent
naval patrol, explosion, maneuvers, or MFAS. D'Amico et al. (2009)
reviewed beaked whale stranding data compiled primarily from the
published literature (which provides an incomplete record of stranding
events, as many are not written up for publication), along with
unpublished information from some regions of the world.
Most of the stranding events reviewed by the IWC involved beaked
whales. A mass stranding of Cuvier's beaked whales in the eastern
Mediterranean Sea occurred in 1996 (Frantzis, 1998), and mass stranding
events involving Gervais' beaked whales, Blainville's beaked whales,
and Cuvier's beaked whales occurred off the coast of the Canary Islands
in the late 1980s (Simmonds and Lopez-Jurado, 1991). The stranding
events that occurred in the Canary Islands and Kyparissiakos Gulf in
the late 1990s and the Bahamas in 2000 have been the most intensively
studied mass stranding events and have been associated with naval
maneuvers involving the use of tactical sonar. Other cetacean species
with naval sonar implicated in stranding events include harbor porpoise
(Phocoena phocoena) (Norman et al., 2004; Wright et al., 2013) and
common dolphin (Delphinus delphis) (Jepson and Deaville 2009).
Strandings Associated with Impulsive Sound
Silver Strand
During a Navy training event on March 4, 2011 at the Silver Strand
Training Complex in San Diego, California, three or possibly four
dolphins were killed in an explosion. During an underwater detonation
training event, a pod of 100 to 150 long-beaked common dolphins were
observed moving towards the 700-yd (640.1 m) exclusion zone around the
explosive charge, monitored by personnel in a safety boat and
participants in a dive boat. Approximately 5 minutes remained on a
time-delay fuse connected to a single 8.76 lbs (3.97 kg) explosive
charge (C-4 and detonation cord). Although the dive boat was placed
between the pod and the explosive in an effort to guide the dolphins
away from the area, that effort was unsuccessful and three long-beaked
common dolphins near the explosion died. In addition to the three
dolphins found dead on March 4, the remains of a fourth dolphin were
discovered on March 7, 2011 near Oceanside, California (3 days later
and approximately 68 km north of the detonation), which might also have
been related to this event. Association of the fourth stranding with
the training event is uncertain because dolphins strand on a regular
basis in the San Diego area. Details such as the dolphins' depth and
distance from the explosive at the time of the detonation could not be
estimated from the 250 yd (228.6 m) standoff point of the observers in
the dive boat or the safety boat.
These dolphin mortalities are the only known occurrence of a U.S.
Navy training or testing event involving impulsive energy (underwater
detonation) that caused mortality or injury to a marine mammal. Despite
this being a rare occurrence, NMFS and the Navy reviewed training
requirements, safety procedures, and possible mitigation measures and
implemented changes to reduce the potential for this to occur in the
future--specifically increasing the size of the exclusion zone to
better account for the time-delay fuse and the distance that marine
mammals might travel during the time delay. Discussions of procedures
associated with in-air explosives at or above the water surface during
training are presented in the Proposed Mitigation Measures section.
Kyle of Durness, Scotland
On July 22, 2011 a mass stranding event involving long-finned pilot
whales occurred at Kyle of Durness, Scotland. An investigation by
Brownlow et al. (2015) considered unexploded ordnance detonation
activities at a Ministry of Defense bombing range, conducted by the
Royal Navy prior to and during the strandings, as a plausible
contributing factor in the mass stranding event. While Brownlow et al.
(2015) concluded that the serial detonations of underwater ordnance
were an influential factor in the mass stranding event (along with the
presence of a potentially compromised animal and navigational error in
a topographically complex region), they also suggest that mitigation
measures--which included observations from a zodiac only and by
personnel not experienced in marine mammal observation, among other
deficiencies--were likely insufficient to assess if cetaceans were in
the vicinity of the detonations. The authors also cite information from
the Ministry of Defense indicating ``an extraordinarily high level of
activity'' (i.e., frequency and intensity of underwater explosions) on
the range in the days leading up to the stranding.
[[Page 49693]]
Strandings Associated With Active Sonar
Over the past 21 years, there have been five stranding events
coincident with naval MF active sonar use in which exposure to sonar is
believed to have been a contributing factor: Greece (1996); the Bahamas
(2000); Madeira (2000); Canary Islands (2002); and Spain (2006) (Cox et
al., 2006; Fernandez, 2006; U.S. Navy Marine Mammal Program & Space and
Naval Warfare Systems Command Center Pacific, 2017). These five mass
strandings have resulted in about 40 known cetacean deaths consisting
mostly of beaked whales and with close linkages to mid-frequency active
sonar activity. In these circumstances, exposure to non-impulsive
acoustic energy was considered a potential indirect cause of death of
the marine mammals (Cox et al., 2006). Only one of these stranding
events, the Bahamas (2000), was associated with exercises conducted by
the U.S. Navy. Additionally, in 2004, during the Rim of the Pacific
(RIMPAC) exercises, between 150 and 200 usually pelagic melon-headed
whales occupied the shallow waters of Hanalei Bay, Kauai, Hawaii for
over 28 hours. NMFS determined that MFAS was a plausible, if not
likely, contributing factor in what may have been a confluence of
events that led to the Hanalei Bay stranding. A number of other
stranding events coincident with the operation of MFAS, including the
death of beaked whales or other species (minke whales, dwarf sperm
whales, pilot whales), have been reported; however, the majority have
not been investigated to the degree necessary to determine the cause of
the stranding. Most recently, the Independent Scientific Review Panel
investigating potential contributing factors to a 2008 mass stranding
of melon-headed whales in Antsohihy, Madagascar released its final
report suggesting that the stranding was likely initially triggered by
an industry seismic survey (Southall et al., 2013). This report
suggests that the operation of a commercial high-powered 12 kHz multi-
beam echosounder during an industry seismic survey was a plausible and
likely initial trigger that caused a large group of melon-headed whales
to leave their typical habitat and then ultimately strand as a result
of secondary factors such as malnourishment and dehydration. The report
indicates that the risk of this particular convergence of factors and
ultimate outcome is likely very low, but recommends that the potential
be considered in environmental planning. Because of the association
between tactical mid-frequency active sonar use and a small number of
marine mammal strandings, the Navy and NMFS have been considering and
addressing the potential for strandings in association with Navy
activities for years. In addition to the proposed mitigation measures
intended to more broadly minimize impacts to marine mammals, the Navy
would abide by the Notification and Reporting Plan, which sets out
notification, reporting, and other requirements when dead, injured, or
stranded marine mammals are detected in certain circumstances.
Greece (1996)
Twelve Cuvier's beaked whales stranded atypically (in both time and
space) along a 38.2-km strand of the Kyparissiakos Gulf coast on May 12
and 13, 1996 (Frantzis, 1998). From May 11 through May 15, the North
Atlantic Treaty Organization (NATO) research vessel Alliance was
conducting sonar tests with signals of 600 Hz and 3 kHz and source
levels of 228 and 226 dB re: 1[mu]Pa, respectively (D'Amico and
Verboom, 1998; D'Spain et al., 2006). The timing and location of the
testing encompassed the time and location of the strandings (Frantzis,
1998).
Necropsies of eight of the animals were performed but were limited
to basic external examination and sampling of stomach contents, blood,
and skin. No ears or organs were collected, and no histological samples
were preserved. No significant apparent abnormalities or wounds were
found, however examination of photos of the animals, taken soon after
their death, revealed that the eyes of at least four of the individuals
were bleeding (Frantzis, 2004). Stomach contents contained the flesh of
cephalopods, indicating that feeding had recently taken place
(Frantzis, 1998).
All available information regarding the conditions associated with
this stranding event was compiled, and many potential causes were
examined including major pollution events, prominent tectonic activity,
unusual physical or meteorological events, magnetic anomalies,
epizootics, and conventional military activities (International Council
for the Exploration of the Sea, 2005a). However, none of these
potential causes coincided in time or space with the mass stranding, or
could explain its characteristics (International Council for the
Exploration of the Sea, 2005a). The robust condition of the animals,
plus the recent stomach contents, is inconsistent with pathogenic
causes. In addition, environmental causes can be ruled out as there
were no unusual environmental circumstances or events before or during
this time period and within the general proximity (Frantzis, 2004).
Because of the rarity of this mass stranding of Cuvier's beaked
whales in the Kyparissiakos Gulf (first one in historical records), the
probability for the two events (the military exercises and the
strandings) to coincide in time and location, while being independent
of each other, was thought to be extremely low (Frantzis, 1998).
However, because full necropsies had not been conducted, and no
abnormalities were noted, the cause of the strandings could not be
precisely determined (Cox et al., 2006). A Bioacoustics Panel convened
by NATO concluded that the evidence available did not allow them to
accept or reject sonar exposures as a causal agent in these stranding
events. The analysis of this stranding event provided support for, but
no clear evidence for, the cause-and-effect relationship of tactical
sonar training activities and beaked whale strandings (Cox et al.,
2006).
Bahamas (2000)
NMFS and the Navy prepared a joint report addressing the multi-
species stranding in the Bahamas in 2000, which took place within 24
hours of U.S. Navy ships using MFAS as they passed through the
Northeast and Northwest Providence Channels on March 15-16, 2000. The
ships, which operated both AN/SQS-53C and AN/SQS-56, moved through the
channel while emitting sonar pings approximately every 24 seconds. Of
the 17 cetaceans that stranded over a 36-hour period (Cuvier's beaked
whales, Blainville's beaked whales, minke whales, and a spotted
dolphin), seven animals died on the beach (five Cuvier's beaked whales,
one Blainville's beaked whale, and the spotted dolphin), while the
other 10 were returned to the water alive (though their ultimate fate
is unknown). As discussed in the Bahamas report (DOC/DON, 2001), there
is no likely association between the minke whale and spotted dolphin
strandings and the operation of MFAS.
Necropsies were performed on five of the stranded beaked whales.
All five necropsied beaked whales were in good body condition, showing
no signs of infection, disease, ship strike, blunt trauma, or fishery
related injuries, and three still had food remains in their stomachs.
Auditory structural damage was discovered in four of the whales,
specifically bloody effusions or hemorrhaging around the ears.
Bilateral intracochlear and unilateral temporal region subarachnoid
hemorrhage, with blood clots in the lateral ventricles,
[[Page 49694]]
were found in two of the whales. Three of the whales had small
hemorrhages in their acoustic fats (located along the jaw and in the
melon).
A comprehensive investigation was conducted and all possible causes
of the stranding event were considered, whether they seemed likely at
the outset or not. Based on the way in which the strandings coincided
with ongoing naval activity involving tactical MFAS use, in terms of
both time and geography, the nature of the physiological effects
experienced by the dead animals, and the absence of any other acoustic
sources, the investigation team concluded that MFAS aboard U.S. Navy
ships that were in use during the active sonar exercise in question
were the most plausible source of this acoustic or impulse trauma to
beaked whales. This sound source was active in a complex environment
that included the presence of a surface duct, unusual and steep
bathymetry, a constricted channel with limited egress, intensive use of
multiple, active sonar units over an extended period of time, and the
presence of beaked whales that appear to be sensitive to the
frequencies produced by these active sonars. The investigation team
concluded that the cause of this stranding event was the confluence of
the Navy MFAS and these contributory factors working together, and
further recommended that the Navy avoid operating MFAS in situations
where these five factors would be likely to occur. This report does not
conclude that all five of these factors must be present for a stranding
to occur, nor that beaked whales are the only species that could
potentially be affected by the confluence of the other factors. Based
on this, NMFS believes that the operation of MFAS in situations where
surface ducts exist, or in marine environments defined by steep
bathymetry and/or constricted channels may increase the likelihood of
producing a sound field with the potential to cause cetaceans
(especially beaked whales) to strand, and therefore, suggests the need
for increased vigilance while operating MFAS in these areas, especially
when beaked whales (or potentially other deep divers) are likely
present.
Madeira, Portugal (2000)
From May 10-14, 2000, three Cuvier's beaked whales were found
atypically stranded on two islands in the Madeira archipelago, Portugal
(Cox et al., 2006). A fourth animal was reported floating in the
Madeiran waters by a fisherman but did not come ashore (Woods Hole
Oceanographic Institution, 2005). Joint NATO amphibious training
peacekeeping exercises involving participants from 17 countries and 80
warships, took place in Portugal during May 2-15, 2000.
The bodies of the three stranded whales were examined post mortem
(Woods Hole Oceanographic Institution, 2005), though only one of the
stranded whales was fresh enough (24 hours after stranding) to be
necropsied (Cox et al., 2006). Results from the necropsy revealed
evidence of hemorrhage and congestion in the right lung and both
kidneys (Cox et al., 2006). There was also evidence of intercochlear
and intracranial hemorrhage similar to that which was observed in the
whales that stranded in the Bahamas event (Cox et al., 2006). There
were no signs of blunt trauma, and no major fractures (Woods Hole
Oceanographic Institution, 2005). The cranial sinuses and airways were
found to be clear with little or no fluid deposition, which may
indicate good preservation of tissues (Woods Hole Oceanographic
Institution, 2005).
Several observations on the Madeira stranded beaked whales, such as
the pattern of injury to the auditory system, are the same as those
observed in the Bahamas strandings. Blood in and around the eyes,
kidney lesions, pleural hemorrhages, and congestion in the lungs are
particularly consistent with the pathologies from the whales stranded
in the Bahamas, and are consistent with stress and pressure related
trauma. The similarities in pathology and stranding patterns between
these two events suggest that a similar pressure event may have
precipitated or contributed to the strandings at both sites (Woods Hole
Oceanographic Institution, 2005).
Even though no definitive causal link can be made between the
stranding event and naval exercises, certain conditions may have
existed in the exercise area that, in their aggregate, may have
contributed to the marine mammal strandings (Freitas, 2004): exercises
were conducted in areas of at least 547 fathoms (1,000 m) depth near a
shoreline where there is a rapid change in bathymetry on the order of
547 to 3,281 fathoms (1,000 to 6,000 m) occurring across a relatively
short horizontal distance (Freitas, 2004); multiple ships were
operating around Madeira, though it is not known if MFAS was used, and
the specifics of the sound sources used are unknown (Cox et al., 2006,
Freitas, 2004); and exercises took place in an area surrounded by
landmasses separated by less than 35 nmi (65 km) and at least 10 nmi
(19 km) in length, or in an embayment. Exercises involving multiple
ships employing MFAS near land may produce sound directed towards a
channel or embayment that may cut off the lines of egress for marine
mammals (Freitas, 2004).
Canary Islands, Spain (2002)
The southeastern area within the Canary Islands is well known for
aggregations of beaked whales due to its ocean depths of greater than
547 fathoms (1,000 m) within a few hundred meters of the coastline
(Fernandez et al., 2005). On September 24, 2002, 14 beaked whales were
found stranded on Fuerteventura and Lanzarote Islands in the Canary
Islands (International Council for Exploration of the Sea, 2005a).
Seven whales died, while the remaining seven live whales were returned
to deeper waters (Fernandez et al., 2005). Four beaked whales were
found stranded dead over the next 3 days either on the coast or
floating offshore. These strandings occurred within close proximity of
an international naval exercise that utilized MFAS and involved
numerous surface warships and several submarines. Strandings began
about 4 hours after the onset of MFAS activity (International Council
for Exploration of the Sea, 2005a; Fernandez et al., 2005).
Eight Cuvier's beaked whales, one Blainville's beaked whale, and
one Gervais' beaked whale were necropsied, 6 of them within 12 hours of
stranding (Fernandez et al., 2005). No pathogenic bacteria were
isolated from the carcasses (Jepson et al., 2003). The animals
displayed severe vascular congestion and hemorrhage especially around
the tissues in the jaw, ears, brain, and kidneys, displaying marked
disseminated microvascular hemorrhages associated with widespread fat
emboli (Jepson et al., 2003; International Council for Exploration of
the Sea, 2005a). Several organs contained intravascular bubbles,
although definitive evidence of gas embolism in vivo is difficult to
determine after death (Jepson et al., 2003). The livers of the
necropsied animals were the most consistently affected organ, which
contained macroscopic gas-filled cavities and had variable degrees of
fibrotic encapsulation. In some animals, cavitary lesions had
extensively replaced the normal tissue (Jepson et al., 2003). Stomachs
contained a large amount of fresh and undigested contents, suggesting a
rapid onset of disease and death (Fernandez et al., 2005). Head and
neck lymph nodes were enlarged and congested, and parasites were found
in the kidneys of all animals (Fernandez et al., 2005).
The association of NATO MFAS use close in space and time to the
beaked
[[Page 49695]]
whale strandings, and the similarity between this stranding event and
previous beaked whale mass strandings coincident with sonar use,
suggests that a similar scenario and causative mechanism of stranding
may be shared between the events. Beaked whales stranded in this event
demonstrated brain and auditory system injuries, hemorrhages, and
congestion in multiple organs, similar to the pathological findings of
the Bahamas and Madeira stranding events. In addition, the necropsy
results of the Canary Islands stranding event lead to the hypothesis
that the presence of disseminated and widespread gas bubbles and fat
emboli were indicative of nitrogen bubble formation, similar to what
might be expected in decompression sickness (Jepson et al., 2003;
Fern[aacute]ndez et al., 2005).
Hanalei Bay, Hawaii (2004)
On July 3 and 4, 2004, approximately 150 to 200 melon-headed whales
occupied the shallow waters of Hanalei Bay, Kauai, Hawaii for over 28
hours. Attendees of a canoe blessing observed the animals entering the
Bay in a single wave formation at 7 a.m. on July 3, 2004. The animals
were observed moving back into the shore from the mouth of the Bay at 9
a.m. The usually pelagic animals milled in the shallow bay and were
returned to deeper water with human assistance beginning at 9:30 a.m.
on July 4, 2004, and were out of sight by 10:30 a.m.
Only one animal, a calf, was known to have died following this
event. The animal was noted alive and alone in the Bay on the afternoon
of July 4, 2004, and was found dead in the Bay the morning of July 5,
2004. A full necropsy, magnetic resonance imaging, and computerized
tomography examination were performed on the calf to determine the
manner and cause of death. The combination of imaging, necropsy, and
histological analyses found no evidence of infectious, internal
traumatic, congenital, or toxic factors. Cause of death could not be
definitively determined, but it is likely that maternal separation,
poor nutritional condition, and dehydration contributed to the final
demise of the animal. Although it is not known when the calf was
separated from its mother, the animals' movement into the Bay and
subsequent milling and re-grouping may have contributed to the
separation or lack of nursing, especially if the maternal bond was weak
or this was an inexperienced mother with her first calf.
Environmental factors, abiotic and biotic, were analyzed for any
anomalous occurrences that would have contributed to the animals
entering and remaining in Hanalei Bay. The Bay's bathymetry is similar
to many other sites within the Hawaiian Island chain and dissimilar to
sites that have been associated with mass strandings in other parts of
the United States. The weather conditions appeared to be normal for
that time of year with no fronts or other significant features noted.
There was no evidence of unusual distribution, occurrence of predator
or prey species, or unusual harmful algal blooms, although Mobley et
al. (2007) suggested that the full moon cycle that occurred at that
time may have influenced a run of squid into the Bay. Weather patterns
and bathymetry that have been associated with mass strandings elsewhere
were not found to occur in this instance.
The Hanalei event was spatially and temporally correlated with
RIMPAC. Official sonar training and tracking exercises in the Pacific
Missile Range Facility (PMRF) warning area did not commence until
approximately 8 a.m. on July 3 and were thus ruled out as a possible
trigger for the initial movement into the Bay. However, six naval
surface vessels transiting to the operational area on July 2
intermittently transmitted active sonar (for approximately 9 hours
total from 1:15 p.m. to 12:30 a.m.) as they approached from the south.
The potential for these transmissions to have triggered the whales'
movement into Hanalei Bay was investigated. Analyses with the
information available indicated that animals to the south and east of
Kaua'i could have detected active sonar transmissions on July 2, and
reached Hanalei Bay on or before 7 a.m. on July 3. However, data
limitations regarding the position of the whales prior to their arrival
in the Bay, the magnitude of sonar exposure, behavioral responses of
melon-headed whales to acoustic stimuli, and other possible relevant
factors preclude a conclusive finding regarding the role of sonar in
triggering this event. Propagation modeling suggests that transmissions
from sonar use during the July 3 exercise in the PMRF warning area may
have been detectable at the mouth of the Bay. If the animals responded
negatively to these signals, it may have contributed to their continued
presence in the Bay. The U.S. Navy ceased all active sonar
transmissions during exercises in this range on the afternoon of July
3. Subsequent to the cessation of sonar use, the animals were herded
out of the Bay.
While causation of this stranding event may never be unequivocally
determined, NMFS considers the active sonar transmissions of July 2-3,
2004, a plausible, if not likely, contributing factor in what may have
been a confluence of events. This conclusion is based on the following:
(1) the evidently anomalous nature of the stranding; (2) its close
spatiotemporal correlation with wide-scale, sustained use of sonar
systems previously associated with stranding of deep-diving marine
mammals; (3) the directed movement of two groups of transmitting
vessels toward the southeast and southwest coast of Kauai; (4) the
results of acoustic propagation modeling and an analysis of possible
animal transit times to the Bay; and (5) the absence of any other
compelling causative explanation. The initiation and persistence of
this event may have resulted from an interaction of biological and
physical factors. The biological factors may have included the presence
of an apparently uncommon, deep-diving cetacean species (and possibly
an offshore, non-resident group), social interactions among the animals
before or after they entered the Bay, and/or unknown predator or prey
conditions. The physical factors may have included the presence of
nearby deep water, multiple vessels transiting in a directed manner
while transmitting active sonar over a sustained period, the presence
of surface sound ducting conditions, and/or intermittent and random
human interactions while the animals were in the Bay.
A separate event involving melon-headed whales and rough-toothed
dolphins took place over the same period of time in the Northern
Mariana Islands (Jefferson et al., 2006), which is several thousand
miles from Hawaii. Some 500 to 700 melon-headed whales came into
Sasanhaya Bay on July 4, 2004, near the island of Rota and then left of
their own accord after 5.5 hours; no known active sonar transmissions
occurred in the vicinity of that event. The Rota incident led to
scientific debate regarding what, if any, relationship the event had to
the simultaneous events in Hawaii and whether they might be related by
some common factor (e.g., there was a full moon on July 2, 2004, as
well as during other melon-headed whale strandings and nearshore
aggregations (Brownell et al., 2009; Lignon et al., 2007; Mobley et
al., 2007). Brownell et al. (2009) compared the two incidents, along
with one other stranding incident at Nuka Hiva in French Polynesia and
normal resting behaviors observed at Palmyra Island, in regard to
physical features in the areas, melon-headed whale behavior, and lunar
cycles. Brownell et al., (2009) concluded that the rapid entry of the
whales into Hanalei Bay,
[[Page 49696]]
their movement into very shallow water far from the 100-m contour,
their milling behavior (typical pre-stranding behavior), and their
reluctance to leave the Bay constituted an unusual event that was not
similar to the events that occurred at Rota, which appear to be similar
to observations of melon-headed whales resting normally at Palmyra
Island. Additionally, there was no correlation between lunar cycle and
the types of behaviors observed in the Brownell et al. (2009) examples.
Spain (2006)
The Spanish Cetacean Society reported an atypical mass stranding of
four beaked whales that occurred January 26, 2006, on the southeast
coast of Spain, near Moj[aacute]car (Gulf of Vera) in the Western
Mediterranean Sea. According to the report, two of the whales were
discovered the evening of January 26 and were found to be still alive.
Two other whales were discovered during the day on January 27, but had
already died. The first three animals were located near the town of
Moj[aacute]car and the fourth animal was found dead, a few kilometers
north of the first three animals. From January 25-26, 2006, Standing
NATO Response Force Maritime Group Two (five of seven ships including
one U.S. ship under NATO Operational Control) had conducted active
sonar training against a Spanish submarine within 50 nmi (93 km) of the
stranding site.
Veterinary pathologists necropsied the two male and two female
Cuvier's beaked whales. According to the pathologists, the most likely
primary cause of this type of beaked whale mass stranding event was
anthropogenic acoustic activities, most probably anti-submarine MFAS
used during the military naval exercises. However, no positive acoustic
link was established as a direct cause of the stranding. Even though no
causal link can be made between the stranding event and naval
exercises, certain conditions may have existed in the exercise area
that, in their aggregate, may have contributed to the marine mammal
strandings (Freitas, 2004). Exercises were conducted in areas of at
least 547 fathoms (1,000 m) depth near a shoreline where there is a
rapid change in bathymetry on the order of 547 to 3,281 fathoms (1,000
to 6,000 m) occurring across a relatively short horizontal distance
(Freitas, 2004). Multiple ships (in this instance, five) were operating
MFAS in the same area over extended periods of time (in this case, 20
hours) in close proximity; and exercises took place in an area
surrounded by landmasses, or in an embayment. Exercises involving
multiple ships employing MFAS near land may have produced sound
directed towards a channel or embayment that may have cut off the lines
of egress for the affected marine mammals (Freitas, 2004).
Behaviorally Mediated Responses to MFAS That May Lead to Stranding
Although the confluence of Navy MFAS with the other contributory
factors noted in the 2001 NMFS/Navy joint report was identified as the
cause of the 2000 Bahamas stranding event, the specific mechanisms that
led to that stranding (or the others) are not well understood, and
there is uncertainty regarding the ordering of effects that led to the
stranding. It is unclear whether beaked whales were directly injured by
sound (e.g., acoustically mediated bubble growth, as addressed above)
prior to stranding or whether a behavioral response to sound occurred
that ultimately caused the beaked whales to be injured and strand.
Although causal relationships between beaked whale stranding events
and active sonar remain unknown, several authors have hypothesized that
stranding events involving these species in the Bahamas and Canary
Islands may have been triggered when the whales changed their dive
behavior in a startled response to exposure to active sonar or to
further avoid exposure (Cox et al., 2006; Rommel et al., 2006). These
authors proposed three mechanisms by which the behavioral responses of
beaked whales upon being exposed to active sonar might result in a
stranding event. These include the following: gas bubble formation
caused by excessively fast surfacing; remaining at the surface too long
when tissues are supersaturated with nitrogen; or diving prematurely
when extended time at the surface is necessary to eliminate excess
nitrogen. More specifically, beaked whales that occur in deep waters
that are in close proximity to shallow waters (for example, the
``canyon areas'' that are cited in the Bahamas stranding event; see
D'Spain and D'Amico, 2006), may respond to active sonar by swimming
into shallow waters to avoid further exposures and strand if they were
not able to swim back to deeper waters. Second, beaked whales exposed
to active sonar might alter their dive behavior. Changes in their dive
behavior might cause them to remain at the surface or at depth for
extended periods of time which could lead to hypoxia directly by
increasing their oxygen demands or indirectly by increasing their
energy expenditures (to remain at depth) and increase their oxygen
demands as a result. If beaked whales are at depth when they detect a
ping from an active sonar transmission and change their dive profile,
this could lead to the formation of significant gas bubbles, which
could damage multiple organs or interfere with normal physiological
function (Cox et al., 2006; Rommel et al., 2006; Zimmer and Tyack,
2007). Baird et al. (2005) found that slow ascent rates from deep dives
and long periods of time spent within 50 m of the surface were typical
for both Cuvier's and Blainville's beaked whales, the two species
involved in mass strandings related to naval sonar. These two
behavioral mechanisms may be necessary to purge excessive dissolved
nitrogen concentrated in their tissues during their frequent long dives
(Baird et al., 2005). Baird et al. (2005) further suggests that
abnormally rapid ascents or premature dives in response to high-
intensity sonar could indirectly result in physical harm to the beaked
whales, through the mechanisms described above (gas bubble formation or
non-elimination of excess nitrogen). In a review of the previously
published data on the potential impacts of sonar on beaked whales,
Bernaldo de Quir[oacute]s et al. (2019) suggested that the effect of
mid-frequency active sonar on beaked whales varies among individuals or
populations, and that predisposing conditions such as previous exposure
to sonar and individual health risk factors may contribute to
individual outcomes (such as decompression sickness).
Because many species of marine mammals make repetitive and
prolonged dives to great depths, it has long been assumed that marine
mammals have evolved physiological mechanisms to protect against the
effects of rapid and repeated decompressions. Although several
investigators have identified physiological adaptations that may
protect marine mammals against nitrogen gas supersaturation (alveolar
collapse and elective circulation; Kooyman et al., 1972; Ridgway and
Howard, 1979), Ridgway and Howard (1979) reported that bottlenose
dolphins that were trained to dive repeatedly had muscle tissues that
were substantially supersaturated with nitrogen gas. Houser et al.
(2001b) used these data to model the accumulation of nitrogen gas
within the muscle tissue of other marine mammal species and concluded
that cetaceans that dive deep and have slow ascent or descent speeds
would have tissues that are more supersaturated with nitrogen gas than
other marine mammals. Based on these data, Cox et al. (2006)
hypothesized that a critical dive sequence might make beaked
[[Page 49697]]
whales more prone to stranding in response to acoustic exposures. The
sequence began with (1) very deep (to depths as deep as 2 km) and long
(as long as 90 minutes) foraging dives; (2) relatively slow, controlled
ascents; and (3) a series of ``bounce'' dives between 100 and 400 m in
depth (see also Zimmer and Tyack, 2007). They concluded that acoustic
exposures that disrupted any part of this dive sequence (for example,
causing beaked whales to spend more time at surface without the bounce
dives that are necessary to recover from the deep dive) could produce
excessive levels of nitrogen supersaturation in their tissues, leading
to gas bubble and emboli formation that produces pathologies similar to
decompression sickness.
Zimmer and Tyack (2007) modeled nitrogen tension and bubble growth
in several tissue compartments for several hypothetical dive profiles
and concluded that repetitive shallow dives (defined as a dive where
depth does not exceed the depth of alveolar collapse, approximately 72
m for Cuvier's beaked whale), perhaps as a consequence of an extended
avoidance reaction to sonar sound, could pose a risk for decompression
sickness and that this risk should increase with the duration of the
response. Their models also suggested that unrealistically rapid rates
of ascent from normal dive behaviors are unlikely to result in
supersaturation to the extent that bubble formation would be expected.
Tyack et al. (2006) suggested that emboli observed in animals exposed
to mid-frequency range sonar (Jepson et al., 2003; Fernandez et al.,
2005; Fern[aacute]ndez et al., 2012) could stem from a behavioral
response that involves repeated dives shallower than the depth at which
lung collapse occurs. Given that nitrogen gas accumulation is a passive
process (i.e., nitrogen is metabolically inert), a bottlenose dolphin
was trained to repetitively dive a profile predicted to elevate
nitrogen saturation to the point that nitrogen bubble formation was
predicted to occur. However, inspection of the vascular system of the
dolphin via ultrasound did not demonstrate the formation of
asymptomatic nitrogen gas bubbles (Houser et al., 2007). Baird et al.
(2008), in a beaked whale tagging study off Hawaii, showed that deep
dives are equally common during day or night, but ``bounce dives'' are
typically a daytime behavior, possibly associated with visual predator
avoidance. This may indicate that ``bounce dives'' are associated with
something other than behavioral regulation of dissolved nitrogen
levels, which would be necessary day and night.
If marine mammals respond to a Navy vessel that is transmitting
active sonar in the same way that they might respond to a predator,
their probability of flight responses could increase when they perceive
that Navy vessels are approaching them directly, because a direct
approach may convey detection and intent to capture (Burger and
Gochfeld, 1981, 1990; Cooper, 1997, 1998). Please see the Flight
Response section of this proposed rule for additional discussion.
Despite the many theories involving bubble formation (both as a
direct cause of injury, see Acoustically-Induced Bubble Formation Due
to Sonars and Other Pressure-related Injury section and an indirect
cause of stranding), Southall et al. (2007) summarizes that there is
either scientific disagreement or a lack of information regarding each
of the following important points: (1) received acoustical exposure
conditions for animals involved in stranding events; (2) pathological
interpretation of observed lesions in stranded marine mammals; (3)
acoustic exposure conditions required to induce such physical trauma
directly; (4) whether noise exposure may cause behavioral reactions
(such as atypical diving behavior) that secondarily cause bubble
formation and tissue damage; and (5) the extent the post mortem
artifacts introduced by decomposition before sampling, handling,
freezing, or necropsy procedures affect interpretation of observed
lesions.
Strandings in the GOA Study Area
Stranded marine mammals are reported along the entire western coast
of the United States each year. Marine mammals strand due to natural or
anthropogenic causes; the majority of reported type of occurrences in
marine mammal strandings in the Pacific include fisheries interactions,
entanglement, vessel strike, and predation (Carretta et al., 2019a;
Carretta et al., 2019b; Carretta et al., 2017a; Helker et al., 2019;
Helker et al., 2017; NOAA, 2018, 2019). Stranding events that are
associated with active UMEs in Alaska (inclusive of the GOA Study Area)
were previously discussed in the Description of Marine Mammals and
Their Habitat in the Area of the Specified Activities section.
In 2020, there were 65 confirmed strandings reported in the Gulf of
Alaska (Savage, 2021). Of these strandings, 43 were cetaceans; 20 of
the stranded cetaceans were gray whales, which as discussed in the
Description of Marine Mammals and Their Habitat in the Area of the
Specified Activities section of this proposed rule, are affected by a
UME. Of the 2020 confirmed reports involving human interaction, most
reports indicated an entanglement. Naval sonar has been identified as a
contributing factor in a small number of strandings as discussed above;
however, none of these have occurred in the GOA Study Area.
Potential Effects of Vessel Strike
Vessel collisions with marine mammals, also referred to as vessel
strikes or ship strikes, can result in death or serious injury of the
animal. Wounds resulting from ship strike may include massive trauma,
hemorrhaging, broken bones, or propeller lacerations (Knowlton and
Kraus, 2001). An animal at the surface could be struck directly by a
vessel, a surfacing animal could hit the bottom of a vessel, or an
animal just below the surface could be cut by a vessel's propeller.
Superficial strikes may not kill or result in the death of the animal.
Lethal interactions are typically associated with large whales, which
are occasionally found draped across the bulbous bow of large
commercial ships upon arrival in port. Although smaller cetaceans are
more maneuverable in relation to large vessels than are large whales,
as a general matter they may also be susceptible to strike.
The most vulnerable marine mammals are those that spend extended
periods of time at the surface in order to restore oxygen levels within
their tissues after deep dives (e.g., the sperm whale). In one recent
case, an Australian naval vessel struck both a mother fin whale and
calf off the coast of California. In addition, some baleen whales seem
generally unresponsive to vessel sound, making them more susceptible to
vessel collisions (Nowacek et al., 2004). These species are primarily
large, slow moving whales. Marine mammal responses to vessels may
include avoidance and changes in dive pattern (NRC, 2003).
Some researchers have suggested the relative risk of a vessel
strike can be assessed as a function of animal density and the
magnitude of vessel traffic (e.g., Fonnesbeck et al., 2008; Vanderlaan
et al., 2008). Differences among vessel types also influence the
probability of a vessel strike. The ability of any ship to detect a
marine mammal and avoid a collision depends on a variety of factors,
including environmental conditions, ship design, size, speed, and
ability and number of personnel observing, as well as the behavior of
the animal.
An examination of all known ship strikes from all shipping sources
(civilian and military) indicates vessel speed is a principal factor in
whether a
[[Page 49698]]
vessel strike occurs and, if so, whether it results in injury, serious
injury, or mortality (Knowlton and Kraus, 2001; Laist et al., 2001;
Jensen and Silber, 2003; Pace and Silber, 2005; Vanderlaan and Taggart,
2007; Conn and Silber 2013). Impact forces increase with speed, as does
the probability of a strike at a given distance (Silber et al., 2010;
Gende et al., 2011). For large vessels, speed and angle of approach can
influence the severity of a strike. In assessing records in which
vessel speed was known, Laist et al. (2001) found a direct relationship
between the occurrence of a whale strike and the speed of the vessel
involved in the collision. The authors concluded that most deaths
occurred when a vessel was traveling in excess of 13 kn.
Jensen and Silber (2003) detailed 292 records of known or probable
ship strikes of all large whale species from 1975 to 2002. Of these,
vessel speed at the time of collision was reported for 58 cases. Of
these 58 cases, 39 (or 67 percent) resulted in serious injury or death
(19 of those resulted in serious injury as determined by blood in the
water, propeller gashes or severed tailstock, and fractured skull, jaw,
vertebrae, hemorrhaging, massive bruising or other injuries noted
during necropsy and 20 resulted in death). Operating speeds of vessels
that struck various species of large whales ranged from 2 to 51 kn. The
majority (79 percent) of these strikes occurred at speeds of 13 kn or
greater. The average speed that resulted in serious injury or death was
18.6 kn. Pace and Silber (2005) found that the probability of death or
serious injury increased rapidly with increasing vessel speed.
Specifically, the predicted probability of serious injury or death
increased from 45 to 75 percent as vessel speed increased from 10 to 14
kn, and exceeded 90 percent at 17 kn. Higher speeds during collisions
result in greater force of impact and also appear to increase the
chance of severe injuries or death. While modeling studies have
suggested that hydrodynamic forces pulling whales toward the vessel
hull increase with increasing speed (Clyne, 1999; Knowlton et al.,
1995), this is inconsistent with Silber et al. (2010), which
demonstrated that there is no such relationship (i.e., hydrodynamic
forces are independent of speed).
In a separate study, Vanderlaan and Taggart (2007) analyzed the
probability of lethal mortality of large whales at a given speed,
showing that the greatest rate of change in the probability of a lethal
injury to a large whale as a function of vessel speed occurs between
8.6 and 15 kn. The chances of a lethal injury decline from
approximately 80 percent at 15 kn to approximately 20 percent at 8.6
kn. At speeds below 11.8 kn, the chances of lethal injury drop below 50
percent, while the probability asymptotically increases toward 100
percent above 15 kn.
Large whales also do not have to be at the water's surface to be
struck. Silber et al. (2010) found when a whale is below the surface
(about one to two times the vessel draft), there is likely to be a
pronounced propeller suction effect. This suction effect may draw the
whale into the hull of the ship, increasing the probability of
propeller strikes.
The Jensen and Silber (2003) report notes that the Large Whale Ship
Strike Database represents a minimum number of collisions, because the
vast majority probably goes undetected or unreported. In contrast, Navy
personnel are more likely to detect any strike that does occur because
of the required personnel training and Lookouts (as described in the
Proposed Mitigation Measures section), and they are required to report
all ship strikes involving marine mammals.
There are some key differences between the operation of military
and non-military vessels, which make the likelihood of a military
vessel striking a whale lower than some other vessels (e.g., commercial
merchant vessels), although as noted above strikes by naval vessels can
occur. Key differences include:
many military ships have their bridges positioned closer
to the bow, offering better visibility ahead of the ship (compared to a
commercial merchant vessel);
there are often aircraft associated with the training
activity (which can serve as Lookouts), which can more readily detect
cetaceans in the vicinity of a vessel or ahead of a vessel's present
course before crew on the vessel would be able to detect them;
military ships are generally more maneuverable than
commercial merchant vessels, and if cetaceans are spotted in the path
of the ship, could be capable of changing course more quickly;
the crew size on military vessels is generally larger than
merchant ships, allowing for stationing more trained Lookouts on the
bridge. At all times when vessels are underway, trained Lookouts and
bridge navigation teams are used to detect objects on the surface of
the water ahead of the ship, including cetaceans. Additional Lookouts,
beyond those already stationed on the bridge and on navigation teams,
are positioned as Lookouts during some training events; and
when submerged, submarines are generally slow moving (to
avoid detection) and therefore marine mammals at depth with a submarine
are likely able to avoid collision with the submarine. When a submarine
is transiting on the surface, there are Lookouts serving the same
function as they do on surface ships.
In the GOA Study Area, NMFS and the Navy have no documented vessel
strikes of marine mammals by the Navy. Therefore, NMFS has not used the
quantitative approach to assess the likelihood of vessel strikes used
in the Phase III incidental take rulemakings for Navy activities in the
Atlantic Fleet Training and Testing (AFTT) and Hawaii-Southern
California Training and Testing (HSTT) Study Areas, which starts with
the number of Navy strikes that have occurred in the study area in
question. But based on this lack of strikes and other factors described
below, which the Navy presented and NMFS agrees are appropriate factors
to consider in assessing the likelihood of ship strike, the Navy does
not anticipate vessel strikes and has not requested authorization to
take marine mammals by serious injury or mortality within the GOA Study
Area during training activities. Based on consideration of all
pertinent information, including, as appropriate, information on ship
strikes in other Navy study areas, NMFS agrees with the Navy's
conclusion based on the analysis and other factors described below.
Within Alaska waters, there were 28 reported marine mammal vessel
strikes between 2013 and 2017 (none of which were from U.S. Navy
vessels) (Delean et al., 2020), which is a primary consideration in the
evaluation of the likelihood that a strike by U.S. Navy vessels would
occur in the GOA Study Area in the next 7 years. Though not in the same
region, and noting the larger scale and differences in types of
activities that occur there, NMFS also considered the incidents of two
accidental ship strikes of large whales by U.S. Navy vessels in the
HSTT Study Area that occurred in June 2021 and July 2021 (the first
U.S. Navy ship strikes in the HSTT Study Area since 2009). The two ship
strikes were of large whales, but in both cases, the whale's species
could not be determined. Appropriately, as indicated in the Navy's 2022
application (87 FR 33113; June 1, 2022) to revise the 2020 HSTT
regulations (50 CFR part 218, subpart H) and LOAs, and as has been the
practice in NMFS analyses for all major Navy training and testing
rules, those strikes
[[Page 49699]]
would be quantitatively incorporated into the prediction of future
strikes in that region. However, due to differences across regions,
both in the density and occurrence of marine mammals, the levels and
types of activities, and other environmental factors--all of which
contribute to differences in the historical strikes in a given region--
strikes that occur in the HSTT Study Area are not quantitatively
considered in strike predictions for the GOA Study Area.
More broadly regarding the likelihood of strikes from U.S. Navy
vessels, large Navy vessels (greater than 18 m in length) within the
offshore areas of range complexes operate differently from commercial
vessels in ways that still likely reduce potential whale collisions.
Surface ships operated by or for the Navy have multiple personnel
assigned to stand watch at all times when a ship or surfaced submarine
is moving through the water (underway). A primary duty of personnel
standing watch on surface ships is to detect and report all objects and
disturbances sighted in the water that may indicate a threat to the
vessel and its crew, such as debris, a periscope, surfaced submarine,
or surface disturbance. Per vessel safety requirements, personnel
standing watch also report any marine mammals sighted in the path of
the vessel as a standard collision avoidance procedure. All vessels
proceed at a safe speed so they can take proper and effective action to
avoid a collision with any sighted object or disturbance, and can be
stopped within a distance appropriate to the prevailing circumstances
and conditions.
Between 2007 and 2009, the Navy developed and distributed
additional training, mitigation, and reporting tools to Navy operators
to improve marine mammal protection and to ensure compliance with LOA
requirements. In 2009, the Navy implemented Marine Species Awareness
Training designed to improve effectiveness of visual observation for
marine resources, including marine mammals. Additionally, for over a
decade, the Navy has implemented the Protective Measures Assessment
Protocol software tool, which provides operators with notification of
the required mitigation and a visual display of the planned training or
testing activity location overlaid with relevant environmental data.
Furthermore, specific to the Navy's proposed activities in the GOA
Study Area, the training activities would occur over a maximum of 21
days annually over a large area within the Gulf of Alaska, in
comparison to Navy activities that occur 365 days-per-year in other
Study Areas. The GOA Study Area activities would include one Carrier
Strike Group, which the Navy indicates would include up to six surface
vessels (though in some cases there could be more vessels, and in some
cases there could be fewer). Therefore, the Navy's activities in the
GOA Study Area would include an estimated 126 at-sea days (6 vessels x
21 days) annually. This level of potential Navy vessel activity is far
lower than vessel activity in other Study Areas. The estimated number
of at-sea days for Navy training activities in the GOA Study Area is
approximately 1/4th of that associated with Navy training and testing
in the Mariana Islands Training and Testing (MITT) Study Area (where
vessel strike is also not anticipated and has not occurred) over the
same time period, and approximately 1/36th of that associated with Navy
training and testing in the Hawaii-Southern California Training and
Testing (HSTT) Study Area (where limited vessel strike is authorized)
over the same time period. In addition to vessel strikes of large
whales being unlikely to occur for the reasons explained, the Navy
would implement certain additional mitigation measures that would
reduce the chance of a vessel strike even further. See the Proposed
Mitigation Measures section for more details.
Based on all of these considerations, NMFS has preliminarily
determined that the Navy's decision not to request incidental take
authorization for vessel strike of large whales is reasonable and
supported by multiple factors, including the lack of ship strike
reports in recent (2013-2017) stranding records for Alaska waters
(including no strikes by Navy vessels in the GOA Study Area; Delean et
al., 2020), the relatively small numbers of Navy vessels across a large
expanse of offshore waters in the GOA Study Area, the relatively short
activity period in which Navy vessels would operate (maximum of 21 days
per year), and the procedural mitigation measures that would be in
place to further minimize the potential for vessel strike.
In addition to the reasons listed above that make it unlikely that
the Navy would hit a large whale (more maneuverable ships, larger crew,
etc.), the following are additional reasons that vessel strike of
dolphins, small whales, and pinnipeds is very unlikely. Dating back
more than 20 years and for as long as it has kept records, the Navy has
no records of any small whales or pinnipeds being struck by a vessel as
a result of Navy activities. Over the same time period, NMFS and the
Navy have only one record of a dolphin being struck by a vessel as a
result of Navy activities. The dolphin was accidentally struck by a
Navy small boat in fall 2021 in Saint Andrew's Pass, Florida. The
smaller size and maneuverability of dolphins, small whales, and
pinnipeds generally make such strikes very unlikely. Other than this
one reported strike of a dolphin in 2021, NMFS has never received any
reports from other LOA or Incidental Harassment Authorization holders
indicating that these species have been struck by vessels. In addition,
worldwide ship strike records show little evidence of strikes of these
groups from the shipping sector and larger vessels, and the majority of
the Navy's activities involving faster-moving vessels (that could be
considered more likely to hit a marine mammal) are located in offshore
areas where smaller delphinid densities are lower. The majority of the
GOA Study Area is located offshore of the continental slope. While the
Navy's specified activities in the GOA Study Area do involve the use of
small boats also, use of small boats would occur on no more than 21
days per year, the length of the Navy's proposed training exercise.
Based on this information, NMFS concurs with the Navy's assessment that
vessel strike is not likely to occur for either large whales or smaller
marine mammals.
Marine Mammal Habitat
The Navy's proposed training activities could potentially affect
marine mammal habitat through the introduction of impacts to the prey
species of marine mammals, acoustic habitat (sound in the water
column), water quality, and biologically important habitat for marine
mammals. Each of these potential effects was considered in the 2020 GOA
DSEIS/OEIS and 2022 Supplement to the 2020 GOA DSEIS/OEIS, and based on
the information below and the supporting information included in the
2020 GOA DSEIS/OEIS, NMFS has preliminarily determined that the
proposed training activities would not have adverse or long-term
impacts on marine mammal habitat that would be expected to affect the
reproduction or survival of any marine mammals.
Effects to Prey
Sound may affect marine mammals through impacts on the abundance,
behavior, or distribution of prey species (e.g., crustaceans,
cephalopods, fish, zooplankton). Marine mammal prey varies by species,
season, and location and, for some species, is not well documented.
Here, we describe studies
[[Page 49700]]
regarding the effects of noise on known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
The most likely effects on fishes exposed to loud, intermittent, low-
frequency sounds are behavioral responses (i.e., flight or avoidance).
Short duration, sharp sounds (such as pile driving or air guns) can
cause overt or subtle changes in fish behavior and local distribution.
The reaction of fish to acoustic sources depends on the physiological
state of the fish, past exposures, motivation (e.g., feeding, spawning,
migration), and other environmental factors. Key impacts to fishes may
include behavioral responses, hearing damage, barotrauma (pressure-
related injuries), and mortality.
Fishes, like other vertebrates, have a variety of different sensory
systems to glean information from the ocean around them (Astrup and
Mohl, 1993; Astrup, 1999; Braun and Grande, 2008; Carroll et al., 2017;
Hawkins and Johnstone, 1978; Ladich and Popper, 2004; Ladich and
Schulz-Mirbach, 2016; Mann, 2016; Nedwell et al., 2004; Popper et al.,
2003; Popper et al., 2005). Depending on their hearing anatomy and
peripheral sensory structures, which vary among species, fishes hear
sounds using pressure and particle motion sensitivity capabilities and
detect the motion of surrounding water (Fay et al., 2008) (terrestrial
vertebrates generally only detect pressure). Most marine fishes
primarily detect particle motion using the inner ear and lateral line
system, while some fishes possess additional morphological adaptations
or specializations that can enhance their sensitivity to sound
pressure, such as a gas-filled swim bladder (Braun and Grande, 2008;
Popper and Fay, 2011).
Hearing capabilities vary considerably between different fish
species with data only available for just over 100 species out of the
34,000 marine and freshwater fish species (Eschmeyer and Fong, 2016).
In order to better understand acoustic impacts on fishes, fish hearing
groups are defined by species that possess a similar continuum of
anatomical features which result in varying degrees of hearing
sensitivity (Popper and Hastings, 2009a). There are four hearing groups
defined for all fish species (modified from Popper et al., 2014) within
this analysis and they include: fishes without a swim bladder (e.g.,
flatfish, sharks, rays, etc.); fishes with a swim bladder not involved
in hearing (e.g., salmon, cod, pollock, etc.); fishes with a swim
bladder involved in hearing (e.g., sardines, anchovy, herring, etc.);
and fishes with a swim bladder involved in hearing and high-frequency
hearing (e.g., shad and menhaden).
In terms of behavioral responses, Juanes et al. (2017) discuss the
potential for negative impacts from anthropogenic soundscapes on fish,
but the author's focus was on broader based sounds such as ship and
boat noise sources. There are no detonations of explosives occurring
underwater in the specified activity for this rulemaking, and
occasional behavioral reactions to intermittent explosions occurring
in-air at or above the water surface are unlikely to cause long-term
consequences for individual fish or populations. Fish that experience
hearing loss as a result of exposure to explosions may have a reduced
ability to detect relevant sounds such as predators, prey, or social
vocalizations. However, PTS has not been known to occur in fishes, and
any hearing loss in fish may be as temporary as the timeframe required
to repair or replace the sensory cells that were damaged or destroyed
(Popper et al., 2014; Popper et al., 2005; Smith et al., 2006). It is
not known if damage to auditory nerve fibers could occur and, if so,
whether fibers would recover during this process. It is also possible
for fish to be injured or killed by an explosion in the immediate
vicinity of the surface from dropped or fired ordnance. Physical
effects from pressure waves generated by in-air detonations at or above
the water surface could potentially affect fish within proximity of
training activities. The shock wave from an explosion occurring at or
above the water surface may be lethal to fish at close range, causing
massive organ and tissue damage and internal bleeding (Keevin and
Hempen, 1997). At greater distance from the detonation point, the
extent of mortality or injury depends on a number of factors, including
fish size, body shape, orientation, and species (Keevin and Hempen,
1997; Wright, 1982). At the same distance from the source, larger fish
are generally less susceptible to death or injury, elongated forms that
are round in cross-section are less at risk than deep-bodied forms, and
fish oriented sideways to the blast suffer the greatest impact (Edds-
Walton and Finneran, 2006; O'Keeffe, 1984; O'Keeffe and Young, 1984;
Wiley et al., 1981; Yelverton et al., 1975). Species with gas-filled
organs have a higher potential for mortality than those without them
(Gaspin, 1975; Gaspin et al., 1976; Goertner et al., 1994).
Nonetheless, Navy activities involving in-air explosions at or
above the water surface are dispersed in space and time; therefore,
repeated exposure of individual fishes is unlikely. Mortality and
injury effects to fishes from explosives would be localized around the
area of a given explosion at or above the water surface, but only if
individual fish and the explosive (and immediate pressure field) were
co-located at the same time. Fishes deeper in the water column or on
the bottom would not be affected by water surface explosions. Repeated
exposure of individual fish to sound and energy from Navy events
involving in-air detonations at or above the water surface is not
likely given fish movement patterns, especially schooling prey species.
Most acoustic effects, if any, are expected to be short term and
localized. Long-term consequences for fish populations, including key
prey species within the GOA Study Area, would not be expected.
Vessels and surface targets do not normally collide with adult
fish, most of which can detect and avoid them. Exposure of fishes to
vessel strike stressors is limited to those fish groups that are large,
slow moving, and may occur near the surface, such as basking sharks,
which are not marine mammal prey species. Vessel strikes would not pose
a risk to most of the other marine fish groups, because many fish can
detect and avoid vessel movements, making strikes extremely unlikely
and allowing the fish to return to their normal behavior after the ship
or device passes. As a vessel approaches a fish, it could have a
detectable behavioral or physiological response (e.g., swimming away
and increased heart rate) as the passing vessel displaces it. However,
such reactions are not expected to have effects on the survival,
growth, recruitment, or reproduction of these marine fish groups at the
population level.
In addition to fish, prey sources such as marine invertebrates
could potentially be impacted by sound stressors as a result of the
planned activities. Data on response of invertebrates such as squid has
been documented (de Soto, 2016; Sole et al., 2017). Sole et al. (2017)
reported physiological injuries to cuttlefish in cages placed at sea
when exposed during a controlled exposure experiment to low-frequency
sources (315 Hz, 139-142 dB re 1 [mu]Pa\2\ and 400 Hz, 139-141 dB re 1
[mu]Pa\2\). Fewtrell and McCauley (2012) reported squids maintained in
cages displayed startle responses and behavioral changes when exposed
to seismic air gun sonar (136-162 re 1 [mu]Pa\2\-s). However, the
sources Sole et al. (2017) and Fewtrell and
[[Page 49701]]
McCauley (2012) used are not similar and are much lower frequency than
typical Navy sources or those included in the Specified Activity within
the GOA Study Area. Nor do the studies address the issue of individual
displacement outside of a zone of impact when exposed to sound. Squids,
like most fish species, are likely more sensitive to low-frequency
sounds, and may not perceive mid- and high-frequency sonars such as
Navy sonars. As with fish, cumulatively individual and population-level
impacts from exposure to Navy sonar and explosives for squid are not
anticipated, and explosive impacts would be short term, localized, and
likely to be inconsequential to invertebrate populations.
Explosions could kill or injure other nearby marine invertebrates.
Vessels also have the potential to impact marine invertebrates by
disturbing the water column or sediments, or directly striking
organisms (Bishop, 2008). The propeller wash (water displaced by
propellers used for propulsion) from vessel movement and water
displaced from vessel hulls can potentially disturb marine
invertebrates in the water column and is a likely cause of zooplankton
mortality (Bickel et al., 2011). The localized and short-term exposure
to explosions or vessels could displace, injure, or kill zooplankton,
invertebrate eggs or larvae, and macro-invertebrates. However,
mortality or long-term consequences for a few animals is unlikely to
have measurable effects on overall stocks or populations. Long-term
consequences to marine invertebrate populations would not be expected
as a result of exposure to sounds or vessels in the GOA Study Area.
Military expended materials resulting from training could
potentially result in minor long term changes to benthic habitat.
Military expended materials may be colonized over time by benthic
organisms that prefer hard substrate and would provide structure that
could attract some species of fish or invertebrates. Overall, the
combined impacts of sound exposure, explosions, vessel strikes, and
military expended materials resulting from the specified activity would
not be expected to have measurable effects on populations of marine
mammal prey species and marine mammal habitat.
Acoustic Habitat
Acoustic habitat is the soundscape which encompasses all of the
sound present in a particular location and time, as a whole when
considered from the perspective of the animals experiencing it. Animals
produce sound for, or listen for sounds produced by, conspecifics
(communication during feeding, mating, and other social activities),
other animals (finding prey or avoiding predators), and the physical
environment (finding suitable habitats, navigating). Together, sounds
made by animals and the geophysical environment (e.g., produced by
earthquakes, lightning, wind, rain, waves) make up the natural
contributions to the total acoustics of a place. These acoustic
conditions, termed acoustic habitat, are one attribute of an animal's
total habitat.
Soundscapes are also defined by, and acoustic habitat influenced
by, the total contribution of anthropogenic sound. This may include
incidental emissions from sources such as vessel traffic or may be
intentionally introduced to the marine environment for data acquisition
purposes (as in the use of air gun arrays) or for Navy training
purposes (as in the use of sonar and other acoustic sources).
Anthropogenic noise varies widely in its frequency, content, duration,
and loudness, and these characteristics greatly influence the potential
habitat-mediated effects to marine mammals (please also see the
previous discussion on ``Masking''), which may range from local effects
for brief periods of time to chronic effects over large areas and for
longer durations. Depending on the extent of effects to habitat,
animals may alter their communications signals (thereby potentially
expending additional energy) or miss acoustic cues (either conspecific
or adventitious). Problems arising from a failure to detect cues are
more likely to occur when noise stimuli are chronic and overlap with
biologically relevant cues used for communication, orientation, and
predator/prey detection (Francis and Barber, 2013). For more detail on
these concepts see, e.g., Barber et al., 2009; Pijanowski et al., 2011;
Francis and Barber, 2013; Lillis et al., 2014, Hatch et al., 2016;
Duarte et al., 2021).
The term ``listening area'' refers to the region of ocean over
which sources of sound can be detected by an animal at the center of
the space. Loss of communication space concerns the area over which a
specific animal signal (used to communicate with conspecifics in
biologically important contexts such as foraging or mating) can be
heard, in noisier relative to quieter conditions (Clark et al., 2009).
Lost listening area concerns the more generalized contraction of the
range over which animals would be able to detect a variety of signals
of biological importance, including eavesdropping on predators and prey
(Barber et al., 2009). Such metrics do not, in and of themselves,
document fitness consequences for the marine animals that live in
chronically noisy environments. Long-term population-level consequences
mediated through changes in the ultimate survival and reproductive
success of individuals are difficult to study, and particularly so
underwater. However, it is increasingly well documented that aquatic
species rely on qualities of natural acoustic habitats, with
researchers quantifying reduced detection of important ecological cues
(e.g., Francis and Barber, 2013; Slabbekoorn et al., 2010) as well as
survivorship consequences in several species (e.g., Simpson et al.,
2014; Nedelec et al., 2015).
The sounds produced during Navy training activities can be widely
dispersed or concentrated in small areas for varying periods. Sound
produced from training activities in the GOA Study Area is temporary
and limited to a 21 consecutive day period from April to October,
unlike other Navy Study Areas where training occurs year-round. Any
anthropogenic noise attributed to training activities in the GOA Study
Area would be temporary and the affected area would be expected to
immediately return to the original state when these activities cease.
Water Quality
The 2011 GOA EIS/OEIS analyzed the potential effects on water
quality from explosives, explosive byproducts, and military expended
materials including their associated component metals and chemicals.
This analysis remains accurate and complete, and is incorporated by
reference in the 2016 GOA SEIS/OEIS and 2020 GOA DSEIS/OEIS. NMFS has
reviewed this analysis and concurs that it reflects the best available
science. High order explosions consume most of the explosive material,
creating typical combustion products. For example, in the case of Royal
Demolition Explosive, 98 percent of the products are common seawater
constituents and the remainder is rapidly diluted below levels that
would be expected to affect marine mammals. Explosion byproducts
associated with high order detonations present no secondary stressors
to marine mammals through sediment or water. However, low order
detonations and unexploded ordnance present a potential for exposure,
but only in the immediate vicinity of the ordnance. Degradation
products of Royal Demolition Explosive are not toxic to marine
organisms at realistic exposure levels (Carniel et al., 2019; Rosen and
Lotufo, 2010) and any remnant undetonated components from
[[Page 49702]]
explosives such as TNT, royal demolition explosive, and high melting
explosive experience rapid biological and photochemical degradation in
marine systems (Carniel et al., 2019; Cruz-Uribe et al., 2007; Juhasz
and Naidu, 2007; Pavlostathis and Jackson, 2002; Singh et al., 2009;
Walker et al., 2006).
The findings from multiple studies indicate the relatively low
solubility of most explosives and their degradation products, metals,
and chemicals meaning that concentrations of these contaminants in the
marine environment, including those associated with either high-order
or low-order detonations, are relatively low and readily diluted. A
series of studies of a World War II dump site off Hawaii have
demonstrated that only minimal concentrations of degradation products
were detected in the adjacent sediments and that there was no
detectable uptake in sampled organisms living on or in proximity to the
site (Briggs et al., 2016; Carniel et al., 2019; Edwards et al., 2016;
Hawaii Undersea Military Munitions Assessment, 2010; Kelley et al.,
2016; Koide et al., 2016). In the GOA Study Area, the concentration of
unexploded ordnance, explosion byproducts, metals, and other chemicals
would never exceed that of a World War II dump site. As another
example, the Canadian Forces Maritime Experimental and Test Ranges near
Nanoose, British Columbia, began operating in 1965 conducting test
events for both U.S. and Canadian forces, which included some of the
same activities proposed for the GOA Study Area. Environmental analyses
of the impacts from military expended materials at Nanoose were
documented in 1996 and 2005. The analyses concluded the Navy test
activities ``. . . had limited and perhaps negligible effects on the
natural environment'' (Environmental Science Advisory Committee, 2005).
Based on these and other similar applicable findings from multiple Navy
ranges, and based on the analysis in Section 3.3 (Water Resources) of
the 2011 GOA Final SEIS/OEIS (incorporated by reference in the 2020 GOA
Draft EIS/OEIS), indirect impacts on marine mammals from the training
activities in the GOA Study Area would be negligible and would have no
long-term effect on habitat.
Equipment used by the Navy within the GOA Study Area, including
ships and other marine vessels, aircraft, and other equipment, are also
potential sources of by-products. All equipment is properly maintained
in accordance with applicable Navy and legal requirements. All such
operating equipment meets Federal water quality standards, where
applicable.
Estimated Take of Marine Mammals
This section indicates the number of takes that NMFS is proposing
to authorize, which are based on the maximum amount of take that NMFS
anticipates is reasonably likely to occur. NMFS coordinated closely
with the Navy in the development of their incidental take application,
and preliminarily agrees that the methods the Navy has put forth
described herein to estimate take (including the model, thresholds, and
density estimates), and the resulting numbers are based on the best
available science and appropriate for authorization.
Takes would be in the form of harassment only. For a military
readiness activity, the MMPA defines ``harassment'' as (i) Any act that
injures or has the significant potential to injure a marine mammal or
marine mammal stock in the wild (Level A Harassment); or (ii) Any act
that disturbs or is likely to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of natural behavioral patterns,
including, but not limited to, migration, surfacing, nursing, breeding,
feeding, or sheltering, to a point where such behavioral patterns are
abandoned or significantly altered (Level B Harassment).
Proposed authorized takes would primarily be in the form of Level B
harassment, as use of the acoustic and explosive sources (i.e., sonar
and explosives) is most likely to result in the disruption of natural
behavioral patterns to a point where they are abandoned or
significantly altered (as defined specifically at the beginning of this
section, but referred to generally as behavioral disturbance) or TTS
for marine mammals. There is also the potential for Level A harassment,
in the form of auditory injury that results from exposure to the sound
sources utilized in training activities.
Generally speaking, for acoustic impacts NMFS estimates the amount
and type of harassment by considering: (1) acoustic thresholds above
which NMFS believes the best available science indicates marine mammals
would experience behavioral disturbance or incur some degree of
temporary or permanent hearing impairment; (2) the area or volume of
water that would be ensonified above these levels in a day or event;
(3) the density or occurrence of marine mammals within these ensonified
areas; and (4) the number of days of activities or events.
Acoustic Thresholds
Using the best available science, NMFS, in coordination with the
Navy, has established acoustic thresholds that identify the most
appropriate received level of underwater sound above which marine
mammals exposed to these sound sources could be reasonably expected to
experience a disruption in behavior patterns to a point where they are
abandoned or significantly altered (equated to onset of Level B
harassment), or to incur TTS onset (equated to Level B harassment) or
PTS onset (equated to Level A harassment). Thresholds have also been
developed to identify the pressure and impulse levels above which
animals may incur non-auditory injury or mortality from exposure to
explosive detonations (although no non-auditory injury from explosives
is anticipated as part of this rulemaking).
Despite the rapidly evolving science, there are still challenges in
quantifying expected behavioral responses that qualify as take by Level
B harassment, especially where the goal is to use one or two
predictable indicators (e.g., received level and distance) to predict
responses that are also driven by additional factors that cannot be
easily incorporated into the thresholds (e.g., context). So, while the
thresholds that identify Level B harassment by behavioral disturbance
(referred to as ``behavioral harassment thresholds'') have been refined
to better consider the best available science (e.g., incorporating both
received level and distance), they also still have some built-in
conservative factors to address the challenge noted. For example, while
duration of observed responses in the data are now considered in the
thresholds, some of the responses that are informing take thresholds
are of a very short duration, such that it is possible some of these
responses might not always rise to the level of disrupting behavior
patterns to a point where they are abandoned or significantly altered.
We describe the application of this behavioral harassment threshold as
identifying the maximum number of instances in which marine mammals
could be reasonably expected to experience a disruption in behavior
patterns to a point where they are abandoned or significantly altered.
In summary, we believe these behavioral harassment thresholds are the
most appropriate method for predicting Level B harassment by behavioral
disturbance given the best available science and the associated
uncertainty.
[[Page 49703]]
Hearing Impairment (TTS/PTS) and Non-Auditory Tissue Damage and
Mortality
NMFS' Acoustic Technical Guidance (NMFS, 2018) identifies dual
criteria to assess auditory injury (Level A harassment) to five
different marine mammal groups (based on hearing sensitivity) as a
result of exposure to noise from two different types of sources
(impulsive or non-impulsive). The Acoustic Technical Guidance also
identifies criteria to predict TTS, which is not considered injury and
falls into the Level B harassment category. The Navy's planned activity
includes the use of non-impulsive (sonar) and impulsive (explosives)
sources.
These thresholds (Table 5 and Table 6) were developed by compiling
and synthesizing the best available science and soliciting input
multiple times from both the public and peer reviewers. The references,
analysis, and methodology used in the development of the thresholds are
described in Acoustic Technical Guidance, which may be accessed at:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 5--Acoustic Thresholds Identifying the Onset of TTS and PTS for
Non-Impulsive Sound Sources by Functional Hearing Groups
------------------------------------------------------------------------
Non-impulsive
-------------------------------
Functional hearing group TTS threshold PTS threshold
SEL (weighted) SEL (weighted)
------------------------------------------------------------------------
Low-Frequency Cetaceans................. 179 199
Mid-Frequency Cetaceans................. 178 198
High-Frequency Cetaceans................ 153 173
Phocid Pinnipeds (Underwater)........... 181 201
Otarid Pinnipeds (Underwater)........... 199 219
------------------------------------------------------------------------
Note: SEL thresholds in dB re: 1 [mu]Pa\2\-s accumulated over a 24-hr
period.
Based on the best available science, the Navy (in coordination with
NMFS) used the acoustic and pressure thresholds indicated in Table 6 to
predict the onset of TTS, PTS, non-auditory tissue damage, and
mortality for explosives (impulsive) and other impulsive sound sources.
Table 6--Thresholds for TTS, PTS, Non-Auditory Tissue Damage, and Mortality Thresholds for Marine Mammals for Explosives
--------------------------------------------------------------------------------------------------------------------------------------------------------
Weighted onset TTS Slight GI tract Slight lung
Functional hearing group Species \1\ Weighted onset PTS injury injury Mortality
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans......... All mysticetes..... 168 dB SEL or 213 183 dB SEL or 219 243 dB Peak SPL.... Equation 1. Equation 2.
dB Peak SPL. dB Peak SPL.
Mid-frequency cetaceans......... Most delphinids, 170 dB SEL or 224 185 dB SEL or 230 243 dB Peak SPL....
medium and large dB Peak SPL. dB Peak SPL.
toothed whales.
High-frequency cetaceans........ Porpoises and Kogia 140 dB SEL or 196 155 dB SEL or 202 243 dB Peak SPL....
spp. dB Peak SPL. dB Peak SPL.
Phocidae........................ Harbor seal, 170 dB SEL or 212 185 dB SEL or 218 243 dB Peak SPL....
Hawaiian monk dB Peak SPL. dB Peak SPL.
seal, Northern
elephant seal.
Otariidae....................... California sea 188 dB SEL or 226 203 dB SEL or 232 243 dB Peak SPL....
lion, Guadalupe dB Peak SPL. dB Peak SPL.
fur seal, Northern
fur seal.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
Equation 1: 47.5M1/3 (1+[DRm/10.1])1/6 Pa-sec.
Equation 2: 103M1/3 (1+[DRm/10.1])1/6 Pa-sec.
M = mass of the animals in kg.
DRm = depth of the receiver (animal) in meters.
SPL = sound pressure level.
Weighted SEL thresholds in dB re: 1 [mu]Pa\2\-s accumulated over a 24-h period.
\1\ Peak thresholds are unweighted.
The criteria used to assess the onset of TTS and PTS due to
exposure to sonars (non-impulsive, see Table 5 above) are discussed
further in the Navy's rulemaking/LOA application (see Hearing Loss from
Sonar and Other Transducers in Chapter 6, Section 6.4.2.1, Methods for
Analyzing Impacts from Sonars and Other Transducers). Refer to the
Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects
Analysis (Phase III) report (U.S. Department of the Navy, 2017c) for
detailed information on how the criteria and thresholds were derived,
and to Section 3.8.3.1.1.2 of the 2020 GOA DSEIS/OEIS for a review of
TTS research published following development of the criteria and
thresholds applied in the Navy's analysis and in NMFS' Acoustic
Technical Guidance. Further, since publication of the 2020 GOA DSEIS/
OEIS, several additional studies associated with TTS in harbor
porpoises and seals have been published (e.g., Kastelein et al., 2020d;
Kastelein et al., 2021a and 2021b; Sills et al., 2020). NMFS is aware
of these recent papers and is currently working with the Navy to update
NMFS' Technical Guidance for Assessing the Effects of Anthropogenic
Sound on Marine Mammal Hearing Version 2.0 (Acoustic Technical
Guidance; NMFS 2018) to reflect relevant papers that have been
published since the 2018 update on our 3-5 year update schedule in the
Acoustic Technical Guidance. First, we
[[Page 49704]]
note that the recent peer-reviewed updated marine mammal noise exposure
criteria by Southall et al. (2019a) provide identical PTS and TTS
thresholds and weighting functions to those provided in NMFS' Acoustic
Technical Guidance.
NMFS will continue to review and evaluate new relevant data as it
becomes available and consider the impacts of those studies on the
Acoustic Technical Guidance to determine what revisions/updates may be
appropriate. However, any such revisions must undergo peer and public
review before being adopted, as described in the Acoustic Guidance
methodology. While some of the relevant data may potentially suggest
changes to TTS/PTS thresholds for some species, any such changes would
not be expected to change the predicted take estimates in a manner that
would change the necessary determinations supporting the issuance of
these regulations, and the data and values used in this rule reflect
the best available science.
Non-auditory injury (i.e., other than PTS) and mortality from sonar
and other transducers is so unlikely as to be discountable under normal
conditions for the reasons explained under the Potential Effects of
Specified Activities on Marine Mammals and Their Habitat section--
Acoustically-Induced Bubble Formation Due to Sonars and Other Pressure-
related Impacts and is therefore not considered further in this
analysis.
Level B Harassment by Behavioral Disturbance
Though significantly driven by received level, the onset of Level B
harassment by behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source (e.g., frequency, predictability, duty cycle), the environment
(e.g., bathymetry), and the receiving animals (hearing, motivation,
experience, demography, behavioral context) and can be difficult to
predict (Ellison et al., 2011; Southall et al., 2007). Based on what
the available science indicates and the practical need to use
thresholds based on a factor, or factors, that are both predictable and
measurable for most activities, NMFS uses generalized acoustic
thresholds based primarily on received level (and distance in some
cases) to estimate the onset of Level B harassment by behavioral
disturbance.
Sonar
As noted above, the Navy coordinated with NMFS to develop, and
propose for use in this rule, thresholds specific to their military
readiness activities utilizing active sonar that identify at what
received level and distance Level B harassment by behavioral
disturbance would be expected to result. These thresholds are referred
to as ``behavioral harassment thresholds'' throughout the rest of the
rule. These behavioral harassment thresholds consist of behavioral
response functions (BRFs) and associated cutoff distances, and are also
referred to, together, as ``the criteria.'' These criteria are used to
estimate the number of animals that may exhibit a behavioral response
that rises to the level of a take when exposed to sonar and other
transducers. The way the criteria were derived is discussed in detail
in the Criteria and Thresholds for U.S. Navy Acoustic and Explosive
Effects Analysis (Phase III) report (U.S. Department of the Navy,
2017c). Developing these behavioral harassment criteria involved
multiple steps. All peer-reviewed published behavioral response studies
conducted both in the field and on captive animals were examined in
order to understand the breadth of behavioral responses of marine
mammals to tactical sonar and other transducers. NMFS has carefully
reviewed the Navy's criteria, i.e., BRFs and cutoff distances for the
species, and agrees that it is the best available science and is the
appropriate method to use at this time for determining impacts to
marine mammals from military sonar and other transducers and for
calculating take and to support the determinations made in this
proposed rule.
As discussed above, marine mammal responses to sound (some of which
are considered disturbances that rise to the level of a take) are
highly variable and context specific, i.e., they are affected by
differences in acoustic conditions; differences between species and
populations; differences in gender, age, reproductive status, or social
behavior; and other prior experience of the individuals. This means
that there is support for considering alternative approaches for
estimating Level B harassment by behavioral disturbance. Although the
statutory definition of Level B harassment for military readiness
activities means that a natural behavior pattern of a marine mammal is
significantly altered or abandoned, the current state of science for
determining those thresholds is somewhat unsettled.
In its analysis of impacts associated with sonar acoustic sources
(which was coordinated with NMFS), the Navy used an updated
conservative approach that likely overestimates the number of takes by
Level B harassment due to behavioral disturbance and response. Many of
the behavioral responses identified using the Navy's quantitative
analysis are most likely to be of moderate severity as described in the
Southall et al. (2007) behavioral response severity scale. These
``moderate'' severity responses were considered significant if they
were sustained for the duration of the exposure or longer. Within the
Navy's quantitative analysis, many reactions are predicted from
exposure to sound that may exceed an animal's threshold for Level B
harassment by behavioral disturbance for only a single exposure (a few
seconds) to several minutes, and it is likely that some of the
resulting estimated behavioral responses that are counted as Level B
harassment would not constitute ``significantly altering or abandoning
natural behavioral patterns.'' The Navy and NMFS have used the best
available science to address the challenging differentiation between
significant and non-significant behavioral reactions (i.e., whether the
behavior has been abandoned or significantly altered such that it
qualifies as harassment), but have erred on the cautious side where
uncertainty exists (e.g., counting these lower duration reactions as
take), which likely results in some degree of overestimation of Level B
harassment by behavioral disturbance. We consider application of these
behavioral harassment thresholds, therefore, as identifying the maximum
number of instances in which marine mammals could be reasonably
expected to experience a disruption in behavior patterns to a point
where they are abandoned or significantly altered (i.e., Level B
harassment). Because this is the most appropriate method for estimating
Level B harassment given the best available science and uncertainty on
the topic, it is these numbers of Level B harassment by behavioral
disturbance that are analyzed in the Preliminary Analysis and
Negligible Impact Determination section and would be authorized.
In the Navy's acoustic impact analyses during Phase II (the
previous phase of Navy testing and training, 2017-2022, see also Navy's
Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects
Analysis Technical Report, 2012), the likelihood of Level B harassment
by behavioral disturbance in response to sonar and other transducers
was based on a probabilistic function (termed a BRF), that related the
likelihood (i.e., probability) of a behavioral response (at the level
of a Level B harassment) to the received SPL. The BRF was used to
estimate the percentage of an exposed population that is likely to
exhibit Level B
[[Page 49705]]
harassment due to altered behaviors or behavioral disturbance at a
given received SPL. This BRF relied on the assumption that sound poses
a negligible risk to marine mammals if they are exposed to SPL below a
certain ``basement'' value. Above the basement exposure SPL, the
probability of a response increased with increasing SPL. Two BRFs were
used in Navy acoustic impact analyses: BRF1 for mysticetes and BRF2 for
other species. BRFs were not used for beaked whales during Phase II
analyses. Instead, a step function at an SPL of 140 dB re: 1 [mu]Pa was
used for beaked whales as the threshold to predict Level B harassment
by behavioral disturbance. Similarly, a 120 dB re: 1 [mu]P step
function was used during Phase II for harbor porpoises.
Developing the behavioral harassment criteria for Phase III (the
current phase of Navy training and testing activities) involved
multiple steps: all available behavioral response studies conducted
both in the field and on captive animals were examined to understand
the breadth of behavioral responses of marine mammals to sonar and
other transducers (see also Navy's Criteria and Thresholds for U.S.
Navy Acoustic and Explosive Effects Analysis (Phase III) Technical
Report, 2017). Six behavioral response field studies with observations
of 14 different marine mammal species reactions to sonar or sonar-like
signals and 6 captive animal behavioral studies with observations of 8
different species reactions to sonar or sonar-like signals were used to
provide a robust data set for the derivation of the Navy's Phase III
marine mammal behavioral response criteria. The current criteria have
been rigorously vetted within the Navy community, among scientists
during expert elicitation, and then reviewed by the public before being
applied. All behavioral response research that has been published since
the derivation of the Navy's Phase III criteria (December 2016) has
been considered and is consistent with the current BRFs. While it is
unreasonable to revise and update the criteria and risk functions every
time a new study is published, these new studies provide additional
information, and NMFS and the Navy are considering them for updates to
the criteria in the future, when the next round of updated criteria
will be developed. The Navy and NMFS continue to evaluate the
information as new science becomes available.
Marine mammal species were placed into behavioral criteria groups
based on their known or suspected behavioral sensitivities to sound. In
most cases these divisions were driven by taxonomic classifications
(e.g., mysticetes, pinnipeds). The data from the behavioral studies
were analyzed by looking for significant responses, or lack thereof,
for each experimental session.
The Navy used cutoff distances beyond which the potential of
significant behavioral responses (and therefore Level B harassment) is
considered to be unlikely (see Table 7 below). These distances were
determined by examining all available published field observations of
behavioral reactions to sonar or sonar-like signals that included the
distance between the sound source and the marine mammal. The longest
distance, rounded up to the nearest 5-km increment, was chosen as the
cutoff distance for each behavioral criteria group (i.e., odontocetes,
pinnipeds, mysticetes, beaked whales, and harbor porpoise). For animals
within the cutoff distance, BRFs for each behavioral criteria group
based on a received SPL as presented in Chapter 6, Section 6.4.2.1
(Methods for Analyzing Impacts from Sonars and other Transducers) of
the Navy's rulemaking/LOA application were used to predict the
probability of a potential significant behavioral response. For
training activities that contain multiple platforms or tactical sonar
sources that exceed 215 dB re: 1 [mu]Pa at 1 m, this cutoff distance is
substantially increased (i.e., doubled) from values derived from the
literature. The use of multiple platforms and intense sound sources are
factors that probably increase responsiveness in marine mammals overall
(however, we note that helicopter dipping sonars were considered in the
intense sound source group, despite lower source levels, because of
data indicating that marine mammals are sometimes more responsive to
the less predictable employment of this source). There are currently
few behavioral observations under these circumstances; therefore, the
Navy conservatively predicted significant behavioral responses that
would rise to Level B harassment at farther ranges than shown in Table
7, versus less intense events.
Table 7--Cutoff Distances for Moderate Source Level, Single Platform Training Events and for All Other Events
With Multiple Platforms or Sonar With Source Levels at or Exceeding 215 dB re: 1 [micro]Pa at 1 m
----------------------------------------------------------------------------------------------------------------
Moderate SL/single
Criteria group platform cutoff distance High SL/multi-platform
(km) cutoff distance (km)
----------------------------------------------------------------------------------------------------------------
Odontocetes............................................... 10 20
Pinnipeds................................................. 5 10
Mysticetes................................................ 10 20
Beaked Whales............................................. 25 50
Harbor Porpoise........................................... 20 40
----------------------------------------------------------------------------------------------------------------
Notes: dB re: 1 [micro]Pa at 1 m = decibels referenced to 1 micropascal at 1 meter, km = kilometer, SL = source
level.
The range to received sound levels in 6-dB steps from three
representative sonar bins and the percentage of animals that may be
taken by Level B harassment under each BRF are shown in Tables 8
through 10. Cells are shaded if the mean range value for the specified
received level exceeds the distance cutoff distance for a particular
group and therefore are not included in the estimated take. See Chapter
6, Section 6.4.2.1 (Methods for Analyzing Impacts from Sonars and Other
Transducers) of the Navy's rulemaking/LOA application for further
details on the derivation and use of the BRFs, thresholds, and the
cutoff distances to identify takes by Level B harassment, which were
coordinated with NMFS. As noted previously, NMFS carefully reviewed,
and contributed to, the Navy's proposed behavioral harassment
thresholds (i.e., the BRFs and the cutoff distances) for the species,
and agrees that these methods represent the best available science at
this time for determining impacts to marine mammals from sonar and
other transducers.
Tables 8 through 10 identify the maximum likely percentage of
exposed individuals taken at the indicated received level and
associated range (in which marine mammals would be
[[Page 49706]]
reasonably expected to experience a disruption in behavior patterns to
a point where they are abandoned or significantly altered) for mid-
frequency active sonar (MFAS).
BILLING CODE 3510-22-P
[GRAPHIC] [TIFF OMITTED] TP11AU22.001
[[Page 49707]]
[GRAPHIC] [TIFF OMITTED] TP11AU22.002
[[Page 49708]]
[GRAPHIC] [TIFF OMITTED] TP11AU22.003
BILLING CODE 3510-22-C
Explosives
Phase III explosive criteria for behavioral harassment thresholds
for marine mammals is the functional hearing groups' TTS onset
threshold (in SEL) minus 5 dB (see Table 11 below and Table 6 for the
TTS thresholds for explosives) for events that contain multiple
impulses from explosives underwater. This is the same approach as taken
in Phase II for explosive analysis. See the Criteria and Thresholds for
U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) report
(U.S. Department of the Navy, 2017c) for detailed information on how
the criteria and thresholds were derived. NMFS continues to concur that
this approach represents the best available science for determining
impacts to marine mammals from explosives. As noted previously,
detonations occurring in air at a height of 33 ft (10 m) or less above
the water surface, and detonations occurring directly on the water
surface were modeled to detonate at a depth of 0.3 ft (0.1 m) below the
water surface. There are no detonations of explosives occurring
underwater as part of the planned activities.
Table 11--Thresholds for Level B Harassment by Behavioral Disturbance
for Explosives for Marine Mammals
------------------------------------------------------------------------
Functional hearing
Medium group SEL (weighted)
------------------------------------------------------------------------
Underwater........................ Low-frequency 163
cetaceans.
Underwater........................ Mid-frequency 165
cetaceans.
Underwater........................ High-frequency 135
cetaceans.
Underwater........................ Phocids............. 165
Underwater........................ Otariids............ 183
------------------------------------------------------------------------
Note: Weighted SEL thresholds in dB re: 1 [mu]Pa\2\s underwater
[[Page 49709]]
Navy's Acoustic Effects Model
The Navy's Acoustic Effects Model calculates sound energy
propagation from sonar and other transducers and explosives during
naval activities and the sound received by animat dosimeters. Animat
dosimeters are virtual representations of marine mammals distributed in
the area around the modeled naval activity and each dosimeter records
its individual sound ``dose.'' The model bases the distribution of
animats over the TMAA, the portion of the GOA Study Area where sonar
and other transducers and explosives are proposed for use, on the
density values in the Navy Marine Species Density Database and
distributes animats in the water column proportional to the known time
that species spend at varying depths.
The model accounts for environmental variability of sound
propagation in both distance and depth when computing the sound level
received by the animats. The model conducts a statistical analysis
based on multiple model runs to compute the estimated effects on
animals. The number of animats that exceed the thresholds for effects
is tallied to provide an estimate of the number of marine mammals that
could be affected.
Assumptions in the Navy model intentionally err on the side of
overestimation when there are unknowns. Naval activities are modeled as
though they would occur regardless of proximity to marine mammals,
meaning that no mitigation is considered (i.e., no power down or shut
down modeled) and without any avoidance of the activity by the animal.
The final step of the quantitative analysis of acoustic effects is to
consider the implementation of mitigation and the possibility that
marine mammals would avoid continued or repeated sound exposures. For
more information on this process, see the discussion in the Take
Request subsection below. All explosives used in the TMAA would
detonate in the air at or above the water surface. However, for this
analysis, detonations occurring in air at a height of 33 ft. (10 m) or
less above the water surface, and detonations occurring directly on the
water surface were modeled to detonate at a depth of 0.3 ft. (0.1 m)
below the water surface since there is currently no other identified
methodology for modeling potential effects to marine mammals that are
underwater as a result of detonations occurring at or above the surface
of the ocean. This overestimates the amount of explosive and acoustic
energy entering the water.
The model estimates the impacts caused by individual training
exercises. During any individual modeled event, impacts to individual
animats are considered over 24-hour periods. The animats do not
represent actual animals, but rather they represent a distribution of
animals based on density and abundance data, which allows for a
statistical analysis of the number of instances that marine mammals may
be exposed to sound levels resulting in an effect. Therefore, the model
estimates the number of instances in which an effect threshold was
exceeded over the course of a year, but does not estimate the number of
individual marine mammals that may be impacted over a year (i.e., some
marine mammals could be impacted several times, while others would not
experience any impact). A detailed explanation of the Navy's Acoustic
Effects Model is provided in the technical report Quantifying Acoustic
Impacts on Marine Mammals and Sea Turtles: Methods and Analytical
Approach for Phase III Training and Testing (U.S. Department of the
Navy, 2018).
Range to Effects
This section provides range to effects for sonar and other active
acoustic sources as well as explosives to specific acoustic thresholds
determined using the Navy Acoustic Effects Model. Marine mammals
exposed within these ranges for the shown duration are predicted to
experience the associated effect. Range to effects is important
information in not only predicting acoustic impacts, but also in
verifying the accuracy of model results against real-world situations
and determining adequate mitigation ranges to avoid higher level
effects, especially physiological effects to marine mammals.
Sonar
The ranges to received sound levels in 6-dB steps from three
representative sonar bins and the percentage of the total number of
animals that may be disturbed (and therefore Level B harassment) under
each BRF are shown in Table 8 though Table 10 above. See Chapter 6,
Section 6.4.2.1 (Methods for Analyzing Impacts from Sonars and Other
Transducers) of the Navy's rulemaking/LOA application for additional
details on the derivation and use of the BRFs, thresholds, and the
cutoff distances that are used to identify Level B harassment by
behavioral disturbance. NMFS has reviewed the range distance to effect
data provided by the Navy and concurs with the analysis.
The ranges to PTS for three representative sonar systems for an
exposure of 30 seconds is shown in Table 12 relative to the marine
mammal's functional hearing group. This period (30 seconds) was chosen
based on examining the maximum amount of time a marine mammal would
realistically be exposed to levels that could cause the onset of PTS
based on platform (e.g., ship) speed and a nominal animal swim speed of
approximately 1.5 m per second. The ranges provided in the table
include the average range to PTS, as well as the range from the minimum
to the maximum distance at which PTS is possible for each hearing
group.
Table 12--Ranges to Permanent Threshold Shift (Meters) for Three Representative Sonar Systems
----------------------------------------------------------------------------------------------------------------
Approximate range in meters for PTS from 30 second exposure \1\
Hearing group --------------------------------------------------------------------------
Sonar bin MF1 Sonar bin MF4 Sonar bin MF5
----------------------------------------------------------------------------------------------------------------
High-frequency cetaceans............. 180 (180-180) 31 (30-35) 9 (8-10)
Low-frequency cetaceans.............. 65 (65-65) 13 (0-15) 0 (0-0)
Mid-frequency cetaceans.............. 16 (16-16) 3 (3-3) 0 (0-0)
Otariids \2\......................... 6 (6-6) 0 (0-0) 0 (0-0)
Phocids \2\.......................... 45 (45-45) 11 (11-11) 0 (0-0)
----------------------------------------------------------------------------------------------------------------
\1\ PTS ranges extend from the sonar or other transducer sound source to the indicated distance. The average
range to PTS is provided as well as the range from the estimated minimum to the maximum range to PTS in
parenthesis.
\2\ Otariids and phocids are separated because true seals (phocids) generally dive much deeper than sea lions
and fur seals (otariids).
Notes: MF = mid-frequency, PTS = permanent threshold shift.
[[Page 49710]]
The tables below illustrate the range to TTS for 1, 30, 60, and 120
seconds from three representative sonar systems (see Table 13 through
Table 15).
Table 13--Ranges to Temporary Threshold Shift (Meters) for Sonar Bin MF1 Over a Representative Range of Environments Within the TMAA
--------------------------------------------------------------------------------------------------------------------------------------------------------
Approximate TTS ranges (meters) \1\
---------------------------------------------------------------------------------------------------
Hearing group Sonar bin MF1
---------------------------------------------------------------------------------------------------
1 second 30 seconds 60 seconds 120 seconds
--------------------------------------------------------------------------------------------------------------------------------------------------------
High-frequency cetaceans............................ 3,554 (1,525-6,775) 3,554 (1,525-6,775) 5,325 (2,275-9,525) 7,066 (2,525-13,025)
Low-frequency cetaceans............................. 920 (850-1,025) 920 (850-1,025) 1,415 (1,025-2,025) 2,394 (1,275-4,025)
Mid-frequency cetaceans............................. 209 (200-210) 209 (200-210) 301 (300-310) 376 (370-390)
Otariids............................................ 65 (65-65) 65 (65-65) 100 (100-110) 132 (130-140)
Phocids............................................. 673 (650-725) 673 (650-725) 988 (900-1,025) 1,206 (1,025-1,525)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Ranges to TTS represent the model predictions in different areas and seasons within the TMAA. The zone in which animals are expected to incur TTS
extends from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum
range to TTS in parenthesis.
Notes: MF = mid-frequency, TTS = temporary threshold shift.
Table 14--Ranges to Temporary Threshold Shift (Meters) for Sonar Bin MF4 Over a Representative Range of Environments Within the TMAA
--------------------------------------------------------------------------------------------------------------------------------------------------------
Approximate TTS ranges (meters) \1\
---------------------------------------------------------------------------------------------------
Hearing group Sonar bin MF4
---------------------------------------------------------------------------------------------------
1 second 30 seconds 60 seconds 120 seconds
--------------------------------------------------------------------------------------------------------------------------------------------------------
High-frequency cetaceans............................ 318 (220-550) 686 (430-1,275) 867 (575-1,525) 1,225 (825-2,025)
Low-frequency cetaceans............................. 77 (0-100) 175 (130-340) 299 (190-550) 497 (280-1,000)
Mid-frequency cetaceans............................. 22 (22-22) 35 (35-35) 50 (50-50) 71 (70-75)
Otariids............................................ 8 (8-8) 15 (15-15) 19 (19-19) 25 (25-25)
Phocids............................................. 67 (65-70) 123 (110-150) 172 (150-210) 357 (240-675)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Ranges to TTS represent the model predictions in different areas and seasons within the TMAA. The zone in which animals are expected to incur TTS
extends from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum
range to TTS in parenthesis.
Notes: MF = mid-frequency, TTS = temporary threshold shift.
Table 15--Ranges to Temporary Threshold Shift (Meters) for Sonar Bin MF5 Over a Representative Range of Environments Within the TMAA
--------------------------------------------------------------------------------------------------------------------------------------------------------
Approximate TTS ranges (meters) \1\
---------------------------------------------------------------------------------------------------
Hearing group Sonar bin MF5
---------------------------------------------------------------------------------------------------
1 second 30 seconds 60 seconds 120 seconds
--------------------------------------------------------------------------------------------------------------------------------------------------------
High-frequency cetaceans............................ 117 (110-140) 117 (110-140) 176 (150-320) 306 (210-800)
Low-frequency cetaceans............................. 9 (0-12) 9 (0-12) 13 (0-17) 19 (0-24)
Mid-frequency cetaceans............................. 5 (0-9) 5 (0-9) 12 (11-13) 18 (17-18)
Otariids............................................ 0 (0-0) 0 (0-0) 0 (0-0) 0 (0-0)
Phocids............................................. 9 (8-10) 9 (8-10) 14 (14-15) 21 (21-22)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Ranges to TTS represent the model predictions in different areas and seasons within the TMAA. The zone in which animals are expected to incur TTS
extends from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum
range to TTS in parenthesis.
Notes: MF = mid-frequency, TTS = temporary threshold shift.
Explosives
The following section provides the range (distance) over which
specific physiological or behavioral effects are expected to occur
based on the explosive criteria (see Chapter 6, Section 6.5.2 (Impacts
from Explosives) of the Navy's rulemaking/LOA application and the
Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects
Analysis (Phase III) report (U.S. Department of the Navy, 2017c)) and
the explosive propagation calculations from the Navy Acoustic Effects
Model (see Chapter 6, Section 6.5.2.2 (Impact Ranges for Explosives) of
the Navy's rulemaking/LOA application). The range to effects are shown
for a range of explosive bins, from E5 (greater than 5-10 lbs net
explosive weight) to E12 (greater than 650 lbs to 1,000 lbs net
explosive weight) (Tables 16 through 29). Ranges are determined by
modeling the distance that noise from an explosion would need to
propagate to reach exposure level thresholds specific to a hearing
group that would cause behavioral response (to the degree of Level B
harassment), TTS, PTS, and non-auditory injury. NMFS has reviewed the
range distance to effect data provided by the Navy and concurs with the
analysis. Range to effects is important information in not only
predicting impacts from explosives, but
[[Page 49711]]
also in verifying the accuracy of model results against real-world
situations and determining adequate mitigation ranges to avoid higher
level effects, especially physiological effects to marine mammals. For
additional information on how ranges to impacts from explosions were
estimated, see the technical report Quantifying Acoustic Impacts on
Marine Mammals and Sea Turtles: Methods and Analytical Approach for
Phase III Training and Testing (U.S. Navy, 2018).
Tables 16 through 27 show the minimum, average, and maximum ranges
to onset of auditory and likely behavioral effects that rise to the
level of Level B harassment based on the developed thresholds. Ranges
are provided for a representative source depth and cluster size (the
number of rounds fired, or buoys dropped, within a very short duration)
for each bin. For events with multiple explosions, sound from
successive explosions can be expected to accumulate and increase the
range to the onset of an impact based on SEL thresholds. Ranges to non-
auditory injury and mortality are shown in Table 28 and Table 29,
respectively.
No underwater detonations are planned as part of the Navy's
activities, but marine mammals could be exposed to in-air detonations
at or above the water surface. The Navy Acoustic Effects Model cannot
account for the highly non-linear effects of cavitation and surface
blow off for shallow underwater explosions, nor can it estimate the
explosive energy entering the water from a low-altitude detonation.
Thus, for this analysis, sources detonating in-air at or above (within
10 m above) the water surface are modeled as if detonating completely
underwater at a depth of 0.1 m, with all energy reflected into the
water rather than released into the air. Therefore, the amount of
explosive and acoustic energy entering the water, and consequently the
estimated ranges to effects, are likely to be overestimated.
Table 16 shows the minimum, average, and maximum ranges to onset of
auditory and likely behavioral effects that rise to the level of Level
B harassment for high-frequency cetaceans based on the developed
thresholds.
Table 16--SEL-Based Ranges to Onset PTS, Onset TTS, and Behavioral Disturbance (in Meters) for High-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Range to effects for explosives: high-frequency cetaceans \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
Source depth
Bin\2\ (m) Cluster size PTS TTS Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5........................................... 0.1 1 910 (850-975) 1,761 (1,275-2,275) 2,449 (1,775-3,275)
7 1,275 (1,025-1,525) 3,095 (2,025-4,525) 4,664 (2,275-7,775)
E9........................................... 0.1 1 1,348 (1,025-1,775) 3,615 (2,025-5,775) 5,365 (2,525-8,525)
E10.......................................... 0.1 1 1,546 (1,025-2,025) 4,352 (2,275-7,275) 5,949 (2,525-9,275)
E12.......................................... 0.1 1 1,713 (1,275-2,025) 5,115 (2,275-7,775) 6,831 (2,775-10,275)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses.
Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive
energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating ranges to effect. PTS = permanent
threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 17 shows the minimum, average, and maximum ranges to onset of
auditory effects for high-frequency cetaceans based on the developed
thresholds.
Table 17--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in Meters) for High Frequency Cetaceans
----------------------------------------------------------------------------------------------------------------
Range to effects for explosives: high-frequency cetaceans[sup1]
-----------------------------------------------------------------------------------------------------------------
Source depth
Bin \2\ (m) Cluster size PTS TTS
----------------------------------------------------------------------------------------------------------------
E5............................ 0.1 1 1,161 (1,000-1,525) 1,789 (1,025-2,275)
7 1,161 (1,000-1,525) 1,789 (1,025-2,275)
E9............................ 0.1 1 2,331 (1,525-2,775) 5,053 (2,025-9,275)
E10........................... 0.1 1 2,994 (1,775-4,525) 7,227 (2,025-14,775)
E12........................... 0.1 1 4,327 (2,025-7,275) 10,060 (2,025-22,275)
----------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 18 shows the minimum, average, and maximum ranges to onset of
auditory and likely behavioral effects that rise to the level of Level
B harassment for low-frequency cetaceans based on the developed
thresholds.
[[Page 49712]]
Table 18--SEL-Based Ranges to Onset PTS, Onset TTS, and Behavioral Disturbance (in Meters) for Low-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Range to effects for explosives: low-frequency cetaceans \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
Source depth
Bin \2\ (m) Cluster size PTS TTS Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5.............................................. 0.1 1 171 (100-190) 633 (230-825) 934 (310-1,525)
7 382 (170-450) 1,552 (380-5,775) 3,712 (600-13,025)
E9.............................................. 0.1 1 453 (180-550) 3,119 (550-9,025) 6,462 (1,275-19,275)
E10............................................. 0.1 1 554 (210-700) 4,213 (600-13,025) 9,472 (1,775-27,275)
E12............................................. 0.1 1 643 (230-825) 6,402 (1,275-19,775) 13,562 (2,025-34,775)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses.
Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive
energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating ranges to effect. PTS = permanent
threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 19 shows the minimum, average, and maximum ranges to onset of
auditory effects for low-frequency cetaceans based on the developed
thresholds.
Table 19--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in Meters) for Low Frequency Cetaceans
----------------------------------------------------------------------------------------------------------------
Range to effects for explosives: low-frequency cetaceans \1\
-----------------------------------------------------------------------------------------------------------------
Source depth
Bin \2\ (m) Cluster size PTS TTS
----------------------------------------------------------------------------------------------------------------
E5............................ 0.1 1 419 (170-500) 690 (210-875)
7 419 (170-500) 690 (210-875)
E9............................ 0.1 1 855 (270-1,275) 1,269 (400-1,775)
E10........................... 0.1 1 953 (300-1,525) 1,500 (450-2,525)
E12........................... 0.1 1 1,135 (360-1,525) 1,928 (525-4,775)
----------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 20 shows the minimum, average, and maximum ranges to onset of
auditory and likely behavioral effects that rise to the level of Level
B harassment for mid-frequency cetaceans based on the developed
thresholds.
Table 20--SEL-Based Ranges to Onset PTS, Onset TTS, and Behavioral Disturbance (in Meters) for Mid-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Range to effects for explosives: mid-frequency cetaceans \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
Source depth
Bin \2\ (m) Cluster size PTS TTS Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5........................................... 0.1 1 79 (75-80) 363 (360-370) 581 (550-600)
7 185 (180-190) 777 (650-825) 1,157 (800-1,275)
E9........................................... 0.1 1 215 (210-220) 890 (700-950) 1,190 (825-1,525)
E10.......................................... 0.1 1 275 (270-280) 974 (750-1,025) 1,455 (875-1,775)
E12.......................................... 0.1 1 340 (340-340) 1,164 (825-1,275) 1,746 (925-2,025)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses.
Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive
energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating ranges to effect. PTS = permanent
threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 21 shows the minimum, average, and maximum ranges to onset of
auditory effects for mid-frequency cetaceans based on the developed
thresholds.
[[Page 49713]]
Table 21--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in Meters) for Mid-Frequency Cetaceans
----------------------------------------------------------------------------------------------------------------
Range to effects for explosives: mid-frequency cetaceans[sup1]
-----------------------------------------------------------------------------------------------------------------
Source depth
Bin \2\ (m) Cluster size PTS TTS
----------------------------------------------------------------------------------------------------------------
E5............................ 0.1 1 158 (150-160) 295 (290-300)
7 158 (150-160) 295 (290-300)
E9............................ 0.1 1 463 (430-470) 771 (575-850)
E10........................... 0.1 1 558 (490-575) 919 (625-1,025)
E12........................... 0.1 1 679 (550-725) 1,110 (675-1,275)
----------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 22 shows the minimum, average, and maximum ranges to onset of
auditory and likely behavioral effects that rise to the level of Level
B harassment for otariid pinnipeds based on the developed thresholds.
Table 22--SEL-Based Ranges to Onset PTS, Onset TTS, and Behavioral Disturbance (in Meters) for Otariids
--------------------------------------------------------------------------------------------------------------------------------------------------------
Range to effects for explosives: otariids \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
Source depth
Bin \2\ (m) Cluster size PTS TTS Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5........................................... 0.1 1 25 (24-25) 110 (110-110) 185 (180-190)
7 58 (55-60) 265 (260-270) 443 (430-450)
E9........................................... 0.1 1 68 (65-70) 320 (310-330) 512 (490-525)
E10.......................................... 0.1 1 88 (85-90) 400 (390-410) 619 (575-675)
E12.......................................... 0.1 1 105 (100-110) 490 (470-500) 733 (650-825)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses.
Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive
energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating ranges to effect. PTS = permanent
threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 23 shows the minimum, average, and maximum ranges to onset of
auditory effects for otariid pinnipeds based on the developed
thresholds.
Table 23--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in Meters) for Otariids
----------------------------------------------------------------------------------------------------------------
Range to effects for explosives: otariids \1\
-----------------------------------------------------------------------------------------------------------------
Source depth
Bin \2\ (m) Cluster Size PTS TTS
----------------------------------------------------------------------------------------------------------------
E5.................................. 0.1 1 128 (120-130) 243 (240-250)
7 128 (120-130) 243 (240-250)
E9.................................. 0.1 1 383 (380-390) 656 (600-700)
E10................................. 0.1 1 478 (470-480) 775 (675-850)
E12................................. 0.1 1 583 (550-600) 896 (750-1,025)
----------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 24 shows the minimum, average, and maximum ranges to onset of
auditory and likely behavioral effects that rise to the level of Level
B harassment for phocid pinnipeds, excluding elephant seals, based on
the developed thresholds.
[[Page 49714]]
Table 24--SEL-Based Ranges to Onset PTS, Onset TTS, and Behavioral Disturbance (in Meters) for Phocids, Excluding Elephant Seals
--------------------------------------------------------------------------------------------------------------------------------------------------------
Range to effects for explosives: phocids \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
Source depth
Bin \2\ (m) Cluster size PTS TTS Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5.............................................. 0.1 1 150 (150-150) 681 (675-700) 1,009 (975-1,025)
7 360 (350-370) 1,306 (1,025-1,525) 1,779 (1,275-2,275)
E9.............................................. 0.1 1 425 (420-430) 1,369 (1,025-1,525) 2,084 (1,525-2,775)
E10............................................. 0.1 1 525 (525-525) 1,716 (1,275-2,275) 2,723 (1,525-4,025)
E12............................................. 0.1 1 653 (650-675) 1,935 (1,275-2,775) 3,379 (1,775-5,775)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Excluding elephant seals.
\2\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation environments in parentheses. No underwater
explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface is released
underwater, likely over-estimating ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\3\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 25 shows the minimum, average, and maximum ranges to onset of
auditory effects for phocids pinnipeds, excluding elephant seals, based
on the developed thresholds.
Table 25--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in Meters) for Phocids, Excluding Elephant
Seals
----------------------------------------------------------------------------------------------------------------
Range to effects for explosives: phocids \1\
-----------------------------------------------------------------------------------------------------------------
Source depth
Bin \2\ (m) Cluster size PTS TTS
----------------------------------------------------------------------------------------------------------------
E5............................ 0.1 1 537 (525-550) 931 (875-975)
7 537 (525-550) 931 (875-975)
E9............................ 0.1 1 1,150 (1,025-1,275) 1,845 (1,275-2,525)
E10........................... 0.1 1 1,400 (1,025-1,775) 2,067 (1,275-2,525)
E12........................... 0.1 1 1,713 (1,275-2,025) 2,306 (1,525-2,775)
----------------------------------------------------------------------------------------------------------------
\1\ Excluding elephant seals.
\2\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\3\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 26 shows the minimum, average, and maximum ranges to onset of
auditory and likely behavioral effects that rise to the level of Level
B harassment for elephant seals based on the developed thresholds.
Table 26--SEL-Based Ranges to Onset PTS, Onset TTS, and Behavioral Disturbance (in Meters) for Elephant Seals \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Range to effects for explosives: phocids (elephant seals) \2\
---------------------------------------------------------------------------------------------------------------------------------------------------------
Source depth
Bin \3\ (m) Cluster size PTS TTS Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5.............................................. 0.1 1 150 (150-150) 688 (675-700) 1,025 (1,025-1,025)
7 360 (350-370) 1,525 (1,525-1,525) 2,345 (2,275-2,525)
E9.............................................. 0.1 1 425 (420-430) 1,775 (1,775-1,775) 2,858 (2,775-3,275)
E10............................................. 0.1 1 525 (525-525) 2,150 (2,025-2,525) 3,421 (3,025-4,025)
E12............................................. 0.1 1 656 (650-675) 2,609 (2,525-3,025) 4,178 (3,525-5,775)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Elephant seals are separated from other phocids due to their dive behavior, which far exceeds the dive depths of the other phocids analyzed.
\2\ Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses.
Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive
energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating ranges to effect. PTS = permanent
threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
\3\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 27 shows the minimum, average, and maximum ranges to onset of
auditory effects for elephant seals, based on the developed thresholds.
[[Page 49715]]
Table 27--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in Meters) for Elephant Seals \1\
----------------------------------------------------------------------------------------------------------------
Range to effects for explosives: phocids (elephant seals) \2\
-----------------------------------------------------------------------------------------------------------------
Source depth
Bin \3\ (m) Cluster size PTS TTS
----------------------------------------------------------------------------------------------------------------
E5............................ 0.1 1 537 (525-550) 963 (950-975)
7 537 (525-550) 963 (950-975)
E9............................ 0.1 1 1,275 (1,275-1,275) 2,525 (2,525-2,525)
E10........................... 0.1 1 1,775 (1,775-1,775) 3,046 (3,025-3,275)
E12........................... 0.1 1 2,025 (2,025-2,025) 3,539 (3,525-3,775)
----------------------------------------------------------------------------------------------------------------
\1\ Elephant seals are separated from other phocids due to their dive behavior, which far exceeds the dive
depths of the other phocids analyzed.
\2\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\3\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
Table 28 shows the minimum, average, and maximum ranges due to
varying propagation conditions to non-auditory injury as a function of
animal mass and explosive bin (i.e., net explosive weight). Ranges to
gastrointestinal tract injury typically exceed ranges to slight lung
injury; therefore, the maximum range to effect is not mass-dependent.
Animals within these water volumes would be expected to receive minor
injuries at the outer ranges, increasing to more substantial injuries,
and finally mortality as an animal approaches the detonation point.
Table 28--Ranges to 50 Percent Non-Auditory Injury for All Marine Mammal
Hearing Groups
------------------------------------------------------------------------
Range to non-
Bin \1\ auditory injury
(meters) \2\
------------------------------------------------------------------------
E5................................................ 40 (40-40)
E9................................................ 121 (90-130)
E10............................................... 152 (100-160)
E12............................................... 190 (110-200)
------------------------------------------------------------------------
\1\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10
(>250-500), E12 (>650-1,000).
\2\ Average distance (m) is shown with the minimum and maximum distances
due to varying propagation environments in parentheses.
Notes: All ranges to non-auditory injury within this table are driven by
gastrointestinal tract injury thresholds regardless of animal mass.
Ranges to mortality, based on animal mass, are shown in Table 29
below.
Table 29--Ranges to 50 Percent Mortality Risk for All Marine Mammal Hearing Groups as a Function of Animal Mass
--------------------------------------------------------------------------------------------------------------------------------------------------------
Animal mass intervals (kg) \2\
Bin \1\ -----------------------------------------------------------------------------------------------------------------
10 250 1,000 5,000 25,000 72,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5.................................... 13 (12-14) 7 (4-11) 3 (3-4) 2 (1-3) 1 (1-1) 1 (0-1)
E9.................................... 35 (30-40) 20 (13-30) 10 (9-13) 7 (6-9) 4 (3-4) 3 (2-3)
E10................................... 43 (40-50) 25 (16-40) 13 (11-16) 9 (7-11) 5 (4-5) 4 (3-4)
E12................................... 55 (50-60) 30 (20-50) 17 (14-20) 11 (9-14) 6 (5-7) 5 (4-6)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
\2\ Average distance (m) to mortality is depicted above the minimum and maximum distances, which are in parentheses for each animal mass interval.
Marine Mammal Density
A quantitative analysis of impacts on a species or stock requires
data on their abundance and distribution that may be affected by
anthropogenic activities in the potentially impacted area. The most
appropriate metric for this type of analysis is density, which is the
number of animals present per unit area. Marine species density
estimation requires a significant amount of effort to both collect and
analyze data to produce a reasonable estimate. Unlike surveys for
terrestrial wildlife, many marine species spend much of their time
submerged, and are not easily observed. In order to collect enough
sighting data to make reasonable density estimates, multiple
observations are required, often in areas that are not easily
accessible (e.g., far offshore). Ideally, marine mammal species
sighting data would be collected for the specific area and time period
(e.g., season) of interest and density estimates derived accordingly.
However, in many places, poor weather conditions and high sea states
prohibit the completion of comprehensive visual surveys.
For most cetacean species, abundance is estimated using line-
transect surveys or mark-recapture studies (e.g., Barlow, 2010; Barlow
and Forney, 2007; Calambokidis et al., 2008). The result provides one
single density estimate value for each species across broad geographic
areas. This is the general approach applied in estimating cetacean
abundance in NMFS' Stock Assessment Reports (SARs). Although the single
value provides a good average estimate of abundance (total number of
individuals) for a specified area, it does not provide information on
the species distribution or concentrations within that area, and it
does not estimate density for other timeframes or seasons that were not
surveyed. More recently, spatial habitat modeling developed by NMFS'
Southwest Fisheries Science Center has been used to estimate cetacean
densities (Barlow et al., 2009; Becker et al., 2010, 2012a, 2012b,
2012c, 2014, 2016; Ferguson et al., 2006a; Forney et al., 2012, 2015;
Redfern et al., 2006). These models estimate cetacean density as a
continuous function of habitat variables (e.g., sea surface
temperature, seafloor depth, etc.) and thus allow predictions of
cetacean
[[Page 49716]]
densities on finer spatial scales than traditional line-transect or
mark recapture analyses and for areas that have not been surveyed.
Within the geographic area that was modeled, densities can be predicted
wherever these habitat variables can be measured or estimated.
Ideally, density data would be available for all species throughout
the study area year-round, in order to best estimate the impacts of
Navy activities on marine species. However, in many places ship
availability, lack of funding, inclement weather conditions, and high
sea states prevent the completion of comprehensive year-round surveys.
Even with surveys that are completed, poor conditions may result in
lower sighting rates for species that would typically be sighted with
greater frequency under favorable conditions. Lower sighting rates
preclude having an acceptably low uncertainty in the density estimates.
A high level of uncertainty, indicating a low level of confidence in
the density estimate, is typical for species that are rare or difficult
to sight. In areas where survey data are limited or non-existent, known
or inferred associations between marine habitat features and the likely
presence of specific species are sometimes used to predict densities in
the absence of actual animal sightings. Consequently, there is no
single source of density data for every area, species, and season
because of the fiscal costs, resources, and effort involved in
providing enough survey coverage to sufficiently estimate density.
To characterize marine species density for large oceanic regions,
the Navy reviews, critically assesses, and prioritizes existing density
estimates from multiple sources, requiring the development of a
systematic method for selecting the most appropriate density estimate
for each combination of species/stock, area, and season. The selection
and compilation of the best available marine species density data
resulted in the Navy Marine Species Density Database (NMSDD), which
includes seasonal density values for every marine mammal species and
stock present within the TMAA. This database is described in the
technical report titled U.S. Navy Marine Species Density Database Phase
III for the Gulf of Alaska Temporary Maritime Activities Area (U.S.
Department of the Navy, 2021), hereafter referred to as the Density
Technical Report. NMFS vetted all cetacean densities by the Navy prior
to use in the Navy's acoustic analysis for the current rulemaking
process.
A variety of density data and density models are needed in order to
develop a density database that encompasses the entirety of the TMAA
(densities beyond the TMAA were not considered because sonar and other
transducers and explosives would not be used in the GOA Study Area
beyond the TMAA). Because this data is collected using different
methods with varying amounts of accuracy and uncertainty, the Navy has
developed a hierarchy to ensure the most accurate data is used when
available. The Density Technical Report describes these models in
detail and provides detailed explanations of the models applied to each
species density estimate. The below list describes models in order of
preference.
1. Spatial density models are preferred and used when available
because they provide an estimate with the least amount of uncertainty
by deriving estimates for divided segments of the sampling area. These
models (see Becker et al., 2016; Forney et al., 2015) predict spatial
variability of animal presence as a function of habitat variables
(e.g., sea surface temperature, seafloor depth, etc.). This model is
developed for areas, species, and, when available, specific timeframes
(months or seasons) with sufficient survey data; therefore, this model
cannot be used for species with low numbers of sightings.
2. Stratified design-based density estimates use line-transect
survey data with the sampling area divided (stratified) into sub-
regions, and a density is predicted for each sub-region (see Barlow,
2016; Becker et al., 2016; Bradford et al., 2017; Campbell et al.,
2014; Jefferson et al., 2014). While geographically stratified density
estimates provide a better indication of a species' distribution within
the study area, the uncertainty is typically high because each sub-
region estimate is based on a smaller stratified segment of the overall
survey effort.
3. Design-based density estimations use line-transect survey data
from vessel and aerial surveys designed to cover a specific geographic
area (see Carretta et al., 2015). These estimates use the same survey
data as stratified design-based estimates, but are not segmented into
sub-regions and instead provide one estimate for a large surveyed area.
Relative environmental suitability (RES) models provide estimates
for areas of the oceans that have not been surveyed using information
on species occurrence and inferred habitat associations and have been
used in past density databases, however, these models were not used in
the current quantitative analysis.
The Navy describes some of the challenges of interpreting the
results of the quantitative analysis summarized above and described in
the Density Technical Report: ``It is important to consider that even
the best estimate of marine species density is really a model
representation of the values of concentration where these animals might
occur. Each model is limited to the variables and assumptions
considered by the original data source provider. No mathematical model
representation of any biological population is perfect, and with
regards to marine mammal biodiversity, any single model method will not
completely explain the actual distribution and abundance of marine
mammal species. It is expected that there would be anomalies in the
results that need to be evaluated, with independent information for
each case, to support if we might accept or reject a model or portions
of the model'' (U.S. Department of the Navy, 2017a).
The Navy's estimate of abundance (based on the density estimates
used) in the TMAA may differ from population abundances estimated in
NMFS' SARs in some cases for a variety of reasons. Models may predict
different population abundances for many reasons. The models may be
based on different data sets or different temporal predictions may be
made. The SARs are often based on single years of NMFS surveys, whereas
the models used by the Navy generally include multiple years of survey
data from NMFS, the Navy, and other sources. To present a single, best
estimate, the SARs often use a single season survey where they have the
best spatial coverage (generally summer). Navy models often use
predictions for multiple seasons, where appropriate for the species,
even when survey coverage in non-summer seasons is limited, to
characterize impacts over multiple seasons as Navy activities may occur
outside of the summer months. Predictions may be made for different
spatial extents. Many different, but equally valid, habitat and density
modeling techniques exist and these can also be the cause of
differences in population predictions. Differences in population
estimates may be caused by a combination of these factors. Even similar
estimates should be interpreted with caution and differences in models
fully understood before drawing conclusions.
In particular, the global population structure of humpback whales,
with 14 DPSs all associated with multiple feeding areas at which
individuals from multiple DPSs convene, is another reason that SAR
abundance estimates can differ from other estimates and be somewhat
confusing--the same individuals are addressed in multiple
[[Page 49717]]
SARs. For some species, the stock assessment for a given species may
exceed the Navy's density prediction because those species' home range
extends beyond the GOA Study Area or TMAA boundaries. The primary
source of density estimates are geographically specific survey data and
either peer-reviewed line-transect estimates or habitat-based density
models that have been extensively validated to provide the most
accurate estimates possible.
These factors and others described in the Density Technical Report
should be considered when examining the estimated impact numbers in
comparison to current population abundance information for any given
species or stock. For a detailed description of the density and
assumptions made for each species, see the Density Technical Report.
NMFS coordinated with the Navy in the development of its take
estimates and concurs that the Navy's approach for density
appropriately utilizes the best available science. Later, in the
Preliminary Analysis and Negligible Impact Determination section, we
assess how the estimated take numbers compare to stock abundance in
order to better understand the potential number of individuals
impacted, and the rationale for which abundance estimate is used is
included there.
Take Request
The 2020 GOA DSEIS/OEIS considered all training activities proposed
to occur in the TMAA, and the 2022 Supplement to the 2020 GOA DSEIS/
OEIS considered all training activities proposed to occur in the WMA,
together for which they covered all activities proposed for the GOA
Study Area. The Navy's rulemaking/LOA application described the
activities that are reasonably likely to result in the MMPA-defined
take of marine mammals, all of which would occur in the TMAA portion of
the GOA Study Area. The Navy determined that the two stressors below
could result in the incidental taking of marine mammals. NMFS has
reviewed the Navy's data and analysis for the entire Study Area and
determined that it is complete and accurate, and agrees that the
following stressors have the potential to result in takes by harassment
of marine mammals from the Navy's planned activities.
Acoustics (sonar and other transducers); and
Explosives (explosive shock wave and sound, assumed to
encompass the risk due to fragmentation).
The quantitative analysis process used to estimate potential
exposures to marine mammals resulting from acoustic and explosive
stressors for the Navy's take request in the rulemaking/LOA application
and the 2020 GOA DSEIS/OEIS is detailed in the technical report titled
Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods
and Analytical Approach for Phase III Training and Testing (U.S.
Department of the Navy, 2018). The Navy Acoustic Effects Model
estimates acoustic and explosive effects without taking mitigation into
account; therefore, the model overestimates predicted impacts on marine
mammals within mitigation zones.
To account for mitigation for marine species in the take estimates,
the Navy conducts a quantitative assessment of mitigation. The Navy
conservatively quantifies the manner in which procedural mitigation is
expected to reduce the risk for model-estimated PTS for exposures to
sonars and for model-estimated mortality for exposures to explosives,
based on species sightability, observation area, visibility, and the
ability to exercise positive control over the sound source. Where the
analysis indicates mitigation would effectively reduce risk, the model-
estimated PTS are considered reduced to TTS and the model-estimated
mortalities are considered reduced to injury, though, for training
activities in the GOA Study Area, no mortality or non-auditory injury
is anticipated, even without consideration of planned mitigation
measures. For a complete explanation of the process for assessing the
effects of mitigation, see the Navy's rulemaking/LOA application
(Section 6: Take Estimates for Marine Mammals, and Section 11:
Mitigation Measures) and the technical report titled Quantifying
Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and
Analytical Approach for Phase III Training and Testing (U.S. Department
of the Navy, 2018). The extent to which the mitigation areas reduce
impacts on the affected species is addressed separately in the
Preliminary Analysis and Negligible Impact Determination section.
The Navy assesses the effectiveness of its procedural mitigation
measures on a per-scenario basis for four factors: (1) species
sightability, (2) a Lookout's ability to observe the range to PTS (for
sonar and other transducers) and range to mortality (for explosives,
although for this rule the Navy's modeling indicated that no mortality
would occur), (3) the portion of time when mitigation could potentially
be conducted during periods of reduced daytime visibility (to include
inclement weather and high sea-state) and the portion of time when
mitigation could potentially be conducted at night, and (4) the ability
for sound sources to be positively controlled (e.g., powered down).
During training activities, there is typically at least one, if not
numerous, support personnel involved in the activity (e.g., range
support personnel aboard a torpedo retrieval boat or support aircraft).
In addition to the Lookout posted for the purpose of mitigation, these
additional personnel observe and disseminate marine species sighting
information amongst the units participating in the activity whenever
possible as they conduct their primary mission responsibilities.
However, as a conservative approach to assigning mitigation
effectiveness factors, the Navy elected to only account for the minimum
number of required Lookouts used for each activity; therefore, the
mitigation effectiveness factors may underestimate the likelihood that
some marine mammals may be detected during activities that are
supported by additional personnel who may also be observing the
mitigation zone.
For a rulemaking where NMFS and the Navy determine that the planned
activities, such as use of explosives, could cause mortality, the Navy
would use the equations in the below sections to calculate the
reduction in model-estimated mortality impacts due to implementing
procedural mitigation.
Equation 1:
Mitigation Effectiveness = Species Sightability x Visibility x
Observation Area x Positive Control
Species Sightability is the ability to detect marine mammals and is
dependent on the animal's presence at the surface and the
characteristics of the animal that influence its sightability. The Navy
considered applicable data from the best available science to
numerically approximate the sightability of marine mammals and
determined the standard ``detection probability'' referred to as g(0)
is most appropriate. Also, Visibility = 1- sum of individual visibility
reduction factors; Observation Area = portion of impact range that can
be continuously observed during an event; and Positive Control =
positive control factor of all sound sources involving mitigation. For
further details on these mitigation effectiveness factors please refer
to the technical report titled Quantifying Acoustic Impacts on Marine
Mammals and Sea Turtles: Methods and Analytical Approach for Phase III
Training and Testing (U.S. Department of the Navy, 2018).
To quantify the number of marine mammals predicted to be sighted by
Lookouts in the injury zone during
[[Page 49718]]
implementation of procedural mitigation for sonar and other
transducers, the species sightability is multiplied by the mitigation
effectiveness scores and number of model-estimated PTS impacts, as
shown in the equation below:
Equation 2:
Number of Animals Sighted by Lookouts = Mitigation Effectiveness x
Model - Estimated Impacts
The marine mammals sighted by Lookouts in the injury zone during
implementation of mitigation, as calculated by the equation above,
would not be exposed to these higher level impacts. To quantify the
number of marine mammals predicted to be sighted by Lookouts in the
mortality zone during implementation of procedural mitigation during
events using explosives (if any mortality were anticipated to occur),
the species sightability is multiplied by the mitigation effectiveness
scores and number of model-estimated mortality impacts, as shown in
equation 1 above. The marine mammals predicted to be sighted in the
mortality zone by Lookouts during implementation of procedural
mitigation, as calculated by the above equation 2, are not predicted to
be exposed in these ranges. The Navy corrects the category of predicted
impact for the number of animals sighted within the mitigation zone,
but does not modify the total number of animals predicted to experience
impacts from the scenario. For example, the number of animals sighted
(i.e., number of animals that will avoid mortality) is first subtracted
from the model-predicted mortality impacts, and then added to the
model-predicted injurious impacts.
The NAEMO model overestimates the number of marine mammals that
would be exposed to sound sources that could cause PTS because the
model does not consider horizontal movement of animats, including
avoidance of high intensity sound exposures. Therefore, the potential
for animal avoidance is considered separately. At close ranges and high
sound levels, avoidance of the area immediately around the sound source
is one of the assumed behavioral responses for marine mammals. Animal
avoidance refers to the movement out of the immediate injury zone for
subsequent exposures, not wide-scale area avoidance. Various
researchers have demonstrated that cetaceans can perceive the location
and movement of a sound source (e.g., vessel, seismic source, etc.)
relative to their own location and react with responsive movement away
from the source, often at distances of 1 km or more (Au and Perryman,
1982; Jansen et al., 2010; Richardson et al., 1995; Tyack et al., 2011;
Watkins, 1986; W[uuml]rsig et al., 1998). A marine mammal's ability to
avoid a sound source and reduce its cumulative sound energy exposure
would reduce risk of both PTS and TTS. However, the quantitative
analysis conservatively only considers the potential to reduce some
instances of PTS by accounting for marine mammals swimming away to
avoid repeated high-level sound exposures. All reductions in PTS
impacts from likely avoidance behaviors are instead considered TTS
impacts.
NMFS coordinated with the Navy in the development of this
quantitative method to address the effects of procedural mitigation on
acoustic and explosive exposures and takes, and NMFS independently
reviewed and concurs with the Navy that it is appropriate to
incorporate the quantitative assessment of mitigation into the take
estimates based on the best available science. We reiterate, however,
that no mortality was modeled for the GOA TMAA activities, and as
stated above, the Navy does not propose the use of sonar and other
transducers and explosives in the WMA. Therefore, this method was not
applied here, as it relates to modeled mortality. This method was
applied to potential takes by PTS resulting from sonar and other
transducers in the TMAA, but not for the use of explosives. For
additional information on the quantitative analysis process and
mitigation measures, refer to the technical report titled Quantifying
Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and
Analytical Approach for Phase III Training and Testing (U.S. Department
of the Navy, 2018) and Chapter 6 (Take Estimates for Marine Mammals)
and Chapter 11 (Mitigation Measures) of the Navy's rulemaking/LOA
application.
As a general matter, NMFS does not prescribe the methods for
estimating take for any applicant, but we review and ensure that
applicants use the best available science, and methodologies that are
logical and technically sound. Applicants may use different methods of
calculating take (especially when using models) and still get to a
result that is representative of the best available science and that
allows for a rigorous and accurate evaluation of the effects on the
affected populations. There are multiple pieces of the Navy take
estimation methods--propagation models, animat movement models, and
behavioral thresholds, for example. NMFS evaluates the acceptability of
these pieces as they evolve and are used in different rules and impact
analyses. Some of the pieces of the Navy's take estimation process have
been used in Navy incidental take rules since 2009 and have undergone
multiple public comment processes; all of them have undergone extensive
internal Navy review, and all of them have undergone comprehensive
review by NMFS, which has sometimes resulted in modifications to
methods or models.
The Navy uses rigorous review processes (verification, validation,
and accreditation processes; peer and public review) to ensure the data
and methodology it uses represent the best available science. For
instance, the NAEMO model is the result of a NMFS-led Center for
Independent Experts (CIE) review of the components used in earlier
models. The acoustic propagation component of the NAEMO model (CASS/
GRAB) is accredited by the Oceanographic and Atmospheric Master Library
(OAML), and many of the environmental variables used in the NAEMO model
come from approved OAML databases and are based on in-situ data
collection. The animal density components of the NAEMO model are base
products of the NMSDD, which includes animal density components that
have been validated and reviewed by a variety of scientists from NMFS
Science Centers and academic institutions. Several components of the
model, for example the Duke University habitat-based density models,
have been published in peer reviewed literature. Others like the
Atlantic Marine Assessment Program for Protected Species, which was
conducted by NMFS Science Centers, have undergone quality assurance and
quality control (QA/QC) processes. Finally, the NAEMO model simulation
components underwent QA/QC review and validation for model parts such
as the scenario builder, acoustic builder, scenario simulator, etc.,
conducted by qualified statisticians and modelers to ensure accuracy.
Other models and methodologies have gone through similar review
processes.
In summary, we believe the Navy's methods, including the underlying
NAEMO modeling and the method for incorporating mitigation and
avoidance, are the most appropriate methods for predicting non-auditory
injury, PTS, TTS, and behavioral disturbance. But even with the
consideration of mitigation and avoidance, given some of the more
conservative components of the methodology (e.g., the thresholds do not
consider ear recovery between pulses), we would describe the
application of these methods as identifying the maximum number of
[[Page 49719]]
instances in which marine mammals would be reasonably expected to be
taken through non-auditory injury, PTS, TTS, or behavioral disturbance.
Summary of Requested Take From Training Activities
Based on the methods discussed in the previous sections and the
Navy's model and quantitative assessment of mitigation, the Navy
provided its take estimate and request for authorization of takes
incidental to the use of acoustic and explosive sources for training
activities both annually (based on the maximum number of activities
that could occur per 12-month period) and over the 7-year period
covered by the Navy's rulemaking/LOA application. The following
species/stocks present in the TMAA were modeled by the Navy and
estimated to have 0 takes of any type from any activity source: Western
North Pacific stock of humpback whale; Eastern North Pacific and
Western North Pacific stocks of gray whales; Eastern North Pacific
Alaska Resident and AT1 Transient stocks of killer whales; Gulf of
Alaska and Southeast Alaska stocks of harbor porpoises; U.S. stock of
California sea lion; Eastern U.S. and Western U.S. stock of Steller sea
lion; Cook Inlet/Shelikof Strait, North Kodiak, Prince William Sound,
and South Kodiak stocks of harbor seals, and Alaska stock of Ribbon
seals.
The Phase II rule (82 FR 19530; April 26, 2017), valid from April
2017 to April 2022, authorized Level B harassment take of the Eastern
North Pacific Alaska Resident stock of killer whales, Gulf of Alaska
and Southeast Alaska stocks of harbor porpoise, California sea lion,
Eastern U.S. and Western U.S. stock of Steller sea lion, and South
Kodiak and Prince William Sound stocks of harbor seal. Takes of these
stocks in Phase II were all expected to occur as a result of exposure
to sonar activity, rather than explosive use. Inclusion of new density/
distribution information and updated BRFs and corresponding cut-offs
resulted in 0 estimated takes for these species and stocks in this
rulemaking for Phase III.
NMFS has reviewed the Navy's data, methodology, and analysis for
the current phase of rulemaking (Phase III) and determined that it is
complete and accurate. However, NMFS has conservatively proposed to
include incidental take of the Western North Pacific stock of humpback
whale and Eastern North Pacific stock of gray whale, for the following
reasons. For the Western North Pacific stock of humpback whale, in
calculating takes by Level B harassment from sonar in Phase III, the
application of the Phase III BRFs with corresponding cut-offs (20 km
for mysticetes), in addition to the stock guild breakout which assigns
0.05 percent of the take of humpback whales to the Western North
Pacific stock, generated a near-zero result, which the Navy rounded to
zero in its rulemaking/LOA application. However, NMFS authorized take
of one Western North Pacific humpback whale in the Phase II LOA, and,
given that they do occur in the area, NMFS is conservatively proposing
to authorize take by Level B harassment of one group (3 animals)
annually in this Phase III rulemaking. The annual take estimate of 3
animals reflects the average group size of on and off-effort survey
sightings of humpback whales reported in Rone et al. (2017). For the
Eastern North Pacific stock of gray whales, application of the Phase
III BRFs with corresponding cut-offs (20 km for mysticetes) resulted in
true zero takes by Level B harassment for Phase III. However, Palacios
et al. (2021) reported locations of three tagged gray whales within the
TMAA as well as tracks of two additional gray whales that crossed the
TMAA, and as noted previously, the TMAA overlaps with the gray whale
migratory corridor BIA (November-January, southbound; March-May,
northbound). As such, NMFS is conservatively proposing to authorize
take by Level B harassment of one group (4 animals) of Eastern North
Pacific gray whales annually in this Phase III rulemaking. The annual
take estimate of 4 animals reflects the average group sizes of on and
off-effort survey sightings of gray whales (excluding an outlier of an
estimated 25 gray whales in one group) reported in Rone et al. (2017).
For all other species and stocks, NMFS agrees that the estimates
for incidental takes by harassment from all sources requested for
authorization are the maximum number of instances in which marine
mammals are reasonably expected to be taken. NMFS also agrees that no
mortality or serious injury is anticipated to occur, and no lethal take
is proposed to be authorized.
Estimated Harassment Take From Training Activities
For the Navy's training activities, Table 30 summarizes the Navy's
take estimate and request and the maximum annual and 7-year total
amount and type of Level A harassment and Level B harassment for the 7-
year period that NMFS anticipates is reasonably likely to occur
(including the incidental take of Western North Pacific stock of
humpback whale and Eastern North Pacific stock of gray whale, discussed
above) by species and stock. Note that take by Level B harassment
includes both behavioral disruption and TTS. Tables 6-10 through 6-24
(sonar and other transducers) and 6-41 through 6-49 (explosives) in
Section 6 of the Navy's rulemaking/LOA application provide the
comparative amounts of TTS and behavioral disruption for each species
and stock annually, noting that if a modeled marine mammal was
``taken'' through exposure to both TTS and behavioral disruption in the
model, it was recorded as a TTS.
Table 30--Annual and 7-Year Total Species/Stock-Specific Take Estimates Proposed for Authorization From Acoustic and Explosive Sound Source Effects for
All Training Activities in the TMAA
--------------------------------------------------------------------------------------------------------------------------------------------------------
Annual 7-year total
Species Stock ---------------------------------------------------------------
Level B Level A Level B Level A
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetacea
Suborder Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae (right whales):
North Pacific right whale *................ Eastern North Pacific.................. 3 0 21 0
Family Balaenopteridae (rorquals):
Humpback whale............................. California, Oregon, & Washington *..... 10 0 70 0
Central North Pacific *................ 79 0 553 0
Western North Pacific *................ \a\ 3 0 \a\ 21 0
Blue whale *............................... Central North Pacific.................. 3 0 21 0
Eastern North Pacific.................. 36 0 252 0
Fin whale *................................ Northeast Pacific...................... 1,242 2 8,694 14
[[Page 49720]]
Sei whale *................................ Eastern North Pacific.................. 37 0 259 0
Minke whale................................ Alaska................................. 50 0 350 0
Family Eschrichtiidae (gray whale):
Gray whale................................. Eastern North Pacific.................. \a\ 4 0 \a\ 28 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Suborder Odontoceti (toothed whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae (dolphins):
Killer whale............................... Eastern North Pacific, Offshore........ 81 0 567 0
Gulf of Alaska, Aleutian Island, & 143 0 1,001 0
Bering Sea Transient.
Pacific white-sided dolphin................ North Pacific.......................... 1,574 0 11,018 0
Family Phocoenidae (porpoises):
Dall's porpoise............................ Alaska................................. 9,287 64 65,009 448
Family Physeteridae (sperm whale):
Sperm whale *.............................. North Pacific.......................... 112 0 784 0
Family Ziphiidae (beaked whales):
Baird's beaked whale....................... Alaska................................. 106 0 742 0
Cuvier's beaked whale...................... Alaska................................. 433 0 3,031 0
Stejneger's beaked whale................... Alaska................................. 482 0 3,374 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora
Suborder Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otarridae:
Northern fur seal.......................... Eastern Pacific........................ 3,003 0 21,021 0
California............................. 61 0 427 0
Family Phocidae (true seals):
Northern elephant seal..................... California............................. 2,547 8 17,829 56
--------------------------------------------------------------------------------------------------------------------------------------------------------
* ESA-listed species and stocks within the GOA Study Area.
\a\ The Navy's Acoustic Effects Model estimated zero takes for each of these stocks. However, NMFS conservatively proposes to authorize take by Level B
harassment of one group of Western North Pacific humpback whale and one group of Eastern North Pacific gray whale. The annual take estimates reflect
the average group sizes of on and off-effort survey sightings of humpback whale and gray whale (excluding an outlier of an estimated 25 gray whales in
one group) reported in Rone et al. (2017).
Proposed Mitigation Measures
Under section 101(a)(5)(A) of the MMPA, NMFS must set forth the
permissible methods of taking pursuant to the activity, and other means
of effecting the least practicable adverse impact on the species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance, and on the
availability of the species or stocks for subsistence uses (``least
practicable adverse impact''). NMFS does not have a regulatory
definition for least practicable adverse impact. The 2004 NDAA amended
the MMPA as it relates to military readiness activities and the
incidental take authorization process such that a determination of
``least practicable adverse impact'' shall include consideration of
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
In Conservation Council for Hawaii v. National Marine Fisheries
Service, 97 F. Supp. 3d 1210, 1229 (D. Haw. 2015), the Court stated
that NMFS ``appear[s] to think [it] satisf[ies] the statutory `least
practicable adverse impact' requirement with a `negligible impact'
finding.'' In 2016, expressing similar concerns in a challenge to a
U.S. Navy Surveillance Towed Array Sensor System Low Frequency Active
Sonar (SURTASS LFA) incidental take rule (77 FR 50290), the Ninth
Circuit Court of Appeals in Natural Resources Defense Council (NRDC) v.
Pritzker, 828 F.3d 1125, 1134 (9th Cir. 2016), stated ``[c]ompliance
with the `negligible impact' requirement does not mean there [is]
compliance with the `least practicable adverse impact' standard.'' As
the Ninth Circuit noted in its opinion, however, the Court was
interpreting the statute without the benefit of NMFS' formal
interpretation. We state here explicitly that NMFS is in full agreement
that the ``negligible impact'' and ``least practicable adverse impact''
requirements are distinct, even though both statutory standards refer
to species and stocks. With that in mind, we provide further
explanation of our interpretation of least practicable adverse impact,
and explain what distinguishes it from the negligible impact standard.
This discussion is consistent with previous rules we have published,
such as the Navy's HSTT rule (83 FR 66846; December 27, 2018), AFTT
rule (84 FR 70712; December 23, 2019), Mariana Islands Training and
Testing (MITT) rule (85 FR 46302; July 31, 2020), and the Northwest
Training and Testing (NWTT) rule (85 FR 72312; November 12, 2020).
Before NMFS can issue incidental take regulations under section
101(a)(5)(A) of the MMPA, it must make a finding that the total taking
will have a ``negligible impact'' on the affected ``species or stocks''
of marine mammals. NMFS' and U.S. Fish and Wildlife Service's
implementing regulations for section 101(a)(5) both define ``negligible
impact'' as an impact resulting from the specified activity that cannot
be reasonably expected to, and is not reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival (50 CFR 216.103 and 50 CFR 18.27(c)).
Recruitment (i.e., reproduction) and survival rates are used to
determine
[[Page 49721]]
population growth rates \2\ and, therefore are considered in evaluating
population level impacts.
---------------------------------------------------------------------------
\2\ A growth rate can be positive, negative, or flat.
---------------------------------------------------------------------------
As stated in the preamble to the proposed rule for the MMPA
incidental take implementing regulations (53 FR 8473; March 15, 1988),
not every population-level impact violates the negligible impact
requirement. The negligible impact standard does not require a finding
that the anticipated take will have ``no effect'' on population numbers
or growth rates: the statutory standard does not require that the same
recovery rate be maintained, rather it requires that no significant
effect on annual rates of recruitment or survival occurs. The key
factor is the significance of the level of impact on rates of
recruitment or survival. (54 FR 40338, 40341-42; September 29, 1989).
While some level of impact on population numbers or growth rates of
a species or stock may occur and still satisfy the negligible impact
requirement--even without consideration of mitigation--the least
practicable adverse impact provision separately requires NMFS to
prescribe means of effecting the least practicable adverse impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance (50 CFR
216.102(b)), which are typically identified as the subject of
mitigation measures.\3\
---------------------------------------------------------------------------
\3\ Separately, NMFS also must prescribe means of effecting the
least practicable adverse impact on the availability of the species
or stocks for subsistence uses, when applicable. See the Subsistence
Harvest of Marine Mammals section for separate discussion of the
effects of the specified activities on Alaska Native subsistence
use.
---------------------------------------------------------------------------
The negligible impact and least practicable adverse impact
standards in the MMPA both call for evaluation at the level of the
``species or stock.'' The MMPA does not define the term ``species.''
However, Merriam-Webster Dictionary defines ``species'' to include
``related organisms or populations potentially capable of
interbreeding.'' See www.merriam-webster.com/dictionary/species
(emphasis added). Section 3(11) of the MMPA defines ``stock'' as a
group of marine mammals of the same species or smaller taxa in a common
spatial arrangement that interbreed when mature. The definition of
``population'' is a group of interbreeding organisms that represents
the level of organization at which speciation begins. www.merriam-webster.com/dictionary/population. The definition of ``population'' is
strikingly similar to the MMPA's definition of ``stock,'' with both
involving groups of individuals that belong to the same species and are
located in a manner that allows for interbreeding. In fact, under MMPA
section 3(11), the statutory term ``stock'' in the MMPA is
interchangeable with the statutory term ``population stock.'' Both the
negligible impact standard and the least practicable adverse impact
standard call for evaluation at the level of the species or stock, and
the terms ``species'' and ``stock'' both relate to populations;
therefore, it is appropriate to view both the negligible impact
standard and the least practicable adverse impact standard as having a
population-level focus.
This interpretation is consistent with Congress' statutory findings
for enacting the MMPA, nearly all of which are most applicable at the
species or stock (i.e., population) level. See MMPA section 2 (finding
that it is species and population stocks that are or may be in danger
of extinction or depletion; that it is species and population stocks
that should not diminish beyond being significant functioning elements
of their ecosystems; and that it is species and population stocks that
should not be permitted to diminish below their optimum sustainable
population level). Annual rates of recruitment (i.e., reproduction) and
survival are the key biological metrics used in the evaluation of
population-level impacts, and accordingly these same metrics are also
used in the evaluation of population level impacts for the least
practicable adverse impact standard.
Recognizing this common focus of the least practicable adverse
impact and negligible impact provisions on the ``species or stock''
does not mean we conflate the two standards; despite some common
statutory language, we recognize the two provisions are different and
have different functions. First, a negligible impact finding is
required before NMFS can issue an incidental take authorization.
Although it is acceptable to use the mitigation measures to reach a
negligible impact finding (see 50 CFR 216.104(c)), no amount of
mitigation can enable NMFS to issue an incidental take authorization
for an activity that still would not meet the negligible impact
standard. Moreover, even where NMFS can reach a negligible impact
finding--which we emphasize does allow for the possibility of some
``negligible'' population-level impact--the agency must still prescribe
measures that will affect the least practicable amount of adverse
impact upon the affected species or stock.
Section 101(a)(5)(A)(i)(II) requires NMFS to issue, in conjunction
with its authorization, binding--and enforceable--restrictions (in the
form of regulations) setting forth how the activity must be conducted,
thus ensuring the activity has the ``least practicable adverse impact''
on the affected species or stocks. In situations where mitigation is
specifically needed to reach a negligible impact determination, section
101(a)(5)(A)(i)(II) also provides a mechanism for ensuring compliance
with the ``negligible impact'' requirement. Finally, the least
practicable adverse impact standard also requires consideration of
measures for marine mammal habitat, with particular attention to
rookeries, mating grounds, and other areas of similar significance, and
for subsistence impacts, whereas the negligible impact standard is
concerned solely with conclusions about the impact of an activity on
annual rates of recruitment and survival.\4\ In NRDC v. Pritzker, the
Court stated, ``[t]he statute is properly read to mean that even if
population levels are not threatened significantly, still the agency
must adopt mitigation measures aimed at protecting marine mammals to
the greatest extent practicable in light of military readiness needs.''
Pritzker at 1134 (emphases added). This statement is consistent with
our understanding stated above that even when the effects of an action
satisfy the negligible impact standard (i.e., in the Court's words,
``population levels are not threatened significantly''), still the
agency must prescribe mitigation under the least practicable adverse
impact standard. However, as the statute indicates, the focus of both
standards is ultimately the impact on the affected ``species or
stock,'' and not solely focused on or directed at the impact on
individual marine mammals.
---------------------------------------------------------------------------
\4\ Outside of the military readiness context, mitigation may
also be appropriate to ensure compliance with the ``small numbers''
language in MMPA sections 101(a)(5)(A) and (D).
---------------------------------------------------------------------------
We have carefully reviewed and considered the Ninth Circuit's
opinion in NRDC v. Pritzker in its entirety. While the Court's
reference to ``marine mammals'' rather than ``marine mammal species or
stocks'' in the italicized language above might be construed as holding
that the least practicable adverse impact standard applies at the
individual ``marine mammal'' level, i.e., that NMFS must require
mitigation to minimize impacts to each individual marine mammal unless
impracticable, we believe such an interpretation reflects an incomplete
appreciation of the Court's holding. In our view, the opinion as a
whole turned on the Court's determination that NMFS had not given
separate and independent
[[Page 49722]]
meaning to the least practicable adverse impact standard apart from the
negligible impact standard, and further, that the Court's use of the
term ``marine mammals'' was not addressing the question of whether the
standard applies to individual animals as opposed to the species or
stock as a whole. We recognize that, while consideration of mitigation
can play a role in a negligible impact determination, consideration of
mitigation measures extends beyond that analysis. In evaluating what
mitigation measures are appropriate, NMFS considers the potential
impacts of the specified activities, the availability of measures to
minimize those potential impacts, and the practicability of
implementing those measures, as we describe below.
Implementation of Least Practicable Adverse Impact Standard
Given the NRDC v. Pritzker decision, we discuss here how we
determine whether a measure or set of measures meets the ``least
practicable adverse impact'' standard. Our separate analysis of whether
the take anticipated to result from Navy's activities meets the
``negligible impact'' standard appears in the Preliminary Analysis and
Negligible Impact Determination section below.
Our evaluation of potential mitigation measures includes
consideration of two primary factors:
(1) The manner in which, and the degree to which, implementation of
the potential measure(s) is expected to reduce adverse impacts to
marine mammal species or stocks, their habitat, or their availability
for subsistence uses (where relevant). This analysis considers such
things as the nature of the potential adverse impact (such as
likelihood, scope, and range), the likelihood that the measure will be
effective if implemented, and the likelihood of successful
implementation; and
(2) The practicability of the measure(s) for applicant
implementation. Practicability of implementation may consider such
things as cost, impact on activities, and, in the case of a military
readiness activity, specifically considers personnel safety,
practicality of implementation, and impact on the effectiveness of the
military readiness activity.
While the language of the least practicable adverse impact standard
calls for minimizing impacts to affected species or stocks, we
recognize that the reduction of impacts to those species or stocks
accrues through the application of mitigation measures that limit
impacts to individual animals. Accordingly, NMFS' analysis focuses on
measures that are designed to avoid or minimize impacts on individual
marine mammals that are likely to increase the probability or severity
of population-level effects.
While direct evidence of impacts to species or stocks from a
specified activity is rarely available, and additional study is still
needed to understand how specific disturbance events affect the fitness
of individuals of certain species, there have been improvements in
understanding the process by which disturbance effects are translated
to the population. With recent scientific advancements (both marine
mammal energetic research and the development of energetic frameworks),
the relative likelihood or degree of impacts on species or stocks may
often be inferred given a detailed understanding of the activity, the
environment, and the affected species or stocks--and the best available
science has been used here. This same information is used in the
development of mitigation measures and helps us understand how
mitigation measures contribute to lessening effects (or the risk
thereof) to species or stocks. We also acknowledge that there is always
the potential that new information, or a new recommendation, could
become available in the future and necessitate reevaluation of
mitigation measures (which may be addressed through adaptive
management) to see if further reductions of population impacts are
possible and practicable.
In the evaluation of specific measures, the details of the
specified activity will necessarily inform each of the two primary
factors discussed above (expected reduction of impacts and
practicability), and are carefully considered to determine the types of
mitigation that are appropriate under the least practicable adverse
impact standard. Analysis of how a potential mitigation measure may
reduce adverse impacts on a marine mammal stock or species,
consideration of personnel safety, practicality of implementation, and
consideration of the impact on effectiveness of military readiness
activities are not issues that can be meaningfully evaluated through a
yes/no lens. The manner in which, and the degree to which,
implementation of a measure is expected to reduce impacts, as well as
its practicability in terms of these considerations, can vary widely.
For example, a time/area restriction could be of very high value for
decreasing population-level impacts (e.g., avoiding disturbance of
feeding females in an area of established biological importance) or it
could be of lower value (e.g., decreased disturbance in an area of high
productivity but of less biological importance). Regarding
practicability, a measure might involve restrictions in an area or time
that impede the Navy's ability to certify a strike group (higher impact
on mission effectiveness), or it could mean delaying a small in-port
training event by 30 minutes to avoid exposure of a marine mammal to
injurious levels of sound (lower impact). A responsible evaluation of
``least practicable adverse impact'' will consider the factors along
these realistic scales. Accordingly, the greater the likelihood that a
measure will contribute to reducing the probability or severity of
adverse impacts to the species or stock or its habitat, the greater the
weight that measure is given when considered in combination with
practicability to determine the appropriateness of the mitigation
measure, and vice versa. We discuss consideration of these factors in
greater detail below.
1. Reduction of adverse impacts to marine mammal species or stocks
and their habitat. The emphasis given to a measure's ability to reduce
the impacts on a species or stock considers the degree, likelihood, and
context of the anticipated reduction of impacts to individuals (and how
many individuals) as well as the status of the species or stock.
The ultimate impact on any individual from a disturbance event
(which informs the likelihood of adverse species- or stock-level
effects) is dependent on the circumstances and associated contextual
factors, such as duration of exposure to stressors. Though any proposed
mitigation needs to be evaluated in the context of the specific
activity and the species or stocks affected, measures with the
following types of effects have greater value in reducing the
likelihood or severity of adverse species- or stock-level impacts:
avoiding or minimizing injury or mortality; limiting interruption of
known feeding, breeding, mother/young, or resting behaviors; minimizing
the abandonment of important habitat (temporally and spatially);
minimizing the number of individuals subjected to these types of
disruptions; and limiting degradation of habitat. Mitigating these
types of effects is intended to reduce the likelihood that the activity
will result in energetic or other types of impacts that are more likely
to result in reduced reproductive success or survivorship. It is also
important to consider the degree of impacts that are expected in the
absence of mitigation in order to assess the added value of any
potential
[[Page 49723]]
measures. Finally, because the least practicable adverse impact
standard gives NMFS discretion to weigh a variety of factors when
determining appropriate mitigation measures and because the focus of
the standard is on reducing impacts at the species or stock level, the
least practicable adverse impact standard does not compel mitigation
for every kind of take, or every individual taken, if that mitigation
is unlikely to meaningfully contribute to the reduction of adverse
impacts on the species or stock and its habitat, even when practicable
for implementation by the applicant.
The status of the species or stock is also relevant in evaluating
the appropriateness of potential mitigation measures in the context of
least practicable adverse impact. The following are examples of factors
that may (either alone, or in combination) result in greater emphasis
on the importance of a mitigation measure in reducing impacts on a
species or stock: the stock is known to be decreasing or status is
unknown, but believed to be declining; the known annual mortality (from
any source) is approaching or exceeding the potential biological
removal (PBR) level (as defined in MMPA section 3(20)); the affected
species or stock is a small, resident population; or the stock is
involved in a UME or has other known vulnerabilities, such as
recovering from an oil spill.
Habitat mitigation, particularly as it relates to rookeries, mating
grounds, and areas of similar significance, is also relevant to
achieving the standard and can include measures such as reducing
impacts of the activity on known prey utilized in the activity area or
reducing impacts on physical habitat. As with species- or stock-related
mitigation, the emphasis given to a measure's ability to reduce impacts
on a species or stock's habitat considers the degree, likelihood, and
context of the anticipated reduction of impacts to habitat. Because
habitat value is informed by marine mammal presence and use, in some
cases there may be overlap in measures for the species or stock and for
use of habitat.
We consider available information indicating the likelihood of any
measure to accomplish its objective. If evidence shows that a measure
has not typically been effective nor successful, then either that
measure should be modified or the potential value of the measure to
reduce effects should be lowered.
2. Practicability. Factors considered may include cost, impact on
activities, and, in the case of a military readiness activity, will
include personnel safety, practicality of implementation, and impact on
the effectiveness of the military readiness activity (see MMPA section
101(a)(5)(A)(ii)).
Assessment of Mitigation Measures for the GOA Study Area
NMFS has fully reviewed the specified activities and the mitigation
measures included in the Navy's rulemaking/LOA application, the 2020
GOA DSEIS/OEIS, and the 2022 Supplement to the 2020 GOA DSEIS/OEIS to
determine if the mitigation measures would result in the least
practicable adverse impact on marine mammals and their habitat. NMFS
worked with the Navy in the development of the Navy's initially
proposed measures, which are informed by years of implementation and
monitoring. A complete discussion of the Navy's evaluation process used
to develop, assess, and select mitigation measures, which was informed
by input from NMFS, can be found in Chapter 5 (Mitigation) of the 2020
GOA DSEIS/OEIS. The process described in Chapter 5 (Mitigation) of the
2020 GOA DSEIS/OEIS robustly supported NMFS' independent evaluation of
whether the mitigation measures would meet the least practicable
adverse impact standard, including the addition of the Continental
Shelf and Slope Mitigation Area presented in the February 2022 second
updated application and analyzed in the 2022 Supplement to the 2020 GOA
DSEIS/OEIS. The Navy would be required to implement the mitigation
measures identified in this rule for the full 7 years to avoid or
reduce potential impacts from acoustic and explosive stressors.
As a general matter, where an applicant proposes measures that are
likely to reduce impacts to marine mammals, the fact that they are
included in the application indicates that the measures are
practicable, and it is not necessary for NMFS to conduct a detailed
analysis of the measures the applicant proposed (rather, they are
simply included). However, it is still necessary for NMFS to consider
whether there are additional practicable measures that would
meaningfully reduce the probability or severity of impacts that could
affect reproductive success or survivorship.
Overall the Navy has agreed to procedural mitigation measures that
would reduce the probability and/or severity of impacts expected to
result from acute exposure to acoustic sources or explosives, ship
strike, and impacts to marine mammal habitat. Specifically, the Navy
would use a combination of delayed starts, powerdowns, and shutdowns to
avoid mortality or serious injury, minimize the likelihood or severity
of PTS or other injury, and reduce instances of TTS or more severe
behavioral disruption caused by acoustic sources or explosives. The
Navy would also implement multiple time/area restrictions that would
reduce take of marine mammals in areas or at times where they are known
to engage in important behaviors, such as foraging, where the
disruption of those behaviors would have a higher probability of
resulting in impacts on reproduction or survival of individuals that
could lead to population-level impacts.
The Navy assessed the practicability of the proposed measures in
the context of personnel safety, practicality of implementation, and
their impacts on the Navy's ability to meet their Title 10 requirements
and found that the measures are supportable. As described in more
detail below, NMFS has independently evaluated the measures the Navy
proposed in the manner described earlier in this section (i.e., in
consideration of their ability to reduce adverse impacts on marine
mammal species and their habitat and their practicability for
implementation). We have determined that the measures would
significantly and adequately reduce impacts on the affected marine
mammal species and stocks and their habitat and, further, be
practicable for Navy implementation. Therefore, the mitigation measures
assure that the Navy's activities would have the least practicable
adverse impact on the species or stocks and their habitat.
The Navy also evaluated numerous measures in the 2020 GOA DSEIS/
OEIS that were not included in the Navy's rulemaking/LOA application,
and NMFS independently reviewed and preliminarily concurs with the
Navy's analysis that their inclusion was not appropriate under the
least practicable adverse impact standard based on our assessment. The
Navy considered these additional potential mitigation measures in two
groups. First, Chapter 5 (Mitigation) of the 2020 GOA DSEIS/OEIS, in
the Measures Considered but Eliminated section, includes an analysis of
an array of different types of mitigation that have been recommended
over the years by non-governmental organizations or the public, through
scoping or public comment on environmental compliance documents. As
described in Chapter 5 (Mitigation) of the 2020 GOA DSEIS/OEIS, the
Navy considered reducing its overall amount of training, reducing
explosive use, modifying its sound sources, completely replacing live
training with computer simulation, and including time of day
[[Page 49724]]
restrictions. Many of these mitigation measures could potentially
reduce the number of marine mammals taken, via direct reduction of the
activities or amount of sound energy put in the water. However, as
described in Chapter 5 (Mitigation) of the 2020 GOA DSEIS/OEIS, the
Navy needs to train in the conditions in which it fights--and these
types of modifications fundamentally change the activity in a manner
that would not support the purpose and need for the training (i.e., are
entirely impracticable) and therefore are not considered further. NMFS
finds the Navy's explanation for why adoption of these recommendations
would unacceptably undermine the purpose of the training persuasive.
After independent review, NMFS finds the Navy's judgment on the impacts
of these potential mitigation measures to personnel safety,
practicality of implementation, and the effectiveness of training
persuasive, and for these reasons, NMFS finds that these measures do
not meet the least practicable adverse impact standard because they are
not practicable for implementation in either the TMAA or the GOA Study
Area overall.
Second, in Chapter 5 (Mitigation) of the 2020 GOA DSEIS/OEIS, the
Navy evaluated additional potential procedural mitigation measures,
including increased mitigation zones, ramp-up measures, additional
passive acoustic and visual monitoring, and decreased vessel speeds.
Some of these measures have the potential to incrementally reduce take
to some degree in certain circumstances, though the degree to which
this would occur is typically low or uncertain. However, as described
in the Navy's analysis, the measures would have significant direct
negative effects on mission effectiveness and are considered
impracticable (see Chapter 5, Mitigation, of 2020 GOA DSEIS/OEIS). NMFS
independently reviewed the Navy's evaluation and concurs with this
assessment, which supports NMFS' preliminary findings that the
impracticability of this additional mitigation would greatly outweigh
any potential minor reduction in marine mammal impacts that might
result; therefore, these additional mitigation measures are not
warranted.
Last, Chapter 5 (Mitigation) of the 2020 GOA DSEIS/OEIS, also
describes a comprehensive analysis of potential geographic mitigation
that includes consideration of both a biological assessment of how the
potential time/area limitation would benefit the species and its
habitat (e.g., is a key area of biological importance or would result
in avoidance or reduction of impacts) in the context of the stressors
of concern in the specific area and an operational assessment of the
practicability of implementation (e.g., including an assessment of the
specific importance of an area for training, considering proximity to
training ranges and emergency landing fields and other issues). In its
second updated application and the 2022 Supplement to the 2020 GOA
DSEIS/OEIS, the Navy included an expansion to the mitigation area
previously referred to as the Portlock Bank Mitigation Area, now
referred to as the Continental Shelf and Slope Mitigation Area. The
Navy has found that geographic mitigation beyond what is included in
the 2020 GOA DSEIS/OEIS and 2022 Supplement to the 2020 GOA DSEIS/OEIS
is not warranted because the anticipated reduction of adverse impacts
on marine mammal species and their habitat is not sufficient to offset
the impracticability of implementation. In some cases potential
benefits to marine mammals were non-existent, while in others the
consequences on mission effectiveness were too great.
NMFS has reviewed the Navy's analysis in Chapter 5 (Mitigation) of
the 2020 GOA DSEIS/OEIS and Chapter 5 (Standard Operating Procedures,
Mitigation, and Monitoring) of the 2022 Supplement to the 2020 GOA
DSEIS/OEIS, which consider the same factors that NMFS considers to
satisfy the least practicable adverse impact standard, and concurs with
the analysis and conclusions. Therefore, NMFS is not proposing to
include any of the measures that the Navy ruled out in the 2020 GOA
DSEIS/OEIS. Below are the mitigation measures that NMFS has
preliminarily determined would ensure the least practicable adverse
impact on all affected species and their habitat, including the
specific considerations for military readiness activities. The
following sections describe the mitigation measures that would be
implemented in association with the training activities analyzed in
this document. The mitigation measures are organized into two
categories: procedural mitigation and mitigation areas.
Procedural Mitigation
Procedural mitigation is mitigation that the Navy would implement
whenever and wherever an applicable training activity takes place
within the GOA Study Area. The Navy customizes procedural mitigation
for each applicable activity category or stressor. Procedural
mitigation generally involves: (1) the use of one or more trained
Lookouts to diligently observe for specific biological resources
(including marine mammals) within a mitigation zone, (2) requirements
for Lookouts to immediately communicate sightings of specific
biological resources to the appropriate watch station for information
dissemination, and (3) requirements for the watch station to implement
mitigation (e.g., halt an activity) until certain recommencement
conditions have been met. The first procedural mitigation (Table 31) is
designed to aid Lookouts and other applicable Navy personnel with their
observation, environmental compliance, and reporting responsibilities.
The remainder of the procedural mitigation measures (Table 32 through
Table 39) are organized by stressor type and activity category and
include acoustic stressors (i.e., active sonar, weapons firing noise),
explosive stressors (i.e., large-caliber projectiles, bombs), and
physical disturbance and strike stressors (i.e., vessel movement, towed
in-water devices, small-, medium-, and large-caliber non-explosive
practice munitions, non-explosive bombs).
Table 31--Procedural Mitigation for Environmental Awareness and
Education
------------------------------------------------------------------------
Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
All training activities, as applicable.
Mitigation Requirements:
Appropriate Navy personnel (including civilian personnel)
involved in mitigation and training activity reporting under the
specified activities will complete one or more modules of the U.S.
Navy Afloat Environmental Compliance Training Series, as identified
in their career path training plan. Modules include:
[[Page 49725]]
--Introduction to the U.S. Navy Afloat Environmental Compliance
Training Series. The introductory module provides information
on environmental laws (e.g., Endangered Species Act, Marine
Mammal Protection Act) and the corresponding responsibilities
that are relevant to Navy training activities. The material
explains why environmental compliance is important in
supporting the Navy's commitment to environmental stewardship.
--Marine Species Awareness Training. All bridge watch personnel,
Commanding Officers, Executive Officers, maritime patrol
aircraft aircrews, anti[hyphen]submarine warfare aircrews,
Lookouts, and equivalent civilian personnel must successfully
complete the Marine Species Awareness Training prior to
standing watch or serving as a Lookout. The Marine Species
Awareness Training provides information on sighting cues,
visual observation tools and techniques, and sighting
notification procedures. Navy biologists developed Marine
Species Awareness Training to improve the effectiveness of
visual observations for biological resources, focusing on
marine mammals and sea turtles, and including floating
vegetation, jellyfish aggregations, and flocks of seabirds.
--U.S. Navy Protective Measures Assessment Protocol. This module
provides the necessary instruction for accessing mitigation
requirements during the event planning phase using the
Protective Measures Assessment Protocol software tool.
--U.S. Navy Sonar Positional Reporting System and Marine Mammal
Incident Reporting. This module provides instruction on the
procedures and activity reporting requirements for the Sonar
Positional Reporting System and marine mammal incident
reporting.
------------------------------------------------------------------------
Procedural Mitigation for Acoustic Stressors
Mitigation measures for acoustic stressors are provided in Table 32
and Table 33.
Table 32--Procedural Mitigation for Active Sonar
------------------------------------------------------------------------
Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
Mid-frequency active sonar and high-frequency active sonar:
--For vessel-based active sonar activities, mitigation applies
only to sources that are positively controlled and deployed
from manned surface vessels (e.g., sonar sources towed from
manned surface platforms).
--For aircraft-based active sonar activities, mitigation applies
only to sources that are positively controlled and deployed
from manned aircraft that do not operate at high altitudes
(e.g., rotary-wing aircraft). Mitigation does not apply to
active sonar sources deployed from unmanned aircraft or
aircraft operating at high altitudes (e.g., maritime patrol
aircraft).
Number of Lookouts and Observation Platform:
Hull-mounted sources:
--1 Lookout: Platforms with space or manning restrictions while
underway (at the forward part of a small boat or ship) and
platforms using active sonar while moored or at anchor.
--2 Lookouts: Platforms without space or manning restrictions
while underway (at the forward part of the ship).
Sources that are not hull-mounted:
--1 Lookout on the ship or aircraft conducting the activity.
Mitigation Requirements:
Mitigation zones:
--1,000 yd (914.4 m) power down, 500 yd (457.2 m) power down,
and 200 yd (182.9 m) shut down for hull-mounted mid-frequency
active sonar (see During the activity below).
--200 yd (182.9 m) shut down for mid-frequency active sonar
sources that are not hull-mounted, and high-frequency active
sonar (see During the activity below).
Prior to the initial start of the activity (e.g., when
maneuvering on station):
--Navy personnel will observe the mitigation zone for floating
vegetation and marine mammals; if floating vegetation or a
marine mammal is observed, Navy personnel will relocate or
delay the start of active sonar transmission until the
mitigation zone is clear of floating vegetation or the
Commencement/recommencement conditions in this table are met
for marine mammals.
During the activity:
--Hull-mounted mid-frequency active sonar: Navy personnel will
observe the mitigation zone for marine mammals; Navy personnel
will power down active sonar transmission by 6 dB if a marine
mammal is observed within 1,000 yd (914.4 m) of the sonar
source; Navy personnel will power down active sonar
transmission an additional 4 dB (10 dB total) if a marine
mammal is observed within 500 yd (457.2 m) of the sonar source;
Navy personnel will cease transmission if a marine mammal is
observed within 200 yd (182.9 m) of the sonar source.
--Mid-frequency active sonar sources that are not hull-mounted,
and high-frequency active sonar: Navy personnel will observe
the mitigation zone for marine mammals; Navy personnel will
cease transmission if a marine mammal is observed within 200 yd
(182.9 m) of the sonar source.
Commencement/recommencement conditions after a marine
mammal sighting before or during the activity:
--Navy personnel will allow a sighted marine mammal to leave the
mitigation zone prior to the initial start of the activity (by
delaying the start) or during the activity (by not recommencing
or powering up active sonar transmission) until one of the
following conditions has been met: (1) the animal is observed
exiting the mitigation zone; (2) the animal is thought to have
exited the mitigation zone based on a determination of its
course, speed, and movement relative to the sonar source; (3)
the mitigation zone has been clear from any additional
sightings for 10 minutes for aircraft-deployed sonar sources or
30 minutes for vessel-deployed sonar sources; (4) for mobile
activities, the active sonar source has transited a distance
equal to double that of the mitigation zone size beyond the
location of the last sighting; or (5) for activities using hull-
mounted sonar, the Lookout concludes that dolphins are
deliberately closing in on the ship to ride the ship's bow
wave, and are therefore out of the main transmission axis of
the sonar (and there are no other marine mammal sightings
within the mitigation zone).
------------------------------------------------------------------------
[[Page 49726]]
Table 33--Procedural Mitigation for Weapons Firing Noise
------------------------------------------------------------------------
Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
Weapon firing noise associated with large-caliber gunnery
activities.
Number of Lookouts and Observation Platform:
1 Lookout positioned on the ship conducting the firing
--Depending on the activity, the Lookout could be the same one
described in Procedural Mitigation for Explosive Large-Caliber
Projectiles (Table 34) or Procedural Mitigation for Small-,
Medium-, and Large-Caliber Non-Explosive Practice Munitions
(Table 38).
Mitigation Requirements:
Mitigation zone:
--30[deg] on either side of the firing line out to 70 yd (64 m)
from the muzzle of the weapon being fired.
Prior to the initial start of the activity:
--Navy personnel will observe the mitigation zone for floating
vegetation and marine mammals; if floating vegetation or a
marine mammal is observed, Navy personnel will relocate or
delay the start of weapon firing until the mitigation zone is
clear of floating vegetation or the Commencement/recommencement
conditions in this table are met for marine mammals.
During the activity:
--Navy personnel will observe the mitigation zone for marine
mammals; if a marine mammal is observed, Navy personnel will
cease weapon firing.
Commencement/recommencement conditions after a marine
mammal sighting before or during the activity:
--Navy personnel will allow a sighted marine mammal to leave the
mitigation zone prior to the initial start of the activity (by
delaying the start) or during the activity (by not recommencing
weapon firing) until one of the following conditions has been
met: (1) the animal is observed exiting the mitigation zone;
(2) the animal is thought to have exited the mitigation zone
based on a determination of its course, speed, and movement
relative to the firing ship; (3) the mitigation zone has been
clear from any additional sightings for 30 minutes; or (4) for
mobile activities, the firing ship has transited a distance
equal to double that of the mitigation zone size beyond the
location of the last sighting.
------------------------------------------------------------------------
Procedural Mitigation for Explosive Stressors
Mitigation measures for explosive stressors are provided in Table
34 and Table 35.
Table 34--Procedural Mitigation for Explosive Large-Caliber Projectiles
------------------------------------------------------------------------
Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
Gunnery activities using explosive large-caliber
projectiles.
--Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
1 Lookout on the vessel or aircraft conducting the
activity.
--Depending on the activity, the Lookout could be the same as
the one described for Procedural Mitigation for Weapons Firing
Noise in Table 33.
If additional platforms are participating in the activity,
Navy personnel positioned in those assets (e.g., safety observers,
evaluators) will support observing the mitigation zone for marine
mammals while performing their regular duties.
Mitigation Requirements:
Mitigation zones:
--1,000 yd (914.4 m) around the intended impact location.
Prior to the initial start of the activity (e.g., when
maneuvering on station):
--Navy personnel will observe the mitigation zone for floating
vegetation and marine mammals; if floating vegetation or a
marine mammal is observed, Navy personnel will relocate or
delay the start of firing until the mitigation zone is clear of
floating vegetation or the Commencement/recommencement
conditions in this table are met for marine mammals.
During the activity:
--Navy personnel will observe the mitigation zone for marine
mammals; if a marine mammal is observed, Navy personnel will
cease firing.
Commencement/recommencement conditions after a marine
mammal sighting before or during the activity:
--Navy personnel will allow a sighted marine mammal to leave the
mitigation zone prior to the initial start of the activity (by
delaying the start) or during the activity (by not recommencing
firing) until one of the following conditions has been met: (1)
the animal is observed exiting the mitigation zone; (2) the
animal is thought to have exited the mitigation zone based on a
determination of its course, speed, and movement relative to
the intended impact location; (3) the mitigation zone has been
clear from any additional sightings for 30 minutes; or (4) for
activities using mobile targets, the intended impact location
has transited a distance equal to double that of the mitigation
zone size beyond the location of the last sighting.
After completion of the activity (e.g., prior to
maneuvering off station):
--Navy personnel will, when practical (e.g., when platforms are
not constrained by fuel restrictions or mission-essential
follow-on commitments), observe the vicinity of where
detonations occurred; if any injured or dead marine mammals are
observed, Navy personnel will follow established incident
reporting procedures.
--If additional platforms are supporting this activity (e.g.,
providing range clearance), Navy personnel positioned on these
assets will assist in the visual observation of the area where
detonations occurred.
------------------------------------------------------------------------
[[Page 49727]]
Table 35--Procedural Mitigation for Explosive Bombs
------------------------------------------------------------------------
Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
Explosive bombs.
Number of Lookouts and Observation Platform:
1 Lookout positioned in the aircraft conducting the
activity.
If additional platforms are participating in the activity,
Navy personnel positioned in those assets (e.g., safety observers,
evaluators) will support observing the mitigation zone for marine
mammals while performing their regular duties.
Mitigation Requirements:
Mitigation zone:
--2,500 yd (2,286 m) around the intended target.
Prior to the initial start of the activity (e.g., when
arriving on station):
--Navy personnel will observe the mitigation zone for floating
vegetation and marine mammals; if floating vegetation or a
marine mammal is observed, Navy personnel will relocate or
delay the start of bomb deployment until the mitigation zone is
clear of floating vegetation or the Commencement/recommencement
conditions in this table are met for marine mammals.
During the activity (e.g., during target approach):
--Navy personnel will observe the mitigation zone for marine
mammals; if a marine mammal is observed, Navy personnel will
cease bomb deployment.
Commencement/recommencement conditions after a marine
mammal sighting before or during the activity:
--Navy personnel will allow a sighted marine mammal to leave the
mitigation zone prior to the initial start of the activity (by
delaying the start) or during the activity (by not recommencing
bomb deployment) until one of the following conditions has been
met: (1) the animal is observed exiting the mitigation zone;
(2) the animal is thought to have exited the mitigation zone
based on a determination of its course, speed, and movement
relative to the intended target; (3) the mitigation zone has
been clear from any additional sightings for 10 minutes; or (4)
for activities using mobile targets, the intended target has
transited a distance equal to double that of the mitigation
zone size beyond the location of the last sighting.
After completion of the activity (e.g., prior to
maneuvering off station):
--Navy personnel will, when practical (e.g., when platforms are
not constrained by fuel restrictions or mission-essential
follow-on commitments), observe for marine mammals in the
vicinity of where detonations occurred; if any injured or dead
marine mammals are observed, Navy personnel will follow
established incident reporting procedures.
--If additional platforms are supporting this activity (e.g.,
providing range clearance), Navy personnel positioned on these
assets will assist in the visual observation of the area where
detonations occurred.
------------------------------------------------------------------------
Procedural Mitigation for Physical Disturbance and Strike Stressors
Mitigation measures for physical disturbance and strike stressors
are provided in Table 36 through Table 39.
Table 36--Procedural Mitigation for Vessel Movement
------------------------------------------------------------------------
Procedural Mitigation Description
-------------------------------------------------------------------------
Stressor or Activity:
Vessel movement
--The mitigation will not be applied if (1) the vessel's safety
is threatened, (2) the vessel is restricted in its ability to
maneuver (e.g., during launching and recovery of aircraft or
landing craft, during towing activities, when mooring), (3) the
vessel is submerged or operated autonomously, or (4) when
impractical based on mission requirements (e.g., during Vessel
Visit, Board, Search, and Seizure activities as military
personnel from ships or aircraft board suspect vessels).
Number of Lookouts and Observation Platform:
1 or more Lookouts on the underway vessel
If additional watch personnel are positioned on underway
vessels, those personnel (e.g., persons assisting with navigation
or safety) will support observing for marine mammals while
performing their regular duties.
Mitigation Requirements:
Mitigation zones:
--500 yd (457.2 m) around the vessel for whales.
--200 yd (182.9 m) around the vessel for marine mammals other
than whales (except those intentionally swimming alongside or
closing in to swim alongside vessels, such as bow-riding or
wake-riding dolphins).
When Underway:
--Navy personnel will observe the direct path of the vessel and
waters surrounding the vessel for marine mammals.
--If a marine mammal is observed in the direct path of the
vessel, Navy personnel will maneuver the vessel as necessary to
maintain the appropriate mitigation zone distance.
--If a marine mammal is observed within waters surrounding the
vessel, Navy personnel will maintain situational awareness of
that animal's position. Based on the animal's course and speed
relative to the vessel's path, Navy personnel will maneuver the
vessel as necessary to ensure that the appropriate mitigation
zone distance from the animal continues to be maintained.
Additional requirements:
--If a marine mammal vessel strike occurs, Navy personnel will
follow established incident reporting procedures.
------------------------------------------------------------------------
[[Page 49728]]
Table 37--Procedural Mitigation for Towed In-Water Devices
------------------------------------------------------------------------
Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
Towed in-water devices
--Mitigation applies to devices that are towed from a manned
surface platform or manned aircraft, or when a manned support
craft is already participating in an activity involving in-
water devices being towed by unmanned platforms.
--The mitigation will not be applied if the safety of the towing
platform or in-water device is threatened.
Number of Lookouts and Observation Platform:
1 Lookout positioned on the towing platform or support
craft.
Mitigation Requirements:
Mitigation zones:
--250 yd (228.6 m) around the towed in-water device for marine
mammals (except those intentionally swimming alongside or
choosing to swim alongside towing vessels, such as bow-riding
or wake-riding dolphins)
During the activity (i.e., when towing an in-water device)
--Navy personnel will observe the mitigation zone for marine
mammals; if a marine mammal is observed, Navy personnel will
maneuver to maintain distance.
------------------------------------------------------------------------
Table 38--Procedural Mitigation for Small-, Medium-, and Large-Caliber
Non-Explosive Practice Munitions
------------------------------------------------------------------------
Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
Gunnery activities using small-, medium-, and large-caliber
non-explosive practice munitions
--Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
1 Lookout positioned on the platform conducting the
activity.
--Depending on the activity, the Lookout could be the same as
the one described in Procedural Mitigation for Weapons Firing
Noise (Table 33).
Mitigation Requirements:
Mitigation zone:
--200 yd (182.9 m) around the intended impact location
Prior to the initial start of the activity (e.g., when
maneuvering on station):
--Navy personnel will observe the mitigation zone for floating
vegetation and marine mammals; if floating vegetation or a
marine mammal is observed, Navy personnel will relocate or
delay the start of firing until the mitigation zone is clear of
floating vegetation or the Commencement/recommencement
conditions in this table are met for marine mammals.
During the activity:
--Navy personnel will observe the mitigation zone for marine
mammals; if a marine mammal is observed, Navy personnel will
cease firing.
Commencement/recommencement conditions after a marine
mammal, sighting before or during the activity:
--Navy personnel will allow a sighted marine mammal to leave the
mitigation zone prior to the initial start of the activity (by
delaying the start) or during the activity (by not recommencing
firing) until one of the following conditions has been met: (1)
the animal is observed exiting the mitigation zone; (2) the
animal is thought to have exited the mitigation zone based on a
determination of its course, speed, and movement relative to
the intended impact location; (3) the mitigation zone has been
clear from any additional sightings for 10 minutes for aircraft-
based firing or 30 minutes for vessel-based firing; or (4) for
activities using a mobile target, the intended impact location
has transited a distance equal to double that of the mitigation
zone size beyond the location of the last sighting.
------------------------------------------------------------------------
Table 39--Procedural Mitigation for Non-Explosive Bombs
------------------------------------------------------------------------
Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
Non-explosive bombs.
Number of Lookouts and Observation Platform:
1 Lookout positioned in an aircraft.
Mitigation Requirements:
Mitigation zone:
--1,000 yd (914.4 m) around the intended target.
Prior to the initial start of the activity (e.g., when
arriving on station):
--Navy personnel will observe the mitigation zone for floating
vegetation and marine mammals; if floating vegetation or a
marine mammal is observed, Navy personnel will relocate or
delay the start of bomb deployment until the mitigation zone is
clear of floating vegetation or the Commencement/recommencement
conditions in this table are met for marine mammals.
During the activity (e.g., during approach of the target):
--Navy personnel will observe the mitigation zone for marine
mammals; if a marine mammal is observed, Navy personnel will
cease bomb deployment.
Commencement/recommencement conditions after a marine
mammal sighting prior to or during the activity:
--Navy personnel will allow a sighted marine mammal to leave the
mitigation zone prior to the initial start of the activity (by
delaying the start) or during the activity (by not recommencing
bomb deployment) until one of the following conditions has been
met: (1) the animal is observed exiting the mitigation zone;
(2) the animal is thought to have exited the mitigation zone
based on a determination of its course, speed, and movement
relative to the intended target; (3) the mitigation zone has
been clear from any additional sightings for 10 minutes; or (4)
for activities using mobile targets, the intended target has
transited a distance equal to double that of the mitigation
zone size beyond the location of the last sighting.
------------------------------------------------------------------------
[[Page 49729]]
Mitigation Areas
In addition to procedural mitigation, the Navy would implement
mitigation measures within mitigation areas to avoid or minimize
potential impacts on marine mammals. The Navy took into account the
best available science and the practicability of implementing
additional mitigation measures, and has enhanced its mitigation
measures beyond those that were included in the 2017-2022 regulations
to further reduce impacts to marine mammals.
Information on the mitigation measures that the Navy would
implement within mitigation areas is provided in Table 40 (see below).
NMFS conducted an independent analysis of the mitigation areas that
the Navy proposed, which are described below. NMFS preliminarily
concurs with the Navy's analysis, which indicates that the measures in
these mitigation areas are both practicable and would reduce the
likelihood or severity of adverse impacts to marine mammal species or
their habitat in the manner described in the Navy's analysis and this
rule. NMFS is heavily reliant on the Navy's description of operational
practicability, since the Navy is best equipped to describe the degree
to which a given mitigation measure affects personnel safety or mission
effectiveness, and is practical to implement. The Navy considers the
measures in this proposed rule to be practicable, and NMFS concurs. We
further discuss the manner in which the Geographic Mitigation Areas in
the proposed rule would reduce the likelihood or severity of adverse
impacts to marine mammal species or their habitat in the Preliminary
Analysis and Negligible Impact Determination section.
Table 40--Geographic Mitigation Areas for Marine Mammals in the GOA
Study Area
------------------------------------------------------------------------
Mitigation area description
-------------------------------------------------------------------------
Stressor or Activity:
Sonar.
Explosives.
Physical disturbance and strikes.
Mitigation Requirements: \1\
North Pacific Right Whale Mitigation Area.
--From June 1-September 30 within the North Pacific Right Whale
Mitigation Area, Navy personnel will not use surface ship hull-
mounted MF1 mid-frequency active sonar during training.
Continental Shelf and Slope Mitigation Area.
--Navy personnel will not detonate explosives below 10,000 ft.
altitude (including at the water surface) in the Continental
Shelf and Slope Mitigation Area during training.
Pre-event Awareness Notifications in the Temporary Maritime
Activities Area.
--The Navy will issue pre-event awareness messages to alert
vessels and aircraft participating in training activities
within the TMAA to the possible presence of concentrations of
large whales on the continental shelf and slope. Occurrences of
large whales may be higher over the continental shelf and slope
relative to other areas of the TMAA. Large whale species in the
TMAA include, but are not limited to, fin whale, blue whale,
humpback whale, gray whale, North Pacific right whale, sei
whale, and sperm whale. To maintain safety of navigation and to
avoid interactions with marine mammals, the Navy will instruct
personnel to remain vigilant to the presence of large whales
that may be vulnerable to vessel strikes or potential impacts
from training activities. Additionally, Navy personnel will use
the information from the awareness notification messages to
assist their visual observation of applicable mitigation zones
during training activities and to aid in the implementation of
procedural mitigation.
------------------------------------------------------------------------
\1\ Should national security present a requirement to conduct training
prohibited by the mitigation requirements specified in this table,
naval units will obtain permission from the designated Command, U.S.
Third Fleet Command Authority, prior to commencement of the activity.
The Navy will provide NMFS with advance notification and include
relevant information about the event (e.g., sonar hours, use of
explosives detonated below 10,000 ft altitude (including at the water
surface) in its annual activity reports to NMFS.
BILLING CODE 3510-22-P
[[Page 49730]]
[GRAPHIC] [TIFF OMITTED] TP11AU22.004
BILLING CODE 3510-22-C
North Pacific Right Whale Mitigation Area
Mitigation within the North Pacific Right Whale Mitigation Area is
primarily designed to avoid or further reduce potential impacts to
North Pacific right whales within important feeding habitat. The
mitigation area fully encompasses the portion of the BIA identified by
Ferguson et al. (2015) for North Pacific right whale feeding that
overlaps the GOA Study Area (overlap between the GOA Study Area and the
BIA occurs in the TMAA only) (Figure 2). North Pacific right whales are
thought to occur in the highest densities in the BIA from June to
September. The Navy would not use surface ship hull-mounted MF1 mid-
frequency active sonar in the mitigation area from June 1 to September
30, as was also required in the Phase II (2017-2022) rule. The North
Pacific Right Whale Mitigation Area is fully within the boundary of the
Continental Shelf and Slope Mitigation Area, discussed below.
Therefore, the mitigation requirements in that area also apply to the
North Pacific Right Whale
[[Page 49731]]
Mitigation Area. While the potential occurrence of North Pacific right
whales in the GOA Study Area is expected to be rare due to the species'
extremely low population, these mitigation requirements would help
further avoid or further reduce the potential for impacts to occur
within North Pacific right whale feeding habitat, thus likely reducing
the number of takes of North Pacific right whales, as well as the
severity of any disturbances by reducing the likelihood that feeding is
interrupted, delayed, or precluded for some limited amount of time.
Additionally, the North Pacific Right Whale Mitigation Area
overlaps with a small portion of the humpback whale critical habitat
Unit 5, in the southwest corner of the TMAA. While the overlap of the
two areas is limited, mitigation in the North Pacific Right Whale
Mitigation Area may reduce the number and/or severity of takes of
humpback whales in this important area.
The mitigation in this area would also help avoid or reduce
potential impacts on fish and invertebrates that inhabit the mitigation
area and which marine mammals prey upon. As described in Section
5.4.1.5 (Fisheries Habitats) of the 2020 GOA DSEIS/OEIS, the productive
waters off Kodiak Island support a strong trophic system from plankton,
invertebrates, small fish, and higher-level predators, including large
fish and marine mammals.
Continental Shelf and Slope Mitigation Area
The Continental Shelf and Slope Mitigation Area encompasses the
portion of the continental shelf and slope that overlaps the TMAA (the
entire continental shelf and slope out to the 4,000 m depth contour;
Figure 2). The Navy would not detonate explosives below 10,000 ft.
altitude (including at the water surface) in the Continental Shelf and
Slope Mitigation Area during training. (As stated previously, the Navy
does not plan to use in-water explosives anywhere in the GOA Study
Area.) Mitigation in the Continental Shelf and Slope Mitigation Area
was initially designed to avoid or reduce potential impacts on fishery
resources for Alaska Natives. However, the area includes highly
productive waters where marine mammals, including humpback whales
(Lagerquist et al. 2008) and North Pacific right whales, feed, and
overlaps with a small portion of the North Pacific right whale feeding
BIA off of Kodiak Island. Additionally, the Continental Shelf and Slope
Mitigation Area overlaps with a very small portion of the humpback
whale critical habitat Unit 5, on the western side of the TMAA, and a
small portion of humpback whale critical habitat Unit 8 on the north
side of the TMAA. The Continental Shelf and Slope mitigation area also
overlaps with a very small portion of the gray whale migration BIA. The
remainder of the designated critical habitat and BIAs are located
beyond the boundaries of the GOA Study Area. While the overlap of the
mitigation area with critical habitat and feeding and migratory BIAs is
limited, mitigation in the Continental Shelf and Slope Mitigation Area
may reduce the probability, number, and/or severity of takes of
humpback whales, North Pacific right whales, and gray whales in this
important area (noting that no takes are predicted for gray whales).
Additionally, mitigation in this area will likely reduce the number and
severity of potential impacts to marine mammals in general, by reducing
the likelihood that feeding is interrupted, delayed, or precluded for
some limited amount of time.
Pre-Event Awareness Notifications in the Temporary Maritime Activities
Area
The Navy will issue awareness messages prior to the start of TMAA
training activities to alert vessels and aircraft operating within the
TMAA to the possible presence of concentrations of large whales,
including but not limited to, fin whale, blue whale, humpback whale,
gray whales, North Pacific right whale, sei whale, minke whale, and
sperm whale, especially when traversing on the continental shelf and
slope where densities of these species may be higher. To maintain
safety of navigation and to avoid interactions with marine mammals, the
Navy will instruct vessels to remain vigilant to the presence of large
whales that may be vulnerable to vessel strikes or potential impacts
from training activities. Navy personnel will use the information from
the awareness notification messages to assist their visual observation
of applicable mitigation zones during training activities and to aid in
the implementation of procedural mitigation.
This mitigation would help avoid or further reduce any potential
impacts from vessel strikes and training activities on large whales
within the TMAA.
Availability for Subsistence Uses
The nature of subsistence activities by Alaska Natives in the GOA
Study Area are discussed below, in the Subsistence Harvest of Marine
Mammals section of this proposed rule.
Mitigation Conclusions
NMFS has carefully evaluated the Navy's proposed mitigation
measures--many of which were developed with NMFS' input during the
previous phases of Navy training authorizations but several of which
are new since implementation of the 2017 to 2022 regulations--and
considered a broad range of other measures (i.e., the measures
considered but eliminated in the 2020 GOA DSEIS/OEIS, which reflect
many of the comments that have arisen from public input or through
discussion with NMFS in past years) in the context of ensuring that
NMFS prescribes the means of effecting the least practicable adverse
impact on the affected marine mammal species and their habitat. Our
evaluation of potential measures included consideration of the
following factors in relation to one another: the manner in which, and
the degree to which, the successful implementation of the mitigation
measures is expected to reduce the likelihood and/or magnitude of
adverse impacts to marine mammal species and their habitat; the proven
or likely efficacy of the measures; and the practicability of the
measures for applicant implementation, including consideration of
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
Based on our evaluation of the Navy's proposed measures, as well as
other measures considered by the Navy and NMFS, NMFS has preliminarily
determined that these proposed mitigation measures are appropriate
means of effecting the least practicable adverse impact on marine
mammal species and their habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and
considering specifically personnel safety, practicality of
implementation, and impact on the effectiveness of the military
readiness activity. Additionally, an adaptive management component
helps further ensure that mitigation is regularly assessed and provides
a mechanism to improve the mitigation, based on the factors above,
through modification as appropriate.
The proposed rule comment period provides the public an opportunity
to submit recommendations, views, and/or concerns regarding the Navy's
activities and the proposed mitigation measures. While NMFS has
preliminarily determined that the Navy's proposed mitigation measures
would effect the least practicable adverse impact on the affected
species and their habitat, NMFS
[[Page 49732]]
will consider all public comments to help inform our final
determination. Consequently, the proposed mitigation measures may be
refined, modified, removed, or added to prior to the issuance of the
final rule based on public comments received and, as appropriate,
analysis of additional potential mitigation measures.
Proposed Monitoring
Section 101(a)(5)(A) of the MMPA states that in order to authorize
incidental take for an activity, NMFS must set forth requirements
pertaining to the monitoring and reporting of such taking. The MMPA
implementing regulations at 50 CFR 216.104(a)(13) indicate that
requests for incidental take authorizations must include the suggested
means of accomplishing the necessary monitoring and reporting that will
result in increased knowledge of the species and of the level of taking
or impacts on populations of marine mammals that are expected to be
present.
Although the Navy has been conducting research and monitoring for
over 20 years in areas where it has been training, it developed a
formal marine species monitoring program in support of the GOA Study
Area MMPA and ESA processes in 2009. Across all Navy training and
testing study areas, the robust marine species monitoring program has
resulted in hundreds of technical reports and publications on marine
mammals that have informed Navy and NMFS analyses in environmental
planning documents, rules, and Biological Opinions. The reports are
made available to the public on the Navy's marine species monitoring
website (www.navymarinespeciesmonitoring.us) and the data on the Ocean
Biogeographic Information System Spatial Ecological Analysis of
Megavertebrate Populations (OBIS-SEAMAP) (https://seamap.env.duke.edu/
).
The Navy would continue collecting monitoring data to inform our
understanding of the occurrence of marine mammals in the GOA Study
Area; the likely exposure of marine mammals to stressors of concern in
the GOA Study Area; the response of marine mammals to exposures to
stressors; the consequences of a particular marine mammal response to
their individual fitness and, ultimately, populations; and the
effectiveness of implemented mitigation measures. Taken together,
mitigation and monitoring comprise the Navy's integrated approach for
reducing environmental impacts from the specified activities. The
Navy's overall monitoring approach seeks to leverage and build on
existing research efforts whenever possible.
As agreed upon between the Navy and NMFS, the monitoring measures
presented here, as well as the mitigation measures described above,
focus on the protection and management of potentially affected marine
mammals. A well-designed monitoring program can provide important
feedback for validating assumptions made in analyses and allow for
adaptive management of marine resources. Monitoring is required under
the MMPA, and details of the monitoring program for the specified
activities have been developed through coordination between NMFS and
the Navy through the regulatory process for previous Navy at-sea
training and testing activities.
Integrated Comprehensive Monitoring Program
The Navy's Integrated Comprehensive Monitoring Program (ICMP) is
intended to coordinate marine species monitoring efforts across all
regions and to allocate the most appropriate level and type of effort
for each range complex based on a set of standardized objectives, and
in acknowledgement of regional expertise and resource availability. The
ICMP is designed to be flexible, scalable, and adaptable through the
adaptive management and strategic planning processes to periodically
assess progress and reevaluate objectives. This process includes
conducting an annual adaptive management review meeting, at which the
Navy and NMFS jointly consider the prior-year goals, monitoring
results, and related scientific advances to determine if monitoring
plan modifications are warranted to more effectively address program
goals. Although the ICMP does not specify actual monitoring field work
or individual projects, it does establish a matrix of goals and
objectives that have been developed in coordination with NMFS. As the
ICMP is implemented through the Strategic Planning Process, detailed
and specific studies will be developed which support the Navy's and
NMFS top-level monitoring goals. In essence, the ICMP directs that
monitoring activities relating to the effects of Navy training and
testing activities on marine species should be designed to contribute
towards or accomplish one or more of the following top-level goals:
An increase in the understanding of the likely occurrence
of marine mammals and ESA-listed marine species in the vicinity of the
action (i.e., presence, abundance, distribution, and density of
species);
An increase in the understanding of the nature, scope, or
context of the likely exposure of marine mammals and ESA-listed species
to any of the potential stressors associated with the action (e.g.,
sound, explosive detonation, or expended materials), through better
understanding of one or more of the following: (1) the nature of the
action and its surrounding environment (e.g., sound-source
characterization, propagation, and ambient noise levels), (2) the
affected species (e.g., life history or dive patterns), (3) the likely
co-occurrence of marine mammals and ESA-listed marine species with the
action (in whole or part), and (4) the likely biological or behavioral
context of exposure to the stressor for the marine mammal and ESA-
listed marine species (e.g., age class of exposed animals or known
pupping, calving, or feeding areas);
An increase in the understanding of how individual marine
mammals or ESA-listed marine species respond (behaviorally or
physiologically) to the specific stressors associated with the action
(in specific contexts, where possible, e.g., at what distance or
received level);
An increase in the understanding of how anticipated
individual responses, to individual stressors or anticipated
combinations of stressors, may impact either (1) the long-term fitness
and survival of an individual; or (2) the population, species, or stock
(e.g., through impacts on annual rates of recruitment or survival);
An increase in the understanding of the effectiveness of
mitigation and monitoring measures;
A better understanding and record of the manner in which
the Navy complies with the incidental take regulations and LOAs and the
ESA Incidental Take Statement;
An increase in the probability of detecting marine mammals
(through improved technology or methods), both specifically within the
mitigation zone (thus allowing for more effective implementation of the
mitigation) and in general, to better achieve the above goals; and
Ensuring that adverse impacts of activities remain at the
least practicable level.
Strategic Planning Process for Marine Species Monitoring
The Navy also developed the Strategic Planning Process for Marine
Species Monitoring, which serves to guide the investment of resources
to most efficiently address ICMP objectives and intermediate scientific
objectives developed through this process. The
[[Page 49733]]
Strategic Planning Process establishes the guidelines and processes
necessary to develop, evaluate, and fund individual projects based on
objective scientific study questions. The process uses an underlying
framework designed around intermediate scientific objectives and a
conceptual framework incorporating a progression of knowledge spanning
occurrence, exposure, response, and consequence. The Strategic Planning
Process for Marine Species Monitoring is used to set overarching
intermediate scientific objectives; develop individual monitoring
project concepts; evaluate, prioritize, and select specific monitoring
projects to fund or continue supporting for a given fiscal year;
execute and manage selected monitoring projects; and report and
evaluate progress and results. This process addresses relative
investments to different range complexes based on goals across all
range complexes, and monitoring would leverage multiple techniques for
data acquisition and analysis whenever possible. More information on
the Strategic Planning Process for Marine Species Monitoring including
results, reports, and publications, is also available online (https://www.navymarinespeciesmonitoring.us/).
Past and Current Monitoring in the GOA Study Area
The monitoring program has undergone significant changes since the
first rule was issued for the TMAA in 2011, which highlights the
monitoring program's evolution through the process of adaptive
management. The monitoring program developed for the first cycle of
environmental compliance documents (e.g., U.S. Department of the Navy,
2008a, 2008b) utilized effort-based compliance metrics that were
somewhat limiting. Through adaptive management discussions, the Navy
designed and conducted monitoring studies according to scientific
objectives and eliminated specific effort requirements.
Progress has also been made on the conceptual framework categories
from the Scientific Advisory Group for Navy Marine Species Monitoring
(U.S. Department of the Navy, 2011), ranging from occurrence of
animals, to their exposure, response, and population consequences. The
Navy continues to manage the Atlantic and Pacific program as a whole,
including what is now the GOA Study Area, with monitoring in each range
complex taking a slightly different but complementary approach. The
Navy has continued to use the approach of layering multiple
simultaneous components in many of the range complexes to leverage an
increase in return of the progress toward answering scientific
monitoring questions. This includes in the TMAA, for example (a)
Passive Acoustic Monitoring for Marine Mammals in the Gulf of Alaska
Temporary Maritime Activities Area May to September 2015 and April to
September 2017 (Rice et al., 2018b); (b) analysis of existing passive
acoustic monitoring datasets; and (c) Passive Acoustic Monitoring of
Marine Mammals Using Gliders (Klinck et al., 2016).
Numerous publications, dissertations, and conference presentations
have resulted from research conducted under the marine species
monitoring program, including research conducted in what is now the GOA
Study Area (https://www.navymarinespeciesmonitoring.us/reading-room/publications/), leading to a significant contribution to the body of
marine mammal science. Publications on occurrence, distribution, and
density have fed the modeling input, and publications on exposure and
response have informed Navy and NMFS analysis of behavioral response
and consideration of mitigation measures.
Furthermore, collaboration between the monitoring program and the
Navy's research and development (e.g., the Office of Naval Research)
and demonstration-validation (e.g., Living Marine Resources) programs
has been strengthened, leading to research tools and products that have
already transitioned to the monitoring program. These include Marine
Mammal Monitoring on Ranges, controlled exposure experiment behavioral
response studies, acoustic sea glider surveys, and global positioning
system-enabled satellite tags. Recent progress has been made with
better integration with monitoring across all Navy at-sea study areas,
including the AFTT Study Area in the Atlantic Ocean, and various other
ranges. Publications from the Living Marine Resources and Office of
Naval Research programs have also resulted in significant contributions
to hearing, acoustic criteria used in effects modeling, exposure, and
response, as well as in developing tools to assess biological
significance (e.g., consequences).
NMFS and the Navy also consider data collected during procedural
mitigations as monitoring. Data are collected by shipboard personnel on
hours spent training, hours of observation, hours of sonar, and marine
mammals observed within the mitigation zones when mitigations are
implemented. These data are provided to NMFS in both classified and
unclassified annual training reports, which would continue under this
proposed rule.
NMFS has received multiple years' worth of annual training and
monitoring reports addressing active sonar use and explosive
detonations within the TMAA and other Navy range complexes. The data
and information contained in these reports have been considered in
developing mitigation and monitoring measures for the proposed training
activities within the GOA Study Area. The Navy's annual training and
monitoring reports may be viewed at: https://www.navymarinespeciesmonitoring.us/reporting/.
The Navy's marine species monitoring program supports monitoring
projects in the GOA Study Area. Additional details on the scientific
objectives for each project can be found at https://www.navymarinespeciesmonitoring.us/regions/pacific/current-projects/.
Projects can be either major multi-year efforts, or one to 2-year
special studies. The emphasis on monitoring in the GOA Study Area is
directed towards collecting and analyzing passive acoustic monitoring
and telemetry data for marine mammals and salmonids.
Specific monitoring under the previous regulations (which covered
only the TMAA) included:
The continuation of the Navy's collaboration with NOAA on
the Pacific Marine Assessment Program for Protected Species (PacMAPPS)
survey. A systematic line transect survey in the Gulf of Alaska was
completed in 2021. A second PacMAPPS survey is planned for the Gulf of
Alaska in 2023. These surveys will increase knowledge of marine mammal
occurrence, density, and population identity in the TMAA.
A Characterizing the Distribution of ESA-Listed Salmonids
in Washington and Alaska study. The goal of this study is to use a
combination of acoustic and pop-up satellite tagging technology to
provide critical information on spatial and temporal distribution of
salmonids to inform salmon management, U.S. Navy training activities,
and Southern Resident killer whale conservation. The study seeks to (1)
determine the occurrence and timing of salmonids within the Navy
training ranges; (2) describe the influence of environmental covariates
on salmonid occurrence; and (3) describe the occurrence of salmonids in
relation to Southern Resident killer whale distribution. Methods
include acoustic telemetry (pinger tags) and pop-up satellite tagging.
A Telemetry and Genetic Identity of Chinook Salmon in
Alaska study. The goal of this study is to provide critical
[[Page 49734]]
information on the spatial and temporal distribution of Chinook salmon
and to utilize genetic analysis techniques to inform salmon management.
Tagging is occurring at several sites within the Gulf of Alaska.
A North Pacific Humpback Whale Tagging study. This project
combines tagging, biopsy sampling, and photo-identification efforts
along the United States west coast and Hawaii to examine movement
patterns and whale use of Navy training and testing areas and NMFS-
identified BIAs, examine migration routes, and analyze dive behavior
and ecological relationships between whale locations and oceanographic
conditions (Mate et al., 2017; Irvine et al., 2020).
Future monitoring efforts in the GOA Study Area are anticipated to
continue along the same objectives: determining the species and
populations of marine mammals present and potentially exposed to Navy
training activities in the GOA Study Area, through tagging, passive
acoustic monitoring, refined modeling, photo identification, biopsies,
and visual monitoring, as well as characterizing spatial and temporal
distribution of salmonids, including Chinook salmon.
Adaptive Management
The proposed regulations governing the take of marine mammals
incidental to Navy training activities in the GOA Study Area contain an
adaptive management component. Our understanding of the effects of Navy
training activities (e.g., acoustic and explosive stressors) on marine
mammals continues to evolve, which makes the inclusion of an adaptive
management component both valuable and necessary within the context of
7-year regulations.
The reporting requirements associated with this rule are designed
to provide NMFS with monitoring data from the previous year to allow
NMFS to consider whether any changes to existing mitigation and
monitoring requirements are appropriate. The use of adaptive management
allows NMFS to consider new information from different sources to
determine (with input from the Navy regarding practicability) on an
annual or biennial basis if mitigation or monitoring measures should be
modified (including additions or deletions). Mitigation measures could
be modified if new data suggests that such modifications would have a
reasonable likelihood of more effectively accomplishing the goals of
the mitigation and monitoring and if the measures are practicable. If
the modifications to the mitigation, monitoring, or reporting measures
are substantial, NMFS would publish a notice of the planned LOA in the
Federal Register and solicit public comment.
The following are some of the possible sources of applicable data
to be considered through the adaptive management process: (1) results
from monitoring and exercise reports, as required by MMPA
authorizations; (2) compiled results of Navy funded research and
development studies; (3) results from specific stranding
investigations; (4) results from general marine mammal and sound
research; and (5) any information which reveals that marine mammals may
have been taken in a manner, extent, or number not authorized by these
regulations or subsequent LOA. The results from monitoring reports and
other studies may be viewed at https://www.navymarinespeciesmonitoring.us.
Proposed Reporting
In order to issue incidental take authorization for an activity,
section 101(a)(5)(A) of the MMPA states that NMFS must set forth
requirements pertaining to the monitoring and reporting of such taking.
Effective reporting is critical both to compliance as well as ensuring
that the most value is obtained from the required monitoring. Reports
from individual monitoring events, results of analyses, publications,
and periodic progress reports for specific monitoring projects would be
posted to the Navy's Marine Species Monitoring web portal: https://www.navymarinespeciesmonitoring.us.
There are several different reporting requirements pursuant to the
2017-2022 regulations. All of these reporting requirements would be
continued under this proposed rule for the 7-year period; however, the
reporting schedule for the GOA Annual Training Report would be slightly
changed to align the reporting schedule with the activity period (see
the GOA Annual Training Report section, below).
Notification of Injured, Live Stranded, or Dead Marine Mammals
The Navy would consult the Notification and Reporting Plan, which
sets out notification, reporting, and other requirements when injured,
live stranded, or dead marine mammals are detected. The Notification
and Reporting Plan is available for review at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.
Annual GOA Marine Species Monitoring Report
The Navy would submit an annual report to NMFS of the GOA Study
Area monitoring, which would be included in a Pacific-wide monitoring
report and include results specific to the GOA Study Area, describing
the implementation and results of monitoring from the previous calendar
year. Data collection methods would be standardized across Pacific
Range Complexes including the MITT, HSTT, NWTT, and GOA Study Areas to
the best extent practicable, to allow for comparison among different
geographic locations. The report would be submitted to the Director,
Office of Protected Resources, NMFS, either within 3 months after the
end of the calendar year, or within 3 months after the conclusion of
the monitoring year, to be determined by the Adaptive Management
process. NMFS would submit comments or questions on the draft
monitoring report, if any, within 3 months of receipt. The report would
be considered final after the Navy has addressed NMFS' comments, or 3
months after submittal if NMFS does not provide comments on the report.
The report would describe progress of knowledge made with respect to
monitoring study questions across multiple Navy ranges associated with
the ICMP. Similar study questions would be treated together so that
progress on each topic is summarized across all Navy ranges. The report
need not include analyses and content that does not provide direct
assessment of cumulative progress on the monitoring plan study
questions. This would allow the Navy to provide a cohesive monitoring
report covering multiple ranges (as per ICMP goals), rather than
entirely separate reports for the MITT, HSTT, NWTT, and GOA Study
Areas.
GOA Annual Training Report
Each year in which training activities are conducted in the GOA
Study Area, the Navy would submit one preliminary report (Quick Look
Report) to NMFS detailing the status of applicable sound sources within
21 days after the completion of the training activities in the GOA
Study Area. Each year in which activities are conducted, the Navy would
also submit a detailed report (GOA Annual Training Report) to NMFS
within 3 months after completion of the training activities. The Phase
II rule required the Navy to submit the GOA Annual Training Report
within 3 months after the anniversary of the date of issuance of the
LOA. NMFS would submit comments or questions on the
[[Page 49735]]
report, if any, within one month of receipt. The report would be
considered final after the Navy has addressed NMFS' comments, or one
month after submittal if NMFS does not provide comments on the report.
The annual reports would contain information about the MTE, (exercise
designator, date that the exercise began and ended, location, number
and types of active and passive sonar sources used in the exercise,
number and types of vessels and aircraft that participated in the
exercise, etc.), individual marine mammal sighting information for each
sighting in each exercise where mitigation was implemented, a
mitigation effectiveness evaluation, and a summary of all sound sources
used (total hours or quantity of each bin of sonar or other non-
impulsive source; total annual number of each type of explosive(s); and
total annual expended/detonated rounds (bombs and large-caliber
projectiles) for each explosive bin).
The annual report (which, as stated above, would only be required
during years in which activities are conducted) would also contain
cumulative sonar and explosive use quantity from previous years'
reports through the current year. Additionally, if there were any
changes to the sound source allowance in the reporting year, or
cumulatively, the report would include a discussion of why the change
was made and include analysis to support how the change did or did not
affect the analysis in the GOA SEIS/OEIS and MMPA final rule. The
analysis in the detailed report would be based on the accumulation of
data from the current year's report and data collected from previous
annual reports. The final annual/close-out report at the conclusion of
the authorization period (year seven) would also serve as the
comprehensive close-out report and include both the final year annual
use compared to annual authorization as well as a cumulative 7-year
annual use compared to 7-year authorization. This report would also
note any years in which training did not occur. NMFS must submit
comments on the draft close-out report, if any, within 3 months of
receipt. The report would be considered final after the Navy has
addressed NMFS' comments, or 3 months after the submittal of the draft
if NMFS does not provide comments. Information included in the annual
reports may be used to inform future adaptive management of activities
within the GOA Study Area. See the regulations below for more detail on
the content of the annual report.
Other Reporting and Coordination
The Navy would continue to report and coordinate with NMFS for the
following:
Annual marine species monitoring technical review meetings
that also include researchers and the Marine Mammal Commission; and
Annual Adaptive Management meetings that also include the
Marine Mammal Commission (and occur in conjunction with the annual
marine species monitoring technical review meetings).
Preliminary Analysis and Negligible Impact Determination
General Negligible Impact Analysis
Introduction
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. For Level A
harassment or Level B harassment (as presented in Table 30), in
addition to considering estimates of the number of marine mammals that
might be taken NMFS considers other factors, such as the likely nature
of any responses (e.g., intensity, duration) and the context of any
responses (e.g., critical reproductive time or location, migration), as
well as effects on habitat and the likely effectiveness of the
mitigation. We also assess the number, intensity, and context of
estimated takes by evaluating this information relative to population
status. Consistent with the 1989 preamble for NMFS' implementing
regulations (54 FR 40338; September 29, 1989), the impacts from other
past and ongoing anthropogenic activities are incorporated into this
analysis via their impacts on the environmental baseline (e.g., as
reflected in the regulatory status of the species, population size and
growth rate where known, other ongoing sources of human-caused
mortality, and ambient noise levels).
In the Estimated Take of Marine Mammals section, we identified the
subset of potential effects that would be expected to rise to the level
of takes both annually and over the 7-year period covered by this
proposed rule, and then identified the maximum number of harassment
takes that are reasonably expected to occur based on the methods
described. The impact that any given take would have is dependent on
many case-specific factors that need to be considered in the negligible
impact analysis (e.g., the context of behavioral exposures such as
duration or intensity of a disturbance, the health of impacted animals,
the status of a species that incurs fitness-level impacts to
individuals, etc.). For this proposed rule we evaluated the likely
impacts of the enumerated maximum number of harassment takes that are
proposed for authorization and reasonably expected to occur, in the
context of the specific circumstances surrounding these predicted
takes. Last, we collectively evaluated this information, as well as
other more taxa-specific information and mitigation measure
effectiveness, in group-specific assessments that support our
negligible impact conclusions for each stock or species. Because all of
the Navy's specified activities would occur within the ranges of the
marine mammal stocks identified in the rule, all negligible impact
analyses and determinations are at the stock level (i.e., additional
species-level determinations are not needed).
As explained in the Estimated Take of Marine Mammals section, no
take by serious injury or mortality is authorized or anticipated to
occur. There have been no recorded Navy vessel strikes of any marine
mammals during training in the GOA Study Area to date, nor were
incidental takes by injury or mortality resulting from vessel strike
predicted in the Navy's analysis. For these and the other reasons
described in the Potential Effects of Vessel Strike section, NMFS
concurs that vessel strike is not likely to occur during the 21-day GOA
Study Area training activities, and therefore is not proposing
authorization in this rule.
The specified activities reflect representative levels of training
activities. The Description of the Specified Activity section describes
annual activities. There may be some flexibility in the exact number of
hours, items, or detonations that may vary from year to year, but take
totals would not exceed the maximum annual totals and 7-year totals
indicated in Table 30. (Further, as noted previously, the GOA Study
Area training activities would not occur continuously throughout the
year, but rather, for a maximum of 21 days once annually between April
and October.) We base our analysis and negligible impact determination
on the maximum number of takes that would be reasonably expected to
occur annually and are proposed to be authorized, although, as stated
before,
[[Page 49736]]
the number of takes is only a part of the analysis, which includes
extensive qualitative consideration of other contextual factors that
influence the degree of impact of the takes on the affected
individuals. To avoid repetition, we provide some general analysis
immediately below that applies to all the species listed in Table 30,
given that some of the anticipated effects of the Navy's training
activities on marine mammals are expected to be relatively similar in
nature. However, below that, we break our analysis into species (and/or
stocks), or groups of species (and the associated stocks) where
relevant similarities exist, to provide more specific information
related to the anticipated effects on individuals of a specific stock
or where there is information about the status or structure of any
species or stock that would lead to a differing assessment of the
effects on the species or stock. Organizing our analysis by grouping
species or stocks that share common traits or that would respond
similarly to effects of the Navy's activities and then providing
species- or stock-specific information allows us to avoid duplication
while assuring that we have analyzed the effects of the specified
activities on each affected species or stock.
Harassment
The Navy's harassment take request is based on a model and
quantitative assessment of mitigation, which NMFS reviewed and concurs
appropriately predicts the maximum amount of harassment that is
reasonably likely to occur, with the exception of the Eastern North
Pacific stock of gray whale, and the Western North Pacific stock of
humpback whale, for which NMFS has proposed authorizing 4 and 3 Level B
harassment takes annually, respectively, as described in the Estimated
Take of Marine Mammals section. The model calculates sound energy
propagation from sonar, other active acoustic sources, and explosives
during naval activities; the sound or impulse received by animat
dosimeters representing marine mammals distributed in the area around
the modeled activity; and whether the sound or impulse energy received
by a marine mammal exceeds the thresholds for effects. Assumptions in
the Navy model intentionally err on the side of overestimation when
there are unknowns. Naval activities are modeled as though they would
occur regardless of proximity to marine mammals, meaning that no
mitigation is considered (e.g., no power down or shut down) and without
any avoidance of the activity by the animal. As described above in the
Estimated Take of Marine Mammals section, no mortality was modeled for
any species for the TMAA activities, and therefore the quantitative
post-modeling analysis that allows for the consideration of mitigation
to prevent mortality, which has been applied in other Navy rules, was
appropriately not applied here. (Though, as noted in the Estimated Take
of Marine Mammals section, where the analysis indicates mitigation
would effectively reduce risk, the model-estimated PTS are considered
reduced to TTS.) NMFS provided input to, independently reviewed, and
concurs with the Navy on this process and the Navy's analysis, which is
described in detail in Section 6 of the Navy's rulemaking/LOA
application, that was used to quantify harassment takes for this rule.
Generally speaking, the Navy and NMFS anticipate more severe
effects from takes resulting from exposure to higher received levels
(though this is in no way a strictly linear relationship for behavioral
effects throughout species, individuals, or circumstances) and less
severe effects from takes resulting from exposure to lower received
levels. However, there is also growing evidence of the importance of
distance in predicting marine mammal behavioral response to sound--
i.e., sounds of a similar level emanating from a more distant source
have been shown to be less likely to evoke a response of equal
magnitude (DeRuiter 2012, Falcone et al. 2017). The estimated number of
takes by Level A harassment and Level B harassment does not equate to
the number of individual animals the Navy expects to harass (which is
lower), but rather to the instances of take (i.e., exposures above the
Level A harassment and Level B harassment threshold) that are
anticipated to occur annually and over the 7-year period. These
instances may represent either brief exposures (seconds or minutes) or,
in some cases, longer durations of exposure within a day. Some
individuals may experience multiple instances of take (meaning over
multiple days) over the course of the 21 day exercise, which means that
the number of individuals taken is smaller than the total estimated
takes. Generally speaking, the higher the number of takes as compared
to the population abundance, the more repeated takes of individuals are
likely, and the higher the actual percentage of individuals in the
population that are likely taken at least once in a year. We look at
this comparative metric to give us a relative sense of where a larger
portion of a species is being taken by Navy activities, where there is
a higher likelihood that the same individuals are being taken across
multiple days, and where that number of days might be higher or more
likely sequential. Where the number of instances of take is less than
100 percent of the abundance and there is no information to
specifically suggest that a small subset of animals is being repeatedly
taken over a high number of sequential days, the overall magnitude is
generally considered low, as it could on one extreme mean that every
take represents a separate individual in the population being taken on
one day (a very minimal impact) or, more likely, that some smaller
number of individuals are taken on one day annually and some are taken
on a few not likely sequential days annually, while some are not taken
at all.
In the ocean, the use of sonar and other active acoustic sources is
often transient and is unlikely to repeatedly expose the same
individual animals within a short period, for example within one
specific exercise. However, for some individuals of some species
repeated exposures across different activities could occur across the
21-day period. In short, for some species we expect that the total
anticipated takes represent exposures of a smaller number of
individuals of which some would be exposed multiple times, but based on
the nature of the Navy activities and the movement patterns of marine
mammals, it is unlikely that individuals from most stocks would be
taken over more than a few non-sequential days. This means that even
where repeated takes of individuals may occur, they are more likely to
result from non-sequential exposures from different activities, and,
even if a few individuals were taken on sequential days, they are not
predicted to be taken for more than a few days in a row, at most. As
described elsewhere, the nature of the majority of the exposures would
be expected to be of a less severe nature and based on the numbers and
duration of the activity (no more than 21 days) any individual exposed
multiple times is still only taken on a small percentage of the days of
the year.
Physiological Stress Response
Some of the lower level physiological stress responses (e.g.,
orientation or startle response, change in respiration, change in heart
rate) discussed earlier would likely co-occur with the predicted
harassments, although these responses are more difficult to detect and
fewer data exist relating these responses to specific received levels
of sound. Takes by Level A harassment or Level B harassment, then, may
have a
[[Page 49737]]
stress-related physiological component as well; however, we would not
expect the Navy's generally short-term, intermittent, and (typically in
the case of sonar) transitory activities to create conditions of long-
term continuous noise leading to long-term physiological stress
responses in marine mammals that could affect reproduction or survival.
Behavioral Response
The estimates calculated using the BRF do not differentiate between
the different types of behavioral responses that rise to the level of
take by Level B harassment. As described in the Navy's application, the
Navy identified (with NMFS' input) the types of behaviors that would be
considered a take: Moderate behavioral responses as characterized in
Southall et al. (2007) (e.g., altered migration paths or dive profiles,
interrupted nursing, breeding or feeding, or avoidance) that also would
be expected to continue for the duration of an exposure. The Navy then
compiled the available data indicating at what received levels and
distances those responses have occurred, and used the indicated
literature to build biphasic behavioral response curves that are used
to predict how many instances of Level B harassment by behavioral
disturbance occur in a day. Take estimates alone do not provide
information regarding the potential fitness or other biological
consequences of the reactions on the affected individuals. We therefore
consider the available activity-specific, environmental, and species-
specific information to determine the likely nature of the modeled
behavioral responses and the potential fitness consequences for
affected individuals.
Use of sonar and other transducers would typically be transient and
temporary. The majority of acoustic effects to individual animals from
sonar and other active sound sources during training activities would
be primarily from ASW events. It is important to note that although ASW
is one of the warfare areas of focus during Navy training, there are
significant periods when active ASW sonars are not in use. Behavioral
reactions are assumed more likely to be significant during MTEs than
during other ASW activities due to the use of high-powered ASW sources
as well as the duration (i.e., multiple days) and scale (i.e., multiple
sonar platforms) of the MTEs.
On the less severe end, exposure to comparatively lower levels of
sound at a detectably greater distance from the animal, for a few or
several minutes, could result in a behavioral response such as avoiding
an area that an animal would otherwise have moved through or fed in, or
breaking off one or a few feeding bouts. More severe effects could
occur when the animal gets close enough to the source to receive a
comparatively higher level of sound, is exposed continuously to one
source for a longer time, or is exposed intermittently to different
sources throughout a day. Such effects might result in an animal having
a more severe flight response and leaving a larger area for a day or
more or potentially losing feeding opportunities for a day. However,
such severe behavioral effects are expected to occur infrequently.
To help assess this, for sonar (MFAS/HFAS) used in the TMAA, the
Navy provided information estimating the percentage of animals that may
be taken by Level B harassment under each BRF that would occur within
6-dB increments (percentages discussed below in the Group and Species-
Specific Analyses section). As mentioned above, all else being equal,
an animal's exposure to a higher received level is more likely to
result in a behavioral response that is more likely to lead to adverse
effects, which could more likely accumulate to impacts on reproductive
success or survivorship of the animal, but other contextual factors
(such as distance) are also important. The majority of takes by Level B
harassment are expected to be in the form of milder responses (i.e.,
lower-level exposures that still rise to the level of take, but would
likely be less severe in the range of responses that qualify as take)
of a generally shorter duration. We anticipate more severe effects from
takes when animals are exposed to higher received levels of sound or at
closer proximity to the source. Because species belonging to taxa that
share common characteristics are likely to respond and be affected in
similar ways, these discussions are presented within each species group
below in the Group and Species-Specific Analyses section. As noted
previously in this proposed rule, behavioral responses vary
considerably between species, between individuals within a species, and
across contexts of different exposures. Specifically, given a range of
behavioral responses that may be classified as Level B harassment, to
the degree that higher received levels of sound are expected to result
in more severe behavioral responses, only a smaller percentage of the
anticipated Level B harassment from Navy activities might necessarily
be expected to potentially result in more severe responses (see the
Group and Species-Specific Analyses section below for more detailed
information). To fully understand the likely impacts of the predicted/
proposed authorized take on an individual (i.e., what is the likelihood
or degree of fitness impacts), one must look closely at the available
contextual information, such as the duration of likely exposures and
the likely severity of the exposures (e.g., whether they would occur
for a longer duration over sequential days or the comparative sound
level that would be received). Ellison et al. (2012) and Moore and
Barlow (2013), among others, emphasize the importance of context (e.g.,
behavioral state of the animals, distance from the sound source, etc.)
in evaluating behavioral responses of marine mammals to acoustic
sources.
Diel Cycle
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing on a diel cycle (24-hour cycle). Behavioral
reactions to noise exposure, when taking place in a biologically
important context, such as disruption of critical life functions,
displacement, or avoidance of important habitat, are more likely to be
significant if they last more than one diel cycle or recur on
subsequent days (Southall et al., 2007). Henderson et al. (2016) found
that ongoing smaller scale events had little to no impact on foraging
dives for Blainville's beaked whale, while multi-day training events
may decrease foraging behavior for Blainville's beaked whale (Manzano-
Roth et al., 2016). Consequently, a behavioral response lasting less
than one day and not recurring on subsequent days is not considered
severe unless it could directly affect reproduction or survival
(Southall et al., 2007). Note that there is a difference between
multiple-day substantive behavioral reactions and multiple-day
anthropogenic activities. For example, just because an at-sea exercise
lasts for multiple days does not necessarily mean that individual
animals are either exposed to those exercises for multiple days or,
further, exposed in a manner resulting in a sustained multiple day
substantive behavioral response. Large multi-day Navy exercises such as
ASW activities, typically include vessels that are continuously moving
at speeds typically 10-15 kn (19-28 km/hr), or higher, and likely cover
large areas that are relatively far from shore (typically more than 3
nmi (6 km) from shore) and in waters greater than 600 ft (183 m) deep.
Additionally marine mammals are moving as well, which would make it
unlikely that the same animal could remain in the immediate vicinity of
the ship for the entire duration of the
[[Page 49738]]
exercise. Further, the Navy does not necessarily operate active sonar
the entire time during an exercise. While it is certainly possible that
these sorts of exercises could overlap with individual marine mammals
multiple days in a row at levels above those anticipated to result in a
take, because of the factors mentioned above, it is considered unlikely
for the majority of takes. However, it is also worth noting that the
Navy conducts many different types of noise-producing activities over
the course of the 21-day exercise, and it is likely that some marine
mammals will be exposed to more than one activity and taken on multiple
days, even if they are not sequential.
Durations of Navy activities utilizing tactical sonar sources and
explosives vary and are fully described in Appendix A (Navy Activity
Descriptions) of the 2020 GOA DSEIS/OEIS. Sonar used during ASW would
impart the greatest amount of acoustic energy of any category of sonar
and other transducers analyzed in the Navy's rulemaking/LOA application
and include hull-mounted, towed array, sonobuoy, and helicopter dipping
sonars. Most ASW sonars are MFAS (1-10 kHz); however, some sources may
use higher frequencies. ASW training activities using hull mounted
sonar proposed for the TMAA generally last for only a few hours (see
Appendix A (Navy Activity Descriptions) of the 2020 GOA DSEIS/OEIS).
Some ASW training activities typically last about 8 hours. Because of
the need to train in a large variety of situations, the Navy does not
typically conduct successive ASW exercises in the same locations. Given
the average length of ASW exercises (times of sonar use) and typical
vessel speed, combined with the fact that the majority of the cetaceans
would not likely remain in proximity to the sound source, it is
unlikely that an animal would be exposed to MFAS/HFAS at levels or
durations likely to result in a substantive response that would then be
carried on for more than 1 day or on successive days (and as noted
previously, no LFAS use is planned by the Navy).
Most planned explosive events are scheduled to occur over a short
duration (1-3 hours); however, the explosive component of these
activities only lasts for minutes. Although explosive exercises may
sometimes be conducted in the same general areas repeatedly, because of
their short duration and the fact that they are in the open ocean and
animals can easily move away, it is similarly unlikely that animals
would be exposed for long, continuous amounts of time, or demonstrate
sustained behavioral responses. All of these factors make it unlikely
that individuals would be exposed to the exercise for extended periods
or on consecutive days, though some individuals may be exposed on
multiple days.
Assessing the Number of Individuals Taken and the Likelihood of
Repeated Takes
As described previously, Navy modeling uses the best available
science to predict the instances of exposure above certain acoustic
thresholds, which are equated, as appropriate, to harassment takes (and
further corrected to account for mitigation and avoidance). As further
noted, for active acoustics it is more challenging to parse out the
number of individuals taken by Level B harassment and the number of
times those individuals are taken from this larger number of instances.
One method that NMFS uses to help better understand the overall scope
of the impacts is to compare these total instances of take against the
abundance of that species (or stock if applicable). For example, if
there are 100 harassment takes in a population of 100, one can assume
either that every individual was exposed above acoustic thresholds in
no more than one day, or that some smaller number were exposed in one
day but a few of those individuals were exposed multiple days within a
year and a few were not exposed at all. Where the instances of take
exceed 100 percent of the population, multiple takes of some
individuals are predicted and expected to occur within a year.
Generally speaking, the higher the number of takes as compared to the
population abundance, the more multiple takes of individuals are
likely, and the higher the actual percentage of individuals in the
population that are likely taken at least once in a year. We look at
this comparative metric to give us a relative sense of where larger
portions of the species or stock are being taken by Navy activities and
where there is a higher likelihood that the same individuals are being
taken across multiple days and where that number of days might be
higher. It also provides a relative picture of the scale of impacts to
each species or stock.
In the ocean, unlike a modeling simulation with static animals, the
use of sonar and other active acoustic sources is often transient, and
is unlikely to repeatedly expose the same individual animals within a
short period, for example within one specific exercise. However, some
repeated exposures across different activities could occur over the
year with more resident species. Nonetheless, the episodic nature of
activities in the TMAA (21 days per year) would mean less frequent
exposures as compared to some other ranges. In short, we expect that
for some stocks, the total anticipated takes represent exposures of a
smaller number of individuals of which some could be exposed multiple
times, but based on the nature of the Navy's activities and the
movement patterns of marine mammals, it is unlikely that individuals of
most species or stocks would be taken over more than a few non-
sequential days within a year.
When calculating the proportion of a population affected by takes
(e.g., the number of takes divided by population abundance), which can
also be helpful in estimating the number of days over which some
individuals may be taken, it is important to choose an appropriate
population estimate against which to make the comparison. The SARs,
where available, provide the official population estimate for a given
species or stock in U.S. waters in a given year (and are typically
based solely on the most recent survey data). When the stock is known
to range well outside of U.S. Exclusive Economic Zone (EEZ) boundaries,
population estimates based on surveys conducted only within the U.S.
EEZ are known to be underestimates. The information used to estimate
take includes the best available survey abundance data to model density
layers. Accordingly, in calculating the percentage of takes versus
abundance for each species or stock in order to assist in understanding
both the percentage of the species or stock affected, as well as how
many days across a year individuals could be taken, we use the data
most appropriate for the situation. For the GOA Study Area, for all
species and stocks except for beaked whales for which SAR data are
unavailable, the most recent NMFS SARs are used to calculate the
proportion of a population affected by takes.
The estimates found in NMFS' SARs remain the official estimates of
stock abundance where they are current. These estimates are typically
generated from the most recent shipboard and/or aerial surveys
conducted. In some cases, NMFS' abundance estimates show substantial
year-to-year variability. However, for highly migratory species (e.g.,
large whales) or those whose geographic distribution extends well
beyond the boundaries of the GOA Study Area (e.g., populations with
distribution along the entire eastern Pacific Ocean rather than just
the GOA Study Area), comparisons to the SAR
[[Page 49739]]
are appropriate. Many of the stocks present in the GOA Study Area have
ranges significantly larger than the GOA Study Area and that abundance
is captured by the SAR. A good descriptive example is migrating large
whales, which occur seasonally in the GOA. Therefore, at any one time
there may be a stable number of animals, but over the course of the
potential activity period (April to October), the entire population
could occur in the GOA Study Area. Therefore, comparing the estimated
takes to an abundance, in this case the SAR abundance, which represents
the total population, may be more appropriate than modeled abundances
for only the GOA Study Area.
Temporary Threshold Shift
NMFS and the Navy have estimated that most species or stocks of
marine mammals in the TMAA may sustain some level of TTS from active
sonar. As mentioned previously, in general, TTS can last from a few
minutes to days, be of varying degree, and occur across various
frequency bandwidths, all of which determine the severity of the
impacts on the affected individual, which can range from minor to more
severe. Table 41 to Table 46 indicate the number of takes by TTS that
may be incurred by different species and stocks from exposure to active
sonar and explosives. The TTS sustained by an animal is primarily
classified by three characteristics:
1. Frequency--Available data (of mid-frequency hearing specialists
exposed to mid- or high-frequency sounds; Southall et al., 2007)
suggest that most TTS occurs in the frequency range of the source up to
one octave higher than the source (with the maximum TTS at \1/2\ octave
above). The Navy's MF sources, which are the highest power and most
numerous sources and the ones that cause the most take, utilize the 1-
10 kHz frequency band, which suggests that if TTS were to be induced by
any of these MF sources it would be in a frequency band somewhere
between approximately 2 and 20 kHz, which is in the range of
communication calls for many odontocetes, but below the range of the
echolocation signals used for foraging. There are fewer hours of HF
source use and the sounds would attenuate more quickly, plus they have
lower source levels, but if an animal were to incur TTS from these
sources, it would cover a higher frequency range (sources are between
10 and 100 kHz, which means that TTS could range up to 200 kHz), which
could overlap with the range in which some odontocetes communicate or
echolocate. However, HF systems are typically used less frequently and
for shorter time periods than surface ship and aircraft MF systems, so
TTS from these sources is unlikely. As noted previously, the Navy
proposes no LFAS use for the activities in this rulemaking. The
frequency provides information about the cues to which a marine mammal
may be temporarily less sensitive, but not the degree or duration of
sensitivity loss. The majority of sonar sources from which TTS may be
incurred occupy a narrow frequency band, which means that the TTS
incurred would also be across a narrower band (i.e., not affecting the
majority of an animal's hearing range). TTS from explosives would be
broadband.
2. Degree of the shift (i.e., by how many dB the sensitivity of the
hearing is reduced)--Generally, both the degree of TTS and the duration
of TTS will be greater if the marine mammal is exposed to a higher
level of energy (which would occur when the peak dB level is higher or
the duration is longer). The threshold for the onset of TTS was
discussed previously in this rule. An animal would have to approach
closer to the source or remain in the vicinity of the sound source
appreciably longer to increase the received SEL, which would be
difficult considering the Lookouts and the nominal speed of an active
sonar vessel (10-15 kn; 19-28 km/hr) and the relative motion between
the sonar vessel and the animal. In the TTS studies discussed in the
Potential Effects of Specified Activities on Marine Mammals and their
Habitat section, some using exposures of almost an hour in duration or
up to 217 SEL, most of the TTS induced was 15 dB or less, though
Finneran et al. (2007) induced 43 dB of TTS with a 64-second exposure
to a 20 kHz source. However, since any hull-mounted sonar such as the
SQS-53 (MFAS), emits a ping typically every 50 seconds, incurring those
levels of TTS is highly unlikely. Since any hull-mounted sonar, such as
the SQS-53, engaged in anti-submarine warfare training would be moving
at between 10 and 15 kn (19-28 km/hr) and nominally pinging every 50
seconds, the vessel would have traveled a minimum distance of
approximately 257 m during the time between those pings. A scenario
could occur where an animal does not leave the vicinity of a ship or
travels a course parallel to the ship, however, the close distances
required make TTS exposure unlikely. For a Navy vessel moving at a
nominal 10 kn (19 km/hr), it is unlikely a marine mammal could maintain
speed parallel to the ship and receive adequate energy over successive
pings to suffer TTS.
In short, given the anticipated duration and levels of sound
exposure, we would not expect marine mammals to incur more than
relatively low levels of TTS (i.e., single digits of sensitivity loss).
To add context to this degree of TTS, individual marine mammals may
regularly experience variations of 6 dB differences in hearing
sensitivity across time (Finneran et al., 2000, 2002; Schlundt et al.,
2000).
3. Duration of TTS (recovery time)--In the TTS laboratory studies
(as discussed in the Potential Effects of Specified Activities on
Marine Mammals and their Habitat section), some using exposures of
almost an hour in duration or up to 217 SEL, almost all individuals
recovered within 1 day (or less, often in minutes), although in one
study (Finneran et al., 2007), recovery took 4 days.
Based on the range of degree and duration of TTS reportedly induced
by exposures to non-pulse sounds of energy higher than that to which
free-swimming marine mammals in the field are likely to be exposed
during MFAS/HFAS training exercises in the TMAA, it is unlikely that
marine mammals would ever sustain a TTS from MFAS that alters their
sensitivity by more than 20 dB for more than a few hours--and any
incident of TTS would likely be far less severe due to the short
duration of the majority of the events during the 21 days and the speed
of a typical vessel, especially given the fact that the higher power
sources resulting in TTS are predominantly intermittent, which have
been shown to result in shorter durations of TTS. Also, for the same
reasons discussed in the Preliminary Analysis and Negligible Impact
Determination--Diel Cycle section, and because of the short distance
within which animals would need to approach the sound source, it is
unlikely that animals would be exposed to the levels necessary to
induce TTS in subsequent time periods such that their recovery is
impeded. Additionally, though the frequency range of TTS that marine
mammals might sustain would overlap with some of the frequency ranges
of their vocalization types, the frequency range of TTS from MFAS would
not usually span the entire frequency range of one vocalization type,
much less span all types of vocalizations or other critical auditory
cues.
Tables 41 to 46 indicate the number of incidental takes by TTS for
each species or stock that are likely to result from the Navy's
activities. As a general point, the majority of these TTS takes are the
result of exposure to hull-
[[Page 49740]]
mounted MFAS (MF narrower band sources), with fewer from explosives
(broad-band lower frequency sources), and even fewer from HFAS sources
(narrower band). As described above, we expect the majority of these
takes to be in the form of mild (single-digit), short-term (minutes to
hours), narrower band (only affecting a portion of the animal's hearing
range) TTS. This means that for one to several times within the 21
days, for several minutes to maybe a few hours at most each, a taken
individual will have slightly diminished hearing sensitivity (slightly
more than natural variation, but nowhere near total deafness). More
often than not, such an exposure would occur within a narrower mid- to
higher frequency band that may overlap part (but not all) of a
communication, echolocation, or predator range, but sometimes across a
lower or broader bandwidth. The significance of TTS is also related to
the auditory cues that are germane within the time period that the
animal incurs the TTS. For example, if an odontocete has TTS at
echolocation frequencies, but incurs it at night when it is resting and
not feeding, it is not impactful. In short, the expected results of any
one of these limited number of mild TTS occurrences could be that (1)
it does not overlap signals that are pertinent to that animal in the
given time period, (2) it overlaps parts of signals that are important
to the animal, but not in a manner that impairs interpretation, or (3)
it reduces detectability of an important signal to a small degree for a
short amount of time--in which case the animal may be aware and be able
to compensate (but there may be slight energetic cost), or the animal
may have some reduced opportunities (e.g., to detect prey) or reduced
capabilities to react with maximum effectiveness (e.g., to detect a
predator or navigate optimally). However, given the small number of
times that any individual might incur TTS, the low degree of TTS and
the short anticipated duration, and the low likelihood that one of
these instances would occur in a time period in which the specific TTS
overlapped the entirety of a critical signal, it is unlikely that TTS
of the nature expected to result from the Navy activities would result
in behavioral changes or other impacts that would impact any
individual's (of any hearing sensitivity) reproduction or survival.
Auditory Masking or Communication Impairment
The ultimate potential impacts of masking on an individual (if it
were to occur) are similar to those discussed for TTS, but an important
difference is that masking only occurs during the time of the signal,
versus TTS, which continues beyond the duration of the signal.
Fundamentally, masking is referred to as a chronic effect because one
of the key harmful components of masking is its duration--the fact that
an animal would have reduced ability to hear or interpret critical cues
becomes much more likely to cause a problem the longer it is occurring.
Also inherent in the concept of masking is the fact that the potential
for the effect is only present during the times that the animal and the
source are in close enough proximity for the effect to occur (and
further, this time period would need to coincide with a time that the
animal was utilizing sounds at the masked frequency). As our analysis
has indicated, because of the relative movement of vessels and the
species involved in this rule, we do not expect the exposures with the
potential for masking to be of a long duration. In addition, masking is
fundamentally more of a concern at lower frequencies, because low
frequency signals propagate significantly further than higher
frequencies and because they are more likely to overlap both the
narrower LF calls of mysticetes, as well as many non-communication cues
such as fish and invertebrate prey, and geologic sounds that inform
navigation (although the Navy proposes no LFAS use for the activities
in this rulemaking). Masking is also more of a concern from continuous
sources (versus intermittent sonar signals) where there is no quiet
time between pulses within which auditory signals can be detected and
interpreted. For these reasons, dense aggregations of, and long
exposure to, continuous LF activity are much more of a concern for
masking, whereas comparatively short-term exposure to the predominantly
intermittent pulses of often narrow frequency range MFAS or HFAS, or
explosions are not expected to result in a meaningful amount of
masking. While the Navy occasionally uses LF and more continuous
sources (although, as noted above, the Navy proposes no LFAS use for
the activities in this rulemaking), it is not in the contemporaneous
aggregate amounts that would accrue to a masking concern. Specifically,
the nature of the activities and sound sources used by the Navy do not
support the likelihood of a level of masking accruing that would have
the potential to affect reproductive success or survival. Additional
detail is provided below.
Standard hull-mounted MFAS typically pings every 50 seconds. Some
hull-mounted anti-submarine sonars can also be used in an object
detection mode known as ``Kingfisher'' mode (e.g., used on vessels when
transiting to and from port) where pulse length is shorter but pings
are much closer together in both time and space since the vessel goes
slower when operating in this mode (note also that the duty cycle for
MF11 and MF12 sources is greater than 80 percent). For the majority of
other sources, the pulse length is significantly shorter than hull-
mounted active sonar, on the order of several microseconds to tens of
milliseconds. Some of the vocalizations that many marine mammals make
are less than one second long, so, for example with hull-mounted sonar,
there would be a 1 in 50 chance (only if the source was in close enough
proximity for the sound to exceed the signal that is being detected)
that a single vocalization might be masked by a ping. However, when
vocalizations (or series of vocalizations) are longer than one second,
masking would not occur. Additionally, when the pulses are only several
microseconds long, the majority of most animals' vocalizations would
not be masked.
Most ASW sonars and countermeasures use MF frequencies and a few
use HF frequencies. Most of these sonar signals are limited in the
temporal, frequency, and spatial domains. The duration of most
individual sounds is short, lasting up to a few seconds each. A few
systems operate with higher duty cycles or nearly continuously, but
they typically use lower power, which means that an animal would have
to be closer, or in the vicinity for a longer time, to be masked to the
same degree as by a higher level source. Nevertheless, masking could
occasionally occur at closer ranges to these high-duty cycle and
continuous active sonar systems, but as described previously, it would
be expected to be of a short duration when the source and animal are in
close proximity. While data are limited on behavioral responses of
marine mammals to continuously active sonars (Isojunno et al., 2020),
mysticete species are known to be able to habituate to novel and
continuous sounds (Nowacek et al., 2004), suggesting that they are
likely to have similar responses to high-duty cycle sonars.
Furthermore, most of these systems are hull-mounted on surface ships
with the ships moving at least 10 kn (19 km/hr), and it is unlikely
that the ship and the marine mammal would continue to move in the same
direction and the marine mammal subjected to the same exposure due to
that movement. Most ASW activities are
[[Page 49741]]
geographically dispersed and last for only a few hours, often with
intermittent sonar use even within this period. Most ASW sonars also
have a narrow frequency band (typically less than one-third octave).
These factors reduce the likelihood of sources causing significant
masking. HF signals (above 10 kHz) attenuate more rapidly in the water
due to absorption than do lower frequency signals, thus producing only
a very small zone of potential masking. If masking or communication
impairment were to occur briefly, it would more likely be in the
frequency range of MFAS (the more powerful source), which overlaps with
some odontocete vocalizations (but few mysticete vocalizations);
however, it would likely not mask the entirety of any particular
vocalization, communication series, or other critical auditory cue,
because the signal length, frequency, and duty cycle of the MFAS/HFAS
signal does not perfectly resemble the characteristics of any single
marine mammal species' vocalizations.
Other sources used in Navy training that are not explicitly
addressed above, many of either higher frequencies (meaning that the
sounds generated attenuate even closer to the source) or lower amounts
of operation, are similarly not expected to result in masking. For the
reasons described here, any limited masking that could potentially
occur would be minor and short-term.
In conclusion, masking is more likely to occur in the presence of
broadband, relatively continuous noise sources such as from vessels,
however, the duration of temporal and spatial overlap with any
individual animal and the spatially separated sources that the Navy
uses would not be expected to result in more than short-term, low
impact masking that would not affect reproduction or survival.
PTS From Sonar Acoustic Sources and Explosives and Non-Auditory Tissue
Damage From Explosives
Tables 41 to 46 indicate the number of individuals of each species
or stock for which Level A harassment in the form of PTS resulting from
exposure to active sonar and/or explosives is estimated to occur. The
Northeast Pacific stock of fin whale, Alaska stock of Dall's porpoise,
and California stock of Northern elephant seal are the only stocks
which may incur PTS (from sonar and explosives). For all other species/
stocks only take by Level B harassment (behavioral disturbance and/or
TTS) is anticipated. No species/stocks have the potential to incur non-
auditory tissue damage from training activities.
Data suggest that many marine mammals would deliberately avoid
exposing themselves to the received levels of active sonar necessary to
induce injury by moving away from or at least modifying their path to
avoid a close approach. Additionally, in the unlikely event that an
animal approaches the sonar-emitting vessel at a close distance, NMFS
has determined that the mitigation measures (i.e., shutdown/powerdown
zones for active sonar) would typically ensure that animals would not
be exposed to injurious levels of sound. As discussed previously, the
Navy utilizes both aerial (when available) and passive acoustic
monitoring (during ASW exercises, passive acoustic detections are used
as a cue for Lookouts' visual observations when passive acoustic assets
are already participating in an activity) in addition to Lookouts on
vessels to detect marine mammals for mitigation implementation. As
discussed previously, the Navy utilized a post-modeling quantitative
assessment to adjust the take estimates based on avoidance and the
likely success of some portion of the mitigation measures. As is
typical in predicting biological responses, it is challenging to
predict exactly how avoidance and mitigation would affect the take of
marine mammals. Therefore, in conducting the post-modeling quantitative
assessment, the Navy erred on the side of caution in choosing a method
that would more likely still overestimate the take by PTS to some
degree. Nonetheless, these Level A harassment take numbers represent
the maximum number of instances in which marine mammals would be
reasonably expected to incur PTS, and we have analyzed them
accordingly.
If a marine mammal is able to approach a surface vessel within the
distance necessary to incur PTS in spite of the mitigation measures,
the likely speed of the vessel (nominally 10-15 kn (19-28 km/hr)) and
relative motion of the vessel would make it very difficult for the
animal to remain in range long enough to accumulate enough energy to
result in more than a mild case of PTS. As discussed previously in
relation to TTS, the likely consequences to the health of an individual
that incurs PTS can range from mild to more serious dependent upon the
degree of PTS and the frequency band it is in. The majority of any PTS
incurred as a result of exposure to Navy sources would be expected to
be in a narrow band in the 2-20 kHz range (resulting from the most
powerful hull-mounted sonar) and could overlap a small portion of the
communication frequency range of many odontocetes, whereas other marine
mammal groups have communication calls at lower frequencies. Regardless
of the frequency band, the more important point in this case is that
any PTS accrued as a result of exposure to Navy activities would be
expected to be of a small amount (single digits of dB hearing loss).
Permanent loss of some degree of hearing is a normal occurrence for
older animals, and many animals are able to compensate for the shift,
both in old age or at younger ages as the result of stressor exposure.
While a small loss of hearing sensitivity may include some degree of
energetic costs for compensating or may mean some small loss of
opportunities or detection capabilities, at the expected scale it would
be unlikely to impact behaviors, opportunities, or detection
capabilities to a degree that would interfere with reproductive success
or survival.
The Navy implements mitigation measures (described in the Proposed
Mitigation Measures section) during explosive activities, including
delaying detonations when a marine mammal is observed in the mitigation
zone. Nearly all explosive events would occur during daylight hours to
improve the sightability of marine mammals and thereby improve
mitigation effectiveness. Observing for marine mammals during the
explosive activities would include visual and passive acoustic
detection methods (when they are available and part of the activity)
before the activity begins, in order to cover the mitigation zones that
can range from 200 yd (182.9 m) to 2,500 yd (2,286 m) depending on the
source (e.g., explosive bombs; see Table 34 and Table 35). For all of
these reasons, the proposed mitigation measures associated with
explosives are expected to further ensure that no non-auditory tissue
damage occurs to any potentially affected species, and no species are
anticipated to incur non-auditory tissue damage during the period of
the proposed rule.
Group and Species-Specific Analyses
The maximum amount and type of incidental take of marine mammals
reasonably likely to occur and therefore proposed to be authorized from
exposures to sonar and other active acoustic sources and in-air
explosions at or above the water surface during the 7-year training
period are shown in Table 30. The vast majority of predicted exposures
(greater than 99 percent) are expected to be non-injurious Level B
harassment (TTS and behavioral disturbance) from acoustic and
[[Page 49742]]
explosive sources during training activities at relatively low received
levels. A small number of takes by Level A harassment (PTS only) are
predicted for three species (Dall's porpoise, fin whales, and Northern
elephant seals).
In the discussions below, the estimated takes by Level B harassment
represent instances of take, not the number of individuals taken (the
less frequent Level A harassment takes are far more likely to be
associated with separate individuals), and in some cases individuals
may be taken more than one time. Below, we compare the total take
numbers (including PTS, TTS, and behavioral disturbance) for species or
stocks to their associated abundance estimates to evaluate the
magnitude of impacts across the species and to individuals. Generally,
when an abundance percentage comparison is below 100, it means that
that percentage or less of the individuals would be affected (i.e.,
some individuals would not be taken at all), that the average for those
taken is one day per year, and that we would not expect any individuals
to be taken more than a few times during the 21 days per year. When it
is more than 100 percent, it means there would definitely be some
number of repeated takes of individuals. For example, if the percentage
is 300, the average would be each individual is taken on 3 days in a
year if all were taken, but it is more likely that some number of
individuals would be taken more than three times and some number of
individuals fewer or not at all. While it is not possible to know the
maximum number of days across which individuals of a stock might be
taken, in acknowledgement of the fact that it is more than the average,
for the purposes of this analysis, we assume a number approaching twice
the average. For example, if the percentage of take compared to the
abundance is 800, we estimate that some individuals might be taken as
many as 16 times. Those comparisons are included in the sections below.
To assist in understanding what this analysis means, we clarify a
few issues related to estimated takes and the analysis here. An
individual that incurs a PTS or TTS take may sometimes, for example,
also be subject to behavioral disturbance at the same time. As
described above in this section, the degree of PTS, and the degree and
duration of TTS, expected to be incurred from the Navy's activities are
not expected to impact marine mammals such that their reproduction or
survival could be affected. Similarly, data do not suggest that a
single instance in which an animal accrues PTS or TTS and is also
subjected to behavioral disturbance would result in impacts to
reproduction or survival. Alternately, we recognize that if an
individual is subjected to behavioral disturbance repeatedly for a
longer duration and on consecutive days, effects could accrue to the
point that reproductive success is jeopardized, although those sorts of
impacts are not expected to result from these activities. Accordingly,
in analyzing the number of takes and the likelihood of repeated and
sequential takes, we consider the total takes, not just the takes by
Level B harassment by behavioral disturbance, so that individuals
potentially exposed to both threshold shift and behavioral disturbance
are appropriately considered. The number of Level A harassment takes by
PTS are so low (and zero in most cases) compared to abundance numbers
that it is considered highly unlikely that any individual would be
taken at those levels more than once.
Occasional, milder behavioral reactions are unlikely to cause long-
term consequences for individual animals or populations, and even if
some smaller subset of the takes are in the form of a longer (several
hours or a day) and more severe response, if they are not expected to
be repeated over sequential days, impacts to individual fitness are not
anticipated. Nearly all studies and experts agree that infrequent
exposures of a single day or less are unlikely to impact an
individual's overall energy budget (Farmer et al., 2018; Harris et al.,
2017; King et al., 2015; NAS 2017; New et al., 2014; Southall et al.,
2007; Villegas-Amtmann et al., 2015).
If impacts to individuals are of a magnitude or severity such that
either repeated and sequential higher severity impacts occur (the
probability of this goes up for an individual the higher total number
of takes it has) or the total number of moderate to more severe impacts
increases substantially, especially if occurring across sequential
days, then it becomes more likely that the aggregate effects could
potentially interfere with feeding enough to reduce energy budgets in a
manner that could impact reproductive success via longer cow-calf
intervals, terminated pregnancies, or calf mortality. It is important
to note that these impacts would only accrue to females, which only
comprise a portion of the population (typically approximately 50
percent). Based on energetic models, it takes energetic impacts of a
significantly greater magnitude to cause the death of an adult marine
mammal, and females will always terminate a pregnancy or stop lactating
before allowing their health to deteriorate. Also, the death of an
adult female has significantly more impact on population growth rates
than reductions in reproductive success, while the death of an adult
male has very little effect on population growth rates. However, as
will be explained further in the sections below, the severity and
magnitude of takes expected to result from Navy activities in the TMAA
are such that energetic impacts of a scale that might affect
reproductive success are not expected to occur at all.
The analyses below in some cases address species collectively if
they occupy the same functional hearing group (i.e., low, mid, and
high-frequency cetaceans), share similar life history strategies, and/
or are known to behaviorally respond similarly to acoustic stressors.
Because some of these groups or species share characteristics that
inform the impact analysis similarly, it would be duplicative to repeat
the same analysis for each species. In addition, similar species
typically have the same hearing capabilities and behaviorally respond
in the same manner.
Thus, our analysis below considers the effects of the Navy's
activities on each affected species or stock even where discussion is
organized by functional hearing group and/or information is evaluated
at the group level. Where there are meaningful differences between a
species or stock that would further differentiate the analysis, they
are either described within the section or the discussion for those
species or stocks is included as a separate subsection. Specifically
below, we first provide broad discussion of the expected effects on the
mysticete, odontocete, and pinniped groups generally, and then
differentiate into further groups as appropriate.
Mysticetes
This section builds on the broader discussion above and brings
together the discussion of the different types and amounts of take that
different species and stocks would likely incur, the applicable
mitigation, and the status of the species and stocks to support the
preliminary negligible impact determinations for each species or stock.
We have described (earlier in this section) the unlikelihood of any
masking having effects that would impact the reproduction or survival
of any of the individual marine mammals affected by the Navy's
activities. We have also described above in the Potential Effects of
Specified Activities on Marine Mammals and their Habitat section the
unlikelihood of any habitat impacts having effects that would
[[Page 49743]]
impact the reproduction or survival of any of the individual marine
mammals affected by the Navy's activities. For mysticetes, there is no
predicted non-auditory tissue damage from explosives for any species,
and only two fin whales could be taken by PTS by exposure to in-air
explosions at or above the water surface. Much of the discussion below
focuses on the behavioral effects and the mitigation measures that
reduce the probability or severity of effects. Because there are
species-specific and stock-specific considerations, at the end of the
section we break out our findings on a species-specific and, for one
species, stock-specific basis.
In Table 41 below for mysticetes, we indicate for each species and
stock the total annual numbers of take by Level A harassment and Level
B harassment, and a number indicating the instances of total take as a
percentage of abundance.
Table 41--Annual Estimated Takes by Level B Harassment and Level A Harassment for Mysticetes and Number Indicating the Instances of Total Take as a
Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Instances of indicated types of incidental
take \1\
------------------------------------------------ Instances of
Level B harassment Level A Abundance total take as
Species Stock -------------------------------- harassment Total takes (NMFS SARs) percentage of
TTS (may also ---------------- \2\ abundance
Behavioral include
disturbance disturbance) PTS
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Pacific right whale......... Eastern North 1 2 0 3 31 9.7
Pacific.
Humpback whale.................... California, Oregon, 2 8 0 10 4,973 <1
& Washington.
Central North 11 68 0 79 10,103 <1
Pacific.
Western North \3\ 3 0 0 \3\ 3 1,107 <1
Pacific.
Blue whale........................ Central North 0 3 0 3 133 2.3
Pacific.
Eastern North 4 32 0 36 1,898 1.9
Pacific.
Fin whale......................... Northeast Pacific... 115 1,127 2 1,244 \4\ 3,168 39.3
Sei whale......................... Eastern North 3 34 0 37 519 7.1
Pacific.
Minke whale....................... Alaska.............. 6 44 0 50 \5\ 389 12.9
Gray whale........................ Eastern North \3\ 4 0 0 \3\ 4 26,960 <1
Pacific.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate
individuals, especially for behavioral disturbance.
\2\ Presented in the 2021 draft SARs or most recent SAR.
\3\ The Navy's Acoustic Effects Model estimated zero takes for each of these stocks. However, NMFS conservatively proposes to authorize take by Level B
harassment of one group of Western North Pacific humpback whale and one group of Eastern North Pacific gray whale. The annual take estimates reflect
the average group sizes of on- and off-effort survey sightings of humpback whale and gray whale (excluding an outlier of an estimated 25 gray whales
in one group) reported in Rone et al. (2017).
\4\ The SAR reports this stock abundance assessment as provisional and notes that it is an underestimate for the entire stock because it is based on
surveys which covered only a small portion of the stock's range.
\5\ The 2018 final SAR (most recent SAR) for the Alaska stock of minke whales reports the stock abundance as unknown because only a portion of the
stock's range has been surveyed. To be conservative, for this stock we report the smallest estimated abundance produced during recent surveys.
The majority of takes by harassment of mysticetes in the TMAA would
be caused by anti-submarine warfare (ASW) activities. Anti-submarine
activities include sources from the MFAS bin (which includes hull-
mounted sonar). They are high level, narrowband sources in the 1-10 kHz
range, which intersect what is estimated to be the most sensitive area
of hearing for mysticetes. They also are used in a large portion of
exercises (see Table 1 and Table 3). Most of the takes (88 percent)
from the MF1 bin in the TMAA would result from received levels between
166 and 178 dB SPL, while another 11 percent would result from exposure
between 160 and 166 dB SPL. For the remaining active sonar bin types,
the percentages are as follows: MF4 = 97 percent between 142 and 154 dB
SPL and MF5 = 97 percent between 118 and 142 dB SPL. For mysticetes,
exposure to explosives would result in comparatively smaller numbers of
takes by Level B harassment by behavioral disturbance (0-11 per stock)
and TTS takes (0-2 per stock). Based on this information, the majority
of the takes by Level B harassment by behavioral disturbance would be
expected to be of low to sometimes moderate severity and of a
relatively shorter duration. Exposure to explosives would also result
in two takes by Level A harassment by PTS of the Northeast Pacific
stock of fin whale. No mortality or serious injury and no Level A
harassment from non-auditory tissue damage from training activities is
anticipated or proposed for authorization for any species or stock.
Research and observations show that if mysticetes are exposed to
sonar or other active acoustic sources they may react in a number of
ways depending on the characteristics of the sound source, their
experience with the sound source, and whether they are migrating or on
seasonal feeding or breeding grounds. Behavioral reactions may include
alerting, breaking off feeding dives and surfacing, diving or swimming
away, or no response at all (DOD, 2017; Nowacek, 2007; Richardson,
1995; Southall et al., 2007). Overall, mysticetes have been observed to
be more reactive to acoustic disturbance when a noise source is located
directly on their migration route. Mysticetes disturbed while migrating
could pause their migration or route around the disturbance, while
males en route to breeding grounds have been shown to be less
responsive to disturbances. Although some may pause temporarily, they
would resume migration shortly after the exposure ends. Animals
disturbed while engaged in other activities such as feeding or
reproductive behaviors may be more likely to ignore or tolerate the
disturbance and continue their natural behavior patterns. Alternately,
adult females with calves may be more responsive to stressors.
As noted in the Potential Effects of Specified Activities on Marine
Mammals and Their Habitat section, while there are multiple examples
from behavioral response studies of odontocetes ceasing their feeding
dives when exposed to sonar pulses at certain levels, blue whales were
less likely to show a visible response to sonar exposures at certain
levels when feeding than when traveling. However, Goldbogen et al.
(2013) indicated some horizontal displacement of deep foraging blue
whales in response to
[[Page 49744]]
simulated MFAS. Southall et al. (2019b) observed that after exposure to
simulated and operational mid-frequency active sonar, more than 50
percent of blue whales in deep-diving states responded to the sonar,
while no behavioral response was observed in shallow-feeding blue
whales. Southall et al. (2019b) noted that the behavioral responses
they observed were generally brief, of low to moderate severity, and
highly dependent on exposure context (behavioral state, source-to-whale
horizontal range, and prey availability).
Richardson et al. (1995) noted that avoidance (temporary
displacement of an individual from an area) reactions are the most
obvious manifestations of disturbance in marine mammals. Avoidance is
qualitatively different from the startle or flight response, but also
differs in the magnitude of the response (i.e., directed movement, rate
of travel, etc.). Oftentimes avoidance is temporary, and animals return
to the area once the noise has ceased. Some mysticetes may avoid larger
activities as they move through an area, although the Navy's activities
do not typically use the same training locations day-after-day during
multi-day activities, except periodically in instrumented ranges, which
are not present in the GOA Study Area. Therefore, displaced animals
could return quickly after even a large activity or MTE is completed.
At most, only one MTE would occur per year (over a maximum of 21
days), and additionally, MF1 mid-frequency active sonar would be
prohibited from June 1 to September 30 within the North Pacific Right
Whale Mitigation Area. Explosives detonated below 10,000 ft. altitude
(including at the water surface) would be prohibited in the Continental
Shelf and Slope Mitigation Area, including in the portion that overlaps
the North Pacific Right Whale Mitigation Area. In the open waters of
the Gulf of Alaska, the use of Navy sonar and other active acoustic
sources is transient and would be unlikely to expose the same
population of animals repeatedly over a short period of time,
especially given the broader-scale movements of mysticetes and the 21-
day duration of the activities.
The implementation of procedural mitigation and the sightability of
mysticetes (due to their large size) would further reduce the potential
for a significant behavioral reaction or a threshold shift to occur
(i.e., shutdowns are expected to be successfully implemented), which is
reflected in the amount and type of incidental take that would be
anticipated to occur and is proposed for authorization. Level B
harassment by behavioral disturbance of mysticetes resulting from the
TMAA activities would likely be short-term and of low to sometimes
moderate severity, with no anticipated effect on reproduction or
survival of any individuals.
As noted previously, when an animal incurs a threshold shift, it
occurs in the frequency from that of the source up to one octave above.
This means that the vast majority of threshold shifts caused by Navy
sonar sources would typically occur in the range of 2-20 kHz (from the
1-10 kHz MF bin, though in a specific narrow band within this range as
the sources are narrowband), and if resulting from hull-mounted sonar,
would be in the range of 3.5-7 kHz. The majority of mysticete
vocalizations occur in frequencies below 1 kHz, which means that TTS
incurred by mysticetes would not interfere with conspecific
communication. Additionally, many of the other critical sounds that
serve as cues for navigation and prey (e.g., waves, fish,
invertebrates) occur below a few kHz, which means that detection of
these signals would not be inhibited by most threshold shift either.
When we look in ocean areas where the Navy has been intensively
training and testing with sonar and other active acoustic sources for
decades, there is no data suggesting any long-term consequences to
reproduction or survival rates of mysticetes from exposure to sonar and
other active acoustic sources.
All the mysticete species discussed in this section would benefit
from the procedural mitigation measures described earlier in the
Proposed Mitigation Measures section. Additionally, the Navy would
issue awareness messages prior to the start of TMAA training activities
to alert vessels and aircraft operating within the TMAA to the possible
presence of concentrations of large whales, including mysticetes,
especially when traversing on the continental shelf and slope where
densities of these species may be higher. To maintain safety of
navigation and to avoid interactions with marine mammals, the Navy
would instruct vessels to remain vigilant to the presence of large
whales that may be vulnerable to vessel strikes or potential impacts
from training activities. Further, the Navy would limit activities and
employ other measures in mitigation areas that would avoid or reduce
impacts to mysticetes. Where these mitigation areas are expected to
mitigate impacts to particular species or stocks (North Pacific right
whale, humpback whale, gray whale), they are discussed in detail below.
Below we compile and summarize the information that supports our
preliminary determinations that the Navy's activities would not
adversely affect any mysticete species or stock through effects on
annual rates of recruitment or survival.
North Pacific Right Whale (Eastern North Pacific Stock)
North Pacific right whales are listed as endangered under the ESA,
and this species is currently one of the most endangered whales in the
world (Clapham, 2016; NMFS, 2013, 2017; Wade et al., 2010). The current
population trend is unknown. ESA-designated critical habitat for the
North Pacific right whale is located in the western Gulf of Alaska off
Kodiak Island and in the southeastern Bering Sea/Bristol Bay area (Muto
et al., 2017; Muto et al., 2018b; Muto et al., 2020a); there is no
designated critical habitat for this species within the GOA Study Area.
North Pacific right whales are anticipated to be present in the GOA
Study Area year round, but are considered rare, with a potentially
higher density between June and September. A BIA for feeding (June
through September; Ferguson et al., 2015b) overlaps with the TMAA
portion of the GOA Study Area by approximately 2,051 km\2\
(approximately 7 percent of the feeding BIA and 1.4 percent of the
TMAA). This BIA does not overlap with any portion of the WMA. This
proposed rule includes a North Pacific Right Whale Mitigation Area and
Continental Shelf and Slope Mitigation Area, which both overlap with
the portion of the North Pacific right whale feeding BIA that overlaps
with the TMAA. From June 1 to September 30, Navy personnel will not use
surface ship hull-mounted MF1 mid-frequency active sonar during
training activities within the North Pacific Right Whale Mitigation
Area. Further, Navy personnel will not detonate explosives below 10,000
ft altitude (including at the water surface) during training at all
times in the Continental Shelf and Slope Mitigation Area (including in
the portion that overlaps the North Pacific Right Whale Mitigation
Area). These restrictions would reduce the severity of impacts to North
Pacific right whales by reducing interference in feeding that could
result in lost feeding opportunities or necessitate additional energy
expenditure to find other good foraging opportunities.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), only 3 instances of take by level B harassment
(2 TTS, and 1 behavioral disturbance) are estimated,
[[Page 49745]]
which equate to about 10 percent of the very small estimated abundance.
Given this very small estimate, repeated exposures of individuals are
not anticipated. Regarding the severity of individual takes by Level B
harassment by behavioral disturbance, we have explained that the
duration of any exposure is expected to be between minutes and hours
(i.e., relatively short) and the received sound levels largely below
172 dB with a small portion up to 184 dB (i.e., of a moderate or
sometimes lower level). Regarding the severity of TTS takes, they are
expected to be low-level, of short duration, and mostly not in a
frequency band that would be expected to interfere with North Pacific
right whale communication or other important low-frequency cues.
Therefore, the associated lost opportunities and capabilities are not
at a level that would impact reproduction or survival.
Altogether, North Pacific right whales are listed as endangered
under the ESA, and the current population trend is unknown. Only three
instances of take are estimated to occur (a small portion of the
stock), and any individual North Pacific right whale is likely to be
disturbed at a low-moderate level. This low magnitude and severity of
harassment effects is not expected to result in impacts on the
reproduction or survival of any individuals, let alone have impacts on
annual rates of recruitment or survival of this stock. No mortality or
Level A harassment is anticipated or proposed to be authorized. For
these reasons, we have preliminarily determined, in consideration of
all of the effects of the Navy's activities combined, that the proposed
authorized take would have a negligible impact on the Eastern North
Pacific stock of North Pacific right whales.
Humpback Whale (California/Oregon/Washington Stock)
The California/Oregon/Washington (CA/OR/WA) stock of humpback
whales includes individuals from three ESA DPSs: Central America
(endangered), Mexico (threatened), and Hawaii (not listed). A small
portion of ESA-designated critical habitat overlaps with the TMAA
portion of the GOA Study Area (see Figure 4-1 of the Navy's rulemaking/
LOA application). The ESA-designated critical habitat does not overlap
with any portion of the WMA. No other BIAs are identified for this
species in the GOA Study Area. The SAR identifies this stock as stable
(having shown a long-term increase from 1990 and then leveling off
between 2008 and 2014). Navy personnel will not use surface ship hull-
mounted MF1 mid-frequency active sonar from June 1 to September 30
within the North Pacific Right Whale Mitigation Area, which overlaps 18
percent of the humpback whale critical habitat in the TMAA. Further,
Navy personnel will not detonate explosives below 10,000 ft altitude
(including at the water surface) during training at all times in the
Continental Shelf and Slope Mitigation Area (including in the portion
that overlaps the North Pacific Right Whale Mitigation Area), which
fully overlaps the portion of the humpback whale critical habitat in
the TMAA. These measures would reduce the severity of impacts to
humpback whales by reducing interference in feeding that could result
in lost feeding opportunities or necessitate additional energy
expenditure to find other good opportunities.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), the number of estimated total instances of
take is 10 (8 TTS and 2 behavioral disturbance), which is less than 1
percent of the abundance. Given the very low number of anticipated
instances of take, only a very small portion of individuals in the
stock are likely impacted and repeated exposures of individuals are not
anticipated. Regarding the severity of those individual takes by Level
B harassment by behavioral disturbance, we have explained that the
duration of any exposure is expected to be between minutes and hours
(i.e., relatively short) and the received sound levels largely below
172 dB with a small portion up to 184 dB (i.e., of a moderate or
sometimes lower level). Regarding the severity of TTS takes, they are
expected to be low-level, of short duration, and mostly not in a
frequency band that would be expected to interfere with humpback whale
communication or other important low-frequency cues. Therefore, the
associated lost opportunities and capabilities are not at a level that
would impact reproduction or survival.
Altogether, this population is stable (even though two of the three
associated DPSs are listed as endangered or threatened under the ESA),
only a very small portion of the stock is anticipated to be impacted,
and any individual humpback whale is likely to be disturbed at a low-
moderate level. No mortality or serious injury and no Level A
harassment is anticipated or proposed to be authorized. This low
magnitude and severity of harassment effects is not expected to result
in impacts on the reproduction or survival of any individuals, let
alone have impacts on annual rates of recruitment or survival of this
stock. For these reasons, we have preliminarily determined, in
consideration of all of the effects of the Navy's activities combined,
that the proposed authorized take would have a negligible impact on the
CA/OR/WA stock of humpback whales.
Humpback Whale (Central North Pacific Stock)
The Central North Pacific stock of humpback whales consists of
winter/spring humpback whale populations of the Hawaiian Islands which
migrate primarily to foraging habitat in northern British Columbia/
Southeast Alaska, the Gulf of Alaska, and the Bering Sea/Aleutian
Islands. The population is increasing (Muto et al. 2020), the Hawaii
DPS is not ESA-listed, and no BIAs have been identified for this
species in the GOA Study Area. Navy personnel will not use surface ship
hull-mounted MF1 mid-frequency active sonar from June 1 to September 30
within the North Pacific Right Whale Mitigation Area, which overlaps 18
percent of the humpback whale critical habitat within the TMAA. As
noted above, the Hawaii DPS is not ESA-listed; however, this ESA-
designated critical habitat still indicates the likely value of habitat
in this area to non-listed humpback whales. Further, Navy personnel
will not detonate explosives below 10,000 ft altitude (including at the
water surface) during training at all times in the Continental Shelf
and Slope Mitigation Area (including in the portion that overlaps the
North Pacific Right Whale Mitigation Area), which fully overlaps the
portion of the humpback whale critical habitat in the TMAA. These
measures would reduce the severity of impacts to humpback whales by
reducing interference in feeding that could result in lost feeding
opportunities or necessitate additional energy expenditure to find
other good opportunities.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), the number of estimated instances of take
compared to the abundance is less than 1 percent. This information and
the complicated far-ranging nature of the stock structure indicates
that only a very small portion of the stock is likely impacted. While
no BIAs have been identified in the GOA Study Area, highest densities
in the nearby Kodiak Island feeding BIA (July to September) and Prince
William Sound feeding BIA (September to December) overlap with much of
the potential window for the Navy's exercise in the GOA Study Area
(April to October). Given that some whales
[[Page 49746]]
may remain in the area surrounding these BIAs for some time to feed
during the Navy's exercise, there may be a few repeated exposures of a
few individuals, most likely on non-sequential days. Regarding the
severity of those individual takes by Level B harassment by behavioral
disturbance, we have explained that the duration of any exposure is
expected to be between minutes and hours (i.e., relatively short) and
the received sound levels largely below 172 dB with a small portion up
to 184 dB (i.e., of a moderate or sometimes lower level). Regarding the
severity of TTS takes, they are expected to be low-level, of short
duration, and mostly not in a frequency band that would be expected to
interfere with humpback whale communication or other important low-
frequency cues. Therefore, the associated lost opportunities and
capabilities are not at a level that would impact reproduction or
survival.
Altogether, this population is increasing and the associated DPS is
not listed as endangered or threatened under the ESA. Only a very small
portion of the stock is anticipated to be impacted and any individual
humpback whale is likely to be disturbed at a low-moderate level. This
low magnitude and severity of harassment effects is not expected to
result in impacts on individual reproduction or survival, let alone
have impacts on annual rates of recruitment or survival of this stock.
No mortality or Level A harassment is anticipated or proposed to be
authorized. For these reasons, we have preliminarily determined, in
consideration of all of the effects of the Navy's activities combined,
that the proposed authorized take would have a negligible impact on the
Central North Pacific stock of humpback whales.
Humpback Whale (Western North Pacific Stock)
The Western North Pacific stock of humpback whales includes
individuals from the Western North Pacific DPS, which is ESA-listed as
endangered. A relatively small portion of ESA-designated critical
habitat overlaps with the TMAA (2,708 km\2\ (1,046 mi\2\) of critical
habitat Unit 5, 5,991 km\2\ (2,313 mi\2\) of critical habitat Unit 8;
see Figure 4-1 of the Navy's rulemaking/LOA application). The ESA-
designated critical habitat does not overlap with any portion of the
WMA. No other BIAs are identified for this species in the GOA Study
Area. The current population trend for this stock is unknown. Navy
personnel will not use surface ship hull-mounted MF1 mid-frequency
active sonar from June 1 to September 30 within the North Pacific Right
Whale Mitigation Area, which overlaps 18 percent of the humpback whale
critical habitat within the TMAA. Further, Navy personnel will not
detonate explosives below 10,000 ft altitude (including at the water
surface) during training at all times in the Continental Shelf and
Slope Mitigation Area (including in the portion that overlaps the North
Pacific Right Whale Mitigation Area), which fully overlaps the portion
of the humpback whale critical habitat in the TMAA. These measures
would reduce the severity of impacts to humpback whales by reducing
interference in feeding that could result in lost feeding opportunities
or necessitate additional energy expenditure to find other good
opportunities.
Regarding the magnitude of takes by Level B harassment (behavioral
disturbance only), the number of estimated total instances of take is
three, which is less than 1 percent of the abundance. Given the very
low number of anticipated instances of take, only a very small portion
of individuals in the stock are likely impacted and repeated exposures
of individuals are not anticipated. Regarding the severity of those
individual takes by Level B harassment by behavioral disturbance, we
have explained that the duration of any exposure is expected to be
between minutes and hours (i.e., relatively short) and the received
sound levels largely below 172 dB with a small portion up to 184 dB
(i.e., of a moderate or sometimes lower level).
Altogether, the status of this stock is unknown, only a very small
portion of the stock is anticipated to be impacted (3 individuals), and
any individual humpback whale is likely to be disturbed at a low-
moderate level. No mortality, serious injury, Level A harassment, or
TTS is anticipated or proposed to be authorized. This low magnitude and
severity of harassment effects is not expected to result in impacts on
the reproduction or survival of any individuals, let alone have impacts
on annual rates of recruitment or survival of this stock. For these
reasons, we have preliminarily determined, in consideration of all of
the effects of the Navy's activities combined, that the proposed
authorized take would have a negligible impact on the Western North
Pacific stock of humpback whales.
Blue Whale (Central North Pacific Stock and Eastern North Pacific
Stock)
Blue whales are listed as endangered under the ESA throughout their
range, but there is no ESA designated critical habitat and no BIAs have
been identified for this species in the GOA Study Area. The current
population trend for the Central North Pacific stock is unknown, and
the Eastern North Pacific stock is stable.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), the number of estimated total instances of
take compared to the abundance is 2 percent for both the Central North
Pacific stock, and the Eastern North Pacific stock. For the Central
North Pacific stock, only 3 instances of take (TTS) are anticipated.
Given the range of both blue whale stocks, the absence of any known
feeding or aggregation areas, and the very low number of anticipated
instances of take of the Central North Pacific stock, this information
indicates that only a small portion of individuals in the stock are
likely impacted and repeated exposures of individuals are not
anticipated. Regarding the severity of those individual takes by Level
B harassment by behavioral disturbance, we have explained that the
duration of any exposure is expected to be between minutes and hours
(i.e., relatively short) and the received sound levels largely below
172 dB with a small portion up to 184 dB (i.e., of a moderate or
sometimes lower level). Regarding the severity of TTS takes, we have
explained that they are expected to be low-level, of short duration,
and mostly not in a frequency band that would be expected to interfere
with blue whale communication or other important low-frequency cues.
Therefore, the associated lost opportunities and capabilities are not
at a level that would impact reproduction or survival.
Altogether, blue whales are listed as endangered under the ESA
throughout their range, the current population trend for the Central
North Pacific stock is unknown, and the Eastern North Pacific stock is
stable. Only a small portion of the stocks are anticipated to be
impacted, and any individual blue whale is likely to be disturbed at a
low-moderate level. The low magnitude and severity of harassment
effects is not expected to result in impacts on the reproduction or
survival of any individuals, let alone have impacts on annual rates of
recruitment or survival of this stock. No mortality and no Level A
harassment is anticipated or proposed for authorization. For these
reasons, we have preliminarily determined, in consideration of all of
the effects of the Navy's activities combined, that the proposed
authorized take would have a negligible impact on the Central North
Pacific stock and the Eastern North Pacific stock of blue whales.
[[Page 49747]]
Fin Whale (Northeast Pacific Stock)
Fin whales are listed as endangered under the ESA throughout their
range, but there is no ESA designated critical habitat and no BIAs have
been identified for this species in the GOA Study Area. The SAR
identifies this stock as increasing.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), the number of estimated total instances of
take compared to the abundance is 39 percent (though, as noted in Table
41, the SAR reports the stock abundance assessment as provisional and
notes that it is an underestimate for the entire stock because it is
based on surveys which covered only a small portion of the stock's
range, and therefore 39 percent is likely an overestimate). Given the
large range of the stock and short duration of the Navy's activities in
the GOA Study Area, this information suggests that notably fewer than
half of the individuals of the stock would likely be impacted, and that
most affected individuals would likely be disturbed on a few days
within the 21-day exercise, with the days most likely being non-
sequential. Regarding the severity of those individual takes by Level B
harassment by behavioral disturbance, we have explained that the
duration of any exposure is expected to be between minutes and hours
(i.e., relatively short) and the received sound levels largely below
172 dB with a small portion up to 184 dB (i.e., of a moderate or
sometimes lower level). Regarding the severity of TTS takes, they are
expected to be low-level, of short duration, and mostly not in a
frequency band that would be expected to interfere with fin whale
communication or other important low-frequency cues. Therefore, the
associated lost opportunities and capabilities are not at a level that
would impact reproduction or survival.
For these same reasons (low level and frequency band), while a
small permanent loss of hearing sensitivity (PTS) may include some
degree of energetic costs for compensating or may mean some small loss
of opportunities or detection capabilities, at the expected scale the
estimated two takes by Level A harassment by PTS would be unlikely to
impact behaviors, opportunities, or detection capabilities to a degree
that would interfere with reproductive success or survival of those
individuals. Thus, the two takes by Level A harassment by PTS would be
unlikely to affect rates of recruitment and survival for the stock.
Altogether, fin whales are listed as endangered under the ESA,
though this population is increasing. Only a small portion of the stock
is anticipated to be impacted, and any individual fin whale is likely
to be disturbed at a low-moderate level. This low magnitude and
severity of harassment effects is not expected to result in impacts on
reproduction or survival of any individuals, let alone have impacts on
annual rates of recruitment or survival of this stock. No mortality or
serious injury and no Level A harassment from non-auditory tissue
damage is anticipated or proposed for authorization. For these reasons,
we have preliminarily determined, in consideration of all of the
effects of the Navy's activities combined, that the proposed authorized
take would have a negligible impact on the Northeast Pacific stock of
fin whales.
Sei Whale (Eastern North Pacific Stock)
The population trend of this stock is unknown, however sei whales
are listed as endangered under the ESA throughout their range. There is
no ESA designated critical habitat and no BIAs have been identified for
this species in the GOA Study Area.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), the number of estimated total instances of
take compared to the abundance is 7 percent. This information and the
rare occurrence of sei whales in the TMAA suggests that only a small
portion of individuals in the stock would likely be impacted and
repeated exposures of individuals would not be anticipated. Regarding
the severity of those individual takes by Level B harassment by
behavioral disturbance, we have explained that the duration of any
exposure is expected to be between minutes and hours (i.e., relatively
short) and the received sound levels largely below 172 dB with a small
portion up to 184 dB (i.e., of a moderate or sometimes lower level).
Regarding the severity of TTS takes, they are expected to be low-level,
of short duration, and mostly not in a frequency band that would be
expected to interfere with sei whale communication or other important
low-frequency cues. Therefore, the associated lost opportunities and
capabilities are not at a level that would impact reproduction or
survival.
Altogether, the status of the stock is unknown and the species is
listed as endangered, only a small portion of the stock is anticipated
to be impacted, and any individual sei whale is likely to be disturbed
at a low-moderate level. This low magnitude and severity of harassment
effects is not expected to result in impacts on individual reproduction
or survival, much less annual rates of recruitment or survival. No
mortality and no Level A harassment is anticipated or proposed for
authorization. For these reasons, we have preliminarily determined, in
consideration of all of the effects of the Navy's activities combined,
that the proposed authorized take would have a negligible impact on the
Eastern North Pacific stock of sei whales.
Minke Whale (Alaska Stock)
The status of this stock is unknown and the species is not listed
under the ESA. No BIAs have been identified for this species in the GOA
Study Area.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), the number of estimated total instances of
take compared to the abundance is 13 percent for the Alaska stock
(based on, to be conservative, the smallest available provisional
estimate in the SAR, which is derived from surveys that cover only a
portion of the stock's range). Given the range of the Alaska stock of
minke whales, this information indicates that only a small portion of
individuals in this stock are likely to be impacted and repeated
exposures of individuals are not anticipated. Regarding the severity of
those individual takes by Level B harassment by behavioral disturbance,
we have explained that the duration of any exposure is expected to be
between minutes and hours (i.e., relatively short) and the received
sound levels largely below 172 dB with a small portion up to 184 dB
(i.e., of a moderate or sometimes lower level). Regarding the severity
of TTS takes, they are expected to be low-level, of short duration, and
mostly not in a frequency band that would be expected to interfere with
minke whale communication or other important low-frequency cues.
Therefore, the associated lost opportunities and capabilities are not
at a level that would impact reproduction or survival.
Altogether, although the status of the stock is unknown, the
species is not listed under the ESA as endangered or threatened, only a
small portion of the stock is anticipated to be impacted, and any
individual minke whale is likely to be disturbed at a low-moderate
level. This low magnitude and severity of harassment effects is not
expected to result in impacts on individual reproduction or survival,
let alone have impacts on annual rates of recruitment or survival of
this stock. No mortality, serious injury, or Level A harassment is
anticipated or proposed to be
[[Page 49748]]
authorized. For these reasons, we have preliminarily determined, in
consideration of all of the effects of the Navy's activities combined,
that the proposed authorized take would have a negligible impact on the
Alaska stock of minke whales.
Gray Whale (Eastern North Pacific Stock)
The Eastern North Pacific stock of gray whale is not ESA-listed,
and the SAR indicates that the stock is increasing. The TMAA portion of
the GOA Study Area overlaps with a gray whale migration corridor that
has been identified as a BIA (November-January (outside of the
potential training window), southbound; March-May, northbound; Ferguson
et al., 2015). The WMA portion of the GOA Study Area does not overlap
with any known important areas for gray whales.
Regarding the magnitude of takes by Level B harassment (behavioral
disturbance only), the number of estimated total instances of take is
four, which is less than 1 percent of the abundance. Given the very low
number of anticipated instances of take, only a very small portion of
individuals in the stock are likely impacted and repeated exposures of
individuals are not anticipated. Regarding the severity of those
individual takes by Level B harassment by behavioral disturbance, we
have explained that the duration of any exposure is expected to be
between minutes and hours (i.e., relatively short) and the received
sound levels largely below 172 dB with a small portion up to 184 dB
(i.e., of a moderate or sometimes lower level).
Altogether, while we have considered the impacts of the gray whale
UME, this population of gray whales is not endangered or threatened
under the ESA, and the stock is increasing. No mortality, Level A
harassment, or TTS is anticipated or proposed to be authorized. Only a
very small portion of the stock is anticipated to be impacted, and any
individual gray whale is likely to be disturbed at a low-moderate
level. This low magnitude and severity of harassment effects is not
expected to result in impacts on the reproduction or survival of any
individuals, let alone have impacts on annual rates of recruitment or
survival of this stock. For these reasons, we have preliminarily
determined, in consideration of all of the effects of the Navy's
activities combined, that the proposed authorized take would have a
negligible impact on the Eastern North Pacific stock of gray whales.
Odontocetes
This section builds on the broader discussion above and brings
together the discussion of the different types and amounts of take that
different species and stocks would likely incur, the applicable
mitigation, and the status of the species and stocks to support the
negligible impact determinations for each species or stock. We have
described (earlier in this section) the unlikelihood of any masking
having effects that would impact the reproduction or survival of any of
the individual marine mammals affected by the Navy's activities. We
have also described above in the Potential Effects of Specified
Activities on Marine Mammals and their Habitat section the unlikelihood
of any habitat impacts having effects that would impact the
reproduction or survival of any of the individual marine mammals
affected by the Navy's activities. There is no predicted PTS from sonar
or explosives for most odontocetes, with the exception of Dall's
porpoise, which is discussed below. There is no anticipated M/SI or
non-auditory tissue damage from sonar or explosives for any species.
Here, we include information that applies to all of the odontocete
species, which are then further divided and discussed in more detail in
the following subsections: sperm whales; beaked whales; dolphins and
small whales; and porpoises. These subsections include more specific
information about the groups, as well as conclusions for each species
or stock represented.
The majority of takes by harassment of odontocetes in the TMAA are
caused by sources from the MFAS bin (which includes hull-mounted sonar)
because they are high level, typically narrowband sources at a
frequency (in the 1-10 kHz range) that overlaps a more sensitive
portion (though not the most sensitive) of the MF hearing range and
they are used in a large portion of exercises (see Table 1 and Table
3). For odontocetes other than beaked whales (for which these
percentages are indicated separately in that section), most of the
takes (95 percent) from the MF1 bin in the TMAA would result from
received levels between 160 and 172 dB SPL. For the remaining active
sonar bin types, the percentages are as follows: MF4 = 98 percent
between 142 and 160 dB SPL and MF5 = 94 percent between 118 and 142 dB
SPL. Based on this information, the majority of the takes by Level B
harassment by behavioral disturbance are expected to be low to
sometimes moderate in nature, but still of a generally shorter
duration.
For all odontocetes, takes from explosives (Level B harassment by
behavioral disturbance, TTS, or PTS) comprise a very small fraction
(and low number) of those caused by exposure to active sonar. For the
following odontocetes, zero takes from explosives are expected to
occur: sperm whale, killer whale, Pacific white-sided dolphin, Baird's
beaked whale, and Stejneger's beaked whale. For Level B harassment by
behavioral disturbance from explosives, one take is anticipated for
Cuvier's beaked whale and 38 takes are anticipated for Dall's porpoise.
No TTS or PTS is expected to occur from explosives for any stocks
except Dall's porpoise. Because of the lower TTS and PTS thresholds for
HF odontocetes, the Alaska stock of Dall's porpoise is expected to have
229 takes by TTS and 45 takes by PTS from explosives.
Because the majority of harassment takes of odontocetes result from
the sources in the MFAS bin, the vast majority of threshold shift would
occur at a single frequency within the 1-10 kHz range and, therefore,
the vast majority of threshold shift caused by Navy sonar sources would
be at a single frequency within the range of 2-20 kHz. The frequency
range within which any of the anticipated narrowband threshold shift
would occur would fall directly within the range of most odontocete
vocalizations (2-20 kHz) (though phocoenids generally communicate at
higher frequencies (Soerensen et al., 2018; Clausen et al. 2010), which
would not be impacted by this threshold shift). For example, the most
commonly used hull-mounted sonar has a frequency around 3.5 kHz, and
any associated threshold shift would be expected to be at around 7 kHz.
However, odontocete vocalizations typically span a much wider range
than this, and alternately, threshold shift from active sonar will
often be in a narrower band (reflecting the narrower band source that
caused it), which means that TTS incurred by odontocetes would
typically only interfere with communication within a portion of their
hearing range (if it occurred during a time when communication with
conspecifics was occurring) and, as discussed earlier, it would only be
expected to be of a short duration and relatively small degree.
Odontocete echolocation occurs predominantly at frequencies
significantly higher than 20 kHz (though there may be some small
overlap at the lower part of their echolocating range for some
species), which means that there is little likelihood that threshold
shift, either temporary or permanent, would interfere with feeding
behaviors.
[[Page 49749]]
Many of the other critical sounds that serve as cues for navigation and
prey (e.g., waves, fish, invertebrates) occur below a few kHz, which
means that detection of these signals will not be inhibited by most
threshold shift either. The low number of takes by threshold shift that
might be incurred by individuals exposed to explosives would likely be
lower frequency (5 kHz or less) and spanning a wider frequency range,
which could slightly lower an individual's sensitivity to navigational
or prey cues, or a small portion of communication calls, for several
minutes to hours (if temporary) or permanently. There is no reason to
think that the vast majority of the individual odontocetes taken by TTS
would incur TTS on more than one day, although a small number could
incur TTS on a few days at most. Therefore, odontocetes are unlikely to
incur impacts on reproduction or survival as a result of TTS. PTS takes
from these sources are very low (0 for all species other than Dall's
porpoise), and while spanning a wider frequency band, are still
expected to be of a low degree (i.e., low amount of hearing sensitivity
loss) and unlikely to affect reproduction or survival.
The range of potential behavioral effects of sound exposure on
marine mammals generally, and odontocetes specifically, has been
discussed in detail previously. There are behavioral patterns that
differentiate the likely impacts on odontocetes as compared to
mysticetes however. First, odontocetes echolocate to find prey, which
means that they actively send out sounds to detect their prey. While
there are many strategies for hunting, one common pattern, especially
for deeper diving species, is many repeated deep dives within a bout,
and multiple bouts within a day, to find and catch prey. As discussed
above, studies demonstrate that odontocetes may cease their foraging
dives in response to sound exposure. If enough foraging interruptions
occur over multiple sequential days, and the individual either does not
take in the necessary food, or must exert significant effort to find
necessary food elsewhere, energy budget deficits can occur that could
potentially result in impacts to reproductive success, such as
increased cow/calf intervals (the time between successive calving).
However, the relatively low impact of the Navy's activities on
odontocetes in the TMAA indicate this is not likely to occur. Second,
while many mysticetes rely on seasonal migratory patterns that position
them in a geographic location at a specific time of the year to take
advantage of ephemeral large abundances of prey (i.e., invertebrates or
small fish, which they eat by the thousands), odontocetes forage more
homogeneously on one fish or squid at a time. Therefore, if odontocetes
are interrupted while feeding, it is often possible to find more prey
relatively nearby.
All the odontocete species and stocks discussed in this section
would benefit from the procedural mitigation measures described earlier
in the Proposed Mitigation Measures section.
Sperm Whale (North Pacific Stock)
This section builds on the broader odontocete discussion above and
brings together the discussion of the different types and amounts of
take that sperm whales would likely incur, the applicable mitigation,
and the status of the species/stock to support the preliminary
negligible impact determination for the stock.
Sperm whales are listed as endangered under the ESA. No critical
habitat has been designated for sperm whales under the ESA and no BIAs
for sperm whales have been identified in the GOA Study Area. The
stock's current population trend is unknown. The Navy would issue
awareness messages prior to the start of TMAA training activities to
alert Navy ships and aircraft operating within the TMAA to the possible
presence of increased concentrations of large whales, including sperm
whales. This measure would further reduce any possibility of ship
strike of sperm whales.
In Table 42 below for sperm whales, we indicate the total annual
numbers of take by Level A harassment and Level B harassment, and a
number indicating the instances of total take as a percentage of
abundance.
Table 42--Annual Estimated Takes by Level B Harassment and Level A Harassment for Sperm Whales in the TMAA and Number Indicating the Instances of Total
Take as a Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Instances of indicated types of incidental
take\1\
--------------------------------------------------- Instances of
Level B harassment Level A Abundance (NMFS total take as
Species Stock ---------------------------------- harassment Total takes SARs)\2\ percentage of
TTS (may also ----------------- abundance
Behavioral include
disturbance disturbance) PTS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale.................... North Pacific.... 107 5 0 112 \3\ 345 32.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate
individuals, especially for disturbance.
\2\ Presented in the 2021 draft SARs or most recent SAR.
\3\ The SAR reports that this is an underestimate for the entire stock because it is based on surveys of a small portion of the stock's extensive range
and it does not account for animals missed on the trackline or for females and juveniles in tropical and subtropical waters.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), the number of estimated total instances of
take compared to the abundance is 33 percent. Given the range of this
stock, this information indicates that fewer than half of the
individuals in the stock are likely to be impacted, with those
individuals disturbed on likely one, but not more than a few non-
sequential days within the 21 days per year. Additionally, while
interrupted feeding bouts are a known response and concern for
odontocetes, we also know that there are often viable alternative
habitat options in the relative vicinity. Regarding the severity of
those individual takes by Level B harassment by behavioral disturbance,
we have explained that the duration of any exposure is expected to be
between minutes and hours (i.e., relatively short) and the received
sound levels largely below 172 dB (i.e., of a lower, to occasionally
moderate, level and less likely to evoke a severe response). As
discussed earlier in the Preliminary Analysis and Negligible Impact
Determination section, we anticipate more severe effects from takes
when animals are exposed to higher received levels or for longer
durations. Occasional milder Level B harassment
[[Page 49750]]
by behavioral disturbance, as is expected here, is unlikely to cause
long-term consequences for either individual animals or populations,
even if some smaller subset of the takes are in the form of a longer
(several hours or a day) and more moderate response. Regarding the
severity of TTS takes, they are expected to be low-level, of short
duration, and mostly not in a frequency band that would be expected to
interfere with sperm whale communication or other important low-
frequency cues. Therefore, the associated lost opportunities and
capabilities are not at a level that would impact reproduction or
survival.
Altogether, sperm whales are listed as endangered under the ESA,
and the current population trend is unknown. Fewer than half of the
individuals of the stock are anticipated to be impacted, and any
individual sperm whale is likely to be disturbed at a low-moderate
level. This low magnitude and severity of harassment effects is not
expected to result in impacts on reproduction or survival for any
individuals, let alone have impacts on annual rates of recruitment or
survival of this stock. No mortality, serious injury, or Level A
harassment is anticipated or proposed to be authorized. For these
reasons, we have preliminarily determined, in consideration of all of
the effects of the Navy's activities combined, that the proposed
authorized take would have a negligible impact on the North Pacific
stock of sperm whales.
Beaked Whales
This section builds on the broader odontocete discussion above and
brings together the discussion of the different types and amounts of
take that different beaked whale species and stocks would likely incur,
the applicable mitigation, and the status of the species and stocks to
support the preliminary negligible impact determinations for each
species or stock. For beaked whales, no mortality or Level A harassment
is anticipated or proposed for authorization.
In Table 43 below for beaked whales, we indicate the total annual
numbers of take by Level A harassment and Level B harassment, and a
number indicating the instances of total take as a percentage of
abundance.
Table 43--Annual Estimated Takes by Level B Harassment and Level A Harassment for Beaked Whales in the TMAA and Number Indicating the Instances of Total
Take as a Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Instances of indicated types of incidental
take\1\
------------------------------------------------ Instances of
Level B harassment Level A Abundance total take as
Species Stock -------------------------------- harassment Total takes (NMFS SARs)\2\ percentage of
TTS (may also ---------------- abundance
Behavioral include
disturbance disturbance) PTS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baird's beaked whale.............. Alaska.............. 106 0 0 106 NA NA
Cuvier's beaked whale............. Alaska.............. 430 3 0 433 NA NA
Stejneger's beaked whale.......... Alaska.............. 467 15 0 482 NA NA
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate
individuals, especially for disturbance.
\2\ Reliable estimates of abundance for these stocks are currently unavailable.
This first paragraph provides specific information that is in lieu
of the parallel information provided for odontocetes as a whole. The
majority of takes by harassment of beaked whales in the TMAA would be
caused by sources from the MFAS bin (which includes hull-mounted sonar)
because they are high level narrowband sources that fall within the 1-
10 kHz range, which overlap a more sensitive portion (though not the
most sensitive) of the MF hearing range. Also, of the sources expected
to result in take, they are used in a large portion of exercises (see
Table 1 and Table 3). Most of the takes (98 percent) from the MF1 bin
in the TMAA would result from received levels between 148 and 166 dB
SPL. For the remaining active sonar bin types, the percentages are as
follows: MF4 = 97 percent between 130 and 148 dB SPL and MF5 = 99
percent between 100 and 148 dB SPL. Given the levels they are exposed
to and beaked whale sensitivity, some responses would be of a lower
severity, but many would likely be considered moderate, but still of
generally short duration.
Research has shown that beaked whales are especially sensitive to
the presence of human activity (Pirotta et al., 2012; Tyack et al.,
2011) and therefore have been assigned a lower harassment threshold,
with lower received levels resulting in a higher percentage of
individuals being harassed and a more distant distance cutoff (50 km
for high source level, 25 km for moderate source level).
Beaked whales have been documented to exhibit avoidance of human
activity or respond to vessel presence (Pirotta et al., 2012). Beaked
whales were observed to react negatively to survey vessels or low
altitude aircraft by quick diving and other avoidance maneuvers, and
none were observed to approach vessels (Wursig et al., 1998). Available
information suggests that beaked whales likely have enhanced
sensitivity to sonar sound, given documented incidents of stranding in
conjunction with specific circumstances of MFAS use, although few
definitive causal relationships between MFAS use and strandings have
been documented (see Potential Effects of Specified Activities on
Marine Mammals and their Habitat section). NMFS neither anticipates nor
proposes to authorize the mortality of beaked whales (or any other
species or stocks) resulting from exposure to active sonar.
Research and observations show that if beaked whales are exposed to
sonar or other active acoustic sources, they may startle, break off
feeding dives, and avoid the area of the sound source to levels of 157
dB re: 1 [micro]Pa, or below (McCarthy et al., 2011). For example,
after being exposed to 1-2 kHz upsweep naval sonar signals at a
received SPL of 107 dB re 1 [mu]Pa, Northern bottlenose whales began
moving in an unusually straight course, made a near 180[deg] turn away
from the source, and performed the longest and deepest dive (94 min,
2339 m) recorded for this species (Miller et al., 2015). Wensveen et
al. (2019) also documented avoidance behaviors in Northern bottlenose
whales exposed to 1-2 kHz tonal sonar signals with SPLs ranging between
117-126 dB re: 1 [micro]Pa, including interrupted diving behaviors,
elevated swim speeds, directed movements away from the sound source,
and cessation of acoustic signals throughout exposure periods. Acoustic
monitoring during actual sonar exercises revealed some beaked whales
continuing to forage at levels up to 157
[[Page 49751]]
dB re: 1 [micro]Pa (Tyack et al., 2011). Stimpert et al. (2014) tagged
a Baird's beaked whale, which was subsequently exposed to simulated
MFAS. Changes in the animal's dive behavior and locomotion were
observed when received level reached 127 dB re: 1 [mu]Pa. However,
Manzano-Roth et al. (2013) found that for beaked whale dives that
continued to occur during MFAS activity, differences from normal dive
profiles and click rates were not detected with estimated received
levels up to 137 dB re: 1 [micro]Pa while the animals were at depth
during their dives. In research done at the Navy's fixed tracking range
in the Bahamas, animals were observed to leave the immediate area of
the anti-submarine warfare training exercise (avoiding the sonar
acoustic footprint at a distance where the received level was ``around
140 dB SPL,'' according to Tyack et al. (2011)), but return within a
few days after the event ended (Claridge and Durban, 2009; McCarthy et
al., 2011; Moretti et al., 2009, 2010; Tyack et al., 2010, 2011). Joyce
et al. (2019) found that Blainville's beaked whales moved up to 68 km
away from an Atlantic Undersea Test and Evaluation Center site and
reduced time spent on deep dives after the onset of mid-frequency
active sonar exposure; whales did not return to the site until 2-4 days
after the exercises ended. Changes in acoustic activity have also been
documented. For example, Blainville's beaked whales showed decreased
group vocal periods after biannual multi-day Navy training activities
(Henderson et al., 2016). Tyack et al. (2011) reported that, in
reaction to sonar playbacks, most beaked whales stopped echolocating,
made long slow ascent to the surface, and moved away from the sound. A
similar behavioral response study conducted in Southern California
waters during the 2010-2011 field season found that Cuvier's beaked
whales exposed to MFAS displayed behavior ranging from initial
orientation changes to avoidance responses characterized by energetic
fluking and swimming away from the source (DeRuiter et al., 2013b).
However, the authors did not detect similar responses to incidental
exposure to distant naval sonar exercises at comparable received
levels, indicating that context of the exposures (e.g., source
proximity, controlled source ramp-up) may have been a significant
factor. The study itself found the results inconclusive and meriting
further investigation. Falcone et al. (2017) however, documented that
Cuvier's beaked whales had longer dives and surface durations after
exposure to mid-frequency active sonar, with the longer surface
intervals contributing to a longer interval between deep dives, a proxy
for foraging disruption in this species. Cuvier's beaked whale
responses suggested particular sensitivity to sound exposure consistent
with results for Blainville's beaked whale.
Populations of beaked whales and other odontocetes on the Bahamas
and other Navy fixed ranges that have been operating for decades appear
to be stable. Behavioral reactions (avoidance of the area of Navy
activity) seem most likely in cases where beaked whales are exposed to
anti-submarine sonar within a few tens of kilometers, especially for
prolonged periods (a few hours or more) since this is one of the most
sensitive marine mammal groups to anthropogenic sound of any species or
group studied to date and research indicates beaked whales will leave
an area where anthropogenic sound is present (De Ruiter et al., 2013;
Manzano-Roth et al., 2013; Moretti et al., 2014; Tyack et al., 2011).
Research involving tagged Cuvier's beaked whales in the SOCAL Range
Complex reported on by Falcone and Schorr (2012, 2014) indicates year-
round prolonged use of the Navy's training and testing area by these
beaked whales and has documented movements in excess of hundreds of
kilometers by some of those animals. Given that some of these animals
may routinely move hundreds of kilometers as part of their normal
pattern, leaving an area where sonar or other anthropogenic sound is
present may have little, if any, cost to such an animal. Photo
identification studies in the SOCAL Range Complex, a Navy range that is
utilized for training and testing, have identified approximately 100
Cuvier's beaked whale individuals with 40 percent having been seen in
one or more prior years, with re-sightings up to 7 years apart (Falcone
and Schorr, 2014). These results indicate long-term residency by
individuals in an intensively used Navy training and testing area,
which may also suggest a lack of long-term consequences as a result of
exposure to Navy training and testing activities. More than 8 years of
passive acoustic monitoring on the Navy's instrumented range west of
San Clemente Island documented no significant changes in annual and
monthly beaked whale echolocation clicks, with the exception of
repeated fall declines likely driven by natural beaked whale life
history functions (DiMarzio et al., 2018). Finally, results from
passive acoustic monitoring estimated that regional Cuvier's beaked
whale densities were higher than indicated by NMFS' broad scale visual
surveys for the United States West Coast (Hildebrand and McDonald,
2009).
Below we compile and summarize the information that supports our
preliminary determinations that the Navy's activities would not
adversely affect any of the beaked whale stocks through effects on
annual rates of recruitment or survival. Baird's, Cuvier's, and
Stejneger's beaked whales (Alaska stocks)
Baird's beaked whale, Cuvier's beaked whale, and Stejneger's beaked
whale are not listed as endangered or threatened species under the ESA,
and the 2019 Alaska SARs indicate that trend information is not
available for any of the Alaska stocks. No BIAs for beaked whales have
been identified in the GOA Study Area.
As indicated in Table 43, no abundance estimates are available for
any of the stocks. However, the ranges of all three stocks are large
compared to the GOA Study Area (Cuvier's is the smallest, occupying all
of the Gulf of Alaska, south of the Canadian border and west along the
Aleutian Islands. Baird's range even farther south and Baird's and
Stejneger's also cross north over the Aleutian Islands).
Regarding abundance and distribution of these species in the
vicinity of the TMAA, passive acoustic data indicate spatial overlap of
all three beaked whales; however, detections are spatially offset,
suggesting some level of habitat portioning in the Gulf of Alaska (Rice
et al., 2021). Peaks in detections by Rice et al. (2021) were also
temporally offset, with detections of Baird's beaked whale clicks
peaking in winter at the slope and in spring at the seamounts. Rice et
al. (2021) indicates Baird's beaked whales were highest in number at
Quinn seamount, which overlaps with the southern edge of the TMAA, and
therefore, a portion of this habitat is outside of the TMAA. Baumann
Pickering et al. (2012b) did not acoustically detect Baird's beaked
whales from July-October in the northern Gulf of Alaska (overlapping
with the majority of the Navy's potential training period), while
acoustic detections from November-January suggest that Baird's beaked
whales may winter in this area. Rice et al. (2021) reported the highest
detections of Baird's beaked whales within the TMAA during the spring
in the portion of the TMAA that is farther offshore, with lowest
detections in the summer and an increase in detections on the
continental slope in the winter, indicating that the whales are either
not producing clicks in the summer or they
[[Page 49752]]
are migrating farther north or south to feed or mate during this time.
Data from a satellite-tagged Baird's beaked whale off Southern
California recently documented movement north along the shelf-edge for
more than 400 nmi over a six-and-a-half-day period (Schorr et. al.,
Unpublished). If that example is reflective of more general behavior,
Baird's beaked whales present in the TMAA may have much larger home
ranges than the waters bounded by the TMAA, reducing the potential for
repeated takes of individuals.
Regarding Stejneger's beaked whale, passive acoustic monitoring
detected the whales most commonly at the slope and offshore in the TMAA
(Rice et al., 2021; Rice et al., 2018b; Rice et al., 2020b). At the
slope, Stejneger's beaked whale detections peaked in fall (Rice et al.,
2021). Rice et al. (2021) notes that to date, there have been no
documented sightings of Stejneger's beaked whales that were
simultaneous with recording of vocalizations, which is necessary to
confirm the vocalizations were produced by the species, and therefore,
detections should be interpreted with caution. Baumann-Pickering et al.
(2012b) recorded acoustic signals believed to be produced by
Stejneger's beaked whales (based on frequency characteristics,
interpulse interval, and geographic location; Baumann-Pickering et al.,
2012a) almost weekly from July 2011 to February 2012 in the northern
Gulf of Alaska.
Regarding Cuvier's beaked whale, passive acoustic monitoring at
five sites in the TMAA (Rice et al., 2021; Rice et al., 2015; Rice et
al., 2018b; Rice et al., 2020a) has intermittently detected Cuvier's
beaked whale vocalizations in low numbers in every month except April,
although there are generally multiple months in any given year where no
detections are made.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), the anticipated takes would occur within a
small portion of the stocks' ranges (including that none of the stocks
are expected to occur in the far western edge of the TMAA; U.S.
Department of the Navy, 2021) and would occur within the 21-day window
of the annual activities. In consideration of these factors and the
passive acoustic monitoring data described in this section, which
indicates relatively low beaked whale presence in the TMAA during the
Navy's potential training period, it is likely that a portion of the
stocks would be taken, and a subset of them may be taken on a few days,
with no indication that these days would be sequential.
Regarding the severity of those individual takes by Level B
harassment by behavioral disturbance, we have explained that the
duration of any exposure is expected to be between minutes and hours
(i.e., relatively short) and the received sound levels largely below
166 dB, though with beaked whales, which are considered somewhat more
sensitive, this could mean that some individuals would leave preferred
habitat for a day (i.e., moderate level takes). However, while
interrupted feeding bouts are a known response and concern for
odontocetes, we also know that there are often viable alternative
habitat options nearby. Regarding the severity of TTS takes
(anticipated for Cuvier's and Stejneger's beaked whales only), they are
expected to be low-level, of short duration, and mostly not in a
frequency band that would be expected to interfere with beaked whale
communication or other important low-frequency cues. Therefore, the
associated lost opportunities and capabilities are not at a level that
would impact reproduction or survival. As mentioned earlier in the
odontocete overview, we anticipate more severe effects from takes when
animals are exposed to higher received levels or sequential days of
impacts.
Altogether, none of these species are ESA-listed, only a portion of
the stocks are anticipated to be impacted, and any individual beaked
whale is likely to be disturbed at a moderate or sometimes low level.
This low magnitude and moderate to lower severity of harassment effects
is not expected to result in impacts on individual reproduction or
survival, let alone have impacts on annual rates of recruitment or
survival of this stock. No mortality, serious injury, or Level A
harassment is anticipated or proposed for authorization. For these
reasons, we have preliminarily determined, in consideration of all of
the effects of the Navy's activities combined, that the proposed
authorized take would have a negligible impact on the Alaska stocks of
beaked whales.
Dolphins and Small Whales
This section builds on the broader odontocete discussion above and
brings together the discussion of the different types and amounts of
take that different dolphin and small whale species and stocks would
likely incur, the applicable mitigation, and the status of the species
and stocks to support the preliminary negligible impact determinations
for each species or stock. For all dolphin and small whale stocks
discussed here, no mortality or Level A harassment is anticipated or
proposed for authorization.
In Table 44 below for dolphins and small whales, we indicate the
total annual numbers of take by Level A harassment and Level B
harassment, and a number indicating the instances of total take as a
percentage of abundance.
Table 44--Annual Estimated Takes by Level B Harassment and Level A Harassment for Dolphins and Small Whales in the TMAA and Number Indicating the
Instances of Total Take as a Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Instances of indicated types of incidental
take \1\
------------------------------------------------ Instances of
Level B harassment Level A Abundance total take as
Species Stock -------------------------------- harassment Total takes (NMFS SARs) percentage of
TTS (may also ---------------- \2\ abundance
Behavioral include
disturbance disturbance) PTS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Killer whale...................... Eastern North 64 17 0 81 300 27.0
Pacific Offshore.
Eastern North 119 24 0 143 587 24.4
Pacific Gulf of
Alaska, Aleutian
Islands, and Bering
Sea Transient.
Pacific white-sided dolphins...... North Pacific....... 1,102 472 0 1,574 26,880 5.9
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate
individuals, especially for disturbance.
\2\ Presented in the 2021 draft SARs or most recent SAR.
[[Page 49753]]
As described above, the large majority of Level B harassment by
behavioral disturbance to odontocetes, and thereby dolphins and small
whales, from hull-mounted sonar (MFAS) in the TMAA would result from
received levels between 160 and 172 dB SPL. Therefore, the majority of
takes by Level B harassment are expected to be in the form of low to
occasionally moderate responses of a generally shorter duration. As
mentioned earlier in this section, we anticipate more severe effects
from takes when animals are exposed to higher received levels or for
longer durations. Occasional milder occurrences of Level B harassment
by behavioral disturbance are unlikely to cause long-term consequences
for individual animals, much less have any effect on annual rates of
recruitment or survival. No mortality, serious injury, or Level A
harassment is expected or proposed for authorization.
Research and observations show that if delphinids are exposed to
sonar or other active acoustic sources they may react in a number of
ways depending on their experience with the sound source and what
activity they are engaged in at the time of the acoustic exposure.
Delphinids may not react at all until the sound source is approaching
within a few hundred meters to within a few kilometers depending on the
environmental conditions and species. Some dolphin species (the more
surface-dwelling taxa--typically those with ``dolphin'' in the common
name, such as bottlenose dolphins, spotted dolphins, spinner dolphins,
rough-toothed dolphins, etc., but not Risso's dolphin), especially
those residing in more industrialized or busy areas, have demonstrated
more tolerance for disturbance and loud sounds and many of these
species are known to approach vessels to bow-ride. These species are
often considered generally less sensitive to disturbance. Dolphins and
small whales that reside in deeper waters and generally have fewer
interactions with human activities are more likely to demonstrate more
typical avoidance reactions and foraging interruptions as described
above in the odontocete overview.
Below we compile and summarize the information that supports our
preliminary determinations that the Navy's activities would not
adversely affect any of the dolphins and small whales through effects
on annual rates of recruitment or survival.
Killer Whales (Eastern North Pacific Offshore; Eastern North Pacific
Gulf of Alaska, Aleutian Islands, and Bering Sea Transient)
No killer whale stocks in the TMAA are listed as DPSs under the
ESA, and no BIAs for killer whales have been identified in the GOA
Study Area. The Eastern North Pacific Offshore stock is reported as
``stable,'' and the population trend of the Eastern North Pacific Gulf
of Alaska, Aleutian Islands, and Bering Sea Transient stock is unknown.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), the number of estimated total instances of
take compared to the abundance is 27 percent for the Eastern North
Pacific Offshore stock and 24 percent for the Eastern North Pacific
Gulf of Alaska, Aleutian Islands, and Bering Sea Transient stock. This
information indicates that only a portion of each stock is likely
impacted, with those individuals disturbed on likely one, but not more
than a few non-sequential days within the 21 days per year. Regarding
the severity of those individual takes by Level B harassment by
behavioral disturbance, we have explained that the duration of any
exposure is expected to be between minutes and hours (i.e., relatively
short) and the received sound levels largely below 172 dB (i.e., of a
lower, to occasionally moderate, level and less likely to evoke a
severe response). Regarding the severity of TTS takes, they are
expected to be low-level, of short duration, and mostly not in a
frequency band that would be expected to interfere with killer whale
communication or other important low-frequency cues. Therefore, the
associated lost opportunities and capabilities are not at a level that
would impact reproduction or survival.
Altogether, these killer whale stocks are not listed under the ESA.
The Eastern North Pacific Offshore stock is reported as ``stable,'' and
the population trend of the Eastern North Pacific Gulf of Alaska,
Aleutian Islands, and Bering Sea Transient stock is unknown. Only a
portion of these killer whale stocks is anticipated to be impacted, and
any individual is likely to be disturbed at a low-moderate level, with
the taken individuals likely exposed on one day but not more than a few
non-sequential days within a year. This low magnitude and severity of
harassment effects is unlikely to result in impacts on individual
reproduction or survival, let alone have impacts on annual rates of
recruitment or survival of either of the stocks. No mortality or Level
A harassment is anticipated or proposed for authorization for either of
the stocks. For these reasons, we have preliminarily determined, in
consideration of all of the effects of the Navy's activities combined,
that the proposed authorized take would have a negligible impact on
these killer whale stocks.
Pacific White-Sided Dolphins (North Pacific Stock)
Pacific white-sided dolphins are not listed under the ESA and the
current population trend of the North Pacific stock is unknown. No BIAs
for this stock have been identified in the GOA Study Area.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), the number of estimated total instances of
take compared to the abundance is 6 percent. Given the number of takes,
only a small portion of the stock is likely impacted, and individuals
are likely disturbed between one and a few days, most likely non-
sequential, within a year. Regarding the severity of those individual
takes by Level B harassment by behavioral disturbance, we have
explained that the duration of any exposure is expected to be between
minutes and hours (i.e., relatively short) and the received sound
levels largely below 172 dB (i.e., of a lower, to occasionally
moderate, level and less likely to evoke a severe response). However,
while interrupted feeding bouts are a known response and concern for
odontocetes, we also know that there are often viable alternative
habitat options nearby. Regarding the severity of TTS takes, they are
expected to be low-level, of short duration, and mostly not in a
frequency band that would be expected to interfere with dolphin
communication or other important low-frequency cues. Therefore, the
associated lost opportunities and capabilities are not at a level that
would impact reproduction or survival.
Altogether, though the status of this stock is unknown, this stock
is not listed under the ESA. Any individual is likely to be disturbed
at a low-moderate level, and those individuals likely disturbed on one
to a few non-sequential days within a year. This low magnitude and
severity of harassment effects is not expected to result in impacts on
individual reproduction or survival, let alone have impacts on annual
rates of recruitment or survival of this stock. No mortality, serious
injury, or Level A harassment is anticipated or proposed for
authorization. For these reasons, we have preliminarily determined, in
consideration of all of the effects of the Navy's activities combined,
that the
[[Page 49754]]
proposed authorized take would have a negligible impact on the North
Pacific stock of Pacific white-sided dolphins.
Dall's Porpoise (Alaska Stock)
This section builds on the broader odontocete discussion above and
brings together the discussion of the different types and amounts of
take that this porpoise stock would likely incur, the applicable
mitigation, and the status of the stock to support the negligible
impact determination.
In Table 45 below for Dall's porpoise, we indicate the total annual
numbers of take by Level A harassment and Level B harassment, and a
number indicating the instances of total take as a percentage of
abundance.
Table 45--Annual Estimated Takes by Level B Harassment and Level A Harassment for Dall's Porpoise in the TMAA and Number Indicating the Instances of
Total Take as a Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Instances of indicated types of incidental take
\1\
--------------------------------------------------- Instances of
Level B harassment Level A Abundance (NMFS total take as
Species Stock ---------------------------------- harassment Total takes SARs) \2\ percentage of
TTS (may also ----------------- abundance
Behavioral include
disturbance disturbance) PTS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dall's porpoise................ Alaska........... 348 8,939 64 9,351 83,400 11.2
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the Specified Activity. Not all takes represent separate
individuals, especially for disturbance.
\2\ Presented in the 2021 draft SARs or most recent SAR.
Dall's porpoise is not listed under the ESA and the current
population trend for the Alaska stock is unknown. No BIAs for Dall's
porpoise have been identified in the GOA Study Area.
While harbor porpoises have been observed to be especially
sensitive to human activity, the same types of responses have not been
observed in Dall's porpoises. Dall's porpoises are typically notably
longer than, and weigh more than twice as much as, harbor porpoises,
making them generally less likely to be preyed upon and likely
differentiating their behavioral repertoire somewhat from harbor
porpoises. Further, they are typically seen in large groups and feeding
aggregations, or exhibiting bow-riding behaviors, which is very
different from the group dynamics observed in the more typically
solitary, cryptic harbor porpoises, which are not often seen bow-
riding. For these reasons, Dall's porpoises are not treated as an
especially sensitive species (versus harbor porpoises which have a
lower behavioral harassment threshold and more distant cutoff) but,
rather, are analyzed similarly to other odontocetes (with takes from
the sonar bin in the TMAA resulting from the same received levels
reported in the Odontocete section above). Therefore, the majority of
Level B harassment by behavioral disturbance is expected to be in the
form of milder responses compared to higher level exposures. As
mentioned earlier in this section, we anticipate more severe effects
from takes when animals are exposed to higher received levels.
We note that Dall's porpoise, as a HF-sensitive species, has a
lower PTS threshold than other groups and therefore is generally more
likely to experience TTS and PTS, and potentially occasionally to a
greater degree, and NMFS accordingly has evaluated and authorized
higher numbers. Also, however, regarding PTS from sonar exposure,
porpoises are still likely to avoid sound levels that would cause
higher levels of TTS (greater than 20 dB) or PTS. Therefore, even
though the number of TTS takes are higher than for other odontocetes,
any PTS is expected to be at a lower to occasionally moderate level and
for all of the reasons described above, TTS and PTS takes are not
expected to impact reproduction or survival of any individual.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance), the number of estimated total instances of
take compared to the abundance is 11 percent. This indicates that only
a small portion of this stock is likely to be impacted, and a subset of
those individuals would likely be taken on no more than a few non-
sequential days within a year. Regarding the severity of those
individual takes by Level B harassment by behavioral disturbance, we
have explained that the duration of any exposure is expected to be
between minutes and hours (i.e., relatively short) and the received
sound levels largely below 172 dB (i.e., of a lower, to occasionally
moderate, level and less likely to evoke a severe response). Regarding
the severity of TTS takes, they are expected to be low-level, of short
duration, and mostly not in a frequency band that would be expected to
interfere with communication or other important low-frequency cues.
Therefore, the associated lost opportunities and capabilities are not
at a level that would impact reproduction or survival.
For the same reasons explained above for TTS (low to occasionally
moderate level and the likely frequency band), while a small permanent
loss of hearing sensitivity may include some degree of energetic costs
for compensating or may mean some small loss of opportunities or
detection capabilities, the estimated annual takes by Level A
harassment by PTS for this stock (64 takes) would be unlikely to impact
behaviors, opportunities, or detection capabilities to a degree that
would interfere with reproductive success or survival of any
individuals.
Altogether, the status of the Alaska stock of Dall's porpoise is
unknown, however Dall's porpoise are not listed as endangered or
threatened under the ESA. Only a small portion of this stock is likely
to be impacted, any individual is likely to be disturbed at a low-
moderate level, and a subset of taken individuals would likely be taken
on a few non-sequential days within a year. This low magnitude and
severity of Level B harassment effects is not expected to result in
impacts on individual reproduction or survival, much less annual rates
of recruitment or survival. Some individuals (64 annually) could be
taken by PTS of likely low to occasionally moderate severity. A small
permanent loss of hearing sensitivity (PTS) may include some degree of
energetic costs for compensating or may mean some small loss of
opportunities or detection capabilities, but at the expected scale the
estimated takes by Level A harassment by PTS for this stock would be
unlikely, alone or in combination with the Level B harassment take by
behavioral disturbance and TTS, to impact behaviors, opportunities, or
detection capabilities to a degree that
[[Page 49755]]
would interfere with reproductive success or survival of any
individuals, let alone have impacts on annual rates of recruitment or
survival of this stock. No mortality or serious injury and no Level A
harassment from non-auditory tissue damage is anticipated or proposed
for authorization. For these reasons, we have preliminarily determined,
in consideration of all of the effects of the Navy's activities
combined, that the proposed authorized take would have a negligible
impact on the Alaska stock of Dall's porpoise.
Pinnipeds
This section builds on the broader discussion above and brings
together the discussion of the different types and amounts of take that
different species and stocks would likely incur, the applicable
mitigation, and the status of the species and stocks to support the
negligible impact determinations for each species or stock. We have
described (earlier in this section) the unlikelihood of any masking
having effects that would impact the reproduction or survival of any of
the individual marine mammals affected by the Navy's activities. We
have also described above in the Potential Effects of Specified
Activities on Marine Mammals and their Habitat section the unlikelihood
of any habitat impacts having effects that would impact the
reproduction or survival of any of the individual marine mammals
affected by the Navy's activities. For pinnipeds, there is no mortality
or serious injury and no Level A harassment from non-auditory tissue
damage from sonar or explosives anticipated or proposed to be
authorized for any species.
Regarding behavioral disturbance, research and observations show
that pinnipeds in the water may be tolerant of anthropogenic noise and
activity (a review of behavioral reactions by pinnipeds to impulsive
and non-impulsive noise can be found in Richardson et al. (1995) and
Southall et al. (2007)). Available data, though limited, suggest that
exposures between approximately 90 and 140 dB SPL do not appear to
induce strong behavioral responses in pinnipeds exposed to non-pulse
sounds in water (Costa et al., 2003; Jacobs and Terhune, 2002;
Kastelein et al., 2006c). Based on the limited data on pinnipeds in the
water exposed to multiple pulses (small explosives, impact pile
driving, and seismic sources), exposures in the approximately 150 to
180 dB SPL range generally have limited potential to induce avoidance
behavior in pinnipeds (Blackwell et al., 2004; Harris et al., 2001;
Miller et al., 2004). If pinnipeds are exposed to sonar or other active
acoustic sources they may react in a number of ways depending on their
experience with the sound source and what activity they are engaged in
at the time of the acoustic exposure. Pinnipeds may not react at all
until the sound source is approaching within a few hundred meters and
then may alert, ignore the stimulus, change their behaviors, or avoid
the immediate area by swimming away or diving. Effects on pinnipeds
that are taken by Level B harassment in the TMAA, on the basis of
reports in the literature as well as Navy monitoring from past
activities, would likely be limited to reactions such as increased
swimming speeds, increased surfacing time, or decreased foraging (if
such activity were occurring). Most likely, individuals would simply
move away from the sound source and be temporarily displaced from those
areas, or not respond at all, which would have no effect on
reproduction or survival. While some animals may not return to an area,
or may begin using an area differently due to training activities, most
animals are expected to return to their usual locations and behavior.
Given their documented tolerance of anthropogenic sound (Richardson et
al., 1995 and Southall et al., 2007), repeated exposures of individuals
of any of these species to levels of sound that may cause Level B
harassment are unlikely to result in hearing impairment or to
significantly disrupt foraging behavior. Thus, even repeated Level B
harassment of some small subset of individuals of an overall stock is
unlikely to result in any significant realized decrease in fitness to
those individuals that would result in any adverse impact on rates of
recruitment or survival for the stock as a whole.
While no take of Steller sea lion is anticipated or proposed to be
authorized, we note that the GOA Study Area boundary was intentionally
designed to avoid ESA-designated Steller sea lion critical habitat.
All the pinniped species discussed in this section would benefit
from the procedural mitigation measures described earlier in the
Proposed Mitigation Measures section.
In Table 46 below for pinnipeds, we indicate the total annual
numbers of take by Level A harassment and Level B harassment, and a
number indicating the instances of total take as a percentage of
abundance.
Table 46--Annual Estimated Takes by Level B Harassment and Level A Harassment for Pinnipeds in the TMAA and Number Indicating the Instances of Total
Take as a Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Instances of indicated types of incidental
take \1\
------------------------------------------------ Instances of
Level B harassment Level A Abundance total take as
Species Stock -------------------------------- harassment Total Takes (NMFS SARs) percentage of
TTS (may also ---------------- \2\ abundance
Behavioral include
disturbance disturbance) PTS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Northern fur seal................. Eastern Pacific..... 2,972 31 0 3,003 626,618 <1
Northern fur seal................. California.......... 60 1 0 61 14,050 <1
Northern elephant seal............ California.......... 904 1,643 8 2,555 187,386 1.3
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate
individuals, especially for disturbance.
\2\ Presented in the 2021 draft SARs or most recent SAR.
The majority of takes by harassment of pinnipeds in the TMAA are
caused by sources from the MFAS bin (which includes hull-mounted sonar)
because they are high level sources at a frequency (1-10 kHz) which
overlaps the most sensitive portion of the pinniped hearing range, and
of the sources expected to result in take, they are used in a large
portion of exercises (see Table 1 and Table 3). Most of the takes (>99
percent) from the MF1 bin in the TMAA would result from received levels
between 166 and 178 dB SPL. For the remaining active sonar bin types,
the percentages are as follows: MF4 = 97 percent between 148 and 172 dB
SPL and MF5 = 99 percent between 130 and
[[Page 49756]]
160 dB SPL. Given the levels they are exposed to and pinniped
sensitivity, most responses would be of a lower severity, with only
occasional responses likely to be considered moderate, but still of
generally short duration.
As mentioned earlier in this section, we anticipate more severe
effects from takes when animals are exposed to higher received levels.
Occasional milder takes by Level B harassment by behavioral disturbance
are unlikely to cause long-term consequences for individual animals or
populations, especially when they are not expected to be repeated over
sequential multiple days. For all pinnipeds except Northern elephant
seals, no take is expected to occur from explosives. For Northern
elephant seals, harassment takes from explosives (behavioral
disturbance, TTS, and PTS) comprise a very small fraction of those
caused by exposure to active sonar.
Because the majority of harassment takes of pinnipeds result from
narrowband sources in the range of 1-10 kHz, the vast majority of
threshold shift caused by Navy sonar sources would typically occur in
the range of 2-20 kHz. This frequency range falls within the range of
pinniped hearing, however, pinniped vocalizations typically span a
somewhat lower range than this (<0.2 to 10 kHz) and threshold shift
from active sonar would often be in a narrower band (reflecting the
narrower band source that caused it), which means that TTS incurred by
pinnipeds would typically only interfere with communication within a
portion of a pinniped's range (if it occurred during a time when
communication with conspecifics was occurring). As discussed earlier,
it would only be expected to be of a short duration and relatively
small degree. Many of the other critical sounds that serve as cues for
navigation and prey (e.g., waves, fish, invertebrates) occur below a
few kHz, which means that detection of these signals would not be
inhibited by most threshold shifts either. The very low number of takes
by threshold shifts that might be incurred by individuals exposed to
explosives would likely be lower frequency (5 kHz or less) and spanning
a wider frequency range, which could slightly lower an individual's
sensitivity to navigational or prey cues, or a small portion of
communication calls, for several minutes to hours (if temporary) or
permanently.
Neither of these species are ESA-listed and the SAR indicates that
the status of the Eastern Pacific stock of Northern fur seal is stable,
the California stock of Northern fur seal is increasing, and the
California stock of Northern elephant seal is increasing. BIAs have not
been identified for pinnipeds.
Regarding the magnitude of takes by Level B harassment (TTS and
behavioral disturbance) for the Eastern Pacific and California stocks
of Northern fur seals, the estimated instances of takes as compared to
the stock abundance is <1 percent for each stock. For the California
stock of Northern elephant seal, the number of estimated total
instances of take compared to the abundance is 1 percent. This
information indicates that only a very small portion of individuals in
these stocks are likely impacted, particularly given the large ranges
of the stocks. Impacted individuals would be disturbed on likely one,
but not more than a few non-sequential days within a year.
Regarding the severity of those individual takes by Level B
harassment by behavioral disturbance for all pinniped stocks, we have
explained that the duration of any exposure is expected to be between
minutes and hours (i.e., relatively short) and the received sound
levels largely below 178 dB, which is considered a relatively low to
occasionally moderate level for pinnipeds.
Regarding the severity of TTS takes, they are expected to be low-
level, of short duration, and mostly not in a frequency band that would
be expected to interfere with pinniped communication or other important
low-frequency cues. Therefore, the associated lost opportunities and
capabilities are not at a level that would impact reproduction or
survival. For these same reasons (low level and frequency band), while
a small permanent loss of hearing sensitivity may include some degree
of energetic costs for compensating or may mean some small loss of
opportunities or detection capabilities, the 8 estimated Level A
harassment takes by PTS for the California stock of Northern elephant
seal would be unlikely to impact behaviors, opportunities, or detection
capabilities to a degree that would interfere with reproductive success
or survival of any individuals.
Altogether, none of these species are listed under the ESA, and the
SARs indicate that the status of the Eastern Pacific stock of Northern
fur seal is stable, the California stock of Northern fur seal is
increasing, and the California stock of Northern elephant seal is
increasing. No mortality or serious injury and no Level A harassment
from non-auditory tissue damage for pinnipeds is anticipated or
proposed for authorization. Level A harassment by PTS is only
anticipated for the California stock of Northern elephant seal (8 takes
by Level A harassment). For all three pinniped stocks, only a small
portion of the stocks are anticipated to be impacted and any individual
is likely to be disturbed at a low-moderate level. This low magnitude
and severity of harassment effects is not expected to result in impacts
on individual reproduction or survival, let alone have impacts on
annual rates of recruitment or survival of these stocks. For these
reasons, in consideration of all of the effects of the Navy's
activities combined, we have preliminarily determined that the proposed
authorized take would have a negligible impact on all three stocks of
pinnipeds.
Preliminary Determination
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the specified activities will have a negligible impact
on all affected marine mammal species or stocks.
Subsistence Harvest of Marine Mammals
In order to issue an incidental take authorization, NMFS must find
that the specified activity will not have an ``unmitigable adverse
impact'' on the subsistence uses of the affected marine mammal species
or stocks by Alaska Natives. NMFS has defined ``unmitigable adverse
impact'' in 50 CFR 216.103 as an impact resulting from the specified
activity: (1) That is likely to reduce the availability of the species
to a level insufficient for a harvest to meet subsistence needs by: (i)
Causing the marine mammals to abandon or avoid hunting areas; (ii)
Directly displacing subsistence users; or (iii) Placing physical
barriers between the marine mammals and the subsistence hunters; and
(2) That cannot be sufficiently mitigated by other measures to increase
the availability of marine mammals to allow subsistence needs to be
met.
When applicable, NMFS must prescribe means of effecting the least
practicable adverse impact on the availability of the species or stocks
for subsistence uses. As discussed in the Proposed Mitigation Measures
section, evaluation of potential mitigation measures includes
consideration of two primary factors: (1) The manner in which, and the
degree to which, implementation of the potential measure(s) is expected
to reduce
[[Page 49757]]
adverse impacts on the availability of species or stocks for
subsistence uses, and (2) the practicability of the measure(s) for
applicant implementation.
The Navy has met with and will continue to engage in meaningful
consultation and communication with several federally recognized Alaska
Native tribes that have traditional marine mammal harvest areas in the
GOA (though, as noted below, these areas do not overlap directly with
the GOA Study Area). Further, the Navy will continue to keep the Tribes
informed of the timeframes of future joint training exercises.
To our knowledge, subsistence hunting of marine mammals does not
occur in the GOA Study Area where training activities would occur. The
GOA Study Area is located over 12 nmi from shore with the nearest
inhabited land being the Kenai Peninsula (24 nmi from the GOA Study
Area). Information provided by Tribes in previous conversations with
the Navy, and according to Alaska Department of Fish and Game (1995),
indicates that harvest of pinnipeds occurs nearshore, and the Tribes do
not use the GOA Study Area for subsistence hunting of marine mammals.
The TMAA portion of the GOA Study Area is the closest to the area of
nearshore subsistence harvest conducted by the Sun'aq Tribe of Kodiak,
the Native Village of Eyak, and the Yakutat Tlingit Tribe (Alaska
Department of Fish and Game, 1995). The WMA is offshore of subsistence
harvest areas that occur in Unalaska, Akutan, False Pass, Sand Point,
and King Cove (Alaska Department of Fish and Game, 1997). The Tribes
listed here harvest harbor seals and sea lions (Alaska Department of
Fish and Game, 1995, 1997).
In addition to the distance between subsistence hunting areas and
the GOA Study Area, which would ensure that the Navy's activities do
not displace subsistence users or place physical barriers between the
marine mammals and the subsistence hunters, there is no reason to
believe that any behavioral disturbance or limited TTS or PTS of
pinnipeds that occurs offshore in the GOA Study Area would affect their
subsequent behavior in a manner that would interfere with subsistence
uses should those pinnipeds later interact with hunters, particularly
given that neither harbor seals, Steller sea lions, or California sea
lions are expected to be taken by the Navy's training activities. The
specified activity would be a continuation of the types of training
activities that have been ongoing for more than a decade, and as
discussed in the 2011 GOA FEIS/OEIS and 2016 GOA FSEIS/OEIS, no impacts
on traditional subsistence practices or resources are predicted to
result from the specified activity.
Based on the information above, NMFS has preliminarily determined
that the total taking of affected species or stocks would not have an
unmitigable adverse impact on the availability of the species or stocks
for taking for subsistence purposes. However, we have limited
information on marine mammal subsistence use in the GOA Study Area and
seek additional information pertinent to making the final
determination.
Classification
Endangered Species Act
There are eight marine mammal species under NMFS jurisdiction that
are listed as endangered or threatened under the ESA with confirmed or
possible occurrence in the GOA Study Area: North Pacific right whale,
humpback whale (Mexico, Western North Pacific, and Central America
DPSs), blue whale, fin whale, sei whale, gray whale (Western North
Pacific stock), sperm whale, and Steller sea lion (Western DPS). The
humpback whale has critical habitat recently designated under the ESA
in the TMAA portion of the GOA Study Area (86 FR 21082; April 21,
2021). As discussed previously, the GOA Study Area boundaries were
intentionally designed to avoid ESA-designated critical habitat for
Steller sea lions.
The Navy will consult with NMFS pursuant to section 7 of the ESA
for GOA Study Area activities. NMFS will also consult internally on the
issuance of the regulations and an LOA under section 101(a)(5)(A) of
the MMPA.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must evaluate our proposed actions and alternatives with respect
to potential impacts on the human environment. Accordingly, NMFS plans
to adopt the GOA SEIS/OEIS for the GOA Study Area provided our
independent evaluation of the document finds that it includes adequate
information analyzing the effects on the human environment of issuing
regulations and an LOA under the MMPA. NMFS is a cooperating agency on
the 2020 GOA DSEIS/OEIS and 2022 Supplement to the 2020 GOA DSEIS/OEIS
and has worked extensively with the Navy in developing the documents.
The 2020 GOA DSEIS/OEIS and 2022 Supplement to the 2020 GOA DSEIS/OEIS
were made available for public comment in February 2020 and March 2022,
respectively, at https://www.goaeis.com/, which also provides
additional information about the NEPA process. We will review all
comments prior to concluding our NEPA process and making a final
decision on the MMPA rulemaking and request for a LOA.
Regulatory Flexibility Act
The Office of Management and Budget has determined that this
proposed rule is not significant for purposes of Executive Order 12866.
Pursuant to the Regulatory Flexibility Act (RFA), the Chief Counsel
for Regulation of the Department of Commerce has certified to the Chief
Counsel for Advocacy of the Small Business Administration that this
proposed rule, if adopted, would not have a significant economic impact
on a substantial number of small entities. The RFA requires Federal
agencies to prepare an analysis of a rule's impact on small entities
whenever the agency is required to publish a notice of proposed
rulemaking. However, a Federal agency may certify, pursuant to 5 U.S.C.
605(b), that the action will not have a significant economic impact on
a substantial number of small entities. The Navy is the sole entity
that would be affected by this rulemaking, and the Navy is not a small
governmental jurisdiction, small organization, or small business, as
defined by the RFA. Any requirements imposed by an LOA issued pursuant
to these regulations, and any monitoring or reporting requirements
imposed by these regulations, would be applicable only to the Navy.
NMFS does not expect the issuance of these regulations or the
associated LOA to result in any impacts to small entities pursuant to
the RFA. Because this action, if adopted, would directly affect the
Navy and not a small entity, NMFS concludes that the action would not
result in a significant economic impact on a substantial number of
small entities.
List of Subjects in 50 CFR Part 218
Exports, Fish, Imports, Incidental take, Indians, Labeling, Marine
mammals, Navy, Penalties, Reporting and recordkeeping requirements,
Seafood, Sonar, Transportation.
[[Page 49758]]
Dated: July 28, 2022.
Samuel D. Rauch, III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.
For reasons set forth in the preamble, 50 CFR part 218 is proposed
to be amended as follows:
PART 218--REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE
MAMMALS
0
1. The authority citation for part 218 continues to read as follows:
Authority: 16 U.S.C. 1361 et seq., unless otherwise noted.
0
2. Revise subpart P to read as follows:
Subpart P--Taking and Importing Marine Mammals; U.S. Navy Training
Activities in the Gulf of Alaska Study Area
Sec.
218.150 Specified activity and geographical region.
218.151 Effective dates.
218.152 Permissible methods of taking.
218.153 Prohibitions.
218.154 Mitigation requirements.
218.155 Requirements for monitoring and reporting.
218.156 Letters of Authorization.
218.157 Renewals and modifications of Letter of Authorization.
218.158 [Reserved]
Sec. 218.150 Specified activity and geographical region.
(a) Regulations in this subpart apply only to the U.S. Navy (Navy)
for the taking of marine mammals that occurs in the area described in
paragraph (b) of this section and that occurs incidental to the
activities listed in paragraph (c) of this section.
(b) The GOA Study Area is entirely at sea and is comprised of three
areas: a Temporary Maritime Activities Area (TMAA) a warning area, and
the Western Maneuver Area (WMA) located south and west of the TMAA. The
TMAA and WMA are temporary areas established within the GOA for ships,
submarines, and aircraft to conduct training activities. The TMAA is a
polygon roughly resembling a rectangle oriented from northwest to
southeast, approximately 300 nautical miles (nmi; 556 km) in length by
150 nmi (278 km) in width, located south of Montague Island and east of
Kodiak Island. The warning area overlaps and extends slightly beyond
the northern corner of the TMAA. The WMA provides an additional 185,806
nmi\2\ of surface, sub-surface, and airspace training area to support
activities occurring within the TMAA. The boundary of the WMA follows
the bottom of the slope at the 4,000 m contour line.
(c) The taking of marine mammals by the Navy is only authorized if
it occurs incidental to the Navy conducting training activities,
including:
(1) Anti-submarine warfare; and
(2) Surface warfare.
Sec. 218.151 Effective dates.
Regulations in this subpart are effective from December 15, 2022
through December 14, 2029.
Sec. 218.152 Permissible methods of taking.
(a) Under a Letter of Authorization (LOA) issued pursuant to Sec.
216.106 of this chapter and Sec. 218.156, the Holder of the LOA
(hereinafter ``Navy'') may incidentally, but not intentionally, take
marine mammals within the TMAA only, as described in Sec. 218.150(b),
by Level A harassment and Level B harassment associated with the use of
active sonar and other acoustic sources and explosives, provided the
activity is in compliance with all terms, conditions, and requirements
of this subpart and the applicable LOA.
(b) The incidental take of marine mammals by the activities listed
in Sec. 218.150(c) is limited to the following species:
Table 1 to Sec. 218.152(b)
------------------------------------------------------------------------
Species Stock
------------------------------------------------------------------------
Blue whale................... Central North Pacific.
Blue whale................... Eastern North Pacific.
Fin whale.................... Northeast Pacific.
Humpback whale............... Western North Pacific.
Humpback whale............... Central North Pacific.
Humpback whale............... California/Oregon/Washington.
Minke whale.................. Alaska.
North Pacific right whale.... Eastern North Pacific.
Sei whale.................... Eastern North Pacific.
Gray whale................... Eastern North Pacific.
Killer whale................. Eastern North Pacific Offshore.
Killer whale................. Eastern North Pacific Gulf of Alaska,
Aleutian Islands, and Bering Sea
Transient.
Pacific white-sided dolphin.. North Pacific.
Dall's porpoise.............. Alaska.
Sperm whale.................. North Pacific.
Baird's beaked whale......... Alaska.
Cuvier's beaked whale........ Alaska.
Stejneger's beaked whale..... Alaska.
Northern fur seal............ Eastern Pacific.
Northern fur seal............ California.
Northern elephant seal....... California.
------------------------------------------------------------------------
Sec. 218.153 Prohibitions.
(a) Except for incidental takings contemplated in Sec. 218.152(a)
and authorized by an LOA issued under Sec. Sec. 216.106 of this
chapter and 218.156, it shall be unlawful for any person to do any of
the following in connection with the activities listed in Sec.
218.150(c):
(1) Violate, or fail to comply with, the terms, conditions, and
requirements of this subpart or an LOA issued under Sec. Sec. 216.106
of this chapter and 218.156;
(2) Take any marine mammal not specified in Sec. 218.152(b);
(3) Take any marine mammal specified in Sec. 218.152(b) in any
manner other than as specified in the LOA; or
(4) Take a marine mammal specified in Sec. 218.152(b) if NMFS
determines such taking results in more than a negligible impact on the
species or stocks of such marine mammal.
[[Page 49759]]
(b) [Reserved]
Sec. 218.154 Mitigation requirements.
(a) When conducting the activities identified in Sec. 218.150(c),
the mitigation measures contained in any LOA issued under Sec. Sec.
216.106 of this chapter and 218.156 must be implemented. These
mitigation measures include, but are not limited to:
(1) Procedural mitigation. Procedural mitigation is mitigation that
the Navy must implement whenever and wherever an applicable training
activity takes place within the GOA Study Area for acoustic stressors
(i.e., active sonar, weapons firing noise), explosive stressors (i.e.,
large-caliber projectiles, bombs), and physical disturbance and strike
stressors (i.e., vessel movement, towed in-water devices, small-,
medium-, and large-caliber non-explosive practice munitions, non-
explosive bombs).
(i) Environmental awareness and education. Appropriate Navy
personnel (including civilian personnel) involved in mitigation and
training activity reporting under the specified activities will
complete the environmental compliance training modules identified in
their career path training plan, as specified in the LOA.
(ii) Active sonar. Active sonar includes mid-frequency active
sonar, and high-frequency active sonar. For vessel-based active sonar
activities, mitigation applies only to sources that are positively
controlled and deployed from manned surface vessels (e.g., sonar
sources towed from manned surface platforms). For aircraft-based active
sonar activities, mitigation applies only to sources that are
positively controlled and deployed from manned aircraft that do not
operate at high altitudes (e.g., rotary-wing aircraft). Mitigation does
not apply to active sonar sources deployed from unmanned aircraft or
aircraft operating at high altitudes (e.g., maritime patrol aircraft).
(A) Number of Lookouts and observation platform for hull-mounted
sources. For hull-mounted sources, the Navy must have one Lookout for
platforms with space or manning restrictions while underway (at the
forward part of a small boat or ship) and platforms using active sonar
while moored or at anchor; and two Lookouts for platforms without space
or manning restrictions while underway (at the forward part of the
ship).
(B) Number of Lookouts and observation platform for sources not
hull-mounted. For sources that are not hull-mounted, the Navy must have
one Lookout on the ship or aircraft conducting the activity.
(C) Prior to activity. Prior to the initial start of the activity
(e.g., when maneuvering on station), Navy personnel must observe the
mitigation zone for floating vegetation and marine mammals; if floating
vegetation or a marine mammal is observed, Navy personnel must relocate
or delay the start of active sonar transmission until the mitigation
zone is clear of floating vegetation or until the conditions in
paragraph (a)(1)(ii)(F) of this section are met for marine mammals.
(D) During the activity for hull-mounted mid-frequency active
sonar. During the activity, for hull-mounted mid-frequency active
sonar, Navy personnel must observe the following mitigation zones for
marine mammals.
(1) Powerdowns for marine mammals. Navy personnel must power down
active sonar transmission by 6 dB if a marine mammal is observed within
1,000 yd (914.4 m) of the sonar source; Navy personnel must power down
active sonar transmission an additional 4 dB (10 dB total) if a marine
mammal is observed within 500 yd (457.2 m) of the sonar source.
(2) Shutdowns for marine mammals. Navy personnel must cease
transmission if a marine mammal is observed within 200 yd (182.9 m) of
the sonar source.
(E) During the activity, for mid-frequency active sonar sources
that are not hull-mounted, and high-frequency active sonar. During the
activity, for mid-frequency active sonar sources that are not hull-
mounted and high-frequency active sonar, Navy personnel must observe
the mitigation zone for marine mammals. Navy personnel must cease
transmission if a marine mammal is observed within 200 yd (182.9 m) of
the sonar source.
(F) Commencement/recommencement conditions after a marine mammal
sighting before or during the activity. Navy personnel must allow a
sighted marine mammal to leave the mitigation zone prior to the initial
start of the activity (by delaying the start) or during the activity
(by not recommencing or powering up active sonar transmission) until
one of the following conditions has been met:
(1) Observed exiting. The animal is observed exiting the mitigation
zone;
(2) Thought to have exited. The animal is thought to have exited
the mitigation zone based on a determination of its course, speed, and
movement relative to the sonar source;
(3) Clear from additional sightings. The mitigation zone has been
clear from any additional sightings for 10 minutes (min) for aircraft-
deployed sonar sources or 30 minutes for vessel-deployed sonar sources;
(4) Sonar source transit. For mobile activities, the active sonar
source has transited a distance equal to double that of the mitigation
zone size beyond the location of the last sighting; or
(5) Bow-riding dolphins. For activities using hull-mounted sonar,
the Lookout concludes that dolphins are deliberately closing in on the
ship to ride the ship's bow wave, and are therefore out of the main
transmission axis of the sonar (and there are no other marine mammal
sightings within the mitigation zone).
(iii) Weapons firing noise. Weapons firing noise associated with
large-caliber gunnery activities.
(A) Number of Lookouts and observation platform. One Lookout must
be positioned on the ship conducting the firing. Depending on the
activity, the Lookout could be the same as the one provided for under
``Explosive large-caliber projectiles'' or under ``Small-, medium-, and
large-caliber non-explosive practice munitions'' in paragraphs
(a)(1)(iv)(A) and (a)(1)(viii)(A) of this section.
(B) Mitigation zone. Thirty degrees on either side of the firing
line out to 70 yd (64 m) from the muzzle of the weapon being fired.
(C) Prior to activity. Prior to the initial start of the activity,
Navy personnel must observe the mitigation zone for floating vegetation
and marine mammals; if floating vegetation or a marine mammal is
observed, Navy personnel must relocate or delay the start of weapons
firing until the mitigation zone is clear of floating vegetation or
until the conditions in paragraph (a)(1)(iii)(E) of this section are
met for marine mammals.
(D) During activity. During the activity, Navy personnel must
observe the mitigation zone for marine mammals; if a marine mammal is
observed, Navy personnel must cease weapons firing.
(E) Commencement/recommencement conditions after a marine mammal
sighting before or during the activity. Navy personnel must allow a
sighted marine mammal to leave the mitigation zone prior to the initial
start of the activity (by delaying the start) or during the activity
(by not recommencing weapons firing) until one of the following
conditions has been met:
(1) Observed exiting. The animal is observed exiting the mitigation
zone;
(2) Thought to have exited. The animal is thought to have exited
the mitigation zone based on a determination of its course, speed, and
movement relative to the firing ship;
(3) Clear from additional sightings. The mitigation zone has been
clear from any additional sightings for 30 min; or
[[Page 49760]]
(4) Firing ship transit. For mobile activities, the firing ship has
transited a distance equal to double that of the mitigation zone size
beyond the location of the last sighting.
(iv) Explosive large-caliber projectiles. Gunnery activities using
explosive large-caliber projectiles. Mitigation applies to activities
using a surface target.
(A) Number of Lookouts and observation platform. One Lookout must
be on the vessel or aircraft conducting the activity. Depending on the
activity, the Lookout could be the same as the one described in
``Weapons firing noise'' in paragraph (a)(1)(iii)(A) of this section.
If additional platforms are participating in the activity, Navy
personnel positioned in those assets (e.g., safety observers,
evaluators) must support observing the mitigation zone for marine
mammals while performing their regular duties.
(B) Mitigation zones. 1,000 yd (914.4 m) around the intended impact
location.
(C) Prior to activity. Prior to the initial start of the activity
(e.g., when maneuvering on station), Navy personnel must observe the
mitigation zone for floating vegetation and marine mammals; if floating
vegetation or a marine mammal is observed, Navy personnel must relocate
or delay the start of firing until the mitigation zone is clear of
floating vegetation or until the conditions in paragraph (a)(1)(iv)(E)
of this section are met for marine mammals.
(D) During activity. During the activity, Navy personnel must
observe the mitigation zone for marine mammals; if a marine mammal is
observed, Navy personnel must cease firing.
(E) Commencement/recommencement conditions after a marine mammal
sighting before or during the activity. Navy personnel must allow a
sighted marine mammal to leave the mitigation zone prior to the initial
start of the activity (by delaying the start) or during the activity
(by not recommencing firing) until one of the following conditions has
been met:
(1) Observed exiting. The animal is observed exiting the mitigation
zone;
(2) Thought to have exited. The animal is thought to have exited
the mitigation zone based on a determination of its course, speed, and
movement relative to the intended impact location;
(3) Clear of additional sightings. The mitigation zone has been
clear from any additional sightings for 30 minutes; or,
(4) Impact location transit. For activities using mobile targets,
the intended impact location has transited a distance equal to double
that of the mitigation zone size beyond the location of the last
sighting.
(F) After activity. After completion of the activity (e.g., prior
to maneuvering off station), Navy personnel must, when practical (e.g.,
when platforms are not constrained by fuel restrictions or mission-
essential follow-on commitments), observe for marine mammals in the
vicinity of where detonations occurred; if any injured or dead marine
mammals are observed, Navy personnel must follow established incident
reporting procedures. If additional platforms are supporting this
activity (e.g., providing range clearance), Navy personnel positioned
on these Navy assets must assist in the visual observation of the area
where detonations occurred.
(v) Explosive bombs.
(A) Number of Lookouts and observation platform. One Lookout must
be positioned in an aircraft conducting the activity. If additional
platforms are participating in the activity, Navy personnel positioned
in those assets (e.g., safety observers, evaluators) must support
observing the mitigation zone for marine mammals while performing their
regular duties.
(B) Mitigation zone. 2,500 yd (2,286 m) around the intended target.
(C) Prior to activity. Prior to the initial start of the activity
(e.g., when arriving on station), Navy personnel must observe the
mitigation zone for floating vegetation and marine mammals; if floating
vegetation or a marine mammal is observed, Navy personnel must relocate
or delay the start of bomb deployment until the mitigation zone is
clear of floating vegetation or until the conditions in paragraph
(a)(1)(v)(E) of this section are met for marine mammals.
(D) During activity. During the activity (e.g., during target
approach), Navy personnel must observe the mitigation zone for marine
mammals; if a marine mammal is observed, Navy personnel must cease bomb
deployment.
(E) Commencement/recommencement conditions after a marine mammal
sighting before or during the activity. Navy personnel must allow a
sighted marine mammal to leave the mitigation zone prior to the initial
start of the activity (by delaying the start) or during the activity
(by not recommencing bomb deployment) until one of the following
conditions has been met:
(1) Observed exiting. The animal is observed exiting the mitigation
zone;
(2) Thought to have exited. The animal is thought to have exited
the mitigation zone based on a determination of its course, speed, and
movement relative to the intended target;
(3) Clear from additional sightings. The mitigation zone has been
clear from any additional sightings for 10 min; or
(4) Intended target transit. For activities using mobile targets,
the intended target has transited a distance equal to double that of
the mitigation zone size beyond the location of the last sighting.
(F) After activity. After completion of the activity (e.g., prior
to maneuvering off station), Navy personnel must, when practical (e.g.,
when platforms are not constrained by fuel restrictions or mission-
essential follow-on commitments), observe for marine mammals in the
vicinity of where detonations occurred; if any injured or dead marine
mammals are observed, Navy personnel must follow established incident
reporting procedures. If additional platforms are supporting this
activity (e.g., providing range clearance), Navy personnel positioned
on these Navy assets must assist in the visual observation of the area
where detonations occurred.
(vi) Vessel movement. The mitigation will not be applied if: the
vessel's safety is threatened; the vessel is restricted in its ability
to maneuver (e.g., during launching and recovery of aircraft or landing
craft, during towing activities, when mooring); the vessel is submerged
or operated autonomously; or when impractical based on mission
requirements (e.g., during Vessel Visit, Board, Search, and Seizure
activities as military personnel from ships or aircraft board suspect
vessels).
(A) Number of Lookouts and observation platform. One or more
Lookouts must be on the underway vessel. If additional watch personnel
are positioned on the underway vessel, those personnel (e.g., persons
assisting with navigation or safety) must support observing for marine
mammals while performing their regular duties.
(B) Mitigation zone.
(1) Whales. 500 yd (457.2 m) around the vessel for whales.
(2) Marine mammals other than whales. 200 yd (182.9 m) around the
vessel for all marine mammals other than whales (except those
intentionally swimming alongside or closing in to swim alongside
vessels, such as bow-riding or wake-riding dolphins).
(C) When underway. Navy personnel will observe the direct path of
the vessel and waters surrounding the vessel for marine mammals. If a
marine mammal is observed in the direct path of the vessel, Navy
personnel will maneuver the vessel as necessary to maintain the
appropriate mitigation zone distance. If
[[Page 49761]]
a marine mammal is observed within waters surrounding the vessel, Navy
personnel will maintain situational awareness of that animal's
position. Based on the animal's course and speed relative to the
vessel's path, Navy personnel will maneuver the vessel as necessary to
ensure that the appropriate mitigation zone distance from the animal
continues to be maintained.
(D) Incident reporting procedures. If a marine mammal vessel strike
occurs, Navy personnel must follow the established incident reporting
procedures.
(vii) Towed in-water devices. Mitigation applies to devices that
are towed from a manned surface platform or manned aircraft, or when a
manned support craft is already participating in an activity involving
in-water devices being towed by unmanned platforms. The mitigation will
not be applied if the safety of the towing platform or in-water device
is threatened.
(A) Number of Lookouts and observation platform. One Lookout must
be positioned on a manned towing platform or support craft.
(B) Mitigation zone. 250 yd (228.6 m) around the towed in-water
device for marine mammals (except those intentionally swimming
alongside or choosing to swim alongside towing vessels, such as bow-
riding or wake-riding dolphins).
(C) During activity. During the activity (i.e., when towing an in-
water device), Navy personnel must observe the mitigation zone for
marine mammals; if a marine mammal is observed, Navy personnel must
maneuver to maintain distance.
(viii) Small-, medium-, and large-caliber non-explosive practice
munitions. Gunnery activities using small-, medium-, and large-caliber
non-explosive practice munitions. Mitigation applies to activities
using a surface target.
(A) Number of Lookouts and observation platform. One Lookout must
be positioned on the platform conducting the activity. Depending on the
activity, the Lookout could be the same as the one described for
``Weapons firing noise'' in paragraph (a)(1)(iii)(A) of this section.
(B) Mitigation zone. 200 yd (182.9 m) around the intended impact
location.
(C) Prior to activity. Prior to the initial start of the activity
(e.g., when maneuvering on station), Navy personnel must observe the
mitigation zone for floating vegetation and marine mammals; if floating
vegetation or a marine mammal is observed, Navy personnel must relocate
or delay the start of firing until the mitigation zone is clear of
floating vegetation or until the conditions in paragraph
(a)(1)(viii)(E) of this section are met for marine mammals.
(D) During activity. During the activity, Navy personnel must
observe the mitigation zone for marine mammals; if a marine mammal is
observed, Navy personnel must cease firing.
(E) Commencement/recommencement conditions after a marine mammal
sighting before or during the activity. Navy personnel must allow a
sighted marine mammal to leave the mitigation zone prior to the initial
start of the activity (by delaying the start) or during the activity
(by not recommencing firing) until one of the following conditions has
been met:
(1) Observed exiting. The animal is observed exiting the mitigation
zone;
(2) Thought to have exited. The animal is thought to have exited
the mitigation zone based on a determination of its course, speed, and
movement relative to the intended impact location;
(3) Clear of additional sightings. The mitigation zone has been
clear from any additional sightings for 10 minutes for aircraft-based
firing or 30 minutes for vessel-based firing; or
(4) Impact location transit. For activities using a mobile target,
the intended impact location has transited a distance equal to double
that of the mitigation zone size beyond the location of the last
sighting.
(ix) Non-explosive bombs. Non-explosive bombs.
(A) Number of Lookouts and observation platform. One Lookout must
be positioned in an aircraft.
(B) Mitigation zone. 1,000 yd (914.4 m) around the intended target.
(C) Prior to activity. Prior to the initial start of the activity
(e.g., when arriving on station), Navy personnel must observe the
mitigation zone for floating vegetation and marine mammals; if floating
vegetation or a marine mammal is observed, Navy personnel must relocate
or delay the start of bomb deployment until the mitigation zone is
clear of floating vegetation or until the conditions in paragraph
(a)(1)(ix)(E) of this section are met for marine mammals.
(D) During activity. During the activity (e.g., during approach of
the target), Navy personnel must observe the mitigation zone for marine
mammals and, if a marine mammal is observed, Navy personnel must cease
bomb deployment.
(E) Commencement/recommencement conditions after a marine mammal
sighting prior to or during the activity. Navy personnel must allow a
sighted marine mammal to leave the mitigation zone prior to the initial
start of the activity (by delaying the start) or during the activity
(by not recommencing bomb deployment) until one of the following
conditions has been met:
(1) Observed exiting. The animal is observed exiting the mitigation
zone;
(2) Thought to have exited. The animal is thought to have exited
the mitigation zone based on a determination of its course, speed, and
movement relative to the intended target;
(3) Clear from additional sightings. The mitigation zone has been
clear from any additional sightings for 10 min; or
(4) Intended target transit. For activities using mobile targets,
the intended target has transited a distance equal to double that of
the mitigation zone size beyond the location of the last sighting.
(2) Mitigation areas. In addition to procedural mitigation, Navy
personnel must implement mitigation measures within mitigation areas to
avoid or reduce potential impacts on marine mammals.
(i) North Pacific Right Whale Mitigation Area. Figure 1 shows the
location of the mitigation area.
(A) Surface ship hull-mounted MF1 mid-frequency active sonar. From
June 1-September 30 within the North Pacific Right Whale Mitigation
Area, Navy personnel must not use surface ship hull-mounted MF1 mid-
frequency active sonar during training.
(B) National security exception. Should national security require
that the Navy cannot comply with the restrictions in paragraph
(a)(2)(i)(A) of this section, Navy personnel must obtain permission
from the designated Command, U.S. Third Fleet Command Authority, prior
to commencement of the activity. Navy personnel must provide NMFS with
advance notification and include information about the event in its
annual activity reports to NMFS.
(ii) Continental Shelf and Slope Mitigation Area. Figure 1 shows
the location of the mitigation area.
(A) Explosives. Navy personnel must not detonate explosives below
10,000 ft. altitude (including at the water surface) in the Continental
Shelf and Slope Mitigation Area during training.
(B) National security exception. Should national security require
that the Navy cannot comply with the restrictions in paragraph
(a)(2)(ii)(A) of this section, Navy personnel must obtain permission
from the designated Command, U.S. Third Fleet Command Authority, prior
to commencement of
[[Page 49762]]
the activity. Navy personnel must provide NMFS with advance
notification and include information about the event in its annual
activity reports to NMFS.
(iii) Pre-event Awareness Notifications in the Temporary Maritime
Activities Area. The Navy must issue pre-event awareness messages to
alert vessels and aircraft participating in training activities within
the TMAA to the possible presence of concentrations of large whales on
the continental shelf and slope. Occurrences of large whales may be
higher over the continental shelf and slope relative to other areas of
the TMAA. Large whale species in the TMAA include, but are not limited
to, fin whale, blue whale, humpback whale, gray whale, North Pacific
right whale, sei whale, and sperm whale. To maintain safety of
navigation and to avoid interactions with marine mammals, the Navy must
instruct personnel to remain vigilant to the presence of large whales
that may be vulnerable to vessel strikes or potential impacts from
training activities. Additionally, Navy personnel must use the
information from the awareness notification messages to assist their
visual observation of applicable mitigation zones during training
activities and to aid in the implementation of procedural mitigation.
BILLING CODE 3510-22-P
[[Page 49763]]
[GRAPHIC] [TIFF OMITTED] TP11AU22.005
BILLING CODE 3510-22-C
(b) [Reserved]
Sec. 218.155 Requirements for monitoring and reporting.
(a) Unauthorized take. Navy personnel must notify NMFS immediately
(or as soon as operational security considerations allow) if the
specified activity identified in Sec. 218.150 is thought to have
resulted in the mortality or serious injury of any marine mammals, or
in any Level A harassment or Level B harassment of marine mammals not
authorized under this subpart.
(b) Monitoring and reporting under the LOA. The Navy must conduct
all monitoring and reporting required under the LOA, including abiding
by the U.S. Navy's Marine Species Monitoring Program. Details on
program goals, objectives, project selection process, and current
projects are available at www.navymarinespeciesmonitoring.us.
(c) Notification of injured, live stranded, or dead marine mammals.
Navy personnel must consult the Notification and Reporting Plan, which
sets out notification, reporting, and
[[Page 49764]]
other requirements when dead, injured, or live stranded marine mammals
are detected. The Notification and Reporting Plan is available at
https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.
(d) Annual GOA Marine Species Monitoring Report. The Navy must
submit an annual report of the GOA Study Area monitoring, which will be
included in a Pacific-wide monitoring report and include results
specific to the GOA Study Area, describing the implementation and
results from the previous calendar year. Data collection methods must
be standardized across Pacific Range Complexes including the Mariana
Islands Training and Testing (MITT), Hawaii-Southern California
Training and Testing (HSTT), Northwest Training and Testing (NWTT), and
Gulf of Alaska (GOA) Study Areas to allow for comparison among
different geographic locations. The report must be submitted to the
Director, Office of Protected Resources, NMFS, either within 3 months
after the end of the calendar year, or within 3 months after the
conclusion of the monitoring year, to be determined by the adaptive
management process. NMFS will submit comments or questions on the
report, if any, within 3 months of receipt. The report will be
considered final after the Navy has addressed NMFS' comments, or 3
months after submittal if NMFS does not provide comments on the report.
This report will describe progress of knowledge made with respect to
intermediate scientific objectives within the GOA Study Area associated
with the Integrated Comprehensive Monitoring Program (ICMP). Similar
study questions must be treated together so that progress on each topic
can be summarized across all Navy ranges. The report need not include
analyses and content that does not provide direct assessment of
cumulative progress on the monitoring plan study questions. This will
continue to allow the Navy to provide a cohesive monitoring report
covering multiple ranges (as per ICMP goals), rather than entirely
separate reports for the GOA, NWTT, HSTT, and MITT Study Areas.
(e) GOA Annual Training Report. Each year in which training
activities are conducted in the GOA Study Area, the Navy must submit
one preliminary report (Quick Look Report) to NMFS detailing the status
of applicable sound sources within 21 days after the completion of the
training activities in the GOA Study Area. Each year in which
activities are conducted, the Navy must also submit a detailed report
(GOA Annual Training Report) to the Director, Office of Protected
Resources, NMFS, within 3 months after completion of the training
activities. NMFS must submit comments or questions on the report, if
any, within one month of receipt. The report will be considered final
after the Navy has addressed NMFS' comments, or one month after
submittal if NMFS does not provide comments on the report. The annual
reports must contain information about the Major Training Exercise
(MTE), including the information listed in paragraphs (e)(1) and (2) of
this section. The annual report, which is only required during years in
which activities are conducted, must also contain cumulative sonar and
explosive use quantity from previous years' reports through the current
year. Additionally, if there were any changes to the sound source
allowance in the reporting year, or cumulatively, the report must
include a discussion of why the change was made and include analysis to
support how the change did or did not affect the analysis in the GOA
SEIS/OEIS and MMPA final rule. The analysis in the detailed report must
be based on the accumulation of data from the current year's report and
data collected from previous annual reports. The final annual/close-out
report at the conclusion of the authorization period (year seven) will
also serve as the comprehensive close-out report and include both the
final year annual use compared to annual authorization as well as a
cumulative 7-year annual use compared to 7-year authorization. This
report must also note any years in which training did not occur. NMFS
must submit comments on the draft close-out report, if any, within 3
months of receipt. The report will be considered final after the Navy
has addressed NMFS' comments, or 3 months after the submittal if NMFS
does not provide comments. Information included in the annual reports
may be used to inform future adaptive management of activities within
the GOA Study Area. In addition to the information discussed above, the
GOA Annual Training Report must include the following information.
(1) MFAS/HFAS. The Navy must submit the following information for
the MTE conducted in the GOA Study Area.
(i) Exercise Information (for each MTE):
(A) Exercise designator.
(B) Date that exercise began and ended.
(C) Location.
(D) Number and types of active sources used in the exercise.
(E) Number and types of passive acoustic sources used in exercise.
(F) Number and types of vessels, aircraft, etc., participating in
exercise.
(G) Total hours of observation by Lookouts.
(H) Total hours of all active sonar source operation.
(I) Total hours of each active sonar source bin.
(J) Wave height (high, low, and average during exercise).
(ii) Individual marine mammal sighting information for each
sighting in each exercise where mitigation was implemented:
(A) Date/Time/Location of sighting.
(B) Species (if not possible, indication of whale/dolphin/
pinniped).
(C) Number of individuals.
(D) Initial Detection Sensor (e.g., sonar or Lookout).
(E) Indication of specific type of platform observation made from
(including, for example, what type of surface vessel or testing
platform).
(F) Length of time observers maintained visual contact with marine
mammal.
(G) Sea state.
(H) Visibility.
(I) Sound source in use at the time of sighting.
(J) Indication of whether animal was less than 200 yd (182.9 m),
200 to 500 yd (182.9 to 457.2 m), 500 to 1,000 yd (457.2 to 914.4 m),
1,000 to 2,000 yd (914.4 to 1,828.8 m), or greater than 2,000 yd
(1,828.8 m) from sonar source.
(K) Sonar mitigation implementation. Whether operation of sonar
sensor was delayed, or sonar was powered or shut down, and how long the
delay was.
(L) Bearing, direction, and motion. If source in use is hull-
mounted, true bearing of animal from ship, true direction of ship's
travel, and estimation of animal's motion relative to ship (opening,
closing, parallel).
(M) Observed behavior. Lookouts shall report, in plain language and
without trying to categorize in any way, the observed behavior of the
animals (such as animal closing to bow ride, paralleling course/speed,
floating on surface and not swimming, etc.) and if any calves present.
(iii) Mitigation effectiveness evaluation. An evaluation (based on
data gathered during all of the MTEs) of the effectiveness of
mitigation measures designed to minimize the received level to which
marine mammals may be exposed. This evaluation shall identify the
specific observations that support any conclusions the Navy reaches
about the effectiveness of the mitigation.
(2) Summary of sources used. (i) This section shall include the
following information summarized from the authorized sound sources used
in all training events:
[[Page 49765]]
(A) Total hours. Total annual hours or quantity (per the LOA) of
each bin of sonar or other non-impulsive source; and
(B) Number of explosives. Total annual number of each type of
explosive exercises and total annual expended/detonated rounds (bombs,
large-caliber projectiles) for each explosive bin.
Sec. 218.156 Letters of Authorization.
(a) To incidentally take marine mammals pursuant to this subpart,
the Navy must apply for and obtain an LOA in accordance with Sec.
216.106 of this chapter.
(b) An LOA, unless suspended or revoked, may be effective for a
period of time not to exceed the expiration date of this subpart.
(c) If an LOA expires prior to the expiration date of this subpart,
the Navy may apply for and obtain a renewal of the LOA.
(d) In the event of projected changes to the activity or to
mitigation, monitoring, or reporting (excluding changes made pursuant
to the adaptive management provision of Sec. 218.157(c)(1)) required
by an LOA issued under this subpart, the Navy must apply for and obtain
a modification of the LOA as described in Sec. 218.157.
(e) Each LOA will set forth:
(1) Permissible methods of incidental taking;
(2) Geographic areas for incidental taking;
(3) Means of effecting the least practicable adverse impact (i.e.,
mitigation) on the species and stocks of marine mammals and their
habitat; and
(4) Requirements for monitoring and reporting.
(f) Issuance of the LOA will be based on a determination that the
level of taking is consistent with the findings made for the total
taking allowable under this subpart.
(g) Notice of issuance or denial of the LOA will be published in
the Federal Register within 30 days of a determination.
Sec. 218.157 Renewals and modifications of Letters of Authorization.
(a) An LOA issued under Sec. Sec. 216.106 of this chapter and
218.156 for the activity identified in Sec. 218.150(c) may be renewed
or modified upon request by the applicant, provided that:
(1) The planned specified activity and mitigation, monitoring, and
reporting measures, as well as the anticipated impacts, are the same as
those described and analyzed for this subpart (excluding changes made
pursuant to the adaptive management provision in paragraph (c)(1) of
this section); and
(2) NMFS determines that the mitigation, monitoring, and reporting
measures required by the previous LOA were implemented.
(b) For LOA modification or renewal requests by the applicant that
include changes to the activity or to the mitigation, monitoring, or
reporting measures (excluding changes made pursuant to the adaptive
management provision in paragraph (c)(1) of this section) that do not
change the findings made for this subpart or result in no more than a
minor change in the total estimated number of takes (or distribution by
species or stock or years), NMFS may publish a notice of planned LOA in
the Federal Register, including the associated analysis of the change,
and solicit public comment before issuing the LOA.
(c) An LOA issued under Sec. Sec. 216.106 of this chapter and
218.156 may be modified by NMFS under the following circumstances:
(1) After consulting with the Navy regarding the practicability of
the modifications, NMFS may modify (including adding or removing
measures) the existing mitigation, monitoring, or reporting measures if
doing so creates a reasonable likelihood of more effectively
accomplishing the goals of the mitigation and monitoring.
(i) Possible sources of data that could contribute to the decision
to modify the mitigation, monitoring, or reporting measures in an LOA
include:
(A) Results from the Navy's monitoring from the previous year(s);
(B) Results from other marine mammal and/or sound research or
studies; or
(C) Any information that reveals marine mammals may have been taken
in a manner, extent, or number not authorized by this subpart or a
subsequent LOA.
(ii) If, through adaptive management, the modifications to the
mitigation, monitoring, or reporting measures are substantial, NMFS
will publish a notice of planned LOA in the Federal Register and
solicit public comment.
(2) If NMFS determines that an emergency exists that poses a
significant risk to the well-being of the species or stocks of marine
mammals specified in LOAs issued pursuant to Sec. Sec. 216.106 of this
chapter and 218.156, an LOA may be modified without prior notice or
opportunity for public comment. Notice would be published in the
Federal Register within 30 days of the action.
Sec. 218.158 [Reserved]
[FR Doc. 2022-16509 Filed 8-10-22; 8:45 am]
BILLING CODE 3510-22-P
