Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Office of Naval Research's Arctic Research Activities in the Beaufort and Chukchi Seas (Year 7), 66068-66091 [2024-18130]
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Federal Register / Vol. 89, No. 157 / Wednesday, August 14, 2024 / Notices
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
[RTID 0648–XE175]
Marine Mammals; File No. 27911
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
ACTION: Notice; receipt of application.
AGENCY:
Notice is hereby given that
Ari Friedlaender, Ph.D., University of
California at Santa Cruz, 115 McAllister
Way, Santa Cruz, CA 95060, has applied
in due form for a permit to conduct
research on eight whale species.
DATES: Written comments must be
received on or before September 13,
2024.
SUMMARY:
The application and related
documents are available for review by
selecting ‘‘Records Open for Public
Comment’’ from the ‘‘Features’’ box on
the Applications and Permits for
Protected Species home page, https://
apps.nmfs.noaa.gov, and then selecting
File No. 27911 from the list of available
applications. These documents are also
available upon written request via email
to NMFS.Pr1Comments@noaa.gov.
Written comments on this application
should be submitted via email to
NMFS.Pr1Comments@noaa.gov. Please
include File No. 27911 in the subject
line of the email comment.
Those individuals requesting a public
hearing should submit a written request
via email to NMFS.Pr1Comments@
noaa.gov. The request should set forth
the specific reasons why a hearing on
this application would be appropriate.
FOR FURTHER INFORMATION CONTACT:
Amy Hapeman or Shasta McClenahan,
Ph.D., (301) 427–8401.
SUPPLEMENTARY INFORMATION: The
subject permit is requested under the
authority of the Marine Mammal
Protection Act of 1972, as amended
(MMPA; 16 U.S.C. 1361 et seq.), the
regulations governing the taking and
importing of marine mammals (50 CFR
part 216), the Endangered Species Act of
1973, as amended (ESA; 16 U.S.C. 1531
et seq.), and the regulations governing
the taking, importing, and exporting of
endangered and threatened species (50
CFR parts 222–226).
The applicant proposes to conduct
research on eight species of whales in
the Southern Ocean to understand their
population demography, health,
behavior, and ecology. Species targeted
for study are: Antarctic minke
(Balaenoptera bonaerensis), Arnoux’s
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ADDRESSES:
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beaked (B. arnouxii), endangered blue
(B. musculus), endangered fin (B.
physalus), humpback (Megaptera
novaeangliae), killer (Orcinus orca),
endangered sei (B. borealis), endangered
Southern right (Eubalaena australis)
whales. Researchers would operate
vessels and unmanned aircraft systems
(UAS) to count, observe, photograph,
biopsy sample, tag (suction-cup, dart, or
deep implant), and track whales.
Suction cup tags would be deployed by
pole or UAS. A small number of adult
humpback whales would receive two
tag types at a time. Prey mapping would
occur in the vicinity of some tagged
whales. Biopsy samples would be
imported into the United States for
analysis and curation. See the
application for take numbers by species.
The permit would be valid for 5 years.
In compliance with the National
Environmental Policy Act of 1969 (42
U.S.C. 4321 et seq.), an initial
determination has been made that the
activity proposed is categorically
excluded from the requirement to
prepare an environmental assessment or
environmental impact statement.
Concurrent with the publication of
this notice in the Federal Register,
NMFS is forwarding copies of the
application to the Marine Mammal
Commission and its Committee of
Scientific Advisors.
Dated: August 6, 2024.
Julia M. Harrison,
Chief, Permits and Conservation Division,
Office of Protected Resources, National
Marine Fisheries Service.
[FR Doc. 2024–17968 Filed 8–13–24; 8:45 am]
BILLING CODE 3510–22–P
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
[RTID 0648–XE173]
Takes of Marine Mammals Incidental to
Specified Activities; Taking Marine
Mammals Incidental to the Office of
Naval Research’s Arctic Research
Activities in the Beaufort and Chukchi
Seas (Year 7)
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
ACTION: Notice; proposed incidental
harassment authorization; request for
comments on proposed authorization
and possible renewal.
AGENCY:
NMFS has received a request
from the Office of Naval Research (ONR)
for authorization to take marine
SUMMARY:
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mammals incidental to Arctic Research
Activities (ARA) in the Beaufort Sea and
eastern Chukchi Sea. Pursuant to the
Marine Mammal Protection Act
(MMPA), NMFS is requesting comments
on its proposal to issue an incidental
harassment authorization (IHA) to
incidentally take marine mammals
during the specified activities. NMFS is
also requesting comments on a possible
one-time, 1-year renewal that could be
issued under certain circumstances and
if all requirements are met, as described
in Request for Public Comments at the
end of this notice. NMFS will consider
public comments prior to making any
final decision on the issuance of the
requested MMPA authorization and
agency responses will be summarized in
the final notice of our decision. The
ONR’s activities are considered 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 13,
2024.
ADDRESSES: Comments should be
addressed to Jolie Harrison, Chief,
Permits and Conservation Division,
Office of Protected Resources, National
Marine Fisheries Service and should be
submitted via email to ITP.clevenstine@
noaa.gov. Electronic copies of the
application and supporting documents,
as well as a list of the references cited
in this document, may be obtained
online at: https://
www.fisheries.noaa.gov/national/
marine-mammal-protection/incidentaltake-authorizations-military-readinessactivities. In case of problems accessing
these documents, please call the contact
listed below.
Instructions: NMFS is not responsible
for comments sent by any other method,
to any other address or individual, or
received after the end of the comment
period. Comments, including all
attachments, must not exceed a 25megabyte file size. All comments
received are a part of the public record
and will generally be posted online at
https://www.fisheries.noaa.gov/permit/
incidental-take-authorizations-undermarine-mammal-protection-act without
change. All personal identifying
information (e.g., name, address)
voluntarily submitted by the commenter
may be publicly accessible. Do not
submit confidential business
information or otherwise sensitive or
protected information.
FOR FURTHER INFORMATION CONTACT:
Alyssa Clevenstine, Office of Protected
Resources, NMFS, (301) 427–8401.
SUPPLEMENTARY INFORMATION:
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Background
The MMPA prohibits the ‘‘take’’ of
marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and
(D) of the MMPA (16 U.S.C. 1361 et
seq.) 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, a notice of a proposed IHA
is provided to the public for review.
Authorization for incidental takings
shall be granted if NMFS finds that the
taking will have a negligible impact on
the species or stock(s) and will not have
an unmitigable adverse impact on the
availability of the species or stock(s) 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 the species or stocks for
taking for certain subsistence uses
(referred to in shorthand as
‘‘mitigation’’); and requirements
pertaining to the monitoring and
reporting of the takings. The definitions
of all applicable MMPA statutory terms
cited above are included in the relevant
sections below.
The 2004 NDAA (Pub. L. 108–136)
removed the ‘‘small numbers’’ and
‘‘specified geographical region’’
limitations indicated above and
amended the definition of ‘‘harassment’’
as applied to a ‘‘military readiness
activity.’’ The activity for which
incidental take of marine mammals is
being requested qualifies as a military
readiness activity.
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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 review our
proposed action (i.e., the issuance of an
IHA) with respect to potential impacts
on the human environment.
In 2018, the U.S. Navy prepared an
Overseas Environmental Assessment
(OEA) analyzing the project. Prior to
issuing the IHA for the first year of this
project, NMFS reviewed the 2018 EA
and the public comments received,
determined that a separate NEPA
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analysis was not necessary, and
subsequently adopted the document and
issued a NMFS Finding of No
Significant Impact (FONSI) in support
of the issuance of an IHA (83 FR 48799,
September 27, 2018).
In 2019, the Navy prepared a
supplemental OEA. Prior to issuing the
IHA in 2019, NMFS reviewed the
supplemental OEA and the public
comments received, determined that a
separate NEPA analysis was not
necessary, and subsequently adopted
the document and issued a NMFS
FONSI in support of the issuance of an
IHA (84 FR 50007, September 24, 2019).
In 2020, the Navy submitted a request
for a renewal of the 2019 IHA. Prior to
issuing the renewal IHA, NMFS
reviewed ONR’s application and
determined that the proposed action
was identical to that considered in the
previous IHA. Because no significantly
new circumstances or information
relevant to any environmental concerns
had been identified, NMFS determined
that the preparation of a new or
supplemental NEPA document was not
necessary and relied on the
supplemental OEA and FONSI from
2019 when issuing the renewal IHA in
2020 (85 FR 41560, July 10, 2020).
In 2021, the Navy submitted a request
for an IHA for incidental take of marine
mammals during continuation of ARA.
NMFS reviewed the Navy’s OEA and
determined it to be sufficient for taking
into consideration the direct, indirect,
and cumulative effects to the human
environment resulting from
continuation of the ARA. NMFS
subsequently adopted that OEA and
signed a FONSI (86 FR 54931, October
5, 2021).
In 2022, the Navy submitted a request
for an IHA for incidental take of marine
mammals during continuation of ARA
and prepared an OEA analyzing the
project. Prior to issuing the IHA for the
project, we reviewed the 2022–2025
OEA and the public comments received,
determined that a separate NEPA
analysis was not necessary, and
subsequently adopted the document and
issued our own FONSI in support of the
issuance of an IHA (87 FR 57458,
September 20, 2022).
In 2023, the ONR requested a renewal
of the 2022 IHA for ongoing ARA from
September 2023 to September 2024, and
the 2022 IHA monitoring report. Prior to
issuing the renewal IHA, NMFS
reviewed ONR’s application and
determined that the proposed action
was identical to that considered in the
previous IHA. Because no significantly
new circumstances or information
relevant to any environmental concerns
were identified, NMFS determined that
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the preparation of a new or
supplemental NEPA document was not
necessary and relied on the
supplemental OEA and FONSI from
2022 when issuing the renewal IHA in
2023 (88 FR 65657, September 18,
2023).
Accordingly, NMFS preliminarily has
determined to adopt the Navy’s OEA for
ONR ARA in the Beaufort and Chukchi
Seas 2022–2025, provided our
independent evaluation of the
document finds that it includes
adequate information analyzing the
effects on the human environment of
issuing the IHA. NMFS is a not
cooperating agency on the U.S. Navy’s
OEA.
We will review all comments
submitted in response to this notice
prior to concluding our NEPA process
or making a final decision on the IHA
request.
Summary of Request
On March 29, 2024, NMFS received a
request from the ONR for an IHA to take
marine mammals incidental to ARA in
the Beaufort and Chukchi Seas.
Following NMFS’ review of the
application, the ONR submitted a
revised version on July 23, 2024. The
application was deemed adequate and
complete on August 5, 2024. The ONR’s
request is for take of beluga whales and
ringed seals by Level B harassment only.
Neither the ONR nor NMFS expect
serious injury or mortality to result from
this activity and, therefore, an IHA is
appropriate.
This proposed IHA would cover the
seventh year of a larger project for
which ONR obtained prior IHAs and
renewal IHAs (83 FR 48799, September
27, 2018; 84 FR 50007, September 24,
2019; 85 FR 53333, August 28, 2020; 86
FR 54931, October 5, 2021; 87 FR 57458,
September 20, 2022; 88 FR 65657,
September 18, 2023). ONR has complied
with all the requirements (e.g.,
mitigation, monitoring, and reporting) of
the previous IHAs.
Description of Proposed Activity
Overview
The ONR proposes to conduct
scientific experiments in support of
ARA using active acoustic sources
within the Beaufort and Chukchi Seas.
Project activities involve acoustic
testing and a multi-frequency navigation
system concept test using left-behind
active acoustic sources. The proposed
experiments involve the deployment of
moored, drifting, and ice-tethered active
acoustic sources from the Research
Vessel (R/V) Sikuliaq. Recovery of
equipment may be from R/V Sikuliaq,
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U.S. Coast Guard Cutter (CGC) HEALY,
or another vessel, and icebreaking may
be required. Underwater sound from the
active acoustic sources and noise from
icebreaking may result in Level B
harassment of marine mammals.
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Dates and Duration
The proposed action would occur
from September 2024 through
September 2025 and include up to two
research cruises. Acoustic testing would
take place during the cruises, with the
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first cruise beginning September 2,
2024, and a potential second cruise
occurring in summer or fall 2025, which
may include up to 8 days of icebreaking
activities.
Geographic Region
The proposed action would occur
across the U.S. Exclusive Economic
Zone (EEZ) in the Beaufort and Chukchi
Seas, partially in the high seas north of
Alaska, the Global Commons, and
within a part of the Canadian EEZ (in
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which the appropriate permits would be
obtained by the Navy) (figure 1). The
proposed action would primarily occur
in the Beaufort Sea but the analysis
considers the drifting of active sources
on buoys into the eastern portion of the
Chukchi Sea. The closest point of the
study area to the Alaska coast is 204
kilometers (km; 110 nautical miles
(nm)). The proposed study area is
approximately 639,267 square
kilometers (km2).
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Detailed Description of the Specified
Activity
The ONR ARA Global Prediction
Program supports two major projects:
Stratified Ocean Dynamics of the Arctic
(SODA) and Arctic Mobile Observing
System (AMOS). The SODA and AMOS
projects have been previously discussed
in association with previously issued
IHAs (83 FR 40234, August 14, 2018; 84
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FR 37240, July 31, 2019). However, only
activities relating to the AMOS project
will occur during the period covered by
this proposed action.
The proposed action constitutes the
development of a modified system
under the ONR AMOS involving verylow-, low-, and mid-frequency (VLF, LF,
MF) transmissions (35 Hertz (Hz), 900
Hz, and 10 kilohertz (kHz),
respectively). The AMOS project
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utilizes acoustic sources and receivers
to provide a means of performing underice navigation for gliders and unmanned
undersea vehicles (UUVs). This would
allow for the possibility of year-round
scientific observations of the
environment in the Arctic. As an
environment that is particularly affected
by climate change, year-round
observations under a variety of ice
conditions are required to study the
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Figure I -Arctic Research Activities Study Area and Mooring Locations
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effects of this changing environment for
military readiness, as well as the
implications of environmental change to
humans and animals. VLF technology is
important in extending the range of
navigation systems and has the potential
to allow for development and use of
navigational systems that would not be
heard by some marine mammal species
and, therefore, would be less impactful
overall.
Up to six moorings (four fixed
acoustic navigation sources transmitting
at 900 Hz, two fixed VLF sources
transmitting at 35 Hz) and two drifting
ice gateway buoys (IGBs) would be
configured with active acoustic sources
and would operate for a period of up to
1 year. Four gliders with passive
acoustics would be used to support
drifting IGBs. No UUV use is planned
during the September 2024 research
cruise; however, there is the potential
for one UUV (without active acoustic
sources) to be deployed and up to 8
days of icebreaking activities to occur
on a potential research cruise in
summer/fall 2025, which would require
the use of a vessel with ice-breaking
capabilities (e.g., CGC HEALY).
During the research cruise, acoustic
sources would be deployed from the
vessel for intermittent testing of the
system components, which would take
place in the vicinity of the source
locations (figure 1). During this testing,
35 Hz, 900 Hz, 10 kHz, and acoustic
modems would be employed. The six
fixed moorings would be anchored on
the seabed and held in the water
column with subsurface buoys.
Autonomous vehicles would be able
to navigate by receiving acoustic signals
from multiple locations and
triangulating. This is needed for
vehicles that are under ice and cannot
communicate with satellites. Source
transmits would be offset by 15 minutes
from each other (i.e., sources would not
be transmitting at the same time). All
navigation sources would be recovered.
The purpose of the navigation sources is
to orient UUVs and gliders in situations
when they are under ice and cannot
communicate with satellites.
The proposed action would utilize
non-impulsive acoustic sources,
although not all sources will cause take
of marine mammals (tables 1, 2). Marine
mammal takes would arise from the
operation of non-impulsive active
sources. Although not currently
planned, icebreaking could occur as part
of this proposed action if a research
vessel needs to return to the study area
before the end of the IHA period to
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ensure scientific objectives are met. In
this case, icebreaking could result in
Level B harassment.
Below are descriptions of the
platforms and equipment that would be
deployed at different times during the
proposed activity.
Research Vessels
The R/V Sikuliaq would perform the
research cruise in September 2024 and
conduct testing of acoustic sources
during the cruise, as well as leave
sources behind to operate as a yearround navigation system observation.
The vessel to be used in a potential 2025
cruise is yet to be determined but the
most probable option would be the CGC
HEALY.
The R/V Sikuliaq has a maximum
speed of approximately 12 knots (22.2
km per hour (km/hr)) with a cruising
speed of 11 knots (20.4 km/hr). The R/
V Sikuliaq is not an icebreaking ship but
an ice strengthened ship. It would not
be icebreaking and therefore acoustic
signatures of icebreaking for the R/V
Sikuliaq are not relevant. CGC HEALY
travels at a maximum speed of 17 knots
(31.5 km/hr) with a cruising speed of 12
knots (22.2 km/hr) and a maximum
speed of 3 knots (5.6 km/hr) when
traveling through 1.07 m (3.5 ft) of sea
ice. While no icebreaking cruise on the
CGC HEALY is scheduled during the
IHA period, need may arise. Therefore,
for the purposes of this IHA application,
an icebreaking cruise is considered.
The R/V Sikuliaq, CGC HEALY, or
any other vessel operating a research
cruise associated with the Proposed
Action may perform the following
activities during their research cruises:
• Deployment of moored and/or icetethered passive sensors (oceanographic
measurement devices, acoustic
receivers);
• Deployment of moored and/or icetethered active acoustic sources to
transmit acoustic signals;
• Deployment of UUVs;
• Deployment of drifting buoys, with
or without acoustic sources; or,
• Recovery of equipment.
Glider Surveys
Glider surveys are proposed for the
research cruise. All gliders would be
recovered; some may be recovered
during the cruise, but the remainder
would be recovered at a later date. Up
to four gliders would be deployed
during the research cruise as part of onice operations (one to two gliders would
be associated with each on-ice station).
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Long-endurance, autonomous sea
gliders are intended for use in extended
missions in ice-covered waters. Gliders
are buoyancy-driven, equipped with
satellite modems providing two-way
communication, and are capable of
transiting to depths of up to 1,000 m
(3,280 ft). Gliders would collect data in
the area of the shallow water sources
and moored sources, moving at a speed
of 0.25 meters per second (m/s; 23
kilometers per day (km/day)). A
combination of recent advances in sea
glider technology would provide fullyear endurance. When operating in icecovered waters, gliders navigate by
trilateration (the process of determining
location by measurement of distances,
using the geometry of circles, spheres or
triangles) from moored acoustic sound
sources (or dead reckoning should
navigation signals be unavailable); they
do not contain any active acoustic
sources. Hibernating gliders would
continue to track their position, waking
to reposition should they drift too far
from their target region. Gliders would
measure temperature, salinity, dissolved
oxygen, rates of dissipation of
temperature variance (and vertical
turbulent diffusivity), and multi-spectral
down welling irradiance.
Moored and Drifting Acoustic Sources
During the September 2024 cruise,
active acoustic sources would be
lowered from the cruise vessel while
stationary, deployed on gliders and
UUVs, or deployed on fixed AMOS and
VLF moorings for intermittent testing of
the system components. The testing
would take place in the vicinity of the
source locations in figure 1. During this
testing, 35 Hz, 900 Hz, 10 kHz, and
acoustic modems would be employed.
No UUV use is planned during the
September 2024 research cruise but
UUV use may be included in future test
plans covered by this IHA.
Up to four fixed acoustic navigation
sources transmitting at 900 Hz would
remain in place for a year. These
moorings would be anchored on the
seabed and held in the water column
with subsurface buoys. All sources
would be deployed by shipboard
winches, which would lower sources
and receivers in a controlled manner.
Anchors would be steel ‘‘wagon
wheels’’ typically used for this type of
deployment. Two VLF sources
transmitting at 35 Hz would be
deployed in a similar manner. Two
drifting IGBs would also be configured
with active acoustic sources.
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TABLE 1—CHARACTERISTICS OF MODELED ACOUSTIC SOURCES
Platform
(total number deployed)
Acoustic source
REMUS 600 UUV a (up
to 1).
REMUS 600 UUV a (up
to 1).
WHOI Micro-modem ....
IGB (drifting) (2) ............
WHOI Micro-modem ....
IGB (drifting) (2) ............
WHOI Micro-modem ....
Mooring (6) ...................
WHOI Micro-modem
(4).
VLF (2) .........................
Mooring (6) ...................
Purpose/
function
UUV/WHOI Micromodem.
Signal strength
(dB re 1 μPa at 1 m)
Pulse width/duty cycle
NTE 180 dB by sys design limits.
NTE 185 dB by sys design limits.
5 pings/hour with 30
sec pulse length.
10% average duty
cycle, with 4 sec
pulse length.
Transmit every 4 hours,
30 sec pulse length.
Typically receive only.
Transmit is very
intermittent.
Transmit every 4 hours,
30 sec pulse length.
Up to 4 times per day,
10 minutes each.
Frequency
Acoustic communications.
Acoustic communications.
900–950 Hz
Acoustic communications.
Acoustic communications.
900–950 Hz
Acoustic Navigation .....
900–950 Hz
Acoustic Navigation .....
35 Hz ...........
8–14 kHz ......
8–14 kHz ......
NTE 180 dB by sys design limits.
NTE 185 dB by sys design limits.
NTE 180 dB by sys design limits.
NTE 190 dB .................
Note: dB re 1 μPa at 1 m = decibels referenced to 1 microPascal at 1 meter; Hz = Hertz; IGB = Ice Gateway Buoy; kHz = kilohertz; NTE = not
to exceed; VLF = very low frequency; WHOI = Woods Hole Oceanographic Institution.
a REMUS use is not anticipated during the September 2024 cruise but is included in case of future use during the proposed IHA period.
Activities Not Likely To Result in Take
The following activities have been
determined to be unlikely to result in
take of marine mammals. These
activities are described here but they are
not discussed further in this notice.
De minimis Sources—The ONR
characterizes de minimis sources as
those with the following parameters:
low source levels (SLs), narrow beams,
downward directed transmission, short
pulse lengths, frequencies outside
known marine mammal hearing ranges,
or some combination of these factors
(Navy, 2013). NMFS concurs with the
ONR’s determination that the sources
they have identified here as de minimis
are unlikely to result in take of marine
mammals. The following are some of the
planned de minimis sources which
would be used during the proposed
action: Woods Hole Oceanographic
Institution (WHOI) micromodem,
Acoustic Doppler Current Profilers
(ADCPs), ice profilers, and additional
sources below 160 decibels referenced
to 1 microPascal (dB re 1 mPa) used
during towing operations. ADCPs may
be used on moorings. Ice-profilers
measure ice properties and roughness.
The ADCPs and ice-profilers would all
be above 200 kHz and therefore out of
marine mammal hearing ranges, with
the exception of the 75 kHz ADCP
which has the characteristics and de
minimis justification listed in table 2.
They may be employed on moorings or
UUVs.
A WHOI micromodem will also be
employed during the leave behind
period. In contrast with the WHOI
micromodem usage described in table 1,
which covers the use of the
micromodem during research cruises,
the use of the source during the leave
behind period differs in nature. During
this period, it is being used for very
intermittent communication with
vehicles to communicate vehicle status
for safety of navigation purposes, and is
treated as de minimis while employed
in this manner.
TABLE 2—PARAMETERS FOR DE MINIMIS NON-IMPULSIVE ACOUSTIC SOURCES
Sound pressure level
(dB re 1 μPa
at 1 m)
Frequency
range
(kHz)
Source name
ADCP ................................................
Nortek Signature 500 kHz Doppler
Velocity Log.
CTD Attached Echosounder .............
Pulse length
(seconds)
Duty cycle
(percent)
De minimis justification
>200, 150, or
75
500
190
<0.001
<0.1
214
<0.1
<13
5–20
160
0.004
2
Very low pulse length, narrow
beam, moderate source level.
Very high frequency.
Very low source level.
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Note: dB re 1 μPa at 1 m = decibels referenced to 1 microPascal at 1 meter; kHz = kilohertz; ADCP = acoustic Doppler current profiler; CTD =
conductivity temperature depth.
Drifting Oceanographic Sensors—
Observations of ocean-ice interactions
require the use of sensors that are
moored and embedded in the ice. For
the proposed action, it will not be
required to break ice to do this, as
deployments can be performed in areas
of low ice-coverage or free floating ice.
Sensors are deployed within a few
dozen meters of each other on the same
ice floe. Three types of sensors would be
used: autonomous ocean flux buoys,
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Integrated Autonomous Drifters, and
ice-tethered profilers. The autonomous
ocean flux buoys measure
oceanographic properties just below the
ocean-ice interface. The autonomous
ocean flux buoys would have ADCPs
and temperature chains attached, to
measure temperature, salinity, and other
ocean parameters the top 6 m (20 ft) of
the water column. Integrated
Autonomous Drifters would have a long
temperate string extending down to 200
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m (656 ft) depth and would incorporate
meteorological sensors, and a
temperature spring to estimate ice
thickness. The ice-tethered profilers
would collect information on ocean
temperature, salinity, and velocity down
to 250 m (820 ft) depth.
Up to 20 Argo-type autonomous
profiling floats may be deployed in the
central Beaufort Sea. Argo float drift at
1,500 m (4,921 ft) depth, profiling from
2,000 m (6,562 ft) to the sea surface once
every 10 days to collect profiles of
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temperature and salinity. Moored
Oceanographic Sensors—Moored
sensors would capture a range of ice,
ocean, and atmospheric conditions on a
year-round basis. These would be
bottom anchored, sub-surface moorings
measuring velocity, temperature, and
salinity in the upper 500 m (1,640 ft) of
the water column. The moorings also
collect high-resolution acoustic
measurements of the ice using the ice
profilers described above. Ice velocity
and surface waves would be measured
by 500 kHz multibeam sonars from
Nortek Signatures. The moored
oceanographic sensors described above
use only de minimis sources and are
therefore not anticipated to have the
potential for impacts on marine
mammals or their habitat. On-ice
Measurements—On-ice measurement
systems would be used to collect
weather data. These would include an
Autonomous Weather Station and an Ice
Mass Balance Buoy. The Autonomous
Weather Station would be deployed on
a tripod; the tripod has insulated foot
platforms that are frozen into the ice.
The system would consist of an
anemometer, humidity sensor, and
pressure sensor. The Autonomous
Weather Station also includes an
altimeter that is de minimis due to its
very high frequency (200 kHz). The Ice
Mass Balance Buoy is a 6 m (20 ft)
sensor string, which is deployed
through a 5 centimeter (cm; 2 inch (in))
hole drilled into the ice. The string is
weighted by a 1 kilogram (kg; 2.2 pound
(lb)) lead weight and is supported by a
tripod. The buoy contains a de minimis
200 kHz altimeter and snow depth
sensor. Autonomous Weather Stations
and Ice Mass Balance Buoys will be
deployed and will drift with the ice,
making measurements until their host
ice floes melt, thus destroying the
instruments (likely in summer, roughly
1 year after deployment). After the onice instruments are destroyed they
cannot be recovered and would sink to
the seafloor as their host ice floes
melted.
Proposed mitigation, monitoring, and
reporting measures are described in
detail later in this document (please see
Proposed Mitigation and Proposed
Monitoring and Reporting).
Description of Marine Mammals in the
Area of Specified Activities
Sections 3 and 4 of the application
summarize available information
regarding status and trends, distribution
and habitat preferences, and behavior
and life history of the potentially
affected species. NMFS fully considered
all of this information, and we refer the
reader to these descriptions, instead of
reprinting the information. Additional
information regarding population trends
and threats may be found in NMFS’
Stock Assessment Reports (SARs;
https://www.fisheries.noaa.gov/
national/marine-mammal-protection/
marine-mammal-stock-assessments)
and more general information about
these species (e.g., physical and
behavioral descriptions) may be found
on NMFS’ website (https://
www.fisheries.noaa.gov/find-species).
Table 3 lists all species or stocks for
which take is expected and proposed to
be authorized for this activity and
summarizes information related to the
population or stock, including
regulatory status under the MMPA and
Endangered Species Act (ESA) and
potential biological removal (PBR),
where known. PBR is defined by the
MMPA as the maximum number of
animals, not including natural
mortalities, that may be removed from a
marine mammal stock while allowing
that stock to reach or maintain its
optimum sustainable population (as
described in NMFS’ SARs). While no
serious injury or mortality is anticipated
or proposed to be authorized here, PBR
and annual serious injury and mortality
from anthropogenic sources are
included here as gross indicators of the
status of the species or stocks and other
threats.
Marine mammal abundance estimates
presented in this document represent
the total number of individuals that
make up a given stock or the total
number estimated within a particular
study or survey area. NMFS’ stock
abundance estimates for most species
represent the total estimate of
individuals within the geographic area,
if known, that comprises that stock. For
some species, this geographic area may
extend beyond U.S. waters. All managed
stocks in this region are assessed in
NMFS’ U.S. Alaska SARs (Young et al.,
2023). All values presented in table 3
are the most recent available at the time
of publication and are available online
at: https://www.fisheries.noaa.gov/
national/marine-mammal-protection/
marine-mammal-stock-assessments.
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TABLE 3—SPECIES LIKELY IMPACTED BY THE SPECIFIED ACTIVITIES 1
ESA/
MMPA
status;
strategic
(Y/N) 2
Common name
Scientific name
Stock
Beluga Whale ..........................
Beluga Whale ..........................
Ringed Seal .............................
Delphinapterus leucas ............
Delphinapterus leucas ............
Pusa hispida ...........................
Beaufort Sea ..........................
Eastern Chukchi .....................
Arctic ......................................
-, -, N
-, -, N
T, D, Y
Stock
abundance (CV, Nmin,
most recent
abundance
survey) 3
39,258 (0.229, N/A, 1992) .....
13,305 (0.51, 8,875, 2017) ....
UND 5 (UND, UND, 2013) ......
PBR
UND
178
UND
Annual
M/SI 4
104
56
6,459
1 Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy’s Committee on Taxonomy
(https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/).
2 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 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.
3 NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessmentreports-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
4 These values, found in NMFS’s SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial fisheries, vessel strike). Annual 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.
5 A reliable population estimate for the entire stock is not available. Using a sub-sample of data collected from the U.S. portion of the Bering Sea, an abundance estimate of 171,418 ringed seals has been calculated, but this estimate does not account for availability bias due to seals in the water or in the shore-fast ice zone at
the time of the survey. The actual number of ringed seals in the U.S. portion of the Bering Sea is likely much higher. Using the Nmin based upon this negatively biased population estimate, the PBR is calculated to be 4,755 seals, although this is also a negatively biased estimate.
As indicated above, both species
(with three managed stocks) in table 3
temporally and spatially co-occur with
the activity to the degree that take is
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reasonably likely to occur. While
bowhead whales (Balaena mysticetus),
gray whales (Eschrichtius robustus),
bearded seals (Erignathus barbatus),
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spotted seals (Phoca largha), and ribbon
seals (Histriophoca fasciata) have been
documented in the area, the temporal
and/or spatial occurrence of these
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species is such that take is not expected
to occur, and they are not discussed
further beyond the explanation
provided below.
Due to the location of the study area
(i.e., northern offshore, deep water),
there were no calculated exposures for
the bowhead whale, gray whale,
bearded seal, spotted seal, and ribbon
seal from quantitative modeling of
acoustic sources. Bowhead and gray
whales are closely associated with the
shallow waters of the continental shelf
in the Beaufort Sea and are unlikely to
be exposed to acoustic harassment from
this activity (Young et al., 2023). Gray
whales feed primarily in the Beaufort
Sea, Chukchi Sea, and Northwestern
Bering Sea during the summer and fall,
but migrate south to winter in Baja
California lagoons (Young et al., 2023).
Gray whales are primarily bottom
feeders (Swartz et al., 2006) in water
depths of less than 60 m (196.9 ft) (Pike,
1962). Therefore, on the rare occasion
that a gray whale does overwinter in the
Beaufort Sea (Stafford et al., 2007), we
would expect an overwintering
individual to remain in shallow water
over the continental shelf where it could
feed. Spotted seals tend to prefer pack
ice areas with water depths less than
200 m (656.2 ft) during the spring and
move to coastal habitats in the summer
and fall, found as far north as 69–72
degrees N (Muto et al., 2021). Although
the study area includes some waters
south of 72 degrees N, the acoustic
sources with the potential to result in
take of marine mammals are not found
below that latitude and spotted seals are
not expected to be exposed. Ribbon
seals are found year-round in the Bering
Sea but may seasonally range into the
Chukchi Sea (Muto et al., 2021). The
proposed action occurs primarily in the
Beaufort Sea, outside of the core range
of ribbon seals, thus ribbon seals are not
expected to be behaviorally harassed.
Narwhals (Monodon monoceros) are
considered extralimital in the project
area and are not expected to be
encountered. As no harassment is
expected of the bowhead whale, gray
whale, spotted seal, bearded seal, ribbon
seal, and narwhal, these species will not
be discussed further in this proposed
notice.
The ONR utilized Conn et al. (2014)
in their IHA application as an
abundance estimate for ringed seals,
which is based upon aerial abundance
and distribution surveys conducted in
the U.S. portion Bering Sea in 2012
(171,418 ringed seals) (Muto et al.,
2021). This value is likely an
underestimate due to the lack of
accounting for availability bias for seals
that were in the water at the time of the
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surveys as well as not including seals
located within the shore-fast ice zone
(Muto et al., 2021). Muto et al. (2021)
notes that an accurate population
estimate is likely larger by a factor of
two or more. However, no accepted
population estimate is present for Arctic
ringed seals. Therefore, NMFS will also
adopt the Conn et al. (2014) abundance
estimate (171,418) for further analyses
and discussions on this proposed action
by ONR.
In addition, the polar bear (Ursus
maritimus) and Pacific walrus
(Odobenus rosmarus) may be found
both on sea ice and/or in the water
within the Beaufort Sea and Chukchi
Sea. These species are managed by the
U.S. Fish and Wildlife Service rather
than NMFS and, therefore, they are not
considered further in this document.
Beluga Whale
Beluga whales are distributed
throughout seasonally ice-covered arctic
and subarctic waters of the Northern
Hemisphere (Gurevich, 1980), and are
closely associated with open leads and
polynyas in ice-covered regions
(Hazard, 1988). Belugas may be either
migratory or residential (non-migratory),
depending on the population. Seasonal
distribution is affected by ice cover,
tidal conditions, access to prey,
temperature, and human interaction
(Frost et al., 1985; Hauser et al., 2014).
There are five beluga whale stocks
recognized within U.S. waters: Cook
Inlet, Bristol Bay, eastern Bering Sea,
eastern Chukchi Sea, and Beaufort Sea.
Two stocks, the Beaufort Sea and
eastern Chukchi Sea stocks, have the
potential to occur in the location of this
proposed action.
Migratory Biologically Important
Areas (BIAs) for belugas in the eastern
Chukchi and Alaskan Beaufort Sea
overlap the southern and western
portion of the Study Area (Clarke et al.,
2023). A migration corridor for both
stocks of beluga whale includes the
eastern Chukchi Sea through the
Beaufort Sea, with the Beaufort Sea
stock utilizing the migratory BIA in
April-May and the Eastern Chukchi Sea
stock utilizing portions of the area in
November. There are also feeding BIAs
for both stocks throughout the Arctic
region (Clarke et al., 2023). During the
winter, they can be found foraging in
offshore waters associated with pack
ice. When the sea ice melts in summer,
they move to warmer river estuaries and
coastal areas for molting and calving
(Muto et al., 2021). Annual migrations
can span over thousands of kilometers.
The residential Beaufort Sea
populations participate in short distance
movements within their range
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throughout the year. Based on satellite
tags (Suydam et al., 2001; Hauser et al.,
2014), there is some overlap in
distribution with the eastern Chukchi
Sea beluga whale stock.
During the winter, eastern Chukchi
Sea belugas occur in offshore waters
associated with pack ice. In the spring,
they migrate to warmer coastal
estuaries, bays, and rivers where they
may molt (Finley, 1982; Suydam, 2009),
give birth to, and care for their calves
(Sergeant and Brodie, 1969). Eastern
Chukchi Sea belugas move into coastal
areas, including Kasegaluk Lagoon
(outside of the proposed project site), in
late June and animals are sighted in the
area until about mid-July (Frost and
Lowry, 1990; Frost et al., 1993). Satellite
tags attached to eastern Chukchi Sea
belugas captured in Kasegaluk Lagoon
during the summer showed these
whales traveled 1,100 km (593 nm)
north of the Alaska coastline, into the
Canadian Beaufort Sea within three
months (Suydam et al., 2001). Satellite
telemetry data from 23 whales tagged
during 1998–2007 suggest variation in
movement patterns for different age
and/or sex classes during JulySeptember (Suydam et al., 2005). Adult
males used deeper waters and remained
there for the duration of the summer; all
belugas that moved into the Arctic
Ocean (north of 75 degrees N) were
males, and males traveled through 90
percent pack ice cover to reach deeper
waters in the Beaufort Sea and Arctic
Ocean (79–80 degrees N) by late July/
early August. Adult and immature
female belugas remained at or near the
shelf break in the south through the
eastern Bering Strait into the northern
Bering Sea, remaining north of Saint
Lawrence Island over the winter.
Ringed Seal
Ringed seals are the most common
pinniped in the Study Area and have
wide distribution in seasonally and
permanently ice-covered waters of the
Northern Hemisphere (North Atlantic
Marine Mammal Commission, 2004).
Throughout their range, ringed seals
have an affinity for ice-covered waters
and are well adapted to occupying both
shore-fast and pack ice (Kelly, 1988).
Ringed seals can be found further
offshore than other pinnipeds since they
can maintain breathing holes in ice
thickness greater than 2 m (6.6 ft)
(Smith and Stirling, 1975). The
breathing holes are maintained by
ringed seals using their sharp teeth and
claws found on their fore flippers. They
remain in contact with ice most of the
year and use it as a platform for molting
in late spring to early summer, for
pupping and nursing in late winter to
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early spring, and for resting at other
times of the year (Muto et al., 2018).
Ringed seals have at least two distinct
types of subnivean lairs: Haulout lairs
and birthing lairs (Smith and Stirling,
1975). Haul-out lairs are typically
single-chambered and offer protection
from predators and cold weather.
Birthing lairs are larger, multichambered areas that are used for
pupping in addition to protection from
predators. Ringed seals pup on both
shore-fast ice as well as stable pack ice.
Lentfer (1972) found that ringed seals
north of Utqiaġvik, Alaska, build their
subnivean lairs on the pack ice near
pressure ridges. Since subnivean lairs
were found north of Utqiaġvik, Alaska,
in pack ice, they are also assumed to be
found within the sea ice in the proposed
project site. Ringed seals excavate
subnivean lairs in drifts over their
breathing holes in the ice, in which they
rest, give birth, and nurse their pups for
5–9 weeks during late winter and spring
(Chapskii, 1940; McLaren, 1958; Smith
and Stirling, 1975). Ringed seals are
born beginning in March but the
majority of births occur in early April.
About a month after parturition, mating
begins in late April and early May.
In Alaskan waters, during winter and
early spring when sea ice is at its
maximum extent, ringed seals are
abundant in the northern Bering Sea,
Norton and Kotzebue Sounds, and
throughout the Chukchi and Beaufort
seas (Frost, 1985; Kelly, 1988). Passive
acoustic monitoring of ringed seals from
a high frequency recording package
deployed at a depth of 240 m (787 ft) in
the Chukchi Sea 120 km (65 nm) northnorthwest of Utqiaġvik, Alaska detected
ringed seals in the area between midDecember and late May over the 4 year
study (Jones et al., 2014). In addition,
ringed seals have been observed near
and beyond the outer boundary of the
U.S. EEZ (Beland and Ireland, 2010).
During the spring and early summer,
ringed seals may migrate north as the
ice edge recedes and spend their
summers in the open water period of the
northern Beaufort and Chukchi Seas
(Frost, 1985). Foraging-type movements
have been recorded over the continental
shelf and north of the continental shelf
waters (Von Duyke et al., 2020). During
this time, sub-adult ringed seals may
also occur in the Arctic Ocean Basin
(Hamilton et al., 2015; Hamilton et al.,
2017).
With the onset of fall freeze, ringed
seal movements become increasingly
restricted and seals will either move
west and south with the advancing ice
pack with many seals dispersing
throughout the Chukchi and Bering
Seas, or remaining in the Beaufort Sea
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(Crawford et al., 2012; Frost and Lowry,
1984; Harwood et al., 2012). Kelly et al.
(2010a) tracked home ranges for ringed
seals in the subnivean period (using
shore-fast ice); the size of the home
ranges varied from less than 1 up to 279
km2 (median = 0.62 km2 for adult males,
0.65 km2 for adult females). Most (94
percent) of the home ranges were less
than 3 km2 during the subnivean period
(Kelly et al., 2010a). Near large
polynyas, ringed seals maintain ranges,
up to 7,000 km2 during winter and
2,100 km2 during spring (Born et al.,
2004). Some adult ringed seals return to
the same small home ranges they
occupied during the previous winter
(Kelly et al., 2010a). The size of winter
home ranges can vary by up to a factor
of 10 depending on the amount of fast
ice; seal movements were more
restricted during winters with extensive
fast ice, and were much less restricted
where fast ice did not form at high
levels (Harwood et al., 2015).
Of the five recognized subspecies of
ringed seals, the Arctic ringed seal
occurs in the Arctic Ocean and Bering
Sea and is the only stock that occurs in
U.S. waters. NMFS listed the Arctic
ringed seal subspecies as threatened
under the ESA on December 28, 2012
(77 FR 76706), primarily due to
anticipated loss of sea ice through the
end of the 21st century. Climate change
presents a major concern for the
conservation of ringed seals due to the
potential for long-term habitat loss and
modification (Muto et al., 2021). Based
upon an analysis of various life history
features and the rapid changes that may
occur in ringed seal habitat, ringed seals
are expected to be highly sensitive to
climate change (Laidre et al., 2008;
Kelly et al., 2010b).
Critical Habitat
Critical habitat for the ringed seal was
designated in May 2022 and includes
marine waters within one specific area
in the Bering, Chukchi, and Beaufort
Seas (87 FR 19232, April 1, 2022).
Essential features established by NMFS
for conservation of ringed seals are (1)
snow-covered sea ice habitat suitable for
the formation and maintenance of
subnivean birth lairs used for sheltering
pups during whelping and nursing,
which is defined as waters 3 m (9.8 ft)
or more in depth (relative to Mean
Lower Low Water (MLLW)) containing
areas of seasonal land-fast (shore-fast)
ice or dense, stable pack ice, that have
undergone deformation and contain
snowdrifts of sufficient depth to form
and maintain birth lairs (typically at
least 54 cm (21.3 in) deep); (2) sea ice
habitat suitable as a platform for basking
and molting, which is defined as areas
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containing sea ice of 15 percent or more
concentration in waters 3 m (9.8 ft) or
more in depth (relative to MLLW); and
(3) primary prey resources to support
Arctic ringed seals, which are defined to
be small, often schooling, fishes, in
particular Arctic cod (Boreogadus
saida), saffron cod (Eleginus gracilis),
and rainbow smelt (Osmerus dentex);
and small crustaceans, in particular,
shrimps and amphipods.
The Study Area does not overlap with
ringed seal critical habitat (87 FR 19232,
April 1, 2022). However, as stated in
NMFS’ final rule for the Designation of
Critical Habitat for the Arctic
Subspecies of the Ringed Seal (87 FR
19232, April 1, 2022), the area excluded
from the critical habitat contains one or
more of the essential features of the
Arctic ringed seal’s critical habitat,
therefore, even though this area is
excluded from critical habitat
designation, habitat with the physical
and biological features essential for
ringed seal conservation is still available
to the species, although data are limited
to inform NMFS’ assessment of the
relative value of this area to the
conservation of the species. As
described later and in more detail in the
Potential Effects of Specified Activities
on Marine Mammals and Their Habitat
section, we expect minimal impacts to
marine mammal habitat as a result of
the ONR’s ARA, including impacts to
ringed seal sea ice habitat suitable as a
platform for basking and molting and
impacts on prey availability.
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. 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) and Southall et al. (2019)
recommended that marine mammals be
divided into hearing groups based on
directly measured (behavioral or
auditory evoked potential techniques) or
estimated hearing ranges (behavioral
response data, anatomical modeling,
etc.). 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-
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frequency cetaceans where the lower
bound was deemed to be biologically
implausible and the lower bound from
Southall et al. (2007) retained. Marine
mammal hearing groups and their
associated hearing ranges are provided
in table 4.
TABLE 4—MARINE MAMMAL HEARING
GROUPS
[NMFS, 2018]
Hearing group
Low-frequency (LF)
cetaceans (baleen
whales).
Mid-frequency (MF)
cetaceans (dolphins, toothed
whales, beaked
whales, bottlenose
whales).
High-frequency (HF)
cetaceans (true
porpoises, Kogia,
river dolphins,
Cephalorhynchid,
Lagenorhynchus
cruciger & L.
australis).
Phocid pinnipeds
(PW) (underwater)
(true seals).
Otariid pinnipeds
(OW) (underwater)
(sea lions and fur
seals).
Generalized
hearing range *
7 Hz to 35 kHz.
150 Hz to 160 kHz.
275 Hz to 160 kHz.
50 Hz to 86 kHz.
60 Hz to 39 kHz.
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* Represents the generalized hearing range
for the entire group as a composite (i.e., all
species within the group), where individual
species’ hearing ranges are typically not as
broad. Generalized hearing range chosen
based on approximately 65 dB threshold from
normalized composite audiogram, with the exception for lower limits for LF cetaceans
(Southall et al., 2007) and PW pinniped
(approximation).
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
(Hemilä et al., 2006; Kastelein et al.,
2009; Reichmuth et al., 2013). This
division between phocid and otariid
pinnipeds is now reflected in the
updated hearing groups proposed in
Southall et al. (2019).
For more detail concerning these
groups and associated frequency ranges,
please see NMFS (2018) for a review of
available information.
Potential Effects of Specified Activities
on Marine Mammals and Their Habitat
This section provides a discussion of
the ways in which components of the
specified activity may impact marine
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mammals and their habitat. The
Estimated Take of Marine Mammals
section later in this document includes
a quantitative analysis of the number of
individuals that are expected to be taken
by this activity. The Negligible Impact
Analysis and Determination section
considers the content of this section, the
Estimated Take of Marine Mammals
section, and the Proposed Mitigation
section, to draw conclusions regarding
the likely impacts of these activities on
the reproductive success or survivorship
of individuals and whether those
impacts are reasonably expected to, or
reasonably likely to, adversely affect the
species or stock through effects on
annual rates of recruitment or survival.
Description of Sound Sources
The marine soundscape is comprised
of both ambient and anthropogenic
sounds. Ambient sound is defined as
the all-encompassing sound in a given
place and is usually a composite of
sound from many sources both near and
far (ANSI, 1995). The sound level of an
area is defined by the total acoustical
energy being generated by known and
unknown sources. These sources may
include physical (e.g., waves, wind,
precipitation, earthquakes, ice,
atmospheric sound), biological (e.g.,
sounds produced by marine mammals,
fish, and invertebrates), and
anthropogenic sound (e.g., vessels,
dredging, aircraft, construction).
The sum of the various natural and
anthropogenic sound sources at any
given location and time—which
comprise ‘‘ambient’’ or ‘‘background’’
sound—depends not only on the source
levels (as determined by current
weather conditions and levels of
biological and shipping activity) but
also on the ability of sound to propagate
through the environment. In turn, sound
propagation is dependent on the
spatially and temporally varying
properties of the water column and sea
floor, and is frequency-dependent. As a
result of the dependence on a large
number of varying factors, ambient
sound levels can be expected to vary
widely over both coarse and fine spatial
and temporal scales. Sound levels at a
given frequency and location can vary
by 10–20 dB from day to day
(Richardson et al., 1995). The result is
that, depending on the source type and
its intensity, sound from the specified
activities may be a negligible addition to
the local environment or could form a
distinctive signal that may affect marine
mammals.
Active acoustic sources and
icebreaking, if necessary, are proposed
for use in the Study Area. The sounds
produced by these activities fall into
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one of two general sound types:
impulsive and non-impulsive.
Impulsive sounds (e.g., ice explosions,
gunshots, sonic booms, impact pile
driving) are typically transient, brief
(less than 1 second), broadband, and
consist of high peak sound pressure
with rapid rise time and rapid decay
(ANSI, 1986; NIOSH, 1998; NMFS,
2018). Non-impulsive sounds (e.g.,
aircraft, machinery operations such as
drilling or dredging, vibratory pile
driving, pile cutting, diamond wire
sawing, and active sonar systems) can
be broadband, narrowband, or tonal,
brief or prolonged (continuous or
intermittent), and typically do not have
the high peak sound pressure with raid
rise/decay time that impulsive sounds
do (ANSI, 1986; NIOSH, 1998; NMFS,
2018). The distinction between these
two sound types is important because
they have differing potential to cause
physical effects, particularly with regard
to hearing (e.g., Ward, 1997; Southall et
al., 2007).
The likely or possible impacts of the
ONR’s proposed action on marine
mammals involve both non-acoustic and
acoustic stressors. Potential nonacoustic stressors could result from the
physical presence of vessels, equipment,
and personnel (e.g., icebreaking
impacts, vessel and in-water vehicle
strike, and bottom disturbance);
however, any impacts to marine
mammals are expected to primarily be
acoustic in nature (e.g., non-impulsive
acoustic sources, noise from icebreaking
vessel (‘‘icebreaking noise’’), and vessel
noise).
Acoustic Impacts
The introduction of anthropogenic
noise into the aquatic environment from
active acoustic sources and noise from
icebreaking is the means by which
marine mammals may be harassed from
the ONR’s specified activity. In general,
animals exposed to natural or
anthropogenic sound may experience
behavioral, physiological, and/or
physical effects, ranging in magnitude
from none to severe (Southall et al.,
2007). In general, exposure to pile
driving noise has the potential to result
in behavioral reactions (e.g., avoidance,
temporary cessation of foraging and
vocalizing, changes in dive behavior)
and, in limited cases, an auditory
threshold shift (TS). Exposure to
anthropogenic noise can also lead to
non-observable physiological responses
such an increase in stress hormones.
Additional noise in a marine mammal’s
habitat can mask acoustic cues used by
marine mammals to carry out daily
functions such as communication and
predator and prey detection. The effects
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of pile driving noise on marine
mammals are dependent on several
factors, including, but not limited to,
sound type (e.g., impulsive versus nonimpulsive), the species, age and sex
class (e.g., adult male versus mother
with calf), duration of exposure, the
distance between the pile and the
animal, received levels, behavior at time
of exposure, and previous history with
exposure (Wartzok et al., 2004; Southall
et al., 2007). Here we discuss physical
auditory effects (i.e., TS) followed by
behavioral effects and potential impacts
on habitat.
NMFS defines a noise-induced TS as
a change, usually an increase, in the
threshold of audibility at a specified
frequency or portion of an individual’s
hearing range above a previously
established reference level (NMFS,
2018). The amount of TS is customarily
expressed in dB and TS can be
permanent or temporary. As described
in NMFS (2018), there are numerous
factors to consider when examining the
consequence of TS, including, but not
limited to, the signal temporal pattern
(e.g., impulsive or non-impulsive),
likelihood an individual would be
exposed for a long enough duration or
to a high enough level to induce a TS,
the magnitude of the TS, time to
recovery (seconds to minutes or hours to
days), the frequency range of the
exposure (i.e., spectral content), the
hearing and vocalization frequency
range of the exposed species relative to
the signal’s frequency spectrum (i.e.,
how animal uses sound within the
frequency band of the signal) (Kastelein
et al., 2014), and the overlap between
the animal and the source (e.g., spatial,
temporal, and spectral).
Permanent Threshold Shift (PTS)—
NMFS defines PTS as a permanent,
irreversible increase in the threshold of
audibility at a specified frequency or
portion of an individual’s hearing range
above a previously established reference
level (NMFS, 2018). Available data from
humans and other terrestrial mammals
indicate that a 40 dB TS approximates
PTS onset (see Ward et al., 1958; Ward
et al., 1959; Ward, 1960; Kryter et al.,
1966; Miller, 1974; Ahroon et al., 1996;
Henderson et al., 2008). PTS levels for
marine mammals are estimates as, with
the exception of a single study
unintentionally inducing PTS in a
harbor seal (e.g., Kastak et al., 2008),
there are no empirical data measuring
PTS in marine mammals largely due to
the fact that, for various ethical reasons,
experiments involving anthropogenic
noise exposure at levels inducing PTS
are not typically pursued or authorized
(NMFS, 2018).
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Temporary Threshold Shift (TTS)—
TTS is a temporary, reversible increase
in the threshold of audibility at a
specified frequency or portion of an
individual’s hearing range above a
previously established reference level
(NMFS, 2018). Based on data from
cetacean TTS measurements (see
Southall et al., 2007), a TTS of 6 dB is
considered the minimum TS clearly
larger than any day-to-day or session-tosession variation in a subject’s normal
hearing ability (Finneran et al., 2000;
Schlundt et al., 2000; Finneran et al.,
2002). As described in Finneran (2016),
marine mammal studies have shown the
amount of TTS increases with
cumulative sound exposure level
(SELcum) in an accelerating fashion: At
low exposures with lower SELcum, the
amount of TTS is typically small and
the growth curves have shallow slopes.
At exposures with higher SELcum, the
growth curves become steeper and
approach linear relationships with the
noise SEL.
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
the Auditory Masking section). For
example, a marine mammal may be able
to readily compensate for a brief,
relatively small amount of TTS in a noncritical frequency range that takes place
during a time when the animal is
traveling through the open ocean, 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
time when communication is critical for
successful mother/calf interactions
could have more serious impacts. We
note that 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
cost.
Many studies have examined noiseinduced hearing loss in marine
mammals (see Finneran, 2015; Southall
et al., 2019 for summaries). TTS is the
mildest form of hearing impairment that
can occur during exposure to sound
(Kryter et al., 1966). While experiencing
TTS, the hearing threshold rises, and a
sound must be at a higher level in order
to be heard. In terrestrial and marine
mammals, TTS can last from minutes or
hours to days (in cases of strong TTS).
In many cases, hearing sensitivity
recovers rapidly after exposure to the
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sound ends. For cetaceans, published
data on the onset of TTS are limited to
captive bottlenose dolphin (Tursiops
truncatus), beluga whale, harbor
porpoise (Phocoena phocoena), and
Yangtze finless porpoise (Neophocoena
asiaeorientalis) (Southall et al., 2019).
For pinnipeds in water, measurements
of TTS are limited to harbor seals
(Phoca vitulina), elephant seals
(Mirounga angustirostris), bearded seals,
and California sea lions (Zalophus
californianus) (Kastak et al., 1999;
Kastak et al., 2008; Kastelein et al.,
2020b; Reichmuth et al., 2013; Sills et
al., 2020). TTS was not observed in
spotted and ringed seals exposed to
single airgun impulse sounds at levels
matching previous predictions of TTS
onset (Reichmuth et al., 2016). These
studies examine hearing thresholds
measured in marine mammals before
and after exposure to intense or longduration sound exposure. The
difference between the pre-exposure
and post-exposure thresholds can be
used to determine the amount of
threshold shift at various post-exposure
times.
The amount and onset of TTS
depends on the exposure frequency.
Sounds at low frequencies, well below
the region of best sensitivity for a
species or hearing group, are less
hazardous than those at higher
frequencies, near the region of best
sensitivity (Finneran and Schlundt,
2013). At low frequencies, onset-TTS
exposure levels are higher compared to
those in the region of best sensitivity
(i.e., a low frequency noise would need
to be louder to cause TTS onset when
TTS exposure level is higher), as shown
for harbor porpoises and harbor seals
(Kastelein et al., 2019a; Kastelein et al.,
2019b; Kastelein et al., 2020a; Kastelein
et al., 2020b). Note that in general,
harbor seals and harbor porpoises have
a lower TTS onset than other measured
pinniped or cetacean species (Finneran,
2015). In addition, 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 (Mooney et al., 2009;
Finneran et al., 2010; Kastelein et al.,
2014; Kastelein et al., 2015). This means
that TTS predictions based on the total
SELcum will overestimate the amount of
TTS from intermittent exposures, such
as sonars and impulsive sources.
Nachtigall et al. (2018) describe
measurements of hearing sensitivity of
multiple odontocete species (bottlenose
dolphin, harbor porpoise, beluga whale,
and false killer whale (Pseudorca
crassidens)) when a relatively loud
sound was preceded by a warning
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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). Data available on
noise-induced hearing loss for
mysticetes are currently lacking (NMFS,
2018). Additionally, the existing marine
mammal TTS data come from a limited
number of individuals within these
species.
Relationships between TTS and PTS
thresholds have not been studied in
marine mammals and there is no PTS
data for cetaceans, but such
relationships are assumed to be similar
to those in humans and other terrestrial
mammals. PTS typically occurs at
exposure levels at least several decibels
above that inducing mild TTS (e.g., a
40-dB threshold shift approximates PTS
onset (Kryter et al., 1966; Miller, 1974),
while a 6-dB threshold shift
approximates TTS onset (Southall et al.,
2007; Southall et al., 2019). Based on
data from terrestrial mammals, a
precautionary assumption is that the
PTS thresholds for impulsive sounds
(such as impact pile driving pulses as
received close to the source) are at least
6 dB higher than the TTS threshold on
a peak-pressure basis and PTS
cumulative sound exposure level
thresholds are 15 to 20 dB higher than
TTS cumulative sound exposure level
thresholds (Southall et al., 2007;
Southall et al., 2019). Given the higher
level of sound or longer exposure
duration necessary to cause PTS as
compared with TTS, it is considerably
less likely that PTS could occur.
Activities for this project include
active acoustics, equipment deployment
and recovery, and, potentially,
icebreaking. For the proposed action,
these activities would not occur at the
same time and there would likely be
pauses in activities producing the sound
during each day. Given these pauses
and that many marine mammals are
likely moving through the Study Area
and not remaining for extended periods
of time, the potential for TS declines.
Behavioral Harassment—Exposure to
noise from pile driving and drilling also
has the potential to behaviorally disturb
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marine mammals. Generally speaking,
NMFS considers a behavioral
disturbance that rises to the level of
harassment under the MMPA a nonminor response—in other words, not
every response qualifies as behavioral
disturbance, and for responses that do,
those of a higher level, or accrued across
a longer duration, have the potential to
affect foraging, reproduction, or
survival. Behavioral disturbance may
include a variety of effects, including
subtle changes in behavior (e.g., minor
or brief avoidance of an area or changes
in vocalizations), more conspicuous
changes in similar behavioral activities,
and more sustained and/or potentially
severe reactions, such as displacement
from or abandonment of high-quality
habitat. Behavioral responses may
include changing durations of surfacing
and dives, changing direction and/or
speed; reducing/increasing vocal
activities; changing/cessation of certain
behavioral activities (such as socializing
or feeding); eliciting a visible startle
response or aggressive behavior (such as
tail/fin slapping or jaw clapping);
avoidance of areas where sound sources
are located. Pinnipeds may increase
their haul out time, possibly to avoid inwater disturbance (Thorson and Reyff,
2006). Behavioral responses to sound
are highly variable and context-specific
and any reactions depend on numerous
intrinsic and extrinsic factors (e.g.,
species, state of maturity, experience,
current activity, reproductive state,
auditory sensitivity, time of day), as
well as the interplay between factors
(e.g., Richardson et al., 1995; Wartzok et
al., 2004; Southall et al., 2007; Southall
et al., 2019; Weilgart, 2007; Archer et
al., 2010). Behavioral reactions can vary
not only among individuals but also
within an individual, depending on
previous experience with a sound
source, context, and numerous other
factors (Ellison et al., 2012), and can
vary depending on characteristics
associated with the sound source (e.g.,
whether it is moving or stationary,
number of sources, distance from the
source). In general, pinnipeds seem
more tolerant of, or at least habituate
more quickly to, potentially disturbing
underwater sound than do cetaceans,
and generally seem to be less responsive
to exposure to industrial sound than
most cetaceans. Please see Appendices
B and C of Southall et al. (2007) and
Gomez et al. (2016) for reviews of
studies involving marine mammal
behavioral responses to sound.
Habituation can occur when an
animal’s response to a stimulus wanes
with repeated exposure, usually in the
absence of unpleasant associated events
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(Wartzok et al., 2004). Animals are most
likely to habituate to sounds that are
predictable and unvarying. It is
important to note that habituation is
appropriately considered as a
‘‘progressive reduction in response to
stimuli that are perceived as neither
aversive nor beneficial,’’ rather than as,
more generally, moderation in response
to human disturbance (Bejder et al.,
2009). The opposite process is
sensitization, when an unpleasant
experience leads to subsequent
responses, often in the form of
avoidance, at a lower level of exposure.
As noted above, behavioral state may
affect the type of response. For example,
animals that are resting may show
greater behavioral change in response to
disturbing sound levels than animals
that are highly motivated to remain in
an area for feeding (Richardson et al.,
1995; Wartzok et al., 2004; NRC, 2005).
Controlled experiments with captive
marine mammals have showed
pronounced behavioral reactions,
including avoidance of loud sound
sources (Ridgway et al., 1997; Finneran
et al., 2003). Observed responses of wild
marine mammals to loud pulsed sound
sources (e.g., seismic airguns) have been
varied but often consist of avoidance
behavior or other behavioral changes
(Richardson et al., 1995; Morton and
Symonds, 2002; Nowacek et al., 2007).
Available studies show wide variation
in response to underwater sound;
therefore, it is difficult to predict
specifically how any given sound in a
particular instance might affect marine
mammals perceiving the signal. If a
marine mammal does react briefly to an
underwater sound by changing its
behavior or moving a small distance, the
impacts of the change are unlikely to be
significant to the individual, let alone
the stock or population. However, if a
sound source displaces marine
mammals from an important feeding or
breeding area for a prolonged period,
impacts on individuals and populations
could be significant (e.g., Lusseau and
Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad
categories of potential response, which
we describe in greater detail here, that
include alteration of dive behavior,
alteration of foraging behavior, effects to
breathing, interference with or alteration
of vocalization, avoidance, and flight.
Changes in dive behavior can vary
widely and 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; Nowacek et al.,
2004; Goldbogen et al., 2013a;
Goldbogen et al., 2013b). Variations in
dive behavior may reflect interruptions
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in biologically significant activities (e.g.,
foraging) or they may be of little
biological significance. The impact of an
alteration to dive behavior 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.
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; Nowacek et al.,
2004; Madsen et al., 2006; 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.
Variations in respiration naturally
vary with different behaviors and
alterations to breathing 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.
Various studies have shown that
respiration rates may either be
unaffected or could increase, depending
on the species and signal characteristics,
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 (e.g., Kastelein et al., 2005;
Kastelein et al., 2006). For example,
harbor porpoise’ respiration rate
increased in response to pile driving
sounds at and above a received
broadband SPL of 136 dB (zero-peak
SPL: 151 dB re 1 mPa; SEL of a single
strike: 127 dB re 1 mPa2-s) (Kastelein et
al., 2013).
Marine mammals vocalize for
different purposes and across multiple
modes, such as whistling, echolocation
click production, calling, and singing.
Changes in vocalization behavior in
response to anthropogenic noise can
occur for any of these modes and may
result from a need to compete with an
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increase in background noise or may
reflect increased vigilance or a startle
response. For example, in the presence
of potentially masking signals,
humpback whales and killer whales
have been observed to increase the
length of their songs (Miller et al., 2000;
Fristrup et al., 2003) or vocalizations
(Foote et al., 2004), respectively, while
North Atlantic right whales (Eubalaena
glacialis) 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). In some cases,
animals may cease sound production
during production of aversive signals
(Bowles et al., 1994).
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, and is one of
the most obvious manifestations of
disturbance in marine mammals
(Richardson et al., 1995). Avoidance
may be short-term, with animals
returning to the area once the noise has
ceased (e.g., Bowles et al., 1994; Morton
and Symonds, 2002). 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).
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; Bowers et al., 2018).
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, marine mammal strandings
(Evans and England, 2001). However, it
should be noted that response to a
perceived predator does not necessarily
invoke flight (Ford and Reeves, 2008),
and whether individuals are solitary or
in groups may influence the response.
Behavioral disturbance can also
impact marine mammals in more subtle
ways. Increased vigilance may result in
costs related to diversion of focus and
attention (i.e., when a response consists
of increased vigilance, it may come at
the cost of decreased attention to other
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critical behaviors such as foraging or
resting). These effects have generally not
been demonstrated for marine
mammals, but studies involving fishes
and terrestrial animals have shown that
increased vigilance may substantially
reduce feeding rates (e.g., Beauchamp
and Livoreil, 1997; Purser and Radford,
2011; Fritz et al., 2002). In addition,
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., Daan et al., 1996; Bradshaw et al.,
1998). However, Ridgway et al. (2006)
reported that increased vigilance in
bottlenose dolphins exposed to sound
over a 5-day period did not cause any
sleep deprivation or stress effects.
Many animals perform vital functions,
such as feeding, resting, traveling, and
socializing, on a diel cycle (24-hour
cycle). Disruption of such functions
resulting from reactions to stressors
such as sound exposure are more likely
to be significant if they last more than
one diel cycle or recur on subsequent
days (Southall et al., 2007).
Consequently, a behavioral response
lasting less than 1 day and not recurring
on subsequent days is not considered
particularly severe unless it could
directly affect reproduction or survival
(Southall et al., 2007). Note that there is
a difference between multi-day
substantive (i.e., meaningful) behavioral
reactions and multi-day anthropogenic
activities. For example, just because an
activity lasts for multiple days does not
necessarily mean that individual
animals are either exposed to activityrelated stressors for multiple days or,
further, exposed in a manner resulting
in sustained multi-day substantive
behavioral responses.
Behavioral Responses to Icebreaking
Noise—Ringed seals on pack ice showed
various behaviors when approached by
an icebreaking vessel. A majority of
seals dove underwater when the ship
was within 0.93 km (0.5 nm) while
others remained on the ice. However, as
icebreaking vessels came closer to the
seals, most dove underwater. Ringed
seals have also been observed foraging
in the wake of an icebreaking vessel
(Richardson et al., 1995) and may have
preferentially established breathing
holes in the ship tracks after the icebreaker moved through the area.
Previous observations and studies using
icebreaking ships provide a greater
understanding in how seal behavior
may be affected by a vessel transiting
through the area.
Adult ringed seals spend up to 20
percent of the time in subnivean lairs
during the winter season (Kelly et al.,
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2010a). Ringed seal pups spend about
50 percent of their time in the lair
during the nursing period (Lydersen and
Hammill, 1993). During the warm
season ringed seals haul out on the ice.
In a study of ringed seal haul out
activity by Born et al. (2002), ringed
seals spent 25–57 percent of their time
hauled out in June, which is during
their molting season. Ringed seal lairs
are typically used by individual seals
(haulout lairs) or by a mother with a
pup (birthing lairs); large lairs used by
many seals for hauling out are rare
(Smith and Stirling, 1975). If the nonimpulsive acoustic transmissions are
heard and are perceived as a threat,
ringed seals within subnivean lairs
could react to the sound in a similar
fashion to their reaction to other threats,
such as polar bears (their primary
predators), although the type of sound
would be novel to them. Responses of
ringed seals to a variety of humaninduced sounds (e.g., helicopter noise,
snowmobiles, dogs, people, and seismic
activity) have been variable; some seals
entered the water and some seals
remained in the lair. However, in all
instances in which observed seals
departed lairs in response to noise
disturbance, they subsequently
reoccupied the lair (Kelly et al., 1988).
Ringed seal mothers have a strong
bond with their pups and may
physically move their pups from the
birth lair to an alternate lair to avoid
predation, sometimes risking their lives
to defend their pups from potential
predators. If a ringed seal mother
perceives the proposed acoustic sources
as a threat, the network of multiple birth
and haulout lairs allows the mother and
pup to move to a new lair (Smith and
Stirling, 1975; Smith and Hammill,
1981). The acoustic sources from this
proposed action are not likely to impede
a ringed seal from finding a breathing
hole or lair, as captive seals have been
found to primarily use vision to locate
breathing holes and no effect to ringed
seal vision would occur from the
acoustic disturbance (Elsner et al., 1989;
Wartzok et al., 1992). It is anticipated
that a ringed seal would be able to
relocate to a different breathing hole
relatively easily without impacting their
normal behavior patterns.
Stress responses—An animal’s
perception of a threat may be sufficient
to trigger stress responses consisting of
some combination of behavioral
responses, autonomic nervous system
responses, neuroendocrine responses, or
immune responses (e.g., Selye, 1950;
Moberg, 2000). In many cases, an
animal’s first and sometimes most
economical (in terms of energetic costs)
response is behavioral avoidance of the
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potential stressor. Autonomic nervous
system responses to stress typically
involve changes in heart rate, blood
pressure, and gastrointestinal activity.
These responses have a relatively short
duration and may or may not have a
significant long-term effect on an
animal’s fitness.
Neuroendocrine stress responses often
involve the hypothalamus-pituitaryadrenal system. Virtually all
neuroendocrine 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,
altered metabolism, reduced immune
competence, and behavioral disturbance
(e.g., Moberg, 1987; Blecha, 2000).
Increases in the circulation of
glucocorticoids are also equated with
stress (Romano et al., 2004).
The primary distinction between
stress (which is adaptive and does not
normally place an animal at risk) and
‘‘distress’’ is the 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
functions. This state of distress will last
until the animal replenishes its
energetic reserves sufficient to restore
normal function.
Relationships between these
physiological mechanisms, animal
behavior, and the costs of stress
responses are well-studied through
controlled experiments for both
laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al.,
1998; Jessop et al., 2003; Krausman et
al., 2004; Lankford et al., 2005). Stress
responses due to exposure to
anthropogenic sounds or other stressors
and their effects on marine mammals
have also 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
vessel 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
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‘‘distress.’’ In addition, any animal
experiencing TTS would likely also
experience stress responses (NRC,
2003), however, distress is an unlikely
result of the proposed project based on
observations of marine mammals during
previous, similar projects in the region.
Auditory Masking—Since many
marine mammals rely on sound to find
prey, moderate social interactions, and
facilitate mating (Tyack, 2008), noise
from anthropogenic sound sources can
interfere with these functions, but only
if the noise spectrum overlaps with the
hearing sensitivity of the receiving
marine mammal (Southall et al., 2007;
Clark et al., 2009; Hatch et al., 2012).
Chronic exposure to excessive, though
not high-intensity, noise could cause
masking at particular frequencies for
marine mammals that utilize sound for
vital biological functions (Clark et al.,
2009). Acoustic masking is when other
noises such as from human sources
interfere 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,
navigation) (Richardson et al., 1995;
Erbe et al., 2016). Therefore, under
certain circumstances, marine mammals
whose acoustical sensors or
environment are being severely masked
could also be impaired from maximizing
their performance fitness in survival
and reproduction. 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 (Hotchkin and
Parks, 2013).
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
human-made, it may be considered
harassment when disrupting or altering
critical behaviors. It is important to
distinguish TTS and PTS, which persist
after the sound exposure, from masking,
which occurs during the sound
exposure. Because masking (without
resulting in TS) is not associated with
abnormal physiological function, it is
not considered a physiological effect,
but rather a potential behavioral effect
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(though not necessarily one that would
be associated with harassment).
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)
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, 2010; 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
(Hotchkin and Parks, 2013). 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).
Marine mammals at or near the
proposed project site may be exposed to
anthropogenic noise which may be a
source of masking. Vocalization changes
may result from a need to compete with
an increase in background noise and
include increasing the source level,
modifying the frequency, increasing the
call repetition rate of vocalizations, or
ceasing to vocalize in the presence of
increased noise (Hotchkin and Parks,
2013). For example, in response to loud
noise, beluga whales may shift the
frequency of their echolocation clicks to
prevent masking by anthropogenic noise
(Eickmeier and Vallarta, 2023).
Masking is more likely to occur in the
presence of broadband, relatively
continuous noise sources such as
vibratory pile driving. Energy
distribution of pile driving covers a
broad frequency spectrum, and sound
from pile driving would be within the
audible range of pinnipeds and
cetaceans present in the proposed action
area. While icebreaking during the
ONR’s proposed action may mask some
acoustic signals that are relevant to the
daily behavior of marine mammals, the
short-term duration (up to 8 days) and
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limited areas affected make it very
unlikely that the fitness of individual
marine mammals would be impacted.
Potential Effects on Prey—The marine
mammal species in the Study Area feed
on marine invertebrates and fish.
Studies of sound energy effects on
invertebrates are few, and primarily
identify behavioral responses. It is
expected that most marine invertebrates
would not sense the frequencies of the
acoustic transmissions from the acoustic
sources associated with the proposed
action. Although acoustic sources used
during the proposed action may briefly
impact individuals, intermittent
exposures to non-impulsive acoustic
sources are not expected to impact
survival, growth, recruitment, or
reproduction of widespread marine
invertebrate populations.
The fish species residing in the study
area include those that are closely
associated with the deep ocean habitat
of the Beaufort Sea. Nearly 250 marine
fish species have been described in the
Arctic, excluding the larger parts of the
sub-Arctic Bering, Barents, and
Norwegian Seas (Mecklenburg et al.,
2011). However, only about 30 are
known to occur in the Arctic waters of
the Beaufort Sea (Christiansen and
Reist, 2013). Although hearing
capability data only exist for fewer than
100 of the 32,000 named fish species,
current data suggest that most species of
fish detect sounds from 50 to 100 Hz,
with few fish hearing sounds above 4
kHz (Popper, 2008). It is believed that
most fish have the best hearing
sensitivity from 100 to 400 Hz (Popper,
2003). Fish species in the study area are
expected to hear the low-frequency
sources associated with the proposed
action, but most are not expected to
detect sound from the mid-frequency
sources. Human generated sound could
alter the behavior of a fish in a manner
than would affect its way of living, such
as where it tries to locate food or how
well it could find a mate. Behavioral
responses to loud noise could include a
startle response, such as the fish
swimming away from the source, the
fish ‘‘freezing’’ and staying in place, or
scattering (Popper, 2003). Misund
(1997) found that fish ahead of a ship
showed avoidance reactions at ranges of
49–149 m (160–489 ft). Avoidance
behavior of vessels, vertically or
horizontally in the water column, has
been reported for cod and herring, and
was attributed to vessel noise. While
acoustic sources associated with the
proposed action may influence the
behavior of some fish species, other fish
species may be equally unresponsive.
Overall effects to fish from the proposed
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action would be localized, temporary,
and infrequent.
Effects to Physical and Foraging
Habitat—Ringed seals haul out on pack
ice during the spring and summer to
molt (Reeves et al., 2002; Born et al.,
2002). Additionally, some studies
suggested that ringed seals might
preferentially establish breathing holes
in ship tracks after vessels move
through the area (Alliston, 1980;
Alliston, 1981). The amount of ice
habitat disturbed by activities is small
relative to the amount of overall habitat
available and there will be no
permanent or longer-term loss or
modification of physical ice habitat
used by ringed seals. Vessel movement
would have minimal effect on physical
beluga habitat as beluga habitat is solely
within the water column. Furthermore,
the deployed sources that would remain
in use after the vessels have left the
survey area have low duty cycles and
lower source levels, and any impacts to
the acoustic habitat of marine mammals
would be minimal.
Estimated Take of Marine Mammals
This section provides an estimate of
the number of incidental takes proposed
for authorization through the IHA,
which will inform NMFS’ consideration
of the negligible impact determinations
and impacts on subsistence uses.
Harassment is the only type of take
expected to result from these activities.
For this 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 the behavioral patterns are
abandoned or significantly altered
(Level B harassment).
Authorized takes would be by Level B
harassment only, in the form of direct
behavioral disturbances and/or TTS for
individual marine mammals resulting
from exposure to active acoustic
transmissions and icebreaking. Based on
the nature of the activity, Level A
harassment is neither anticipated nor
proposed to be authorized.
As described previously, no serious
injury or mortality is anticipated or
proposed to be authorized for this
activity. Below we describe how the
proposed take numbers are estimated.
For acoustic impacts, generally
speaking, we estimate take by
considering: (1) acoustic thresholds
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above which NMFS believes the best
available science indicates marine
mammals will be behaviorally harassed
or incur some degree of permanent
hearing impairment; (2) the area or
volume of water that will be ensonified
above these levels in a day; (3) the
density or occurrence of marine
mammals within these ensonified areas;
and, (4) the number of days of activities.
We note that while these factors can
contribute to a basic calculation to
provide an initial prediction of potential
takes, additional information that can
qualitatively inform take estimates is
also sometimes available (e.g., previous
monitoring results or average group
size). Below, we describe the factors
considered here in more detail and
present the proposed take estimates.
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Acoustic Thresholds
NMFS recommends the use of
acoustic thresholds that identify the
received level of underwater sound
above which exposed marine mammals
would be reasonably expected to be
behaviorally harassed (equated to Level
B harassment) or to incur PTS of some
degree (equated to Level A harassment).
Thresholds have also been developed
identifying the received level of in-air
sound above which exposed pinnipeds
would likely be behaviorally harassed.
Level B Harassment
Though significantly driven by
received level, the onset of behavioral
disturbance from anthropogenic noise
exposure is also informed to varying
degrees by other factors related to the
source or exposure context (e.g.,
frequency, predictability, duty cycle,
duration of the exposure, signal-to-noise
ratio, distance to the source), the
environment (e.g., bathymetry, other
noises in the area, predators in the area),
and the receiving animals (hearing,
motivation, experience, demography,
life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007;
Southall et al., 2021; Ellison et al.,
2012). Based on what the available
science indicates and the practical need
to use a threshold based on a metric that
is both predictable and measurable for
most activities, NMFS typically uses a
generalized acoustic threshold based on
received level to estimate the onset of
behavioral harassment. NMFS generally
predicts that marine mammals are likely
to be behaviorally harassed in a manner
considered to be Level B harassment
when exposed to underwater
anthropogenic noise above root-meansquared pressure received levels (RMS
SPL) of 120 dB re 1 mPa for continuous
(e.g., vibratory pile driving, drilling) and
above RMS SPL 160 dB re 1 mPa for non-
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explosive impulsive (e.g., seismic
airguns) or intermittent (e.g., scientific
sonar) sources. Generally speaking,
Level B harassment estimates based on
these behavioral harassment thresholds
are expected to include any likely takes
by TTS as, in most cases, the likelihood
of TTS occurs at distances from the
source less than those at which
behavioral harassment is likely. TTS of
a sufficient degree can manifest as
behavioral harassment, as reduced
hearing sensitivity and the potential
reduced opportunities to detect
important signals (conspecific
communication, predators, prey) may
result in changes in behavior patterns
that would not otherwise occur.
In this case, NMFS is proposing to
adopt the ONR’s approach to estimating
incidental take by Level B harassment
from the active acoustic sources for this
action, which includes use of dose
response functions. The ONR’s dose
response functions were developed to
estimate take from sonar and similar
transducers, but are not applicable to
icebreaking. Multi-year research efforts
have conducted sonar exposure studies
for odontocetes and mysticetes (Miller
et al., 2012; Sivle et al., 2012). Several
studies with captive animals have
provided data under controlled
circumstances for odontocetes and
pinnipeds (Houser et al., 2013b; Houser
et al., 2013a). Moretti et al. (2014)
published a beaked whale doseresponse curve based on passive
acoustic monitoring of beaked whales
during U.S. Navy training activity at
Atlantic Underwater Test and
Evaluation Center during actual AntiSubmarine Warfare exercises. This
information necessitated the update of
the behavioral response criteria for the
U.S. Navy’s environmental analyses.
Southall et al. (2007), and more
recently (Southall et al., 2019),
synthesized data from many past
behavioral studies and observations to
determine the likelihood of behavioral
reactions at specific sound levels. While
in general, the louder the sound source
the more intense the behavioral
response, it was clear that the proximity
of a sound source and the animal’s
experience, motivation, and
conditioning were also critical factors
influencing the response (Southall et al.,
2007; Southall et al., 2019). After
examining all of the available data, the
authors felt that the derivation of
thresholds for behavioral response
based solely on exposure level was not
supported because context of the animal
at the time of sound exposure was an
important factor in estimating response.
Nonetheless, in some conditions,
consistent avoidance reactions were
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66083
noted at higher sound levels depending
on the marine mammal species or group
allowing conclusions to be drawn.
Phocid seals showed avoidance
reactions at or below 190 dB re 1 mPa
at 1 m; thus, seals may actually receive
levels adequate to produce TTS before
avoiding the source.
Odontocete behavioral criteria for
non-impulsive sources were updated
based on controlled exposure studies for
dolphins and sea mammals, sonar, and
safety (3S) studies where odontocete
behavioral responses were reported after
exposure to sonar (Miller et al., 2011;
Miller et al., 2012; Antunes et al., 2014;
Miller et al., 2014; Houser et al., 2013b).
For the 3S study, the sonar outputs
included 1–2 kHz up- and down-sweeps
and 6–7 kHz up-sweeps; source levels
were ramped up from 152–158 dB re 1
mPa to a maximum of 198–214 re 1 mPa
at 1 m. Sonar signals were ramped up
over several pings while the vessel
approached the mammals. The study
did include some control passes of ships
with the sonar off to discern the
behavioral responses of the mammals to
vessel presence alone versus active
sonar.
The controlled exposure studies
included exposing the Navy’s trained
bottlenose dolphins to mid-frequency
sonar while they were in a pen. Midfrequency sonar was played at six
different exposure levels from 125–185
dB re 1 mPa (RMS). The behavioral
response function for odontocetes
resulting from the studies described
above has a 50 percent probability of
response at 157 dB re 1 mPa.
Additionally, distance cutoffs (20 km for
MF cetaceans) were applied to exclude
exposures beyond which the potential
of significant behavioral responses is
considered to be unlikely.
The pinniped behavioral threshold
was updated based on controlled
exposure experiments on the following
captive animals: hooded seal
(Cystophora cristata), gray seal
(Halichoerus grypus), and California sea
lion (Götz et al., 2010; Houser et al.,
2013a; Kvadsheim et al., 2010). Hooded
seals were exposed to increasing levels
of sonar until an avoidance response
was observed, while the grey seals were
exposed first to a single received level
multiple times, then an increasing
received level. Each individual
California sea lion was exposed to the
same received level ten times. These
exposure sessions were combined into a
single response value, with an overall
response assumed if an animal
responded in any single session. The
resulting behavioral response function
for pinnipeds has a 50 percent
probability of response at 166 dB re 1
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mPa. Additionally, distance cutoffs (10
km for pinnipeds) were applied to
exclude exposures beyond which the
potential of significant behavioral
responses is considered unlikely. For
additional information regarding marine
mammal thresholds for PTS and TTS
onset, please see NMFS (2018) and table
6.
Empirical evidence has not shown
responses to non-impulsive acoustic
sources that would constitute take
beyond a few km from a non-impulsive
acoustic source, which is why NMFS
and the Navy conservatively set
distance cutoffs for pinnipeds and midfrequency cetaceans (U.S. Department of
the Navy, 2017a). The cutoff distances
for fixed sources are different from those
for moving sources, as they are treated
as individual sources in ONR’s
modeling given that the distance
between them is significantly greater
than the range to which environmental
effects can occur. Fixed source cutoff
distances used were 5 km (2.7 nm) for
pinnipeds and 10 km (5.4 nm) for
beluga whales (table 5). As some of the
on-site drifting sources could come
closer together, the drifting source
cutoffs applied were 10 km (5.4 nm) for
pinnipeds and 20 km (10.8 nm) for
beluga whales (table 5). Regardless of
the received level at that distance, take
is not estimated to occur beyond these
cutoff distances. Range to thresholds
were calculated for the noise associated
with icebreaking in the study area.
These all fall within the same cutoff
distances as non-impulsive acoustic
sources; range to behavioral threshold
for both beluga whales and ringed seal
were under 5 km (2.7 nm), and range to
TTS threshold for both under 15 m (49.2
ft) (table 5).
TABLE 5—CUTOFF DISTANCES AND ACOUSTIC THRESHOLDS IDENTIFYING THE ONSET OF BEHAVIORAL DISTURBANCE, TTS,
AND PTS FOR NON-IMPULSIVE SOUND SOURCES
Hearing group
Species
Fixed source
behavioral
threshold
cutoff
distance a
Drifting
source
behavioral
threshold
cutoff
distance a
Mid-frequency
cetaceans.
Beluga whale
10 km (5.4
nm).
20 km (10.8
nm).
Phocidae (in
water).
Ringed seal ..
5 km (2.7 nm)
10 km (5.4
nm).
Icebreaking
source
behavioral
threshold cutoff
distance a b
Behavioral criteria:
Non-impulsive
acoustic sources
Mid-frequency BRF
dose-response function *.
Pinniped dose-response function *.
Behavioral
criteria:
icebreaking
sources
Physiological
criteria: onset
TTS
Physiological
criteria: onset
PTS
5 km (2.7 nm)
120 dB re 1 μPa
step function.
178 dB
SELcum.
198 dB
SELcum.
5 km (2.7 nm)
120 dB re 1 μPa
step function.
181 dB
SELcum.
201 dB
SELcum.
Note: The threshold values provided are assumed for when the source is within the animal’s best hearing sensitivity. The exact threshold varies based on the overlap of the source and the frequency weighting (see figure 6–1 in IHA application).
a Take is not estimated to occur beyond these cutoff distances, regardless of the received level.
b Range to TTS threshold for both hearing groups for the noise associated with icebreaking in the Study Area is under 15 m (49.2 ft).
Level A Harassment
NMFS’ Technical Guidance for
Assessing the Effects of Anthropogenic
Sound on Marine Mammal Hearing
(Version 2.0) (Technical Guidance,
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 nonimpulsive). The ONR’s proposed action
includes the use of non-impulsive
(active sonar and icebreaking) sources;
however, Level A harassment is not
expected as a result of the proposed
activities based on modeling, as
described below, nor is it proposed to be
authorized by NMFS.
These thresholds are provided in the
table below. The references, analysis,
and methodology used in the
development of the thresholds are
described in NMFS’ 2018 Technical
Guidance, which may be accessed at:
https://www.fisheries.noaa.gov/
national/marine-mammal-protection/
marine-mammal-acoustic-technicalguidance.
TABLE 6—THRESHOLDS IDENTIFYING THE ONSET OF PERMANENT THRESHOLD SHIFT
PTS onset acoustic thresholds *
(received level)
Hearing group
Impulsive
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Low-Frequency (LF) Cetaceans ......................................
Mid-Frequency (MF) Cetaceans ......................................
High-Frequency (HF) Cetaceans .....................................
Phocid Pinnipeds (PW) (Underwater) .............................
Otariid Pinnipeds (OW) (Underwater) .............................
Cell
Cell
Cell
Cell
Cell
1:
3:
5:
7:
9:
Lpk,flat:
Lpk,flat:
Lpk,flat:
Lpk,flat:
Lpk,flat:
219
230
202
218
232
dB;
dB;
dB;
dB;
dB;
Non-impulsive
LE,LF,24h: 183 dB .........................
LE,MF,24h: 185 dB ........................
LE,HF,24h: 155 dB ........................
LE,PW,24h: 185 dB .......................
LE,OW,24h: 203 dB .......................
Cell
Cell
Cell
Cell
Cell
2: LE,LF,24h: 199 dB.
4: LE,MF,24h: 198 dB.
6: LE,HF,24h: 173 dB.
8: LE,PW,24h: 201 dB.
10: LE,OW,24h: 219 dB.
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds associated with impulsive sounds, these thresholds should
also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 μPa, and cumulative sound exposure level (LE) has a reference value of 1 μPa2s.
In this table, thresholds are abbreviated to reflect American National Standards Institute (ANSI) standards. However, peak sound pressure is defined by ANSI as incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ‘‘flat’’ is being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized hearing range. The subscript associated
with cumulative sound exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF
cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The cumulative sound exposure level
thresholds could be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it is valuable for
action proponents to indicate the conditions under which these acoustic thresholds will be exceeded.
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Quantitative Modeling
The Navy performed a quantitative
analysis to estimate the number of
marine mammals likely to be exposed to
underwater acoustic transmissions
above the previously described
threshold criteria during the proposed
action. Inputs to the quantitative
analysis included marine mammal
density estimates obtained from the
Kaschner et al. (2006) habitat suitability
model and (Cañadas et al., 2020),
marine mammal depth occurrence (U.S.
Department of the Navy, 2017b),
oceanographic and mammal hearing
data, and criteria and thresholds for
levels of potential effects. The
quantitative analysis consists of
computer modeled estimates and a postmodel analysis to determine the number
of potential animal exposures. The
model calculates sound energy
propagation from the proposed nonimpulsive acoustic sources, the sound
received by animat (virtual animal)
dosimeters representing marine
mammals distributed in the area around
the modeled activity, and whether the
sound received by animats exceeds the
thresholds for effects.
The Navy developed a set of software
tools and compiled data for estimating
acoustic effects on marine mammals
without consideration of behavioral
avoidance or mitigation. These tools and
data sets serve as integral components of
the Navy Acoustic Effects Model
(NAEMO). In NAEMO, animats are
distributed non-uniformly based on
species-specific density, depth
distribution, and group size information
and animats record energy received at
their location in the water column. A
fully three-dimensional environment is
used for calculating sound propagation
and animat exposure in NAEMO. Sitespecific bathymetry, sound speed
profiles, wind speed, and bottom
properties are incorporated into the
propagation modeling process. NAEMO
calculates the likely propagation for
various levels of energy (sound or
pressure) resulting from each source
used during the training event.
NAEMO then records the energy
received by each animat within the
energy footprint of the event and
calculates the number of animats having
received levels of energy exposures that
fall within defined impact thresholds.
Predicted effects on the animats within
a scenario are then tallied and the
highest order effect (based on severity of
criteria; e.g., PTS over TTS) predicted
for a given animat is assumed. Each
scenario, or each 24-hour period for
scenarios lasting greater than 24 hours
is independent of all others, and
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therefore, the same individual marine
mammal (as represented by an animat in
the model environment) could be
impacted during each independent
scenario or 24-hour period. In few
instances, although the activities
themselves all occur within the
proposed study location, sound may
propagate beyond the boundary of the
study area. Any exposures occurring
outside the boundary of the study area
are counted as if they occurred within
the study area boundary. NAEMO
provides the initial estimated impacts
on marine species with a static
horizontal distribution (i.e., animats in
the model environment do not move
horizontally).
There are limitations to the data used
in the acoustic effects model, and the
results must be interpreted within this
context. While the best available data
and appropriate input assumptions have
been used in the modeling, when there
is a lack of definitive data to support an
aspect of the modeling, conservative
modeling assumptions have been
chosen (i.e., assumptions that may
result in an overestimate of acoustic
exposures):
• Animats are modeled as being
underwater, stationary, and facing the
source and therefore always predicted to
receive the maximum potential sound
level at a given location (i.e., no
porpoising or pinnipeds’ heads above
water);
• Animats do not move horizontally
(but change their position vertically
within the water column), which may
overestimate physiological effects such
as hearing loss, especially for slow
moving or stationary sound sources in
the model;
• Animats are stationary horizontally
and therefore do not avoid the sound
source, unlike in the wild where
animals would most often avoid
exposures at higher sound levels,
especially those exposures that may
result in PTS;
• Multiple exposures within any 24hour period are considered one
continuous exposure for the purposes of
calculating potential threshold shift,
because there are not sufficient data to
estimate a hearing recovery function for
the time between exposures; and
• Mitigation measures were not
considered in the model. In reality,
sound-producing activities would be
reduced, stopped, or delayed if marine
mammals are detected by visual
monitoring.
Due to these inherent model
limitations and simplifications, modelestimated results should be further
analyzed, considering such factors as
the range to specific effects, avoidance,
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and the likelihood of successfully
implementing mitigation measures. This
analysis uses a number of factors in
addition to the acoustic model results to
predict acoustic effects on marine
mammals, as described below in the
Marine Mammal Occurrence and Take
Estimation section.
The underwater radiated noise
signature for icebreaking in the central
Arctic Ocean by CGC HEALY during
different types of ice-cover was
characterized in Roth et al. (2013). The
radiated noise signatures were
characterized for various fractions of ice
cover. For modeling, the 8/10 and 3/10
ice cover were used. Each modeled day
of icebreaking consisted of 16 hours of
8/10 ice cover and 8 hours of 3/10 ice
cover. The sound signature of the 5/10
icebreaking activities, which would
correspond to half-power icebreaking,
was not reported in Roth et al. (2013);
therefore, the full-power signature was
used as a conservative proxy for the
half-power signature. Icebreaking was
modeled for 8 days total. Since ice
forecasting cannot be predicted more
than a few weeks in advance, it is
unknown if icebreaking would be
needed to deploy or retrieve the sources
after 1 year of transmitting. Therefore,
the potential for an icebreaking cruise
on CGC HEALY was conservatively
analyzed within the ONR’s request for
an IHA. As the R/V Sikuliaq is not
capable of icebreaking, acoustic noise
created by icebreaking is only modeled
for the CGC HEALY. Figures 5a and 5b
in Roth et al. (2013) depict the source
spectrum level versus frequency for
8/10 and 3/10 ice cover, respectively.
The sound signature of each of the ice
coverage levels was broken into 1-octave
bins (table 7). In the model, each bin
was included as a separate source on the
modeled vessel. When these
independent sources go active
concurrently, they simulate the sound
signature of CGC HEALY. The modeled
source level summed across these bins
was 196.2 dB for the 8/10 signature and
189.3 dB for the 3/10 ice signature.
These source levels are a good
approximation of the icebreaker’s
observed source level (provided in
figure 4b of Roth et al. (2013). Each
frequency and source level was modeled
as an independent source, and applied
simultaneously to all of the animats
within NAEMO. Each second was
summed across frequency to estimate
SPLRMS. Any animat exposed to sound
levels greater than 120 dB was
considered a take by Level B
harassment. For PTS and TTS,
determinations, sound exposure levels
were summed over the duration of the
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test and the transit to the deep water
deployment area. The method of
quantitative modeling for icebreaking is
considered to be a conservative
approach; therefore, the number of takes
estimated for icebreaking are likely an
overestimate and would not be expected
to reach that level.
TABLE 7—MODELED BINS FOR 8/10
ICE COVERAGE (FULL POWER) AND
3/10 ICE COVERAGE (QUARTER
POWER) ICEBREAKING ON CGC
HEALY
8/10
source
level
(dB)
Frequency
(Hz)
25 ......................
50 ......................
100 ....................
200 ....................
400 ....................
800 ....................
1,600 .................
3,200 .................
6,400 .................
12,800 ...............
3/10
source
level
(dB)
189
188
189
190
188
183
177
176
172
167
187
182
179
177
175
170
166
171
168
164
Non-Impulsive Acoustic Analysis
Most likely, individuals affected by
acoustic transmission would move away
from the sound source. Ringed seals
may be temporarily displaced from their
subnivean lairs in the winter, but a
pinniped would have to be within 5 km
(2.7 nm) of a moored source or within
10 km (5.4 nm) of a drifting source for
any behavioral reaction. Any effects
experienced by individual pinnipeds
are anticipated to be short-term
disturbance of normal behavior, or
temporary displacement or disruption of
animals that may be near elements of
the proposed action.
Of historical sightings registered in
the Ocean Biodiversity Information
System Spatial Ecological Analysis of
Megavertebrate Populations (OBIS–
SEAMAP database) (Halpin et al., 2009)
in the ARA Study Area, nearly all (99
percent) occurred in summer and fall
seasons. However, there is no
documentation to prove that this is
because ringed seals would all move out
of the Study Area during the cold
season, or if the lack of sightings is due
to the harsh environment and ringed
seal behavior being prohibitive factors
for cold season surveying. OBIS–
SEAMAP reports 542 animals sighted
over 150 records in the ARA Study Area
across all years and seasons. Taking the
average of 542 animals in 150 records
aligns with survey data from previous
ARA cruises that show up to three
ringed seals (or small, unidentified
pinnipeds assumed to be ringed seals)
per day sighted in the Study Area. To
account for any unsighted animals, that
number was rounded up to 4. Assuming
that four animals would be present in
the Study Area, a rough estimate of
density can be calculated using the
overall Study Area size:
4 ringed seals ÷ 48,725 km2 =
0.00008209 ringed seals/km2
The area of influence surrounding
each moored source would be 78.5 km2,
and the area of influence surrounding
each drifting source would be 314 km2.
The total area of influence on any given
day from non-impulsive acoustic
sources would be 942 km2. The number
of ringed seals that could be taken daily
can be calculated:
0.00008209 ringed seals/km2 × 942 km2
= 0.077 ringed seals/day
To be conservative, the ONR has
assumed that one ringed seal would be
exposed to acoustic transmissions above
the threshold for Level B harassment,
and that each would be exposed each
day of the proposed action (365 days
total). Unlike the NAEMO modeling
approach used to estimate ringed seal
takes in previous ARA IHAs, the
occurrence method used in this ARA
IHA request does not support the
differentiation between behavioral or
TTS exposures. Therefore, all takes are
classified as Level B harassment and not
further distinguished. Modeling for all
previous years of ARA activities did not
result in any estimated Level A
harassment. NMFS has no reason to
expect that the ARA activities during
the effective dates of this IHA would be
more likely to result in Level A
harassment. Therefore, no Level A
harassment is anticipated due to the
proposed action.
Marine Mammal Occurrence and Take
Estimation
In this section we provide information
about the occurrence of marine
mammals, including density or other
relevant information which will inform
the take calculations. We also describe
how the marine mammal occurrence
information is synthesized to produce a
quantitative estimate of the take that is
reasonably likely to occur and proposed
for authorization.
The beluga whale density numbers
utilized for quantitative acoustic
modeling are from the Navy Marine
Species Density Database (U.S.
Department of the Navy, 2014). Where
available (i.e., June through 15 October
over the continental shelf primarily),
density estimates used were from Duke
density modeling based upon linetransect surveys (Cañadas et al., 2020).
The remaining seasons and geographic
area were based on the habitat-based
modeling by Kaschner (2004) and
Kaschner et al. (2006). Density for
beluga whales was not distinguished by
stock and varied throughout the project
area geographically and monthly; the
range of densities in the Study Area is
shown in table 8. The density estimates
for ringed seals are based on the habitat
suitability modeling by Kaschner (2004)
and Kaschner et al. (2006) and shown in
table 8.
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TABLE 8—DENSITY ESTIMATES OF IMPACTED SPECIES
Density
(animals/km2)
Common name
Stock
Beluga whale ......................................................................
Beluga whale ......................................................................
Ringed seal .........................................................................
Beaufort Sea ......................................................................
Eastern Chukchi Sea .........................................................
Arctic ...................................................................................
Take of all species would occur by
Level B harassment only. NAEMO was
previously used to produce a qualitative
estimate of PTS, TTS, and behavioral
exposures for ringed seals. For this
proposed action, a new approach that
utilizes sighting data from previous
surveys conducted within the Study
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Area was used to estimate Level B
harassment associated with nonimpulsive acoustic sources (see section
6.4.3 of the IHA application). NAEMO
modeling is still used to provide
estimated takes of beluga whales
associated with non-impulsive acoustic
sources, as well as provide take
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0.000506 to 0.5176
0.000506 to 0.5176
0.1108 to 0.3562
estimations associated with icebreaking
for both species. Table 9 shows the total
number of requested takes by Level B
harassment that NMFS proposes to
authorize for both beluga whale stocks
and the Arctic ringed seal stock based
upon NAEMO modeled results.
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area throughout the year (Hauser et al.,
2014). Based upon the limited
information available regarding the
expected spatial distributions of each
stock within the study area, take has
been apportioned equally to each stock
Density estimates for beluga whales
are equal as estimates were not
distinguished by stock (Kaschner, 2004;
Kaschner et al., 2006). The ranges of the
Beaufort Sea and Eastern Chukchi Sea
beluga whales vary within the study
(table 9). In addition, in NAEMO,
animats do not move horizontally or
react in any way to avoid sound,
therefore, the current model may
overestimate non-impulsive acoustic
impacts.
TABLE 9—PROPOSED TAKE BY LEVEL B HARASSMENT
Active
acoustics
Species
Stock
Beluga whale .........................
Beluga whale .........................
Ringed seal ...........................
Beaufort Sea .........................
Chukchi Sea ..........................
Arctic .....................................
a Acoustic
I
Icebreaking
(behavioral)
Icebreaking
(TTS)
a 177
a 21
a 177
a 21
365
I
538
I
Total proposed
take
0
0
1
99
99
904
I
SAR
abundance
I
39,258
13,305
(171,
418)
b UND
Percentage of
population
I
<1
<1
<1
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and icebreaking exposures to beluga whales were not modeled at the stock level as the density value is not distinguished by stock in the Arctic for
beluga whales (U.S. Department of the Navy, 2014). Estimated take of beluga whales due to active acoustics is 177 and 21 due to icebreaking activities, totaling 198
takes of beluga whales. The total take was evenly distributed among the two stocks.
b A reliable population estimate for the entire Arctic stock of ringed seals is not available and NMFS SAR lists it as Undetermined (UND). Using a sub-sample of
data collected from the U.S. portion of the Bering Sea (Conn et al., 2014), an abundance estimate of 171,418 ringed seals has been calculated but this estimate does
not account for availability bias due to seals in the water or in the shore-fast ice zone at the time of the survey. The actual number of ringed seals in the U.S. portion
of the Bering Sea is likely much higher. Using the minimum population size (Nmin = 158,507) based upon this negatively biased population estimate, the PBR is calculated to be 4,755 seals, although this is also a negatively biased estimate.
Proposed Mitigation
In order to issue an IHA under section
101(a)(5)(D) of the MMPA, NMFS must
set forth the permissible methods of
taking pursuant to the activity, and
other means of effecting the least
practicable impact on the species or
stock and its habitat, paying particular
attention to rookeries, mating grounds,
and areas of similar significance, and on
the availability of the species or stock
for taking for certain subsistence uses.
NMFS regulations require applicants for
incidental take authorizations to include
information about the availability and
feasibility (economic and technological)
of equipment, methods, and manner of
conducting the activity or other means
of effecting the least practicable adverse
impact upon the affected species or
stocks, and their habitat (50 CFR
216.104(a)(11)). The 2004 NDAA
amended the MMPA as it relates to
military readiness activities and the
incidental take authorization process
such that ‘‘least practicable impact’’
shall include consideration of personnel
safety, practicality of implementation,
and impact on the effectiveness of the
military readiness activity.
In evaluating how mitigation may or
may not be appropriate to ensure the
least practicable adverse impact on
species or stocks and their habitat, as
well as subsistence uses where
applicable, NMFS considers two
primary factors:
(1) The manner in which, and the
degree to which, the successful
implementation of the measure(s) is
expected to reduce impacts to marine
mammals, marine mammal species or
stocks, and their habitat, as well as
subsistence uses. This considers the
nature of the potential adverse impact
being mitigated (likelihood, scope,
range). It further considers the
likelihood that the measure will be
effective if implemented (probability of
accomplishing the mitigating result if
implemented as planned), the
likelihood of effective implementation
(probability implemented as planned),
and;
(2) The practicability of the measures
for applicant implementation, which
may consider such things as cost,
impact on operations, and, in the case
of a military readiness activity,
personnel safety, practicality of
implementation, and impact on the
effectiveness of the military readiness
activity.
The following measures are proposed
for this IHA:
• All vessels operated by or for the
Navy must have personnel assigned to
stand watch at all times while
underway. Watch personnel must
employ visual search techniques using
binoculars. While underway and while
using active acoustic sources/towed inwater devices, at least one person with
access to binoculars is required to be on
watch at all times.
• Vessel captains and vessel
personnel must remain alert at all times,
proceed with extreme caution, and
operate at a safe speed so that the vessel
can take proper and effective action to
avoid any collisions with marine
mammals.
• During moored and drifting
acoustic source deployment and
recovery, ONR must implement a
mitigation zone of 55 m (180 ft) around
the deployed source. Deployment and
recovery must cease if a marine
mammal is visually deterred within the
mitigation zone. Deployment and
recovery may recommence if any one of
the following conditions are met:
Æ The animal is observed exiting the
mitigation zone;
Æ The animal is thought to have
exited the mitigation zone based on a
determination of its course, speed, and
movement relative to the sound source;
Æ The mitigation zone has been clear
from any additional sightings for a
period of 15 minutes for pinnipeds and
30 minutes for cetaceans.
• Vessels must avoid approaching
marine mammals head-on and must
maneuver to maintain a mitigation zone
of 457 m (500 yards) around all
observed cetaceans and 183 m (200
yards) around all other observed marine
mammals, provided it is safe to do so.
• Activities must cease if a marine
mammal species for which take was not
authorized, or a species for which
authorization was granted but the
authorized number of takes have been
met, is observed approaching or within
the mitigation zone (table 10). Activities
must not resume until the animal is
confirmed to have left the area.
• Vessel captains must maintain atsea communication with subsistence
hunters to avoid conflict of vessel
transit with hunting activity.
TABLE 10—PROPOSED MITIGATION ZONES
Activity and/or effort type
Species
Acoustic source deployment and recovery, stationary ...........................
Beluga whale .................................
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Mitigation zone
55 m (180 ft).
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TABLE 10—PROPOSED MITIGATION ZONES—Continued
Activity and/or effort type
Species
Acoustic source deployment and recovery, stationary ...........................
Transit ......................................................................................................
Transit ......................................................................................................
Ringed seal ....................................
Beluga whale .................................
Ringed seal ....................................
Based on our evaluation of the
applicant’s proposed measures, NMFS
has preliminarily determined that the
proposed mitigation measures provide
the means of effecting the least
practicable impact on the affected
species or stocks and their habitat,
paying particular attention to rookeries,
mating grounds, areas of similar
significance, and on the availability of
such species or stock for subsistence
uses.
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Proposed Monitoring and Reporting
In order to issue an IHA for an
activity, section 101(a)(5)(D) of the
MMPA states that 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 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 while conducting the activities.
Effective reporting is critical both to
compliance as well as ensuring that the
most value is obtained from the required
monitoring.
Monitoring and reporting
requirements prescribed by NMFS
should contribute to improved
understanding of one or more of the
following:
• Occurrence of marine mammal
species or stocks in the area in which
take is anticipated (e.g., presence,
abundance, distribution, density);
• Nature, scope, or context of likely
marine mammal exposure to potential
stressors/impacts (individual or
cumulative, acute or chronic), through
better understanding of: (1) action or
environment (e.g., source
characterization, propagation, ambient
noise); (2) affected species (e.g., life
history, dive patterns); (3) co-occurrence
of marine mammal species with the
activity; or (4) biological or behavioral
context of exposure (e.g., age, calving or
feeding areas);
• Individual marine mammal
responses (behavioral or physiological)
to acoustic stressors (acute, chronic, or
cumulative), other stressors, or
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cumulative impacts from multiple
stressors;
• How anticipated responses to
stressors impact either: (1) long-term
fitness and survival of individual
marine mammals; or (2) populations,
species, or stocks;
• Effects on marine mammal habitat
(e.g., marine mammal prey species,
acoustic habitat, or other important
physical components of marine
mammal habitat); and,
• Mitigation and monitoring
effectiveness.
The Navy has coordinated with NMFS
to develop an overarching program plan
in which specific monitoring would
occur. This plan is called the Integrated
Comprehensive Monitoring Program
(ICMP) (U.S. Department of the Navy,
2011). The ICMP has been developed in
direct response to Navy permitting
requirements established through
various environmental compliance
efforts. As a framework document, the
ICMP applies by regulation to those
activities on ranges and operating areas
for which the Navy is seeking or has
sought incidental take authorizations.
The ICMP is intended to coordinate
monitoring efforts across all regions and
to allocate the most appropriate level
and type of effort based on a set of
standardized research goals, and in
acknowledgement of regional scientific
value and resource availability.
The ICMP is focused on Navy training
and testing ranges where the majority of
Navy activities occur regularly as those
areas have the greatest potential for
being impacted. ONR’s ARA in
comparison is a less intensive test with
little human activity present in the
Arctic. Human presence is limited to the
deployment of sources that would take
place over several weeks. Additionally,
due to the location and nature of the
testing, vessels and personnel would not
be within the study area for an extended
period of time. As such, more extensive
monitoring requirements beyond the
basic information being collected would
not be feasible as it would require
additional personnel and equipment to
locate seals and a presence in the Arctic
during a period of time other then what
is planned for source deployment.
However, ONR will record all
observations of marine mammals,
including the marine mammal’s species
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Mitigation zone
55 m (180 ft).
457 m (500 yards).
183 m (200 yards).
identification, location (latitude/
longitude), behavior, and distance from
project activities. ONR will also record
date and time of sighting. This
information is valuable in an area with
few recorded observations.
Marine mammal monitoring must be
conducted in accordance with the
Navy’s ICMP and the proposed IHA:
• While underway, all vessels must
have at least one person trained through
the U.S. Navy Marine Species
Awareness Training Program on watch
during all activities;
• Watch personnel must use
standardized data collection forms,
whether hard copy or electronic. Watch
personnel must distinguish between
sightings that occur during transit or
during deployment or recovery of
acoustic sources. Data must be recorded
on all days of activities, even if marine
mammals are not sighted;
• At minimum, the following
information must be recorded:
Æ Vessel name;
Æ Watch personnel names and
affiliation;
Æ Effort type (i.e., transit,
deployment, recovery); and
Æ Environmental conditions (at the
beginning of watch stander shift and
whenever conditions change
significantly), including Beaufort Sea
State (BSS) and any other relevant
weather conditions, including cloud
cover, fog, sun glare, and overall
visibility to the horizon.
• Upon visual observation of any
marine mammal, the following
information must be recorded:
Æ Date/time of sighting;
Æ Identification of animal (e.g.,
genus/species, lowest possible
taxonomic level, or unidentified) and
the composition of the group if there is
a mix of species;
Æ Location (latitude/longitude) of
sighting;
Æ Estimated number of animals (high/
low/best);
Æ Description (as many
distinguishing features as possible of
each individual seen, including length,
shape, color, pattern, scars or markings,
shape and size of dorsal fin, shape of
head, and blow characteristics);
Æ Detailed behavior observations
(e.g., number of blows/breaths, number
of surfaces, breaching, spyhopping,
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diving, feeding, traveling; as explicit
and detailed as possible; length of time
observed in the mitigation zone, note
any observed changes in behavior);
Æ Distance from vessel to animal;
Æ Direction of animal’s travel relative
to the vessel;
Æ Platform activity at time of sighting
(i.e., transit, deployment, recovery); and
Æ Weather conditions (i.e., BSS,
cloud cover).
Æ During icebreaking, the following
information must be recorded:
Æ Start and end time of icebreaking;
and
Æ Ice cover conditions.
• During deployment and recovery of
acoustic sources or UUVs, visual
observation must begin 30 minutes prior
to deployment or recovery and continue
through 30 minutes following the source
deployment or recovery.
• The ONR must submit its draft
report(s) on all monitoring conducted
under the IHA within 90 calendar days
of the completion of monitoring or 60
calendar days prior to the requested
issuance of any subsequent IHA for
research activities at the same location,
whichever comes first. A final report
must be prepared and submitted within
30 calendar days following receipt of
any NMFS comments on the draft
report. If no comments are received
from NMFS within 30 calendar days of
receipt of the draft report, the report
shall be considered final.
• All draft and final monitoring
reports must be submitted to
PR.ITP.MonitoringReports@noaa.gov
and ITP.clevenstine@noaa.gov.
• The marine mammal report, at
minimum, must include:
Æ Dates and times (begin and end) of
all marine mammal monitoring;
Æ Acoustic source use or icebreaking;
Æ Watch stander location(s) during
marine mammal monitoring;
Æ Environmental conditions during
monitoring periods (at beginning and
end of watch standing shift and
whenever conditions change
significantly), including BSS and any
other relevant weather conditions
including cloud cover, fog, sun glare,
and overall visibility to the horizon, and
estimated observable distance;
Æ Upon observation of a marine
mammal, the following information:
D Name of watch stander who sighted
the animal(s), the watch stander
location, and activity at time of sighting;
D Time of sighting;
D Identification of the animal(s) (e.g.,
genus/species, lowest possible
taxonomic level, or unidentified), watch
stander confidence in identification,
and the composition of the group if
there is a mix of species;
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D Distance and location of each
observed marine mammal relative to the
acoustic source or icebreaking for each
sighting;
D Estimated number of animals (min/
max/best estimate);
D Estimated number of animals by
cohort (adults, juveniles, neonates,
group composition, etc.);
D Animal’s closest point of approach
and estimated time spent within the
harassment zone; and
D Description of any marine mammal
behavioral observations (e.g., observed
behaviors such as feeding or traveling),
including an assessment of behavioral
responses thought to have resulted from
the activity (e.g., no response or changes
in behavioral state such as ceasing
feeding, changing direction, flushing, or
breaching.
Æ Number of shutdowns during
monitoring, if any;
Æ Marine mammal sightings
(including the marine mammal’s
location (latitude/longitude));
Æ Number of individuals of each
species observed during source
deployment, operation, and recovery;
and
Æ Detailed information about
implementation of any mitigation (e.g.,
shutdowns, delays), a description of
specific actions that ensued, and
resulting changes in behavior of the
animal(s), if any.
• The ONR must submit all watch
stander data electronically in a format
that can be queried, such as a
spreadsheet or database (i.e., digital
images of data sheets are not sufficient).
• Reporting injured or dead marine
mammals:
Æ In the event that personnel
involved in the specified activities
discover an injured or dead marine
mammal, the ONR must report the
incident to the Office of Protected
Resources (OPR), NMFS
(PR.ITP.MonitoringReports@noaa.gov
and ITP.clevenstine@noaa.gov) and to
the Alaska regional stranding network
(877–925–7773) as soon as feasible. If
the death or injury was clearly caused
by the specified activity, the ONR must
immediately cease the activities until
NMFS OPR is able to review the
circumstances of the incident and
determine what, if any, additional
measures are appropriate to ensure
compliance with the terms of this IHA.
The ONR must not resume their
activities until notified by NMFS.
Æ The report must include the
following information:
D Time, date, and location (latitude/
longitude) of the first discovery (and
updated location information if known
and applicable);
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D Species identification (if known) or
description of the animal(s) involved;
D Condition of the animal(s)
(including carcass condition if the
animal is dead);
D Observed behaviors of the animal(s),
if alive;
D If available, photographs or video
footage of the animal(s); and
D General circumstances under which
the animal was discovered.
• Vessel Strike: In the event of a
vessel strike of a marine mammal by any
vessel involved in the activities covered
by the authorization, the ONR shall
report the incident to OPR, NMFS and
to the Alaska regional stranding
coordinator (877–925–7773) as soon as
feasible. The report must include the
following information:
Æ Time, date, and location (latitude/
longitude) of the incident;
Æ Species identification (if known) or
description of the animal(s) involved;
Æ Vessel’s speed during and leading
up to the incident;
Æ Vessel’s course/heading and what
operations were being conducted (if
applicable);
Æ Status of all sound sources in use;
Æ Description of avoidance measures/
requirements that were in place at the
time of the strike and what additional
measures were taken, if any, to avoid
strike;
Æ Environmental conditions (e.g.,
wind speed and direction, BSS, cloud
cover, visibility) immediately preceding
the strike;
Æ Estimated size and length of animal
that was struck;
Æ Description of the behavior of the
marine mammal immediately preceding
and following the strike;
Æ If available, description of the
presence and behavior of any other
marine mammals immediately
preceding the strike;
Æ Estimated fate of the animal (e.g.,
dead, injured but alive, injured and
moving, blood or tissue observed in the
water, status unknown, disappeared);
and
Æ To the extent practicable,
photographs or video footage of the
animal(s).
Negligible Impact Analysis and
Determination
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
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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. In addition to
considering estimates of the number of
marine mammals that might be ‘‘taken’’
through harassment, NMFS considers
other factors, such as the likely nature
of any impacts or responses (e.g.,
intensity, duration), the context of any
impacts or responses (e.g., critical
reproductive time or location, foraging
impacts affecting energetics), 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 baseline (e.g., as
reflected in the regulatory status of the
species, population size and growth rate
where known, ongoing sources of
human-caused mortality, or ambient
noise levels).
To avoid repetition, the discussion of
our analysis applies to beluga whales
and ringed seals, given that the
anticipated effects of this activity on
these different marine mammal stocks
are expected to be similar. Where there
are meaningful differences between
species or stocks, or groups of species,
in anticipated individual responses to
activities, impact of expected take on
the population due to differences in
population status, or impacts on habitat,
they are described independently in the
analysis below.
Underwater acoustic transmissions
associated with the proposed ARA, as
outlined previously, have the potential
to result in Level B harassment of beluga
seals and ringed seals in the form of
behavioral disturbances. No serious
injury, mortality, or Level A harassment
are anticipated to result from these
described activities. Effects on
individual belugas or ringed seals taken
by Level B harassment could include
alteration of dive behavior and/or
foraging behavior, effects to breathing
rates, interference with or alteration of
vocalization, avoidance, and flight.
More severe behavioral responses are
not anticipated due to the localized,
intermittent use of active acoustic
sources. Exposure duration is likely to
be short-term and individuals will, most
likely, simply be temporarily displaced
by moving away from the acoustic
source. Exposures are, therefore,
unlikely to result in any significant
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realized decrease in fitness for affected
individuals or adverse impacts to stocks
as a whole.
Arctic ringed seals are listed as
threatened under the ESA. The primary
concern for Arctic ringed seals is the
ongoing and anticipated loss of sea ice
and snow cover resulting from climate
change, which is expected to pose a
significant threat to ringed seals in the
future (Muto et al., 2021). In addition,
Arctic ringed seals have also been
experiencing a UME since 2019
although the cause of the UME is
currently undetermined. As mentioned
earlier, no mortality or serious injury to
ringed seals is anticipated nor proposed
to be authorized. Due to the short-term
duration of expected exposures and
required mitigation measures to reduce
adverse impacts, we do not expect the
proposed ARA to compound or
exacerbate the impacts of the ongoing
UME.
A small portion of the Study Area
overlaps with ringed seal critical
habitat. Although this habitat contains
features necessary for ringed seal
formation and maintenance of
subnivean birth lairs, basking and
molting, and foraging, these features are
also available throughout the rest of the
designated critical habitat area. Any
potential limited displacement of ringed
seals from the proposed ARA study area
would not be expected to interfere with
their ability to access necessary habitat
features, given the availability of similar
necessary habitat features nearby.
The Study Area also overlaps with
beluga whale migratory and feeding
BIAs. Due to the small amount of
overlap between the BIAs and the
proposed ARA study area as well as the
low intensity and short-term duration of
acoustic sources and required mitigation
measures, we expect minimal impacts to
migrating or feeding belugas. Shutdown
zones are expected to avoid the
potential for Level A harassment of
belugas and ringed seals, and to
minimize the severity of any Level B
harassment. The requirements of trained
dedicated watch personnel and speed
restrictions will also reduce the
likelihood of any ship strikes to
migrating belugas.
In all, the proposed activities are
expected to have minimal adverse
effects on marine mammal habitat.
While the activities may cause some fish
to leave the area of disturbance,
temporarily impacting marine
mammals’ foraging opportunities, this
would encompass a relatively small area
of habitat leaving large areas of existing
fish and marine mammal foraging
habitat unaffected. As such, the impacts
to marine mammal habitat are not
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expected to impact the health or fitness
of any marine mammals.
In summary and as described above,
the following factors primarily support
our preliminary determination that the
impacts resulting from this activity are
not expected to adversely affect any of
the species or stocks through effects on
annual rates of recruitment or survival:
• No serious injury or mortality is
anticipated or authorized;
• Impacts would be limited to Level
B harassment only;
• Only temporary and relatively lowlevel behavioral disturbances are
expected to result from these proposed
activities; and
• Impacts to marine mammal prey or
habitat will be minimal and short term.
The anticipated and authorized take is
not expected to impact the reproduction
or survival of any individual marine
mammals, much less rates of
recruitment or survival. 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 proposed
activity will have a negligible impact on
all affected marine mammal species or
stocks.
Unmitigable Adverse Impact Analysis
and Determination
In order to issue an IHA, 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
Alaskan 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.
Subsistence hunting is important for
many Alaska Native communities. A
study of the North Slope villages of
Nuiqsut, Kaktovik, and Utqiaġvik
identified the primary resources used
for subsistence and the locations for
harvest (Stephen R. Braund &
Associates, 2010), including terrestrial
mammals, birds, fish, and marine
mammals (bowhead whale, ringed seal,
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bearded seal, and walrus). Ringed seals
and beluga whales are likely located
within the project area during this
proposed action, yet the proposed
action would not remove individuals
from the population nor behaviorally
disturb them in a manner that would
affect their behavior more than 100 km
farther inshore where subsistence
hunting occurs. The permitted sources
would be placed far outside of the range
for subsistence hunting. The closest
active acoustic source (fixed or drifting)
within the proposed project site that is
likely to cause Level B harassment is
approximately 204 km (110 nm) from
land. This ensures a significant standoff
distance from any subsistence hunting
area. The closest distance to subsistence
hunting (130 km (70 nm)) is well
beyond the largest distance from the
sound sources in use at which
behavioral harassment would be
expected to occur (20 km (10.8 nm))
described above. Furthermore, there is
no reason to believe that any behavioral
disturbance of beluga whales or ringed
seals that occurs far offshore (we do not
anticipate any Level A harassment)
would affect their subsequent behavior
in a manner that would interfere with
subsistence uses should those animals
later interact with hunters.
In addition, ONR has been
communicating with the Native
communities about the proposed action.
The ONR-sponsored chief scientist for
AMOS gave a briefing on ONR research
planned for 2024–2025 Alaska Eskimo
Whaling Commission (AEWC) meeting
on December 15, 2023 in Anchorage,
Alaska. No questions were asked from
the commissioners during the brief or in
subsequent weeks afterwards. The
AEWC consists of representatives from
11 whaling villages (Wainwright,
Utqiaġvik, Savoonga, Point Lay, Nuiqut,
Kivalina, Kaktovik, Wales, Point Hope,
Little Diomede, and Gambell). These
briefings have communicated the lack of
any effect on subsistence hunting due to
the distance of the sources from hunting
areas. ONR-supported scientists also
attend Arctic Waterways Safety
Committee (AWSC) and AEWC
meetings on a regular basis to discuss
past, present, and future research
activities. While no take is anticipated
to result during transit, points of contact
for at-sea communication will also be
established between vessel captains and
subsistence hunters to avoid any
conflict of ship transit with hunting
activity.
Based on the description of the
specified activity, distance of the study
area from subsistence hunting grounds,
the measures described to minimize
adverse effects on the availability of
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marine mammals for subsistence
purposes, and the proposed mitigation
and monitoring measures, NMFS has
preliminarily determined that there will
not be an unmitigable adverse impact on
subsistence uses from ONR’s proposed
activities.
Peer Review of the Monitoring Plan
The MMPA requires that monitoring
plans be independently peer reviewed
where the proposed activity may affect
the availability of a species or stock for
taking for subsistence uses (16 U.S.C.
1371(a)(5)(D)(ii)(III)). Given the factors
discussed above, NMFS has also
determined that the activity is not likely
to affect the availability of any marine
mammal species or stock for taking for
subsistence uses, and therefore, peer
review of the monitoring plan is not
warranted for this project.
Endangered Species Act
Section 7(a)(2) of the ESA of 1973 (16
U.S.C. 1531 et seq.) requires that each
Federal agency insure that any action it
authorizes, funds, or carries out is not
likely to jeopardize the continued
existence of any endangered or
threatened species or result in the
destruction or adverse modification of
designated critical habitat. To ensure
ESA compliance for the issuance of
IHAs, NMFS consults internally
whenever we propose to authorize take
for endangered or threatened species, in
this case with the Alaska Regional
Office (AKR).
NMFS is proposing to authorize take
of ringed seals, which are listed under
the ESA. The Permits and Conservation
Division has requested initiation of
section 7 consultation with the AKR for
the issuance of this IHA. NMFS will
conclude the ESA consultation prior to
reaching a determination regarding the
proposed issuance of the authorization.
Proposed Authorization
As a result of these preliminary
determinations, NMFS proposes to issue
an IHA to the ONR for conducting a
seventh year of ARA in the Beaufort and
Chukchi Seas from September 2024 to
September 2025, provided the
previously mentioned mitigation,
monitoring, and reporting requirements
are incorporated. A draft of the
proposed IHA can be found at: https://
www.fisheries.noaa.gov/national/
marine-mammal-protection/incidentaltake-authorizations-military-readinessactivities.
Request for Public Comments
We request comment on our analyses,
the proposed authorization, and any
other aspect of this notice of proposed
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IHA for the proposed ARA. We also
request comment on the potential
renewal of this proposed IHA as
described in the paragraph below.
Please include with your comments any
supporting data or literature citations to
help inform decisions on the request for
this IHA or a subsequent renewal IHA.
On a case-by-case basis, NMFS may
issue a one-time, 1-year renewal IHA
following notice to the public providing
an additional 15 days for public
comments when (1) up to another year
of identical or nearly identical activities
as described in the Description of
Proposed Activity section of this notice
is planned or (2) the activities as
described in the Description of
Proposed Activity section of this notice
would not be completed by the time the
IHA expires and a renewal would allow
for completion of the activities beyond
that described in the Dates and Duration
section of this notice, provided all of the
following conditions are met:
• A request for renewal is received no
later than 60 days prior to the needed
renewal IHA effective date (recognizing
that the renewal IHA expiration date
cannot extend beyond 1 year from
expiration of the initial IHA).
• The request for renewal must
include the following:
(1) An explanation that the activities
to be conducted under the requested
renewal IHA are identical to the
activities analyzed under the initial
IHA, are a subset of the activities, or
include changes so minor (e.g.,
reduction in pile size) that the changes
do not affect the previous analyses,
mitigation and monitoring
requirements, or take estimates (with
the exception of reducing the type or
amount of take).
(2) A preliminary monitoring report
showing the results of the required
monitoring to date and an explanation
showing that the monitoring results do
not indicate impacts of a scale or nature
not previously analyzed or authorized.
• Upon review of the request for
renewal, the status of the affected
species or stocks, and any other
pertinent information, NMFS
determines that there are no more than
minor changes in the activities, the
mitigation and monitoring measures
will remain the same and appropriate,
and the findings in the initial IHA
remain valid.
Dated: August 8, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources,
National Marine Fisheries Service.
[FR Doc. 2024–18130 Filed 8–13–24; 8:45 am]
BILLING CODE 3510–22–P
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Agencies
[Federal Register Volume 89, Number 157 (Wednesday, August 14, 2024)]
[Notices]
[Pages 66068-66091]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-18130]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XE173]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Office of Naval Research's
Arctic Research Activities in the Beaufort and Chukchi Seas (Year 7)
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
-----------------------------------------------------------------------
SUMMARY: NMFS has received a request from the Office of Naval Research
(ONR) for authorization to take marine mammals incidental to Arctic
Research Activities (ARA) in the Beaufort Sea and eastern Chukchi Sea.
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting
comments on its proposal to issue an incidental harassment
authorization (IHA) to incidentally take marine mammals during the
specified activities. NMFS is also requesting comments on a possible
one-time, 1-year renewal that could be issued under certain
circumstances and if all requirements are met, as described in Request
for Public Comments at the end of this notice. NMFS will consider
public comments prior to making any final decision on the issuance of
the requested MMPA authorization and agency responses will be
summarized in the final notice of our decision. The ONR's activities
are considered 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 13, 2024.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service and should be submitted via email to
[email protected]. Electronic copies of the application and
supporting documents, as well as a list of the references cited in this
document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities. In case of problems accessing these
documents, please call the contact listed below.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Alyssa Clevenstine, Office of
Protected Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
[[Page 66069]]
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) 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, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) 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 the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the monitoring and
reporting of the takings. The definitions of all applicable MMPA
statutory terms cited above are included in the relevant sections
below.
The 2004 NDAA (Pub. L. 108-136) removed the ``small numbers'' and
``specified geographical region'' limitations indicated above and
amended the definition of ``harassment'' as applied to a ``military
readiness activity.'' The activity for which incidental take of marine
mammals is being requested qualifies as a military readiness activity.
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 review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
In 2018, the U.S. Navy prepared an Overseas Environmental
Assessment (OEA) analyzing the project. Prior to issuing the IHA for
the first year of this project, NMFS reviewed the 2018 EA and the
public comments received, determined that a separate NEPA analysis was
not necessary, and subsequently adopted the document and issued a NMFS
Finding of No Significant Impact (FONSI) in support of the issuance of
an IHA (83 FR 48799, September 27, 2018).
In 2019, the Navy prepared a supplemental OEA. Prior to issuing the
IHA in 2019, NMFS reviewed the supplemental OEA and the public comments
received, determined that a separate NEPA analysis was not necessary,
and subsequently adopted the document and issued a NMFS FONSI in
support of the issuance of an IHA (84 FR 50007, September 24, 2019).
In 2020, the Navy submitted a request for a renewal of the 2019
IHA. Prior to issuing the renewal IHA, NMFS reviewed ONR's application
and determined that the proposed action was identical to that
considered in the previous IHA. Because no significantly new
circumstances or information relevant to any environmental concerns had
been identified, NMFS determined that the preparation of a new or
supplemental NEPA document was not necessary and relied on the
supplemental OEA and FONSI from 2019 when issuing the renewal IHA in
2020 (85 FR 41560, July 10, 2020).
In 2021, the Navy submitted a request for an IHA for incidental
take of marine mammals during continuation of ARA. NMFS reviewed the
Navy's OEA and determined it to be sufficient for taking into
consideration the direct, indirect, and cumulative effects to the human
environment resulting from continuation of the ARA. NMFS subsequently
adopted that OEA and signed a FONSI (86 FR 54931, October 5, 2021).
In 2022, the Navy submitted a request for an IHA for incidental
take of marine mammals during continuation of ARA and prepared an OEA
analyzing the project. Prior to issuing the IHA for the project, we
reviewed the 2022-2025 OEA and the public comments received, determined
that a separate NEPA analysis was not necessary, and subsequently
adopted the document and issued our own FONSI in support of the
issuance of an IHA (87 FR 57458, September 20, 2022).
In 2023, the ONR requested a renewal of the 2022 IHA for ongoing
ARA from September 2023 to September 2024, and the 2022 IHA monitoring
report. Prior to issuing the renewal IHA, NMFS reviewed ONR's
application and determined that the proposed action was identical to
that considered in the previous IHA. Because no significantly new
circumstances or information relevant to any environmental concerns
were identified, NMFS determined that the preparation of a new or
supplemental NEPA document was not necessary and relied on the
supplemental OEA and FONSI from 2022 when issuing the renewal IHA in
2023 (88 FR 65657, September 18, 2023).
Accordingly, NMFS preliminarily has determined to adopt the Navy's
OEA for ONR ARA in the Beaufort and Chukchi Seas 2022-2025, provided
our independent evaluation of the document finds that it includes
adequate information analyzing the effects on the human environment of
issuing the IHA. NMFS is a not cooperating agency on the U.S. Navy's
OEA.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Summary of Request
On March 29, 2024, NMFS received a request from the ONR for an IHA
to take marine mammals incidental to ARA in the Beaufort and Chukchi
Seas. Following NMFS' review of the application, the ONR submitted a
revised version on July 23, 2024. The application was deemed adequate
and complete on August 5, 2024. The ONR's request is for take of beluga
whales and ringed seals by Level B harassment only. Neither the ONR nor
NMFS expect serious injury or mortality to result from this activity
and, therefore, an IHA is appropriate.
This proposed IHA would cover the seventh year of a larger project
for which ONR obtained prior IHAs and renewal IHAs (83 FR 48799,
September 27, 2018; 84 FR 50007, September 24, 2019; 85 FR 53333,
August 28, 2020; 86 FR 54931, October 5, 2021; 87 FR 57458, September
20, 2022; 88 FR 65657, September 18, 2023). ONR has complied with all
the requirements (e.g., mitigation, monitoring, and reporting) of the
previous IHAs.
Description of Proposed Activity
Overview
The ONR proposes to conduct scientific experiments in support of
ARA using active acoustic sources within the Beaufort and Chukchi Seas.
Project activities involve acoustic testing and a multi-frequency
navigation system concept test using left-behind active acoustic
sources. The proposed experiments involve the deployment of moored,
drifting, and ice-tethered active acoustic sources from the Research
Vessel (R/V) Sikuliaq. Recovery of equipment may be from R/V Sikuliaq,
[[Page 66070]]
U.S. Coast Guard Cutter (CGC) HEALY, or another vessel, and icebreaking
may be required. Underwater sound from the active acoustic sources and
noise from icebreaking may result in Level B harassment of marine
mammals.
Dates and Duration
The proposed action would occur from September 2024 through
September 2025 and include up to two research cruises. Acoustic testing
would take place during the cruises, with the first cruise beginning
September 2, 2024, and a potential second cruise occurring in summer or
fall 2025, which may include up to 8 days of icebreaking activities.
Geographic Region
The proposed action would occur across the U.S. Exclusive Economic
Zone (EEZ) in the Beaufort and Chukchi Seas, partially in the high seas
north of Alaska, the Global Commons, and within a part of the Canadian
EEZ (in which the appropriate permits would be obtained by the Navy)
(figure 1). The proposed action would primarily occur in the Beaufort
Sea but the analysis considers the drifting of active sources on buoys
into the eastern portion of the Chukchi Sea. The closest point of the
study area to the Alaska coast is 204 kilometers (km; 110 nautical
miles (nm)). The proposed study area is approximately 639,267 square
kilometers (km\2\).
[[Page 66071]]
[GRAPHIC] [TIFF OMITTED] TN14AU24.000
Detailed Description of the Specified Activity
The ONR ARA Global Prediction Program supports two major projects:
Stratified Ocean Dynamics of the Arctic (SODA) and Arctic Mobile
Observing System (AMOS). The SODA and AMOS projects have been
previously discussed in association with previously issued IHAs (83 FR
40234, August 14, 2018; 84 FR 37240, July 31, 2019). However, only
activities relating to the AMOS project will occur during the period
covered by this proposed action.
The proposed action constitutes the development of a modified
system under the ONR AMOS involving very-low-, low-, and mid-frequency
(VLF, LF, MF) transmissions (35 Hertz (Hz), 900 Hz, and 10 kilohertz
(kHz), respectively). The AMOS project utilizes acoustic sources and
receivers to provide a means of performing under-ice navigation for
gliders and unmanned undersea vehicles (UUVs). This would allow for the
possibility of year-round scientific observations of the environment in
the Arctic. As an environment that is particularly affected by climate
change, year-round observations under a variety of ice conditions are
required to study the
[[Page 66072]]
effects of this changing environment for military readiness, as well as
the implications of environmental change to humans and animals. VLF
technology is important in extending the range of navigation systems
and has the potential to allow for development and use of navigational
systems that would not be heard by some marine mammal species and,
therefore, would be less impactful overall.
Up to six moorings (four fixed acoustic navigation sources
transmitting at 900 Hz, two fixed VLF sources transmitting at 35 Hz)
and two drifting ice gateway buoys (IGBs) would be configured with
active acoustic sources and would operate for a period of up to 1 year.
Four gliders with passive acoustics would be used to support drifting
IGBs. No UUV use is planned during the September 2024 research cruise;
however, there is the potential for one UUV (without active acoustic
sources) to be deployed and up to 8 days of icebreaking activities to
occur on a potential research cruise in summer/fall 2025, which would
require the use of a vessel with ice-breaking capabilities (e.g., CGC
HEALY).
During the research cruise, acoustic sources would be deployed from
the vessel for intermittent testing of the system components, which
would take place in the vicinity of the source locations (figure 1).
During this testing, 35 Hz, 900 Hz, 10 kHz, and acoustic modems would
be employed. The six fixed moorings would be anchored on the seabed and
held in the water column with subsurface buoys.
Autonomous vehicles would be able to navigate by receiving acoustic
signals from multiple locations and triangulating. This is needed for
vehicles that are under ice and cannot communicate with satellites.
Source transmits would be offset by 15 minutes from each other (i.e.,
sources would not be transmitting at the same time). All navigation
sources would be recovered. The purpose of the navigation sources is to
orient UUVs and gliders in situations when they are under ice and
cannot communicate with satellites.
The proposed action would utilize non-impulsive acoustic sources,
although not all sources will cause take of marine mammals (tables 1,
2). Marine mammal takes would arise from the operation of non-impulsive
active sources. Although not currently planned, icebreaking could occur
as part of this proposed action if a research vessel needs to return to
the study area before the end of the IHA period to ensure scientific
objectives are met. In this case, icebreaking could result in Level B
harassment.
Below are descriptions of the platforms and equipment that would be
deployed at different times during the proposed activity.
Research Vessels
The R/V Sikuliaq would perform the research cruise in September
2024 and conduct testing of acoustic sources during the cruise, as well
as leave sources behind to operate as a year-round navigation system
observation. The vessel to be used in a potential 2025 cruise is yet to
be determined but the most probable option would be the CGC HEALY.
The R/V Sikuliaq has a maximum speed of approximately 12 knots
(22.2 km per hour (km/hr)) with a cruising speed of 11 knots (20.4 km/
hr). The R/V Sikuliaq is not an icebreaking ship but an ice
strengthened ship. It would not be icebreaking and therefore acoustic
signatures of icebreaking for the R/V Sikuliaq are not relevant. CGC
HEALY travels at a maximum speed of 17 knots (31.5 km/hr) with a
cruising speed of 12 knots (22.2 km/hr) and a maximum speed of 3 knots
(5.6 km/hr) when traveling through 1.07 m (3.5 ft) of sea ice. While no
icebreaking cruise on the CGC HEALY is scheduled during the IHA period,
need may arise. Therefore, for the purposes of this IHA application, an
icebreaking cruise is considered.
The R/V Sikuliaq, CGC HEALY, or any other vessel operating a
research cruise associated with the Proposed Action may perform the
following activities during their research cruises:
Deployment of moored and/or ice-tethered passive sensors
(oceanographic measurement devices, acoustic receivers);
Deployment of moored and/or ice-tethered active acoustic
sources to transmit acoustic signals;
Deployment of UUVs;
Deployment of drifting buoys, with or without acoustic
sources; or,
Recovery of equipment.
Glider Surveys
Glider surveys are proposed for the research cruise. All gliders
would be recovered; some may be recovered during the cruise, but the
remainder would be recovered at a later date. Up to four gliders would
be deployed during the research cruise as part of on-ice operations
(one to two gliders would be associated with each on-ice station).
Long-endurance, autonomous sea gliders are intended for use in
extended missions in ice-covered waters. Gliders are buoyancy-driven,
equipped with satellite modems providing two-way communication, and are
capable of transiting to depths of up to 1,000 m (3,280 ft). Gliders
would collect data in the area of the shallow water sources and moored
sources, moving at a speed of 0.25 meters per second (m/s; 23
kilometers per day (km/day)). A combination of recent advances in sea
glider technology would provide full-year endurance. When operating in
ice-covered waters, gliders navigate by trilateration (the process of
determining location by measurement of distances, using the geometry of
circles, spheres or triangles) from moored acoustic sound sources (or
dead reckoning should navigation signals be unavailable); they do not
contain any active acoustic sources. Hibernating gliders would continue
to track their position, waking to reposition should they drift too far
from their target region. Gliders would measure temperature, salinity,
dissolved oxygen, rates of dissipation of temperature variance (and
vertical turbulent diffusivity), and multi-spectral down welling
irradiance.
Moored and Drifting Acoustic Sources
During the September 2024 cruise, active acoustic sources would be
lowered from the cruise vessel while stationary, deployed on gliders
and UUVs, or deployed on fixed AMOS and VLF moorings for intermittent
testing of the system components. The testing would take place in the
vicinity of the source locations in figure 1. During this testing, 35
Hz, 900 Hz, 10 kHz, and acoustic modems would be employed. No UUV use
is planned during the September 2024 research cruise but UUV use may be
included in future test plans covered by this IHA.
Up to four fixed acoustic navigation sources transmitting at 900 Hz
would remain in place for a year. These moorings would be anchored on
the seabed and held in the water column with subsurface buoys. All
sources would be deployed by shipboard winches, which would lower
sources and receivers in a controlled manner. Anchors would be steel
``wagon wheels'' typically used for this type of deployment. Two VLF
sources transmitting at 35 Hz would be deployed in a similar manner.
Two drifting IGBs would also be configured with active acoustic
sources.
[[Page 66073]]
Table 1--Characteristics of Modeled Acoustic Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
Signal strength (dB Pulse width/duty
Platform (total number deployed) Acoustic source Purpose/ function Frequency re 1 [mu]Pa at 1 m) cycle
--------------------------------------------------------------------------------------------------------------------------------------------------------
REMUS 600 UUV \a\ (up to 1)........ WHOI Micro-modem...... Acoustic 900-950 Hz............ NTE 180 dB by sys 5 pings/hour with 30
communications. design limits. sec pulse length.
REMUS 600 UUV \a\ (up to 1)........ UUV/WHOI Micro-modem.. Acoustic 8-14 kHz.............. NTE 185 dB by sys 10% average duty
communications. design limits. cycle, with 4 sec
pulse length.
IGB (drifting) (2)................. WHOI Micro-modem...... Acoustic 900-950 Hz............ NTE 180 dB by sys Transmit every 4
communications. design limits. hours, 30 sec pulse
length.
IGB (drifting) (2)................. WHOI Micro-modem...... Acoustic 8-14 kHz.............. NTE 185 dB by sys Typically receive
communications. design limits. only. Transmit is
very intermittent.
Mooring (6)........................ WHOI Micro-modem (4).. Acoustic Navigation.. 900-950 Hz............ NTE 180 dB by sys Transmit every 4
design limits. hours, 30 sec pulse
length.
Mooring (6)........................ VLF (2)............... Acoustic Navigation.. 35 Hz................. NTE 190 dB........... Up to 4 times per
day, 10 minutes
each.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: dB re 1 [mu]Pa at 1 m = decibels referenced to 1 microPascal at 1 meter; Hz = Hertz; IGB = Ice Gateway Buoy; kHz = kilohertz; NTE = not to exceed;
VLF = very low frequency; WHOI = Woods Hole Oceanographic Institution.
\a\ REMUS use is not anticipated during the September 2024 cruise but is included in case of future use during the proposed IHA period.
Activities Not Likely To Result in Take
The following activities have been determined to be unlikely to
result in take of marine mammals. These activities are described here
but they are not discussed further in this notice.
De minimis Sources--The ONR characterizes de minimis sources as
those with the following parameters: low source levels (SLs), narrow
beams, downward directed transmission, short pulse lengths, frequencies
outside known marine mammal hearing ranges, or some combination of
these factors (Navy, 2013). NMFS concurs with the ONR's determination
that the sources they have identified here as de minimis are unlikely
to result in take of marine mammals. The following are some of the
planned de minimis sources which would be used during the proposed
action: Woods Hole Oceanographic Institution (WHOI) micromodem,
Acoustic Doppler Current Profilers (ADCPs), ice profilers, and
additional sources below 160 decibels referenced to 1 microPascal (dB
re 1 [mu]Pa) used during towing operations. ADCPs may be used on
moorings. Ice-profilers measure ice properties and roughness. The ADCPs
and ice-profilers would all be above 200 kHz and therefore out of
marine mammal hearing ranges, with the exception of the 75 kHz ADCP
which has the characteristics and de minimis justification listed in
table 2. They may be employed on moorings or UUVs.
A WHOI micromodem will also be employed during the leave behind
period. In contrast with the WHOI micromodem usage described in table
1, which covers the use of the micromodem during research cruises, the
use of the source during the leave behind period differs in nature.
During this period, it is being used for very intermittent
communication with vehicles to communicate vehicle status for safety of
navigation purposes, and is treated as de minimis while employed in
this manner.
Table 2--Parameters for De Minimis Non-Impulsive Acoustic Sources
----------------------------------------------------------------------------------------------------------------
Sound pressure
Source name Frequency level (dB re 1 Pulse length Duty cycle De minimis
range (kHz) [mu]Pa at 1 m) (seconds) (percent) justification
----------------------------------------------------------------------------------------------------------------
ADCP.......................... >200, 150, or 190 <0.001 <0.1 Very low pulse
75 length, narrow
beam, moderate
source level.
Nortek Signature 500 kHz 500 214 <0.1 <13 Very high
Doppler Velocity Log. frequency.
CTD Attached Echosounder...... 5-20 160 0.004 2 Very low source
level.
----------------------------------------------------------------------------------------------------------------
Note: dB re 1 [mu]Pa at 1 m = decibels referenced to 1 microPascal at 1 meter; kHz = kilohertz; ADCP = acoustic
Doppler current profiler; CTD = conductivity temperature depth.
Drifting Oceanographic Sensors--Observations of ocean-ice
interactions require the use of sensors that are moored and embedded in
the ice. For the proposed action, it will not be required to break ice
to do this, as deployments can be performed in areas of low ice-
coverage or free floating ice. Sensors are deployed within a few dozen
meters of each other on the same ice floe. Three types of sensors would
be used: autonomous ocean flux buoys, Integrated Autonomous Drifters,
and ice-tethered profilers. The autonomous ocean flux buoys measure
oceanographic properties just below the ocean-ice interface. The
autonomous ocean flux buoys would have ADCPs and temperature chains
attached, to measure temperature, salinity, and other ocean parameters
the top 6 m (20 ft) of the water column. Integrated Autonomous Drifters
would have a long temperate string extending down to 200 m (656 ft)
depth and would incorporate meteorological sensors, and a temperature
spring to estimate ice thickness. The ice-tethered profilers would
collect information on ocean temperature, salinity, and velocity down
to 250 m (820 ft) depth.
Up to 20 Argo-type autonomous profiling floats may be deployed in
the central Beaufort Sea. Argo float drift at 1,500 m (4,921 ft) depth,
profiling from 2,000 m (6,562 ft) to the sea surface once every 10 days
to collect profiles of
[[Page 66074]]
temperature and salinity. Moored Oceanographic Sensors--Moored sensors
would capture a range of ice, ocean, and atmospheric conditions on a
year-round basis. These would be bottom anchored, sub-surface moorings
measuring velocity, temperature, and salinity in the upper 500 m (1,640
ft) of the water column. The moorings also collect high-resolution
acoustic measurements of the ice using the ice profilers described
above. Ice velocity and surface waves would be measured by 500 kHz
multibeam sonars from Nortek Signatures. The moored oceanographic
sensors described above use only de minimis sources and are therefore
not anticipated to have the potential for impacts on marine mammals or
their habitat. On-ice Measurements--On-ice measurement systems would be
used to collect weather data. These would include an Autonomous Weather
Station and an Ice Mass Balance Buoy. The Autonomous Weather Station
would be deployed on a tripod; the tripod has insulated foot platforms
that are frozen into the ice. The system would consist of an
anemometer, humidity sensor, and pressure sensor. The Autonomous
Weather Station also includes an altimeter that is de minimis due to
its very high frequency (200 kHz). The Ice Mass Balance Buoy is a 6 m
(20 ft) sensor string, which is deployed through a 5 centimeter (cm; 2
inch (in)) hole drilled into the ice. The string is weighted by a 1
kilogram (kg; 2.2 pound (lb)) lead weight and is supported by a tripod.
The buoy contains a de minimis 200 kHz altimeter and snow depth sensor.
Autonomous Weather Stations and Ice Mass Balance Buoys will be deployed
and will drift with the ice, making measurements until their host ice
floes melt, thus destroying the instruments (likely in summer, roughly
1 year after deployment). After the on-ice instruments are destroyed
they cannot be recovered and would sink to the seafloor as their host
ice floes melted.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
Table 3 lists all species or stocks for which take is expected and
proposed to be authorized for this activity and summarizes information
related to the population or stock, including regulatory status under
the MMPA and Endangered Species Act (ESA) and potential biological
removal (PBR), where known. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is anticipated or proposed
to be authorized here, PBR and annual serious injury and mortality from
anthropogenic sources are included here as gross indicators of the
status of the species or stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Alaska SARs (Young et al., 2023). All values presented in
table 3 are the most recent available at the time of publication and
are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.
Table 3--Species Likely Impacted by the Specified Activities \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\2\ abundance survey) \3\ SI \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Beluga Whale........................ Delphinapterus leucas.. Beaufort Sea........... -, -, N 39,258 (0.229, N/A, UND 104
1992).
Beluga Whale........................ Delphinapterus leucas.. Eastern Chukchi........ -, -, N 13,305 (0.51, 8,875, 178 56
2017).
Ringed Seal......................... Pusa hispida........... Arctic................. T, D, Y UND \5\ (UND, UND, UND 6,459
2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/).
\2\ 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 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.
\3\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, vessel strike). Annual 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.
\5\ A reliable population estimate for the entire stock is not available. Using a sub-sample of data collected from the U.S. portion of the Bering Sea,
an abundance estimate of 171,418 ringed seals has been calculated, but this estimate does not account for availability bias due to seals in the water
or in the shore-fast ice zone at the time of the survey. The actual number of ringed seals in the U.S. portion of the Bering Sea is likely much
higher. Using the Nmin based upon this negatively biased population estimate, the PBR is calculated to be 4,755 seals, although this is also a
negatively biased estimate.
As indicated above, both species (with three managed stocks) in
table 3 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. While bowhead whales
(Balaena mysticetus), gray whales (Eschrichtius robustus), bearded
seals (Erignathus barbatus), spotted seals (Phoca largha), and ribbon
seals (Histriophoca fasciata) have been documented in the area, the
temporal and/or spatial occurrence of these
[[Page 66075]]
species is such that take is not expected to occur, and they are not
discussed further beyond the explanation provided below.
Due to the location of the study area (i.e., northern offshore,
deep water), there were no calculated exposures for the bowhead whale,
gray whale, bearded seal, spotted seal, and ribbon seal from
quantitative modeling of acoustic sources. Bowhead and gray whales are
closely associated with the shallow waters of the continental shelf in
the Beaufort Sea and are unlikely to be exposed to acoustic harassment
from this activity (Young et al., 2023). Gray whales feed primarily in
the Beaufort Sea, Chukchi Sea, and Northwestern Bering Sea during the
summer and fall, but migrate south to winter in Baja California lagoons
(Young et al., 2023). Gray whales are primarily bottom feeders (Swartz
et al., 2006) in water depths of less than 60 m (196.9 ft) (Pike,
1962). Therefore, on the rare occasion that a gray whale does
overwinter in the Beaufort Sea (Stafford et al., 2007), we would expect
an overwintering individual to remain in shallow water over the
continental shelf where it could feed. Spotted seals tend to prefer
pack ice areas with water depths less than 200 m (656.2 ft) during the
spring and move to coastal habitats in the summer and fall, found as
far north as 69-72 degrees N (Muto et al., 2021). Although the study
area includes some waters south of 72 degrees N, the acoustic sources
with the potential to result in take of marine mammals are not found
below that latitude and spotted seals are not expected to be exposed.
Ribbon seals are found year-round in the Bering Sea but may seasonally
range into the Chukchi Sea (Muto et al., 2021). The proposed action
occurs primarily in the Beaufort Sea, outside of the core range of
ribbon seals, thus ribbon seals are not expected to be behaviorally
harassed. Narwhals (Monodon monoceros) are considered extralimital in
the project area and are not expected to be encountered. As no
harassment is expected of the bowhead whale, gray whale, spotted seal,
bearded seal, ribbon seal, and narwhal, these species will not be
discussed further in this proposed notice.
The ONR utilized Conn et al. (2014) in their IHA application as an
abundance estimate for ringed seals, which is based upon aerial
abundance and distribution surveys conducted in the U.S. portion Bering
Sea in 2012 (171,418 ringed seals) (Muto et al., 2021). This value is
likely an underestimate due to the lack of accounting for availability
bias for seals that were in the water at the time of the surveys as
well as not including seals located within the shore-fast ice zone
(Muto et al., 2021). Muto et al. (2021) notes that an accurate
population estimate is likely larger by a factor of two or more.
However, no accepted population estimate is present for Arctic ringed
seals. Therefore, NMFS will also adopt the Conn et al. (2014) abundance
estimate (171,418) for further analyses and discussions on this
proposed action by ONR.
In addition, the polar bear (Ursus maritimus) and Pacific walrus
(Odobenus rosmarus) may be found both on sea ice and/or in the water
within the Beaufort Sea and Chukchi Sea. These species are managed by
the U.S. Fish and Wildlife Service rather than NMFS and, therefore,
they are not considered further in this document.
Beluga Whale
Beluga whales are distributed throughout seasonally ice-covered
arctic and subarctic waters of the Northern Hemisphere (Gurevich,
1980), and are closely associated with open leads and polynyas in ice-
covered regions (Hazard, 1988). Belugas may be either migratory or
residential (non-migratory), depending on the population. Seasonal
distribution is affected by ice cover, tidal conditions, access to
prey, temperature, and human interaction (Frost et al., 1985; Hauser et
al., 2014).
There are five beluga whale stocks recognized within U.S. waters:
Cook Inlet, Bristol Bay, eastern Bering Sea, eastern Chukchi Sea, and
Beaufort Sea. Two stocks, the Beaufort Sea and eastern Chukchi Sea
stocks, have the potential to occur in the location of this proposed
action.
Migratory Biologically Important Areas (BIAs) for belugas in the
eastern Chukchi and Alaskan Beaufort Sea overlap the southern and
western portion of the Study Area (Clarke et al., 2023). A migration
corridor for both stocks of beluga whale includes the eastern Chukchi
Sea through the Beaufort Sea, with the Beaufort Sea stock utilizing the
migratory BIA in April-May and the Eastern Chukchi Sea stock utilizing
portions of the area in November. There are also feeding BIAs for both
stocks throughout the Arctic region (Clarke et al., 2023). During the
winter, they can be found foraging in offshore waters associated with
pack ice. When the sea ice melts in summer, they move to warmer river
estuaries and coastal areas for molting and calving (Muto et al.,
2021). Annual migrations can span over thousands of kilometers. The
residential Beaufort Sea populations participate in short distance
movements within their range throughout the year. Based on satellite
tags (Suydam et al., 2001; Hauser et al., 2014), there is some overlap
in distribution with the eastern Chukchi Sea beluga whale stock.
During the winter, eastern Chukchi Sea belugas occur in offshore
waters associated with pack ice. In the spring, they migrate to warmer
coastal estuaries, bays, and rivers where they may molt (Finley, 1982;
Suydam, 2009), give birth to, and care for their calves (Sergeant and
Brodie, 1969). Eastern Chukchi Sea belugas move into coastal areas,
including Kasegaluk Lagoon (outside of the proposed project site), in
late June and animals are sighted in the area until about mid-July
(Frost and Lowry, 1990; Frost et al., 1993). Satellite tags attached to
eastern Chukchi Sea belugas captured in Kasegaluk Lagoon during the
summer showed these whales traveled 1,100 km (593 nm) north of the
Alaska coastline, into the Canadian Beaufort Sea within three months
(Suydam et al., 2001). Satellite telemetry data from 23 whales tagged
during 1998-2007 suggest variation in movement patterns for different
age and/or sex classes during July-September (Suydam et al., 2005).
Adult males used deeper waters and remained there for the duration of
the summer; all belugas that moved into the Arctic Ocean (north of 75
degrees N) were males, and males traveled through 90 percent pack ice
cover to reach deeper waters in the Beaufort Sea and Arctic Ocean (79-
80 degrees N) by late July/early August. Adult and immature female
belugas remained at or near the shelf break in the south through the
eastern Bering Strait into the northern Bering Sea, remaining north of
Saint Lawrence Island over the winter.
Ringed Seal
Ringed seals are the most common pinniped in the Study Area and
have wide distribution in seasonally and permanently ice-covered waters
of the Northern Hemisphere (North Atlantic Marine Mammal Commission,
2004). Throughout their range, ringed seals have an affinity for ice-
covered waters and are well adapted to occupying both shore-fast and
pack ice (Kelly, 1988). Ringed seals can be found further offshore than
other pinnipeds since they can maintain breathing holes in ice
thickness greater than 2 m (6.6 ft) (Smith and Stirling, 1975). The
breathing holes are maintained by ringed seals using their sharp teeth
and claws found on their fore flippers. They remain in contact with ice
most of the year and use it as a platform for molting in late spring to
early summer, for pupping and nursing in late winter to
[[Page 66076]]
early spring, and for resting at other times of the year (Muto et al.,
2018).
Ringed seals have at least two distinct types of subnivean lairs:
Haulout lairs and birthing lairs (Smith and Stirling, 1975). Haul-out
lairs are typically single-chambered and offer protection from
predators and cold weather. Birthing lairs are larger, multi-chambered
areas that are used for pupping in addition to protection from
predators. Ringed seals pup on both shore-fast ice as well as stable
pack ice. Lentfer (1972) found that ringed seals north of
Utqia[gdot]vik, Alaska, build their subnivean lairs on the pack ice
near pressure ridges. Since subnivean lairs were found north of
Utqia[gdot]vik, Alaska, in pack ice, they are also assumed to be found
within the sea ice in the proposed project site. Ringed seals excavate
subnivean lairs in drifts over their breathing holes in the ice, in
which they rest, give birth, and nurse their pups for 5-9 weeks during
late winter and spring (Chapskii, 1940; McLaren, 1958; Smith and
Stirling, 1975). Ringed seals are born beginning in March but the
majority of births occur in early April. About a month after
parturition, mating begins in late April and early May.
In Alaskan waters, during winter and early spring when sea ice is
at its maximum extent, ringed seals are abundant in the northern Bering
Sea, Norton and Kotzebue Sounds, and throughout the Chukchi and
Beaufort seas (Frost, 1985; Kelly, 1988). Passive acoustic monitoring
of ringed seals from a high frequency recording package deployed at a
depth of 240 m (787 ft) in the Chukchi Sea 120 km (65 nm) north-
northwest of Utqia[gdot]vik, Alaska detected ringed seals in the area
between mid-December and late May over the 4 year study (Jones et al.,
2014). In addition, ringed seals have been observed near and beyond the
outer boundary of the U.S. EEZ (Beland and Ireland, 2010). During the
spring and early summer, ringed seals may migrate north as the ice edge
recedes and spend their summers in the open water period of the
northern Beaufort and Chukchi Seas (Frost, 1985). Foraging-type
movements have been recorded over the continental shelf and north of
the continental shelf waters (Von Duyke et al., 2020). During this
time, sub-adult ringed seals may also occur in the Arctic Ocean Basin
(Hamilton et al., 2015; Hamilton et al., 2017).
With the onset of fall freeze, ringed seal movements become
increasingly restricted and seals will either move west and south with
the advancing ice pack with many seals dispersing throughout the
Chukchi and Bering Seas, or remaining in the Beaufort Sea (Crawford et
al., 2012; Frost and Lowry, 1984; Harwood et al., 2012). Kelly et al.
(2010a) tracked home ranges for ringed seals in the subnivean period
(using shore-fast ice); the size of the home ranges varied from less
than 1 up to 279 km\2\ (median = 0.62 km\2\ for adult males, 0.65 km\2\
for adult females). Most (94 percent) of the home ranges were less than
3 km\2\ during the subnivean period (Kelly et al., 2010a). Near large
polynyas, ringed seals maintain ranges, up to 7,000 km\2\ during winter
and 2,100 km\2\ during spring (Born et al., 2004). Some adult ringed
seals return to the same small home ranges they occupied during the
previous winter (Kelly et al., 2010a). The size of winter home ranges
can vary by up to a factor of 10 depending on the amount of fast ice;
seal movements were more restricted during winters with extensive fast
ice, and were much less restricted where fast ice did not form at high
levels (Harwood et al., 2015).
Of the five recognized subspecies of ringed seals, the Arctic
ringed seal occurs in the Arctic Ocean and Bering Sea and is the only
stock that occurs in U.S. waters. NMFS listed the Arctic ringed seal
subspecies as threatened under the ESA on December 28, 2012 (77 FR
76706), primarily due to anticipated loss of sea ice through the end of
the 21st century. Climate change presents a major concern for the
conservation of ringed seals due to the potential for long-term habitat
loss and modification (Muto et al., 2021). Based upon an analysis of
various life history features and the rapid changes that may occur in
ringed seal habitat, ringed seals are expected to be highly sensitive
to climate change (Laidre et al., 2008; Kelly et al., 2010b).
Critical Habitat
Critical habitat for the ringed seal was designated in May 2022 and
includes marine waters within one specific area in the Bering, Chukchi,
and Beaufort Seas (87 FR 19232, April 1, 2022). Essential features
established by NMFS for conservation of ringed seals are (1) snow-
covered sea ice habitat suitable for the formation and maintenance of
subnivean birth lairs used for sheltering pups during whelping and
nursing, which is defined as waters 3 m (9.8 ft) or more in depth
(relative to Mean Lower Low Water (MLLW)) containing areas of seasonal
land-fast (shore-fast) ice or dense, stable pack ice, that have
undergone deformation and contain snowdrifts of sufficient depth to
form and maintain birth lairs (typically at least 54 cm (21.3 in)
deep); (2) sea ice habitat suitable as a platform for basking and
molting, which is defined as areas containing sea ice of 15 percent or
more concentration in waters 3 m (9.8 ft) or more in depth (relative to
MLLW); and (3) primary prey resources to support Arctic ringed seals,
which are defined to be small, often schooling, fishes, in particular
Arctic cod (Boreogadus saida), saffron cod (Eleginus gracilis), and
rainbow smelt (Osmerus dentex); and small crustaceans, in particular,
shrimps and amphipods.
The Study Area does not overlap with ringed seal critical habitat
(87 FR 19232, April 1, 2022). However, as stated in NMFS' final rule
for the Designation of Critical Habitat for the Arctic Subspecies of
the Ringed Seal (87 FR 19232, April 1, 2022), the area excluded from
the critical habitat contains one or more of the essential features of
the Arctic ringed seal's critical habitat, therefore, even though this
area is excluded from critical habitat designation, habitat with the
physical and biological features essential for ringed seal conservation
is still available to the species, although data are limited to inform
NMFS' assessment of the relative value of this area to the conservation
of the species. As described later and in more detail in the Potential
Effects of Specified Activities on Marine Mammals and Their Habitat
section, we expect minimal impacts to marine mammal habitat as a result
of the ONR's ARA, including impacts to ringed seal sea ice habitat
suitable as a platform for basking and molting and impacts on prey
availability.
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. 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) and Southall et al. (2019) recommended that marine mammals be
divided into hearing groups based on directly measured (behavioral or
auditory evoked potential techniques) or estimated hearing ranges
(behavioral response data, anatomical modeling, etc.). 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-
[[Page 66077]]
frequency cetaceans where the lower bound was deemed to be biologically
implausible and the lower bound from Southall et al. (2007) retained.
Marine mammal hearing groups and their associated hearing ranges are
provided in table 4.
Table 4--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans (dolphins, 150 Hz to 160 kHz.
toothed whales, beaked whales, bottlenose
whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus cruciger
& L. australis).
Phocid pinnipeds (PW) (underwater) (true 50 Hz to 86 kHz.
seals).
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 39 kHz.
lions and fur seals).
------------------------------------------------------------------------
\*\ Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on approximately 65 dB threshold from
normalized composite audiogram, with the exception for lower limits
for LF cetaceans (Southall et al., 2007) and PW pinniped
(approximation).
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 et al.,
2013). This division between phocid and otariid pinnipeds is now
reflected in the updated hearing groups proposed in Southall et al.
(2019).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take of Marine Mammals section, and the Proposed Mitigation
section, to draw conclusions regarding the likely impacts of these
activities on the reproductive success or survivorship of individuals
and whether those impacts are reasonably expected to, or reasonably
likely to, adversely affect the species or stock through effects on
annual rates of recruitment or survival.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (ANSI, 1995). The sound level of an area is
defined by the total acoustical energy being generated by known and
unknown sources. These sources may include physical (e.g., waves, wind,
precipitation, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activities may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
Active acoustic sources and icebreaking, if necessary, are proposed
for use in the Study Area. The sounds produced by these activities fall
into one of two general sound types: impulsive and non-impulsive.
Impulsive sounds (e.g., ice explosions, gunshots, sonic booms, impact
pile driving) are typically transient, brief (less than 1 second),
broadband, and consist of high peak sound pressure with rapid rise time
and rapid decay (ANSI, 1986; NIOSH, 1998; NMFS, 2018). Non-impulsive
sounds (e.g., aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, pile cutting, diamond wire sawing,
and active sonar systems) can be broadband, narrowband, or tonal, brief
or prolonged (continuous or intermittent), and typically do not have
the high peak sound pressure with raid rise/decay time that impulsive
sounds do (ANSI, 1986; NIOSH, 1998; NMFS, 2018). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997; Southall et al., 2007).
The likely or possible impacts of the ONR's proposed action on
marine mammals involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of vessels, equipment, and personnel (e.g., icebreaking
impacts, vessel and in-water vehicle strike, and bottom disturbance);
however, any impacts to marine mammals are expected to primarily be
acoustic in nature (e.g., non-impulsive acoustic sources, noise from
icebreaking vessel (``icebreaking noise''), and vessel noise).
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from active acoustic sources and noise from icebreaking is
the means by which marine mammals may be harassed from the ONR's
specified activity. In general, animals exposed to natural or
anthropogenic sound may experience behavioral, physiological, and/or
physical effects, ranging in magnitude from none to severe (Southall et
al., 2007). In general, exposure to pile driving noise has the
potential to result in behavioral reactions (e.g., avoidance, temporary
cessation of foraging and vocalizing, changes in dive behavior) and, in
limited cases, an auditory threshold shift (TS). Exposure to
anthropogenic noise can also lead to non-observable physiological
responses such an increase in stress hormones. Additional noise in a
marine mammal's habitat can mask acoustic cues used by marine mammals
to carry out daily functions such as communication and predator and
prey detection. The effects
[[Page 66078]]
of pile driving noise on marine mammals are dependent on several
factors, including, but not limited to, sound type (e.g., impulsive
versus non-impulsive), the species, age and sex class (e.g., adult male
versus mother with calf), duration of exposure, the distance between
the pile and the animal, received levels, behavior at time of exposure,
and previous history with exposure (Wartzok et al., 2004; Southall et
al., 2007). Here we discuss physical auditory effects (i.e., TS)
followed by behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced TS as a change, usually an increase,
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2018). The amount of TS is customarily expressed in dB and
TS can be permanent or temporary. As described in NMFS (2018), there
are numerous factors to consider when examining the consequence of TS,
including, but not limited to, the signal temporal pattern (e.g.,
impulsive or non-impulsive), likelihood an individual would be exposed
for a long enough duration or to a high enough level to induce a TS,
the magnitude of the TS, time to recovery (seconds to minutes or hours
to days), the frequency range of the exposure (i.e., spectral content),
the hearing and vocalization frequency range of the exposed species
relative to the signal's frequency spectrum (i.e., how animal uses
sound within the frequency band of the signal) (Kastelein et al.,
2014), and the overlap between the animal and the source (e.g.,
spatial, temporal, and spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). Available data
from humans and other terrestrial mammals indicate that a 40 dB TS
approximates PTS onset (see Ward et al., 1958; Ward et al., 1959; Ward,
1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; Henderson
et al., 2008). PTS levels for marine mammals are estimates as, with the
exception of a single study unintentionally inducing PTS in a harbor
seal (e.g., Kastak et al., 2008), there are no empirical data measuring
PTS in marine mammals largely due to the fact that, for various ethical
reasons, experiments involving anthropogenic noise exposure at levels
inducing PTS are not typically pursued or authorized (NMFS, 2018).
Temporary Threshold Shift (TTS)--TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2018). Based on data from cetacean TTS
measurements (see Southall et al., 2007), a TTS of 6 dB is considered
the minimum TS clearly larger than any day-to-day or session-to-session
variation in a subject's normal hearing ability (Finneran et al., 2000;
Schlundt et al., 2000; Finneran et al., 2002). As described in Finneran
(2016), marine mammal studies have shown the amount of TTS increases
with cumulative sound exposure level (SELcum) in an
accelerating fashion: At low exposures with lower SELcum,
the amount of TTS is typically small and the growth curves have shallow
slopes. At exposures with higher SELcum, the growth curves
become steeper and approach linear relationships with the noise SEL.
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 the
Auditory Masking section). 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 when the
animal is traveling through the open ocean, 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 time when communication is critical for successful mother/calf
interactions could have more serious impacts. We note that 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 cost.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran, 2015; Southall et al., 2019 for summaries). TTS
is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter et al., 1966). While experiencing TTS, the
hearing threshold rises, and a sound must be at a higher level in order
to be heard. In terrestrial and marine mammals, TTS can last from
minutes or hours to days (in cases of strong TTS). In many cases,
hearing sensitivity recovers rapidly after exposure to the sound ends.
For cetaceans, published data on the onset of TTS are limited to
captive bottlenose dolphin (Tursiops truncatus), beluga whale, harbor
porpoise (Phocoena phocoena), and Yangtze finless porpoise (Neophocoena
asiaeorientalis) (Southall et al., 2019). For pinnipeds in water,
measurements of TTS are limited to harbor seals (Phoca vitulina),
elephant seals (Mirounga angustirostris), bearded seals, and California
sea lions (Zalophus californianus) (Kastak et al., 1999; Kastak et al.,
2008; Kastelein et al., 2020b; Reichmuth et al., 2013; Sills et al.,
2020). TTS was not observed in spotted and ringed seals exposed to
single airgun impulse sounds at levels matching previous predictions of
TTS onset (Reichmuth et al., 2016). These studies examine hearing
thresholds measured in marine mammals before and after exposure to
intense or long-duration sound exposure. The difference between the
pre-exposure and post-exposure thresholds can be used to determine the
amount of threshold shift at various post-exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds at low frequencies, well below the region of best sensitivity
for a species or hearing group, are less hazardous than those at higher
frequencies, near the region of best sensitivity (Finneran and
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are
higher compared to those in the region of best sensitivity (i.e., a low
frequency noise would need to be louder to cause TTS onset when TTS
exposure level is higher), as shown for harbor porpoises and harbor
seals (Kastelein et al., 2019a; Kastelein et al., 2019b; Kastelein et
al., 2020a; Kastelein et al., 2020b). Note that in general, harbor
seals and harbor porpoises have a lower TTS onset than other measured
pinniped or cetacean species (Finneran, 2015). In addition, 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
(Mooney et al., 2009; Finneran et al., 2010; Kastelein et al., 2014;
Kastelein et al., 2015). This means that TTS predictions based on the
total SELcum will overestimate the amount of TTS from
intermittent exposures, such as sonars and impulsive sources.
Nachtigall et al. (2018) describe measurements of hearing sensitivity
of multiple odontocete species (bottlenose dolphin, harbor porpoise,
beluga whale, and false killer whale (Pseudorca crassidens)) when a
relatively loud sound was preceded by a warning
[[Page 66079]]
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). Data available on noise-induced hearing loss for
mysticetes are currently lacking (NMFS, 2018). Additionally, the
existing marine mammal TTS data come from a limited number of
individuals within these species.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals and there is no PTS data for cetaceans, but such
relationships are assumed to be similar to those in humans and other
terrestrial mammals. PTS typically occurs at exposure levels at least
several decibels above that inducing mild TTS (e.g., a 40-dB threshold
shift approximates PTS onset (Kryter et al., 1966; Miller, 1974), while
a 6-dB threshold shift approximates TTS onset (Southall et al., 2007;
Southall et al., 2019). Based on data from terrestrial mammals, a
precautionary assumption is that the PTS thresholds for impulsive
sounds (such as impact pile driving pulses as received close to the
source) are at least 6 dB higher than the TTS threshold on a peak-
pressure basis and PTS cumulative sound exposure level thresholds are
15 to 20 dB higher than TTS cumulative sound exposure level thresholds
(Southall et al., 2007; Southall et al., 2019). Given the higher level
of sound or longer exposure duration necessary to cause PTS as compared
with TTS, it is considerably less likely that PTS could occur.
Activities for this project include active acoustics, equipment
deployment and recovery, and, potentially, icebreaking. For the
proposed action, these activities would not occur at the same time and
there would likely be pauses in activities producing the sound during
each day. Given these pauses and that many marine mammals are likely
moving through the Study Area and not remaining for extended periods of
time, the potential for TS declines.
Behavioral Harassment--Exposure to noise from pile driving and
drilling also has the potential to behaviorally disturb marine mammals.
Generally speaking, NMFS considers a behavioral disturbance that rises
to the level of harassment under the MMPA a non-minor response--in
other words, not every response qualifies as behavioral disturbance,
and for responses that do, those of a higher level, or accrued across a
longer duration, have the potential to affect foraging, reproduction,
or survival. Behavioral disturbance may include a variety of effects,
including subtle changes in behavior (e.g., minor or brief avoidance of
an area or changes in vocalizations), more conspicuous changes in
similar behavioral activities, and more sustained and/or potentially
severe reactions, such as displacement from or abandonment of high-
quality habitat. Behavioral responses may include changing durations of
surfacing and dives, changing direction and/or speed; reducing/
increasing vocal activities; changing/cessation of certain behavioral
activities (such as socializing or feeding); eliciting a visible
startle response or aggressive behavior (such as tail/fin slapping or
jaw clapping); avoidance of areas where sound sources are located.
Pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound
are highly variable and context-specific and any reactions depend on
numerous intrinsic and extrinsic factors (e.g., species, state of
maturity, experience, current activity, reproductive state, auditory
sensitivity, time of day), as well as the interplay between factors
(e.g., Richardson et al., 1995; Wartzok et al., 2004; Southall et al.,
2007; Southall et al., 2019; Weilgart, 2007; Archer et al., 2010).
Behavioral reactions can vary not only among individuals but also
within an individual, depending on previous experience with a sound
source, context, and numerous other factors (Ellison et al., 2012), and
can vary depending on characteristics associated with the sound source
(e.g., whether it is moving or stationary, number of sources, distance
from the source). In general, pinnipeds seem more tolerant of, or at
least habituate more quickly to, potentially disturbing underwater
sound than do cetaceans, and generally seem to be less responsive to
exposure to industrial sound than most cetaceans. Please see Appendices
B and C of Southall et al. (2007) and Gomez et al. (2016) for reviews
of studies involving marine mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2004). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; Wartzok et al., 2004; NRC, 2005). Controlled experiments with
captive marine mammals have showed pronounced behavioral reactions,
including avoidance of loud sound sources (Ridgway et al., 1997;
Finneran et al., 2003). Observed responses of wild marine mammals to
loud pulsed sound sources (e.g., seismic airguns) have been varied but
often consist of avoidance behavior or other behavioral changes
(Richardson et al., 1995; Morton and Symonds, 2002; Nowacek et al.,
2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely and 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; Nowacek et al., 2004; Goldbogen et al., 2013a;
Goldbogen et al., 2013b). Variations in dive behavior may reflect
interruptions
[[Page 66080]]
in biologically significant activities (e.g., foraging) or they may be
of little biological significance. The impact of an alteration to dive
behavior 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.
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; Nowacek et al., 2004; Madsen et al., 2006; 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.
Variations in respiration naturally vary with different behaviors
and alterations to breathing 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. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, 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 (e.g., Kastelein et al., 2005; Kastelein et al., 2006).
For example, harbor porpoise' respiration rate increased in response to
pile driving sounds at and above a received broadband SPL of 136 dB
(zero-peak SPL: 151 dB re 1 [mu]Pa; SEL of a single strike: 127 dB re 1
[mu]Pa\2\-s) (Kastelein et al., 2013).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior 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 increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004),
respectively, while North Atlantic right whales (Eubalaena glacialis)
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). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
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, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). Avoidance may be short-
term, with animals returning to the area once the noise has ceased
(e.g., Bowles et al., 1994; Morton and Symonds, 2002). 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).
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; Bowers et al., 2018). 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, marine
mammal strandings (Evans and England, 2001). However, it should be
noted that response to a perceived predator does not necessarily invoke
flight (Ford and Reeves, 2008), and whether individuals are solitary or
in groups may influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fishes and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Purser and Radford, 2011; Fritz et al., 2002). In
addition, 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., Daan et
al., 1996; Bradshaw et al., 1998). However, Ridgway et al. (2006)
reported that increased vigilance in bottlenose dolphins exposed to
sound over a 5-day period did not cause any sleep deprivation or stress
effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than 1 day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive (i.e., meaningful) behavioral reactions and multi-day
anthropogenic activities. For example, just because an activity lasts
for multiple days does not necessarily mean that individual animals are
either exposed to activity-related stressors for multiple days or,
further, exposed in a manner resulting in sustained multi-day
substantive behavioral responses.
Behavioral Responses to Icebreaking Noise--Ringed seals on pack ice
showed various behaviors when approached by an icebreaking vessel. A
majority of seals dove underwater when the ship was within 0.93 km (0.5
nm) while others remained on the ice. However, as icebreaking vessels
came closer to the seals, most dove underwater. Ringed seals have also
been observed foraging in the wake of an icebreaking vessel (Richardson
et al., 1995) and may have preferentially established breathing holes
in the ship tracks after the ice-breaker moved through the area.
Previous observations and studies using icebreaking ships provide a
greater understanding in how seal behavior may be affected by a vessel
transiting through the area.
Adult ringed seals spend up to 20 percent of the time in subnivean
lairs during the winter season (Kelly et al.,
[[Page 66081]]
2010a). Ringed seal pups spend about 50 percent of their time in the
lair during the nursing period (Lydersen and Hammill, 1993). During the
warm season ringed seals haul out on the ice. In a study of ringed seal
haul out activity by Born et al. (2002), ringed seals spent 25-57
percent of their time hauled out in June, which is during their molting
season. Ringed seal lairs are typically used by individual seals
(haulout lairs) or by a mother with a pup (birthing lairs); large lairs
used by many seals for hauling out are rare (Smith and Stirling, 1975).
If the non-impulsive acoustic transmissions are heard and are perceived
as a threat, ringed seals within subnivean lairs could react to the
sound in a similar fashion to their reaction to other threats, such as
polar bears (their primary predators), although the type of sound would
be novel to them. Responses of ringed seals to a variety of human-
induced sounds (e.g., helicopter noise, snowmobiles, dogs, people, and
seismic activity) have been variable; some seals entered the water and
some seals remained in the lair. However, in all instances in which
observed seals departed lairs in response to noise disturbance, they
subsequently reoccupied the lair (Kelly et al., 1988).
Ringed seal mothers have a strong bond with their pups and may
physically move their pups from the birth lair to an alternate lair to
avoid predation, sometimes risking their lives to defend their pups
from potential predators. If a ringed seal mother perceives the
proposed acoustic sources as a threat, the network of multiple birth
and haulout lairs allows the mother and pup to move to a new lair
(Smith and Stirling, 1975; Smith and Hammill, 1981). The acoustic
sources from this proposed action are not likely to impede a ringed
seal from finding a breathing hole or lair, as captive seals have been
found to primarily use vision to locate breathing holes and no effect
to ringed seal vision would occur from the acoustic disturbance (Elsner
et al., 1989; Wartzok et al., 1992). It is anticipated that a ringed
seal would be able to relocate to a different breathing hole relatively
easily without impacting their normal behavior patterns.
Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Selye, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine 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, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the 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 functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also 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 vessel 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), however, distress is an unlikely result of the proposed project
based on observations of marine mammals during previous, similar
projects in the region.
Auditory Masking--Since many marine mammals rely on sound to find
prey, moderate social interactions, and facilitate mating (Tyack,
2008), noise from anthropogenic sound sources can interfere with these
functions, but only if the noise spectrum overlaps with the hearing
sensitivity of the receiving marine mammal (Southall et al., 2007;
Clark et al., 2009; Hatch et al., 2012). Chronic exposure to excessive,
though not high-intensity, noise could cause masking at particular
frequencies for marine mammals that utilize sound for vital biological
functions (Clark et al., 2009). Acoustic masking is when other noises
such as from human sources interfere 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, navigation)
(Richardson et al., 1995; Erbe et al., 2016). Therefore, under certain
circumstances, marine mammals whose acoustical sensors or environment
are being severely masked could also be impaired from maximizing their
performance fitness in survival and reproduction. 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 (Hotchkin and
Parks, 2013).
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 human-made, it may be considered
harassment when disrupting or altering critical behaviors. It is
important to distinguish TTS and PTS, which persist after the sound
exposure, from masking, which occurs during the sound exposure. Because
masking (without resulting in TS) is not associated with abnormal
physiological function, it is not considered a physiological effect,
but rather a potential behavioral effect
[[Page 66082]]
(though not necessarily one that would be associated with harassment).
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) 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, 2010; 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 (Hotchkin and Parks, 2013). 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).
Marine mammals at or near the proposed project site may be exposed
to anthropogenic noise which may be a source of masking. Vocalization
changes may result from a need to compete with an increase in
background noise and include increasing the source level, modifying the
frequency, increasing the call repetition rate of vocalizations, or
ceasing to vocalize in the presence of increased noise (Hotchkin and
Parks, 2013). For example, in response to loud noise, beluga whales may
shift the frequency of their echolocation clicks to prevent masking by
anthropogenic noise (Eickmeier and Vallarta, 2023).
Masking is more likely to occur in the presence of broadband,
relatively continuous noise sources such as vibratory pile driving.
Energy distribution of pile driving covers a broad frequency spectrum,
and sound from pile driving would be within the audible range of
pinnipeds and cetaceans present in the proposed action area. While
icebreaking during the ONR's proposed action may mask some acoustic
signals that are relevant to the daily behavior of marine mammals, the
short-term duration (up to 8 days) and limited areas affected make it
very unlikely that the fitness of individual marine mammals would be
impacted.
Potential Effects on Prey--The marine mammal species in the Study
Area feed on marine invertebrates and fish. Studies of sound energy
effects on invertebrates are few, and primarily identify behavioral
responses. It is expected that most marine invertebrates would not
sense the frequencies of the acoustic transmissions from the acoustic
sources associated with the proposed action. Although acoustic sources
used during the proposed action may briefly impact individuals,
intermittent exposures to non-impulsive acoustic sources are not
expected to impact survival, growth, recruitment, or reproduction of
widespread marine invertebrate populations.
The fish species residing in the study area include those that are
closely associated with the deep ocean habitat of the Beaufort Sea.
Nearly 250 marine fish species have been described in the Arctic,
excluding the larger parts of the sub-Arctic Bering, Barents, and
Norwegian Seas (Mecklenburg et al., 2011). However, only about 30 are
known to occur in the Arctic waters of the Beaufort Sea (Christiansen
and Reist, 2013). Although hearing capability data only exist for fewer
than 100 of the 32,000 named fish species, current data suggest that
most species of fish detect sounds from 50 to 100 Hz, with few fish
hearing sounds above 4 kHz (Popper, 2008). It is believed that most
fish have the best hearing sensitivity from 100 to 400 Hz (Popper,
2003). Fish species in the study area are expected to hear the low-
frequency sources associated with the proposed action, but most are not
expected to detect sound from the mid-frequency sources. Human
generated sound could alter the behavior of a fish in a manner than
would affect its way of living, such as where it tries to locate food
or how well it could find a mate. Behavioral responses to loud noise
could include a startle response, such as the fish swimming away from
the source, the fish ``freezing'' and staying in place, or scattering
(Popper, 2003). Misund (1997) found that fish ahead of a ship showed
avoidance reactions at ranges of 49-149 m (160-489 ft). Avoidance
behavior of vessels, vertically or horizontally in the water column,
has been reported for cod and herring, and was attributed to vessel
noise. While acoustic sources associated with the proposed action may
influence the behavior of some fish species, other fish species may be
equally unresponsive. Overall effects to fish from the proposed action
would be localized, temporary, and infrequent.
Effects to Physical and Foraging Habitat--Ringed seals haul out on
pack ice during the spring and summer to molt (Reeves et al., 2002;
Born et al., 2002). Additionally, some studies suggested that ringed
seals might preferentially establish breathing holes in ship tracks
after vessels move through the area (Alliston, 1980; Alliston, 1981).
The amount of ice habitat disturbed by activities is small relative to
the amount of overall habitat available and there will be no permanent
or longer-term loss or modification of physical ice habitat used by
ringed seals. Vessel movement would have minimal effect on physical
beluga habitat as beluga habitat is solely within the water column.
Furthermore, the deployed sources that would remain in use after the
vessels have left the survey area have low duty cycles and lower source
levels, and any impacts to the acoustic habitat of marine mammals would
be minimal.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through the IHA, which will inform NMFS'
consideration of the negligible impact determinations and impacts on
subsistence uses.
Harassment is the only type of take expected to result from these
activities. For this 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 the behavioral patterns are abandoned or significantly
altered (Level B harassment).
Authorized takes would be by Level B harassment only, in the form
of direct behavioral disturbances and/or TTS for individual marine
mammals resulting from exposure to active acoustic transmissions and
icebreaking. Based on the nature of the activity, Level A harassment is
neither anticipated nor proposed to be authorized.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds
[[Page 66083]]
above which NMFS believes the best available science indicates marine
mammals will be behaviorally harassed or incur some degree of permanent
hearing impairment; (2) the area or volume of water that will be
ensonified above these levels in a day; (3) the density or occurrence
of marine mammals within these ensonified areas; and, (4) the number of
days of activities. We note that while these factors can contribute to
a basic calculation to provide an initial prediction of potential
takes, additional information that can qualitatively inform take
estimates is also sometimes available (e.g., previous monitoring
results or average group size). Below, we describe the factors
considered here in more detail and present the proposed take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur PTS of some degree (equated to Level A
harassment). Thresholds have also been developed identifying the
received level of in-air sound above which exposed pinnipeds would
likely be behaviorally harassed.
Level B Harassment
Though significantly driven by received level, the onset of
behavioral disturbance from anthropogenic noise exposure is also
informed to varying degrees by other factors related to the source or
exposure context (e.g., frequency, predictability, duty cycle, duration
of the exposure, signal-to-noise ratio, distance to the source), the
environment (e.g., bathymetry, other noises in the area, predators in
the area), and the receiving animals (hearing, motivation, experience,
demography, life stage, depth) and can be difficult to predict (e.g.,
Southall et al., 2007; Southall et al., 2021; Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB re 1 [mu]Pa
for continuous (e.g., vibratory pile driving, drilling) and above RMS
SPL 160 dB re 1 [mu]Pa for non-explosive impulsive (e.g., seismic
airguns) or intermittent (e.g., scientific sonar) sources. Generally
speaking, Level B harassment estimates based on these behavioral
harassment thresholds are expected to include any likely takes by TTS
as, in most cases, the likelihood of TTS occurs at distances from the
source less than those at which behavioral harassment is likely. TTS of
a sufficient degree can manifest as behavioral harassment, as reduced
hearing sensitivity and the potential reduced opportunities to detect
important signals (conspecific communication, predators, prey) may
result in changes in behavior patterns that would not otherwise occur.
In this case, NMFS is proposing to adopt the ONR's approach to
estimating incidental take by Level B harassment from the active
acoustic sources for this action, which includes use of dose response
functions. The ONR's dose response functions were developed to estimate
take from sonar and similar transducers, but are not applicable to
icebreaking. Multi-year research efforts have conducted sonar exposure
studies for odontocetes and mysticetes (Miller et al., 2012; Sivle et
al., 2012). Several studies with captive animals have provided data
under controlled circumstances for odontocetes and pinnipeds (Houser et
al., 2013b; Houser et al., 2013a). Moretti et al. (2014) published a
beaked whale dose-response curve based on passive acoustic monitoring
of beaked whales during U.S. Navy training activity at Atlantic
Underwater Test and Evaluation Center during actual Anti-Submarine
Warfare exercises. This information necessitated the update of the
behavioral response criteria for the U.S. Navy's environmental
analyses.
Southall et al. (2007), and more recently (Southall et al., 2019),
synthesized data from many past behavioral studies and observations to
determine the likelihood of behavioral reactions at specific sound
levels. While in general, the louder the sound source the more intense
the behavioral response, it was clear that the proximity of a sound
source and the animal's experience, motivation, and conditioning were
also critical factors influencing the response (Southall et al., 2007;
Southall et al., 2019). After examining all of the available data, the
authors felt that the derivation of thresholds for behavioral response
based solely on exposure level was not supported because context of the
animal at the time of sound exposure was an important factor in
estimating response. Nonetheless, in some conditions, consistent
avoidance reactions were noted at higher sound levels depending on the
marine mammal species or group allowing conclusions to be drawn. Phocid
seals showed avoidance reactions at or below 190 dB re 1 [mu]Pa at 1 m;
thus, seals may actually receive levels adequate to produce TTS before
avoiding the source.
Odontocete behavioral criteria for non-impulsive sources were
updated based on controlled exposure studies for dolphins and sea
mammals, sonar, and safety (3S) studies where odontocete behavioral
responses were reported after exposure to sonar (Miller et al., 2011;
Miller et al., 2012; Antunes et al., 2014; Miller et al., 2014; Houser
et al., 2013b). For the 3S study, the sonar outputs included 1-2 kHz
up- and down-sweeps and 6-7 kHz up-sweeps; source levels were ramped up
from 152-158 dB re 1 [mu]Pa to a maximum of 198-214 re 1 [mu]Pa at 1 m.
Sonar signals were ramped up over several pings while the vessel
approached the mammals. The study did include some control passes of
ships with the sonar off to discern the behavioral responses of the
mammals to vessel presence alone versus active sonar.
The controlled exposure studies included exposing the Navy's
trained bottlenose dolphins to mid-frequency sonar while they were in a
pen. Mid-frequency sonar was played at six different exposure levels
from 125-185 dB re 1 [mu]Pa (RMS). The behavioral response function for
odontocetes resulting from the studies described above has a 50 percent
probability of response at 157 dB re 1 [mu]Pa. Additionally, distance
cutoffs (20 km for MF cetaceans) were applied to exclude exposures
beyond which the potential of significant behavioral responses is
considered to be unlikely.
The pinniped behavioral threshold was updated based on controlled
exposure experiments on the following captive animals: hooded seal
(Cystophora cristata), gray seal (Halichoerus grypus), and California
sea lion (G[ouml]tz et al., 2010; Houser et al., 2013a; Kvadsheim et
al., 2010). Hooded seals were exposed to increasing levels of sonar
until an avoidance response was observed, while the grey seals were
exposed first to a single received level multiple times, then an
increasing received level. Each individual California sea lion was
exposed to the same received level ten times. These exposure sessions
were combined into a single response value, with an overall response
assumed if an animal responded in any single session. The resulting
behavioral response function for pinnipeds has a 50 percent probability
of response at 166 dB re 1
[[Page 66084]]
[mu]Pa. Additionally, distance cutoffs (10 km for pinnipeds) were
applied to exclude exposures beyond which the potential of significant
behavioral responses is considered unlikely. For additional information
regarding marine mammal thresholds for PTS and TTS onset, please see
NMFS (2018) and table 6.
Empirical evidence has not shown responses to non-impulsive
acoustic sources that would constitute take beyond a few km from a non-
impulsive acoustic source, which is why NMFS and the Navy
conservatively set distance cutoffs for pinnipeds and mid-frequency
cetaceans (U.S. Department of the Navy, 2017a). The cutoff distances
for fixed sources are different from those for moving sources, as they
are treated as individual sources in ONR's modeling given that the
distance between them is significantly greater than the range to which
environmental effects can occur. Fixed source cutoff distances used
were 5 km (2.7 nm) for pinnipeds and 10 km (5.4 nm) for beluga whales
(table 5). As some of the on-site drifting sources could come closer
together, the drifting source cutoffs applied were 10 km (5.4 nm) for
pinnipeds and 20 km (10.8 nm) for beluga whales (table 5). Regardless
of the received level at that distance, take is not estimated to occur
beyond these cutoff distances. Range to thresholds were calculated for
the noise associated with icebreaking in the study area. These all fall
within the same cutoff distances as non-impulsive acoustic sources;
range to behavioral threshold for both beluga whales and ringed seal
were under 5 km (2.7 nm), and range to TTS threshold for both under 15
m (49.2 ft) (table 5).
Table 5--Cutoff Distances and Acoustic Thresholds Identifying the Onset of Behavioral Disturbance, TTS, and PTS for Non-Impulsive Sound Sources
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fixed source Drifting source Behavioral Icebreaking source Behavioral
behavioral behavioral criteria: Non- behavioral criteria: Physiological Physiological
Hearing group Species threshold cutoff threshold cutoff impulsive acoustic threshold cutoff icebreaking criteria: onset criteria: onset
distance \a\ distance \a\ sources distance \a b\ sources TTS PTS
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-frequency cetaceans......... Beluga whale...... 10 km (5.4 nm).... 20 km (10.8 nm)... Mid-frequency BRF 5 km (2.7 nm)..... 120 dB re 1 178 dB SELcum..... 198 dB SELcum.
dose-response [micro]Pa step
function *. function.
Phocidae (in water)............. Ringed seal....... 5 km (2.7 nm)..... 10 km (5.4 nm).... Pinniped dose- 5 km (2.7 nm)..... 120 dB re 1 181 dB SELcum..... 201 dB SELcum.
response function [micro]Pa step
*. function.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: The threshold values provided are assumed for when the source is within the animal's best hearing sensitivity. The exact threshold varies based on the overlap of the source and the
frequency weighting (see figure 6-1 in IHA application).
\a\ Take is not estimated to occur beyond these cutoff distances, regardless of the received level.
\b\ Range to TTS threshold for both hearing groups for the noise associated with icebreaking in the Study Area is under 15 m (49.2 ft).
Level A Harassment
NMFS' Technical Guidance for Assessing the Effects of Anthropogenic
Sound on Marine Mammal Hearing (Version 2.0) (Technical Guidance, 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 ONR's proposed action includes the
use of non-impulsive (active sonar and icebreaking) sources; however,
Level A harassment is not expected as a result of the proposed
activities based on modeling, as described below, nor is it proposed to
be authorized by NMFS.
These thresholds are provided in the table below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, which may be accessed at:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 6--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has
a reference value of 1 [mu]Pa\2\s. In this table, thresholds are abbreviated to reflect American National
Standards Institute (ANSI) standards. However, peak sound pressure is defined by ANSI as incorporating
frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
[[Page 66085]]
Quantitative Modeling
The Navy performed a quantitative analysis to estimate the number
of marine mammals likely to be exposed to underwater acoustic
transmissions above the previously described threshold criteria during
the proposed action. Inputs to the quantitative analysis included
marine mammal density estimates obtained from the Kaschner et al.
(2006) habitat suitability model and (Ca[ntilde]adas et al., 2020),
marine mammal depth occurrence (U.S. Department of the Navy, 2017b),
oceanographic and mammal hearing data, and criteria and thresholds for
levels of potential effects. The quantitative analysis consists of
computer modeled estimates and a post-model analysis to determine the
number of potential animal exposures. The model calculates sound energy
propagation from the proposed non-impulsive acoustic sources, the sound
received by animat (virtual animal) dosimeters representing marine
mammals distributed in the area around the modeled activity, and
whether the sound received by animats exceeds the thresholds for
effects.
The Navy developed a set of software tools and compiled data for
estimating acoustic effects on marine mammals without consideration of
behavioral avoidance or mitigation. These tools and data sets serve as
integral components of the Navy Acoustic Effects Model (NAEMO). In
NAEMO, animats are distributed non-uniformly based on species-specific
density, depth distribution, and group size information and animats
record energy received at their location in the water column. A fully
three-dimensional environment is used for calculating sound propagation
and animat exposure in NAEMO. Site-specific bathymetry, sound speed
profiles, wind speed, and bottom properties are incorporated into the
propagation modeling process. NAEMO calculates the likely propagation
for various levels of energy (sound or pressure) resulting from each
source used during the training event.
NAEMO then records the energy received by each animat within the
energy footprint of the event and calculates the number of animats
having received levels of energy exposures that fall within defined
impact thresholds. Predicted effects on the animats within a scenario
are then tallied and the highest order effect (based on severity of
criteria; e.g., PTS over TTS) predicted for a given animat is assumed.
Each scenario, or each 24-hour period for scenarios lasting greater
than 24 hours is independent of all others, and therefore, the same
individual marine mammal (as represented by an animat in the model
environment) could be impacted during each independent scenario or 24-
hour period. In few instances, although the activities themselves all
occur within the proposed study location, sound may propagate beyond
the boundary of the study area. Any exposures occurring outside the
boundary of the study area are counted as if they occurred within the
study area boundary. NAEMO provides the initial estimated impacts on
marine species with a static horizontal distribution (i.e., animats in
the model environment do not move horizontally).
There are limitations to the data used in the acoustic effects
model, and the results must be interpreted within this context. While
the best available data and appropriate input assumptions have been
used in the modeling, when there is a lack of definitive data to
support an aspect of the modeling, conservative modeling assumptions
have been chosen (i.e., assumptions that may result in an overestimate
of acoustic exposures):
Animats are modeled as being underwater, stationary, and
facing the source and therefore always predicted to receive the maximum
potential sound level at a given location (i.e., no porpoising or
pinnipeds' heads above water);
Animats do not move horizontally (but change their
position vertically within the water column), which may overestimate
physiological effects such as hearing loss, especially for slow moving
or stationary sound sources in the model;
Animats are stationary horizontally and therefore do not
avoid the sound source, unlike in the wild where animals would most
often avoid exposures at higher sound levels, especially those
exposures that may result in PTS;
Multiple exposures within any 24-hour period are
considered one continuous exposure for the purposes of calculating
potential threshold shift, because there are not sufficient data to
estimate a hearing recovery function for the time between exposures;
and
Mitigation measures were not considered in the model. In
reality, sound-producing activities would be reduced, stopped, or
delayed if marine mammals are detected by visual monitoring.
Due to these inherent model limitations and simplifications, model-
estimated results should be further analyzed, considering such factors
as the range to specific effects, avoidance, and the likelihood of
successfully implementing mitigation measures. This analysis uses a
number of factors in addition to the acoustic model results to predict
acoustic effects on marine mammals, as described below in the Marine
Mammal Occurrence and Take Estimation section.
The underwater radiated noise signature for icebreaking in the
central Arctic Ocean by CGC HEALY during different types of ice-cover
was characterized in Roth et al. (2013). The radiated noise signatures
were characterized for various fractions of ice cover. For modeling,
the 8/10 and 3/10 ice cover were used. Each modeled day of icebreaking
consisted of 16 hours of 8/10 ice cover and 8 hours of 3/10 ice cover.
The sound signature of the 5/10 icebreaking activities, which would
correspond to half-power icebreaking, was not reported in Roth et al.
(2013); therefore, the full-power signature was used as a conservative
proxy for the half-power signature. Icebreaking was modeled for 8 days
total. Since ice forecasting cannot be predicted more than a few weeks
in advance, it is unknown if icebreaking would be needed to deploy or
retrieve the sources after 1 year of transmitting. Therefore, the
potential for an icebreaking cruise on CGC HEALY was conservatively
analyzed within the ONR's request for an IHA. As the R/V Sikuliaq is
not capable of icebreaking, acoustic noise created by icebreaking is
only modeled for the CGC HEALY. Figures 5a and 5b in Roth et al. (2013)
depict the source spectrum level versus frequency for 8/10 and 3/10 ice
cover, respectively. The sound signature of each of the ice coverage
levels was broken into 1-octave bins (table 7). In the model, each bin
was included as a separate source on the modeled vessel. When these
independent sources go active concurrently, they simulate the sound
signature of CGC HEALY. The modeled source level summed across these
bins was 196.2 dB for the 8/10 signature and 189.3 dB for the 3/10 ice
signature. These source levels are a good approximation of the
icebreaker's observed source level (provided in figure 4b of Roth et
al. (2013). Each frequency and source level was modeled as an
independent source, and applied simultaneously to all of the animats
within NAEMO. Each second was summed across frequency to estimate
SPLRMS. Any animat exposed to sound levels greater than 120
dB was considered a take by Level B harassment. For PTS and TTS,
determinations, sound exposure levels were summed over the duration of
the
[[Page 66086]]
test and the transit to the deep water deployment area. The method of
quantitative modeling for icebreaking is considered to be a
conservative approach; therefore, the number of takes estimated for
icebreaking are likely an overestimate and would not be expected to
reach that level.
Table 7--Modeled Bins for 8/10 Ice Coverage (Full Power) and 3/10 Ice
Coverage (Quarter Power) Icebreaking on CGC HEALY
------------------------------------------------------------------------
8/10 source 3/10 source
Frequency (Hz) level (dB) level (dB)
------------------------------------------------------------------------
25............................................ 189 187
50............................................ 188 182
100........................................... 189 179
200........................................... 190 177
400........................................... 188 175
800........................................... 183 170
1,600......................................... 177 166
3,200......................................... 176 171
6,400......................................... 172 168
12,800........................................ 167 164
------------------------------------------------------------------------
Non-Impulsive Acoustic Analysis
Most likely, individuals affected by acoustic transmission would
move away from the sound source. Ringed seals may be temporarily
displaced from their subnivean lairs in the winter, but a pinniped
would have to be within 5 km (2.7 nm) of a moored source or within 10
km (5.4 nm) of a drifting source for any behavioral reaction. Any
effects experienced by individual pinnipeds are anticipated to be
short-term disturbance of normal behavior, or temporary displacement or
disruption of animals that may be near elements of the proposed action.
Of historical sightings registered in the Ocean Biodiversity
Information System Spatial Ecological Analysis of Megavertebrate
Populations (OBIS-SEAMAP database) (Halpin et al., 2009) in the ARA
Study Area, nearly all (99 percent) occurred in summer and fall
seasons. However, there is no documentation to prove that this is
because ringed seals would all move out of the Study Area during the
cold season, or if the lack of sightings is due to the harsh
environment and ringed seal behavior being prohibitive factors for cold
season surveying. OBIS-SEAMAP reports 542 animals sighted over 150
records in the ARA Study Area across all years and seasons. Taking the
average of 542 animals in 150 records aligns with survey data from
previous ARA cruises that show up to three ringed seals (or small,
unidentified pinnipeds assumed to be ringed seals) per day sighted in
the Study Area. To account for any unsighted animals, that number was
rounded up to 4. Assuming that four animals would be present in the
Study Area, a rough estimate of density can be calculated using the
overall Study Area size:
4 ringed seals / 48,725 km\2\ = 0.00008209 ringed seals/km\2\
The area of influence surrounding each moored source would be 78.5
km\2\, and the area of influence surrounding each drifting source would
be 314 km\2\. The total area of influence on any given day from non-
impulsive acoustic sources would be 942 km\2\. The number of ringed
seals that could be taken daily can be calculated:
0.00008209 ringed seals/km\2\ x 942 km\2\ = 0.077 ringed seals/day
To be conservative, the ONR has assumed that one ringed seal would
be exposed to acoustic transmissions above the threshold for Level B
harassment, and that each would be exposed each day of the proposed
action (365 days total). Unlike the NAEMO modeling approach used to
estimate ringed seal takes in previous ARA IHAs, the occurrence method
used in this ARA IHA request does not support the differentiation
between behavioral or TTS exposures. Therefore, all takes are
classified as Level B harassment and not further distinguished.
Modeling for all previous years of ARA activities did not result in any
estimated Level A harassment. NMFS has no reason to expect that the ARA
activities during the effective dates of this IHA would be more likely
to result in Level A harassment. Therefore, no Level A harassment is
anticipated due to the proposed action.
Marine Mammal Occurrence and Take Estimation
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information which
will inform the take calculations. We also describe how the marine
mammal occurrence information is synthesized to produce a quantitative
estimate of the take that is reasonably likely to occur and proposed
for authorization.
The beluga whale density numbers utilized for quantitative acoustic
modeling are from the Navy Marine Species Density Database (U.S.
Department of the Navy, 2014). Where available (i.e., June through 15
October over the continental shelf primarily), density estimates used
were from Duke density modeling based upon line-transect surveys
(Ca[ntilde]adas et al., 2020). The remaining seasons and geographic
area were based on the habitat-based modeling by Kaschner (2004) and
Kaschner et al. (2006). Density for beluga whales was not distinguished
by stock and varied throughout the project area geographically and
monthly; the range of densities in the Study Area is shown in table 8.
The density estimates for ringed seals are based on the habitat
suitability modeling by Kaschner (2004) and Kaschner et al. (2006) and
shown in table 8.
Table 8--Density Estimates of Impacted Species
------------------------------------------------------------------------
Common name Stock Density (animals/km\2\)
------------------------------------------------------------------------
Beluga whale................. Beaufort Sea.... 0.000506 to 0.5176
Beluga whale................. Eastern Chukchi 0.000506 to 0.5176
Sea.
Ringed seal.................. Arctic.......... 0.1108 to 0.3562
------------------------------------------------------------------------
Take of all species would occur by Level B harassment only. NAEMO
was previously used to produce a qualitative estimate of PTS, TTS, and
behavioral exposures for ringed seals. For this proposed action, a new
approach that utilizes sighting data from previous surveys conducted
within the Study Area was used to estimate Level B harassment
associated with non-impulsive acoustic sources (see section 6.4.3 of
the IHA application). NAEMO modeling is still used to provide estimated
takes of beluga whales associated with non-impulsive acoustic sources,
as well as provide take estimations associated with icebreaking for
both species. Table 9 shows the total number of requested takes by
Level B harassment that NMFS proposes to authorize for both beluga
whale stocks and the Arctic ringed seal stock based upon NAEMO modeled
results.
[[Page 66087]]
Density estimates for beluga whales are equal as estimates were not
distinguished by stock (Kaschner, 2004; Kaschner et al., 2006). The
ranges of the Beaufort Sea and Eastern Chukchi Sea beluga whales vary
within the study area throughout the year (Hauser et al., 2014). Based
upon the limited information available regarding the expected spatial
distributions of each stock within the study area, take has been
apportioned equally to each stock (table 9). In addition, in NAEMO,
animats do not move horizontally or react in any way to avoid sound,
therefore, the current model may overestimate non-impulsive acoustic
impacts.
Table 9--Proposed Take by Level B Harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Active Icebreaking Icebreaking Total proposed Percentage of
Species Stock acoustics (behavioral) (TTS) take SAR abundance population
--------------------------------------------------------------------------------------------------------------------------------------------------------
Beluga whale...................... Beaufort Sea........ \a\ 177 \a\ 21 0 99 39,258 <1
Beluga whale...................... Chukchi Sea......... \a\ 177 \a\ 21 0 99 13,305 <1
Ringed seal....................... Arctic.............. 365 538 1 904 \b\ UND (171, <1
418)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Acoustic and icebreaking exposures to beluga whales were not modeled at the stock level as the density value is not distinguished by stock in the
Arctic for beluga whales (U.S. Department of the Navy, 2014). Estimated take of beluga whales due to active acoustics is 177 and 21 due to icebreaking
activities, totaling 198 takes of beluga whales. The total take was evenly distributed among the two stocks.
\b\ A reliable population estimate for the entire Arctic stock of ringed seals is not available and NMFS SAR lists it as Undetermined (UND). Using a sub-
sample of data collected from the U.S. portion of the Bering Sea (Conn et al., 2014), an abundance estimate of 171,418 ringed seals has been
calculated but this estimate does not account for availability bias due to seals in the water or in the shore-fast ice zone at the time of the survey.
The actual number of ringed seals in the U.S. portion of the Bering Sea is likely much higher. Using the minimum population size (Nmin = 158,507)
based upon this negatively biased population estimate, the PBR is calculated to be 4,755 seals, although this is also a negatively biased estimate.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses. NMFS regulations require applicants for incidental
take authorizations to include information about the availability and
feasibility (economic and technological) of equipment, methods, and
manner of conducting the activity or other means of effecting the least
practicable adverse impact upon the affected species or stocks, and
their habitat (50 CFR 216.104(a)(11)). The 2004 NDAA amended the MMPA
as it relates to military readiness activities and the incidental take
authorization process such that ``least practicable impact'' shall
include consideration of personnel safety, practicality of
implementation, and impact on the effectiveness of the military
readiness activity.
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat, as
well as subsistence uses. This considers the nature of the potential
adverse impact being mitigated (likelihood, scope, range). It further
considers the likelihood that the measure will be effective if
implemented (probability of accomplishing the mitigating result if
implemented as planned), the likelihood of effective implementation
(probability implemented as planned), and;
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
The following measures are proposed for this IHA:
All vessels operated by or for the Navy must have
personnel assigned to stand watch at all times while underway. Watch
personnel must employ visual search techniques using binoculars. While
underway and while using active acoustic sources/towed in-water
devices, at least one person with access to binoculars is required to
be on watch at all times.
Vessel captains and vessel personnel must remain alert at
all times, proceed with extreme caution, and operate at a safe speed so
that the vessel can take proper and effective action to avoid any
collisions with marine mammals.
During moored and drifting acoustic source deployment and
recovery, ONR must implement a mitigation zone of 55 m (180 ft) around
the deployed source. Deployment and recovery must cease if a marine
mammal is visually deterred within the mitigation zone. Deployment and
recovery may recommence if any one of the following conditions are met:
[cir] The animal is observed exiting the mitigation zone;
[cir] The animal is thought to have exited the mitigation zone
based on a determination of its course, speed, and movement relative to
the sound source;
[cir] The mitigation zone has been clear from any additional
sightings for a period of 15 minutes for pinnipeds and 30 minutes for
cetaceans.
Vessels must avoid approaching marine mammals head-on and
must maneuver to maintain a mitigation zone of 457 m (500 yards) around
all observed cetaceans and 183 m (200 yards) around all other observed
marine mammals, provided it is safe to do so.
Activities must cease if a marine mammal species for which
take was not authorized, or a species for which authorization was
granted but the authorized number of takes have been met, is observed
approaching or within the mitigation zone (table 10). Activities must
not resume until the animal is confirmed to have left the area.
Vessel captains must maintain at-sea communication with
subsistence hunters to avoid conflict of vessel transit with hunting
activity.
Table 10--Proposed Mitigation Zones
------------------------------------------------------------------------
Activity and/or effort type Species Mitigation zone
------------------------------------------------------------------------
Acoustic source deployment and Beluga whale...... 55 m (180 ft).
recovery, stationary.
[[Page 66088]]
Acoustic source deployment and Ringed seal....... 55 m (180 ft).
recovery, stationary.
Transit......................... Beluga whale...... 457 m (500 yards).
Transit......................... Ringed seal....... 183 m (200 yards).
------------------------------------------------------------------------
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, areas of similar significance,
and on the availability of such species or stock for subsistence uses.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that 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
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 while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
Mitigation and monitoring effectiveness.
The Navy has coordinated with NMFS to develop an overarching
program plan in which specific monitoring would occur. This plan is
called the Integrated Comprehensive Monitoring Program (ICMP) (U.S.
Department of the Navy, 2011). The ICMP has been developed in direct
response to Navy permitting requirements established through various
environmental compliance efforts. As a framework document, the ICMP
applies by regulation to those activities on ranges and operating areas
for which the Navy is seeking or has sought incidental take
authorizations. The ICMP is intended to coordinate monitoring efforts
across all regions and to allocate the most appropriate level and type
of effort based on a set of standardized research goals, and in
acknowledgement of regional scientific value and resource availability.
The ICMP is focused on Navy training and testing ranges where the
majority of Navy activities occur regularly as those areas have the
greatest potential for being impacted. ONR's ARA in comparison is a
less intensive test with little human activity present in the Arctic.
Human presence is limited to the deployment of sources that would take
place over several weeks. Additionally, due to the location and nature
of the testing, vessels and personnel would not be within the study
area for an extended period of time. As such, more extensive monitoring
requirements beyond the basic information being collected would not be
feasible as it would require additional personnel and equipment to
locate seals and a presence in the Arctic during a period of time other
then what is planned for source deployment. However, ONR will record
all observations of marine mammals, including the marine mammal's
species identification, location (latitude/longitude), behavior, and
distance from project activities. ONR will also record date and time of
sighting. This information is valuable in an area with few recorded
observations.
Marine mammal monitoring must be conducted in accordance with the
Navy's ICMP and the proposed IHA:
While underway, all vessels must have at least one person
trained through the U.S. Navy Marine Species Awareness Training Program
on watch during all activities;
Watch personnel must use standardized data collection
forms, whether hard copy or electronic. Watch personnel must
distinguish between sightings that occur during transit or during
deployment or recovery of acoustic sources. Data must be recorded on
all days of activities, even if marine mammals are not sighted;
At minimum, the following information must be recorded:
[cir] Vessel name;
[cir] Watch personnel names and affiliation;
[cir] Effort type (i.e., transit, deployment, recovery); and
[cir] Environmental conditions (at the beginning of watch stander
shift and whenever conditions change significantly), including Beaufort
Sea State (BSS) and any other relevant weather conditions, including
cloud cover, fog, sun glare, and overall visibility to the horizon.
Upon visual observation of any marine mammal, the
following information must be recorded:
[cir] Date/time of sighting;
[cir] Identification of animal (e.g., genus/species, lowest
possible taxonomic level, or unidentified) and the composition of the
group if there is a mix of species;
[cir] Location (latitude/longitude) of sighting;
[cir] Estimated number of animals (high/low/best);
[cir] Description (as many distinguishing features as possible of
each individual seen, including length, shape, color, pattern, scars or
markings, shape and size of dorsal fin, shape of head, and blow
characteristics);
[cir] Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping,
[[Page 66089]]
diving, feeding, traveling; as explicit and detailed as possible;
length of time observed in the mitigation zone, note any observed
changes in behavior);
[cir] Distance from vessel to animal;
[cir] Direction of animal's travel relative to the vessel;
[cir] Platform activity at time of sighting (i.e., transit,
deployment, recovery); and
[cir] Weather conditions (i.e., BSS, cloud cover).
[cir] During icebreaking, the following information must be
recorded:
[cir] Start and end time of icebreaking; and
[cir] Ice cover conditions.
During deployment and recovery of acoustic sources or
UUVs, visual observation must begin 30 minutes prior to deployment or
recovery and continue through 30 minutes following the source
deployment or recovery.
The ONR must submit its draft report(s) on all monitoring
conducted under the IHA within 90 calendar days of the completion of
monitoring or 60 calendar days prior to the requested issuance of any
subsequent IHA for research activities at the same location, whichever
comes first. A final report must be prepared and submitted within 30
calendar days following receipt of any NMFS comments on the draft
report. If no comments are received from NMFS within 30 calendar days
of receipt of the draft report, the report shall be considered final.
All draft and final monitoring reports must be submitted
to [email protected] and [email protected].
The marine mammal report, at minimum, must include:
[cir] Dates and times (begin and end) of all marine mammal
monitoring;
[cir] Acoustic source use or icebreaking;
[cir] Watch stander location(s) during marine mammal monitoring;
[cir] Environmental conditions during monitoring periods (at
beginning and end of watch standing shift and whenever conditions
change significantly), including BSS and any other relevant weather
conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
[cir] Upon observation of a marine mammal, the following
information:
[ssquf] Name of watch stander who sighted the animal(s), the watch
stander location, and activity at time of sighting;
[ssquf] Time of sighting;
[ssquf] Identification of the animal(s) (e.g., genus/species,
lowest possible taxonomic level, or unidentified), watch stander
confidence in identification, and the composition of the group if there
is a mix of species;
[ssquf] Distance and location of each observed marine mammal
relative to the acoustic source or icebreaking for each sighting;
[ssquf] Estimated number of animals (min/max/best estimate);
[ssquf] Estimated number of animals by cohort (adults, juveniles,
neonates, group composition, etc.);
[ssquf] Animal's closest point of approach and estimated time spent
within the harassment zone; and
[ssquf] Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses thought to have resulted from the
activity (e.g., no response or changes in behavioral state such as
ceasing feeding, changing direction, flushing, or breaching.
[cir] Number of shutdowns during monitoring, if any;
[cir] Marine mammal sightings (including the marine mammal's
location (latitude/longitude));
[cir] Number of individuals of each species observed during source
deployment, operation, and recovery; and
[cir] Detailed information about implementation of any mitigation
(e.g., shutdowns, delays), a description of specific actions that
ensued, and resulting changes in behavior of the animal(s), if any.
The ONR must submit all watch stander data electronically
in a format that can be queried, such as a spreadsheet or database
(i.e., digital images of data sheets are not sufficient).
Reporting injured or dead marine mammals:
[cir] In the event that personnel involved in the specified
activities discover an injured or dead marine mammal, the ONR must
report the incident to the Office of Protected Resources (OPR), NMFS
([email protected] and [email protected]) and to
the Alaska regional stranding network (877-925-7773) as soon as
feasible. If the death or injury was clearly caused by the specified
activity, the ONR must immediately cease the activities until NMFS OPR
is able to review the circumstances of the incident and determine what,
if any, additional measures are appropriate to ensure compliance with
the terms of this IHA. The ONR must not resume their activities until
notified by NMFS.
[cir] The report must include the following information:
[ssquf] Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
[ssquf] Species identification (if known) or description of the
animal(s) involved;
[ssquf] Condition of the animal(s) (including carcass condition if
the animal is dead);
[ssquf] Observed behaviors of the animal(s), if alive;
[ssquf] If available, photographs or video footage of the
animal(s); and
[ssquf] General circumstances under which the animal was
discovered.
Vessel Strike: In the event of a vessel strike of a marine
mammal by any vessel involved in the activities covered by the
authorization, the ONR shall report the incident to OPR, NMFS and to
the Alaska regional stranding coordinator (877-925-7773) as soon as
feasible. The report must include the following information:
[cir] Time, date, and location (latitude/longitude) of the
incident;
[cir] Species identification (if known) or description of the
animal(s) involved;
[cir] Vessel's speed during and leading up to the incident;
[cir] Vessel's course/heading and what operations were being
conducted (if applicable);
[cir] Status of all sound sources in use;
[cir] Description of avoidance measures/requirements that were in
place at the time of the strike and what additional measures were
taken, if any, to avoid strike;
[cir] Environmental conditions (e.g., wind speed and direction,
BSS, cloud cover, visibility) immediately preceding the strike;
[cir] Estimated size and length of animal that was struck;
[cir] Description of the behavior of the marine mammal immediately
preceding and following the strike;
[cir] If available, description of the presence and behavior of any
other marine mammals immediately preceding the strike;
[cir] Estimated fate of the animal (e.g., dead, injured but alive,
injured and moving, blood or tissue observed in the water, status
unknown, disappeared); and
[cir] To the extent practicable, photographs or video footage of
the animal(s).
Negligible Impact Analysis and Determination
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
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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. In addition to considering estimates of the
number of marine mammals that might be ``taken'' through harassment,
NMFS considers other factors, such as the likely nature of any impacts
or responses (e.g., intensity, duration), the context of any impacts or
responses (e.g., critical reproductive time or location, foraging
impacts affecting energetics), 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 baseline
(e.g., as reflected in the regulatory status of the species, population
size and growth rate where known, ongoing sources of human-caused
mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to
beluga whales and ringed seals, given that the anticipated effects of
this activity on these different marine mammal stocks are expected to
be similar. Where there are meaningful differences between species or
stocks, or groups of species, in anticipated individual responses to
activities, impact of expected take on the population due to
differences in population status, or impacts on habitat, they are
described independently in the analysis below.
Underwater acoustic transmissions associated with the proposed ARA,
as outlined previously, have the potential to result in Level B
harassment of beluga seals and ringed seals in the form of behavioral
disturbances. No serious injury, mortality, or Level A harassment are
anticipated to result from these described activities. Effects on
individual belugas or ringed seals taken by Level B harassment could
include alteration of dive behavior and/or foraging behavior, effects
to breathing rates, interference with or alteration of vocalization,
avoidance, and flight. More severe behavioral responses are not
anticipated due to the localized, intermittent use of active acoustic
sources. Exposure duration is likely to be short-term and individuals
will, most likely, simply be temporarily displaced by moving away from
the acoustic source. Exposures are, therefore, unlikely to result in
any significant realized decrease in fitness for affected individuals
or adverse impacts to stocks as a whole.
Arctic ringed seals are listed as threatened under the ESA. The
primary concern for Arctic ringed seals is the ongoing and anticipated
loss of sea ice and snow cover resulting from climate change, which is
expected to pose a significant threat to ringed seals in the future
(Muto et al., 2021). In addition, Arctic ringed seals have also been
experiencing a UME since 2019 although the cause of the UME is
currently undetermined. As mentioned earlier, no mortality or serious
injury to ringed seals is anticipated nor proposed to be authorized.
Due to the short-term duration of expected exposures and required
mitigation measures to reduce adverse impacts, we do not expect the
proposed ARA to compound or exacerbate the impacts of the ongoing UME.
A small portion of the Study Area overlaps with ringed seal
critical habitat. Although this habitat contains features necessary for
ringed seal formation and maintenance of subnivean birth lairs, basking
and molting, and foraging, these features are also available throughout
the rest of the designated critical habitat area. Any potential limited
displacement of ringed seals from the proposed ARA study area would not
be expected to interfere with their ability to access necessary habitat
features, given the availability of similar necessary habitat features
nearby.
The Study Area also overlaps with beluga whale migratory and
feeding BIAs. Due to the small amount of overlap between the BIAs and
the proposed ARA study area as well as the low intensity and short-term
duration of acoustic sources and required mitigation measures, we
expect minimal impacts to migrating or feeding belugas. Shutdown zones
are expected to avoid the potential for Level A harassment of belugas
and ringed seals, and to minimize the severity of any Level B
harassment. The requirements of trained dedicated watch personnel and
speed restrictions will also reduce the likelihood of any ship strikes
to migrating belugas.
In all, the proposed activities are expected to have minimal
adverse effects on marine mammal habitat. While the activities may
cause some fish to leave the area of disturbance, temporarily impacting
marine mammals' foraging opportunities, this would encompass a
relatively small area of habitat leaving large areas of existing fish
and marine mammal foraging habitat unaffected. As such, the impacts to
marine mammal habitat are not expected to impact the health or fitness
of any marine mammals.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect any of the species
or stocks through effects on annual rates of recruitment or survival:
No serious injury or mortality is anticipated or
authorized;
Impacts would be limited to Level B harassment only;
Only temporary and relatively low-level behavioral
disturbances are expected to result from these proposed activities; and
Impacts to marine mammal prey or habitat will be minimal
and short term.
The anticipated and authorized take is not expected to impact the
reproduction or survival of any individual marine mammals, much less
rates of recruitment or survival. 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 proposed
activity will have a negligible impact on all affected marine mammal
species or stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an IHA, 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
Alaskan 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.
Subsistence hunting is important for many Alaska Native
communities. A study of the North Slope villages of Nuiqsut, Kaktovik,
and Utqia[gdot]vik identified the primary resources used for
subsistence and the locations for harvest (Stephen R. Braund &
Associates, 2010), including terrestrial mammals, birds, fish, and
marine mammals (bowhead whale, ringed seal,
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bearded seal, and walrus). Ringed seals and beluga whales are likely
located within the project area during this proposed action, yet the
proposed action would not remove individuals from the population nor
behaviorally disturb them in a manner that would affect their behavior
more than 100 km farther inshore where subsistence hunting occurs. The
permitted sources would be placed far outside of the range for
subsistence hunting. The closest active acoustic source (fixed or
drifting) within the proposed project site that is likely to cause
Level B harassment is approximately 204 km (110 nm) from land. This
ensures a significant standoff distance from any subsistence hunting
area. The closest distance to subsistence hunting (130 km (70 nm)) is
well beyond the largest distance from the sound sources in use at which
behavioral harassment would be expected to occur (20 km (10.8 nm))
described above. Furthermore, there is no reason to believe that any
behavioral disturbance of beluga whales or ringed seals that occurs far
offshore (we do not anticipate any Level A harassment) would affect
their subsequent behavior in a manner that would interfere with
subsistence uses should those animals later interact with hunters.
In addition, ONR has been communicating with the Native communities
about the proposed action. The ONR-sponsored chief scientist for AMOS
gave a briefing on ONR research planned for 2024-2025 Alaska Eskimo
Whaling Commission (AEWC) meeting on December 15, 2023 in Anchorage,
Alaska. No questions were asked from the commissioners during the brief
or in subsequent weeks afterwards. The AEWC consists of representatives
from 11 whaling villages (Wainwright, Utqia[gdot]vik, Savoonga, Point
Lay, Nuiqut, Kivalina, Kaktovik, Wales, Point Hope, Little Diomede, and
Gambell). These briefings have communicated the lack of any effect on
subsistence hunting due to the distance of the sources from hunting
areas. ONR-supported scientists also attend Arctic Waterways Safety
Committee (AWSC) and AEWC meetings on a regular basis to discuss past,
present, and future research activities. While no take is anticipated
to result during transit, points of contact for at-sea communication
will also be established between vessel captains and subsistence
hunters to avoid any conflict of ship transit with hunting activity.
Based on the description of the specified activity, distance of the
study area from subsistence hunting grounds, the measures described to
minimize adverse effects on the availability of marine mammals for
subsistence purposes, and the proposed mitigation and monitoring
measures, NMFS has preliminarily determined that there will not be an
unmitigable adverse impact on subsistence uses from ONR's proposed
activities.
Peer Review of the Monitoring Plan
The MMPA requires that monitoring plans be independently peer
reviewed where the proposed activity may affect the availability of a
species or stock for taking for subsistence uses (16 U.S.C.
1371(a)(5)(D)(ii)(III)). Given the factors discussed above, NMFS has
also determined that the activity is not likely to affect the
availability of any marine mammal species or stock for taking for
subsistence uses, and therefore, peer review of the monitoring plan is
not warranted for this project.
Endangered Species Act
Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.)
requires that each Federal agency insure that any action it authorizes,
funds, or carries out is not likely to jeopardize the continued
existence of any endangered or threatened species or result in the
destruction or adverse modification of designated critical habitat. To
ensure ESA compliance for the issuance of IHAs, NMFS consults
internally whenever we propose to authorize take for endangered or
threatened species, in this case with the Alaska Regional Office (AKR).
NMFS is proposing to authorize take of ringed seals, which are
listed under the ESA. The Permits and Conservation Division has
requested initiation of section 7 consultation with the AKR for the
issuance of this IHA. NMFS will conclude the ESA consultation prior to
reaching a determination regarding the proposed issuance of the
authorization.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to the ONR for conducting a seventh year of ARA in the
Beaufort and Chukchi Seas from September 2024 to September 2025,
provided the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. A draft of the proposed IHA can be found
at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for the proposed ARA.
We also request comment on the potential renewal of this proposed IHA
as described in the paragraph below. Please include with your comments
any supporting data or literature citations to help inform decisions on
the request for this IHA or a subsequent renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of this notice is planned or (2) the activities as
described in the Description of Proposed Activity section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond 1 year from expiration
of the initial IHA).
The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: August 8, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2024-18130 Filed 8-13-24; 8:45 am]
BILLING CODE 3510-22-P