Taking and Importing Marine Mammals: Taking Marine Mammals Incidental to U.S. Navy Operations of Surveillance Towed Array Sensor System Low Frequency Active Sonar, 19460-19527 [2017-08066]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 82, Number 80 (Thursday, April 27, 2017)]
[Proposed Rules]
[Pages 19460-19527]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-08066]



[[Page 19459]]

Vol. 82

Thursday,

No. 80

April 27, 2017

Part II





Department of Commerce





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 National Oceanic and Atmospheric Administration





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50 CFR Part 218





Taking and Importing Marine Mammals: Taking Marine Mammals Incidental 
to U.S. Navy Operations of Surveillance Towed Array Sensor System Low 
Frequency Active Sonar; Proposed Rule

Federal Register / Vol. 82 , No. 80 / Thursday, April 27, 2017 / 
Proposed Rules

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 218

[Docket No. 160920860-7368-01]
RIN 0648-BG35


Taking and Importing Marine Mammals: Taking Marine Mammals 
Incidental to U.S. Navy Operations of Surveillance Towed Array Sensor 
System Low Frequency Active Sonar

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Proposed rule; request for comments.

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SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for 
authorization to take marine mammals, by harassment, incidental to 
conducting operations of Surveillance Towed Array Sensor System 
(SURTASS) Low Frequency Active (LFA) sonar in areas of the world's 
oceans (with the exception of Arctic and Antarctic waters and certain 
geographic restrictions), from August 15, 2017, through August 14, 
2022. The Navy's activities are considered military readiness 
activities pursuant to the Marine Mammal Protection Act (MMPA), as 
amended by the National Defense Authorization Act for Fiscal Year 2004 
(FY 2004 NDAA). Pursuant to the MMPA, NMFS is requesting comments on 
its proposal to issue regulations to govern the incidental take of 
marine mammals by Level B harassment during the specified activity.

DATES: Comments and information must be received no later than May 30, 
2017.

ADDRESSES: You may submit comments on this document, identified by 
NOAA-HQ-2017-0037, by either of the following methods:
    Electronic Submission: Submit all electronic public comments via 
the Federal e-Rulemaking Portal. Go to www.regulations.gov/#!docketDetail;D=NOAA-HQ-2017-0037, click the ``Comment Now!'' icon, 
complete the required fields, and enter or attach your comments.
    Mail: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
1315 East-West Highway, Silver Spring, MD 20910.
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, and may not consider 
comments received after the end of the comment period. Comments 
received electronically, including all attachments, must not exceed a 
25-megabyte file size. Attachments to electronic comments will be 
accepted in Microsoft Word, Excel, or Adobe PDF formats only. To help 
NMFS process and review comments more efficiently, please use only one 
method to submit comments. All comments received are a part of the 
public record and will generally be posted to www.regulations.gov and 
www.nmfs.noaa.gov/pr/permits/incidental/military without change. All 
Personal Identifying Information (for example, name, address, etc.) 
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: Dale Youngkin, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained by visiting the Internet at: 
www.nmfs.noaa.gov/pr/permits/incidental/military.htm. In case of 
problems accessing these documents, please call the contact listed 
above.

SUPPLEMENTARY INFORMATION:

Background

    Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1361 et seq.) directs 
the Secretary of Commerce (Secretary) to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals in a specified geographical region for a period of up to five 
years, provided that certain findings are made and the necessary 
prescriptions are established.
    The incidental taking of marine mammals shall be allowed if NMFS 
(through authority delegated by the Secretary) finds that the total 
taking by the specified activity during the specified time period will 
(1) have a negligible impact on the species or stock(s) and (2) not 
have an unmitigable adverse impact on the availability of the species 
or stock(s) for subsistence uses (where relevant). Further, the 
permissible methods of taking and other means of effecting the least 
practicable adverse impact on the species or stock and its habitat 
(i.e., mitigation) must be prescribed. Requirements pertaining to the 
monitoring and reporting of such taking must also be set forth.
    The allowance of incidental taking under section 101(a)(5)(A) 
requires promulgation of activity specific regulations. Subsequently, a 
Letter (or Letters) of Authorization (LOA) may be issued as governed by 
the regulations, provided that the level of taking will be consistent 
with the findings made for the total taking allowable under the 
specific regulations. The promulgation of regulations (with their 
associated prescribed mitigation, monitoring, and reporting) requires 
notice and opportunity for public comment.
    NMFS has defined ``Negligible impact'' in 50 CFR 216.103 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.
    The National Defense Authorization Act for Fiscal Year 2004 (FY 
2004 NDAA) (Pub. L. 108-136) removed the ``small numbers'' and 
``specified geographical region'' limitations indicated above and 
amended the definition of ``harassment'' as it applies to a ``military 
readiness activity'' to read as follows (Section 3(18)(B) of the MMPA): 
``(i) any act that injures or has the significant potential to injure a 
marine mammal or marine mammal stock in the wild'' (Level A 
Harassment); ``or (ii) any act that disturbs or is likely to disturb a 
marine mammal or marine mammal stock in the wild by causing disruption 
of natural behavioral patterns, including but not limited to migration, 
surfacing, nursing, breeding, feeding, or sheltering, to a point where 
such behavioral patterns are abandoned or significantly altered'' 
(Level B Harassment). In addition, the FY 2004 NDAA amended the MMPA as 
it relates to military readiness activities and the Incidental Take 
Authorization (ITA) process such that ``least practicable adverse 
impact'' shall include consideration of personnel safety, practicality 
of implementation, and impact on the effectiveness of the military 
readiness activity.

Summary of Request

    On August 26, 2016, NMFS received an application from the Navy 
requesting authorization for the take of individuals of 104 currently 
classified species or stocks of marine mammals (15 species of mysticete 
(baleen) whales, 60 species of odontocete (toothed) whales, and 29 
species of pinnipeds (seals and sea lions)), by harassment, incidental 
to the use of SURTASS LFA sonar on a maximum of four U.S. Naval ships 
for routine training, testing, and military operations, hereafter 
called activities, in various areas of the Pacific, Atlantic, and 
Indian Oceans and the Mediterranean Sea from August 15,

[[Page 19461]]

2017 through August 14, 2022. These activities are classified as 
military readiness activities. The Navy states, and NMFS concurs, that 
these military readiness activities may incidentally take marine 
mammals present within the Navy's operation areas by exposing them to 
SURTASS LFA sonar at levels that constitute Level B harassment as 
defined above. The Navy requests authorization to take individuals of 
the 104 currently classified species or stocks of marine mammals by 
Level B Harassment. This rule may also cover the authorization of 
additional associated stocks of marine mammals not listed here, should 
one or more of the stocks identified in this rule be formally separated 
into multiple stocks, provided NMFS is able to confirm the necessary 
findings for the newly identified stocks. As discussed later in this 
document, takes due to SURTASS LFA sonar will be limited to Level B 
behavioral harassment. No takes by Level A harassment will be 
authorized as Level A harassment will be avoided through the 
implementation of the Navy's proposed mitigation measures. In previous 
rulemakings, NMFS authorized small numbers of Level A takes out of an 
abundance of caution even though Level A takes were not anticipated. 
However, there have been no Level A takes resulting from the past 14 
years of SURTASS LFA sonar activities under previous rules. 
Additionally, the criteria and thresholds for assessing Level A 
harassment have been modified since prior rules. Under the new metrics, 
the potential for injury zone has been substantially reduced. 
Therefore, due to the small injury zones and the fact that mitigation 
measures would ensure that marine mammals would not receive levels 
associated with injury, the Navy has not requested authorization for 
Level A harassment takes, and NMFS is not proposing to authorize any 
takes by Level A harassment.
    This is NMFS' fourth rulemaking for SURTASS LFA sonar activities 
under the MMPA. NMFS' current five-year regulations governing 
incidental takings incidental to SURTASS LFA sonar activities and the 
related Letters of Authorizations (LOA) expire on August 15, 2017. NMFS 
published the first SURTASS LFA sonar rule on July 16, 2002 (67 FR 
46712), effective from August 2002 through August 2007. The second rule 
was published on August 21, 2007 (72 FR 46846), effective from August 
16, 2007, through August 15, 2012. The third rule was published on 
August 20, 2012 (77 FR 50290), and is effective through August 14, 
2017. For this proposed rulemaking, the Navy proposes to conduct the 
same types of sonar activities as they have conducted over the past 14 
years with the following exception: The Navy proposes to transmit a 
maximum number of 255 hours of LFA sonar per vessel per year, as 
opposed to the previously authorized 432 hours of LFA sonar per vessel 
per year. Based on historical operating parameters, the average duty 
cycle (i.e., the ratio of sound ``on'' time to total time) for SURTASS 
LFA sonar is normally 7.5 to 10 percent and the duty cycle is not 
expected to exceed 20 percent.

Description of the Specified Activities

Overview

    The proposed action is Navy's continued employment of up to four 
SURTASS LFA sonar systems in the world's non-polar oceans, which is 
classified as a military readiness activity, from August 2017 to August 
2022. Potential activities could occur in the Pacific, Atlantic, and 
Indian Oceans, and the Mediterranean Sea. The Navy will not operate 
SURTASS LFA sonar in Arctic and Antarctic waters. Additional geographic 
restrictions include maintaining SURTASS LFA sonar received levels 
below 180 dB re 1 [micro]Pa (root-mean-square (rms)) within 12 nautical 
miles (nmi) (22 kilometers (km)) of any land, and within the boundaries 
of designated Offshore Biologically Important Areas (OBIAs) during 
their effective periods (see below for more OBIA details).

Purpose and Background

    The Navy's primary mission is to maintain, train, equip, and 
operate combat-ready naval forces capable of accomplishing American 
strategic objectives, deterring maritime aggression, and assuring 
freedom of navigation in ocean areas. This mission is mandated by 
Federal law in Section 5062 of Title 10 of the United States Code, 
which directs the Secretary of the Navy and Chief of Naval Operations 
(CNO) to ensure the readiness of the U.S. naval forces.
    The Secretary of the Navy and the CNO have established that anti-
submarine warfare (ASW) is a critical capability for achieving the 
Navy's mission, and it requires unfettered access to both the high seas 
and littoral environments to be prepared for all potential threats by 
maintaining ASW core competency. The Navy is challenged by the 
increased difficulty in locating undersea threats solely by using 
passive acoustic technologies due to the advancement and use of 
quieting technologies in diesel-electric and nuclear submarines. At the 
same time as the distance at which submarine threats can be detected 
decreases due to quieting technologies, improvements in torpedo and 
missile design have extended the effective range of these weapons.
    One of the ways the Navy has addressed the changing requirements 
for ASW readiness was by developing SURTASS LFA sonar, which is able to 
reliably detect quieter and harder-to-find submarines at long range 
before these vessels can get within their effective weapons range to 
launch against their targets. SURTASS LFA sonar systems have a passive 
component (SURTASS), which is a towed line array of hydrophones used to 
detect sound emitted or reflected from submerged targets, and an active 
component (LFA), which is comprised of a set of acoustic transmitting 
elements. The active component detects objects by creating a sound 
pulse, or ``ping'' that is transmitted through the water and reflects 
off the target, returning in the form of an echo similar to 
echolocation used by some marine mammals to locate prey and navigate. 
SURTASS LFA sonar systems are long-range sensors that operate in the 
low-frequency (LF) band (i.e., 100-500 Hertz (Hz)). Because LF sound 
travels in seawater for greater distances than higher frequency sound, 
the SURTASS LFA sonar system would meet the need for improved detection 
and tracking of new-generation submarines at a longer range and would 
maximize the opportunity for U.S. armed forces to safely react to, and 
defend against, potential submarine threats while remaining a safe 
distance beyond a submarine's effective weapons range. Thus, the active 
acoustic component in the SURTASS LFA sonar is an important 
augmentation to its passive and tactical systems, as its long-range 
detection capabilities can effectively counter the threat to the Navy 
and national security interests posed by quiet, diesel submarines.

Dates and Duration

    Due to uncertainties in the world's political climate, a detailed 
account of future operating locations and conditions for SURTASS LFA 
sonar use over the next five years cannot be predicted. However, for 
analytical purposes, a nominal annual deployment schedule and 
operational concept were developed based on actual SURTASS LFA sonar 
activities conducted since January 2003 and projected Fleet 
requirements (See Table 1).

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         Table 1--Example Annual Deployment Schedule for One Surveillance Vessel Using SURTASS LFA Sonar
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                 On mission                        Days                   Off mission                  Days
----------------------------------------------------------------------------------------------------------------
Transit.....................................              54  In-Port Upkeep....................              40
Active Activities...........................             240  Regular Overhaul..................              31
(Up to 255 transmission hours based on a
 nominal 7.5% duty cycle).
Total Days on Mission.......................             294  Total Days off Mission............              71
----------------------------------------------------------------------------------------------------------------

    Annually, each vessel is expected to spend approximately 54 days in 
transit and 294 days at sea conducting military readiness activities, 
which includes 240 days of active operations (amounting to 255 
transmission hours based on a 7.5% duty cycle). Between missions, an 
estimated total of 71 days per year will be spent in port for upkeep 
and repair to maintain both the material condition of the vessel and 
its systems. The actual number and length of the individual missions 
within the 240 days are difficult to predict, but the maximum number of 
actual transmission hours per vessel per year will not exceed 255 
hours.
    As noted above, this would be the fourth continuous such 
authorization for the Navy's SURTASS LFA sonar activities. The Navy's 
current rule and LOA expire after August 14, 2017. Therefore, the Navy 
has requested MMPA rulemaking and will request annual LOAs for its 
SURTASS LFA sonar activities effective from August 15, 2017 through 
August 14, 2022, to take marine mammals incidental to the activities of 
up to four SURTASS LFA sonar systems. Subsequent LOA applications would 
be submitted annually throughout the remaining years of the new rule.

Potential SURTASS LFA Sonar Operational Areas

    Figure 1 depicts the potential areas of activities for SURTASS LFA 
sonar. In areas within 12 nmi from any shorelines (coastal exclusion 
areas) and in areas identified as OBIAs, SURTASS LFA sonar would be 
operated such that received levels of LFA sonar are below 180 dB re 1 
[mu]Pa rms sound pressure level (SPL). This restriction would be 
observed year-round for coastal exclusion areas and during periods of 
biological importance for OBIAs, but these areas are not depicted in 
Figure 1 as these areas are not visible at the map scale. Based on the 
Navy's current operational requirements, potential activities for 
SURTASS LFA sonar vessels from August 2017 through August 2022 would 
include areas located in the Pacific, Atlantic, and Indian Oceans as 
well as the Mediterranean Sea.
[GRAPHIC] [TIFF OMITTED] TP27AP17.000

    The Navy will not operate SURTASS LFA sonar pursuant to this rule 
in polar regions (i.e., Arctic and Antarctic waters) of the world (see 
shaded areas in Figure 1). The Arctic Ocean, the Bering Sea (including 
Bristol Bay and Norton Sound), portions of the Norwegian, Greenland, 
and Barents Seas north of 72[deg] North (N) latitude, plus Baffin Bay, 
Hudson Bay, and the Gulf of St. Lawrence would be non-operational areas 
for SURTASS LFA sonar. In the

[[Page 19463]]

Antarctic, the Navy will not conduct SURTASS LFA activities in areas 
south of 60[deg] South (S) latitude. The Navy has excluded polar waters 
from operational planning because of the inherent inclement weather 
conditions and the navigational and operational (equipment) danger that 
icebergs pose to SURTASS LFA sonar vessels.
    The Navy must anticipate, or predict, where they have to operate in 
the next five years for the MMPA rulemaking. Naval forces are presently 
operating in several areas strategic to U.S. national and international 
interests. National security needs may dictate that many of these 
operational areas will be close to ports and choke points, such as 
entrances to straits, channels, and canals. It is anticipated that many 
future naval conflicts are likely to occur within littoral or coastal 
areas. However, it is infeasible for the Navy to analyze all potential 
global mission areas for all species and stocks for all seasons. 
Instead, the Navy projects where it intends to use SURTASS LFA sonar 
for the next five-year authorization period based on today's political 
climate and provides NMFS with take estimates for marine mammal stocks 
in the proposed areas of activity. NMFS believes that this provides 
sufficient coverage for worldwide SURTASS LFA sonar activities, as 
specific take numbers are requested on an annual basis in applications 
for LOAs, subject to an annual cap of 12 percent per stock.
    For this fourth rulemaking, the Navy modeled and analyzed 26 
representative mission areas in the Pacific, Atlantic, and Indian 
Oceans and the Mediterranean Sea to represent the acoustic regimes and 
marine mammal species/stocks that may be encountered during worldwide 
SURTASS LFA sonar activities (see Table 2). They are comprised of the 
following modeled areas: East of Japan; north Philippine Sea; west 
Philippine Sea; offshore Guam; Sea of Japan; East China Sea; South 
China Sea; Offshore Japan (two locations: 25[deg] to 40[deg] N and 
10[deg] to 25[deg] N); Hawaii North; Hawaii South; Offshore Southern 
California; western north Atlantic; eastern North Atlantic; 
Mediterranean Sea; Arabian Sea; Andaman Sea; Panama Canal; northeast 
Australia; northwest Australia; northeast of Japan; southern Gulf of 
Alaska; southern Norwegian Basin (between Iceland and Norway); western 
North Atlantic (off of Virginia/Maryland); Labrador Sea; and Sea of 
Okhotsk. Since the Navy cannot forecast the location of its operations, 
annual requests will be submitted to NMFS that will include specific 
mission areas and modeling locations for each year's activities. For 
more details of the impact analysis, see Appendix B in the DSEIS/SOEIS.

  Table 2--Potential SURTASS LFA Sonar Activity Areas That the Navy Modeled for the DSEIS/OEIS (DoN, 2016a) and
                                       the MMPA Rulemaking/LOA Application
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                                     Location  (latitude/                                 Location  (latitude/
          Modeled site              longitude of center of          Modeled site         longitude of center of
                                        modeling area)                                       modeling area)
----------------------------------------------------------------------------------------------------------------
East of Japan...................  38[deg] N., 148[deg] E.     Eastern North Atlantic.  56.4[deg] N., 10[deg] W.
North Philippine Sea............  29[deg] N., 136[deg] E.     Mediterranean Sea......  39[deg] N., 6[deg] E.
West Philippine Sea.............  22[deg] N., 124[deg] E.     Arabian Sea............  14[deg]N., 65[deg] E.
Offshore Guam (Mariana Islands    11[deg] N., 145[deg] E.     Andaman Sea............  7.5[deg] N., 96[deg] E.
 Range Complex, outside Mariana
 Trench).
Sea of Japan....................  39[deg] N., 132[deg] E.     Panama Canal...........  5[deg] N., 81[deg] W.
East China Sea..................  26[deg] N., 125[deg] E.     Northeast Australia....  23[deg] S., 155[deg] E.
South China Sea.................  14[deg] N., 114[deg] E.     Northwest Australia....  18[deg] S., 110[deg] E.
Offshore Japan 25[deg] to         30[deg] N., 165[deg] E.     Northeast of Japan.....  52[deg] N., 163[deg] E.
 40[deg] N.
Offshore Japan 10[deg] to         15[deg] N., 165[deg] E.     Southern Gulf of Alaska  51[deg] N., 150[deg] W.
 25[deg] N.
Hawai'i North...................  25[deg] N., 158[deg] W.     Southern Norwegian       65[deg] N., 0[deg]
                                                               Basin (between Iceland
                                                               and Norway).
Hawaii South....................  19.5[deg] N., 158.5[deg]    Western North Atlantic   39.6[deg] N., 71.6[deg]
                                   W.                          (off of Virginia/        W.
                                                               Maryland).
Offshore Southern California....  32[deg] N., 120[deg] W.     Labrador Sea...........  57[deg] N., 50[deg] W.
Western North Atlantic (off       29[deg] N., 76[deg] W.      Sea of Okhotsk.........  51[deg] N., 150[deg] E.
 Florida).
----------------------------------------------------------------------------------------------------------------

    The use of the SURTASS LFA sonar system during at-sea activities 
would result in acoustic stimuli from the generation of sound or 
pressure waves in the water at or above levels that NMFS has determined 
would result in take of marine mammals under the MMPA. This is the 
principal means of marine mammal taking associated with these military 
readiness activities and the Navy has requested authorization to take 
marine mammals by Level B harassment. At no point are there expected to 
be more than four systems in use, and thus this proposed rule analyzes 
the impacts on marine mammals due to the deployment of up to four 
SURTASS LFA sonar systems for a five-year period between August 2017 
and August 2022.
    In addition to the use of active acoustic sources, the Navy's 
activities include the operation and movement of vessels. This document 
also analyzes the effects of this aspect of the activities. However, 
NMFS does not anticipate takes of marine mammals to result from ship 
strikes from any of the four SURTASS LFA vessels because each vessel 
moves at a relatively slow speed, especially when towing the SURTASS 
and LFA sonar systems, and for a relatively short period of time. 
Combined with the use of mitigation measures as noted below, it is 
likely that any marine mammal would be able to avoid the surveillance 
vessels.

Detailed Description of the Specified Activities

Description of SURTASS LFA Sonar
    SONAR is an acronym for Sound Navigation and Ranging, and its 
definition includes any system (biological or mechanical) that uses 
underwater sound, or acoustics, for detection, monitoring, and/or 
communications. Active sonar is the transmission of sound energy for 
the purpose of sensing the environment by interpreting features of 
received signals. Active sonar detects objects by creating a sound 
pulse, or ``ping'' that is transmitted through the water and reflects 
off the target, returning in the form of an echo. Passive sonar detects

[[Page 19464]]

the transmission of sound waves created by an object.
    As mentioned previously, the SURTASS LFA sonar system is a long-
range, all-weather LF sonar (operating between 100 and 500 Hertz (Hz)) 
system that has both active and passive components. LFA, the active 
system component (which allows for the detection of an object that is 
not generating noise), is comprised of source elements (called 
projectors) suspended vertically on a cable beneath the surveillance 
vessel. The projectors produce an active sound pulse by converting 
electrical energy to mechanical energy by setting up vibrations or 
pressure disturbances within the water to produce a ping. The Navy uses 
LFA as an augmentation to the passive SURTASS operations when passive 
system performance is inadequate. SURTASS, the passive part of the 
system, uses hydrophones (i.e., underwater microphones) to detect sound 
emitted or reflected from submerged targets, such as submarines. The 
SURTASS hydrophones are mounted on a horizontal line array that is 
towed behind the surveillance vessel. The Navy processes and evaluates 
the returning signals or echoes, which are usually below background or 
ambient sound level, to identify and classify potential underwater 
targets.
LFA Active Component
    The active component of the SURTASS LFA sonar system consists of up 
to 18 projectors suspended beneath the surveillance vessel in a 
vertical line array. The SURTASS LFA sonar projectors transmit in the 
low-frequency band (between 100 and 500 Hz). The source level of an 
individual projector in the SURTASS LFA sonar array is approximately 
215 dB re: 1 [mu]Pa at 1 m or less (Sound pressure is the sound force 
per unit area and is usually measured in micropascals ([mu]Pa), where 
one Pascal (Pa) is the pressure resulting from a force of one newton 
exerted over an area of one square meter. The commonly used reference 
pressure level in underwater acoustics is 1 [mu]Pa at 1 m, and the 
units for source level are decibels (dB) re: 1 [mu]Pa at 1 m). Because 
of the physics involved in acoustic beamforming (i.e., a method of 
mapping noise sources by differentiating sound levels based upon the 
direction from which they originate) and sound transmission loss 
processes, the SURTASS LFA sonar array cannot have a SPL higher than 
the SPL of an individual projector.
    The SURTASS LFA sonar acoustic transmission is an omnidirectional 
beam (a full 360 degrees ([deg])) in the horizontal plane. The LFA 
sonar system also has a narrow vertical beam that the vessel's crew can 
steer above or below the horizontal plane. The typical SURTASS LFA 
sonar signal is not a constant tone, but rather a transmission of 
various signal types that vary in frequency and duration (including 
continuous wave (CW) and frequency-modulated (FM) signals). A complete 
sequence of sound transmissions, also referred to by the Navy as a 
``ping'' or a wavetrain, can be as short as six seconds (sec) or last 
as long as 100 sec, with an average length of 60 sec. Within each ping, 
the duration of any continuous frequency sound transmission is no 
longer than 10 sec and the time between pings is typically from six to 
15 minutes (min). Based on the Navy's historical operating parameters, 
the average duty cycle (i.e., the ratio of sound ``on'' time to total 
time) for LFA sonar is normally 7.5 to 10 percent and the duty cycle is 
not expected to exceed 20 percent.
Compact LFA Active Component
    In addition to the LFA sonar system deployed on the USNS 
IMPECCABLE, the Navy developed a compact LFA (CLFA) sonar system now 
deployed on its three smaller surveillance vessels (i.e., the USNS 
ABLE, EFFECTIVE, and VICTORIOUS). In the application, the Navy 
indicates that the operational characteristics of the active component 
CLFA sonar are comparable to the existing LFA systems and that the 
potential impacts from CLFA will be similar to the effects from the 
existing LFA sonar system. The CLFA sonar system consists of smaller 
projectors that weigh 142,000 lbs (64,410 kilograms (kg)), which is 
182,000 lbs (82,554 kg) less that the mission weight of the LFA 
projectors on the USNS IMPECCABLE. The CLFA sonar system also consists 
of up to 18 projectors suspended beneath the surveillance vessel in a 
vertical line array and the CLFA sonar projectors transmit in the low-
frequency band (also between 100 and 500 Hz) with the same duty cycle 
as described for LFA sonar. Similar to the active component of the LFA 
sonar system, the source level of an individual projector in the CLFA 
sonar array is approximately 215 dB re: 1 [mu]Pa or less.
    For the analysis in this rulemaking, NMFS will use the term LFA to 
refer to both the LFA sonar system and/or the CLFA sonar system, unless 
otherwise specified.
SURTASS Passive Component
    The passive component of the SURTASS LFA sonar system consists of a 
SURTASS Twin-line (TL-29A) horizontal line array mounted with 
hydrophones. The Y-shaped array is 1,000 ft (305 m) in length and has 
an operational depth of 500 to 1,500 ft (152.4 to 457.2 m). The SURTASS 
LFA sonar vessel typically maintains a speed of at least 3.4 mph (5.6 
km/hr; 3 knots (kts)) to tow the array astern of the vessel in the 
correct horizontal configuration.
High-Frequency Active Sonar
    Although technically not part of the SURTASS LFA sonar system, the 
Navy also proposes to use a high-frequency sonar system, called the 
High Frequency Marine Mammal Monitoring sonar (HF/M3 sonar), to detect 
and locate marine mammals within the SURTASS LFA sonar activity areas 
and mitigation and buffer zones, as described later in this proposed 
rule. This enhanced commercial fish-finding sonar, mounted at the top 
of the SURTASS LFA sonar vertical line array, has a source level of 220 
dB re: 1 [mu]Pa at 1 m with a frequency range from 30 to 40 kilohertz 
(kHz). The duty cycle is variable, but is normally below three to four 
percent and the maximum pulse duration is 40 milliseconds. The HF/M3 
sonar has four transducers with 8[deg] horizontal and 10[deg] vertical 
beamwidths, which sweep a full 360[deg] in the horizontal plane every 
45 to 60 sec with a maximum range of approximately 1.2 mi (2 km).
Vessel Specifications
    The Navy proposes to deploy the SURTASS LFA sonar system on a 
maximum of four U.S. Naval ships: the USNS ABLE (T-AGOS 20), the USNS 
EFFECTIVE (T-AGOS 21), the USNS IMPECCABLE (T-AGOS 23) and the USNS 
VICTORIOUS (T-AGOS 19).
    The USNS ABLE, EFFECTIVE, and VICTORIOUS, are twin-hulled ocean 
surveillance ships. Each vessel has a length of 235 feet (ft) (71.6 
meters (m)); a beam of 93.6 ft (28.5 m); a maximum draft of 25 ft (7.6 
m); and a full load displacement of 3,396 tons (3,451 metric tons). A 
twin-shaft diesel electric engine provides 3,200 horsepower (hp), which 
drives two propellers.
    The USNS IMPECCABLE, also a twin-hulled ocean surveillance ship, 
has a length of 281.5 ft (85.8 m); a beam of 95.8 ft (29.2 m); a 
maximum draft of 26 ft (7.9 m); and a full load displacement of 5,368 
tons (5,454 metric tons). A twin-shaft diesel electric engine provides 
5,000 hp, which drives two propellers.
    The operational speed of each vessel during sonar activities will 
be approximately 3.4 miles per hour (mph) (5.6 km per hour (km/hr); 3 
knots (kt)) and each vessel's cruising speed outside

[[Page 19465]]

of sonar activities would be a maximum of approximately 11.5 to 14.9 
mph (18.5 to 24.1 km/hr; 10 to 13 kts). During sonar activities, the 
SURTASS LFA sonar vessels will generally travel in straight lines or in 
oval-shaped (i.e., racetrack) patterns depending on the operational 
scenario.
    Each vessel also has an observation area on the bridge from where 
lookouts will monitor for marine mammals before and during LFA sonar 
activities. When stationed on the bridge of the USNS ABLE, EFFECTIVE, 
or VICTORIOUS, the lookout's eye level will be approximately 32 ft (9.7 
m) above sea level providing an unobstructed view around the entire 
vessel. For the USNS IMPECCABLE, the lookout's eye level will be 
approximately 45 ft (13.7 m) above sea level.

Notice of Receipt Comments and Responses

    On October 21, 2016, NMFS published a notice of receipt (NOR) of an 
application for rulemaking in the Federal Register (81 FR 72782) and 
requested comments and information from the interested public for 30 
days. During the 30-day comment period, which ended on November 21, 
2016, NMFS received one comment from an environmental non-governmental 
organization. This comment stated that the Navy should address several 
shortcomings in the application such as: (1) Update the information of 
the impacts of LFA sonar on sensitive federal protected species and 
their critical habitat; (2) increase the number of offshore biological 
important areas and expand others to include marine mammal critical 
habitat; (3) increase current buffer zones to reduce impacts of LFA 
sonar; (4) update the scientific information of the impact of LFA sonar 
on marine mammals; (5) provide an analysis of negative effects for 
information-poor populations; (6) analyze cumulative impacts of LFA 
sonar, including the synergistic/additive effects of climate change; 
and (7) include additional mitigation measures to reduce LFA sonar 
impacts.
    The Navy addressed impacts to endangered and threatened species and 
critical habitat in their application, and the Navy and NMFS' Office of 
Protected Resources Permits and Conservation Division are currently in 
consultation with NMFS' Office of Protected Resources ESA Interagency 
Consultation Division. Consistent with the 1989 preamble for NMFS' 
implementing regulations (54 FR 40338, September 29, 1989), the impacts 
from past and ongoing anthropogenic activities are reflected in the 
environmental baseline (e.g., these impacts are reflected in the 
density/distribution and status of the species, population size and 
growth rate, and ambient noise). The reader is also referred to the 
2016 DSEIS/SOEIS for more detailed information, including the 
cumulative impacts and climate change analyses. As noted in the Navy's 
application, as well as the DSEIS/SOEIS (for which NMFS is a 
cooperating agency with the Navy for purposes of adopting the DSEIS for 
this action and in this proposed rule, the number of biologically 
important areas under consideration have been expanded (commenter noted 
there are only 22 OBIAs, but there are 28 included in the application 
and DSEIS/SOEIS). NMFS has addressed the issue of increased buffer 
zones in previous rulemaking, and it was determined that this was not 
warranted (see 77 FR 50290, August 20, 2012, Comment 36 Response, and 
response to comment NRDC-17 of the Navy's 2012 FSEIS/SOEIS for 
rationale for the additional 1 km buffer). Reanalysis of the matter in 
this rule confirms this determination. Required buffer zones imposed by 
NMFS on the Navy's SURTASS LFA sonar include an additional 1 km buffer 
zone around the Navy's LFA Mitigation Zone and an additional 1 km 
buffer zone seaward of any OBIA during the time of biological 
importance. Implementation of the additional 1 km buffer zone will 
ensure that no marine mammals are exposed to an SPL greater than 
approximately 174 dB re: 1 [mu]Pa, which is below levels for which most 
marine mammals are anticipated to experience onset of TTS or PTS, and 
therefore limits potential takes to lower-level Level B behavioral 
harassment. Lastly, NMFS and Navy evaluated ways to address data-poor 
scenarios and potential additional mitigation measures as part of the 
rulemaking process and ongoing adaptive management, which is described 
in more detail below.
    The Marine Mammal Commission (MMC) did not submit comments in 
response to the NOR, but had previously submitted comments to the Navy 
and NMFS in response to the Navy's DSEIS/OEIS, and stated that these 
comments would also suffice as their comments on the Navy's 
application. The MMC made recommendations to use the best available 
science plus some measure of uncertainty (e.g., mean plus two standard 
deviations, mean plus the coefficient of variation, the upper limit of 
the confidence level) in instances where density data were extrapolated 
due to data not being available; that the Navy make its Marine Species 
Density Database (NMSDD) available to the public as soon as possible, 
specify how density estimates were derived, and what statistic (e.g., 
mean, median, maximum) was used when multiple sources are referenced; 
expressed concern regarding the Navy's use of the single ping 
equivalent (SPE) metric (discussed in more detail below), and 
recommended that the Navy either use the SPL or sound exposure level 
(SEL) metric in assessment of behavioral risk from exposure to SURTASS 
LFA sonar, or use behavior response metrics and thresholds based on 
Finneran and Jenkins (2012); recommended that the Navy amend its DSEIS/
SOEIS to specify the numbers of marine mammals that could be taken by 
Level A and B harassment incidental to operating SURTASS LFA sonar, 
rather than providing the percentages of each stock for such takes; 
requested further clarification in regard to whether there were zero 
Level A takes modeled, or if Level A takes were reduced to zero with 
mitigation applied; and expressed agreement with the proposed expansion 
of five OBIAs and the addition of six new OBIAs, but requested 
additional information on the evaluation for determining that other 
areas did not meet the criteria for designation as OBIAs.
    Regarding the NMSDD, all data sources that go into the database are 
cited so they can be obtained. Some of the data sources are 
proprietary, so the Navy is unable to provide the NMSDD in GIS 
shapefile format because they only have a license for the Navy. NMFS 
notes that the single ping equivalent (SPE) has been used in each of 
the previous rulemakings and NMFS continues to believe the use of this 
metric is appropriate for assessing behavioral responses for SURTASS 
LFA sonar because it is a conservative estimate that accounts for the 
increased potential for behavioral responses due to repeated exposures 
by adding 5 x log10 (number of pings) to each 1-dB received level (RL) 
increment, and sums these across all dB levels to determine the dB SPE 
for each modeled animal (i.e., SPE is a cumulative metric which 
accounts for not only the level of exposure but also the duration of 
exposure). The behavior response data used to derive Finneran and 
Jenkins (2012) thresholds were from mid-frequency sources, while the 
data used to derive the behavioral thresholds for SURTASS LFA were 
specifically from studies using the actual source. Therefore, NMFS 
feels they are more appropriate to apply to SURTASS LFA sonar. Also, as 
in previous rulemakings, the proposed rule does not specify the

[[Page 19466]]

number of marine mammals that may be taken in the proposed locations 
because these numbers are determined annually through various inputs 
such as mission location, mission duration, and season of operation. As 
with previous rulemakings, this proposed rule analyzes a maximum of 12 
percent takes by Level B harassment per stock annually, and the Navy 
will use the 12 percent limit to guide its mission planning and annual 
LOA applications as described in more detail below. We also note that 
the analysis for this rulemaking used the updated thresholds per the 
NMFS 2016 Acoustic Technical Guidance, and based on this analysis, NMFS 
and the Navy believe that it is unlikely that Level A Harassment takes 
are likely to occur, and therefore none are proposed to be authorized. 
Lastly, in regard to OBIAs, we continue to work with the Navy in 
reviewing and analyzing OBIAs as part of adaptive management. As 
described in the 2012 rulemaking as well as the Navy's 2016 application 
and DSEIS/SOEIS, as new information becomes available, areas are re-
evaluated to determine if any areas should be added or expanded. NMFS 
has also evaluated the recommendations in a white paper written by NMFS 
scientists (discussed in detail below).

Description of Marine Mammals in the Area of the Specified Activities

    One hundred and four (104) currently classified marine mammal 
species or stocks have confirmed or possible occurrence within 
potential SURTASS LFA activity areas in certain areas of the Pacific, 
Atlantic, and Indian Oceans and the Mediterranean Sea. Fifteen (15) 
species of baleen whales (mysticetes), 60 species of toothed whales, 
dolphins, or porpoises (odontocetes), and 29 species of seals or sea 
lions (pinnipeds) could be affected by SURTASS LFA sonar activities. 
Multiple stocks of some species are affected, and independent 
assessments are conducted to make the necessary findings and 
determinations for each of these.
    There are 20 marine mammal species under NMFS' jurisdiction that 
are listed as endangered or threatened under the Endangered Species Act 
(ESA; 16 U.S.C. 1531 et seq.) with confirmed or possible occurrence in 
potential activity areas for SURTASS LFA sonar. Marine mammal species 
under NMFS' jurisdiction listed as endangered include: The blue whale 
(Balaenoptera musculus); fin whale (Balaenoptera physalus); sei whale 
(Balaenoptera borealis); the Arabian Sea, Cape Verde Islands/Northwest 
Africa, Central America, and Western North Pacific distinct population 
segments (DPS) of humpback whale (Megaptera novaeangliae); bowhead 
whale (Balaena mysticetus); North Atlantic right whale (Eubalaena 
glacialis); North Pacific right whale (Eubalaena japonica); southern 
right whale (Eubalaena australis); Western North Pacific population of 
gray whale (Eschrichtius robustus); sperm whale (Physeter 
macrocephalus); the Cook Inlet stock of beluga whale (Delphinapterus 
leucas); the main Hawaiian Islands Insular DPS of false killer whale 
(Psuedorca crassidens); the Southern Resident population of Killer 
whale (Orca orcinus); the Western DPS of the Steller sea lion 
(Eumetopias jubatus); Mediterranean monk seal (Monachus monachus); and 
Hawaiian monk seal (Monachus schauinslandi). Marine mammal species 
under NMFS' jurisdiction listed as threatened include: The Guadalupe 
fur seal (Arctocephalus townsendi); the Okhotsk ringed seal (Pusa 
hispida ochotensis); the Okhotsk DPS of Pacific bearded seal 
(Erignathus barbatus nauticus); the southern DPS of the spotted seal 
(Phoca largha); and the Mexico DPS of humpback whale (Megaptera 
novaeangliae). Additionally, the Gulf of Mexico subspecies of the 
Bryde's whale has recently been proposed for listing under the ESA as 
endangered. The aforementioned threatened and endangered marine mammal 
species also are depleted under the MMPA.
    Three of the 104 species or stocks with potential occurrences 
within possible SURTASS LFA activity areas are considered depleted 
under the MMPA but are not ESA-listed. They are: The Eastern 
(Loughlin's) Steller sea lion (Eumetopias jubatus monteriensis); the 
Pribilof Island/Eastern Pacific stock of northern fur seal (Callorhinus 
ursinus); and the arctic ringed seal (Pusa hispida hispida).
    Chinese river dolphins (Lipotes vexillifer) and vaquita (Phocoena 
sinus) do not have stocks designated within potential SURTASS LFA sonar 
operational areas (see Potential SURTASS LFA Operational Areas 
section). The distribution of the Chinese river dolphin is limited to 
the main channel of a river section between the cities of Jingzhou and 
Jiangyin. The vaquita's distribution is restricted to the upper portion 
of the northern Gulf of California, mostly within the Colorado River 
delta. Based on the extremely rare occurrence of these species in the 
Navy's operational areas and coastal standoff range (i.e., distance of 
22 km (13 mi; 12 nmi) from land), take of Chinese river dolphins or 
vaquita is not considered a reasonable likelihood; therefore these 
species are not addressed further in this document.
    The U.S. Fish and Wildlife Service (USFWS) is responsible for 
managing the following marine mammal species: Southern sea otter 
(Enhydra lutris), polar bear (Ursus maritimus), walrus (Odobenus 
rosmarus), west African manatee (Trichechus senegalensis), Amazonian 
manatee (Trichechus inunguis), west Indian manatee (Trichechus 
manatus), and dugong (Dugong dugon). None of these species occur in 
geographic areas that would overlap with SURTASS LFA sonar operational 
areas. Therefore, the Navy has determined that SURTASS LFA sonar 
activities would have no effect on the endangered or threatened species 
or the critical habitat of the ESA-listed species under the 
jurisdiction of the USFWS. These species are not considered further in 
this notice.
    Tables 3 through 28 (below) summarize the abundance, status under 
the ESA, and density estimates of the marine mammal species and stocks 
that have confirmed or possible occurrence within 26 SURTASS LFA sonar 
operating areas in the Pacific, Indian, and Atlantic Oceans and 
Mediterranean Sea. To accurately assess the potential effects of 
worldwide SURTASS LFA sonar activities, the Navy modeled 26 
representative sites based on the Navy's current assessment of current 
and future requirements or threats.

  Table 3--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                      With Mission Area 1, the Sea of Japan
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                 Stock      Density (animals/
              Species                    Stock name \1\      abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  WNP..................           9,250            \5\ NA  EN
Fin whale..........................  WNP..................           9,250            0.0002  EN
Sei whale..........................  NP...................           7,000            0.0006  EN

[[Page 19467]]

 
Bryde's whale......................  WNP..................          20,501            0.0006  NL
Minke whale........................  WNP ``O'' Stock......          25,049            0.0022  NL
North Pacific right whale..........  WNP..................             922                NA  EN
Humpback whale.....................  WNP..................           1,328           0.00036  EN
Sperm whale........................  NP...................         102,112           0.00123  EN
Harbor porpoise....................  WNP..................          31,046            0.0190  NL
Baird's beaked whale...............  WNP..................           8,000            0.0029  NL
Cuvier's beaked whale..............  WNP..................          90,725            0.0031  NL
Ginkgo-toothed beaked whale........  NP...................          22,799            0.0005  NL
Hubbs beaked whale.................  NP...................          22,799            0.0005  NL
False killer whale.................  WNP--Pelagic.........          16,668            0.0036  NL
Pygmy killer whale.................  WNP..................          30,214            0.0021  NL
Short-finned pilot whale...........  WNP..................          53,608            0.0128  NL
Risso's dolphin....................  WNP..................          83,289            0.0097  NL
Short-beaked common dolphin........  WNP..................       3,286,163            0.0761  NL
Killer whale.......................  WNP..................          12,256            0.0001  NL
Common bottlenose dolphin..........  WNP..................         168,791            0.0171  NL
Pantropical spotted dolphin........  WNP..................         438,064            0.0259  NL
Striped dolphin....................  WNP..................         570,038            0.0111  NL
Spinner dolphin....................  WNP..................       1,015,059           0.00083  NL
Pacific white-sided dolphin........  NP...................         931,000            0.0082  NL
Rough-toothed dolphin..............  WNP..................         145,729            0.0059  NL
Kogia spp..........................  WNP..................         350,553            0.0031  NL
Stejneger's beaked whale...........  WNP..................           8,000            0.0005  NL
----------------------------------------------------------------------------------------------------------------
\1\ NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.


  Table 4--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                           With Mission Area 2, North Philippine Sea Operational Area
                                                  [Fall season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     Km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Bryde's whale......................  WNP..................          20,501            0.0006  NL
Minke whale........................  WNP ``O'' Stock......          25,049            0.0044  NL
North Pacific right whale..........  WNP..................             922            \5\ NA  EN
Blue whale.........................  WNP..................           9,250            .00001  EN
Fin whale..........................  WNP..................           9,250                NA  EN
Humpback whale.....................  WNP..................           1,328            .00089  EN
Omura's whale......................  WNP..................           1,800            .00006  NL
Sperm whale........................  NP...................         102,112           0.00123  EN
Common bottlenose dolphin..........  WNP..................         168,791            0.0146  NL
Cuvier's beaked whale..............  WNP..................          90,725            0.0054  NL
Blainville's beaked whale..........  WNP..................           8,032            0.0005  NL
Ginkgo-toothed beaked whale........  NP...................          22,799            0.0005  NL
Killer whale.......................  WNP..................          12,256           0.00009  NL
False killer whale.................  WNP--Pelagic.........          16,668            0.0029  NL
Pygmy killer whale.................  WNP..................          30,214            0.0021  NL
Melon-headed whale.................  WNP..................          36,770           0.00428  NL
Short-finned pilot whale...........  WNP..................          53,608            0.0153  NL
Risso's dolphin....................  WNP..................          83,289            0.0106  NL
Short-beaked common dolphin........  WNP..................       3,286,163            0.0562  NL
Fraser's dolphin...................  WNP..................         220,789            0.0069  NL
Kogia spp..........................  WNP..................         350,553            0.0031  *
Long-beaked common dolphin.........  WNP..................         279,182            0.1158  NL
Longman's beaked whale.............  WNP..................           4,571           0.00025  NL
Pantropical spotted dolphin........  WNP..................         438,064            0.0137  NL
Striped dolphin....................  WNP..................         570,038            0.0329  NL
Spinner dolphin....................  WNP..................       1,015,059           0.00083  NL
Pacific white-sided dolphin........  NP...................         931,000                NA  NL
Rough-toothed dolphin..............  WNP..................         145,729            0.0059  NL
----------------------------------------------------------------------------------------------------------------
\1\ NP = north Pacific; WNP = western north Pacific.

[[Page 19468]]

 
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.


  Table 5--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                            With Mission Area 3, West Philippine Sea Operational Area
                                                  [Fall season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  WNP..................           9,250            .00001  EN
Bryde's whale......................  WNP..................          20,501            0.0006  NL
Minke whale........................  WNP ``O'' Stock......          25,049            0.0033  NL
Fin whale..........................  WNP..................           9,250            \5\ NA  EN
Humpback whale.....................  WNP..................           1,328           0.00089  EN
Omura's whale......................  WNP..................           1,800           0.00006  NL
Sperm whale........................  NP...................         102,112           0.00123  EN
Killer whale.......................  WNP..................          12,256           0.00009  NL
Cuvier's beaked whale..............  WNP..................          90,725            0.0003  NL
Blainville`s beaked whale..........  WNP..................           8,032            0.0005  NL
Ginkgo-toothed beaked whale........  NP...................          22,799            0.0005  NL
False killer whale.................  WNP--Pelagic.........          16,668            0.0029  NL
Pygmy killer whale.................  WNP..................          30,214            0.0021  NL
Melon-headed whale.................  WNP..................          36,770           0.00428  NL
Short-finned pilot whale...........  WNP..................          53,608            0.0076  NL
Risso's dolphin....................  WNP..................          83,289            0.0106  NL
Kogia spp..........................  WNP..................         350,553            0.0017  *
Fraser's dolphin...................  WNP..................         220,789            0.0069  NL
Common bottlenose dolphin..........  WNP..................         168,791            0.0146  NL
Deraniyagala's beaked whale........  NP...................          22,799            0.0005  NL
Pantropical spotted dolphin........  WNP..................         438,064            0.0137  NL
Striped dolphin....................  WNP..................         570,038            0.0164  NL
Spinner dolphin....................  WNP..................       1,015,059           0.00083  NL
Rough-toothed dolphin..............  WNP..................         145,729            0.0059  NL
Long-beaked common dolphin.........  WNP..................         279,182            0.1158  NL
Longman's beaked whale.............  WNP..................           4,571           0.00025  NL
----------------------------------------------------------------------------------------------------------------
\1\ NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.


  Table 6--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                       With Mission Area 4, Offshore Guam
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  WNP..................           9,250            NA \5\  EN
Fin whale..........................  WNP..................           9,250                NA  EN
Sei whale..........................  NP...................           7,000                NA  EN
Bryde's whale......................  WNP..................          20,501            0.0004  NL
Minke whale........................  WNP ``O'' Stock......          25,049                NA  NL
Humpback whale.....................  WNP..................           1,328                NA  EN
Omura's whale......................  WNP..................           1,800           0.00004  NL
Sperm whale........................  NP...................         102,112           0.00123  EN
Pygmy sperm whale..................  WNP..................         350,553           0.00291  NL
Dwarf sperm whale..................  WNP..................         350,553           0.00714  NL
Cuvier's beaked whale..............  WNP..................          90,725           0.00079  NL
Blainville's beaked whale..........  WNP..................           8,032             0.001  NL
Ginkgo-toothed beaked whale........  NP...................          22,799           0.00093  NL
Longman's beaked whale.............  WNP..................           4,571            0.0019  NL
Killer whale.......................  WNP..................          12,256           0.00014  NL
False killer whale.................  WNP--Pelagic.........          16,668           0.00111  NL
Pygmy killer whale.................  WNP..................          30,214           0.00014  NL
Melon-headed whale.................  NMI..................           2,455           0.00428  NL
Short-finned pilot whale...........  WNP..................          53,608            0.0051  NL
Risso's dolphin....................  WNP..................          83,289             0.003  NL
Deraniyagala's beaked whale........  NP...................          22,799           0.00093  NL
Fraser's dolphin...................  CNP..................          16,992            0.0069  NL

[[Page 19469]]

 
Common bottlenose dolphin..........  WNP..................         168,791           0.00245  NL
Pantropical spotted dolphin........  WNP..................         438,064            0.0226  NL
Striped dolphin....................  WNP..................         570,038           0.00616  NL
Spinner dolphin....................  WNP..................       1,015,059           0.00083  NL
Rough-toothed dolphin..............  WNP..................         145,729            0.0026  NL
----------------------------------------------------------------------------------------------------------------
\1\ CNP = central north Pacific; NP = north Pacific; WNP = western north Pacific; NMI = Northern Mariana
  Islands.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.


  Table 7--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                        With Mission Area 5, Sea of Japan
                                                  [Fall season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Fin whale..........................  WNP..................           9,250            0.0009  EN
Bryde's whale......................  WNP..................          20,501            0.0001  NL
Minke whale........................  WNP ``O'' Stock......          25,049            0.0004  NL
Minke whale........................  WNP ``J'' Stock......             893           0.00016  NL
North Pacific right whale..........  WNP..................             922            \5\ NA  EN
Gray whale.........................  WNP..................             140           0.00001  EN \6\
Omura's whale......................  WNP..................           1,800           0.00001  NL
Sperm whale........................  NP...................         102,112           0.00123  EN
Stejneger's beaked whale...........  WNP..................           8,000            0.0005  NL
Baird's beaked whale...............  WNP..................           8,000            0.0003  NL
Cuvier's beaked whale..............  WNP..................          90,725            0.0031  NL
Harbor porpoise....................  WNP..................          31,046            0.0190  NL
False killer whale.................  IA-Pelagic...........           9,777            0.0027  NL
Killer whale.......................  WNP..................          12,256           0.00009  NL
Short-finned pilot whale...........  WNP..................          53,608            0.0014  NL
Risso's dolphin....................  IA...................          83,289            0.0073  NL
Short-beaked common dolphin........  WNP..................       3,286,163            0.0860  NL
Common bottlenose dolphin..........  IA...................         105,138           0.00077  NL
Kogia spp..........................  WNP..................         350,553            0.0017  *
Spinner dolphin....................  WNP..................       1,015,059           0.00083  NL
Pacific white-sided dolphin........  NP...................         931,000                NA  NL
Dall's porpoise....................  SOJ..................         173,638            0.0520  NL
Long-beaked common dolphin.........  WNP..................         279,182            0.1158  NL
Rough-toothed dolphin..............  WNP..................         145,729            0.0026  NL
Striped dolphin....................  IA...................         570,038           0.00584  NL
Spotted seal.......................  Southern stock.......           3,500           0.00001  T
----------------------------------------------------------------------------------------------------------------
\1\ IA = Inshore Archipelago; NP = north Pacific; SOJ = Sea of Japan; WNP = western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.
\6\ Only the western Pacific population of gray whale is endangered under the ESA.


  Table 8--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                       With Mission Area 6, East China Sea
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock Name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Fin whale..........................  ECS..................             500            0.0002  EN
Bryde's whale......................  ECS..................             137            0.0003  NL
Minke whale........................  WNP ``O'' Stock......          25,049            0.0044  NL
Minke whale........................  WNP ``J'' Stock......             893            0.0018  NL
North Pacific right whale..........  WNP..................             922            \5\ NA  EN
Gray whale.........................  WNP..................             140                NA  EN \6\
Omura's whale......................  WNP..................           1,800           0.00003  NL

[[Page 19470]]

 
Sperm whale........................  NP...................         102,112           0.00123  EN
Cuvier's beaked whale..............  WNP..................          90,725            0.0003  NL
Blainville's beaked whale..........  WNP..................           8,032            0.0005  NL
Ginkgo-toothed beaked whale........  NP...................          22,799            0.0005  NL
False killer whale.................  IA-Pelagic...........           9,777           0.00111  NL
Pygmy killer whale.................  WNP..................          30,214           0.00014  NL
Melon-headed whale.................  WNP..................          36,770           0.00428  NL
Short-finned pilot whale...........  WNP..................          53,608            0.0016  NL
Risso's dolphin....................  IA...................          83,289            0.0106  NL
Short-beaked common dolphin........  WNP..................       3,286,163            0.0461  NL
Fraser's dolphin...................  WNP..................         220,789           0.00694  NL
Common bottlenose dolphin..........  IA...................         105,138           0.00077  NL
Pantropical spotted dolphin........  WNP..................         219,032           0.01374  NL
Striped dolphin....................  IA...................         570,038           0.00584  NL
Spinner dolphin....................  WNP..................       1,015,059           0.00083  NL
Pacific white-sided dolphin........  NP...................         931,000                NA  NL
Rough-toothed dolphin..............  WNP..................         145,729            0.0026  NL
Killer whale.......................  WNP..................          12,256           0.00009  NL
Kogia spp..........................  WNP..................         350,553            0.0017  *
Long-beaked common dolphin.........  WNP..................         279,182            0.1158  NL
Longman's beaked whale.............  WNP..................           4,571           0.00025  NL
Spotted seal.......................  Southern stock.......           1,000           0.00001  T
----------------------------------------------------------------------------------------------------------------
\1\ ECS = East China Sea; IA = Inshore Archipelago; NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.
\6\ Only the western Pacific population of gray whale is endangered under the ESA.


  Table 9--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                      With Mission Area 7, South China Sea
                                                  [Fall season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Fin whale..........................  WNP..................           9,250            0.0002  EN
Bryde's whale......................  WNP..................          20,501            0.0006  NL
Minke whale........................  WNP ``O'' Stock......          25,049            0.0033  NL
Minke whale........................  WNP ``J'' Stock......             893            0.0018  NL
Humpback whale.....................  WNP..................           1,328           0.00036  EN
North Pacific right whale..........  WNP..................             922            \5\ NA  EN
Omura's whale......................  WNP..................           1,800          0. 00006  NL
Gray whale.........................  WNP..................             140           0.00001  EN \6\
Sperm whale........................  NP...................         102,112            0.0012  EN
Long-beaked common dolphin.........  WNP..................         279,182            0.1158  NL
Cuvier's beaked whale..............  WNP..................          90,725            0.0003  NL
Blainville's beaked whale..........  WNP..................           8,032            0.0005  NL
Ginkgo-toothed beaked whale........  NP...................          22,799            0.0005  NL
False killer whale.................  IA-Pelagic...........           9,777           0.00111  NL
Pygmy killer whale.................  WNP..................          30,214           0.00014  NL
Melon-headed whale.................  WNP..................          36,770           0.00428  NL
Short-finned pilot whale...........  WNP..................          53,608           0.00159  NL
Risso's dolphin....................  IA...................          83,289            0.0106  NL
Longman's beaked whale.............  WNP..................           4,571           0.00025  NL
Fraser's dolphin...................  WNP..................         220,789           0.00694  NL
Common bottlenose dolphin..........  IA...................         105,138           0.00077  NL
Pantropical spotted dolphin........  WNP..................         219,032           0.01374  NL
Striped dolphin....................  IA...................         570,038           0.00584  NL
Spinner dolphin....................  WNP..................       1,015,059           0.00083  NL
Rough-toothed dolphin..............  WNP..................         145,729            0.0026  NL
Deraniyagala's beaked whale........  NP...................          22,799            0.0005  NL
Killer whale.......................  WNP..................          12,256           0.00009  NL
Kogia spp..........................  WNP..................         350,553            0.0017  *
----------------------------------------------------------------------------------------------------------------
\1\ IA = Inshore Archipelago; NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.

[[Page 19471]]

 
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.
\6\ Only the western Pacific population of gray whale is endangered under the ESA.


 Table 10--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                            With Mission Area 8, Offshore Japan 25[deg] to 40[deg] N.
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                                 Density
              Species                    Stock name \1\      Abundance \2\   (animals/km\2\)    ESA  status \4\
                                                                                   \3\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  WNP..................           9,250             \5\NA  EN
Fin whale..........................  WNP..................           9,250            0.0001  EN
Sei whale..........................  NP...................           7,000           0.00029  EN
Bryde's whale......................  WNP..................          20,501           0.00041  NL
Minke whale........................  WNP ``O'' Stock......          25,049            0.0003  NL
Humpback whale.....................  WNP..................           1,328           0.00036  EN
Sperm whale........................  NP...................         102,112            0.0022  EN
Pygmy sperm whale..................  WNP..................         350,553            0.0018  NL
Dwarf sperm whale..................  WNP..................         350,553            0.0043  NL
Northern right whale dolphin.......  NP...................          68,000                NA  NL
Blainville's beaked whale..........  WNP..................           8,032            0.0007  NL
Hubb's beaked whale................  NP...................          22,799            0.0005  NL
Killer whale.......................  WNP..................          12,296           0.00009  NL
Longman's beaked whale.............  WNP..................           4,571            0.0003  NL
Baird's beaked whale...............  WNP..................           8,000            0.0001  NL
Cuvier's beaked whale..............  NP...................          90,725           0.00374  NL
Mesoplodon spp.....................  WNP..................          22,799            0.0005  NL
False killer whale.................  WNP-Pelagic..........          16,668            0.0036  NL
Pygmy killer whale.................  WNP..................          30,214            0.0001  NL
Melon-headed whale.................  WNP..................          36,770            0.0027  NL
Short-finned pilot whale...........  WNP..................          53,608            0.0021  NL
Risso's dolphin....................  WNP..................          83,289            0.0005  NL
Short-beaked common dolphin........  WNP..................       3,286,163            0.0863  NL
Common bottlenose dolphin..........  WNP..................         168,791           0.00077  NL
Pantropical spotted dolphin........  WNP..................         438,064            0.0113  NL
Striped dolphin....................  WNP..................         570,038            0.0058  NL
Spinner dolphin....................  WNP..................       1,015,059            0.0019  NL
Pacific white-sided dolphin........  NP...................         931,000            0.0048  NL
Rough-toothed dolphin..............  WNP..................         145,729            0.0019  NL
Stejneger's beaked whale...........  WNP..................           8,000            0.0005  NL
Hawaiian monk seal.................  Hawaii...............           1,400           0.00001  EN
Northern fur seal..................  Western Pacific......         503,609                NA  NL
----------------------------------------------------------------------------------------------------------------
\1\ NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.


 Table 11--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                            With Mission Area 9, Offshore Japan 10[deg] to 25[deg] N.
                                                 [Winter season]
----------------------------------------------------------------------------------------------------------------
                                                                                 Density
              Species                    Stock name \1\      Abundance \2\   (animals/km\2\)    ESA  status \4\
                                                                                   \3\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  WNP..................           9,250           0.00001  EN
Bryde's whale......................  WNP..................          20,501            0.0003  NL
Fin whale..........................  WNP..................           9,250           0.00001  EN
Humpback whale.....................  WNP..................           1,328           0.00036  EN
Omura's whale......................  WNP..................           1,800           0.00003  NL
Sei whale..........................  NP...................           7,000            0.0029  EN
Sperm whale........................  NP...................         102,112           0.00222  EN
Pygmy sperm whale..................  WNP..................         350,553           0.00176  NL
Dwarf sperm whale..................  WNP..................         350,553            0.0043  NL
Cuvier's beaked whale..............  WNP..................          90,725           0.00374  NL
False killer whale.................  WNP..................          16,668           0.00057  NL
Melon-headed whale.................  WNP..................          36,770           0.00267  NL
Short-finned pilot whale...........  WNP..................          53,608           0.00211  NL
Risso's dolphin....................  WNP..................          83,289           0.00046  NL
Pygmy killer whale.................  WNP..................          30,214           0.00006  NL
Common bottlenose dolphin..........  WNP..................         168,791           0.00077  NL

[[Page 19472]]

 
Pantropical spotted dolphin........  WNP..................         438,064           0.01132  NL
Striped dolphin....................  WNP..................         570,038           0.00584  NL
Spinner dolphin....................  WNP..................       1,015,059           0.00187  NL
Rough-toothed dolphin..............  WNP..................         145,729           0.00185  NL
Blainville's beaked whale..........  WNP..................           8,032            0.0007  NL
Deraniyagala's beaked whale........  NP...................          22,799           0.00093  NL
Fraser's dolphin...................  CNP..................          16,992           0.00251  NL
Ginkgo-toothed beaked whale........  NP...................          22,799           0.00093  NL
Killer whale.......................  WNP..................          12,256           0.00009  NL
Longman's beaked whale.............  WNP..................           4,571           0.00025  NL
----------------------------------------------------------------------------------------------------------------
\1\ NP = north Pacific; CNP = central north Pacific; WNP = western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 12--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                      With Mission Area 10, Northern Hawaii
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                                 Density
              Species                    Stock name \1\      Abundance \2\   (animals/km\2\)    ESA  status \4\
                                                                                   \3\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  CNP..................              81             \5\NA  EN
Bryde's whale......................  Hawaii...............             798            0.0003  NL
Common minke whale.................  Hawaii...............          25,049                NA  NL
Humpback whale.....................  Hawaii DPS...........          10,103                NA  NL
Fin whale..........................  Hawaii...............              58                NA  EN
Sei whale..........................  Hawaii...............             178                NA  EN
Sperm whale........................  Hawaii...............           3,354            0.0014  EN
Pygmy sperm........................  Hawaii...............           7,138            0.0029  NL
Dwarf sperm whale..................  Hawaii...............          17,519           0.00714  NL
Cuvier's beaked whale..............  Hawaii...............           1,941            0.0008  NL
Blainville's beaked whale..........  Hawaii...............           2,338             0.001  NL
Longman's beaked whale.............  Hawaii...............           4,571            0.0019  NL
Killer whale.......................  Hawaii...............             101           0.00004  NL
False killer whale.................  Hawaii-Pelagic.......           1,540            0.0006  NL
False killer whale.................  Main Hawaiian Islands             151            0.0012  EN
                                      Insular.
False killer whale.................  Northwestern Hawaiian             617            0.0013  NL
                                      Islands.
Pygmy killer whale.................  Hawaii...............           3,433            0.0014  NL
Melon-headed whale.................  Hawaiian Islands.....           5,794            0.0012  NL
Melon-headed whale.................  Kohala Resident......             447           0.03725  NL
Short-finned pilot whale...........  Hawaii...............          12,422            0.0051  NL
Risso's dolphin....................  Hawaii...............           7,256             0.003  NL
Fraser's dolphin...................  Hawaii...............          16,992            0.0069  NL
Common bottlenose dolphin..........  Hawaii pelagic.......           5,950            0.0025  NL
Common bottlenose dolphin..........  Kauai/Niihau.........             184            0.0001  NL
Common bottlenose dolphin..........  4 Islands............             191            0.0001  NL
Common bottlenose dolphin..........  Oahu.................             743            0.0003  NL
Common bottlenose dolphin..........  Hawaii Island........             128            0.0001  NL
Pantropical spotted dolphin........  Hawaiian Pelagic.....          15,917            0.0067  NL
Pantropical spotted dolphin........  Hawaiian Island......             220            0.0067  NL
Pantropical spotted dolphin........  Oahu.................             220            0.0067  NL
Pantropical spotted dolphin........  4 Islands............             220            0.0067  NL
Striped dolphin....................  Hawaii...............          20,650            0.0084  NL
Spinner dolphin....................  Hawaii Pelagic.......           3,351            0.0008  NL
Spinner dolphin....................  Kauai/Nihau..........             601             0.007  NL
Spinner dolphin....................  Hawaiian Island......             631             0.007  NL
Spinner dolphin....................  Oahu/4 Islands.......             355             0.007  NL
Spinner dolphin....................  Kure/Midway Atoll....             260             0.007  NL
Spinner dolphin....................  Pearl and Hermes Reef             300             0.007  NL
Rough-toothed dolphin..............  Hawaii...............           6,288            0.0026  NL
Hawaiian monk seal.................  Hawaii...............           1,112           0.00001  EN
----------------------------------------------------------------------------------------------------------------
\1\ CNP = central north Pacific; WNP = western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.


[[Page 19473]]


 Table 13--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                      With Mission Area 11, Southern Hawaii
                                                  [Fall season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  CNP..................              81           0.00003  EN
Fin whale..........................  Hawaii...............              58           0.00002  EN
Bryde's whale......................  Hawaii...............             798            0.0003  NL
Common minke whale.................  Hawaii...............          25,049            0.0002  NL
Humpback whale.....................  Hawaii DPS...........          10,103           0.00089  NL
Sei whale..........................  Hawaii...............             178            0.0001  EN
Sperm whale........................  Hawaii...............           3,354            0.0014  EN
Pygmy sperm whale..................  Hawaii...............           7,138            0.0029  NL
Blainville's beaked whale..........  Hawaii...............           2,338             0.001  NL
Longman's beaked whale.............  Hawaii...............           4,571            0.0019  NL
Killer whale.......................  Hawaii...............             101           0.00004  NL
False killer whale.................  Hawaii-Pelagic.......           1,540            0.0006  NL
False killer whale.................  Main Hawaiian Island              151            0.0012  EN
                                      Insular.
Pygmy killer whale.................  Hawaii...............           3,433            0.0014  NL
Melon-headed whale.................  Hawaiian Islands.....           5,794            0.0012  NL
Melon-headed whale.................  Kohala Resident......             447           0.03725  NL
Short-finned pilot whale...........  Hawaii...............          12,422            0.0051  NL
Risso's dolphin....................  Hawaii...............           7,256             0.003  NL
Fraser's dolphin...................  Hawaii...............          16,992            0.0069  NL
Common bottlenose dolphin..........  Hawaii Pelagic.......           5,950           0.00245  NL
Common bottlenose dolphin..........  Kauai/Niihau.........             184            0.0001  NL
Common bottlenose dolphin..........  4 Islands............             191            0.0001  NL
Common bottlenose dolphin..........  Oahu.................             743            0.0003  NL
Common bottlenose dolphin..........  Hawaii Island........             128            0.0001  NL
Pantropical spotted dolphin........  Hawaiian Pelagic.....          15,917            0.0067  NL
Pantropical spotted dolphin........  Hawaii Island........             220            0.0067  NL
Pantropical spotted dolphin........  Oahu.................             220            0.0067  NL
Pantropical spotted dolphin........  4 Islands............             220            0.0067  NL
Striped dolphin....................  Hawaii...............          20,650            0.0084  NL
Spinner dolphin....................  Hawaii Pelagic.......           3,351            0.0008  NL
Spinner dolphin....................  Kauai/Niihau.........             601             0.007  NL
Spinner dolphin....................  Hawaii Island........             631             0.007  NL
Spinner dolphin....................  Oahu/4 Islands.......             355             0.007  NL
Rough toothed dolphin..............  Hawaii...............           6,288            0.0026  NL
Cuvier's beaked whale..............  Hawaii...............           1,914            0.0008  NL
Deraniyagala's beaked whale........  NP...................          22,799           0.00093  NL
Dwarf sperm whale..................  Hawaii...............          17,519           0.00714  NL
Hawaiian monk seal.................  Hawaii...............           1,400           0.00001  EN
----------------------------------------------------------------------------------------------------------------
\1\ CNP = central north Pacific; WNP = western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 14--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                               With Mission Area 12, Offshore Southern California
                                                 [Spring season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  ENP..................           1,647           0.00011  EN
Fin whale..........................  CA/OR/WA.............           3,051           0.00022  EN
Sei whale..........................  ENP..................             126           0.00009  EN
Bryde's whale......................  ENP..................          13,000           0.00001  NL
Common minke whale.................  CA/OR/WA.............             478           0.00026  NL
Humpback whale.....................  Mexico DPS...........           1,918           0.00121  T
Gray whale.........................  ENP..................          20,990           0.03090  NL
Gray whale.........................  WNP..................             140           0.00001  EN \5\
Sperm whale........................  CA/OR/WA.............           2,106           0.00337  EN
Pygmy sperm whale..................  CA/OR/WA.............             579           0.00108  NL
Stejneger's beaked whale...........  CA/OR/WA.............             694           0.00065  NL
Baird's beaked whale...............  CA/OR/WA.............             847           0.00046  NL
Cuvier's beaked whale..............  CA/OR/WA.............           6,590           0.00358  NL
Blainville's beaked whale..........  CA/OR/WA.............             694           0.00101  NL
Ginkgo-toothed beaked whale........  CA/OR/WA.............             694           0.00020  NL
Hubbs beaked whale.................  CA/OR/WA.............             694           0.00086  NL
Striped dolphin....................  CA/OR/WA.............          10,908           0.02592  NL

[[Page 19474]]

 
Perrin's beaked whale..............  CA/OR/WA.............             694           0.00088  NL
Pygmy beaked whale.................  CA/OR/WA.............             694           0.00020  NL
Killer whale (offshore)............  EP...................             240           0.00030  NL
Short-finned pilot whale...........  CA/OR/WA.............             760           0.00031  NL
Risso's dolphin....................  CA/OR/WA.............           6,272            0.0100  NL
Long-beaked common dolphin.........  CA...................         107,016           0.08591  NL
Short-beaked common dolphin........  CA/OR/WA.............         411,211           0.95146  NL
Common bottlenose dolphin            CA/OR/WA.............           1,006           0.01230  NL
 (offshore).
Pacific white-sided dolphin........  CA/OR/WA.............          26,930           0.21549  NL
Northern right whale dolphin.......  CA/OR/WA.............          21,332           0.13352  NL
Dall's porpoise....................  CA/OR/WA.............          42,000           0.02184  NL
Guadalupe fur seal.................  Mexico...............           7,408           0.00387  T
Northern fur seal..................  California...........          14,050           0.01775  NL
California sea lion................  US (Pacific                   296,750           0.33596  NL
                                      Temperate).
Harbor seal........................  California...........          30,968           0.02033  NL
Northern elephant seal.............  CA-Breeding..........         179,000           0.03222  NL
----------------------------------------------------------------------------------------------------------------
\1\ CA/OR/WA = California, Oregon, and Washington; ENP = eastern north Pacific; EP = eastern Pacific; WNP =
  western north Pacific; SMI = San Miguel Island.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ Only the western Pacific population of gray whale is endangered under the ESA.


 Table 15--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                            With Mission Area 13, Western North Atlantic Off Florida
                                                 [Winter season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Humpback whale.....................  West Indies DPS......          12,132           0.00004  NL
Common minke whale.................  Canadian East Coast..          20,174           0.00230  NL
North Atlantic right whale.........  WNA..................             476           0.00002  EN
Sperm whale........................  WNA..................           2,288           0.00083  EN
Mesoplodon spp.....................  WNA..................           7,092           0.00180  NL
Kogia spp..........................  WNA..................           3,785           0.00094  NL
Cuvier's beaked whale..............  WNA..................           6,532           0.00166  NL
Common bottlenose dolphin..........  Offshore WNA.........          77,532           0.04195  NL
Common bottlenose dolphin..........  Southern Migratory              9,173           0.00155  NL
                                      Coast.
Common bottlenose dolphin..........  Northern FL Coast....           1,219           0.00155  NL
Common bottlenose dolphin..........  Central FL Coast.....           4,895           0.00155  NL
Short-finned pilot whale...........  WNA..................          21,515           0.00616  NL
Risso's dolphin....................  WNA..................          18,250           0.00411  NL
False killer whale.................  WNA..................             442           0.00008  NL
Killer whale.......................  WNA..................              67           0.00001  NL
Short-beaked common dolphin........  WNA..................         173,486           0.00125  NL
Pantropical spotted dolphin........  WNA..................           3,333           0.00608  NL
Striped dolphin....................  WNA..................          54,807           0.00298  NL
Atlantic spotted dolphin...........  WNA..................          44,715           0.01143  NL
Spinner dolphin....................  WNA..................             262           0.00040  NL
Clymene dolphin (Stenella clymene).  WNA..................           6,086           0.02522  NL
Rough-toothed dolphin..............  WNA..................             271           0.00069  NL
----------------------------------------------------------------------------------------------------------------
\1\ WNA = western north Atlantic.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 16--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                   With Mission Area 14, Northeastern Atlantic
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  ENA..................             979           0.00002  EN
Fin whale..........................  ENA..................           9,019           0.00100  EN
Sei whale..........................  Iceland-Denmark                10,300           0.00040  EN
                                      Strait.

[[Page 19475]]

 
Common minke whale.................  Northeast Atlantic...          78,572           0.00329  NL
Humpback whale.....................  Cape Verdes and West           11,572           0.00009  EN
                                      Africa DPS.
Sperm whale........................  ENA..................           7,785           0.00077  EN
Cuvier's beaked whale..............  ENA..................           6,992           0.00700  NL
Gervais' beaked whale..............  ENA..................           6,992           0.00700  NL
Blainville's beaked whale..........  ENA..................           6,992           0.00700  NL
Sowerby's beaked whale.............  ENA..................           6,992           0.00700  NL
Northern bottlenose whale..........  ENA..................          19,538           0.00260  NL
Killer whale.......................  Northern Norway......             731           0.00001  NL
Kogia spp..........................  ENA..................           3,785           0.00079  NL
Long-finned pilot whale............  ENA..................         128,093           0.05400  NL
Risso's dolphin....................  ENA..................          18,250           0.00200  NL
Short-beaked common dolphin........  ENA..................         172,930           0.01000  NL
Common bottlenose dolphin..........  ENA..................          35,780           0.00200  NL
Striped dolphin....................  ENA..................          67,414           0.00150  NL
True's beaked whale................  ENA..................           6,992           0.00700  NL
Atlantic white-sided dolphin.......  ENA..................           3,904           0.00001  NL
White-beaked dolphin...............  ENA..................          16,536           0.01400  NL
Harbor porpoise....................  ENA..................         375,358           0.07400  NL
Harbor seal........................  NW Europe............          40,414           0.04000  NL
Gray seal..........................  NW Europe............         116,800           0.00040  NL
----------------------------------------------------------------------------------------------------------------
\1\ ENA = eastern north Atlantic.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 17--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                     With Mission Area 15, Mediterranean Sea
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Fin whale..........................  MED..................           3,583           0.00168  EN
Cuvier's beaked whale..............  Alboran Sea..........             429          0.000108  NL
Long-finned pilot whale............  ENA..................          21,515            0.0027  NL
Risso's dolphin....................  WMED.................           5,320            0.0011  NL
Short-beaked common dolphin........  WMED.................          19,428           0.00144  NL
Common bottlenose dolphin..........  WMED.................           1,676           0.00058  NL
Sperm whale........................  WMED.................             396           0.00052  EN
Striped dolphin....................  WMED.................         117,880            0.0436  NL
----------------------------------------------------------------------------------------------------------------
\1\ ENA = eastern north Atlantic; MED = Mediterranean; WMED = western Mediterranean.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 18--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                        With Mission Area 16, Arabian Sea
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  NIND.................           3,432           0.00004  EN
Bryde's whale......................  NIND.................           9,176            0.0004  NL
Common minke whale.................  IND..................         257,500           0.00920  NL
Fin whale..........................  IND..................           1,716           0.00092  EN
Humpback whale.....................  XAR..................             200           0.00005  EN
Sperm whale........................  NIND.................          24,446           0.00877  EN
Dwarf sperm whale..................  IND..................          10,541           0.00006  NL
Cuvier's beaked whale..............  IND..................          27,272           0.00308  NL
Deraniyagala beaked whale..........  IND..................          16,867           0.00278  NL
Blainville's beaked whale..........  IND..................          16,867           0.00276  NL
Ginkgo-toothed beaked whale........  IND..................          16,867           0.00278  NL
Longman's beaked whale.............  IND..................          16,867           0.01193  NL

[[Page 19476]]

 
False killer whale.................  IND..................         144,188           0.00025  NL
Pygmy killer whale.................  IND..................          22,029           0.00141  NL
Melon-headed whale.................  IND..................          64,600           0.00931  NL
Short-finned pilot whale...........  IND..................         268,751           0.03474  NL
Risso's dolphin....................  IND..................         452,125           0.08952  NL
Fraser's dolphin...................  IND..................         151,554           0.00194  NL
Common bottlenose dolphin..........  IND..................         785,585           0.05521  NL
Pantropical spotted dolphin........  IND..................         736,575           0.00922  NL
Striped dolphin....................  IND..................         674,578           0.15196  NL
Spinner dolphin....................  IND..................         634,108           0.00718  NL
Rough-toothed dolphin..............  IND..................         156,690           0.00075  NL
Long-beaked common dolphin.........  IND..................       1,819,882           0.00013  NL
Pygmy sperm whale..................  IND..................          10,541           0.00002  NL
Killer whale.......................  IND..................          12,593           0.00737  NL
Indo-Pacific bottlenose dolphin....  IND..................           7,850           0.00055  NL
----------------------------------------------------------------------------------------------------------------
\1\ IND = Indian Ocean; NIND = northern Indian Ocean; XAR = Stock X Arabian Sea.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 19--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                        With Mission Area 17, Andaman Sea
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  NIND.................           3,432           0.00003  EN
Bryde's whale......................  NIND.................           9,176           0.00037  NL
Common minke whale.................  IND..................         257,500           0.00968  NL
Fin whale..........................  IND..................           1,716            \5\ NA  EN
Omura's whale......................  IND..................           9,176           0.00037  NL
Sperm whale........................  NIND.................          24,446           0.00107  EN
Dwarf sperm whale..................  IND..................          10,541           0.00006  NL
Pygmy sperm whale..................  IND..................          10,541           0.00001  NL
Cuvier's beaked whale..............  IND..................          27,272           0.00480  NL
Blainville's beaked whale..........  IND..................          16,867           0.00094  NL
Ginkgo-toothed beaked whale........  IND..................          16,867           0.00097  NL
Longman's beaked whale.............  IND..................          16,867           0.00459  NL
Killer whale.......................  IND..................          12,593           0.00730  NL
False killer whale.................  IND..................         144,188           0.00024  NL
Fraser's dolphin...................  IND..................         151,554            0.0018  NL
Pygmy killer whale.................  IND..................          22,029           0.00125  NL
Melon-headed whale.................  IND..................          64,600           0.00878  NL
Short-finned pilot whale...........  IND..................         268,751           0.03543  NL
Risso's dolphin....................  IND..................         452,125           0.09173  NL
Long-beaked common dolphin.........  IND..................       1,819,882           0.00010  NL
Common bottlenose dolphin..........  IND..................         785,585           0.07261  NL
Indo-Pacific bottlenose dolphin....  IND..................           7,850           0.00073  NL
Pantropical spotted dolphin........  IND..................         736,575           0.00829  NL
Striped dolphin....................  IND..................         674,578           0.14123  NL
Spinner dolphin....................  IND..................         634,108           0.00701  NL
Rough-toothed dolphin..............  IND..................         156,690           0.00077  NL
Deraniyagala beaked whale..........  IND..................          16,867           0.00097  NL
----------------------------------------------------------------------------------------------------------------
\1\ IND = Indian Ocean; NIND = northern Indian Ocean.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.


[[Page 19477]]


 Table 20--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                       With Mission Area 18, Panama Canal
                                                 [Winter season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  ENP..................           1,647           0.00008  EN
Bryde's whale......................  ETP..................          13,000            0.0003  NL
Common minke whale.................  ETP..................             478           0.00031  NL
Fin whale..........................  ENP..................             832            \5\ NA  EN
Humpback whale.....................  Central America DPS..           6,000           0.00001  EN
Sperm whale........................  ETP..................          22,700            0.0047  EN
Kogia spp..........................  ETP..................          11,200             0.014  NL
Cuvier's beaked whale..............  ETP..................          20,000           0.00058  NL
Blainville's beaked whale..........  ETP..................          25,300           0.00225  NL
Ginkgo-toothed beaked whale........  ETP..................          25,300            0.0016  NL
Longman's beaked whale.............  ETP..................          25,300           0.00225  NL
Pygmy beaked whale.................  ETP..................          25,300           0.00225  NL
Killer whale.......................  ETP..................           8,500           0.00015  NL
False killer whale.................  ETP..................          39,800            0.0004  NL
Pygmy killer whale.................  ETP..................          38,900            0.0014  NL
Melon-headed whale.................  ETP..................          45,400           0.00313  NL
Short-finned pilot whale...........  ETP..................         160,200           0.01813  NL
Risso's dolphin....................  ETP..................         110,457           0.01781  NL
Short-beaked common dolphin........  ETP..................       3,127,203             0.005  NL
Fraser's dolphin...................  ETP..................         289,300             0.001  NL
Common bottlenose dolphin..........  ETP..................         335,834            0.0375  NL
Pantropical spotted dolphin........  NEOP.................         640,000            0.0375  NL
Striped dolphin....................  ETP..................         964,362           0.08125  NL
Spinner dolphin....................  Eastern..............         450,000           0.01875  NL
Rough-toothed dolphin..............  ETP..................         107,633           0.00488  NL
Mesoplodon spp.....................  ETP..................          25,300           0.00225  NL
Deraniyagala beaked whale..........  ETP..................          25,300           0.00225  NL
----------------------------------------------------------------------------------------------------------------
\1\ ETP = eastern tropical Pacific; ENP = eastern northern Pacific; NEOP = northeastern offshore Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.


 Table 21--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                  With Mission Area 19, Northeastern Australia
                                                 [Spring season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  WSP..................           9,250           0.00001  EN
Fin whale..........................  WSP..................           9,250            0.0002  EN
Bryde's whale......................  WSP..................          20,501            0.0006  NL
Common minke whale.................  WSP..................          25,049            0.0044  EN
Humpback whale.....................  East Australia DPS...          14,500           0.00089  NL
Omura's whale......................  WSP..................           1,800           0.00006  NL
Sei whale..........................  WSP..................           7,000            0.0006  EN
Sperm whale........................  WSP..................         102,112           0.00123  EN
Cuvier's beaked whale..............  WSP..................          90,725            0.0054  NL
Blainville's beaked whale..........  WSP..................           8,032            0.0005  NL
Ginkgo-toothed beaked whale........  WSP..................          22,799            0.0005  NL
Longman's beaked whale.............  WSP..................           4,571           0.00025  NL
Kogia spp..........................  WSP..................         350,553            0.0031  NL
Killer whale.......................  WSP..................          12,256           0.00009  NL
False killer whale.................  WSP..................          16,668            0.0029  NL
Pygmy killer whale.................  WSP..................          30,214            0.0021  NL
Melon-headed whale.................  WSP..................          36,770           0.00428  NL
Risso's dolphin....................  WSP..................          83,289            0.0106  NL
Short-beaked common dolphin........  WSP..................       3,286,163            0.0562  NL
Fraser's dolphin...................  WSP..................         220,789            0.0069  NL
Common bottlenose dolphin..........  WSP..................         168,791            0.0146  NL
Pantropical spotted dolphin........  WSP..................         438,064            0.0137  NL
Striped dolphin....................  WSP..................         570,038            0.0329  NL
Spinner dolphin....................  WSP..................       1,015,059           0.00083  NL
Pilot whales.......................  WSP..................          53,608            0.0153  NL

[[Page 19478]]

 
Rough-toothed dolphin..............  WSP..................         145,729            0.0059  NL
----------------------------------------------------------------------------------------------------------------
\1\ GVEA = group V east Australia; WSP = western south Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 22--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                  With Mission Area 20, Northwestern Australia
                                                 [Winter season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  SIND.................           1,657            \5\ NA  EN
Fin whale..........................  SIND.................          38,185           0.00001  EN
Bryde's whale......................  SIND.................          13,854           0.00032  NL
Antarctic minke whale..............  ANT..................          90,000                NA  NL
Common minke whale.................  IND..................         257,500                NA  NL
Humpback whale.....................  Western Australia DPS          13,640                NA  NL
Omura's whale......................  IND..................          13,854           0.00032  NL
Sei whale..........................  IND..................          13,854           0.00001  EN
Blainville's beaked whale..........  IND..................          16,867           0.00083  NL
Common bottlenose dolphin..........  IND..................           3,000           0.03630  NL
Cuvier's beaked whale..............  IND..................          76,500           0.00399  NL
Dwarf sperm whale..................  IND..................          10,541           0.00004  NL
False killer whale.................  IND..................         144,188           0.00020  NL
Fraser's dolphin...................  IND..................         151,554           0.00145  NL
Killer whale.......................  IND..................          12,593           0.00585  NL
Longman's beaked whale.............  IND..................          16,867           0.00393  NL
Melon-headed whale.................  IND..................          64,600           0.00717  NL
Pantropical spotted dolphin........  IND..................         736,575           0.00727  NL
Pygmy killer whale.................  IND..................          22,029           0.00100  NL
Risso's dolphin....................  IND..................         452,125           0.07152  NL
Rough-toothed dolphin..............  IND..................         156,690           0.00059  NL
Short-finned pilot whale...........  IND..................         268,751           0.02698  NL
Southern bottlenose whale..........  IND..................         599,300           0.00083  NL
Spade-toothed beaked whale.........  IND..................          16,867           0.00083  NL
Sperm whale........................  SIND.................          24,446           0.00096  EN
Spinner dolphin....................  IND..................         634,108           0.00561  NL
Striped dolphin....................  IND..................         674,578           0.12018  NL
----------------------------------------------------------------------------------------------------------------
\1\ ANT = Antarctic; SIND = southern Indian Ocean; IND = Indian Ocean.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.


 Table 23--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                    With Mission Area 21, Northeast of Japan
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  WNP..................           9,250            \5\ NA  EN
Common minke whale.................  WNP ``O''............          25,049            0.0022  NL
Fin whale..........................  WNP..................           9,250            0.0002  EN
Humpback whale.....................  WNP..................           1,328           0.00050  EN
North Pacific right whale..........  WNP..................             922           0.00001  EN
Sei whale..........................  NP...................           7,000           0.00029  EN
Western North Pacific gray whale...  Western DPS..........             140           0.00001  EN
Baird's beaked whale...............  WNP..................           8,000            0.0029  NL
Cuvier's beaked whale..............  WNP..................          90,725            0.0054  NL
Dall's porpoise....................  WNP..................         173,638            0.0650  NL
Killer whale.......................  WNP..................          12,256            0.0036  NL
Pacific white-sided dolphin........  NP...................         931,000            0.0048  NL
Short-beaked common dolphin........  WNP..................       3,286,163            0.0863  NL

[[Page 19479]]

 
Sperm whale........................  NP...................         102,112            0.0022  EN
Stejneger's beaked whale...........  WNP..................           8,000            0.0005  NL
Northern fur seal..................  Western Pacific......         503,609           0.01378  NL
Ribbon seal........................  NP...................          61,100            0.0452  NL
Spotted seal.......................  Bering Sea DPS.......         460,268            0.2770  NL
Steller sea lion...................  West-Asian stock and           62,218           0.00001  EN
                                      Western DPS.
----------------------------------------------------------------------------------------------------------------
\1\ IND = Indian Ocean; NP = northern Pacific; WNP = western north Pacific; ENP = eastern north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.


 Table 24--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                  With Mission Area 22, Southern Gulf of Alaska
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  ENP..................           1,647           0.00051  EN
Common minke whale.................  AK...................           1,233            0.0006  NL
Eastern North Pacific gray whale...  ENP..................          20,990           0.00019  NL
Fin whale..........................  AK/NE Pacific........           1,368           0.00049  EN
Humpback whale.....................  Hawaii DPS...........          10,103           0.00050  NL
                                     Mexico DPS...........                                    T
                                     WNP DPS..............                                    EN
North Pacific right whale..........  ENP..................              31           0.00003  EN
Sei whale..........................  ENP..................             126           0.00007  EN
Baird's beaked whale...............  AK...................             847            0.0004  NL
Cuvier's beaked whale..............  AK...................           6,590           0.00245  NL
Dall's porpoise....................  AK...................         173,638           0.07214  NL
Killer whale.......................  ENP AK resident......           2,347             0.005  NL
Killer whale.......................  ENP Gulf of AK,                   587           0.00021  NL
                                      Aleutian Islands,
                                      and Bering Sea
                                      Transient.
Pacific white-sided dolphin........  NP...................          26,880            0.0208  NL
Sperm whale........................  NP...................         102,112           0.00127  EN
Stejneger's beaked whale...........  AK...................             694           0.00084  NL
Northern elephant seal.............  California Breeding..         179,000            0.0038  NL
Northern fur seal..................  EP...................         648,534           0.03211  NL
Ribbon seal........................  AK...................         184,000           0.00001  NL
Steller sea lion...................  Eastern DPS..........          60,131           0.01085  NL
Steller sea lion...................  Western DPS..........          49,497           0.01085  EN
----------------------------------------------------------------------------------------------------------------
\1\ IND = Indian Ocean; NP = northern Pacific; ENP = eastern north Pacific; AK = Alaska.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 25--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                 With Mission Area 23, Southern Norwegian Basin
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  ENA..................             979           0.00001  EN
Common minke whale.................  Northeast Atlantic...          78,572           0.03206  NL
Fin whale..........................  North-West Norway....           6,409           0.00157  EN
Humpback whale.....................  Cape Verdes-NW Africa          11,572           0.00009  EN
                                      DPS.                                                    NL
                                     West Indies DPS......
Sei whale..........................  Iceland-Denmark                10,300           0.00001  EN
                                      Strait.
Atlantic white-sided dolphin.......  ENA..................           3,904           0.00001  NL
Cuvier's beaked whale..............  ENA..................           6,992             0.011  NL
Harbor porpoise....................  ENA..................         375,358             0.074  NL
Killer whale.......................  Northern Norway......             731           0.00001  NL

[[Page 19480]]

 
Long-finned pilot whale............  ENA..................         128,093             0.054  NL
Northern bottlenose dolphin........  ENA..................          19,538            0.0026  NL
Sowerby's beaked whale.............  ENA..................           6,992             0.011  NL
Sperm whale........................  ENA..................           7,785            0.0049  EN
White-beaked dolphin...............  ENA..................          16,536             0.011  NL
Hooded seal........................  West Ice.............          84,020           0.00811  NL
----------------------------------------------------------------------------------------------------------------
\1\ ENA = eastern north Atlantic.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 26--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                       With Mission Area 24, Western North Atlantic off Virginia/Maryland
                                                 [Summer season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Common minke whale.................  Canadian East Coast..          20,741           0.00013  NL
Fin whale..........................  WNA..................           1,618           0.00075  EN
Humpback whale.....................  West Indies DPS......          12,312           0.00006  NL
North Atlantic right whale.........  WNA..................             476          <0.00001  NL
Atlantic spotted dolphin...........  WNA..................          44,715           0.09630  NL
Clymene dolphin....................  WNA..................           6,086           0.01424  NL
Common bottlenose dolphin..........  Offshore WNA.........          77,532           0.04241  NL
                                     Northern Migratory             11,548           0.00236  NL
                                      Coastal.
                                     Southern Migratory              9,173           0.00236  NL
                                      Coastal.
Cuvier's beaked whale..............  WNA..................           6,532           0.00878  NL
False killer whale.................  WNA..................             442           0.00008  NL
Killer whale.......................  WNA..................              67           0.00001  NL
Kogia spp..........................  WNA..................           3,785           0.00079  NL
Mesoplodon spp.....................  WNA..................           7,092           0.00954  NL
Pantropical spotted dolphin........  WNA..................           3,333           0.00515  NL
Risso's dolphin....................  WNA..................          18,250           0.02202  NL
Rough-toothed dolphin..............  WNA..................             271           0.00060  NL
Short-beaked common dolphin........  WNA..................         173,486           0.07284  NL
Short-finned pilot whale...........  WNA..................          21,515           0.02215  NL
Sperm whale........................  WNA..................           2,288           0.01274  EN
Spinner dolphin....................  WNA..................             262           0.00034  NL
Striped dolphin....................  WNA..................          54,807           0.13345  NL
----------------------------------------------------------------------------------------------------------------
\1\ WNA = western north Atlantic.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 27--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                       With Mission Area 25, Labrador Sea
                                                 [Winter season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Blue whale.........................  WNA..................             440           0.00002  EN
Common minke whale.................  Canadian East Coast..          20,741           0.00013  NL
Fin whale..........................  Canadian East Coast..           1,352           0.00005  EN
Humpback whale.....................  West Indies DPS......          12,312           0.00019  NL
North Atlantic right whale.........  WNA..................             476          <0.00001  EN
Sei whale..........................  Labrador Sea.........             965           0.00002  EN
Atlantic white-sided dolphin.......  Labrador Sea.........          24,422           0.00200  NL
Harbor porpoise....................  Newfoundland.........           3,326           0.00160  NL
Killer whale.......................  WNA..................              67           0.00001  NL
Long-finned pilot whale............  Canadian East Coast..           6,134           0.00370  NL
Northern bottlenose dolphin........  Davis Strait.........              50           0.00001  NL
Short-beaked common dolphin........  WNA..................         173,486           0.00100  NL
Sowerby's beaked whale.............  WNA..................              50           0.00001  NL
Sperm whale........................  WNA..................           2,288           0.00127  EN

[[Page 19481]]

 
White-beaked dolphin...............  Canadian East Coast..          15,625           0.00077  NL
Arctic ringed seal.................  Arctic...............         787,000           0.07300  NL
Harp seal..........................  WNA..................       7,411,000           0.07043  NL
Hooded seal........................  WNA..................         592,100            0.0081  NL
----------------------------------------------------------------------------------------------------------------
\1\ WNA = western north Atlantic.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 28--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                      With Mission Area 26, Sea of Okhotsk
                                                 [Spring season]
----------------------------------------------------------------------------------------------------------------
                                                                            Density (animals/
              Species                    Stock name \1\      Abundance \2\     km\2\) \3\       ESA status \4\
----------------------------------------------------------------------------------------------------------------
Bowhead whale......................  Okhotsk Sea..........             247           0.00001  EN
Common minke whale.................  WNP ``O''............          25,049           0.01727  NL
                                     WNP ``J''............             893           0.00062  EN
Fin whale..........................  WNP..................           9,250            0.0002  EN
Humpback whale.....................  WNP DPS..............           1,328           0.00089  EN
North Pacific right whale..........  WNP..................             922            \5\ NA  EN
Western North Pacific gray whale...  Western DPS..........             140                NA  EN
Baird's beaked whale...............  WNP..................           8,000            0.0015  NL
Beluga whale.......................  Okhotsk Sea..........          12,226            0.0071  NL
Cuvier's beaked whale..............  WNP..................          90,725            0.0054  Nl
Dall's porpoise....................  WNP dalli-trype......         111,402           0.18031  NL
                                     WNP truei-type.......         101,173           0.16375  NL
Harbor porpoise....................  WNP..................          31,046            0.0190  NL
Killer whale.......................  Okhotsk-Kamchatka-             12,256            0.0036  NL
                                      Western Aleutians
                                      Transient.
Pacific white-sided dolphin........  NP...................         931,000            0.0048  NL
Sperm whale........................  NP...................         102,112            0.0022  EN
Northern fur seal..................  Western Pacific......         503,609           0.08031  NL
Okhotsk ringed seal................  Okhotsk..............         676,000           0.23881  T
Pacific bearded seal...............  Okhotsk DPS..........         200,000           0.01174  T
Ribbon seal........................  Sea of Okhotsk.......         124,000            0.0904  NL
Spotted seal.......................  Sea of Okhotsk DPS...         180,000            0.2770  NL
Steller sea lion...................  Western DPS..........          82,516           0.02189  EN
----------------------------------------------------------------------------------------------------------------
\1\ WNP = western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not
  expected to occur during the season modeled.

    Information on how the density and stock/abundance estimates were 
derived for the selected mission sites is in the Navy's application. 
These data are derived from the best available, published source 
documentation, and provide general area information for each mission 
area with species-specific information on the animals that could occur 
in that area, including estimates for their stock abundance and 
density. The Navy developed the abundance and density estimates by 
first using estimates from line-transect surveys that occurred in or 
near each of the 26 model sites (e.g., Barlow, 2006). However, density 
estimates require more sophisticated sampling and analysis and were not 
always available for each species at all sites. When density estimates 
were not available from a survey in the operating area, the Navy 
extrapolated density estimates from a region with similar oceanographic 
characteristics to that operating area. For example, the eastern 
tropical Pacific has been extensively surveyed and provides a 
comprehensive understanding of marine mammals in temperate oceanic 
waters (Ferguson and Barlow, 2001, 2003). Density estimates for some 
mission areas/model sites were also derived from the Navy's Marine 
Species Density Database (DoN, 2016b). In addition, density estimates 
are usually not available for rare marine mammal species or for those 
that have been newly defined (e.g., the Deraniyagala's beaked whale). 
For these species, the lowest density estimate of 0.0001 animals/square 
kilometer (0.0001 animals/km\2\) was used in the take analysis to 
reflect the low probability of occurrence in a specific SURTASS LFA 
sonar mission area. Further, the Navy pooled density estimates for 
species of the same genus if sufficient data are not available to 
compute a density for individual species or the species are difficult 
to distinguish at sea, which is often the case for pilot whales and 
beaked whales, as well as the pygmy and dwarf sperm whales. Density 
estimates are available for these species

[[Page 19482]]

groups rather than the individual species.
    The Navy provides detailed descriptions of the distribution, 
abundance, diving behavior, life history, and hearing vocalization 
information for each affected marine mammal species with confirmed or 
possible occurrence within SURTASS LFA sonar operational areas in 
section 4 (pages 4-1 through 4-71) of the application, which is 
available online at https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications).
    Although not repeated in this document, NMFS has reviewed these 
data, determined them to be the best available scientific information 
for the proposed rulemaking, and considers this information part of the 
administrative record for this action. Additional information is 
available in NMFS' Marine Mammal Stock Assessment Reports, which may be 
viewed at https://www.nmfs.noaa.gov/pr/sars/species.htm. NMFS refers the 
public to Table 3-2 (pages 3-9 through 3-36) of the Navy's application 
for literature references associated with abundance and density 
estimates presented in these tables.

Brief Background on Sound, Marine Mammal Hearing, and Vocalization

Underwater Sound

    An understanding of the basic properties of underwater sound is 
necessary to comprehend many of the concepts and analyses presented in 
this document. Sound is a wave of pressure variations propagating 
through a medium (for the sonar considered in this proposed rulemaking, 
the medium is seawater). Pressure variations are created by compressing 
and relaxing the medium. Sound measurements can be expressed in two 
forms: Intensity and pressure. Acoustic intensity is the average rate 
of energy transmitted through a unit area in a specified direction and 
is expressed in watts per square meter (W/m\2\). Acoustic intensity is 
rarely measured directly, it is derived from ratios of pressures; the 
standard reference pressure for underwater sound is 1 [mu]Pa 
(Richardson et al., 1995).
    Acousticians have adopted a logarithmic scale for sound 
intensities, which is denoted in dB. The logarithmic nature of the 
scale means that each 10 dB increase is a ten-fold increase in power 
(e.g., 20 dB is a 100-fold increase, 30 dB is a 1,000-fold increase). 
Humans perceive a 10-dB increase in noise as a doubling of sound level, 
or a 10-dB decrease in noise as a halving of sound level. Sound 
pressure level or SPL implies a decibel measure and a reference 
pressure that is used as the denominator of the ratio.
    Sound frequency is measured in cycles per second, referred to as 
Hertz (Hz), and is analogous to musical pitch; high-pitched sounds 
contain high frequencies and low-pitched sounds contain low 
frequencies. Natural sounds in the ocean span a large range of 
frequencies: From earthquake noise at five Hz to harbor porpoise clicks 
at 150,000 Hz (150 kilohertz (kHz)). These sounds are so low or so high 
in pitch that humans cannot even hear them; acousticians call these 
infrasonic (typically below 20 Hz, which is considered the low 
frequency bound of human hearing) and ultrasonic (typically above 
20,000 Hz, which is considered the upper bound of human hearing) 
sounds, respectively. A single sound may be made up of multiple 
frequencies. Sounds made up of only a small range of frequencies are 
called narrowband, and sounds with a broad range of frequencies are 
called broadband. Explosives are an example of a broadband sound source 
and tactical military sonars are an example of a narrowband sound 
source.

Metrics Used in This Document

    This section includes a brief explanation of the sound measurements 
frequently used in the discussions of acoustic effects in this 
document.
Sound Pressure Level
    Sound pressure level (SPL) is expressed as the ratio of a measured 
sound pressure and a reference level. The commonly used reference 
pressure level in underwater acoustics is 1 [mu]Pa, and the units for 
SPLs are decibels (dB) re: 1 [mu]Pa. SPL (in dB) = 20 log (pressure/
reference pressure). SPL is an instantaneous measurement and can be 
expressed as the peak, the peak-peak (p-p), or the root mean square 
(rms). SPL does not directly take the duration of exposure to a sound 
into account, though it should be noted that the duration over which 
the root mean square pressure is averaged since it influences the 
result. Root mean square pressure, which is the square root of the 
arithmetic average of the squared instantaneous pressure values (Urick, 
1983), is typically used in discussions of behavioral effects of sounds 
on vertebrates in part because behavioral effects, which often result 
from auditory cues, may be better expressed through averaged units than 
by peak pressures. All references to SPL in this document refer to the 
root mean square unless otherwise noted.
Cumulative Sound Exposure Level
    Sound exposure level (SEL; represented as dB re 1 [mu]Pa\2\-s) 
represents the total energy contained within a pulse, and considers 
both exposure level and duration of exposure. The NMFS 2016 Acoustic 
Technical Guidance builds upon the foundation provided by Southall et 
al. (2007), while incorporating new information available since 
development of that work (e.g., Finneran, 2015). Southall et al. (2007) 
recommended specific thresholds under the dual metric approach (i.e., 
peak SPL (SPLpk) and cumulative SEL (SELcum)), 
and that marine mammals be divided into hearing groups based on 
measured or estimated hearing ranges. The premise of the dual criteria 
approach is that, while there is no definitive answer to the question 
of which acoustic metric is most appropriate for assessing the 
potential for auditory injury, both the exposure level and duration of 
received signals are important to an understanding of the potential for 
injury. Therefore, peak SPL is used to define a pressure criterion 
above which auditory injury is predicted to occur, regardless of 
exposure duration (i.e., any single exposure at or above this level is 
considered to cause auditory injury), and the SELcum metric 
is used to account for the total energy received over the specified 
duration of sound exposure (i.e., metric accounts for both received 
level and duration of exposure) (Southall et al., 2007; NMFS, 2016). As 
SPLpk is applicable to impulsive noise, it is not applicable 
to SURTASS LFA sonar and is not discussed further here. Note that 
SELcum acoustic thresholds also incorporate marine mammal 
auditory weighting functions. NMFS (2016) recommends 24 hours as a 
maximum accumulation period relative to SELcum thresholds. 
For further discussion of auditory weighting functions and their 
application or metrics associated with evaluating noise-induced hearing 
loss, please see NMFS (2016). Table 29 displays auditory impact 
thresholds provided by NMFS (2016).

[[Page 19483]]



   Table 29--TTS and PTS Onset Thresholds for Non-Impulsive Sounds \1\
------------------------------------------------------------------------
                                         Cumulative        Cumulative
                                       sound exposure    sound exposure
            Hearing group               level for TTS     level for PTS
                                          \1\ (dB)          \1\ (dB)
------------------------------------------------------------------------
Low-frequency cetaceans.............               179               199
Mid-frequency cetaceans.............               178               198
High-frequency cetaceans............               153               173
Phoicid pinnipeds (PW) (Underwater).               181               201
Otariid pinnipeds (OW) (Underwater).               199              219
------------------------------------------------------------------------
\1\ Referenced to 1 [mu]Pa\2\s; weighted according to appropriate
  auditory weighting function.

Single Ping Equivalent (SPE)
    To model potential behavioral impacts to marine animals from 
exposure to SURTASS LFA sonar sound, the Navy has developed a 
methodology to estimate the total exposure of modeled animals exposed 
to multiple pings over an extended period of time. The Navy's acoustic 
model analyzes the following components: (1) The LFA sonar source 
modeled as a point source, with an effective source level (SL) in dB 
re: 1 [mu]Pa at 1 m (SPL); (2) a 60-sec duration signal; and (3) a beam 
pattern that is correct for the number and spacing of the individual 
projectors (source elements). This source model, when combined with the 
three-dimensional transmission loss (TL) field generated by the 
Parabolic Equation (PE) acoustic propagation model, defines the 
received level (RL) (in SPL) sound field surrounding the source for a 
60-sec LFA sonar signal (i.e., the SPE metric accounts for received 
level and exposure from multiple pings). To estimate the total exposure 
of animals exposed to multiple pings, the Navy models the RLs for each 
modeled location and any computer-simulated marine mammals (animats) 
within the location, records the exposure history of each animat, and 
generates a SPE value. Thus, the Navy can model the SURTASS LFA sound 
field, providing a four-dimensional (position and time) representation 
of a sound pressure field within the marine environment and estimates 
of an animal's exposure to sound over a period of 24 hours.
    Figure 2 shows the Navy calculation that converts SPL values to SPE 
values in order to estimate impacts to marine mammals from SURTASS LFA 
sonar transmissions. For a more detailed explanation of the SPE 
calculations, NMFS refers the public to Appendix B of the Navy's 2016 
DSEIS/SOEIS.
[GRAPHIC] [TIFF OMITTED] TP27AP17.001

Marine Mammal Hearing

    Cetaceans have an auditory anatomy that follows the basic mammalian 
pattern, with some changes to adapt to the demands of hearing in the 
sea. The typical mammalian ear is divided into an outer ear, middle 
ear, and inner ear. The outer ear is separated from the inner ear by a 
tympanic membrane, or eardrum. In terrestrial mammals, the outer ear, 
eardrum, and middle ear transmit airborne sound to the inner ear, where 
the sound waves are propagated through the cochlear fluid. Since the 
impedance of water (i.e., the product of density and sound speed) is 
close to that of the tissues of a cetacean, the outer ear is not 
required to transduce sound energy as it does when sound waves travel 
from air to fluid (inner ear). Sound waves traveling through the inner 
ear cause the basilar membrane to vibrate. Specialized cells, called 
hair cells, respond to the vibration and produce nerve pulses that are 
transmitted to the central nervous system. Acoustic energy causes the 
basilar membrane in the cochlea to vibrate. Sensory cells at different 
positions along the basilar membrane are excited by different 
frequencies of sound (Pickles, 1998).
    When considering the influence of various kinds of sound on the 
marine environment, it is necessary to understand that different kinds 
of marine life are sensitive to different frequencies of sound. Based 
on available behavioral data, audiograms derived using auditory evoked 
potential (AEP) techniques, anatomical modeling, and other data, 
Southall et al. (2007) designated ``functional hearing groups'' for 
marine mammals and estimated the lower and upper frequencies of 
functional hearing (i.e., the frequencies that the species can actually 
hear) of these groups as follows:
     Low frequency (LF) cetaceans (13 species of mysticetes): 
Southall et al. (2007) estimates that functional hearing occurs between 
approximately seven Hz and 22 kHz;
     Mid-frequency (MF) cetaceans (32 species of dolphins, six 
species of larger toothed whales, and 19 species of beaked and 
bottlenose whales): Southall et al. (2007) estimates that functional 
hearing occurs between approximately 150 Hz and 160 kHz;
     High frequency (HF) cetaceans (eight species of true 
porpoises, six species of river dolphins, Kogia, the franciscana, and 
four species of cephalorhynchids): Southall et al. (2007) estimates 
that functional hearing

[[Page 19484]]

occurs between approximately 200 Hz and 180 kHz.
     Pinnipeds in Water: Southall et al. (2007) estimates that 
functional hearing occurs between approximately 75 Hz and 75 kHz, with 
the greatest sensitivity between approximately 700 Hz and 20 kHz.
    In August 2016 NMFS released its Technical Guidance for Assessing 
the Effects of Anthropogenic Sound on Marine Mammal Hearing (NMFS 2016 
Acoustic Technical Guidance), which modified the hearing groups 
proposed in Southall et al. (2007) in the following ways:
     Division of pinnipeds into phocids in water (PW) and 
otariids in water (OW) hearing groups; and
     Re-Categorization of two species of dolphins (hourglass 
[Lagenorhynchus cruiger] and Peale's [L. australis]) from mid-frequency 
(MF) to high-frequency (HF) hearing group.
    Therefore, under the new NMFS 2016 Acoustic Technical Guidance, 
there are five marine mammal hearing group categories, with associated 
generalized hearing ranges as shown in Table 30 (note that animals are 
less sensitive to sounds at the outer edge of their generalized hearing 
range and most sensitive to sounds of frequencies within a smaller 
range somewhere in the middle of their functional hearing range).

                 Table 30--Marine Mammal Hearing Groups
                              [NMFS, 2016]
------------------------------------------------------------------------
            Hearing group                Generalized hearing range \1\
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans           150 Hz to 160 kHz.
 (dolphins, 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 underwater (PW)       50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds underwater (OW)      60 Hz to 39 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
\1\ 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 ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al. 2007) and PW pinniped (approximation).

Marine Mammal Hearing Groups and LFA Sonar

    Baleen (mysticete) whales (members of the LF hearing group) have 
inner ears that appear to be specialized for low-frequency hearing. 
Conversely, most odontocetes (i.e., dolphins and porpoises) have inner 
ears that are specialized to hear mid and high frequencies. Pinnipeds, 
which lack the highly specialized active biosonar systems of 
odontocetes, have inner ears that are specialized to hear a broad range 
of frequencies in water (Southall et al., 2007). Based on an extensive 
suite of reported laboratory measurements (DoN, 2001, Ketten, 1997, 
Southall et al., 2007), the LFA sound source is below the range of best 
hearing sensitivity for MF and HF odontocete and pinnipeds in water 
hearing specialists (Clark and Southall, 2009).

Marine Mammal Vocalization

    Marine mammal vocalizations often extend both above and below the 
range of human hearing (higher than 20 kHz and lower than 20 Hz; 
Research Council, 2003). Measured data on the hearing abilities of 
cetaceans are sparse, particularly for the larger cetaceans such as the 
baleen whales. The auditory thresholds of some of the smaller 
odontocetes have been determined in captivity. It is generally believed 
that cetaceans should at least be sensitive to the frequencies of their 
own vocalizations. Comparisons of the anatomy of cetacean inner ears 
and models of the structural properties and the response to vibrations 
of the ear's components in different species provide an indication of 
likely sensitivity to various sound frequencies. Thus, the ears of 
small toothed whales are optimized for receiving high-frequency sound, 
while baleen whale inner ears are best suited for low frequencies, 
including to infrasonic frequencies (Ketten, 1992; 1997; 1998).
    Baleen whale (i.e., mysticete) vocalizations are composed primarily 
of frequencies below one kHz, and some contain fundamental frequencies 
as low as 16 Hz (Watkins et al., 1987; Richardson et al., 1995; Rivers, 
1997; Moore et al., 1998; Stafford et al., 1999; Wartzok and Ketten, 
1999) but can be as high as 24 kHz (humpback whale; Au et al., 2006). 
Clark and Ellison (2004) suggested that baleen whales use low frequency 
sounds not only for long-range communication, but also as a simple form 
of echo ranging, using echoes to navigate and orient relative to 
physical features of the ocean. Information on auditory function in 
mysticetes is limited. Sensitivity to low frequency sound by baleen 
whales has been inferred from observed vocalization frequencies, 
observed reactions to playback of sounds, and anatomical analyses of 
the auditory system. Although there is apparently much variation, the 
source levels of most baleen whale vocalizations lie in the range of 
150-190 dB re: 1 [mu]Pa at 1 m. Low-frequency vocalizations made by 
baleen whales and their corresponding auditory anatomy suggest that 
they have good low-frequency hearing (Ketten, 2000), although specific 
data on sensitivity, frequency or intensity discrimination, or 
localization abilities are lacking. Marine mammals, like all mammals, 
have typical U-shaped audiograms that begin with relatively low 
sensitivity (high threshold) at some specified low frequency with 
increased sensitivity (low threshold) to a species-specific optimum 
followed by a generally steep rise at higher frequencies (high 
threshold) (Fay, 1988).
    Toothed whales (i.e., odontocetes) produce a wide variety of 
sounds, which include species-specific broadband ``clicks'' with peak 
energy between 10 and 200 kHz, individually variable ``burst pulse'' 
click trains, and constant frequency or frequency-modulated (FM) 
whistles ranging from 4 to 16 kHz (Wartzok and Ketten, 1999). The 
general consensus is that the tonal vocalizations (whistles) produced 
by toothed whales play an important role in maintaining contact between 
dispersed individuals, while broadband clicks are used during 
echolocation (Wartzok and Ketten, 1999). Burst pulses have also been 
strongly implicated in communication, with some scientists suggesting 
that they play an important role in agonistic encounters (McCowan and 
Reiss, 1995), while others have proposed that they represent 
``emotive'' signals in a broader

[[Page 19485]]

sense, possibly representing graded communication signals (Herzing, 
1996). Sperm whales, however, are known to produce only clicks, which 
are used for both communication and echolocation (Whitehead, 2003). 
Most of the energy of toothed whales' social vocalizations is 
concentrated near 10 kHz, with source levels for whistles as high as 
100-180 dB re 1 [mu]Pa at 1 m (Richardson et al., 1995). No odontocete 
has been shown audiometrically to have acute hearing (less than 80 dB 
re 1 [mu]Pa at 1 m) below 500 Hz (DoN, 2001; Ketten, 1998). Sperm 
whales produce clicks, which may be used to echolocate (Mullins et al., 
1988), with a frequency range from less than 100 Hz to 30 kHz and 
source levels up to 230 dB re 1 [mu]Pa at 1 m or greater (Mohl et al., 
2000).

Potential Effects of the Specified Activity on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activities may impact marine mammals and 
their habitat. The Estimated Take of Marine Mammals section later in 
this document will include a quantitative analysis of the maximum 
percentage of the affected stocks that are expected to be taken by the 
SURTASS LFA activities, but enumeration of takes of individuals is 
completed annually when the Navy submits their application for LOAs for 
that year's mission areas. The Negligible Impact Analysis and 
Determination section will consider 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 how those impacts on individuals are likely to impact marine mammal 
species or stocks.
    The Navy has requested authorization for the incidental take of 
marine mammals that may result from upcoming use of SURTASS LFA sonar 
by a maximum of four U.S. Naval ships in certain areas of the Pacific, 
Atlantic, and Indian Oceans and the Mediterranean Sea. In addition to 
the use of LFA and HF/M3 sonar, the Navy has analyzed the potential 
impact of ship strike to marine mammals from SURTASS LFA sonar 
activities, and, in consultation with NMFS as a cooperating agency for 
the SURTASS LFA sonar 2016 DSEIS/SOEIS, has determined that take of 
marine mammals incidental to this non-acoustic component of the Navy's 
operations is not reasonably likely to occur. Therefore, the Navy has 
not requested authorization for take of marine mammals that might occur 
incidental to vessel ship strike. In this document, NMFS analyzes the 
potential effects on marine mammals from exposure to LFA and HF/M3 
sonar, but also includes some additional analysis of the potential 
impacts from vessel operations.
    NMFS' analysis of potential impacts from SURTASS LFA activities is 
outlined in the next section. NMFS will focus qualitatively on the 
different ways that SURTASS LFA sonar activities may affect marine 
mammals (some of which may not be classifiedas takes). Then, in the 
Estimated Take of Marine Mammals section, NMFS will relate the 
potential effects to marine mammals from SURTASS LFA sonar activities 
to the MMPA definitions of take, including Level A and Level B 
Harassment.
    The potential effects to marine mammals described in the following 
sections do not take into consideration the proposed mitigation and 
related monitoring measures described later in this document (see the 
Proposed Mitigation section) which, as noted, are designed to effect 
the least practicable adverse impact on affected marine mammals species 
and stocks.

Potential Effects of Exposure to SURTASS LFA Sonar Activities

    The potential effects of sound from the proposed activities 
associated with SURTASS LFA sonar might include one or more of the 
following: Behavioral changes, masking, non-auditory injury (i.e., gas 
bubble formation/rectified diffusion), and noise-induced loss of 
hearing sensitivity (more commonly called threshold shift). NMFS 
discusses these potential effects in more detail below.
    The effects of underwater noise on marine mammals are highly 
variable, and one can categorize the effects as follows (Richardson et 
al., 1995; Nowacek et al., 2007; Southall et al., 2007):
    (1) The noise may be too weak to be heard at the location of the 
animal (i.e., lower than the prevailing ambient noise level, the 
hearing threshold of the animal at relevant frequencies, or both);
    (2) The noise may be audible but not strong enough to elicit any 
overt behavioral response;
    (3) The noise may elicit behavioral reactions of variable 
conspicuousness and variable relevance to the well-being of the animal. 
These can range from temporary alert responses to active avoidance 
reactions such as vacating an area at least until the noise event 
ceases, but potentially for longer periods of time;
    (4) Upon repeated exposure, a marine mammal may exhibit diminishing 
responsiveness (habituation), disturbance effects may persist, or 
disturbance effects could increase (sensitization, or becoming more 
sensitive to exposure). Persistent disturbance and sensitization are 
more likely with sounds that are highly variable in characteristics, 
infrequent, and unpredictable in occurrence, and associated with 
situations that the animal perceives as a threat (animals are not 
likely to be exposed enough to SURTASS LFA sonar to exhibit habituation 
or increased sensitization, due to the fact that SURTASS LFA sonar is a 
mobile source operating in open water, and animals are likely to move 
away and/or would not be receiving pings in the way that small resident 
populations would receive with a stationary source);
    (5) Any anthropogenic (human-made) noise that is strong enough to 
be heard has the potential to reduce the ability of a marine mammal to 
hear natural sounds at similar frequencies (masking), including calls 
from conspecifics (i.e., an organism of the same species), and 
underwater environmental sounds such as surf noise;
    (6) If mammals remain in an area because it is important for 
feeding, breeding, or some other biologically important purpose even 
though there is a chronic exposure to noise, it is possible that there 
could be noise-induced physiological stress. This might in turn have 
negative effects on the well-being or reproduction of the animals 
involved; and
    (7) Very strong sounds have the potential to cause temporary or 
permanent reduction in hearing sensitivity, also known as threshold 
shift. In terrestrial mammals and presumably marine mammals, received 
sound levels must far exceed the animal's hearing threshold for there 
to be any temporary threshold shift (TTS) in its hearing ability. For 
transient sounds, the sound level necessary to cause TTS is inversely 
related to the duration of the sound. Received sound levels must be 
even higher for there to be the possibility of permanent hearing 
impairment. In addition, intense acoustic or explosive events (not 
relevant for this proposed activity) may cause trauma to tissues 
associated with organs vital for hearing, sound production, respiration 
and other functions. This trauma may include minor to severe 
hemorrhage.

[[Page 19486]]

Direct Physiological Effects

Threshold Shift (Noise-Induced Loss of Hearing)
    When animals exhibit reduced hearing sensitivity within their 
auditory range (i.e., sounds must be louder for an animal to detect 
them) following exposure to a sufficiently intense sound or a less 
intense sound for a sufficient duration, it is referred to as a noise-
induced threshold shift (TS). An animal can experience a temporary 
threshold shift (TTS) and/or permanent threshold shift (PTS). TTS can 
last from minutes or hours to days (i.e., there is recovery back to 
baseline/pre-exposure levels), can occur within a specific frequency 
range (i.e., an animal might only have a temporary loss of hearing 
sensitivity within a limited frequency band of its auditory range), and 
can be of varying amounts (for example, an animal's hearing sensitivity 
might be reduced by only six dB or reduced by 30 dB). PTS is permanent 
(i.e., there is incomplete recovery back to baseline/pre-exposure 
levels), but also can occur in a specific frequency range and amount as 
mentioned above for TTS.
    The following physiological mechanisms are thought to play a role 
in inducing auditory TS: Effects to sensory hair cells in the inner ear 
that reduce their sensitivity; modification of the chemical environment 
within the sensory cells; residual muscular activity in the middle ear; 
displacement of certain inner ear membranes; increased blood flow; and 
post-stimulatory reduction in both efferent and sensory neural output 
(Southall et al., 2007). The amplitude, duration, frequency, temporal 
pattern, and energy distribution of sound exposure all can affect the 
amount of associated TS and the frequency range in which it occurs. 
Generally, the amount of TS, and the time needed to recover from the 
effect, increase as amplitude and duration of sound exposure increases. 
Human non-impulsive noise exposure guidelines are based on the 
assumption that exposures of equal energy (the same SEL) produce equal 
amounts of hearing impairment regardless of how the sound energy is 
distributed in time (NIOSH, 1998). Previous marine mammal TTS studies 
have also generally supported this equal energy relationship (Southall 
et al., 2007). However, some more recent studies concluded that for all 
noise exposure situations the equal energy relationship may not be the 
best indicator to predict TTS onset levels (Mooney et al., 2009a and 
2009b; Kastak et al., 2007). These studies highlight the inherent 
complexity of predicting TTS onset in marine mammals, as well as the 
importance of considering exposure duration when assessing potential 
impacts. Generally, with sound exposures of equal energy, those that 
were quieter (lower sound pressure level (SPL)) with longer duration 
were found to induce TTS onset at lower levels than those of louder 
(higher SPL) and shorter duration. Less TS will occur from intermittent 
sounds than from a continuous exposure with the same energy (some 
recovery can occur between intermittent exposures) (Kryter et al., 
1966; Ward, 1997; Mooney et al. 2009a, 2009b; Finneran et al. 2010). 
For example, one short but loud (higher SPL) sound exposure may induce 
the same impairment as one longer but softer (lower SPL) sound, which 
in turn may cause more impairment than a series of several intermittent 
softer sounds with the same total energy (Ward, 1997). Additionally, 
though TTS is temporary, very prolonged or repeated exposure to sound 
strong enough to elicit TTS, or shorter-term exposure to sound levels 
well above the TTS threshold can cause PTS, at least in terrestrial 
mammals (Kryter, 1985; Lonsbury-Martin et al. 1987). However, in the 
case of the proposed SURTASS LFA sonar activities, animals are not 
expected to be exposed to levels high enough or durations long enough 
to result in PTS due to the nature of the activities. The potential for 
PTS becomes even more unlikely when mitigation measures are considered.
    PTS is considered auditory injury (Southall et al., 2007). 
Irreparable damage to the inner or outer cochlear hair cells may cause 
PTS; however, other mechanisms are also involved, such as exceeding the 
elastic limits of certain tissues and membranes in the middle and inner 
ears and resultant changes in the chemical composition of the inner ear 
fluids (Southall et al., 2007).
    Although the published body of scientific literature contains 
numerous theoretical studies and discussion papers on hearing 
impairments that can occur with exposure to a loud sound, only a few 
studies provide empirical information on the levels at which noise-
induced loss in hearing sensitivity occurs in nonhuman animals. The 
NMFS 2016 Acoustic Technical Guidance, which was used in the assessment 
of effects for this action, compiled, interpreted, and synthesized the 
best available scientific information for noise-induced hearing effects 
for marine mammals to derive updated thresholds for assessing the 
impacts of noise on marine mammal hearing, as noted above. For 
cetaceans, published data on the onset of TTS are limited to the 
captive bottlenose dolphin, beluga, harbor porpoise, and Yangtze 
finless porpoise (summarized in Finneran, 2015). TTS studies involving 
exposure to SURTASS LFA or other low-frequency sonar (below 1 kHz) have 
never been conducted due to logistical difficulties of conducting 
experiments with low frequency sound sources. However, there are TTS 
measurements for exposures to other LF sources, such as seismic 
airguns. Finneran et al. (2015) suggest that the potential for airguns 
to cause hearing loss in dolphins is lower than previously predicted, 
perhaps as a result of the low-frequency content of airgun impulses 
compared to the high-frequency hearing ability of dolphins. For 
pinnipeds in water, measurements of TTS are limited to harbor seals, 
elephant seals, and California sea lions (summarized in Finneran, 
2015).
    Marine mammal hearing plays a critical role in communication with 
conspecifics and in interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. Depending on the degree 
(elevation of threshold in dB), duration (i.e., recovery time), and 
frequency range of TTS, and the context in which it is experienced, TTS 
can have effects on marine mammals ranging from discountable to serious 
similar to those discussed in auditory masking, below. For example, a 
marine mammal may be able to readily compensate for a brief, relatively 
small amount of TTS in a non-critical frequency range that takes place 
during a time 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 a time when communication is critical for successful 
mother/calf interactions could have more serious impacts if it were in 
the same frequency band as the necessary vocalizations and of a 
severity that impeded communication. The fact that animals exposed to 
high levels of sound that would be expected to result in this 
physiological response would also be expected to have behavioral 
responses of a comparatively more severe or sustained nature is 
potentially more significant than simple existence of a TTS. However, 
it is important to note that TTS could occur due to longer exposures to 
sound at lower levels so that a behavioral response may not be 
elicited.
    Depending on the degree and frequency range, the effects of PTS on 
an animal could also range in severity, although it is considered 
generally more serious than TTS because it is a

[[Page 19487]]

permanent condition. Of note, reduced hearing sensitivity as a simple 
function of aging has been observed in marine mammals, as well as 
humans and other taxa (Southall et al., 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without some cost to the animal. There is no empirical 
evidence that exposure to SURTASS LFA sonar can cause PTS in any marine 
mammals, especially given the proximity to and duration that an animal 
would need to be exposed; instead the possibility of PTS has been 
inferred from studies of TTS on captive marine mammals (see Richardson 
et al., 1995).
    As stated in the Navy's DSEIS/SOEIS (section 4.2.3), results show 
that all hearing groups except LF cetaceans would need to be within 22 
ft (7 m) for an entire LFA transmission (60 seconds) to potentially 
experience PTS. A LF cetacean would need to be within 135 ft (41 m) for 
an entire LFA transmission to potentially experience PTS. Based on the 
mitigation procedures used during SURTASS LFA sonar activities, and the 
fact that animals can be expected to move away from any disturbance, 
the chances of this occurring are negligible.
Acoustically Mediated Bubble Growth
    One theoretical cause of injury to marine mammals is rectified 
diffusion (Crum and Mao, 1996), the process of increasing the size of a 
bubble by exposing it to a sound field. This process could be 
facilitated if the environment in which the ensonified bubbles exist is 
supersaturated with gas. Repetitive diving by marine mammals can cause 
the blood and some tissues to accumulate gas to a greater degree than 
is supported by the surrounding environmental pressure (Ridgway and 
Howard, 1979). The deeper and longer dives of some marine mammals 
(e.g., beaked whales) are theoretically predicted to induce greater 
supersaturation (Houser et al., 2001b). A study of repetitive diving in 
trained bottlenose dolphins found no increase in blood nitrogen levels 
or formation of bubbles (Houser et al., 2009). If rectified diffusion 
were possible in marine mammals exposed to high-level sound, conditions 
of tissue supersaturation could theoretically speed the rate and 
increase the size of bubble growth. Subsequent effects due to tissue 
trauma and emboli would presumably mirror those observed in humans 
suffering from decompression sickness.
    It is unlikely that the short duration of the SURTASS LFA sonar 
pings would be long enough to drive bubble growth to any substantial 
size, if such a phenomenon occurs. However, an alternative but related 
hypothesis has also been suggested; stable bubbles could be 
destabilized by high-level sound exposures such that bubble growth then 
occurs through static diffusion of gas out of the tissues. In such a 
scenario the marine mammal would need to be in a gas-supersaturated 
state for a long enough period of time for bubbles to become a 
problematic size. Research with ex vivo supersaturated bovine tissues 
suggests that, for a 37 kHz signal, a sound exposure of approximately 
215 dB re 1[micro]Pa would be required before microbubbles became 
destabilized and grew (Crum et al., 2005). Furthermore, tissues in the 
study were supersaturated by exposing them to pressures of 400-700 
kiloPascals for periods of hours and then releasing them to ambient 
pressures. Assuming the equilibration of gases with the tissues 
occurred when the tissues were exposed to high pressures, levels of 
supersaturation in the tissues could have been as high as 400-700 
percent. These levels of tissue supersaturation are substantially 
higher than model predictions for marine mammals (Houser et al., 2001; 
Saunders et al., 2008). Both the degree of supersaturation and exposure 
levels observed to cause microbubble destabilization are unlikely to 
occur, either alone or in concert.
    Yet another hypothesis (decompression sickness) speculates that 
rapid ascent to the surface following exposure to a startling sound 
might produce tissue gas saturation sufficient for the evolution of 
nitrogen bubbles (Jepson et al., 2003; Fernandez et al., 2005; 
Fernandez et al., 2012). In this scenario, the rate of ascent would 
need to be sufficiently rapid to compromise behavioral or physiological 
protections against nitrogen bubble formation. Alternatively, Tyack et 
al. (2006) studied the deep diving behavior of beaked whales and 
concluded that: ``Using current models of breath-hold diving, we infer 
that their natural diving behavior is inconsistent with known problems 
of acute nitrogen supersaturation and embolism.'' Collectively, these 
hypotheses (rectified diffusion and decompression sickness) can be 
referred to as ``hypotheses of acoustically-mediated bubble growth.''
    Although theoretical predictions suggest the possibility for 
acoustically mediated bubble growth, there is considerable disagreement 
among scientists as to its likelihood (Piantadosi and Thalmann, 2004; 
Evans and Miller, 2003; Cox et al., 2006; Rommel et al., 2006). Crum 
and Mao (1996) hypothesized that received levels would have to exceed 
190 dB in order for there to be the possibility of significant bubble 
growth due to supersaturation of gases in the blood (i.e., rectified 
diffusion). Work conducted by Crum et al. (2005) demonstrated the 
possibility of rectified diffusion for short duration signals, but at 
exposure levels and tissue saturation levels that are highly improbable 
to occur in diving marine mammals. To date, energy levels predicted to 
cause in vivo bubble formations within diving cetaceans have not been 
evaluated (NOAA, 2002b). Although it has been argued that traumas from 
some beaked whale strandings are consistent with gas emboli and bubble-
induced tissue separations (Jepson et al., 2003), there is no 
conclusive evidence of this (Rommel et al., 2006). However, Jepson et 
al. (2003, 2005) and Fernandez et al. (2004, 2005, 2012) concluded that 
in vivo bubble formation, which may be exacerbated by deep, long-
duration, repetitive dives, may explain why beaked whales appear to be 
particularly vulnerable to MF/HF active sonar exposures. This has not 
been demonstrated for LF sonar exposures, such as SURTASS LFA sonar.
    In 2009, Hooker et al. tested two mathematical models to predict 
blood and tissue tension N2 (PN2) using field data from 
three beaked whale species: Northern bottlenose whales, Cuvier's beaked 
whales, and Blainville's beaked whales. The researchers aimed to 
determine if physiology (body mass, diving lung volume, and dive 
response) or dive behavior (dive depth and duration, changes in ascent 
rate, and diel behavior) would lead to differences in PN2 
levels and thereby decompression sickness risk between species.
    In their study, they compared results for previously published time 
depth recorder data (Hooker and Baird, 1999; Baird et al., 2006, 2008) 
from Cuvier's beaked whale, Blainville's beaked whale, and northern 
bottlenose whale. They reported that diving lung volume and extent of 
the dive response had a large effect on end-dive PN2. Also, 
results showed that dive profiles had a larger influence on end-dive 
PN2 than body mass differences between species. Despite diel 
changes (i.e., variation that occurs regularly every day or most days) 
in dive behavior, PN2 levels showed no consistent trend. 
Model output suggested that all three species live with tissue 
PN2 levels that would cause a significant proportion of 
decompression sickness cases in terrestrial mammals. The authors 
concluded that the dive behavior of Cuvier's beaked whale was different 
from both Blainville's beaked whale, and northern bottlenose whale, and 
resulted in higher predicted tissue

[[Page 19488]]

and blood N2 levels (Hooker et al., 2009) and suggested that the 
prevalence of Cuvier's beaked whales stranding after naval sonar 
exercises could be explained by either a higher abundance of this 
species in the affected areas or by possible species differences in 
behavior and/or physiology related to MF active sonar (Hooker et al., 
2009).
    Bernaldo de Quiros et al. (2012) showed that, among stranded 
whales, deep diving species of whales had higher abundances of gas 
bubbles compared to shallow diving species. Kvadsheim et al. (2012) 
estimated blood and tissue PN2 levels in species 
representing shallow, intermediate, deep diving cetaceans following 
behavioral responses to sonar and their comparisons found that deep 
diving species had higher end-dive blood and tissue N2 
levels, indicating a higher risk of developing gas bubble emboli 
compared with shallow diving species. Fahlmann et al. (2014) evaluated 
dive data recorded from sperm, killer, long-finned pilot, Blainville's 
beaked and Cuvier's beaked whales before and during exposure to low (1-
2 kHz) and mid (2-7 kHz) frequency active sonar (note that SURTASS LFA 
sonar is transmitted between 100-500 Hz, which is well below the low 
frequency sonar in these studies) in an attempt to determine if either 
differences in dive behavior or physiological responses to sonar are 
plausible risk factors for bubble formation. The authors suggested that 
CO2 may initiate bubble formation and growth, while elevated 
levels of N2 may be important for continued bubble growth. 
The authors also suggest that if CO2 plays an important role 
in bubble formation, a cetacean escaping a sound source may experience 
increased metabolic rate, CO2 production, and alteration in 
cardiac output, which could increase risk of gas bubble emboli. 
However, as discussed in Kvadsheim et al. (2012), the actual observed 
behavioral responses to sonar from the species in their study (sperm, 
killer, long-finned pilot, Blainville's beaked, and Cuvier's beaked 
whales) did not imply any significantly increased risk of decompression 
sickness due to high levels of N2. Therefore, further 
information is needed to understand the relationship between exposure 
to stimuli, behavioral response (discussed in more detail below), 
elevated N2 levels, and gas bubble emboli in marine mammals. 
The hypotheses for gas bubble formation related to beaked whale 
strandings is that beaked whales potentially have strong avoidance 
responses to MF active sonars because they sound similar to their main 
predator, the killer whale (Cox et al., 2006; Southall et al., 2007; 
Zimmer and Tyack, 2007; Baird et al., 2008; Hooker et al., 2009). 
Further investigation is needed to assess the potential validity of 
these hypotheses. However, because SURTASS LFA sonar transmissions are 
lower in frequency (less than 500 Hz) and dissimilar in characteristics 
from those of marine mammal predators the SURTASS LFA sonar 
transmissions are not expected to cause gas bubble formation or beaked 
whale strandings.
    To summarize, there are few data related to the potential for 
strong, anthropogenic underwater sounds to cause non-auditory physical 
effects in marine mammals. Such effects, if they occur at all, would 
presumably be limited situations where marine mammals were exposed to 
high powered sounds at close range over a prolonged period of time. The 
available data do not allow identification of a specific exposure level 
above which non-auditory effects can be expected (Southall et al., 
2007) or any meaningful quantitative predictions of the numbers (if 
any) of marine mammals that might be affected in those ways.
Acoustic Masking
    Marine mammals use acoustic signals for a variety of purposes, 
which differ among species, but include communication between 
individuals, navigation, foraging, reproduction, and learning about 
their environment (Erbe and Farmer, 2000; Tyack, 2000). Masking, or 
auditory interference, generally occurs when other sounds in the 
environment are of a similar frequency and are louder than auditory 
signals an animal is trying to receive. Masking is a phenomenon that 
affects animals trying to receive acoustic information about their 
environment, including sounds from other members of their species, 
predators, prey, and sounds that allow them to orient in their 
environment. Masking these acoustic signals can disrupt the behavior of 
individual animals, groups of animals, or entire populations.
    The extent of the masking interference depends on the spectral, 
temporal, and spatial relationships between the signals an animal is 
trying to receive and the masking noise, in addition to other factors. 
In humans, significant masking of tonal signals occurs as a result of 
exposure to noise in a narrow band of similar frequencies. As the sound 
level increases, the detection of frequencies above those of the 
masking stimulus decreases. This principle is expected to apply to 
marine mammals as well because of common biomechanical cochlear 
properties across taxa.
    Richardson et al. (1995b) argued that the maximum radius of 
influence of an industrial noise (including broadband low-frequency 
sound transmission) on a marine mammal is the distance from the source 
to the point at which the noise can barely be heard. This range is 
determined by either the hearing sensitivity of the animal or the 
background noise level present. Industrial masking is most likely to 
affect some species' ability to detect communication calls and natural 
sounds (i.e., surf noise, prey noise, etc.) (Richardson et al., 1995).
    The echolocation calls of toothed whales are subject to masking by 
high-frequency sound. Human data indicate that low-frequency sounds can 
mask high-frequency sounds (i.e., upward masking). Studies on captive 
odontocetes by Au et al. (1974, 1985, 1993) indicate that some species 
may use various processes to reduce masking effects (e.g., adjustments 
in echolocation call intensity or frequency as a function of background 
noise conditions). There is also evidence that the directional hearing 
abilities of odontocetes are useful in reducing masking at the higher 
frequencies these cetaceans use to echolocate, but not at the low-to-
moderate frequencies they use to communicate (Zaitseva et al., 1980). A 
study by Nachtigall and Supin (2008) showed that false killer whales 
adjust their hearing to compensate for ambient sounds and the intensity 
of returning echolocation signals. Holt et al. (2009) measured killer 
whale call source levels and background noise levels in the one to 40 
kHz band and reported that the whales increased their call source 
levels by one dB SPL for every one dB SPL increase in background noise 
level. Similarly, another study on St. Lawrence River belugas reported 
a similar rate of increase in vocalization activity in response to 
passing vessels (Scheifele et al., 2005).
    Parks et al. (2007) provided evidence of behavioral changes in the 
acoustic behaviors of the endangered North Atlantic right whale, and 
the South Atlantic right whale, and suggested that these were 
correlated to increased underwater noise levels. The study indicated 
that right whales might shift the frequency band of their calls to 
compensate for increased in-band background noise. The significance of 
their result is the indication of potential species-wide behavioral 
change in response to gradual, chronic increases in underwater ambient 
noise. Di Iorio and Clark (2010) showed that blue whale calling rates 
vary in association with seismic sparker survey activity, with whales 
calling more on days with

[[Page 19489]]

survey than on days without surveys. They suggested that the whales 
called more during seismic survey periods as a way to compensate for 
the elevated noise conditions.
    Risch et al. (2012) documented reductions in humpback whale 
vocalizations in the Stellwagen Bank National Marine Sanctuary 
concurrent with transmissions of the Ocean Acoustic Waveguide Remote 
Sensing (OAWRS) low-frequency fish sensor system at distances of 200 km 
(124 mi) from the source. The recorded OAWRS produced a series of 
frequency modulated pulses and the signal received levels ranged from 
88 to 110 dB re: 1 [mu]Pa (Risch, et al., 2012). The authors 
hypothesized that individuals did not leave the area but instead ceased 
singing and noted that the duration and frequency range of the OAWRS 
signals (a novel sound to the whales) were similar to those of natural 
humpback whale song components used during mating (Risch et al., 2012). 
Thus, the novelty of the sound to humpback whales in the study area 
provided a compelling contextual probability for the observed effects 
(Risch et al., 2012). However, the authors did not state or imply that 
these changes had long-term effects on individual animals or 
populations (Risch et al., 2012).
    Redundancy and context can also facilitate detection of weak 
signals. These phenomena may help marine mammals detect weak sounds in 
the presence of natural or manmade noise. Most masking studies in 
marine mammals present the test signal and the masking noise from the 
same direction. The sound localization abilities of marine mammals 
suggest that, if signal and noise come from different directions, 
masking would not be as severe as some masking studies might suggest 
(Richardson et al., 1995). The dominant background noise may be highly 
directional if it comes from a particular anthropogenic source such as 
a ship or industrial site. Directional hearing may significantly reduce 
the masking effects of these sounds by improving the effective signal-
to-noise ratio.
    As mentioned previously, the hearing ranges of mysticetes overlap 
with the frequencies of the SURTASS LFA sonar sources. The closer the 
characteristics of the masking signal to the signal of interest, the 
more likely masking is to occur. The Navy provided an analysis of 
marine mammal hearing and masking in Subchapter 4.2.2.1.4 of the DSEIS/
SOEIS, and the masking effects of the SURTASS LFA sonar signal are 
expected to be limited for a number of reasons. First, the frequency 
range (bandwidth) of the system is limited to approximately 30 Hz, and 
the instantaneous bandwidth at any given time of the signal is small, 
on the order of 10 Hz. Second, the average duty cycle is always less 
than 20 percent and, based on past SURTASS LFA sonar operational 
parameters (2003 to 2016), is normally 7.5 to 10 percent. Third, given 
the average maximum pulse length (60 sec), and the fact that the 
signals vary and do not remain at a single frequency for more than 10 
sec, SURTASS LFA sonar is not likely to cause significant masking. In 
other words, the LFA sonar transmissions are coherent, narrow bandwidth 
signals of six to 100 sec in length followed by a quiet period of six 
to 15 minutes. Therefore, the effect of masking will be limited because 
animals that use this frequency range typically use broader bandwidth 
signals. As a result, the chances of an LFA sonar sound actually 
overlapping whale calls at levels that would interfere with their 
detection and recognition will be extremely low.
Impaired Communication
    In addition to making it more difficult for animals to perceive 
acoustic cues in their environment, anthropogenic sound presents 
separate challenges for animals that are vocalizing. When they 
vocalize, animals are aware of environmental conditions that affect the 
``active space'' of their vocalizations, which is the maximum area 
within which their vocalizations can be detected before they drop to 
the level of ambient noise (Brenowitz, 2004; Brumm et al., 2004; Lohr 
et al., 2003). Animals are also aware of environmental conditions that 
affect whether listeners can discriminate and recognize their 
vocalizations apart from other sounds, which is more important than 
simply detecting that a vocalization is occurring (Brenowitz, 1982; 
Brumm et al., 2004; Dooling, 2004, Marten and Marler, 1977; Patricelli 
et al., 2006). Most species that vocalize are able to adapt by 
adjusting their vocalizations to increase the signal-to-noise ratio, 
active space, and recognizability/distinguishability of their 
vocalizations in the face of temporary changes in background noise 
(Brumm et al., 2004; Patricelli et al., 2006). Vocalizing animals can 
make adjustments to vocalization characteristics such as the frequency 
structure, amplitude, temporal structure and temporal delivery.
    Many animals will combine several of these strategies to compensate 
for high levels of background noise. Anthropogenic sounds which reduce 
the signal-to-noise ratio of animal vocalizations, increase the masked 
auditory thresholds of animals listening for such vocalizations, or 
reduce the active space of an animal's vocalizations impair 
communications between animals. Most animals that vocalize have evolved 
strategies to compensate for the effects of short-term or temporary 
increases in background or ambient noise on their songs or calls. 
Although the fitness consequences of these vocal adjustments are not 
directly known in all instances, like most other trade-offs animals 
must make, some of these strategies probably come at a cost (Patricelli 
et al., 2006). Shifting songs and calls to higher frequencies may also 
impose energetic costs (Lambrechts, 1996). For example in birds, 
vocalizing more loudly in noisy environments may have energetic costs 
that decrease the net benefits of vocal adjustment and alter a bird's 
energy budget (Brumm, 2004; Wood and Yezerinac, 2006).
Stress Responses
    Classic stress responses begin when an animal's central nervous 
system perceives a potential threat to its homeostasis. That perception 
triggers stress responses regardless of whether a stimulus actually 
threatens the animal; the mere perception of a threat is sometimes 
sufficient to trigger a stress response (Moberg, 2000; Sapolsky et al., 
2005; Seyle, 1950). Once an animal's central nervous system perceives a 
threat, it mounts a biological response or defense that consists of a 
combination of the four general biological defense responses: 
Behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses.
    According to Moberg (2000), in the case of many stressors, an 
animal's first and most economical (in terms of biotic costs) response 
is behavioral avoidance of the potential stressor or avoidance of 
continued exposure to a stressor. An animal's second line of defense to 
stressors involves the sympathetic part of the autonomic nervous system 
and the classical ``fight or flight'' response which includes the 
cardiovascular system, the gastrointestinal system, the exocrine 
glands, and the adrenal medulla to produce changes in heart rate, blood 
pressure, and gastrointestinal activity that humans commonly associate 
with ``stress.'' These responses have a relatively short duration and 
may or may not have significant long-term effect on an animal's 
welfare.
    An animal's third line of defense to stressors involves its 
neuroendocrine or sympathetic nervous systems; the system that has 
received the most study has been the hypothalmus-pituitary-adrenal 
system (also known as the HPA

[[Page 19490]]

axis in mammals or the hypothalamus-pituitary-interrenal axis in fish 
and some reptiles). Unlike stress responses associated with the 
autonomic nervous system, virtually all neuro-endocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction (Moberg, 1987; Rivier and Rivest, 
1991), altered metabolism (Elasser et al., 2000), reduced immune 
competence (Blecha, 2000), and behavioral disturbance (Moberg, 1987; 
Blecha, 2000). Increases in the circulation of glucocorticosteroids 
(cortisol, corticosterone, and aldosterone in marine mammals; see 
Romano et al., 2004) have been equated with stress for many years.
    The primary distinction between stress, which is adaptive and does 
not normally place an animal at risk, and distress is the biotic cost 
of the response. During a stress response, an animal uses glycogen 
stores that can be quickly replenished once the stress is alleviated. 
In such circumstances, the cost of the stress response would not pose a 
risk to the animal's welfare. However, when an animal does not have 
sufficient energy reserves to satisfy the energetic costs of a stress 
response, energy resources must be diverted from other biotic 
functions, which impair those functions. For example, when a stress 
response diverts energy away from growth in young animals, those 
animals may experience stunted growth. When a stress response diverts 
energy from a fetus, an animal's reproductive success and fitness will 
suffer. In these cases, the animals will have entered a pre-
pathological or pathological state which is called distress (sensu 
Seyle, 1950) or allostatic loading (sensu McEwen and Wingfield, 2003). 
This pathological state will last until the animal replenishes its 
biotic reserves sufficient to restore normal function. Note that these 
examples involve a long-term (days or weeks) stress response exposure 
to stimuli.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses have also been documented 
fairly well through controlled experiments; because this physiology 
exists in every vertebrate that has been studied, it is not surprising 
that stress responses and their costs have been documented in both 
laboratory and free-living animals (for examples see, Holberton et al., 
1996; Hood et al., 1998; Jessop et al., 2003; Krausman et al., 2004; 
Lankford et al., 2005; Thompson and Hamer, 2000).
    There is limited information on the physiological responses of 
marine mammals to anthropogenic sound exposure, as most observations 
have been limited to short-term behavioral responses, which included 
cessation of feeding, resting, or social interactions. Information has 
been collected on the physiological responses of marine mammals to 
anthropogenic sounds (Fair and Becker, 2000; Romano et al., 2002; 
Wright et al., 2008), and various efforts have been undertaken to 
investigate the impact from vessels including whale watching vessels as 
well as general vessel traffic noise (Bain, 2002; Erbe, 2002; Noren et 
al., 2009; Williams et al., 2006, 2009, 2014a, 2014b; Read et al., 
2014; Rolland et al., 2012; Pirotta et al., 2015). This body of 
research for the most part has investigated impacts associated with the 
presence of chronic stressors, which differ significantly from the 
proposed Navy SURTASS LFA sonar activities. For example, in the 
analysis of energy costs to killer whales, Williams et al. (2009) 
suggested that whale-watching in Canada's Johnstone Strait resulted in 
lost feeding opportunities due to vessel disturbance, which could carry 
higher costs than other measures of behavioral change might suggest. 
Ayres et al. (2012) reported on research in the Salish Sea (state of 
Washington) involving the measurement of southern resident killer whale 
fecal hormones to assess two potential threats to the species recovery: 
Lack of prey (salmon) and impacts to behavior from vessel traffic. The 
authors suggested that the lack of prey overshadowed any population-
level physiological impacts on southern resident killer whales from 
vessel traffic. Rolland et al. (2012) found that noise reduction from 
reduced ship traffic in the Bay of Fundy was associated with decreased 
stress in North Atlantic right whales. In a conceptual model developed 
by the Population Consequences of Acoustic Disturbance (PCAD) working 
group, serum hormones were identified as possible indicators of 
behavioral effects that are translated into altered rates of 
reproduction and mortality (NRC, 2005). The Office of Naval Research 
hosted a workshop (Effects of Stress on Marine Mammals Exposed to 
Sound) in 2009 that focused on this very topic (ONR, 2009). Ultimately, 
the PCAD working group issued a report (Cochrem, 2014) that summarized 
information compiled from 239 papers or book chapters relating to 
stress in marine mammals and concluded that stress responses can last 
from minutes to hours and, while we typically focus on adverse stress 
responses, stress response is part of a natural process to help animals 
adjust to changes in their environment and can also be either neutral 
or beneficial.
    Despite the lack of robust information on stress responses for 
marine mammals exposed to anthropogenic sounds, studies of other marine 
and terrestrial animals lead us to expect some marine mammals to 
experience physiological stress responses and, perhaps, physiological 
responses that would be classified as distress upon exposure to low-
frequency sounds. For example, Jansen (1998) reported on the 
relationship between acoustic exposures and physiological responses 
that are indicative of stress responses in humans (e.g., elevated 
respiration and increased heart rates). Jones (1998) reported on 
reductions in human performance when faced with acute, repetitive 
exposures to acoustic disturbance. Trimper et al. (1998) reported on 
the physiological stress responses of osprey to low-level aircraft 
noise while Krausman et al. (2004) reported on the auditory and 
physiology stress responses of endangered Sonoran pronghorn to military 
overflights. Smith et al. (2004a, 2004b) identified noise-induced 
physiological transient stress responses in hearing-specialist fish 
(i.e., goldfish) that accompanied short- and long-term hearing losses. 
Welch and Welch (1970) reported physiological and behavioral stress 
responses that accompanied damage to the inner ears of fish and several 
mammals.
    Hearing is one of the primary senses marine mammals use to gather 
information about their environment and communicate with conspecifics. 
Although empirical information on the relationship between sensory 
impairment (TTS, PTS, and acoustic masking) and stress in marine 
mammals remains limited, it is reasonable to assume that reducing an 
animal's ability to gather information about its environment and 
communicate with conspecifics could induce stress in animals that use 
hearing as their primary sensory mechanism. We also assume that 
acoustic exposures sufficient to trigger onset of PTS or TTS would be 
accompanied by physiological stress responses, because terrestrial 
animals exhibit those responses under similar conditions (NRC, 2003). 
More importantly, due to the effect of noise and the need to 
effectively gather acoustic information and respond, marine mammals 
might experience stress responses at received levels lower than those 
necessary to trigger onset of TTS. Based on empirical studies of the

[[Page 19491]]

time required to recover from stress responses (Moberg, 2000), NMFS 
also assumes that stress responses could persist beyond the time 
interval required for animals to recover from TTS and might result in 
pathological and pre-pathological states that would be as significant 
as behavioral responses associated with TTS.
Behavioral Response/Disturbance
    Behavioral responses to sound are highly variable and context-
specific. Many different variables can influence an animal's perception 
of, as well as the nature and magnitude of response to, an acoustic 
event. An animal's prior experience with a sound or sound source 
affects whether it is less likely (habituation) or more likely 
(sensitization) to respond to certain sounds in the future. Animals can 
also be innately pre-disposed to respond to certain sounds in certain 
ways (Southall et al., 2007). Related to the sound itself, the 
perceived nearness of the sound, bearing of the sound (approaching vs. 
retreating), similarity of the sound to biologically relevant sounds in 
the animal's environment (i.e., calls of predators, prey, or 
conspecifics), and familiarity of the sound may affect the way an 
animal responds to the sound (Southall et al., 2007; DeRuiter et al., 
2013). Individuals of different age, gender, reproductive status, etc. 
among most populations will have variable hearing capabilities, and 
differing behavioral sensitivities to sounds that will be affected by 
prior conditioning, experience, and current activities of those 
individuals. Often, specific acoustic features of the sound and 
contextual variables (i.e., proximity, duration, or recurrence of the 
sound or the current behavior that the marine mammal is engaged in or 
its prior experience), as well as entirely separate factors such as the 
physical presence of a nearby vessel, may be more relevant to the 
animal's response than the received level alone. For example, Goldbogen 
et al. (2013) demonstrated that individual behavioral state was 
critically important in determining response of blue whales to sonar, 
noting that individuals engaged in deep (>50 m) feeding behavior had 
greater dive responses than those in shallow feeding or non-feeding 
conditions. Some blue whales in the Goldbogen et al. (2013) study that 
were engaged in shallow feeding behavior demonstrated no clear changes 
in diving or movement even when RLs were high (~160 dB re 1[micro]Pa) 
for exposures to 3-4 kHz sonar signals, while others showed a clear 
response at exposures at lower RLs of sonar and pseudorandom noise.
    Studies by DeRuiter et al. (2012) indicate that variability of 
responses to acoustic stimuli depends not only on the species receiving 
the sound and the sound source, but also on the social, behavioral, or 
environmental contexts of exposure. Another study by DeRuiter et al. 
(2013) examined behavioral responses of Cuvier's beaked whales to MF 
sonar and found that whales responded strongly at low received levels 
(RL of 89-127 dB re 1[micro]Pa) by ceasing normal fluking and 
echolocation, swimming rapidly away, and extending both dive duration 
and subsequent non-foraging intervals when the sound source was 3.4-9.5 
km away. Importantly, this study also showed that whales exposed to a 
similar range of RLs (78-106 dB re 1[micro]Pa) from distant sonar 
exercises (118 km away) did not elicit such responses, suggesting that 
context may moderate reactions.
    Ellison et al. (2012) outlined an approach to assessing the effects 
of sound on marine mammals that incorporates contextual-based factors. 
The authors recommend considering not just the received level of sound, 
but also the activity the animal is engaged in at the time the sound is 
received, the nature and novelty of the sound (i.e., is this a new 
sound from the animal's perspective), and the distance between the 
sound source and the animal. They submit that this ``exposure 
context,'' as it is termed, greatly influences the type of behavioral 
response exhibited by the animal. This sort of contextual information 
is challenging to predict with accuracy for ongoing activities that 
occur over large spatial and temporal expanses. While contextual 
elements of this sort are typically not included in calculations to 
quantify take estimates of marine mammals, they are often considered 
qualitatively in the analysis of the likely consequences of sound 
exposure, where supporting information is available.
    Friedlaender et al. (2016) provided the first integration of direct 
measures of prey distribution and density variables incorporated into 
across-individual analyses of behavior responses of blue whales to 
sonar, and demonstrated a 5-fold increase in the ability to quantify 
variability in blue whale diving behavior. These results illustrate 
that responses evaluated without such measurements for foraging animals 
may be misleading, which again illustrates the context-dependent nature 
of the probability of response.
    Exposure of marine mammals to sound sources can result in, but is 
not limited to, no response or any of the following observable 
responses: Increased alertness; orientation or attraction to a sound 
source; vocal modifications; cessation of feeding; cessation of social 
interaction; alteration of movement or diving behavior; avoidance; 
habitat abandonment (temporary or permanent); and, in severe cases, 
panic, flight, stampede, or stranding, potentially resulting in death 
(Southall et al., 2007). A review of marine mammal responses to 
anthropogenic sound was first conducted by Richardson (1995). More 
recent reviews (Nowacek et al., 2007; DeRuiter et al., 2012 and 2013; 
Ellison et al., 2012) addressed studies conducted since 1995 and 
focused on observations where the received sound level of the exposed 
marine mammal(s) was known or could be estimated. In a review of 
experimental field studies to measure behavioral responses of cetaceans 
to sonar, Southall et al. (2016) states that results demonstrate that 
some individuals of different species display clear yet varied 
responses, some of which have negative implications, while others 
appear to tolerate high levels, and that responses may not be fully 
predicable with simple acoustic exposure metrics (e.g., received sound 
level). Rather, the authors state that differences among species and 
individuals along with contextual aspects of exposure (e.g., behavioral 
state) appear to affect response probability. The following subsections 
provide examples of behavioral responses that provide an idea of the 
variability in behavioral responses that would be expected given the 
different sensitivities of marine mammal species to sound and the wide 
range of potential acoustic sources to which a marine mammal may be 
exposed. Predictions about the types of behavioral responses that could 
occur for a given sound exposure should be determined from the 
literature that is available for each species or extrapolated from 
closely related species when no information exists, along with 
contextual factors.
    Alteration of Diving or Movement. Changes in dive behavior can vary 
widely. They may consist of increased or decreased dive times and 
surface intervals as well as changes in the rates of ascent and descent 
during a dive. Variations in dive behavior may reflect interruptions in 
biologically significant activities (e.g., foraging) or they may be of 
little biological significance. Variations in dive behavior may also 
expose an animal to potentially harmful conditions (e.g., increasing 
the chance of ship-strike) or may serve as an avoidance response that 
enhances survivorship. The impact of a variation in diving resulting 
from an acoustic

[[Page 19492]]

exposure depends on what the animal is doing at the time of the 
exposure and the type and magnitude of the response.
    Nowacek et al. (2004) reported disruptions of dive behaviors in 
foraging North Atlantic right whales when exposed to an alerting 
stimulus, which they noted could lead to an increased likelihood of 
ship strike. However, the whales did not respond to playbacks of either 
right whale social sounds or vessel noise, highlighting the importance 
of the sound characteristics in producing a behavioral reaction. 
Conversely, Indo-Pacific humpback dolphins have been observed to dive 
for longer periods of time in areas where vessels were present and/or 
approaching (Ng and Leung, 2003). In both of these studies, the 
influence of the sound exposure cannot be decoupled from the physical 
presence of a surface vessel, thus complicating interpretations of the 
relative contribution of each stimulus to the response. Indeed, the 
presence of surface vessels, their approach, and the speed of approach, 
all seemed to be significant factors in the response of the Indo-
Pacific humpback dolphins (Ng and Leung, 2003). Low-frequency signals 
of the Acoustic Thermometry of Ocean Climate (ATOC) sound source were 
not found to affect dive times of humpback whales in Hawaiian waters 
(Frankel and Clark, 2000) or to overtly affect elephant seal dives 
(Costa et al., 2003). They did, however, produce subtle effects that 
varied in direction and degree among the individual seals, illustrating 
the varied nature of behavioral effects and consequent difficulty in 
defining and predicting them. Lastly, as noted previously, DeRuiter et 
al. (2013) noted that distance from a sound source may moderate marine 
mammal reactions in their study of Cuvier's beaked whales showing the 
whales swimming rapidly and silently away when a sonar signal was 3.4-
9.5 km away while showing no such reaction to the same signal when the 
signal was 118 km away even though the RLs were similar.
    Foraging. Disruption of feeding behavior can be difficult to 
correlate with anthropogenic sound exposure, so it is usually inferred 
by observed displacement from known foraging areas, the appearance of 
secondary indicators (e.g., bubble nets or sediment plumes), or changes 
in dive behavior. Noise from seismic surveys was not found to impact 
the feeding behavior of western gray whales off the coast of Russia 
(Yazvenko et al., 2007) and sperm whales engaged in foraging dives did 
not abandon dives when exposed to distant signatures of seismic airguns 
(Madsen et al., 2006). Balaenopterid whales exposed to moderate SURTASS 
LFA sonar demonstrated no responses or change in foraging behavior that 
could be attributed to the low-frequency sounds (Croll et al., 2001), 
whereas five out of six North Atlantic right whales exposed to an 
acoustic alarm interrupted their foraging dives (Nowacek et al., 2004). 
Although the received sound pressure level was similar in the latter 
two studies, the frequency, duration, and temporal pattern of signal 
presentation were different. These factors, as well as differences in 
species sensitivity, are likely contributing factors to the 
differential response.
    Blue whales exposed to simulated mid-frequency sonar in the 
Southern California Bight were less likely to produce low frequency 
calls usually associated with feeding behavior (Melc[oacute]n et al., 
2012). However, the authors were unable to determine if suppression of 
low frequency calls reflected a change in their feeding performance, or 
abandonment of foraging behavior and indicated that implications of the 
documented responses are unknown. Further, it is not known whether the 
lower rates of calling actually indicated a reduction in feeding 
behavior or social contact since the study used data from remotely 
deployed, passive acoustic monitoring buoys. In contrast, blue whales 
increased their likelihood of calling when ship noise was present, and 
decreased their likelihood of calling in the presence of explosive 
noise, although this result was not statistically significant 
(Melc[oacute]n et al., 2012). Additionally, the likelihood of an animal 
calling decreased with the increased received level of mid-frequency 
sonar, beginning at a SPL of approximately 110-120 dB re 1 [micro]Pa 
(Melc[oacute]n et al., 2012). Results from the 2010-2011 field season 
of an ongoing behavioral response study in Southern California waters 
indicated that, in some cases and at low received levels, tagged blue 
whales responded to mid-frequency sonar but that those responses were 
mild and there was a quick return to their baseline activity (Southall 
et al., 2011; Southall et al., 2012). Goldbogen et al., (2013) 
monitored behavioral responses of tagged blue whales located in feeding 
areas when exposed to simulated MFA sonar. Responses varied depending 
on behavioral context, with deep feeding whales being more 
significantly affected (i.e., generalized avoidance; cessation of 
feeding; increased swimming speeds; or directed travel away from the 
source) compared to surface feeding individuals that typically showed 
no change in behavior. Non-feeding whales also seemed to be affected by 
exposure. The authors indicate that disruption of feeding and 
displacement could impact individual fitness and health. However, for 
this to be true, we would have to assume that an individual whale could 
not compensate for this lost feeding opportunity by either immediately 
feeding at another location, by feeding shortly after cessation of 
acoustic exposure, or by feeding at a later time. There is no 
indication this is the case for the proposed SURTASS LFA sonar 
activities, particularly since unconsumed prey would likely still be 
available in the environment in most cases following the cessation of 
acoustic exposure. A determination of whether foraging disruptions 
incur fitness consequences will require information on or estimates of 
the energetic requirements of the individuals and the relationship 
between prey availability, foraging effort and success, and the life 
history stage of the animal.
    Social Relationships. Social interactions between mammals can be 
affected by noise via the disruption of communication signals or by the 
displacement of individuals. Sperm whales responded to military sonar, 
apparently from a submarine, by dispersing from social aggregations, 
moving away from the sound source, remaining relatively silent, and 
becoming difficult to approach (Watkins et al., 1985). In contrast, 
sperm whales in the Mediterranean that were exposed to submarine sonar 
continued calling (J. Gordon pers. comm. cited in Richardson et al., 
1995). However, social disruptions must be considered in context of the 
relationships that are affected. While some disruptions may not have 
deleterious effects, others, such as long-term or repeated disruptions 
of mother/calf pairs or interruption of mating behaviors, have the 
potential to affect the growth and survival or reproductive effort/
success of individuals.
    Vocalizations. (also see Masking Section)--Vocal changes in 
response to anthropogenic noise can occur across the repertoire of 
sound production modes used by marine mammals, such as whistling, 
echolocation click production, calling, and singing. Changes may result 
in response to a need to compete with an increase in background noise 
or may reflect an increased vigilance or startle response. For example, 
in the presence of low-frequency active sonar, humpback whales have 
been observed to increase the length of their ''songs'' (Miller et al.,

[[Page 19493]]

2000; Fristrup et al., 2003), possibly due to the overlap in 
frequencies between the whale song and the low-frequency active sonar. 
A similar compensatory effect for the presence of low-frequency vessel 
noise has been suggested for right whales; right whales have been 
observed to shift the frequency content of their calls upward while 
reducing the rate of calling in areas of increased anthropogenic noise 
(Parks et al., 2007). Killer whales off the northwestern coast of the 
United States have been observed to increase the duration of primary 
calls once a threshold in observing vessel density (e.g., whale 
watching) was reached, which has been suggested as a response to 
increased masking noise produced by the vessels (Foote et al., 2004). 
In contrast, both sperm and pilot whales potentially ceased sound 
production during the Heard Island feasibility test (Bowles et al., 
1994), although it cannot be absolutely determined whether the 
inability to acoustically detect the animals was due to the cessation 
of sound production or the displacement of animals from the area.
    Avoidance. Avoidance is the displacement of an individual from an 
area as a result of the presence of a sound. Richardson et al. (1995) 
noted that avoidance reactions are the most obvious manifestations of 
disturbance in marine mammals. Avoidance is qualitatively different 
from the flight response, but also differs in the magnitude of the 
response (i.e., directed movement, rate of travel, etc.). Oftentimes, 
avoidance is temporary and animals return to the area once the noise 
has ceased. However, longer term displacement is possible and can lead 
to changes in abundance or distribution patterns of the species in the 
affected region if animals do not become acclimated to the presence of 
the chronic sound (Blackwell et al., 2004; Bejder et al., 2006; 
Teilmann et al., 2006). Acute avoidance responses have been observed in 
captive porpoises and pinnipeds exposed to a number of different sound 
sources (Kastelein et al., 2001; Finneran et al., 2003; Kastelein et 
al., 2006a; Kastelein et al., 2006b). Short-term avoidance of seismic 
surveys, low-frequency emissions, and acoustic deterrents have also 
been noted in wild populations of odontocetes (Bowles et al., 1994; 
Goold, 1996; 1998; Stone et al., 2000; Morton and Symonds, 2002) and to 
some extent in mysticetes (Gailey et al., 2007), while long-term or 
repetitive/chronic displacement for some dolphin groups and for 
manatees has been suggested to result from the presence of chronic 
vessel noise (Haviland-Howell et al., 2007; Miksis-Olds et al., 2007).
    In 1998, the Navy conducted a Low Frequency Sonar Scientific 
Research Program (LFS SRP) specifically to study behavioral responses 
of several species of marine mammals to exposure to LF sound, including 
one phase that focused on the behavior of gray whales to low frequency 
sound signals. The objective of this phase of the LFS SRP was to 
determine whether migrating gray whales respond more strongly to 
received levels (RL), sound gradient, or distance from the source, and 
to compare whale avoidance responses to an LF source in the center of 
the migration corridor versus in the offshore portion of the migration 
corridor. A single source was used to broadcast LFA sonar sounds at RLs 
of 170-178 dB re 1[micro]Pa. The Navy reported that the whales showed 
some avoidance responses when the source was moored one mile (1.8 km) 
offshore, and located within in the migration path, but the whales 
returned to their migration path when they were a few kilometers beyond 
the source. When the source was moored two miles (3.7 km) offshore, 
responses were much less even when the source level was increased to 
achieve the same RLs in the middle of the migration corridor as whales 
received when the source was located within the migration corridor 
(Clark et al., 1999). In addition, the researchers noted that the 
offshore whales did not seem to avoid the louder offshore source.
    Also during the LFS SRP, researchers sighted numerous odontocete 
and pinniped species in the vicinity of the sound exposure tests with 
LFA sonar. The MF and HF hearing specialists present in the study area 
showed no immediately obvious responses or changes in sighting rates as 
a function of source conditions. Consequently, the researchers 
concluded that none of these species had any obvious behavioral 
reaction to LFA sonar signals at received levels similar to those that 
produced only minor short-term behavioral responses in the baleen 
whales (i.e., LF hearing specialists). Thus, for odontocetes, the 
chances of injury and/or significant behavioral responses to SURTASS 
LFA sonar would be low given the MF/HF specialists' observed lack of 
response to LFA sounds during the LFS SRP and due to the MF/HF 
frequencies to which these animals are adapted to hear (Clark and 
Southall, 2009).
    Maybaum (1993) conducted sound playback experiments to assess the 
effects of mid-frequency active sonar on humpback whales in Hawaiian 
waters. Specifically, she exposed focal pods to sounds of a 3.3-kHz 
sonar pulse, a sonar frequency sweep from 3.1 to 3.6 kHz, and a control 
(blank) tape while monitoring the behavior, movement, and underwater 
vocalizations. The two types of sonar signals differed in their effects 
on the humpback whales, but both resulted in avoidance behavior. The 
whales responded to the pulse by increasing their distance from the 
sound source and responded to the frequency sweep by increasing their 
swimming speeds and track linearity. In the Caribbean, sperm whales 
avoided exposure to mid-frequency submarine sonar pulses, in the range 
of 1000 Hz to 10,000 Hz (IWC 2005).
    Kvadsheim et al., (2007) conducted a controlled exposure experiment 
in which killer whales fitted with D-tags were exposed to mid-frequency 
active sonar (Source A: a 1.0 s upsweep 209 dB @1-2 kHz every 10 sec 
for 10 minutes; Source B: with a 1.0 s upsweep 197 dB @6-7 kHz every 10 
sec for 10 min). When exposed to Source A, a tagged whale and the group 
it was traveling with did not appear to avoid the source. When exposed 
to Source B, the tagged whales, along with other whales that had been 
carousel feeding where killer whales cooperatively herd fish schools 
into a tight ball towards the surface and feed on the fish which have 
been stunned by tailslaps and subsurface feeding (Simila, 1997), ceased 
feeding during the approach of the sonar and moved rapidly away from 
the source. When exposed to Source B, Kvadsheim and his co-workers 
reported that a tagged killer whale seemed to try to avoid further 
exposure to the sound field by the following behaviors: Immediately 
swimming away (horizontally) from the source of the sound; engaging in 
a series of erratic and frequently deep dives that seemed to take it 
below the sound field; or swimming away while engaged in a series of 
erratic and frequently deep dives. Although the sample sizes in this 
study are too small to support statistical analysis, the behavioral 
responses of the orcas were consistent with the results of other 
studies.
    In 2007, the first in a series of behavioral response studies (BRS) 
on deep diving odontocetes conducted by NMFS, Navy, and other 
scientists showed one beaked whale (Mesoplodon densirostris) responding 
to an MF active sonar playback. Tyack et al. (2011) indicates that the 
playback began when the tagged beaked whale was vocalizing at depth (at 
the deepest part of a typical feeding dive), following a previous 
control with no sound exposure. The whale appeared to stop clicking 
significantly earlier than usual, when

[[Page 19494]]

exposed to mid-frequency signals in the 130-140 dB (rms) received level 
range. After a few more minutes of the playback, when the received 
level reached a maximum of 140-150 dB, the whale ascended on the slow 
side of normal ascent rates with a longer than normal ascent, at which 
point the exposure was terminated. The results are from a single 
experiment and a greater sample size is needed before robust and 
definitive conclusions can be drawn.
    Tyack et al. (2011) also indicate that Blainville's beaked whales 
(a resident species within the Tongue of the Ocean, Bahamas study area) 
appear to be sensitive to noise at levels well below the onset of 
expected TTS (approximately 160 dB re: 1[mu]Pa at 1 m). This 
sensitivity was manifested by an adaptive movement away from a sound 
source. This response was observed irrespective of whether the signal 
transmitted was within the band width of MF active sonar, which 
suggests that beaked whales may not respond to the specific sound 
signatures. Instead, they may be sensitive to any pulsed sound from a 
point source in the frequency range of the MF active sonar 
transmission. The response to such stimuli appears to involve the 
beaked whale increasing the distance between it and the sound source.
    Southall et al. (2016) indicates that results from Tyack et al. 
(2011); Miller et al. (2015), Stimpert et al. (2014), and DeRuiter et 
al. (2013) all demonstrate clear, strong, and pronounced but varied 
behavioral changes including sustained avoidance with associated 
energetic swimming and cessation of feeding behavior at quite low 
received levels (~100 to 135 dB re 1Pa) for exposures to simulated or 
active MF military sonars (1 to 8 kHz) with sound sources approximately 
2 to 5 km away.
    In the 2010 BRS study, researchers again used controlled exposure 
experiments (CEE) to carefully measure behavioral responses of 
individual animals to sound exposures of MF active sonar and pseudo-
random noise. For each sound type, some exposures were conducted when 
animals were in a surface feeding (approximately 164 ft (50 m) or less) 
and/or socializing behavioral state and others while animals were in a 
deep feeding (greater than 164 ft (50 m)) and/or traveling mode. The 
researchers conducted the largest number of CEEs on blue whales (n=19) 
and of these, 11 CEEs involved exposure to the MF active sonar sound 
type. For the majority of CEE transmissions of either sound type, they 
noted few obvious behavioral responses detected either by the visual 
observers or on initial inspection of the tag data. The researchers 
observed that throughout the CEE transmissions, up to the highest 
received sound level (absolute RMS value approximately 160 dB re: 
1[mu]Pa with signal-to-noise ratio values over 60 dB), two blue whales 
continued surface feeding behavior and remained at a range of around 
3,820 ft (1,000 m) from the sound source (Southall et al., 2011). In 
contrast, another blue whale (later in the day and greater than 11.5 mi 
(18.5 km; 10 nmi) from the first CEE location) exposed to the same 
stimulus (MFA) while engaged in a deep feeding/travel state exhibited a 
different response. In that case, the blue whale responded almost 
immediately following the start of sound transmissions when received 
sounds were just above ambient background levels (Southall et al., 
2011). The authors note that this kind of temporary avoidance behavior 
was not evident in any of the nine CEEs involving blue whales engaged 
in surface feeding or social behaviors, but was observed in three of 
the ten CEEs for blue whales in deep feeding/travel behavioral modes 
(one involving MFA sonar; two involving pseudo-random noise) (Southall 
et al., 2011). The results of this study, as well as the results of the 
DeRuiter et al. (2013) study of Cuvier's beaked whales discussed above, 
further illustrate the importance of behavioral context in 
understanding and predicting behavioral responses.
    Flight Response. A flight response is a dramatic change in normal 
movement to a directed and rapid movement away from the perceived 
location of a sound source. Relatively little information on flight 
responses of marine mammals to anthropogenic signals exist, although 
observations of flight responses to the presences of predators have 
occurred (Connor and Heithaus, 1996). Flight responses have been 
speculated as being a component of marine mammal strandings associated 
with MF active sonar activities (Evans and England, 2001). If marine 
mammals respond to Navy vessels that are transmitting active sonar in 
the same way that they might respond to a predator, their probability 
of flight responses should increase when they perceive that Navy 
vessels are approaching them directly, because a direct approach may 
convey detection and intent to capture (Burger and Gochfeld, 1981, 
1990; Cooper, 1997, 1998). In addition to the limited data on flight 
response for marine mammals, there are examples of this response in 
terrestrial species. For instance, the probability of flight responses 
in Dall's sheep Ovis dalli dalli (Frid, 2001), hauled-out ringed seals 
Phoca hispida (Born et al., 1999), Pacific brant (Branta bernicl 
nigricans), and Canada geese (B. Canadensis) increased as a helicopter 
or fixed-wing aircraft more directly approached groups of these animals 
(Ward et al., 1999). Bald eagles (Haliaeetus leucocephalus) perched on 
trees alongside a river were also more likely to flee from a paddle 
raft when their perches were closer to the river or were closer to the 
ground (Steidl and Anthony, 1996).
    Breathing. Variations in respiration naturally occur with different 
behaviors. Variations in respiration rate as a function of acoustic 
exposure can co-occur with other behavioral reactions, such as a flight 
response or an alteration in diving. However, respiration rates in and 
of themselves may be representative of annoyance or an acute stress 
response. Mean exhalation rates of gray whales at rest and while diving 
were found to be unaffected by seismic surveys conducted adjacent to 
foraging grounds (Gailey et al., 2007). Studies with captive harbor 
porpoises showed increased respiration rates upon introduction of 
acoustic alarms (Kastelein et al., 2001; Kastelein et al., 2006a) and 
emissions for underwater data transmission (Kastelein et al., 2005). 
However, exposing the same acoustic alarm to a striped dolphin under 
the same conditions did not elicit a response (Kastelein et al., 
2006a), again highlighting the importance of understanding species 
differences in the tolerance of underwater noise when determining the 
potential for impacts resulting from anthropogenic sound exposure.
    Continued Pre-disturbance Behavior and Habituation. Under some 
circumstances, some of the individual marine mammals that are exposed 
to active sonar transmissions will continue their normal behavioral 
activities. In other circumstances, individual animals will respond to 
sonar transmissions at lower received levels and move to avoid 
additional exposure or exposures at higher received levels (Richardson 
et al., 1995).
    It is difficult to distinguish between animals that continue their 
pre-disturbance behavior without stress responses, animals that 
continue their behavior but experience stress responses (that is, 
animals that cope with disturbance), and animals that habituate to 
disturbance (that is, they may have experienced low-level stress 
responses initially, but those responses abated over time). Watkins 
(1986) reviewed data on the behavioral reactions of fin, humpback, 
right and minke whales that were exposed to continuous, broadband

[[Page 19495]]

low-frequency shipping and industrial noise in Cape Cod Bay. He 
concluded that underwater sound was the primary cause of behavioral 
reactions in these species of whales and that the whales responded 
behaviorally to acoustic stimuli within their respective hearing 
ranges. Watkins also noted that whales showed the strongest behavioral 
reactions to sounds in the 15 Hz to 28 kHz range, although negative 
reactions (avoidance, interruptions in vocalizations, etc.) were 
generally associated with sounds that were either unexpected, too loud, 
suddenly louder or different, or perceived as being associated with a 
potential threat (such as an approaching ship on a collision course). 
In particular, whales seemed to react negatively when they were within 
100 m of the source or when received levels increased suddenly in 
excess of 12 dB relative to ambient sounds. At other times, the whales 
ignored the source of the signal and all four species habituated to 
these sounds. Nevertheless, Watkins concluded that whales ignored most 
sounds in the background of ambient noise, including sounds from 
distant human activities even though these sounds may have had 
considerable energies at frequencies well within the whales' range of 
hearing. Further, he noted that of the whales observed, fin whales were 
the most sensitive of the four species, followed by humpback whales; 
right whales were the least likely to be disturbed and generally did 
not react to low-amplitude engine noise. By the end of his period of 
study, Watkins (1986) concluded that fin and humpback whales have 
generally habituated to the continuous and broad-band noise of Cape Cod 
Bay while right whales did not appear to change their response. As 
mentioned above, animals that habituate to a particular disturbance may 
have experienced low-level stress responses initially, but those 
responses abated over time. In most cases, this likely means a lessened 
immediate potential effect from a disturbance. However, there is cause 
for concern where the habituation occurs in a potentially more harmful 
situation. For example, animals may become more vulnerable to vessel 
strikes once they habituate to vessel traffic (Swingle et al., 1993; 
Wiley et al., 1995).
    Aicken et al. (2005) monitored the behavioral responses of marine 
mammals to a new low-frequency active sonar system used by the British 
Navy (the United States Navy considers this to be a mid-frequency 
source as it operates at frequencies greater than 1,000 Hz). During 
those trials, fin whales, sperm whales, Sowerby's beaked whales, long-
finned pilot whales, Atlantic white-sided dolphins, and common 
bottlenose dolphins were observed and their vocalizations were 
recorded. These monitoring studies detected no evidence of behavioral 
responses that the investigators could attribute to exposure to the 
low-frequency active sonar during these trials.
    Southall et al. (2007) reviewed the available literature on marine 
mammal hearing and physiological and behavioral responses to human-made 
sound with the goal of proposing exposure criteria for certain effects. 
This peer-reviewed compilation of literature is very valuable, though 
Southall et al. (2007) note that not all data are equal: Some have poor 
statistical power, insufficient controls, and/or limited information on 
received levels, background noise, and other potentially important 
contextual variables. Such data were reviewed and sometimes used for 
qualitative illustration, but no quantitative criteria were recommended 
for behavioral responses. All of the studies considered, however, 
contain an estimate of the received sound level when the animal 
exhibited the indicated response.
    In the Southall et al. (2007) publication, for the purposes of 
analyzing responses of marine mammals to anthropogenic sound and 
developing criteria, the authors differentiate between single pulse 
sounds, multiple pulse sounds, and non-pulse sounds. LFA sonar is 
considered a non-pulse sound. Southall et al. (2007) summarizes the 
studies associated with low-frequency, mid-frequency, and high-
frequency cetacean and pinniped responses to non-pulse sounds, based 
strictly on received level, in Appendix C of their article 
(incorporated by reference and summarized in the following paragraphs).
    The studies that address responses of low-frequency cetaceans to 
non-pulse sounds include data gathered in the field and related to 
several types of sound sources, including: Vessel noise, drilling and 
machinery playback, low-frequency M-sequences (sine wave with multiple 
phase reversals) playback, tactical low-frequency active sonar 
playback, drill ships, Acoustic Thermometry of Ocean Climate (ATOC) 
source, and non-pulse playbacks. These studies generally indicate no 
(or very limited) responses to received levels in the 90 to 120 dB re: 
1 [mu]Pa range and an increasing likelihood of avoidance and other 
behavioral effects in the 120 to 160 dB re: 1 [mu]Pa range. As 
mentioned earlier, though, contextual variables play a very important 
role in the reported responses, and the severity of effects are not 
necessarily linear when compared to a received level. Also, few of the 
laboratory or field datasets had common conditions, behavioral 
contexts, or sound sources, so it is not surprising that responses 
differ.
    The studies that address responses of mid-frequency cetaceans to 
non-pulse sounds include data gathered both in the field and the 
laboratory and related to several different sound sources including: 
Pingers, drilling playbacks, ship and ice-breaking noise, vessel noise, 
Acoustic Harassment Devices (AHDs), Acoustic Deterrent Devices (ADDs), 
MF active sonar, and non-pulse bands and tones. Southall et al. (2007) 
were unable to come to a clear conclusion regarding the results of 
these studies. In some cases, animals in the field showed significant 
responses to received levels between 90 and 120 dB re: 1 [mu]Pa, while 
in other cases these responses were not seen in the 120 to 150 dB re: 1 
[mu]Pa range. The disparity in results was likely due to contextual 
variation and the differences between the results in the field and 
laboratory data (animals typically responded at lower levels in the 
field).
    The studies that address responses of high-frequency cetaceans to 
non-pulse sounds include data gathered both in the field and the 
laboratory and related to several different sound sources including: 
Pingers, AHDs, and various laboratory non-pulse sounds. All of these 
data were collected from harbor porpoises. Southall et al. (2007) 
concluded that the existing data indicate that harbor porpoises are 
likely sensitive to a wide range of anthropogenic sounds at low 
received levels (approximately 90-120 dB re: 1 [mu]Pa), at least for 
initial exposures. All recorded exposures above 140 dB re: 1 [mu]Pa 
induced profound and sustained avoidance behavior in wild harbor 
porpoises (Southall et al., 2007). Rapid habituation was noted in some 
but not all studies. There are no data to indicate whether other high-
frequency cetaceans are as sensitive to anthropogenic sound as harbor 
porpoises.
    The studies that address the responses of pinnipeds in water to 
non-pulse sounds include data gathered both in the field and the 
laboratory and related to several different sound sources including: 
AHDs, ATOC, various non-pulse sounds used in underwater data 
communication, underwater drilling, and construction noise. Few studies 
exist with enough information to include them in this analysis. The 
limited data suggest that exposure to non-pulse sounds between 90 and 
140

[[Page 19496]]

dB re: 1 [mu]Pa generally do not result in strong behavioral responses 
of pinnipeds in water, but no data exist at higher received levels.
Potential Effects of Behavioral Disturbance
    The different ways that marine mammals respond to sound are 
sometimes indicators of the ultimate effect that exposure to a given 
stimulus will have on the fitness (survival, reproduction, etc.) of an 
animal. There are few quantitative marine mammal data relating the 
exposure of marine mammals to sound to effects on reproduction or 
survival, though data exist for terrestrial species to which we can 
draw comparisons for marine mammals. Several authors have reported that 
disturbance stimuli cause animals to abandon nesting and foraging sites 
(Sutherland and Crockford, 1993); cause animals to increase their 
activity levels and suffer premature deaths or reduced reproductive 
success when their energy expenditures exceed their energy budgets 
(Daan et al., 1996; Feare, 1976; Mullner et al., 2004); or cause 
animals to experience higher predation rates when they adopt risk-prone 
foraging or migratory strategies (Frid and Dill, 2002). Each of these 
studies addressed the consequences of animals shifting from one 
behavioral state (e.g., resting or foraging) to another behavioral 
state (e.g., avoidance or escape behavior) because of human disturbance 
or disturbance stimuli.
    One consequence of behavioral avoidance results in the altered 
energetic expenditure of marine mammals because energy is required to 
move and avoid surface vessels or the sound field associated with 
active sonar (Frid and Dill, 2002). Most animals can avoid that 
energetic cost by swimming away at slow speeds or speeds that minimize 
the cost of transport (Miksis-Olds, 2006), as has been demonstrated in 
Florida manatees (Miksis-Olds, 2006).
    Those energetic costs increase, however, when animals shift from a 
resting state, which is designed to conserve an animal's energy, to an 
active state that consumes energy the animal would have conserved had 
it not been disturbed. Marine mammals that have been disturbed by 
anthropogenic noise and vessel approaches are commonly reported to 
shift from resting to active behavioral states, which would imply that 
they incur an energy cost.
    Morete et al., (2007) reported that undisturbed humpback whale cows 
that were accompanied by their calves were frequently observed resting 
while their calves circled them (milling). When vessels approached, the 
amount of time cows and calves spent resting and milling, respectively, 
declined significantly. These results are similar to those reported by 
Scheidat et al. (2004) for the humpback whales they observed off the 
coast of Ecuador.
    Constantine and Brunton (2001) reported that bottlenose dolphins in 
the Bay of Islands, New Zealand engaged in resting behavior just five 
percent of the time when vessels were within 300 m, compared with 83 
percent of the time when vessels were not present. However, Heenehan et 
al. (2016) report that results of a study of the response of Hawaiian 
spinner dolphins to human disturbance suggest that the key factor is 
not the sheer presence or magnitude of human activities, but rather the 
directed interactions and dolphin-focused activities that elicit 
responses from dolphins at rest. This information again illustrates the 
importance of context in regard to whether an animal will respond to a 
stimulus. Miksis-Olds (2006) and Miksis-Olds et al. (2005) reported 
that Florida manatees in Sarasota Bay, Florida, reduced the amount of 
time they spent milling and increased the amount of time they spent 
feeding when background noise levels increased. Although the acute 
costs of these changes in behavior are not likely to exceed an animal's 
ability to compensate, the chronic costs of these behavioral shifts are 
uncertain.
    Attention is the cognitive process of selectively concentrating on 
one aspect of an animal's environment while ignoring other things 
(Posner, 1994). Because animals (including humans) have limited 
cognitive resources, there is a limit to how much sensory information 
they can process at any time. The phenomenon called ``attentional 
capture'' occurs when a stimulus (usually a stimulus that an animal is 
not concentrating on or attending to) ``captures'' an animal's 
attention. This shift in attention can occur consciously or 
unconsciously (e.g., when an animal hears sounds that it associates 
with the approach of a predator) and the shift in attention can be 
sudden (Dukas, 2002; van Rij, 2007). Once a stimulus has captured an 
animal's attention, the animal can respond by ignoring the stimulus, 
assuming a ``watch and wait'' posture, or treating the stimulus as a 
disturbance and responding accordingly, which includes scanning for the 
source of the stimulus or ``vigilance'' (Cowlishaw et al., 2004).
    Vigilance is normally an adaptive behavior that helps animals 
determine the presence or absence of predators, assess their distance 
from conspecifics, or attend to cues from prey (Bednekoff and Lima, 
1998; Treves, 2000). Despite those benefits, vigilance comes at a cost; 
when animals focus their attention on specific environmental cues, they 
are not attending to other activities, such as foraging. These costs 
have been documented best in foraging animals, where vigilance has been 
shown to substantially reduce feeding rates (Saino, 1994; Beauchamp and 
Livoreil, 1997; Fritz et al., 2002). Animals will spend more time being 
vigilant, which may translate to less time foraging or resting, when 
disturbance stimuli approach them more directly, remain at closer 
distances, have a greater group size (e.g., multiple surface vessels), 
or when they co-occur with times that an animal perceives increased 
risk (e.g., when they are giving birth or accompanied by a calf). Most 
of the published literature suggests that direct approaches will 
increase the amount of time animals will dedicate to being vigilant. An 
example of this concept with terrestrial species involved bighorn sheep 
and Dall's sheep, which dedicated more time to being vigilant, and less 
time resting or foraging, when aircraft made direct approaches over 
them (Frid, 2001). Vigilance has also been documented in pinnipeds at 
haul out sites where resting may be disturbed when seals become alerted 
and/or flush into the water due to a variety of disturbances, which may 
be anthropogenic (noise and/or visual stimuli) or due to other natural 
causes such as other pinnipeds (Richardson et al., 1995; Southall et 
al., 2007; VanBlaricom, 2010; and Lozano and Hente, 2014).
    Several authors have established that long-term and intense 
disturbance stimuli can cause population effects by reducing the 
physical condition of individuals that have been disturbed, followed by 
reduced reproductive success, reduced survival, or both (Daan et al., 
1996; Madsen, 1994; White, 1985). For example, Madsen (1994) reported 
that pink-footed geese (Anser brachyrhynchus) in undisturbed habitat 
gained body mass and had about a 46 percent reproductive success rate 
compared with geese in disturbed habitat (being consistently scared off 
the fields on which they were foraging) which did not gain mass and had 
a 17 percent reproductive success rate. Similar reductions in 
reproductive success have been reported for other non-marine mammal 
species; for example, mule deer (Odocoileus hemionus) disturbed by all-
terrain vehicles (Yarmoloy et al., 1988), caribou (Rangifer tarandus 
caribou) disturbed by seismic exploration blasts (Bradshaw

[[Page 19497]]

et al., 1998), and caribou disturbed by low-elevation military jet 
flights (Luick et al., 1996; Harrington and Veitch, 1992). Similarly, a 
study of elk (Cervus elaphus) that were disturbed experimentally by 
pedestrians concluded that the ratio of young to mothers was inversely 
related to disturbance rate (Phillips and Alldredge, 2000).
    The primary mechanism by which increased vigilance and disturbance 
appear to affect the fitness of individual animals is by disrupting an 
animal's time budget, reducing the time they might spend foraging and 
resting (which increases an animal's activity rate and energy demand 
while decreasing their caloric intake/energy). As an example of this 
concept with terrestrial species involved, a study of grizzly bears 
(Ursus horribilis) reported that bears disturbed by hikers reduced 
their energy intake by an average of 12 kilocalories/min (50.2 x 10\3\ 
kiloJoules/min), and spent energy fleeing or acting aggressively toward 
hikers (White et al., 1999). Alternately, Ridgway et al., (2006) 
reported that increased vigilance in captive bottlenose dolphins 
exposed to sound over a five-day period in open-air, open-water 
enclosures in San Diego Bay did not cause any sleep deprivation or 
stress effects such as changes in cortisol or epinephrine levels.
    On a related note, many animals perform vital functions, such as 
feeding, resting, traveling, and socializing, on a diel cycle (24-hr 
cycle). Behavioral reactions to noise exposure (such as disruption of 
critical life functions, displacement, or avoidance of important 
habitat) are more likely to be significant for fitness if they last 
more than one diel cycle or recur on subsequent days (Southall et al., 
2007). Consequently, a behavioral response lasting less than one day 
and not recurring on subsequent days is not considered particularly 
significant unless it could directly affect reproduction or survival 
(Southall et al., 2007). It is important to note the difference between 
behavioral reactions lasting or recurring over multiple days and 
anthropogenic activities lasting or recurring over multiple days. For 
example, at-sea SURTASS LFA sonar missions last for multiple days, but 
this does not necessarily mean individual animals will be exposed to 
those exercises for multiple days or exposed in a manner that would 
result in a sustained behavioral response.
    In order to understand how the effects of activities may or may not 
impact species and stocks of marine mammals, it is necessary to 
understand not only what the likely disturbances are going to be, but 
how those disturbances are likely to affect the reproductive success 
and survivorship of individuals, and then how those impacts to 
individuals translate to population-level effects. Following on the 
earlier work of a committee of the U.S. National Research Council (NRC, 
2005), an effort by New et al. (2014) termed ``Potential Consequences 
of Disturbance (PCoD)'' outlined an updated conceptual model of the 
relationships linking disturbance to changes in behavior and 
physiology, health, vital rates, and population dynamics. In this 
framework, behavioral and physiological changes can have direct (acute) 
effects on vital rates, such as when changes in habitat use or 
increased stress levels raise the probability of mother-calf separation 
or predation; they can have indirect and long-term (chronic) effects on 
vital rates, such as when changes in time/energy budgets or increased 
disease susceptibility affect health, which then later affect vital 
rates; or they can have no effect to vital rates. In addition to 
outlining this general framework and compiling the relevant literature 
that supports it, the authors chose four example species for which 
extensive long-term monitoring data exist (southern elephant seals, 
North Atlantic right whales, Ziphidae beaked whales, and bottlenose 
dolphins) and developed state-space energetic models that can be used 
to effectively forecast longer-term, population-level impacts to these 
species from behavioral changes. While these are very specific models 
with specific data requirements that cannot yet be applied to project-
specific risk assessments or for the majority of species, they are a 
critical first step towards being able to quantify the likelihood of a 
population level effect.
Stranding and Mortality
    The definition for a stranding under the MMPA is that (A) a marine 
mammal is dead and is (i) on a beach or shore of the United States; or 
(ii) in waters under the jurisdiction of the United States (including 
any navigable waters); or (B) a marine mammal is alive and is (i) on a 
beach or shore of the United States and is unable to return to the 
water; (ii) on a beach or shore of the United States and, although able 
to return to the water, is in need of apparent medical attention; or 
(iii) in the waters under the jurisdiction of the United States 
(including any navigable waters), but is unable to return to its 
natural habitat under its own power or without assistance (16 U.S.C. 
1421h).
    Marine mammals are known to strand for a variety of reasons, such 
as infectious agents, biotoxicosis, starvation, fishery interaction, 
ship strike, unusual oceanographic or weather events, sound exposure, 
or combinations of these stressors sustained concurrently or in series. 
However, the cause or causes of most strandings are unknown (Geraci et 
al., 1976; Eaton, 1979; Odell et al., 1980; Best, 1982). Numerous 
studies suggest that the physiology, behavior, habitat relationships, 
age, or condition of cetaceans may cause them to strand or might pre-
dispose them to strand when exposed to another phenomenon. These 
suggestions are consistent with the conclusions of numerous other 
studies that have demonstrated that combinations of dissimilar 
stressors commonly combine to kill an animal or dramatically reduce its 
fitness, even though one exposure without the other does not produce 
the same result (Chroussos, 2000; Creel, 2005; Fair and Becker, 2000; 
Moberg, 2000; Relyea, 2005a; 2005b, Romero, 2004; Sih et al., 2004).
    In 1992, Congress amended the MMPA to establish the Marine Mammal 
Health and Stranding Response Program (MMHSRP) under authority of NMFS. 
The MMHSRP was created out of concern over marine mammal mortalities, 
to formalize the stranding response process, to focus efforts being 
initiated by numerous local stranding organizations, and as a result of 
public concern.
Strandings Associated With Active Sonar
    Several sources have published lists of mass stranding events of 
cetaceans in an attempt to identify relationships between those 
stranding events and military active sonar (Hildebrand, 2004; IWC, 
2005; Taylor et al., 2004). For example, based on a review of stranding 
records between 1960 and 1995, the International Whaling Commission 
(2005) concluded that, out of eight stranding events reported from the 
mid-1980s to the summer of 2003, most had been coincident with the use 
of tactical MF active sonar and most involved beaked whales. 
Differences between tactical MF sonar and SURTASS LFA sonar, as well as 
the potential for strandings due to SURTASS LFA sonar, are addressed 
further below.
    To date, there have been five stranding events coincident with 
military MF active sonar use for which NMFS and Navy concluded the 
exposure to sonar was likely a contributing factor to strandings: 
Greece (1996); the Bahamas (2000); Madeira (2000); Canary Islands 
(2002); and Spain (2006). NMFS refers the reader to DoN (2013) for a 
report on these strandings

[[Page 19498]]

associated with Navy sonar activities; Cox et al. (2006) for a summary 
of common features shared by the strandings events in Greece (1996), 
Bahamas (2000), Madeira (2000), and Canary Islands (2002); and 
Fernandez et al., (2005) for an additional summary of the Canary 
Islands 2002 stranding event. Additionally, in 2004, during the Rim of 
the Pacific (RIMPAC) exercises, between 150 and 200 usually pelagic 
melon-headed whales occupied the shallow waters of the Hanalei Bay, 
Kaua'i, Hawaii for over 28 hours. NMFS determined that the mid-
frequency sonar was a plausible, if not likely, contributing factor in 
what may have been a confluence of events that led to the Hanalei Bay 
stranding. A number of other stranding events coincident with the 
operation of MF active sonar including the death of beaked whales or 
other species (minke whales, dwarf sperm whales, pilot whales) have 
been reported; however, the majority have not been investigated to the 
degree necessary to determine the cause of the stranding. Only one of 
the events listed above was coincident with an exercise conducted by 
the U.S. Navy.
Potential for Stranding From LFA Sonar
    There is no empirical evidence of strandings of marine mammals 
associated with the employment of SURTASS LFA sonar since its use began 
in the early 2000s. Moreover, both the system acoustic characteristics 
and the operational parameters differ between SURTASS LFA sonar and MFA 
sonars. SURTASS LFA sonars use frequencies generally below 1,000 Hz, 
with relatively long signals (pulses) on the order of 60 sec; while MF 
sonars use frequencies greater than 1,000 Hz, with relatively short 
signals on the order of 1 sec. SURTASS LFA sonars involve use of one 
slower-moving vessel operating far from shore, as opposed to the 
faster-moving, multi-vessel MFA sonar training scenarios operating in 
closer proximity to shore that have been co-incident with strandings.
    As discussed previously, Cox et al. (2006) provided a summary of 
common features shared by the stranding events related to MF sonar in 
Greece (1996), Bahamas (2000), and Canary Islands (2002). These 
included deep water close to land (such as offshore canyons), presence 
of an acoustic waveguide (surface duct conditions), and periodic 
sequences of transient pulses (i.e., rapid onset and decay times) 
generated at depths less than 32.8 ft (10 m) by sound sources moving at 
speeds of 2.6 m/s (5.1 knots) or more during sonar operations (D'Spain 
et al., 2006). These features are not similar to LFA sonar activities. 
First, the Navy will not operate SURTASS LFA sonar such that RLs are 
greater than 180 dB within 22 km of any coastline, ensuring that sound 
levels are at reduced levels at a sufficient distance from land. 
Secondly, when transmitting, the ship typically operates at 1.5-2.5 m/s 
(3-5 knots), speeds that are less than those found in Cox et al. 
(2009). Finally, the center of the vertical line array (source) is at a 
depth of approximately 400 ft (121.9 m), reducing the sounds that are 
transmitted at depths above 32.8 ft (10 m). For these reasons, SURTASS 
LFA sonar cannot be operated in deep water that is close to land. Also, 
the LFA sonar signal is transmitted at depths well below 32.8 ft (10 
m). While there was an LF component in the Greek stranding in 1996, 
only MF components were present in the strandings in the Bahamas in 
2000, Madeira in 2000, and the Canary Islands in 2002. The 
International Council for the Exploration of the Sea (ICES) in its 
``Report of the Ad-Hoc Group on the Impacts of Sonar on Cetaceans and 
Fish'' raised the same issues as Cox et al., (2006) stating that the 
consistent association of MF sonar in the Bahamas, Madeira, and Canary 
Islands strandings suggest that it was the MF component, not the LF 
component, in the NATO sonar that triggered the Greek stranding of 1996 
(ICES, 2005). The ICES (2005) report concluded that no strandings, 
injury, or major behavioral change have been associated with the 
exclusive use of LF sonar.
Potential Effects of Vessel Movement and Collisions
    Vessel movement in the vicinity of marine mammals has the potential 
to result in either a behavioral response or a direct physical 
interaction. Both scenarios are discussed below.
Behavioral Responses to Vessels (Movement and Noise)
    There are limited data concerning marine mammal behavioral 
responses to vessel traffic and vessel noise, and a lack of consensus 
among scientists with respect to what these responses mean or whether 
they result in short-term or long-term adverse effects. As discussed 
previously, behavioral responses are context-dependent, complex, and 
influenced to varying degrees by a number of factors. For example, an 
animal may respond differently to a sound emanating from a ship that is 
moving towards the animal than it would to an identical received level 
coming from a vessel that is moving away, or to a ship traveling at a 
different speed or at a different distance from the animal. In cases 
where vessels actively approach marine mammals (e.g., whale watching or 
dolphin watching boats), scientists have documented that animals 
exhibit altered behavior such as increased swimming speed, erratic 
movement, and active avoidance behavior (Bursk, 1983; Acevedo, 1991; 
Baker and MacGibbon, 1991; Trites and Bain, 2000; Constantine et al., 
2003), reduced blow interval (Ritcher et al., 2003), disruption of 
normal social behaviors (Lusseau, 2003; 2006), and the shift of 
behavioral activities which may increase energetic costs (Constantine 
et al., 2003; 2004; Heenehan et al., 2016)). However, at greater 
distances, the nature of vessel movements could also potentially have 
no, or very little, effect on the animal's response to the sound. In 
those cases where there is a busy shipping lane or a large amount of 
vessel traffic, marine mammals may experience acoustic masking 
(Hildebrand, 2005) if they are present in the area (e.g., killer whales 
in Puget Sound; Foote et al., 2004; Holt et al., 2008). In any case, a 
full description of the suite of factors that elicited a behavioral 
response would require a mention of the vicinity, speed and movement of 
the vessel, and other factors. A detailed review of marine mammal 
reactions to ships and boats is available in Richardson et al. (1995). 
For each of the marine mammal taxonomy groups, Richardson et al. (1995) 
provides the following assessment regarding cetacean reactions to 
vessel traffic:
    Toothed whales: Toothed whales sometimes show no avoidance reaction 
to vessels, and may even approach them; however, avoidance can occur, 
especially in response to vessels of types used to chase or hunt the 
animals. Such avoidance may cause temporary displacement, but we know 
of no clear evidence of toothed whales abandoning significant parts of 
their range because of vessel traffic.
    Baleen whales: Baleen whales seem to ignore low-level sounds from 
distant or stationary vessels, and some whales even approach the 
sources of these sounds. When approached slowly and non-aggressively, 
whales often exhibit slow and inconspicuous avoidance maneuvers. 
However, in response to strong or rapidly changing vessel noise, baleen 
whales often interrupt their normal behavior and swim rapidly away, and 
avoidance is especially strong when a boat heads directly toward the 
whale.
    Behavioral responses to stimuli are complex and influenced to 
varying degrees by a number of factors, such as species, behavioral 
contexts, geographical regions, source

[[Page 19499]]

characteristics (moving or stationary, speed, direction, etc.), prior 
experience of the animal and physical status of the animal. For 
example, studies have shown that beluga whales' reactions varied when 
exposed to vessel noise and traffic. In some cases, naive beluga whales 
exhibited rapid swimming from ice-breaking vessels up to 80 km (49.7 
mi) away, and showed changes in surfacing, breathing, diving, and group 
composition in the Canadian high Arctic where vessel traffic is rare 
(Finley et al., 1990). In other cases, beluga whales were more tolerant 
of vessels, but responded differentially to certain vessels and 
operating characteristics by reducing their calling rates (especially 
older animals) in the St. Lawrence River where vessel traffic is common 
(Blane and Jaakson, 1994). In Bristol Bay, Alaska, beluga whales 
continued to feed when surrounded by fishing vessels and resisted 
dispersal even when purposefully harassed (Fish and Vania, 1971).
    In reviewing more than 25 years of whale observation data, Watkins 
(1986) concluded that whale reactions to vessel traffic were ``modified 
by their previous experience and current activity: habituation often 
occurred rapidly, attention to other stimuli or preoccupation with 
other activities sometimes overcame their interest or wariness of 
stimuli.'' Watkins noticed that over the years of exposure to ships in 
the Cape Cod area, minke whales changed from frequent positive interest 
(e.g., approaching vessels) to generally uninterested reactions; fin 
whales changed from mostly negative (e.g., avoidance) to uninterested 
reactions; right whales apparently continued the same variety of 
responses (negative, uninterested, and positive responses) with little 
change; and humpbacks dramatically changed from mixed responses that 
were often negative to reactions that were often strongly positive. 
Watkins (1986) summarized that whales near shore generally have become 
less wary of boats and their noises, and they have appeared to be less 
easily disturbed, even in regions with low vessel traffic. In locations 
with intense shipping and repeated approaches by boats (such as the 
whale-watching areas), more whales had positive reactions to familiar 
vessels, and they also occasionally approached other boats and yachts 
in the same ways.
    Although the radiated sound from Navy vessels will be audible to 
marine mammals over a large distance, it is unlikely that animals will 
respond behaviorally (in a manner that NMFS would consider indicative 
of harassment under the MMPA) to low-level distant ship noise as the 
animals in the area are likely to be habituated to such noises (Nowacek 
et al., 2004). In addition, given the ship movement in the water and 
the fact that it is not idle in one spot nor necessarily encircling to 
contain animals, a significant disruption of normal behavioral pattern 
that would make ship movements rise to the level of take by Level B 
harassment is unlikely. In light of these facts, NMFS does not expect 
the movements of the Navy's SURTASS LFA sonar vessels to result in take 
by Level B harassment.
Vessel Strike
    Ship strikes of cetaceans can cause immediate death or major 
injury, which may eventually lead to the death of the animal. An animal 
at the surface could be struck directly by a vessel, a surfacing animal 
could hit the bottom of a vessel, or an animal just below the surface 
could be cut by a vessel's propeller. The severity of injuries 
typically depends on the size and speed of the vessel (Knowlton and 
Kraus, 2001; Laist et al., 2001; Vanderlaan and Taggart, 2007).
    The most vulnerable marine mammals are those that spend extended 
periods of time at the surface, often to restore oxygen levels within 
their tissues after deep dives (e.g., the sperm whale). In addition, 
some large, slow moving baleen whales, such as the North Atlantic right 
whale, seem generally unresponsive to vessel sound, making them more 
susceptible to vessel collisions (Nowacek et al., 2004). Some smaller 
marine mammals (e.g., bottlenose dolphin) move quickly through the 
water column and purposefully approach ships to ride the bow wave of 
large ships without any injury.
    An examination of all known ship strikes from all shipping sources 
(civilian and military) indicates vessel speed is a principal factor in 
whether a vessel strike results in death (Knowlton and Kraus, 2001; 
Laist et al., 2001; Jensen and Silber, 2003; Vanderlaan and Taggart, 
2007). In assessing records in which vessel speed was known, Laist et 
al. (2001) found a direct relationship between the occurrence of a 
whale strike and the speed of the vessel involved in the collision, 
with most deaths occurring when a vessel was traveling in excess of 
14.9 mph (24.1 km/hr;13 kts).
    Jensen and Silber (2004) detailed 292 records of known or probable 
ship strikes of all large whale species from 1975 to 2002. Of these, 
vessel speed at the time of collision was reported for 58 cases. Of 
these cases, 39 (or 67 percent) resulted in serious injury or death (19 
of those resulted in serious injury as determined by blood in the 
water; propeller gashes or severed tailstock, and fractured skull, jaw, 
vertebrae; hemorrhaging; massive bruising or other injuries noted 
during necropsy and 20 resulted in death). Operating speeds of vessels 
that struck various species of large whales ranged from 2 to 51 kts, 
with the majority (79 percent) of these strikes occurring at speeds of 
13 kts or greater. The average speed that resulted in serious injury or 
death was 18.6 kts. Pace and Silber (2005) found that the probability 
of death or serious injury increased rapidly with increasing vessel 
speed. Specifically, the predicted probability of serious injury or 
death increased from 45 percent to 75 percent as vessel speed increased 
from 10 to 14 kts, and exceeded 90 percent at 17 kts. Higher speeds 
during collisions result in greater force of impact, but higher speeds 
also appear to increase the chance of severe injuries or death by 
pulling whales toward the vessel. While modeling studies have suggested 
that hydrodynamic forces pulling whales toward the vessel hull increase 
with increasing vessel speed (Clyne, 1999; Knowlton et al., 1995), this 
is inconsistent with Silber et al. (2010), which demonstrated that 
there is no such relationship (i.e., hydrodynamic forces are 
independent of speed).
    The Jensen and Silber (2004) report notes that the database 
represents a minimum number of collisions, because the vast majority 
probably goes undetected or unreported. In contrast, Navy vessels are 
likely to detect any strike that does occur, and they are required to 
report all ship strikes involving marine mammals. Overall, the 
percentage of Navy vessel traffic relative to overall large shipping 
vessel traffic is very small (on the order of two percent). Moreover, 
as mentioned previously, there are only four SURTASS LFA sonar vessels 
operating worldwide, which would equate to an extremely small 
percentage of the total vessel traffic.
    The Navy's operation of up to four SURTASS LFA sonar vessels 
worldwide is extremely small in scale compared to the number of 
commercial ships transiting at higher speeds in the same areas on an 
annual basis. The probability of vessel and marine mammal interactions 
occurring during SURTASS LFA sonar activities is unlikely due to the 
surveillance vessel's slow operational speed, which is typically 3.4 
mph (5.6 km/hr; 3 kts). Outside of SURTASS LFA sonar activities, each 
vessel's cruising speed would be a maximum of approximately 11.5 to 
14.9 mph (18.5 to 24.1 km/hr; 10

[[Page 19500]]

to 13 kts) which is generally below the speed at which studies have 
noted reported increases of marine mammal injury or death (Laist et 
al., 2001). Second, NMFS proposes to require the Navy to restrict the 
operation of SURTASS LFA vessels at a distance of 1 km (0.62 mi; 0.54 
nmi) seaward of the outer perimeter of any OBIA designated for marine 
mammals during a specified period, further minimizing the potential for 
marine mammal interactions. Also, the Navy would not operate SURTASS 
LFA vessels a distance of 22 km (13. mi; 12 nmi) or less of any 
coastline, including islands, thus operating in offshore coastal areas 
where lower densities of marine mammals would minimize potential for 
vessel interactions.
    As a final point, the SURTASS LFA surveillance vessels have a 
number of other advantages for avoiding ship strikes as compared to 
most commercial merchant vessels, including the following: The 
catamaran-type split hull shape and enclosed propeller system of the 
Navy's T-AGOS ships; the bridge of T-AGOS ships positioned forward of 
the centerline, offering good visibility ahead of the bow and good 
visibility aft to visually monitor for marine mammal presence; lookouts 
posted during activities scan the ocean for marine mammals and must 
report visual alerts of marine mammal presence to the Deck Officer; 
lookouts receive extensive training that covers the fundamentals of 
visual observing for marine mammals and information about marine 
mammals and their identification at sea; and SURTASS LFA vessels travel 
at low speed (3-4 kts (approximately 3.4 mph; 5.6 km/hr)) with deployed 
arrays. Lastly, the use of passive and active acoustic monitoring for 
marine mammals as mitigation measures to monitor for marine mammals 
along with visual marine mammal observers would detect cetaceans well 
in advance of any potential ship strike distance (for a thorough 
discussion of mitigation measures, please see the Proposed Mitigation 
section later in this document).
    Due to the reasons described above (low probability of vessel/
marine mammal interactions; relatively slow vessel speeds; and high 
probability of detection due to applied mitigation measures), the Navy 
and NMFS have determined that take of marine mammals by vessel strike 
is highly unlikely. Therefore, the Navy has not requested any take of 
marine mammals due to ship strike, nor is NMFS considering any 
authorization of take due to ship strike.
Results From Past Monitoring
    From the commencement of SURTASS LFA sonar use in 2002 through the 
present, neither operation of LFA sonar, nor operation of the T-AGOS 
vessels, has been associated with any mass or individual strandings of 
marine mammals temporally or spatially. In addition, the Navy's 
required monitoring reports indicate that there have been no apparent 
avoidance reactions observed, and no takes by Level A harassment due to 
SURTASS LFA sonar since its use began in 2002. Lastly, monitoring 
reports from previous years of operation indicate that the Navy 
typically transmits SURTASS LFA sonar well below the authorized number 
of hours and the actual percentages of affected stocks are well below 
the 12 percent cap for Level B harassment for each stock. In summary, 
results of the analyses conducted for SURTASS LFA sonar and more than 
thirteen years of documented operational results support the 
determination that the only takes anticipated would be short-term Level 
B harassment of relatively small percentages of affected marine mammal 
stocks.
Effects on Marine Mammal Habitat and Prey
    Based on the following information and the supporting information 
included in the Navy's application as well as the 2001; 2007; 2012; and 
2015 NEPA documents, and 2016 DSEIS/SOEIS, NMFS has preliminarily 
determined that SURTASS LFA sonar activities are not likely to 
adversely impact marine mammal habitat. For reasons described above, 
unless the sound source is stationary and/or continuous over a long 
duration in one area, the effects of the introduction of sound into the 
environment are generally considered to have a less severe impact on 
marine mammal habitat than actions involving physical alteration of the 
habitat. Marine mammals may be temporarily displaced from areas where 
SURTASS LFA activities are occurring to avoid noise exposure (see 
above), but those areas themselves will not be altered and will likely 
be available for use again after the activities have ceased or moved 
out of the area.
    The Navy's proposed SURTASS LFA sonar activities could potentially 
affect marine mammal habitat through the introduction of pressure and 
sound into the water column, which in turn could impact prey species of 
marine mammals.
Anticipated Impacts on Prey Species (Invertebrates and Fish)
    Among invertebrates, only cephalopods (octopus and squid) and 
decapods (lobsters, shrimps, and crabs) are known to sense LF sound 
(Packard et al., 1990; Budelmann and Williamson, 1994; Lovell et al., 
2005; Mooney et al., 2010). Popper and Schilt (2008) stated that, like 
fish, some invertebrate species produce sound, possibly using it for 
communications, territorial behavior, predator deterrence, and mating. 
Well known sound producers include the lobster (Panulirus spp.) (Latha 
et al., 2005), and the snapping shrimp (Alpheus heterochaelis) 
(Herberholz and Schmitz, 2001).
    Andre et al. (2011) exposed four cephalopod species (Loligo 
vulgaris, Sepia officinalis, Octopus vulgaris, and Ilex coindetii) to 
two hours of continuous sound from 50 to 400 Hz at 157  5 
dB re: 1 [mu]Pa. They reported lesions to the sensory hair cells of the 
statocysts of the exposed animals that increased in severity with time, 
suggesting that cephalopods are particularly sensitive to low-frequency 
sound. The Navy notes in the DSEIS/SOEIS (Chapter 4) that a follow-on 
study was conducted with Mediterranean and European squid (Octopus 
vulgaris, and Ilex coindetii) that included controls (Sol[eacute] et 
al., 2013), which found a similar result as Andre et al. (2011) with 
permanent and substantial alteration of the sensory hair cells of the 
statocysts. Aguilar de Soto et al. (2013) exposed New Zealand scallop 
larvae (Pecten novaezeandiae) to recorded signals from a seismic airgun 
survey every three seconds for up to 70 hours. They found a delay in 
development and malformations of the larvae in the noise-exposed 
samples. However, SURTASS LFA sonar has none of the same 
characteristics as the acoustic sources used in these studies. The time 
sequence of exposure from low-frequency sources in the open ocean would 
be about once every 10 to 15 min for SURTASS LFA. Therefore, the 
study's sound exposures were longer in duration and higher in energy 
than any exposure a marine mammal would likely ever receive and 
acoustically very different than a free field sound to which animals 
would be exposed in the real world. SURTASS LFA sonar activities would 
only be expected to have a lasting impact on these animals if they are 
within a few tens of meters from the source. In conclusion, NMFS does 
not expect any short- or long-term effects to marine mammal food

[[Page 19501]]

resources from SURTASS LFA sonar activities.
    The Navy's DSEIS/SOEIS includes a detailed discussion of the 
effects of active sonar on marine fish and several studies on the 
effects of both Navy sonar and seismic airguns that are relevant to 
potential effects of SURTASS LFA sonar on osteichthyes (bony fish). In 
the most pertinent of these, the Navy funded independent scientists to 
analyze the effects of SURTASS LFA sonar on fish (Popper et al., 2007; 
Halvorsen et al., 2006) and on the effects of SURTASS LFA sonar on fish 
physiology (Kane et al., 2010).
    Several studies on the effects of SURTASS LFA sonar sounds on three 
species of fish (rainbow trout, channel catfish, and hybrid sunfish) 
examined long-term effects on sensory hair cells of the ear. In all 
species, even up to 96 hours post-exposure, there were no indications 
of damage to sensory cells (Popper et al., 2005a, 2007; Halvorsen et 
al., 2006). Recent results from direct pathological studies of the 
effects of LFA sounds on fish (Kane et al., 2010) provide evidence that 
SURTASS LFA sonar sounds at relatively high received levels (up to 193 
dB re: 1 [mu]Pa at 1 m) have no pathological effects or short-or long-
term effects to ear tissue on the species of fish that have been 
studied.
Proposed Mitigation
Least Practicable Adverse Impact Standard Discussion
    Under section 101(a)(5)(A) of the MMPA, NMFS must set forth the 
permissible methods of taking pursuant to such activity, and other 
means of effecting the least practicable adverse impact on such species 
or stock and its habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance, and on the 
availability of such species or stock for subsistence uses (``least 
practicable adverse impact''). NMFS does not have a regulatory 
definition for least practicable adverse impact. The FY 2004 NDAA 
amended the MMPA as it relates to military readiness activities and the 
incidental take authorization process such that ``least practicable 
adverse impact'' shall include consideration of personnel safety, 
practicality of implementation, and impact on the effectiveness of the 
``military readiness activity.''
    In Conservation Council for Hawaii v. National Marine Fisheries 
Service, 97 F. Supp. 3d 1210, 1229 (D. Haw. Mar. 31, 2015), the court 
stated that NMFS ``appear[s] to think [it] satisf[ies] the statutory 
`least practicable adverse impact' requirement with a `negligible 
impact' finding.'' More recently, expressing similar concerns in a 
challenge to our last SURTASS LFA sonar incidental take rule, the Ninth 
Circuit Court of Appeals in Natural Resources Defense Council v. 
Pritzker, 828 F.3d 1125, 1134 (9th Cir. July 15, 2016), stated, 
``Compliance with the `negligible impact' requirement does not mean 
there [is] compliance with the `least practicable adverse impact 
standard [. . .] .'' As the Ninth Circuit noted in its opinion, 
however, the court was interpreting the statute without the benefit of 
NMFS' formal interpretation. We state here explicitly, as we have said 
in the past, that NMFS is in full agreement that the ``negligible 
impact'' and ``least practicable adverse impact'' requirements are 
distinct, even though both statutory standards refer to species and 
stocks. With that in mind, we provide further explanation of our 
interpretation of least practicable adverse impact, and explain what 
distinguishes it from the negligible impact standard. This discussion 
is consistent with, and expands upon, previous rules we have issued.
    Before NMFS can issue incidental take regulations under section 
101(a)(5)(A) of the MMPA, it must make a finding that the total taking 
will have a ``negligible impact'' on the affected ``species or stocks'' 
of marine mammals. NMFS' and U.S. Fish and Wildlife Service's joint 
implementing regulations for section 101(a)(5)(A) define ``negligible 
impact'' as ``an impact resulting from the specified activity that 
cannot be reasonably expected to, and is not reasonably likely to, 
adversely affect the species or stock through effects on annual rates 
of recruitment or survival.'' (50 CFR 216.103 and 50 CFR 18.27(c)) 
Recruitment (i.e., reproduction) and survival rates are used to 
determine population growth rates \1\ and, therefore are considered in 
evaluating population level impacts.
---------------------------------------------------------------------------

    \1\ A growth rate can be positive, negative, or flat.
---------------------------------------------------------------------------

    As we stated in the preamble to the final rule for the joint 
implementing regulations, not every population-level impact violates 
the negligible impact requirement. The negligible impact standard does 
not require a finding that the anticipated take will have ``no effect'' 
on population numbers or growth rates: ``The statutory standard does 
not require that the same recovery rate be maintained, rather that no 
significant effect on annual rates of recruitment or survival occurs [. 
. .]. [T]he key factor is the significance of the level of impact on 
rates of recruitment or survival.'' (See 54 FR 40338, 40341-42 
(September 29, 1989))
    While some level of impact on population numbers or growth rates of 
a species or stock may occur and still satisfy the negligible impact 
requirement--even without consideration of mitigation--the least 
practicable adverse impact provision separately requires NMFS to 
prescribe the means of ``effecting the least practicable adverse impact 
on such species or stock and its habitat, paying particular attention 
to rookeries, mating grounds, and areas of similar significance [. . 
.].'' 2 3
---------------------------------------------------------------------------

    \2\ For purposes of this discussion we omit reference to the 
language in the standard for least practicable adverse impact that 
says we also must mitigate for subsistence impacts because they are 
not at issue in this action.
    \3\ NMFS' incidental take actions routinely refer to the least 
practicable adverse impact requirement in shorthand as 
``mitigation,'' a concept that broadly encompasses measures or 
practices that are reasonably designed to avoid, reduce, or minimize 
impacts.
---------------------------------------------------------------------------

    The negligible impact and least practicable adverse impact 
standards in the statute share a common reference to ``species or 
stocks.'' A ``species'' is defined as a group of animals or plants that 
are similar and can produce young animals or plants: A group of related 
animals or plants that is smaller than a genus https://www.merriam-webster.com/dictionary/species. ``Population stock'' or ``stock'' means 
a group of marine mammals of the same species or smaller taxa in a 
common spatial arrangement, that interbreed when mature (16 U.S.C. 
1362(11)). We believe those terms indisputably refer to populations of 
animals, aFurther nd that it is therefore appropriate to view both MMPA 
provisions as having a population-level focus. This is consistent with 
both the language of the statute and Congress's overarching 
conservation objective in enacting the MMPA. See 16 U.S.C. 1361 
(Congress's findings reflecting policy concerns about the extinction or 
depletion of certain marine mammal species or stocks and the goal of 
ensuring they are functioning elements of their ecosystems).
    Recognizing this common focus of the two provisions on ``species or 
stock'' does not mean we conflate the standards; despite some common 
statutory language, we recognize the two provisions are different in 
other ways and have different functions.\4\ First, a negligible impact 
finding is required before NMFS can issue an incidental take 
authorization. Although it is

[[Page 19502]]

acceptable to use mitigation to reach a negligible impact finding (50 
CFR 216.104(c)), no amount of mitigation can enable NMFS to issue an 
incidental take authorization for an activity that still would not meet 
the negligible impact standard. Moreover, even where NMFS can reach a 
negligible impact finding--which we emphasize does allow for the 
possibility of some ``negligible'' population-level impact--the agency 
must still prescribe practicable measures that will effect the least 
amount of adverse impact upon the affected species or stock.
---------------------------------------------------------------------------

    \4\ See also CBD v. Salazar, 695 F.3d 893 (9th Cir. 2012) 
(finding that some overlap between FWS' factors for determining 
negligible impact and small numbers was not an improper conflation 
of the two standards where the agency also considered other factors 
in reaching its conclusions).
---------------------------------------------------------------------------

    Further, section 101(a)(5)(A)(i)(II) requires NMFS to issue, in 
conjunction with its authorization, binding--and enforceable--
restrictions (in the form of regulations) setting forth how the 
activity must be conducted, thus ensuring the activity has the ``least 
practicable adverse impact'' on the affected species or stocks. In 
situations where mitigation is needed to reach a negligible impact 
determination, section 101(a)(5)(A)(i)(II) also provides a mechanism 
for ensuring compliance with the ``negligible impact'' requirement. 
Finally, we also reiterate that the ``least practicable adverse 
impact'' standard requires mitigation for marine mammal habitat, with 
particular attention to rookeries, mating grounds, and other areas of 
similar significance, and for mitigating subsistence impacts; whereas 
the negligible impact standard is concerned with conclusions about the 
impact of an activity on the affected populations.\5\
    In NRDC v. Pritzker, the court stated, ``[t]he statute is properly 
read to mean that even if population levels are not threatened 
significantly, still the agency must adopt mitigation measures aimed at 
protecting marine mammals to the greatest extent practicable in light 
of military readiness needs.'' Id. At 1134 (emphasis added). This 
statement is consistent with our understanding stated above that even 
when the effects of an action satisfy the negligible impact standard 
(i.e., in the court's words, ``population levels are not threatened 
significantly''), still the agency must prescribe mitigation under the 
least practicable adverse impact standard. However, as the statute 
indicates, the focus of both standards is ultimately the impact on the 
affected ``species or stock,'' and not solely focused on/directed at 
the impact on individual marine mammals.
    We have carefully reviewed and considered the Ninth Circuit's 
opinion in NRDC v. Pritzker in its entirety. While the court's 
reference to ``marine mammals'' rather than ``marine mammal species or 
stocks'' in the italicized language above might be construed as a 
holding that the least practicable adverse impact standard applies at 
the individual ``marine mammal'' level, i.e., that NMFS must require 
mitigation to minimize impacts to each individual marine mammal unless 
impracticable, we believe such an interpretation reflects an incomplete 
appreciation of the court's holding. In our view, the opinion as a 
whole turned on the court's determination that NMFS had not given 
separate and independent meaning to the least practicable adverse 
impact standard apart from the negligible impact standard, and further 
that the court's use of the term ``marine mammals'' was not addressing 
the question of whether the standard applies to individual animals as 
opposed to the species or stock as a whole. We recognize that while 
consideration of mitigation can play a role in a negligible impact 
determination, consideration of mitigation extends beyond that 
analysis. In evaluating what mitigation is appropriate NMFS considers 
the impacts of the proposed action, the availability of measures to 
minimize those potential impacts, and the practicability of 
implementing those measures, as we describe below.

Implementation of Least Practicable Adverse Impact

    Given this most recent court decision, we further clarify how we 
determine whether a measure or set of measures meets the ``least 
practicable adverse impact'' standard. Our evaluation of potential 
mitigation measures includes consideration of two primary factors:
    (1) The manner in which, and the degree to which, implementation of 
the measure(s) is expected to reduce impacts to marine mammal species 
or stocks, their habitat, and their availability for subsistence uses 
(where relevant). Among other things, this analysis will consider the 
nature of the potential adverse impact (such as likelihood, scope, 
range), the likelihood that the measure will be effective if 
implemented; and the likelihood of successful implementation.
    (2) The practicability of the measures for applicant 
implementation. Practicability of implementation 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 (16 
U.S.C. 1371(a)(5)(A)(ii)).
    While the language of the least practicable adverse impact standard 
calls for minimizing impacts to affected species or stocks, we 
recognize that the reduction of impacts to those species or stocks 
accrues through the application of mitigation measures that limit 
impacts to individual animals. Accordingly, NMFS' analysis will focus 
on measures designed to avoid or minimize impacts on marine mammals 
from activities that are likely to increase the probability or severity 
of population-level effects. While direct evidence of impacts to 
species or stocks from a specified activity is rarely available, and 
additional study is still needed to describe how specific disturbance 
events affect the fitness of individuals of certain species, there have 
been improvements in understanding the process by which disturbance 
effects are translated to the population. With recent scientific 
advancements (both marine mammal energetic research and the development 
of energetic frameworks), the relative likelihood or degree of impacts 
on species or stocks may often be inferred given a detailed 
understanding of the activity, the environment, and the affected 
species or stocks. This same information is used in the development of 
mitigation measures and helps us understand how mitigation measures 
contribute to lessening species or stock effects.
    In the evaluation of specific measures, the details of the 
specified activity will necessarily inform each of the two factors and 
will be carefully considered to determine the types of mitigation that 
are appropriate under the least practicable adverse impact standard. 
The greater the likelihood that a measure will contribute to reducing 
the probability or severity of adverse impacts to the species or stock, 
the greater the weight that measure(s) is given when considered in 
combination with practicability to determine the appropriateness of the 
mitigation measure(s), and vice versa.
    Below we discuss how these factors are considered.
    1. Reduction of adverse impacts to species or stock. The emphasis 
given to a measure's ability to reduce the impacts on a species or 
stock considers the degree, likelihood, and context of the anticipated 
reduction of impacts to individuals as well as the status of the 
species or stock.
    The ultimate impact on any individual from a disturbance event 
(which informs the likelihood of adverse species or stock-level 
effects) is dependent on the circumstances and associated contextual 
factors, such as duration of exposure to stressors. Though any proposed 
mitigation needs to be evaluated in the context of the

[[Page 19503]]

specific activity and the species or stocks affected, measures with the 
following types of goals are often applied to reduce the likelihood or 
severity of adverse species or stock-level impacts: Avoiding or 
minimizing injury or mortality; limiting interruption of known feeding, 
breeding, mother/young, or resting behaviors; minimizing the 
abandonment of important habitat (temporally and spatially); minimizing 
the number of individuals subjected to these types of disruptions; and 
limiting degradation of habitat. Mitigating these types of effects is 
intended to reduce the likelihood that the activity will result in 
energetic or other types of impacts that are more likely to result in 
reduced reproductive success or survivorship. It is also important to 
consider the degree of impacts that were expected in the absence of 
mitigation in order to assess the added value of any potential 
measures.
    The status of the species or stock is also relevant in evaluating 
the appropriateness of certain mitigation measures in the context of 
least practicable adverse impact. The following are examples of factors 
that may (either alone, or in combination) result in greater emphasis 
on the importance of a mitigation measure in reducing impacts on a 
species or stock: The stock is known to be decreasing or status is 
unknown, but believed to be declining; the known annual mortality (from 
any source) is approaching or exceeding the potential biological 
removal (PBR) level (as defined in 16 U.S.C. 1362(20)); the affected 
species or stock is a small, resident population; or the stock is 
involved in an unusual mortality event (UME) or has other known 
vulnerabilities, such as recovering from an oil spill.
    Reduction of habitat impacts. Habitat mitigation, particularly as 
it relates to rookeries, mating grounds, and areas of similar 
significance, is also relevant and can include measures, such as 
reducing impacts of the activity on known prey utilized in the activity 
area or reducing impacts on physical habitat.
    Likely effectiveness of the measure. We consider available 
information indicating the likelihood of any measure to accomplish its 
objective. If evidence shows that a measure has not typically been 
effective or successful, then either that measure should be modified, 
or the potential value of the measure to reduce effects is lowered.
    2. Practicability. Factors considered may include 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 (16 U.S.C. 
1371(a)(5)(A)(ii)).
    The above section describes the factors considered in making a 
least practicable adverse impact finding. In summary, NMFS will 
carefully balance the likelihood and degree to which a measure will 
reduce adverse impacts on species or stocks with the measure's 
practicability in determining appropriate mitigation measures.
    As with other rulemakings for SURTASS LFA sonar, our consideration 
of mitigation under the least practicable adverse impact standard was 
conducted at scales that take into account the entire five-year 
rulemaking period and broad geographic scope of potential areas of 
SURTASS LFA sonar activities and the types of general impacts that 
could occur under the rule. Based on the types of impacts that could 
occur, and the mitigation outlined for the activities in this proposed 
rule, NMFS has preliminarily determined that the least practical 
adverse impact standard is met. Specifically, NMFS and the Navy have 
considered worldwide mitigation at the scale appropriate, given the 
available information, and have additionally considered mitigation 
recommended in a white paper, entitled, ``Identifying Areas of 
Biological Importance to Cetaceans in Data-Poor Regions'' (White 
Paper), for SURTASS LFA sonar generally, and in consideration of the 
more specific information applicable to the current proposed operating 
areas for 2017-2018. The adaptive management provisions in the proposed 
rule allow for the consideration of new information that will 
potentially support the modification of mitigation and monitoring 
measures. This information may include new science, but also may 
include additional detail regarding the operational needs of the Navy 
described in an LOA application, which could inform a more refined 
least practicable adverse impact analysis, where needed.
    The Navy has proposed to implement the following mitigation 
measures for marine mammals, most of which are included in NMFS' 
current regulations and LOAs for SURTASS LFA sonar:
    (1) LFA sonar mitigation zone--LF source transmissions are 
suspended if the Navy detects marine mammals within the 180 dB received 
level mitigation zones by any of the following detection methods:
    (a) Visual monitoring;
    (b) Passive acoustic monitoring;
    (c) Active acoustic monitoring.
    (2) Geographic restrictions such that the received level of SURTASS 
LFA sonar transmissions will not exceed 180 dB in the following areas:
    (a) Offshore Biologically Important Areas (OBIAs) during periods of 
biological importance;
    (b) Coastal Standoff Zone (22 km (12 nmi) from any land).
    Additionally, as with the previous rulemaking, NMFS proposes to 
include additional operational restrictions for SURTASS LFA sonar 
activities:
    (1) Additional 1-km buffer around the LFA sonar mitigation zone; 
and
    (2) Additional 1-km buffer around an OBIA perimeter.
    Both the Navy's proposed mitigation and NMFS' additional proposed 
mitigation are discussed in the following section.

LFA Sonar Mitigation Zone

    The Navy has proposed in its application to establish an LFA sonar 
mitigation zone corresponding to the 180-dB (RL) isopleth around the 
surveillance vessel (i.e., LFA sonar). If a marine mammal approaches or 
enters the LFA sonar mitigation zone, the Navy would implement a 
suspension of SURTASS LFA sonar transmissions. The purpose of this 
mitigation zone measure in prior rules was to reduce or alleviate the 
likelihood that marine mammals are exposed to levels of sound that may 
result in injury (PTS). However, due to the revised criteria in the 
NMFS 2016 Acoustic Technical Guidance, this mitigation zone measure 
precludes not only PTS, but also almost all TTS and higher forms of 
behavioral harassment. Thus, while not an expansion of the mitigation 
zone, this measure is now considered more effective at reducing a 
broader range of impacts compared to prior authorizations.
    Prior to commencing and during SURTASS LFA transmissions, the Navy 
will determine the propagation of LFA sonar signals in the ocean and 
the distance from the SURTASS LFA sonar source to the 180-dB isopleth 
(See Description of Real-Time SURTASS LFA Sonar Sound Field Modeling 
section). The 180-dB isopleth will define the LFA sonar mitigation zone 
for marine mammals around the surveillance vessel.
    The Navy modeling of the sound field in near-real time conditions 
provides the information necessary to modify SURTASS LFA activities, 
including the delay or suspension of LFA transmissions. Acoustic model 
updates are nominally made every 12 hours, or more frequently when 
meteorological or oceanographic conditions change. If the sound field 
criteria were exceeded, the sonar operator would notify the Officer in 
Charge (OIC), who would order the delay or suspension of transmissions. 
If

[[Page 19504]]

it were predicted that the SPLs would exceed the criteria within the 
next 12-hour period, the OIC would also be notified in order to take 
the necessary action to ensure that the sound field criteria would not 
be exceeded.
Description of Real-Time SURTASS LFA Sonar Sound Field Modeling
    This section explains how the Navy will determine the propagation 
of SURTASS LFA sonar signals in the ocean and the distance from the 
SURTASS LFA sonar source to the 180-dB re: 1 [mu]Pa isopleth (i.e., the 
basis for the proposed LFA sonar mitigation zone for marine mammals). 
NMFS provides this simplified description to aid the public's 
understanding of this action. However, the actual physics governing the 
propagation of SURTASS LFA sound signals is extremely complex and 
dependent on numerous in-situ environmental factors.
    Prior to commencing and during SURTASS LFA sonar transmissions, the 
sonar operators on the vessel will measure oceanic conditions (such as 
sea water temperature, salinity, and water depth) in the proposed 
action area. This information is required for the sonar technicians to 
accurately determine the speed at which sound travels and to determine 
the path that the sound would take through the water column at a 
particular location (i.e., the speed of sound in seawater varies 
directly with depth, temperature, and salinity).
    The sonar operators use the near real-time environmental data and 
the Navy's underwater acoustic performance prediction models (updated 
every 12 hours or more frequently when meteorological or oceanographic 
conditions change) to generate a plot of sound speed versus depth, 
typically referred to as a sound speed profile (SSP). The SSP enables 
the technicians to determine the sound field by predicting the received 
levels of sound at various distances from the SURTASS LFA sonar source 
location. Modeling of the sound field in near-real time provides the 
information necessary to modify SURTASS LFA activities, including the 
delay or suspension of LFA sonar transmissions for mitigation.

NMFS' Additional 1-km Buffer Zone Around the LFA Sonar Mitigation Zone

    As an added measure NMFS again proposes to require a buffer zone 
that extends an additional 1 km (0.62 mi; 0.54 nm) beyond the Navy's 
proposed 180-dB isopleth LFA sonar mitigation zone. This buffer 
coincides with the full detection range of the HF/M3 active sonar for 
mitigation monitoring (approximately 2 to 2.5 km; 1.2 to 1.5 mi; 1.1 to 
1.3 nmi). Thus, the 180-dB isopleth for the LFA sonar mitigation zone, 
plus NMFS' 1-km (0.54 nm) buffer zone would comprise the entire 
shutdown mitigation zone for SURTASS LFA sonar activities, wherein 
suspension of transmissions would occur if a marine mammal approaches 
or enters either zone. Implementation of this additional 1 km buffer 
zone increases the shutdown zone to approximately 2 km (1.2 mile; 1.1 
nmi) around the LFA sonar array and vessel and, given the highly 
effective monitoring capabilities (described below), will ensure that 
no marine mammals are exposed to an SPL greater than approximately 174 
dB re: 1 [mu]Pa. In past applications, the Navy has noted that this 
additional mitigation is practicable and the Navy has implemented this 
measure in previous authorizations, so it is known that the measure is 
practicable. In addition, as noted above, this mitigation is more 
effective at reducing a broader range of impacts compared to prior 
authorizations, due to the revised criteria in the NMFS 2016 Acoustic 
Technical Guidance.

Commercial and Recreational SCUBA Diving Mitigation Zone

    Navy has also proposed to establish a mitigation zone for human 
divers at 145 dB re: 1 [mu]Pa at 1 m around all known human commercial 
and recreational diving sites. Although this geographic restriction is 
intended to protect human divers, it will also reduce the LF sound 
levels received by marine mammals located in the vicinity of known dive 
sites.

Visual Mitigation Monitoring

    The use of shipboard lookouts is a critical component of most Navy 
mitigation measures. Navy shipboard lookouts are highly qualified and 
experienced observers of the marine environment. Their duties require 
that they report all objects sighted on the water surface to the Deck 
Officer (e.g., trash, a periscope, marine mammals, sea turtles) and all 
disturbances (e.g., surface disturbance, discoloration) that may be 
indicative of a threat to the vessel and its crew. There are personnel 
serving as lookouts on station at all times (day and night) when a Navy 
ship is moving through the water.
    Visual monitoring consists of daytime observations for marine 
mammals from the bridge of SURTASS LFA sonar vessels by lookouts 
(personnel trained in detecting and identifying marine mammals). The 
objective of these observations is to maintain a bearing of marine 
mammals observed and to ensure that none approach close enough to enter 
the LFA mitigation zone or the 1-km buffer zone.
    Daylight is defined as 30 min before sunrise until 30 min after 
sunset. Visual monitoring would begin 30 min before sunrise or 30 min 
before the Navy deploys the SURTASS LFA sonar array. Lookouts will 
continue to monitor the area until 30 min after sunset or until 
recovery of the SURTASS LFA sonar array.
    The lookouts would maintain a topside watch and marine mammal 
observation log during activities that employ SURTASS LFA sonar in the 
active mode. These trained monitoring personnel maintain a topside 
watch and scan the water's surface around the vessel systematically 
with standard binoculars (7x) and with the naked eye. If the lookout 
sights a possible marine mammal, the lookout will use big-eye 
binoculars (25x) to confirm the sighting and potentially identify the 
marine mammal species. Lookouts will enter numbers and identification 
of marine mammals sighted into the log, as well as any unusual 
behavior. A designated ship's officer will monitor the conduct of the 
visual watches and periodically review the log entries.
    If a lookout observes a marine mammal outside of the LFA mitigation 
or buffer zone, the lookout will notify the officer in charge (OIC). 
The OIC shall then notify the HF/M3 active sonar operator to determine 
the range and projected track of the marine mammal. If the HF/M3 sonar 
operator or the lookout determines that the marine mammal will pass 
within the LFA mitigation or buffer zones, the OIC shall order the 
delay or suspension of SURTASS LFA sonar transmissions when the animal 
enters the LFA mitigation or buffer zone to prevent Level A harassment.
    If a lookout observes a marine mammal anywhere within the LFA 
mitigation or 1-km buffer zone (as proposed by NMFS), the lookout shall 
notify the OIC who will promptly order the immediate delay or 
suspension of SURTASS LFA sonar transmissions. The lookout will enter 
his/her observations into the log. The lookout will enter these 
observations about sighted marine mammals into the log: Date/time; 
vessel name; mission area; type and number of marine mammals observed; 
assessment basis (i.e., observed injury or behavioral response); LFA 
mitigation or buffer zone radius; bearing from vessel; whether 
activities were delayed, suspended, or terminated; and relevant 
narrative information.
    Marine mammal biologists who are qualified in conducting at-sea 
marine

[[Page 19505]]

mammal visual monitoring from surface vessels shall train and qualify 
designated ship personnel to conduct at-sea visual monitoring. This 
training may be accomplished either in-person, or via video training.

Passive Acoustic Mitigation Monitoring

    For the second of the three-part mitigation monitoring measures, 
the Navy again proposes to conduct passive acoustic monitoring using 
the SURTASS towed horizontal line array to listen for vocalizing marine 
mammals as an indicator of their presence. This system serves to 
augment the visual and active sonar detection systems. If a passive 
acoustic technician detects a vocalizing marine mammal that may be 
potentially affected by SURTASS LFA sonar prior to or during 
transmissions, the technician will notify the OIC who will immediately 
alert the HF/M3 active sonar operators and the lookouts. The OIC will 
order the delay or suspension of SURTASS LFA sonar transmissions when 
the animal enters the LFA mitigation or buffer zone as detected by 
either the HF/M3 sonar operator or the lookouts. The passive acoustic 
technician will record all contacts of marine mammals into a log.

Active Acoustic Mitigation Monitoring

    HF active acoustic monitoring uses the HF/M3 sonar to detect, 
locate, and track marine mammals that could pass close enough to the 
SURTASS LFA sonar array to enter the LFA sonar mitigation or buffer 
zones. HF/M3 acoustic monitoring begins 30 min before the first SURTASS 
LFA sonar transmission of a given mission is scheduled to commence and 
continues until the Navy terminates LFA sonar transmissions.
    If the HF/M3 sonar operator detects a marine mammal contact outside 
the LFA sonar mitigation zone or buffer zones, the HF/M3 sonar operator 
shall determine the range and projected track of the marine mammal. If 
the operator determines that the marine mammal will pass within the LFA 
sonar mitigation or buffer zone, he/she shall notify the OIC. The OIC 
then immediately orders the delay or suspension of transmissions when 
the animal is predicted to enter the LFA sonar mitigation or buffer 
zone.
    If the HF/M3 sonar operator detects a marine mammal within the LFA 
mitigation or buffer zone, he/she shall notify the OIC who will 
immediately order the delay or suspension of transmissions. The HF/M3 
sonar operator will record all contacts of marine mammals into the log.
    Prior to full-power operations of the HF/M3 active sonar, and prior 
to any SURTASS LFA sonar calibrations or testing that are not part of 
regular SURTASS LFA sonar transmission, the Navy will ramp up the HF/M3 
sonar power level over a period of 5 min from the source level of 180 
dB re 1 [mu]Pa at 1 m in 10-dB increments until the system attains full 
power (if required) to ensure that there are no inadvertent exposures 
of marine mammals to received levels greater than 180 dB re 1 [mu]Pa 
from the HF/M3 sonar. The Navy will not increase the HF/M3 sonar source 
level if any of the three monitoring programs detect a marine mammal 
during ramp-up. Ramp-up may continue once marine mammals are no longer 
detected by any of the three monitoring programs.
    In situations where the HF/M3 sonar system has been powered down 
for more than 2 min, the Navy will ramp up the HF/M3 sonar power level 
over a period of 5 min from the source level of 180 dB re 1 [mu]Pa at 1 
m in 10-dB increments until the system attains full power.

Geographic Restrictions

    As noted above, the Navy again has proposed two types of geographic 
restrictions for SURTASS LFA activities in their rulemaking/LOA 
application that entail restricting SURTASS LFA sonar activities within 
these designated areas such that the SURTASS LFA sonar-generated sound 
field will not exceed 180 dB re: 1[mu]Pa (RL): (1) Establishing OBIAs 
for marine mammals; and (2) observing a coastal standoff range 
restricting SURTASS LFA sonar activities within 22 km (13. mi; 12 nmi) 
of any coastline, including islands.
    As with previous rulemakings for SURTASS LFA sonar, this proposed 
rulemaking contains a broad programmatic consideration of geographic 
restrictions, including OBIAs, in the world's oceans. However, as noted 
above, NMFS proposes to refine the process to consider additional 
geographic restrictions annually, as appropriate, based on any new 
science and the areas in which the Navy will conduct SURTASS LFA sonar 
activities in those years, as described in any subsequent LOA 
applications. The reason for this change is to allow the Navy and NMFS 
to focus on areas of Navy activities and known operational needs, and 
consideration of whether additional geographic restrictions are 
appropriate based on new information that may be available and taking 
practicability into account, at the time of the LOA application.
Offshore Biologically Important Areas
    Given the unique operational characteristics of SURTASS LFA sonar, 
Navy and NMFS developed geographical restrictions for SURTASS LFA sonar 
in the SURTASS LFA Sonar FOEIS/EIS (DoN, 2001): A 12 nmi coastal 
standoff zone where received levels from SURTASS LFA sonar could not 
exceed 180 dB and designating OBIAs wherein received levels could not 
exceed 180 dB. These areas are intended to reduce the severity and/or 
scale of impacts on affected marine mammal species or stocks by 
avoiding or minimizing impacts in areas where marine mammals are: (1) 
Known to engage in specific behaviors that lead to more severe impacts 
if interrupted; (2) known to congregate in higher densities, and; (3) 
known to have a limited range and small abundance that creates more 
vulnerability for the stock as a whole. OBIAs were defined originally 
in the 2001 SURTASS LFA Sonar FOEIS/EIS (Subchapter 2.3.2.1) as those 
areas of the world's oceans outside of the geographic stand-off 
distance (greater than 22 km (12 nmi)) from a coastline (including 
islands) where marine animals of concern (those animals listed under 
the ESA and/or marine mammals) carry out biologically important 
activities, including migration, foraging, breeding, and calving. 
Limiting activities in these important areas is expected to limit the 
likelihood or severity of species or stock effects by minimizing the 
chances that take resulting from the activity will result in 
detrimental energetic effects (such as those that could occur in known 
feeding areas) or direct interference in breeding or mother/young 
interactions (such as those that could occur in reproductive areas) 
that could translate readily to reductions in reproductive success or 
survivorship. Three OBIAs were identified in the 2001 FOEIS/EIS: 200 m 
isobaths of the east coast of North America; Costa Rica Dome; and 
Antarctic Convergence Zone. In 2007, the Navy published a supplemental 
FEIS/FOEIS that designated six new OBIAs in addition to the three OBIAs 
that were designated in the 2001 FEIS/FOEIS.
    For the 2012-2017 rule, the Deputy Assistant Secretary of the Navy 
for Environment (DASN(E)) determined that the purpose of NEPA and EO 
12114 would be furthered by the preparation of an additional 
supplemental analysis related to the employment of SURTASS LFA sonar. 
Accordingly, the DASN(E) directed that an SEIS/SOEIS (among other 
things) provide further analysis of potential additional OBIAs in 
regions of

[[Page 19506]]

the world where the Navy intends to use the SURTASS LFA sonar systems.
    In parallel, for the 2012 rule, NMFS, with Navy input, developed a 
new process and screening criteria for determining an area's 
eligibility to be considered as an OBIA nominee for marine mammals. The 
new criteria consisted of: Areas with (a) High densities of marine 
mammals; or (b) Known/defined breeding/calving grounds, foraging 
grounds, migration routes; or (c) Small, distinct populations of marine 
mammals with limited distributions. The revised biological criteria 
differed from the criteria in the 2001 FOEIS/EIS (and as continued in 
the 2007 SEIS) in two respects. First, under the 2001 FOEIS/EIS, 2007 
SEIS, and the 2007 Final Rule, an area could be designated as an OBIA 
only if it met a conjunctive test of being an area where: (1) Marine 
mammals congregate in high densities, and (2) for a biologically 
important purpose. Under the new criteria, any one of the biological 
criteria alone could be a sufficient basis for designation as an OBIA 
if it also met the geographic criterion of falling outside of 12 nmi 
(22 km) from any coastline. Second, the revised biological criteria 
included a new criterion of ``small, distinct population with limited 
distribution'' that could also, standing alone, be a basis for 
designation.
    Notably, for the 2012 FSEIS/SOEIS and 2012 rule, NMFS also 
developed and implemented a robust, systematic screening process for 
reviewing existing and potential marine protected areas against the 
OBIA criteria based on the World Database on Protected Areas (WDPA, 
2009), Hoyt (2005), and prior SURTASS LFA sonar OBIAs. This process 
produced a preliminary list of 403 OBIA nominees. As stated in the FR 
notice for the 2012 Final Rule (77 FR 50290), over 80 percent of the 
403 existing and potential marine protected areas reviewed as potential 
OBIAs (340/403) were within 12 nmi from a coastline and therefore were 
afforded protection due to the coastal standoff zone. The remaining 
areas were evaluated under the OBIA criteria, and approximately 43 
percent of these had sufficient information to be provided to subject 
matter experts (SMEs), from both within NMFS and outside of the agency, 
with expertise in the specific geographic regions to review for 
consideration of OBIAs. These SMEs provided their individual analyses 
of those areas and recommendations for additional OBIAs, resulting in a 
total of 73 potential OBIAs for consideration by the Navy and NMFS. 
Further analysis of the biological evidence and robustness of the data 
for each of these recommendations included ranking them in categories 
using a numbering system ranging from 0 to 4. Any of the nominees that 
received a ranking of 2 or higher were eligible for continued 
consideration as an OBIA nominee, which means that even areas requiring 
more data were eligible for further consideration as an OBIA. As a 
result of this process, 45 areas ranked high enough to be further 
considered as an OBIA.
    Although not part of its initial screening criteria, consideration 
of marine mammal hearing frequency sensitivity led NMFS to screen out 
areas that qualified solely on the basis of their importance for mid- 
or high-frequency hearing specialists in past rulemaking. This was due 
to the LFA sound source being below the range of best hearing 
sensitivity for most MF and HF odontocete hearing specialists. This 
means, for example, for harbor porpoises, that a sound with a frequency 
less than 1 kHz would need to be significantly louder (more than 40 dB 
louder) than a sound in their area of best sensitivity (around 100 kHz) 
in order for them to hear it. Additionally, during the 1997 to 1998 
SURTASS LFA Sonar Low Frequency Sound Scientific Research Program (LFS 
SRP), numerous odontocete and pinniped species (i.e., MF and HF hearing 
specialists) were sighted in the vicinity of the sound exposure tests 
and showed no immediately obvious responses or changes in sighting 
rates as a function of source conditions, which likely produced 
received levels similar to those that produced minor short-term 
behavioral responses in the baleen whales (i.e., LF hearing 
specialists). NMFS stated that MF and HF odontocete hearing specialists 
have such reduced sensitivity to the LFA source that limiting 
ensonification in OBIAs for those animals would not afford protection 
beyond that which is already incurred by implementing a shutdown when 
any marine mammal enters the LFA mitigation and buffer zones. 
Therefore, consideration of marine mammal frequency sensitivity led 
NMFS to screen out areas that qualified solely on the basis of their 
importance for MF or HF specialists.
    In addition to the considerations above, NMFS reviewed Hoyt (2011), 
which was an update and revision of Hoyt's 2005 earlier work, along 
with areas recommended in public comments received on the 2012 DSEIS/
SOEIS. As a result of this further analysis, NMFS concluded that there 
was adequate basis to designate 22 OBIAs for the Navy to consider for 
practicability. The OBIAs in the 2012 FSEIS/SOEIS and NMFS' proposed 
rule were: Georges Bank (year round); Roseway Basin Right Whale 
Conservation Area (Canadian restriction June through December 
annually); Great South Channel, US Gulf of Maine, and Stellwagen Bank 
NMS (January 1 to November 14 annually); Southeastern US Right Whale 
Seasonal Habitat (November 15 to April 15 annually); North Pacific 
Right Whale Critical Habitat (March through August annually); Silver 
Bank and Navidad Bank (December through April); Coastal Waters of 
Gabon, Congo and Equatorial Guinea (June through October annually); 
Patagonia and Shelf Break (year round); Southern Right Whale Seasonal 
Habitat (May through December annually); Central California NMS (June 
through November); Antarctic Convergence Zone (October through March 
annually); Piltun and Chayvo Offshore Feeding Grounds--Sea of Okhotsk 
(June through November annually); Coastal Waters off Madagascar (July 
through September and November through December annually); Madagascar 
Plateau, Madagascar Ridge, and Walters Sound (November through December 
annually); Ligurian-Corsican-Provencal Basin and Western Pelagos 
Sanctuary (July to August annually); Hawaiian Islands Humpback Whale 
NMS--Penguin Bank (November through April annually); Costa Rica Dome 
(year round); Great Barrier Reef Between (May through September 
annually); Bonney Upwelling (December through May annually); Northern 
Bay of Bengal and Head of Swatch-of-No-Ground (year round); Olympic 
Coast: The Prairie, Barkley Canyon, and Nitnat Canyon (December, 
January, March and May and June to September); and an area within the 
Southern California Bight (specifically including Tanner and Cortez 
Banks--June through November, annually). The Southern California Bight 
area was the only OBIA candidate that was operationally impracticable 
for the Navy. Therefore, 21 OBIAs were considered candidates in the 
2012 Proposed Rule. For the Final Rule, NMFS designated one additional 
OBIA (Abrolhos Bank, August through November annually), resulting in 22 
designated OBIAs for SURTASS LFA sonar.
    In response to public comments on the 2012 proposed rule, NMFS also 
reevaluated its preliminary decision not to include areas that meet the 
criteria for sperm whales and pinnipeds, and ultimately determined such 
areas would be appropriate for OBIA designation where information 
established the criteria were met, and in fact noted that OBIA 8 
(Patagonia Shelf) had already

[[Page 19507]]

been identified for elephant seals. While no OBIAs had been identified 
for sperm whales, NMFS committed to considering sperm whales in future 
analyses should supporting information become available.
    From 2012 to the present, the Navy and NMFS have maintained a list 
of potential marine areas for which information or data have not been 
sufficient to designate as OBIAs, and reviewed new literature to 
determine if additional areas should be added to the list of potential 
areas. Potential areas are periodically evaluated or re-assessed to 
determine if information and data are available to provide adequate 
support under one of the OBIA biological criteria. NMFS refers the 
reader to the Navy's 2016 SDEIS/SOEIS, subsection 4.2.2.2.5 and 
Appendix C for more detail on the analysis for potential OBIAs as part 
of this 2017 action. As part of the ongoing Adaptive Management 
component of the 2012 final rule, and in preparation for the DSEIS/
SOEIS, NMFS and Navy reviewed potential OBIAs. This process included 
conducting a comprehensive assessment of newly available peer-reviewed 
scientific data, information, or survey data on marine areas that met 
the geographic eligibility requirements for consideration as OBIAs and 
reviewing the updated WDPA (2016); 2014 United Nations List of 
Protected Areas (Deguignet et al., 2014), the Convention on Biological 
Diversity; MPA Global (Wood, 2007), the Marine Conservation Institute 
MPAtlas (2015); and cetaceanhabitat.org (see the Navy's DSEIS/OEIS, 
subsection 4.2.2.2.5 for a more detailed description of the analyses 
provided here).
    Based on this extensive review (including examination of new data 
for areas that previously did not meet the OBIA criteria), a 
preliminary list of eight new candidate OBIAs and the expansion of four 
existing OBIAs were developed and presented to SMEs for review. During 
the SME review, it was suggested that another existing OBIA be 
considered for expansion, bringing the total number of existing OBIAs 
to be considered for expansion to five.
    After additional evaluation, NMFS and Navy agreed that two of the 
new areas on the preliminary candidate list did not meet the criteria 
for designation as an OBIA. One of these (Southern Australia Southern 
Right Whale Calving Area) was determined to be solely within the 
coastal exclusion zone. The other (Tanner and Cortez Banks, which was 
included in an area considered in the original list of 22 OBIAs) was 
considered as possibly meeting the foraging biological criterion based 
on Calambokidis et al. (2015), which stated that this area represented 
a feeding area based on 52 sightings of blue whales in the region. 
However, most of these sightings occurred over 10 years ago, and the 
analysis did not consider data from satellite-tagged individuals. 
Irvine et al. (2014) used data from 171 blue whales tagged between 1993 
and 2008 to define core areas where blue whales are most likely to 
occur. Tanner and Cortez Banks were within the distributional range of 
blue whales, but residence time within the banks was not significant. 
Ongoing studies of blue whale habitat (Mate et al., 2015 and 2016) may 
or may not provide further insight into areas off the U.S. west coast 
that may meet the criteria for designation as OBIAs. Therefore, NMFS 
and Navy will continue to evaluate Tanner and Cortez Banks as a 
possible OBIA (subject to operational practicability) as new data 
become available.
    In summary, NMFS and Navy agreed to a total of six new proposed 
OBIAs and the proposed expansion of five existing OBIAs. These were 
presented to Navy for a practicability review. The Navy determined that 
there were no practicability issues related to the use of SURTASS LFA 
sonar that would affect the implementation of these OBIAs, and in fact 
agreed to observe restrictions in each of these areas near requested 
mission areas as part of their 2016-2017 LOAs under the 2012 rule while 
public review of these areas is underway as part of the NEPA process 
(DSEIS/SOEIS) and rulemaking for the 2017-2022 period. While none of 
these new OBIAs were identified specifically for sperm whales, OBIA #28 
(Perth Canyon) is designated for blue and pygmy blue whales with added 
protection for sperm whales. An area, the Hellenic Trench area in the 
Mediterranean Sea, was considered solely for sperm whales, but the core 
usage area was wholly within the coastal standoff range, so the area 
did not qualify as an OBIA based on the geographical criteria (while 
receiving similar treatment due to the fact that it was within the 
coastal standoff range).
    A comprehensive list of the resulting 28 proposed OBIAs for SURTASS 
LFA sonar, as presented in the Navy's SDEIS/SOEIS, is provided in Table 
31 below (see Navy's DSEIS/SOEIS, sections 3.3.5.3 and 4.2.2.2.5, and 
Appendix C for more detail on OBIAs).

               Table 31--Comprehensive List of Marine Mammal OBIAs Proposed for SURTASS LFA Sonar
----------------------------------------------------------------------------------------------------------------
                                                                                        OBIA
  OBIA No.       OBIA name         Location           Species       Seasonal period   boundary        Notes
                                                                                     change \1\
----------------------------------------------------------------------------------------------------------------
1..........  George's Bank...  Northwest         North Atlantic    Year-round......  R
                                Atlantic Ocean.   Right Whale.
2..........  Roseway Basin     Northwest         North Atlantic    June through
              Right Whale       Atlantic Ocean.   Right Whale.      December,
              Conservation                                          annually.
              Area.
3..........  Great South       NW Atlantic       North Atlantic    January 1-        E-CH        OBIA 3 boundary
              Channel, Gulf     Ocean/Gulf of     Right Whale.      November 14,                  revised to
              of Maine, and     Maine.                              annually.                     encompass
              Stellwagen Bank                                                                     expansion of
              NMS.                                                                                northeastern
                                                                                                  U.S. critical
                                                                                                  habitat for
                                                                                                  the North
                                                                                                  Atlantic right
                                                                                                  whale
                                                                                                  (Potential
                                                                                                  OBIA 2).
4..........  Southern U.S.     NW Atlantic       North Atlantic    November 15-      E-CH        OBIA 4 boundary
              Right Whale       Ocean.            Right Whale.      April 15,                     revised to
              Critical                                              annually.                     encompass
              Habitat.                                                                            expansion of
                                                                                                  southeastern
                                                                                                  U.S. critical
                                                                                                  habitat for
                                                                                                  the North
                                                                                                  Atlantic right
                                                                                                  whale
                                                                                                  (Potential
                                                                                                  OBIA 3).

[[Page 19508]]

 
5..........  Gulf of Alaska    Gulf of Alaska..  North Pacific     March through     E, R        OBIA 5 boundary
              \2\.                                Right Whale.      August,                       revised to
                                                                    annually.                     encompass
                                                                                                  additional
                                                                                                  foraging area
                                                                                                  for the North
                                                                                                  Pacific right
                                                                                                  whale
                                                                                                  (Potential
                                                                                                  OBIA 11).
6..........  Navidad Bank \3\  Caribbean Sea/NW  Humpback Whale..  December through  R           Silver Bank no
                                Atlantic Ocean.                     April, annually.              longer
                                                                                                  encompassed
                                                                                                  within OBIA
                                                                                                  boundary.
7..........  Coastal Waters    SE Atlantic       Humpback and      June through      R
              of Gabon,         Ocean.            Blue Whale.       October,
              Congo, and                                            annually.
              Equatorial
              Guinea.
8..........  Patagonian Shelf  SW Atlantic       Southern          Year-round.
              Break.            Ocean.            Elephant Seal.
9..........  Southern Right    SW Atlantic       Southern Right    May through       R
              Whale Seasonal    Ocean.            Whale.            December,
              Habitat.                                              annually.
10.........  Central           NE Pacific Ocean  Blue and          June through      E, R        OBIA 10
              California \4\.                     Humpback Whales.  November,                     boundary
                                                                    annually.                     revised to
                                                                                                  encompass
                                                                                                  additional
                                                                                                  foraging area
                                                                                                  for the blue
                                                                                                  and humpback
                                                                                                  whales
                                                                                                  (Potential
                                                                                                  OBIA 5).
11.........  Antarctic         Southern Ocean..  Blue, Fin, Sei,   October through   R
              Convergence                         Minke, Humpback   March, annually.
              Zone.                               Whales, and
                                                  Southern right
                                                  whale.
12.........  Pilton and        Sea of Okhotsk..  Western Pacific   June through      R
              Chayvo Offshore                     gray whale.       November,
              Feeding Grounds.                                      annually.
13.........  Coastal Waters    Western Indian    Humpback whale    July through      R
              off Madagascar.   Ocean.            and Blue whale.   September,
                                                                    annually for
                                                                    humpback whale
                                                                    breeding;
                                                                    November
                                                                    through
                                                                    December for
                                                                    migrating blue
                                                                    whales.
14.........  Madagascar        Western Indian    Pygmy blue        November through
              Plateau,          Ocean.            whale, Humpback   December,
              Madagascar                          whale, and        annually.
              Ridge, and                          Bryde's whale.
              Walters Shoal.
15.........  Ligurian-         Northern          Fin Whale.......  July to August,   R
              Corsican-         Mediterranean                       annually.
              Orovencal Basin   Sea.
              and Western
              Pelagos
              Sanctuary.
16.........  Penguin Bank,     North-Central     Humpback Whale..  November through  R
              Hawaiian          Pacific Ocean.                      April, annually.
              Islands
              Humpback Whale
              National Marine
              Sanctuary.
17.........  Costa Rica Dome.  Eastern Tropical  Blue whale and    Year-round.
                                Pacific Ocean.    Humpback whale.
18.........  Great Barrier     Coral Sea/SW      Humpback whale    May through       E, R        OBIA 18
              Reef Between.     Pacific Ocean.    and Dwarf minke   September,                    boundary
                                                  whale.            annually.                     revised to
                                                                                                  encompass
                                                                                                  additional
                                                                                                  breeding/
                                                                                                  calving area
                                                                                                  for the
                                                                                                  humpback whale
                                                                                                  (Potential
                                                                                                  OBIA 8).
19.........  Bonney Upwelling  Southern Ocean..  Blue whale,       December through  R
                                                  Pygmy blue        May, annually.
                                                  whale, and
                                                  Southern right
                                                  whale.
20.........  Northern Bay of   Bay of Bengal/N   Bryde's whale...  Year-round......  R
              Bengal and Head   Indian Ocean.
              of Swatch-of-No-
              Ground (SoNG).
21.........  Olympic Coast     NE Pacific Ocean  Humpback whale..  Olympic National
              National Marine                                       Marine
              Sanctuary and                                         Sanctuary:
              the Prairie,                                          December,
              Barkley Canyon,                                       January, March,
              and Nitnat                                            and May,
              Canyon.                                               annually; The
                                                                    Prairie,
                                                                    Barkley Canyon,
                                                                    and Nitnat
                                                                    Canyon: June
                                                                    through
                                                                    September,
                                                                    annually.
22.........  Abrolhos Bank...  Southwest         Humpback whale..  August through
                                Atlantic Ocean.                     November,
                                                                    annually.
23.........  Grand Manan       Bay of Fundy      North Atlantic    June through      ..........  Potential OBIA
              North Atlantic    (Canada).         right whale.      December,                     1; Canadian
              Right Whale                                           annually.                     critical
              Critical                                                                            habitat for
              Habitat.                                                                            the North
                                                                                                  Atlantic right
                                                                                                  whale.
24.........  Eastern Gulf of   Eastern Gulf of   Bryde's whale...  Year-round......  ..........  Potential OBIA
              Mexico.           Mexico.                                                           4.
25.........  Southern Chile    Gulf of           Blue whale......  February to       ..........  Potential OBIA
              Coastal Waters.   Corcovado,                          April, annually.              6.
                                southeast
                                Pacific Ocean
                                (SW Chile).
26.........  Offshore Sri      North-Central     Blue whale......  December through  ..........  Potential OBIA
              Lanka.            Indian Ocean.                       April, annually.              7.
27.........  Camden Sound/     Southeast Indian  Humpback whale..  June through      ..........  Potential OBIA
              Kimberly Region.  Ocean (NW                           September,                    9.
                                Australia).                         annually.

[[Page 19509]]

 
28.........  Perth Canyon....  Southeast Indian  Pygmy blue whale/ January through   ..........  Potential OBIA
                                Ocean (SW         Blue whale.       May, annually.                10.
                                Australia).
----------------------------------------------------------------------------------------------------------------
\1\ E = Expanded per data justification; E-CH = Expanded to encompass designated critical habitat; R = landward
  boundary revised per higher resolution 12-nmi data.
\2\ Name changed to indicate expansion of OBIA beyond extent of North Pacific right whale critical habitat.
\3\ Name changed to indicate that Silver Bank is no longer encompassed within OBIA boundary (instead, is
  encompassed in and afforded protection under the coastal standoff range for SURTASS LFA Sonar).
\4\ Name changed to indicate that expanded OBIA boundary is not coterminous with sanctuaries' boundaries.

NMFS' Additional 1-km Buffer Zone Around an OBIA Perimeter
    NMFS also proposes an OBIA ``buffer'' requirement that would 
restrict the operation of SURTASS LFA sonar so that the SURTASS LFA 
sonar sound field does not exceed 180 dB re: 1 [mu]Pa at a distance of 
1 km (0.62 mi; 0.54 nmi) seaward of the outer perimeter of any OBIA 
designated for marine mammals during the specified period. The Navy has 
noted in previous authorizations that this measure is practicable and 
it would adhere to this additional measure, so there would effectively 
be a 174-dB exclusion zone around any OBIA perimeter with 
implementation of this buffer.
    OBIAs are mitigation measures for SURTASS LFA sonar and are based 
on the system's unique operating and physical characteristics and 
should not be assumed to be appropriate for other activities.
Critical Habitat
    Under Section 7 of the ESA, all Federal agencies must ensure that 
any actions they authorize, fund, or carry out are not likely to 
jeopardize the continued existence of a listed species or destroy or 
adversely modify its designated critical habitat. Critical habitat is 
not designated in foreign countries or any other areas outside of U.S. 
jurisdiction. Critical habitat within the U.S. Exclusive Economic Zone 
(EEZ) has been designated for six of the 22 of the ESA-listed marine 
mammal species. Of the designated critical habitat for marine mammals, 
four areas of critical habitat are located at a distance sufficient 
from shore to potentially be affected by SURTASS LFA sonar: Critical 
habitat for the north Atlantic right whale (NARW), north Pacific right 
whale (NPRW), Hawaiian monk seal, and Steller sea lion. The Navy 
proposes that the sound field would not exceed 180 dB re: 1 [mu]Pa in 
the areas designated as critical habitat for the NARW and NPRW.
    In 2016, critical habitat for the NARW was expanded to include a 
total of 29,763 nmi\2\ (102,084 km\2\) of habitat in the Gulf of Maine 
and Georges Bank area as well as off the southeast U.S. Atlantic coast. 
The southern critical habitat area was expanded by 341 nmi (1,170 
km\2\) and includes nearshore and offshore waters from Cape Fear, NC 
south to approximately 27 nmi (50 km) south of Cape Canaveral, FL 
(NOAA, 2016). OBIAs that encompass the critical habitat for the NARW 
were established in previous rulemakings and expansion of these OBIAs 
to encompass the expanded critical habitat has been proposed in the 
Navy's 2016 SDEIS/SOEIS and rulemaking/LOA application. These existing/
proposed OBIAs encompass the critical habitats located beyond the 
coastal standoff range, including the recent critical habitat 
expansions, of the NARW on Georges Bank (OBIA #1); Roseway Basin Right 
Whale Conservation Area (OBIA #2); portions of the Great South Channel, 
Gulf of Maine, and Stellwagen Bank National Marine Sanctuary that are 
located outside of 22 km (13. mi; 12 nmi) (OBIA #3 Grand Manan NARW 
critical habitat in the Bay of Fundy (OBIA 23); and the southeastern 
U.S. NARW seasonal critical habitat (OBIA #4).
    In 2008, NMFS designated two areas of critical habitat for the 
NPRW. One of these locations is in the Bering Sea, where the Navy will 
not conduct SURTASS LFA sonar activities, and the other is in the Gulf 
of Alaska. For the designated critical habitat area in the Gulf of 
Alaska, the Navy designated an OBIA (#5) in previous rulemaking that 
bounds the designated critical habitat for the species. This OBIA is 
additionally proposed for expansion in the Navy's 2016 DSEIS/SOEIS to 
include waters beyond the critical habitat boundary where more recent 
sightings have been documented for this species.
    Much of the proposed critical habitat for Hawaiian monk seals is 
located within the coastal standoff range for SURTASS LFA sonar (22 km 
(13. mi; 12 nmi) of any land) and no existing or proposed OBIA 
encompasses the entirety of Hawaiian monk seal critical habitat. 
However, OBIA (#16) encompasses the Penguin Bank portion of the 
Hawaiian Islands Humpback Whale National Marine Sanctuary. The portion 
of the Hawaiian monk seal critical habitat that may occur beyond the 
coastal standoff range for SURTASS LFA sonar is the lowest portion of 
the water column, including the waters 33 ft (10 m) above the seafloor 
and the seafloor, seaward from certain areas of the Hawaiian Island's 
shoreline to the 656-ft (200 m) isobath.
    Much of the critical habitat for the Steller sea lion is located in 
the Bering Sea, where SURTASS LFA sonar will not operate. No proposed 
OBIA encompasses the Gulf of Alaska critical habitat for Steller sea 
lions. Although it is possible that SURTASS LFA sonar will be operated 
in the western Gulf of Alaska where the eastern critical habitat for 
the Steller sea lion is located and some of that habitat lies beyond 22 
km (13. mi; 12 nmi) from shore (i.e., the coastal standoff range for 
SURTASS LFA sonar), the water depth in which the habitat is found is 
sufficiently shallow that it is unlikely that the Navy would operate 
SURTASS LFA sonar in the vicinity.
    Both the Navy and NMFS Protected Resources Permits and Conservation 
Division are consulting with NMFS Protected Resources Interagency 
Cooperation Division on effects on critical habitat pursuant to section 
7 of the ESA.
Coastal Standoff Zone
    The Navy has proposed to restrict SURTASS LFA sonar activities 
within 22 km (13. mi; 12 nmi) of any coastline, including islands, such 
that the SURTASS LFA sonar-generated sound field will not exceed 180 dB 
re: 1 [mu]Pa (RL) at that seaward distance. This measure is intended to 
minimize both the severity and scale of effects to marine mammals by 
avoiding the higher densities of many species that may be found in 
coastal areas and it is practicable. Additionally, this restriction 
limits exposures of marine mammals to high-level sounds in the vicinity 
of geographical features that

[[Page 19510]]

have been associated with some stranding events, i.e., enclosed bays, 
narrow channels, etc.
Operational Exception
    It may be necessary for SURTASS LFA sonar transmissions to be at or 
above 180 dB re 1 [mu]Pa (rms) within the boundaries of a designated 
OBIA when: (1) Operationally necessary to continue tracking an existing 
underwater contact; or (2) operationally necessary to detect a new 
underwater contact within the OBIA. This exception will not apply to 
routine training and testing with the SURTASS LFA sonar systems.
White Paper on ``Identifying Areas of Biological Importance to 
Cetaceans in Data-Poor Regions''
    As discussed above, NMFS convened a panel of SMEs to help identify 
marine mammal OBIAs relevant to the Navy's use of SURTASS LFA sonar. 
Separately, we asked a NMFS scientist, who was also on that same panel, 
to help address a recommendation that NMFS consider a global habitat 
model (Kaschner et al., 2006) in the development of OBIAs. In addition 
to providing the requested input (which essentially concluded that 
using the Kaschner model was not advisable for several reasons), this 
NMFS scientist consulted with other NMFS scientists to provide some 
additional guidance in alternate methods for considering data poor 
areas and drafted a white paper entitled, ``Identifying Areas of 
Biological Importance to Cetaceans in Data-Poor Regions'' (White 
Paper).
    In the White Paper, the authors acknowledge that ``[m]anagement 
decisions that NMFS must make often incorporate species-specific 
information on cetacean distribution, population density, abundance, or 
ecology to identify regions of biological importance. When relevant 
cetacean data are lacking for the appropriate region or spatial scale, 
it is not acceptable to proceed in the decision making process as if 
the `no data' scenario were equivalent to `zero population density' or 
`no biological importance.' '' The authors recognize this is not an 
assumption that NMFS makes in regard to identification of OBIAs by 
stating ``[t]his is acknowledged in the screening criteria for 
identification of OBIA Nominees, which state, `For locations/regions 
and species and stocks for which density information is limited or not 
available, high density areas should be defined (if appropriate) using 
some combination of the following: Available data, regional expertise, 
and/or habitat suitability models utilizing static and/or predictable 
dynamic oceanographic features and other factors that have been shown 
to be associated with high marine mammal densities.' '' We additionally 
note here that the absence of an OBIA does not mean that NMFS assumes 
no marine mammal presence or biological importance. Even where there 
are no OBIAs, NMFS continues to impose mitigation measures (i.e., shut 
down measures with highly effective monitoring and coastal standoff 
zones) because NMFS recognizes that marine mammals could be present. 
The White Paper authors acknowledge that for much of the world's 
oceans, data on cetacean distribution or density do not exist, and 
suggest that ``[w]hen providing management advice for such data-poor 
areas, it is prudent to ask whether an analytical model should be used 
to infer patterns of distribution or density, or if a broader approach 
that incorporates expert opinion from multiple sources of information 
would be more reliable and more practical.''
    The White Paper authors considered examples of an approach relying 
on minimal information (analogous to a data-poor scenario) and provided 
Kaschner et al. (2006) as an example of such an approach. In this 
example, Kaschner et al. used models based on a synthesis of ``existing 
and often general qualitative observations about the spatial and 
temporal relationships between basic environmental conditions and a 
given species' presence'' to ``develop a generic quantitative approach 
to predict the average annual geographic ranges'' of marine mammal 
species on a global scale. Several environmental correlates including 
depth, sea surface temperature, distance to land, and mean annual 
distance to ice edge were used in the Kaschner effort. After evaluating 
four case studies from the Kaschner et al. (2006) study for predicting 
gray whale, northern right whale dolphin, North Atlantic right whale, 
and narwhal distribution, the authors of the White Paper concluded that 
`[t]he predictions from the four case studies . . . included errors of 
omission (exclusion of areas of known habitat) and commission 
(inclusion of areas that are not known to be habitat) that could have 
important implications if the model predictions alone were used for 
decision making in a conservation or management context.'' 
Specifically, the White Paper illustrated that the Kaschner et al. 
effort omitted a considerable portion of known gray whale habitat; 
overestimated the range of suitable habitat for northern right whale 
dolphins off the U.S. West Coast (noting that species-specific models 
based on dedicated shipboard surveys more correctly identified suitable 
habitat); predicted habitat for North Atlantic right whales in large 
areas where they have never been recorded; and predicted suitable 
habitat for narwhal that did not correspond with their known 
distribution. Noting these errors, the White Paper authors further make 
a distinction between a species ``fundamental niche'' (which is 
purportedly predicted by Kashner et al.'s [2006] models) and a species 
``realized niche'' (a species' observed distribution), ``which is a 
modification of the fundamental niche due to interspecific and 
intraspecific dynamics, interactions with the physical environment, and 
historical events'', and ``is typically relevant in the conservation 
and management context.'' In short, the White Paper illustrates that 
such predictive models in data-poor situations may not be the most 
appropriate methodology in the conservation and management decision 
making context due to potential errors of omission and commission and 
the differences between ``fundamental niches'' predicted by such models 
and a species' ``realized niche.'' NMFS concurred with this 
recommendation and elected not to use the Kaschner paper as a basis for 
identifying additional protective areas.
    For data-poor scenarios, the White Paper recommends considering 
general guidelines based on ecological principles to identify areas of 
biological importance and potential restriction for cetaceans. However, 
the authors conclude the White Paper by stating that ``. . . the 
question of whether the decision-making process and management actions 
should be precautionary will affect the type of guidelines that should 
be used to make inferences about cetacean density and biological 
importance in data-poor regions.''
    In NRDC v. Pritzker, referring to the White Paper, the Ninth 
Circuit stated that NMFS, in its 2012 rule, ``did not give adequate 
protection to areas of the world's oceans flagged by its own experts as 
biologically important, based on the present lack of data sufficient to 
meet the Fisheries Service's [OBIA] designation criteria, even though 
NMFS' own experts acknowledged that [f]or much of the world's oceans, 
data on cetacean distribution or density do not exist.'' NRDC v. 
Pritzker, 828 F.3d 1125 at 1142.
    In the 2012 rule, NMFS evaluated the White Paper through the lens 
of the OBIA process, which may have limited fuller consideration of the 
recommendation. Here, for this 2017

[[Page 19511]]

rulemaking, NMFS explains how it examines the White Paper's 
recommendations in the context of the least practicable adverse impact 
standard. The White Paper recommended the following general guidelines 
based on ecological principles to identify areas of biological 
importance for cetaceans:
    (1) Designation of all continental shelf waters and waters 100 km 
seaward of the continental slope as biologically important habitat for 
marine mammals;
    (2) Establishment of OBIAs within 100 km of all islands and 
seamounts that rise within 500 m of the surface; and
    (3) Nomination of high productivity regions that are not included 
in the continental shelf, continental slope, seamount, and island 
ecosystems above as biologically important areas.
    These recommendations are evaluated below in the context of the 
proposed SURTASS LFA sonar activities and the other mitigation measures 
that are proposed to minimize the impacts on the affected marine mammal 
species or stocks from these activities. To reiterate, NMFS is 
proposing several mitigation measures for SURTASS LFA sonar activities 
that: (1) Minimize or alleviate the likelihood of injury, TTS, or more 
severe behavioral responses (the 180-dB LFA mitigation zone plus 1-km 
buffer zone shutdown measure); (2) minimize or avoid behavioral impacts 
in known important areas that would have a higher potential to have 
negative energetic effects or deleterious effects on reproduction that 
could reduce the likelihood of survival or reproductive success 
(OBIAs); and (3) generally lessen the total number of takes of many 
species with coastal or shelf habitat preferences (coastal standoff). 
The nature and context of how LFA sonar is used in these activities 
(only 4 ships operating in open oceans areas and typically using active 
sonar only sporadically) is such that impacts to any individual are 
expected to be limited primarily because of the short duration of 
exposure to any individual mammal. In addition, as explained above, an 
animal would need to be fairly close to the source for the entire 
length of a transmission to experience injury; exposures occur in open 
water areas in which animals can more readily avoid the source or find 
alternate habitat relatively easily; and highly effective mitigation 
measures have been adopted that further ensure impacts are limited to 
lower-level effects with limited potential to significantly alter 
natural behavior patterns in ways that would affect the fitness of 
individuals.
    SURTASS LFA operates at 100 to 500 Hz. This frequency is far below 
the best hearing sensitivity for MF and HF species. HF species have 
their best hearing between 60 and 125 kHz (best around 100 kHz), which 
means that a sound at 500 Hz (and below) has to be at least 50 dB 
louder for HF species to hear it as well as a sound in their best 
hearing range. MF cetaceans have their best hearing between 40 and 80 
kHz (best around 55 kHz), which means that at 500 Hz and below, the 
sound has to be 40 dB louder, or more, for this group to hear the sound 
as well as a sound in their best hearing range. This means that these 
species have to be much closer to a sound to hear it, which means that, 
generally, they have to be much closer to the SURTASS sonar source for 
it to cause PTS, TTS, or a behavioral response. Additionally, during 
the 1997 to 1998 SURTASS LFA Sonar Low Frequency Sound Scientific 
Research Program (LFS SRP), numerous odontocete species (i.e., MF and 
HF hearing specialists) and pinniped species were sighted in the 
vicinity of the sound exposure tests and showed no immediately obvious 
responses or changes in sighting rates as a function of source 
conditions, which likely produced received levels similar to those that 
produced minor short-term behavioral responses in the baleen whales 
(i.e., LF hearing specialists).
    As described in the 2012 rule, NMFS believes that MF and HF 
odontocete hearing specialists have such reduced sensitivity to the LFA 
sonar source that limiting ensonification in OBIAs for those animals 
would not afford meaningful protection beyond that which is already 
incurred by implementing a shutdown when any marine mammal enters the 
LFA mitigation and buffer zones. For the same reason, our discussion of 
the White Paper recommendations will be limited to lower frequency 
sensitive species, although it is worth noting that the existing 22 km 
coastal standoff ensures a reduced number of potential takes of many MF 
and HF species with coastal habitat preferences.
    As noted previously, in evaluating how mitigation may or may not be 
appropriate to ensure the least practicable adverse impact on species 
or stocks and their habitat, we carefully balance the expected benefits 
of the mitigation measures against the practicability of 
implementation. This balancing considers the following factors: (1) The 
manner in which, and the degree to which, the implementation of the 
measure(s) is expected to reduce impacts to marine mammal species or 
stocks, their habitat, and their availability for subsistence uses 
(where relevant). Among other things, this analysis will consider the 
nature of the proposed adverse impact (likelihood, scope, range), the 
likelihood that the measure will be effective if implemented, and the 
likelihood of successful implementation; (2) the practicability of the 
measures for applicant implementation. Practicability of implementation 
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 (16 U.S.C. 1371(a)(5)(A)(ii)).
    In addition to the considerations discussed above, NMFS' evaluation 
of the recommendations of the White Paper is described below:

Continental Shelf Waters and Waters 100 km Seaward of Continental Slope

Reduction of Adverse Impacts to Marine Mammal Species and Stocks and 
Their Habitat
    The Navy already implements a coastal standoff zone of 22 km, which 
includes large parts of the continental shelf around the world, 
includes parts of the slope in some areas, and reduces potential takes 
of many marine mammal species and stocks with coastal habitat 
preferences. The White Paper provided little basis for the 100 km 
buffer seaward of the continental slope and we have found no specific 
literature to support such a broad buffer in all areas. Therefore, in 
the context of this evaluation, NMFS first considered if there was 
evidence of the importance of the continental slope itself, without any 
consideration for a buffer. In support of understanding the additional 
value of expanding this standoff to 100 km beyond the continental slope 
margin, NMFS assessed known marine mammal density information for lower 
frequency hearing specialists from the U.S. East (Roberts et al., 2016) 
and West coasts and compared these densities to bathymetry, 
specifically looking at areas of high densities compared to the 
continental shelf and slopes on both coasts (NOAA, 2009). This 
assessment and comparison focused on the U.S. East and West coasts as 
an example due to the fact that relatively more data is available for 
these waters. The comparison showed that mapped areas of highest 
densities are not always related to the slope or shelf. For example, 
while fin whales in the eastern U.S. waters show higher densities on 
the continental shelf and slope, higher densities of fin whales in 
western U.S. waters are much farther out to sea from

[[Page 19512]]

the continental shelf or slope (well beyond 100 km beyond the slope), 
and the same was found for sperm whales. Some mysticetes do show higher 
densities on the continental shelf, and some have higher densities 
along the continental slope, which may also vary among seasons (e.g., 
fin whales on the east coast). Generally, density information from the 
Atlantic showed some enhanced densities along the slope, but only for 
certain species in certain seasons, and did not indicate universally 
high densities along the slope. Humpback whales (especially around Cape 
Hatteras) seem to show some higher densities around the slope, but also 
seaward of the slope, especially in winters. However, the shelf slope 
is closer to the shore around Cape Hatteras than most places along the 
eastern seaboard, and while humpbacks may show higher densities along 
the slope in this area, the same cannot be said of humpbacks further 
south (i.e., in Florida) where the slope is much further offshore. 
Right whales show higher densities closer to shore along the Atlantic 
coast, while sperm whales are farther out past the slope on the 
Atlantic coast, as they are deep divers. Density data from the Pacific 
coast show higher densities of blue whales on the shelf and slope, 
while fin whales and sperm whales are observed in waters beyond the 
continental slope. Gray whales show higher densities closer to shore 
along the Pacific coast, while humpbacks seem to be along the slope and 
beyond in some places. Using the continental United States densities of 
these lower frequency sensitive species as examples showed that 
densities are sometimes higher within 100 km of the slope, but are 
often higher elsewhere (off the slope) and many of these high density 
areas are highly seasonal. Therefore, restricting activities within 100 
km of the entire continental shelf and slope is of limited value year-
round.
    We have emphasized in the OBIA context that although we are 
identifying ``known'' biologically important areas, other biologically 
important areas have yet to be identified, especially for data-poor 
areas. However, it is important to note that much more research is 
conducted close to shore, in the United States and other areas, and 
typically areas within 100 km of the slope are much less likely to be 
data-poor areas. NOAA, Navy, other agencies, and many independent 
researchers have been conducting marine mammal research throughout the 
U.S. EEZ (200 miles from shore) for decades. While higher densities of 
LF species may be found in some shelf and slope areas close to shore, 
which may indicate some important habitat features are present for some 
of these species, these higher densities are not associated with 
important behaviors in the same way OBIAs represent areas that are 
biologically important to a species or stock. Moreover, the prevalence 
of research makes it much less likely that important areas closer to 
shore have been missed.
    NMFS acknowledges that large ocean areas such as the continental 
shelf and slope and seamounts may exhibit habitat features that provide 
important habitat for marine mammals at certain times--as the White 
Paper states, the higher productivity in these areas could generally be 
associated with higher densities of marine mammals. However, due to the 
fact that other mitigation measures would already limit most take of 
marine mammals to lower Level B behavioral harassment, there is little 
to no indication that there is a risk to marine mammal species or 
stocks that would be avoided or lessened if waters 100 km seaward of 
the continental slope were subject to restrictions. Of note, of the 22 
OBIAs in the 2012 proposed rule, 17 of these included continental 
shelf/slope areas and similar coastal waters. In addition, these waters 
of the continental shelf/slope would be afforded significant protection 
due to the coastal standoff mitigation measure.
    Given the mitigation measures already in place, and proposed for 
this rule, that would limit most takes of marine mammals to lower Level 
B behavioral harassment, the only additional benefit to restricting 
activities in continental shelf waters and waters 100 km seaward of 
continental slope would be a further, though not significant, reduction 
in these lower level behavioral takes in those areas. As discussed 
above, not all behavioral responses may result in take and not all 
behavioral takes necessarily result in fitness consequences to 
individuals that have the potential to translate to population 
consequences to the species or stock. For example, energetic costs of 
short-term intermittent exposures would be unlikely to affect 
individuals such that vital rates of the population are affected.
    In addition to the mitigation measures in place, and proposed 
again, for SURTASS LFA sonar use that would already provide protection 
for continental shelf/slope waters, it is important to note that there 
are a total of four SURTASS LFA sonar ships that would each be 
operating up to a maximum of 255 transmission hours per year (amounting 
to approximately 40 days maximum of LFA, which is spread over the 
entire year). It is not known, nor does the Navy indicate in its plans, 
that activities of these four vessels would be focused in any specified 
area. It is likely, based on past monitoring reports, that the 
activities of these four vessels are spread out and would not 
necessarily overlap marine mammal high-density areas for an extended 
period of time. Although some LFA sonar activities could, on occasion, 
overlap marine mammal high-density areas, the Navy is still bound by 
the 12% cap on Level B takes per marine mammal stock annually. However, 
because areas of marine mammal high density are dispersed over large 
ocean areas for each species, it is certain that LFA sonar would not 
implicate all of these areas for a given species or stock in any year. 
Given the expanse of these areas (e.g., entire eastern and western 
coast of the U.S. for continental shelf/slope), even if part of the 
area would be exposed to LFA sonar, there would still be ample similar 
habitat areas available for species/stocks if it were preferred 
habitat.
Practicability
    NMFS and the Navy evaluated the practicability of implementation of 
the White Paper's recommended continental shelf, slope, and 100-km 
seaward The Navy has indicated, and NMFS concurs, that additional 
continental shelf, slope, and 100 km seaward restrictions beyond the 
existing coastal standoff and OBIAs would unacceptably impact the 
Navy's national security mission as large areas of the ocean would be 
restricted where targets of interest may operate. The mission of 
SURTASS LFA sonar is to detect quieter and harder to-find foreign 
submarines at greater distances. For the system to perform its national 
defense function, the Navy must operate within coastal, littoral waters 
in order to track relevant targets. The Navy has indicated that if 
large areas of the continental shelf or slope were restricted, the Navy 
would not have the benefit of being able to train and operate in these 
challenging environments, while adversaries would use these distinctive 
geographic features to their advantage. Year-round access to all of 
these areas of challenging topography and bathymetry is necessary as 
the Navy cannot telegraph to potential adversaries that it will not be 
operating in large parts of the ocean for long periods of time.
Conclusion
    In summary, while restricting SURTASS LFA sonar use in waters 100 
km seaward from the continental slope could potentially reduce 
individual exposures or behavioral responses for

[[Page 19513]]

certain species and potentially provide some additional protection of 
preferred habitat in some cases, density data indicates that certain 
mysticetes and sperm whales have higher densities in areas other than 
the continental slope. Therefore, limiting activities in these large 
areas when activities are comparatively low (no more than four ships 
each operating up to a maximum of 255 transmission hours spread across 
expansive distances and over the course of an entire year), and the 
existing risks to the affected species and stocks are low, would 
provide limited discernible benefit. This is especially true given that 
many mysticete species have latitudinal seasonal movements that would 
render these large areas of less, or no, importance to these species in 
certain portions of the year. Given the limited potential for 
additional reduction of impacts to marine mammal species beyond what 
the existing mitigation measures described in this proposed rule 
provide, and the high degree of impracticability (significant impacts 
on mission effectiveness), NMFS has preliminarily determined that this 
measure is not required.

Restrictions Within 100 km of All Islands and Seamounts That Rise to 
Within 500 m of the Surface

Reduction of Adverse Impacts to Marine Mammal Species and Stocks and 
Their Habitat
    Currently, waters surrounding all islands are already protected by 
the coastal standoff zone (22km). As discussed previously, this means 
that SURTASS LFA sonar received levels would not exceed 180 dB re 
1[mu]Pa within 22 km (12 nmi) from the coastline. This 22 km coastal 
standoff was determined in previous analyses (DoN, 2007) to result in 
the lowest potential risk to marine species, particularly marine 
mammals. Morato et al. (2010) state that seamounts were found to have 
higher species diversity within 30-40 km of the summit, and tended to 
aggregate some visitor species (Morato et al., 2008). However, the 
authors did not demonstrate that this behavior can be generalized to be 
universally applicable to all species at all times.
    Morato et al. (2008) examined seamounts for their effect on 
aggregating visitors and noted that seamounts may act as feeding 
stations for some visitors, but not all seamounts seem to be equally 
important for these associations. While Morato et al. (2008) only 
examined seamounts in the Azores, the authors noted that only seamounts 
shallower than 400 m depth showed significant aggregation effects. 
Their results indicated that some marine predators (common dolphin 
(Delphinus delphis) and other non-marine mammal species such as fish 
and invertebrates) were significantly more abundant in the vicinity of 
some shallow-water seamount summits, there was no demonstrated seamount 
association for bottlenose dolphins (Tursiops truncatus), spotted 
dolphin (Stenella frontalis), or sperm whales (Physeter macrocephalus).
    Along the northeastern U.S. continental shelf, cetaceans tend to 
frequent regions based on food preferences (i.e., areas where preferred 
prey aggregate), with picscivores (fish-eating; e.g., humpback, fin, 
and minke whales as well as bottlenose, Atlantic white-sided, and 
common dolphins) being most abundant over shallow banks in the western 
Gulf of Maine and mid-shelf east of Chesapeake Bay; planktivores 
(plankton-eating; e.g., right, blue, and sei whales) being most 
abundant in the western Gulf of Maine and over the western and southern 
portions of Georges Bank; and teuthivores (squid eaters, e.g., sperm 
whales) most abundant at the shelf edge (Fiedler, 2002). While there 
have been observations of humpback whales lingering at seamounts (Mate 
et al., 2007), the purpose of these aggregations is not clear, and it 
may be that they are feeding, regrouping, or simply using them for 
navigation between feeding and breeding grounds (Fiedler, 2002; Mate et 
al., 2007); therefore, the role of the seamount habitat is not clear. 
According to Pitcher et al. (2007), there have been very few 
observations of persistently high phytoplankton biomass (i.e., high 
primary production, usually estimated from chlorophyll concentrations) 
over seamounts and, where such effects have been reported, all were 
from seamounts with summits shallower than 300 m and the effects were 
not persistent, lasting only a few days at most. Therefore, it may be 
that food sources for many baleen whales are not concentrated in great 
enough quantities for significant enough time periods to serve as 
important feeding areas. While some odontocete (toothed) whales have 
been suggested to utilize seamount features for prey capture (Pitcher 
et al. (2007)), the authors conclude that the available evidence 
suggests that, ``unlike many other members of seamount communities, the 
vast majority of marine mammal species are probably only loosely 
associated with particular seamounts.''
Practicability
    NMFS and the Navy evaluated the practicability of implementation of 
the White Paper's recommendation regarding seamounts that rise to 
within 500 m of the sea surface. The Navy has indicated, and NMFS 
concurs, that additional restrictions within 100 km of all islands and 
seamounts that rise to within 500 m of the surface beyond the existing 
coastal standoff and OBIAs would unacceptably impact their national 
security mission. The mission of SURTASS LFA sonar is to detect quieter 
and harder to-find foreign submarines at greater distances. Seamounts 
provide complex bathymetric and oceanographic conditions that can be 
used by submarines to hide and avoid detection. Training, testing and 
operations in and around seamounts is vitally important for the Navy to 
understand how these features can be exploited to evade detection. If 
the Navy's use of SURTASS was restricted within 100 km of these 
features, the Navy would not have the benefit of being able to train 
and operate in these challenging environments, while adversaries would 
use these distinctive geographic features to their advantage. Year-
round access to all of these areas of challenging topography and 
bathymetry is necessary, as the Navy cannot telegraph to potential 
adversaries that it will not be operating in specific seamounts areas 
for long periods of time.
Conclusion
    In summary, while restricting LFA sonar use in areas 100 km seaward 
from islands and seamounts could potentially reduce take numbers for 
some individuals within a limited number of species and potentially 
provide some additional protection of preferred habitat in some cases 
(potential feeding), data indicate that marine mammal associations with 
these areas are limited, and the benefits would be, at best, ephemeral. 
Furthermore, the potential avoidance would likely be more associated 
with mid-frequency and high frequency species, while low frequency 
species are more of a concern for potential effects. Limiting SURTASS 
LFA sonar activities in these large areas when activities are already 
comparatively low (four ships each operating a maximum of 255 
transmission hours spread across expansive distances and an entire 
year), and the existing risks to the affected species and stocks are 
comparatively low (limited to lower level Level B behavioral 
harassment), would provide limited additional benefit to individual 
marine mammals, but would not change the effect on the population, 
species, or stock. Given the limited potential for additional reduction 
of impacts to a

[[Page 19514]]

small number of marine mammal species and the high degree of 
impracticability (serious impacts on mission effectiveness), NMFS has 
preliminarily determined that this measure should not be required.

High Productivity Regions That Are Not Included in the Continental 
Shelf, Continental Slope, Seamount, and Island Ecosystems

Reduction of Adverse Impacts to Marine Mammal Species and Stocks and 
Their Habitat
    Regions of high productivity have the potential to be important 
foraging habitat for some species of marine mammals at certain times of 
the year and could potentially correlate with either higher densities 
and/or feeding behaviors through parts of their area. Productive areas 
of the ocean are difficult to consistently define due to interannual 
spatial and temporal variability. High productivity areas have 
ephemeral boundaries that are difficult to define and do not always 
persist interannually or within the same defined region. While there is 
not one definitive guide to the productive areas of the oceans, NMFS 
and the Navy examined these areas in the 2017/2018 SURTASS operation 
area.
    These areas are typically very large, which means that animals are 
not constrained in high densities in a particular feeding area and 
there are typically ample alternative opportunities to move into, or 
within, other parts of these high productivity areas should they choose 
to avoid the area around the SURTASS vessel. Additionally, these areas 
are often associated with coastal areas, for instance, Houston and 
Wolverton (2009) show areas of high/highest productivity that are 
either (1) confined to high latitude (polar) areas that are not in the 
SURTASS LFA sonar operational area, or (2) very coastally and typically 
seasonally associated with areas of high coastal run off (i.e.. by 
mouth of Mississippi River, mouth of Amazon river), which are already 
encompassed by the coastal standoff range. Additionally, as noted 
above, given the current mitigation scheme for SURTASS LFA sonar, the 
existing risk to marine mammal species and stocks is low and is limited 
to Level B harassment (significant disruption or abandonment of 
behavioral patterns) due to existing mitigation measures.
Practicability
    NMFS and the Navy evaluated the practicability of implementation of 
the White Paper's recommended restrictions on high productivity. The 
Navy has indicated, and NMFS concurs, that additional restrictions in 
high productivity regions that are not included in the continental 
shelf, continental slope, seamount, and island ecosystems beyond the 
existing coastal standoff and OBIAs would unacceptably impact their 
national security mission. The mission of SURTASS LFA sonar is to 
detect quieter and harder to-find foreign submarines at greater 
distances. For the system to perform its national defense function, the 
Navy must operate within coastal, littoral waters, which may include 
high productivity areas, in order to track relevant targets. If large 
areas of the ocean were excluded from potential usage, the Navy would 
not have the benefit of being able to train and operate in these 
challenging environments, while adversaries would use these distinctive 
geographic features to their advantage. Year-round access to all of 
these areas of challenging topography and bathymetry is necessary as 
the Navy cannot telegraph to potential adversaries that it will not be 
operating in large parts of the ocean for long periods of time. Also, 
because high productivity areas are highly variable and ephemeral, 
implementation would not be operationally practicable for the Navy.
Conclusion
    Restricting use of SURTASS LFA sonar seasonally in high 
productivity areas could potentially reduce take numbers for certain 
species and potentially provide some additional protection of preferred 
or feeding habitat in some cases. However, as noted above, the size of 
the primary productivity areas is such that animals could likely easily 
access adjacent high productivity areas should they be temporarily 
diverted away from a particular area due to a SURTASS LFA sonar source. 
In addition, marine mammals are certainly not concentrated through all 
or even most of these large areas for all or even most of the time when 
productivity is highest, so a broad limitation of this nature would 
likely unnecessarily limit LFA sonar activities while providing 
negligible protective benefits to marine mammal species or stocks. 
Limiting activities in these large areas when activities are already 
comparatively low (four ships operating approximately 255 transmission 
hours spread across expansive ocean distances), and the existing risks 
to the affected species and stocks are comparatively low, would provide 
limited additional protection. Given the limited potential for 
additional reduction of impacts to marine mammal species and the high 
degree of impracticability (serious impacts on mission effectiveness), 
NMFS has preliminarily determined that this measure would not be 
required.
White Paper Overall Conclusion
    In conclusion, NMFS has considered the White Paper recommendations. 
While we acknowledge that these measures could potentially reduce the 
numbers of take for some individual marine mammals within a limited 
number of species, or may add some small degree of protection to 
preferred habitat or feeding behaviors in certain circumstances, this 
limited and uncertain benefit to the affected species or stocks and 
their habitat is not justified when considered against the degree of 
impracticability for Navy implementation. This is especially true in 
light of the operational impacts and the anticipated success of the 
significant mitigation measures that the Navy has already been 
implementing (and which have provided a large degree of protection and 
have limited takes to lower level Level B behavioral harassment) to 
reduce impacts.
Overall Mitigation Conclusions
    NMFS has determined preliminarily that the Navy's proposed 
mitigation measures together with the additional mitigation measures 
proposed by NMFS provide the means of effecting the least practicable 
adverse impacts on marine mammals species or stocks and their habitat, 
paying particular attention to rookeries, mating grounds, and areas of 
similar significance, and which include consideration of personnel 
safety, practicality of implementation, and impact on the effectiveness 
of the military readiness activity. NMFS provides further details in 
the following section.
    NMFS believes that the shutdown in the LFA sonar mitigation and 
buffer zones, based on detection from highly effective visual 
monitoring, passive acoustic monitoring, active acoustic monitoring 
using HF/M3 sonar with ramp-up procedures, and geographic restriction 
measures proposed will enable the Navy to: (1) Avoid Level A harassment 
of marine mammals; (2) minimize the incidences of marine mammals 
exposed to SURTASS LFA sonar sound levels associated with TTS and 
higher levels of significant behavioral disruptions under Level B 
harassment; ands; and (3) minimize exposure of marine mammal takes in 
areas and during times of important behaviors, such as feeding, 
migrating, calving, or breeding based on the best available 
information.

[[Page 19515]]

    The SURTASS LFA sonar signal is not expected to cause mortality, 
serious injury, PTS, or TTS due to implementation of the shutdown zone 
mitigation measures, which include the Navy's proposed 180 dB rms 
isopleth shutdown zone (LFA Mitigation Zone) as well as an additional 1 
km buffer proposed by NMFS. Although the distance to the 180 dB 
isopleth is based on existing environmental conditions, the distance is 
frequently, but not always, approximately 1 km. Implementing an 
additional 1-km buffer zone increases the extent around the LFA sonar 
array and vessel, which will ensure that no marine mammals are exposed 
to an SPL greater than about 174 dB re: 1 [mu]Pa rms. As shown in Table 
29 above, the TTS threshold for LF cetaceans, which are the hearing 
group most likely affected by SURTASS LFA sonar, is 179 dB SEL. A low-
frequency cetacean would need to remain within 41 meters (135 ft) for 
an entire LFA sonar transmission (60 seconds) to potentially experience 
PTS and within 413 m (1,345 ft) for an entire LFA sonar transmission 
(60 seconds) to potentially experience TTS. Therefore, implementation 
of the shutdown zone mitigation measures would minimize the potential 
for LF cetaceans to be exposed to LFA sonar at levels associated with 
the onset of TTS. The best information available indicates that effects 
from SPLs less than 180 dB re: 1 [mu]Pa will be limited to short-term, 
Level B behavioral harassment, and animals are expected to return to 
behaviors shortly after exposure.
    As described above, NMFS has included a robust suite of mitigation 
measures for world-wide SURTASS LFA sonar operation that: Minimize or 
alleviate the likelihood of injury, TTS, or more severe behavioral 
responses due to implementation of shutdown measures (implementation of 
the LFA mitigation zone plus a 1 km buffer); minimize or avoid 
behavioral impacts in important areas where these impacts would be more 
likely to have negative energetic effects, or deleterious effects on 
reproduction, which could reduce the likelihood of survival or 
reproductive success (measures to avoid or lessen exposures of marine 
mammals within OBIAs); and generally lessen the total number of takes 
of many species due to implementation of coastal standoff measures. 
These measures, taken together, constitute the means of effecting the 
least practicable adverse impact on the affected species and stocks 
worldwide and for operating areas in the upcoming annual LOA period. We 
also carefully evaluated the potential inclusion of additional measures 
in data-poor areas (White Paper recommendations) before reaching this 
conclusion. With regard to habitat, NMFS has not identified any impacts 
to habitat from SURTASS LFA sonar that persist beyond the time and 
space that the impacts to marine mammals themselves could occur. 
Therefore, the mitigation measures that address important areas that 
serve as important habitat for marine mammals in all or part of the 
year (i.e., OBIAs and the coastal standoff), appropriately address 
effects on marine mammal species and stocks and their habitat.
    In the 2012 rule, NMFS and the Navy annually considered how new 
information, from anywhere in the world, should be considered in an 
adaptive management context--including whether this new information 
would support the identification of new OBIAs or other mitigation 
measures. Moving forward, new information will still be considered 
annually, but only in the context of the area in which SURTASS LFA 
assets will be operating in that year. This approach makes sense 
because it is not possible to conduct a meaningful practicability 
analysis on a measure in an area where SURTASS is not deployed and 
there are no real details to apply to the analysis. Additionally, 
evaluating potential additional measures in areas that will not be used 
is not a good use of agency resources. Should SURTASS LFA sonar deploy 
to new action areas during the time period covered by this proposed 
rule, NMFS will reconsider the recommendations made in the White Paper 
in the context of those specific areas and operational considerations 
in advance of any potential LOA issuance in that area, and publish our 
evaluation in the associated FR notice.

Proposed Monitoring

    Section 101(a)(5)(A) of the MMPA states that in order to issue an 
ITA for an activity, NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking.'' The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for LOAs 
must include the suggested means of accomplishing the necessary 
monitoring and reporting that will result in increased knowledge of the 
species, the level of taking, or impacts on populations of marine 
mammals that are expected to be present.
    Monitoring measures prescribed by NMFS should accomplish one or 
more of the following general goals:
     An increase in our understanding of how many marine 
mammals are likely to be exposed to levels of LFA sonar that we 
associate with specific adverse effects, such as disruption of 
behavioral patterns and TTS (Level B harassment), or PTS.
     An increase in our understanding of how individual marine 
mammals respond (behaviorally or physiologically) to LFA sonar (at 
specific received levels or other stimuli expected to result in take).
     An increase in our understanding of how anticipated takes 
of individuals (in different ways and to varying degrees) may impact 
the population, species, or stock (specifically through effects on 
annual rates of recruitment or survival).
     An increase in knowledge of the affected species.
     An increase in our understanding of the effectiveness of 
certain mitigation and monitoring measures.
     A better understanding and record of the manner in which 
the authorized entity complies with the incidental take authorization.
     An increase in the probability of detecting marine 
mammals, both within the mitigation zone (thus allowing for more 
effective implementation of the mitigation) and in general to better 
achieve the above goals.
    In addition to the real-time monitoring associated with mitigation, 
the Navy is engaging in exploring other monitoring efforts described 
here:

Marine Mammal Monitoring (M3) Program

    The Marine Mammal Monitoring (M3) Program uses the Navy's fixed and 
mobile passive acoustic monitoring systems to monitor the movements of 
some large cetaceans (principally baleen whales), including their 
migration and feeding patterns, by tracking them through their 
vocalizations.
    At present, the M3 Program's data are classified, as are the data 
reports created by M3 Program analysts, due to the inclusion of 
sensitive national security information. The Navy (OPNAV N2/N6F24) 
continues to assess and analyze M3 Program data collected from Navy 
passive acoustic monitoring systems and is working toward making some 
portion of that data (after appropriate security reviews) available to 
scientists with appropriate clearances and ultimately to the public 
(D0N, 2015). Progress has been achieved on addressing securing concerns 
and declassifying the results of a specific dataset pertinent to a 
current area of scientific inquiry for which a peer-reviewed scientific 
paper is being prepared for submission to a scientific journal.

[[Page 19516]]

    Due to research indicating that beaked whales and harbor porpoises 
may be particularly sensitive to a range of underwater sound (Southall 
et al., 2007; Tyack et al., 2011; Kastelein et al., 2012), in the 2012 
rule and LOAs for these activities, NMFS included conditions for 
understanding of the potential effects of SURTASS LFA sonar on these 
taxa. The Navy convened an independent Scientific Advisory Group (SAG), 
whose purpose was to investigate and assess different types of research 
and monitoring methods that could increase the understanding of the 
potential effects to beaked whales and harbor porpoises from exposure 
to SURTASS LFA sonar transmissions. The SAG was composed of six 
scientists affiliated with two universities, one Federal agency (NMFS), 
and three private research and consultancy firms. The SAG prepared and 
submitted a report, entitled, ``Potential Effects of SURTASS LFA Sonar 
on Beaked Whales and Harbor Porpoises,'' describing the SAG's 
monitoring and research recommendations. In August 2013, the SAG report 
was submitted to the Navy, NMFS, and the Executive Oversight Group 
(EOG) for SURTASS LFA sonar.
    The EOG is comprised of representatives from the U.S. Navy (Chair, 
OPNAV N2/N6F24), Office of the Deputy Assistant Secretary of the Navy 
for the Environment, Office of Naval Research, Navy Living Marine 
Research Program, and the NMFS Office of Protected Resources (OPR) 
(Permits, Conservation, and Education Division). Representatives of the 
Marine Mammal Commission have also attended EOG meetings as observers. 
The EOG for SURTASS LFA sonar met twice in 2014 to review and further 
discuss the research recommendations put forth by the SAG, the 
feasibility of implementing any of the research efforts, and existing 
budgetary constraints. In addition to the research and monitoring 
efforts recommended by the SAG, additional promising suggestions for 
research/monitoring were recommended for consideration by the EOG. The 
EOG is considering which research/monitoring efforts are the most 
efficacious, given existing budgetary constraints, and will provide the 
Navy with a ranked list of research/monitoring recommendations. The EOG 
also determined that a study should be conducted to determine the 
extent of the overlap between potential LFA sonar operations and the 
distributional range of harbor porpoises; the Navy is in the process of 
finalizing this study. Following completion of all EOG consideration 
and evaluation, the Navy will prepare a research action plan for 
submittal to the NMFS Office of Protected Resources outlining the way 
forward (DoN, 2015). The Navy is committed to completing its assessment 
of the validity, need, and recommendations for field and/or laboratory 
research on the potential effects of SURTASS LFA sonar on beaked whales 
and harbor porpoises.
Ambient Noise Data Monitoring
    Several efforts (federal and academic) are underway to develop a 
comprehensive ocean noise budget (i.e., an accounting of the relative 
contributions of various underwater sources to the ocean noise field) 
for the world's oceans that include both anthropogenic and natural 
sources of noise. Ocean noise distributions and noise budgets are used 
in marine mammal masking studies, habitat characterization, and marine 
animal impact analyses.
    The Navy will collect ambient noise data when the SURTASS passive 
towed horizontal line array is deployed. However, because the collected 
ambient noise data may also contain sensitive acoustic information, the 
Navy classifies the data, and thus does not make these data publicly 
available. The Navy is exploring the feasibility of declassifying and 
archiving portions of the ambient noise data for incorporation into 
appropriate ocean noise budget efforts after all related security 
concerns have been resolved.
Research
    The Navy sponsors significant research and monitoring projects for 
marine living resources to study the potential effects of its 
activities on marine mammals. N2/N6 provides a representative to the 
Navy's Living Marine Resources advisory board to provide input to 
future research projects that may address SURTASS LFA sonar needs. In 
Fiscal Year 2014, the Navy reported that it spent $29.6 million (M) on 
marine mammal research and conservation during that year. This ongoing 
marine mammal research relates to hearing and hearing sensitivity, 
auditory effects, marine mammal monitoring and detection, noise 
impacts, behavioral responses, diving physiology and physiological 
stress, and distribution. The Navy sponsors a significant portion of 
U.S. research on the effects of human-generated underwater sound on 
marine mammals and approximately 50 percent of such research conducted 
worldwide. These research projects may not be specifically related to 
SURTASS LFA sonar activities; however, they are crucial to the overall 
knowledge base on marine mammals and the potential effects from 
underwater anthropogenic noise. The Navy also sponsors research to 
determine marine mammal abundances and densities for all Navy ranges 
and other operational areas. The Navy notes that research and 
evaluation is being carried out on various monitoring and mitigation 
methods, including passive acoustic monitoring, and the results from 
this research could be applicable to SURTASS LFA sonar passive acoustic 
monitoring. The Navy has also sponsored several workshops to evaluate 
the current state of knowledge and potential for future acoustic 
monitoring of marine mammals. The workshops bring together underwater 
acoustic subject matter experts and marine biologists from the Navy and 
other research organizations to present data and information on current 
acoustic monitoring research efforts, and to evaluate the potential for 
incorporating similar technology and methods on Navy instrumented 
ranges.
Adaptive Management
    Our understanding about marine mammals and the potential effects of 
SURTASS LFA sonar on marine mammals is continually evolving. Reflecting 
this, the proposed rule again includes an adaptive management framework 
that is supported by the Navy's 2016 SEIS/SOEIS. This allows the 
agencies to consider new/revised peer-reviewed and published scientific 
data and information from qualified and recognized sources within 
academia, industry, and government/non-government organizations to 
determine (with input regarding practicability) whether SURTASS LFA 
sonar mitigation, monitoring, or reporting measures should be modified 
(including additions or deletions) and to make such modification if new 
scientific data indicate that they would be appropriate. Modifications 
that are substantial would be made only after a 30-day period of public 
review and comment. Substantial modifications include a change in 
mission areas or new information that results in significant changes to 
mitigation. The framework also allows for updates to marine mammal 
stock estimates and newly classified species or stocks to be included 
in annual LOA applications, which, in turn, provides for the use of the 
best available scientific data for predictive models, including the 
Acoustic Integration Model (copyright) (AIM).
    As discussed in the Mitigation section above, NMFS and Navy have 
refined the adaptive management process for this rule compared to 
previous rulemakings. New information will still be considered

[[Page 19517]]

annually, but only in the context of the area in which SURTASS LFA 
assets will operate in that year. This approach allows a more focused 
and productive use of resources by evaluating only areas where SURTASS 
LFA sonar will be operating.
Proposed Reporting
    In order to issue an ITA for an activity, section 101(a)(5)(A) of 
the MMPA states that NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking.'' Effective reporting is 
critical both to compliance as well as ensuring that the most value is 
obtained from the required monitoring. There are several different 
reporting requirements in these proposed regulations:
General Notification of Injured or Dead Marine Mammals
    The Navy will systematically observe SURTASS LFA sonar activities 
for injured or disabled marine mammals. In addition, the Navy will 
monitor the principal marine mammal stranding networks and other media 
to correlate analysis of any whale mass strandings that could 
potentially be associated with SURTASS LFA sonar activities.
    Navy personnel will ensure that NMFS is notified immediately or as 
soon as clearance procedures allow if an injured, stranded, or dead 
marine mammal is found during or shortly after, and in the vicinity of, 
any SURTASS LFA sonar activities. The Navy will provide NMFS with 
species or description of the animal(s), the condition of the animal(s) 
(including carcass condition if the animal is dead), location, time of 
first discovery, observed behaviors (if alive), and photo or video (if 
available).
    In the event that an injured, stranded, or dead marine mammal is 
found by the Navy SURTASS LFA sonar vessel crew during transit, or that 
is not in the vicinity of, or found during or shortly after SURTASS LFA 
sonar activities, the Navy will report the same information as listed 
above as soon as operationally feasible and clearance procedures allow.
General Notification of a Ship Strike
    Because SURTASS LFA vessels move slowly, it is not likely these 
vessels would strike a marine mammal. In the event of a ship strike by 
the SURTASS LFA vessel, at any time or place, the Navy shall do the 
following:
     Immediately report to NMFS the species identification (if 
known), location (lat/long) of the animal (or the strike if the animal 
has disappeared), and whether the animal is alive or dead (or unknown);
     Report to NMFS as soon as operationally feasible the size 
and length of the animal, an estimate of the injury status (e.g., dead, 
injured but alive, injured and moving, unknown, etc.), vessel class/
type and operational status;
     Report to NMFS the vessel length, speed, and heading as 
soon as feasible; and
     Provide NMFS a photo or video, if equipment is available.
Quarterly Mitigation Monitoring Report
    On a quarterly basis, the Navy would provide NMFS with classified 
and unclassified reports that include all active-mode missions for each 
SURTASS LFA sonar vessel. The Navy would provide the quarterly mission 
reports no later than 45 days following the end of each quarter, 
beginning on the effective date of the annual LOA. Specifically, the 
classified reports will include dates/times of exercises, location of 
vessel, mission operational area, location of the mitigation zone in 
relation to the LFA sonar array, marine mammal observations, and 
records of any delays or suspensions of activities. Marine mammal 
observations would include animal type and/or species, number of 
animals sighted by species, date and time of observations, type of 
detection (visual, passive acoustic, HF/M3 sonar), the animal's bearing 
and range from vessel, behavior, and remarks/narrative (as necessary). 
The quarterly reports would include the Navy's analysis of take by 
Level A and/or Level B harassment, estimates of the percentage of 
marine mammal stocks affected (both for the quarter and cumulatively 
(to date) for the year covered by the LOA) by SURTASS LFA sonar 
activities. The Navy's estimates of the percentage of marine mammal 
stocks and number of individual marine mammals affected by exposure to 
SURTASS LFA sonar transmissions would be derived using acoustic impact 
modeling based on operating locations, season of missions, system 
characteristics, oceanographic environmental conditions, and marine 
mammal demographics. In the event that no SURTASS LFA missions are 
completed during a quarter, the Navy will provide NMFS with a report of 
negative activity for each SURTASS LFA sonar vessel.
Annual Report
    The annual report, which is due no later than 60 days after the 
expiration date of the annual LOAs, would provide NMFS with an 
unclassified summary of the year's quarterly reports including 
estimations of total percentages of each marine mammal stock affected 
by all SURTASS LFA sonar transmissions during the annual period using 
predictive modeling based on operating locations, dates/times of 
operations, system characteristics, oceanographic environmental 
conditions, and animal demographics.
    Additionally, the annual report would include: (1) Analysis of the 
effectiveness of the mitigation measures with recommendations for 
improvements where applicable; (2) assessment of any long-term effects 
from SURTASS LFA sonar activities; and (3) any discernible or estimated 
cumulative impacts from SURTASS LFA sonar activities.
Comprehensive Report
    NMFS proposes to require the Navy to provide NMFS and the public 
with a final comprehensive report analyzing the impacts of SURTASS LFA 
sonar on marine mammal species and stocks. This report would include an 
in-depth analysis of all monitoring and Navy-funded research pertinent 
to SURTASS LFA sonar activities conducted during the 5-year period of 
these regulations, a scientific assessment of cumulative impacts on 
marine mammal stocks, and an analysis on the advancement of alternative 
(passive) technologies as a replacement for LFA sonar. This report 
would be a key document for NMFS' review and assessment of impacts for 
any future rulemaking.
    The Navy shall respond to NMFS comments and requests for additional 
information or clarification on the quarterly, annual or comprehensive 
reports. These reports will be considered final after the Navy has 
adequately addressed NMFS' comments or provided the requested 
information, or three months after the submittal of the draft if NMFS 
does not comment within the three-month time period. NMFS will post the 
annual and comprehensive reports on the internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
Estimated Take of Marine Mammals
    This section includes an estimate of the number of incidental takes 
proposed for authorization pursuant to this rulemaking, which will 
inform NMFS' consideration of the negligible impact determination.
    Harassment is the primary means 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

[[Page 19518]]

to disturb a marine mammal or marine mammal stock in the wild by 
causing disruption of natural behavior patterns, including but not 
limited to, migration, surfacing, nursing, breeding, feeding, or 
sheltering, to a point where such behavioral patterns are abandoned or 
significantly altered (Level B Harassment). As described previously in 
the Potential Effects of the Specified Activity on Marine Mammals and 
their Habitat section, Level B Harassment is expected to occur and is 
proposed to be authorized as a maximum of 12 percent takes by Level B 
harassment per stock annually, and the Navy will use the 12 percent 
limit to guide its mission planning and annual LOA applications. 
Numbers and percentages of marine mammals and marine mammal stocks will 
be provided by the Navy in their annual application for LOAs, based on 
the mission areas for which the Navy anticipated SURTASS LFA sonar 
activities for that year.
    Based on the nature of the activities and the anticipated 
effectiveness of the mitigation measures, take by Level A Harassment is 
neither anticipated nor proposed to be authorized. The Navy's acoustic 
impact analysis for marine mammals represents an evolution that builds 
upon the analysis, methodology, and impact criteria documented in 
previous SURTASS LFA sonar NEPA efforts (DoN, 2001; 2007; 2012; 2015), 
and includes updates of the most current acoustic impact criteria and 
methodology to assess acoustic impacts (NMFS, 2016). A detailed 
discussion of the acoustic impact analysis is provided in Appendix B of 
the Navy's DSEIS/SOEIS, but is summarized here. Using AIM, the Navy 
modeled 26 representative mission areas in the Pacific, Atlantic, and 
Indian Oceans, as well as the Mediterranean Sea, representing the 
acoustic regimes and marine mammal species that may be encountered 
worldwide during SURTASS LFA sonar activities. To estimate real-world 
exposure estimates, the Navy used AIM to take the ship movement and 
speed, as well as LFA sonar transmissions, into account, and to 
simulate the modeled marine mammal species by creating animats 
programmed with behavioral values representative of the species, using 
density estimates for modeled species in each of the representative 
mission areas.
Density Estimates
    To derive density estimates, direct estimates from line-transect 
surveys that occurred in or near each of the 26 mission areas were 
utilized first (e.g., Barlow, 2006). However, density estimates were 
not always available for each species at all sites. When density 
estimates were not available from a survey in the operational area, 
density estimates from a region with similar oceanographic 
characteristics were extrapolated to the operational area. Densities 
for some mission areas/model sites were also derived from the Navy's 
Marine Species Density Database (DoN, 2016). Last, density estimates 
are usually not available for rare marine mammal species or for those 
that have been newly defined (e.g., Deraniyagala's beaked whale). For 
such species, a low density estimate of 0.0001 animals per square 
kilometer (animals/km\2\) was used in the risk analysis to reflect the 
low probability of occurrence in a specific mission area. Further, 
density estimates are sometimes pooled for species of the same genus if 
sufficient data are not available to compute a density for individual 
species or the species are difficult to distinguish at sea. This is 
often the case for pilot whales and beaked whales, as well as the pygmy 
and dwarf sperm whales. Density estimates are available to these 
species groups rather than the individual species. Density information 
is provided in Tables 3-28 above, and is also available in the Navy's 
application (Table 3-2, Pages 3-9 through 3-36).
Estimates of Potential Marine Mammal Exposure
    The process of estimating the marine mammal takes that may result 
from the proposed operation of SURTASS LFA sonar begins with the 
pertinent Navy commands proposing mission areas in which SURTASS LFA 
sonar may be operated. The Navy performs standard acoustic modeling and 
impact analyses, taking into account spatial, temporal, and/or 
operational parameters to determine the potential for PTS, TTS, or 
behavioral responses for each individual marine mammal. Then, the Navy 
applies standard mitigation measures (180-dB rms shutdown criteria) to 
the analysis to calculate take estimates for Level A harassment of 
marine mammal stocks in the proposed mission area. Based on these 
estimates, the Navy determines that the proposed missions meet the 
conditions of the MMPA incidental take regulation and LOAs, as issued 
(i.e., 12 percent Level B harassment limit per stock), for SURTASS LFA 
sonar. On a quarterly basis, the duration of actual sonar transmissions 
is recorded and compared to the predicted missions, as well as summed 
across the annual LOA period, to ensure that no more than 12% of any 
stock has been taken by Level B incidental harassment.
    The Navy assesses the potential impacts on marine mammals by 
predicting the sound field that a given marine mammal species could be 
exposed to over time in a potential mission area. This is a multi-part 
process involving: (1) The ability to measure or estimate an animal's 
location in space and time; (2) the ability to measure or estimate the 
three-dimensional sound field at these times and locations; (3) the 
integration of these two data sets into the acoustic impact model to 
estimate the total acoustic exposure for each animal in the modeled 
population; and (4) the conversion of the resultant cumulative 
exposures for a modeled population into an estimate of the risk of a 
disruption of natural behavioral patterns or TTS (i.e., a take estimate 
for Level B harassment) or of potential injury (i.e., Level A 
harassment).
    The Navy estimated the three-dimensional sound field using its 
standard parabolic equation (PE) transmission loss model. The results 
of this model are the primary input to the AIM, which the Navy used to 
estimate marine mammal sound exposures. AIM integrates simulated 
movements (including dive patterns) of marine mammals, a schedule of 
SURTASS LFA sonar transmissions, and the predicted sound field for each 
transmission to estimate acoustic exposure during a hypothetical 
SURTASS LFA sonar operation in each proposed mission area seasonally. A 
description of the PE and AIM models, including AIM input parameters 
for animal movement, diving behavior, and marine mammal distribution, 
abundance, and density are all described in detail in the Navy's 
application and in the Navy's DSEIS/SOEIS (see Appendix B for detailed 
information on the Marine Mammal Impact Analysis). NMFS has reviewed 
this information and has accepted the Navy modeling procedure and 
results.
    The acoustic impact analysis for this effort represents an 
evolution that builds upon the analysis, methodology, and impact 
criteria documented in previous SURTASS LFA sonar efforts summarized 
below (DoN, 2001; 2007; and 2012), but incorporates the most current 
acoustic impact criteria and methodology to assess the potential for 
auditory impacts and the best available data on behavioral responses of 
marine mammals to SURTASS LFA sonar. In addition, the Navy continuously 
updates the analysis with new marine mammal biological data (behavior, 
distribution, abundance and density) whenever new information becomes 
available.

[[Page 19519]]

    Because it is infeasible to model all potential LFA sonar operating 
areas worldwide, the Navy's application presents 26 modeled sites as 
examples to provide estimates of potential mission areas based on the 
current political climate. The Navy analyzed these 26 mission areas 
using the most up-to-date marine mammal abundance, density, and 
behavioral information available. These sites represent areas where 
SURTASS LFA sonar activities could potentially occur based on today's 
political climate. Table 6-2 of the Navy's application (pages 6-14 
through 6-34) provides the Navy's estimates of the percentage of marine 
mammal stocks potentially affected by SURTASS LFA sonar activities 
based on reasonable and realistic estimates of the potential effects to 
marine mammal stocks specific to the potential mission areas. These 
data are examples of areas where the Navy could request LOAs under the 
5-year rule because they are in areas of potential strategic importance 
and/or areas of possible naval fleet exercises. The percentage of 
marine mammal stocks that may experience TTS or behavioral changes from 
LFA sonar exposures was calculated for one season in each of the 26 
representative mission areas. The noise exposure scenario was also for 
a 24-hour period with LFA sonar transmitting 60-second signals every 
ten minutes for the entire period. Based on historical mission data, it 
is unlikely that such a scenario would occur, but is a conservative 
method for estimating potential impacts. As stated previously, this 
proposed rule calculates percentages of marine mammal species or stocks 
and does not specify the number of marine mammals that may be taken in 
the proposed locations because these are determined annually through 
various inputs such as mission location, mission duration, and season 
of operation and are included in the application for LOAs due to the 
fact that the Navy cannot know where they will need to operate each 
year over the five-year effective period of the proposed rule. For the 
annual application for an LOA, the Navy identifies the mission areas 
and proposes to present both the estimated percentage of a stock 
incidentally harassed as well as the estimated number of animals by 
species or stock that may be potentially harassed by SURTASS LFA sonar 
in each of the proposed mission areas for that annual period.
    With the implementation of the three-part monitoring programs 
(visual, passive acoustic, and HF/M3 monitoring), NMFS and the Navy do 
not expect that marine mammals would be injured by SURTASS LFA sonar 
because a marine mammal should be detected and active transmissions 
suspended or delayed. The probability of detection of a marine mammal 
by the HF/M3 system within the LFA sonar mitigation zone approaches 100 
percent based on multiple pings (see the 2001 FOEIS/EIS, Subchapters 
2.3.2.2 and 4.2.7.1 for the HF/M3 sonar testing results). 
Quantitatively, modelling output shows zero takes by Level A harassment 
for all marine mammal stocks in all representative mission areas with 
mitigation applied. As noted above, all hearing groups of marine 
mammals would need to be within 22 ft (7 m) for an entire LFA 
transmission (60 seconds), and a LF cetacean would need to be within 
135 ft (41 m) for an entire LFA transmission to potentially experience 
PTS. This is unlikely to occur, especially given the mitigation 
measures in place and their proven effectiveness at detecting marine 
mammals well outside of this range so that shut down measures would be 
implemented well before marine mammals would be within these ranges. 
Again, NMFS notes that over the course of the previous three 
rulemakings, there have been no reported or known incidents of Level A 
harassment of any marine mammal. Therefore, NMFS will not authorize any 
Level A takes for any marine mammal species or stocks over the course 
of the 5-year regulations. To potentially experience TTS, marine 
mammals would need to be at farther distances, but still within the 
approximately 2-km shutdown distance. The distances to the TTS 
thresholds are less than 50 ft (15 m) for MF and HF cetaceans and 
otariids, 216 ft (66 m) for phocids, and 1,354 ft (413 m) for LF 
cetaceans, if an animal were to remain at those distances for an entire 
LFA sonar signal (60 sec). While it is likely that mitigation measures 
would also avoid TTS, some small subset of the animals exposed above 
the Level B harassment threshold may also experience TTS. Any TTS 
incurred would likely be of a low level and of short duration because 
we do not expect animals to be exposed for long durations close to the 
source.
    As with the previous rules, the Navy will limit operation of 
SURTASS LFA sonar to ensure no marine mammal stock will be subject to 
more than 12 percent of the individuals of any stock taken by Level B 
harassment annually, during the five-year regulations. This annual per-
stock cap applies regardless of the number of LFA vessels operating. 
The Navy will use the 12 percent cap to guide its mission planning and 
annual LOA applications.
    As discussed, the Navy uses a behavioral response function to 
estimate the number of behavioral responses that would qualify as Level 
B behavioral harassment under the MMPA. As the statutory definition is 
currently applied, a wide range of behavioral reactions may qualify as 
Level B harassment under the MMPA, including but not limited to 
avoidance of the sound source, temporary changes in vocalizations or 
dive patterns, temporary avoidance of an area, or temporary disruption 
of feeding, migrating, or reproductive behaviors. The estimates 
calculated using the behavioral response function do not differentiate 
between the different types of potential behavioral reactions. Nor do 
the estimates provide information regarding the potential fitness or 
other biological consequences of the reactions on the affected 
individuals.
    NMFS notes that legislative history suggests that Congress intended 
that Level B harassment be limited to behavioral disturbances that have 
``demographic consequences to reproduction or survivability of the 
species.'' H.R. Conf. Rep. 108-354 (2003), 108th Cong., 1st Sess., 
reprinted in 2004 U.S.C.C.A.N. 1407, 1447. However, no methodology 
currently exists that would allow the Navy to estimate each type of 
potential behavioral response, predict any long-term consequences for 
the affected mammals, and then limit its take request to only the most 
severe responses that could have demographic consequences to 
reproduction or survivability. Therefore, as described above, the 
Navy's take estimates capture a wider range of less significant 
responses. NMFS does not assume that each instance of Level B 
harassment modeled by the Navy has, or is likely to have, an adverse 
population-level impact. Rather, NMFS considers the available 
scientific evidence to determine the likely nature of the modeled 
behavioral responses and the potential fitness consequences for 
affected individuals in its negligible impact evaluation.
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

[[Page 19520]]

adverse effects on annual rates of recruitment or survival (i.e., 
population-level effects). An estimate of the number of takes alone is 
not enough information on which to base an impact determination. In 
addition to considering the numbers of marine mammals that might be 
taken through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity and duration), the 
context of any response (e.g., critical reproductive time or location, 
migration, etc.), as well as effects on habitat, the status of the 
affected stocks, and the likely effectiveness of the mitigation. 
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 these analyses 
via their impacts on the environmental baseline (e.g., as reflected in 
the regulatory status of the species, population size, and growth rate 
where known, ongoing sources of human-caused mortality, or ambient 
noise levels).
    To avoid repetition, the discussion of our analyses applies to all 
the stocks listed in Tables 3 through 28, given that the anticipated 
effects of this activity on these different marine mammal stocks are 
expected to be similar, given the operational parameters of the 
activity. While there are differences in the hearing sensitivity of 
different groups, these differences have been factored into the 
analysis for auditory impairment. However, the nature of their 
behavioral responses is expected to be similar for SURTASS LFA sonar, 
especially given the context of their short duration open ocean 
exposures. Additionally, because of the comparatively small percentage 
of any population expected to be taken, combined with the operational 
avoidance of areas that are known to be important for specific 
biologically important reasons and the anticipated low-level effects, 
there is no need to differentially evaluate species based on varying 
status.
    The Navy has described its specified activities based on best 
estimates of the number of hours that the Navy will conduct SURTASS LFA 
activities. The exact number of transmission hours may vary from year 
to year, but will not exceed the annual total of 225 transmission hours 
per vessel per year as indicated in Table 1. This has been reduced from 
previous SURTASS LFA sonar rulemakings, which evaluated and authorized 
432 transmission hours per vessel per year. We note that this reduction 
in transmission hours represents a 41% reduction in sonar hours per 
ship during this next rulemaking period, which corresponds to less 
exposure and lessened takes compared to previous rules.
    As mentioned previously, NMFS estimates that 104 species of marine 
mammals could be taken by Level B harassment over the course of the 
five-year period. For reasons stated previously in this document, no 
mortalities are anticipated to occur as a result of the Navy's proposed 
SURTASS LFA sonar activities, and none are proposed to be authorized by 
NMFS. The Navy has operated SURTASS LFA sonar under NMFS regulations 
for the last fourteen years without any reports of serious injury or 
death. The evidence to date, including recent scientific reports and 
annual monitoring reports, and fourteen years of experience conducting 
SURTASS LFA activities further supports the conclusion that the 
potential for injury, and particularly serious injury, to occur is 
minimal.
    Taking the above into account, considering the sections discussed 
further, and dependent upon the implementation of the proposed 
mitigation measures, NMFS has preliminarily determined that use of 
SURTASS LFA sonar during activities will have a negligible impact on 
the marine mammal species and stocks present in operational areas in 
the Pacific, Atlantic, and Indian Oceans and the Mediterranean Sea, as 
listed in Tables 3-28 above.
    There is no empirical evidence of strandings of marine mammals 
associated spatially or temporally with the employment of SURTASS LFA 
sonar. Moreover, the sonar system acoustic characteristics differ 
between LFA sonar and MF sonars that have been associated with 
strandings: LFA sonars use frequencies from 100 to 500 Hz, with 
relatively long signals (pulses) on the order of 60 sec; while MF 
sonars use frequencies greater than 1,000 Hz, with relatively short 
signals on the order of 1 sec. NMFS has provided a summary of common 
features shared by the stranding events in Greece (1996), Bahamas 
(2000), Madeira (2000), Canary Islands (2002), Hanalei Bay (2004), and 
Spain (2006) earlier in this document. These included operation of MF 
sonar, deep water close to land (such as offshore canyons), presence of 
an acoustic waveguide (surface duct conditions), and periodic sequences 
of transient pulses (i.e., rapid onset and decay times) generated at 
depths less than 32.8 ft (10 m) by sound sources moving at speeds of 
2.6 m/s (5.1 knots) or more during sonar operations (D'Spain et al., 
2006). None of these features relate to SURTASS LFA sonar activities.
    Implementing a shutdown zone of approximately 2 km (1.2 mi; 1.1 
nmi, which is comprised of the LFA mitigation zone plus a 1-km buffer 
zone) around the LFA sonar array and vessel will ensure that no marine 
mammals are exposed to an SEL that would cause PTS or TTS. The proposed 
mitigation measures would allow the Navy to avoid exposing marine 
mammals to received levels of SURTASS LFA sonar or HF/M3 sonar sound 
that would result in injury (Level A harassment) and, as discussed in 
the Estimated Take of Marine Mammals section, most TTS (Level B 
harassment) would also be avoided due to mitigation measures, so that 
the majority of takes would be expected to be in the form of behavioral 
harassment (lower-level Level B harassment).
    As noted above, the context of exposures is important in evaluating 
the ultimate impacts of the take on the individuals. In the case of 
SURTASS LFA sonar, the approaching sound source would be moving through 
the open ocean at low speeds, so concerns of noise exposure are 
somewhat lessened in this context compared to situations where animals 
may not be as able to avoid strong or rapidly approaching sound 
sources. In addition, the duration of the take is important in the case 
of SURTASS LFA sonar, as the vessel continues to move and any 
interruption of behavior would be of relatively short duration.
    For SURTASS LFA sonar activities, the Navy provided information 
(Table 6-2 of the Navy's application) estimating percentages of marine 
mammal stocks that could potentially occur within the proposed 26 
worldwide mission areas. Based on our evaluation, take from the 
specified activities associated with the proposed SURTASS LFA sonar 
activities will most likely fall within the realm of short-term and 
temporary, or ephemeral, disruption of behavioral patterns (Level B 
harassment). NMFS bases this assessment on a number of factors 
considered together:
    (1) Geographic Restrictions--The OBIA and coastal standoff 
geographic restrictions on SURTASS LFA sonar activities are designed to 
minimize to the extent practicable the likelihood of disruption of 
marine mammals in areas where important behavior patterns such as 
migration, calving, breeding, feeding, or sheltering occur, or in areas 
with higher densities of marine mammals. As a result, the takes that 
occur are less likely to result in energetic effects or

[[Page 19521]]

disturbances that would reduce the reproductive success or 
survivorship.
    (2) Low Frequency Sonar Scientific Research Program (LFS SRP)--The 
Navy designed the three-phase LFS SRP study to assess the potential 
impacts of SURTASS LFA sonar on the behavior of low-frequency hearing 
specialists, those species believed to be at (potentially) greatest 
risk due to the presumed overlap in hearing of these species and the 
frequencies at which SURTASS LFA sonar is operated. This field research 
addressed three important behavioral contexts for baleen whales: (1) 
Blue and fin whales feeding in the southern California Bight, (2) gray 
whales migrating past the central California coast, and (3) humpback 
whales breeding off Hawaii. Taken together, the results from the three 
phases of the LFS SRP do not support the hypothesis that most baleen 
whales exposed to RLs near 140 dB re: 1 [mu]Pa would exhibit 
disturbance or avoidance behaviors. These experiments, which exposed 
baleen whales to received levels ranging from 120 to about 155 dB re: 1 
[mu]Pa, confirmed that some portion of the total number of whales 
exposed to LFA sonar responded behaviorally by changing their vocal 
activity, moving away from the source vessel, or both; but the 
responses were short-lived and animals returned to their normal 
activities within tens of minutes after initial exposure. These short-
term behavioral responses do not necessarily constitute significant 
changes in biologically important behaviors. In addition, these 
experiments illustrated that the context of an exposure scenario is 
important for determining the probability, magnitude, and duration of a 
response. This was shown by the fact that migrating gray whales 
responded to a sound source in the middle of their migration route but 
showed no response to the same sound source when it was located 
offshore, outside the migratory corridor, even when the source level 
was increased to maintain the same received levels within the migratory 
corridor. Although this study is nearly two decades old, the collected 
behavioral response data remain valid and highly relevant, particularly 
since the information has been bolstered by other, more recent studies 
as discussed in the Behavioral Response/Disturbance section above. 
Therefore, take estimates for SURTASS LFA sonar are likely very 
conservative (though we analyze them here nonetheless), and takes that 
do occur will be limited to lower Level B harassment takes.
    (3) Efficacy of the Navy's Three-Part Mitigation Monitoring 
Program--Review of Final Comprehensive and Annual Reports from August 
2002 through August 2016 (14 years) indicates that the Navy has 
completed 171 missions and has reported 27 visual sightings, 11 passive 
acoustic detections, and 206 HF/M3 active sonar detections of marine 
mammals. The HF/M3 active sonar system has proven to be the most 
effective of the mitigation monitoring measures to detect possible 
marine mammals in proximity to the transmitting LFA sonar array, and 
use of this system substantially increases the probability of detecting 
marine mammals within the mitigation zone (and beyond), providing a 
superior monitoring capability. Because the HF/M3 active sonar is able 
to monitor large and medium marine mammals out to an effective range of 
2 to 2.5 km (1.2 to 1.5 mi; 1.1 to 1.3 nmi) from the vessel, it is 
unlikely that the SURTASS LFA operations would expose marine mammals to 
an SPL greater than about 174 dB re: 1 [mu]Pa at 1 m. Past results of 
the HF/M3 sonar system tests provide confirmation that the system has a 
demonstrated probability of single-ping detection of 95 percent or 
greater for single marine mammals that are 10 m (32.8 ft) in length or 
larger, and a probability approaching 100 percent for multiple pings of 
any sized marine mammal. Lastly, as noted above, from the commencement 
of SURTASS LFA sonar use in 2002 through the present, neither operation 
of LFA sonar, nor operation of the T-AGOS vessels, has been associated 
with any mass or individual strandings of marine mammals. In addition, 
required monitoring reports indicate that there have been no apparent 
avoidance reactions observed, and no Level A harassment takes due to 
SURTASS LFA sonar since its use began in 2002 (see Results from Past 
Monitoring, above).
    In examining the results of the mitigation monitoring procedures 
over the previous 14 years of SURTASS LFA activities, NMFS has 
concluded that the mitigation and monitoring measures for triggering 
shutdowns of the LFA sonar system have been implemented properly and 
have successfully minimized the potential adverse effects of SURTASS 
LFA sonar to marine mammals in the mitigation and buffer zone around 
the vessel. This conclusion is further supported by documentation that 
no known mortality or injury to marine mammals has occurred over this 
period.
    For reasons discussed previously, NMFS anticipates that the effect 
of masking will be limited and the chances of an LFA sonar sound 
overlapping whale calls at levels that would interfere with their 
detection and recognition will be extremely low. Also as discussed 
previously, NMFS does not expect any short- or long-term effects to 
marine mammal food resources from SURTASS LFA sonar activities. It is 
unlikely that the activities of the four SURTASS LFA sonar vessels 
operating approximately 40 days maximum of LFA at any place in the 
action area over the course of a year would implicate all of the areas 
for a given species or stock in any year. It is anticipated that ample 
similar habitat areas are available for species/stocks in the event 
that portions of preferred areas are ensonified. Implementation of the 
LFA shutdown zone and additional 1-km buffer would ensure that most 
marine mammal takes are limited to lower-level Level B harassment. 
Further, in areas of known biological importance for functions such as 
feeding, reproduction, etc., effects are mitigated by OBIAs. As 
described previously, the Navy implements a 12% cap on affected 
species/stocks of marine mammals and, as indicated from previous 
monitoring reports, this level has generally never come close to being 
affected by SURTASS LFA sonar.
    In summary (from the discussion above this section), NMFS has made 
a preliminary finding that the total taking from SURTASS LFA sonar 
activities will have a negligible impact on the affected species or 
stocks based on following: (1) The historical demonstrated 
effectiveness of the Navy's three-part monitoring program in detecting 
marine mammals and triggering shutdowns, which make it unlikely that an 
animal will be exposed to sound levels associated with potential injury 
or TTS; (2) Geographic restrictions requiring the SURTASS LFA sonar 
sound field not exceed 180 dB within 22 km of any shoreline, including 
islands, or at a distance of one km from the perimeter of an OBIA; (3) 
The small number of SURTASS LFA sonar systems that would be operating 
world-wide (likely not in close proximity to one another); (4) The 
relatively low duty cycle, short mission periods and offshore nature of 
the SURTASS LFA sonar; (5) The fact that marine mammals in unspecified 
migration corridors and open ocean concentrations would be adequately 
protected from exposure to sound levels that would result in injury, 
TTS, and more severe levels of behavioral disruption by the three-part 
monitoring and mitigation protocols; and (6) Monitoring results from 
the previous fourteen years of SURTASS LFA sonar activities show that 
take numbers have been well below the 12 percent cap for Level B 
harassment for each stock, and there have been no Level A takes.

[[Page 19522]]

Impacts to marine mammals are anticipated to be predominantly in the 
form of lower-level Level B behavioral harassment, due to the brief 
duration and sporadic nature of the SURTASS LFA sonar activities. For 
example, certain species may have a behavioral reaction (such as 
increased swim speed, avoidance of the area, etc.) to the sound emitted 
during the proposed activities.
    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.
Subsistence Harvest of Marine Mammals
    Although the Navy will not operate SURTASS LFA sonar in the vast 
majority of Arctic waters, the Navy may potentially operate LFA sonar 
in the Gulf of Alaska or southward off the Aleutian Island chain, where 
subsistence uses of marine mammals under NMFS jurisdiction occur. Seven 
species of pinnipeds, one species of odontocetes (beluga whale), and 
one species of mysticetes (bowhead whale) are targeted by subsistence 
hunting in Alaska. The stocks of beluga whales that experience Alaska 
Native subsistence hunting are located in the Arctic waters and would 
not be impacted by SURTASS LFA sonar. The Western Arctic stock of 
bowhead whales experience subsistence hunting from Alaska, Canadian, 
and Russian Natives, but would not occur in the operational areas of 
SURTASS LFA sonar and would not be impacted by sonar transmissions. The 
distributions of bearded and ringed seals overlap with operational 
areas of SURTASS LFA sonar in the Sea of Okhotsk, but these are not 
stocks that experience subsistence hunting. The Alaska Native harvest 
of harbor seals from twelve stocks identified in Alaska occurs at haul-
out sites within the coastal standoff geographic restriction of SURTASS 
LFA sonar. The remaining four species of pinnipeds (northern fur seal, 
ribbon seal, spotted seal, and Steller sea lion) experience Native 
Alaska subsistence hunting and may be exposed to SURTASS LFA sonar 
transmissions. Pinnipeds are not low-frequency hearing specialists and 
the potential for impacts from SURTASS LFA sonar are limited to minimal 
risk for behavioral change.
    Should the Navy operate SURTASS LFA sonar in the Gulf of Alaska, 
sonar operation would adhere to the shutdown in the mitigation and 
buffer zones, as well as established geographic restrictions, which 
include the coastal standoff range and OBIAs (which dictates that the 
sound field produced by the sonar must be below 180 dB re: 1 [mu]Pa at 
1 m within 22 km (13. mi; 12 nmi) of any coastline or 1 km from the 
boundary of an OBIA during the time of its biological importance).
    Although there are peaks in harvest activity for both species, most 
subsistence hunting occurs in the winter from January to March when 
seals have restricted distributions on the ice front. While it is 
impossible to predict the future timing of the possible employment of 
SURTASS LFA sonar in the Gulf of Alaska, regardless of the time of year 
the sonar may be employed in the Gulf of Alaska, there should be no 
overlap in time or space with subsistence hunts due to the geographic 
restrictions on the sonar use (i.e., coastal standoff range and OBIA 
restrictions). These restrictions will prevent the Navy from generating 
a sound field that reaches the shallow coastal and inshore areas of the 
Gulf of Alaska where harvest of the two pinniped species occurs. The 
possible employment of SURTASS LFA sonar in the Gulf of Alaska will not 
cause abandonment of any harvest/hunting locations, will not displace 
any subsistence users, nor place physical barriers between marine 
mammals and the hunters. No mortalities of marine mammals have been 
associated with the employment of SURTASS LFA sonar and the Navy 
undertakes a suite of mitigation measures whenever SURTASS LFA sonar is 
actively transmitting. Therefore, NMFS has preliminarily determined 
that the possible future employment of SURTASS LFA sonar will not lead 
to unmitigable adverse impacts on the availability of marine mammal 
species or stocks for subsistence uses in the Gulf of Alaska or along 
the Aleutian Island chain.
    As part of the public review and comment period for the 2016 DSEIS/
SOEIS, letters requesting review were distributed by the Navy to 
solicit comment from Alaska Native groups on the potential use of 
SURTASS LFA sonar worldwide. To date, the Navy has not received 
comments on the DSEIS/SOEIS from Alaska Native groups, nor any requests 
from Alaskan tribes for government-to-government consultation pursuant 
to Executive Order 13175. The Navy will continue to keep the Alaskan 
tribes informed of the timeframes of any future SURTASS LFA sonar 
exercises planned for the area.
Endangered Species Act
    There are 20 marine mammal species under NMFS' jurisdiction that 
are listed as endangered or threatened under the ESA with confirmed or 
possible occurrence in potential world-wide mission areas for SURTASS 
LFA: The blue; fin; sei; humpback (Arabian Sea, Cape Verde Islands/
Northwest Africa, Central America, Mexico, and Western North Pacific 
distinct population segments (DPS)); bowhead; North Atlantic right; 
North Pacific right; southern right; Western North Pacific DPS of gray; 
sperm; Cook Inlet DPS of beluga; Main Hawaiian Islands Insular DPS of 
false killer; and Southern Resident DPS of killer whales, as well as 
the western DPS of the Steller sea lion; Mediterranean monk seal; 
Hawaiian monk seal; the Guadalupe fur seal; the Okhotsk ringed seal; 
the Okhotsk DPS of Pacific bearded seal; and the Southern DPS of 
spotted seal. In addition, NMFS has proposed to list the Gulf of Mexico 
Bryde's whale as an endangered species (81 FR 88639, December 8, 2016).
    On October 3, 2016, the Navy submitted a Biological Assessment to 
NMFS to initiate consultation under section 7 of the ESA for the 2017-
2022 SURTASS LFA sonar activities and NMFS' authorization for 
incidental take under section 101(a)(5)(A) of the MMPA. NMFS and Navy 
will conclude consultation with NMFS's Office of Protected Resources, 
Interagency Cooperation Division prior to making a determination on the 
issuance of the final rule and LOAs.
    The USFWS is responsible for regulating the take of the several 
marine mammal species including the southern sea otter, polar bear, 
walrus, West African manatee, Amazonian manatee, West Indian manatee, 
and dugong. The Navy has determined that none of these species occur in 
geographic areas that overlap with SURTASS LFA sonar activities and, 
therefore, that SURTASS LFA sonar activities will have no effect on the 
endangered or threatened species or the critical habitat of ESA-listed 
species under the jurisdiction of the USFWS. Thus, no consultation with 
the USFWS pursuant to Section 7 of the ESA will occur.
National Environmental Policy Act
    Pursuant to the National Environmental Policy Act (NEPA), the Navy 
has prepared a DSEIS/SOEIS for the specified activity. NMFS is acting 
as a cooperating agency in the development of the NEPA document.

[[Page 19523]]

NMFS plans to adopt the Navy's final SEIS/SOEIS for its action of 
issuing regulations and LOAs.
    The Navy published a Notice of Availability of a DSEIS/SOEIS for 
employment of SURTASS LFA sonar in the Federal Register on August 26, 
2016, which was available for public review and comment until October 
11, 2016. The public may still view the DSEIS/SOEIS at: https://www.surtass-lfa-eis.com.
    Prior to issuing the final rule and the first LOA for the proposed 
activities, NMFS will evaluate the comments received on the DSEIS/
SOEIS, comments received as a result of this proposed rulemaking, and 
the Navy's Final SEIS/SOEIS, and will issue a Record of Decision (ROD).
Classification
    This action does not contain any collection of information 
requirements for purposes of the Paperwork Reduction Act of 1980 (44 
U.S.C. 3501 et seq.).
    The Office of Management and Budget has determined that this 
proposed rule is not significant for purposes of Executive Order 12866.
    Pursuant to the Regulatory Flexibility Act (RFA), the Chief Counsel 
for Regulation of the Department of Commerce has certified to the Chief 
Counsel for Advocacy of the Small Business Administration that this 
proposed rule, if adopted, would not have a significant economic impact 
on a substantial number of small entities. The RFA requires a Federal 
agency to prepare an analysis of a rule's impact on small entities 
whenever the agency is required to publish a notice of proposed 
rulemaking. However, a Federal agency may certify, pursuant to 5 U.S.C. 
605 (b), that the action will not have a significant economic impact on 
a substantial number of small entities. The Navy is the sole entity 
that will be affected by this rulemaking and is not a small 
governmental jurisdiction, small organization, or small business, as 
defined by the RFA. Any requirements imposed by LOAs issued pursuant to 
these regulations, and any monitoring or reporting requirements imposed 
by these regulations, will be applicable only to the Navy.
    NMFS does not expect the issuance of these regulations or the 
associated LOAs to result in any impacts to small entities pursuant to 
the RFA. Because this action, if adopted, would directly affect the 
Navy and not a small entity, NMFS concludes the action would not result 
in a significant economic impact on a substantial number of small 
entities.

List of Subjects in 50 CFR Part 218

    Exports, Fish, Imports, Indians, Labeling, Marine mammals, 
Penalties, Reporting and recordkeeping requirements, Seafood, 
Transportation.

    Dated: April 17, 2017.
Alan D. Risenhoover,
Acting Deputy Assistant Administrator for Regulatory Programs, National 
Marine Fisheries Service.

    For reasons set forth in the preamble, 50 CFR part 218 is proposed 
to be amended as follows:

PART 218--REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE 
MAMMALS

0
1. The authority citation for part 218 continues to read as follows:

    Authority: 16 U.S.C. 1361 et seq.

0
2. Under part 218, revise Subpart X to read as follows:
Subpart X--Taking and Importing of Marine Mammals; Navy Operations of 
Surveillance Towed Array Sensor System Low Frequency Active (SURTASS 
LFA) Sonar
Sec.
218.230 Specified activity, level of taking, and species.
218.231 Effective dates.
218.232 Permissible methods of taking.
218.233 Prohibitions.
218.234 Mitigation.
218.235 Requirements for monitoring.
218.236 Requirements for reporting.
218.237 Applications for letters of authorization.
218.238 Letters of authorization.
218.239 Renewal of letters of authorization.
218.240 Modifications to letters of authorization.
218.241 Adaptive management.

Subpart X--Taking and Importing of Marine Mammals; Navy Operations 
of Surveillance Towed Array Sensor System Low Frequency Active 
(SURTASS LFA) Sonar


Sec.  218.230  Specified activity, level of taking, and species.

    Regulations in this subpart apply only to the incidental taking of 
those marine mammal species specified in paragraph (b) of this section 
by the U.S. Navy, Department of Defense, while engaged in the operation 
of no more than four SURTASS LFA sonar systems conducting active sonar 
activities in areas specified in paragraph (a) of this section. The 
authorized activities, as specified in a Letter of Authorization issued 
under Sec. Sec.  216.106 and 218.238 of this chapter, include the 
transmission of low frequency sounds from the SURTASS LFA sonar system 
and the transmission of high frequency sounds from the mitigation sonar 
described in Sec.  218.234 during routine training, testing, and 
military operations.
    (a) The incidental take, by Level B harassment, of marine mammals 
from the activity identified in this section may be authorized in 
certain areas of the Pacific, Atlantic, and Indian Oceans and the 
Mediterranean Sea, as specified in a Letter of Authorization.
    (b) The incidental take of marine mammals from the activity 
identified in this section is limited to the following currently 
classified species and stocks, and may also cover stocks that represent 
further formal divisions of these species and stocks of marine mammals, 
provided that NMFS is able to confirm that the level of taking for 
those stocks and other factors will be consistent with the findings 
made for current stocks:
    (1) Mysticetes-blue whale (Balaenoptera musculus), pygmy blue whale 
(Balaenoptera musculus brevicauda), bowhead whale (Balaena mysticetus), 
Bryde's whale (Balaenoptera edeni), fin whale (Balaenoptera physalus), 
gray whale (Eschrichtius robustus), humpback whale (Megaptera 
novaeangliae), common minke whale (Balaenoptera acutorostrata), 
Antarctic minke whale (Balaenoptera bonaerensis), North Atlantic right 
whale (Eubalaena glacialis), North Pacific right whale (Eubalena 
japonica), pygmy right whale (Capera marginata), sei whale 
(Balaenoptera borealis), southern right whale (Eubalaena australis), 
Omura's whale (Balaenoptera omurai).
    (2) Odontocetes-Andrew's beaked whale (Mesoplodon bowdoini), 
Arnoux's beaked whale (Berardius arnuxii), Atlantic spotted dolphin 
(Stenella frontalis), Atlantic white-sided dolphin (Lagenorhynchus 
acutus), Baird's beaked whale (Berardius bairdii), Beluga whale 
(Dephinapterus leucas), Blainville's beaked whale (Mesoplodon 
densirostris), Chilean dolphin (Cephalorhynchus eutropia), Clymene 
dolphin (Stenella clymene), Commerson's dolphin (Cephalorhynchus 
commersonii), common bottlenose dolphin (Tursiops truncatus), Cuvier's 
beaked whale (Ziphius cavirostris), Dall's porpoise (Phocoenoides 
dalli), Deraniyagala's beaked whale (Mesoplodon hotaula), Dusky dolphin 
(Lagenorhynchus obscurus), dwarf sperm and pygmy sperm whales (Kogia 
simus and K. breviceps), false killer whale (Pseudorca crassidens), 
Fraser's dolphin (Lagenodelphis hosei), Gervais' beaked whale 
(Mesoplodon europaeus), ginkgo-toothed beaked whale (Mesoplodon 
ginkgodens), Gray's beaked whale (Mesoplodon grayi), Heaviside's 
dolphin (Cephalorhynchus heavisidii), Hector's

[[Page 19524]]

beaked whale (Mesoplodon hectori), Hector's dolphin (Cephalorhynchus 
hectori); Hourglass dolphin (Lagenorhynchus cruciger), Hubbs' beaked 
whale (Mesoplodon carhubbsi), harbor porpoise (Phocoena phocoena); 
Indo-pacific common dolphin (Delphinus delphis tropicalis), Indo-
Pacific bottlenose dolphin (Tursiops aduncus), killer whale (Orca 
orcinus), long-beaked common dolphin (Delphinus capensis), long-finned 
pilot whale (Globicephala melas), Longman's beaked whale (Indopacetus 
pacificus), melon-headed whale (Peponocephala electra), northern 
bottlenose whale (Hyperodon ampullatus), northern right whale dolphin 
(Lissodelphis borealis), Pacific white-sided dolphin (Lagenorhynchus 
obliquidens), pantropical spotted dolphin (Stenella attenuata), Peale's 
dolphin (Lagenorhynchus australis), Perrin's beaked whale (Mesoplodon 
perrini), pygmy beaked whale (Mesoplodon peruvianus), pygmy killer 
whale (Feresa attenuata), Risso's dolphin (Grampus griseus), rough-
toothed dolphin (Steno bredanensis), Shepherd's beaked whale 
(Tasmacetus sheperdii), short-beaked common dolphin (Delphinus 
delphis), short-finned pilot whale (Globicephala macrorhynchus), 
southern bottlenose whale (Hyperodon planifrons), southern right whale 
dolphin (Lissodelphis peronii), Sowerby's beaked whale (Mesoplodon 
bidens), spade-toothed beaked whale (Mesoplodon traversii), spectacled 
porpoise (Phocoena dioptrica), sperm whale (Physeter macrocephalus), 
spinner dolphin (Stenella longirostris), Stejneger's beaked whale 
(Mesoplodon stejnegeri), strap-toothed beaked whale (Mesoplodon 
layardii), striped dolphin (Stenella coeruleoalba), True's beaked whale 
(Mesoplodon mirus), white-beaked dolphin (Lagenorhynchus albirostris),
    (3) Pinnipeds-Australian fur seal (Arctocephalus pusillus 
doriferus), Australian sea lion (Neophoca cinerea), California sea lion 
(Zalophus californianus), Eastern (Loughlin's) Steller sea lion 
(Eumetopias jubatus monteriensis), Galapagos fur seal (Arctocephalus 
galapagoensis), Galapagos sea lion (Zalophus wollebaeki), Guadalupe fur 
seal (Arctocephalus townsendi), Juan Fernandez fur seal (Arctocephalus 
philippi philippi), New Zealand fur seal (Arctocephalus forsteri), New 
Zealand sea lion (Phocarctos hookeri), northern fur seal (Callorhinus 
ursinus), South African or Cape fur seals (Arctocephalus pusillus 
pusillus), South American fur seal (Arctocephalus australis), South 
American sea lion (Otaria flavescens), subantarctic fur seal 
(Arctocephalus tropicalis), Western Steller sea lion (Eumetopiaas 
jubatus jubatus), Atlantic gray seal (Halichoerus grypus atlantica), 
Atlantic ringed seal (Pusa hispida hispida), Atlantic and Pacific 
harbor seal (Phoca vitulina), harp seal (Pagophilus groenlandicus), 
Hawaiian monk seal (Monachus schauinslandi), hooded seal (Cystophora 
cristata), Mediterranean monk seal (Monachus monachus), northern 
elephant seal (Mirounga angustirostris), Okhotsk ringed seal (Pusa 
hispida ochotensis), Pacific bearded seal (Erignathus barbatus 
nauticus), ribbon seal (Phoca fasciata), southern elephant seal 
(Mirounga leonina), spotted seal (Phoca largha).


Sec.  218.231  Effective dates.

    Regulations are effective August 15, 2017, through August 14,


Sec.  218.232  Permissible methods of taking.

    (a) Under Letters of Authorization issued pursuant to Sec. Sec.  
216.106 and 218.238 of this chapter, the Holder of the Letter of 
Authorization may incidentally, but not intentionally, take marine 
mammals by Level B harassment within the areas described in (a), 
provided that the activity is in compliance with all terms, conditions, 
and requirements of this subpart and the appropriate Letter of 
Authorization.
    (b) The incidental take of marine mammals under the activities 
identified in Sec.  218.230 is limited to the species listed in Sec.  
218.230(b) by the method of take indicated in paragraph (b)(2) of this 
section.
    (1) The Navy must maintain a running calculation/estimation of 
takes of each species or stock over the effective period of this 
subpart.
    (2) Takes by Level B Harassment will not exceed 12 percent of any 
marine mammal stock listed in Sec.  218.230(b)(1) through (3) annually 
over the course of the five-year regulations. This annual per-stock cap 
of 12 percent applies regardless of the number of LFA vessels 
operating.


Sec.  218.233  Prohibitions.

    No person in connection with the activities described in Sec.  
218.230 may:
    (a) Take any marine mammal not specified in Sec.  218.230(b);
    (b) Take any marine mammal specified in Sec.  218.230 other than by 
incidental take as specified in Sec.  218.232(b)(2);
    (c) Take any marine mammal specified in Sec.  218.230 if NMFS makes 
a determination that such taking will result, or is resulting, in more 
than a negligible impact on the species or stocks of such marine 
mammal; or
    (d)(d) Violate, or fail to comply with, any of the terms, 
conditions, or requirements of this subpart or any Letter of 
Authorization issued under Sec.  216.106 and 218.238 of this chapter.


Sec.  218.234  Mitigation.

    When conducting activities identified in Sec.  218.230, the 
mitigation measures described in this section and in any Letter of 
Authorization issued under Sec.  216.106 and Sec.  218.238 must be 
implemented.
    (a) Personnel Training--Lookouts: (1) The Navy shall train the 
lookouts in the most effective means to ensure quick and effective 
communication within the command structure in order to facilitate 
implementation of protective measures if they spot marine mammals.
    (2) The Navy will hire one or more marine mammal biologist 
qualified in conducting at-sea marine mammal visual monitoring from 
surface vessels to train and qualify designated ship personnel to 
conduct at-sea visual monitoring. This training may be accomplished 
either in-person, or via video training.
    (b) General Operating Procedures: (1) Prior to SURTASS LFA sonar 
activities, the Navy will promulgate executive guidance for the 
administration, execution, and compliance with the environmental 
regulations under this subpart and Letters of Authorization.
    (2) The Holder of a Letter of Authorization will not transmit the 
SURTASS LFA sonar signal at a frequency greater than 500 Hz.
    (c) LFA Sonar Mitigation Zone and 1-km Buffer Zone; Suspension and 
Delay: (1) Prior to commencing and during SURTASS LFA sonar 
transmissions, the Holder of a Letter of Authorization will determine 
the propagation of LFA sonar signals in the ocean and the distance from 
the SURTASS LFA sonar source to the 180-decibel (dB) re: 1 [mu]Pa 
isopleth.
    (2) The Holder of a Letter of Authorization will establish an 180-
dB LFA mitigation zone around the surveillance vessel that is equal in 
size to the 180-dB re: 1 [mu]Pa isopleth (i.e., the volume subjected to 
sound pressure levels of 180 dB or greater) as well as a one-kilometer 
(1-km) buffer zone around the LFA mitigation zone.
    (3) If a marine mammal is detected, through monitoring required 
under Sec.  218.235, within or about to enter the LFA mitigation zone 
plus the 1-km buffer zone, the Holder of the Authorization will 
immediately delay or suspend SURTASS LFA sonar transmissions.

[[Page 19525]]

    (d) Resumption of SURTASS LFA sonar transmissions: (1) The Holder 
of a Letter of Authorization will not resume SURTASS LFA sonar 
transmissions earlier than 15 minutes after:
    (i) All marine mammals have left the area of the LFA mitigation and 
buffer zones; and
    (ii) There is no further detection of any marine mammal within the 
LFA mitigation and buffer zones as determined by the visual, passive, 
and high frequency monitoring described in Sec.  218.235.
    (2) [Reserved]
    (e) Ramp-up Procedures for the high-frequency marine mammal 
monitoring (HF/M3) sonar required under Sec.  218.235: (1) The Holder 
of a Letter of Authorization will ramp up the HF/M3 sonar power level 
beginning at a maximum source sound pressure level of 180 dB: re 1 
[mu]Pa at 1 meter in 10-dB increments to operating levels over a period 
of no less than five minutes:
    (i) At least 30 minutes prior to any SURTASS LFA sonar 
transmissions;
    (ii) Prior to any SURTASS LFA sonar calibrations or testing that 
are not part of regular SURTASS LFA sonar transmissions described in 
Sec.  218.230; and
    (iii) Anytime after the HF/M3 source has been powered down for more 
than two minutes.
    (2) The Holder of a Letter of Authorization will not increase the 
HF/M3 sound pressure level once a marine mammal is detected; ramp-up 
may resume once marine mammals are no longer detected.
    (f) Geographic Restrictions on the SURTASS LFA Sonar Sound Field: 
(1) The Holder of a Letter of Authorization will not operate the 
SURTASS LFA sonar such that:
    (i) The SURTASS LFA sonar sound field exceeds 180 dB re: 1 [mu]Pa 
(rms) at a distance less than 12 nautical miles (nmi) (22 kilometers 
(km)) from any land, including offshore islands;
    (ii) The SURTASS LFA sonar sound field exceeds 180 dB re: 1 [mu]Pa 
(rms) at a distance less than 1 km (0.5 nm) seaward of the outer 
perimeter of any Offshore Biologically Important Area (OBIA) designated 
in Sec.  218.234(f)(2), or identified through the Adaptive Management 
process specified in Sec.  218.241, during the period specified. The 
boundaries and periods of such OBIAs will be kept on file in NMFS' 
Office of Protected Resources and on its Web site at https://www/
nmfs.noaa.gov/pr/permits/incidental/military.htm.
    (2) Offshore Biologically Important Areas (OBIAs) for marine 
mammals (with specified periods) for SURTASS LFA sonar activities 
include the following:

------------------------------------------------------------------------
        Name of area            Location of area    Months of importance
------------------------------------------------------------------------
Georges Bank................  Northwest Atlantic    Year-round.
                               Ocean.
Roseway Basin Right Whale     Northwest Atlantic    June through
 Conservation Area.            Ocean.                December, annually.
Great South Channel, U.S.     Northwest Atlantic    January 1 to
 Gulf of Maine, and            Ocean/Gulf of Maine.  November 14,
 Stellwagen Bank National                            annually.
 Marine Sanctuary (NMS).
Southeastern U.S. Right       Northwest Atlantic    November 15 to
 Whale Habitat.                Ocean.                January 15,
                                                     annually.
Gulf of Alaska..............  Gulf of Alaska......  March through
                                                     August, annually.
Navidad Bank................  Caribbean Sea/        December through
                               Northwest Atlantic    April, annually.
                               Ocean.
Coastal waters of Gabon,      Southeastern          June through
 Congo and Equatorial Guinea.  Atlantic Ocean.       October, annually.
Patagonian Shelf Break......  Southwestern          Year-round.
                               Atlantic Ocean.
Southern Right Whale          Southwestern          May through
 Seasonal Habitat.             Atlantic Ocean.       December, annually.
Central California..........  Northeastern Pacific  June through
                               Ocean.                November, annually.
Antarctic Convergence Zone..  Southern Ocean......  October through
                                                     March, annually.
Piltun and Chayvo offshore    Sea of Okhotsk......  June through
 feeding grounds.                                    November, annually.
Coastal waters off            Western Indian Ocean  July through
 Madagascar.                                         September, annually
                                                     for humpback whale
                                                     breeding and
                                                     November through
                                                     December, annually
                                                     for migrating blue
                                                     whales.
Madagascar Plateau,           Western Indian Ocean  November through
 Madagascar Ridge, and                               December, annually.
 Walters Shoal.
Ligurian-Corsican-Provencal   Northern              July to August,
 Basin and Western Pelagos     Mediterranean Sea.    annually.
 Sanctuary.
Penguin Bank, Hawaiian        North-Central         November through
 Islands Humpback Whale NMS.   Pacific Ocean.        April, annually.
Costa Rica Dome.............  Eastern Tropical      Year-round.
                               Pacific Ocean.
Great Barrier Reef Between..  Coral Sea/            May through
                               Southwestern          September,
                               Pacific Ocean.        annually.
Bonney Upwelling............  Southern Ocean......  December through
                                                     May, annually.
Northern Bay of Bengal and    Bay of Bengal/        Year-round.
 Head of Swatch-of-No-Ground   Northern Indian
 (SoNG).                       Ocean.
Olympic Coast NMS and         Northeastern Pacific  Olympic NMS:
 Prairie, Barkley Canyon,      Ocean.                December, January,
 and Nitnat Canyon.                                  March, and May
                                                     annually.
                                                    Prairie, Barkley
                                                     Canyon, and Nitnat
                                                     Canyon: June
                                                     through September
                                                     annually.
Abrolhos Bank...............  Southwest Atlantic    August through
                               Ocean.                November, annually.
Grand Manan North Atlantic    Bay of Fundy, Canada  June through
 Right Whale Critical                                December, annually.
 Habitat.
Eastern Gulf of Mexico......  Eastern Gulf of       Year-round.
                               Mexico.
Southern Chile Coastal        Gulf of Corcovado,    February to April,
 Waters.                       Southeast Pacific     annually.
                               Ocean; Southwestern
                               Chile.
Offshore Sri Lanka..........  North-Central Indian  December through
                               Ocean.                April, annually.
Camden Sound/Kimberly Region  Southeast Indian      June through
                               Ocean; northwestern   September,
                               Australia.            annually.
Perth Canyon................  Southeast Indian      January through May,
                               Ocean; southwestern   annually.
                               Australia.
------------------------------------------------------------------------


[[Page 19526]]

    (g) Operational Exception for the SURTASS LFA Sonar Sound Field. 
During military operations SURTASS LFA sonar transmissions may exceed 
180 dB re: 1 [mu]Pa (rms) within the boundaries of a SURTASS LFA sonar 
OBIA when:
    (1) Operationally necessary to continue tracking an existing 
underwater contact; or
    (2) Operationally necessary to detect a new underwater contact 
within the OBIA. This exception does not apply to routine training and 
testing with the SURTASS LFA sonar systems.


Sec.  218.235  Requirements for monitoring.

    (a) The Holder of a Letter of Authorization issued pursuant to 
Sec. Sec.  216.106 and 218.238 must:
    (1) Conduct visual monitoring from the ship's bridge during all 
daylight hours (30 minutes before sunrise until 30 minutes after 
sunset). During activities that employ SURTASS LFA sonar in the active 
mode, the SURTASS vessels shall have lookouts to maintain a topside 
watch with standard binoculars (7x) and with the naked eye.
    (2) Use low frequency passive SURTASS sonar to listen for 
vocalizing marine mammals; and
    (3) Use the HF/M3 sonar to locate and track marine mammals in 
relation to the SURTASS LFA sonar vessel and the sound field produced 
by the SURTASS LFA sonar source array, subject to the ramp-up 
requirements in Sec.  216.234(e) of this chapter.
    (b) Monitoring under paragraph (a) of this section must:
    (1) Commence at least 30 minutes before the first SURTASS LFA sonar 
transmission;
    (2) Continue between transmission pings; and
    (3) Continue either for at least 15 minutes after completion of the 
SURTASS LFA sonar transmission exercise, or, if marine mammals are 
exhibiting unusual changes in behavioral patterns, for a period of time 
until behavior patterns return to normal or conditions prevent 
continued observations.
    (c) Holders of Letters of Authorization for activities described in 
Sec.  218.230 are required to cooperate with the National Marine 
Fisheries Service and any other federal agency for monitoring the 
impacts of the activity on marine mammals.
    (d) The Navy must designate qualified on-site individuals to 
conduct the mitigation, monitoring and reporting activities specified 
in the Letter of Authorization.
    (e) Holders of Letters of Authorization will continue to assess 
data from the Marine Mammal Monitoring Program and work toward making 
some portion of that data, after appropriate security reviews, 
available to scientists with appropriate clearances. Any portions of 
the analyses conducted by these scientists based on these data that are 
determined to be unclassified after appropriate security reviews will 
be made publically available.
    (f) Holders of Letters of Authorization will collect ambient noise 
data and will explore the feasibility of declassifying and archiving 
the ambient noise data for incorporation into appropriate ocean noise 
budget efforts.
    (g) Holders of Letters of Authorization must conduct all monitoring 
required under the Letter of Authorization.


Sec.  218.236  Requirements for reporting.

    (a) The Holder of a Letter of Authorization must submit classified 
and unclassified quarterly mission reports to the Director, Office of 
Protected Resources, NMFS, no later than 45 days after the end of each 
quarter beginning on the date of effectiveness of a Letter of 
Authorization or as specified in the appropriate Letter of 
Authorization. Each quarterly mission report will include a summary of 
all active-mode missions completed during that quarter. At a minimum, 
each classified mission report must contain the following information: 
(1) Dates, times, and location of each vessel during each mission;
    (2) Information on sonar transmissions during each mission;
    (3) Results of the marine mammal monitoring program specified in 
the Letter of Authorization; and
    (4) Estimates of the percentages of marine mammal species and 
stocks affected (both for the quarter and cumulatively for the year) 
covered by the Letter of Authorization.
    (b) The Holder of a Letter of Authorization must submit an 
unclassified annual report to the Director, Office of Protected 
Resources, NMFS, no later than 60 days after the expiration of a Letter 
of Authorization. The reports must contain all the information required 
by the Letter of Authorization.
    (c) The fifth annual report shall be prepared as a final 
comprehensive report, which will include information for the final year 
as well as the prior four years of activities under the rule. This 
final comprehensive report must also contain an unclassified analysis 
of new passive sonar technologies and an assessment of whether such a 
system is feasible as an alternative to SURTASS LFA sonar, and shall be 
submitted to the Director, Office of Protected Resources, NMFS as 
described in paragraph (b) of this section.
    (d) The Navy will continue to assess the data collected by its 
undersea arrays and work toward making some portion of that data, after 
appropriate security reviews, available to scientists with appropriate 
clearances. Any portions of the analyses conducted by these scientists 
based on these data that are determined to be unclassified after 
appropriate security reviews will be made publically available. The 
Navy will provide a status update to NMFS when it submits an annual 
application for the Letters of Authorization.


Sec.  218.237  Applications for letters of authorization.

    (a) To incidentally take marine mammals pursuant to this subpart, 
the U.S. Navy authority conducting the activity identified in Sec.  
218.230 must apply for and obtain a Letter of Authorization in 
accordance with Sec.  216.106 of this chapter.
    (b) The application for a Letter of Authorization must be submitted 
to the Director, Office of Protected Resources, NMFS, at least 60 days 
before the date that either the vessel is scheduled to begin conducting 
SURTASS LFA sonar activities or the previous Letter of Authorization is 
scheduled to expire. If the Navy will change mission areas, or if there 
are other substantial modifications to the described activity, 
mitigation, or monitoring undertaken during the upcoming period, the 
Navy will submit its application for a Letter of Authorization at least 
90 days before the date that either the vessel is scheduled to begin 
conducting SURTASS LFA sonar activities or the previous Letter of 
Authorization is scheduled to expire.
    (c) All applications for a Letter of Authorization must include the 
following information:
    (1) The area(s) where the vessel's activity will occur;
    (2) The species and/or stock(s) of marine mammals likely to be 
found within each area;
    (3) The type of incidental taking authorization requested (i.e., 
take by Level B harassment);
    (4) The estimated percentage of marine mammal species/stocks 
potentially affected in each area for the period of effectiveness of 
the Letter of Authorization; and
    (5) The means of accomplishing the necessary monitoring and 
reporting that will result in increased knowledge of the species and 
the level of taking or impacts on marine mammal populations.

[[Page 19527]]

    (d) The National Marine Fisheries Service will review an 
application for a Letter of Authorization in accordance with Sec.  
216.104(b) of this chapter and, if adequate and complete, issue a 
Letter of Authorization.


Sec.  218.238  Letters of authorization.

    (a) A Letter of Authorization, unless suspended or revoked, will be 
valid for a period of time not to exceed one year, but may be renewed 
annually subject to renewal conditions in Sec.  218.239.
    (b) Each Letter of Authorization will set forth:
    (1) Permissible methods of incidental taking;
    (2) Authorized geographic areas for incidental takings;
    (3) Means of effecting the least practicable adverse impact on the 
species of marine mammals authorized for taking, their habitat, and the 
availability of the species for subsistence uses; and
    (4) Requirements for monitoring and reporting incidental takes.
    (c) Issuance of a letter of authorization will be based on a 
determination that the level of taking will be consistent with the 
findings made for the total taking allowable under this subpart.
    (d) Notice of issuance or denial of an application for a Letter of 
Authorization will be published in the Federal Register within 30 days 
of a determination.


Sec.  218.239  Renewal of letters of authorization.

    (a) A Letter of Authorization issued for the activity identified in 
Sec.  218.230 may be renewed upon:
    (1) Notification to NMFS that the activity described in the 
application submitted under Sec.  218.237 will be undertaken and that 
there will not be a substantial modification to the described activity, 
mitigation or monitoring undertaken during the upcoming period;
    (2) Notification to NMFS of the information identified in Sec.  
218.237(c);
    (3) Timely receipt of the monitoring reports required under Sec.  
218.236, which have been reviewed by NMFS and determined to be 
acceptable;
    (4) A determination by NMFS that the mitigation, monitoring and 
reporting measures required under Sec. Sec.  218.234, 218.235, and 
218.236 and the previous Letter of Authorization were undertaken and 
will be undertaken during the upcoming period of validity of a renewed 
Letter of Authorization; and
    (5) A determination by NMFS that the level of taking will be 
consistent with the findings made for the total taking allowable under 
this subpart, including for newly identified stocks that represent 
smaller divisions of species or stocks listed in Sec.  218.230(b).
    (b) If a request for a renewal of a Letter of Authorization 
indicates that a substantial modification to the described work, 
mitigation, or monitoring will occur, or if NMFS proposes a substantial 
modification to the Letter of Authorization, NMFS will provide a period 
of 30 days for public review and comment on the proposed modification. 
Modifying OBIAs is not considered a substantial modification to the 
Letter of Authorization.
    (c) A notice of issuance or denial of a renewal of a Letter of 
Authorization will be published in the Federal Register within 30 days 
of a determination.


Sec.  218.240  Modifications to letters of authorization.

    (a) Except as provided in paragraph (b) of this section, no 
substantial modification (including withdrawal or suspension) to a 
Letter of Authorization subject to the provisions of this subpart shall 
be made by NMFS until after notification and an opportunity for public 
comment has been provided.
    (b) If NMFS determines that an emergency exists that poses a 
significant risk to the well-being of the species or stocks of marine 
mammals specified in Sec.  218.230(b)(1), (2), or (3), NMFS may modify 
a Letter of Authorization without prior notice and opportunity for 
public comment. Notification will be published in the Federal Register 
within 30 days of the action.


Sec.  218.241  Adaptive management.

    NMFS may modify or augment the existing mitigation or monitoring 
measures (after consulting with the Navy regarding the practicability 
of the modifications) if doing so creates a reasonable likelihood of 
more effectively accomplishing the goals of mitigation and monitoring. 
NMFS will provide a period of 30 days for public review and comment if 
such modifications are substantial. Amending the areas for upcoming 
SURTASS LFA sonar activities or OBIA boundaries are not considered 
substantial modifications to the Letter of Authorization. Below are 
some of the possible sources of new data that could contribute to the 
decision to modify the mitigation or monitoring measures:
    (a) Results from the Navy's monitoring from the previous year's 
operation of SURTASS LFA sonar).
    (b) Compiled results of Navy-funded research and development 
studies.
    (c) Results from specific stranding investigations.
    (d) Results from general marine mammal and sound research funded by 
the Navy or other sponsors.
    (e) Any information that reveals marine mammals may have been taken 
in a manner, extent or number not anticipated by this subpart or 
subsequent Letters of Authorization.

[FR Doc. 2017-08066 Filed 4-26-17; 8:45 am]
BILLING CODE 3510-22-P