[Federal Register Volume 81, Number 38 (Friday, February 26, 2016)]
[Proposed Rules]
[Pages 9950-10023]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-03622]



[[Page 9949]]

Vol. 81

Friday,

No. 38

February 26, 2016

Part II





Department of Commerce





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National Oceanic and Atmospheric Administration





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50 CFR Part 218





Takes of Marine Mammals Incidental to Specified Activities; U.S. Navy 
Training Activities in the Gulf of Alaska Temporary Maritime Activities 
Area; Proposed Rule

  Federal Register / Vol. 81 , No. 38 / Friday, February 26, 2016 / 
Proposed Rules  

[[Page 9950]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 218

[Docket No. 141125997-6058-01]
RIN 0648-BE67


Takes of Marine Mammals Incidental to Specified Activities; U.S. 
Navy Training Activities in the Gulf of Alaska Temporary Maritime 
Activities Area

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

ACTION: Proposed rule; request for comments and information.

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SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for 
authorization to take marine mammals incidental to the training 
activities conducted in the Gulf of Alaska (GOA) Temporary Maritime 
Activities Area (TMAA) Study Area (hereafter referred to the Study 
Area) from May 2016 through May 2021. Pursuant to the Marine Mammal 
Protection Act (MMPA), NMFS is requesting comments on its proposal to 
issue regulations and subsequent Letter of Authorization (LOA) to the 
Navy to incidentally harass marine mammals.

DATES: Comments and information must be received no later than March 
28, 2016.

ADDRESSES: You may submit comments, identified by NOAA-NMFS-2016-0008, 
by any of the following methods:
     Electronic submissions: submit all electronic public 
comments via the Federal eRulemaking Portal, Go to www.regulations.gov/#!docketDetail;D=NOAA-NMFS-2016-0008, click the ``Comment Now!'' icon, 
complete the required fields, and enter or attach your comments.
     Mail: Submit comments to Jolie Harrison, Chief, Permits 
and Conservation Division, Office of Protected Resources, National 
Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 
20910-3225.
     Fax: (301) 713-0376; Attn: Jolie Harrison.
    Instructions: Comments sent by any other method, to any other 
address or individual, or received after the end of the comment period, 
may not be considered by NMFS. All comments received are a part of the 
public record and will generally be posted for public viewing on 
www.regulations.gov without change. All personal identifying 
information (e.g., name, address, etc.), confidential business 
information, or otherwise sensitive information submitted voluntarily 
by the sender will be publicly accessible. NMFS will accept anonymous 
comments (enter ``N/A'' in the required fields if you wish to remain 
anonymous). Attachments to electronic comments will be accepted in 
Microsoft Word, Excel, or Adobe PDF file formats only.

FOR FURTHER INFORMATION CONTACT: John Fiorentino, Office of Protected 
Resources, NMFS, (301) 427-8477.

SUPPLEMENTARY INFORMATION:

Availability

    A copy of the Navy's LOA application, which contains a list of the 
references used in this proposed rule, may be obtained by visiting the 
internet at: http://www.nmfs.noaa.gov/pr/permits/incidental/military.htm. The Navy is preparing a Supplemental Environmental Impact 
Statement (SEIS)/Overseas EIS (OEIS) for the GOA TMAA Study Area to 
evaluate all components of the proposed training activities. The Navy 
previously analyzed training activities in the Study Area in the 2011 
GOA Navy Training Activities FEIS (GOA FEIS/OEIS) (U.S. Department of 
the Navy, 2011a). The GOA Draft Supplemental EIS (DSEIS)/OEIS was 
released to the public on August 23, 2014, for review until October 22, 
2014. The Navy is the lead agency for the GOA SEIS/OEIS, and NMFS is a 
cooperating agency pursuant to 40 CFR 1501.6 and 1508.5. The GOA DSEIS/
OEIS, which also contains a list of the references used in this 
proposed rule, may be viewed at: http://www.goaeis.com. Documents cited 
in this notice may also be viewed, by appointment, during regular 
business hours, at the aforementioned address.

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, if the taking 
is limited to harassment, a notice of a proposed authorization is 
provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring, and reporting of such takings 
are set forth. 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 of 2004 (NDAA) (Pub. L. 108-
136) removed the ``small numbers'' and ``specified geographical 
region'' limitations indicated above and amended the definition of 
``harassment'' as applies to a ``military readiness activity'' to read 
as follows (section 3(18)(B) of the MMPA, 16 U.S.C. 1362(18)(B)): ``(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].

Summary of Request

    On July 28, 2014, NMFS received an application from the Navy 
requesting a LOA for the take of 19 species of marine mammals 
incidental to Navy training activities to be conducted in the Study 
Area over 5 years. On October 14, 2014, the Navy submitted a revised 
LOA application to reflect minor changes in the number and types of 
training activities. To address minor inconsistencies with the DSEIS, 
the Navy submitted a final revision to the LOA application (hereafter 
referred to as the LOA application) on January 21, 2015.
    The Navy is requesting a 5-year LOA for training activities to be 
conducted from 2016 through 2021. The Study Area is a polygon roughly 
the shape of a 300 nm by 150 nm rectangle oriented northwest to 
southeast in the long direction, located south of Prince William Sound 
and east of Kodiak Island, Alaska (see Figure 1-1 of the LOA 
application for a map of the Study Area). The activities conducted 
within the Study Area are classified as military readiness activities. 
The Navy states that these activities may expose some of the marine 
mammals present within the Study Area to sound from underwater

[[Page 9951]]

acoustic sources and explosives. The Navy requests authorization to 
take 19 marine mammal species by Level B (behavioral) harassment; one 
of those marine mammal species (Dall's porpoise) may be taken by Level 
A (injury) harassment. The Navy is not requesting mortality takes for 
any species.
    The LOA application and the GOA DSEIS/OEIS contain acoustic 
thresholds that, in some instances, represent changes from what NMFS 
has used to evaluate the Navy's activities for previous authorizations. 
The revised thresholds, which the Navy developed in coordination with 
NMFS, are based on the evaluation and inclusion of new information from 
recent scientific studies; a detailed explanation of how they were 
derived is provided in the GOA DSEIS/OEIS Criteria and Thresholds for 
U.S. Navy Acoustic and Explosive Effects Analysis Technical Report 
(available at http://www.goaeis.com). The revised thresholds are 
adopted for this proposed rulemaking.
    NOAA is currently in the process of developing Acoustic Guidance on 
thresholds for onset of auditory impacts from exposure to sound, which 
will be used to support assessments of the effects of anthropogenic 
sound on marine mammals. To develop this Guidance, NOAA is compiling, 
interpreting, and synthesizing the best information currently available 
on the effects of anthropogenic sound on marine mammals, and is 
committed to finalizing the Guidance through a systematic, transparent 
process that involves internal review, external peer review, and public 
comment.
    In December 2013, NOAA released for public comment a ``Draft 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammals: Acoustic Threshold Levels for Onset of Permanent and Temporary 
Threshold Shifts'' (78 FR 78822) (the term ``threshold shift'' refers 
to noise-induced hearing loss). The Draft Guidance was generally 
consistent with the Navy's Permanent Threshold Shifts/Temporary 
Threshold Shifts (PTS/TTS) criteria used in the GOA DSEIS/OEIS and 
detailed within Finneran and Jenkins (2012). Prior to the finalization 
of this guidance by NOAA, the Navy suggested revisions to the criteria 
(e.g., auditory weighting functions and PTS/TTS thresholds) based on a 
number of studies available since the Navy's Phase 2 modeling (the 
acoustic effects modeling currently employed by the Navy for training 
and testing activities), including Finneran et al. (2005), Finneran et 
al. (2010), Finneran and Schlundt (2013), Kastelein et al. (2012a), 
Kastelein et al. (2012b), Kastelein et al. (2014a), Kastelein et al. 
(2014b), Popov et al. (2013), and Popov et al. (2011). In January 2015, 
the Navy submitted a draft proposal (Finneran 2015) to NOAA staff for 
their consideration.
    Finneran (2015) proposed new weighting functions and thresholds for 
predicting PTS/TTS in marine mammals. The methodologies presented 
within this paper build upon the methodologies used to develop the 
criteria applied within the Navy's GOA DSEIS/OEIS (Finneran and 
Jenkins, 2012) and incorporate relevant auditory research made 
available since 2012. While Finneran and Jenkins (2012) presented a 
conservative approach to development of auditory weighting functions 
where data was limited, Finneran (2015) synthesizes a wide range of 
auditory data, including newly available studies, to predict refined 
auditory weighting functions and corresponding TTS thresholds across 
the complete hearing ranges of functional hearing groups.
    During the development process of NOAA's Draft Guidance, NOAA 
incorporated Finneran (2015) into its Draft Guidance. As a result, the 
Navy's proposal (Finneran, 2015) was submitted for peer review by 
external subject matter experts, in accordance with the process 
previously conducted for NOAA's Draft Guidance. Peer review comments 
were received by NOAA in April 2015. NOAA subsequently developed a Peer 
Review Report, which was published on its Web site on July 31, 2015. 
The published report documents the Navy's proposal (Finneran, 2015) 
that underwent peer review, the peer-review comments, and NOAA's 
responses to those comments. NOAA then incorporated this information 
into revised Draft Guidance which was published in the Federal Register 
for public review and comment (80 FR 45642) on July 31, 2015. The 
auditory weighting functions and PTS/TTS thresholds provided in that 
revised Draft Guidance will not be adopted by NOAA or applied to 
applicants until Final Guidance is issued. At the time of this proposed 
rulemaking, Final Guidance has not been issued. Therefore, the Navy has 
not adopted these proposed criteria in its GOA DSEIS/OEIS. However, the 
underlying science contained within Finneran (2015) has been addressed 
qualitatively within the applicable sections of the GOA DSEIS/OEIS and 
this rulemaking.
    If the proposed criteria in Finneran (2015) were adopted by NOAA, 
incorporated into its Final Guidance, and applied to the Navy in the 
future, predicted numbers of PTS/TTS would change for most functional 
hearing groups. However, because Finneran (2015) relies on much of the 
same data as the auditory criteria presented in the Navy's GOA DSEIS/
OEIS, these changes would not be substantial, and in most cases would 
result in a reduction in the predicted impacts. Predicted PTS/TTS would 
be reduced over much to all of their hearing range for low-frequency 
cetaceans and phocids. Predicted PTS/TTS for mid-frequency and high-
frequency cetaceans would be reduced for sources with frequencies below 
about 3.5 kHz and remain relatively unchanged for sounds above this 
frequency. Predicted auditory effects on otariids would increase for 
frequencies between about 1 kHz and 20 kHz and decrease for frequencies 
above and below these points, although otariids remain the marine 
mammals with the least sensitivity to potential PTS/TTS. Overall, 
predicted auditory effects within this rulemaking would not change 
significantly.
    In summary, NOAA's continuing evaluation of all available science 
for the Acoustic Guidance could result in changes to the acoustic 
criteria used to model the Navy's activities for this rulemaking, and, 
consequently, the enumerations of ``take'' estimates. However, at this 
time, the results of prior Navy modeling described in this notice 
represent the best available estimate of the number and type of take 
that may result from the Navy's use of acoustic sources in the GOA 
Study Area. Further, consideration of the revised Draft Guidance and 
information contained in Finneran (2015) does not alter our assessment 
of the likely responses of marine mammals to acoustic sources employed 
by Navy in the GOA Study Area, or the likely fitness consequences of 
those responses. Finally, while acoustic criteria may also inform 
mitigation and monitoring decisions, this rulemaking requires a robust 
adaptive management program that regularly addresses new information 
and allows for modification of mitigation and/or monitoring measures as 
appropriate.

Background of Request

    The Navy's mission is to organize, train, equip, and maintain 
combat-ready naval forces capable of winning wars, deterring 
aggression, and maintaining freedom of the seas. This mission is 
mandated by federal law (10 U.S.C. 5062), which ensures the readiness 
of

[[Page 9952]]

the naval forces of the United States.\1\ The Navy executes this 
responsibility by establishing and executing training programs, 
including at-sea training and exercises, and ensuring naval forces have 
access to the ranges, operating areas (OPAREAs), and airspace needed to 
develop and maintain skills for conducting naval activities.
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    \1\ Title 10, Section 5062 of the U.S.C.
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    The Navy proposes to continue conducting training activities within 
the Study Area, which have been ongoing since the 1990s. The tempo and 
types of training activities have fluctuated because of the 
introduction of new technologies, the evolving nature of international 
events, advances in war fighting doctrine and procedures, and force 
structure (organization of ships, submarines, aircraft, weapons, and 
personnel) changes. Such developments influence the frequency, 
duration, intensity, and location of required training activities.
    The Navy's LOA request covers training activities that would occur 
for a 5-year period following the expiration of the current MMPA 
authorization for the GOA TMAA, which expires in 2016.

Description of the Specified Activity

    The Navy is requesting authorization to take marine mammals 
incidental to conducting training activities. The Navy has determined 
that sonar use and underwater detonations are the stressors most likely 
to result in impacts on marine mammals that could rise to the level of 
harassment. Detailed descriptions of these activities are provided in 
the DSEIS/OEIS and in the LOA application (http://www.nmfs.noaa.gov/pr/permits/incidental/military.htm) and are summarized here.

Overview of Training Activities

    The Navy routinely trains in the Study Area in preparation for 
national defense missions. Training activities and exercises covered in 
the Navy's LOA request are briefly described below, and in more detail 
within chapter 2 of the GOA DSEIS/OEIS. Each military training activity 
described meets a requirement that can be traced ultimately to 
requirements set forth by the National Command Authority.\2\
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    \2\ ``National Command Authority'' is a term used by the United 
States military and government to refer to the ultimate lawful 
source of military orders. The term refers collectively to the 
President of the United States (as commander-in-chief) and the 
United States Secretary of Defense.
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    The Navy categorizes training activities into eight functional 
warfare areas called primary mission areas: anti-air warfare; 
amphibious warfare; strike warfare; anti-surface warfare (ASUW); anti-
submarine warfare (ASW); electronic warfare; mine warfare (MIW); and 
naval special warfare (NSW). Most training activities are categorized 
under one of these primary mission areas; those activities that do not 
fall within one of these areas are in a separate ``other'' category. 
Each warfare community (surface, subsurface, aviation, and special 
warfare) may train within some or all of these primary mission areas. 
However, not all primary mission areas are conducted within the Study 
Area.
    The Navy described and analyzed the effects of its training 
activities within the GOA DSEIS/OEIS. In its assessment, the Navy 
concluded that of the activities conducted within the Study Area, sonar 
use and underwater detonations were the stressors resulting in impacts 
on marine mammals that could rise to the level of harassment as defined 
under the MMPA. Therefore, the LOA application provides the Navy's 
assessment of potential effects from these stressors. The specific 
acoustic sources used in the LOA application are contained in the GOA 
DSEIS/OEIS and are presented in the following sections based on the 
primary mission areas.

Anti-Surface Warfare (ASUW)

    The mission of ASUW is to defend against enemy ships or boats. In 
the conduct of ASUW, aircraft use cannons, air-launched cruise missiles 
or other precision-guided munitions; ships employ torpedoes, naval 
guns, and surface-to-surface (S-S) missiles; and submarines attack 
surface ships using torpedoes or submarine-launched, anti-ship cruise 
missiles.
    Anti-surface warfare training in the Study Area includes S-S 
gunnery and missile exercises (GUNEX and MISSILEX) and air-to-surface 
(A-S) bombing exercises (BOMBEX), GUNEX, and MISSILEX. Also included in 
this mission area is a sinking exercise that may include S-S and A-S 
components.

Anti-Submarine Warfare (ASW)

    The mission of ASW is to locate, neutralize, and defeat hostile 
submarine threats to surface forces. ASW is based on the principle of a 
layered defense of surveillance and attack aircraft, ships, and 
submarines all searching for hostile submarines. These forces operate 
together or independently to gain early warning and detection, and to 
localize, track, target, and attack hostile submarine threats.
    Anti-submarine warfare training addresses basic skills such as 
detection and classification of submarines, distinguishing between 
sounds made by enemy submarines and those of friendly submarines, 
ships, and marine life. ASW training evaluates the ability of fleet 
assets to use systems, for example, active and passive sonar and 
torpedo systems to counter hostile submarine threats. More advanced, 
integrated ASW training exercises are conducted in coordinated, at-sea 
training events involving submarines, ships, and aircraft. This 
training integrates the full spectrum of ASW from detecting and 
tracking a submarine to attacking a target using simulated weapons.

Description of Sonar, Ordnance, Targets, and Other Systems

    The Navy uses a variety of sensors, platforms, weapons, and other 
devices to meet its mission. Training with these systems and devices 
may introduce acoustic (sound) energy into the environment. The Navy's 
current LOA application describes underwater sound as one of two types: 
impulsive and non-impulsive. Sonar and similar sound producing systems 
are categorized as non-impulsive sound sources. Underwater detonations 
of explosives and other percussive events are impulsive sounds.

Sonar and Other Active Acoustic Sources

    Modern sonar technology includes a variety of sonar sensor and 
processing systems. In concept, the simplest active sonar emits sound 
waves, or ``pings,'' sent out in multiple directions, and the sound 
waves then reflect off of the target object in multiple directions. The 
sonar source calculates the time it takes for the reflected sound waves 
to return; this calculation determines the distance to the target 
object. More sophisticated active sonar systems emit a ping and then 
rapidly scan or listen to the sound waves in a specific area. This 
provides both distance to the target and directional information. Even 
more advanced sonar systems use multiple receivers to listen to echoes 
from several directions simultaneously and provide efficient detection 
of both direction and distance. Active sonar is rarely used 
continuously throughout the listed activities. In general, when sonar 
is in use, the sonar `pings' occur at intervals, referred to as a duty 
cycle, and the signals themselves are very short in duration. For 
example, sonar that emits a 1-second ping every 10 seconds has a 10 
percent duty cycle. The Navy's largest hull-mounted mid-frequency sonar 
source typically emits a 1-second ping every 50 seconds representing a 
2 percent duty cycle. The Navy utilizes sonar systems and other 
acoustic sensors in support of a variety of

[[Page 9953]]

mission requirements. Primary uses include the detection of and defense 
against submarines (ASW) and mines (MIW); safe navigation and effective 
communications; use of unmanned undersea vehicles; and oceanographic 
surveys. Sources of sonar and other active acoustic sources include 
surface ship sonar, sonobuoys, torpedoes, and unmanned underwater 
vehicles.

Ordnance and Munitions

    Most ordnance and munitions used during training events fall into 
three basic categories: Projectiles (such as gun rounds), missiles 
(including rockets), and bombs. Ordnance can be further defined by 
their net explosive weight (NEW), which considers the type and quantity 
of the explosive substance without the packaging, casings, bullets, 
etc. NEW is the trinitrotoluene (TNT) equivalent of energetic material, 
which is the standard measure of strength of bombs and other 
explosives. For example, a 5-inch shell fired from a Navy gun is 
analyzed at approximately 9.5 pounds (lb.) (4.3 kilograms [kg]) of NEW. 
The Navy also uses non-explosive ordnance in place of explosive 
ordnance in many training and testing events. Non-explosive ordnance 
look and perform similarly to explosive ordnance, but lack the main 
explosive charge.

Defense Countermeasures

    Naval forces depend on effective defensive countermeasures to 
protect themselves against missile and torpedo attack. Defensive 
countermeasures are devices designed to confuse, distract, and confound 
precision-guided munitions. Defensive countermeasures analyzed in this 
LOA application include acoustic countermeasures, which are used by 
surface ships and submarines to defend against torpedo attack. Acoustic 
countermeasures are either released from ships and submarines, or towed 
at a distance behind the ship.

Classification of Non-Impulsive and Impulsive Sources Analyzed

    In order to better organize and facilitate the analysis of 
approximately 300 individual sources of underwater acoustic sound or 
explosive energy, a series of source classifications, or source bins, 
were developed by the Navy. The use of source classification bins 
provides the following benefits:
     Provides the ability for new sensors or munitions to be 
covered under existing regulatory authorizations, as long as those 
sources fall within the parameters of a ``bin'';
     Simplifies the source utilization data collection and 
reporting requirements anticipated under the MMPA;
     Ensures a conservative approach to all impact analysis, as 
all sources in a single bin are modeled as the loudest source (e.g., 
lowest frequency, highest source level [the term ``source level'' 
refers to the loudness of a sound at its source], longest duty cycle, 
or largest net explosive weight [NEW]) within that bin, which:
    [cir] Allows analysis to be conducted more efficiently, without 
compromising the results; and
    [cir] Provides a framework to support the reallocation of source 
usage (hours/explosives) between different source bins, as long as the 
total number and severity of marine mammal takes remain within the 
overall analyzed and authorized limits. This flexibility is required to 
support evolving Navy training requirements, which are linked to real 
world events.
    There are two primary types of acoustic sources: Impulsive and non-
impulsive. A description of each source classification is provided in 
Tables 1 and 2. Impulsive source class bins are based on the NEW of the 
munitions or explosive devices or the source level for air and water 
guns. Non-impulsive acoustic sources are grouped into source class bins 
based on the frequency,\3\ source level,\4\ and, when warranted, the 
application in which the source would be used. The following factors 
further describe the considerations associated with the development of 
non-impulsive source bins:
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    \3\ Bins are based on the typical center frequency of the 
source. Although harmonics may be present, those harmonics would be 
several decibels (dB) lower than the primary frequency.
    \4\ Source decibel levels are expressed in terms of sound 
pressure level (SPL) and are values given in dB referenced to 1 
micropascal at 1 meter.

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 Frequency of the non-impulsive source.

[cir] Low-frequency sources operate below 1 kilohertz (kHz)
[cir] Mid-frequency sources operate at and above 1 kHz, up to and 
including 10 kHz
[cir] High-frequency sources operate above 10 kHz, up to and including 
100 kHz
[cir] Very high-frequency sources operate above 100 kHz but below 200 
kHz


 Source level of the non-impulsive source.

[cir] Greater than 160 decibels (dB), but less than 180 dB
[cir] Equal to 180 dB and up to 200 dB
[cir] Greater than 200 dB

 Application in which the source would be used.
    [cir] How a sensor is employed supports how the sensor's acoustic 
emissions are analyzed.
    [cir] Factors considered include pulse length (time source is on); 
beam pattern (whether sound is emitted as a narrow, focused beam or, as 
with most explosives, in all directions); and duty cycle (how often or 
how many times a transmission occurs in a given time period during an 
event).
    As described in the GOA DSEIS/OEIS, non-impulsive acoustic sources 
that have low source levels (not loud), narrow beam widths, downward 
directed transmission, short pulse lengths, frequencies beyond known 
hearing ranges of marine mammals, or some combination of these 
characteristics, are not anticipated to result in takes of protected 
species and therefore were not modeled. These sources generally meet 
the following criteria and are qualitatively analyzed in the GOA DSEIS/
OEIS:

 Acoustic sources with frequencies greater than 200 kHz (based 
on known marine mammal hearing ranges)
 Sources with source levels less than 160 dB

     Table 1--Impulsive (Explosive) Training Source Classes Analyzed
------------------------------------------------------------------------
                              Representative      Net explosive weight
       Source class             munitions                 (lbs)
------------------------------------------------------------------------
E5.......................  5-inch projectiles.  >5-10
E6.......................  AGM-114 Hellfire     >10-20
                            missile.
E7.......................  AGM-88 High-speed    >20-60
                            Anti-Radiation
                            Missile.
E8.......................  250 lb. bomb.......  >60-100
E9.......................  500 lb. bomb.......  >100-250

[[Page 9954]]

 
E10......................  1,000 lb. bomb/Air-  >250-500
                            to-surface missile.
E11......................  MK-48 torpedo......  >500-650
E12......................  2,000 lb. bomb.....  >650-1,000
------------------------------------------------------------------------


        Table 2--Non-Impulsive Training Source Classes Analyzed.
------------------------------------------------------------------------
                                                      Description of
      Source class category        Source class   representative sources
------------------------------------------------------------------------
Mid-Frequency (MF): Tactical and  MF1            Hull-mounted surface
 non-tactical sources that                        ship sonar (e.g., AN/
 produce mid-frequency (1-10                      SQS-53C and AN/SQS-
 kHz) signals.                                    60).
                                  MF3            Hull-mounted submarine
                                                  sonar (e.g., AN/BQQ-
                                                  10).
                                  MF4            Helicopter-deployed
                                                  dipping sonar (e.g.,
                                                  AN/AQS-22 and AN/AQS-
                                                  13).
                                  MF5            Active acoustic
                                                  sonobuoys (e.g.,
                                                  DICASS).
                                  MF6            Active underwater sound
                                                  signal devices (e.g.,
                                                  MK-84).
                                  MF11           Hull-mounted surface
                                                  ship sonar with an
                                                  active duty cycle
                                                  greater than 80%.
High-Frequency (HF): Tactical     HF1            Hull-mounted submarine
 and non-tactical sources that    HF6             sonar (e.g., AN/BQQ-
 produce high[dash]frequency                      10).
 (greater than 10 kHz but less                   Active sources (equal
 than 100 kHz) signals.                           to 180 dB and up to
                                                  200 dB).
Anti-Submarine Warfare (ASW):     ASW2
 Tactical sources such as active
 sonobuoys and acoustic
 countermeasures systems used
 during the conduct of ASW
 training activities.
                                  ASW3           Mid-frequency
                                                  Multistatic Active
                                                  Coherent sonobuoy
                                                  (e.g., AN/SSQ-125).
                                                 Mid-frequency towed
                                                  active acoustic
                                                  countermeasure systems
                                                  (e.g., AN/SLQ-25).
                                  ASW4           Mid-frequency
                                                  expendable active
                                                  acoustic device
                                                  countermeasures (e.g.,
                                                  MK-3).
Torpedoes (TORP): Source classes  TORP2          Heavyweight torpedo
 associated with the active                       (e.g., MK-48, electric
 acoustic signals produced by                     vehicles).
 torpedoes.
------------------------------------------------------------------------
Notes: dB = decibels, DICASS = Directional Command Activated Sonobuoy
  System, kHz = kilohertz

Training

    The training activities that the Navy proposes to conduct in the 
Study Area are described in Table 3. The table is organized according 
to primary mission areas and includes the activity name, associated 
stressor(s), description of the activity, the primary platform used 
(e.g., ship or aircraft type), duration of activity, type of non-
impulsive or impulsive sources used in the activity, and the number of 
activities per year. More detailed activity descriptions can be found 
in chapter 2 of the GOA DSEIS/OEIS. The Navy's Proposed Activities are 
anticipated to meet training needs in the years 2016-2021.

                               Table 3--Training Activities Within the Study Area
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                                                                                           Weapons/rounds/sound
              Category                  Training activity            Description                  source
----------------------------------------------------------------------------------------------------------------
Anti-Surface Warfare (ASUW)
    Impulsive......................  Gunnery Exercise,       Ship crews engage surface    Small-, Medium-, and
                                      Surface-to-Surface      targets with ship's small-   Large-caliber high
                                      (Ship) (GUNEX-S-S       , medium-, and large-        explosive rounds.
                                      [Ship]).                caliber guns. Some of the
                                                              small- and medium-caliber
                                                              gunnery exercises analyzed
                                                              include those conducted by
                                                              the U.S. Coast Guard.
    Impulsive......................  Sinking Exercise......  Fixed-wing aircrews,         High explosive bombs,
                                                              surface ships and            missiles, Large-
                                                              submarine firing precision-  caliber rounds and
                                                              guided and non-precision     torpedoes.
                                                              weapons against a surface
                                                              target.
    Impulsive......................  Bombing Exercise (Air-  Fixed-wing aircrews deliver  High explosive bombs.
                                      to-Surface) (BOMBEX     bombs against surface
                                      [A-S]).                 targets.
Anti-Submarine Warfare (ASW)
    Non-impulsive..................  Tracking Exercise--     Submarine searches for,      Mid- and high-
                                      Submarine (TRACKEX--    detects, and tracks          frequency submarine
                                      Sub).                   submarine(s) and surface     sonar.
                                                              ship(s).

[[Page 9955]]

 
    Non-impulsive..................  Tracking Exercise--     Surface ship searches for,   Mid-frequency surface
                                      Surface (TRACKEX--      tracks, and detects          ship sonar, acoustic
                                      Surface).               submarine(s).                countermeasures, and
                                                                                           high-frequency active
                                                                                           sources.
    Non-impulsive..................  Tracking Exercise--     Helicopter searches,         Mid-frequency dipping
                                      Helicopter (TRACKEX--   tracks, and detects          sonar systems and
                                      Helo).                  submarine(s).                sonobuoys.
    Non-impulsive..................  Tracking Exercise--     Maritime patrol aircraft     Sonobuoys, such as
                                      Maritime Patrol         use sonobuoys to search      DICASS sonobuoys.
                                      Aircraft (TRACKEX--     for, detect, and track
                                      MPA).                   submarine(s).
    Non-impulsive..................  Tracking Exercise--     Maritime patrol aircraft     mid-frequency MAC
                                      Maritime Patrol         crews search for, detect     sonobuoys.
                                      Aircraft (MAC           and track submarines using
                                      Sonobuoys).             MAC sonobuoys.
----------------------------------------------------------------------------------------------------------------
Notes: DICASS = Directional Command Activated Sonobuoy System; MAC=Multistatic Active Coherent

Summary of Impulsive and Non-Impulsive Sources

    Table 4 provides a quantitative annual summary of training 
activities by sonar and other active acoustic source class analyzed in 
the Navy's LOA request.

   Table 4--Annual Hours of Sonar and Other Active Acoustic Sources Used During Training Within the Study Area
----------------------------------------------------------------------------------------------------------------
          Source class category                  Source class                    Units              Annual use
----------------------------------------------------------------------------------------------------------------
Mid-Frequency (MF) Active sources from 1  MF1.......................  Hours.....................             541
 to 10 kHz.
                                          MF3.......................  Hours.....................              48
                                          MF4.......................  Hours.....................              53
                                          MF5.......................  Items.....................              25
                                          MF6.......................  Items.....................              21
                                          MF11......................  Hours.....................              78
High-Frequency (HF): Tactical and non-    HF1.......................  Hours.....................              24
 tactical sources that produce signals    HF6.......................  Hours.....................              80
 greater than 10 kHz but less than 100
 kHz.
Anti-Submarine Warfare (ASW) Active ASW   ASW2......................  Hours.....................              80
 sources.
                                          ASW3......................  Hours.....................             546
                                          ASW4......................  Items.....................               4
Torpedoes (TORP) Source classes           TORP2.....................  Items.....................               5
 associated with active acoustic signals
 produced by torpedoes.
----------------------------------------------------------------------------------------------------------------

    Table 5 provides a quantitative annual summary of training 
explosive source classes analyzed in the Navy's LOA request.

  Table 5--Annual Number of Training Explosive Source Detonations Used
                  During Training Within the Study Area
------------------------------------------------------------------------
                                                            Annual  in-
                                                               water
  Explosive class  net explosive weight  (pounds [lb.])     detonations
                                                             training
------------------------------------------------------------------------
E5 (> 5-10 lb.).........................................             112
E6 (> 10-20 lb.)........................................               2
E7 (> 20-60 lb.)........................................               4
E8 (> 60-100 lb.).......................................               6
E9 (> 100-250 lb.)......................................             142
E10 (> 250-500 lb.).....................................              32
E11 (> 500-650 lb.).....................................               2
E12 (> 650-1,000 lb.)...................................               4
------------------------------------------------------------------------

Duration and Location

    Training activities would be conducted in the Study Area during two 
exercises of up to 21 days each per year (for a total of up to 42 days 
per year) to support a major joint training exercise in Alaska and off 
the Alaskan coast that involves the Departments of the Navy, the Army 
and the Air Force, and the U.S. Coast Guard (Coast Guard). The Service 
participants report to a unified or joint commander who coordinates the 
activities planned to demonstrate and evaluate the ability of the 
services to engage in a conflict and carry out plans in response to a 
threat to national security. The exercises would occur between the 
months of May and October of each year from 2016 to 2021.
    The Study Area (see Figure 1-1 of the LOA application) is entirely 
at sea and is composed of the established GOA TMAA and a warning area 
in the Gulf of Alaska. The Navy uses ``at-sea'' to include its training 
activities in the Study Area that occur (1) on the ocean surface, (2) 
beneath the ocean surface, and (3) in the air above the ocean surface. 
Navy training activities occurring on or over the land outside the GOA 
TMAA are covered under previously prepared environmental documentation 
prepared by the U.S. Air Force and the U.S. Army.

Gulf of Alaska Temporary Maritime Activities Area (GOA TMAA)

    The GOA TMAA is a temporary area established in conjunction with 
the Federal Aviation Administration (FAA) for up to two exercise 
periods of up to 21 days each, for a total of 42 days per year, that is 
a surface, undersea space, and airspace maneuver area within the Gulf 
of Alaska for ships, submarines, and aircraft to conduct required 
training activities. The GOA TMAA is a polygon roughly resembling a 
rectangle oriented from northwest to southeast,

[[Page 9956]]

approximately 300 nautical miles (nm) in length by 150 nm in width, 
located south of Prince William Sound and east of Kodiak Island.

Airspace of the GOA TMAA

    The airspace of the GOA TMAA overlies the surface and subsurface 
training area and is called an Altitude Reservation (ALTRV). This ALTRV 
is a temporary airspace designation, typically requested by the Alaskan 
Command (ALCOM) and coordinated through the FAA for the duration of the 
exercise. This overwater airspace supports the majority of aircraft 
training activities conducted by Navy and Joint aircraft throughout the 
joint training exercise. The ALTRV over the GOA TMAA typically extends 
from the ocean surface to 60,000 feet (ft.) (18,288 meters [m]) above 
mean sea level and encompasses 42,146 square nautical miles (nm\2\) of 
airspace. For safety considerations, ALTRV information is sent via 
Notice to Airmen (NOTAM)/International NOTAM so that all pilots are 
aware of the area and that Air Traffic Control will keep known 
Instrument Flight Rules aircraft clear of the area.
    Additionally, the GOA TMAA overlies a majority of Warning Area W-
612 (W-612) located over Blying Sound, towards the northwestern 
quadrant of the GOA TMAA. When not included as part of the GOA TMAA, W-
612 provides 2,256 nm\2\ of special use airspace for the Air Force and 
Coast Guard to fulfill some of their training requirements. Air Force, 
Army, National Guard, and Coast Guard activities conducted as part of 
at-sea joint training within the GOA TMAA are included in the DSEIS/
OEIS analysis. No Navy training activities analyzed in this proposed 
rule occur in the area of W-612 that is outside of the GOA TMAA (see 
Figure 1-1 of the LOA application).

Sea and Undersea Space of the GOA TMAA

    The GOA TMAA surface and subsurface areas are also depicted in 
Figure 1-1 of the LOA application. Total surface area of the GOA TMAA 
is 42,146 nm\2\. Due to weather conditions, annual joint training 
activities are typically conducted during the summer months (April-
October). The GOA TMAA undersea area lies beneath the surface area as 
depicted in Figure 1-1 of the LOA application. The undersea area 
extends to the seafloor.
    The complex bathymetric and oceanographic conditions, including a 
continental shelf, submarine canyons, numerous seamounts, and fresh 
water infusions from multiple sources, create a challenging environment 
in which to search for and detect submarines in ASW training 
activities. In the summer, the GOA TMAA provides a safe cold-water 
training environment that resembles other areas where Navy may need to 
operate in a real-world scenario.
    The GOA TMAA meets large-scale joint exercise training objectives 
to support naval and joint operational readiness by providing a 
``geographically realistic'' training area for U.S. Pacific Command, 
Joint Task Force Commander scenario-based training, and supports the 
mission requirement of Alaskan Command (ALCOM) to conduct joint 
training for Alaska-based forces. The strategic vision of the 
Commander, U.S. Pacific Fleet is that the training area support naval 
operational readiness by providing a realistic, live-training 
environment for forces assigned to the Pacific Fleet and other users 
with the capability and capacity to support current, emerging, and 
future training requirements.

Description of Marine Mammals in the Area of the Specified Activities

    Marine mammal species known to occur in the Study Area and their 
currently recognized stocks are presented in Table 6 consistent with 
the NMFS' U.S. Pacific Marine Mammal Stock Assessment Report (Carretta 
et al., 2015) and the Alaska Marine Mammal Stock Assessment Report 
(Muto and Angliss, 2015). Twenty-two marine mammal species have 
confirmed or possible occurrence within or adjacent to the Study Area, 
including seven species of baleen whales (mysticetes), eight species of 
toothed whales (odontocetes), six species of seals (pinnipeds), and the 
sea otter (mustelid). Nine of these species are listed under the ESA: 
Blue whale, fin whale, humpback whale, sei whale, sperm whale, gray 
whale (Western North Pacific stock), North Pacific right whale, Steller 
sea lion (Western U.S. stock), and sea otter. All these species are 
managed by NMFS or the U.S. Fish and Wildlife Service (USFWS) in the 
U.S. Exclusive Economic Zone (EEZ).
    The species carried forward for analysis are those likely to be 
found in the Study Area based on the most recent data available, and do 
not include stocks or species that may have once inhabited or transited 
the area but have not been sighted in recent years (e.g., species which 
were extirpated because of factors such as nineteenth and twentieth 
century commercial exploitation). Several species that may be present 
in the Gulf of Alaska have an extremely low probability of presence in 
the Study Area. These species are considered extralimital, meaning 
there may be a small number of sighting or stranding records within the 
Study Area, but the area of concern is outside the species' range of 
normal occurrence. These species include beluga whale (Delphinapterus 
leucas), false killer whale (Pseudorca crassidens), short-finned pilot 
whale (Globicephala macrorhynchus), northern right whale dolphin 
(Lissodelphis borealis), and Risso's dolphin (Grampus griseus), and 
have been excluded from subsequent analysis.

                                    Table 6--Marine Mammals With Possible or Confirmed Presence Within the Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                      Stock abundance \3\   Occurrence in  region
            Common name                Scientific name \1\          Stock \2\                 (CV)                   \4\              ESA/MMPA Status
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Order Cetacea
                                                           Suborder Mysticeti (baleen whales)
                                                            Family Balaenidae (right whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Pacific right whale..........  Eubalaena japonica....  Eastern North Pacific.  31 (0.23)............  Rare.................  Endangered/Depleted.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Family Balaenopteridae (rorquals)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale.....................  Megaptera novaeangliae  Central North Pacific.  10,252 (0.042).......  Likely...............  Endangered/ Depleted.
                                                             Western North Pacific.  893 (0.079)..........  Likely...............  Endangered/ Depleted.

[[Page 9957]]

 
Blue whale.........................  Balaenoptera musculus.  Eastern North Pacific.  1,647 (0.07).........  Seasonal; highest      Endangered/ Depleted.
                                                                                                             likelihood July to
                                                                                                             December.
                                                             Central North Pacific.  81 (1.14)............  Seasonal; highest      Endangered/ Depleted.
                                                                                                             likelihood July to
                                                                                                             December.
Fin whale..........................  Balaenoptera physalus.  Northeast Pacific.....  1,368 (minimum         Likely...............  Endangered/ Depleted.
                                                                                      estimate) (n/a).
Sei whale..........................  Balaenoptera borealis.  Eastern North Pacific.  126 (0.53)...........  Rare.................  Endangered/ Depleted.
Minke whale........................  Balaenoptera            Alaska................  Not available........  Likely.
                                      acutorostrata.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           Family Eschrichtiidae (gray whale)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gray whale.........................  Eschrichtius robustus.  Eastern North Pacific.  20,990 (0.05)........  Likely: Highest
                                                                                                             numbers during
                                                                                                             seasonal migrations.
                                                             Western North Pacific.  140 (0.043)..........  Rare: Individuals      Endangered/ Depleted.
                                                                                                             migrate through GOA.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Suborder Odontoceti (toothed whales)
                                                            Family Physeteridae (sperm whale)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale........................  Physeter macrocephalus  North Pacific.........  Not available........  Likely; More likely    Endangered/ Depleted.
                                                                                                             in waters > 1,000 m
                                                                                                             depth, most often >
                                                                                                             2,000 m.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Family Delphinidae (dolphins)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Killer whale.......................  Orcinus orca..........  Alaska Resident.......  2,347 (n/a)..........  Likely.
                                                             Eastern North Pacific   211: includes known    Infrequent: few
                                                              Offshore.               offshore killer        sightings.
                                                                                      whales along the
                                                                                      U.S. west coast,
                                                                                      Canada, and Alaska
                                                                                      (n/a).
                                                             AT1 Transient.........  7....................  Rare; more likely
                                                                                                             inside Prince
                                                                                                             William Sound and
                                                                                                             Kenai Fjords.
                                                             GOA, Aleutian Island,   587..................  Likely.
                                                              and Bering Sea
                                                              Transient.
Pacific white[dash]sided dolphin...  Lagenorhynchus          North Pacific.........  26,880; specific to    Likely.
                                      obliquidens.                                    the GOA, not the
                                                                                      management stock (n/
                                                                                      a).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Family Phocoenidae (porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor porpoise....................  Phocoena phocoena.....  GOA...................  31,046 (0.21)........  Likely in nearshore
                                                                                                             locations.
                                                             Southeast Alaska......  11,146 (0.24)........  Likely in nearshore
                                                                                                             locations.
Dall's porpoise....................  Phocoenoides dalli....  Alaska................  83,400 (0.097); based  Likely.
                                                                                      on survey data from
                                                                                      1987-1991.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Family Ziphiidae (beaked whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cuvier's beaked whale..............  Ziphius cavirostris...  Alaska................  Not available........  Likely.
Baird's beaked whale...............  Berardius bairdii.....  Alaska................  Not available........  Likely.
Stejneger's beaked whale...........  Mesoplodon stejnegeri.  Alaska................  Not available........  Likely.
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 9958]]

 
                                                                     Order Carnivora
                                                                 Suborder Pinnipedia \5\
                                                       Family Otariidae (fur seals and sea lions)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steller sea lion...................  Eumetopias jubatus....  Eastern U.S...........  59,968 (minimum        Likely.
                                                                                      estimate) (n/a).
                                                             Western U.S...........  49,497 (minimum        Likely...............  Endangered/ Depleted.
                                                                                      estimate) (n/a).
California sea lion................  Zalophus californianus  U.S...................  296,750 (n/a)........  Rare.
Northern fur seal..................  Callorhinus ursinus...  Eastern Pacific.......  648,534 (n/a)........  Likely...............  Depleted.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Family Phocidae (true seals)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Northern elephant seal.............  Mirounga                California Breeding...  179,000 (n/a)........  Likely.
                                      angustirostris.
Harbor seal........................  Phoca vitulina........  Aleutian Islands......  6,431 (n/a)..........  Extralimital
                                                             Pribilof Islands......  232 (n/a)............  Extralimital.
                                                             Bristol Bay...........  32,350 (n/a).........  Extralimital.
                                                             N. Kodiak.............  8,321 (n/a)..........  Rare (inshore
                                                                                                             waters).
                                                             S. Kodiak.............  19,199 (n/a).........  Rare (inshore
                                                                                                             waters).
                                                             Prince William Sound..  29,889 (n/a).........  Rare (inshore
                                                                                                             waters).
                                                             Cook Inlet/Shelikof...  27,386 (n/a).........  Extralimital.
                                                             Glacier Bay/Icy Strait  7,210 (n/a)..........  Rare (inshore
                                                                                                             waters).
                                                             Lynn Canal/ Stephens..  9,478 (n/a)..........  Extralimital.
                                                             Sitka/Chatham.........  14,855 (n/a).........  Rare (inshore
                                                                                                             waters).
                                                             Dixon/Cape Decision...  18,105 (n/a).........  Rare (inshore
                                                                                                             waters).
                                                             Clarence Strait.......  31,634 (n/a).........  Extralimital.
Ribbon seal........................  Histriophoca fasciata.  Alaska................  184,000..............  Rare.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Family Mustelidae (otters) \6\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Northern sea otter.................  Enhydra lutris kenyoni  Southeast Alaska......  10,563...............  Rare.
                                                             Southcentral Alaska...  15,090...............  Rare.
                                                             Southwest Alaska......  47,676...............  Rare.................  Threatened.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Taxonomy follows Perrin et al. (2009).
\2\ Stock names and abundance estimates from Muto and Angliss (2015) and Carretta et al. (2015) except where noted.
\3\ The stated coefficient of variation (CV) from the NMFS Stock Assessement Reports is an indicator of uncertainty in the abundance estimate and
  describes the amount of variation with respect to the population mean. It is expressed as a fraction or sometimes a percentage and can range upward
  from zero, indicating no uncertainty, to high values. For example, a CV of 0.85 would indicate high uncertainty in the population estimate. When the
  CV exceeds 1.0, the estimate is very uncertain. The uncertainty associated with movements of animals into or out of an area (due to factors such as
  availability of prey or changing oceanographic conditions) is much larger than is indicated by the CVs that are given.
\4\ EXTRALIMITAL: There may be a small number of sighting or stranding records, but the area is outside the species range of normal occurrence. RARE:
  The distribution of the species is near enough to the area that the species could occur there, or there are a few confirmed sightings. INFREQUENT:
  Confirmed, but irregular sightings or acoustic detections. LIKELY: Confirmed and regular sightings or acoustic detections of the species in the area
  year-round. SEASONAL: Confirmed and regular sightings or acoustic detections of the species in the area on a seasonal basis.
\5\ There are no data regarding the CV for some of the pinniped species given that abundance is determined by different methods than those used for
  cetaceans.
\6\ There are no data regarding the CV for sea otter given that abundance is determined by different methods than those used for cetaceans.
Notes: CV = coefficient of variation, ESA = Endangered Species Act, GOA = Gulf of Alaska, m = meter(s), MMPA = Marine Mammal Protection Act, n/a = not
  available, U.S. = United States.

    Information on the status, distribution, abundance, and 
vocalizations of marine mammal species in the Study Area may be viewed 
in Chapter 4 of the LOA application (http://www.nmfs.noaa.gov/pr/permits/incidental/military.htm). Additional information on the general 
biology and ecology of marine mammals are included in the GOA DSEIS/
OEIS. In addition, NMFS annually publishes Stock Assessment Reports 
(SARs) for all marine mammals in U.S. EEZ waters, including stocks that 
occur within the Study Area (U.S. Pacific Marine Mammal Stock 
Assessments, Carretta et al., 2015; Alaska Marine Mammal Stock 
Assessments, Muto and Angliss, 2015).

Marine Mammal Hearing and Vocalizations

    Cetaceans have an auditory anatomy that follows the basic mammalian 
pattern, with some changes to adapt to the demands of hearing 
underwater. The typical mammalian ear is divided into an outer ear, 
middle ear, and inner ear.

[[Page 9959]]

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 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).
    Marine mammal vocalizations often extend both above and below the 
range of human hearing; vocalizations with frequencies lower than 20 Hz 
are labeled as infrasonic and those higher than 20 kHz as ultrasonic 
(National Research Council (NRC), 2003; Figure 4-1). 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. The ears of small toothed whales are optimized for 
receiving high-frequency sound, while baleen whale inner ears are best 
in low to infrasonic frequencies (Ketten, 1992; 1997; 1998).
    Baleen whale vocalizations are composed primarily of frequencies 
below 1 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 baleen 
whales is extremely lacking. 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 microPascal ([micro]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).
    The toothed whales 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 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 whale social 
vocalizations is concentrated near 10 kHz, with source levels for 
whistles as high as 100 to 180 dB re 1 [micro]Pa at 1 m (Richardson et 
al., 1995). No odontocete has been shown audiometrically to have acute 
hearing (<80 dB re 1 [micro]Pa) below 500 Hz (DoN, 2001). 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 [micro]Pa 1 m or greater (Mohl et al., 2000).

Brief Background on Sound

    An understanding of the basic properties of underwater sound is 
necessary to comprehend many of the concepts and analyses presented in 
this proposed rule. A summary is included below.
    Sound is a wave of pressure variations propagating through a medium 
(e.g., water). 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, but rather from ratios of pressures; the 
standard reference pressure for underwater sound is 1 [micro]Pa; for 
airborne sound, the standard reference pressure is 20 [micro]Pa 
(Richardson et al., 1995).
    Acousticians have adopted a logarithmic scale for sound 
intensities, which is denoted in decibels (dB). Decibel measurements 
represent the ratio between a measured pressure value and a reference 
pressure value (in this case 1 [micro]Pa or, for airborne sound, 20 
[micro]Pa). The logarithmic nature of the scale means that each 10-dB 
increase is a ten-fold increase in acoustic power (and a 20-dB increase 
is then a 100-fold increase in power; and a 30-dB increase is a 1,000-
fold increase in power). A ten-fold increase in acoustic power does not 
mean that the sound is perceived as being ten times louder, however. 
Humans perceive a 10-dB increase in sound level as a doubling of 
loudness, and a 10-dB decrease in sound level as a halving of loudness. 
The term ``sound pressure level'' implies a decibel measure and a 
reference pressure that is used as the denominator of the ratio. 
Throughout this proposed rule, NMFS uses 1 [micro]Pa (denoted re: 
1[micro]Pa) as a standard reference pressure unless noted otherwise.
    It is important to note that decibel values underwater and decibel 
values in air are not the same (different reference pressures and 
densities/sound speeds between media) and should not be directly 
compared. Because of the different densities of air and water and the 
different decibel standards (i.e., reference pressures) in air and 
water, a sound with the same level in air and in water would be 
approximately 62 dB lower in air. Thus, a sound that measures 160 dB 
(re 1 [micro]Pa) underwater would have the same approximate effective 
level as a sound that is 98 dB (re 20 [micro]Pa) in air.

[[Page 9960]]

    Sound frequency is measured in cycles per second, or Hertz 
(abbreviated 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 huge range of 
frequencies: From earthquake noise at 5 Hz to harbor porpoise clicks at 
150,000 Hz (150 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) and ultrasonic (typically above 20,000 Hz) 
sounds, respectively. A single sound may be made up of many different 
frequencies together. 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 active tactical sonars are an example of a 
narrowband sound source.
    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. Current 
data indicate that not all marine mammal species have equal hearing 
capabilities (Richardson et al., 1995; Southall et al., 1997; Wartzok 
and Ketten, 1999; Au and Hastings, 2008).
    Southall et al. (2007) designated ``functional hearing groups'' for 
marine mammals based on available behavioral data; audiograms derived 
from auditory evoked potentials; anatomical modeling; and other data. 
Southall et al. (2007) also estimated the lower and upper frequencies 
of functional hearing for each group. However, animals are less 
sensitive to sounds at the outer edges of their functional hearing 
range and are more sensitive to a range of frequencies within the 
middle of their functional hearing range. Note that direct measurements 
of hearing sensitivity do not exist for all species of marine mammals, 
including low-frequency cetaceans. The functional hearing groups and 
the associated frequencies developed by Southall et al. (2007) were 
revised by Finneran and Jenkins (2012) and have been further modified 
by NOAA. Table 7 provides a summary of sound production and general 
hearing capabilities for marine mammal species (note that values in 
this table are not meant to reflect absolute possible maximum ranges, 
rather they represent the best known ranges of each functional hearing 
group). For purposes of the analysis in this proposed rule, marine 
mammals are arranged into the following functional hearing groups based 
on their generalized hearing sensitivities: High-frequency cetaceans, 
mid-frequency cetaceans, low-frequency cetaceans (mysticetes), phocids 
(true seals), otariids (sea lion and fur seals), and mustelids (sea 
otters). A detailed discussion of the functional hearing groups can be 
found in Southall et al. (2007) and Finneran and Jenkins (2012).

            Table 7--Marine Mammal Functional Hearing Groups
------------------------------------------------------------------------
      Functional hearing group            Functional hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen  7 Hz to 25 kHz.
 whales).
Mid-frequency (MF) cetaceans          150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true   200 Hz to 180 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (underwater) (true   75 Hz to 100 kHz.
 seals).
Otariid pinnipeds (underwater) (sea   100 Hz to 48 kHz.
 lions and fur seals).
------------------------------------------------------------------------
Adapted and derived from Southall et al. (2007)
* Represents frequency band of hearing for entire group as a composite
  (i.e., all species within the group), where individual species'
  hearing ranges are typically not as broad. Functional hearing is
  defined as the range of frequencies a group hears without
  incorporating non-acoustic mechanisms (Wartzok and Ketten, 1999). This
  is ~60 to ~70 dB above best hearing sensitivity (Southall et al.,
  2007) for all functional hearing groups except LF cetaceans, where no
  direct measurements on hearing are available. For LF cetaceans, the
  lower range is based on recommendations from Southall et al., 2007 and
  the upper range is based on information on inner ear anatomy and
  vocalizations.

    When sound travels (propagates) from its source, its loudness 
decreases as the distance traveled by the sound increases. Thus, the 
loudness of a sound at its source is higher than the loudness of that 
same sound a kilometer away. Acousticians often refer to the loudness 
of a sound at its source (typically referenced to one meter from the 
source) as the source level and the loudness of sound elsewhere as the 
received level (i.e., typically the receiver). For example, a humpback 
whale 3 km from a device that has a source level of 230 dB may only be 
exposed to sound that is 160 dB loud, depending on how the sound 
travels through water (e.g., spherical spreading [3 dB reduction with 
doubling of distance] was used in this example). As a result, it is 
important to understand the difference between source levels and 
received levels when discussing the loudness of sound in the ocean or 
its impacts on the marine environment.
    As sound travels from a source, its propagation in water is 
influenced by various physical characteristics, including water 
temperature, depth, salinity, and surface and bottom properties that 
cause refraction, reflection, absorption, and scattering of sound 
waves. Oceans are not homogeneous and the contribution of each of these 
individual factors is extremely complex and interrelated. The physical 
characteristics that determine the sound's speed through the water will 
change with depth, season, geographic location, and with time of day 
(as a result, in actual active sonar operations, crews will measure 
oceanic conditions, such as sea water temperature and depth, to 
calibrate models that determine the path the sonar signal will take as 
it travels through the ocean and how strong the sound signal will be at 
a given range along a particular transmission path). As sound travels 
through the ocean, the intensity associated with the wavefront 
diminishes, or attenuates. This decrease in intensity is referred to as 
propagation loss, also commonly called transmission loss.

Metrics Used in This Proposed Rule

    This section includes a brief explanation of the two sound 
measurements (sound pressure level (SPL) and sound exposure level 
(SEL)) frequently used to describe sound levels in the discussions of 
acoustic effects in this proposed rule.
    Sound pressure level (SPL)--Sound pressure is the sound force per 
unit area, and is usually measured in micropascals ([micro]Pa), where 1 
Pa is the pressure resulting from a force of one newton exerted over an 
area of one square meter. SPL is expressed as the

[[Page 9961]]

ratio of a measured sound pressure and a reference level.

SPL (in dB) = 20 log (pressure/reference pressure)

    The commonly used reference pressure level in underwater acoustics 
is 1 [micro]Pa, and the units for SPLs are dB re: 1 [micro]Pa. SPL is 
an instantaneous pressure measurement and can be expressed as the peak, 
the peak-peak, or the root mean square (rms). Root mean square 
pressure, which is the square root of the arithmetic average of the 
squared instantaneous pressure values, is typically used in discussions 
of the effects of sounds on vertebrates and all references to SPL in 
this proposed rule refer to the root mean square. SPL does not take the 
duration of exposure into account. SPL is the applicable metric used in 
the risk continuum, which is used to estimate behavioral harassment 
takes (see Level B Harassment Risk Function (Behavioral Harassment) 
Section).
    Sound exposure level (SEL)--SEL is an energy metric that integrates 
the squared instantaneous sound pressure over a stated time interval. 
The units for SEL are dB re: 1 [micro]Pa\2\-s. Below is a simplified 
formula for SEL.

SEL = SPL + 10log (duration in seconds)

    As applied to active sonar, the SEL includes both the SPL of a 
sonar ping and the total duration. Longer duration pings and/or pings 
with higher SPLs will have a higher SEL. If an animal is exposed to 
multiple pings, the SEL in each individual ping is summed to calculate 
the cumulative SEL. The cumulative SEL depends on the SPL, duration, 
and number of pings received. The thresholds that NMFS uses to indicate 
at what received level the onset of temporary threshold shift (TTS) and 
permanent threshold shift (PTS) in hearing are likely to occur are 
expressed as cumulative SEL.

Potential Effects of Specified Activities on Marine Mammals

    The Navy has requested authorization for the take of marine mammals 
that may occur incidental to training activities in the Study Area. The 
Navy has analyzed potential impacts to marine mammals from impulsive 
and non-impulsive sound sources.
    Other potential impacts to marine mammals from training activities 
in the Study Area were analyzed in the GOA DSEIS/OEIS, in consultation 
with NMFS as a cooperating agency, and determined to be unlikely to 
result in marine mammal harassment. Therefore, the Navy has not 
requested authorization for take of marine mammals that might occur 
incidental to other components of their proposed activities. In this 
proposed rule, NMFS analyzes the potential effects on marine mammals 
from exposure to non-impulsive sound sources (sonar and other active 
acoustic sources) and impulsive sound sources (underwater detonations).
    For the purpose of MMPA authorizations, NMFS' effects assessments 
serve four primary purposes: (1) To prescribe the permissible methods 
of taking (i.e., Level B harassment (behavioral harassment), Level A 
harassment (injury), or mortality, including an identification of the 
number and types of take that could occur by harassment or mortality) 
and to prescribe other means of effecting the least practicable adverse 
impact on such species or stock and its habitat (i.e., mitigation); (2) 
to determine whether the specified activity would have a negligible 
impact on the affected species or stocks of marine mammals (based on 
the likelihood that the activity would adversely affect the species or 
stock through effects on annual rates of recruitment or survival); (3) 
to determine whether the specified activity would have an unmitigable 
adverse impact on the availability of the species or stock(s) for 
subsistence uses; and (4) to prescribe requirements pertaining to 
monitoring and reporting.
    This section focuses qualitatively on the different ways that non-
impulsive and impulsive sources may affect marine mammals (some of 
which NMFS would not classify as harassment). Then the Estimated Take 
of Marine Mammals section discusses how the potential effects of non-
impulsive and impulsive sources on marine mammals will be related to 
the MMPA definitions of Level A and Level B Harassment, and attempts to 
quantify those effects.

Non-impulsive Sources

Direct Physiological Effects

    Based on the literature, there are two basic ways that non-
impulsive sources might directly result in physical trauma or damage: 
Noise-induced loss of hearing sensitivity (more commonly-called 
``threshold shift'') and acoustically mediated bubble growth. 
Separately, an animal's behavioral reaction to an acoustic exposure 
might lead to physiological effects that might ultimately lead to 
injury or death, which is discussed later in the Stranding section.
    Threshold Shift (noise-induced loss of hearing)--When animals 
exhibit reduced hearing sensitivity (i.e., sounds must be louder for an 
animal to detect them) following exposure to an intense sound or sound 
for long duration, it is referred to as a noise-induced threshold shift 
(TS). An animal can experience temporary threshold shift (TTS) or 
permanent threshold shift (PTS). TTS can last from minutes or hours to 
days (i.e., there is complete recovery), can occur in specific 
frequency ranges (i.e., an animal might only have a temporary loss of 
hearing sensitivity between the frequencies of 1 and 10 kHz), and can 
be of varying amounts (for example, an animal's hearing sensitivity 
might be reduced initially by only 6 dB or reduced by 30 dB). PTS is 
permanent, but some recovery is possible. PTS can also 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. As 
amplitude and duration of sound exposure increase, so, generally, does 
the amount of TS, along with the recovery time. For intermittent 
sounds, less TS could occur than compared to a continuous exposure with 
the same energy (some recovery could occur between intermittent 
exposures depending on the duty cycle between sounds) (Kryter et al., 
1966; Ward, 1997). For example, one short but loud (higher SPL) sound 
exposure may induce the same impairment as one longer but softer 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, prolonged exposure to sounds 
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). Although in the case of mid- and high-frequency 
active sonar (MFAS/HFAS), animals are not expected to be exposed to 
levels high enough or durations long enough to result in PTS.
    PTS is considered auditory injury (Southall et al., 2007). 
Irreparable damage to the inner or outer cochlear hair cells may cause 
PTS; however,

[[Page 9962]]

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. For 
marine mammals, published data are limited to the captive bottlenose 
dolphin, beluga, harbor porpoise, and Yangtze finless porpoise 
(Finneran et al., 2000, 2002b, 2003, 2005a, 2007, 2010a, 2010b; 
Finneran and Schlundt, 2010; Lucke et al., 2009; Mooney et al., 2009a, 
2009b; Popov et al., 2011a, 2011b; Kastelein et al., 2012a; Schlundt et 
al., 2000; Nachtigall et al., 2003, 2004). For pinnipeds in water, data 
are limited to measurements of TTS in harbor seals, an elephant seal, 
and California sea lions (Kastak et al., 1999, 2005; Kastelein et al., 
2012b).
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and 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 occurs 
during a time where ambient noise is lower and there are not as many 
competing sounds present. Alternatively, a larger amount and longer 
duration of TTS sustained during time when communication is critical 
for successful mother/calf interactions could have more serious 
impacts. Also, depending on the degree and frequency range, the effects 
of PTS on an animal could range in severity, although it is considered 
generally more serious because it is a permanent condition. Of note, 
reduced hearing sensitivity as a simple function of aging has been 
observed in marine mammals, as well as humans and other taxa (Southall 
et al., 2007), so one can infer that strategies exist for coping with 
this condition to some degree, though likely not without cost.
    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 (for example, beaked 
whales) are theoretically predicted to induce greater supersaturation 
(Houser et al., 2001b). If rectified diffusion were possible in marine 
mammals exposed to high-level sound, conditions of tissue 
supersaturation could theoretically speed the rate and increase the 
size of bubble growth. Subsequent effects due to tissue trauma and 
emboli would presumably mirror those observed in humans suffering from 
decompression sickness.
    It is unlikely that the short duration of sonar pings would be long 
enough to drive bubble growth to any substantial size, if such a 
phenomenon occurs. However, an alternative but related hypothesis has 
also been suggested: Stable bubbles could be destabilized by high-level 
sound exposures such that bubble growth then occurs through static 
diffusion of gas out of the tissues. In such a scenario the marine 
mammal would need to be in a gas-supersaturated state for a long enough 
period of time for bubbles to become of a problematic size. Recent 
research with ex vivo supersaturated bovine tissues suggested that, for 
a 37 kHz signal, a sound exposure of approximately 215 dB referenced to 
(re) 1 [mu]Pa would be required before microbubbles became destabilized 
and grew (Crum et al., 2005). Assuming spherical spreading loss and a 
nominal sonar source level of 235 dB re 1 [mu]Pa at 1 m, a whale would 
need to be within 10 m (33 ft.) of the sonar dome to be exposed to such 
sound levels. Furthermore, tissues in the study were supersaturated by 
exposing them to pressures of 400-700 kilopascals for periods of hours 
and then releasing them to ambient pressures. Assuming the 
equilibration of gases with the tissues occurred when the tissues were 
exposed to the high pressures, levels of supersaturation in the tissues 
could have been as high as 400-700 percent. These levels of tissue 
supersaturation are substantially higher than model predictions for 
marine mammals (Houser et al., 2001; Saunders et al., 2008). It is 
improbable that this mechanism is responsible for stranding events or 
traumas associated with beaked whale strandings. Both the degree of 
supersaturation and exposure levels observed to cause microbubble 
destabilization are unlikely to occur, either alone or in concert.
    Yet another hypothesis (decompression sickness) has speculated that 
rapid ascent to the surface following exposure to a startling sound 
might produce tissue gas saturation sufficient for the evolution of 
nitrogen bubbles (Jepson et al., 2003; Fernandez et al., 2005; 
Fern[aacute]ndez et al., 2012). In this scenario, the rate of ascent 
would need to be sufficiently rapid to compromise behavioral or 
physiological protections against nitrogen bubble formation. 
Alternatively, Tyack et al. (2006) studied the deep diving behavior of 
beaked whales and concluded that: ``Using current models of breath-hold 
diving, we infer that their natural diving behavior is inconsistent 
with known problems of acute nitrogen supersaturation and embolism.'' 
Collectively, these hypotheses can be referred to as ``hypotheses of 
acoustically mediated bubble growth.''
    Although theoretical predictions suggest the possibility for 
acoustically mediated bubble growth, there is considerable disagreement 
among scientists as to its likelihood (Piantadosi and Thalmann, 2004; 
Evans and Miller, 2003). 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). More recent work 
conducted by Crum et al. (2005) demonstrated the possibility of 
rectified diffusion for short duration signals, but at SELs and tissue 
saturation levels that are highly improbable to occur in diving marine 
mammals. To date, energy levels (ELs) predicted to cause in vivo bubble 
formation within diving cetaceans have not been evaluated (NOAA, 
2002b). Although it has been argued that traumas from some recent 
beaked whale strandings are consistent with gas emboli and bubble-
induced tissue separations (Jepson et al., 2003), there is no 
conclusive evidence of this. 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 sonar exposures. Further investigation is needed to 
further assess the potential

[[Page 9963]]

validity of these hypotheses. More information regarding hypotheses 
that attempt to explain how behavioral responses to non-impulsive 
sources can lead to strandings is included in the Stranding and 
Mortality section.

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 sounds in the environment 
are louder than and of a similar frequency to, auditory signals an 
animal is trying to receive. Masking is a phenomenon that affects 
animals that are 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 disturb 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, though, the detection of frequencies above those of 
the masking stimulus decreases also. This principle is expected to 
apply to marine mammals as well because of common biomechanical 
cochlear properties across taxa.
    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 low-frequency sound can mask 
high-frequency sounds (i.e., upward masking). Studies on captive 
odontocetes by Au et al. (1974, 1985, 1993) indicate that some species 
may use various processes to reduce masking effects (e.g., adjustments 
in echolocation call intensity or frequency as a function of background 
noise conditions). There is also evidence that the directional hearing 
abilities of odontocetes are useful in reducing masking at the high-
frequencies these cetaceans use to echolocate, but not at the low-to-
moderate frequencies they use to communicate (Zaitseva et al., 1980). A 
recent 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.
    The functional hearing ranges of mysticetes, odontocetes, and 
pinnipeds underwater all encompass the frequencies of the sonar sources 
used in the Navy's low-frequency (LF)/MFAS/HFAS training exercises. 
Additionally, almost all species' vocal repertoires span across the 
frequencies of these sonar sources used by the Navy. The closer the 
characteristics of the masking signal to the signal of interest, the 
more likely masking is to occur. For hull-mounted sonar, which accounts 
for a large number of the takes of marine mammals (because of the 
source strength and number of hours it is conducted), the pulse length 
and low duty cycle of the MFAS/HFAS signal makes it less likely that 
masking would occur as a result.

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 it drops to the 
level of ambient noise (Brenowitz, 2004; Brumm et al., 2004; Lohr et 
al., 2003). Animals are also aware of environmental conditions that 
affect whether listeners can discriminate and recognize their 
vocalizations from other sounds, which is more important than simply 
detecting that a vocalization is occurring (Brenowitz, 1982; Brumm et 
al., 2004; Dooling, 2004, Marten and Marler, 1977; Patricelli et al., 
2006). Most animals that vocalize have evolved with an ability to make 
adjustments to their vocalizations to increase the signal-to-noise 
ratio, active space, and recognizability/distinguishability of their 
vocalizations in the face of temporary changes in background noise 
(Brumm et al., 2004; Patricelli et al., 2006). Vocalizing animals can 
make adjustments to vocalization characteristics such as the frequency 
structure, amplitude, temporal structure, and temporal delivery.
    Many animals will combine several of these strategies to compensate 
for high levels of background noise. Anthropogenic sounds that reduce 
the signal-to-noise ratio of animal vocalizations, increase the masked 
auditory thresholds of animals listening for such vocalizations, or 
reduce the active space of an animal's vocalizations impair 
communication between animals. Most 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 remain 
unknown, like most other trade-offs animals must make, some of these 
strategies probably come at a cost (Patricelli et al., 2006). For 
example, 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). 
Shifting songs and calls to higher frequencies may also impose 
energetic costs (Lambrechts, 1996).

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 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.
    In the case of many stressors, an animal's first and sometimes most 
economical (in terms of biotic costs) response is behavioral avoidance 
of the potential stressor or avoidance of continued exposure to a 
stressor. An animal's second line of defense to stressors involves the 
sympathetic part of the autonomic nervous system and the classical 
``fight or flight'' response which includes the cardiovascular system, 
the gastrointestinal system, the exocrine glands, and the adrenal 
medulla to produce changes in heart rate, blood pressure, and 
gastrointestinal activity that humans commonly

[[Page 9964]]

associate with ``stress.'' These responses have a relatively short 
duration and may or may not have significant long-term effect on an 
animal's welfare.
    An animal's third line of defense to stressors involves its 
neuroendocrine systems; the system that has received the most study has 
been the hypothalmus-pituitary-adrenal system (also known as the HPA 
axis in mammals or the hypothalamus-pituitary-interrenal axis in fish 
and some reptiles). Unlike stress responses associated with the 
autonomic nervous system, virtually all neuro-endocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction (Moberg, 1987; Rivier, 1995), altered 
metabolism (Elasser et al., 2000), reduced immune competence (Blecha, 
2000), and behavioral disturbance. 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 function, 
which impairs those functions that experience the diversion. For 
example, when mounting a stress response diverts energy away from 
growth in young animals, those animals may experience stunted growth. 
When mounting a stress response diverts energy from a fetus, an 
animal's reproductive success and its fitness will suffer. In these 
cases, the animals will have entered a pre-pathological or pathological 
state which is called ``distress'' (Seyle, 1950) or ``allostatic 
loading'' (McEwen and Wingfield, 2003). This pathological state will 
last until the animal replenishes its biotic reserves sufficient to 
restore normal function. Note that these examples involved a long-term 
(days or weeks) stress response exposure to stimuli.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses 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; Reneerkens et al., 2002; Thompson and Hamer, 
2000). Information has also been collected on the physiological 
responses of marine mammals to exposure to anthropogenic sounds (Fair 
and Becker, 2000; Romano et al., 2002; Wright et al., 2008). Various 
efforts have been undertaken to investigate the impact from vessels 
(both whale-watching and general vessel traffic noise), and 
demonstrated impacts do occur (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 
training activities in the GOA TMAA. For example, in an analysis of 
energy costs to killer whales, Williams et al. (2009) suggested that 
whale-watching in Canada's Johnstone Strait resulted in lost feeding 
opportunities due to vessel disturbance, which could carry higher costs 
than other measures of behavioral change might suggest. Ayres et al. 
(2012) recently reported on research in the Salish Sea (Washington 
state) involving the measurement of southern resident killer whale 
fecal hormones to assess two potential threats to the species recovery: 
Lack of prey (salmon) and impacts to behavior from vessel traffic. 
Ayres et al. (2012) suggested that the lack of prey overshadowed any 
population-level physiological impacts on southern resident killer 
whales from vessel traffic. 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. 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).
    Studies of other marine animals and terrestrial animals would also 
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 high frequency, mid-
frequency and low-frequency sounds. For example, Jansen (1998) reported 
on the relationship between acoustic exposures and physiological 
responses that are indicative of stress responses in humans (for 
example, 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 physiological stress responses of endangered Sonoran pronghorn to 
military overflights. Smith et al. (2004a, 2004b), for example, 
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 to communicate with 
conspecifics. Although empirical information on the relationship 
between sensory impairment (TTS, PTS, and acoustic masking) on marine 
mammals remains limited, it seems reasonable to assume that reducing an 
animal's ability to gather information about its environment and to 
communicate with other members of its species would be stressful for 
animals that use hearing as their primary sensory mechanism. Therefore, 
we assume that acoustic exposures sufficient to trigger onset PTS or 
TTS would be accompanied by physiological stress responses because 
terrestrial animals exhibit those responses under similar conditions 
(NRC, 2003). More importantly, marine mammals might experience stress 
responses at received levels lower than those necessary to trigger 
onset TTS. Based on empirical studies of the time required to recover 
from stress responses (Moberg, 2000), we also assume that stress 
responses are likely to persist beyond the time interval required for 
animals to recover from TTS and might result in pathological and pre-
pathological states that would

[[Page 9965]]

be as significant as behavioral responses to TTS.

Behavioral Disturbance

    Behavioral responses to sound are highly variable and context-
specific. Many different variables can influence an animal's perception 
of and response to (nature and magnitude) an acoustic event. An 
animal's prior experience with a sound or sound source affects whether 
it is less likely (habituation) or more likely (sensitization) to 
respond to certain sounds in the future (animals 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 
a sound to biologically relevant sounds in the animal's environment 
(i.e., calls of predators, prey, or conspecifics), and familiarity of 
the sound may affect the way an animal responds to the sound (Southall 
et al., 2007). 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. 
Ellison et al. (2012) outlined an approach to assessing the effects of 
sound on marine mammals that incorporates contextual-based factors. 
They recommend considering not just the received level of sound, but 
also the activity the animal is engaged in at the time the sound is 
received, the nature and novelty of the sound (i.e., is this a new 
sound from the animal's perspective), and the distance between the 
sound source and the animal. They submit that this ``exposure 
context,'' as described, greatly influences the type of behavioral 
response exhibited by the animal. This sort of contextual information 
is challenging to predict with accuracy for ongoing activities that 
occur over large scales and large periods of time. While contextual 
elements of this sort are typically not included in calculations to 
quantify take, they are often considered qualitatively (where 
supporting information is available) in the subsequent analysis that 
seeks to assess the likely consequences of sound exposures above a 
certain level.
    Exposure of marine mammals to sound sources can result in no 
response or responses including, but not limited to: Increased 
alertness; orientation or attraction to a sound source; vocal 
modifications; cessation of feeding; cessation of social interaction; 
alteration of movement or diving behavior; habitat abandonment 
(temporary or permanent); and, in severe cases, panic, flight, 
stampede, or stranding, potentially resulting in death (Southall et 
al., 2007). A review of marine mammal responses to anthropogenic sound 
was first conducted by Richardson and others in 1995. More recent 
reviews (Nowacek et al., 2007; Ellison et al., 2012) address studies 
conducted since 1995 and focuses on observations where the received 
sound level of the exposed marine mammal(s) was known or could be 
estimated. The following sub-sections provide examples of behavioral 
responses that provide an idea of the variability in behavioral 
responses that would be expected given the differential sensitivities 
of marine mammal species to sound and the wide range of potential 
acoustic sources to which a marine mammal may be exposed. Estimates of 
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.
    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 presence of predators have 
occurred (Connor and Heithaus, 1996). Flight responses have been 
speculated as being a component of marine mammal strandings associated 
with sonar activities (Evans and England, 2001).
    Response to Predator--Evidence suggests that at least some marine 
mammals have the ability to acoustically identify potential predators. 
For example, harbor seals that reside in the coastal waters off British 
Columbia are frequently targeted by certain groups of killer whales, 
but not others. The seals discriminate between the calls of threatening 
and non-threatening killer whales (Deecke et al., 2002), a capability 
that should increase survivorship while reducing the energy required 
for attending to and responding to all killer whale calls. The 
occurrence of masking or hearing impairment provides a means by which 
marine mammals may be prevented from responding to the acoustic cues 
produced by their predators. Whether or not this is a possibility 
depends on the duration of the masking/hearing impairment and the 
likelihood of encountering a predator during the time that predator 
cues are impeded.
    Diving--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 exposure depends on what the animal is doing at the time of 
the exposure and the type and magnitude of the response.
    Nowacek et al. (2004) reported disruptions of dive behaviors in 
foraging North Atlantic right whales when exposed to an alerting 
stimulus, an action, they noted, that could lead to an increased 
likelihood of ship strike. However, the whales did not respond to 
playbacks of either right whale social sounds or vessel noise, 
highlighting the importance of the sound characteristics in producing a 
behavioral reaction. Conversely, Indo-Pacific humpback dolphins have 
been observed to dive for longer periods of time in areas where vessels 
were present and/or approaching (Ng and Leung, 2003). In both of these 
studies, the influence of the sound exposure cannot be decoupled from 
the physical presence of a surface vessel, thus complicating 
interpretations of the relative contribution of each stimulus to the 
response. Indeed, the presence of surface vessels, their approach, and 
speed of approach, seemed to be significant factors in the response of 
the Indo-Pacific humpback dolphins (Ng and Leung, 2003). Low frequency 
signals of the Acoustic Thermometry of Ocean Climate (ATOC) sound 
source were not found to affect dive times of humpback whales in 
Hawaiian waters (Frankel and Clark, 2000) or to overtly affect elephant 
seal dives (Costa et al., 2003). They did, however, produce subtle 
effects that varied in direction and degree among the individual seals, 
illustrating the equivocal nature of behavioral effects and consequent

[[Page 9966]]

difficulty in defining and predicting them.
    Due to past incidents of beaked whale strandings associated with 
sonar operations, feedback paths are provided between avoidance and 
diving and indirect tissue effects. This feedback accounts for the 
hypothesis that variations in diving behavior and/or avoidance 
responses can possibly result in nitrogen tissue supersaturation and 
nitrogen off-gassing, possibly to the point of deleterious vascular 
bubble formation (Jepson et al., 2003). Although hypothetical, 
discussions surrounding this potential process are controversial.
    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 in western grey 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). However, Miller et al. (2009) reported buzz 
rates (a proxy for feeding) 19 percent lower during exposure to distant 
signatures of seismic airguns. Balaenopterid whales exposed to moderate 
low-frequency signals similar to the ATOC sound source demonstrated no 
variation in foraging activity (Croll et al., 2001), whereas five out 
of six North Atlantic right whales exposed to an acoustic alarm 
interrupted their foraging dives (Nowacek et al., 2004). Although the 
received sound pressure levels were similar in the latter two studies, 
the frequency, duration, and temporal pattern of signal presentation 
were different. These factors, as well as differences in species 
sensitivity, are likely contributing factors to the differential 
response. Blue whales exposed to 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, Melcon et al. (2012) were unable to determine if 
suppression of low frequency calls reflected a change in their feeding 
performance or abandonment of foraging behavior and indicated that 
implications of the documented responses are unknown. Further, it is 
not known whether the lower rates of calling actually indicated a 
reduction in feeding behavior or social contact since the study used 
data from remotely deployed, passive acoustic monitoring buoys. In 
contrast, blue whales increased their likelihood of calling when ship 
noise was present, and decreased their likelihood of calling in the 
presence of explosive noise, although this result was not statistically 
significant (Melc[oacute]n et al., 2012). Additionally, the likelihood 
of an animal calling decreased with the increased received level of 
mid-frequency sonar, beginning at a SPL of approximately 110-120 dB re 
1 [mu]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., 2012b). 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. Goldbogen 
et al., (2013) monitored behavioral responses of tagged blue whales 
located in feeding areas when exposed 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, particularly since unconsumed prey would 
likely still be available in the environment in most cases following 
the cessation of acoustic exposure.
    Breathing--Variations in respiration naturally vary with different 
behaviors and variations in respiration rate as a function of acoustic 
exposure can be expected to co-occur with other behavioral reactions, 
such as a flight response or an alteration in diving. However, 
respiration rates in and of themselves may be representative of 
annoyance or an acute stress response. Mean exhalation rates of gray 
whales at rest and while diving were found to be unaffected by seismic 
surveys conducted adjacent to the whale feeding grounds (Gailey et al., 
2007). Studies with captive harbor porpoises showed increased 
respiration rates upon introduction of acoustic alarms (Kastelein et 
al., 2001; Kastelein et al., 2006a) and emissions for underwater data 
transmission (Kastelein et al., 2005). However, exposure of the same 
acoustic alarm to a striped dolphin under the same conditions did not 
elicit a response (Kastelein et al., 2006a), again highlighting the 
importance in understanding species differences in the tolerance of 
underwater noise when determining the potential for impacts resulting 
from anthropogenic sound exposure.
    Social Relationships--Social interactions between mammals can be 
affected by noise via the disruption of communication signals or by the 
displacement of individuals. Disruption of social relationships 
therefore depends on the disruption of other behaviors (e.g., caused 
avoidance, masking, etc.) and no specific overview is provided here. 
However, social disruptions must be considered in context of the 
relationships that are affected. Long-term disruptions of mother/calf 
pairs or mating displays have the potential to affect the growth and 
survival or reproductive effort/success of individuals, respectively.
    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., 
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; Roland et al., 2012). Killer whales off the 
northwestern coast of the U.S. have been observed to increase the 
duration of primary calls once a threshold in

[[Page 9967]]

observing vessel density (e.g., whale watching) was reached, which has 
been suggested as a response to increased masking noise produced by the 
vessels (Foote et al., 2004; NOAA, 2014b). 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. It 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. 
Longer term displacement is possible, however, which can lead to 
changes in abundance or distribution patterns of the species in the 
affected region if they do not become acclimated to the presence of the 
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 longer term or 
repetitive/chronic displacement for some dolphin groups and for 
manatees has been suggested to be due to the presence of chronic vessel 
noise (Haviland-Howell et al., 2007; Miksis-Olds et al., 2007).
    Maybaum (1993) conducted sound playback experiments to assess the 
effects of MFAS on humpback whales in Hawaiian waters. Specifically, 
she exposed focal pods to sounds of a 3.3-kHz sonar pulse, a sonar 
frequency sweep from 3.1 to 3.6 kHz, and a control (blank) tape while 
monitoring behavior, movement, and underwater vocalizations. The two 
types of sonar signals (which both contained mid- and low-frequency 
components) differed in their effects on the humpback whales, but both 
resulted in avoidance behavior. The whales responded to the pulse by 
increasing their distance from the sound source and responded to the 
frequency sweep by increasing their swimming speeds and track 
linearity. In the Caribbean, sperm whales avoided exposure to mid-
frequency submarine sonar pulses, in the range of 1000 Hz to 10,000 Hz 
(IWC 2005).
    Kvadsheim et al. (2007) conducted a controlled exposure experiment 
in which killer whales fitted with D-tags were exposed to mid-frequency 
active sonar (Source A: A 1.0 second upsweep 209 dB @ 1-2 kHz every 10 
seconds for 10 minutes; Source B: With a 1.0 second upsweep 197 dB @ 6-
7 kHz every 10 seconds for 10 minutes). When exposed to Source A, a 
tagged whale and the group it was traveling with did not appear to 
avoid the source. When exposed to Source B, the tagged whales along 
with other whales that had been carousel feeding, 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 
killer whales were consistent with the results of other studies.
    In 2007, the first in a series of behavioral response studies, a 
collaboration by the Navy, NMFS, and other scientists showed one beaked 
whale (Mesoplodon densirostris) responding to an MFAS playback. Tyack 
et al. (2011) indicates that the playback began when the tagged beaked 
whale was vocalizing at depth (at the deepest part of a typical feeding 
dive), following a previous control with no sound exposure. The whale 
appeared to stop clicking significantly earlier than usual, when 
exposed to 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 indicates that Blainville's beaked whales 
appear to be sensitive to noise at levels well below expected TTS (~160 
dB re1[mu]Pa). This sensitivity is manifest by an adaptive movement 
away from a sound source. This response was observed irrespective of 
whether the signal transmitted was within the band width of MFAS, which 
suggests that beaked whales may not respond to the specific sound 
signatures. Instead, they may be sensitive to any pulsed sound from a 
point source in this frequency range. The response to such stimuli 
appears to involve maximizing the distance from the sound source.
    Stimpert et al. (2014) tagged a Baird's beaked whale, which was 
subsequently exposed to simulated MFAS. Received levels of sonar on the 
tag increased to a maximum of 138 dB re 1[mu]Pa, which occurred during 
the first exposure dive. Some sonar received levels could not be 
measured due to flow noise and surface noise on the tag.
    Results from a 2007-2008 study conducted near the Bahamas showed a 
change in diving behavior of an adult Blainville's beaked whale to 
playback of MFAS and predator sounds (Boyd et al., 2008; Southall et 
al. 2009; Tyack et al., 2011). Reaction to mid-frequency sounds 
included premature cessation of clicking and termination of a foraging 
dive, and a slower ascent rate to the surface. Results from a similar 
behavioral response study in southern California waters have been 
presented for the 2010-2011 field season (Southall et al. 2011; 
DeRuiter et al., 2013b). DeRuiter et al. (2013b) presented results from 
two Cuvier's beaked whales that were tagged and exposed to simulated 
MFAS during the 2010 and 2011 field seasons of the southern California 
behavioral response study. The 2011 whale was also incidentally exposed 
to MFAS from a distant naval exercise. Received levels from the MFAS 
signals from the controlled and incidental exposures were calculated as 
84-144 and 78-106 dB re 1 [mu]Pa root mean square (rms), respectively. 
Both whales showed responses to the controlled exposures, ranging from 
initial orientation changes to avoidance responses characterized by 
energetic fluking and swimming away from the source. However, the 
authors did not detect similar responses to incidental exposure to 
distant naval sonar exercises at comparable received levels, indicating 
that context of the exposures (e.g., source proximity, controlled 
source ramp-up) may have been a significant factor. Specifically, this 
result suggests that caution is needed when using marine mammal 
response data collected from smaller, nearer sound sources to predict 
at what

[[Page 9968]]

received levels animals may repond to larger sound sources that are 
significantly farther away--as the distance of the source appears to be 
an important contextual variable and animals may be less responsive to 
sources at notably greater distances. Cuvier's beaked whale responses 
suggested particular sensitivity to sound exposure as consistent with 
results for Blainville's beaked whale. Similarly, beaked whales exposed 
to sonar during British training exercises stopped foraging (DSTL, 
2007), and preliminary results of controlled playback of sonar may 
indicate feeding/foraging disruption of killer whales and sperm whales 
(Miller et al., 2011).
    In the 2007-2008 Bahamas study, playback sounds of a potential 
predator--a killer whale--resulted in a similar but more pronounced 
reaction, which included longer inter-dive intervals and a sustained 
straight-line departure of more than 20 km from the area (Boyd et al., 
2008; Southall et al. 2009; Tyack et al., 2011). The authors noted, 
however, that the magnified reaction to the predator sounds could 
represent a cumulative effect of exposure to the two sound types since 
killer whale playback began approximately 2 hours after mid-frequency 
source playback. Pilot whales and killer whales off Norway also 
exhibited horizontal avoidance of a transducer with outputs in the mid-
frequency range (signals in the 1-2 kHz and 6-7 kHz ranges) (Miller et 
al., 2011). Additionally, separation of a calf from its group during 
exposure to MFAS playback was observed on one occasion (Miller et al., 
2011; 2012). Miller et al. (2012) noted that this single observed 
mother-calf separation was unusual for several reasons, including the 
fact that the experiment was conducted in an unusually narrow fjord 
roughly 1 km wide and that the sonar exposure was started unusually 
close to the pod including the calf. Both of these factors could have 
contributed to calf separation. In contrast, preliminary analyses 
suggest that none of the pilot whales or false killer whales in the 
Bahamas showed an avoidance response to controlled exposure playbacks 
(Southall et al., 2009).
    Through analysis of the behavioral response studies, a preliminary 
overarching effect of greater sensitivity to all anthropogenic 
exposures was seen in beaked whales compared to the other odontocetes 
studied (Southall et al., 2009). Therefore, recent studies have focused 
specifically on beaked whale responses to active sonar transmissions or 
controlled exposure playback of simulated sonar on various military 
ranges (Defence Science and Technology Laboratory, 2007; Claridge and 
Durban, 2009; Moretti et al., 2009; McCarthy et al., 2011; Miller et 
al., 2012; Southall et al., 2011, 2012a, 2012b, 2013, 2014; Tyack et 
al., 2011). In the Bahamas, Blainville's beaked whales located on the 
range will move off-range during sonar use and return only after the 
sonar transmissions have stopped, sometimes taking several days to do 
so (Claridge and Durban 2009; Moretti et al., 2009; McCarthy et al., 
2011; Tyack et al., 2011). Moretti et al. (2014) used recordings from 
seafloor-mounted hydrophones at the Atlantic Undersea Test and 
Evaluation Center (AUTEC) to analyze the probability of Blainsville's 
beaked whale dives before, during, and after Navy sonar exercises.
    Orientation--A shift in an animal's resting state or an attentional 
change via an orienting response represent behaviors that would be 
considered mild disruptions if occurring alone. As previously 
mentioned, the responses may co-occur with other behaviors; for 
instance, an animal may initially orient toward a sound source, and 
then move away from it. Thus, any orienting response should be 
considered in context of other reactions that may occur.

Behavioral Responses

    Southall et al. (2007) reports the results of the efforts of a 
panel of experts in acoustic research from behavioral, physiological, 
and physical disciplines that convened and 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 were 
not included in the quantitative analysis for the criteria 
recommendations. All of the studies considered, however, contain an 
estimate of the received sound level when the animal exhibited the 
indicated response.
    In the Southall et al. (2007) publication, for the purposes of 
analyzing responses of marine mammals to anthropogenic sound and 
developing criteria, the authors differentiate between single pulse 
sounds, multiple pulse sounds, and non-pulse sounds. MFAS/HFAS sonar is 
considered a non-pulse sound. Southall et al. (2007) summarize the 
studies associated with low-frequency, mid-frequency, and high-
frequency cetacean and pinniped responses to non-pulse sounds, based 
strictly on received level, in Appendix C of their article 
(incorporated by reference and summarized in the three paragraphs 
below).
    The studies that address responses of low-frequency cetaceans to 
non-pulse sounds include data gathered in the field and related to 
several types of sound sources (of varying similarity to MFAS/HFAS) 
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 range. As mentioned earlier, though, contextual variables 
play a very important role in the reported responses and the severity 
of effects are not linear when compared to received level. Also, few of 
the laboratory or field datasets had common conditions, behavioral 
contexts or sound sources, so it is not surprising that responses 
differ.
    The studies that address responses of mid-frequency cetaceans to 
non-pulse sounds include data gathered both in the field and the 
laboratory and related to several different sound sources (of varying 
similarity to MFAS/HFAS) including: Pingers, drilling playbacks, ship 
and ice-breaking noise, vessel noise, Acoustic Harassment Devices 
(AHDs), Acoustic Deterrent Devices (ADDs), MFAS, and non-pulse bands 
and tones. Southall et al. (2007) were unable to come to a clear 
conclusion regarding the results of these studies. In some cases, 
animals in the field showed significant responses to received levels 
between 90 and 120 dB, while in other cases these responses were not 
seen in the 120 to 150 dB range. The disparity in results was likely 
due to contextual variation and the differences between the results in 
the field and laboratory data (animals typically responded at lower 
levels in the field).
    The studies that address responses of high-frequency cetaceans to 
non-pulse sounds include data gathered both in the field and the 
laboratory and related to several different sound sources (of varying 
similarity to MFAS/HFAS) including: Pingers, AHDs, and various 
laboratory non-pulse sounds. All of these data were collected from 
harbor

[[Page 9969]]

porpoises. Southall et al. (2007) concluded that the existing data 
indicate that harbor porpoises are likely sensitive to a wide range of 
anthropogenic sounds at low received levels (~ 90 to 120 dB), at least 
for initial exposures. All recorded exposures above 140 dB 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 is no data to indicate whether other high frequency 
cetaceans are as sensitive to anthropogenic sound as harbor porpoises.
    The studies that address the responses of pinnipeds in water to 
non-impulsive sounds include data gathered both in the field and the 
laboratory and related to several different sound sources (of varying 
similarity to MFAS/HFAS) 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 the analysis. The limited data suggested that exposures 
to non-pulse sounds between 90 and 140 dB generally do not result in 
strong behavioral responses in 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 well-being (survival, reproduction, etc.) of 
an animal. There is limited marine mammal data quantitatively relating 
the exposure of marine mammals to sound to effects on reproduction or 
survival, though data exists for terrestrial species to which we can 
draw comparisons for marine mammals.
    Attention is the cognitive process of selectively concentrating on 
one aspect of an animal's environment while ignoring other things 
(Posner, 1994). Because animals (including humans) have limited 
cognitive resources, there is a limit to how much sensory information 
they can process at any time. The phenomenon called ``attentional 
capture'' occurs when a stimulus (usually a stimulus that an animal is 
not concentrating on or attending to) ``captures'' an animal's 
attention. This shift in attention can occur consciously or 
subconsciously (for example, when an animal hears sounds that it 
associates with the approach of a predator) and the shift in attention 
can be sudden (Dukas, 2002; van Rij, 2007). Once a stimulus has 
captured an animal's attention, the animal can respond by ignoring the 
stimulus, assuming a ``watch and wait'' posture, or treat the stimulus 
as a disturbance and respond accordingly, which includes scanning for 
the source of the stimulus or ``vigilance'' (Cowlishaw et al., 2004).
    Vigilance is normally an adaptive behavior that helps animals 
determine the presence or absence of predators, assess their distance 
from conspecifics, or to attend cues from prey (Bednekoff and Lima, 
1998; Treves, 2000). Despite those benefits, however, vigilance has a 
cost of time; when animals focus their attention on specific 
environmental cues, they are not attending to other activities such as 
foraging. 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 
(for example, multiple surface vessels), or when they co-occur with 
times that an animal perceives increased risk (for example, when they 
are giving birth or accompanied by a calf). Most of the published 
literature, however, suggests that direct approaches will increase the 
amount of time animals will dedicate to being vigilant. For example, 
bighorn sheep and Dall's sheep dedicated more time being vigilant, and 
less time resting or foraging, when aircraft made direct approaches 
over them (Frid, 2001; Stockwell et al., 1991).
    Several authors have established that long-term and intense 
disturbance stimuli can cause population declines by reducing the body 
condition of individuals that have been disturbed, followed by reduced 
reproductive success, reduced survival, or both (Daan et al., 1996; 
Madsen, 1994; White, 1983). For example, Madsen (1994) reported that 
pink-footed geese in undisturbed habitat gained body mass and had about 
a 46-percent reproductive success rate compared with geese in disturbed 
habitat (being consistently scared off the fields on which they were 
foraging) which did not gain mass and had a 17-percent reproductive 
success rate. Similar reductions in reproductive success have been 
reported for mule deer disturbed by all-terrain vehicles (Yarmoloy et 
al., 1988), caribou disturbed by seismic exploration blasts (Bradshaw 
et al., 1998), caribou disturbed by low-elevation military jet-fights 
(Luick et al., 1996), and caribou disturbed by low-elevation jet 
flights (Harrington and Veitch, 1992). Similarly, a study of elk 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 and, as a result, reducing the time they might 
spend foraging and resting (which increases an animal's activity rate 
and energy demand). For example, a study of grizzly bears reported that 
bears disturbed by hikers reduced their energy intake by an average of 
12 kcal/minute (50.2 x 10\3\kJ/minute), and spent energy fleeing or 
acting aggressively toward hikers (White et al. 1999). Alternately, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a 5-day period did not cause any sleep 
deprivation or stress effects such as changes in cortisol or 
epinephrine levels.
    Lusseau and Bejder (2007) present data from three long-term studies 
illustrating the connections between disturbance from whale-watching 
boats and population-level effects in cetaceans. In Sharks Bay 
Australia, the abundance of bottlenose dolphins was compared within 
adjacent control and tourism sites over three consecutive 4.5-year 
periods of increasing tourism levels. Between the second and third time 
periods, in which tourism doubled, dolphin abundance decreased by 15 
percent in the tourism area and did not change significantly in the 
control area. In Fiordland, New Zealand, two populations (Milford and 
Doubtful Sounds) of bottlenose dolphins with tourism levels that 
differed by a factor of seven were observed and significant increases 
in travelling time and decreases in resting time were documented for 
both. Consistent short-term avoidance strategies were observed in 
response to tour boats until a threshold of disturbance was reached 
(average 68 minutes between interactions), after which the response 
switched to a longer term habitat displacement strategy. For one 
population tourism only occurred in a part of the home range, however, 
tourism occurred throughout the home range of the Doubtful Sound 
population and once boat traffic increased beyond the 68-minute 
threshold (resulting in abandonment of their home range/preferred 
habitat), reproductive success drastically decreased (increased

[[Page 9970]]

stillbirths) and abundance decreased significantly (from 67 to 56 
individuals in short period). Last, in a study of northern resident 
killer whales off Vancouver Island, exposure to boat traffic was shown 
to reduce foraging opportunities and increase traveling time. A simple 
bioenergetics model was applied to show that the reduced foraging 
opportunities equated to a decreased energy intake of 18 percent, while 
the increased traveling incurred an increased energy output of 3-4 
percent, which suggests that a management action based on avoiding 
interference with foraging might be particularly effective.
    On a related note, many animals perform vital functions, such as 
feeding, resting, traveling, and socializing, on a diel cycle (24-hour 
cycle). Substantive behavioral reactions to noise exposure (such as 
disruption of critical life functions, displacement, or avoidance of 
important habitat) are more likely to be significant if they last more 
than one diel cycle or recur on subsequent days (Southall et al., 
2007). Consequently, a behavioral response lasting less than 1 day and 
not recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multiple-day 
substantive behavioral reactions and multiple-day anthropogenic 
activities. For example, just because an at-sea exercises last for 
multiple days does not necessarily mean that individual animals are 
either exposed to those exercises for multiple days or, further, 
exposed in a manner resulting in a sustained multiple day substantive 
behavioral responses.
    In order to understand how the effects of activities may or may not 
impact stocks and populations of marine mammals, it is necessary to 
understand not only what the likely disturbances are going to be, but 
how those disturbances may affect the reproductive success and 
survivorship of individuals, and then how those impacts to individuals 
translate to population changes. Following on the earlier work of a 
committee of the U.S. National Research Council (NRC, 2005), New et al. 
(2014), in an effort termed the Potential Consequences of Disturbance 
(PCoD), outline an updated conceptual model of the relationships 
linking disturbance to changes in behavior and physiology, health, 
vital rates, and population dynamics (below). As depicted, behavioral 
and physiological changes can either 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, or 
they can have indirect and long-term (chronic) effects on vital rates, 
such as when changes in time/energy budgets or increased disease 
susceptibility affect health, which then affects vital rates (New et 
al., 2014). In addition to outlining this general framework and 
compiling the relevant literature that supports it, New et al. (2014) 
have chosen 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 from behavioral changes. While 
these are very specific models with very specific data requirements 
that cannot yet be applied broadly to project-specific risk 
assessments, they are a critical first step.

Stranding and Mortality

    When a live or dead marine mammal swims or floats onto shore and 
becomes ``beached'' or incapable of returning to sea, the event is 
termed a ``stranding'' (Geraci et al., 1999; Perrin and Geraci, 2002; 
Geraci and Lounsbury, 2005; NMFS, 2007). The legal definition for a 
stranding within the U.S. can be found in section 410 of the MMPA (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; DeVries et al., 2003; 
Fair and Becker, 2000; Foley et al., 2001; Moberg, 2000; Relyea, 2005a; 
2005b, Romero, 2004; Sih et al., 2004). For reference, between 2001 and 
2009, there was an annual average of 1,400 cetacean strandings and 
4,300 pinniped strandings along the coasts of the continental U.S. and 
Alaska (NMFS, 2011).
    Several sources have published lists of mass stranding events of 
cetaceans in an attempt to identify relationships between those 
stranding events and military 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) identified ten mass stranding events of Cuvier's beaked whales 
had been reported and one mass stranding of four Baird's beaked whale. 
The IWC concluded that, out of eight stranding events reported from the 
mid-1980s to the summer of 2003, seven had been coincident with the use 
of tactical mid-frequency sonar, one of those seven had been associated 
with the use of tactical low-frequency sonar, and the remaining 
stranding event had been associated with the use of seismic airguns.
    Most of the stranding events reviewed by the International Whaling 
Commission involved beaked whales. A mass stranding of Cuvier's beaked 
whales in the eastern Mediterranean Sea occurred in 1996 (Frantzis, 
1998) and mass stranding events involving Gervais' beaked whales, 
Blainville's beaked whales, and Cuvier's beaked whales occurred off the 
coast of the Canary Islands in the late 1980s (Simmonds and Lopez-
Jurado, 1991). The stranding events that occurred in the Canary Islands 
and Kyparissiakos Gulf in the late 1990s and the Bahamas in 2000 have 
been the most intensively-studied mass stranding events and have been 
associated with naval maneuvers involving the use of tactical sonar.
    Between 1960 and 2006, 48 strandings (68 percent) involved beaked 
whales, three (4 percent) involved dolphins, and 14 (20 percent) 
involved whale species. Cuvier's beaked whales were involved in the 
greatest number of these events (48 or 68 percent), followed by sperm 
whales (seven or 10 percent), and Blainville's and Gervais' beaked 
whales (four each or 6 percent). Naval activities (not just activities 
conducted by the U.S. Navy) that might have involved active sonar are 
reported to have coincided with nine or 10 (13 to 14 percent) of those 
stranding events. Between the mid-1980s and 2003 (the period reported 
by the International Whaling Commission), NMFS identified reports of 44 
mass cetacean stranding events of which at least seven were coincident 
with naval exercises that were using MFAS.

[[Page 9971]]

Strandings Associated With Impulsive Sound

    Silver Strand--During a Navy training event on March 4, 2011 at the 
Silver Strand Training Complex in San Diego, California, three or 
possibly four dolphins were killed in an explosion. During an 
underwater detonation training event, a pod of 100 to 150 long-beaked 
common dolphins were observed moving towards the 700-yd (640.1-m) 
exclusion zone around the explosive charge, monitored by personnel in a 
safety boat and participants in a dive boat. Approximately 5 minutes 
remained on a time-delay fuse connected to a single 8.76 lb (3.97 kg) 
explosive charge (C-4 and detonation cord). Although the dive boat was 
placed between the pod and the explosive in an effort to guide the 
dolphins away from the area, that effort was unsuccessful and three 
long-beaked common dolphins near the explosion died. In addition to the 
three dolphins found dead on March 4, the remains of a fourth dolphin 
were discovered on March 7, 2011 near Ocean Beach, California (3 days 
later and approximately 11.8 mi. [19 km] from Silver Strand where the 
training event occurred), which might also have been related to this 
event. Association of the fourth stranding with the training event is 
uncertain because dolphins strand on a regular basis in the San Diego 
area. Details such as the dolphins' depth and distance from the 
explosive at the time of the detonation could not be estimated from the 
250 yd (228.6 m) standoff point of the observers in the dive boat or 
the safety boat.
    These dolphin mortalities are the only known occurrence of a U.S. 
Navy training or testing event involving impulsive energy (underwater 
detonation) that caused mortality or injury to a marine mammal (of 
note, the time-delay firing underwater explosive training activity 
implicated in the March 4 incident is not proposed for the training 
activities in the GOA Study Area). Despite this being a rare 
occurrence, the Navy has reviewed training requirements, safety 
procedures, and possible mitigation measures and implemented changes to 
reduce the potential for this to occur in the future. Discussions of 
procedures associated with underwater explosives training and other 
training events are presented in the Proposed Mitigation section.
    Kyle of Durness, Scotland--On July 22, 2011 a mass stranding event 
involving long-finned pilot whales occurred at Kyle of Durness, 
Scotland. An investigation by Brownlow et al. (2015) considered 
unexploded ordnance detonation activities at a Ministry of Defense 
bombing range, conducted by the Royal Navy prior to and during the 
strandings, as a plausible contributing factor in the mass stranding 
event. While Brownlow et al. (2015) concluded that the serial 
detonations of underwater ordnance were an influential factor in the 
mass stranding event (along with presence of a potentially compromised 
animal and navigational error in a topographically complex region) they 
also suggest that mitigation measures--which included observations from 
a zodiac only and by personnel not experienced in marine mammal 
observation, among other deficiencies--were likely insufficient to 
assess if cetaceans were in the vicinity of the detonations. The 
authors also cite information from the Ministry of Defense indicating 
``an extraordinarily high level of activity'' (i.e., frequency and 
intensity of underwater explosions) on the range in the days leading up 
to the stranding.

Strandings Associated With MFAS

    Over the past 16 years, there have been five stranding events 
coincident with military mid-frequency sonar use in which exposure to 
sonar is believed to have been a contributing factor: Greece (1996); 
the Bahamas (2000); Madeira (2000); Canary Islands (2002); and Spain 
(2006). Additionally, in 2004, during the Rim of the Pacific (RIMPAC) 
exercises, between 150 and 200 usually pelagic melon-headed whales 
occupied the shallow waters of Hanalei Bay, Kauai, Hawaii for over 28 
hours. NMFS determined that MFAS was a plausible, if not likely, 
contributing factor in what may have been a confluence of events that 
led to the stranding. A number of other stranding events coincident 
with the operation of mid-frequency 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 and only one of these stranding events, the Bahamas (2000), 
was associated with exercises conducted by the U.S. Navy. Most 
recently, the Independent Scientific Review Panel investigating 
potential contributing factors to a 2008 mass stranding of melon-headed 
whales in Antsohihy, Madagascar released its final report suggesting 
that the stranding was likely initially triggered by an industry 
seismic survey. This report suggests that the operation of a commercial 
high-powered 12 kHz multi-beam echosounder during an industry seismic 
survey was a plausible and likely initial trigger that caused a large 
group of melon-headed whales to leave their typical habitat and then 
ultimately strand as a result of secondary factors such as 
malnourishment and dehydration. The report indicates that the risk of 
this particular convergence of factors and ultimate outcome is likely 
very low, but recommends that the potential be considered in 
environmental planning. Because of the association between tactical 
mid-frequency active sonar use and a small number of marine mammal 
strandings, the Navy and NMFS have been considering and addressing the 
potential for strandings in association with Navy activities for years. 
In addition to a suite of mitigation intended to more broadly minimize 
impacts to marine mammals, the Navy and NMFS have a detailed Stranding 
Response Plan that outlines reporting, communication, and response 
protocols intended both to minimize the impacts of, and enhance the 
analysis of, any potential stranding in areas where the Navy operates.
    Greece (1996)--Twelve Cuvier's beaked whales stranded atypically 
(in both time and space) along a 38.2-km strand of the Kyparissiakos 
Gulf coast on May 12 and 13, 1996 (Frantzis, 1998). From May 11 through 
May 15, the North Atlantic Treaty Organization (NATO) research vessel 
Alliance was conducting sonar tests with signals of 600 Hz and 3 kHz 
and source levels of 228 and 226 dB re: 1[mu]Pa, respectively (D'Amico 
and Verboom, 1998; D'Spain et al., 2006). The timing and location of 
the testing encompassed the time and location of the strandings 
(Frantzis, 1998).
    Necropsies of eight of the animals were performed but were limited 
to basic external examination and sampling of stomach contents, blood, 
and skin. No ears or organs were collected, and no histological samples 
were preserved. No apparent abnormalities or wounds were found. 
Examination of photos of the animals, taken soon after their death, 
revealed that the eyes of at least four of the individuals were 
bleeding. Photos were taken soon after their death (Frantzis, 2004). 
Stomach contents contained the flesh of cephalopods, indicating that 
feeding had recently taken place (Frantzis, 1998).
    All available information regarding the conditions associated with 
this stranding event were compiled, and many potential causes were 
examined including major pollution events, prominent tectonic activity, 
unusual physical or meteorological events,

[[Page 9972]]

magnetic anomalies, epizootics, and conventional military activities 
(International Council for the Exploration of the Sea, 2005a). However, 
none of these potential causes coincided in time or space with the mass 
stranding, or could explain its characteristics (International Council 
for the Exploration of the Sea, 2005a). The robust condition of the 
animals, plus the recent stomach contents, is inconsistent with 
pathogenic causes. In addition, environmental causes can be ruled out 
as there were no unusual environmental circumstances or events before 
or during this time period and within the general proximity (Frantzis, 
2004).
    Because of the rarity of this mass stranding of Cuvier's beaked 
whales in the Kyparissiakos Gulf (first one in history), the 
probability for the two events (the military exercises and the 
strandings) to coincide in time and location, while being independent 
of each other, was thought to be extremely low (Frantzis, 1998). 
However, because full necropsies had not been conducted, and no 
abnormalities were noted, the cause of the strandings could not be 
precisely determined (Cox et al., 2006). A Bioacoustics Panel convened 
by NATO concluded that the evidence available did not allow them to 
accept or reject sonar exposures as a causal agent in these stranding 
events. The analysis of this stranding event provided support for, but 
no clear evidence for, the cause-and-effect relationship of tactical 
sonar training activities and beaked whale strandings (Cox et al., 
2006).
    Bahamas (2000)--NMFS and the Navy prepared a joint report 
addressing the multi-species stranding in the Bahamas in 2000, which 
took place within 24 hours of U.S. Navy ships using MFAS as they passed 
through the Northeast and Northwest Providence Channels on March 15-16, 
2000. The ships, which operated both AN/SQS-53C and AN/SQS-56, moved 
through the channel while emitting sonar pings approximately every 24 
seconds. Of the 17 cetaceans that stranded over a 36-hr period 
(Cuvier's beaked whales, Blainville's beaked whales, minke whales, and 
a spotted dolphin), seven animals died on the beach (five Cuvier's 
beaked whales, one Blainville's beaked whale, and the spotted dolphin), 
while the other 10 were returned to the water alive (though their 
ultimate fate is unknown). As discussed in the Bahamas report (DOC/DON, 
2001), there is no likely association between the minke whale and 
spotted dolphin strandings and the operation of MFAS.
    Necropsies were performed on five of the stranded beaked whales. 
All five necropsied beaked whales were in good body condition, showing 
no signs of infection, disease, ship strike, blunt trauma, or fishery 
related injuries, and three still had food remains in their stomachs. 
Auditory structural damage was discovered in four of the whales, 
specifically bloody effusions or hemorrhaging around the ears. 
Bilateral intracochlear and unilateral temporal region subarachnoid 
hemorrhage, with blood clots in the lateral ventricles, were found in 
two of the whales. Three of the whales had small hemorrhages in their 
acoustic fats (located along the jaw and in the melon).
    A comprehensive investigation was conducted and all possible causes 
of the stranding event were considered, whether they seemed likely at 
the outset or not. Based on the way in which the strandings coincided 
with ongoing naval activity involving tactical MFAS use, in terms of 
both time and geography, the nature of the physiological effects 
experienced by the dead animals, and the absence of any other acoustic 
sources, the investigation team concluded that MFAS aboard U.S. Navy 
ships that were in use during the active sonar exercise in question 
were the most plausible source of this acoustic or impulse trauma to 
beaked whales. This sound source was active in a complex environment 
that included the presence of a surface duct, unusual and steep 
bathymetry, a constricted channel with limited egress, intensive use of 
multiple, active sonar units over an extended period of time, and the 
presence of beaked whales that appear to be sensitive to the 
frequencies produced by these active sonars. The investigation team 
concluded that the cause of this stranding event was the confluence of 
the Navy MFAS and these contributory factors working together, and 
further recommended that the Navy avoid operating MFAS in situations 
where these five factors would be likely to occur. This report does not 
conclude that all five of these factors must be present for a stranding 
to occur, nor that beaked whales are the only species that could 
potentially be affected by the confluence of the other factors. Based 
on this, NMFS believes that the operation of MFAS in situations where 
surface ducts exist, or in marine environments defined by steep 
bathymetry and/or constricted channels may increase the likelihood of 
producing a sound field with the potential to cause cetaceans 
(especially beaked whales) to strand, and therefore, suggests the need 
for increased vigilance while operating MFAS in these areas, especially 
when beaked whales (or potentially other deep divers) are likely 
present.
    Madeira, Spain (2000)--From May 10-14, 2000, three Cuvier's beaked 
whales were found atypically stranded on two islands in the Madeira 
archipelago, Portugal (Cox et al., 2006). A fourth animal was reported 
floating in the Madeiran waters by fisherman but did not come ashore 
(Woods Hole Oceanographic Institution, 2005). Joint NATO amphibious 
training peacekeeping exercises involving participants from 17 
countries 80 warships, took place in Portugal during May 2-15, 2000.
    The bodies of the three stranded whales were examined post mortem 
(Woods Hole Oceanographic Institution, 2005), though only one of the 
stranded whales was fresh enough (24 hours after stranding) to be 
necropsied (Cox et al., 2006). Results from the necropsy revealed 
evidence of hemorrhage and congestion in the right lung and both 
kidneys (Cox et al., 2006). There was also evidence of intercochlear 
and intracranial hemorrhage similar to that which was observed in the 
whales that stranded in the Bahamas event (Cox et al., 2006). There 
were no signs of blunt trauma, and no major fractures (Woods Hole 
Oceanographic Institution, 2005). The cranial sinuses and airways were 
found to be clear with little or no fluid deposition, which may 
indicate good preservation of tissues (Woods Hole Oceanographic 
Institution, 2005).
    Several observations on the Madeira stranded beaked whales, such as 
the pattern of injury to the auditory system, are the same as those 
observed in the Bahamas strandings. Blood in and around the eyes, 
kidney lesions, pleural hemorrhages, and congestion in the lungs are 
particularly consistent with the pathologies from the whales stranded 
in the Bahamas, and are consistent with stress and pressure related 
trauma. The similarities in pathology and stranding patterns between 
these two events suggest that a similar pressure event may have 
precipitated or contributed to the strandings at both sites (Woods Hole 
Oceanographic Institution, 2005).
    Even though no definitive causal link can be made between the 
stranding event and naval exercises, certain conditions may have 
existed in the exercise area that, in their aggregate, may have 
contributed to the marine mammal strandings (Freitas, 2004): Exercises 
were conducted in areas of at least 547 fathoms (1,000 m) depth near a 
shoreline where there is a rapid change in bathymetry on the order of 
547 to 3,281 fathoms (1,000 to 6,000 m) occurring across a relatively 
short

[[Page 9973]]

horizontal distance (Freitas, 2004); multiple ships were operating 
around Madeira, though it is not known if MFAS was used, and the 
specifics of the sound sources used are unknown (Cox et al., 2006, 
Freitas, 2004); and exercises took place in an area surrounded by 
landmasses separated by less than 35 nm (65 km) and at least 10 nm (19 
km) in length, or in an embayment. Exercises involving multiple ships 
employing MFAS near land may produce sound directed towards a channel 
or embayment that may cut off the lines of egress for marine mammals 
(Freitas, 2004).
    Canary Islands, Spain (2002)--The southeastern area within the 
Canary Islands is well known for aggregations of beaked whales due to 
its ocean depths of greater than 547 fathoms (1,000 m) within a few 
hundred meters of the coastline (Fernandez et al., 2005). On September 
24, 2002, 14 beaked whales were found stranded on Fuerteventura and 
Lanzarote Islands in the Canary Islands (International Council for 
Exploration of the Sea, 2005a). Seven whales died, while the remaining 
seven live whales were returned to deeper waters (Fernandez et al., 
2005). Four beaked whales were found stranded dead over the next three 
days either on the coast or floating offshore. These strandings 
occurred within near proximity of an international naval exercise that 
utilized MFAS and involved numerous surface warships and several 
submarines. Strandings began about 4 hours after the onset of MFAS 
activity (International Council for Exploration of the Sea, 2005a; 
Fernandez et al., 2005).
    Eight Cuvier's beaked whales, one Blainville's beaked whale, and 
one Gervais' beaked whale were necropsied, six of them within 12 hours 
of stranding (Fernandez et al., 2005). No pathogenic bacteria were 
isolated from the carcasses (Jepson et al., 2003). The animals 
displayed severe vascular congestion and hemorrhage especially around 
the tissues in the jaw, ears, brain, and kidneys, displaying marked 
disseminated microvascular hemorrhages associated with widespread fat 
emboli (Jepson et al., 2003; International Council for Exploration of 
the Sea, 2005a). Several organs contained intravascular bubbles, 
although definitive evidence of gas embolism in vivo is difficult to 
determine after death (Jepson et al., 2003). The livers of the 
necropsied animals were the most consistently affected organ, which 
contained macroscopic gas-filled cavities and had variable degrees of 
fibrotic encapsulation. In some animals, cavitary lesions had 
extensively replaced the normal tissue (Jepson et al., 2003). Stomachs 
contained a large amount of fresh and undigested contents, suggesting a 
rapid onset of disease and death (Fernandez et al., 2005). Head and 
neck lymph nodes were enlarged and congested, and parasites were found 
in the kidneys of all animals (Fernandez et al., 2005).
    The association of NATO MFAS use close in space and time to the 
beaked whale strandings, and the similarity between this stranding 
event and previous beaked whale mass strandings coincident with sonar 
use, suggests that a similar scenario and causative mechanism of 
stranding may be shared between the events. Beaked whales stranded in 
this event demonstrated brain and auditory system injuries, 
hemorrhages, and congestion in multiple organs, similar to the 
pathological findings of the Bahamas and Madeira stranding events. In 
addition, the necropsy results of Canary Islands stranding event lead 
to the hypothesis that the presence of disseminated and widespread gas 
bubbles and fat emboli were indicative of nitrogen bubble formation, 
similar to what might be expected in decompression sickness (Jepson et 
al., 2003; Fern[aacute]ndez et al., 2005).
    Hanalei Bay (2004)--On July 3 and 4, 2004, approximately 150 to 200 
melon-headed whales occupied the shallow waters of the Hanalei Bay, 
Kaua'i, Hawaii for over 28 hrs. Attendees of a canoe blessing observed 
the animals entering the Bay in a single wave formation at 7 a.m. on 
July 3, 2004. The animals were observed moving back into the shore from 
the mouth of the Bay at 9 a.m. The usually pelagic animals milled in 
the shallow bay and were returned to deeper water with human assistance 
beginning at 9:30 a.m. on July 4, 2004, and were out of sight by 10:30 
a.m.
    Only one animal, a calf, was known to have died following this 
event. The animal was noted alive and alone in the Bay on the afternoon 
of July 4, 2004, and was found dead in the Bay the morning of July 5, 
2004. A full necropsy, magnetic resonance imaging, and computerized 
tomography examination were performed on the calf to determine the 
manner and cause of death. The combination of imaging, necropsy and 
histological analyses found no evidence of infectious, internal 
traumatic, congenital, or toxic factors. Cause of death could not be 
definitively determined, but it is likely that maternal separation, 
poor nutritional condition, and dehydration contributed to the final 
demise of the animal. Although it is not known when the calf was 
separated from its mother, the animals' movement into the Bay and 
subsequent milling and re-grouping may have contributed to the 
separation or lack of nursing, especially if the maternal bond was weak 
or this was an inexperienced mother with her first calf.
    Environmental factors, abiotic and biotic, were analyzed for any 
anomalous occurrences that would have contributed to the animals 
entering and remaining in Hanalei Bay. The Bay's bathymetry is similar 
to many other sites within the Hawaiian Island chain and dissimilar to 
sites that have been associated with mass strandings in other parts of 
the U.S. The weather conditions appeared to be normal for that time of 
year with no fronts or other significant features noted. There was no 
evidence of unusual distribution, occurrence of predator or prey 
species, or unusual harmful algal blooms, although Mobley et al. (2007) 
suggested that the full moon cycle that occurred at that time may have 
influenced a run of squid into the Bay. Weather patterns and bathymetry 
that have been associated with mass strandings elsewhere were not found 
to occur in this instance.
    The Hanalei event was spatially and temporally correlated with 
RIMPAC. Official sonar training and tracking exercises in the Pacific 
Missile Range Facility (PMRF) warning area did not commence until 
approximately 8 a.m. on July 3 and were thus ruled out as a possible 
trigger for the initial movement into the Bay. However, six naval 
surface vessels transiting to the operational area on July 2 
intermittently transmitted active sonar (for approximately 9 hours 
total from 1:15 p.m. to 12:30 a.m.) as they approached from the south. 
The potential for these transmissions to have triggered the whales' 
movement into Hanalei Bay was investigated. Analyses with the 
information available indicated that animals to the south and east of 
Kaua'i could have detected active sonar transmissions on July 2, and 
reached Hanalei Bay on or before 7 a.m. on July 3. However, data 
limitations regarding the position of the whales prior to their arrival 
in the Bay, the magnitude of sonar exposure, behavioral responses of 
melon-headed whales to acoustic stimuli, and other possible relevant 
factors preclude a conclusive finding regarding the role of sonar in 
triggering this event. Propagation modeling suggests that transmissions 
from sonar use during the July 3 exercise in the PMRF warning area may 
have been detectable at the mouth of the Bay. If the animals responded 
negatively to these signals, it may have contributed to their continued 
presence in the Bay. The U.S.

[[Page 9974]]

Navy ceased all active sonar transmissions during exercises in this 
range on the afternoon of July 3. Subsequent to the cessation of sonar 
use, the animals were herded out of the Bay.
    While causation of this stranding event may never be unequivocally 
determined, NMFS consider the active sonar transmissions of July 2-3, 
2004, a plausible, if not likely, contributing factor in what may have 
been a confluence of events. This conclusion is based on the following: 
(1) The evidently anomalous nature of the stranding; (2) its close 
spatiotemporal correlation with wide-scale, sustained use of sonar 
systems previously associated with stranding of deep-diving marine 
mammals; (3) the directed movement of two groups of transmitting 
vessels toward the southeast and southwest coast of Kauai; (4) the 
results of acoustic propagation modeling and an analysis of possible 
animal transit times to the Bay; and (5) the absence of any other 
compelling causative explanation. The initiation and persistence of 
this event may have resulted from an interaction of biological and 
physical factors. The biological factors may have included the presence 
of an apparently uncommon, deep-diving cetacean species (and possibly 
an offshore, non-resident group), social interactions among the animals 
before or after they entered the Bay, and/or unknown predator or prey 
conditions. The physical factors may have included the presence of 
nearby deep water, multiple vessels transiting in a directed manner 
while transmitting active sonar over a sustained period, the presence 
of surface sound ducting conditions, and/or intermittent and random 
human interactions while the animals were in the Bay.
    A separate event involving melon-headed whales and rough-toothed 
dolphins took place over the same period of time in the Northern 
Mariana Islands (Jefferson et al., 2006), which is several thousand 
miles from Hawaii. Some 500 to 700 melon-headed whales came into 
Sasanhaya Bay on July 4, 2004, near the island of Rota and then left of 
their own accord after 5.5 hours; no known active sonar transmissions 
occurred in the vicinity of that event. The Rota incident led to 
scientific debate regarding what, if any, relationship the event had to 
the simultaneous events in Hawaii and whether they might be related by 
some common factor (e.g., there was a full moon on July 2, 2004, as 
well as during other melon-headed whale strandings and nearshore 
aggregations (Brownell et al., 2009; Lignon et al., 2007; Mobley et 
al., 2007). Brownell et al. (2009) compared the two incidents, along 
with one other stranding incident at Nuka Hiva in French Polynesia and 
normal resting behaviors observed at Palmyra Island, in regard to 
physical features in the areas, melon-headed whale behavior, and lunar 
cycles. Brownell et al., (2009) concluded that the rapid entry of the 
whales into Hanalei Bay, their movement into very shallow water far 
from the 100-m contour, their milling behavior (typical pre-stranding 
behavior), and their reluctance to leave the bay constituted an unusual 
event that was not similar to the events that occurred at Rota (but was 
similar to the events at Palmyra), which appear to be similar to 
observations of melon-headed whales resting normally at Palmyra Island. 
Additionally, there was no correlation between lunar cycle and the 
types of behaviors observed in the Brownell et al. (2009) examples.
    Spain (2006)--The Spanish Cetacean Society reported an atypical 
mass stranding of four beaked whales that occurred January 26, 2006, on 
the southeast coast of Spain, near Mojacar (Gulf of Vera) in the 
Western Mediterranean Sea. According to the report, two of the whales 
were discovered the evening of January 26 and were found to be still 
alive. Two other whales were discovered during the day on January 27, 
but had already died. The first three animals were located near the 
town of Mojacar and the fourth animal was found dead, a few kilometers 
north of the first three animals. From January 25-26, 2006, Standing 
NATO Response Force Maritime Group Two (five of seven ships including 
one U.S. ship under NATO Operational Control) had conducted active 
sonar training against a Spanish submarine within 50 nm (93 km) of the 
stranding site.
    Veterinary pathologists necropsied the two male and two female 
Cuvier's beaked whales. According to the pathologists, the most likely 
primary cause of this type of beaked whale mass stranding event was 
anthropogenic acoustic activities, most probably anti-submarine MFAS 
used during the military naval exercises. However, no positive acoustic 
link was established as a direct cause of the stranding. Even though no 
causal link can be made between the stranding event and naval 
exercises, certain conditions may have existed in the exercise area 
that, in their aggregate, may have contributed to the marine mammal 
strandings (Freitas, 2004): Exercises were conducted in areas of at 
least 547 fathoms (1,000 m) depth near a shoreline where there is a 
rapid change in bathymetry on the order of 547 to 3,281 fathoms (1,000 
to 6,000 m) occurring across a relatively short horizontal distance 
(Freitas, 2004); multiple ships (in this instance, five) were operating 
MFAS in the same area over extended periods of time (in this case, 20 
hours) in close proximity; and exercises took place in an area 
surrounded by landmasses, or in an embayment. Exercises involving 
multiple ships employing MFAS near land may have produced sound 
directed towards a channel or embayment that may have cut off the lines 
of egress for the affected marine mammals (Freitas, 2004).

Association Between Mass Stranding Events and Exposure to MFAS

    Several authors have noted similarities between some of these 
stranding incidents: They occurred in islands or archipelagoes with 
deep water nearby, several appeared to have been associated with 
acoustic waveguides like surface ducting, and the sound fields created 
by ships transmitting MFAS (Cox et al., 2006; D'Spain et al., 2006). 
Although Cuvier's beaked whales have been the most common species 
involved in these stranding events (81 percent of the total number of 
stranded animals), other beaked whales (including Mesoplodon europeaus, 
M. densirostris, and Hyperoodon ampullatus) comprise 14 percent of the 
total. Other species (Stenella coeruleoalba, Kogia breviceps and 
Balaenoptera acutorostrata) have stranded, but in much lower numbers 
and less consistently than beaked whales.
    Based on the evidence available, however, NMFS cannot determine 
whether (a) Cuvier's beaked whale is more prone to injury from high-
intensity sound than other species; (b) their behavioral responses to 
sound makes them more likely to strand; or (c) they are more likely to 
be exposed to MFAS than other cetaceans (for reasons that remain 
unknown). Because the association between active sonar exposures and 
marine mammals mass stranding events is not consistent--some marine 
mammals strand without being exposed to sonar and some sonar 
transmissions are not associated with marine mammal stranding events 
despite their co-occurrence--other risk factors or a grouping of risk 
factors probably contribute to these stranding events.

Behaviorally Mediated Responses to MFAS That May Lead To Stranding

    Although the confluence of Navy MFAS with the other contributory 
factors noted in the report was

[[Page 9975]]

identified as the cause of the 2000 Bahamas stranding event, the 
specific mechanisms that led to that stranding (or the others) are not 
understood, and there is uncertainty regarding the ordering of effects 
that led to the stranding. It is unclear whether beaked whales were 
directly injured by sound (e.g., acoustically mediated bubble growth, 
as addressed above) prior to stranding or whether a behavioral response 
to sound occurred that ultimately caused the beaked whales to be 
injured and strand.
    Although causal relationships between beaked whale stranding events 
and active sonar remain unknown, several authors have hypothesized that 
stranding events involving these species in the Bahamas and Canary 
Islands may have been triggered when the whales changed their dive 
behavior in a startled response to exposure to active sonar or to 
further avoid exposure (Cox et al., 2006; Rommel et al., 2006). These 
authors proposed three mechanisms by which the behavioral responses of 
beaked whales upon being exposed to active sonar might result in a 
stranding event. These include the following: Gas bubble formation 
caused by excessively fast surfacing; remaining at the surface too long 
when tissues are supersaturated with nitrogen; or diving prematurely 
when extended time at the surface is necessary to eliminate excess 
nitrogen. More specifically, beaked whales that occur in deep waters 
that are in close proximity to shallow waters (for example, the 
``canyon areas'' that are cited in the Bahamas stranding event; see 
D'Spain and D'Amico, 2006), may respond to active sonar by swimming 
into shallow waters to avoid further exposures and strand if they were 
not able to swim back to deeper waters. Second, beaked whales exposed 
to active sonar might alter their dive behavior. Changes in their dive 
behavior might cause them to remain at the surface or at depth for 
extended periods of time which could lead to hypoxia directly by 
increasing their oxygen demands or indirectly by increasing their 
energy expenditures (to remain at depth) and increase their oxygen 
demands as a result. If beaked whales are at depth when they detect a 
ping from an active sonar transmission and change their dive profile, 
this could lead to the formation of significant gas bubbles, which 
could damage multiple organs or interfere with normal physiological 
function (Cox et al., 2006; Rommel et al., 2006; Zimmer and Tyack, 
2007). Baird et al. (2005) found that slow ascent rates from deep dives 
and long periods of time spent within 50 m of the surface were typical 
for both Cuvier's and Blainville's beaked whales, the two species 
involved in mass strandings related to naval sonar. These two 
behavioral mechanisms may be necessary to purge excessive dissolved 
nitrogen concentrated in their tissues during their frequent long dives 
(Baird et al., 2005). Baird et al. (2005) further suggests that 
abnormally rapid ascents or premature dives in response to high-
intensity sonar could indirectly result in physical harm to the beaked 
whales, through the mechanisms described above (gas bubble formation or 
non-elimination of excess nitrogen).
    Because many species of marine mammals make repetitive and 
prolonged dives to great depths, it has long been assumed that marine 
mammals have evolved physiological mechanisms to protect against the 
effects of rapid and repeated decompressions. Although several 
investigators have identified physiological adaptations that may 
protect marine mammals against nitrogen gas supersaturation (alveolar 
collapse and elective circulation; Kooyman et al., 1972; Ridgway and 
Howard, 1979), Ridgway and Howard (1979) reported that bottlenose 
dolphins that were trained to dive repeatedly had muscle tissues that 
were substantially supersaturated with nitrogen gas. Houser et al. 
(2001) used these data to model the accumulation of nitrogen gas within 
the muscle tissue of other marine mammal species and concluded that 
cetaceans that dive deep and have slow ascent or descent speeds would 
have tissues that are more supersaturated with nitrogen gas than other 
marine mammals. Based on these data, Cox et al. (2006) hypothesized 
that a critical dive sequence might make beaked whales more prone to 
stranding in response to acoustic exposures. The sequence began with 
(1) very deep (to depths as deep as 2 kilometers) and long (as long as 
90 minutes) foraging dives; (2) relatively slow, controlled ascents; 
and (3) a series of ``bounce'' dives between 100 and 400 m in depth 
(also see Zimmer and Tyack, 2007). They concluded that acoustic 
exposures that disrupted any part of this dive sequence (for example, 
causing beaked whales to spend more time at surface without the bounce 
dives that are necessary to recover from the deep dive) could produce 
excessive levels of nitrogen supersaturation in their tissues, leading 
to gas bubble and emboli formation that produces pathologies similar to 
decompression sickness.
    Zimmer and Tyack (2007) modeled nitrogen tension and bubble growth 
in several tissue compartments for several hypothetical dive profiles 
and concluded that repetitive shallow dives (defined as a dive where 
depth does not exceed the depth of alveolar collapse, approximately 72 
m for Ziphius), perhaps as a consequence of an extended avoidance 
reaction to sonar sound, could pose a risk for decompression sickness 
and that this risk should increase with the duration of the response. 
Their models also suggested that unrealistically rapid ascent rates of 
ascent from normal dive behaviors are unlikely to result in 
supersaturation to the extent that bubble formation would be expected. 
Tyack et al. (2006) suggested that emboli observed in animals exposed 
to mid-frequency range sonar (Jepson et al., 2003; Fernandez et al., 
2005; Fern[aacute]ndez et al., 2012) could stem from a behavioral 
response that involves repeated dives shallower than the depth of lung 
collapse. Given that nitrogen gas accumulation is a passive process 
(i.e. nitrogen is metabolically inert), a bottlenose dolphin was 
trained to repetitively dive a profile predicted to elevate nitrogen 
saturation to the point that nitrogen bubble formation was predicted to 
occur. However, inspection of the vascular system of the dolphin via 
ultrasound did not demonstrate the formation of asymptomatic nitrogen 
gas bubbles (Houser et al., 2007). Baird et al. (2008), in a beaked 
whale tagging study off Hawaii, showed that deep dives are equally 
common during day or night, but ``bounce dives'' are typically a 
daytime behavior, possibly associated with visual predator avoidance. 
This may indicate that ``bounce dives'' are associated with something 
other than behavioral regulation of dissolved nitrogen levels, which 
would be necessary day and night.
    If marine mammals respond to a Navy vessel that is transmitting 
active sonar in the same way that they might respond to a predator, 
their probability of flight responses 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). The probability of flight 
responses should also increase as received levels of active sonar 
increase (and the ship is, therefore, closer) and as ship speeds 
increase (that is, as approach speeds increase). For example, the 
probability of flight responses in Dall's sheep (Ovis dalli dalli) 
(Frid 2001a, b), ringed seals (Phoca hispida) (Born et al., 1999), 
Pacific brant (Branta bernic nigricans) and Canada geese (B. 
Canadensis) increased as a helicopter or

[[Page 9976]]

fixed-wing aircraft approached groups of these animals more directly 
(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).
    Despite the many theories involving bubble formation (both as a 
direct cause of injury (see Acoustically Mediated Bubble Growth 
Section) and an indirect cause of stranding (See Behaviorally Mediated 
Bubble Growth Section), Southall et al., (2007) summarizes that there 
is either scientific disagreement or a lack of information regarding 
each of the following important points: (1) Received acoustical 
exposure conditions for animals involved in stranding events; (2) 
pathological interpretation of observed lesions in stranded marine 
mammals; (3) acoustic exposure conditions required to induce such 
physical trauma directly; (4) whether noise exposure may cause 
behavioral reactions (such as atypical diving behavior) that 
secondarily cause bubble formation and tissue damage; and (5) the 
extent the post mortem artifacts introduced by decomposition before 
sampling, handling, freezing, or necropsy procedures affect 
interpretation of observed lesions.

Strandings in the GOA TMAA

    Northern Edge--Prior to the start of Northern Edge 2015 (a joint 
training exercise in the GOA TMAA hosted by Alaskan Command) and before 
Navy vessels were in the Gulf of Alaska, the Navy was informed by NMFS 
of various marine mammals found dead in the Gulf of Alaska and that 
NMFS was attempting to obtain samples from them. It has been reported 
that at least nine drifting and floating fin whales and multiple 
pinniped species were found in Gulf of Alaska waters as early as May 
23, 2015 between Kodiak Island to Unimak Pass. NMFS is still 
investigating these findings but a possible cause referenced has been 
an algal bloom. During Northern Edge 2015, two Navy vessels training in 
the Gulf of Alaska on separate days encountered a well-decayed whale 
carcass. This whale or whales may possibly be the same animal observed 
by both ships, and given the stage of decomposition, might have been 
one of the floating whales reported by other entities to NMFS before 
Northern Edge began. The ships followed Navy reporting procedures and 
the information was provided to NMFS to aid in the investigation. There 
is no causal connection with Navy activities given the advanced stage 
of decomposition and gap of timing of when Navy maritime training 
events began.

Impulsive Sources

    Underwater explosive detonations send a shock wave and sound energy 
through the water and can release gaseous by-products, create an 
oscillating bubble, or cause a plume of water to shoot up from the 
water surface. The shock wave and accompanying noise are of most 
concern to marine animals. Depending on the intensity of the shock wave 
and size, location, and depth of the animal, an animal can be injured, 
killed, suffer non-lethal physical effects, experience hearing related 
effects with or without behavioral responses, or exhibit temporary 
behavioral responses or tolerance from hearing the blast sound. 
Generally, exposures to higher levels of impulse and pressure levels 
would result in greater impacts to an individual animal.
    Injuries resulting from a shock wave take place at boundaries 
between tissues of different densities. Different velocities are 
imparted to tissues of different densities, and this can lead to their 
physical disruption. Blast effects are greatest at the gas-liquid 
interface (Landsberg, 2000). Gas-containing organs, particularly the 
lungs and gastrointestinal tract, are especially susceptible (Goertner, 
1982; Hill, 1978; Yelverton et al., 1973). In addition, gas-containing 
organs including the nasal sacs, larynx, pharynx, trachea, and lungs 
may be damaged by compression/expansion caused by the oscillations of 
the blast gas bubble (Reidenberg and Laitman, 2003). Intestinal walls 
can bruise or rupture, with subsequent hemorrhage and escape of gut 
contents into the body cavity. Less severe gastrointestinal tract 
injuries include contusions, petechiae (small red or purple spots 
caused by bleeding in the skin), and slight hemorrhaging (Yelverton et 
al., 1973).
    Because the ears are the most sensitive to pressure, they are the 
organs most sensitive to injury (Ketten, 2000). Sound-related damage 
associated with sound energy from detonations can be theoretically 
distinct from injury from the shock wave, particularly farther from the 
explosion. If a noise is audible to an animal, it has the potential to 
damage the animal's hearing by causing decreased sensitivity (Ketten, 
1995). Sound-related trauma can be lethal or sublethal. Lethal impacts 
are those that result in immediate death or serious debilitation in or 
near an intense source and are not, technically, pure acoustic trauma 
(Ketten, 1995). Sublethal impacts include hearing loss, which is caused 
by exposures to perceptible sounds. Severe damage (from the shock wave) 
to the ears includes tympanic membrane rupture, fracture of the 
ossicles, damage to the cochlea, hemorrhage, and cerebrospinal fluid 
leakage into the middle ear. Moderate injury implies partial hearing 
loss due to tympanic membrane rupture and blood in the middle ear. 
Permanent hearing loss also can occur when the hair cells are damaged 
by one very loud event, as well as by prolonged exposure to a loud 
noise or chronic exposure to noise. The level of impact from blasts 
depends on both an animal's location and, at outer zones, on its 
sensitivity to the residual noise (Ketten, 1995).
    There have been fewer studies addressing the behavioral effects of 
explosives on marine mammals compared to MFAS/HFAS. However, though the 
nature of the sound waves emitted from an explosion are different (in 
shape and rise time) from MFAS/HFAS, NMFS still anticipates the same 
sorts of behavioral responses to result from repeated explosive 
detonations (a smaller range of likely less severe responses (i.e., not 
rising to the level of MMPA harassment) would be expected to occur as a 
result of exposure to a single explosive detonation that was not 
powerful enough or close enough to the animal to cause TTS or injury).
    Baleen whales have shown a variety of responses to impulse sound 
sources, including avoidance, reduced surface intervals, altered 
swimming behavior, and changes in vocalization rates (Richardson et 
al., 1995; Gordon et al., 2003; Southall, 2007). While most bowhead 
whales did not show active avoidance until within 8 km of seismic 
vessels (Richardson et al., 1995), some whales avoided vessels by more 
than 20 km at received levels as low as 120 dB re 1 [mu]Pa rms. 
Additionally, Malme et al. (1988) observed clear changes in diving and 
respiration patterns in bowheads at ranges up to 73 km from seismic 
vessels, with received levels as low as 125 dB re 1 [mu]Pa.
    Gray whales migrating along the U.S. west coast showed avoidance 
responses to seismic vessels by 10 percent of animals at 164 dB re 1 
[mu]Pa, and by 90 percent of animals at 190 dB re 1 [mu]Pa, with 
similar results for whales in the Bering Sea (Malme 1986, 1988). In 
contrast, noise from seismic surveys was not found to impact feeding 
behavior or exhalation rates while resting or diving in western gray 
whales off the coast of Russia (Yazvenko et al., 2007; Gailey et al., 
2007).

[[Page 9977]]

    Humpback whales showed avoidance behavior at ranges of 5-8 km from 
a seismic array during observational studies and controlled exposure 
experiments in western Australia (McCauley, 1998; Todd et al., 1996) 
found no clear short-term behavioral responses by foraging humpbacks to 
explosions associated with construction operations in Newfoundland, but 
did see a trend of increased rates of net entanglement and a shift to a 
higher incidence of net entanglement closer to the noise source.
    Seismic pulses at average received levels of 131 dB re 1 
micropascal squared second ([mu]Pa\2\-s) caused blue whales to increase 
call production (Di Iorio and Clark, 2010). In contrast, McDonald et 
al. (1995) tracked a blue whale with seafloor seismometers and reported 
that it stopped vocalizing and changed its travel direction at a range 
of 10 km from the seismic vessel (estimated received level 143 dB re 1 
[mu]Pa peak-to-peak). These studies demonstrate that even low levels of 
noise received far from the noise source can induce behavioral 
responses.
    Madsen et al. (2006) and Miller et al. (2009) tagged and monitored 
eight sperm whales in the Gulf of Mexico exposed to seismic airgun 
surveys. Sound sources were from approximately 2 to 7 nm away from the 
whales and based on multipath propagation received levels were as high 
as 162 dB SPL re 1 [mu]Pa with energy content greatest between 0.3 and 
3.0 kHz (Madsen, 2006). The whales showed no horizontal avoidance, 
although the whale that was approached most closely had an extended 
resting period and did not resume foraging until the airguns had ceased 
firing (Miller et al., 2009). The remaining whales continued to execute 
foraging dives throughout exposure; however, swimming movements during 
foraging dives were 6 percent lower during exposure than control 
periods, suggesting subtle effects of noise on foraging behavior 
(Miller et al., 2009). Captive bottlenose dolphins sometimes vocalized 
after an exposure to impulse sound from a seismic watergun (Finneran et 
al., 2010a).
    A review of behavioral reactions by pinnipeds to impulse noise can 
be found in Richardson et al. (1995) and Southall et al. (2007). 
Blackwell et al. (2004) observed that ringed seals exhibited little or 
no reaction to pipe-driving noise with mean underwater levels of 157 dB 
re 1 [mu]Pa rms and in air levels of 112 dB re 20 [mu]Pa, suggesting 
that the seals had habituated to the noise. In contrast, captive 
California sea lions avoided sounds from an impulse source at levels of 
165-170 dB re 1 [mu]Pa (Finneran et al., 2003b). Experimentally, 
G[ouml]tz and Janik (2011) tested underwater, startle responses to a 
startling sound (sound with a rapid rise time and a 93 dB sensation 
level [the level above the animal's threshold at that frequency]) and a 
non-startling sound (sound with the same level, but with a slower rise 
time) in wild-captured gray seals. The animals exposed to the startling 
treatment avoided a known food source, whereas animals exposed to the 
non-startling treatment did not react or habituated during the exposure 
period. The results of this study highlight the importance of the 
characteristics of the acoustic signal in an animal's response of 
habituation.

Vessels

    Ship strikes of cetaceans can cause major wounds, which may 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 in order to 
restore oxygen levels within their tissues after deep dives (e.g., the 
sperm whale). In addition, some 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). These species are primarily large, slow moving whales. Smaller 
marine mammals (e.g., bottlenose dolphin) move quickly through the 
water column and are often seen riding the bow wave of large ships. 
Marine mammal responses to vessels may include avoidance and changes in 
dive pattern (NRC, 2003).
    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. The 
authors concluded that most deaths occurred when a vessel was traveling 
in excess of 13 knots.
    Jensen and Silber (2003) detailed 292 records of known or probable 
ship strikes of all large whale species from 1975 to 2002. Of these, 
vessel speed at the time of collision was reported for 58 cases. Of 
these 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 knots. 
The majority (79 percent) of these strikes occurred at speeds of 13 
knots or greater. The average speed that resulted in serious injury or 
death was 18.6 knots. Pace and Silber (2005) found that the probability 
of death or serious injury increased rapidly with increasing vessel 
speed. Specifically, the predicted probability of serious injury or 
death increased from 45 to 75 percent as vessel speed increased from 10 
to 14 knots, and exceeded 90 percent at 17 knots. Higher speeds during 
collisions result in greater force of impact and also appear to 
increase the chance of severe injuries or death. While modeling studies 
have suggested that hydrodynamic forces pulling whales toward the 
vessel hull increase with increasing speed (Clyne, 1999; Knowlton et 
al., 1995), this is inconsistent with Silber et al. (2010), which 
demonstrated that there is no such relationship (i.e., hydrodynamic 
forces are independent of speed).
    The Jensen and Silber (2003) 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 
percentages of Navy traffic relative to overall large shipping traffic 
are very small (on the order of 2 percent).
    There are no records of any Navy vessel strikes to marine mammals 
during training or testing activities in the Study Area. There have 
been Navy vessel strikes of large whales in areas outside the Study 
Area, such as Hawaii and Southern California. However, these areas 
differ significantly from the Study Area given that both Hawaii and 
Southern California have a much higher number of Navy vessel activities 
and much higher densities of large whales.
    Other efforts have been undertaken to investigate the impact from 
vessels (both whale-watching and general vessel traffic noise) and 
demonstrated impacts do occur (Bain, 2002; Erbe, 2002; Lusseau, 2009; 
Williams et al., 2006, 2009, 2011b, 2013, 2014a, 2014b; Noren

[[Page 9978]]

et al., 2009; 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 generally intermittent Navy training and testing 
activities. For example, in an analysis of energy costs to killer 
whales, Williams et al. (2009) suggested that whale-watching in the 
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) recently reported 
on research in the Salish Sea involving the measurement of southern 
resident killer whale fecal hormones to assess two potential threats to 
the species recovery: Lack of prey (salmon) and impacts to behavior 
from vessel traffic. Ayres et al. (2012) suggested that the lack of 
prey overshadowed any population-level physiological impacts on 
southern resident killer whales from vessel traffic.
    Based on the implementation of Navy mitigation measures and the low 
density of Navy ships in the GOA TMAA, NMFS has concluded, 
preliminarily, that the probability of a ship strike is very low, 
especially for dolphins and porpoises, killer whales, social pelagic 
odontocetes and pinnipeds that are highly visible, and/or comparatively 
small and maneuverable. Though more probable because of their size, 
NMFS also believes that the likelihood of a Navy vessel striking a 
mysticete or sperm whale is also low with the implementation of 
mitigation measures and the low density of navy ships in the Study 
Area. The Navy did not request take from a ship strike, and based on 
our preliminary determination, NMFS is not recommending that they 
modify their request at this time. However, both NMFS and the Navy are 
currently engaged in a Section 7 consultation under the ESA, and that 
consultation will further inform our final decision.

Proposed Mitigation

    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.'' NMFS' duty under 
this ``least practicable adverse impact'' standard is to prescribe 
mitigation reasonably designed to minimize, to the extent practicable, 
any adverse population-level impacts, as well as habitat impacts. While 
population-level impacts are minimized by reducing impacts on 
individual marine mammals, not all takes have a reasonable potential 
for translating to population-level impacts. NMFS' objective under the 
``least practicable adverse impact'' standard is to design mitigation 
targeting those impacts on individual marine mammals that are 
reasonably likely to contribute to adverse population-level effects.
    The NDAA of 2004 amended the MMPA as it relates to military 
readiness activities and the 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.'' The training and testing activities 
described in the Navy's LOA application are considered military 
readiness activities.
    In Conservation Council for Hawaii v. National Marine Fisheries 
Service, No. 1:13-cv-00684 (D. Hawaii March 31, 2015), the court stated 
that NMFS ``appear[s] to think that [it] satisf[ies] the statutory 
`least practicable adverse impact' requirement with a `negligible 
impact' finding.'' In light of the court's decision, we take this 
opportunity to make clear our position that the ``negligible impact'' 
and ``least practicable adverse impact'' requirements are distinct, 
even though the focus of both is on population-level impacts.
    A population-level impact is an impact on the population numbers 
(survival) or growth and reproductive rates (recruitment) of a 
particular marine mammal species or stock. As we noted in the preamble 
to our general MMPA implementing regulations, not every population-
level impact violates the negligible impact requirement. As we 
explained, 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. Only insignificant impacts on long-term population levels and 
trends can be treated as negligible.'' See 54 FR 40338, 40341-42 
(September 29, 1989). Nevertheless, while insignificant impacts on 
population numbers or growth rates may satisfy the negligible impact 
requirement, such impacts still must be mitigated, to the extent 
practicable, under the ``least practicable adverse impact'' 
requirement. Thus, the negligible impact and least practicable adverse 
impact requirements are clearly distinct, even though both focus on 
population-level effects.
    Any mitigation measure(s) prescribed by NMFS should be able to 
accomplish, have a reasonable likelihood of accomplishing (based on 
current science), or contribute to accomplishing one or more of the 
general goals listed below:
    a. Avoid or minimize injury or death of marine mammals wherever 
possible (goals b, c, and d may contribute to this goal).
    b. Reduce the numbers of marine mammals (total number or number at 
biologically important time or location) exposed to received levels of 
MFAS/HFAS, underwater detonations, or other activities expected to 
result in the take of marine mammals (this goal may contribute to a, 
above, or to reducing harassment takes only).
    c. Reduce the number of times (total number or number at 
biologically important time or location) individuals would be exposed 
to received levels of MFAS/HFAS, underwater detonations, or other 
activities expected to result in the take of marine mammals (this goal 
may contribute to a, above, or to reducing harassment takes only).
    d. Reduce the intensity of exposures (either total number or number 
at biologically important time or location) to received levels of MFAS/
HFAS, underwater detonations, or other activities expected to result in 
the take of marine mammals (this goal may contribute to a, above, or to 
reducing the severity of harassment takes only).
    e. Avoid or minimize adverse effects to marine mammal habitat 
(including acoustic habitat), paying special attention to the food 
base, activities that block or limit passage to or from biologically 
important areas, permanent destruction of habitat, or temporary 
destruction/disturbance of habitat during a biologically important 
time.
    f. For monitoring directly related to mitigation--increase the 
probability of detecting marine mammals, thus allowing for more 
effective implementation of the mitigation (shut-down zone, etc.).
    Our final evaluation of measures that meet one or more of the above 
goals includes consideration of the following factors in relation to 
one another: The manner in which, and the degree to which, the 
successful implementation of the mitigation measures is expected to 
reduce population-level impacts to marine mammal species and stocks and 
impacts to their habitat; the proven or likely efficacy of the 
measures; and the practicability of the suite of measures

[[Page 9979]]

for applicant implementation, including consideration of personnel 
safety, practicality of implementation, and impact on the effectiveness 
of the military readiness activity.
    NMFS reviewed the proposed activities and the suite of proposed 
mitigation measures as described in the Navy's LOA application to 
determine if they would result in the least practicable adverse effect 
on marine mammals. NMFS worked with the Navy in the development of the 
Navy's initially proposed measures, which are informed by years of 
experience and monitoring. Below are the mitigation measures as agreed 
upon by the Navy and NMFS. For additional details regarding the Navy's 
mitigation measures, see Chapter 5 in the GOA DSEIS/OEIS.

Lookouts

    The Navy will have two types of Lookouts for the purposes of 
conducting visual observations: Those positioned on ships; and those 
positioned ashore, in aircraft, or on small boats. Lookouts positioned 
on ships will diligently observe the air and surface of the water. They 
will have multiple observation objectives, which include but are not 
limited to detecting the presence of biological resources and 
recreational or fishing boats, observing the mitigation zones, and 
monitoring for vessel and personnel safety concerns.
    Due to manning and space restrictions on aircraft, small boats, and 
some Navy ships, Lookouts for these platforms may be supplemented by 
the aircraft crew or pilot, boat crew, range site personnel, or shore-
side personnel. Lookouts positioned in minimally manned platforms may 
be responsible for tasks in addition to observing the air or surface of 
the water (e.g., navigation of a helicopter or small boat). However, 
all Lookouts will, considering personnel safety, practicality of 
implementation, and impact on the effectiveness of the activity, comply 
with the observation objectives described above for Lookouts positioned 
on ships.
    The procedural measures described in the remainder of this section 
primarily consist of having Lookouts during specific training 
activities.
    All personnel standing watch on the bridge, Commanding Officers, 
Executive Officers, maritime patrol aircraft aircrews, anti-submarine 
warfare helicopter crews, civilian equivalents, and Lookouts will 
successfully complete the United States Navy Marine Species Awareness 
Training prior to standing watch or serving as a Lookout. Additional 
details on the Navy's Marine Species Awareness Training can be found in 
the GOA DSEIS/OEIS. The Navy proposes to use one or more Lookouts 
during the training activities described below, which are organized by 
stressor category.
Non-Impulsive Sound

Hull Mounted Mid-Frequency Active Sonar

    The Navy's current Lookout mitigation measures during training 
activities involving hull-mounted MFAS include requirements such as the 
number of personnel on watch and the manner in which personnel are to 
visually search the area in the vicinity of the ongoing activity.
    The Navy is proposing to maintain the number of Lookouts currently 
implemented for ships using hull-mounted MFAS. Ships using hull-mounted 
MFAS sources associated with ASW activities at sea (with the exception 
of ships less than 65 ft. [20 m] in length, which are minimally manned) 
will have two Lookouts at the forward position. While using hull-
mounted MFAS sources underway, vessels less than 65 ft. [20 m] in 
length and ships that are minimally manned will have one Lookout at the 
forward position due to space and manning restrictions.

High-Frequency and Non-Hull-Mounted Mid-Frequency Active Sonar

    The Navy currently conducts activities using high-frequency and 
non-hull-mounted MFAS in the Study Area. Non-hull-mounted MFAS training 
activities include the use of aircraft deployed sonobuoys, helicopter 
dipping sonar, and submarine sonar. During those activities, the Navy 
employs the following mitigation measures regarding Lookout procedures:
     Navy aircraft participating in exercises at sea shall 
conduct and maintain, when operationally feasible and safe, 
surveillance for marine species of concern as long as it does not 
violate safety constraints or interfere with the accomplishment of 
primary operational duties.
     Helicopters shall observe/survey the vicinity of an ASW 
training event for 10 minutes before the first deployment of active 
(dipping) sonar in the water.
    The Navy is proposing to continue using the number of Lookouts 
(one) currently implemented for aircraft conducting non-hull-mounted 
MFA sonar activities.
    Mitigation measures do not currently exist for other high-frequency 
active sonar activities associated with ASW, or for new platforms; 
therefore, the Navy is proposing to add a new Lookout and other 
measures for these activities and on these platforms when conducted in 
the Study Area. The recommended measure is provided below.
    The Navy will have one Lookout on ships conducting high-frequency 
or non-hull mounted mid-frequency active sonar activities associated 
with ASW activities at sea.
Explosives and Impulsive Sound

Improved Extended Echo Ranging Sonobuoys

    The Navy is not proposing use of Improved Extended Echo Ranging 
Sonobuoys during the GOA TMAA training activities.

Explosive Signal Underwater Sound Buoys Using >0.5-2.5 Pound Net 
Explosive Weight

    Lookout measures do not currently exist for explosive signal 
underwater sound (SUS) buoy activities using >0.5-2.5 pound (lb.) net 
explosive weight (NEW). The Navy is proposing to add this measure. 
Aircraft conducting SUS activities using >0.5-2.5 lb. NEW will have one 
Lookout.

Gunnery Exercises--Small-, Medium-, and Large-Caliber Using a Surface 
Target

    Currently, the Navy employs the following Lookout procedures during 
gunnery exercises:
     From the intended firing position, trained Lookouts shall 
survey the mitigation zone for marine mammals prior to commencement and 
during the exercise as long as practicable.
     If applicable, target towing vessels shall maintain a 
Lookout. If a marine mammal is sighted in the vicinity of the exercise, 
the tow vessel shall immediately notify the firing vessel in order to 
secure gunnery firing until the area is clear.
    The Navy is proposing to continue using the Lookout procedures 
currently implemented for this activity. The Navy will have one Lookout 
on the vessel or aircraft conducting small-, medium-, or large-caliber 
gunnery exercises against a surface target. Towing vessels, if 
applicable, shall also maintain one Lookout.

Missile Exercises Using a Surface Target

    Currently, the Navy employs the following Lookout procedures during 
missile exercises:
     Aircraft shall visually survey the target area for marine 
mammals. Visual inspection of the target area shall be made by flying 
at 1,500 ft. (457 m) or lower, if safe to do so, and at slowest safe 
speed.

[[Page 9980]]

     Firing or range clearance aircraft must be able to 
actually see ordnance impact areas.
    The Navy is proposing to continue using the Lookout procedures 
currently implemented for this activity. When aircraft are conducting 
missile exercises against a surface target, the Navy will have one 
Lookout positioned in an aircraft.

Bombing Exercises (Explosive)

    Currently, the Navy employs the following Lookout procedures during 
bombing exercises:
     If surface vessels are involved, Lookouts shall survey for 
floating kelp and marine mammals.
     Aircraft shall visually survey the target and buffer zone 
for marine mammals prior to and during the exercise. The survey of the 
impact area shall be made by flying at 1,500 ft. (460 m) or lower, if 
safe to do so, and at the slowest safe speed. Release of ordnance 
through cloud cover is prohibited: Aircraft must be able to actually 
see ordnance impact areas. Survey aircraft should employ most effective 
search tactics and capabilities.
    The Navy is proposing to (1) continue implementing the current 
measures for bombing exercises, and (2) clarify the number of Lookouts 
currently implemented for this activity. The Navy will have one Lookout 
positioned in an aircraft conducting bombing exercises, and trained 
Lookouts in any surface vessels involved.

Weapons Firing Noise During Gunnery Exercises

    The Navy is proposing to continue using the number of Lookouts 
currently implemented for gunnery exercises. The Navy will have one 
Lookout on the ship conducting explosive and non-explosive gunnery 
exercises. This may be the same Lookout described for Gunnery 
Exercises--Small-, Medium-, and Large-Caliber Using a Surface Target 
when that activity is conducted from a ship against a surface target.

Sinking Exercises

    The Navy is proposing to continue using the number of Lookouts 
currently implemented for this activity. The Navy will have two 
Lookouts (one positioned in an aircraft and one on a vessel) during 
sinking exercises.
Physical Disturbance and Strike

Vessels

    Currently, the Navy employs the following Lookout procedures to 
avoid physical disturbance and strike of marine mammals during at-sea 
training:
     While underway, surface vessels shall have at least two 
Lookouts with binoculars; surfaced submarines shall have at least one 
Lookout with binoculars. Lookouts already posted for safety of 
navigation and man-overboard precautions may be used to fill this 
requirement. As part of their regular duties, Lookouts will watch for 
and report to the Officer of the Deck the presence of marine mammals.
    Consistent with other ongoing Navy Phase 2 training and testing 
(NWTT, MITT, AFTT, HSTT), the Navy is proposing to revise the 
mitigation measures for this activity as follows: While underway, 
vessels will have a minimum of one Lookout.
Non-Explosive Practice Munitions

Gunnery Exercises--Small-, Medium-, and Large-Caliber Using a Surface 
Target

    Currently, the Navy employs the same mitigation measures for non-
explosive practice munitions--small-, medium-, and large-caliber 
gunnery exercises--as described above for Gunnery Exercises--Small-, 
Medium-, and Large-Caliber Using a Surface Target.
    The Navy is proposing to continue using the number of Lookouts 
currently implemented for these activities. The Navy will have one 
Lookout during activities involving non-explosive practice munitions 
(e.g., small-, medium-, and large-caliber gunnery exercises) against a 
surface target.

Missile Exercises Using a Surface Target

    Currently, the Navy employs the same mitigation measures for non-
explosive missile exercises (including rockets) using a surface target 
as described for Missile Exercises Using a Surface Target (explosive).
    The Navy is proposing to continue using the number of Lookouts 
currently implemented for these activities. When aircraft are 
conducting non-explosive missile exercises (including exercises using 
rockets) against a surface target, the Navy will have one Lookout 
positioned in an aircraft.

Bombing Exercises

    Currently, the Navy employs the same mitigation measures for non-
explosive bombing exercises as described for Bombing Exercises 
(Explosive).
    The Navy is proposing to continue using the same Lookout procedures 
currently implemented for these activities. The Navy will have one 
Lookout positioned in an aircraft during non-explosive bombing 
exercises, and trained Lookouts in any surface vessels involved.

Mitigation Zones

    The Navy proposes to use mitigation zones to reduce the potential 
impacts to marine mammals from training activities. Mitigation zones 
are measured as the radius from a source. Unique to each activity 
category, each radius represents a distance that the Navy will visually 
observe to help reduce injury to marine species. Visual detections of 
applicable marine species will be communicated immediately to the 
appropriate watch station for information dissemination and appropriate 
action. If the presence of marine mammals is detected acoustically, 
Lookouts posted in aircraft and on surface vessels will increase the 
vigilance of their visual surveillance. As a reference, aerial surveys 
are typically made by flying at 1,500 ft. (457 m) altitude or lower at 
the slowest safe speed.
    Many of the proposed activities have mitigation measures that are 
currently being implemented, as required by previous environmental 
documents or consultations. Most of the current mitigation zones for 
activities that involve the use of impulsive and non-impulsive sources 
were originally designed to reduce the potential for onset of TTS. For 
the GOA DSEIS/OEIS and the LOA application, the Navy updated the 
acoustic propagation modeling to incorporate updated hearing threshold 
metrics (i.e., upper and lower frequency limits), updated density data 
for marine mammals, and factors such as an animal's likely presence at 
various depths. An explanation of the acoustic propagation modeling 
process can be found in the Determination of Acoustic Effects on Marine 
Mammals for the Gulf of Alaska Training Supplemental Environmental 
Impact Statement/Overseas Environmental Impact Statement technical 
report (Marine Species Modeling Team, 2014).
    As a result of the updates to the acoustic propagation modeling, in 
some cases the ranges to onset of TTS effects are much larger than 
previous model outputs. Due to the ineffectiveness and unacceptable 
operational impacts associated with mitigating these large areas, the 
Navy is unable to mitigate for onset of TTS for every activity. In this 
GOA TMAA analysis, the Navy developed each recommended mitigation zone 
to avoid or reduce the potential for onset PTS, out to the predicted 
maximum range. In some cases where the ranges to effects are smaller 
than previous models estimated, the mitigation zones were adjusted 
accordingly to provide consistency

[[Page 9981]]

across the measures. Mitigating to the predicted maximum range to PTS 
consequently also mitigates to the predicted maximum range to onset 
mortality (1 percent mortality), onset slight lung injury, and onset 
slight gastrointestinal tract injury, since the maximum range to 
effects for these criteria are shorter than for PTS. Furthermore, in 
most cases, the predicted maximum range to PTS also consequently covers 
the predicted average range to TTS. Table 8 summarizes the predicted 
average range to TTS, average range to PTS, maximum range to PTS, and 
recommended mitigation zone for each activity category, based on the 
Navy's acoustic propagation modeling results.
    The activity-specific mitigation zones are based on the longest 
range for all the functional hearing groups. The mitigation zone for a 
majority of activities is driven by either the high-frequency cetaceans 
or the sea turtles functional hearing groups. Therefore, the mitigation 
zones are even more protective for the remaining functional hearing 
groups (i.e., low-frequency cetaceans, mid-frequency cetaceans, and 
pinnipeds), and likely cover a larger portion of the potential range to 
onset of TTS.
    This evaluation includes explosive ranges to TTS and the onset of 
auditory injury, non-auditory injury, slight lung injury, and 
mortality. For every source proposed for use by the Navy, the 
recommended mitigation zones included in Table 8 exceed each of these 
ranges. In some instances, the Navy recommends mitigation zones that 
are larger or smaller than the predicted maximum range to PTS based on 
the effectiveness and operational assessments. The recommended 
mitigation zones and their associated assessments are provided 
throughout the remainder of this section. The recommended measures are 
either currently implemented, are modifications of current measures, or 
are new measures.
    For some activities specified throughout the remainder of this 
section, Lookouts may be required to observe for concentrations of 
detached floating vegetation (Sargassum or kelp paddies), which are 
indicators of potential marine mammal presence within the mitigation 
zone. Those specified activities will not commence if floating 
vegetation (Sargassum or kelp paddies) is observed within the 
mitigation zone prior to the initial start of the activity. If floating 
vegetation is observed prior to the initial start of the activity, the 
activity will be relocated to an area where no floating vegetation is 
observed. Training will not cease as a result of indicators entering 
the mitigation zone after activities have commenced. This measure is 
intended only for floating vegetation detached from the seafloor.

                            Table 8--Predicted Ranges to Effects and Recommended Mitigation Zones for Each Activity Category
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                      Representative source    Predicted (longest)    Predicted (longest)     Predicted maximum         Recommended
         Activity category                  (bin) \1\         average range to TTS    average range to PTS       range to PTS         mitigation zone
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Non-Impulse Sound
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hull-Mounted Mid[dash]Frequency      SQS-53 ASW hull-        3,821 yd. (3.5 km) for  100 yd. (91 m) for     Not Applicable.......  6 dB power down at
 Active Sonar.                        mounted sonar (MF1).    one ping.               one ping.                                     1,000 yd. (914 m); 4
                                                                                                                                    dB power down at 500
                                                                                                                                    yd. (457 m); and
                                                                                                                                    shutdown at 200 yd.
                                                                                                                                    (183 m).
High-Frequency and Non[dash]Hull     AQS-22 ASW dipping      230 yd. (210 m) for     20 yd. (18 m) for one  Not applicable.......  200 yd. (183 m).
 Mounted Mid[dash]Frequency Active    sonar (MF4).            one ping.               ping.
 Sonar.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Explosive and Impulse Sound
--------------------------------------------------------------------------------------------------------------------------------------------------------
Signal Underwater Sound (SUS) buoys  Explosive sonobuoy      290 yd. (265 m).......  113 yd. (103 m)......  309 yd. (283 m)......  350 yd. (320 m).
 using > 0.5-2.5 lb. NEW.             (E3).
Gunnery Exercises--Small- and        40 mm projectile (E2).  190 yd. (174 m).......  83 yd. (76 m)........  182 yd. (167 m)......  200 yd. (183 m).
 Medium-Caliber (Surface Target).
Gunnery Exercises--Large-Caliber     5 in. projectiles (E5)  453 yd. (414 m).......  186 yd. (170 m)......  526 yd. (481 m)......  600 yd. (549 m).
 (Surface Target).
Missile Exercises (Including         Maverick missile (E9).  949 yd. (868 m).......  398 yd. (364 m)......  699 yd. (639 m)......  900 yd. (823 m).
 Rockets) up to 250 lb. NEW Using a
 Surface Target.
Missile Exercises up to 500 lb. NEW  Harpoon missile (E10).  1,832 yd. (1.7 km)....  731 yd. (668 m)......  1,883 yd. (1.7 km)...  2,000 yd. (1.8 km).
 (Surface Target).
Bombing Exercises..................  MK-84 2,000 lb. bomb    2,513 yd. (2.3 km)....  991 yd. (906 m)......  2,474 yd. (2.3 km)...  2,500 yd. (2.3
                                      (E12).                                                                                        km)\2\.
Sinking Exercises..................  Various up to MK-84     2,513 yd. (2.3 km)....  991 yd. (906 m)......  2,474 yd. (2.3 km)...  2.5 nm \(2)\.
                                      2,000 lb. bomb (E12).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This table does not provide an inclusive list of source bins; bins presented here represent the source bin with the largest range to effects within
  the given activity category.
\2\ Recommended mitigation zones are larger than the modeled injury zones to account for multiple types of sources or charges being used.
Notes: in = inches, km = kilometers, lb. = pounds, m = meters, nm = nautical miles, PTS = Permanent Threshold Shift, TTS = Temporary Threshold Shift,
  yd. = yards


[[Page 9982]]

Non-Impulsive Sound

Hull-Mounted Mid-Frequency Active Sonar

    The Navy is proposing to (1) continue implementing the current 
measures for MFAS and (2) to clarify the conditions needed to 
recommence an activity after a marine mammal has been detected.
    Activities that involve the use of hull-mounted MFA sonar will use 
Lookouts for visual observation from a ship immediately before and 
during the activity. Mitigation zones for these activities involve 
powering down the sonar by 6 dB when a marine mammal is sighted within 
1,000 yd. (914 m) of the sonar dome, and by an additional 4 dB when 
sighted within 500 yd. (457 m) from the source, for a total reduction 
of 10 dB. Active transmissions will cease if a marine mammal is sighted 
within 200 yd. (183 m). Active transmission will recommence if any one 
of the following conditions is met: (1) The animal is observed exiting 
the mitigation zone, (2) the animal is thought to have exited the 
mitigation zone based on its course and speed, (3) the mitigation zone 
has been clear from any additional sightings for a period of 30 
minutes, (4) the ship has transited more than 2,000 yd. (1.8 km) beyond 
the location of the last sighting, or (5) the ship concludes that 
dolphins are deliberately closing in on the ship to ride the ship's bow 
wave (and there are no other marine mammal sightings within the 
mitigation zone). Active transmission may resume when dolphins are bow 
riding because they are out of the main transmission axis of the active 
sonar while in the shallow-wave area of the ship bow.

High-Frequency and Non-Hull-Mounted Mid-Frequency Active Sonar

    Non-hull-mounted MFA sonar training activities include the use of 
aircraft deployed sonobuoys and helicopter dipping sonar. The Navy is 
proposing to: (1) Continue implementing the current mitigation measures 
for activities currently being executed, such as dipping sonar 
activities; (2) extend the implementation of its current mitigation to 
all other activities in this category; and (3) clarify the conditions 
needed to recommence an activity after a sighting. The recommended 
measures are provided below.
    Mitigation will include visual observation from a vessel or 
aircraft (with the exception of platforms operating at high altitudes) 
immediately before and during active transmission within a mitigation 
zone of 200 yd. (183 m) from the active sonar source. For activities 
involving helicopter deployed dipping sonar, visual observation will 
commence 10 minutes before the first deployment of active dipping 
sonar. Helicopter dipping and sonobuoy deployment will not begin if 
concentrations of floating vegetation (kelp paddies), are observed in 
the mitigation zone. If the source can be turned off during the 
activity, active transmission will cease if a marine mammal is sighted 
within the mitigation zone. Active transmission will recommence if any 
one of the following conditions is met: (1) The animal is observed 
exiting the mitigation zone, (2) the animal is thought to have exited 
the mitigation zone based on its course and speed, (3) the mitigation 
zone has been clear from any additional sightings for a period of 10 
minutes for an aircraft-deployed source, (4) the mitigation zone has 
been clear from any additional sightings for a period of 30 minutes for 
a vessel-deployed source, (5) the vessel or aircraft has repositioned 
itself more than 400 yd. (370 m) away from the location of the last 
sighting, or (6) the vessel concludes that dolphins are deliberately 
closing in to ride the vessel's bow wave (and there are no other marine 
mammal sightings within the mitigation zone).
Explosives and Impulsive Sound

Explosive Signal Underwater Sound Buoys Using >0.5-2.5 Pound Net 
Explosive Weight

    Mitigation measures do not currently exist for activities using 
explosive signal underwater sound (SUS) buoys.
    The Navy is proposing to add the following recommended measures. 
Mitigation will include pre-exercise aerial monitoring during 
deployment within a mitigation zone of 350 yd. (320 m) around an 
explosive SUS buoy. Explosive SUS buoys will not be deployed if 
concentrations of floating vegetation (kelp paddies) are observed in 
the mitigation zone (around the intended deployment location). SUS 
deployment will cease if a marine mammal is sighted within the 
mitigation zone. Deployment will recommence if any one of the following 
conditions is met: (1) The animal is observed exiting the mitigation 
zone, (2) the animal is thought to have exited the mitigation zone 
based on its course and speed, or (3) the mitigation zone has been 
clear from any additional sightings for a period of 10 minutes.
    Passive acoustic monitoring will also be conducted with Navy 
assets, such as sonobuoys, already participating in the activity. These 
assets would only detect vocalizing marine mammals within the frequency 
bands monitored by Navy personnel. Passive acoustic detections would 
not provide range or bearing to detected animals, and therefore cannot 
provide locations of these animals. Passive acoustic detections would 
be reported to Lookouts posted in aircraft in order to increase 
vigilance of their visual surveillance.

Gunnery Exercises--Small- and Medium-Caliber Using a Surface Target

    The Navy is proposing to (1) continue implementing the current 
mitigation measures for this activity, (2) clarify the conditions 
needed to recommence an activity after a sighting, and (3) add a 
requirement to visually observe for kelp paddies.
    Mitigation will include visual observation from a vessel or 
aircraft immediately before and during the exercise within a mitigation 
zone of 200 yd. (183 m) around the intended impact location. Vessels 
will observe the mitigation zone from the firing position. When 
aircraft are firing, the aircrew will maintain visual watch of the 
mitigation zone during the activity. The exercise will not commence if 
concentrations of floating vegetation (kelp paddies) are observed in 
the mitigation zone. Firing will cease if a marine mammal is sighted 
within the mitigation zone. Firing will recommence if any one of the 
following conditions is met: (1) The animal is observed exiting the 
mitigation zone, (2) the animal is thought to have exited the 
mitigation zone based on its course and speed, (3) the mitigation zone 
has been clear from any additional sightings for a period of 10 minutes 
for a firing aircraft, (4) the mitigation zone has been clear from any 
additional sightings for a period of 30 minutes for a firing ship, or 
(5) the intended target location has been repositioned more than 400 
yd. (366 m) away from the location of the last sighting.

Gunnery Exercises--Large-Caliber Explosive Rounds Using a Surface 
Target

    The Navy is proposing to (1) continue using the currently 
implemented mitigation zone measures for this activity, (2) clarify the 
conditions needed to recommence an activity after a sighting, and (3) 
implement a requirement to visually observe for kelp paddies. The 
recommended measures are provided below.
    Mitigation will include visual observation from a ship immediately 
before and during the exercise within a mitigation zone of 600 yd. (549 
m) around the intended impact location. Ships will observe the 
mitigation zone

[[Page 9983]]

from the firing position. The exercise will not commence if 
concentrations of floating vegetation (kelp paddies) are observed in 
the mitigation zone. Firing will cease if a marine mammal is sighted 
within the mitigation zone. Firing will recommence if any one of the 
following conditions is met: (1) The animal is observed exiting the 
mitigation zone, (2) the animal is thought to have exited the 
mitigation zone based on its course and speed, or (3) the mitigation 
zone has been clear from any additional sightings for a period of 30 
minutes.

Missile Exercises Up to 250 Pound Net Explosive Weight Using a Surface 
Target

    Currently, the Navy employs a mitigation zone of 1,800 yd. (1.6 km) 
for all missile exercises. Because missiles have a wide range of 
warhead strength, the Navy is recommending two mitigation zones; one 
for missiles with warheads 250 lb. NEW and less, and a larger 
mitigation zone for missiles with larger warheads. The Navy is 
proposing to (1) modify the mitigation measures currently implemented 
for missile exercises involving missiles with 250 lb. NEW and smaller 
warheads by reducing the mitigation zone from 1,800 yd. (1.6 km) to 900 
yd. (823 m). This new, reduced mitigation zone is a result of the most 
recent acoustic propogation modeling efforts (NAEMO) for the GOA TMAA 
and is based on a range to effect that is smaller than previously 
modeled for missile exercises using a surface target (as discussed 
below, the Navy is proposing to increase the mitigation zone for 
missiles with a NEW >250 lb.), (2) clarify the conditions needed to 
recommence an activity after a sighting, and (3) adopt the marine 
mammal mitigation zone size for floating vegetation for ease of 
implementation. The recommended measures are provided below.
    When aircraft are involved in the missile firing, mitigation will 
include visual observation by the aircrew or supporting aircraft prior 
to commencement of the activity within a mitigation zone of 900 yd. 
(823 m) around the deployed target. The exercise will not commence if 
concentrations of floating vegetation (kelp paddies) are observed in 
the mitigation zone. Firing will cease if a marine mammal is sighted 
within the mitigation zone. Firing will recommence if any one of the 
following conditions is met: (1) The animal is observed exiting the 
mitigation zone, (2) the animal is thought to have exited the 
mitigation zone based on its course and speed, or (3) the mitigation 
zone has been clear from any additional sightings for a period of 10 
minutes or 30 minutes (depending on aircraft type).

Missile Exercises 251-500 Pound Net Explosive Weight (Surface Target)

    Current mitigation measures apply to all missile exercises, 
regardless of the warhead size. The Navy proposes to add a mitigation 
zone that applies only to missiles with a NEW of 251 to 500 lb. The 
recommended measures are provided below.
    When aircraft are involved in the missile firing, mitigation will 
include visual observation by the aircrew prior to commencement of the 
activity within a mitigation zone of 2,000 yd. (1.8 km) around the 
intended impact location. The exercise will not commence if 
concentrations of floating vegetation (kelp paddies) are observed in 
the mitigation zone. Firing will cease if a marine mammal is sighted 
within the mitigation zone. Firing will recommence if any one of the 
following conditions is met: (1) The animal is observed exiting the 
mitigation zone, (2) the animal is thought to have exited the 
mitigation zone based on its course and speed, or (3) the mitigation 
zone has been clear from any additional sightings for a period of 10 
minutes or 30 minutes (depending on aircraft type).

Bombing Exercises

    Currently, the Navy employs the following mitigation zone 
procedures during bombing exercises:
     Ordnance shall not be targeted to impact within 1,000 yd. 
(914 m) of known or observed floating kelp or marine mammals.
     A 1,000 yd. (914 m) radius mitigation zone shall be 
established around the intended target.
     The exercise will be conducted only if marine mammals are 
not visible within the mitigation zone.
    The Navy is proposing to (1) maintain the existing mitigation zone 
to be used for non-explosive bombing activities, (2) revise the 
mitigation zone procedures to account for predicted ranges to impacts 
to marine species when high explosive bombs are used, (3) clarify the 
conditions needed to recommence an activity after a sighting, and (4) 
add a requirement to visually observe for kelp paddies.
    Mitigation will include visual observation from the aircraft 
immediately before the exercise and during target approach within a 
mitigation zone of 2,500 yd. (2.3 km) around the intended impact 
location for explosive bombs and 1,000 yd. (920 m) for non-explosive 
bombs. The exercise will not commence if concentrations of floating 
vegetation (kelp paddies) are observed in the mitigation zone. Bombing 
will cease if a marine mammal is sighted within the mitigation zone. 
Bombing will recommence if any one of the following conditions is met: 
(1) The animal is observed exiting the mitigation zone, (2) the animal 
is thought to have exited the mitigation zone based on its course and 
speed, or (3) the mitigation zone has been clear from any additional 
sightings for a period of 10 minutes.

Sinking Exercises

    The Navy is proposing to (1) modify the mitigation measures 
currently implemented for this activity by increasing the mitigation 
zone from 2.0 nm to 2.5 nm, (2) clarify the conditions needed to 
recommence an activity after a sighting, (3) add a requirement to 
visually observe for kelp paddies, and (4) adopt the marine mammal and 
sea turtle mitigation zone size for concentrations of floating 
vegetation and aggregations of jellyfish for ease of implementation. 
The recommended measures are provided below.
    Mitigation will include visual observation within a mitigation zone 
of 2.5 nm around the target ship hulk. Sinking exercises will include 
aerial observation beginning 90 minutes before the first firing, visual 
observations from vessels throughout the duration of the exercise, and 
both aerial and vessel observation immediately after any planned or 
unplanned breaks in weapons firing of longer than 2 hours. Prior to 
conducting the exercise, the Navy will review remotely sensed sea 
surface temperature and sea surface height maps to aid in deciding 
where to release the target ship hulk.
    The Navy will also monitor using passive acoustics during the 
exercise. Passive acoustic monitoring would be conducted with Navy 
assets, such as passive ships sonar systems or sonobuoys, already 
participating in the activity. These assets would only detect 
vocalizing marine mammals within the frequency bands monitored by Navy 
personnel. Passive acoustic detections would not provide range or 
bearing to detected animals, and therefore cannot provide locations of 
these animals. Passive acoustic detections would be reported to 
Lookouts posted in aircraft and on vessels in order to increase 
vigilance of their visual surveillance. Lookouts will also increase 
observation vigilance before the use of torpedoes or unguided ordnance 
with a NEW of 500 lb. or greater, or if the Beaufort sea state is a 4 
or above.
    The exercise will not commence if concentrations of floating 
vegetation (kelp paddies) are observed in the

[[Page 9984]]

mitigation zone. The exercise will cease if a marine mammal, sea 
turtle, or aggregation of jellyfish is sighted within the mitigation 
zone. The exercise will recommence if any one of the following 
conditions is met: (1) The animal is observed exiting the mitigation 
zone, (2) the animal is thought to have exited the mitigation zone 
based on a determination of its course and speed and the relative 
motion between the animal and the source, or (3) the mitigation zone 
has been clear from any additional sightings for a period of 30 
minutes. Upon sinking the vessel, the Navy will conduct post-exercise 
visual surveillance of the mitigation zone for 2 hours (or until 
sunset, whichever comes first).

Weapons Firing Noise During Gunnery Exercises--Large-Caliber

    The Navy currently has no mitigation zone procedures for this 
activity in the Study Area.
    The Navy is proposing to adopt measures currently used during Navy 
gunnery exercises in other ranges outside of the Study Area. For all 
explosive and non-explosive large-caliber gunnery exercises conducted 
from a ship, mitigation will include visual observation immediately 
before and during the exercise within a mitigation zone of 70 yd. (46 
m) within 30 degrees on either side of the gun target line on the 
firing side. The exercise will not commence if concentrations of 
floating vegetation (kelp paddies) are observed in the mitigation zone. 
Firing will cease if a marine mammal is sighted within the mitigation 
zone. Firing will recommence if any one of the following conditions is 
met: (1) The animal is observed exiting the mitigation zone, (2) the 
animal is thought to have exited the mitigation zone based on its 
course and speed, (3) the mitigation zone has been clear from any 
additional sightings for a period of 30 minutes, or (4) the vessel has 
repositioned itself more than 140 yd. (128 m) away from the location of 
the last sighting.
Physical Disturbance and Strike

Vessels

    The Navy's current measures to mitigate potential impacts to marine 
mammals from vessel and in-water device strikes during training 
activities are provided below:
     Naval vessels shall maneuver to keep at least 500 yd. (457 
m) away from any observed whale in the vessel's path and avoid 
approaching whales head-on. These requirements do not apply if a 
vessel's safety is threatened, such as when change of course will 
create an imminent and serious threat to a person, vessel, or aircraft, 
and to the extent vessels are restricted in their ability to maneuver. 
Restricted maneuverability includes, but is not limited to, situations 
when vessels are engaged in dredging, submerged activities, launching 
and recovering aircraft or landing craft, minesweeping activities, 
replenishment while underway and towing activities that severely 
restrict a vessel's ability to deviate course.
     Vessels will take reasonable steps to alert other vessels 
in the vicinity of the whale. Given rapid swimming speeds and 
maneuverability of many dolphin species, naval vessels would maintain 
normal course and speed on sighting dolphins unless some condition 
indicated a need for the vessel to maneuver.

The Navy is proposing to continue to use the 500 yd. (457 m) mitigation 
zone currently established for whales, and to implement a 200 yd. (183 
m) mitigation zone for all other marine mammals. Vessels will avoid 
approaching marine mammals head on and will maneuver to maintain a 
mitigation zone of 500 yd. (457 m) around observed whales and 200 yd. 
(183 m) around all other marine mammals (except bow-riding dolphins), 
providing it is safe to do so. The Navy is clarifying its existing 
speed protocol; while in transit, Navy vessels shall be alert at all 
times, use extreme caution, and proceed at a ``safe speed'' so that the 
vessel can take proper and effective action to avoid a collision with 
any sighted object or disturbance, including any marine mammal or sea 
turtle, and can be stopped within a distance appropriate to the 
prevailing circumstances and conditions.

Towed In-Water Devices

    The Navy currently has no mitigation zone procedures for this 
activity in the Study Area.
    The Navy is proposing to adopt measures currently used in other 
ranges outside of the Study Area during activities involving towed in-
water devices. The Navy will ensure that towed in-water devices being 
towed from manned platforms avoid coming within a mitigation zone of 
250 yd. (229 m) around any observed marine mammal, providing it is safe 
to do so.
Non-Explosive Practice Munitions

Gunnery Exercises--Small-, Medium-, and Large-Caliber Using a Surface 
Target

    Currently, the Navy employs the same mitigation measures for non-
explosive gunnery exercises as described above for Gunnery Exercises--
Small-, Medium-, and Large-Caliber Using a Surface Target.
    The Navy is proposing to (1) continue using the mitigation measures 
currently implemented for this activity, and (2) clarify the conditions 
needed to recommence an activity after a sighting. The recommended 
measures are provided below.
    Mitigation will include visual observation from a vessel or 
aircraft immediately before and during the exercise within a mitigation 
zone of 200 yd. (183 m) around the intended impact location. The 
exercise will not commence if concentrations of floating vegetation 
(kelp paddies) are observed in the mitigation zone. Firing will cease 
if a marine mammal is sighted within the mitigation zone. Firing will 
recommence if any one of the following conditions is met: (1) The 
animal is observed exiting the mitigation zone, (2) the animal is 
thought to have exited the mitigation zone based on its course and 
speed, (3) the mitigation zone has been clear from any additional 
sightings for a period of 10 minutes for a firing aircraft, (4) the 
mitigation zone has been clear from any additional sightings for a 
period of 30 minutes for a firing ship, or (5) the intended target 
location has been repositioned more than 400 yd. (366 m) away from the 
location of the last sighting.

Bombing Exercises

    The Navy is proposing to continue using the mitigation measures 
currently implemented for this activity. The recommended measure 
includes clarification of a post-sighting activity recommencement 
criterion.
    Mitigation will include visual observation from the aircraft 
immediately before the exercise and during target approach within a 
mitigation zone of 1,000 yd. (914 m) around the intended impact 
location. The exercise will not commence if concentrations of floating 
vegetation (kelp paddies) are observed in the mitigation zone. Bombing 
will cease if a marine mammal is sighted within the mitigation zone. 
Bombing will recommence if any one of the following conditions is met: 
(1) The animal is observed exiting the mitigation zone, (2) the animal 
is thought to have exited the mitigation zone based on its course and 
speed, or (3) the mitigation zone has been clear from any additional 
sightings for a period of 10 minutes.

Missile Exercises (Including Rockets) Using a Surface Target

    The Navy is proposing to (1) modify the mitigation measures 
currently

[[Page 9985]]

implemented for this activity by reducing the mitigation zone from 
1,800 yd. (1.6 km) to 900 yd. (823 m), (2) clarify the conditions 
needed to recommence an activity after a sighting, (3) adopt the marine 
mammal and sea turtle mitigation zone size for floating vegetation for 
ease of implementation, and (4) modify the platform of observation to 
eliminate the requirement to observe when ships are firing. The 
recommended measures are provided below.
    When aircraft are firing, mitigation will include visual 
observation by the aircrew or supporting aircraft prior to commencement 
of the activity within a mitigation zone of 900 yd. (823 m) around the 
deployed target. The exercise will not commence if concentrations of 
floating vegetation (kelp paddies) are observed in the mitigation zone. 
Firing will cease if a marine mammal is sighted within the mitigation 
zone. Firing will recommence if any one of the following conditions is 
met: (1) The animal is observed exiting the mitigation zone, (2) the 
animal is thought to have exited the mitigation zone based on a 
determination of its course and speed and the relative motion between 
the animal and the source, or (3) the mitigation zone has been clear 
from any additional sightings for a period of 10 minutes or 30 minutes 
(depending on aircraft type).

Consideration of Time/Area Limitations

    The Navy's and NMFS' analysis of effects to marine mammals 
considers emergent science regarding locations where cetaceans are 
known to engage in specific activities (e.g., feeding, breeding/
calving, or migration) at certain times of the year that are important 
to individual animals as well as populations of marine mammals (see 
discussion in Van Parijs, 2015). Where data were available, Van Parijs 
(2015) identified areas that are important in this way and named the 
areas Biologically Important Areas (BIAs). It is important to note that 
the BIAs were not meant to define exclusionary zones, nor were they 
meant to be locations that serve as sanctuaries from human activity, or 
areas analogous to marine protected areas (see Ferguson et al. (2015a) 
regarding the envisioned purpose for the BIA designations). The 
delineation of BIAs does not have direct or immediate regulatory 
consequences, although it is appropriate to consider them as part of 
the body of science that may inform mitigation decisions, depending on 
the circumstances. The intention was that the BIAs would serve as 
resource management tools and that they be considered along with any 
new information as well as, ``existing density estimates, range-wide 
distribution data, information on population trends and life history 
parameters, known threats to the population, and other relevant 
information'' (Van Parijs, 2015).
    The Navy and NMFS have supported and will continue to support the 
Cetacean and Sound Mapping project, including representation on the 
Cetacean Density and distribution Working Group (CetMap), which 
informed NMFS' identification of BIAs. The same marine mammal density 
data present in the Navy's Marine Species Density Database Technical 
Report (U.S. Department of the Navy, 2014) and used in the analysis for 
the GOA SEIS/OEIS was used in the development of BIAs. The final 
products, including the Gulf of Alaska BIAs, from this mapping effort 
were completed and published in March 2015 (Aquatic Mammals, 2015; 
Calambokidis et al., 2015; Ferguson et al., 2015a, 2015b; Van Parijs, 
2015). 131 BIAs for 24 marine mammal species, stocks, or populations in 
seven regions within U.S. waters were identified (Ferguson et al., 
2015a). BIAs have been identified in the Gulf of Alaska in the vicinity 
of the GOA TMAA Study Area and include migratory and feeding BIAs for 
gray whale and North Pacific right whale, respectively. However, the 
degree of overlap between these BIAs and the Study area is negligible 
geographically. NMFS' recognition of an area as biologically important 
for some species activity is not equivalent to designation of critical 
habitat under the Endangered Species Act. Furthermore, the BIAs 
identified by NMFS in and around the Study Area do not represent the 
totality of important habitat throughout the marine mammals' full 
range.
    NMFS' Office of Protected Resources routinely considers available 
information about marine mammal habitat use to inform discussions with 
applicants regarding potential spatio-temporal limitations on their 
activities that might help effect the least practicable adverse impact 
on species or stocks and their habitat. BIAs are useful tools for 
planning and impact assessments and are being provided to the public 
via this Web site: www.cetsound.noaa.gov. While these BIAs are useful 
tools for analysts, any decisions regarding protective measures based 
on these areas must go through the normal MMPA evaluation process (or 
any other statutory process that the BIAs are used to inform); the 
identification of a BIA does not pre-suppose any specific management 
decision associated with those areas, nor does it have direct or 
immediate regulatory consequences. NMFS and the Navy have discussed the 
BIAs listed above, what Navy activities take place in these areas (in 
the context of what their effects on marine mammals might be or whether 
additional mitigation is necessary), and what measures could be 
implemented to reduce impacts in these areas (in the context of their 
potential to reduce marine mammal impacts and their practicability). An 
assessment of the potential spatio-temporal and activity overlap of 
Navy training activities with the Gulf of Alaska BIAs listed above is 
included below and in Chapter 3.8 of the GOA DSEIS/OEIS. In addition, 
in the Group and Species-Specific Analysis section of this proposed 
rule NMFS has preliminarily assessed the potential effects of Navy 
training on the ability of gray whale and North Pacific right whale to 
engage in those activities for which the BIAs have been identified 
(migratory and feeding). As we learn more about marine mammal density, 
distribution, and habitat use (and the BIAs are updated), NMFS and the 
Navy will continue to reevaluate appropriate time-area measures through 
the Adaptive Management process outlined in these regulations.
    North Pacific Right Whale Feeding Area--The NMFS-identified feeding 
area for North Pacific right whales (see Ferguson et al., 2015b) 
overlaps slightly with the GOA TMAA's southwestern corner. This feeding 
area is applicable from June to September so there is temporal overlap 
with the proposed Navy training but there is minimal (<1 percent) 
spatial overlap between this feeding area and the GOA TMAA (see Figure 
3.8-2 of the GOA DSEIS/OEIS).
    Given their current extremely low population numbers and the 
general lack of sightings in the Gulf of Alaska, the occurrence of 
right whales in the GOA TMAA is considered rare. North Pacific right 
whales have not been visually detected in the GOA TMAA since at least 
the 1960s. The Quinn Seamount passive acoustic detections in summer 
2013 ([Scaron]irovi[cacute] et al., 2014) are the only known potential 
occurrence records of this species in the GOA TMAA in recent years.
    Grey Whale Migratory Area--The NMFS-identified migration area for 
gray whales, which was bounded by the extent of the continental shelf 
(as provided in Ferguson et al., 2015b), has slight (<1 percent) 
overlap with the GOA TMAA at its northernmost corner and western edge 
(see Ferguson et al., 2015b; See Figure 3.8-4 of the GOA DSEIS/OEIS). 
However, this migration area is applicable only between March to May 
(Spring) and November to

[[Page 9986]]

January (Fall) (see Aquatic Mammals, 2015). This NMFS-identified gray 
whale migration area would not be applicable during the months when 
training has historically occurred (June/July) and is not likely to 
have temporal overlap with most of the proposed timeframe (May to 
October; summer) for Navy training in the GOA TMAA. It is worth 
mentioning that the Navy's acoustic analysis did not predict any takes 
of gray whales in the GOA TMAA and NMFS is not authorizing any takes of 
this species (see Group and Species-Specific Analysis section later in 
this proposed rule).
    Potential Training Overlap with BIAs--It is very unlikely that Navy 
training would occur in these nearshore locations adjacent to the GOA 
TMAA boundary where the overlap with BIAs occurs. To ensure that the 
Navy is able to conduct realistic training, Navy units must maintain 
sufficient room to maneuver. Therefore, training activities will 
typically take place some distance away from an operating area boundary 
to ensure sufficient sea or air space is available for tactical 
maneuvers within an approved operating area such as the GOA TMAA. The 
Navy also does not typically train next to any limiting boundary 
because it precludes tactical consideration of the adjacent sea space 
and airspace beyond the boundary from being a potential threat axis 
during activities such as anti-submarine warfare training. It is also 
the case that Navy training activities will generally not be located 
where it is likely there would be interference from civilian vessels 
and aircraft that are not participating in the training activity. The 
nearshore boundary of the GOA TMAA is the location for multiple 
commercial vessel transit lanes, ship traffic, and low-altitude air 
routes, which all pass through the NMFS-identified feeding area and the 
identified migration area (see Figure 3.8-9 of the GOA DSEIS/OEIS). 
This level of civilian activity may otherwise conflict with Navy 
training activities if those Navy activities were located at that 
margin of the GOA TMAA and as a result such an area is generally 
avoided.
    In short, the corners of and edge of the GOA TMAA are seldom if 
ever a suitable location for sustained, realistic, and coordinated 
training using sonar and other active acoustic sources or explosives. 
The Navy has lookouts and mitigation measures in place to maneuver away 
from and around marine mammals, and Navy vessels and aircraft are no 
more likely to cause any impact to these species than any other non-
Navy vessels or aircraft in the area. The Navy's stand-off distance for 
vessels of 500 yd. (457 m) and mitigation procedures (see Proposed 
Mitigation) further reduce the potential that there would be any 
biologically meaningful effect to feeding or migration should animals 
be present and detected during a very unlikely Navy training event 
using sonar and other active acoustic sources or explosives in one of 
these overlapping NMFS-identified areas. Therefore, North Pacific right 
whales and gray whales in the NMFS-identified feeding or migration 
areas at these boundaries of the GOA TMAA are very unlikely to have 
their feeding or migration activities affected by Navy training 
activities using sonar and other active acoustic sources.
    Conclusion--Based on the likely locations for training in the GOA 
TMAA, the Navy and NMFS anticipate that proposed training activities 
would have very limited, if any, spatial or temporal overlap with the 
designated North Pacific right whale area or gray whale biologically 
important areas. Therefore, it is unlikely that Navy training would 
have any biologically meaningful effect on North Pacific right whale 
feeding behavior or gray whale migration behavior in these areas. 
Moreover, appropriate mitigation measures (as detailed in Proposed 
Mitigation above) would be implemented for any detected marine mammals 
and thus further reduce the potential for the feeding or migration 
activities to be affected.

Stranding Response Plan

    NMFS and the Navy developed a Stranding Response Plan for GOA TMAA 
in 2011 as part of the previous (2011-2016) incidental take 
authorization and rulemaking process for the Study Area. The Stranding 
Response Plan is specifically intended to outline the applicable 
requirements in the event that a marine mammal stranding is reported in 
the complexes during a major training exercise. NMFS considers all 
plausible causes within the course of a stranding investigation and 
this plan in no way presumes that any strandings are related to, or 
caused by, Navy training activities, absent a determination made during 
investigation. The plan is designed to address mitigation, monitoring, 
and compliance. The current Stranding Response Plan for the GOA TMAA is 
available for review at: http://www.nmfs.noaa.gov/pr/permits/goa_tmaa_stranding_protocol.pdf. NMFS and the Navy are currently 
updating the Stranding Response Plan for the GOA TMAA for 2016-2021 
training activities. The updated Stranding Response Plan will be 
finalized prior to the release of the final rule, and will be made 
available for review at: http://www.nmfs.noaa.gov/pr/permits/incidental/military.htm#navy_goa2021. In addition, modifications to the 
Stranding Response Plan may also be made through the adaptive 
management process.

Mitigation Conclusions

    NMFS has carefully evaluated the Navy's proposed mitigation 
measures--many of which were developed with NMFS' input during the 
first phase of Navy Training authorizations--and considered a broad 
range of other measures in the context of ensuring that NMFS prescribes 
the means of effecting the least practicable adverse impact on the 
affected marine mammal species and stocks and their habitat. Our 
evaluation of potential measures included consideration of the 
following factors in relation to one another: The manner in which, and 
the degree to which, the successful implementation of the mitigation 
measures is expected to reduce the likelihood and/or magnitude of 
adverse impacts to marine mammal species and stocks and their habitat; 
the proven or likely efficacy of the measures; and the practicability 
of the suite of measures for applicant implementation, including 
consideration of personnel safety, practicality of implementation, and 
impact on the effectiveness of the military readiness activity.
    Based on our evaluation of the Navy's proposed measures, as well as 
other measures considered by NMFS, NMFS has determined preliminarily 
that the Navy's proposed mitigation measures (especially when the 
adaptive management component is taken into consideration (see Adaptive 
Management, below)) are adequate 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, while also considering 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    The proposed rule comment period provides the public an opportunity 
to submit recommendations, views, and/or concerns regarding this action 
and the proposed mitigation measures. While NMFS has determined 
preliminarily that the Navy's proposed mitigation measures would affect 
the least practicable adverse impact on the affected species or stocks 
and their habitat, NMFS will consider all public comments to help 
inform our final

[[Page 9987]]

decision. Consequently, the proposed mitigation measures may be 
refined, modified, removed, or added to prior to the issuance of the 
final rule based on public comments received, and where appropriate, 
further analysis of any additional mitigation measures.

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 and of the level of taking or impacts on populations of marine 
mammals that are expected to be present.

Integrated Comprehensive Monitoring Program (ICMP)

    The Navy's ICMP is intended to coordinate monitoring efforts across 
all regions and to allocate the most appropriate level and type of 
effort for each range complex based on a set of standardized 
objectives, and in acknowledgement of regional expertise and resource 
availability. The ICMP is designed to be a flexible, scalable, and 
adaptable through the adaptive management and strategic planning 
processes to periodically assess progress and reevaluate objectives. 
Although the ICMP does not specify actual monitoring field work or 
projects, it does establish top-level goals that have been developed in 
coordination with NMFS. As the ICMP is implemented, detailed and 
specific studies will be developed which support the Navy's top-level 
monitoring goals. In essence, the ICMP directs that monitoring 
activities relating to the effects of Navy training and testing 
activities on marine species should be designed to contribute towards 
one or more of the following top-level goals:
     An increase in our understanding of the likely occurrence 
of marine mammals and/or ESA-listed marine species in the vicinity of 
the action (i.e., presence, abundance, distribution, and/or density of 
species);
     An increase in our understanding of the nature, scope, or 
context of the likely exposure of marine mammals and/or ESA-listed 
species to any of the potential stressor(s) associated with the action 
(e.g., tonal and impulsive sound), through better understanding of one 
or more of the following: (1) The action and the environment in which 
it occurs (e.g., sound source characterization, propagation, and 
ambient noise levels); (2) the affected species (e.g., life history or 
dive patterns); (3) the likely co-occurrence of marine mammals and/or 
ESA-listed marine species with the action (in whole or part) associated 
with specific adverse effects, and/or; (4) the likely biological or 
behavioral context of exposure to the stressor for the marine mammal 
and/or ESA-listed marine species (e.g., age class of exposed animals or 
known pupping, calving or feeding areas);
     An increase in our understanding of how individual marine 
mammals or ESA-listed marine species respond (behaviorally or 
physiologically) to the specific stressors associated with the action 
(in specific contexts, where possible, e.g., at what distance or 
received level);
     An increase in our understanding of how anticipated 
individual responses, to individual stressors or anticipated 
combinations of stressors, may impact either: (1) The long-term fitness 
and survival of an individual; or (2) the population, species, or stock 
(e.g., through effects on annual rates of recruitment or survival);
     An increase in our understanding of the effectiveness of 
mitigation and monitoring measures;
     A better understanding and record of the manner in which 
the authorized entity complies with the ITA and Incidental Take 
Statement;
     An increase in the probability of detecting marine mammals 
(through improved technology or methods), both specifically within the 
safety zone (thus allowing for more effective implementation of the 
mitigation) and in general, to better achieve the above goals; and
     A reduction in the adverse impact of activities to the 
least practicable level, as defined in the MMPA.
    Monitoring would address the ICMP top-level goals through a 
collection of specific regional and ocean basin studies based on 
scientific objectives. Quantitative metrics of monitoring effort (e.g., 
20 days of aerial surveys) would not be a specific requirement. The 
adaptive management process and reporting requirements would serve as 
the basis for evaluating performance and compliance, primarily 
considering the quality of the work and results produced, as well as 
peer review and publications, and public dissemination of information, 
reports, and data. Details of the ICMP are available online (http://www.navymarinespeciesmonitoring. us/).

Strategic Planning Process for Marine Species Monitoring

    The Navy also developed the Strategic Planning Process for Marine 
Species Monitoring, which establishes the guidelines and processes 
necessary to develop, evaluate, and fund individual projects based on 
objective scientific study questions. The process uses an underlying 
framework designed around top-level goals, a conceptual framework 
incorporating a progression of knowledge, and in consultation with a 
Scientific Advisory Group and other regional experts. The Strategic 
Planning Process for Marine Species Monitoring would be used to set 
intermediate scientific objectives, identify potential species of 
interest at a regional scale, and evaluate and select specific 
monitoring projects to fund or continue supporting for a given fiscal 
year. This process would also address relative investments to different 
range complexes based on goals across all range complexes, and 
monitoring would leverage multiple techniques for data acquisition and 
analysis whenever possible. The Strategic Planning Process for Marine 
Species Monitoring is also available online (http://www.navymarinespeciesmonitoring navymarinespeciesmonitoring.us/).

Past and Current Monitoring in the Study Area

    NMFS has received multiple years' worth of annual exercise and 
monitoring reports addressing active sonar use and explosive 
detonations within the GOA TMAA and other Navy range complexes. The 
data and information contained in these reports have been considered in 
developing mitigation and monitoring measures for the proposed training 
activities within the Study Area. The Navy's annual exercise and 
monitoring reports may be viewed at: http://www.nmfs.noaa.gov/pr/permits/incidental/military.htm and http://www.navymarinespeciesmonitoring.us. NMFS has reviewed these reports and 
summarized the results, as related to marine mammal monitoring, below.
    1. The Navy has shown significant initiative in developing its 
marine species monitoring program and made considerable progress toward 
reaching goals and objectives of the ICMP.
    2. Observation data from watchstanders aboard navy vessels is 
generally useful to indicate the presence or absence of marine mammals 
within the mitigation zones (and sometimes beyond) and to document the 
implementation of mitigation measures, but does not provide useful 
species-specific information or behavioral data.

[[Page 9988]]

    3. Data gathered by experienced marine mammal observers can provide 
very valuable information at a level of detail not possible with 
watchstanders.
    4. Though it is by no means conclusive, it is worth noting that no 
instances of obvious behavioral disturbance have been observed by Navy 
watchstanders or experienced marine mammal observers conducting visual 
monitoring.
    5. Visual surveys generally provide suitable data for addressing 
questions of distribution and abundance of marine mammals, but are much 
less effective at providing information on movements and behavior, with 
a few notable exceptions where sightings are most frequent.
    6. Passive acoustics and animal tagging have significant potential 
for applications addressing animal movements and behavioral response to 
Navy training activities, but require a longer time horizon and heavy 
investment in analysis to produce relevant results.
    7. NMFS and the Navy should more carefully consider what and how 
information should be gathered by watchstanders during training 
exercises and monitoring events, as some reports contain different 
information, making cross-report comparisons difficult.
    This section is a summary of Navy-funded compliance monitoring in 
the GOA TMAA since 2011. Additional Navy-funded monitoring outside of 
and in addition to the Navy's commitments to NMFS is provided later in 
this section.
    Gulf of Alaska Study Area Monitoring, 2011-2015--During the LOA 
development process for the 2011 GOA FEIS/OEIS, the Navy and NMFS 
agreed that monitoring in the Gulf of Alaska should focus on augmenting 
existing baseline data, since regional data on species occurrence and 
density are extremely limited. There have been four reports to date 
covering work in the Gulf of Alaska (U.S. Department of the Navy, 
2011c, 2011d, 2012, 2013f). Collecting baseline data was deemed a 
priority prior to focusing on exercise monitoring and behavioral 
response as is now being done in other Navy OPAREAs and ranges. There 
have been no previous dedicated monitoring efforts during Navy training 
activities in the GOA TMAA with the exception of deployed HARPs.
    In July 2011, the Navy funded deployment of two long-term bottom-
mounted passive acoustic monitoring buoys by Scripps Institute of 
Oceanography. These HARPs were deployed southeast of Kenai Peninsula in 
the GOA TMAA with one on the shelf approximately 50 nm from land (in 
111 fathoms [203 m] depth) and on the shelf-break slope approximately 
100 nm from land (in 492 fathoms [900 m] depth). Intended to be 
collected annually, results from the first deployment (July 2011-May 
2012) included over 5,756 hours of passive acoustic data (Baumann-
Pickering et al. 2012b). Identification of marine mammal sounds 
included four baleen whale species (blue whales, fin whales, gray 
whales, and humpback whales) and at least six species of odontocetes 
(killer whale, sperm whale, Stejneger's beaked whale, Baird's beaked 
whale, Cuvier's beaked whale, and an unidentified porpoise presumed to 
be Dall's porpoise; Baumann-Pickering et al., 2012b). Researchers also 
noted the detection of anthropogenic sound from commercial shipping. 
There were no Navy activities or vessels in the area at any time during 
the recording period.
    Analysis of the passive acoustic detections made from May 2012 to 
June 2013 were presented in Baumann-Pickering et al. (2013), Debich et 
al. (2013), Debich et al. (2014), and the Navy's 2012, 2013, and 2014 
GOA TMAA annual monitoring report submitted to NMFS (U.S. Department of 
the Navy, 2012, 2013f, 2014d). Three baleen whale species were 
detected: Blue whales, fin whales, and humpback whales. No North 
Pacific right whale calls were detected at either site during this 
monitoring period. At least seven species of odontocetes were detected: 
Risso's dolphins, killer whales, sperm whales, Baird's beaked whales, 
Cuvier's beaked whales, Stejneger's beaked whales, and unidentified 
porpoises (likely Dall's porpoise). Focused analysis of beaked whale 
echolocation recordings were presented in Baumann-Pickering et al. 
(2013).
    As also presented in Debich et al. (2013) and U.S. Department of 
the Navy (2013f), broadband ship noise was found to be more common at 
the slope and Pratt Seamount monitoring sites within the GOA TMAA than 
at the nearshore (on shelf) site. Sonar (a variety of frequencies, most 
likely fathometers and fish-finders), were more common on the shelf and 
slope sites. Very few explosions were recorded at any of the three 
sites throughout the monitoring period. Origin of the few explosions 
detected are unknown, but there was no Navy explosive use in the GOA 
TMAA during this period, so these explosive-like events may be related 
to fisheries activity, lightning strikes, or some other unidentified 
source. There were no detections of Navy mid-frequency sonar use in the 
recordings (Debich et al. 2013, 2014; U.S. Department of the Navy 
2013f, 2014d). In September 2012, an additional HARP buoy was deployed 
at Pratt Seamount (near the east end of the GOA TMAA) and in June 2013 
two additional buoys were deployed in the GOA TMAA: One at the shelf-
break near the southwest corner of the GOA TMAA and one at Quinn 
Seamount (the approximate middle of the GOA TMAA's southeast boundary). 
This constitutes a total of five Navy-funded concurrent long-term 
passive acoustic monitoring packages present in the GOA TMAA through 
fall of 2014. Debich et al. (2013) reported the first detection of a 
North Pacific right whale at the Quinn Seamount site. Over two days 
between June and August 2013, the Quinn seamount HARP detected three 
hours of North Pacific right whale calls (Debich et al., 2014, 
[Scaron]irovi[cacute] et al., in press). Given the recording device 
location near the southwest border of the GOA TMAA, inability of the 
device as configured to determine call directionality, and likely 
signal propagation of several 10s of miles, it remains uncertain if the 
detected calls orginated within or outside of the GOA TMAA. Previous 
related Navy funded monitoring at multiple sites within the Study Area 
reported no North Pacific right whale detections (Baumann-Pickering et 
al., 2012b, Debich et al., 2013). Additional monitoring conducted in 
the GOA TMAA through spring 2015 included the deployment of five HARPs 
to detect marine mammals and anthropogenic sounds (Rice et al., 2015). 
Future monitoring will include varying numbers of HARPs or other 
passive acoustic technologies based on annual Adaptive Management 
discussions with NMFS (see U.S. Department of the Navy [2014d] for 
details in that regard).
    In the Gulf of Alaska, the Navy has also funded two previous marine 
mammal surveys to gather occurrence and density data. Although there 
was no regulatory requirement for the Navy to undertake either survey, 
the Navy funded the data collection to first support analysis of 
potential effects for the 2011 GOA FEIS/OEIS and again recently to 
support the current SEIS/OEIS. The first Navy-funded survey (GOALS) was 
conducted by NMFS in April 2009 (see Rone et al., 2009). Line-transect 
survey visual data was gathered to support distance sampling statistics 
and acoustic data were collected over a 10-day period both within and 
outside the GOA TMAA. This survey resulted in sightings of several 
species and allowed for the derivation of densities for fin and 
humpback whale that supplemented multiple previous survey efforts in 
the

[[Page 9989]]

vicinity (Rone et al., 2009). In summer 2013, the Navy funded an 
additional visual line-transect survey in the offshore waters of the 
Gulf of Alaska (Rone et al., 2014). The GOALS II survey was a 30-day 
visual line-transect survey supplemented by use of passive acoustics 
and was a follow-on effort to the previously Navy-funded GOALS survey 
in 2009. The primary objectives for the GOALS II survey were to acquire 
baseline data to increase understanding of the likely occurrence (i.e., 
presence, abundance, distribution and/or density of species) of beaked 
whales and ESA-listed marine mammals in the Gulf of Alaska. Specific 
research objectives were:
     Assess the abundance, spatial distribution and/or density 
of marine mammals, with a focus on beaked whales and ESA-listed 
cetacean species through visual line-transect surveys and passive 
acoustics using a towed hydrophone array and sonobuoys
     Increase knowledge of species' vocal repertoire by linking 
visual sightings to vocally active cetaceans, in order to improve the 
effectiveness of passive acoustic monitoring
     Attempt to photo-identify and biopsy sample individual 
whales opportunistically for analysis of population structure, genetics 
and habitat use
     Attempt to locate whales for opportunistic satellite 
tagging using visual and passive acoustic methodology in order to 
provide information on both large- and fine-scale movements and habitat 
use of cetaceans
    The Navy-funded GOALS II survey also sampled four distinct habitat 
areas (shelf, slope, offshore, and seamounts) which were partitioned 
into four strata. The survey design was intended to provide uniform 
coverage within the Gulf of Alaska. However, given the overall limited 
knowledge of beaked whales within the Gulf of Alaska, the survey was 
also designed to provide coverage of potential beaked whale habitat and 
resulted in 13 encounters with beaked whales numbering 67 individual 
animals (Rone et al., 2014). The following additional details are 
summarized from the presentation in Rone et al. (2014). The visual 
survey consisted of 4,504 km (2,431 nm) of `full-effort' and included 
349 km (188 nm) of `transit-effort.' There was an additional 375 km 
(202 nm) of `fog-effort' (transect and transit). Based on total effort, 
there were 802 sightings (1,998 individuals) identified to species, 
with an additional 162 sightings (228 individuals) of unidentified 
cetaceans and pinnipeds. Acoustic surveying was conducted round-the-
clock with a towed-hydrophone array for 6,304 km (3,997 nm) of line-
transect effort totaling 426 hours of `standard' monitoring, with an 
additional 374 km (202 nm) of ~30 hours of `non-standard' and `chase' 
effort. There were 379 acoustic detections and 267 localizations of 6 
identified cetacean species. Additionally, 186 acoustic sonobuoys were 
deployed with 7 identified cetacean species detected. Two satellite 
transmitter tags were deployed; a tag on a blue whale (B. musculus) 
transmitted for 9 days and a tag on a Baird's beaked whale (Berardius 
bairdii) transmitted for 15 days. Based on photo-identification 
matches, the tagged blue whale had been previously identified off Baja 
California, Mexico, in 2005. Photographs of five cetacean species were 
collected for photo-identification purposes: fin, humpback, blue, 
killer (Orcinus orca) and Baird's beaked whales. The estimates of 
abundance and density for five species were obtained for the first time 
for the central Gulf of Alaska. Overall, the Navy funded GOALS II 
survey provided one of the most comprehensive datasets on marine mammal 
occurrence, abundance, and distribution within that rarely surveyed 
area (Rone et al., 2014).
    NMFS has acknowledged that the Navy's GOA TMAA monitoring will 
enhance understanding of marine mammal vocalizations and distributions 
within the offshore waters of the Gulf of Alaska. Additionally, NMFS 
pointed out that information gained from the investigations associated 
with the Navy's monitoring may be used in the adaptive management of 
monitoring measures in subsequent NMFS authorizations, if appropriate 
and in consultation with NMFS. The Navy is committed to structuring the 
Navy-sponsored research and monitoring program to address both NMFS' 
regulatory requirements as part of any MMPA authorizations while at the 
same time making significant contributions to the greater body of 
marine mammal science (see U.S. Department of the Navy, 2013f).
    Pacific Northwest Cetacean Tagging--A Navy-funded effort in the 
Pacific Northwest is ongoing and involves attaching long-term satellite 
tracking tags to migrating gray whales off the coast of Oregon and 
northern California (U.S. Department of the Navy, 2013e). This study is 
being conducted by the University of Oregon and has also included 
tagging of other large whale species such as humpback whales, fin 
whales, and killer whales when encountered. This effort is not 
programmed, affiliated, or managed as part of the GOA TMAA monitoring, 
and is a separate regional project, but has provided information on 
marine mammals and their movements that has application to the Gulf of 
Alaska.
    In one effort between May 2010 and May 2013, satellite tracking 
tags were placed on three gray whales, 11 fin whales, five humpback 
whales, and two killer whales off the Washington coast (Schorr et al., 
2013). One tag on an Eastern North Pacific Offshore stock killer whale, 
in a pod encountered off Washington at Grays Harbor Canyon, remained 
attached and continued to transmit for approximately 3 months. In this 
period, the animal transited a distance of approximately 4,700 nm, 
which included time spent in the nearshore margins of the TMAA in the 
Gulf of Alaska where it would be considered part of the Offshore stock 
(for stock designations, see Muto and Angliss, 2015). In a second 
effort between 2012 and 2013, tags were attached to 11 Pacific Coast 
Feeding Group gray whales near Crescent City, California; in general, 
the tag-reported positions indicated these whales were moving southward 
at this time of year (Mate, 2013). The Navy's 2013 annual monitoring 
report for the Northwest Training and Testing Range contains the 
details of the findings from both research efforts described above 
(U.S. Department of the Navy, 2013e).

Proposed Monitoring for the GOA TMAA Study Area

    Based on NMFS-Navy meetings in June and October 2011, and the 
upcoming annual monitoring meeting scheduled for March 2016, future 
Navy compliance monitoring, including ongoing monitoring, will address 
ICMP top-level goals through a series of regional and ocean basin study 
questions with a prioritization and funding focus on species of 
interest as identified for each range complex. The ICMP will also 
address relative investments to different range complexes based on 
goals across all range complexes, and monitoring will leverage multiple 
techniques for data acquisition and analysis whenever possible.
    Within the GOA TMAA Study Area, the Navy's monitoring for GOA TMAA 
under this LOA authorization and concurrently in other areas of the 
Pacific Ocean will therefore be structured to address region-specific 
species-specific study questions in consultation with NMFS.
    The outcome of the March 2016 Navy-NMFS monitoring meeting, 
including any proposed monitoring during the period covered by this 
proposed rule

[[Page 9990]]

(2016-2021) will be discussed in the final rule. In addition, Navy 
monitoring projects proposed during the 2016-2021 GOA TMAA rulemaking 
period will be posted on the Navy's marine species monitoring Web site 
(http://www.navymarinespeciesmonitoring.us/regions/pacific/current-
projects/).

Ongoing Navy Research

    The U.S. Navy is one of the world's leading organizations in 
assessing the effects of human activities on the marine environment 
including marine mammals. From 2004 through 2013, the Navy has funded 
over $240M specifically for marine mammal research. Navy scientists 
work cooperatively with other government researchers and scientists, 
universities, industry, and non-governmental conservation organizations 
in collecting, evaluating, and modeling information on marine 
resources. They also develop approaches to ensure that these resources 
are minimally impacted by existing and future Navy operations. It is 
imperative that the Navy's R&D efforts related to marine mammals are 
conducted in an open, transparent manner with validated study needs and 
requirements. The goal of the Navy's R&D program is to enable 
collection and publication of scientifically valid research as well as 
development of techniques and tools for Navy, academic, and commercial 
use. Historically, R&D programs are funded and developed by the Navy's 
Chief of Naval Operations Energy and Environmental Readiness Division 
(OPNAV N45) and Office of Naval Research (ONR), Code 322 Marine Mammals 
and Biological Oceanography Program. The primary focus of these 
programs since the 1990s is on understanding the effects of sound on 
marine mammals, including physiological, behavioral, and ecological 
effects.
    ONR's current Marine Mammals and Biology Program thrusts include, 
but are not limited to: (1) monitoring and detection research, (2) 
integrated ecosystem research including sensor and tag development, (3) 
effects of sound on marine life (such as hearing, behavioral response 
studies, physiology [diving and stress], and PCAD), and (4) models and 
databases for environmental compliance.
    To manage some of the Navy's marine mammal research programmatic 
elements, OPNAV N45 developed in 2011 a new Living Marine Resources 
(LMR) Research and Development Program (http://www.lmr.navy.mil/). The 
goal of the LMR Research and Development Program is to identify and 
fill knowledge gaps and to demonstrate, validate, and integrate new 
processes and technologies to minimize potential effects to marine 
mammals and other marine resources. Key elements of the LMR program 
include:
     Providing science-based information to support Navy 
environmental effects assessments for research, development, 
acquisition, testing and evaluation as well as Fleet at-sea training, 
exercises, maintenance and support activities.
     Improving knowledge of the status and trends of marine 
species of concern and the ecosystems of which they are a part.
     Developing the scientific basis for the criteria and 
thresholds to measure the effects of Navy generated sound.
     Improving understanding of underwater sound and sound 
field characterization unique to assessing the biological consequences 
resulting from underwater sound (as opposed to tactical applications of 
underwater sound or propagation loss modeling for military 
communications or tactical applications).
     Developing technologies and methods to monitor and, where 
possible, mitigate biologically significant consequences to living 
marine resources resulting from naval activities, emphasizing those 
consequences that are most likely to be biologically significant.

Navy Research and Development

    Navy Funded--Both the LMR and ONR Research and Development Programs 
periodically fund projects within the Study Area. Some data and 
results, when available from these R&D projects, are typically 
summarized in the Navy's annual range complex Monitoring Reports that 
are currently submitted to the NMFS each year. In addition, the Navy's 
Range Complex monitoring during training and testing activities is 
coordinated with the R&D monitoring in a given region to leverage 
research objectives, assets, and studies where possible under the ICMP.
    The integration between the Navy's new LMR Research and Development 
Program and related range complex monitoring will continue and improve 
during this LOA application period with applicable results presented in 
GOA TMAA annual monitoring reports.
    Other National Department of Defense Funded Initiatives--Strategic 
Environmental Research and Development Program (SERDP) and 
Environmental Security Technology Certification Program (ESTCP) are the 
DoD's environmental research programs, harnessing the latest science 
and technology to improve environmental performance, reduce costs, and 
enhance and sustain mission capabilities. The Programs respond to 
environmental technology requirements that are common to all of the 
military Services, complementing the Services' research programs. SERDP 
and ESTCP promote partnerships and collaboration among academia, 
industry, the military Services, and other Federal agencies. They are 
independent programs managed from a joint office to coordinate the full 
spectrum of efforts, from basic and applied research to field 
demonstration and validation.

Adaptive Management

    The final regulations governing the take of marine mammals 
incidental to Navy training activities in the Study Area would contain 
an adaptive management component carried over from previous 
authorizations. Although better than 5 years ago, our understanding of 
the effects of Navy training and testing activities (e.g., MFAS/HFAS, 
underwater detonations) on marine mammals is still relatively limited, 
and yet the science in this field is evolving fairly quickly. These 
circumstances make the inclusion of an adaptive management component 
both valuable and necessary within the context of 5-year regulations 
for activities that have been associated with marine mammal mortality 
in certain circumstances and locations.
    The reporting requirements associated with this proposed rule are 
designed to provide NMFS with monitoring data from the previous year to 
allow NMFS to consider whether any changes are appropriate. NMFS and 
the Navy would meet to discuss the monitoring reports, Navy R&D 
developments, and current science and whether mitigation or monitoring 
modifications are appropriate. The use of adaptive management allows 
NMFS to consider new information from different sources to determine 
(with input from the Navy regarding practicability) on an annual or 
biennial basis if mitigation or monitoring measures should be modified 
(including additions or deletions). Mitigation measures could be 
modified if new data suggests that such modifications would have a 
reasonable likelihood of reducing adverse effects to marine mammals and 
if the measures are practicable.
    The following are some of the possible sources of applicable data 
to be considered through the adaptive management process: (1) Results 
from monitoring and exercises reports, as required by MMPA 
authorizations; (2) compiled results of Navy funded R&D

[[Page 9991]]

studies; (3) results from specific stranding investigations; (4) 
results from general marine mammal and sound research; and (5) any 
information which reveals that marine mammals may have been taken in a 
manner, extent, or number not authorized by these regulations or 
subsequent LOA.

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. Some of the reporting 
requirements are still in development and the final rulemaking may 
contain additional details not contained here. Additionally, proposed 
reporting requirements may be modified, removed, or added based on 
information or comments received during the public comment period. 
Reports from individual monitoring events, results of analyses, 
publications, and periodic progress reports for specific monitoring 
projects would be posted to the Navy's Marine Species Monitoring web 
portal: http://www.navymarinespeciesmonitoring.us. Currently, there are 
several different reporting requirements pursuant to these proposed 
regulations:

General Notification of Injured or Dead Marine Mammals

    Navy personnel would ensure that NMFS (the appropriate Regional 
Stranding Coordinator) is notified immediately (or as soon as clearance 
procedures allow) if an injured or dead marine mammal is found during 
or shortly after, and in the vicinity of, any Navy training exercise 
utilizing MFAS, HFAS, or underwater explosive detonations. The Navy 
would provide NMFS with species identification or a 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 photographs or video (if available). The Navy 
shall consult the Stranding Response Plan to obtain more specific 
reporting requirements for specific circumstances.

Vessel Strike

    NMFS has developed the following language to address monitoring and 
reporting measures specific to vessel strike. Most of this language 
comes directly from the Stranding Response Plan for other Navy training 
and testing rulemakings. This section has also been included in the 
regulatory text at the end of this proposed rule. Vessel strike during 
Navy training activities in the Study Area is not anticipated; however, 
in the event that a Navy vessel strikes a whale, the Navy shall do the 
following:
    Immediately report to NMFS (pursuant to the established 
Communication Protocol) the:
     Species identification (if known);
     Location (latitude/longitude) of the animal (or location 
of the strike if the animal has disappeared);
     Whether the animal is alive or dead (or unknown); and
     The time of the strike.
    As soon as feasible, the Navy shall report to or provide to NMFS, 
the:
     Size, length, and description (critical if species is not 
known) of animal;
     An estimate of the injury status (e.g., dead, injured but 
alive, injured and moving, blood or tissue observed in the water, 
status unknown, disappeared, etc.);
     Description of the behavior of the whale during event, 
immediately after the strike, and following the strike (until the 
report is made or the animal is no longer sighted);
     Vessel class/type and operational status;
     Vessel length;
     Vessel speed and heading; and
     To the best extent possible, obtain a photo or video of 
the struck animal, if the animal is still in view.
    Within 2 weeks of the strike, provide NMFS:
     A detailed description of the specific actions of the 
vessel in the 30-minute timeframe immediately preceding the strike, 
during the event, and immediately after the strike (e.g., the speed and 
changes in speed, the direction and changes in direction, other 
maneuvers, sonar use, etc., if not classified);
     A narrative description of marine mammal sightings during 
the event and immediately after, and any information as to sightings 
prior to the strike, if available; and use established Navy shipboard 
procedures to make a camera available to attempt to capture photographs 
following a ship strike.
    NMFS and the Navy will coordinate to determine the services the 
Navy may provide to assist NMFS with the investigation of the strike. 
The response and support activities to be provided by the Navy are 
dependent on resource availability, must be consistent with military 
security, and must be logistically feasible without compromising Navy 
personnel safety. Assistance requested and provided may vary based on 
distance of strike from shore, the nature of the vessel that hit the 
whale, available nearby Navy resources, operational and installation 
commitments, or other factors.

Annual GOA TMAA Monitoring Report

    The Navy shall submit an annual report of the GOA TMAA monitoring 
describing the implementation and results from the previous calendar 
year. Data collection methods will be standardized across range 
complexes and study areas to allow for comparison in different 
geographic locations. Although additional information will be gathered, 
Navy Lookouts collecting marine mammal data pursuant to the GOA TMAA 
monitoring plan shall, at a minimum, provide the same marine mammal 
observation data required in Sec.  218.155. The report shall be 
submitted either 90 days after the calendar year, or 90 days after the 
conclusion of the monitoring year to be determined by the Adaptive 
Management process. The GOA TMAA Monitoring Report may be provided to 
NMFS within a larger report that includes the required Monitoring Plan 
reports from multiple range complexes and study areas (the multi-Range 
Complex Annual Monitoring Report). Such a report would describe 
progress of knowledge made with respect to monitoring plan study 
questions across all Navy ranges associated with the Integrated 
Comprehensive Monitoring Program. Similar study questions shall be 
treated together so that progress on each topic shall be summarized 
across all Navy ranges. The report need not include analyses and 
content that does not provide direct assessment of cumulative progress 
on the monitoring plan study questions.

Annual GOA TMAA Exercise Report

    Each year, the Navy shall submit a preliminary report detailing the 
status of authorized sound sources within 21 days after the anniversary 
of the date of issuance of the LOA. Each year, the Navy shall submit a 
detailed report within 3 months after the anniversary of the date of 
issuance of the LOA. The annual report shall contain information on 
Major Training Exercises (MTEs), Sinking Exercise (SINKEX) events, and 
a summary of all sound sources used (total hours or quantity [per the 
LOA] of each bin of sonar or other non-impulsive source; total annual 
number of each type of explosive exercises; and total annual expended/
detonated rounds [missiles, bombs, sonobuoys, etc.] for each explosive 
bin). The analysis in the detailed report will be

[[Page 9992]]

based on the accumulation of data from the current year's report and 
data collected from previous the report. Information included in the 
classified annual reports may be used to inform future adaptive 
management of activities within the GOA TMAA.

Sonar Exercise Notification

    The Navy shall submit to NMFS (specific contact information to be 
provided in LOA) an electronic report within fifteen calendar days 
after the completion of any major training exercise indicating: 
Location of the exercise; beginning and end dates of the exercise; and 
type of exercise.

5-Year Close-Out Exercise Report

    This report will be included as part of the 2021 annual exercise 
report. This report will provide the annual totals for each sound 
source bin with a comparison to the annual allowance and the 5-year 
total for each sound source bin with a comparison to the 5-year 
allowance. Additionally, if there were any changes to the sound source 
allowance, this report will include a discussion of why the change was 
made and include the analysis to support how the change did or did not 
result in a change in the SEIS and final rule determinations. The 
report will be submitted 3 months after the expiration of the rule. 
NMFS will submit comments on the draft close-out report, if any, within 
3 months of receipt. The report will be considered final after the Navy 
has addressed NMFS' comments, or 3 months after the submittal of the 
draft if NMFS does not provide comments.

Estimated Take of Marine Mammals

    In the Potential Effects section, NMFS' analysis identified the 
lethal responses, physical trauma, sensory impairment (PTS, TTS, and 
acoustic masking), physiological responses (particular stress 
responses), and behavioral responses that could potentially result from 
exposure to MFAS/HFAS or underwater explosive detonations. In this 
section, the potential effects to marine mammals from MFAS/HFAS and 
underwater detonation of explosives will be related to the MMPA 
regulatory definitions of Level A and Level B harassment and we will 
attempt to quantify the effects that might occur from the proposed 
training activities in the Study Area.
    As mentioned previously, behavioral responses are context-
dependent, complex, and influenced to varying degrees by a number of 
factors other than just received level. 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. At greater 
distances, the nature of vessel movements could also potentially not 
have any effect on the animal's response to the sound. 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, or other factors. So, while sound sources and the received 
levels are the primary focus of the analysis and those that are laid 
out quantitatively in the regulatory text, it is with the understanding 
that other factors related to the training sometimes contribute to the 
behavioral responses of marine mammals, although they cannot be 
quantified.

Definition of Harassment

    As mentioned previously, with respect to military readiness 
activities, section 3(18)(B) of the MMPA defines ``harassment'' as: 
``(i) any act that injures or has the significant potential to injure a 
marine mammal or marine mammal stock in the wild [Level A Harassment]; 
or (ii) any act that disturbs or is likely to disturb a marine mammal 
or marine mammal stock in the wild by causing disruption of natural 
behavioral patterns, including, but not limited to, migration, 
surfacing, nursing, breeding, feeding, or sheltering, to a point where 
such behavioral patterns are abandoned or significantly altered [Level 
B Harassment].'' It is important to note that, as Level B harassment is 
interpreted here and quantified by the behavioral thresholds described 
below, the fact that a single behavioral pattern (of unspecified 
duration) is abandoned or significantly altered and classified as a 
Level B take does not mean, necessarily, that the fitness of the 
harassed individual is affected either at all or significantly, or 
that, for example, a preferred habitat area is abandoned. Further 
analysis of context and duration of likely exposures and effects is 
necessary to determine the impacts of the estimated effects on 
individuals and how those may translate to population level impacts, 
and is included in the Analysis and Negligible Impact Determination.

Level B Harassment

    Of the potential effects that were described earlier in this 
proposed rule, the following are the types of effects that fall into 
the Level B harassment category:
    Behavioral Harassment--Behavioral disturbance that rises to the 
level described in the definition above, when resulting from exposures 
to non-impulsive or impulsive sound, is considered Level B harassment. 
Some of the lower level physiological stress responses discussed 
earlier would also likely co-occur with the predicted harassments, 
although these responses are more difficult to detect and fewer data 
exist relating these responses to specific received levels of sound. 
When Level B harassment is predicted based on estimated behavioral 
responses, those takes may have a stress-related physiological 
component as well. Except for some vocalization changes that may be 
compensating for auditory masking, all behavioral reactions are assumed 
to occur due to a preceding stress or cueing response; however, stress 
responses cannot be predicted directly due to a lack of scientific 
data. Responses can overlap; for example, an increased respiration rate 
is likely to be coupled to a flight response or other avoidance 
behavior. Factors to consider when trying to predict a stress response 
include the mammal's life history stage and whether they are na[iuml]ve 
or experienced with the sound. Prior experience with a stressor may be 
of particular importance as repeated experience with a stressor may 
dull the stress response via acclimation (St. Aubin and Dierauf, 2001; 
Bejder et al., 2009).
    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 patters, temporary avoidance of an 
area, or temporary disruption of feeding, migrating, or reproductive 
behaviors. The estimates calculated by the Navy using the acoustic 
thresholds 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. We therefore 
consider the available scientific evidence to determine the likely 
nature of the modeled behavioral responses and the potential fitness 
consequences for affected individuals.
    Acoustic Masking and Communication Impairment--Acoustic masking and 
communication impairment are considered Level B harassment as they can 
disrupt natural behavioral patterns by interrupting or limiting the 
marine mammal's receipt or transmittal of important information or

[[Page 9993]]

environmental cues. As discussed in the Analysis and Negligible Impact 
Determination later in this proposed rule, masking effects from MFAS/
HFAS are expected to be minimal. If masking or communication impairment 
were to occur briefly, it would be in the frequency range of MFAS, 
which overlaps with some marine mammal vocalizations; however, it would 
likely not mask the entirety of any particular vocalization, 
communication series, or other critical auditory cue, because the 
signal length, frequency, and duty cycle of the MFAS/HFAS signal does 
not perfectly mimic the characteristics of any marine mammal's 
vocalizations. The other sources used in Navy training, many of either 
higher frequencies (meaning that the sounds generated attenuate even 
closer to the source) or lower amounts of operation, are similarly not 
expected to result in masking or communication impairment.
    Temporary Threshold Shift (TTS)--As discussed previously, TTS can 
affect how an animal behaves in response to the environment, including 
conspecifics, predators, and prey. The following physiological 
mechanisms are thought to play a role in inducing auditory fatigue: 
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. 
Ward (1997) suggested that when these effects result in TTS rather than 
PTS, they are within the normal bounds of physiological variability and 
tolerance and do not represent a physical injury. Additionally, 
Southall et al. (2007) indicate that although PTS is a tissue injury, 
TTS is not because the reduced hearing sensitivity following exposure 
to intense sound results primarily from fatigue, not loss, of cochlear 
hair cells and supporting structures and is reversible. Accordingly, 
NMFS classifies TTS (when resulting from exposure to sonar and other 
active acoustic sources and explosives and other impulsive sources) as 
Level B harassment, not Level A harassment (injury).
    The sound characteristics that correlate with specific stress 
responses in marine mammals are poorly understood. Therefore, in 
practice, a stress response is assumed if a physiological reaction such 
as a hearing loss (threshold shift--i.e., TTS or PTS) or trauma is 
predicted (or if a behavioral response is predicted, as discussed in 
the Level B Harassment section).
    Only non-TTS behavioral reactions and TTS are anticipated with the 
GOA TMAA training activities, and these Level B behavioral harassment 
takes are enumerated in Tables 12 and 13 and in the Negligible Impact 
Determination later in this proposed rule.

Level A Harassment

    Of the potential effects that were described earlier, following are 
the types of effects that can fall into the Level A harassment category 
(unless they further rise to the level of serious injury or mortality):
    Permanent Threshold Shift (PTS)--PTS (resulting either from 
exposure to MFAS/HFAS or explosive detonations) is irreversible and 
considered an injury. PTS results from exposure to intense sounds that 
cause a permanent loss of inner or outer cochlear hair cells or exceed 
the elastic limits of certain tissues and membranes in the middle and 
inner ears and result in changes in the chemical composition of the 
inner ear fluids. As mentioned above for TTS, a stress response is 
assumed if a physiological reaction such as a hearing loss (PTS) or 
trauma is predicted.
    As discussed in the Negligible Impact Determination later in this 
proposed rule, only a small number (5) of Level A takes resulting from 
mild levels of PTS are predicted, and no serious injury or mortality 
takes are predicted, with the Navy's training activities in the GOA 
TMAA.
    Tissue Damage due to Acoustically Mediated Bubble Growth--A few 
theories suggest ways in which gas bubbles become enlarged through 
exposure to intense sounds (MFAS/HFAS) to the point where tissue damage 
results. In rectified diffusion, exposure to a sound field would cause 
bubbles to increase in size which could cause tissue damage that would 
be considered injurious. A short duration of sonar pings (such as that 
which an animal exposed to MFAS would be most likely to encounter) 
would not likely be long enough to drive bubble growth to any 
substantial size. Alternately, bubbles could be destabilized by high-
level sound exposures such that bubble growth then occurs through 
static diffusion of gas out of the tissues. The degree of 
supersaturation and exposure levels observed to cause microbubble 
destabilization are unlikely to occur, either alone or in concert 
because of how close an animal would need to be to the sound source to 
be exposed to high enough levels, especially considering the likely 
avoidance of the sound source and the required mitigation. For the 
reasons above, Level A harassment in the form of tissue damage from 
acoustically mediated bubble growth is not predicted for training 
activities in the GOA TMAA.
    Tissue Damage due to Behaviorally Mediated Bubble Growth--Several 
authors suggest mechanisms in which marine mammals could behaviorally 
respond to exposure to MFAS/HFAS by altering their dive patterns 
(unusually rapid ascent, unusually long series of surface dives, etc.) 
in a manner that might result in unusual bubble formation or growth 
ultimately resulting in tissue damage. In this scenario, the rate of 
ascent would need to be sufficiently rapid to compromise behavioral or 
physiological protections against nitrogen bubble formation.
    There is considerable disagreement among scientists as to the 
likelihood of this phenomenon (Piantadosi and Thalmann, 2004; Evans and 
Miller, 2003). Although it has been argued that traumas from recent 
beaked whale strandings are consistent with gas emboli and bubble-
induced tissue separations (Jepson et al., 2003; Fernandez et al., 
2005; Fern[aacute]ndez et al., 2012), nitrogen bubble formation as the 
cause of the traumas has not been verified. If tissue damage does occur 
by this phenomenon, it would be considered an injury. Recent modeling 
by Kvadsheim et al. (2012) determined that while behavioral and 
physiological responses to sonar have the potential to result in bubble 
formation, the actual observed behavioral responses of cetaceans to 
sonar did not imply any significantly increased risk over what may 
otherwise occur normally in individual marine mammals. Level A 
harassment in the form of tissue damage from behaviorally mediated 
bubble growth is not anticipated for training activities in the GOA 
TMAA.
    Physical Disruption of Tissues Resulting from Explosive Shock 
Wave--Physical damage of tissues resulting from a shock wave (from an 
explosive detonation) is classified as an injury. Blast effects are 
greatest at the gas-liquid interface (Landsberg, 2000) and gas-
containing organs, particularly the lungs and gastrointestinal tract, 
are especially susceptible (Goertner, 1982; Hill 1978; Yelverton et 
al., 1973). Nasal sacs, larynx, pharynx, trachea, and lungs may be 
damaged by compression/expansion caused by the oscillations of the 
blast gas bubble (Reidenberg and Laitman, 2003). Severe damage (from 
the shock wave) to the ears can include tympanic membrane rupture, 
fracture of the ossicles, damage to the cochlea, hemorrhage, and 
cerebrospinal fluid leakage into the middle ear. Explosions in the 
ocean or near the water surface can introduce loud, impulsive,

[[Page 9994]]

broadband sounds into the marine environment. These sounds are likely 
within the audible range of most marine mammals, but the duration of 
individual sounds is very short. The direct sound from explosions used 
during training activities last less than a second, and most events 
involve the use of only one or a few explosions. Furthermore, events 
are dispersed in time and throughout the GOA TMAA Study Area. These 
factors reduce the likelihood of these sources causing substantial 
physical disruption of tissues in marine mammals, especially when the 
avoidance and mitigation factors are taken into consideration. 
Consequently, no Level A harassment from explosive shock waves is 
anticipated from training activities in the GOA TMAA.
    Vessel or Ordnance Strike--Vessel strike or ordnance strike 
associated with the specified activities would be considered Level A 
harassment, serious injury, or mortality. There are no records of any 
Navy vessel strikes to marine mammals during training activities in the 
GOA TMMA Study Area. There have been Navy strikes of large whales in 
areas outside the Study Area, such as Hawaii and Southern California. 
However, these areas differ significantly from the Study Area given 
that both Hawaii and Southern California have a much higher number of 
Navy vessel activities and much higher densities of large whales. The 
Navy's proposed actions would not result in any appreciable changes in 
locations or frequency of vessel activity, and there have been no whale 
strikes during any previous training activities in the Study Area. The 
manner in which the Navy has trained would remain consistent with the 
range of variability observed over the last decade so the Navy does not 
anticipate vessel strikes would occur within the Study Area during 
training events. As such, vessel or ordnance strike is not anticipated 
with the Navy activities in the Study Area and Level A harassment, 
serious injury, or mortality are not expected.

Take Thresholds

    For the purposes of an MMPA authorization, three types of take are 
identified: Level B harassment; Level A harassment; and mortality (or 
serious injury leading to mortality). The categories of marine mammal 
responses (physiological and behavioral) that fall into the two 
harassment categories were described in the previous section.
    Because the physiological and behavioral responses of the majority 
of the marine mammals exposed to non-impulse and impulse sounds cannot 
be easily detected or measured, and because NMFS must authorize take 
prior to the impacts to marine mammals, a method is needed to estimate 
the number of individuals that will be taken, pursuant to the MMPA, 
based on the proposed action. To this end, NMFS developed acoustic 
thresholds that estimate at what received level (when exposed to non-
impulse or impulse sounds) Level B harassment and Level A harassment of 
marine mammals would occur. The acoustic thresholds for non-impulse and 
impulse sounds are discussed below.
    Level B Harassment Threshold (TTS)--Behavioral disturbance, 
acoustic masking, and TTS are all considered Level B harassment. Marine 
mammals would usually be behaviorally disturbed at lower received 
levels than those at which they would likely sustain TTS, so the levels 
at which behavioral disturbance are likely to occur is considered the 
onset of Level B harassment. The behavioral responses of marine mammals 
to sound are variable, context specific, and, therefore, difficult to 
quantify (see Risk Function section, below).
    TTS is a physiological effect that has been studied and quantified 
in laboratory conditions. Because data exist to support an estimate of 
the received levels at which marine mammals will incur TTS, NMFS uses 
an acoustic criteria to estimate the number of marine mammals that 
might sustain TTS. TTS is a subset of Level B harassment (along with 
sub-TTS behavioral harassment) and the Navy is not specifically 
required to estimate those numbers; however, the more specifically the 
affected marine mammal responses can be estimated, the better the 
analysis.
    Level A Harassment Threshold (PTS)--For acoustic effects, because 
the tissues of the ear appear to be the most susceptible to the 
physiological effects of sound, and because threshold shifts tend to 
occur at lower exposures than other more serious auditory effects, NMFS 
has determined that PTS is the best indicator for the smallest degree 
of injury that can be measured. Therefore, the acoustic exposure 
associated with onset-PTS is used to define the lower limit of Level A 
harassment.
    PTS data do not currently exist for marine mammals and are unlikely 
to be obtained due to ethical concerns. However, PTS levels for these 
animals may be estimated using TTS data from marine mammals and 
relationships between TTS and PTS that have been determined through 
study of terrestrial mammals.
    We note here that behaviorally mediated injuries (such as those 
that have been hypothesized as the cause of some beaked whale 
strandings) could potentially occur in response to received levels 
lower than those believed to directly result in tissue damage. As 
mentioned previously, data to support a quantitative estimate of these 
potential effects (for which the exact mechanism is not known and in 
which factors other than received level may play a significant role) do 
not exist. However, based on the number of years (more than 60) and 
number of hours of MFAS per year that the U.S. (and other countries) 
has operated compared to the reported (and verified) cases of 
associated marine mammal strandings, NMFS believes that the probability 
of these types of injuries is very low. Tables 9 and 10 provide a 
summary of non-impulsive and impulsive thresholds to TTS and PTS for 
marine mammals. A detailed explanation of how these thresholds were 
derived is provided in the Criteria and Thresholds Technical Report 
(Finneran and Jenkins, 2012) and summarized in Chapter 6 of the LOA 
application (http://www.nmfs.noaa.gov/pr/permits/incidental/military.htm).

                           Table 9--Onset TTS and PTS Thresholds for Non-Impulse Sound
----------------------------------------------------------------------------------------------------------------
                Group                          Species                 Onset TTS                Onset PTS
----------------------------------------------------------------------------------------------------------------
Low-Frequency Cetaceans..............  All mysticetes.........  178 dB re 1[micro]Pa2-   198 dB re 1[micro]Pa2-
                                                                 sec(LFII).               sec(LFII).
Mid-Frequency Cetaceans..............  Most delphinids, beaked  178 dB re 1[micro]Pa2-   198 dB re 1[micro]Pa2-
                                        whales, medium and       sec(MFII).               sec(MFII).
                                        large toothed whales.
High-Frequency Cetaceans.............  Porpoises, Kogia spp...  152 dB re 1[micro]Pa2-   172 dB re 1[micro]Pa2-
                                                                 sec(HFII).               secSEL (HFII).
Phocidae In-water....................  Harbor, Hawaiian monk,   183 dB re 1[micro]Pa2-   197 dB re 1[micro]Pa2-
                                        elephant seals.          sec(PWI).                sec(PWI).

[[Page 9995]]

 
Otariidae & Obodenidae In-water......  Sea lions and fur seals  206 dB re 1[micro]Pa2-   220 dB re 1[micro]Pa2-
                                                                 sec(OWI).                sec(OWI).
Mustelidae In-water..................  Sea otters.............
----------------------------------------------------------------------------------------------------------------
LFII, MFII, HFII: New compound Type II weighting functions; PWI, OWI: Original Type I (Southall et al., 2007)
  for pinniped and mustelid in water.

  [GRAPHIC] [TIFF OMITTED] TP26FE16.000
  
Level B Harassment Risk Function (Behavioral Harassment)

    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 patters, temporary avoidance of an 
area, or temporary disruption of feeding, migrating, or reproductive 
behaviors. The estimates

[[Page 9996]]

calculated by the Navy using the acoustic thresholds 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. We therefore consider the available 
scientific evidence to determine the likely nature of the modeled 
behavioral responses and the potential fitness consequences for 
affected individuals.
    Behavioral Response Criteria for Non-Impulsive Sound from Sonar and 
other Active Sources--In 2006, NMFS issued the first MMPA authorization 
to allow the take of marine mammals incidental to MFAS (to the Navy for 
RIMPAC). For that authorization, NMFS used 173 dB SEL as the criterion 
for the onset of behavioral harassment (Level B harassment). This type 
of single number criterion is referred to as a step function, in which 
(in this example) all animals estimated to be exposed to received 
levels above 173 db SEL would be predicted to be taken by Level B 
Harassment and all animals exposed to less than 173 dB SEL would not be 
taken by Level B harassment. As mentioned previously, marine mammal 
behavioral responses to sound are highly variable and context specific 
(affected by differences in acoustic conditions; differences between 
species and populations; differences in gender, age, reproductive 
status, or social behavior; or the prior experience of the 
individuals), which means that there is support for alternate 
approaches for estimating behavioral harassment.
    Unlike step functions, acoustic risk continuum functions (which are 
also called ``exposure-response functions'' or ``dose-response 
functions'' in other risk assessment contexts) allow for probability of 
a response that NMFS would classify as harassment to occur over a range 
of possible received levels (instead of one number) and assume that the 
probability of a response depends first on the ``dose'' (in this case, 
the received level of sound) and that the probability of a response 
increases as the ``dose'' increases. In January 2009, NMFS issued three 
final rules governing the incidental take of marine mammals (within 
Navy's Hawaii Range, Southern California Training and Testing Range, 
and Atlantic Fleet Active Sonar Training complexes) that used a risk 
continuum to estimate the percent of marine mammals exposed to various 
levels of MFAS that would respond in a manner NMFS considers 
harassment.
    The Navy and NMFS have previously used acoustic risk functions to 
estimate the probable responses of marine mammals to acoustic exposures 
for other training and research programs. Examples of previous 
application include the Navy FEISs on the Surveillance Towed Array 
Sensor System Low Frequency Active (SURTASS LFA) sonar (U.S. Department 
of the Navy, 2001c); the North Pacific Acoustic Laboratory experiments 
conducted off the Island of Kauai (Office of Naval Research, 2001), and 
the Supplemental EIS for SURTASS LFA sonar (U.S. Department of the 
Navy, 2007d). As discussed earlier, factors other than received level 
(such as distance from or bearing to the sound source, context of 
animal at time of exposure) can affect the way that marine mammals 
respond; however, data to support a quantitative analysis of those (and 
other factors) do not currently exist. It is also worth specifically 
noting that while context is very important in marine mammal response, 
given otherwise equivalent context, the severity of a marine mammal 
behavioral response is also expected to increase with received level 
(Houser and Moore, 2014). NMFS will continue to modify these criteria 
as new data become available and can be appropriately and effectively 
incorporated.
    The particular acoustic risk functions developed by NMFS and the 
Navy (see Figures 1 and 2 of the LOA application) estimate the 
probability of behavioral responses to MFAS/HFAS (interpreted as the 
percentage of the exposed population) that NMFS would classify as 
harassment for the purposes of the MMPA given exposure to specific 
received levels of MFAS/HFAS. The mathematical function (below) 
underlying this curve is a cumulative probability distribution adapted 
from a solution in Feller (1968) and was also used in predicting risk 
for the Navy's SURTASS LFA MMPA authorization as well.
[GRAPHIC] [TIFF OMITTED] TP26FE16.001

Where:
R = Risk (0--1.0)
L = Received level (dB re: 1 [micro]Pa)
B = Basement received level = 120 dB re: 1 [micro]Pa
K = Received level increment above B where 50-percent risk = 45 dB 
re: 1 [micro]Pa
A = Risk transition sharpness parameter = 10 (odontocetes and 
pinnipeds) or 8 (mysticetes)

    Detailed information on the above equation and its parameters is 
available in the LOA application and previous Navy documents listed 
above.
    The harbor porpoise and beaked whales have unique criteria based on 
specific data that show these animals to be especially sensitive to 
sound. Harbor porpoise and beaked whale non-impulsive behavioral 
criteria are used unweighted--without weighting the received level 
before comparing it to the threshold (see Finneran and Jenkins, 2012).
    It has been speculated for some time that beaked whales might have 
unusual sensitivities to sonar sound due to their likelihood of 
stranding in conjunction with mid-frequency sonar use, even in areas 
where other species were more abundant (D'Amico et al., 2009), but 
there were not sufficient data to support a separate treatment for 
beaked whales until recently. With the recent publication of results 
from Blainville's beaked whale monitoring and experimental exposure 
studies on the instrumented AUTEC range in the Bahamas (McCarthy et al. 
2011; Tyack et al. 2011), there are now statistically strong data 
suggesting that beaked whales tend to avoid actual naval mid-frequency 
sonar in real anti-submarine training scenarios as well as playbacks of 
killer whale vocalizations, and other anthropogenic sounds. Tyack et 
al. (2011) report that, in reaction to sonar playbacks, most beaked 
whales stopped echolocating, made long slow ascent, and moved away from 
the sound. During an exercise using mid-frequency sonar, beaked whales 
avoided the sonar acoustic footprint at a distance where the received 
level was ``around 140 dB'' (SPL) and once the exercise ended, beaked 
whales re-inhabited the center of exercise area within 2-3 days (Tyack 
et al., 2011). The Navy has therefore adopted an unweighted 140 dB re 1 
[micro]Pa SPL threshold for significant behavioral effects for all 
beaked whales (family: Ziphiidae).
    Since the development of the criterion, analysis of the data the 
2010 and 2011 field seasons of the southern California Behavioral 
Responses Study have been published. The study, DeRuiter et al. 
(2013b), provides similar evidence of Cuvier's beaked whale 
sensitivities to sound based on two controlled exposures. Two whales, 
one in each season, were tagged and exposed to simulated mid-frequency 
active sonar at distances of 3.4-9.5 km. The 2011 whale was also 
incidentally exposed to mid-frequency active sonar from a distant naval 
exercise (approximately 118 km away). Received levels from the mid-
frequency active sonar signals during the controlled and incidental 
exposures were calculated as

[[Page 9997]]

84-144 and 78-106 dB re 1 [micro]Pa rms, respectively. Both whales 
showed responses to the controlled exposures, ranging from initial 
orientation changes to avoidance responses characterized by energetic 
fluking and swimming away from the source. However, the authors did not 
detect similar responses to incidental exposure to distant naval sonar 
exercises at comparable received levels, indicating that context of the 
exposures (e.g., source proximity, controlled source ramp-up) may have 
been a significant factor. Because the sample size was limited 
(controlled exposures during a single dive in both 2010 and 2011) and 
baseline behavioral data was obtained from different stocks and 
geographic areas (i.e., Hawaii and Mediterranean Sea), and the 
responses exhibited to controlled exposures were not exhibited by an 
animal exposed to some of the same received levels of real sonar 
exercises, the Navy relied on the studies at the AUTEC that analyzed 
beaked whale responses to actual naval exercises using mid-frequency 
active sonar to evaluate potential behavioral responses by beaked 
whales to proposed training and testing activities using sonar and 
other active acoustic sources.
    The information currently available regarding harbor porpoises 
suggests a very low threshold level of response for both captive and 
wild animals. Threshold levels at which both captive (Kastelein et al., 
2000; Kastelein et al., 2005; Kastelein et al., 2006; Kastelein et al., 
2008) and wild harbor porpoises (Johnston, 2002) responded to sound 
(e.g., acoustic harassment devices, acoustic deterrent devices, or 
other non-impulsive sound sources) are very low (e.g., approximately 
120 dB re 1 [mu]Pa). Therefore, a SPL of 120 dB re 1 [mu]Pa is used in 
this analysis as a threshold for predicting behavioral responses in 
harbor porpoises instead of the risk functions used for other species 
(i.e., we assume for the purpose of estimating take that all harbor 
porpoises exposed to 120 dB or higher MFAS/HFAS will be taken by Level 
B behavioral harassment).
    Behavioral Response Criteria for Impulsive Sound from Explosions -- 
If more than one explosive event occurs within any given 24-hour period 
within a training or testing event, behavioral criteria are applied to 
predict the number of animals that may be taken by Level B harassment. 
For multiple explosive events the behavioral threshold used in this 
analysis is 5 dB less than the TTS onset threshold (in sound exposure 
level). This value is derived from observed onsets of behavioral 
response by test subjects (bottlenose dolphins) during non-impulse TTS 
testing (Schlundt et al., 2000). Some multiple explosive events, such 
as certain naval gunnery exercises, may be treated as a single 
impulsive event because a few explosions occur closely spaced within a 
very short period of time (a few seconds). For single impulses at 
received sound levels below hearing loss thresholds, the most likely 
behavioral response is a brief alerting or orienting response. Since no 
further sounds follow the initial brief impulses, Level B take in the 
form of behavioral harassment beyond that associated with potential TTS 
would not be expected to occur. This reasoning was applied to previous 
shock trials (63 FR 230; 66 FR 87; 73 FR 143) and is extended to these 
Phase 2 criteria. Behavioral thresholds for impulsive sources are 
summarized in Table 11 and further detailed in the LOA application.
    Since impulse events can be quite short, it may be possible to 
accumulate multiple received impulses at sound pressure levels 
considerably above the energy-based criterion and still not be 
considered a behavioral take. The Navy treats all individual received 
impulses as if they were one second long for the purposes of 
calculating cumulative sound exposure level for multiple impulse 
events. For example, five air gun impulses, each 0.1 second long, 
received at a Type II weighted sound pressure level of 167 dB SPL would 
equal a 164 dB sound exposure level, and would not be predicted as 
leading to a significant behavioral response (take) in MF or HF 
cetaceans. However, if the five 0.1 second pulses are treated as a 5 
second exposure, it would yield an adjusted SEL of approximately 169 
dB, exceeding the behavioral threshold of 167 dB SEL. For impulses 
associated with explosions that have durations of a few microseconds, 
this assumption greatly overestimates effects based on sound exposure 
level metrics such as TTS and PTS and behavioral responses. Appropriate 
weighting values will be applied to the received impulse in one-third 
octave bands and the energy summed to produce a total weighted sound 
exposure level value. For impulsive behavioral criteria, the Navy's 
weighting functions (detailed in Chapter 6 of the LOA application) are 
applied to the received sound level before being compared to the 
threshold.

           Table 11--Behavioral Thresholds for Impulsive Sound
------------------------------------------------------------------------
                                       Impulsive
                                      behavioral
          Hearing group            threshold for > 2       Onset TTS
                                    pulses/24 hours
------------------------------------------------------------------------
Low-Frequency Cetaceans.........  167 dB SEL (LFII).  172 dB SEL (MFII)
                                                       or 224 dB Peak
                                                       SPL.
Mid-Frequency Cetaceans.........  167 dB SEL (MFII).
High-Frequency Cetaceans........  141 dB SEL (HFII).  146 dB SEL (HFII)
                                                       or 195 dB Peak
                                                       SPL.
Phocid Seals (in water).........  172 dB SEL (PWI)..  177 dB SEL (PWI)
                                                       or 212 dB Peak
                                                       SPL.
Otariidae & Mustelidae (in        195 dB SEL (OWI)..  200 dB SEL (OWI)
 water).                                               or 212 dB Peak
                                                       SPL.
------------------------------------------------------------------------
Notes: (1) LFII, MFII, HFII are New compound Type II weighting
  functions; PWI, OWI = Original Type I (Southall et al., 2007) for
  pinniped and mustelid in water (see Finneran and Jenkins 2012). (2)
  SEL = re 1 [mu]Pa\2\-s; SPL = re 1 [mu]Pa, SEL = Sound Exposure Level,
  dB = decibel, SPL = Sound Pressure Level.

Marine Mammal Density Estimates

    A quantitative impact analysis requires an estimate of the number 
of animals that might be affected by anthropogenic activities. A key 
element of this estimation is knowledge of the abundance and 
concentration of the species in specific areas where those activities 
will occur. The most appropriate unit of metric for this type of 
analysis is animal density, or the number of animals present per unit 
area. Marine species density estimation requires a significant amount 
of effort to both collect and analyze data to produce a reasonable 
estimate. Unlike surveys for terrestrial wildlife, many marine species 
spend much of their time submerged, and are not easily observed. In 
order to collect enough sighting data to make reasonable density 
estimates, multiple observations are required, often in areas that are 
not easily accessible (e.g., far offshore). Ideally, marine species 
sighting data would be collected for the specific area and time period 
(e.g., season) of interest and density estimates derived accordingly. 
However, in many places, poor weather conditions and high sea states 
prohibit

[[Page 9998]]

the completion of comprehensive visual surveys.
    For most cetacean species, abundance is estimated using line-
transect surveys or mark-recapture studies (e.g., Barlow, 2010, Barlow 
and Forney, 2007, Calambokidis et al., 2008). The result provides one 
single density estimate value for each species across broad geographic 
areas, such as waters within the U.S. EEZ off California, Oregon, and 
Washington. This is the general approach applied in estimating cetacean 
abundance in the NMFS Stock Assessment Reports. Although the single 
value provides a good average estimate of abundance (total number of 
individuals) for a specified area, it does not provide information on 
the species distribution or concentrations within that area, and it 
does not estimate density for other timeframes or seasons that were not 
surveyed. More recently, habitat modeling has been used to estimate 
cetacean densities (Barlow et al., 2009; Becker et al., 2010, 2012a, b, 
c; Ferguson et al., 2006a; Forney et al., 2012; Redfern et al., 2006). 
These models estimate cetacean density as a continuous function of 
habitat variables (e.g., sea surface temperature, seafloor depth, etc.) 
and thus allow predictions of cetacean densities on finer spatial 
scales than traditional line-transect or mark-recapture analyses. 
Within the geographic area that was modeled, densities can be predicted 
wherever these habitat variables can be measured or estimated.
    Uncertainty in published density estimates is typically large 
because of the low number of sightings available for their derivation. 
Uncertainty is typically expressed by the coefficient of variation (CV) 
of the estimate, which is derived using standard statistical methods 
and describes the amount of variation with respect to the population 
mean. It is expressed as a fraction or sometimes a percentage and can 
range upward from zero, indicating no uncertainty, to high values. For 
example, a CV of 0.85 would indicate high uncertainty in the population 
estimate. When the CV exceeds 1.0, the estimate is very uncertain. The 
uncertainty associated with movements of animals into or out of an area 
(due to factors such as availability of prey or changing oceanographic 
conditions) is much larger than is indicated by the CV.
    The methods used to estimate pinniped at-sea densities are 
typically different than those used for cetaceans. This is discussed in 
more detail in the Navy Marine Species Density Database Technical 
Report (U.S. Department of the Navy, 2014). Pinniped abundance is 
generally estimated via shore counts of animals at known rookeries and 
haulout sites. Translating these numbers to in-water densities is 
difficult given the variability in foraging ranges, migration, and 
haulout behavior between species and within each species, and is driven 
by factors such as age class, sex class, seasonal variation, etc. 
Details of the density derivation for each species of pinniped in the 
Study Area are provided in the U.S. Department of the Navy (2014). In 
summary, the methods used to derive pinniped densities involved a 
series of species-specific data reviews to compile the most accurate 
and up-to-date information available. The total abundance divided by 
the area of the region was the resultant density estimate for each 
species in a given location.
    There is no single source of density data for every area, marine 
mammal species, and season because of the fiscal costs, resources, and 
effort involved to provide enough survey coverage to sufficiently 
estimate density. NMFS Southwest Fisheries Science Center conducts 
standard U.S. West Coast surveys every 5-6 years and cannot 
logistically support more frequent studies. The U.S. Navy has funded 
two previous marine mammal surveys in the GOA TMAA (Rone et al., 2009, 
2014) in the summer time-period when Navy training activities are most 
likely to occur. The density data used to quantitatively estimate 
impacts to marine mammals from Navy training in the GOA TMAA are based 
on the best available science and were agreed upon with NMFS as a 
cooperating agency for the SEIS/OEIS. As the federal regulator for the 
MMPA, the NMFS role included having staff biologists review and comment 
on the analysis and the SEIS/OEIS. The review also included 
coordination with NMFS regional scientists from the Southwest Fisheries 
Science Center and Alaska Fisheries Science Center on the latest 
emergent data presented in their Pacific Stock Assessment Reports.
    In May 2015, the Marine Mammal Commission also reviewed the Marine 
Species Density Database Technical Report (U.S. Department of the Navy, 
2014) and pointed out some textual errors that the Navy subsequently 
corrected, but otherwise did not identify any changes in the data used 
for acoustic effects modeling.
    A certain number of sightings are required to generate the quality 
of data necessary to produce either traditional line-transect density 
estimates or spatial habitat modeled density values. The at-sea 
identification of some species of specific MMPA designated stocks is 
not always possible from available field data, nor would additional 
data collection likely address the identification issue based on low 
animal occurrence (e.g., Western North Pacific gray whale), cryptic 
behaviors (e.g., beaked whales), and appearance similarities between 
stocks (e.g., Steller sea lions). In the absence of species-specific 
population survey data for these species, density estimates are derived 
from different methods and data sources, based on NMFS recommendations. 
The different methods for each of these species are described in 
Section 3.8.3.1.6.1 (Marine Species Density Data) of the DSEIS/OEIS and 
the Marine Species Density Database Technical Report (U.S. Department 
of the Navy, 2014). NMFS and Navy have determined that these 
alternative density estimates are sufficient for determining the 
impacts of Navy training on these marine mammals under all applicable 
statutes, and therefore are the best available science.
    Therefore, to characterize marine mammal density for areas of 
concern, including the GOA TMAA Study Area, the Navy compiled data from 
multiple sources. Each data source may use different methods to 
estimate density and uncertainty (e.g., variance) associated with the 
estimates.
    The Navy thus developed a protocol to select the best available 
data sources based on species, area, and time (season). The Navy then 
used this protocol to identify the best density data from available 
sources, including habitat-based density models, line-transect 
analyses, and peer-reviewed published studies. These data were 
incorporated into a Geographic Information System database that 
includes seasonal (summer/fall and winter/spring) density values for 
every marine mammal species present within the Study Area. Detailed 
information on the Navy's selection protocol, datasets, and specific 
density values are provided in the Navy Marine Species Density Database 
Technical Report (U.S. Department of the Navy, 2014).

Quantitative Modeling To Estimate Take for Impulsive and Non-Impulsive 
Sound

    The Navy performed a quantitative analysis to estimate the number 
of marine mammals that could be affected by acoustic sources or 
explosives used during Navy training activities. Inputs to the 
quantitative analysis include marine mammal density estimates; marine 
mammal depth occurrence distributions; oceanographic and environmental 
data; marine mammal hearing data; and criteria and thresholds for 
levels of potential effects. The quantitative analysis consists of

[[Page 9999]]

computer modeled estimates and a post-model analysis to determine the 
number of potential mortalities and harassments. The model calculates 
sound energy propagation from sonar, other active acoustic sources, and 
explosives during naval activities; the sound or impulse received by 
animat (virtual representation of an animal) dosimeters representing 
marine mammals distributed in the area around the modeled activity; and 
whether the sound or impulse received by a marine mammal exceeds the 
thresholds for effects. The model estimates are then further analyzed 
to consider animal avoidance and implementation of mitigation measures, 
resulting in final estimates of potential effects due to Navy training.
    Various computer models and mathematical equations can be used to 
predict how energy spreads from a sound source (e.g., sonar or 
underwater detonation) to a receiver (e.g., dolphin or sea turtle). 
Basic underwater sound models calculate the overlap of energy and 
marine life using assumptions that account for the many, variable, and 
often unknown factors that can influence the result. Assumptions in 
previous and current Navy models have intentionally erred on the side 
of overestimation when there are unknowns or when the addition of other 
variables was not likely to substantively change the final analysis. 
For example, because the ocean environment is extremely dynamic and 
information is often limited to a synthesis of data gathered over wide 
areas and requiring many years of research, known information tends to 
be an average of a seasonal or annual variation. El Ni[ntilde]o 
Southern Oscillation events of the ocean-atmosphere system are an 
example of dynamic change where unusually warm or cold ocean 
temperatures are likely to redistribute marine life and alter the 
propagation of underwater sound energy. Previous Navy modeling 
therefore made some assumptions indicative of a maximum theoretical 
propagation for sound energy (such as a perfectly reflective ocean 
surface and a flat seafloor).
    More complex computer models build upon basic modeling by factoring 
in additional variables in an effort to be more accurate by accounting 
for such things as variable bathymetry and an animal's likely presence 
at various depths.
    The Navy has developed new software tools, up to date marine mammal 
density data, and other oceanographic data for the quantification of 
estimated acoustic impacts to marine mammal impacts from Navy 
activities. This new approach is the resulting evolution of the basic 
model previously used by the Navy and reflects a more complex modeling 
approach as described below. The new model, NAEMO, is the standard 
model now used by the navy to estimate the potential acoustic effects 
of Navy training and testing activities on marine mammals. Although 
this more complex computer modeling approach accounts for various 
environmental factors affecting acoustic propagation, the current 
software tools do not consider the likelihood that a marine mammal 
would attempt to avoid repeated exposures to a sound or avoid an area 
of intense activity where a training or testing event may be focused. 
Additionally, the software tools do not consider the implementation of 
mitigation (e.g., stopping sonar transmissions when a marine mammal is 
within a certain distance of a ship or mitigation zone clearance prior 
to detonations). In both of these situations, naval activities are 
modeled as though an activity would occur regardless of proximity to 
marine mammals and without any horizontal movement by the animal away 
from the sound source or human activities. Therefore, the final step of 
the quantitative analysis of acoustic effects is to consider the 
implementation of mitigation and the possibility that marine mammals 
would avoid continued or repeated sound exposures. This final, post-
analysis step in the modeling process is meant to better quantify the 
predicted effects by accounting for likely animal avoidance behavior 
and implementation of standard Navy mitigations.
    The incorporation of mitigation factors for the reduction of 
predicted effects used a conservative approach (erring on the side of 
overestimating the number of effects) since reductions as a result of 
implemented mitigation were only applied to those events having a very 
high likelihood of detecting marine mammals.
    The steps of the quantitative analysis of acoustic effects, the 
values and assumptions that went into the Navy's model, and the 
resulting ranges to effects are detailed in Chapter 6 (Section 6.5) of 
the LOA application (http://www.nmfs.noaa.gov/pr/permits/incidental/). 
Details of the model's processes and the description and derivation of 
the inputs are presented in the Navy's Determination of Acoustic 
Effects technical Report (Marine Species Modeling Team, 2014). The 
post-model analysis, which considers the potential for avoidance and 
highly effective mitigation during the use of sonar and other active 
acoustic sources and explosives, is described in Section 6.5 of the LOA 
application. A detailed explanation of the post-model acoustic effect 
analysis quantification process is also provided in the technical 
report Post-Model Quantitative Analysis of Animal Avoidance Behavior 
and Mitigation Effectiveness for the Gulf of Alaska Training (U.S. 
Department of the Navy, 2014c; also available at: http://goaeis.com/Documents/SupplementalEISOEISDocumentsandReferences/SupportingTechnicalDocuments.aspx).

Take Request

    The GOA DSEIS/OEIS considered all training activities proposed to 
occur in the Study Area that have the potential to result in the MMPA 
defined take of marine mammals. The stressors associated with these 
activities included the following:
     Acoustic (sonar and other active non-impulse sources, 
explosives, swimmer defense airguns, weapons firing, launch and impact 
noise, vessel noise, aircraft noise);
     Energy (electromagnetic devices);
     Physical disturbance or strikes (vessels, in-water 
devices, military expended materials, seafloor devices);
     Entanglement (fiber optic cables, guidance wires, 
parachutes);
     Ingestion (munitions, military expended materials other 
than munitions); and
     Secondary stressors (sediments and water quality).
    The Navy determined, and NMFS agrees, that two stressors could 
potentially result in the incidental taking of marine mammals from 
training activities within the Study Area: (1) Non-impulsive stressors 
(sonar and other active acoustic sources) and (2) impulsive stressors 
(explosives). Non-impulsive and impulsive stressors have the potential 
to result in incidental takes of marine mammals by harassment, injury, 
or mortality.

Training Activities

    A detailed analysis of effects due to marine mammal exposures to 
impulsive and non-impulsive sources in the Study Area is presented in 
Chapter 6 of the LOA application. Based on the model and post-model 
analysis described in Chapter 6 of the LOA application, Table 12 
summarizes the Navy's final take request for training activities for a 
year (up to 2 exercises occurring over a 7-month period [April-
October]) and the summation over a 5-year period (up to 2 exercises 
occurring over a 7-month period [April-October] for a total of 10 
exercises).

[[Page 10000]]



              Table 12--Summary of Annual and 5-Year Take Requests for GOA TMAA Training Activities
----------------------------------------------------------------------------------------------------------------
                                                                               Training activities
                                                               -------------------------------------------------
            MMPA Category                       Source            Annual authorization     5-Year authorization
                                                                         sought                   sought
----------------------------------------------------------------------------------------------------------------
Mortality............................  Explosives.............  0......................  0.
Level A..............................  Sonar and other active   5 (Dall's porpoise only  25 (Dall's porpoise
                                        acoustic sources;        as shown in Table 13).   only as shown in Table
                                        explosives.                                       13).
Level B..............................  Sonar and other active   36,522 (Species          182,610 (Species
                                        acoustic sources;        specific data shown in   specific data shown in
                                        explosives.              Table 13).               Table 13).
----------------------------------------------------------------------------------------------------------------

Impulsive and Non-Impulsive Sources

    Table 13 provides details on the Navy's final take request for 
training activities by species from the acoustic effects modeling 
estimates. Derivations of the numbers presented in Table 13 are 
described in more detail within Chapter 6 of the LOA application. Level 
A effects are only predicted to occur for Dall's porpoises. There are 
no mortalities predicted for any of the proposed training activities.

 Table 13--Species-Specific Take Requests From Modeling Estimates of Impulsive and Non-Impulsive Source Effects
                                           for All Training Activities
----------------------------------------------------------------------------------------------------------------
                                                              Annual                          5-Year
            Species                   Stock      ---------------------------------------------------------------
                                                      Level B         Level A         Level B         Level A
----------------------------------------------------------------------------------------------------------------
North Pacific right whale.....  Eastern North                  7               0              35               0
                                 Pacific.
Humpback whale................  Central North                129               0             645               0
                                 Pacific.
                                Western North                 10               0              50               0
                                 Pacific.
Blue whale....................  Eastern North                 95               0             475               0
                                 Pacific.
                                Central North                  0               0               0               0
                                 Pacific.
Fin whale.....................  Northeast                  2,582               0          12,910               0
                                 Pacific.
Sei whale.....................  Eastern North                 13               0              65               0
                                 Pacific.
Minke whale...................  Alaska..........              87               0             435               0
Gray whale....................  Eastern North                  0               0               0               0
                                 Pacific.
                                Western North                  0               0               0               0
                                 Pacific.
Sperm whale...................  North Pacific...             197               0             985               0
Killer whale..................  Alaska Resident.             564               0           2,820               0
                                Eastern North                 53               0             265               0
                                 Pacific
                                 Offshore.
                                AT1 Transient...               1               0               5               0
                                GOA, Aleutian                144               0             720               0
                                 Island, and
                                 Bearing Sea
                                 Transient.
Pacific white-sided dolphin...  North Pacific...           1,963               0           9,815               0
Harbor porpoise...............  Gulf of Alaska..           5,484               0          27,420               0
                                Southeast Alaska           1,926               0           9,630               0
Dall's porpoise...............  Alaska..........          16,244               5          81,220              25
Cuvier's beaked whale.........  Alaska..........           2,544               0          12,720               0
Baird's beaked whale..........  Alaska..........             401               0           2,005               0
Stejneger's beaked whale......  Alaska..........           1,153               0           5,765               0
Steller sea lion..............  Eastern U.S.....             671               0           3,355               0
                                Western U.S.....             572               0           2,860               0
California sea lion...........  U.S.............               5               0              25               0
Northern fur seal.............  Eastern Pacific-           1,428               0           7,140               0
                                 Alaska.
Northern elephant seal........  California                   245               0           1,225               0
                                 Breeding.
Harbor seal...................  Aleutian Islands               0               0               0               0
                                Pribilof Islands               0               0               0               0
                                Bristol Bay.....               0               0               0               0
                                North Kodiak....               1               0               5               0
                                South Kodiak....               1               0               5               0
                                Prince William                 2               0              10               0
                                 Sound.
                                Cook Inlet/                    0               0               0               0
                                 Shelikof.
                                Glacier Bay/Icy                0               0               0               0
                                 Strait.
                                Lynn Canal/                    0               0               0               0
                                 Stephens.
Harbor seal...................  Sitka/Chatham...               0               0               0               0
                                Dixon/Cape                     0               0               0               0
                                 Decision.
                                Clarence Strait.               0               0               0               0
Ribbon seal...................  Alaska..........               0               0               0               0
                                                 ---------------------------------------------------------------
    Totals....................  ................          36,522               5         182,610              25
----------------------------------------------------------------------------------------------------------------

Marine Mammal Habitat

    The Navy's proposed training activities could potentially affect 
marine mammal habitat through the introduction of sound into the water 
column, impacts to the prey species of marine mammals, bottom 
disturbance, or changes in water quality. Each of these components was 
considered in the

[[Page 10001]]

GOA DSEIS/OEIS and was determined by the Navy to have no effect on 
marine mammal habitat. Based on the information below and the 
supporting information included in the GOA DSEIS/OEIS, NMFS has 
preliminarily determined that the proposed training activities would 
not have adverse or long-term impacts on marine mammal habitat.

Expected Effects on Habitat

    Unless the sound source or explosive detonation 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 the physical 
alteration of the habitat. Acoustic exposures are not expected to 
result in long-term physical alteration of the water column or bottom 
topography, as the occurrences are of limited duration and are 
intermittent in time. Surface vessels associated with the activities 
are present in limited duration and are intermittent as they move 
relatively rapidly through any given area. Most of the high-explosive 
military expended materials would detonate at or near the water 
surface. Only bottom-laid explosives are likely to affect bottom 
substrate; habitat used for underwater detonations and seafloor device 
placement would primarily be soft-bottom sediment. Once on the 
seafloor, military expended material would likely be colonized by 
benthic organisms because the materials would serve as anchor points in 
the shifting bottom substrates, similar to a reef. The surface area of 
bottom substrate affected would make up a very small percentage of the 
total training area available in the Study Area.

Effects on Marine Mammal Prey

    Invertebrates--Marine invertebrate distribution in the Study Area 
is influenced by habitat, ocean currents, and water quality factors 
such as temperature, salinity, and nutrient content (Levinton 2009). 
The distribution of invertebrates is also influenced by their distance 
from the equator (latitude); in general, the number of marine 
invertebrate species increases toward the equator (Macpherson 2002). 
The higher number of species (diversity) and abundance of marine 
invertebrates in coastal habitats, compared with the open ocean, is a 
result of more nutrient availability from terrestrial environments and 
the variety of habitats and substrates found in coastal waters 
(Levinton 2009).
    The GOA is one of the world's most productive ocean regions and the 
habitats associated with these cold and turbulent waters contain 
identifiable collections of macrohabitats that sustain a multitude of 
invertebrate species. Invertebrates in the GOA provide valuable links 
in the food chain and perform ecosystem functions such as nutrient 
processing. For humans, invertebrates contribute to economic, cultural, 
and recreational activities in the GOA.
    All marine invertebrate taxonomic groups are represented in the 
Study Area. Major invertebrate phyla and the general zones they inhabit 
in the Study Area are described in Chapter 3 of the 2011 GOA FEIS/OEIS.
    Very little is known about sound detection and use of sound by 
aquatic invertebrates (Budelmann 2010; Montgomery et al., 2006; Popper 
et al., 2001). Organisms may detect sound by sensing either the 
particle motion or pressure component of sound, or both. Aquatic 
invertebrates probably do not detect pressure since many are generally 
the same density as water and few, if any, have air cavities that would 
function like the fish swim bladder in responding to pressure 
(Budelmann, 2010; Popper et al., 2001). Many marine invertebrates, 
however, have ciliated ``hair'' cells that may be sensitive to water 
movements, such as those caused by currents or water particle motion 
very close to a sound source (Budelmann, 2010; Mackie and Singla, 
2003). These cilia may allow invertebrates to sense nearby prey or 
predators or help with local navigation. Marine invertebrates may 
produce and use sound in territorial behavior, to deter predators, to 
find a mate, and to pursue courtship (Popper et al., 2001).
    Both behavioral and auditory brainstem response studies suggest 
that crustaceans may sense sounds up to three kilohertz (kHz), but best 
sensitivity is likely below 200 Hz (Lovell et al., 2005; Lovell et al., 
2006; Goodall et al., 1990). Most cephalopods (e.g., octopus and squid) 
likely sense low-frequency sound below 1,000 Hz, with best 
sensitivities at lower frequencies (Budelmann, 2010; Mooney et al., 
2010; Packard et al., 1990). A few cephalopods may sense higher 
frequencies up to 1,500 Hz (Hu et al., 2009). Squid did not respond to 
toothed whale ultrasonic echolocation clicks at sound pressure levels 
ranging from 199 to 226 dB re 1 [mu]Pa peak-to-peak, likely because 
these clicks were outside of squid hearing range (Wilson et al., 2007). 
However, squid exhibited alarm responses when exposed to broadband 
sound from an approaching seismic airgun with received levels exceeding 
145 to 150 dB re 1 [mu]Pa root mean square (McCauley et al., 2000b).
    Little information is available on the potential impacts on marine 
invertebrates of exposure to sonar, explosions, and other sound-
producing activities. It is expected that most marine invertebrates 
would not sense mid- or high-frequency sounds, distant sounds, or 
aircraft noise transmitted through the air-water interface. Most marine 
invertebrates would not be close enough to intense sound sources, such 
as some sonars, to potentially experience impacts to sensory 
structures. Any marine invertebrate capable of sensing sound may alter 
its behavior if exposed to non-impulsive sound, although it is unknown 
if responses to non-impulsive sounds occur. Continuous noise, such as 
from vessels, may contribute to masking of relevant environmental 
sounds, such as reef noise. Because the distance over which most marine 
invertebrates are expected to detect any sounds is limited and vessels 
would be in transit, any sound exposures with the potential to cause 
masking or behavioral responses would be brief and long-term impacts 
are not expected. Although non-impulsive underwater sounds produced 
during training activities may briefly impact individuals, intermittent 
exposures to non-impulsive sounds are not expected to impact survival, 
growth, recruitment, or reproduction of widespread marine invertebrate 
populations.
    Detonations associated with the Navy's GOA TMAA activities would 
occur well offshore (the middle of the GOA TMAA is 140 nm offshore; 
except for a point near Cape Cleare on Montague Island [12 nm away], 
the nearest shoreline [Kenai Peninsula] is 24 nm north of the GOA TMAA 
northern boundary). As water depth increases away from shore, benthic 
invertebrates would be less likely to be impacted by detonations at or 
near the surface. In addition, detonations near the surface would 
release a portion of their explosive energy into the air, reducing the 
explosive impacts in the water. Some marine invertebrates may be 
sensitive to the low-frequency component of impulsive sound, and they 
may exhibit startle reactions or temporary changes in swim speed in 
response to an impulsive exposure. Because exposures are brief, limited 
in number, and spread over a large area, no long-term impacts due to 
startle reactions or short-term behavioral changes are expected. 
Although individual marine invertebrates may be injured or killed 
during an explosion or pile driving, no long-term impacts on

[[Page 10002]]

the survival, growth, recruitment, or reproduction of marine 
invertebrate populations are expected.
    Fish--Fish are not distributed uniformly throughout the Study Area, 
but are closely associated with a variety of habitats. Some species 
range across thousands of square miles while others have small home 
ranges and restricted distributions (Helfman et al., 2009). The 
movements of some open-ocean species may never overlap with coastal 
fishes that spend their lives within several hundred feet (a few 
hundred meters) of the shore. Even within a single fish species, the 
distribution and specific habitats in which individuals occur may be 
influenced by its developmental stage, size, sex, reproductive 
condition, and other factors.
    The distribution and abundance of fishes depends greatly on the 
physical and biological factors of the marine ecosystem, such as 
salinity, temperature, dissolved oxygen, population dynamics, predator 
and prey interaction oscillations, seasonal movements, reproduction and 
life cycles, and recruitment success (Helfman et al., 1997). A single 
factor is rarely responsible for the distribution of fish species; more 
often, a combination of factors is accountable. For example, open ocean 
species optimize their growth, reproduction, and survival by tracking 
gradients of temperature, oxygen, or salinity (Helfman et al., 1997). 
Another major component in understanding species distribution is the 
location of highly productive regions, such as frontal zones. These 
areas concentrate various prey species and their predators, such as 
tuna, and provide visual cues for the location of target species for 
commercial fisheries (NMFS, 2001).
    At least 383 species belonging to 84 families of marine and 
anadromous fishes have been reported from the predominant ecosystems 
found in the GOA TMAA. Detailed information on taxa presence, 
distribution, and characteristics are provided in Chapter 3 of the 2011 
GOA FEIS/OEIS.
    All fish have two sensory systems to detect sound in the water: The 
inner ear, which functions very much like the inner ear in other 
vertebrates, and the lateral line, which consists of a series of 
receptors along the fish's body (Popper, 2008). The inner ear generally 
detects relatively higher-frequency sounds, while the lateral line 
detects water motion at low frequencies (below a few hundred Hz) 
(Hastings and Popper, 2005a). Although hearing capability data only 
exist for fewer than 100 of the 32,000 fish species, current data 
suggest that most species of fish detect sounds from 50 to 1,000 Hz, 
with few fish hearing sounds above 4 kHz (Popper, 2008). It is believed 
that most fish have their best hearing sensitivity from 100 to 400 Hz 
(Popper, 2003b). Additionally, some clupeids (shad in the subfamily 
Alosinae) possess ultrasonic hearing (i.e., able to detect sounds above 
100,000 Hz) (Astrup, 1999). Permanent hearing loss, or permanent 
threshold shift has not been documented in fish. The sensory hair cells 
of the inner ear in fish can regenerate after they are damaged, unlike 
in mammals where sensory hair cells loss is permanent (Lombarte et al., 
1993; Smith et al., 2006). As a consequence, any hearing loss in fish 
may be as temporary as the timeframe required to repair or replace the 
sensory cells that were damaged or destroyed (e.g., Smith et al., 
2006).
    Potential direct injuries from non-impulsive sound sources, such as 
sonar, are unlikely because of the relatively lower peak pressures and 
slower rise times than potentially injurious sources such as 
explosives. Non-impulsive sources also lack the strong shock waves 
associated with an explosion. Therefore, direct injury is not likely to 
occur from exposure to non-impulsive sources such as sonar, vessel 
noise, or subsonic aircraft noise. Only a few fish species are able to 
detect high-frequency sonar and could have behavioral reactions or 
experience auditory masking during these activities. These effects are 
expected to be transient and long-term consequences for the population 
are not expected. MFAS is unlikely to impact fish species because most 
species are unable to detect sounds in this frequency range and vessels 
operating MFAS would be transiting an area (not stationary). While a 
large number of fish species may be able to detect low-frequency sonar 
and other active acoustic sources, low-frequency active usage is rare 
and mostly conducted in deeper waters. Overall effects to fish from 
non-impulsive sound sources would be localized and infrequent.
    Physical effects from pressure waves generated by underwater sounds 
(e.g. underwater explosions) could potentially affect fish within 
proximity of training activities. In particular, the rapid oscillation 
between high- and low-pressure peaks has the potential to burst the 
swim bladders and other gas-containing organs of fish (Keevin and 
Hemen, 1997). Sublethal effects, such as changes in behavior of fish, 
have been observed in several occasions as a result of noise produced 
by explosives (National Research Council of the National Academies, 
2003; Wright, 1982). If an individual fish were repeatedly exposed to 
sounds from underwater explosions that caused alterations in natural 
behavioral patterns or physiological stress, these impacts could lead 
to long-term consequences for the individual such as reduced survival, 
growth, or reproductive capacity. However, the time scale of individual 
explosions is very limited, and training exercises involving explosions 
are dispersed in space and time. Consequently, repeated exposure of 
individual fish to sounds from underwater explosions is not likely and 
most acoustic effects are expected to be short-term and localized. 
Long-term consequences for populations would not be expected.

Marine Mammal Avoidance

    Marine mammals may be temporarily displaced from areas where Navy 
training is occurring, but the area should be utilized again after the 
activities have ceased. Avoidance of an area can help the animal avoid 
further acoustic effects by avoiding or reducing further exposure. The 
intermittent or short duration of many activities should prevent 
animals from being exposed to stressors on a continuous basis (for the 
GOA TMAA, training activities will not occur continuously throughout 
the year, but rather, for a maximum of 21 days either once or twice 
annually). In areas of repeated and frequent acoustic disturbance, some 
animals may habituate or learn to tolerate the new baseline or 
fluctuations in noise level. While some animals may not return to an 
area, or may begin using an area differently due to training 
activities, most animals are expected to return to their usual 
locations and behavior.

Other Expected Effects

    Other sources that may affect marine mammal habitat were considered 
in the GOA DSEIS/OEIS and potentially include the introduction of fuel, 
debris, ordnance, and chemical residues into the water column. The 
majority of high-order explosions would occur at or above the surface 
of the ocean, and would have no impacts on sediments and minimal 
impacts on water quality. While disturbance or strike from an item 
falling through the water column is possible, it is unlikely because 
(1) objects sink slowly, (2) most projectiles are fired at targets (and 
hit those targets), and (3) animals are generally widely dispersed 
throughout the water column and over the Study Area. Chemical, 
physical, or biological changes in sediment or water quality would not 
be detectable. In the event of an ordnance failure, the energetic 
materials it contained would remain mostly intact. The explosive 
materials

[[Page 10003]]

in failed ordnance items and metal components from training would leach 
slowly and would quickly disperse in the water column. Chemicals from 
other explosives would not be introduced into the water column in large 
amounts and all torpedoes would be recovered following training 
activities, reducing the potential for chemical concentrations to reach 
levels that can affect sediment quality, water quality, or benthic 
habitats.

Preliminary Analysis and Negligible Impact Determination

    Negligible impact is ``an impact resulting from the specified 
activity that cannot be reasonably expected to, and is not reasonably 
likely to, adversely affect the species or stock through effects on 
annual rates of recruitment or survival'' (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes, alone, is not 
enough information on which to base an impact determination, as the 
severity of harassment may vary greatly depending on the context and 
duration of the behavioral response, many of which would not be 
expected to have deleterious impacts on the fitness of any individuals. 
In determining whether the expected takes will have a negligible 
impact, in addition to considering estimates of the number of marine 
mammals that might be ``taken,'' NMFS must consider other factors, such 
as the likely nature of any responses (their intensity, duration, 
etc.), the context of any responses (critical reproductive time or 
location, migration, etc.), as well as the number and nature (e.g., 
severity) of estimated Level A harassment takes, the number of 
estimated mortalities, and the status of the species. As a reminder, 
the GOA TMAA training activities will not occur continuously throughout 
the year, but rather, for a maximum of 21 days either once or twice 
annually).
    The Navy's specified activities have been described based on best 
estimates of the maximum amount of sonar and other acoustic source use 
or detonations that the Navy would conduct. There may be some 
flexibility in that the exact number of hours, items, or detonations 
may vary from year to year, but take totals are not authorized to 
exceed the 5-year totals indicated in Tables 12-13. We base our 
analysis and NID on the maximum number of takes authorized, although, 
as stated before, the number of takes are only a part of the analysis, 
which includes extensive qualitative consideration of other contextual 
factors that influence the degree of impact of the takes on the 
effected individuals. To avoid repetition, we provide some general 
analysis immediately below that applies to all the species listed in 
Tables 13, given that some of the anticipated effects (or lack thereof) 
of the Navy's training activities on marine mammals are expected to be 
relatively similar in nature. However, below that, we break our 
analysis into species, or groups of species where relevant similarities 
exist, to provide more specific information related to the anticipated 
effects on individuals or where there is information about the status 
or structure of any species that would lead to a differing assessment 
of the effects on the population.
    The Navy's take request is based on its model and post-model 
analysis. In the discussions below, the ``acoustic analysis'' refers to 
the Navy's modeling results and post-model analysis. The model 
calculates sound energy propagation from sonar, other active acoustic 
sources, and explosives during naval activities; the sound or impulse 
received by animat dosimeters representing marine mammals distributed 
in the area around the modeled activity; and whether the sound or 
impulse received by a marine mammal exceeds the thresholds for effects. 
The model estimates are then further analyzed to consider animal 
avoidance and implementation of highly effective mitigation measures to 
prevent Level A harassment, resulting in final estimates of effects due 
to Navy training and testing. NMFS provided input to the Navy on this 
process and the Navy's qualitative analysis is described in detail in 
Chapter 6 of its LOA application (http://www.nmfs.noaa.gov/pr/permits/incidental/militry.htm).
    Generally speaking, and especially with other factors being equal, 
the Navy and NMFS anticipate more severe effects from takes resulting 
from exposure to higher received levels (though this is in no way a 
strictly linear relationship throughout species, individuals, or 
circumstances) and less severe effects from takes resulting from 
exposure to lower received levels. The requested number of Level B 
takes does not equate to the number of individual animals the Navy 
expects to harass (which is lower), but rather to the instances of take 
(i.e., exposures above the Level B harassment threshold) that would 
occur. Additionally, these instances may represent either a very brief 
exposure (seconds) or, in some cases, longer durations of exposure 
within a day. Depending on the location, duration, and frequency of 
activities, along with the distribution and movement of marine mammals, 
individual animals may be exposed to impulse or non-impulse sounds at 
or above the Level B harassment threshold on multiple days. However, 
the Navy is currently unable to estimate the number of individuals that 
may be taken during training and testing activities. The model results 
estimate the total number of takes that may occur to a smaller number 
of individuals. While the model shows that an increased number of 
exposures may take place due to an increase in events/activities and 
ordnance, the types and severity of individual responses to training 
and testing activities are not expected to change.

Behavioral Harassment

    As discussed previously in this proposed rule, marine mammals can 
respond to LF/MFAS/HFAS in many different ways, a subset of which 
qualifies as behavioral harassment. As described in the proposed rule, 
the Navy uses the behavioral response function to quantify 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.
    Some of the lower level physiological stress responses discussed 
earlier would also likely co-occur with the predicted harassments, 
although these responses are more difficult to detect and fewer data 
exist relating these responses to specific received levels of sound. 
Level B takes, then, may have a stress-related physiological component 
as well; however, we would not expect the Navy's generally short-term, 
intermittent, and (in the case of sonar) transitory activities to 
create conditions of long-term, continuous noise leading to long-term 
physiological stress responses in marine mammals.
    The estimates calculated using the behavioral response function do 
not differentiate between the different types of potential reactions. 
Nor do the estimates provide information regarding the potential 
fitness or other biological consequences of the reactions on the 
affected individuals. We therefore consider the available scientific 
evidence to determine the likely nature of the modeled behavioral 
responses and the potential fitness consequences for affected 
individuals.

[[Page 10004]]

    For LF/MFAS/HFAS use in the GOA TMAA, the Navy provided information 
(Table 14) estimating the percentage of behavioral harassment that 
would occur within the 6-dB bins (without considering mitigation or 
avoidance). As mentioned above, an animal's exposure to a higher 
received level is more likely to result in a behavioral response that 
is more likely to adversely affect the health of the animal. As 
illustrated below, the majority (including about 72 percent for the 
most powerful ASW hull-mounted sonar, which is responsible for a large 
portion of the sonar takes) of calculated takes from MFAS result from 
exposures less than 156 dB. Less than 1 percent of the takes are 
expected to result from exposures above 174 dB. Specifically, given a 
range of behavioral responses that may be classified as Level B 
harassment, to the degree that higher received levels are expected to 
result in more severe behavioral responses, only a small percentage of 
the anticipated Level B harassment from Navy activities might 
necessarily be expected to potentially result in more severe responses, 
especially when the distance from the source at which the levels below 
are received is considered (see Table 14). Marine mammals are able to 
discern the distance of a given sound source, and given other equal 
factors (including received level), they have been reported to respond 
more to sounds that are closer (DeRuiter et al., 2013). Further, the 
estimated number of responses do not reflect either the duration or 
context of those anticipated responses, some of which will be of very 
short duration, and other factors should be considered when predicting 
how the estimated takes may affect individual fitness. A recent study 
by Moore and Barlow (2013) emphasizes the importance of context (e.g., 
behavioral state of the animals, distance from the sound source, etc.) 
in evaluating behavioral responses of marine mammals to acoustic 
sources.

                                  Table 14--Non-Impulsive Ranges in 6-dB bins and Percentage of Behavioral Harassments
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Sonar bin MF1 (e.g., SQS-53;  ASW     Sonar bin MF4 (e.g., AQS-22;  ASW    Sonar Bin MF5  (e.g., SSQ-62;  ASW
                                                hull  mounted sonar)                     dipping  sonar)                          sonobuoy)
                                       -----------------------------------------------------------------------------------------------------------------
                                                             Percentage of                         Percentage of                         Percentage of
            Received level              Distance at which      behavioral     Distance at which      behavioral     Distance at which      behavioral
                                           levels occur       harassments        levels occur       harassments        levels occur       harassments
                                        within radius  of     occurring at    within radius  of     occurring at    within radius  of     occurring at
                                           source  (m)        given levels       source  (m)        given levels       source  (m)        given levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Low Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
120 <= SPL <126.......................    178,750-156,450               0.00     100,000-92,200               0.00      22,800-15,650               0.00
126 <= SPL <132.......................    156,450-147,500               0.00      92,200-55,050               0.11      15,650-11,850               0.05
132 <= SPL <138.......................    147,500-103,700               0.21      55,050-46,550               1.08       11,850-6,950               2.84
138 <= SPL <144.......................     103,700-97,950               0.33      46,550-15,150              35.69        6,950-3,600              16.04
144 <= SPL <150.......................      97,950-55,050              13.73       15,150-5,900              26.40        3,600-1,700              33.63
150 <= SPL <156.......................      55,050-49,900               5.28        5,900-2,700              17.43          1,700-250              44.12
156 <= SPL <162.......................      49,900-10,700              72.62        2,700-1,500               9.99            250-100               2.56
162 <= SPL <168.......................       10,700-4,200               6.13          1,500-200               9.07            100-<50               0.76
168 <= SPL <174.......................        4,200-1,850               1.32            200-100               0.18                <50               0.00
174 <= SPL <180.......................          1,850-850               0.30            100-<50               0.05                <50               0.00
180 <= SPL <186.......................            850-400               0.07                <50               0.00                <50               0.00
186 <= SPL <192.......................            400-200               0.01                <50               0.00                <50               0.00
192 <= SPL <198.......................            200-100               0.00                <50               0.00                <50               0.00
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Mid Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
120 <= SPL <126.......................    179,400-156,450               0.00     100,000-92,200               0.00      23,413-16,125               0.00
126 <= SPL <132.......................    156,450-147,500               0.00      92,200-55,050               0.11      16,125-11,500               0.06
132 <= SPL <138.......................    147,500-103,750               0.21      55,050-46,550               1.08       11,500-6,738               2.56
138 <= SPL <144.......................     103,750-97,950               0.33      46,550-15,150              35.69        6,738-3,825              13.35
144 <= SPL <150.......................      97,950-55,900              13.36       15,150-5,900              26.40        3,825-1,713              37.37
150 <= SPL <156.......................      55,900-49,900               6.12        5,900-2,700              17.43          1,713-250              42.85
156 <= SPL <162.......................      49,900-11,450              71.18        2,700-1,500               9.99            250-150               1.87
162 <= SPL <168.......................       11,450-4,350               7.01          1,500-200               9.07            150-<50               1.93
168 <= SPL <174.......................        4,350-1,850               1.42            200-100               0.18                <50               0.00
174 <= SPL <180.......................          1,850-850               0.29            100-<50               0.05                <50               0.00
180 <= SPL <186.......................            850-400               0.07                <50               0.00                <50               0.00
186 <= SPL <192.......................            400-200               0.01                <50               0.00                <50               0.00
192 <= SPL <198.......................            200-100               0.00                <50               0.00                <50               0.00
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: (1) ASW = anti-submarine warfare, m = meters, SPL = sound pressure level; (2) Odontocete behavioral response function is also used for high-
  frequency cetaceans, phocid seals, otariid seals and sea lions, and sea otters.

    Although the Navy has been monitoring to discern the effects of LF/
MFAS/HFAS on marine mammals since 2006, and research on the effects of 
MFAS is advancing, our understanding of exactly how marine mammals in 
the Study Area will respond to LF/MFAS/HFAS is still improving. The 
Navy has submitted more than 80 reports, including Major Exercise 
Reports, Annual Exercise Reports, and Monitoring Reports, documenting 
hundreds of thousands of marine mammals across Navy range complexes, 
and there are only two instances of overt behavioral disturbances that 
have been observed. One cannot conclude from these results that marine 
mammals were not harassed from MFAS/HFAS, as a portion of animals 
within the area of concern were not seen (especially those more 
cryptic, deep-diving species, such as beaked whales or Kogia spp.), the 
full series of behaviors that would more accurately show an important 
change is not typically seen (i.e., only the surface behaviors are 
observed), and some of the non-biologist watchstanders might not be 
well-qualified to characterize behaviors. However, one can say that the 
animals that were observed did not respond in any of the obviously more 
severe ways, such as panic, aggression, or anti-predator response.

[[Page 10005]]

Diel Cycle

    As noted previously, many animals perform vital functions, such as 
feeding, resting, traveling, and socializing on a diel cycle (24-hour 
cycle). Behavioral reactions to noise exposure (when taking place in a 
biologically important context, such as disruption of critical life 
functions, displacement, or avoidance of important habitat) are more 
likely to be significant if they last more than one diel cycle or recur 
on subsequent days (Southall et al., 2007). Consequently, a behavioral 
response lasting less than one day and not recurring on subsequent days 
is not considered severe unless it could directly affect reproduction 
or survival (Southall et al., 2007). Note that there is a difference 
between multiple-day substantive behavioral reactions and multiple-day 
anthropogenic activities. For example, just because an at-sea exercise 
lasts for multiple days does not necessarily mean that individual 
animals are either exposed to those exercises for multiple days or, 
further, exposed in a manner resulting in a sustained multiple day 
substantive behavioral response. Large multi-day Navy exercises, such 
as those proposed in the GOA TMAA, typically include vessels that are 
continuously moving at speeds typically 10-15 knots, or higher, and 
likely cover large areas that are relatively far from shore, in 
addition to the fact that marine mammals are moving as well, which 
would make it unlikely that the same animal could remain in the 
immediate vicinity of the ship for the entire duration of the exercise. 
Additionally, the Navy does not necessarily operate active sonar the 
entire time during an exercise. While it is certainly possible that 
these sorts of exercises could overlap with individual marine mammals 
multiple days in a row at levels above those anticipated to result in a 
take, because of the factors mentioned above, it is considered unlikely 
for the majority of takes. It does not mean that a behavioral response 
is necessarily sustained for multiple days, but instead necessitates 
the consideration of likely duration and context to assess any effects 
on the individual's fitness.
    Durations for non-impulsive activities utilizing tactical sonar 
sources vary and are fully described in Appendix A of the GOA DSEIS/
OEIS. ASW training exercises using MFAS/HFAS proposed for the GOA TMAA 
generally last for 2-16 hours, and may have intervals of non-activity 
in between. Because of the need to train in a large variety of 
situations (in the case of the GOA TMAA, complex bathymetric and 
oceanographic conditions include a continental shelf, submarine 
canyons, seamounts, and fresh water infusions from multiple sources), 
the Navy does not typically conduct successive ASW exercises in the 
same locations. Given the average length of ASW exercises (times of 
continuous sonar use) and typical vessel speed, combined with the fact 
that the majority of the cetaceans in the GOA TMAA Study Area would not 
likely remain in an area for successive days, it is unlikely that an 
animal would be exposed to MFAS/HFAS at levels likely to result in a 
substantive response that would then be carried on for more than one 
day or on successive days.
    With the exception of SINKEXs, the planned explosive exercises for 
the GOA TMAA are of a short duration (1-6 hours). Although explosive 
exercises may sometimes be conducted in the same general areas 
repeatedly, because of their short duration and the fact that they are 
in the open ocean and animals can easily move away, it is similarly 
unlikely that animals would be exposed for long, continuous amounts of 
time. Although SINKEXs may last for up to 48 hrs, only two are planned 
annually for the GOA TMAA training activities, they are stationary and 
conducted in deep, open water (where fewer marine mammals would 
typically be expected to be randomly encountered), and they have a 
rigorous monitoring and shutdown procedures, all of which make it 
unlikely that individuals would be exposed to the exercise for extended 
periods or on consecutive days.

TTS

    As mentioned previously, TTS can last from a few minutes to days, 
be of varying degree, and occur across various frequency bandwidths, 
all of which determine the severity of the impacts on the affected 
individual, which can range from minor to more severe. The TTS 
sustained by an animal is primarily classified by three 
characteristics:
    1. Frequency--Available data (of mid-frequency hearing specialists 
exposed to mid- or high-frequency sounds; Southall et al., 2007) 
suggest that most TTS occurs in the frequency range of the source up to 
one octave higher than the source (with the maximum TTS at \1/2\ octave 
above). The more powerful MF sources used have center frequencies 
between 3.5 and 8 kHz and the other unidentified MF sources are, by 
definition, less than 10 kHz, which suggests that TTS induced by any of 
these MF sources would be in a frequency band somewhere between 
approximately 2 and 20 kHz. There are fewer hours of HF source use and 
the sounds would attenuate more quickly, plus they have lower source 
levels, but if an animal were to incur TTS from these sources, it would 
cover a higher frequency range (sources are between 20 and 100 kHz, 
which means that TTS could range up to 200 kHz; however, HF systems are 
typically used less frequently and for shorter time periods than 
surface ship and aircraft MF systems, so TTS from these sources is even 
less likely). TTS from explosives would be broadband. Vocalization data 
for each species, which would inform how TTS might specifically 
interfere with communications with conspecifics, was provided in the 
LOA application.
    2. Degree of the shift (i.e., by how many dB the sensitivity of the 
hearing is reduced)--Generally, both the degree of TTS and the duration 
of TTS will be greater if the marine mammal is exposed to a higher 
level of energy (which would occur when the peak dB level is higher or 
the duration is longer). The threshold for the onset of TTS was 
discussed previously in this proposed rule. An animal would have to 
approach closer to the source or remain in the vicinity of the sound 
source appreciably longer to increase the received SEL, which would be 
difficult considering the Lookouts and the nominal speed of an active 
sonar vessel (10-15 knots). In the TTS studies (see Threshold Shift 
section), some using exposures of almost an hour in duration or up to 
217 SEL, most of the TTS induced was 15 dB or less, though Finneran et 
al. (2007) induced 43 dB of TTS with a 64-second exposure to a 20 kHz 
source. However, MFAS emits a ping typically every 50 seconds, and 
incurring those levels of TTS is highly unlikely.
    3. Duration of TTS (recovery time)--In the TTS laboratory studies 
(see Threshold Shift section), some using exposures of almost an hour 
in duration or up to 217 SEL, almost all individuals recovered within 1 
day (or less, often in minutes), although in one study (Finneran et 
al., 2007), recovery took 4 days.
    Based on the range of degree and duration of TTS reportedly induced 
by exposures to non-pulse sounds of energy higher than that to which 
free-swimming marine mammals in the field are likely to be exposed 
during MFAS/HFAS training exercises in the GOA TMAA, it is unlikely 
that marine mammals would ever sustain a TTS from MFAS that alters 
their sensitivity by more than 20 dB for more than a few days (and any 
incident of TTS would likely be far less severe due to the short 
duration of the majority of the exercises and the speed of a typical 
vessel). Also, for the same reasons discussed in the Diel Cycle 
section, and because of the

[[Page 10006]]

short distance within which animals would need to approach the sound 
source, it is unlikely that animals would be exposed to the levels 
necessary to induce TTS in subsequent time periods such that their 
recovery is impeded. Additionally, though the frequency range of TTS 
that marine mammals might sustain would overlap with some of the 
frequency ranges of their vocalization types, the frequency range of 
TTS from MFAS (the source from which TTS would most likely be sustained 
because the higher source level and slower attenuation make it more 
likely that an animal would be exposed to a higher received level) 
would not usually span the entire frequency range of one vocalization 
type, much less span all types of vocalizations or other critical 
auditory cues. If impaired, marine mammals would typically be aware of 
their impairment and are sometimes able to implement behaviors to 
compensate (see Acoustic Masking or Communication Impairment section), 
though these compensations may incur energetic costs.

Acoustic Masking or Communication Impairment

    Masking only occurs during the time of the signal (and potential 
secondary arrivals of indirect rays), versus TTS, which continues 
beyond the duration of the signal. Standard MFAS typically pings every 
50 seconds for hull-mounted sources. For the sources for which we know 
the pulse length, most are significantly shorter than hull-mounted 
active sonar, on the order of several microseconds to tens of 
microseconds. For hull-mounted active sonar, though some of the 
vocalizations that marine mammals make are less than one second long, 
there is only a 1 in 50 chance that they would occur exactly when the 
ping was received, and when vocalizations are longer than one second, 
only parts of them are masked. Alternately, when the pulses are only 
several microseconds long, the majority of most animals' vocalizations 
would not be masked. Masking effects from MFAS/HFAS are expected to be 
minimal. If masking or communication impairment were to occur briefly, 
it would be in the frequency range of MFAS, which overlaps with some 
marine mammal vocalizations; however, it would likely not mask the 
entirety of any particular vocalization, communication series, or other 
critical auditory cue, because the signal length, frequency, and duty 
cycle of the MFAS/HFAS signal does not perfectly mimic the 
characteristics of any marine mammal's vocalizations. The other sources 
used in Navy training and testing, many of either higher frequencies 
(meaning that the sounds generated attenuate even closer to the source) 
or lower amounts of operation, are similarly not expected to result in 
masking.

PTS, Injury, or Mortality

    NMFS believes that many marine mammals would deliberately avoid 
exposing themselves to the received levels of active sonar necessary to 
induce injury by moving away from or at least modifying their path to 
avoid a close approach. Additionally, in the unlikely event that an 
animal approaches the sonar vessel at a close distance, NMFS believes 
that the mitigation measures (i.e., shutdown/powerdown zones for MFAS/
HFAS) would typically ensure that animals would not be exposed to 
injurious levels of sound. As discussed previously, the Navy utilizes 
both aerial (when available) and passive acoustic monitoring (during 
all ASW exercises) in addition to watchstanders on vessels to detect 
marine mammals for mitigation implementation.
    If a marine mammal is able to approach a surface vessel within the 
distance necessary to incur PTS, the likely speed of the vessel 
(nominal 10-15 knots) would make it very difficult for the animal to 
remain in range long enough to accumulate enough energy to result in 
more than a mild case of PTS. As mentioned previously and in relation 
to TTS, the likely consequences to the health of an individual that 
incurs PTS can range from mild to more serious dependent upon the 
degree of PTS and the frequency band it is in, and many animals are 
able to compensate for the shift, although it may include energetic 
costs. Only 5 Level A (PTS) takes per year are predicted from GOA 
training activities, and these are all Dall's porpoise--not large whale 
species or beaked whales. We also assume that the acoustic exposures 
sufficient to trigger onset PTS (or TTS) would be accompanied by 
physiological stress responses, although the sound characteristics that 
correlate with specific stress responses in marine mammals are poorly 
understood. As discussed above for Behavioral Harassment, we would not 
expect the Navy's generally short-term, intermittent, and (in the case 
of sonar) transitory activities to create conditions of long-term, 
continuous noise leading to long-term physiological stress responses in 
marine mammals. No other injurious takes or mortality are predicted. As 
discussed previously, marine mammals (especially beaked whales) could 
potentially respond to MFAS at a received level lower than the injury 
threshold in a manner that indirectly results in the animals stranding. 
The exact mechanism of this potential response, behavioral or 
physiological, is not known. When naval exercises have been associated 
with strandings in the past, it has typically been when three or more 
vessels are operating simultaneously, in the presence of a strong 
surface duct, and in areas of constricted channels, semi-enclosed 
areas, and/or steep bathymetry. While these features certainly do not 
define the only factors that can contribute to a stranding, and while 
they need not all be present in their aggregate to increase the 
likelihood of a stranding, it is worth noting that they are not all 
present in the GOA TMAA, which only has a strong surface duct present 
during the winter, and does not have bathymetry or constricted channels 
of the type that have been present in the sonar associated strandings. 
When this is combined with consideration of the number of hours of 
active sonar training that will be conducted and the total duration of 
all training exercises (a maximum of 21 days once or twice a year), we 
believe that the probability is small that this will occur. Lastly, an 
active sonar shutdown protocol for strandings involving live animals 
milling in the water minimizes the chances that these types of events 
turn into mortalities.
    As stated previously, there have been no recorded Navy vessel 
strikes of any marine mammals during training in the GOA Study Area to 
date, nor were takes by injury or mortality resulting from vessel 
strike predicted in the Navy's analysis.

Group and Species-Specific Analysis

    Predicted effects on marine mammals from exposures to sonar and 
other active acoustic sources and explosions during annual training 
activities are shown in Table 13. The vast majority of predicted 
exposures (greater than 99 percent) are expected to be Level B 
harassment (non-injurious TTS and behavioral reactions) from sonar and 
other active acoustic sources at relatively low received levels (Table 
14). The acoustic analysis predicts the majority of marine mammal 
species in the Study Area would not be exposed to explosive (impulsive) 
sources associated with training activities. Only Dall's porpoise is 
predicted to have Level B (TTS) exposures resulting from explosives, 
and only a limited number (5) of Dall's porpoise are expected to have 
injurious take (PTS) resulting from sonar and other active acoustic 
sources and

[[Page 10007]]

explosions. There are no lethal takes predicted for any marine mammal 
species for the GOA activities.
    The analysis below may in some cases (e.g., mysticetes, porpoises, 
pinnipeds) address species collectively if they occupy the same 
functional hearing group (i.e., low-, mid-, and high-frequency 
cetaceans and pinnipeds in water), have similar hearing capabilities, 
and/or are known to generally behaviorally respond similarly to 
acoustic stressors. Where there are meaningful differences between 
species or stocks in anticipated individual responses to activities, 
impact of expected take on the population due to differences in 
population status, or impacts on habitat, they will either be described 
within the section or the species will be included as a separate sub-
section.
    Mysticetes--The Navy's acoustic analysis predicts that 2,923 
instances of Level B harassmant of mysticete whales may occur in the 
Study Area each year from sonar and other active acoustic sources 
during training activities. Annual species-specific take estimates are 
as follows: 7 North Pacific right whales (Eastern North Pacific stock), 
139 humpback whales (Central North Pacific and Western North Pacific 
stocks), 95 blue whales (Eastern North Pacific stock), 2,582 fin whales 
(Northeast Pacific stock), 13 sei whales (Eastern North Pacific stock), 
and 87 minke whales (Alaska stock). Of these species, humpback, blue, 
fin, sei, and North Pacific right whales are listed as endangered under 
the ESA and depleted under the MMPA. NMFS is currently engaged in an 
internal Section 7 consultation under the ESA and the outcome of that 
consultation will further inform our final decision. Based on the 
distribution information presented in the LOA application, it is highly 
unlikely that gray whales would be encountered in the Study Area during 
events involving use of sonar and other active acoustic sources. The 
acoustic analysis did not predict any takes of gray whales and NMFS is 
not authorizing any takes of this species.
    Generally, these represent a limited number of takes relative to 
population estimates for most mysticete stocks in the Study Area (Table 
6). When the numbers of behavioral takes are compared to the estimated 
stock abundance and if one assumes that each take happens to a separate 
animal, less than approximately 20 percent of each of these stocks 
(with the exception of the Northeast Pacific stock of fin whale and the 
Alaska stock of minke whale for which there currently are no reliable 
population estimates because only portions of the stocks' range have 
been surveyed [Muto and Angliss, 2015]) would be behaviorally harassed 
during the course of a year. Because the estimates given above 
represent the total number of exposures and not necessarily the number 
of individuals exposed, it is more likely that fewer individuals would 
be taken, but a subset would be taken more than one time per year. In 
the ocean, the use of sonar and other active acoustic sources is 
transient and is unlikely to repeatedly expose the same population of 
animals over a short period.
    Level B harassment takes are anticipated to be in the form of TTS 
and behavioral reactions and no injurious takes of North Pacific right, 
humpback, blue, fin, minke, or sei whales from sonar and other active 
acoustic stressors or explosives are expected. The majority of acoustic 
effects to mysticetes from sonar and other active sound sources during 
training activities would be primarily from anti-submarine warfare 
events involving surface ships and hull mounted sonar. Research and 
observations show that if mysticetes are exposed to sonar or other 
active acoustic sources they may react in a number of ways depending on 
the characteristics of the sound source, their experience with the 
sound source, and whether they are migrating or on seasonal grounds 
(i.e., breeding or feeding). Reactions may include alerting, breaking 
off feeding dives and surfacing, diving or swimming away, or no 
response at all (Richardson, 1995; Nowacek, 2007; Southall et al., 
2007; Finneran and Jenkins, 2012). Richardson et al. (1995) noted that 
avoidance (temporary displacement of an individual from an area) 
reactions are the most obvious manifestations of disturbance in marine 
mammals. Avoidance is qualitatively different from the startle or 
flight response, but also differs in the magnitude of the response 
(i.e., directed movement, rate of travel, etc.). Oftentimes avoidance 
is temporary, and animals return to the area once the noise has ceased. 
Additionally, migrating animals may ignore a sound source, or divert 
around the source if it is in their path.
    Specific to U.S. Navy systems using low frequency sound, studies 
were undertaken in 1997-98 pursuant to the Navy's Low Frequency Sound 
Scientific Research Program. These studies found only short-term 
responses to low frequency sound by mysticetes (fin, blue, and humpback 
whales) including changes in vocal activity and avoidance of the source 
vessel (Clark, 2001; Miller et al., 2000; Croll et al., 2001; Fristrup 
et al., 2003; Nowacek et al., 2007). Baleen whales exposed to moderate 
low-frequency signals demonstrated no variation in foraging activity 
(Croll et al., 2001). Low-frequency signals of the Acoustic Thermometry 
of Ocean Climate sound source were not found to affect dive times of 
humpback whales in Hawaiian waters (Frankel and Clark, 2000).
    Specific to mid-frequency sound, studies by Melc[oacute]n et al. 
(2012) in the Southern California Bight found that the likelihood of 
blue whale low-frequency calling (usually associated with feeding 
behavior) decreased with an increased level of MFAS, beginning at a SPL 
of approximately 110-120 dB re 1 [mu]Pa. However, 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. 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 MFAS but that those 
responses were mild and there was a quick return to their baseline 
activity (Southall et al., 2011; Southall et al., 2012b). Blue whales 
responded to a mid-frequency sound source, with a source level between 
160 and 210 dB re 1 [mu]Pa at 1 m and a received sound level up to 160 
dB re 1 [mu]Pa, by exhibiting generalized avoidance responses and 
changes to dive behavior during the exposure experiments (CEE) 
(Goldbogen et al., 2013). However, reactions were not consistent across 
individuals based on received sound levels alone, and likely were the 
result of a complex interaction between sound exposure factors such as 
proximity to sound source and sound type (MFAS simulation vs. pseudo-
random noise), environmental conditions, and behavioral state. Surface 
feeding whales did not show a change in behavior during CEEs, but deep 
feeding and non-feeding whales showed temporary reactions that quickly 
abated after sound exposure. Distances of the sound source from the 
whales during CEEs were sometimes less than a mile. Blue whales have 
been documented exhibiting a range of foraging strategies for 
maximizing feeding dependent on the density of their prey at a given 
location (Goldbogen et al., 2015), so it may be that a temporary 
behavioral reaction or avoidance of a location where feeding was 
occurring is not meaningful to the life history of an animal. The 
preliminary findings from Goldbogen et al. (2013) and Melc[oacute]n et 
al. (2012) are generally consistent with

[[Page 10008]]

the Navy's criteria and thresholds for predicting behavioral effects to 
mysticetes from sonar and other active acoustic sources used in the 
quantitative acoustic effects analysis for GOA. The Navy's behavioral 
response function predicts the probability of a behavioral response 
that rises to a Level B take for individuals exposed to a received SPL 
of 120 dB re 1 [mu]Pa or greater, with an increasing probability of 
reaction with increased received level as demonstrated in Melc[oacute]n 
et al. (2012).
    High-frequency systems are notably outside of mysticetes' ideal 
hearing and vocalization range and it is unlikely that they would cause 
a significant behavioral reaction.
    Most Level B harassments to mysticetes from sonar in the Study Area 
would result from received levels less than 156 dB SPL. Therefore, the 
majority of Level B takes are expected to be in the form of milder 
responses (i.e., lower-level exposures that still rise to the level of 
take, but would likely be less severe in the range of responses that 
qualify as take) of a generally short duration. As mentioned earlier in 
this section, we anticipate more severe effects from takes when animals 
are exposed to higher received levels. Most low-frequency (mysticetes) 
cetaceans observed in studies usually avoided sound sources at levels 
of less than or equal to 160 dB re 1[mu]Pa. Occasional milder 
behavioral reactions are unlikely to cause long-term consequences for 
individual animals or populations. Even if sound exposure were to be 
concentrated in a relatively small geographic area over a long period 
of time (e.g., days or weeks during major training exercises), we would 
expect that some individual whales would avoid areas where exposures to 
acoustic stressors are at higher levels. For example, Goldbogen et al. 
(2013) indicated some horizontal displacement of deep foraging blue 
whales in response to simulated MFA sonar. Given these animal's 
mobility and large ranges, we would expect these individuals to 
temporarily select alternative foraging sites nearby until the exposure 
levels in their initially selected foraging area have decreased. 
Therefore, even temporary displacement from initially selected foraging 
habitat is not expected to impact the fitness of any individual animals 
because we would expect equivalent foraging to be available in close 
proximity. Because we do not expect any fitness consequences from any 
individual animals, we do not expect any population level effects from 
these behavioral responses.
    As explained above, recovery from a threshold shift (TTS) can take 
a few minutes to a few days, depending on the exposure duration, sound 
exposure level, and the magnitude of the initial shift, with larger 
threshold shifts and longer exposure durations requiring longer 
recovery times (Finneran et al., 2005; Finneran and Schlundt, 2010; 
Mooney et al., 2009a; Mooney et al., 2009b). However, large threshold 
shifts are not anticipated for these activities because of the 
unlikelihood that animals will remain within the ensonified area (due 
to the short duration of the majority of exercises, the speed of the 
vessels, and the short distance within which the animal would need to 
approach the sound source) at high levels for the duration necessary to 
induce larger threshold shifts. Threshold shifts do not necessarily 
affect all hearing frequencies equally, so some threshold shifts may 
not interfere with an animal's hearing of biologically relevant sounds. 
Furthermore, the implementation of mitigation and the sightability of 
mysticetes (due to their large size) reduces the potential for a 
significant behavioral reaction or a threshold shift to occur.
    Overall, the number of predicted behavioral reactions is low and 
occasional behavioral reactions are unlikely to cause long-term 
consequences for individual animals or populations. This assessment of 
long-term consequences is based in part on findings from ocean areas 
where the Navy has been intensively training and testing with sonar and 
other active acoustic sources for decades. While there are many factors 
such as the end of large-scale commercial whaling complicating any 
analysis, there is no data suggesting any long-term consequences to 
mysticetes from exposure to sonar and other active acoustic sources. On 
the contrary, there are findings suggesting mysticete populations are 
increasing in the two primary locations (Southern California and 
Hawaii) where the Navy's most intensively used range complexes are 
located. These findings include: (1) Calambokidis et al. (2009b) 
indicating a significant upward trend in abundance of for blue whales 
in Southern California; (2) the recovery of gray whales that migrate 
through the Navy's SOCAL Range Complex twice a year; (3) work by Moore 
and Barlow (2011) indicating evidence of increasing fin whale abundance 
in the California Current area, which includes the SOCAL Range Complex; 
(4) the range expansion and increasing presence of Bryde's whales south 
of Point Conception in Southern California (Kerosky et al. 2012); and 
(5) the ocean area contained within the Hawaii Range Complex continuing 
to function as a critical breeding, calving, and nursing area to the 
point at which the overall humpback whale population in the North 
Pacific is now greater than some prior estimates of pre-whaling 
abundance (Barlow et al., 2011). The implementation of mitigation and 
the sightability of mysticetes (due to their large size) reduces the 
potential for a significant behavioral reaction or a threshold shift to 
occur. Furthermore, there is no designated critical habitat for 
mysticetes in the Study Area. As discussed in the Consideration of 
Time/Area Limitations section of this rule, review of the NMFS-
identified feeding and migration areas showed there is only minimal (<1 
percent) spatial overlap with the GOA TMAA and the North Pacific right 
whale feeding area southeast of Kodiak Island and minimal (<1 percent) 
spatial overlap with a small portion of the gray whale migration area 
offshore of Kenai Peninsula (Ferguson et al., 2015b). Those areas of 
overlap at the corners of the GOA TMAA are very unlikely to have any 
Navy training activity. Further, the grey whale migration area is only 
applicable in the early spring and late fall, while training activities 
are proposed for May to October (with June/July the main months of 
training, historically). Therefore, it is very unlikely there would be 
an effect to feeding or migrating activities if right whales or gray 
whales were present. Additionally, appropriate mitigation measures (as 
detailed in the Mitigation section above) would be implemented for any 
detected marine mammals and thus further reducing the potential for the 
feeding or migration activities to be affected. The Navy proposes to 
monitor use of active sonar within the North Pacific right whale 
feeding area and gray whale migration areas, to the extent that active 
sonar training does occur in these areas, and to report that use to 
NMFS in classified annual reports (see Proposed Reporting) to inform 
future adaptive management of activities within the GOA TMAA.
    Consequently, the GOA TMAA activities are not expected to adversely 
impact rates of recruitment or survival of mysticete whales.
    Sperm Whales--The Navy's acoustic analysis indicates that 197 
instances of Level B harassment of sperm whales (North Pacific stock; 
currently there are no reliable abundance estimates for this stock 
[Muto and Angliss, 2015]) may occur in the Study Area each year from 
sonar or other active acoustic stressors during training activities. 
Sperm whales are listed as endangered under the ESA

[[Page 10009]]

and depleted under the MMPA. NMFS is currently engaged in an internal 
Section 7 consultation under the ESA and the outcome of that 
consultation will further inform our final decision. These Level B 
takes are anticipated to be in the form of TTS and behavioral reactions 
and no injurious takes of sperm whales from sonar and other active 
acoustic stressors or explosives are requested or proposed for 
authorization. Sperm whales have shown resilience to acoustic and human 
disturbance, although they may react to sound sources and activities 
within a few kilometers. Sperm whales that are exposed to activities 
that involve the use of sonar and other active acoustic sources may 
alert, ignore the stimulus, avoid the area by swimming away or diving, 
or display aggressive behavior (Richardson, 1995; Nowacek, 2007; 
Southall et al., 2007; Finneran and Jenkins, 2012). Some (but not all) 
sperm whale vocalizations might overlap with the MFAS/HFAS TTS 
frequency range, which could temporarily decrease an animal's 
sensitivity to the calls of conspecifics or returning echolocation 
signals. However, as noted previously, NMFS does not anticipate TTS of 
a long duration or severe degree to occur as a result of exposure to 
MFAS/HFAS. Recovery from a threshold shift (TTS) can take a few minutes 
to a few days, depending on the exposure duration, sound exposure 
level, and the magnitude of the initial shift, with larger threshold 
shifts and longer exposure durations requiring longer recovery times 
(Finneran et al., 2005; Mooney et al., 2009a; Mooney et al., 2009b; 
Finneran and Schlundt, 2010). Large threshold shifts are not 
anticipated for these activities because of the unlikelihood that 
animals will remain within the ensonified area (due to the short 
duration of the majority of exercises, the speed of the vessels, and 
the short distance within which the animal would need to approach the 
sound source) at high levels for the duration necessary to induce 
larger threshold shifts. Threshold shifts do not necessarily affect all 
hearing frequencies equally, so some threshold shifts may not interfere 
with an animal's hearing of biologically relevant sounds. No sperm 
whales are predicted to be exposed to MFAS/HFAS sound levels associated 
with PTS or injury.
    The majority of Level B takes are expected to be in the form of 
mild responses (low-level exposures) and of a generally short duration. 
Relative to the population size, this activity is anticipated to result 
only in a limited number of Level B harassment takes. Because the 
estimates given above represent the total number of exposures and not 
necessarily the number of individuals exposed, it is more likely that 
fewer individuals would be taken, but a subset would be taken more than 
one time per year. In the ocean, the use of sonar and other active 
acoustic sources is transient and is unlikely to repeatedly expose the 
same population of animals over a short period. Overall, the number of 
predicted behavioral reactions are unlikely to cause long-term 
consequences for individual animals or populations. The GOA activities 
are not expected to occur in an area/time of specific importance for 
reproductive, feeding, or other known critical behaviors for sperm 
whales, and there is no designated critical habitat in the Study Area. 
Consequently, the activities are not expected to adversely impact 
annual rates of recruitment or survival of sperm whales.
    Dolphins and Small Whales--The Navy's acoustic analysis predicts 
the following instances of Level B harassment of delphinids (dolphins 
and small whales) each year from sonar and other active acoustic 
sources associated with training activities in the Study Area: 762 
killer whales (Alaska Resident; Eastern North Pacific Offshore; AT1 
Transient; and GOA, Aleutian Island, and Bearing Sea Transient stocks) 
and 1,963 Pacific white-sided dolphins (North Pacific stock). These 
represent a limited number of takes relative to population estimates 
for delphinid stocks in the Study Area (Table 6). When the numbers of 
behavioral takes are compared to the estimated stock abundance and if 
one assumes that each take happens to a separate animal, less than 25 
percent of each of the killer whale stocks and less than 8 percent of 
the North Pacific stock of Pacific white-sided dolphin would be 
behaviorally harassed during the course of a year. More likely, 
slightly fewer individuals would be harassed, but a subset would be 
harassed more than one time during the course of the year.
    All of these takes are anticipated to be in the form of behavioral 
harassment (TTS and behavioral reaction) and no injurious takes of 
delphinids from sonar and other active acoustic stressors or explosives 
are requested or proposed for authorization. Further, the majority of 
takes are anticipated to be by behavioral harassment in the form of 
mild responses. Research and observations show that if delphinids are 
exposed to sonar or other active acoustic sources they may react in a 
number of ways depending on their experience with the sound source and 
what activity they are engaged in at the time of the acoustic exposure. 
Delphinids may not react at all until the sound source is approaching 
within a few hundred meters to within a few kilometers depending on the 
environmental conditions and species. Delphinids that are exposed to 
activities that involve the use of sonar and other active acoustic 
sources may alert, ignore the stimulus, change their behaviors or 
vocalizations, avoid the sound source by swimming away or diving, or be 
attracted to the sound source (Richardson, 1995; Nowacek, 2007; 
Southall et al., 2007; Finneran and Jenkins, 2012). Research has 
demonstrated that Alaska Resident killer whales may routinely move over 
long large distances (Andrews and Matkin, 2014; Fearnbach et al., 
2013). In a similar documented long-distance movement, an Eastern North 
Pacific Offshore stock killer whale tagged off San Clemente Island, 
California, moved (over a period of 147 days) to waters off northern 
Mexico, then north to Cook Inlet, Alaska, and finally (when the tag 
ceased transmitting) to coastal waters off Southeast Alaska (Falcone 
and Schorr, 2014). Given these findings, temporary displacement due to 
avoidance of training activities are therefore unlikely to have 
biological significance to individual animals.
    Delphinid species generally travel in large pods and should be 
visible from a distance in order to implement mitigation measures and 
reduce potential impacts. Many of the recorded delphinid vocalizations 
overlap with the MFAS/HFAS TTS frequency range (2-20 kHz); however, as 
noted above, NMFS does not anticipate TTS of a serious degree or 
extended duration to occur as a result of exposure to MFAS/HFAS. 
Recovery from a threshold shift (TTS) can take a few minutes to a few 
days, depending on the exposure duration, sound exposure level, and the 
magnitude of the initial shift, with larger threshold shifts and longer 
exposure durations requiring longer recovery times (Finneran et al., 
2005; Finneran and Schlundt, 2010; Mooney et al., 2009a; Mooney et al., 
2009b). However, large threshold shifts are not anticipated for these 
activities because of the unlikelihood that animals will remain within 
the ensonified area (due to the short duration of the majority of 
exercises, the speed of the vessels, and the short distance within 
which the animal would need to approach the sound source) at high 
levels for the duration necessary to induce larger threshold shifts. 
Threshold shifts do not necessarily affect all hearing frequencies 
equally, so some threshold shifts may

[[Page 10010]]

not interfere with an animal's hearing of biologically relevant sounds. 
Their size and detectability makes it unlikely that these animals would 
be exposed to the higher energy or pressure expected to result in more 
severe effects.
    The predicted effects to delphinids are unlikely to cause long-term 
consequences for individual animals or populations. The GOA TMAA 
activities are not expected to occur in an area/time of specific 
importance for reproductive, feeding, or other known critical behaviors 
for delphinids. Stocks of delphinid species found in the Study Area are 
not depleted under the MMPA, nor are they listed under the ESA. 
Consequently, the activities are not expected to adversely impact rates 
of recruitment or survival of delphinid species.
    Porpoises--The Navy's acoustic analysis predicts that 16,244 
instances of Level B harassment (TTS and behavioral) of Dall's porpoise 
(Alaska stock) and 7,410 instances of Level B harassment of harbor 
porpoise (GOA and Southeast Alaska stocks) may occur each year from 
sonar and other active acoustic sources and explosives associated with 
training and testing activities in the Study Area. These represent a 
limited number of takes relative to population estimates for porpoise 
stocks in the Study Area (Table 6). When the numbers of takes for 
Dall's and harbor porpoise are compared to their respective estimated 
stock abundances and if one assumes that each take happens to a 
separate animal, less than 20 percent of the Alaska stock of Dall's 
porpoise, and less than 18 percent of the GOA and Southeast Alaska 
stocks of harbor porpoise would be harassed (behaviorally) during the 
course of a year. Because the estimates given above represent the total 
number of exposures and not necessarily the number of individuals 
exposed, it is more likely that fewer individuals would be taken, but a 
subset would be taken more than one time per year.
    Behavioral responses can range from a mild orienting response, or a 
shifting of attention, to flight and panic (Richardson, 1995; Nowacek, 
2007; Southall et al., 2007). Acoustic analysis (factoring in the post-
model correction for avoidance and mitigation) also predicted that 5 
Dall's porpoises might be exposed to sound levels from sonar and other 
active acoustic stressors and explosives likely to result in PTS or 
injury (Level A harassment).
    The number of Dall's and harbor porpoise behaviorally harassed by 
exposure to MFAS/HFAS in the Study Area is generally higher than the 
other species. This is due to the low Level B harassment threshold (we 
assume for the purpose of estimating take that all harbor porpoises 
exposed to 120 dB or higher MFAS/HFAS will be taken by Level B 
behavioral harassment), which essentially makes the ensonified area of 
effects significantly larger than for the other species. However, the 
fact that the threshold is a step function and not a curve (and 
assuming uniform density) means that the vast majority of the takes 
occur in the very lowest levels that exceed the threshold (it is 
estimated that approximately 80 percent of the takes are from exposures 
to 120 dB-126 dB), which means that anticipated behavioral effects are 
not expected to be severe (e.g., temporary avoidance). As mentioned 
above, an animal's exposure to a higher received level is more likely 
to result in a behavioral response that is more likely to adversely 
affect the health of an animal. Animals that do not exhibit a 
significant behavioral reaction would likely recover from any incurred 
costs, which reduces the likelihood of long-term consequences, such as 
reduced fitness, for the individual or population.
    Animals that experience hearing loss (TTS or PTS) may have reduced 
ability to detect relevant sounds such as predators, prey, or social 
vocalizations. Some porpoise vocalizations might overlap with the MFAS/
HFAS TTS frequency range (2-20 kHz). Recovery from a threshold shift 
(TTS; partial hearing loss) can take a few minutes to a few days, 
depending on the exposure duration, sound exposure level, and the 
magnitude of the initial shift, with larger threshold shifts and longer 
exposure durations requiring longer recovery times (Finneran et al., 
2005; Mooney et al., 2009a; Mooney et al., 2009b; Finneran and 
Schlundt, 2010). More severe shifts may not fully recover and thus 
would be considered PTS. However, large degrees of PTS are not 
anticipated for these activities because of the unlikelihood that 
animals will remain within the ensonified area (due to the short 
duration of the majority of exercises, the speed of the vessels, and 
the short distance within which the animal would need to approach the 
sound source) at high levels for the duration necessary to induce 
larger threshold shifts. Threshold shifts do not necessarily affect all 
hearing frequencies equally, so some threshold shifts may not interfere 
with an animal hearing biologically relevant sounds. The likely 
consequences to the health of an individual that incurs PTS can range 
from mild to more serious, depending upon the degree of PTS and the 
frequency band it is in, and many animals are able to compensate for 
the shift, although it may include energetic costs. Furthermore, likely 
avoidance of intense activity and sound coupled with mitigation 
measures would further reduce the potential for severe PTS exposures to 
occur. If a marine mammal is able to approach a surface vessel within 
the distance necessary to incur PTS, the likely speed of the vessel 
(nominal 10-15 knots) would make it very difficult for the animal to 
remain in range long enough to accumulate enough energy to result in 
more than a mild case of PTS.
    Harbor porpoises have been observed to be especially sensitive to 
human activity (Tyack et al., 2011; Pirotta et al., 2012). The 
information currently available regarding harbor porpoises suggests a 
very low threshold level of response for both captive (Kastelein et 
al., 2000; Kastelein et al., 2005) and wild (Johnston, 2002) animals. 
Southall et al. (2007) concluded that harbor porpoises are likely 
sensitive to a wide range of anthropogenic sounds at low received 
levels (~ 90 to 120 dB). Research and observations of harbor porpoises 
for other locations show that this small species is wary of human 
activity and will display profound avoidance behavior for anthropogenic 
sound sources in many situations at levels down to 120 dB re 1 
[micro]Pa (Southall, 2007). Harbor porpoises routinely avoid and swim 
away from large motorized vessels (Barlow et al., 1988; Evans et al., 
1994; Palka and Hammond, 2001; Polacheck and Thorpe, 1990). The 
vaquita, which is closely related to the harbor porpoise in the Study 
Area, appears to avoid large vessels at about 2,995 ft. (913 m) 
(Jaramillo-Legorreta et al., 1999). The assumption is that the harbor 
porpoise would respond similarly to large Navy vessels, possibly prior 
to commencement of sonar or explosive activity (i.e., pre-activity 
avoidance). Harbor porpoises may startle and temporarily leave the 
immediate area of the training or testing until after the event ends.
    ASW training exercises using MFAS/HFAS generally last for 2-16 
hours, and may have intervals of non-activity in between. In addition, 
the Navy does not typically conduct ASW exercises in the same 
locations. Given the average length of ASW exercises (times of 
continuous sonar use) and typical vessel speed, combined with the fact 
that the majority of porpoises in the Study Area would not likely 
remain in an area for successive days, it is unlikely that an animal 
would be exposed to MFAS/HFAS at levels likely to result in a 
substantive response (e.g., interruption

[[Page 10011]]

of feeding) that would then be carried on for more than one day or on 
successive days. Thompson et al. (2013) showed that seismic surveys 
conducted over a 10-day period in the North Sea did not result in the 
broad-scale displacement of harbor porpoises away from preferred 
habitat. The harbor porpoises were observed to leave the area at the 
onset of survey, but returned within a few hours, and the overall 
response of the porpoises decreased over the 10-day period.
    Considering the information above, the predicted effects to Dall's 
and harbor porpoise are unlikely to cause long-term consequences for 
individual animals or the population. The GOA activities are not 
expected to occur in an area/time of specific importance for 
reproductive, feeding, or other known critical behaviors for Dall's and 
harbor porpoise. Stocks of Dall's and harbor porpoise are not listed as 
depleted under the MMPA. Consequently, the activities are not expected 
to adversely impact annual rates of recruitment or survival of 
porpoises.
    Beaked Whales--Acoustic analysis predicts that 401 Baird's beaked 
whales (Alaska stock), 2,544 Cuvier's beaked whales (Alaska stock), and 
1,153 Stejneger's beaked whales (Alaska stock) will be taken annually 
by Level B harassment from exposure to sonar and other active acoustic 
stressors. These takes are anticipated to be in the form of behavioral 
harassment (mainly behavioral reaction and some TTS) and no injurious 
takes of beaked whales from sonar and other active acoustic stressors 
or explosives are requested or proposed. Relative to population size, 
training activities are anticipated to result only in a limited number 
of takes. Because the estimates given above represent the total number 
of exposures and not necessarily the number of individuals exposed, it 
is more likely that fewer individuals would be taken, but a subset 
would be taken more than one time per year. There are currently no 
reliable abundance estimates for Alaska stocks of Baird's, Cuvier's, 
and Stejner's beaked whales (Muto and Angliss, 2015).
    As is the case with harbor porpoises, beaked whales have been shown 
to be particularly sensitive to sound and therefore have been assigned 
a lower harassment threshold based on observations of wild animals by 
McCarthy et al. (2011) and Tyack et al. (2011). The fact that the Level 
B harassment threshold is a step function (The Navy has adopted an 
unweighted 140 dB re 1 [micro]Pa SPL threshold for significant 
behavioral effects for all beaked whales) and not a curve (and assuming 
uniform density) means that the vast majority of the takes occur in the 
very lowest levels that exceed the threshold (it is estimated that 
approximately 80 percent of the takes are from exposures to 140 dB to 
146 dB), which means that the anticipated effects for the majority of 
exposures are not expected to be severe (As mentioned above, an 
animal's exposure to a higher received level is more likely to result 
in a behavioral response that is more likely to adversely affect the 
health of an animal). Further, Moretti et al. (2014) recently derived 
an empirical risk function for Blainville's beaked whale that predicts 
there is a 0.5 probability of disturbance at a received level of 150 dB 
(CI: 144-155), suggesting that in some cases the current Navy step 
function may over-estimate the effects of an activity using sonar on 
beaked whales. Irrespective of the Moretti et al. (2014) risk function, 
NMFS' analysis assumes that all of the beaked whale Level B takes that 
are proposed for authorization will occur, and we base our negligible 
impact determination, in part, on the fact that these exposures would 
mainly occur at the very lowest end of the 140-dB behavioral harassment 
threshold where behavioral effects are expected to be much less severe 
and generally temporary in nature.
    Behavioral responses can range from a mild orienting response, or a 
shifting of attention, to flight and panic (Richardson, 1995; Nowacek, 
2007; Southall et al., 2007; Finneran and Jenkins, 2012). Research has 
also shown that beaked whales are especially sensitive to the presence 
of human activity (Tyack et al., 2011; Pirotta et al., 2012). Beaked 
whales have been documented to exhibit avoidance of human activity or 
respond to vessel presence (Pirotta et al., 2012). Beaked whales were 
observed to react negatively to survey vessels or low altitude aircraft 
by quick diving and other avoidance maneuvers, and none were observed 
to approach vessels (Wursig et al., 1998). Some beaked whale 
vocalizations may overlap with the MFAS/HFAS TTS frequency range (2-20 
kHz); however, as noted above, NMFS does not anticipate TTS of a 
serious degree or extended duration to occur as a result of exposure to 
MFA/HFAS. Recovery from a threshold shift (TTS) can take a few minutes 
to a few days, depending on the exposure duration, sound exposure 
level, and the magnitude of the initial shift, with larger threshold 
shifts and longer exposure durations requiring longer recovery times 
(Finneran et al., 2005; Mooney et al., 2009a; Mooney et al., 2009b; 
Finneran and Schlundt, 2010). Large threshold shifts are not 
anticipated for these activities because of the unlikelihood that 
animals will remain within the ensonified area (due to the short 
duration of the majority of exercises, the speed of the vessels, and 
the short distance within which the animal would need to approach the 
sound source) at high levels for the duration necessary to induce 
larger threshold shifts. Threshold shifts do not necessarily affect all 
hearing frequencies equally, so some threshold shifts may not interfere 
with an animal's hearing of biologically relevant sounds.
    It has been speculated for some time that beaked whales might have 
unusual sensitivities to sonar sound due to their likelihood of 
stranding in conjunction with MFAS use. Research and observations show 
that if beaked whales are exposed to sonar or other active acoustic 
sources they may startle, break off feeding dives, and avoid the area 
of the sound source to levels of 157 dB re 1 [micro]Pa, or below 
(McCarthy et al., 2011). Acoustic monitoring during actual sonar 
exercises revealed some beaked whales continuing to forage at levels up 
to 157 dB re 1 [micro]Pa (Tyack et al. 2011). Stimpert et al. (2014) 
tagged a Baird's beaked whale, which was subsequently exposed to 
simulated MFAS. Changes in the animal's dive behavior and locomotion 
were observed when received level reached 127 dB re 1[mu]Pa. However, 
Manzano-Roth et al. (2013) found that for beaked whale dives that 
continued to occur during MFAS activity, differences from normal dive 
profiles and click rates were not detected with estimated received 
levels up to 137 dB re 1 [micro]Pa while the animals were at depth 
during their dives. And in research done at the Navy's fixed tracking 
range in the Bahamas, animals were observed to leave the immediate area 
of the anti-submarine warfare training exercise (avoiding the sonar 
acoustic footprint at a distance where the received level was ``around 
140 dB'' SPL, according to Tyack et al. [2011]) but return within a few 
days after the event ended (Claridge and Durban, 2009; Moretti et al., 
2009, 2010; Tyack et al., 2010, 2011; McCarthy et al., 2011). Tyack et 
al. (2011) report that, in reaction to sonar playbacks, most beaked 
whales stopped echolocating, made long slow ascent to the surface, and 
moved away from the sound. A similar behavioral response study 
conducted in Southern California waters during the 2010-2011 field 
season found that Cuvier's beaked whales exposed to MFAS displayed 
behavior ranging from initial orientation changes

[[Page 10012]]

to avoidance responses characterized by energetic fluking and swimming 
away from the source (DeRuiter et al., 2013b). However, the authors did 
not detect similar responses to incidental exposure to distant naval 
sonar exercises at comparable received levels, indicating that context 
of the exposures (e.g., source proximity, controlled source ramp-up) 
may have been a significant factor. The study itself found the results 
inconclusive and meriting further investigation. Cuvier's beaked whale 
responses suggested particular sensitivity to sound exposure as 
consistent with results for Blainville's beaked whale.
    Populations of beaked whales and other odontocetes on the Bahamas 
and other Navy fixed ranges that have been operating for decades, 
appear to be stable. Behavioral reactions (avoidance of the area of 
Navy activity) seem likely in most cases if beaked whales are exposed 
to anti-submarine sonar within a few tens of kilometers, especially for 
prolonged periods (a few hours or more) since this is one of the most 
sensitive marine mammal groups to anthropogenic sound of any species or 
group studied to date and research indicates beaked whales will leave 
an area where anthropogenic sound is present (Tyack et al., 2011; De 
Ruiter et al., 2013; Manzano-Roth et al., 2013; Moretti et al., 2014). 
Research involving tagged Cuvier's beaked whales in the SOCAL Range 
Complex reported on by Falcone and Schorr (2012, 2014) indicates year-
round prolonged use of the Navy's training and testing area by these 
beaked whales and has documented movements in excess of hundreds of 
kilometers by some of those animals. Given that some of these animals 
may routinely move hundreds of kilometers as part of their normal 
pattern, leaving an area where sonar or other anthropogenic sound is 
present may have little, if any, cost to such an animal. Photo 
identification studies in the SOCAL Range Complex, a Navy range that is 
utilized for training and testing more frequently than the GOA TMAA 
Study Area, have identified approximately 100 individual Cuvier's 
beaked whale individuals with 40 percent having been seen in one or 
more prior years, with re-sightings up to 7 years apart (Falcone and 
Schorr, 2014). These results indicate long-term residency by 
individuals in an intensively used Navy training and testing area, 
which may also suggest a lack of long-term consequences as a result of 
exposure to Navy training and testing activities. Finally, results from 
passive acoustic monitoring estimated regional Cuvier's beaked whale 
densities were higher than indicated by the NMFS's broad scale visual 
surveys for the U.S. west coast (Hildebrand and McDonald, 2009).
    Based on the findings above, it is clear that the Navy's long-term 
ongoing use of sonar and other active acoustic sources has not 
precluded beaked whales from also continuing to inhabit those areas. In 
summary, based on the best available science, the Navy and NMFS believe 
that beaked whales that exhibit a significant TTS or behavioral 
reaction due to sonar and other active acoustic testing activities 
would generally not have long-term consequences for individuals or 
populations. Claridge (2013) speculated that sonar use in a Bahamas 
range could have ``a possible population-level effect'' on beaked 
whales based on lower abundance in comparison to control sites. In 
summary, Claridge suggested that lower reproductive rates observed at 
the Navy's Atlantic Undersea Test and Evaluation Center (AUTEC), when 
compared to a control site, were due to stressors associated with 
frequent and repeated use of Navy sonar. It is also important to note 
that there were some relevant shortcomings of this study. For example, 
all of the re-sighted whales during the 5-year study at both sites were 
female, which Claridge acknowledged can lead to a negative bias in the 
abundance estimation. There was also a reduced effort and shorter 
overall study period at the AUTEC site that failed to capture some of 
the emigration/immigration trends identified at the control site. 
Furthermore, Claridge assumed that the two sites were identical and 
therefore should have equal potential abundances; when in reality, 
there were notable physical differences. The author also acknowledged 
that ``information currently available cannot provide a quantitative 
answer to whether frequent sonar use at [the Bahamas range] is causing 
stress to resident beaked whales,'' and cautioned that the outcome of 
ongoing studies ``is a critical component to understanding if there are 
population-level effects.'' Moore and Barlow (2013) have noted a 
decline in beaked whale populations in a broad area of the Pacific 
Ocean area out to 300 nm from the coast and extending from the 
Canadian-U.S. border to the tip of Baja Mexico. There are scientific 
caveats and limitations to the data used for that analysis, as well as 
oceanographic and species assemblage changes on the U.S. Pacific coast 
not thoroughly addressed. Although Moore and Barlow (2013) have noted a 
decline in the overall beaked whale population along the Pacific coast, 
in the small fraction of that area where the Navy has been training and 
testing with sonar and other systems for decades (the Navy's SOCAL 
Range Complex), higher densities and long-term residency by individual 
Cuvier's beaked whales suggest that the decline noted elsewhere is not 
apparent where Navy sonar use is most intense. Navy sonar training and 
testing is not conducted along a large part of the U.S. west coast from 
which Moore and Barlow (2013) drew their survey data. In Southern 
California, based on a series of surveys from 2006 to 2008 and a high 
number encounter rate, Falcone et al. (2009) suggested the ocean basin 
west of San Clemente Island may be an important region for Cuvier's 
beaked whales given the number of animals encountered there. Follow-up 
research (Falcone and Schorr, 2012, 2014) in this same location 
suggests that Cuvier's beaked whales may have population sub-units with 
higher than expected residency, particularly in the Navy's instrumented 
Southern California Anti-Submarine Warfare Range. Encounters with 
multiple groups of Cuvier's and Baird's beaked whales indicated not 
only that they were prevalent on the range where Navy routinely trains 
and tests, but also that they were potentially present in much higher 
densities than had been reported for anywhere along the U.S. west coast 
(Falcone et al., 2009, Falcone and Schorr, 2012). This finding is also 
consistent with concurrent results from passive acoustic monitoring 
that estimated regional Cuvier's beaked whale densities were higher 
where Navy trains in the SOCAL training and testing area than indicated 
by NMFS's broad scale visual surveys for the U.S. west coast 
(Hildebrand and McDonald, 2009).
    NMFS also considered New et al. (2013) and their mathematical model 
simulating a functional link between foraging energetics and 
requirements for survival and reproduction for 21 species of beaked 
whales. However, NMFS concluded that New et al. (2013) model lacks 
critical data and accurate inputs necessary to form valid conclusions 
specifically about impacts of anthropogenic sound from Navy activities 
on beaked whale populations. The study itself notes the need for 
``future research,'' identifies ``key data needs'' relating to input 
parameters that ``particularly affected'' the model results, and states 
only that the use of the model ``in combination with more detailed 
research'' could help predict the effects of management actions on 
beaked whale species. In short,

[[Page 10013]]

information is not currently available to specifically support the use 
of this model in a project-specific evaluation of the effects of Navy 
activities on the impacted beaked whale species in GOA.
    No beaked whales are predicted in the acoustic analysis to be 
exposed to sound levels associated with PTS, other injury, or 
mortality. After decades of the Navy conducting similar activities in 
the GOA Study Area without incident, NMFS does not expect strandings, 
injury, or mortality of beaked whales to occur as a result of training 
activities. Stranding events coincident with Navy MFAS use in which 
exposure to sonar is believed to have been a contributing factor were 
detailed in the Stranding and Mortality section of this proposed rule. 
However, for some of these stranding events, a causal relationship 
between sonar exposure and the stranding could not be clearly 
established (Cox et al., 2006). In other instances, sonar was 
considered only one of several factors that, in their aggregate, may 
have contributed to the stranding event (Freitas, 2004; Cox et al., 
2006). Because of the association between tactical MFAS use and a small 
number of marine mammal strandings, the Navy and NMFS have been 
considering and addressing the potential for strandings in association 
with Navy activities for years. In addition to a suite of mitigation 
measures intended to more broadly minimize impacts to marine mammals, 
the reporting requirements set forth in this rule ensure that NMFS is 
notified immediately (or as soon as clearance procedures allow) if a 
stranded marine mammal is found during or shortly after, and in the 
vicinity of, any Navy training exercise utilizing MFAS, HFAS, or 
underwater explosive detonations (see General Notification of Injured 
or Dead Marine Mammals and the Stranding Response Plan in the 
regulatory text below). Additionally, through the MMPA process (which 
allows for adaptive management), NMFS and the Navy will determine the 
appropriate way to proceed in the event that a causal relationship were 
to be found between Navy activities and a future stranding.
    The GOA training activities are not expected to occur in an area/
time of specific importance for reproductive, feeding, or other known 
critical behaviors for beaked whales. None of the Pacific stocks for 
beaked whales species found in the Study Area are depleted under the 
MMPA. The degree of predicted Level B harassment is expected to be 
mild, and no beaked whales are predicted in the acoustic analysis to be 
exposed to sound levels associated with PTS, other injury, or 
mortality. Consequently, the activities are not expected to adversely 
impact annual rates of recruitment or survival of beaked whales.
    Pinnipeds--The Navy's acoustic analysis predicts that the following 
numbers of Level B harassment (TTS and behavioral reaction) may occur 
annually from sonar and other active acoustic stressors associated with 
training activities: 1,243 Steller sea lions (Eastern U.S. and Western 
U.S. stocks); 5 California sea lions (U.S. stock); 1,428 northern fur 
seals (Eastern Pacific stock); 245 northern elephant seals (California 
Breeding stock); and 4 harbor seals (North Kodiak, South Kodiak, and 
Prince William Sound stocks). These represent a limited number of takes 
relative to population estimates for pinniped stocks in the Study Area 
(Table 6). When the numbers of behavioral takes are compared to the 
estimated stock abundances, less than 2 percent of each of these stocks 
would be behaviorally harassed during the course of a year. These 
estimates represents the total number of exposures and not necessarily 
the number of individuals exposed, as a single individual may be 
exposed multiple times over the course of a year. Based on the 
distribution information presented in the LOA application, it is highly 
unlikely that ribbon seals would be encountered in the Study Area 
during events involving use of sonar and other active acoustic sources 
or explosives. The acoustic analysis did not predict any takes of 
ribbon seals and NMFS is not authorizing any takes of this species.
    Research has demonstrated that for pinnipeds, as for other mammals, 
recovery from a threshold shift (TTS) can take a few minutes to a few 
days, depending on the exposure duration, sound exposure level, and the 
magnitude of the initial shift, with larger threshold shifts and longer 
exposure durations requiring longer recovery times (Finneran et al., 
2005; Finneran and Schlundt, 2010; Mooney et al., 2009a; Mooney et al., 
2009b). However, large threshold shifts are not anticipated for these 
activities because of the unlikelihood that animals will remain within 
the ensonified area (due to the short duration of the majority of 
exercises, the speed of the vessels, and the short distance within 
which the animal would need to approach the sound source) at high 
levels for the duration necessary to induce larger threshold shifts. 
Threshold shifts do not necessarily affect all hearing frequencies 
equally, so threshold shifts may not necessarily interfere with an 
animal's ability to hear biologically relevant sounds.
    Research and observations show that pinnipeds in the water may be 
tolerant of anthropogenic noise and activity (a review of behavioral 
reactions by pinnipeds to impulsive and non-impulsive noise can be 
found in Richardson et al., 1995 and Southall et al., 2007). Available 
data, though limited, suggest that exposures between approximately 90 
and 140 dB SPL do not appear to induce strong behavioral responses in 
pinnipeds exposed to nonpulse sounds in water (Jacobs and Terhune, 
2002; Costa et al., 2003; Kastelein et al., 2006c). Based on the 
limited data on pinnipeds in the water exposed to multiple pulses 
(small explosives, impact pile driving, and seismic sources), exposures 
in the approximately 150 to 180 dB SPL range generally have limited 
potential to induce avoidance behavior in pinnipeds (Harris et al., 
2001; Blackwell et al., 2004; Miller et al., 2004). If pinnipeds are 
exposed to sonar or other active acoustic sources they may react in a 
number of ways depending on their experience with the sound source and 
what activity they are engaged in at the time of the acoustic exposure. 
Pinnipeds may not react at all until the sound source is approaching 
within a few hundred meters and then may alert, ignore the stimulus, 
change their behaviors, or avoid the immediate area by swimming away or 
diving. Houser et al. (2013) performed a controlled exposure study 
involving California sea lions exposed to a simulated MFAS signal. The 
purpose of this Navy-sponsored study was to determine the probability 
and magnitude of behavioral responses by California sea lions exposed 
to differing intensities of simulated MFAS signals. Behavioral 
reactions included increased respiration rates, prolonged submergence, 
and refusal to participate, among others. Younger animals were more 
likely to respond than older animals, while some sea lions did not 
respond consistently at any level. Houser et al.'s findings are 
consistent with current scientific studies and criteria development 
concerning marine mammal reactions to MFAS. Effects on pinnipeds in the 
Study Area that are taken by Level B harassment, on the basis of 
reports in the literature as well as Navy monitoring from past 
activities, will likely be limited to reactions such as increased 
swimming speeds, increased surfacing time, or decreased foraging (if 
such activity were occurring). Most likely, individuals will simply 
move away from the sound source and be temporarily displaced from those 
areas, or not respond at all. In areas of

[[Page 10014]]

repeated and frequent acoustic disturbance, some animals may habituate 
or learn to tolerate the new baseline or fluctuations in noise level. 
Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). While some animals may not return to an 
area, or may begin using an area differently due to training and 
testing activities, most animals are expected to return to their usual 
locations and behavior. Given their documented tolerance of 
anthropogenic sound (Richardson et al., 1995 and Southall et al., 
2007), repeated exposures of individuals (e.g., harbor seals) to levels 
of sound that may cause Level B harassment are unlikely to result in 
hearing impairment or to significantly disrupt foraging behavior. As 
stated above, pinnipeds may habituate to or become tolerant of repeated 
exposures over time, learning to ignore a stimulus that in the past has 
not accompanied any overt threat.
    Thus, even repeated Level B harassment of some small subset of an 
overall stock is unlikely to result in any significant realized 
decrease in fitness to those individuals, and would not result in any 
adverse impact to the stock as a whole. Evidence from areas where the 
Navy extensively trains and tests provides some indication of the 
possible consequences resulting from those proposed activities. In the 
confined waters of Washington State's Hood Canal where the Navy has 
been training and intensively testing for decades and harbor seals are 
present year-round, the population level has remained stable suggesting 
the area's carrying capacity likely has been reached (Jeffries et al., 
2003; Gaydos et al., 2013). Within Puget Sound there are several 
locations where pinnipeds use Navy structures (e.g., submarines, 
security barriers) for haulouts. Given that animals continue to choose 
these areas for their resting behavior, it would appear there are no 
long-term effects or consequences to those animals as a result of 
ongoing and routine Navy activities.
    Generally speaking, most pinniped stocks in the Study Area are 
thought to be stable or increasing (Carretta et al., 2014, 2015). 
Abundance estimates for pinniped stocks in the Study Area are shown in 
Table 6. Relative to population size, training activities are 
anticipated to result only in a limited number of takes. No areas of 
specific importance for reproduction or feeding for pinnipeds have been 
identified in the Study Area. Consequently, the activities are not 
expected to adversely impact rates of recruitment or survival of 
pinniped species.
    Western U.S. stocks of Steller sea lions are listed as endangered 
under the ESA; however, there is no designated critical habitat Steller 
sea lions in the Study Area. As a conservative measure, the GOA TMAA 
boundary zone was specifically drawn to exclude any nearby critical 
habitat and associated terrestrial, air, or aquatic zones. NMFS is 
currently engaged in an internal Section 7 consultation under the ESA 
and the outcome of that consultation will further inform our final 
determination.

Long-Term Consequences

    The best assessment of long-term consequences from training 
activities will be to monitor the populations over time within a given 
Navy range complex. A U.S. workshop on Marine Mammals and Sound (Fitch 
et al., 2011) indicated a critical need for baseline biological data on 
marine mammal abundance, distribution, habitat, and behavior over 
sufficient time and space to evaluate impacts from human-generated 
activities on long-term population survival. The Navy has developed 
monitoring plans for protected marine mammals occurring on Navy ranges 
with the goal of assessing the impacts of training and testing 
activities on marine species and the effectiveness of the Navy's 
current mitigation practices. Continued monitoring efforts over time 
will be necessary to completely evaluate the long-term consequences of 
exposure to noise sources.
    Since 2006 across all Navy range complexes (in the Atlantic, Gulf 
of Mexico, and the Pacific), there have been more than 80 reports, 
including Major Exercise Reports, Annual Exercise Reports, and 
Monitoring Reports. For the Pacific since 2011, there have been 29 
monitoring and exercise reports submitted to NMFS to further research 
goals aimed at understanding the Navy's impact on the environment as it 
carries out its mission to train and test.
    In addition to this multi-year record of reports from across the 
Navy, there have also been ongoing Behavioral Response Study research 
efforts (in Southern California and the Bahamas) specifically focused 
on determining the potential effects from Navy mid-frequency sonar 
(Southall et al., 2011, 2012; McCarthy et al., 2011; Tyack et al., 
2011; DeRuiter et al., 2013b; Goldbogen et al., 2013; Moretti et al., 
2014). This multi-year compendium of monitoring, observation, study, 
and broad scientific research is informative with regard to assessing 
the effects of Navy training and testing in general. Given that this 
record involves many of the same Navy training activities being 
considered for the Study Area and because it includes all the marine 
mammal taxonomic families and many of the same species, this compendium 
of Navy reporting is directly applicable to assessing locations such as 
the GOA TMAA.
    In the Hawaii and Southern California Navy training and testing 
ranges from 2009 to 2012, Navy-funded marine mammal monitoring research 
completed over 5,000 hours of visual survey effort covering over 65,000 
nautical miles, sighted over 256,000 individual marine mammals, took 
over 45,600 digital photos and 36 hours of digital video, attached 70 
satellite tracking tags to individual marine mammals, and collected 
over 40,000 hours of passive acoustic recordings. In Hawaii alone 
between 2006 and 2012, there were 21 scientific marine mammal surveys 
conducted before, during, or after major exercises. This monitoring 
effort is consistent with other research from these areas in that there 
have been no direct evidence demonstration that routine Navy training 
and testing has negatively impacted marine mammal populations 
inhabiting these Navy ranges. Continued monitoring efforts over time 
will be necessary to completely evaluate the long-term consequences of 
exposure to noise sources. Other research findings related to the 
general topic of long-term impacts are discussed above in the Species-
Specific Analysis.
    Based on monitoring conducted before, during, and after Navy 
training and testing events since 2006, the NMFS' assessment is that it 
is unlikely there will be impacts having any long-term consequences to 
populations of marine mammals as a result of the proposed continuation 
of training and testing in the ocean areas historically used by the 
Navy including the Study Area. This assessment of likelihood is based 
on four indicators from areas in the Pacific where Navy training and 
testing has been ongoing for decades: (1) Evidence suggesting or 
documenting increases in the numbers of marine mammals present 
(Calambokidis and Barlow, 2004; Falcone et al., 2009; Hildebrand and 
McDonald, 2009; Falcone and Shorr, 2012; Calambokidis et al., 2009a; 
Berman-Kowalewski et al., 2010; Moore and Barlow, 2011; Barlow et al., 
2011; Kerosky et al,. 2012; Smultea et al., 2013; [Scaron]irovi[cacute] 
et al., 2015), (2) examples of documented presence and site fidelity of 
species and long-term residence by individual animals of some species 
(Hooker et al.,

[[Page 10015]]

2002; McSweeney et al., 2007; McSweeney et al., 2010; Martin and Kok, 
2011; Baumann-Pickering et al., 2012; Falcone and Schorr, 2014), (3) 
use of training and testing areas for breeding and nursing activities 
(Littnan, 2010), and (4) 6 years of comprehensive monitoring data 
indicating a lack of any observable effects to marine mammal 
populations as a result of Navy training and testing activities.
    To summarize, while the evidence covers most marine mammal 
taxonomic suborders, it is limited to a few species and only suggestive 
of the general viability of those species in intensively used Navy 
training and testing areas (Barlow et al., 2011; Calambokidis et al., 
2009b; Falcone et al., 2009; Littnan, 2011; Martin and Kok, 2011; 
McCarthy et al., 2011; McSweeney et al., 2007; McSweeney et al., 2009; 
Moore and Barlow, 2011; Tyack et al., 2011; Southall et al., 2012a; 
Melcon, 2012; Goldbogen, 2013; Baird et al., 2013). However, there is 
no direct evidence that routine Navy training and testing spanning 
decades has negatively impacted marine mammal populations at any Navy 
Range Complex. Although there have been a few strandings associated 
with use of sonar in other locations (see U.S. Department of the Navy, 
2013b), Ketten (2012) has recently summarized, ``to date, there has 
been no demonstrable evidence of acute, traumatic, disruptive, or 
profound auditory damage in any marine mammal as the result of 
anthropogenic noise exposures, including sonar.'' Therefore, based on 
the best available science (Barlow et al., 2011; Carretta et al., 2011; 
Falcone et al., 2009; Falcone and Schorr, 2012, 2014; Jeffries et al., 
2003; Littnan, 2011; Martin and Kok, 2011; McCarthy et al., 2011; 
McSweeney et al., 2007; McSweeney et al., 2009; Moore and Barlow, 2011; 
Tyack et al., 2011; Southall et al., 2012, 2013, 2014; Manzano-Roth et 
al., 2013; DeRuiter et al., 2013b; Goldbogen et al., 2013; Moretti et 
al., 2014; Smultea and Jefferson, 2014; [Scaron]irovi[cacute] et al. 
2015), including data developed in the series of 80+ reports submitted 
to NMFS, we believe that long-term consequences for individuals or 
populations are unlikely to result from Navy training activities in the 
Study Area.

Preliminary Determination

    Training activities proposed in the GOA TMAA Study Area would 
result in mainly Level B and some Level A takes, as summarized in 
Tables 12 and 13. Based on best available science, NMFS concludes that 
exposures to marine mammal species and stocks due to GOA TMAA 
activities would result in individuals experiencing primarily short-
term (temporary and short in duration) and relatively infrequent 
effects of the type or severity not expected to be additive. In 
addition, only a generally small portion of the stocks and species is 
likely to be exposed.
    Marine mammal takes from Navy activities are not expected to impact 
annual rates of recruitment or survival and will therefore not result 
in population-level impacts for the following reasons:
     Most acoustic exposures (greater than 99 percent) would be 
within the non-injurious TTS or behavioral effects zones (Level B 
harassment consisting of generally temporary modifications in behavior) 
and none of the estimated exposures would result in mortality.
     As mentioned earlier, an animal's exposure to a higher 
received level is more likely to result in a behavioral response that 
is more likely to adversely affect the health of the animal. For low 
frequency cetaceans (mysticetes) in the Study Area, most Level B 
exposures will occur at received levels less than 156 dB. The majority 
of estimated odontocete takes from MFAS/HFAS (at least for hull-mounted 
sonar, which is responsible for most of the sonar-related takes) also 
result from exposures to received levels less than 156 dB. Therefore, 
the majority of Level B takes are expected to be in the form of milder 
responses (i.e., lower-level exposures that still rise to the level of 
a take, but would likely be in the less severe range of responses that 
qualify as a take), and are not expected to have deleterious impacts on 
the fitness of any individuals. Marine mammal densities inputted into 
the acoustic effects model are also conservative, particularly when 
considering species for which data in portions of the Study Area is 
limited, and when considering the seasonal migrations that extend 
throughout the Study Area.
     Acoustic disturbances caused by Navy sonar and explosives 
are short-term, intermittent, and (in the case of sonar) transitory. 
Even when an animal's exposure to active sonar may be more than one 
time, the intermittent nature of the sonar signal, the signal's low 
duty cycle (MFAS has a typical ping of every 50 seconds), and the fact 
that both the vessel and animal are moving, provide a very small chance 
that exposure to active sonar for individual animals and stocks would 
be repeated over extended periods of time. Consequently, we would not 
expect the Navy's activities to create conditions of long-term, 
continuous underwater noise leading to habitat abandonment or long-term 
hormonal or physiological stress responses in marine mammals.
     Range complexes where intensive training and testing have 
been occurring for decades have populations of multiple species with 
strong site fidelity (including highly sensitive resident beaked whales 
at some locations) and increases in the number of some species. 
Populations of beaked whales and other odontocetes in the Bahamas, and 
in other Navy fixed ranges that have been operating for tens of years, 
appear to be stable.
     Navy monitoring of Navy-wide activities since 2006 has 
documented hundreds of thousands of marine mammals on the range 
complexes and there are only two instances of overt behavioral change 
that have been observed.
     Navy monitoring of Navy-wide activities since 2006 has 
documented no demonstrable instances of injury to marine mammals as a 
result of non-impulsive acoustic sources.
     In at least three decades of similar Navy activities, only 
one instance of injury to marine mammals (March 25, 2011; three long-
beaked common dolphin off Southern California) has occurred as a known 
result of training or testing using an impulsive source (underwater 
explosion). Of note, the time-delay firing underwater explosive 
training activity implicated in the March 4 incident is not proposed 
for the training activities in the GOA Study Area.
     The protective measures described in the Proposed 
Mitigation section above are designed to reduce vessel strike potential 
and avoid sound exposures that may cause serious injury, and to result 
in the least practicable adverse effect on marine mammal species or 
stocks.
    Based on this analysis of the likely effects of the specified 
activity on marine mammals and their habitat, which includes 
consideration of the materials provided in the Navy's LOA application 
and GOA DSEIS/OEIS, and dependent upon the implementation of the 
mitigation and monitoring measures, NMFS finds that the total marine 
mammal take from the Navy's training and testing activities in the GOA 
Study Area will have a negligible impact on the affected marine mammal 
species or stocks. NMFS proposes to issue regulations for these 
activities in order to prescribe the means of effecting the least 
practicable adverse impact on marine mammal species or stocks and their 
habitat, and to set forth requirements pertaining to the monitoring and 
reporting of that taking.

[[Page 10016]]

Subsistence Harvest of Marine Mammals

    There are no relevant subsistence uses of marine mammals implicated 
by this action. None of the proposed training activities in the Study 
Area occur where traditional Arctic subsistence hunting exists. 
Therefore, NMFS has preliminarily determined that the total taking 
affecting species or stocks would not have an unmitigable adverse 
impact on the availability of such species or stocks for taking for 
subsistence purposes.

ESA

    There are eight marine mammal species under NMFS jurisdiction that 
are listed as endangered or threatened under the ESA with confirmed or 
possible occurrence in the Study Area: Blue whale, fin whale, humpback 
whale, sei whale, sperm whale, gray whale (Western North Pacific 
stock), North Pacific right whale, and Steller sea lion (Western U.S. 
stock). The Navy will consult with NMFS pursuant to section 7 of the 
ESA, and NMFS will also consult internally on the issuance of a LOA 
under section 101(a)(5)(A) of the MMPA for GOA TMAA activities. 
Consultation will be concluded prior to a determination on the issuance 
of the final rule and a LOA.

NEPA

    NMFS is a cooperating agency on the Navy's GOA DSEIS/OEIS, which 
was prepared and released to the public August 23, 2014. Upon 
completion, the GOA Final SEIS/OEIS will be made available for public 
review and posted on NMFS' Web site: http://www.nmfs.noaa.gov/pr/permits/incidental/military.htm. NMFS intends to adopt the GOA Final 
SEIS/OEIS, if adequate and appropriate. Currently, we believe that the 
adoption of the GOA Final SEIS/OEIS will allow NMFS to meet its 
responsibilities under NEPA for the issuance of regulations and LOA for 
GOA TMAA. If the GOA SEIS/OEIS is deemed inadequate by NMFS, NMFS would 
supplement the existing analysis to ensure that we comply with NEPA 
prior to issuing the final rule and LOA.

Classification

    The Office of Management and Budget has determined that this 
proposed rule is not significant for purposes of Executive Order 12866.
    Pursuant to the Regulatory Flexibility Act (RFA), the Chief Counsel 
for Regulation of the Department of Commerce has certified to the Chief 
Counsel for Advocacy of the Small Business Administration that this 
proposed rule, if adopted, would not have a significant economic impact 
on a substantial number of small entities. The RFA requires federal 
agencies to prepare an analysis of a rule's impact on small entities 
whenever the agency is required to publish a notice of proposed 
rulemaking. However, a federal agency may certify, pursuant to 5 U.S.C. 
605 (b), that the action will not have a significant economic impact on 
a substantial number of small entities. The Navy is the sole entity 
that would be affected by this rulemaking, and the Navy is not a small 
governmental jurisdiction, small organization, or small business, as 
defined by the RFA. Any requirements imposed by an LOA issued pursuant 
to these regulations, and any monitoring or reporting requirements 
imposed by these regulations, would be applicable only to the Navy. 
NMFS does not expect the issuance of these regulations or the 
associated LOA to result in any impacts to small entities pursuant to 
the RFA. Because this action, if adopted, would directly affect the 
Navy and not a small entity, NMFS concludes the action would not result 
in a significant economic impact on a substantial number of small 
entities.

List of Subjects in 50 CFR Part 218

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

    Dated: February 17, 2016.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine 
Fisheries Service.

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

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

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

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

Subpart N--[Removed and Reserved]

0
3. Remove and reserve subpart N, consisting of Sec. Sec.  218.120 
through 218.129.
0
4. Subpart P is added to part 218 to read as follows:
Subpart P--Taking and Importing Marine Mammals; U.S. Navy's Gulf of 
Alaska Temporary Maritime Activities Area (GOA TMAA) Study Area
Sec.
218.150 Specified activity and specified geographical region.
218.151 Effective dates.
218.152 Permissible methods of taking.
218.153 Prohibitions.
218.154 Mitigation.
218.155 Requirements for monitoring and reporting.
218.156 Applications for letters of authorization.
218.157 Letters of authorization.
218.158 Renewal and modifications of letters of authorization and 
adaptive management.

Subpart P--Taking and Importing Marine Mammals; U.S. Navy's Gulf of 
Alaska Temporary Maritime Activities Area (GOA TMAA) Study Area


Sec.  218.150  Specified activity and specified geographical region.

    (a) Regulations in this subpart apply only to the U.S. Navy for the 
taking of marine mammals that occurs in the area outlined in paragraph 
(b) of this section and that occurs incidental to the activities 
described in paragraph (c) of this section.
    (b) The taking of marine mammals by the Navy is only authorized if 
it occurs within the GOA TMAA Study Area, which is bounded by a hexagon 
with the following six corners: 57[deg]30'[deg] N. lat., 
141[deg]30'[deg] W. long.; 59[deg]36'[deg] N. lat., 148[deg]10'[deg] W. 
long.; 58[deg]57'[deg] N. lat., 150[deg]04'[deg] W. long.; 
58[deg]20'[deg] N. lat., 151[deg]00'[deg] W. long.; 57[deg]16'[deg] N. 
lat., 151[deg]00'[deg] W. long.; and 55[deg]30'[deg] N. lat., 
142[deg]00'[deg] W. long.
    (c) The taking of marine mammals by the Navy is only authorized if 
it occurs incidental to the following activities:
    (1) Sonar and other Active Sources Used During Training:
    (i) Mid-frequency (MF) Source Classes:
    (A) MF1--an average of 541 hours per year.
    (B) MF3--an average of 48 hours per year.
    (C) MF4--an average of 53 hours per year.
    (D) MF5--an average of 25 items per year.
    (E) MF6--an average of 21 items per year.
    (F) MF11--an average of 78 hours per year.
    (ii) High-frequency (HF) Source Classes:
    (A) HF1--an average of 24 hours per year.
    (B) HF6--an average of 80 items per year.
    (iii) Anti-Submarine Warfare (ASW) Source Classes:
    (A) ASW2--an average of 80 hours per year.
    (B) ASW3--an average of 546 hours per year.
    (C) ASW4--an average 4 items per year.

[[Page 10017]]

    (iv) Torpedoes (TORP):
    (A) TORP2--an average of 5 items per year.
    (B) [Reserved]
    (2) Impulsive Source Detonations During Training:
    (i) Explosive Classes:
    (A) E5 (>5 to 10 pound [lb] net explosive weight (NEW))--an average 
of 112 detonations per year.
    (B) E6 (>10 to 20 lb NEW)--an average of 2 detonations per year.
    (C) E7 (>20 to 60 lb NEW)--an average of 4 detonations per year.
    (D) E8 (>60 to 100 lb NEW)--an average of 6 detonations per year.
    (E) E9 (>100 to 250 lb NEW)--an average of 142 detonations per 
year.
    (F) E10 (>250 to 500 lb NEW)--an average of 32 detonations per 
year.
    (G) E11 (>500 to 650 lb NEW)--an average of 2 detonations per year.
    (H) E12 (>650 to 1,000 lb NEW)--an average of 4 detonations per 
year.
    (ii) [Reserved]


Sec.  218.151  Effective dates.

    Regulations in this subpart are effective May 4, 2016, through May 
3, 2021.


Sec.  218.152  Permissible methods of taking.

    (a) Under letter of authorization (LOA) issued pursuant to 
Sec. Sec.  216.106 and 218.157 of this chapter, the holder of the LOA 
may incidentally, but not intentionally, take marine mammals within the 
area described in Sec.  218.150, provided the activity is in compliance 
with all terms, conditions, and requirements of these regulations and 
the LOA.
    (b) The activities identified in Sec.  218.150(c) must be conducted 
in a manner that minimizes, to the greatest extent practicable, any 
adverse impacts on marine mammals and their habitat.
    (c) The incidental take of marine mammals under the activities 
identified in Sec.  218.150(c) is limited to the following species, by 
the identified method of take and the indicated number of times:
    (1) Level B Harassment for all Training Activities:
    (i) Mysticetes:
    (A) Blue whale (Balaenoptera musculus), Eastern North Pacific--475 
(an average of 95 per year).
    (B) Fin whale (Balaenoptera physalus), Northeast Pacific--12,910 
(an average of 2,582 per year).
    (C) Humpback whale (Megaptera novaeangliae), Central North 
Pacific--645 (an average of 129 per year).
    (D) Humpback whale (Megaptera novaeangliae), Western North 
Pacific--50 (an average of 10 per year).
    (E) Minke whale (Balaenoptera acutorostrata), Alaska--435 (an 
average of 87 per year).
    (F) North Pacific right whale (Eubalaena japonica), Eastern North 
Pacific--35 (an average of 7 per year).
    (G) Sei whale (Balaenoptera borealis), Eastern North Pacific--65 
(an average of 13 per year).
    (ii) Odontocetes:
    (A) Baird's beaked whale (Berardius bairdii), Alaska--2,005 (an 
average of 401 per year).
    (B) Cuvier's beaked whale (Ziphius cavirostris), Alaska--12,720 (an 
average of 2,544 per year).
    (C) Dall's porpoise (Phocoenoidea dalli), Alaska--81,220 (an 
average of 16,244 per year).
    (D) Harbor porpoise (Phocoena phocoena), GOA--27,420 (an average of 
5,484 per year).
    (E) Harbor porpoise (Phocoena phocoena), Southeast Alaska--9,630 
(an average of 1,926 per year).
    (F) Killer whale (Orcinus orca), Alaska Resident--2,820 (an average 
of 564 per year).
    (G) Killer whale (Orcinus orca), Eastern North Pacific Offshore--
265 (an average of 53 per year).
    (H) Killer whale (Orcinus orca), AT1 Transient--5 (an average of 1 
per year).
    (I) Killer whale (Orcinus orca), GOA, Aleutian Island, and Bearing 
Sea Transient--720 (an average of 144 per year).
    (J) Pacific white-sided dolphin (Lagenorhynchus obliquidens), North 
Pacific--9,815 (an average of 1,963 per year).
    (K) Stejneger's beaked whale (Mesoplodon stejnegeri), Alaska--5,765 
(an average of 1,153 per year).
    (L) Sperm whale (Physeter macrocephalus), North Pacific--985 (an 
average of 197 per year).
    (iii) Pinnipeds:
    (A) California sea lion (Zalophus californianus), U.S.--25 (an 
average of 5 per year).
    (B) Steller sea lion (Eumetopias jubatus), Eastern U.S.--3,355 (an 
average of 671 per year).
    (C) Steller sea lion (Eumetopias jubatus), Western U.S.--2,860 (an 
average of 572 per year).
    (D) Harbor seal (Phoca vitulina), North Kodiak--5 (an average of 1 
per year).
    (E) Harbor seal (Phoca vitulina), South Kodiak--5 (an average of 1 
per year).
    (F) Harbor seal (Phoca vitulina), Prince William Sound--10 (an 
average of 2 per year).
    (G) Northern elephant seal (Mirounga angustirostris), California 
Breeding--1,225 (an average of 245 per year).
    (H) Northern fur seal (Callorhinus ursinus), Eastern Pacific--7,140 
(an average of 1,428 per year).
    (2) Level A Harassment for all Training Activities:
    (i) Odontocetes:
    (A) Dall's porpoise (Phocoenoidea dalli), Alaska--25 (an average of 
5 per year).
    (B) [Reserved]
    (ii) [Reserved]


Sec.  218.153  Prohibitions.

    Notwithstanding takings contemplated in Sec.  218.152 and 
authorized by an LOA issued under Sec. Sec.  216.106 and 218.157 of 
this chapter, no person in connection with the activities described in 
Sec.  218.150 may:
    (a) Take any marine mammal not specified in Sec.  218.152(c);
    (b) Take any marine mammal specified in Sec.  218.152(c) other than 
by incidental take as specified in Sec.  218.152(c);
    (c) Take a marine mammal specified in Sec.  218.152(c) if such 
taking results in more than a negligible impact on the species or 
stocks of such marine mammal; or
    (d) Violate, or fail to comply with, the terms, conditions, and 
requirements of these regulations or an LOA issued under Sec. Sec.  
216.106 and 218.157 of this chapter.


Sec.  218.154  Mitigation.

    (a) When conducting training activities, as identified in Sec.  
218.150, the mitigation measures contained in the LOA issued under 
Sec. Sec.  216.106 and 218.157 of this chapter must be implemented. 
These mitigation measures include, but are not limited to:
    (1) Lookouts.The Navy shall have two types of lookouts for the 
purposes of conducting visual observations: Those positioned on ships; 
and those positioned ashore, in aircraft, or on boats. The following 
are protective measures concerning the use of lookouts.
    (i) Lookouts positioned on surface ships shall be dedicated solely 
to diligent observation of the air and surface of the water. Their 
observation objectives shall include, but are not limited to, detecting 
the presence of biological resources and recreational or fishing boats, 
observing mitigation zones, and monitoring for vessel and personnel 
safety concerns.
    (ii) Due to manning and space restrictions on aircraft, small 
boats, and some Navy ships, lookouts for these platforms may be 
supplemented by the aircraft crew or pilot, boat crew, range site 
personnel, or shore-side personnel. Lookouts positioned in minimally

[[Page 10018]]

manned platforms may be responsible for tasks in addition to observing 
the air or surface of the water (e.g., navigation of a helicopter or 
small boat). However, all lookouts shall, considering personnel safety, 
practicality of implementation, and impact on the effectiveness of the 
activity, comply with the observation objectives described above for 
lookouts positioned on ships.
    (iii) All personnel standing watch on the bridge, Commanding 
Officers, Executive Officers, maritime patrol aircraft aircrews, anti-
submarine warfare helicopter crews, civilian equivalents, and lookouts 
shall successfully complete the United States Navy Marine Species 
Awareness Training prior to standing watch or serving as a lookout.
    (iv) Lookout measures for non-impulsive sound:
    (A) With the exception of vessels less than 65 ft (20 m) in length, 
ships using hull-mounted mid-frequency active sonar sources associated 
with anti-submarine warfare activities at sea shall have two Lookouts 
at the forward position of the vessel.
    (B) While using hull-mounted mid-frequency active sonar sources 
associated with anti-submarine warfare activities at sea, vessels less 
than 65 ft (20 m) in length shall have one lookout at the forward 
position of the vessel due to space and manning restrictions.
    (C) During non-hull mounted mid-frequency active sonar training 
activities, Navy aircraft participating in exercises at sea shall 
conduct and maintain, when operationally feasible and safe, 
surveillance for marine species of concern as long as it does not 
violate safety constraints or interfere with the accomplishment of 
primary operational duties. Helicopters shall observe/survey the 
vicinity of an anti-submarine warfare training event for 10 minutes 
before the first deployment of active (dipping) sonar in the water.
    (D) Ships or aircraft conducting non-hull-mounted mid-frequency 
active sonar, such as helicopter dipping sonar systems, shall maintain 
one lookout.
    (E) Ships conducting high-frequency active sonar shall maintain one 
lookout.
    (v) Lookout measures for explosives and impulsive sound:
    (A) Aircraft conducting explosive signal underwater sound buoy 
activities using >0.5-2.5 lb. NEW shall have one lookout.
    (B) Surface vessels or aircraft conducting small-, medium-, or 
large-caliber gunnery exercises against a surface target shall have one 
lookout. From the intended firing position, trained lookouts shall 
survey the mitigation zone for marine mammals prior to commencement and 
during the exercise as long as practicable. Towing vessels, if 
applicable, shall also maintain one lookout. If a marine mammal is 
sighted in the vicinity of the exercise, the tow vessel shall 
immediately notify the firing vessel in order to secure gunnery firing 
until the area is clear.
    (C) Aircraft conducting explosive bombing exercises shall have one 
lookout and any surface vessels involved shall have trained Lookouts. 
If surface vessels are involved, lookouts shall survey for floating 
kelp and marine mammals. Aircraft shall visually survey the target and 
buffer zone for marine mammals prior to and during the exercise. The 
survey of the impact area shall be made by flying at 1,500 ft. (460 m) 
or lower, if safe to do so, and at the slowest safe speed. Release of 
ordnance through cloud cover is prohibited: Aircraft must be able to 
actually see ordnance impact areas. Survey aircraft should employ most 
effective search tactics and capabilities.
    (D) When aircraft are conducting missile exercises against a 
surface target, the Navy shall have one Lookout positioned in an 
aircraft. Aircraft shall visually survey the target area for marine 
mammals. Visual inspection of the target area shall be made by flying 
at 1,500 ft. (457 m) or lower, if safe to do so, and at slowest safe 
speed. Firing or range clearance aircraft must be able to actually see 
ordnance impact areas.
    (E) Ships conducting explosive and non-explosive gunnery exercises 
shall have one Lookout on the ship. This may be the same lookout 
described in paragraph (B) above for surface vessels conducting small-, 
medium-, or large-caliber gunnery exercises when that activity is 
conducted from a ship against a surface target.
    (F) During sinking exercises, two Lookouts shall be used. One 
lookout shall be positioned in an aircraft and one lookout shall be 
positioned on a vessel.
    (vi) Lookout measures for physical strike and disturbance:
    (A) While underway, surface ships shall have at least one lookout.
    (B) [Reserved]
    (vii) Lookout measures for non-explosive practice munitions:
    (A) Gunnery exercises using non-explosive practice munitions (e.g., 
small-, medium-, and large-caliber) using a surface target shall have 
one lookout.
    (B) During non-explosive bombing exercises one lookout shall be 
positioned in an aircraft and trained lookouts shall be positioned in 
any surface vessels involved.
    (C) When aircraft are conducting non-explosive missile exercises 
(including exercises using rockets) against a surface target, the Navy 
shall have one lookout positioned in an aircraft.
    (2) Mitigation Zones--The following are protective measures 
concerning the implementation of mitigation zones.
    (i) Mitigation zones shall be measured as the radius from a source 
and represent a distance to be monitored.
    (ii) Visual detections of marine mammals or sea turtles within a 
mitigation zone shall be communicated immediately to a watch station 
for information dissemination and appropriate action.
    (iii) Mitigation zones for non-impulsive sound:
    (A) The Navy shall ensure that hull-mounted mid-frequency active 
sonar transmission levels are limited to at least 6 dB below normal 
operating levels if any detected marine mammals or sea turtles are 
within 1,000 yd. (914 m) of the sonar dome (the bow).
    (B) The Navy shall ensure that hull-mounted mid-frequency active 
sonar transmissions are limited to at least 10 dB below the equipment's 
normal operating level if any detected marine mammals or sea turtles 
are within 500 yd. (457 m) of the sonar dome.
    (C) The Navy shall ensure that hull-mounted mid-frequency active 
sonar transmissions are ceased if any detected cetaceans or sea turtles 
are within 200 yd. (183 m) and pinnipeds are within 100 yd. (90 m) of 
the sonar dome. Transmissions shall not resume until the marine mammal 
has been observed exiting the mitigation zone, is thought to have 
exited the mitigation zone based on its course and speed, has not been 
detected for 30 minutes, the vessel has transited more than 2,000 yd. 
beyond the location of the last detection, or the ship concludes that 
dolphins are deliberately closing in on the ship to ride the ship's bow 
wave (and there are no other marine mammal sightings within the 
mitigation zone). Active transmission may resume when dolphins are bow 
riding because they are out of the main transmission axis of the active 
sonar while in the shallow-wave area of the ship bow.
    (D) The Navy shall ensure that high-frequency and non-hull-mounted 
mid-frequency active sonar transmission levels are ceased if any 
detected cetaceans are within 200 yd. (180 m) and pinnipeds are within 
100 yd. (90 m) of the source. Transmissions shall not resume until the 
marine mammal has been observed exiting the mitigation zone, is thought 
to have exited the mitigation zone based on its course and speed, the 
mitigation zone has been

[[Page 10019]]

clear from any additional sightings for a period of 10 minutes for an 
aircraft-deployed source, the mitigation zone has been clear from any 
additional sightings for a period of 30 minutes for a vessel-deployed 
source, the vessel or aircraft has repositioned itself more than 400 
yd. (370 m) away from the location of the last sighting, or the vessel 
concludes that dolphins are deliberately closing in to ride the 
vessel's bow wave (and there are no other marine mammal sightings 
within the mitigation zone).
    (iv) Mitigation zones for explosive and impulsive sound:
    (A) A mitigation zone with a radius of 350 yd. (320 m) shall be 
established for explosive signal underwater sonobuoys using >0.5 to 2.5 
lb NEW. Explosive signal underwater sonobuoys shall not be deployed if 
concentrations of floating vegetation (kelp paddies) are observed in 
the mitigation zone (around the intended deployment location). 
Explosive signal underwater sonobuoy deployment shall cease if a marine 
mammal is sighted within the mitigation zone. Detonations shall 
recommence if any one of the following conditions is met: The animal is 
observed exiting the mitigation zone, the animal is thought to have 
exited the mitigation zone based on its course and speed, or the 
mitigation zone has been clear from any additional sightings for a 
period of 10 minutes. Passive acoustic monitoring shall also be 
conducted with Navy assets, such as sonobuoys, already participating in 
the activity. These assets would only detect vocalizing marine mammals 
within the frequency bands monitored by Navy personnel. Passive 
acoustic detections would not provide range or bearing to detected 
animals, and therefore cannot provide locations of these animals. 
Passive acoustic detections would be reported to Lookouts posted in 
aircraft in order to increase vigilance of their visual surveillance.
    (B) A mitigation zone with a radius of 200 yd. (180 m) shall be 
established for small- and medium-caliber gunnery exercises with a 
surface target. The exercise shall not commence if concentrations of 
floating vegetation (kelp paddies) are observed in the mitigation zone. 
Firing shall cease if a marine mammal is sighted within the mitigation 
zone. Firing shall recommence if any one of the following conditions is 
met: The animal is observed exiting the mitigation zone, the animal is 
thought to have exited the mitigation zone based on its course and 
speed, the mitigation zone has been clear from any additional sightings 
for a period of 10 minutes for a firing aircraft, the mitigation zone 
has been clear from any additional sightings for a period of 30 minutes 
for a firing ship, or the intended target location has been 
repositioned more than 400 yd. (370 m) away from the location of the 
last sighting.
    (C) A mitigation zone with a radius of 600 yd. (549 m) shall be 
established for large-caliber gunnery exercises with a surface target. 
The exercise shall not commence if concentrations of floating 
vegetation (kelp paddies) are observed in the mitigation zone. Firing 
shall cease if a marine mammal is sighted within the mitigation zone. 
Firing shall recommence if any one of the following conditions is met: 
The animal is observed exiting the mitigation zone, the animal is 
thought to have exited the mitigation zone based on its course and 
speed, or the mitigation zone has been clear from any additional 
sightings for a period of 30 minutes.
    (D) A mitigation zone with a radius of 900 yd. (823 m) shall be 
established for missile exercises with up to 250 lb NEW and a surface 
target. The exercise shall not commence if concentrations of floating 
vegetation (kelp paddies) are observed in the mitigation zone. Firing 
shall cease if a marine mammal is sighted within the mitigation zone. 
Firing shall recommence if any one of the following conditions is met: 
The animal is observed exiting the mitigation zone, the animal is 
thought to have exited the mitigation zone based on its course and 
speed, or the mitigation zone has been clear from any additional 
sightings for a period of 10 minutes or 30 minutes (depending on 
aircraft type).
    (E) A mitigation zone with a radius of 2,000 yd. (1.8 km) shall be 
established for missile exercises with 251 to 500 lb NEW using a 
surface target. The exercise shall not commence if concentrations of 
floating vegetation (kelp paddies) are observed in the mitigation zone. 
Firing shall cease if a marine mammal is sighted within the mitigation 
zone. Firing shall recommence if any one of the following conditions is 
met: The animal is observed exiting the mitigation zone, the animal is 
thought to have exited the mitigation zone based on its course and 
speed, or the mitigation zone has been clear from any additional 
sightings for a period of 10 minutes or 30 minutes (depending on 
aircraft type).
    (F) A mitigation zone with a radius of 2,500 yd. (2.3 km) around 
the intended impact location for explosive bombs and 1000 yd. (920 m) 
for non-explosive bombs shall be established for bombing exercises. The 
exercise shall not commence if concentrations of floating vegetation 
(kelp paddies) are observed in the mitigation zone. Bombing shall cease 
if a marine mammal is sighted within the mitigation zone. Bombing shall 
recommence if any one of the following conditions is met: The animal is 
observed exiting the mitigation zone, the animal is thought to have 
exited the mitigation zone based on its course and speed, or the 
mitigation zone has been clear from any additional sightings for a 
period of 10 minutes.
    (G) A mitigation zone with a radius of 2.5 nautical miles shall be 
established for sinking exercises. Sinking exercises shall include 
aerial observation beginning 90 minutes before the first firing, visual 
observations from vessels throughout the duration of the exercise, and 
both aerial and vessel observation immediately after any planned or 
unplanned breaks in weapons firing of longer than 2 hours. Prior to 
conducting the exercise, the Navy shall review remotely sensed sea 
surface temperature and sea surface height maps to aid in deciding 
where to release the target ship hulk. The Navy shall also monitor 
using passive acoustics during the exercise. Passive acoustic 
monitoring would be conducted with Navy assets, such as passive ships 
sonar systems or sonobuoys, already participating in the activity. 
These assets would only detect vocalizing marine mammals within the 
frequency bands monitored by Navy personnel. Passive acoustic 
detections would not provide range or bearing to detected animals, and 
therefore cannot provide locations of these animals. Passive acoustic 
detections would be reported to lookouts posted in aircraft and on 
vessels in order to increase vigilance of their visual surveillance. 
Lookouts shall also increase observation vigilance before the use of 
torpedoes or unguided ordnance with a NEW of 500 lb. or greater, or if 
the Beaufort sea state is a 4 or above. The exercise shall not commence 
if concentrations of floating vegetation (kelp paddies) are observed in 
the mitigation zone. The exercise shall cease if a marine mammal, sea 
turtle, or aggregation of jellyfish is sighted within the mitigation 
zone. The exercise shall recommence if any one of the following 
conditions is met: The animal is observed exiting the mitigation zone, 
the animal is thought to have exited the mitigation zone based on a 
determination of its course and speed and the relative motion between 
the animal and the source, or the mitigation zone has been clear from 
any additional sightings for a period of 30 minutes. Upon sinking the 
vessel, the Navy shall conduct post-exercise visual surveillance of the 
mitigation zone for 2

[[Page 10020]]

hours (or until sunset, whichever comes first).
    (H) A mitigation zone of 70 yd. (46 m) shall be established for all 
explosive large-caliber gunnery exercises conducted from a ship. The 
exercise shall not commence if concentrations of floating vegetation 
(kelp paddies) are observed in the mitigation zone. Firing shall cease 
if a marine mammal is sighted within the mitigation zone. Firing shall 
recommence if any one of the following conditions is met: The animal is 
observed exiting the mitigation zone, the animal is thought to have 
exited the mitigation zone based on its course and speed, the 
mitigation zone has been clear from any additional sightings for a 
period of 30 minutes, or the vessel has repositioned itself more than 
140 yd. (128 m) away from the location of the last sighting.
    (v) Mitigation zones for vessels and in-water devices:
    (A) A mitigation zone of 500 yd. (460 m) for observed whales and 
200 yd (183 m) for all other marine mammals (except bow riding 
dolphins) shall be established for all vessel movement during training 
activities, providing it is safe to do so.
    (B) A mitigation zone of 250 yd. (229 m) shall be established for 
all towed in-water devices, providing it is safe to do so.
    (vi) Mitigation zones for non-explosive practice munitions:
    (A) A mitigation zone of 200 yd. (180 m) shall be established for 
small, medium, and large caliber gunnery exercises using a surface 
target. The exercise shall not commence if concentrations of floating 
vegetation (kelp paddies) are observed in the mitigation zone. Firing 
shall cease if a marine mammal is sighted within the mitigation zone. 
Firing shall recommence if any one of the following conditions is met: 
The animal is observed exiting the mitigation zone, the animal is 
thought to have exited the mitigation zone based on its course and 
speed, the mitigation zone has been clear from any additional sightings 
for a period of 10 minutes for a firing aircraft, the mitigation zone 
has been clear from any additional sightings for a period of 30 minutes 
for a firing ship, or the intended target location has been 
repositioned more than 400 yd. (370 m) away from the location of the 
last sighting.
    (B) A mitigation zone of 1,000 yd. (920 m) shall be established for 
bombing exercises. Bombing shall cease if a marine mammal is sighted 
within the mitigation zone. The exercise shall not commence if 
concentrations of floating vegetation (kelp paddies) are observed in 
the mitigation zone. Bombing shall recommence if any one of the 
following conditions is met: The animal is observed exiting the 
mitigation zone, the animal is thought to have exited the mitigation 
zone based on its course and speed, or the mitigation zone has been 
clear from any additional sightings for a period of 10 minutes.
    (C) A mitigation zone of 900 yd. (823 m) shall be established for 
missile exercises (including rockets) using a surface target. The 
exercise shall not commence if concentrations of floating vegetation 
(kelp paddies) are observed in the mitigation zone. Firing shall cease 
if a marine mammal is sighted within the mitigation zone. Firing shall 
recommence if any one of the following conditions is met: The animal is 
observed exiting the mitigation zone, the animal is thought to have 
exited the mitigation zone based on its course and speed, or the 
mitigation zone has been clear from any additional sightings for a 
period of 10 minutes or 30 minutes (depending on aircraft type).
    (3) Stranding response plan. (i) The Navy shall abide by the letter 
of the ``Stranding Response Plan for Major Navy Training Exercises in 
the GOA TMAA Study Area,'' to include the following measures:
    (A) Shutdown procedures. When an Uncommon Stranding Event (USE) 
occurs during a Major Training Exercise (MTE) in the Study Area, the 
Navy shall implement the procedures described below:
    (1) The Navy shall implement a shutdown when advised by a NMFS 
Office of Protected Resources Headquarters Senior Official designated 
in the GOA TMAA Study Area Stranding Communication Protocol that a USE 
involving live animals has been identified and that at least one live 
animal is located in the water. NMFS and the Navy shall maintain a 
dialogue, as needed, regarding the identification of the USE and the 
potential need to implement shutdown procedures.
    (2) Any shutdown in a given area shall remain in effect in that 
area until NMFS advises the Navy that the subject(s) of the USE at that 
area die or are euthanized, or that all live animals involved in the 
USE at that area have left the area (either of their own volition or 
herded).
    (3) If the Navy finds an injured or dead animal floating at sea 
during an MTE, the Navy shall notify NMFS immediately or as soon as 
operational security considerations allow. The Navy shall provide NMFS 
with species or description of the animal(s), the condition of the 
animal(s), including carcass condition if the animal(s) is/are dead, 
location, time of first discovery, observed behavior (if alive), and 
photo or video (if available). Based on the information provided, NFMS 
shall determine if, and advise the Navy whether a modified shutdown is 
appropriate on a case-by-case basis.
    (4) In the event, following a USE, that qualified individuals are 
attempting to herd animals back out to the open ocean and animals are 
not willing to leave, or animals are seen repeatedly heading for the 
open ocean but turning back to shore, NMFS and the Navy shall 
coordinate (including an investigation of other potential anthropogenic 
stressors in the area) to determine if the proximity of mid-frequency 
active sonar training activities or explosive detonations, though 
farther than 14 nautical miles from the distressed animal(s), is likely 
contributing to the animals' refusal to return to the open water. If 
so, NMFS and the Navy shall further coordinate to determine what 
measures are necessary to improve the probability that the animals will 
return to open water and implement those measures as appropriate.
    (B) Within 72 hours of NMFS notifying the Navy of the presence of a 
USE, the Navy shall provide available information to NMFS (per the GOA 
TMAA Study Area Communication Protocol) regarding the location, number 
and types of acoustic/explosive sources, direction and speed of units 
using mid-frequency active sonar, and marine mammal sightings 
information associated with training activities occurring within 80 
nautical miles (148 km) and 72 hours prior to the USE event. 
Information not initially available regarding the 80-nautical miles 
(148-km), 72-hour period prior to the event shall be provided as soon 
as it becomes available. The Navy shall provide NMFS investigative 
teams with additional relevant unclassified information as requested, 
if available.
    (ii) [Reserved]
    (b) [Reserved]


Sec.  218.155  Requirements for monitoring and reporting.

    (a) The Holder of the Authorization must notify NMFS immediately 
(or as soon as operational security considerations allow) if the 
specified activity identified in Sec.  218.150 is thought to have 
resulted in the mortality or injury of any marine mammals, or in any 
take of marine mammals not identified in Sec.  218.152(c).
    (b) The Holder of the LOA must conduct all monitoring and required 
reporting under the LOA, including abiding by the GOA TMAA monitoring 
plan.

[[Page 10021]]

    (c) General notification of injured or dead marine mammals. Navy 
personnel shall ensure that NMFS (regional stranding coordinator) is 
notified immediately (or as soon as operational security considerations 
allow) if an injured or dead marine mammal is found during or shortly 
after, and in the vicinity of, a Navy training activity utilizing mid- 
or high-frequency active sonar, or underwater explosive detonations. 
The Navy shall 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 
that is not in the vicinity of, or during or shortly after, MFAS, HFAS, 
or underwater explosive detonations, the Navy shall report the same 
information as listed above as soon as operationally feasible and 
clearance procedures allow.
    (d) General notification of ship strike. In the event of a ship 
strike by any Navy vessel, at any time or place, the Navy shall do the 
following:
    (1) 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), 
and the time of the strike.
    (2) Report to NMFS as soon as operationally feasible the size and 
length of animal, an estimate of the injury status (ex., dead, injured 
but alive, injured and moving, unknown, etc.), vessel class/type and 
operational status.
    (3) Report to NMFS the vessel length, speed, and heading as soon as 
feasible.
    (4) Provide NMFS a photo or video, if equipment is available.
    (5) Within 2 weeks of the strike, provide NMFS with a detailed 
description of the specific actions of the vessel in the 30-minute 
timeframe immediately preceding the strike, during the event, and 
immediately after the strike (e.g., the speed and changes in speed, the 
direction and changes in direction, other maneuvers, sonar use, etc., 
if not classified); a narrative description of marine mammal sightings 
during the event and immediately after, and any information as to 
sightings prior to the strike, if available; and use established Navy 
shipboard procedures to make a camera available to attempt to capture 
photographs following a ship strike.
    (e) Communication plan. The Navy and NMFS shall develop a 
communication plan that will include all of the communication protocols 
(phone trees, etc.) and associated contact information required for 
NMFS and the Navy to carry out the necessary expeditious communication 
required in the event of a stranding or ship strike, including 
information described in the proposed notification measures above.
    (f) Annual GOA TMAA monitoring report. The Navy shall submit an 
annual report of the GOA TMAA monitoring describing the implementation 
and results from the previous calendar year. Data collection methods 
shall be standardized across range complexes and study areas to allow 
for comparison in different geographic locations. Although additional 
information will be gathered, the protected species observers 
collecting marine mammal data pursuant to the GOA TMAA monitoring plan 
shall, at a minimum, provide the same marine mammal observation data 
required in Sec.  218.155. The report shall be submitted either 90 days 
after the calendar year, or 90 days after the conclusion of the 
monitoring year to be determined by the Adaptive Management process. 
The GOA TMAA Monitoring Report may be provided to NMFS within a larger 
report that includes the required Monitoring Plan reports from multiple 
range complexes and study areas (the multi-Range Complex Annual 
Monitoring Report). Such a report would describe progress of knowledge 
made with respect to monitoring plan study questions across all Navy 
ranges associated with the Integrated Comprehensive Monitoring Program. 
Similar study questions shall be treated together so that progress on 
each topic shall be summarized across all Navy ranges. The report need 
not include analyses and content that does not provide direct 
assessment of cumulative progress on the monitoring plan study 
questions.
    (g) Annual GOA TMAA exercise reports. Each year, the Navy shall 
submit a preliminary report detailing the status of authorized sound 
sources within 21 days after the anniversary of the date of issuance of 
the LOA. Each year, the Navy shall submit a detailed report within 3 
months after the anniversary of the date of issuance of the LOA. The 
annual report shall contain information on Major Training Exercises 
(MTEs), Sinking Exercise (SINKEX) events, and a summary of all sound 
sources used, as described in paragraph (g)(3) of this section. The 
analysis in the detailed report shall be based on the accumulation of 
data from the current year's report and data collected from previous 
the report. The detailed reports shall contain information identified 
in paragraphs (g)(1) through (4) of this section.
    (1) MFAS/HFAS Major Training Exercises--This section shall contain 
the following information for Major Training Exercises conducted in the 
GOA TMAA:
    (i) Exercise Information (for each MTE):
    (A) Exercise designator.
    (B) Date that exercise began and ended.
    (C) Location.
    (D) Number and types of active sources used in the exercise.
    (E) Number and types of passive acoustic sources used in exercise.
    (F) Number and types of vessels, aircraft, etc., participating in 
exercise.
    (G) Total hours of observation by lookouts.
    (H) Total hours of all active sonar source operation.
    (I) Total hours of each active sonar source bin.
    (J) Wave height (high, low, and average during exercise).
    (ii) Individual marine mammal sighting information for each 
sighting in each exercise when mitigation occurred:
    (A) Date/Time/Location of sighting.
    (B) Species (if not possible, indication of whale/dolphin/
pinniped).
    (C) Number of individuals.
    (D) Initial Detection Sensor.
    (E) Indication of specific type of platform observation made from 
(including, for example, what type of surface vessel or testing 
platform).
    (F) Length of time observers maintained visual contact with marine 
mammal.
    (G) Sea state.
    (H) Visibility.
    (I) Sound source in use at the time of sighting.
    (J) Indication of whether animal is <200 yd, 200 to 500 yd, 500 to 
1,000 yd, 1,000 to 2,000 yd, or >2,000 yd from sonar source.
    (K) Mitigation implementation. Whether operation of sonar sensor 
was delayed, or sonar was powered or shut down, and how long the delay 
was.
    (L) If source in use is hull-mounted, true bearing of animal from 
ship, true direction of ship's travel, and estimation of animal's 
motion relative to ship (opening, closing, parallel).
    (M) Observed behavior. Lookouts shall report, in plain language and 
without trying to categorize in any way, the observed behavior of the 
animals (such as animal closing to bow ride, paralleling course/speed, 
floating on surface and not swimming, etc.) and if any calves present.
    (iii) An evaluation (based on data gathered during all of the MTEs) 
of the effectiveness of mitigation measures designed to minimize the 
received level

[[Page 10022]]

to which marine mammals may be exposed. This evaluation shall identify 
the specific observations that support any conclusions the Navy reaches 
about the effectiveness of the mitigation.
    (2) SINKEXs. This section shall include the following information 
for each SINKEX completed that year:
    (i) Exercise information (gathered for each SINKEX):
    (A) Location.
    (B) Date and time exercise began and ended.
    (C) Total hours of observation by lookouts before, during, and 
after exercise.
    (D) Total number and types of explosive source bins detonated.
    (E) Number and types of passive acoustic sources used in exercise.
    (F) Total hours of passive acoustic search time.
    (G) Number and types of vessels, aircraft, etc., participating in 
exercise.
    (H) Wave height in feet (high, low, and average during exercise).
    (I) Narrative description of sensors and platforms utilized for 
marine mammal detection and timeline illustrating how marine mammal 
detection was conducted.
    (ii) Individual marine mammal observation (by Navy lookouts) 
information (gathered for each marine mammal sighting) for each 
sighting in each exercise that required mitigation to be implemented:
    (A) Date/Time/Location of sighting.
    (B) Species (if not possible, indicate whale, dolphin, or 
pinniped).
    (C) Number of individuals.
    (D) Initial detection sensor.
    (E) Length of time observers maintained visual contact with marine 
mammal.
    (F) Sea state.
    (G) Visibility.
    (H) Whether sighting was before, during, or after detonations/
exercise, and how many minutes before or after.
    (I) Distance of marine mammal from actual detonations (or target 
spot if not yet detonated).
    (J) Observed behavior. Lookouts shall report, in plain language and 
without trying to categorize in any way, the observed behavior of the 
animal(s) (such as animal closing to bow ride, paralleling course/
speed, floating on surface and not swimming etc.), including speed and 
direction and if any calves present.
    (K) Resulting mitigation implementation. Indicate whether explosive 
detonations were delayed, ceased, modified, or not modified due to 
marine mammal presence and for how long.
    (L) If observation occurs while explosives are detonating in the 
water, indicate munition type in use at time of marine mammal 
detection.
    (3) Summary of sources used.
    (i) This section shall include the following information summarized 
from the authorized sound sources used in all training events:
    (A) Total annual hours or quantity (per the LOA) of each bin of 
sonar or other non-impulsive source;
    (B) Total annual number of each type of explosive exercises (of 
those identified as part of the ``Specified Activity'' in this proposed 
rule) and total annual expended/detonated rounds (missiles, bombs, 
sonobuoys, etc.) for each explosive bin.
    (4) Geographic information presentation. The reports shall present 
an annual (and seasonal, where practical) depiction of training 
exercises and testing bin usage geographically across the Study Area.
    (g) Sonar exercise notification. The Navy shall submit to NMFS 
(contact as specified in the LOA) an electronic report within fifteen 
calendar days after the completion of any major training exercise 
indicating:
    (i) Location of the exercise.
    (ii) Beginning and end dates of the exercise.
    (iii) Type of exercise.
    (h) Five-year close-out exercise report. This report shall be 
included as part of the 2021 annual exercise report. This report shall 
provide the annual totals for each sound source bin with a comparison 
to the annual allowance and the 5-year total for each sound source bin 
with a comparison to the 5-year allowance. Additionally, if there were 
any changes to the sound source allowance, this report shall include a 
discussion of why the change was made and include the analysis to 
support how the change did or did not result in a change in the SEIS 
and final rule determinations. The report shall be submitted 3 months 
after the expiration of this subpart. NMFS shall submit comments on the 
draft close-out report, if any, within 3 months of receipt. The report 
shall be considered final after the Navy has addressed NMFS' comments, 
or 3 months after the submittal of the draft if NMFS does not provide 
comments.


Sec.  218.156  Applications for letters of authorization (LOA).

    To incidentally take marine mammals pursuant to the regulations in 
this subpart, the U.S. citizen (as defined by Sec.  216.106 of this 
chapter) conducting the activity identified in Sec.  218.150(c) (the 
U.S. Navy) must apply for and obtain either an initial LOA in 
accordance with Sec.  218.157 or a renewal under Sec.  218.158.


Sec.  218.157  Letters of authorization (LOA).

    (a) An LOA, unless suspended or revoked, shall be valid for a 
period of time not to exceed the period of validity of this subpart.
    (b) Each LOA shall set forth:
    (1) Permissible methods of incidental taking;
    (2) Means of effecting the least practicable adverse impact on the 
species, its habitat, and on the availability of the species for 
subsistence uses (i.e., mitigation); and
    (3) Requirements for mitigation, monitoring and reporting.
    (c) Issuance and renewal of the LOA shall be based on a 
determination that the total number of marine mammals taken by the 
activity as a whole shall have no more than a negligible impact on the 
affected species or stock of marine mammal(s).


Sec.  218.158  Renewals and modifications of letters of authorization 
(LOA) and adaptive management.

    (a) A letter of authorization issued under Sec. Sec.  216.106 and 
218.157 of this chapter for the activity identified in Sec.  218.150(c) 
shall be renewed or modified upon request of the applicant, provided 
that:
    (1) The proposed specified activity and mitigation, monitoring, and 
reporting measures, as well as the anticipated impacts, are the same as 
those described and analyzed for these regulations (excluding changes 
made pursuant to the adaptive management provision of this chapter), 
and;
    (2) NMFS determines that the mitigation, monitoring, and reporting 
measures required by the previous LOA under these regulations were 
implemented.
    (b) For LOA modification or renewal requests by the applicant that 
include changes to the activity or the mitigation, monitoring, or 
reporting (excluding changes made pursuant to the adaptive management 
provision of this chapter) that do not change the findings made for the 
regulations or result in no more than a minor change in the total 
estimated number of takes (or distribution by species or years), NMFS 
may publish a notice of proposed LOA in the Federal Register, including 
the associated analysis illustrating the change, and solicit public 
comment before issuing the LOA.
    (c) A LOA issued under Sec.  216.106 and Sec.  218.157 of this 
chapter for the activity identified in Sec.  218.154 of this chapter 
may be modified by NMFS under the following circumstances:

[[Page 10023]]

    (1) Adaptive management. NMFS may modify and augment the existing 
mitigation, monitoring, or reporting 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 the mitigation and monitoring.
    (i) Possible sources of data that could contribute to the decision 
to modify the mitigation, monitoring, and reporting measures in an LOA:
    (A) Results from Navy's monitoring from the previous year(s);
    (B) Results from other marine mammal and/or sound research or 
studies; or
    (C) Any information that reveals marine mammals may have been taken 
in a manner, extent, or number not authorized by these regulations or 
subsequent LOA.
    (ii) If, through adaptive management, the modifications to the 
mitigation, monitoring, or reporting measures are substantial, NMFS 
would publish a notice of proposed LOA in the Federal Register and 
solicit public comment.
    (2) Emergencies. 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.  218.152(c), an LOA may be modified 
without prior notification and an opportunity for public comment. 
Notification would be published in the Federal Register within 30 days 
of the action.

[FR Doc. 2016-03622 Filed 2-25-16; 8:45 am]
 BILLING CODE 3510-22-P