[Federal Register Volume 77, Number 4 (Friday, January 6, 2012)]
[Proposed Rules]
[Pages 842-894]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-33600]



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Vol. 77

Friday,

No. 4

January 6, 2012

Part II





Department of Commerce





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National Oceanic and Atmospheric Administration





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50 CFR Part 218





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

  Federal Register / Vol. 77 , No. 4 / Friday, January 6, 2012 / 
Proposed Rules  

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 218

[Docket No. 110808485-1534-01]
RIN 0648-BB14


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

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

ACTION: Proposed rule; request for comments.

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SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for 
authorization to take marine mammals, by harassment, incidental to 
conducting operations of Surveillance Towed Array Sensor System 
(SURTASS) Low Frequency Active (LFA) sonar in areas of the world's 
oceans (with the exception of Arctic and Antarctic waters and certain 
geographic restrictions), from August 16, 2012, through August 15, 
2017. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is 
proposing regulations to govern that take and requests information, 
suggestions, and comments on these proposed regulations.

DATES: Comments and information must be received no later than February 
6, 2012.

ADDRESSES: You may submit comments, identified by 0648-BB14, by any one 
of the following methods:
     Electronic Submissions: Submit all electronic public 
comments via the Federal eRulemaking Portal: http://www.regulations.gov.
     Hand delivery or mailing of paper, disk, or CD-ROM 
comments should be addressed to P. Michael Payne, Chief, Permits, 
Conservation and Education Division, Office of Protected Resources, 
National Marine Fisheries Service, 1315 East-West Highway, Silver 
Spring, MD 20910.
    Instructions: All comments received are a part of the public record 
and will generally be posted to http://www.regulations.gov without 
change. All Personal Identifying Information (for example, name, 
address, etc.) voluntarily submitted by the commenter may be publicly 
accessible. Do not submit Confidential Business Information or 
otherwise sensitive or protected information.
    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, WordPerfect, or 
Adobe PDF file formats only. To help NMFS process and review comments 
more efficiently, please use only one method to submit comments.

FOR FURTHER INFORMATION CONTACT: Jeannine Cody, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Availability

    The public may obtain an electronic copy of the Navy's application 
by writing to the address specified above this section (see ADDRESSES), 
telephoning the contact listed above this section (see FOR FURTHER 
INFORMATION CONTACT), or by visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications. The Navy 
published a Federal Register Notice of Availability of a Draft 
Supplemental Environmental Impact Statement/Supplemental Overseas 
Environmental Impact Statement (DSEIS/SOEIS) for employment of SURTASS 
LFA sonar on August 19, 2011. The public may view the document at: 
http://www.surtass-lfa-eis.com. NMFS is participating in the 
development of the Navy's DSEIS/SOEIS as a cooperating agency under the 
National Environmental Policy Act of 1972.

Background

    Sections 101(a)(5)(A) and (D) of the Marine Mammal Protection Act 
of 1972, as amended (MMPA; 16 U.S.C. 1361 et seq.), direct the 
Secretary of Commerce (Secretary) 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 during 
periods of not more than five consecutive years each if certain 
findings are made and 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 shall be granted if NMFS finds that the taking will 
have a negligible impact on the species or stock(s), and will not have 
an unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses (where relevant). The authorization must 
set forth the permissible methods of taking, other means of effecting 
the least practicable adverse impact on the species or stock and its 
habitat, and requirements pertaining to the mitigation, monitoring and 
reporting of such taking.
    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) amended the MMPA by removing the ``small numbers'' and ``specified 
geographical region'' provisions and amended the definition of 
``harassment'' as it applies to a ``military readiness activity'' (as 
defined in section 315(f) of Public Law 107-314; 16 U.S.C. 703 note) to 
read as follows (Section 3(18)(B) of the MMPA):

    (i) Any act that injures or has the significant potential to 
injure a marine mammal or marine mammal stock in the wild [Level A 
Harassment]; or
    (ii) Any act that disturbs or is likely to disturb a marine 
mammal or marine mammal stock in the wild by causing disruption of 
natural behavior patterns, including, but not limited to, migration, 
surfacing, nursing, breeding, feeding, or sheltering, to a point 
where such behavioral patterns are abandoned or significantly 
altered [Level B Harassment].

Summary of Request

    On August 17, 2011, NMFS received an application from the U.S. Navy 
requesting authorization for the take of individuals of 94 species of 
marine mammals (70 cetaceans and 24 pinnipeds), by harassment, 
incidental to upcoming routine training and testing of the SURTASS LFA 
sonar system, as well as the use of the system on a maximum of four 
U.S. Naval ships during military operations in certain areas of the 
Pacific, Atlantic, and Indian Oceans and the Mediterranean Sea from 
August 16, 2012 through August 15, 2017. These routine training and 
testing and military operations are classified as military readiness 
activities. The Navy states, and NMFS concurs, that these military 
readiness activities may incidentally take marine mammals present 
within the Navy's operation areas by exposing them to sound from low-
frequency active sonar sources. The Navy requests authorization to take 
individuals of 94 species of marine mammals by Level A and Level B 
Harassment, although as discussed later in this document, Level A 
Harassment will likely be avoided through the implementation of the 
Navy's proposed mitigation measures.
    This is NMFS' third rule making for SURTASS LFA sonar operations 
under the MMPA. NMFS' current five-year

[[Page 843]]

regulations governing incidental takings incidental to SURTASS LFA 
sonar activities and the related Letters of Authorizations (LOA) expire 
on August 15, 2012. NMFS published the first rule, effective from 
August 2002 through August 2007, on July 16, 2002 (67 FR 46712), and 
published the second rule on August 21, 2007 (72 FR 46846). For this 
proposed rule making, the Navy is proposing to conduct the same types 
of sonar activities as they have conducted over the past nine years.

Description of the Specified Activities

Purpose and Background

    The Navy's mission is to maintain, train, equip, and operate 
combat-ready naval forces capable of accomplishing American strategic 
objectives, deterring maritime aggression, and maintaining freedom of 
the seas. Section 5062 of Title 10 of the United States Code directs 
the Secretary of the Navy and Chief of Naval Operations (CNO) to ensure 
the readiness of the U.S. naval forces.
    The Secretary of the Navy and the CNO have established that anti-
submarine warfare (ASW) is a critical part of the Navy's mission that 
requires access to both the open-ocean and littoral environments and 
continual training to prepare for all potential threats. The Navy is 
challenged by the increased difficulty in locating undersea threats 
solely by using passive acoustic technologies due to the advancement 
and use of quieting technologies in diesel-electric and nuclear 
submarines. The range at which the Navy's ASW assets are able to 
identify submarine threats is decreasing, and at the same time, 
improvements in torpedo design are extending the effective weapons 
range of subsea threats to the U.S. naval fleet.
    To address these changing requirements for ASW readiness, the Navy 
developed SURTASS LFA sonar, which provides the Navy with a reliable 
and dependable system for long-range detection of quieter, harder-to-
find submarines. Because low-frequency (LF) sound travels in seawater 
for greater distances than higher frequency sound, the Navy states that 
the SURTASS LFA sonar system would meet the need for improved detection 
and tracking of new-generation submarines at a longer range and would 
maximize the opportunity for U.S. armed forces to safely react to, and 
defend against, potential submarine threats while remaining a safe 
distance beyond a submarine's effective weapons range. Thus, the Navy 
believes that the active acoustic component in the SURTASS LFA sonar is 
an important augmentation to its passive and tactical systems, as its 
long-range detection capabilities can effectively counter the threat to 
the U.S. Navy and national security interests posed by quiet, diesel 
submarines.

Specified Activities

    As previously mentioned, the Navy has requested MMPA authorization 
to take marine mammals incidental to the operation of up to four 
SURTASS LFA sonar systems for routine training and testing as well as 
for the use of the system during military operations from August 16, 
2012 through August 15, 2017. The SURTASS LFA sonar system is a long-
range, LF sonar (between 100 and 500 Hertz (Hz)) that has both active 
and passive components (see the Description of SURTASS LFA Sonar 
section later in this document). Use of the LFA sonar system could 
occur in the Pacific, Atlantic and Indian Oceans, and the Mediterranean 
Sea on a maximum of four naval surveillance vessels: the USNS ABLE, 
USNS EFFECTIVE, USNS IMPECCABLE, and the USNS VICTORIOUS. The Navy 
states that they will not operate SURTASS LFA sonar in Arctic and 
Antarctic waters. Further, the Navy also proposes to operate SURTASS 
LFA sonar such that the sound field does not exceed 180 decibels (dB) 
within 22 kilometers (km) (13.7 miles (mi); 12 nautical miles (nm) of 
land; or in proposed offshore biologically important areas (OBIA) for 
marine mammals, identified later in this document, in the Navy's 
application, and in the Navy's 2011 DSEIS/SOEIS (see Geographic 
Restrictions section later in this document).
    Because of uncertainties in the world's political climate, the Navy 
cannot predict a detailed account of future operating locations and 
conditions. However, for analytical purposes, the Navy has developed a 
nominal annual deployment schedule and operational concept based on 
current LFA sonar operations since January 2003 and projected naval 
fleet requirements (See Table 1).
    The Navy anticipates that a normal SURTASS LFA sonar deployment 
schedule for a single vessel would involve approximately 294 days per 
year at sea, which includes 240 days of active sonar transmissions and 
54 days of transit. SURTASS LFA sonar would operate day and night in a 
variety of weather conditions. NMFS refers the reader to Table 1 for 
additional details on the nominal annual deployment schedule for 
SURTASS LFA sonar vessels.

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

Potential SURTASS LFA Sonar Operational Areas

    Figure 1 depicts the potential areas of operation for SURTASS LFA 
sonar. Based on the Navy's current operational requirements, potential 
operations for SURTASS LFA sonar vessels from August 2012 through 
August 2017 would most likely include areas located in the Pacific, 
Indian, and Atlantic Oceans and Mediterranean Sea.
    The Navy will not operate SURTASS LFA sonar in polar regions (i.e., 
Arctic and Antarctic waters) of the world (see shaded areas in Figure 
1). The Arctic Ocean, the Bering Sea (including Bristol Bay and Norton 
Sound), portions of the Norwegian, Greenland, and Barents Seas north of 
72[deg] North (N) latitude, plus Baffin Bay, Hudson Bay, and the Gulf 
of St. Lawrence would be non-operational areas for SURTASS LFA sonar. 
In the Antarctic, the Navy will not conduct SURTASS LFA operations in 
areas south of 60[deg] South (S) latitude. The Navy has excluded polar 
waters from operational planning because of the inherent inclement 
weather conditions and the navigational and operational (equipment) 
danger that icebergs pose to SURTASS LFA sonar vessels.

[[Page 844]]

[GRAPHIC] [TIFF OMITTED] TP06JA12.000

    The Navy must anticipate, or predict, where they have to operate in 
the next five years or so for the MMPA authorization. Naval forces are 
presently operating in several areas strategic to U.S national and 
international interests, including areas in the Atlantic Ocean, the 
Mediterranean Sea, the Indian Ocean and Persian Gulf, and the Pacific 
Rim. National Security needs may dictate that many of these operational 
areas will be close to ports and choke points, such as entrances to 
straits, channels, and canals. It is anticipated that many future naval 
conflicts are likely to occur within littoral or coastal areas. 
However, it is infeasible for the Navy to analyze all potential mission 
areas for all species and stocks for all seasons. Instead, the Navy 
projects where it intends to test, train, and operate for the next 
five-year authorization period based on today's political climate and 
provides NMFS with risk estimates for marine mammal stocks in the 
proposed areas of operation.
    For this third rulemaking, the Navy has modeled and analyzed 19 
operational areas for SURTASS LFA operations that would be relevant to 
U.S. national security interests (see Table 2). They include the 
following modeled areas: East of Japan; north Philippine Sea; west 
Philippine Sea; offshore Guam; Sea of Japan; East China Sea; the south 
China Sea; the northwest Pacific Ocean; the Hawai'i Range Complex; 
Offshore Southern California in the Southern California (SOCAL) Range 
Complex; the western Atlantic in the Atlantic Fleet Active Sonar 
(AFAST) Study Area/Jacksonville (JAX) operational area (OPAREA); the 
eastern North Atlantic (western approach); the Mediterranean and 
Ligurian Seas; the Arabian Sea; the Andaman Sea (approaches to the 
Strait of Malacca); the Panama Canal (western approach); and the 
northeast Australian Coast.

  Table 2--Potential SURTASS LFA Sonar Operating Areas That the Navy Modeled for the DSEIS/OEIS (DoN, 2011) and
                                            the MMPA LOA Application
----------------------------------------------------------------------------------------------------------------
                                      Location  (latitude/                               Location  (latitude/
          Modeled site                     longitude)               Modeled site              longitude)
----------------------------------------------------------------------------------------------------------------
East of Japan...................  38[deg] N, 148[deg] E         Hawaii South         19.5[deg] N, 158.5[deg] W.
                                                                 (Hawai'i Range
                                                                 Complex).
North Philippine Sea............  29[deg] N, 136[deg] E         Offshore Southern    32[deg] N, 120[deg] W.
                                                                 California
                                                                 (Southern
                                                                 California (SOCAL)
                                                                 Range Complex).
West Philippine Sea.............  22[deg] N, 124[deg] E         Western Atlantic     30[deg] N, 78[deg] W.
                                                                 (off Florida)
                                                                 (Atlantic Fleet
                                                                 Active Sonar
                                                                 (AFAST) Study Area/
                                                                 Jacksonville.
Offshore Guam (Mariana Islands    11[deg] N, 145[deg] E         Eastern North        56.5[deg] N, 10[deg] W.
 Range Complex, outside Mariana                                  Atlantic (western
 Trench).                                                        approach).
Sea of Japan....................  39[deg] N, 132[deg] E         Mediterranean Sea--  43[deg] N, 8[deg] E.
                                                                 Ligurian Sea.
East China Sea..................  26[deg] N, 125[deg] E         Arabian Sea........  20[deg]N, 65[deg]E.
South China Sea.................  21[deg] N, 119[deg] E         Andaman Sea          7.5[deg] N, 96[deg] E.
                                                                 (approaches to the
                                                                 Strait of Malacca).
NW Pacific 25[deg] to 40[deg] N.  30[deg] N, 165[deg] E         Panama Canal         5[deg] N, 81[deg] W.
                                                                 (western approach).
NW Pacific 10[deg] to 25[deg] N.  15[deg] N, 165[deg] E         Northeast            23[deg] S, 155[deg] E.
                                                                 Australian Coast.
Hawai'i North (Hawai'i Range      25[deg] N, 158[deg] W                              ...........................
 Complex).
----------------------------------------------------------------------------------------------------------------


[[Page 845]]

    Acoustic stimuli (i.e., increased underwater sound) generated 
during the transmission of low-frequency acoustic signals by the 
SURTASS LFA sonar system has the potential to cause take of marine 
mammals in the operational areas. The operation of the SURTASS LFA 
sonar system during at-sea operations would result in the generation of 
sound or pressure waves in the water at or above levels that NMFS has 
determined would result in take. This is the principal means of marine 
mammal taking associated with these military readiness activities and 
the Navy has requested an authorization to take 94 species of marine 
mammals by Level A and Level B harassment. At no point are there 
expected to be more than four systems in use, and thus this proposed 
rule analyzes the impacts on marine mammals due to the deployment of up 
to four LFA sonar systems from 2012 through 2017.
    In addition to the use of active acoustic sources, the Navy's 
activities include the operation and movement of vessels that are 
necessary to conduct the routine training and testing as well as the 
use of the system during military operations. This document also 
analyzes the effects of this part of the activities. However, NMFS does 
not anticipate take to result from collision with any of the four 
SURTASS LFA vessels because each vessel moves at a relatively slow 
speed, for a relatively short period of time. It is likely that any 
marine mammal would be able to avoid the surveillance vessels.

Description of SURTASS LFA Sonar

    SONAR is an acronym for Sound Navigation and Ranging, and its 
definition includes any system (biological or mechanical) that uses 
underwater sound, or acoustics, for detection, monitoring, and/or 
communications. Active sonar is the transmission of sound energy for 
the purpose of sensing the environment by interpreting features of 
received signals. Active sonar detects objects by creating a sound 
pulse or ping that is transmitted through the water and reflects off 
the target, returning in the form of an echo. Passive sonar detects the 
transmission of sound waves created by an object.
    The SURTASS LFA sonar system is a long-range, all-weather sonar 
system that has both active and passive components. LFA, the active 
system component (which allows for the detection of an object that is 
not generating noise), is comprised of source elements (called 
projectors) suspended vertically on a cable beneath the surveillance 
vessel. The projectors produce an active sound pulse (i.e., a ping) by 
converting electrical energy to mechanical energy by setting up 
vibrations or pressure disturbances within the water to produce a ping. 
The Navy uses LFA as an augmentation to SURTASS operations when passive 
system performance is inadequate. SURTASS, the passive part of the 
system, uses hydrophones (i.e., underwater microphones) to detect sound 
emitted or reflected from submerged targets, such as submarines. The 
SURTASS hydrophones are mounted on a horizontal line array that is 
towed behind the surveillance vessel. The Navy then processes and 
evaluates the returning signals or echoes, which are usually below 
background or ambient sound level, to identify and classify potential 
underwater targets.

LFA Active Component

    The active component of the SURTASS LFA sonar system consists of up 
to 18 projectors suspended beneath the surveillance vessel in a 
vertical line array. The expected water depth at the center of the 
array is approximately 400 ft (121.9 m). The SURTASS LFA sonar 
projectors transmit in the low-frequency band (between 100 and 500 Hz) 
and the Navy will not transmit the SURTASS LFA sonar signal at a 
frequency greater than 500 Hz. The source level of an individual 
projector in the SURTASS LFA sonar array is approximately 215 dB re: 1 
[micro]Pa at 1 m or less. (Sound pressure is the sound force per unit 
area and is usually measured in micropascals ([mu]Pa), where one Pascal 
(Pa) is the pressure resulting from a force of one newton exerted over 
an area of one square meter. The commonly used reference pressure level 
in underwater acoustics is 1 [mu]Pa at 1 m, and the units are decibels 
(dB) re: 1 [mu]Pa at 1 m). Because of the physics involved in acoustic 
beamforming (i.e., a method of mapping noise sources by differentiating 
sound levels based upon the direction from which they originate) and 
sound transmission loss processes, the SURTASS LFA sonar array cannot 
have a sound pressure level (SPL) higher than the SPL of an individual 
projector.
    The SURTASS LFA sonar acoustic transmission is an omnidirectional 
beam (a full 360 degrees ([deg])) in the horizontal plane. The LFA 
sonar system also has a narrow vertical beam that the vessel's crew can 
steer above or below the horizontal plane. The typical SURTASS LFA 
sonar signal is not a constant tone, but rather a transmission of 
various signal types that vary in frequency and duration (including 
continuous wave (CW) and frequency-modulated (FM) signals). A complete 
sequence of sound transmissions, also referred to by the Navy as a 
``ping'' or a wavetrain, can last as short as six seconds (sec) to as 
long as 100 sec with an average length of 60 sec. Within each ping, the 
duration of any continuous frequency sound transmission is no longer 
than 10 sec and the time between pings is typically from six to 15 
minutes (min). Based on the Navy's historical operating parameters over 
the past nine years, the average duty cycle (i.e., the ratio of sound 
``on'' time to total time) for LFA sonar is normally 7.5 to 10 percent 
and the duty cycle is not expected to exceed 20 percent.

Compact LFA Active Component

    At present, the USNS IMPECCABLE is the only naval vessel with an 
operational LFA sonar system. To meet future undersea warfare 
requirements in littoral waters, the Navy has developed a compact LFA 
(CLFA) sonar system now deployed on its three smaller surveillance 
vessels (i.e., the USNS ABLE, EFFECTIVE, and VICTORIOUS). In the 
application, the Navy indicates that the operational characteristics of 
the active component CLFA are comparable to the existing LFA systems 
and that the potential impacts from CLFA will be similar to the effects 
from the existing LFA sonar system. CLFA consists of smaller projectors 
that weigh 142,000 lbs (64,410 kilograms (kg)), which is 182,000 lbs 
(82,554 kg) less that the mission weight of the LFA projectors on the 
USNS IMPECCABLE. The CLFA sonar system also consists of up to 18 
projectors suspended beneath the surveillance vessel in a vertical line 
array and the CLFA sonar projectors transmit in the low-frequency band 
(also between 100 and 500 Hz). Similar to the active component of the 
LFA system, the source level of an individual projector in the CLFA 
sonar array is approximately 215 dB re: 1 [micro]Pa or less.
    For the analysis in this document, NMFS will use the term LFA to 
refer to both the LFA sonar system and/or the CLFA sonar system, unless 
otherwise specified.

SURTASS Passive Component

    The passive component of the SURTASS LFA system consists of a 
SURTASS Twin-line (TL-29A) horizontal line array mounted with 
hydrophones. The Y-shaped array is 1,000 ft (305 m) in length and has 
an operational depth of 500 to 1,500 ft (152.4 to 457.2 m). The SURTASS 
LFA sonar vessel typically maintains a speed of at least 3.4 mph (5.6 
km/hr; 3 knots (kts)) to tow the array astern of the vessel in the 
correct horizontal configuration.

[[Page 846]]

High-Frequency Active Sonar

    Although technically not part of the SURTASS LFA sonar system, the 
Navy also proposes to use a high-frequency sonar system, called the 
High Frequency Marine Mammal Monitoring sonar (HF/M3 sonar), developed 
by the Navy and Scientific Solutions, Inc., to detect and locate marine 
mammals within the SURTASS LFA sonar operational areas. This enhanced 
commercial fish-finding sonar, mounted at the top of the SURTASS LFA 
sonar vertical line array, has a source level of 220 dB re: 1 [micro]Pa 
at 1 m with a frequency range from 30 to 40 kilohertz (kHz). The duty 
cycle is variable, but is normally below between three to four percent 
and the maximum pulse duration is 40 milliseconds. The HF/M3 sonar has 
four transducers with 8[deg] horizontal and 10[deg] vertical 
beamwidths, which sweep a full 360[deg] in the horizontal plane every 
45 to 60 sec with a maximum range of approximately 1.2 mi (2 km).

Vessel Specifications

    The Navy proposes to deploy the SURTASS LFA sonar system on a 
maximum of four U.S. Naval ships: the USNS ABLE (T-AGOS 20), the USNS 
EFFECTIVE (T-AGOS 21), the USNS IMPECCABLE (T-AGOS 23) and the USNS 
VICTORIOUS (T-AGOS 19).
    The USNS ABLE, EFFECTIVE, and VICTORIOUS, are twin-hulled ocean 
surveillance ships. Each vessel has a length of 235 feet (ft) (71.6 
meters (m)); a beam of 93.6 ft (28.5 m); a maximum draft of 25 ft (7.6 
m); and a full load displacement of 3,396 tons (3,451 metric tons). A 
twin-shaft diesel electric engine provides 3,200 horsepower (hp), which 
drives two propellers.
    The USNS IMPECCABLE, also a twin-hulled ocean surveillance ship, 
has a length of 281.5 ft (85.8 m); a beam of 95.8 ft (29.2 m); a 
maximum draft of 26 ft (7.9 m); and a full load displacement of 5,368 
tons (5,454 metric tons). A twin-shaft diesel electric engine provides 
5,000 hp, which drives two propellers.
    The operational speed of each vessel during sonar operations will 
be approximately 3.4 miles per hour (mph) (5.6 km per hour (km/hr); 3 
kts) and each vessel's cruising speed outside of sonar operations would 
be approximately 11.5 to 14.9 mph (18.5 to 24.1 km/hr; 10 to 13 kts). 
The expected minimum water depth at which the SURTASS LFA vessel would 
operate is 656.2 ft (200 m) and the vessel will generally travel in 
straight lines or in oval-shaped (i.e., racetrack) patterns depending 
on the operational scenario. Also, each SURTASS LFA sonar vessel would 
operate independently of, or in conjunction with, other naval air, 
surface or submarine assets.
    Each vessel also has an observation area on the bridge from where 
lookouts will monitor for marine mammals before and during the proposed 
sonar operations. When stationed on the bridge of the USNS ABLE, 
EFFECTIVE, or VICTORIOUS, the lookout's eye level will be approximately 
32 ft (9.7 m) above sea level providing an unobstructed view around the 
entire vessel. For the USNS IMPECCABLE, the lookout's eye level will be 
approximately 45 ft (13.7 m) above sea level.

Description of Real-Time SURTASS LFA Sonar Sound Field Modeling

    This section explains how the Navy will determine the propagation 
of LFA sonar signals in the ocean and the distance from the SURTASS LFA 
sonar source to the 180-dB re: 1 [micro]Pa at 1 m isopleth (i.e., the 
basis for the proposed LFA sonar mitigation zone for marine mammals). 
NMFS provides this description to aid the public's understanding of 
this action. However, the actual physics governing the propagation of 
SURTASS LFA sound signals is extremely complex and dependent on 
numerous in-situ environmental factors.
    Prior to commencing and during SURTASS LFA transmissions, the sonar 
operators on the vessel will measure oceanic conditions (such as sea 
water temperature, salinity, and depth) in the proposed action area. 
This information is required for the sonar technicians to accurately 
determine the speed at which sound travels and to determine the path 
that the sound would take through the water column at a particular 
location (i.e., the speed of sound in seawater varies directly with 
depth, temperature, and salinity).
    The sonar operators use the near-real time environmental data and 
the Navy's underwater acoustic performance prediction models (updated 
every 12 hours or more frequently when meteorological or oceanographic 
conditions change) to generate a plot of sound speed versus depth, 
typically referred to as a sound speed profile (SSP). The SSP enables 
the technicians to determine the sound field by predicting the received 
levels of sound at various distances from the SURTASS LFA sonar source 
location. Modeling of the sound field in near-real time provides the 
information necessary to modify SURTASS LFA operations, including the 
delay or suspension of LFA sonar transmissions for mitigation.
    Subchapter 3.1.2 of the SURTASS LFA Sonar 2011 DSEIS/SOEIS (DoN, 
2011) discusses some of the environmental factors affecting sound 
propagation. Appendix B of the 2001 SURTASS LFA Sonar FOEIS/EIS (DoN, 
2001) also provides an understanding concerning the general conditions 
of sound speed in the oceans. NMFS refers the public to these documents 
at http://www.surtass-lfa-eis.com for additional information.

Comments and Responses

    On August 30, 2011 NMFS published a notice of receipt of an 
application for an LOA in the Federal Register (76 FR 53884) and 
requested comments and information from the interested public for 30 
days. During the 30-day comment period, NMFS received two comments. One 
commenter opposed the project on the grounds that it would cause 
mortality to marine mammals. NMFS notes that the Navy has not requested 
lethal take of marine mammals in its application and, for the reasons 
described in this document, NMFS does not anticipate that any mortality 
will occur as a result of the Navy's activities. Therefore, the 
proposed rule only envisions the authorization of Level A and Level B 
harassment of marine mammals. The other comment, from an environmental 
non-governmental organization, expressed concerns about the geographic 
mitigation proposed in the Navy's DSEIS/SOEIS, focusing particularly on 
the process for identifying proposed offshore biologically important 
areas (OBIAs). NMFS undertook a systematic and scientifically 
supportable process for identifying OBIAs for this proposed rule 
making. This process is summarized in the Mitigation section of this 
proposed rule and detailed in the Navy's DSEIS/SOEIS.
    The Marine Mammal Commission (MMC) also submitted comments to the 
Navy and NMFS. Generally, the MMC agreed that NMFS should propose 
regulations governing the take of marine mammals incidental to 
operation of SURTASS LFA sonar for a third five-year period. However, 
the MMC recommended that the Navy amend its application and related 
DSEIS/SOEIS to: (1) clarify the Navy's take request for marine mammals 
by Level A harassment; and (2) specify the numbers of marine mammals 
that could be taken by Level A and B harassment incidental to operating 
SURTASS LFA sonar, rather than providing only the probabilities of such 
takes. With respect to the first point, NMFS notes that the Navy's 
application specifically requests authorization for Level A harassment 
of

[[Page 847]]

marine mammals incidental to SURTASS LFA sonar operations.
    With respect to the MMC's second point, the percentages given in 
Tables 6 through 27 in the Navy's application are not probabilities, 
but rather indicate the percent of the affected stock for a specific 
marine mammal species. For the Navy's Level A and Level B harassment 
take request, that percentage is then multiplied by the number of 
animals in the relevant species or stock to arrive at an estimated 
number of animals that may be harassed by SURTASS LFA sonar operations. 
The Navy's approach to estimating Level A harassment and Level B 
harassment takes is consistent with the approach used in previous rules 
for SURTASS LFA sonar.
    This proposed rule does not specify the number of marine mammals 
that may be taken in the proposed locations because these are 
determined annually through various inputs such as mission location, 
mission duration, and season of operation. As with the previous two 
rulemakings, this proposed rule analyzes a maximum of 12 percent takes 
by Level B harassment per stock annually that will be taken per stock 
annually, regardless of the number of LFA sonar vessels operating. The 
Navy will use the 12 percent cap (i.e., the maximum percentage of a 
stock that could be taken annually, not the probability of take) to 
guide its mission planning and annual LOA applications. For the annual 
applications for LOAs, the Navy proposes to present both the estimated 
percentage of stock incidentally harassed as well as the estimated 
number of animals that may be potentially harassed by SURTASS LFA 
sonar.

Description of Marine Mammals in the Area of the Specified Activities

    Ninety-four (94) marine mammal species or populations/stocks have 
confirmed or possible occurrence within potential SURTASS LFA 
operational areas in certain areas of the Pacific, Atlantic, and Indian 
Oceans and the Mediterranean Sea. Twelve species of baleen whales 
(mysticetes), 58 species of toothed whales, dolphins, or porpoises 
(odontocetes), and 24 species of seals or sea lions (pinnipeds) could 
be affected by SURTASS LFA sonar operations.
    Fifteen of the 94 marine mammal species are listed as endangered 
and three of the 94 marine mammal species are listed as threatened 
under the Endangered Species Act of 1973 (ESA; 16 U.S.C. 1531 et seq.). 
Marine mammal species under NMFS' jurisdiction listed as endangered 
include: the blue whale (Balaenoptera musculus); fin whale 
(Balaenoptera physalus); sei whale (Balaenoptera borealis); humpback 
whale (Megaptera novaeangliae); bowhead whale (Balaena mysticetus); 
North Atlantic right whale (Eubalaena glacialis); North Pacific right 
whale (Eubalaena japonica); southern right whale (Eubalaena australis); 
gray whale (Eschrichtius robustus); sperm whale (Physeter 
macrocephalus); the Cook Inlet stock of beluga whale (Delphinapterus 
leucas); the Southern Resident population of Killer whale (Orca 
orcinus); the western distinct population segment (DPS) of the Steller 
sea lion (Eumetopias jubatus); Mediterranean monk seal (Monachus 
monachus); and Hawaiian monk seal (Monachus schauinslandi). Marine 
mammal species under NMFS' jurisdiction listed as threatened include: 
the eastern DPS of the Steller sea lion; the Guadalupe fur seal 
(Arctocephalus townsendi) and the southern DPS of the spotted seal 
(Phoca largha). The aforementioned threatened and endangered marine 
mammal species also are depleted under the MMPA.
    In addition, the Hawaiian insular DPS of false killer whale 
(Pseudorca crassidens) is a candidate for proposed listing under the 
ESA. Also, three of the 94 species are considered depleted under the 
MMPA. They are: the western north Atlantic coastal stock of bottlenose 
dolphin (Tursiops truncatus); the northeastern offshore stock of the 
pantropical spotted dolphin (Stenella attenuata); and the eastern stock 
of the spinner dolphin (Stenella longirostris).
    Ringed seals (Phoca hispida), bearded seals (Erignathus barbatus), 
Chinese river dolphins (Lipotes vexillifer) and vaquita (Phocoena 
sinus) do not have stocks designated within potential SURTASS LFA sonar 
operational areas (see Potential SURTASS LFA Operational Areas 
section). The ringed seal is found in the Northern Hemisphere with a 
circumpolar distribution ranging from 35[deg] N to the North Pole. 
Bearded seals have a circumpolar distribution south of 85[deg] N 
latitude, extending south into the southern Bering Sea in the Pacific 
and into Hudson Bay and southern Labrador in the Atlantic. The 
distribution of the Chinese river dolphin is limited to the main 
channel of a river section between the cities of Jingzhou and Jiangyin. 
The vaquita's distribution is restricted to the upper portion of the 
northern Gulf of California, mostly within the Colorado River delta. 
Based on the rare occurrence of these species in the Navy's designated 
operational areas (i.e., outside of Arctic waters or outside of the 
coastal standoff distance of 22 km (13. mi; 11.8 nmi)), the Navy and 
NMFS do not anticipate any take of ringed seals, bearded seals, Chinese 
river dolphins, and vaquita and therefore these species are not 
addressed further in this document.
    The U.S. Fish and Wildlife Service (USFWS) is responsible for 
managing the following marine mammal species: southern sea otter 
(Enhydra lutris), polar bear (Ursus maritimus), walrus (Odobenus 
rosmarus), west African manatee (Trichechus senegalensis), Amazonian 
manatee (Trichechus inunguis), west Indian manatee (Trichechus 
manatus), and dugong (Dugong dugon). None of these species occur in 
geographic areas that would overlap with SURTASS LFA sonar operational 
areas. Therefore, the Navy has determined that routine training and 
testing of SURTASS LFA sonar as well as the use of the system during 
military operations would have no effect on the endangered or 
threatened species or the critical habitat of the ESA-listed species 
under the jurisdiction of the USFWS. These species are not considered 
further in this notice.
    Tables 3 through 21 summarize the abundance, status under the ESA, 
and density estimates of the marine mammals that have confirmed or 
possible occurrence within 19 SURTASS LFA sonar operating areas in the 
Pacific, Indian, and Atlantic Oceans and Mediterranean Sea. The Navy 
states that they selected these 19 areas based on relevance to national 
security interests for this application. Because it is infeasible for 
the Navy to model enough representative sites to cover all potential 
SURTASS LFA sonar operating areas, the Navy provided 19 sites, based on 
the current political climate, as examples of potential operating areas 
in their application.
    Information on how the density and stock/abundance estimates were 
derived for the selected mission sites is in the Navy's application. 
These data are derived from current, published source documentation, 
and provide general area information for each mission area with 
species-specific information on the animals that could occur in that 
area, including estimates for their stock abundance and density. The 
Navy developed the majority of the abundance and density estimates by 
first using estimates from line-transect surveys that occurred in or 
near each of the 19 model sites (e.g., Barlow, 2006). When density 
estimates were not available from a survey in the operating area, the 
Navy extrapolated density estimates from a region with similar 
oceanographic characteristics to that operating area. For example, the 
eastern

[[Page 848]]

tropical Pacific has been extensively surveyed and provides a 
comprehensive understanding of marine mammals in temperate oceanic 
waters (Ferguson and Barlow, 2001, 2003). Further, the Navy pooled 
density estimates for species of the same genus if sufficient data are 
not available to compute a density for individual species or the 
species are difficult to distinguish at sea.

  Table 3--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                     With the East of Japan Operational Area
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Blue whale (Balaenoptera musculus)...  NP......................           9,250       0.0002  EN
Fin whale (Balaenoptera physalus)....  NP......................           9,250       0.0002  EN
Sei whale (Balaenoptera borealis)....  NP......................           8,600       0.0006  EN
Bryde's whale (Balaenoptera edeni)...  WNP.....................          20,501       0.0006  NL
Minke whale (Balaenoptera              WNP ``O'' Stock.........          25,049       0.0022  NL
 acutorostrata).
North Pacific right whale (Eubalaena   WNP.....................             922    < 0.00001  EN
 japonica).
Sperm whale (Physeter macrocephalus).  NP......................         102,112       0.0010  EN
Pygmy sperm whale (Kogia breviceps)    NP......................         350,553       0.0031  NL
 Dwarf sperm whale (Kogia sima).
Baird's beaked whale (Berardius        WNP.....................           8,000       0.0029  NL
 bairdii).
Cuvier's beaked whale (Ziphius         NP......................          90,725       0.0054  NL
 cavirostris).
Ginkgo-toothed beaked whale            NP......................          22,799       0.0005  NL
 (Mesoplodon ginkgodens).
Hubbs beaked whale (Mesoplodon         NP......................          22,799       0.0005  NL
 carhubbsi).
False killer whale (Pseudorca          WNP-Pelagic.............          16,668       0.0036  NL
 crassidens).
Pygmy killer whale (Feresa attenuata)  WNP.....................          30,214       0.0021  NL
Short-finned pilot whale               WNP.....................          53,608       0.0128  NL
 (Globicephala macrorhynchus).
Risso's dolphin (Grampus griseus)....  WNP.....................          83,289       0.0097  NL
Common dolphin (Delphinus delphis)...  WNP.....................       3,286,163       0.0761  NL
Fraser's dolphin (Lagenodelphis        WNP.....................         220,789       0.0040  NL
 hosei).
Bottlenose dolphin (Tursiops           WNP.....................         168,791       0.0171  NL
 truncatus).
Pantropical spotted dolphin (Stenella  WNP.....................         438,064       0.0259  NL
 attenuata).
Striped dolphin (Stenella              WNP.....................         570,038       0.0111  NL
 coeruleoalba).
Spinner dolphin (Stenella              WNP.....................       1,015,059       0.0005  NL
 longirostris).
Pacific white-sided dolphin            WNP.....................         931,000       0.0082  NL
 (Lagenorhynchus obliquidens).
Rough-toothed dolphin (Steno           WNP.....................         145,729       0.0059  NL
 bredanensis).
----------------------------------------------------------------------------------------------------------------
\1\ NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


  Table 4--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                 With the North Philippine Sea Operational Area
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA  Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Bryde's whale........................  WNP.....................          20,501       0.0006  NL
Minke whale..........................  WNP ``O'' Stock.........          25,049       0.0044  NL
North Pacific right whale............  WNP.....................             922    < 0.00001  EN
Sperm whale..........................  NP......................         102,112       0.0028  EN
Pygmy sperm and Dwarf sperm whale....  NP......................         350,553       0.0031  NL
Cuvier's beaked whale................  NP......................          90,725       0.0054  NL
Blainville's beaked whale (Mesoplodon  NP......................           8,032       0.0005  NL
 densirostris).
Ginkgo-toothed beaked whale..........  NP......................          22,799       0.0005  NL
Killer whale (Orca orcinus)..........  NP......................          12,256       0.0004  NL
False killer whale...................  WNP-Pelagic.............          16,668       0.0029  NL
Pygmy killer whale...................  WNP.....................          30,214       0.0021  NL
Melon-headed whale (Peponocephala      WNP.....................          36,770       0.0012  NL
 electra).
Short-finned pilot whale.............  WNP.....................          53,608       0.0153  NL
Risso's dolphin......................  WNP.....................          83,289       0.0106  NL
Common dolphin.......................  WNP.....................       3,286,163       0.0562  NL
Fraser's dolphin.....................  WNP.....................         220,789       0.0040  NL
Bottlenose dolphin...................  WNP.....................         168,791       0.0146  NL
Pantropical spotted dolphin..........  WNP.....................         438,064       0.0137  NL
Striped dolphin......................  WNP.....................         570,038       0.0329  NL
Spinner dolphin......................  WNP.....................       1,015,059       0.0005  NL
Pacific white-sided dolphin..........  WNP.....................         931,000       0.0119  NL
Rough-toothed dolphin................  WNP.....................         145,729       0.0059  NL
----------------------------------------------------------------------------------------------------------------
\1\ NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


[[Page 849]]


  Table 5--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                  With the West Philippine Sea Operational Area
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA  Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Fin whale............................  NP......................           9,250       0.0002  EN
Bryde's whale........................  WNP.....................          20,501       0.0006  NL
Minke whale..........................  WNP ``O'' Stock.........          25,049       0.0033  NL
Humpback whale.......................  WNP.....................           1,107       0.0008  EN
Sperm whale..........................  NP......................         102,112       0.0010  EN
Pygmy sperm and Dwarf sperm whale....  NP......................         350,553       0.0017  NL
Cuvier's beaked whale................  NP......................          90,725       0.0003  NL
Blainville's beaked whale............  NP......................           8,032       0.0005  NL
Ginkgo-toothed beaked whale..........  NP......................          22,799       0.0005  NL
False killer whale...................  WNP-Pelagic.............          16,668       0.0029  NL
Pygmy killer whale...................  WNP.....................          30,214       0.0021  NL
Melon-headed whale...................  WNP.....................          36,770       0.0012  NL
Short-finned pilot whale.............  WNP.....................          53,608       0.0076  NL
Risso's dolphin......................  WNP.....................          83,289       0.0106  NL
Common dolphin.......................  WNP.....................       3,286,163       0.0562  NL
Fraser's dolphin.....................  WNP.....................         220,789       0.0040  NL
Bottlenose dolphin...................  WNP.....................         168,791       0.0146  NL
Pantropical spotted dolphin..........  WNP.....................         438,064       0.0137  NL
Striped dolphin......................  WNP.....................         570,038       0.0164  NL
Spinner dolphin......................  WNP.....................       1,015,059       0.0005  NL
Pacific white-sided dolphin..........  WNP.....................         931,000       0.0245  NL
Rough-toothed dolphin................  WNP.....................         145,729       0.0059  NL
----------------------------------------------------------------------------------------------------------------
\1\ NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


  Table 6--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                     With the Offshore Guam Operational Area
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA  Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Blue whale...........................  ENP.....................           2,842       0.0001  EN
Fin whale............................  ENP.....................           9,250       0.0003  EN
Sei whale............................  NP......................           8,600       0.0003  EN
Bryde's whale........................  WNP.....................          20,501       0.0004  NL
Minke whale..........................  WNP ``O'' Stock.........          25,049       0.0003  NL
Humpback whale.......................  CNP.....................          10,103       0.0069  EN
Sperm whale..........................  NP......................         102,112       0.0012  EN
Pygmy sperm and Dwarf sperm whale....  NP......................         350,553       0.0101  NL
Cuvier's beaked whale................  NP......................          90,725       0.0062  NL
Blainville's beaked whale............  NP......................           8,032       0.0012  NL
Ginkgo-toothed beaked whale..........  NP......................          22,799       0.0005  NL
Longman's beaked whale (Indopacetus    CNP.....................           1,007       0.0004  NL
 pacificus).
Killer whale.........................  CNP.....................             349       0.0001  NL
False killer whale...................  WNP-Pelagic.............          16,668       0.0011  NL
Pygmy killer whale...................  WNP.....................          30,214       0.0001  NL
Melon-headed whale...................  WNP.....................          36,770       0.0043  NL
Short-finned pilot whale.............  WNP.....................          53,608       0.0016  NL
Risso's dolphin......................  WNP.....................          83,289       0.0010  NL
Common dolphin.......................  WNP.....................       3,286,163       0.0021  NL
Fraser's dolphin.....................  CNP.....................          10,226       0.0042  NL
Bottlenose dolphin...................  WNP.....................         168,791       0.0002  NL
Pantropical spotted dolphin..........  WNP.....................         438,064       0.0226  NL
Striped dolphin......................  WNP.....................         570,038       0.0062  NL
Spinner dolphin......................  WNP.....................       1,015,059       0.0031  NL
Rough-toothed dolphin................  WNP.....................         145,729       0.0003  NL
----------------------------------------------------------------------------------------------------------------
\1\ CNP = central north Pacific; ENP = eastern north Pacific; NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


[[Page 850]]


  Table 7--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                     With the Sea of Japan Operational Area
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA  Status\4\
                                                                                  Km\2\ \3\
----------------------------------------------------------------------------------------------------------------
Fin whale............................  NP......................           9,250       0.0009  EN
Bryde's whale........................  WNP.....................          20,501       0.0001  NL
Minke whale..........................  WNP ``O'' Stock.........          25,049       0.0004  NL
Minke whale..........................  WNP ``J'' Stock.........             893       0.0002  NL
North Pacific right whale............  WNP.....................             922    < 0.00001  EN
Gray whale (Eschrichtius robustus)...  WNP.....................             121    < 0.00001  EN \5\
Sperm whale..........................  NP......................         102,112       0.0008  EN
Stejneger's beaked whale (Mesoplodon   NP......................           8,000       0.0014  NL
 stejnegeri).
Baird's beaked whale.................  WNP.....................           8,000       0.0003  NL
Cuvier's beaked whale................  NP......................          90,725       0.0043  NL
Ginkgo-toothed beaked whale..........  NP......................          22,799       0.0005  NL
False killer whale...................  IA-Pelagic..............           9,777       0.0027  NL
Melon-headed whale...................  WNP.....................          36,770      0.00001  NL
Short-finned pilot whale.............  WNP.....................          53,608       0.0014  NL
Risso's dolphin......................  WNP.....................          83,289       0.0073  NL
Common dolphin.......................  WNP.....................       3,286,163       0.0860  NL
Bottlenose dolphin...................  IA......................         105,138       0.0009  NL
Pantropical spotted dolphin..........  WNP.....................         219,032       0.0137  NL
Spinner dolphin......................  WNP.....................       1,015,059      0.00001  NL
Pacific white-sided dolphin..........  WNP.....................         931,000       0.0030  NL
Dall's porpoise (Phocoenoides dalli).  SOJ.....................          76,720       0.0520  NL
----------------------------------------------------------------------------------------------------------------
\1\ IA = Inshore Archipelago; NP = north Pacific; SOJ = Sea of Japan; WNP = western north Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ Only the western Pacific population of gray whale is endangered under the ESA.


  Table 8--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                    With the East China Sea Operational Area
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Fin whale............................  ECS.....................             500       0.0002  EN
Bryde's whale........................  WNP.....................          20,501       0.0006  NL
Minke whale..........................  WNP ``O'' Stock.........          25,049       0.0044  NL
Minke whale..........................  WNP ``J'' Stock.........             893       0.0018  NL
North Pacific right whale............  WNP.....................             922    < 0.00001  EN
Gray whale...........................  WNP.....................             121    < 0.00001  EN \5\
Sperm whale..........................  NP......................         102,112       0.0012  EN
Pygmy sperm and Dwarf sperm whale....  NP......................         350,553       0.0031  NL
Cuvier's beaked whale................  NP......................          90,725       0.0062  NL
Blainville's beaked whale............  NP......................           8,032       0.0012  NL
Ginkgo-toothed beaked whale..........  NP......................          22,799       0.0005  NL
False killer whale...................  IA-Pelagic..............           9,777       0.0011  NL
Pygmy killer whale...................  WNP.....................          30,214       0.0001  NL
Melon-headed whale...................  WNP.....................          36,770       0.0043  NL
Short-finned pilot whale.............  WNP.....................          53,608       0.0016  NL
Risso's dolphin......................  WNP.....................          83,289       0.0106  NL
Common dolphin.......................  WNP.....................       3,286,163       0.0461  NL
Fraser's dolphin.....................  WNP.....................         220,789       0.0040  NL
Bottlenose dolphin...................  IA......................         105,138       0.0146  NL
Pantropical spotted dolphin..........  WNP.....................         219,032       0.0137  NL
Striped dolphin......................  WNP.....................         570,038       0.0164  NL
Spinner dolphin......................  WNP.....................       1,015,059       0.0031  NL
Pacific white-sided dolphin..........  WNP.....................         931,000       0.0028  NL
Rough-toothed dolphin................  WNP.....................         145,729       0.0059  NL
----------------------------------------------------------------------------------------------------------------
\1\ ECS = East China Sea; IA = Inshore Archipelago; NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ Only the western Pacific population of gray whale is endangered under the ESA.


[[Page 851]]


  Table 9--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                    With the South China Sea Operational Area
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Fin whale............................  WNP.....................           9,250       0.0002  EN
Bryde's whale........................  WNP.....................          20,501       0.0006  NL
Minke whale..........................  WNP ``O'' Stock.........          25,049       0.0033  NL
North Pacific right whale............  WNP.....................             922    < 0.00001  EN
Gray whale...........................  WNP.....................             121     < 0.0001  EN \5\
Sperm whale..........................  NP......................         102,112       0.0012  EN
Pygmy sperm and Dwarf sperm whale....  NP......................         350,553       0.0017  NL
Cuvier's beaked whale................  NP......................          90,725       0.0003  NL
Blainville's beaked whale............  NP......................           8,032       0.0005  NL
Ginkgo-toothed beaked whale..........  NP......................          22,799       0.0005  NL
False killer whale...................  IA-Pelagic..............           9,777       0.0011  NL
Pygmy killer whale...................  WNP.....................          30,214       0.0001  NL
Melon-headed whale...................  WNP.....................          36,770       0.0043  NL
Short-finned pilot whale.............  WNP.....................          53,608       0.0016  NL
Risso's dolphin......................  WNP.....................          83,289       0.0106  NL
Common dolphin.......................  WNP.....................       3,286,163       0.0461  NL
Fraser's dolphin.....................  WNP.....................         220,789       0.0040  NL
Bottlenose dolphin...................  IA......................         105,138       0.0146  NL
Pantropical spotted dolphin..........  WNP.....................         219,032       0.0137  NL
Striped dolphin......................  WNP.....................         570,038       0.0164  NL
Spinner dolphin......................  WNP.....................       1,015,059       0.3140  NL
Rough-toothed dolphin................  WNP.....................         145,729       0.0040  NL
----------------------------------------------------------------------------------------------------------------
\1\ IA = Inshore Archipelago; NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ Only the western Pacific population of gray whale is endangered under the ESA.


 Table 10--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                         With the Operational Area Offshore Japan (25[deg] to 40[deg] N)
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA  Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Blue whale...........................  NP......................           9,250       0.0003  EN
Fin whale............................  NP......................           9,250       0.0001  EN
Sei whale............................  NP......................          37,000       0.0003  EN
Bryde's whale........................  WNP.....................          20,501       0.0004  NL
Minke whale..........................  WNP ``O'' Stock.........          25,049       0.0003  NL
Sperm whale..........................  NP......................         102,112       0.0003  EN
Pygmy sperm and Dwarf sperm whale....  NP......................         350,553       0.0049  NL
Baird's beaked whale.................  WNP.....................           8,000       0.0001  NL
Cuvier's beaked whale................  NP......................          90,725       0.0017  NL
Mesoplodon spp.......................  NP......................          22,799       0.0005  NL
False killer whale...................  WNP-Pelagic.............          16,668       0.0036  NL
Pygmy killer whale...................  WNP.....................          30,214       0.0001  NL
Melon-headed whale...................  WNP.....................          36,770       0.0012  NL
Short-finned pilot whale.............  WNP.....................          53,608       0.0001  NL
Risso's dolphin......................  WNP.....................          83,289       0.0010  NL
Common dolphin.......................  WNP.....................       3,286,163       0.0863  NL
Bottlenose dolphin...................  WNP.....................         168,791       0.0005  NL
Pantropical spotted dolphin..........  WNP.....................         438,064       0.0181  NL
Striped dolphin......................  WNP.....................         570,038       0.0500  NL
Spinner dolphin......................  WNP.....................       1,015,059      0.00001  NL
Pacific white-sided dolphin..........  WNP.....................          67,769       0.0048  NL
Rough-toothed dolphin................  WNP.....................         145,729       0.0003  NL
Hawaiian monk seal...................  Hawaii..................           1,129    < 0.00001  EN
(Monachus schauinslandi).............
----------------------------------------------------------------------------------------------------------------
\1\ NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


[[Page 852]]


 Table 11--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                         With the Operational Area Offshore Japan (10[deg] to 25[deg] N)
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA  Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Bryde's whale........................  WNP.....................          20,501       0.0004  NL
Sperm whale..........................  NP......................         102,112       0.0004  EN
Pygmy sperm and Dwarf sperm whale....  NP......................         350,553       0.0009  NL
Cuvier's beaked whale................  NP......................          90,725       0.0017  NL
False killer whale...................  WNP-Pelagic.............          16,668       0.0021  NL
Melon-headed whale...................  WNP.....................          36,770       0.0012  NL
Short-finned pilot whale.............  WNP.....................          53,608       0.0009  NL
Risso's dolphin......................  WNP.....................          83,289       0.0026  NL
Common dolphin.......................  WNP.....................       3,286,163       0.0863  NL
Bottlenose dolphin...................  WNP.....................         168,791       0.0007  NL
Pantropical spotted dolphin..........  WNP.....................         438,064       0.0226  NL
Striped dolphin......................  WNP.....................         570,038       0.0110  NL
Spinner dolphin......................  WNP.....................       1,015,059       0.0031  NL
Rough-toothed dolphin................  WNP.....................         145,729       0.0003  NL
----------------------------------------------------------------------------------------------------------------
\1\ NP = north Pacific; WNP = western north Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 12--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                    With the Northern Hawaii Operational Area
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA  Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Blue whale...........................  WNP.....................           1,548       0.0002  EN
Fin whale............................  Hawaii..................           2,099       0.0007  EN
Bryde's whale........................  Hawaii..................             469       0.0002  NL
Minke whale..........................  WNP.....................          25,000       0.0002  NL
Humpback whale.......................  Hawaii..................          10,103     < 0.0001  EN
Sperm whale..........................  CNP.....................           6,919       0.0028  EN
Pygmy sperm and Dwarf sperm whale....  Hawaii..................          24,657       0.0101  NL
Cuvier's beaked whale................  Hawaii..................          15,242       0.0062  NL
Blainville's beaked whale............  Hawaii..................           2,872       0.0012  NL
Longman's beaked whale...............  Hawaii..................           1,007       0.0004  NL
Killer whale.........................  Hawaii..................             349       0.0001  NL
False killer whale...................  Hawaii-Pelagic..........             484       0.0002  NL
Pygmy killer whale...................  Hawaii..................             956       0.0004  NL
Melon-headed whale...................  Hawaii..................           2,950       0.0012  NL
Short-finned pilot whale.............  Hawaii..................           8,870       0.0036  NL
Risso's dolphin......................  Hawaii..................           2,372       0.0010  NL
Fraser's dolphin.....................  Hawaii..................          10,226       0.0042  NL
Bottlenose dolphin...................  Hawaii..................           3,215       0.0013  NL
Pantropical spotted dolphin..........  Hawaii..................           8,978       0.0037  NL
Striped dolphin......................  Hawaii..................          13,143       0.0054  NL
Spinner dolphin......................  Hawaii..................           3,351       0.0014  NL
Rough-toothed dolphin................  Hawaii..................           8,709       0.0036  NL
Hawaiian monk seal...................  Hawaii..................           1,129     < 0.0001  EN
----------------------------------------------------------------------------------------------------------------
\1\ CNP = central north Pacific; WNP = western north Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 13--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                                    With the Southern Hawaii Operational Area
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Blue whale...........................  WNP.....................           1,548       0.0002  EN
Fin whale............................  Hawaii..................           2,099       0.0007  EN
Bryde's whale........................  Hawaii..................             469       0.0002  NL
Minke whale..........................  Hawaii..................          25,000       0.0002  NL
Humpback whale.......................  Hawaii..................          10,103       0.0008  EN
Sperm whale..........................  CNP.....................           6,919       0.0028  EN
Pygmy sperm and Dwarf sperm whale....  Hawaii..................          24,657       0.0101  NL

[[Page 853]]

 
Cuvier's beaked whale................  Hawaii..................          15,242       0.0062  NL
Blainville's beaked whale............  Hawaii..................           2,872       0.0012  NL
Longman's beaked whale...............  Hawaii..................           1,007       0.0004  NL
Killer whale.........................  Hawaii..................             349       0.0001  NL
False killer whale...................  Hawaii-Pelagic..........             484       0.0002  NL
Pygmy killer whale...................  Hawaii..................             956       0.0004  NL
Melon-headed whale...................  Hawaii..................           2,950       0.0012  NL
Short-finned pilot whale.............  Hawaii..................           8,870       0.0036  NL
Risso's dolphin......................  Hawaii..................           2,372       0.0010  NL
Fraser's dolphin.....................  Hawaii..................          10,226       0.0042  NL
Bottlenose dolphin...................  Hawaii..................           3,215       0.0013  NL
Pantropical spotted dolphin..........  Hawaii..................           8,978       0.0037  NL
Striped dolphin......................  Hawaii..................          13,143       0.0054  NL
Spinner dolphin......................  Hawaii..................           3,351       0.0014  NL
Rough-toothed dolphin................  Hawaii..................           8,709       0.0036  NL
Hawaiian monk seal...................  Hawaii..................           1,129     < 0.0001  EN
----------------------------------------------------------------------------------------------------------------
\1\ CNP = central north Pacific; WNP = western north Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 14--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                      With the Operational Area Offshore Southern California (SOCAL OPAREA)
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Blue whale...........................  ENP.....................           2,842       0.0014  EN
Fin whale............................  CA/OR/WA................           2,099       0.0018  EN
Sei whale............................  ENP.....................              98       0.0001  EN
Bryde's whale........................  ENP.....................          13,000      0.00001  NL
Northern minke whale.................  CA/OR/WA................             823       0.0007  NL
Humpback whale.......................  CA/OR/WA................             942       0.0008  EN
Gray whale...........................  ENP.....................          18,813        0.051  EN \5\
Sperm whale..........................  CA/OR/WA................           1,934       0.0017  EN
Pygmy sperm whale....................  CA/OR/WA................           1,237       0.0011  NL
Stejneger's beaked whale.............  CA/OR/WA................           1,177       0.0010  NL
Baird's beaked whale.................  CA/OR/WA................           1,005       0.0009  NL
Cuvier's beaked whale................  CA/OR/WA................           4,342       0.0038  NL
Blainville's beaked whale............  CA/OR/WA................           1,177       0.0010  NL
Ginkgo-toothed beaked whale..........  CA/OR/WA................           1,177       0.0010  NL
Hubbs beaked whale...................  CA/OR/WA................           1,177       0.0010  NL
Longman's beaked whale...............  Hawaii..................           1,177       0.0010  NL
Perrin's beaked whale (Mesoplodon      CA/OR/WA................           1,177       0.0010  NL
 perrini).
Pygmy beaked whale (Mesoplodon         CA/OR/WA................           1,177       0.0010  NL
 peruvianus).
Killer whale (offshore)..............  ENP.....................             810       0.0007  NL
Short-finned pilot whale.............  CA/OR/WA................             350       0.0003  NL
Risso's dolphin......................  CA/OR/WA................          11,910       0.0105  NL
Long-beaked common dolphin (Delphinus  CA/OR/WA................          21,902       0.0192  NL
 capensis).
Short-beaked common dolphin            CA/OR/WA................         352,069       0.3094  NL
 (Delphinus delphis).
Bottlenose dolphin (offshore)........  CA/OR/WA................           2,026       0.0018  NL
Striped dolphin......................  CA/OR/WA................          18,976       0.0167  NL
Pacific white-sided dolphin..........  CA/OR/WA................          23,817       0.0209  NL
Northern right whale dolphin           CA/OR/WA................          11,097       0.0098  NL
 (Lissodelphis borealis).
Dall's porpoise......................  CA/OR/WA................          85,955       0.0753  NL
Guadalupe fur seal (Arctocephalus      Mexico..................           7,408        0.007  NL
 townsendi).
Northern fur seal (Callorhinus         SMI.....................           9,424            0  NL
 ursinus).
California sea lion (Zalophus          California..............         238,000         0.54  NL
 californianus).
California sea lion..................  California..............         238,000            0  NL
Harbor seal (Phoca vitulina).........  California..............          34,233       0.0095  NL
Northern elephant seal (Mirounga       CA-Breeding.............         124,000       0.0045  NL
 angustirostris).
Northern elephant seal...............  CA-Breeding.............         124,000            0  NL
----------------------------------------------------------------------------------------------------------------
\1\ CA/OR/WA = California, Oregon, and Washington; ENP = eastern north Pacific; SMI = San Miguel Island.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.
\5\ Only the western Pacific population of gray whale is endangered under the ESA.


[[Page 854]]


 Table 15--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                    With the Northwestern Atlantic Operational Area Off Florida (JAX OPAREA)
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA  Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Humpback whale.......................  WNA.....................          11,570       0.0006  EN
North Atlantic right whale (on shelf)  WNA.....................             438       0.0012  EN
Sperm whale (on shelf)...............  WNA.....................           4,804            0  EN
Sperm whale (off shelf)..............  WNA.....................           4,804       0.0005  EN
Pygmy sperm and Dwarf sperm whale....  WNA.....................             580       0.0010  NL
Beaked whales (on shelf).............  WNA.....................           3,513            0  NL
Beaked whales (off shelf)............  WNA.....................           3,513       0.0006  NL
Cuvier's beaked whale................  WNA.....................           3,513       0.0006  NL
Blainville's beaked whale............  WNA.....................           3,513       0.0006  NL
Gervais' beaked whale (Mesoplodon      WNA.....................           3,513       0.0006  NL
 europaeus).
Sowerby's beaked whale (Mesoplodon     WNA.....................           3,513       0.0006  NL
 bidens).
True's beaked whale (Mesoplodon        WNA.....................           3,513       0.0006  NL
 mirus).
Short-finned pilot whale (on shelf)..  WNA.....................          31,139      0.00004  NL
Short-finned pilot whale (off shelf).  WNA.....................          31,139       0.0271  NL
Risso's dolphin (on shelf)...........  WNA.....................          20,479       0.0009  NL
Risso's dolphin (off shelf)..........  WNA.....................          20,479       0.0181  NL
Common dolphin.......................  WNA.....................         120,743      0.00002  NL
Bottlenose dolphin (on shelf)........  WNA.....................          81,588       0.2132  NL
Bottlenose dolphin (off shelf).......  WNA.....................          81,588       0.1163  NL
Pantropical spotted dolphin..........  WNA.....................          12,747       0.0223  NL
Striped dolphin......................  WNA.....................          94,462      0.00003  NL
Atlantic spotted dolphin (on shelf)    WNA.....................          50,978       0.4435  NL
 (Stenella frontalis).
Atlantic spotted dolphin (off shelf).  WNA.....................          50,978       0.0041  NL
Clymene dolphin (Stenella clymene)...  WNA.....................           6,086       0.0106  NL
Rough-toothed dolphin................  WNA.....................             274       0.0005  NL
----------------------------------------------------------------------------------------------------------------
\1\ WNA = western north Atlantic.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 16--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                 With the Operational Area in the Northeastern Atlantic Off the United Kingdom.
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Blue whale...........................  ENA.....................             100      0.00001  EN
Fin whale............................  ENA.....................          10,369       0.0031  EN
Sei whale............................  ENA.....................          14,152       0.0113  EN
Northern minke whale.................  ENA.....................         107,205       0.0068  NL
Humpback whale.......................  ENA.....................           4,695       0.0019  EN
Sperm whale..........................  ENA.....................           6,375       0.0049  EN
Pygmy sperm and Dwarf sperm whale....  ENA.....................             580       0.0001  NL
Cuvier's beaked whale................  ENA.....................           3,513       0.0013  NL
Blainville's beaked whale............  ENA.....................           3,513       0.0013  NL
Sowerby's beaked whale...............  ENA.....................           3,513       0.0013  NL
Northern bottlenose whale (Hyperodon   ENA.....................           5,827       0.0003  NL
 ampullatus).
Killer whale.........................  ENA.....................           6,618       0.0001  NL
False killer whale...................  ENA.....................             484       0.0001  NL
Long-finned pilot whale (Globicephala  ENA.....................         778,000       0.0121  NL
 melas).
Risso's dolphin......................  ENA.....................          20,479       0.0063  NL
Common dolphin.......................  ENA.....................         273,150        0.238  NL
Bottlenose dolphin...................  ENA.....................          81,588       0.0094  NL
Striped dolphin......................  ENA.....................          94,462       0.0765  NL
Atlantic white-sided dolphin           ENA.....................          11,760       0.0027  NL
 (Lagenorhynchus acutus).
White-beaked dolphin (Lagenorhynchus   ENA.....................          11,760       0.0027  NL
 albirostris).
Harbor porpoise (Phocoena phocoena)..  ENA.....................         341,366       0.2299  NL
Harbor seal (Phoca vitulina).........  Ireland/Scotland........          23,500       0.0230  NL
Gray seal (Halichoerus grypus).......  ENA.....................         113,300        0.027  NL
----------------------------------------------------------------------------------------------------------------
\1\ ENA = eastern north Atlantic.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


[[Page 855]]


 Table 17--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                 With the Operational Area in the Western Mediterranean Sea and the Ligurian Sea
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (Animals/     ESA Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Fin whale............................  MED.....................           3,583        0.004  EN
Sperm whale..........................  WMED....................           6,375       0.0049  EN
Cuvier's beaked whale................  ENA.....................           3,513       0.0013  NL
Long-finned pilot whale..............  ENA.....................         778,000       0.0121  NL
Risso's dolphin......................  WMED....................           5,320       0.0075  NL
Common dolphin.......................  WMED....................          19,428       0.0144  NL
Bottlenose dolphin...................  WMED....................          23,304        0.041  NL
Striped dolphin......................  WMED....................         117,880         0.24  NL
----------------------------------------------------------------------------------------------------------------
\1\ ENA = eastern north Atlantic; MED = Mediterranean; WMED = western Mediterranean.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 18--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                              With the Operational Area in the Northern Arabian Sea
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Bryde's whale........................  IND.....................           9,176       0.0001  NL
Humpback whale.......................  XAR.....................             200       0.0004  EN
Sperm whale..........................  IND.....................          24,446       0.0125  EN
Dwarf sperm whale....................  IND.....................          10,541       0.0145  NL
Cuvier's beaked whale................  IND.....................          27,272       0.0001  NL
Blainville's beaked whale............  IND.....................          16,867       0.0016  NL
Ginkgo-toothed beaked whale..........  IND.....................          16,867       0.0016  NL
Longman's beaked whale...............  IND.....................          16,867       0.0016  NL
False killer whale (pelagic).........  IND.....................         144,188       0.0003  NL
Pygmy killer whale...................  IND.....................          22,029       0.0026  NL
Melon-headed whale...................  IND.....................          64,600       0.0661  NL
Short-finned pilot whale.............  IND.....................         268,751       0.0034  NL
Risso's dolphin......................  IND.....................         452,125       0.0125  NL
Common dolphin.......................  IND.....................       1,819,882       0.0265  NL
Bottlenose dolphin...................  IND.....................         785,585       0.0164  NL
Pantropical spotted dolphin..........  IND.....................         736,575       0.0127  NL
Striped dolphin......................  IND.....................         674,578       0.0706  NL
Spinner dolphin......................  IND.....................         634,108         0.01  NL
Rough-toothed dolphin................  IND.....................         156,690       0.0081  NL
----------------------------------------------------------------------------------------------------------------
\1\ IND = Indian Ocean; XAR = Stock X Arabian Sea.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 19--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                            With the Operational Area in the Andaman Sea Off Myanmar
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Bryde's whale........................  IND.....................           9,176       0.0001  NL
Sperm whale..........................  IND.....................          24,446       0.0125  EN
Dwarf sperm whale....................  IND.....................          10,541       0.0145  NL
Cuvier's beaked whale................  IND.....................          27,272       0.0001  NL
Blainville's beaked whale............  IND.....................          16,867       0.0016  NL
Ginkgo-toothed beaked whale..........  IND.....................          16,867       0.0016  NL
Longman's beaked whale...............  IND.....................          16,867       0.0016  NL
Killer whale.........................  IND.....................          12,593       0.0001  NL
False killer whale (pelagic).........  IND.....................         144,188       0.0003  NL
Pygmy killer whale...................  IND.....................          22,029       0.0026  NL
Melon-headed whale...................  IND.....................          64,600       0.0661  NL
Short-finned pilot whale.............  IND.....................         268,751       0.0034  NL
Risso's dolphin......................  IND.....................         452,125       0.0125  NL
Common dolphin.......................  IND.....................       1,819,882       0.0265  NL
Bottlenose dolphin...................  IND.....................         785,585       0.0164  NL
Pantropical spotted dolphin..........  IND.....................         736,575       0.0127  NL
Striped dolphin......................  IND.....................         674,578       0.0706  NL

[[Page 856]]

 
Spinner dolphin......................  IND.....................         634,108         0.01  NL
Rough-toothed dolphin................  IND.....................         156,690       0.0081  NL
----------------------------------------------------------------------------------------------------------------
\1\ IND = Indian Ocean.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 20--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                             With the Panama Canal Operational Area (West Approach)
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Blue whale...........................  ENP.....................           2,842       0.0001  EN
Bryde's whale........................  ETP.....................          13,000       0.0003  NL
Humpback whale.......................  ENP.....................           1,391       0.0004  EN
Sperm whale..........................  ETP.....................          22,700       0.0047  EN
Dwarf sperm whale....................  ETP.....................          11,200       0.0145  NL
Cuvier's beaked whale................  ETP.....................          20,000       0.0025  NL
Blainville's beaked whale............  ETP.....................          25,300       0.0013  NL
Ginkgo-toothed beaked whale..........  ETP.....................          25,300       0.0016  NL
Longman's beaked whale...............  ETP.....................          25,300       0.0003  NL
Pygmy beaked whale (Mesoplodon         ETP.....................          25,300       0.0016  NL
 peruvianus).
Killer whale.........................  ETP.....................           8,500       0.0002  NL
False killer whale (pelagic).........  ETP.....................          39,800       0.0004  NL
Pygmy killer whale...................  ETP.....................          38,900       0.0014  NL
Melon-headed whale...................  ETP.....................          45,400       0.0174  NL
Short-finned pilot whale.............  ETP.....................         160,200       0.0058  NL
Risso's dolphin......................  ETP.....................         110,457       0.0161  NL
Common dolphin.......................  ETP.....................       3,127,203        0.049  NL
Fraser's dolphin.....................  ETP.....................         289,300        0.001  NL
Bottlenose dolphin...................  ETP.....................         335,834       0.0157  NL
Pantropical spotted dolphin..........  NEOP....................         640,000       0.0669  NL
Striped dolphin......................  ETP.....................         964,362       0.1199  NL
Spinner dolphin......................  Eastern.................         450,000        0.007  NL
Rough-toothed dolphin................  ETP.....................         107,633       0.0146  NL
----------------------------------------------------------------------------------------------------------------
\1\ ETP = eastern tropical Pacific; NEOP = northeastern offshore Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.


 Table 21--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated
                         With the Operational Area Off the Northeastern Australian Coast
----------------------------------------------------------------------------------------------------------------
                                                                                   Density
               Species                      Stock name \1\        Abundance \2\   (animals/     ESA Status \4\
                                                                                  Km\2\) \3\
----------------------------------------------------------------------------------------------------------------
Blue whale...........................  WSP.....................           9,250       0.0002  EN
Fin whale............................  WSP.....................           9,250       0.0002  EN
Bryde's whale........................  WSP.....................          22,000       0.0006  NL
Northern minke whale.................  WSP.....................          25,000       0.0044  EN
Humpback whale.......................  GVEA....................           3,500       0.0143  EN
Sperm whale..........................  WSP.....................         102,112       0.0029  EN
Pygmy sperm and Dwarf sperm whale....  WSP.....................         350,553       0.0031  NL
Cuvier's beaked whale................  WSP.....................          90,725       0.0054  NL
Blainville's beaked whale............  WSP.....................           8,032       0.0005  NL
Arnoux's beaked whale (Berardius       WSP.....................          22,799       0.0005  NL
 arnuxii).
Ginkgo-toothed beaked whale..........  WSP.....................          22,799       0.0005  NL
Longman's beaked whale...............  WSP.....................          22,799       0.0005  NL
Southern bottlenose whale (Hyperodon   WSP.....................          22,799       0.0005  NL
 planifrons).
Killer whale.........................  WSP.....................          12,256       0.0004  NL
False killer whale (pelagic).........  WSP.....................          16,668       0.0029  NL
Pygmy killer whale...................  WSP.....................          30,214       0.0021  NL
Melon-headed whale...................  WSP.....................          36,770       0.0012  NL
Globicephala spp.....................  WSP.....................          53,608       0.0153  NL
Risso's dolphin......................  WSP.....................          83,289       0.0106  NL

[[Page 857]]

 
Common dolphin.......................  WSP.....................       3,286,163       0.0562  NL
Fraser's dolphin.....................  WSP.....................         220,789        0.004  NL
Bottlenose dolphin...................  WSP.....................         168,791       0.0146  NL
Pantropical spotted dolphin..........  WSP.....................         438,064       0.0137  NL
Striped dolphin......................  WSP.....................         570,038       0.0329  NL
Spinner dolphin......................  WSP.....................       1,015,059       0.0005  NL
Dusky dolphin (Lagenorhynchus          WSP.....................          12,626       0.0002  NL
 obscurus).
Rough-toothed dolphin................  WSP.....................         145,729       0.0059  NL
----------------------------------------------------------------------------------------------------------------
\1\ GVEA = group V east Australia; WSP = western south Pacific.
\2\ Refer to Table 5 of the Navy's application for literature references associated with abundance estimates
  presented in this table.
\3\ Refer to Table 5 of the Navy's application for literature references associated with density estimates
  presented in this table.
\4\ ESA Status: EN = Endangered; T = Threatened; NL = Not Listed.

    The Navy provides detailed descriptions of the distribution, 
abundance, diving behavior, life history, and hearing vocalization 
information for each affected marine mammal species with confirmed or 
possible occurrence within SURTASS LFA sonar operational areas in 
section 4 (pages 38-97) of the application, which is available online 
at http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications).
    Although not repeated in this document, NMFS has reviewed these 
data, determined them to be the best available scientific information 
for the purposes of the proposed rulemaking, and considers this 
information part of the administrative record for this action. 
Additional information is available in NMFS' Marine Mammal Stock 
Assessment Reports, which may be viewed at http://www.nmfs.noaa.gov/pr/sars/species.htm. Also, NMFS refers the public to Table 5 (page 37) of 
the Navy's application for literature references associated with 
abundance and density estimates presented in these tables.

Brief Background on Sound, Marine Mammal Hearing, and Vocalization

Acoustic Source Specifications

Metrics Used in This Document

    This section includes a brief explanation of the sound measurements 
frequently used in the discussions of acoustic effects in this 
document. Sound pressure is the sound force per unit area and is 
usually measured in micropascals ([mu]Pa), where 1 Pascal (Pa) is the 
pressure resulting from a force of one newton exerted over an area of 
one square meter. Sound pressure level (SPL) is expressed as the ratio 
of a measured sound pressure and a reference level. The commonly used 
reference pressure level in underwater acoustics is 1 [mu]Pa at 1 m, 
and the units for SPLs are decibels (dB) re: 1 [mu]Pa at 1 m. SPL (in 
dB) = 20 log (pressure/reference pressure). SPL is an instantaneous 
measurement and can be expressed as the peak, the peak-peak (p-p), or 
the root mean square (rms). Root mean square, 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 document refer to the 
root mean square unless otherwise noted. SPL does not take the duration 
of a sound into account.

SPL and the Single Ping Equivalent (SPE)

    To model potential impacts to marine animals from exposure to 
SURTASS LFA sonar sound, the Navy has developed a methodology to 
estimate the total exposure of modeled animals exposed to multiple 
pings over an extended period of time. The Navy's acoustic model 
analyzes the following components: (1) The LFA sonar source modeled as 
a point source, with an effective source level (SL) in dB re: 1 [mu]Pa 
at 1 m (SPL); (2) a 60-sec duration signal; and (3) a beam pattern that 
is correct for the number and spacing of the individual projectors 
(source elements). This source model, when combined with the three-
dimensional transmission loss (TL) field generated by the Parabolic 
Equation (PE) acoustic propagation model, defines the received level 
(RL) (in SPL) sound field surrounding the source for a 60-sec LFA sonar 
signal. To estimate the total exposure of animals exposed to multiple 
pings, the Navy models the RLs for each modeled location and any 
computer-simulated marine mammals (also called animats) within the 
location, records the exposure history of each animat, and generates a 
single ping equivalent (SPE) value. Thus, the Navy can model the 
SURTASS LFA sound field, providing a four-dimensional (position and 
time) representation of a sound pressure field within the marine 
environment and estimates of an animal's exposure to sound.
    Figure 2 shows the Navy calculation that converts SPL values to SPE 
values in order to estimate impacts to marine mammals from SURTASS LFA 
sonar transmissions. For a more detailed explanation of the SPE 
calculations, NMFS refers the public to Appendix C of the Navy's 2011 
DSEIS/SOEIS.

[[Page 858]]

[GRAPHIC] [TIFF OMITTED] TP06JA12.001

Underwater Sound

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

Marine Mammal Hearing

    Cetaceans have an auditory anatomy that follows the basic mammalian 
pattern, with some changes to adapt to the demands of hearing in the 
sea. The typical mammalian ear is divided into an outer ear, middle 
ear, and inner ear. The outer ear is separated from the inner ear by a 
tympanic membrane, or eardrum. In terrestrial mammals, the outer ear, 
eardrum, and middle ear transmit airborne sound to the inner ear, where 
the sound waves are propagated through the cochlear fluid. Since the 
impedance of water (i.e., the product of density and sound speed) is 
close to that of the tissues of a cetacean, the outer ear is not 
required to transduce sound energy as it does when sound waves travel 
from air to fluid (inner ear). Sound waves traveling through the inner 
ear cause the basilar membrane to vibrate. Specialized cells, called 
hair cells, respond to the vibration and produce nerve pulses that are 
transmitted to the central nervous system. Acoustic energy causes the 
basilar membrane in the cochlea to vibrate. Sensory cells at different 
positions along the basilar membrane are excited by different 
frequencies of sound (Pickles, 1998).
    When considering the influence of various kinds of sound on the 
marine environment, it is necessary to understand that different kinds 
of marine life are sensitive to different frequencies of sound. Based 
on available behavioral data, audiograms derived using auditory evoked 
potential (AEP) techniques, anatomical modeling, and other data, 
Southall et al. (2007) designated ``functional hearing groups'' for 
marine mammals and estimated the lower and upper frequencies of 
functional hearing (i.e., the frequencies that the species can actually 
hear) of these groups. The functional groups and the associated 
frequencies are described here (though animals are less sensitive to 
sounds at the outer edge of their functional range and most sensitive 
to sounds of frequencies within a smaller range somewhere in the middle 
of their functional hearing range):
     Low frequency (LF) cetaceans (13 species of mysticetes): 
Southall et al. (2007) estimates that functional hearing occurs between 
approximately seven Hz and 22 kHz;
     Mid-frequency (MF) cetaceans (32 species of dolphins, six 
species of larger toothed whales, and 19 species of beaked and 
bottlenose whales): Southall et al. (2007) estimates that functional 
hearing occurs between approximately 150 Hz and 160 kHz;
     High frequency (HF) cetaceans (eight species of true 
porpoises, six species of river dolphins, Kogia, the franciscana, and 
four species of cephalorhynchids): Southall et al. (2007) estimates 
that functional hearing occurs between approximately 200 Hz and 180 
kHz.
     Pinnipeds in Water: Southall et al. (2007) estimates that 
functional hearing occurs between approximately 75 Hz and 75 kHz, with 
the greatest sensitivity between approximately 700 Hz and 20 kHz.

Marine Mammal Functional Hearing Groups and LFA Sonar

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

[[Page 859]]

Marine Mammal Vocalization

    Marine mammal vocalizations often extend both above (higher than 20 
kHz) and below (lower than 20 Hz) the range of human hearing (National 
Research Council, 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. Thus, the ears of small toothed whales are optimized for 
receiving high-frequency sound, while baleen whale inner ears are best 
suited for low frequencies, including to infrasonic frequencies 
(Ketten, 1992; 1997; 1998).
    Baleen whale (i.e., mysticete) vocalizations are composed primarily 
of frequencies below one kHz, and some contain fundamental frequencies 
as low as 16 Hz (Watkins et al., 1987; Richardson et al., 1995; Rivers, 
1997; Moore et al., 1998; Stafford et al., 1999; Wartzok and Ketten, 
1999) but can be as high as 24 kHz (humpback whale; Au et al., 2006). 
Clark and Ellison (2004) suggested that baleen whales use low frequency 
sounds not only for long-range communication, but also as a simple form 
of echo ranging, using echoes to navigate and orient relative to 
physical features of the ocean. Information on auditory function in 
mysticetes is 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 [mu]Pa at 1 m. Low-frequency vocalizations made by 
baleen whales and their corresponding auditory anatomy suggest that 
they have good low-frequency hearing (Ketten, 2000), although specific 
data on sensitivity, frequency or intensity discrimination, or 
localization abilities are lacking. Marine mammals, like all mammals, 
have typical U-shaped audiograms that begin with relatively low 
sensitivity (high threshold) at some specified low frequency with 
increased sensitivity (low threshold) to a species-specific optimum 
followed by a generally steep rise at higher frequencies (high 
threshold) (Fay, 1988).
    Toothed whales (i.e., odontocetes) produce a wide variety of 
sounds, which include species-specific broadband ``clicks'' with peak 
energy between 10 and 200 kHz, individually variable ``burst pulse'' 
click trains, and constant frequency or frequency-modulated (FM) 
whistles ranging from 4 to 16 kHz (Wartzok and Ketten, 1999). The 
general consensus is that the tonal vocalizations (whistles) produced 
by toothed whales play an important role in maintaining contact between 
dispersed individuals, while broadband clicks are used during 
echolocation (Wartzok and Ketten, 1999). Burst pulses have also been 
strongly implicated in communication, with some scientists suggesting 
that they play an important role in agonistic encounters (McCowan and 
Reiss, 1995), while others have proposed that they represent 
``emotive'' signals in a broader sense, possibly representing graded 
communication signals (Herzing, 1996). Sperm whales, however, are known 
to produce only clicks, which are used for both communication and 
echolocation (Whitehead, 2003). Most of the energy of toothed whales 
social vocalizations is concentrated near 10 kHz, with source levels 
for whistles as high as 100-180 dB re 1 [mu]Pa at 1 m (Richardson et 
al., 1995). No odontocete has been shown audiometrically to have acute 
hearing (less than 80 dB re 1 [mu]Pa at 1 m) below 500 Hz (DoN, 2001; 
Ketten, 1998). Sperm whales produce clicks, which may be used to 
echolocate (Mullins et al., 1988), with a frequency range from less 
than 100 Hz to 30 kHz and source levels up to 230 dB re 1 [mu]Pa at 1 m 
or greater (Mohl et al., 2000).

Brief Background on the Navy's Assessment of the Potential Impacts on 
Marine Mammals

    Acoustic Modeling Scenarios. The Navy based their analysis of 
potential impacts on marine mammals from SURTASS LFA sonar on 
literature review, the Navy's Low Frequency Sound Scientific Research 
Program (LFS SRP), and a comprehensive program of underwater acoustical 
modeling.
    To assess the potential impacts on marine mammals by the SURTASS 
LFA sonar source operating at a given site, the Navy must predict the 
sound field that a given marine mammal species could be exposed to over 
time. This is a multi-part process involving: (1) The ability to 
measure or estimate an animal's location in space and time; (2) The 
ability to measure or estimate the three-dimensional sound field at 
these times and locations; (3) The integration of these two data sets 
into the Acoustic Integration Model (AIM) to estimate the total 
acoustic exposure for each animal in the modeled population; and (4) 
Converting the resultant cumulative exposures (within the post-AIM 
analysis) for a modeled population into an estimate of the risk of a 
significant disturbance of a biologically important behavior (i.e., a 
take estimate for Level B harassment of marine mammals based upon an 
estimated percentage of each stock affected by SURTASS LFA sonar 
operations) or an assessment of risk in terms of injury of marine 
mammals (i.e., a take estimate for Level A harassment of marine mammals 
based on a cumulative exposure of greater than or equal to 180-dB SPE). 
In the post-AIM analysis, as mentioned in number (4), the Navy 
developed a relationship for converting the resultant cumulative 
exposures for a modeled population into an estimate of the risk to the 
entire population of a significant disruption of a biologically 
important behavior and of injury. This process assessed risk in 
relation to received level (RL) and repeated exposure. The Navy's risk 
continuum is based on the assumption that the threshold of risk is 
variable and occurs over a range of conditions rather than at a single 
threshold. Taken together, the LFS SRP results, the acoustic 
propagation modeling, and the Navy's risk assessment model provide an 
estimate of takes of marine mammals.
    The Navy modeled acoustic propagation using its standard acoustical 
performance prediction transmission loss model-PE version 3.4. The 
results of this model are the primary input to the AIM, which the Navy 
used to estimate marine mammal sound exposures. AIM integrates 
simulated movements (including dive patterns) of marine mammals, a 
schedule of SURTASS LFA sonar transmissions, and the predicted sound 
field for each transmission to estimate acoustic exposure during a 
hypothetical SURTASS LFA sonar operation. Description of the PE and AIM 
models, including AIM input parameters for animal movement, diving 
behavior, and marine mammal distribution, abundance, and density, are 
described in detail in the Navy's application and in the DSEIS/SOEIS 
(see Subchapter 4.4 and Appendix C) and are not discussed further in 
this document.
    For this application for rulemaking, the Navy has used the same 
analytical methodology utilized in the first and second five-year rules 
and LOAs to provide reasonable and realistic estimates of the potential 
effects to marine mammals specific to the

[[Page 860]]

potential mission areas as presented in the application. Although this 
proposed rule uses the same analytical methodology the Navy used for 
the 2002-2007 rule, the Navy continuously updates the analysis with new 
marine mammal biological data (behavior, distribution, abundance and 
density) whenever new information becomes available.
    The Navy initially developed 31 acoustic modeling scenarios for the 
major ocean regions in the SURTASS LFA sonar FOEIS/EIS (DoN, 2001); 11 
acoustic modeling scenarios for the 2007 FSEIS and the 2007 rulemaking 
and LOAs; and eight additional sites for the 2011 DSEIS/SOEIS.
    In the initial modeling effort for the 2001 FOEIS/EIS, the Navy 
selected locations to represent the greatest potential effects for each 
of the three major ocean acoustic regimes where SURTASS LFA sonar could 
potentially be used. These acoustic regimes were: (1) Deep-water 
convergence zone propagation, (2) near surface duct propagation, and 
(3) shallow water bottom interaction propagation. The Navy selected 
these sites to model the greatest potential for effects from the use of 
SURTASS LFA sonar incorporating the following factors: (1) closest 
plausible proximity to land (from a SURTASS LFA sonar operations 
standpoint), and/or OBIAs for marine mammals most likely to be 
affected; (2) acoustic propagation conditions that allow minimum 
propagation loss, or transmission loss (TL) (i.e., longest acoustic 
transmission ranges); and (3) time of year selected for maximum animal 
abundance. These 31 sites presented in the Navy's 2001 FOEIS/EIS 
represented the upper bound of impacts (in terms of both possible 
acoustic propagation conditions and marine mammal population and 
density) that could be expected from operation of the SURTASS LFA sonar 
system.
    In the 2007 FSEIS, the Navy provided a risk assessment case study 
that included nine additional sites based on reasonable and realistic 
choices for potential SURTASS LFA sonar testing, training, and 
operations during the proposed period of the rulemaking and LOA 
application. Subsequent to the publication of the 2007 FSEIS, the Navy 
added two additional sites in the waters north and south of the 
Hawaiian Islands. The most recent risk assessment analyses provided in 
the Navy's application and 2011 DSEIS/SOEIS proves updated modeling for 
the 11 sites under the 2007 rulemaking and eight additional sites using 
the most up-to-date marine mammal abundance, density, and behavioral 
information available. These 19 operating sites are in areas of 
potential strategic importance and/or areas of possible naval fleet 
exercises.
    Overall, the Navy's total effort for underwater acoustic modeling 
includes all 50 potential operational sites for SURTASS LFA sonar. The 
analysis of the 50 potential sites provides the foundation for the 
analysis of potential effects of SURTASS LFA sonar operations on the 
overall marine environment.
    If the Navy conducts SURTASS LFA sonar operations in an area that 
was not acoustically modeled in the 2001 FOEIS/EIS (DoN, 2001), the 
2007 FSEIS (DoN, 2007) or the 2011 DSEIS/SOEIS (DoN, 2011), the Navy 
states that the potential effects would most likely be less than those 
analyzed for the most similar site in the analyses because the modeled 
sites represent the upper bound of effects. NMFS concurs with this 
approach, as any site not modeled in the Navy's analyses should fall 
within or under the modeled bounds of impacts of possible acoustic 
propagation conditions and marine mammal densities. The assumptions of 
the 2001 FOEIS/EIS (DoN, 2001) and the 2007 FSEIS (DoN, 2007) are still 
valid and there are no new data to contradict the conclusions made in 
the Navy's documents.
    Risk Analysis. To determine the potential impacts that exposure to 
LF sound from SURTASS LFA sonar operations could have on marine 
mammals, the Navy defined biological risk standards with associated 
measurement parameters. The Navy's measurement parameters for 
determining exposure were RLs in dB, the pulse repetition interval 
(time between pings), and the number of pings received. To address the 
potential for accumulation of effects on marine mammals over a seven to 
20-day period (i.e., the estimated maximum SURTASS LFA sonar mission 
period, allowing for varying RLs and a duty cycle of 20 percent or 
less), the Navy developed a function that translates the modeled 
history of repeated exposures (as calculated in the AIM) into an 
equivalent RL for a single exposure with a comparable risk (as 
previously discussed in the SPL and the Single Ping Equivalent (SPE) 
section). Based upon the best available information, NMFS believes that 
the Navy's assumptions are still valid and there are no new data to 
contradict the conclusions made by the Navy's risk analysis. NMFS 
refers the reader to Section 6.4.3 of the Navy's application and 
Appendix C of the 2011 DSEIS/SOEIS for more detailed information on the 
Navy's risk assessment approach.

Potential Effects of the Specified Activity on Marine Mammals

    The Navy has requested authorization for the incidental take of 
marine mammals that may result from upcoming training, testing, and 
military operations using SURTASS LFA sonar on a maximum of four U.S. 
Naval ships in certain areas of the Pacific, Atlantic, and Indian 
Oceans and the Mediterranean Sea. In addition to the use of LFA and HF/
M3 sonar, the Navy has analyzed the potential impact of ship strike to 
marine mammals from SURTASS LFA sonar operations, and, in consultation 
with NMFS as a cooperating agency for the SURTASS LFA sonar 2011 DSEIS/
SOEIS, has determined that take of marine mammals incidental to this 
non-acoustic component of the Navy's operations is unlikely and, 
therefore, has not requested authorization for take of marine mammals 
that might occur incidental to vessel ship strike. In this document, 
NMFS analyzes the potential effects on marine mammals from exposure to 
LFA and HF/M3 sonar, but also includes some additional analysis of the 
potential impacts from vessel operations.
    For the purpose of MMPA authorizations, NMFS' effects assessments 
serve four primary purposes: (1) Identification of the permissible 
methods of taking, meaning: The nature of the take (e.g., resulting 
from anthropogenic noise versus from ship strike, etc.); the regulatory 
level of take (i.e., mortality versus Level A or Level B harassment) 
and the estimated amount of take; (2) Informing the prescription of 
means of effecting the least practicable adverse impact on such species 
or stock and its habitat (i.e., mitigation); (3) Supporting the 
determination of whether the specified activity will have a negligible 
impact on the affected species or stocks of marine mammals (based on 
the likelihood that the activity will adversely affect the species or 
stock through effects on annual rates of recruitment or survival); and 
(4) Determining whether the specified activity will have an unmitigable 
adverse impact on the availability of the species or stock(s) for 
subsistence uses.
    NMFS' analysis of potential impacts from SURTASS LFA operations 
including lethal responses, physical trauma, sensory impairment 
(permanent and temporary threshold shifts and acoustic masking), 
physiological responses (particularly stress responses), and behavioral 
disturbance

[[Page 861]]

is outlined below this section. NMFS will focus qualitatively on the 
different ways that SURTASS LFA sonar operations may affect marine 
mammals (some of which may not classify as take). Then, in the 
Estimated Take of Marine Mammals Section, NMFS will relate the 
potential effects to marine mammals from SURTASS LFA sonar operations 
to the MMPA definitions of take, including Level A and Level B 
Harassment, and attempt to quantify those effects.
    The potential effects to marine mammals described in the following 
sections do not take into consideration the proposed monitoring and 
mitigation measures described later in this document (see the Proposed 
Mitigation section which, as noted, are designed to effect the least 
practicable adverse impact on affected marine mammals species and 
stocks.

Potential Effects of Exposure to SURTASS LFA Sonar Operations

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

Direct Physiological Effects

Threshold Shift (Noise-Induced Loss of Hearing)

    When animals exhibit reduced hearing sensitivity within their 
auditory range (i.e., sounds must be louder for an animal to detect 
them) following exposure to a sufficiently intense sound or a less 
intense sound for a sufficient duration, it is referred to as a noise-
induced threshold shift (TS). An animal can experience a temporary 
threshold shift (TTS) and/or permanent threshold shift (PTS). TTS can 
last from minutes or hours to days (i.e., there is recovery back to 
baseline/pre-exposure levels), can occur within a specific frequency 
range (i.e., an animal might only have a temporary loss of hearing 
sensitivity within a limited frequency band of its auditory range), and 
can be of varying amounts (for example, an animal's hearing sensitivity 
might be reduced by only six dB or reduced by 30 dB). PTS is permanent 
(i.e., there is incomplete recovery back to baseline/pre-exposure 
levels), but also can occur in a specific frequency range and amount as 
mentioned above for TTS.
    The following physiological mechanisms are thought to play a role 
in inducing auditory TSs: 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 (at least in terrestrial mammals), displacement of certain 
inner ear membranes, increased blood flow, and post-stimulatory 
reduction in both efferent and sensory neural output (Southall et al., 
2007). As amplitude and duration of sound exposure increase, so, 
generally, does the amount of TS, along with the recovery time. Human 
non-impulsive noise exposure guidelines are based on the assumption 
that exposures of equal energy (the same Sound Exposure Level (SEL)) 
producing equal amounts of hearing impairment regardless of how the 
sound energy is distributed in time (NIOSH, 1998). Until recently, 
previous marine mammal TTS studies have also generally supported this 
equal energy relationship (Southall et al., 2007). The amplitude, 
duration, frequency, temporal pattern, and energy distribution of sound 
exposure all affect the amount of associated TS and the frequency range 
in which it occurs. Three studies, two by Mooney et al. (2009a, 2009b) 
on a single bottlenose dolphin either exposed to playbacks of Navy MF 
active sonar or octave-band noise (4-8 kHz) and one by Kastak et al. 
(2007) on a single California sea lion exposed to airborne octave-band 
noise (centered at 2.5 kHz), concluded that for all noise exposure 
situations the equal energy relationship may not be the best indicator 
to predict TTS onset levels. All three of these studies highlight the 
inherent complexity of predicting TTS onset in marine mammals, as well 
as the importance of considering exposure duration when assessing 
potential impacts. Generally, with sound exposures of equal energy, 
those that were quieter (lower sound pressure level (SPL)) with longer 
duration were found to induce TTS onset at lower levels than those of 
louder (higher SPL) and shorter duration. For intermittent sounds, less 
TS will occur than from a continuous exposure with the same energy 
(some recovery can occur between intermittent exposures) (Kryter et 
al., 1966; Ward, 1997; Mooney et al.

[[Page 862]]

2009a, 2009b; Finneran et al. 2010). For example, one short but loud 
(higher SPL) sound exposure may induce the same impairment as one 
longer but softer (lower SPL) sound, which in turn may cause more 
impairment than a series of several intermittent softer sounds with the 
same total energy (Ward, 1997). Additionally, though TTS is temporary, 
very prolonged or repeated exposure to sound strong enough to elicit 
TTS, or shorter-term exposure to sound levels well above the TTS 
threshold can cause PTS, at least in terrestrial mammals (Kryter, 1985; 
Lonsbury-Martin et al. 1987) (although in the case of SURTASS LFA, 
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, 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 cetaceans, published data on the onset of TTS are 
limited to the captive bottlenose dolphin, beluga, harbor porpoise, and 
Yangtze finless porpoise (Finneran et al., 2000, 2002b, 2005a, 2007, 
2010a, 2010b; Schlundt et al., 2000; Nachtigall et al., 2003, 2004; 
Mooney et al., 2009a, 2009b; Lucke et al., 2009; Finneran and Schlundt, 
2010; Popov et al., 2011). For pinnipeds in water, data are limited to 
Kastak et al.'s (1999, 2005) measurement of TTS in one captive harbor 
seal, one captive elephant seal, and one captive California sea lion 
(Finneran et al., 2003 tried to induce TTS in two California sea lions 
but could not).
    Marine mammal hearing plays a critical role in communication with 
conspecifics and in interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. Depending on the degree 
(elevation of threshold in dB), duration (i.e., recovery time), and 
frequency range of TTS, and the context in which it is experienced, TTS 
can have effects on marine mammals ranging from discountable to serious 
(similar to those discussed in auditory masking, below). For example, a 
marine mammal may be able to readily compensate for a brief, relatively 
small amount of TTS in a non-critical frequency range that takes place 
during a time when the animal is traveling through the open ocean, 
where ambient noise is lower and there are not as many competing sounds 
present. Alternatively, a larger amount and longer duration of TTS 
sustained during a time when communication is critical for successful 
mother/calf interactions could have more serious impacts if it were in 
the same frequency band as the necessary vocalizations and of a 
severity that impeded communication. The fact that animals exposed to 
levels and durations of sound that would be expected to result in this 
physiological response would also be expected to have behavioral 
responses of a comparatively more severe or sustained nature is 
potentially more significant than simple existence of a TTS.
    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 than TTS because it is a permanent condition. Of 
note, reduced hearing sensitivity as a simple function of aging has 
been observed in marine mammals, as well as humans and other taxa 
(Southall et al., 2007), so we can infer that strategies exist for 
coping with this condition to some degree, though likely not without 
cost. There is no empirical evidence that exposure to SURTASS LFA sonar 
can cause PTS in any marine mammals; instead the possibility of PTS has 
been inferred from studies of TTS on captive marine mammals (see 
Richardson et al., 1995).

Acoustically Mediated Bubble Growth

    One theoretical cause of injury to marine mammals is rectified 
diffusion (Crum and Mao, 1996), the process of increasing the size of a 
bubble by exposing it to a sound field. This process could be 
facilitated if the environment in which the ensonified bubbles exist is 
supersaturated with gas. Repetitive diving by marine mammals can cause 
the blood and some tissues to accumulate gas to a greater degree than 
is supported by the surrounding environmental pressure (Ridgway and 
Howard, 1979). The deeper and longer dives of some marine mammals 
(e.g., beaked whales) are theoretically predicted to induce greater 
supersaturation (Houser et al., 2001b), although recent preliminary 
empirical data suggests that there is no increase in blood nitrogen 
levels or formation of bubbles in diving bottlenose dolphins (Houser, 
2009). If rectified diffusion were possible in marine mammals exposed 
to high-level sound, conditions of tissue supersaturation could 
theoretically speed the rate and increase the size of bubble growth. 
Subsequent effects due to tissue trauma and emboli would presumably 
mirror those observed in humans suffering from decompression sickness.
    It is unlikely that the short duration of the SURTASS LFA sonar 
pings would be long enough to drive bubble growth to any substantial 
size, if such a phenomenon occurs. However, an alternative but related 
hypothesis has also been suggested; stable bubbles could be 
destabilized by high-level sound exposures such that bubble growth then 
occurs through static diffusion of gas out of the tissues. In such a 
scenario the marine mammal would need to be in a gas-supersaturated 
state for a long enough period of time for bubbles to become of a 
problematic size.
    Yet another hypothesis (decompression sickness) speculates that 
rapid ascent to the surface following exposure to a startling sound 
might produce tissue gas saturation sufficient for the evolution of 
nitrogen bubbles (Jepson et al., 2003; Fernandez et al., 2005). In this 
scenario, the rate of ascent would need to be sufficiently rapid to 
compromise behavioral or physiological protections against nitrogen 
bubble formation. Alternatively, Tyack et al. (2006) studied the deep 
diving behavior of beaked whales and concluded that: ``Using current 
models of breath-hold diving, we infer that their natural diving 
behavior is inconsistent with known problems of acute nitrogen 
supersaturation and embolism.'' Collectively, these hypotheses 
(rectified diffusion and decompression sickness) can be referred to as 
``hypotheses of acoustically-mediated bubble growth.''
    Although theoretical predictions suggest the possibility for 
acoustically mediated bubble growth, there is considerable disagreement 
among scientists as to its likelihood (Piantadosi and Thalmann, 2004; 
Evans and Miller, 2003; Cox et al., 2006; Rommel et al., 2006). Crum 
and Mao (1996) hypothesized that received levels would have to exceed 
190 dB in order for there to be the possibility of significant bubble 
growth due to supersaturation of gases in the blood (i.e., rectified 
diffusion). More recent work conducted by Crum et al. (2005) 
demonstrated the possibility of rectified diffusion for short duration 
signals, but at exposure levels and tissue saturation levels that are 
highly improbable to occur in diving marine mammals. To date, energy 
levels predicted to cause in vivo bubble

[[Page 863]]

formations 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 (Rommel et al., 2006). However, Jepson et 
al. (2003, 2005) and Fernandez et al. (2004, 2005) concluded that in 
vivo bubble formation, which may be exacerbated by deep, long-duration, 
repetitive dives, may explain why beaked whales appear to be 
particularly vulnerable to MF/HF active sonar exposures.
    In 2009, Hooker et al. (2009) tested two mathematical models to 
predict blood and tissue tension N2 (PN2) using field data 
from three beaked whale species: Northern bottlenose whales, Cuvier's 
beaked whales, and Blainville's beaked whales. The researchers aimed to 
determine if physiology (body mass, diving lung volume, and dive 
response) or dive behavior (dive depth and duration, changes in ascent 
rate, and diel behavior) would lead to differences in PN2 
levels and thereby decompression sickness risk between species.
    In their study, they compared results for previously published time 
depth recorder data (Hooker and Baird, 1999; Baird et al., 2006, 2008) 
from Cuvier's beaked whale, Blainville's beaked whale, and northern 
bottlenose whale. They reported that diving lung volume and extent of 
the dive response had a large effect on end-dive PN2. Also, 
results showed that dive profiles had a larger influence on end-dive 
PN2 than body mass differences between species. Despite diel 
changes (i.e., variation that occurs regularly every day or most days) 
in dive behavior, PN2 levels showed no consistent trend. 
Model output suggested that all three species live with tissue 
PN2 levels that would cause a significant proportion of 
decompression sickness cases in terrestrial mammals. The authors 
concluded that the dive behavior of Cuvier's beaked whale was different 
from both Blainville's beaked whale, and northern bottlenose whale, and 
resulted in higher predicted tissue and blood N2 levels (Hooker et al., 
2009) and suggested that the prevalence of Cuvier's beaked whales 
stranding after naval sonar exercises could be explained by either a 
higher abundance of this species in the affected areas or by possible 
species differences in behavior and/or physiology related to MF active 
sonar (Hooker et al., 2009).
    The hypotheses for gas bubble formation related to beaked whale 
strandings is that beaked whales potentially have strong avoidance 
responses to MF active sonars because they sound similar to their main 
predator, the killer whale (Cox et al., 2006; Southall et al., 2007; 
Zimmer and Tyack, 2007; Baird et al.,2008; Hooker et al., 2009). 
Because SURTASS LFA sonar transmissions are lower in frequency (less 
than 500 Hz) and dissimilar in characteristics from those of marine 
mammal predators, or MF active sonars the SURTASS LFA sonar 
transmissions are not expected to cause gas bubble formation or beaked 
whale strandings. Further investigation is needed to further assess the 
potential validity of these hypotheses.

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 as, 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, the detection of frequencies above those of the 
masking stimulus decreases. This principle is expected to apply to 
marine mammals as well because of common biomechanical cochlear 
properties across taxa.
    Richardson et al. (1995b) argued that the maximum radius of 
influence of an industrial noise (including broadband low-frequency 
sound transmission) on a marine mammal is the distance from the source 
to the point at which the noise can barely be heard. This range is 
determined by either the hearing sensitivity of the animal or the 
background noise level present. Industrial masking is most likely to 
affect some species' ability to detect communication calls and natural 
sounds (i.e., surf noise, prey noise, etc.) (Richardson et al., 1995).
    The echolocation calls of toothed whales are subject to masking by 
high-frequency sound. Human data indicate that low-frequency sounds can 
mask high-frequency sounds (i.e., upward masking). Studies on captive 
odontocetes by Au et al. (1974, 1985, 1993) indicate that some species 
may use various processes to reduce masking effects (e.g., adjustments 
in echolocation call intensity or frequency as a function of background 
noise conditions). There is also evidence that the directional hearing 
abilities of odontocetes are useful in reducing masking at the higher 
frequencies these cetaceans use to echolocate, but not at the low-to-
moderate frequencies they use to communicate (Zaitseva et al., 1980). A 
study by Nachtigall and Supin (2008) showed that false killer whales 
adjust their hearing to compensate for ambient sounds and the intensity 
of returning echolocation signals. Holt et al. (2009) measured killer 
whale call source levels and background noise levels in the one to 40 
kHz band and reported that the whales increased their call source 
levels by one dB SPL for every one dB SPL increase in background noise 
level. Similarly, another study on St. Lawrence River belugas reported 
a similar rate of increase in vocalization activity in response to 
passing vessels (Scheifele et al., 2005).
    Parks et al. (2007) provided evidence of behavioral changes in the 
acoustic behaviors of the endangered North Atlantic right whale, and 
the South Atlantic right whale, and suggested that these were 
correlated to increased underwater noise levels. The study indicated 
that right whales might shift the frequency band of their calls to 
compensate for increased in-band background noise. The significance of 
their result is the indication of potential species-wide behavioral 
change in response to gradual, chronic increases in underwater ambient 
noise. Di Iorio and Clark (2010) showed that blue whale calling rates 
vary in association with seismic sparker survey activity, with whales 
calling more on days with survey than on days without surveys. They 
suggested that the whales called more during seismic survey periods as 
a way to compensate for the elevated noise conditions.
    As mentioned previously, the functional hearing ranges of 
mysticetes overlap with the frequencies of the SURTASS LFA sonar 
sources used in the Navy's training and testing, as well as during 
military operations. The closer the characteristics of the masking 
signal to the signal of interest, the more likely masking is to occur. 
The masking effects of the SURTASS LFA sonar signal are

[[Page 864]]

expected to be limited for a number of reasons. First, the frequency 
range (bandwidth) of the system is limited to approximately 30 Hz, and 
the instantaneous bandwidth at any given time of the signal is small, 
on the order of 10 Hz. Second, the average duty cycle is always less 
than 20 percent and, based on past LFA sonar operational parameters 
(2003 to 2012), is nominally 7.5 to 10 percent. Third, given the 
average maximum pulse length (60 sec), and the fact that the signals 
vary and do not remain at a single frequency for more than 10 sec, 
SURTASS LFA sonar is not likely to cause significant masking. The Navy 
provided an analysis of marine mammal hearing and masking in Subchapter 
4.6.1.2 of the 2007 FSEIS and 4.2.5 in the 2011 DSEIS/SOEIS. In other 
words, the LFA sonar transmissions are coherent, narrow bandwidth 
signals of six to 100 sec in length followed by a quiet period of six 
to 15 minutes. Therefore, the effect of masking will be limited because 
animals that use this frequency range typically use broader bandwidth 
signals. As a result, the chances of an LFA sonar sound actually 
overlapping whale calls at levels that would interfere with their 
detection and recognition would be extremely low.

Impaired Communication

    In addition to making it more difficult for animals to perceive 
acoustic cues in their environment, anthropogenic sound presents 
separate challenges for animals that are vocalizing. When they 
vocalize, animals are aware of environmental conditions that affect the 
``active space'' of their vocalizations, which is the maximum area 
within which their vocalizations can be detected before they drop to 
the level of ambient noise (Brenowitz, 2004; Brumm et al., 2004; Lohr 
et al., 2003). Animals are also aware of environmental conditions that 
affect whether listeners can discriminate and recognize their 
vocalizations 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 which reduce 
the signal-to-noise ratio of animal vocalizations, increase the masked 
auditory thresholds of animals listening for such vocalizations, or 
reduce the active space of an animal's vocalizations impair 
communications between animals. Most animals that vocalize have evolved 
strategies to compensate for the effects of short-term or temporary 
increases in background or ambient noise on their songs or calls. 
Although the fitness consequences of these vocal adjustments 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 most 
economical (in terms of biotic costs) response is behavioral avoidance 
of the potential stressor or avoidance of continued exposure to a 
stressor. An animal's second line of defense to stressors involves the 
sympathetic part of the autonomic nervous system and the classical 
``fight or flight'' response which includes the cardiovascular system, 
the gastrointestinal system, the exocrine glands, and the adrenal 
medulla to produce changes in heart rate, blood pressure, and 
gastrointestinal activity that humans commonly associate with 
``stress.'' These responses have a relatively short duration and may or 
may not have significant long-term effect on an animal's welfare.
    An animal's third line of defense to stressors involves its 
neuroendocrine or sympathetic nervous systems; the system that has 
received the most study has been the hypothalmus-pituitary-adrenal 
system (also known as the HPA 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 
functions, which impair 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 fitness will suffer. In these cases, 
the animals will have entered a pre-pathological or pathological state 
which is called ``distress'' (sensu Seyle, 1950) or ``allostatic 
loading'' (sensu McEwen and Wingfield, 2003). This pathological state 
will last until the animal replenishes its biotic reserves sufficient 
to restore normal function. Note that these examples involve a long-
term (days or weeks) stress response exposure to stimuli.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses have also been documented

[[Page 865]]

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).
    There is limited information on the physiological responses of 
marine mammals to anthropogenic sound exposure, as most observations 
have been limited to short-term behavioral responses, which included 
cessation of feeding, resting, or social interactions. Despite the 
dearth of information on stress responses for marine mammals exposed to 
anthropogenic sounds, studies of other marine animals and terrestrial 
animals lead us to expect some marine mammals to experience 
physiological stress responses and, perhaps, physiological responses 
that would be classified as ``distress'' upon exposure to low-frequency 
sounds. For example, Jansen (1998) reported on the relationship between 
acoustic exposures and physiological responses that are indicative of 
stress responses in humans (e.g., elevated respiration and increased 
heart rates). Jones (1998) reported on reductions in human performance 
when faced with acute, repetitive exposures to acoustic disturbance. 
Trimper et al. (1998) reported on the physiological stress responses of 
osprey to low-level aircraft noise while Krausman et al. (2004) 
reported on the auditory and physiology stress responses of endangered 
Sonoran pronghorn to military overflights. Smith et al. (2004a, 2004b) 
identified noise-induced physiological transient stress responses in 
hearing-specialist fish (i.e., goldfish) that accompanied short- and 
long-term hearing losses. Welch and Welch (1970) reported physiological 
and behavioral stress responses that accompanied damage to the inner 
ears of fish and several mammals.
    Hearing is one of the primary senses marine mammals use to gather 
information about their environment and communicate with conspecifics. 
Although empirical information on the relationship between sensory 
impairment (TTS, PTS, and acoustic masking) 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), NMFS also assumes that stress responses could 
persist beyond the time interval required for animals to recover from 
TTS and might result in pathological and pre-pathological states that 
would be as significant as behavioral responses 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 (in both 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 
the sound to biologically relevant sounds in the animal's environment 
(i.e., calls of predators, prey, or conspecifics), and familiarity of 
the sound may affect the way an animal responds to the sound (Southall 
et al., 2007). 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.
    Exposure of marine mammals to sound sources can result in, but is 
not limited to, no response or any of the following observable 
responses: increased alertness; orientation or attraction to a sound 
source; vocal modifications; cessation of feeding; cessation of social 
interaction; alteration of movement or diving behavior; avoidance; 
habitat abandonment (temporary or permanent); and, in severe cases, 
panic, flight, stampede, or stranding, potentially resulting in death 
(Southall et al., 2007). A review of marine mammal responses to 
anthropogenic sound was first conducted by Richardson (1995). A more 
recent review (Nowacek et al., 2007) addresses 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 
subsections provide examples of behavioral responses that provide an 
idea of the variability in behavioral responses that would be expected 
given the different sensitivities of marine mammal species to sound and 
the wide range of potential acoustic sources to which a marine mammal 
may be exposed. 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.
    Alteration of Diving or Movement. Changes in dive behavior can vary 
widely. They may consist of increased or decreased dive times and 
surface intervals as well as changes in the rates of ascent and descent 
during a dive. Variations in dive behavior may reflect interruptions in 
biologically significant activities (e.g., foraging) or they may be of 
little biological significance. Variations in dive behavior may also 
expose an animal to potentially harmful conditions (e.g., increasing 
the chance of ship-strike) or may serve as an avoidance response that 
enhances survivorship. The impact of a variation in diving resulting 
from an acoustic 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, a reaction, 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

[[Page 866]]

the sound exposure cannot be decoupled from the physical presence of a 
surface vessel, thus complicating interpretations of the relative 
contribution of each stimulus to the response. Indeed, the presence of 
surface vessels, their approach, and the speed of approach, all seemed 
to be significant factors in the response of the Indo-Pacific humpback 
dolphins (Ng and Leung, 2003). Low-frequency signals of the Acoustic 
Thermometry of Ocean Climate (ATOC) sound source were not found to 
affect dive times of humpback whales in Hawaiian waters (Frankel and 
Clark, 2000) or to overtly affect elephant seal dives (Costa et al., 
2003). They did, however, produce subtle effects that varied in 
direction and degree among the individual seals, illustrating the 
varied nature of behavioral effects and consequent difficulty in 
defining and predicting them.
    Foraging. Disruption of feeding behavior can be difficult to 
correlate with anthropogenic sound exposure, so it is usually inferred 
by observed displacement from known foraging areas, the appearance of 
secondary indicators (e.g., bubble nets or sediment plumes), or changes 
in dive behavior. Noise from seismic surveys was not found to impact 
the feeding behavior of western gray whales off the coast of Russia 
(Yazvenko et al., 2007) and sperm whales engaged in foraging dives did 
not abandon dives when exposed to distant signatures of seismic airguns 
(Madsen et al., 2006). Balaenopterid whales exposed to moderate SURTASS 
LFA sonar demonstrated no responses or change in foraging behavior that 
could be attributed to the low-frequency sounds (Croll et al., 2001), 
whereas five out of six North Atlantic right whales exposed to an 
acoustic alarm interrupted their foraging dives (Nowacek et al., 2004). 
Although the received sound pressure level was similar in the latter 
two studies, the frequency, duration, and temporal pattern of signal 
presentation were different. These factors, as well as differences in 
species sensitivity, are likely contributing factors to the 
differential response. 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.
    Brownell (2004) reported the behavioral responses of western gray 
whales off the northeast coast of Sakhalin Island to sounds produced by 
local seismic activities. In 1997, the gray whales responded to seismic 
activities by changing their swimming speed and orientation, 
respiration rates, and distribution in waters around the seismic 
surveys. In 2001, seismic activities were conducted in a known foraging 
ground and the whales left the area and moved farther south to the Sea 
of Okhotsk. They only returned to the foraging ground several days 
after the seismic activities stopped. The potential fitness 
consequences of displacing these whales, especially mother-calf pairs 
and ``skinny whales,'' outside of their normal feeding area are not 
known; however, because gray whales, like other large whales, must gain 
enough energy during the summer foraging season to last them the entire 
year, sounds or other stimuli that cause them to abandon a foraging 
area for several days could disrupt their energetics (i.e., the 
measurement of energy flow through an animal, from what goes into an 
animal as food (prey) to how the animal converts that energy for 
growth, reproduction, maintenance, and metabolism) and force them to 
make trade-offs like delaying their migration south, delaying 
reproduction, reducing growth, or migrating with reduced energy 
reserves.
    Social Relationships. Social interactions between mammals can be 
affected by noise via the disruption of communication signals or by the 
displacement of individuals. Sperm whales responded to military sonar, 
apparently from a submarine, by dispersing from social aggregations, 
moving away from the sound source, remaining relatively silent, and 
becoming difficult to approach (Watkins et al., 1985). In contrast, 
sperm whales in the Mediterranean that were exposed to submarine sonar 
continued calling (J. Gordon pers. comm. cited in Richardson et al., 
1995). Social disruptions must be considered, however, in context of 
the relationships that are affected. While some disruptions may not 
have deleterious effects, long-term or repeated disruptions of mother/
calf pairs or interruption of mating behaviors have the potential to 
affect the growth and survival or reproductive effort/success of 
individuals.
    Vocalizations. (also see Masking Section)--Vocal changes in 
response to anthropogenic noise can occur across the repertoire of 
sound production modes used by marine mammals, such as whistling, 
echolocation click production, calling, and singing. Changes may result 
in response to a need to compete with an increase in background noise 
or may reflect an increased vigilance or startle response. For example, 
in the presence of low-frequency active sonar, humpback whales have 
been observed to increase the length of their ``songs'' (Miller et al., 
2000; Fristrup et al., 2003), possibly due to the overlap in 
frequencies between the whale song and the low-frequency active sonar. 
A similar compensatory effect for the presence of low-frequency vessel 
noise has been suggested for right whales; right whales have been 
observed to shift the frequency content of their calls upward while 
reducing the rate of calling in areas of increased anthropogenic noise 
(Parks et al., 2007). Killer whales off the northwestern coast of the 
United States have been observed to increase the duration of primary 
calls once a threshold in observing vessel density (e.g., whale 
watching) was reached, which has been suggested as a response to 
increased masking noise produced by the vessels (Foote et al., 2004). 
In contrast, both sperm and pilot whales potentially ceased sound 
production during the Heard Island feasibility test (Bowles et al., 
1994), although it cannot be absolutely determined whether the 
inability to acoustically detect the animals was due to the cessation 
of sound production or the displacement of animals from the area.
    Avoidance. Avoidance is the displacement of an individual from an 
area as a result of the presence of a sound. Richardson et al. (1995) 
noted that avoidance reactions are the most obvious manifestations of 
disturbance in marine mammals. Avoidance is qualitatively different 
from the flight response, but also differs in the magnitude of the 
response (i.e., directed movement, rate of travel, etc.). Oftentimes, 
avoidance is temporary and animals return to the area once the noise 
has ceased. However, longer term displacement is possible and can lead 
to changes in abundance or distribution patterns of the species in the 
affected region if animals do not become acclimated to the presence of 
the chronic sound (Blackwell et al., 2004; Bejder et al., 2006; 
Teilmann et al., 2006). Acute avoidance responses have been observed in 
captive porpoises and pinnipeds exposed to a number of different sound 
sources (Kastelein et al., 2001; Finneran et al., 2003; Kastelein et 
al., 2006a; Kastelein et al., 2006b). Short-term avoidance of seismic 
surveys, low-frequency emissions, and acoustic deterrents have also 
been noted in wild populations of odontocetes (Bowles et al., 1994; 
Goold, 1996; 1998; Stone et al., 2000; Morton and Symonds, 2002) and to 
some extent in mysticetes (Gailey et al., 2007), while

[[Page 867]]

long-term or repetitive/chronic displacement for some dolphin groups 
and for manatees has been suggested to result from the presence of 
chronic vessel noise (Haviland-Howell et al., 2007; Miksis-Olds et al., 
2007).
    In 1998, the Navy conducted a Low Frequency Sonar Scientific 
Research Program (LFS SRP) to investigate avoidance behavior of gray 
whales to low frequency sound signals. The objective was to determine 
whether whales respond more strongly to received levels (RL), sound 
gradient, or distance from the source, and to compare whale avoidance 
responses to an LF source in the center of the migration corridor 
versus in the offshore portion of the migration corridor. A single 
source was used to broadcast LFA sonar sounds up to 200 dB. The Navy 
reported that the whales showed some avoidance responses when the 
source was moored one mile (1.8 km) offshore, in the migration path, 
but returned to their migration path when they were a few kilometers 
from the source. When the source was moored two miles (3.7 km) 
offshore, responses were much less, even when the source level was 
increased to 200 dB re: 1 [micro]Pa, to achieve the same RL for most 
whales in the middle of the migration corridor. Also, the researchers 
noted that the offshore whales did not seem to avoid the louder 
offshore source.
    Also during the LFS SRP, researchers sighted numerous odontocete 
and pinniped species in the vicinity of the sound exposure tests with 
LFA sonar. The MF and HF hearing specialists present in the study area 
showed no immediately obvious responses or changes in sighting rates as 
a function of source conditions. Consequently, the researchers 
concluded that none of these species had any obvious behavioral 
reaction to LFA signals at received levels similar to those that 
produced only minor but short-term behavioral responses in the baleen 
whales (i.e., LF hearing specialists) (Clark and Southall, 2009). Thus, 
for odontocetes, the chances of injury and/or significant behavioral 
responses to SURTASS LFA sonar would be low given the MF/HF 
specialists' observed lack of response to LFA sounds during the LFS SRP 
and due to the MF/HF frequencies to which these animals are adapted to 
hear (Clark and Southall, 2009).
    Maybaum (1993) conducted sound playback experiments to assess the 
effects of mid-frequency active sonar on humpback whales in Hawaiian 
waters. Specifically, she exposed focal pods to sounds of a 3.3-kHz 
sonar pulse, a sonar frequency sweep from 3.1 to 3.6 kHz, and a control 
(blank) tape while monitoring the behavior, movement, and underwater 
vocalizations. The two types of sonar signals differed in their effects 
on the humpback whales, but both resulted in avoidance behavior. The 
whales responded to the pulse by increasing their distance from the 
sound source and responded to the frequency sweep by increasing their 
swimming speeds and track linearity. In the Caribbean, sperm whales 
avoided exposure to mid-frequency submarine sonar pulses, in the range 
of 1000 Hz to 10,000 Hz (IWC 2005).
    Kvadsheim et al., (2007) conducted a controlled exposure experiment 
in which killer whales fitted with D-tags were exposed to mid-frequency 
active sonar (Source A: A 1.0 s upsweep 209 dB @ 1-2 kHz every 10 sec 
for 10 minutes; Source B: With a 1.0 s upsweep 197 dB @ 6-7 kHz every 
10 sec for 10 min). When exposed to Source A, a tagged whale and the 
group it was traveling with did not appear to avoid the source. When 
exposed to Source B, the tagged whales along with other whales that had 
been carousel feeding (where killer whales cooperatively herd fish 
schools into a tight ball towards the surface and feed on the fish 
which have been stunned by tailslaps and subsurface feeding (Simila, 
1997) ceased feeding during the approach of the sonar and moved rapidly 
away from the source. When exposed to Source B, Kvadsheim and his co-
workers reported that a tagged killer whale seemed to try to avoid 
further exposure to the sound field by the following behaviors: 
Immediately swimming away (horizontally) from the source of the sound; 
engaging in a series of erratic and frequently deep dives that seemed 
to take it below the sound field; or swimming away while engaged in a 
series of erratic and frequently deep dives. Although the sample sizes 
in this study are too small to support statistical analysis, the 
behavioral responses of the orcas were consistent with the results of 
other studies.
    In 2007, the first in a series of behavioral response studies (BRS) 
on deep diving odontocetes conducted by NMFS and other scientists 
showed one beaked whale (Mesoplodon densirostris) responding to an MF 
active sonar playback. The BRS-07 cruise report 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 BRS-07 cruise report notes that the results are from a single 
experiment and that a greater sample size is needed before robust and 
definitive conclusions can be drawn (NMFS, 2008a).
    In the 2008 BRS study, researchers identified an emerging pattern 
of responses of deep-diving beaked whales to MF active sonar playbacks. 
For example, Blainville's beaked whales--a resident species within the 
Tongue of the Ocean, Bahamas study area--appear to be sensitive to 
noise at levels well below expected TTS (approximately 160 dB re: 
1[mu]Pa at 1 m). 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 MF active 
sonar, which suggests that beaked whales may not respond to the 
specific sound signatures. Instead, they may be sensitive to any pulsed 
sound from a point source in the frequency range of the MF active sonar 
transmission. The response to such stimuli appears to involve the 
beaked whale increasing the distance between it and the sound source 
(NMFS, 2008b).
    In the 2010 BRS study, researchers again used controlled exposure 
experiments (CEE) to carefully measure behavioral responses of 
individual animals to sound exposures of MF active sonar and pseudo-
random noise. For each sound type, some exposures were conducted when 
animals were in a surface feeding (approximately 164 ft (50 m) or less) 
and/or socializing behavioral state and others while animals were in a 
deep feeding (greater than 164 ft (50 m)) and/or traveling mode. The 
researchers conducted the largest number of CEEs on blue whales (n=19) 
and of these, 11 CEEs involved exposure to the MF active sonar sound 
type.
    For the majority of CEE transmissions of either sound type, they 
noted few obvious behavioral responses detected either by the visual 
observers or on initial inspection of the tag data. The researchers 
observed that throughout the CEE transmissions, up to the highest 
received sound level (absolute RMS value approximately 160 dB re: 
1[mu]Pa with signal-to-noise ratio values over 60 dB), two blue whales 
continued surface feeding behavior and remained at a range of around 
3,820 ft (1,000 m) from the sound source (Southall et al., 2011).

[[Page 868]]

In contrast, another blue whale (later in the day and greater than 11.5 
mi (18.5 km; 10 nmi) from the first CEE location) exposed to the same 
stimulus (MFA) while engaged in a deep feeding/travel state exhibited a 
different response. In that case, the blue whale responded almost 
immediately following the start of sound transmissions when received 
sounds were just above ambient background levels (Southall et al., 
2011). However, the authors note that this kind of temporary avoidance 
behavior was not evident in any of the nine CEEs involving blue whales 
engaged in surface feeding or social behaviors, but was observed in 
three of the ten CEEs for blue whales in deep feeding/travel behavioral 
modes (one involving MFA sonar; two involving pseudo-random noise) 
(Southall et al., 2011). The results of this study further illustrate 
the importance of behavioral context in understanding and predicting 
behavioral responses.
    Flight Response. A flight response is a dramatic change in normal 
movement to a directed and rapid movement away from the perceived 
location of a sound source. Relatively little information on flight 
responses of marine mammals to anthropogenic signals exist, although 
observations of flight responses to the presences of predators have 
occurred (Connor and Heithaus, 1996). Flight responses have been 
speculated as being a component of marine mammal strandings associated 
with MF active sonar activities (Evans and England, 2001). If marine 
mammals respond to Navy vessels that are transmitting active sonar in 
the same way that they might respond to a predator, their probability 
of flight responses should increase when they perceive that Navy 
vessels are approaching them directly, because a direct approach may 
convey detection and intent to capture (Burger and Gochfeld, 1981, 
1990; Cooper, 1997, 1998). In addition to the limited data on flight 
response for marine mammals, there are examples for terrestrial 
species. For instance, the probability of flight responses in Dall's 
sheep Ovis dalli dalli (Frid, 2001a, 2001b), ringed seals Phoca hispida 
(Born et al., 1999), Pacific brant (Branta bernicl nigricans), and 
Canada geese (B. Canadensis) increased as a helicopter or fixed-wing 
aircraft more directly approached groups of these animals (Ward et al., 
1999). Bald eagles (Haliaeetus leucocephalus) perched on trees 
alongside a river were also more likely to flee from a paddle raft when 
their perches were closer to the river or were closer to the ground 
(Steidl and Anthony, 1996).
    Breathing. Variations in respiration naturally occur with different 
behaviors. Variations in respiration rate as a function of acoustic 
exposure can co-occur with other behavioral reactions, such as a flight 
response or an alteration in diving. However, respiration rates in and 
of themselves may be representative of annoyance or an acute stress 
response. Mean exhalation rates of gray whales at rest and while diving 
were found to be unaffected by seismic surveys conducted adjacent to 
foraging grounds (Gailey et al., 2007). Studies with captive harbor 
porpoises showed increased respiration rates upon introduction of 
acoustic alarms (Kastelein et al., 2001; Kastelein et al., 2006a) and 
emissions for underwater data transmission (Kastelein et al., 2005). 
However, exposing the same acoustic alarm to a striped dolphin under 
the same conditions did not elicit a response (Kastelein et al., 
2006a), again highlighting the importance of understanding species 
differences in the tolerance of underwater noise when determining the 
potential for impacts resulting from anthropogenic sound exposure.
    Continued Pre-disturbance Behavior and Habituation. Under some 
circumstances, some of the individual marine mammals that are exposed 
to active sonar transmissions will continue their normal behavioral 
activities; in other circumstances, individual animals will respond to 
sonar transmissions at lower received levels and move to avoid 
additional exposure or exposures at higher received levels (Richardson 
et al., 1995).
    It is difficult to distinguish between animals that continue their 
pre-disturbance behavior without stress responses, animals that 
continue their behavior but experience stress responses (that is, 
animals that cope with disturbance), and animals that habituate to 
disturbance (that is, they may have experienced low-level stress 
responses initially, but those responses abated over time). Watkins 
(1986) reviewed data on the behavioral reactions of fin, humpback, 
right and minke whales that were exposed to continuous, broadband low-
frequency shipping and industrial noise in Cape Cod Bay. He concluded 
that underwater sound was the primary cause of behavioral reactions in 
these species of whales and that the whales responded behaviorally to 
acoustic stimuli within their respective hearing ranges. Watkins also 
noted that whales showed the strongest behavioral reactions to sounds 
in the 15 Hz to 28 kHz range, although negative reactions (avoidance, 
interruptions in vocalizations, etc.) were generally associated with 
sounds that were either unexpected, too loud, suddenly louder or 
different, or perceived as being associated with a potential threat 
(such as an approaching ship on a collision course). In particular, 
whales seemed to react negatively when they were within 100 m of the 
source or when received levels increased suddenly in excess of 12 dB 
relative to ambient sounds. At other times, the whales ignored the 
source of the signal and all four species habituated to these sounds. 
Nevertheless, Watkins concluded that whales ignored most sounds in the 
background of ambient noise, including sounds from distant human 
activities even though these sounds may have had considerable energies 
at frequencies well within the whales' range of hearing. Further, he 
noted that of the whales observed, fin whales were the most sensitive 
of the four species, followed by humpback whales; right whales were the 
least likely to be disturbed and generally did not react to low-
amplitude engine noise. By the end of his period of study, Watkins 
(1986) concluded that fin and humpback whales have generally habituated 
to the continuous and broad-band noise of Cape Cod Bay while right 
whales did not appear to change their response. As mentioned above, 
animals that habituate to a particular disturbance may have experienced 
low-level stress responses initially, but those responses abated over 
time. In most cases, this likely means a lessened immediate potential 
effect from a disturbance. However, there is cause for concern where 
the habituation occurs in a potentially more harmful situation. For 
example, animals may become more vulnerable to vessel strikes once they 
habituate to vessel traffic (Swingle et al., 1993; Wiley et al., 1995).
    Aicken et al., (2005) monitored the behavioral responses of marine 
mammals to a new low-frequency active sonar system that was being 
developed for use by the British Navy. During those trials, fin whales, 
sperm whales, Sowerby's beaked whales, long-finned pilot whales 
(Globicephala melas), Atlantic white-sided dolphins, and common 
bottlenose dolphins were observed and their vocalizations were 
recorded. These monitoring studies detected no evidence of behavioral 
responses that the investigators could attribute to exposure to the 
low-frequency active sonar during these trials.
    Behavioral Responses. Southall et al. (2007) reviewed the available 
literature on marine mammal hearing and physiological and behavioral 
responses to human-made sound with the goal of

[[Page 869]]

proposing exposure criteria for certain effects. This peer-reviewed 
compilation of literature is very valuable, though Southall et al. 
(2007) note that not all data are equal: Some have poor statistical 
power, insufficient controls, and/or limited information on received 
levels, background noise, and other potentially important contextual 
variables. Such data were reviewed and sometimes used for qualitative 
illustration, but no quantitative criteria were recommended for 
behavioral responses. All of the studies considered, however, contain 
an estimate of the received sound level when the animal exhibited the 
indicated response.
    In the Southall et al. (2007) publication, for the purposes of 
analyzing responses of marine mammals to anthropogenic sound and 
developing criteria, the authors differentiate between single pulse 
sounds, multiple pulse sounds, and non-pulse sounds. LFA sonar is 
considered a non-pulse sound. Southall et al. (2007) summarizes the 
studies associated with low-frequency, mid-frequency, and high-
frequency cetacean and pinniped responses to non-pulse sounds, based 
strictly on received level, in Appendix C of their article 
(incorporated by reference and summarized in the following paragraphs).
    The studies that address responses of low-frequency cetaceans to 
non-pulse sounds include data gathered in the field and related to 
several types of sound sources, including: Vessel noise, drilling and 
machinery playback, low-frequency M-sequences (sine wave with multiple 
phase reversals) playback, tactical low-frequency active sonar 
playback, drill ships, Acoustic Thermometry of Ocean Climate (ATOC) 
source, and non-pulse playbacks. These studies generally indicate no 
(or very limited) responses to received levels in the 90 to 120 dB re: 
1 [mu]Pa at 1 m range and an increasing likelihood of avoidance and 
other behavioral effects in the 120 to 160 dB re: 1 [mu]Pa at 1 m 
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 a received level. Also, few of the 
laboratory or field datasets had common conditions, behavioral 
contexts, or sound sources, so it is not surprising that responses 
differ.
    The studies that address responses of mid-frequency cetaceans to 
non-pulse sounds include data gathered both in the field and the 
laboratory and related to several different sound sources including: 
Pingers, drilling playbacks, ship and ice-breaking noise, vessel noise, 
Acoustic Harassment Devices (AHDs), Acoustic Deterrent Devices (ADDs), 
MF active sonar, and non-pulse bands and tones. Southall et al. (2007) 
were unable to come to a clear conclusion regarding the results of 
these studies. In some cases, animals in the field showed significant 
responses to received levels between 90 and 120 dB re: 1 [mu]Pa at 1 m, 
while in other cases these responses were not seen in the 120 to 150 dB 
re: 1 [mu]Pa at 1 m range. The disparity in results was likely due to 
contextual variation and the differences between the results in the 
field and laboratory data (animals typically responded at lower levels 
in the field).
    The studies that address responses of high-frequency cetaceans to 
non-pulse sounds include data gathered both in the field and the 
laboratory and related to several different sound sources including: 
Pingers, AHDs, and various laboratory non-pulse sounds. All of these 
data were collected from harbor porpoises. Southall et al. (2007) 
concluded that the existing data indicate that harbor porpoises are 
likely sensitive to a wide range of anthropogenic sounds at low 
received levels (approximately 90-120 dB re: 1 [mu]Pa at 1 m), at least 
for initial exposures. All recorded exposures above 140 dB re: 1 [mu]Pa 
at 1 m induced profound and sustained avoidance behavior in wild harbor 
porpoises (Southall et al., 2007). Rapid habituation was noted in some 
but not all studies. There are no data to indicate whether other high-
frequency cetaceans are as sensitive to anthropogenic sound as harbor 
porpoises.
    The studies that address the responses of pinnipeds in water to 
non-pulse sounds include data gathered both in the field and the 
laboratory and related to several different sound sources including: 
AHDs, ATOC, various non-pulse sounds used in underwater data 
communication, underwater drilling, and construction noise. Few studies 
exist with enough information to include them in the analysis. The 
limited data suggest that exposure to non-pulse sounds between 90 and 
140 dB re: 1 [mu]Pa at 1 m generally do not result in strong behavioral 
responses of pinnipeds in water, but no data exist at higher received 
levels.
    In addition to summarizing the available data, Southall et al. 
(2007) developed a behavioral response severity scaling system with the 
intent of ultimately being able to assign some level of biological 
significance to a response. Following is a summary of their scoring 
system (a comprehensive list of the behaviors associated with each 
score is in the report):
     0-3 (Minor and/or brief behaviors) includes, but is not 
limited to: No response; minor changes in speed or locomotion (but with 
no avoidance); individual alert behavior; minor cessation in vocal 
behavior; minor changes in response to trained behaviors (in 
laboratory)
     4-6 (Behaviors with higher potential to affect foraging, 
reproduction, or survival) includes, but is not limited to: Moderate 
changes in speed, direction, or dive profile; brief shift in group 
distribution; prolonged cessation or modification of vocal behavior 
(duration greater than the duration of sound); minor or moderate 
individual and/or group avoidance of sound; brief cessation of 
reproductive behavior; or refusal to initiate trained tasks (in 
laboratory)
     7-9 (Behaviors considered likely to affect vital rates) 
includes, but is not limited to: Extensive or prolonged aggressive 
behavior; moderate, prolonged, or significant separation of females and 
dependent offspring with disruption of acoustic reunion mechanisms; 
long-term avoidance of an area; outright panic, stampede, stranding; 
threatening or attacking sound source (in laboratory).
    In Table 22, NMFS has summarized the scores that Southall et al. 
(2007) assigned to the papers that reported behavioral responses of 
low-frequency cetaceans, mid-frequency cetaceans, and pinnipeds in 
water to non-pulse sounds. This table is included simply to summarize 
the findings of the studies and opportunistic observations (all of 
which were capable of estimating received level) that Southall et al. 
(2007) compiled in an effort to develop acoustic criteria.

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[GRAPHIC] [TIFF OMITTED] TP06JA12.002

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 are few quantitative marine mammal data relating the 
exposure of marine mammals to sound to effects on reproduction or 
survival, though data exist for terrestrial species to which we can 
draw comparisons for marine mammals. Several authors have reported that 
disturbance stimuli cause animals to abandon nesting and foraging sites 
(Sutherland and Crockford, 1993), cause animals to increase their 
activity levels and suffer premature deaths or reduced reproductive 
success when their energy expenditures exceed their energy budgets 
(Daan et al., 1996; Feare, 1976; Giese, 1996; Mullner et al., 2004; 
Waunters et al., 1997), or cause animals to experience higher predation 
rates when they adopt risk-prone foraging or migratory strategies (Frid 
and Dill, 2002). Each of these studies addressed the consequences of 
animals shifting from one behavioral state (e.g., resting or foraging) 
to another behavioral state (e.g., avoidance or escape behavior) 
because of human disturbance or disturbance stimuli.
    One consequence of behavioral avoidance results from the changes in 
energetics of marine mammals because of the energy required to avoid 
surface vessels or the sound field associated with active sonar (Frid 
and Dill, 2002). Most animals can avoid that energetic cost by swimming 
away at slow speeds or speeds that minimize the cost of transport 
(Miksis-Olds, 2006), as has been demonstrated in Florida manatees 
(Hartman, 1979; Miksis-Olds, 2006).
    Those costs increase, however, when animals shift from a resting 
state, which is designed to conserve an animal's energy, to an active 
state that consumes energy the animal would have conserved had it not 
been disturbed. Marine mammals that have been disturbed by 
anthropogenic noise and vessel approaches are commonly reported to 
shift from resting behavioral states to active behavioral states, which 
would imply that they incur an energy cost.
    Morete et al., (2007) reported that undisturbed humpback whale cows 
that were accompanied by their calves were frequently observed resting 
while their calves circled them (milling). When vessels approached, the 
amount of time cows and calves spent resting and milling, respectively, 
declined significantly. These results are similar to those reported by 
Scheidat et al. (2004) for the humpback whales they observed off the 
coast of Ecuador.
    Constantine and Brunton (2001) reported that bottlenose dolphins in 
the Bay of Islands, New Zealand only engaged in resting behavior five 
percent of the time when vessels were within 300 m compared with 83 
percent of the time when vessels were not present. Miksis-Olds (2006) 
and Miksis-Olds et al. (2005) reported that Florida manatees in 
Sarasota Bay, Florida, reduced the amount of time they spent milling 
and increased the amount of time they spent feeding when background 
noise levels increased. Although the acute costs of these changes in 
behavior are not likely to exceed an animal's ability to compensate, 
the chronic costs of these behavioral shifts are uncertain.
    Attention is the cognitive process of selectively concentrating on 
one aspect of an animal's environment while ignoring other things 
(Posner, 1994). Because animals (including humans) have limited 
cognitive resources, there is a limit to how much sensory information 
they can process at any time. The phenomenon called ``attentional 
capture'' occurs when a stimulus (usually a stimulus that an animal is 
not concentrating on or attending to) ``captures'' an animal's 
attention. This shift in attention can occur consciously or 
unconsciously (e.g., when an animal hears sounds that it associates 
with the approach of a predator) and the shift in attention can be 
sudden (Dukas, 2002; van Rij, 2007). Once a stimulus has captured an 
animal's attention, the animal can respond by ignoring the stimulus, 
assuming a ``watch and wait'' posture, or treating the stimulus as a 
disturbance and responding accordingly, which includes scanning for the 
source of the stimulus or ``vigilance'' (Cowlishaw et al., 2004).
    Vigilance is normally an adaptive behavior that helps animals 
determine the presence or absence of predators, assess their distance 
from conspecifics, or attend to cues from prey (Bednekoff

[[Page 871]]

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 (e.g., multiple surface vessels), or when they co-occur with 
times that an animal perceives increased risk (e.g., when they are 
giving birth or accompanied by a calf). Most of the published 
literature, however, suggests that direct approaches will increase the 
amount of time animals will dedicate to being vigilant. An example of 
this concept with terrestrial species involved bighorn sheep and Dall's 
sheep, which dedicated more time to being vigilant, and less time 
resting or foraging, when aircraft made direct approaches over them 
(Frid, 2001; Stockwell et al., 1991).
    Several authors have established that long-term and intense 
disturbance stimuli can cause population declines by reducing the 
physical condition of individuals that have been disturbed, followed by 
reduced reproductive success, reduced survival, or both (Daan et al., 
1996; Madsen, 1994; White, 1983). For example, Madsen (1994) reported 
that pink-footed geese (Anser brachyrhynchus) in undisturbed habitat 
gained body mass and had about a 46 percent reproductive success rate 
compared with geese in disturbed habitat (being consistently scared off 
the fields on which they were foraging) which did not gain mass and had 
a 17 percent reproductive success rate. Similar reductions in 
reproductive success have been reported for other non-marine mammal 
species; for example, mule deer (Odocoileus hemionus) disturbed by all-
terrain vehicles (Yarmoloy et al., 1988), caribou disturbed by seismic 
exploration blasts (Bradshaw et al., 1998), and caribou disturbed by 
low-elevation military jet flights (Luick et al., 1996; Harrington and 
Veitch, 1992). Similarly, a study of elk (Cervus elaphus) that were 
disturbed experimentally by pedestrians concluded that the ratio of 
young to mothers was inversely related to disturbance rate (Phillips 
and Alldredge, 2000).
    The primary mechanism by which increased vigilance and disturbance 
appear to affect the fitness of individual animals is by disrupting an 
animal's time budget, reducing the time they might spend foraging and 
resting (which increases an animal's activity rate and energy demand). 
An example of this concept with terrestrial species involved, a study 
of grizzly bears (Ursus horribilis) which reported that bears disturbed 
by hikers reduced their energy intake by an average of 12 kilocalories/
min (50.2 x 10\3\ kiloJoules/min), and spent energy fleeing or acting 
aggressively toward hikers (White et al., 1999). Alternately, Ridgway 
et al., (2006) reported that increased vigilance in bottlenose dolphins 
exposed to sound over a five-day period did not cause any sleep 
deprivation or stress effects such as changes in cortisol or 
epinephrine levels.
    On a related note, many animals perform vital functions, such as 
feeding, resting, traveling, and socializing, on a diel cycle (24-hr 
cycle). Behavioral reactions to noise exposure (such as disruption of 
critical life functions, displacement, or avoidance of important 
habitat) are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007).

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 under the MMPA is that ``(A) a marine mammal is dead and is 
(i) on a beach or shore of the United States; or (ii) in waters under 
the jurisdiction of the United States (including any navigable waters); 
or (B) a marine mammal is alive and is (i) on a beach or shore of the 
United States and is unable to return to the water; (ii) on a beach or 
shore of the United States and, although able to return to the water, 
is in need of apparent medical attention; or (iii) in the waters under 
the jurisdiction of the United States (including any navigable waters), 
but is unable to return to its natural habitat under its own power or 
without assistance'' (16 U.S.C. 1421h).
    Marine mammals are known to strand for a variety of reasons, such 
as infectious agents, biotoxicosis, starvation, fishery interaction, 
ship strike, unusual oceanographic or weather events, sound exposure, 
or combinations of these stressors sustained concurrently or in series. 
However, the cause or causes of most strandings are unknown (Geraci et 
al., 1976; Eaton, 1979; Odell et al., 1980; Best, 1982). Numerous 
studies suggest that the physiology, behavior, habitat relationships, 
age, or condition of cetaceans may cause them to strand or might pre-
dispose them to strand when exposed to another phenomenon. These 
suggestions are consistent with the conclusions of numerous other 
studies that have demonstrated that combinations of dissimilar 
stressors commonly combine to kill an animal or dramatically reduce its 
fitness, even though one exposure without the other does not produce 
the same result (Chroussos, 2000; Creel, 2005; DeVries et al., 2003; 
Fair and Becker, 2000; Foley et al., 2001; Moberg, 2000; Relyea, 2005a; 
2005b, Romero, 2004; Sih et al., 2004).

Strandings Associated With Active Sonar

    Several sources have published lists of mass stranding events of 
cetaceans in an attempt to identify relationships between those 
stranding events and military active sonar (Hildebrand, 2004; IWC, 
2005; Taylor et al., 2004). For example, based on a review of stranding 
records between 1960 and 1995, the International Whaling Commission 
(2005) identified ten mass stranding events and 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 MF active sonar and 
most involved beaked whales.
    Over the past 12 years, there have been five stranding events 
coincident with military MF active sonar use in which exposure to sonar 
is believed by NMFS and the Navy to have been a contributing factor to 
strandings: Greece (1996); the Bahamas (2000); Madeira (2000); Canary 
Islands (2002); and Spain (2006). NMFS refers the reader to Cox et al. 
(2006) for a summary of common features shared by the strandings events 
in Greece (1996), Bahamas (2000), Madeira (2000), and Canary Islands 
(2002); and Fernandez et al., (2005) for an additional summary of the 
Canary Islands 2002 stranding event. Additionally, in 2004, during the 
Rim of the Pacific (RIMPAC) exercises, between 150 and 200 usually 
pelagic melon-headed whales occupied the shallow waters of the Hanalei 
Bay, Kaua'i, Hawaii for over 28 hours. NMFS determined that the mid-
frequency

[[Page 872]]

sonar was a plausible, if not likely, contributing factor in what may 
have been a confluence of events that led to the Hanalei Bay stranding. 
A number of other stranding events coincident with the operation of MF 
active sonar including the death of beaked whales or other species 
(minke whales, dwarf sperm whales, pilot whales) have been reported; 
however, the majority have not been investigated to the degree 
necessary to determine the cause of the stranding and only one of these 
exercises was conducted by the U. S. Navy.

Potential for Stranding From LFA Sonar

    There is no empirical evidence of strandings of marine mammals 
associated with the employment of SURTASS LFA sonar since its use began 
in the early 2000s. Moreover, the system acoustic characteristics 
differ between LF and MF sonars: LFA sonars use frequencies generally 
below 1,000 Hz, with relatively long signals (pulses) on the order of 
60 sec; while MF sonars use frequencies greater than 1,000 Hz, with 
relatively short signals on the order of 1 sec.
    As discussed previously, Cox et al. (2006) provided a summary of 
common features shared by the strandings events in Greece (1996), 
Bahamas (2000), and Canary Islands (2002). These included deep water 
close to land (such as offshore canyons), presence of an acoustic 
waveguide (surface duct conditions), and periodic sequences of 
transient pulses (i.e., rapid onset and decay times) generated at 
depths less than 32.8 ft (10 m) by sound sources moving at speeds of 
2.6 m/s (5.1 knots) or more during sonar operations (D'Spain et al., 
2006). These features do not relate to LFA sonar operations. First, the 
SURTASS LFA sonar vessel operates with a horizontal line array of 
4,921ft (1,500 m) length at depths below 492 ft (150 m) and a vertical 
line array (LFA sonar source) at depths greater than 328 ft (100 m). 
Second, the Navy will not operate SURTASS LFA sonar within 22 km (13. 
mi; 11.8 nm) of any coastline. For these reasons, SURTASS LFA sonar 
cannot be operated in deep water that is close to land. Also, the LFA 
sonar signal is transmitted at depths well below 32.8 ft (10 m). While 
there was an LF component in the Greek stranding in 1996, only MF 
components were present in the strandings in the Bahamas in 2000, 
Madeira 2000, and Canaries in 2002. The International Council for the 
Exploration of the Sea (ICES) in its ``Report of the Ad-Hoc Group on 
the Impacts of Sonar on Cetaceans and Fish'' raised the same issues as 
Cox et al., (2006) stating that the consistent association of MF sonar 
in the Bahamas, Madeira, and Canary Islands strandings suggest that it 
was the MF component, not the LF component, in the NATO sonar that 
triggered the Greek stranding of 1996 (ICES, 2005). The ICES (2005) 
report concluded that no strandings, injury, or major behavioral change 
have been associated with the exclusive use of LF sonar.

Concurrent Use of LF and MF Active Sonar

    The environmental impacts of the SURTASS LFA sonar system, 
including the potential for synergistic and cumulative effects with MF 
active sonar operation, has been addressed in detail in the Navy's 
application and the SURTASS LFA sonar 2011 DSEIS/SOEIS. NMFS will not 
consider the authorization of take of marine mammals incidental to the 
operation of MF active sonar in this document because NMFS has already 
separately authorized the incidental take associated with these 
activities. NMFS has considered more specifically the manner in which 
LFA sonar and MFAS may interact in a multi-strike group exercise with 
respect to the potential to impact marine mammals in a manner not 
previously considered.
    Tactical and technical considerations dictate that the LFA sonar 
ship would typically be tens of miles from the MF active sonar ship 
when using active sonar. It is unlikely, but remotely possible, that 
both LF and MF active sonar would be active at exactly the same time 
during a major exercise. Based on the differing operating 
characteristics of each sonar (pulse length, duty cycle, etc.), the 
percentage of overlap during concurrent MF and LF active sonar 
operations is approximately 0.017 percent. In the unlikely event that 
both systems were transmitting simultaneously, the likelihood of more 
than a relatively small number of individual marine mammals being 
physically present at a time, location, and depth to be able to receive 
both LF and MF active sonar signals at levels of concern at the same 
time is even smaller as the sound from both signals would have 
attenuated when they reached the marine mammal in question, so even a 
simultaneous exposure would not be at the full signal of either system. 
Additionally, only a few species have maximum sensitivity to both the 
low and middle frequencies.

Potential Effects of Vessel Movement and Collisions

    Vessel movement in the vicinity of marine mammals has the potential 
to result in either a behavioral response or a direct physical 
interaction. Both scenarios are discussed below.

Behavioral Responses to Vessel Movement

    There are limited data concerning marine mammal behavioral 
responses to vessel traffic and vessel noise, and a lack of consensus 
among scientists with respect to what these responses mean or whether 
they result in short-term or long-term adverse effects. In those cases 
where there is a busy shipping lane or where there is a large amount of 
vessel traffic, marine mammals may experience acoustic masking 
(Hildebrand, 2005) if they are present in the area (e.g., killer whales 
in Puget Sound; Foote et al., 2004; Holt et al., 2008). In cases where 
vessels actively approach marine mammals (e.g., whale watching or 
dolphin watching boats), scientists have documented that animals 
exhibit altered behavior such as increased swimming speed, erratic 
movement, and active avoidance behavior (Bursk, 1983; Acevedo, 1991; 
Baker and MacGibbon, 1991; Trites and Bain, 2000; Williams et al., 
2002; Constantine et al., 2003), reduced blow interval (Ritcher et al., 
2003), disruption of normal social behaviors (Lusseau, 2003; 2006), and 
the shift of behavioral activities which may increase energetic costs 
(Constantine et al., 2003; 2004). A detailed review of marine mammal 
reactions to ships and boats is available in Richardson et al. (1995). 
For each of the marine mammal taxonomy groups, Richardson et al. (1995) 
provides the following assessment regarding cetacean reactions to 
vessel traffic:
    Toothed whales: ``In summary, toothed whales sometimes show no 
avoidance reaction to vessels, or even approach them. However, 
avoidance can occur, especially in response to vessels of types used to 
chase or hunt the animals. This may cause temporary displacement, but 
we know of no clear evidence that toothed whales have abandoned 
significant parts of their range because of vessel traffic.''
    Baleen whales: ``When baleen whales receive low-level sounds from 
distant or stationary vessels, the sounds often seem to be ignored. 
Some whales approach the sources of these sounds. When vessels approach 
whales slowly and non-aggressively, whales often exhibit slow and 
inconspicuous avoidance maneuvers. In response to strong or rapidly 
changing vessel noise, baleen whales often interrupt their normal 
behavior and swim rapidly away. Avoidance is especially strong when a 
boat heads directly toward the whale.''

[[Page 873]]

    Behavioral responses to stimuli are complex and influenced to 
varying degrees by a number of factors, such as species, behavioral 
contexts, geographical regions, source characteristics (moving or 
stationary, speed, direction, etc.), prior experience of the animal and 
physical status of the animal. For example, studies have shown that 
beluga whales' reactions varied when exposed to vessel noise and 
traffic. In some cases, naive beluga whales exhibited rapid swimming 
from ice-breaking vessels up to 80 km (49.7 mi) away, and showed 
changes in surfacing, breathing, diving, and group composition in the 
Canadian high Arctic where vessel traffic is rare (Finley et al., 
1990). In other cases, beluga whales were more tolerant of vessels, but 
responded differentially to certain vessels and operating 
characteristics by reducing their calling rates (especially older 
animals) in the St. Lawrence River where vessel traffic is common 
(Blane and Jaakson, 1994). In Bristol Bay, Alaska, beluga whales 
continued to feed when surrounded by fishing vessels and resisted 
dispersal even when purposefully harassed (Fish and Vania, 1971).
    In reviewing more than 25 years of whale observation data, Watkins 
(1986) concluded that whale reactions to vessel traffic were ``modified 
by their previous experience and current activity: habituation often 
occurred rapidly, attention to other stimuli or preoccupation with 
other activities sometimes overcame their interest or wariness of 
stimuli.'' Watkins noticed that over the years of exposure to ships in 
the Cape Cod area, minke whales changed from frequent positive interest 
(e.g., approaching vessels) to generally uninterested reactions; fin 
whales changed from mostly negative (e.g., avoidance) to uninterested 
reactions; right whales apparently continued the same variety of 
responses (negative, uninterested, and positive responses) with little 
change; and humpbacks dramatically changed from mixed responses that 
were often negative to reactions that were often strongly positive. 
Watkins (1986) summarized that ``whales near shore, even in regions 
with low vessel traffic, generally have become less wary of boats and 
their noises, and they have appeared to be less easily disturbed than 
previously. In particular locations with intense shipping and repeated 
approaches by boats (such as the whale-watching areas of Stellwagen 
Bank), more and more whales had positive reactions to familiar vessels, 
and they also occasionally approached other boats and yachts in the 
same ways.''
    Although the radiated sound from Navy vessels will be audible to 
marine mammals over a large distance, it is unlikely that animals will 
respond behaviorally (in a manner that NMFS would consider MMPA 
harassment) to low-level distant shipping noise as the animals in the 
area are likely to be habituated to such noises (Nowacek et al., 2004). 
In light of these facts, NMFS does not expect the Navy's vessel 
movements to result in Level B harassment.

Vessel Strike

    Commercial and Navy 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 14.9 mph (24.1 km/hr; 13 kts).
    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 kts. 
The majority (79 percent) of these strikes occurred at speeds of 13 kts 
or greater. The average speed that resulted in serious injury or death 
was 18.6 kts. Pace and Silber (2005) found that the probability of 
death or serious injury increased rapidly with increasing vessel speed. 
Specifically, the predicted probability of serious injury or death 
increased from 45 percent to 75 percent as vessel speed increased from 
10 to 14 kts, and exceeded 90 percent at 17 kts. Higher speeds during 
collisions result in greater force of impact, but higher speeds also 
appear to increase the chance of severe injuries or death by pulling 
whales toward the vessel. Computer simulation modeling showed that 
hydrodynamic forces pulling whales toward the vessel hull increase with 
increasing speed (Clyne, 1999; Knowlton et al., 1995).
    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.
    The Navy's proposed operation of up to four SURTASS LFA sonar 
vessels world-wide is relatively small in scale compared to the number 
of commercial ships transiting at higher speeds in the same areas on an 
annual basis. The probability of vessel and marine mammal interactions 
occurring during SURTASS LFA operations is unlikely due to the 
surveillance vessel's slow operational speed, which is typically 3.4 
mph (5.6 km/hr; 3 kts). Outside of operations, each vessel's cruising 
speed would be approximately 11.5 to 14.9 mph (18.5 to 24.1 km/hr; 10 
to 13 kts) which is generally below the speed at which studies have 
noted reported increases of marine mammal injury or death (Laist et 
al., 2001). Second, the Navy would restrict the operation of SURTASS 
LFA vessels at a distance of 1 km (0.62 mi; 0.54 nmi) seaward of the 
outer perimeter of any OBIA designated for marine mammals during a 
specified period, further minimizing the potential for marine mammal 
interactions. Also, the Navy would not operate SURTASS

[[Page 874]]

LFA vessels a distance of 22 km (13. mi; 11.8 nmi) or less of any 
coastline, including islands, thus operating in offshore coastal areas 
with lower densities of marine mammals would minimize adverse impacts.
    As a final point, the SURTASS LFA surveillance vessels have a 
number of other advantages for avoiding ship strikes as compared to 
most commercial merchant vessels, including the following: The T-AGOS 
ships have their bridges positioned forward of the centerline, offering 
good visibility ahead of the bow and good visibility aft to visually 
monitor for marine mammal presence; lookouts posted during operations 
scan the ocean for marine mammals and must report visual alerts of 
marine mammal presence to the Deck Officer; Navy lookouts receive 
extensive training that covers the fundamentals of visual observing for 
marine mammals and information about marine mammals and their 
identification at sea; and SURTASS LFA vessels travel at 3-4 kts 
(approximately 3.4 mph; 5.6 km/hr) with deployed arrays. For a thorough 
discussion of mitigation measures, please see the Mitigation section 
later in this document.

Anticipated Effects on Marine Mammal Habitat

    The Navy's proposed routine testing and training, as well as 
military operations using SURTASS LFA sonar, could potentially affect 
marine mammal habitat through the introduction of pressure and sound 
into the water column, which in turn could impact prey species of 
marine mammals.
    Based on the following information and the supporting information 
included in the Navy's application, the 2001 FOEIS/EIS, the 2007 FSEIS, 
and the 2011 DSEIS/SOEIS, NMFS has preliminarily determined that 
SURTASS LFA sonar operations will not have significant or long-term 
impacts on marine mammal habitat. Unless the sound source is stationary 
and/or continuous over a long duration in one area, the effects of the 
introduction of sound into the environment are generally considered to 
have a less severe impact on marine mammal habitat than the physical 
alteration of the habitat. Marine mammals may be temporarily displaced 
from areas where SURTASS LFA operations are occurring, but the area 
will likely be utilized again after the activities have ceased. A 
summary of the conclusions are included in subsequent sections.

Compliance With Maritime Law

    Use of SURTASS LFA sonar entails the periodic deployment of 
acoustic transducers and receivers into the water column from ocean-
going ships. The Navy deploys SURTASS LFA sonar from ocean surveillance 
ships that are U.S. Coast Guard-certified for operations and operate in 
accordance with all applicable federal, international, and U.S. Navy 
rules and regulations related to environmental compliance, especially 
for discharge of potentially hazardous materials. SURTASS LFA sonar 
ships comply with all requirements of the Clean Water Act of 1972 (CWA; 
33 U.S.C. section 1251 et seq.) and Act to Prevent Pollution from Ships 
(APPS; 33 U.S.C. subsections 1905-1915). SURTASS LFA vessel movements 
are not unusual or extraordinary and are part of routine operations of 
seagoing vessels. Therefore, no discharges of pollutants regulated 
under the APPS or CWA will result from the operation of the sonar 
systems nor will any unregulated environmental impacts from the 
operation of the SURTASS LFA sonar vessels occur.

Geographic Restrictions

    The Navy has proposed that the sound field does not exceed 180 dB 
re: 1 [micro]Pa at 1 m (i.e., a mitigation zone) within 22 km (13. mi; 
11.8 nmi) of any coastline, including islands, or within proposed OBIAs 
during biologically important seasons, during the conduct of SURTASS 
LFA operations.

Critical Habitat

    Of the designated critical habitat for marine mammals, four areas 
are at a distance sufficient from shore to potentially be affected by 
SURTASS LFA sonar. They are the critical habitat for the north Atlantic 
right whale (NARW), north Pacific right whale (NPRW), Hawaiian monk 
seal, and Steller sea lion. The Navy proposes that the sound field 
would not exceed 180 dB re: 1 [micro]Pa at 1 m in the areas designated 
as critical habitat for the north Atlantic right whale, north Pacific 
right whale, and the Hawaiian monk seal.
    For NARW critical habitat, the Navy has proposed an OBIA that 
encompasses the critical habitats of the North Atlantic right whale in 
Georges Bank (OBIA 1); Roseway Basin right whale Conservation 
Area (OBIA 2); in portions of the Gulf of Maine including 
Stellwagen Bank National Marine Sanctuary, that are located outside of 
22 km (13. mi; 11.8 nmi) (OBIA 3); and the southeastern U.S. 
Right whale Seasonal critical habitat (OBIA 4). In 2008, NMFS 
designated two areas of critical habitat for the NPRW, one in the 
Bering Sea where the Navy proposes to not conduct SURTASS LFA sonar 
operations. For the other designated area for critical habitat in the 
Gulf of Alaska, the Navy has proposed an OBIA (5) that bounds 
the designated critical habitat for the species.
    Much of the proposed critical habitat for Hawaiian monk seals is 
within 22 km (13. mi; 11.8 nmi) of any shoreline and there is no 
proposed OBIA that encompasses the entirety of Hawaiian monk seal 
critical habitat. However, the Navy has proposed an OBIA (16) 
that encompasses the Penguin Bank portion of the Hawaiian Islands 
Humpback Whale National Marine Sanctuary.
    There is no proposed OBIA that encompasses designated critical 
habitat for Steller sea lions. Much of the critical habitat for the 
Steller sea lion is located in the Bering Sea, where SURTASS LFA sonar 
will not operate. Although it is possible that the sonar will be 
operated in the western Gulf of Alaska where the eastern critical 
habitat for the Steller sea lion is located and some of that habitat 
lies outside of 22 km (13. mi; 11.8 nmi) from shore, the water depth in 
which the habitat is found is sufficiently shallow that it is unlikely 
that the Navy would operate sonar in the vicinity of that critical 
habitat.
    Both the Navy and NMFS will consult with NMFS on effects on 
critical habitat pursuant to section 7 of the ESA.

Marine Protected Areas (MPA)

    Within the National System of MPAs, seven formally recognized areas 
are in potential SURTASS LFA sonar operating areas because a portion of 
the area or its seaward boundary is located beyond 22 km (13. mi; 11.8 
nmi) from the coastline. These MPAs are: Stellwagen Bank National 
Marine Sanctuary (NMS); Olympic Coast NMS; Gulf of the Farallones NMS; 
Monterey Bay NMS; Cordell Bank NMS; Hawaiian Islands Humpback Whale 
NMS; and Papahanaumokuakea Marine National Monument. The Navy has 
proposed not to operate SURTASS LFA sonar in specified areas of 
National Marine Sanctuaries during biologically important seasons (see 
OBIA section discussed later in this document).
    The proposed SURTASS LFA operations are not anticipated to have any 
permanent impact on habitats used by the marine mammals in the proposed 
operational areas, including the food sources they use (i.e., fish and 
invertebrates). Additionally, no physical damage to any habitat is 
anticipated as a result of conducting the proposed SURTASS LFA 
operations. While it is

[[Page 875]]

anticipated that the specified activity may result in marine mammals 
avoiding certain areas due to temporary ensonification, this impact to 
habitat is temporary and reversible and was considered in further 
detail earlier in this document, as behavioral modification. The main 
impact associated with the proposed activity will be temporarily 
elevated noise levels and the associated direct effects on marine 
mammals, previously discussed in this notice.

Anticipated Impacts on Fish

    The Navy's DSEIS/SOEIS includes a detailed discussion of the 
effects of active sonar on marine fish and several studies on the 
effects of both Navy sonar and seismic airguns that are relevant to 
potential effects of SURTASS LFA sonar on osteichthyes (bony fish). In 
the most pertinent of these, the Navy funded independent scientists to 
analyze the effects of SURTASS LFA sonar on fish (Popper et al., 2005a, 
2007; Halvorsen et al., 2006) and on the effects of SURTASS LFA sonar 
on fish physiology (Kane et al., 2010).
    Several studies on the effects of SURTASS LFA sonar sounds on three 
species of fish (rainbow trout, channel catfish, and hybrid sunfish) 
examined long-term effects on sensory hair cells of the ear. In all 
species, even up to 96 hours post-exposure, there were no indications 
of damage to sensory cells (Popper et al., 2005a, 2007; Halvorsen et 
al., 2006). Recent results from direct pathological studies of the 
effects of LFA sounds on fish (Kane et al., 2010) provide evidence that 
SURTASS LFA sonar sounds at relatively high received levels (up to 193 
dB re: 1 [mu]Pa at 1 m) have no pathological effects or short- or long-
term effects to ear tissue on the species of fish that have been 
studied.

Anticipated Impacts on Invertebrates

    Among invertebrates, only cephalopods (octopus and squid) and 
decapods (lobsters, shrimps, and crabs) are known to sense LF sound 
(Packard et al., 1990; Budelmann and Williamson, 1994; Lovell et al., 
2005; Mooney et al., 2010). Popper and Schilt (2008) stated that, like 
fish, some invertebrate species produce sound, possibly using it for 
communications, territorial behavior, predator deterrence, and mating. 
Well known sound producers include the lobster (Panulirus spp.) (Latha 
et al., 2005), and the snapping shrimp (Alpheus heterochaelis) 
(Herberholtz and Schmitz, 2001).
    Andre et al. (2011) exposed four cephalopod species (Loligo 
vulgaris, Sepia officinalis, Octopus vulgaris, and Ilex coindetii) to 
two hours of continuous sound from 50 to 400 Hz at 157  5 
dB re: 1 [mu]Pa. They reported lesions to the sensory hair cells of the 
statocysts of the exposed animals that increased in severity with time, 
suggesting that cephalopods are particularly sensitive to low-frequency 
sound. However, the Navy notes in the DSEIS/SOEIS (Chapter 3-6) that 
the authors failed to elaborate that there were no anthropogenic 
sources to which animals might be exposed with characteristics similar 
to those used in their study. The time sequence of exposure from low-
frequency sources in the open ocean would be about once every 10 to 15 
min for SURTASS LFA. Therefore, the study's sound exposures were longer 
in duration and higher in energy than any exposure a marine mammal 
would likely ever receive and acoustically very different than a free 
field sound to which animals would be exposed in the real world. Given 
the lack of data on hearing thresholds of cephalopods, SURTASS LFA 
sonar operations could only have a lasting impact on these animals if 
they are within a few tens of meters from the source. In conclusion, 
NMFS does not expect any short- or long-term effects to marine mammal 
food resources from SURTASS LFA sonar activities.

Proposed Mitigation

    In order to issue an incidental take authorization (ITA) 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.'' The NDAA of 2004 amended 
section 101(a)(5)(A) of the MMPA 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 activities described in the SURTASS 
LFA sonar application are considered military readiness activities.
    NMFS reviewed the proposed SURTASS LFA sonar activities and the 
proposed mitigation measures as described in the Navy's application to 
determine if they would result in the least practicable adverse effect 
on marine mammals, which includes a careful balancing of the likely 
benefit of any particular measure to the marine mammals with the likely 
effect of that measure on personnel safety, practicality of 
implementation, and impact on the effectiveness of the ``military 
readiness activity.''
    To reduce the potential for impacts from acoustic stimuli 
associated with the Navy's SURTASS LFA sonar activities, the Navy has 
proposed to implement the following mitigation measures for marine 
mammals:
    (1) LFA sonar mitigation zone--LF sources transmissions are 
suspended if the Navy detects marine mammals within the mitigation 
zones by any of the following detection methods:
    (a) Visual monitoring;
    (b) Passive acoustic monitoring;
    (c) Active acoustic monitoring;
    (2) Geographic restrictions in the following areas:
    (a) Offshore Biologically Important Areas (OBIAs);
    (b) Coastal Standoff Zone.
    Additionally, as with the previous rulemaking, NMFS proposes to 
include additional operational restrictions for SURTASS LFA sonar 
operations:
    (1) Additional 1-km buffer around the LFA sonar mitigation zone; 
and
    (2) Additional 1-km buffer around an OBIA perimeter.
    Both the Navy's proposed mitigation and NMFS' additional proposed 
mitigation are discussed below this section.

LFA Sonar Mitigation Zone

    The Navy has proposed in its application to establish a 180-dB (RL) 
isopleth LFA sonar mitigation zone around the surveillance vessel. If a 
marine mammal approaches or enters the LFA sonar mitigation zone, the 
Navy would implement a suspension of SURTASS LFA sonar transmissions.
    Prior to commencing and during SURTASS LFA transmissions, the Navy 
will determine the propagation of LFA sonar signals in the ocean and 
the distance from the SURTASS LFA sonar source to the 180-dB isopleth 
(See Description of Real-Time SURTASS LFA Sonar Sound Field Modeling 
section). The 180-dB isopleth will define the LFA sonar mitigation zone 
for marine mammals around the surveillance vessel.
    The Navy modeling of the sound field in near-real time conditions 
provides the information necessary to modify SURTASS LFA operations, 
including the delay or suspension of LFA transmissions. Acoustic model 
updates are nominally made every 12 hr, or more frequently when 
meteorological or oceanographic conditions change. If the sound field 
criteria were exceeded, the sonar operator would notify the Officer in 
Charge (OIC), who would order the delay or suspension of transmissions. 
If it were predicted that the SPLs would

[[Page 876]]

exceed the criteria within the next 12 hr period, the OIC would also be 
notified in order to take the necessary action to ensure that the sound 
field criteria would not be exceeded.

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

    As an added measure, NMFS again proposes to require a ``buffer 
zone'' that extends an additional 1 km (0.62 mi; 0.54 nm) beyond the 
180-dB isopleth LFA sonar mitigation zone. This buffer coincides with 
the full detection range of the HF/M3 active sonar for mitigation 
monitoring (approximately 2 to 2.5 km; 1.2 to 1.5 mi; 1.1 to 1.3 nmi). 
Thus, the 180-dB isopleth for the LFA sonar mitigation zone, plus NMFS' 
1-km (0.54 nm) buffer zone would comprise the entire mitigation zone 
for SURTASS LFA sonar operations, wherein suspension of transmissions 
would occur if a marine mammal approaches or enters either zone. The 
Navy notes in its application that this additional mitigation is 
practicable and it would adhere to this additional measure if required 
in the proposed rule.
    In addition to establishing a 180-dB (RL) isopleth LFA sonar 
mitigation zone around the surveillance vessel the Navy has also 
proposed to establish a mitigation zone for human divers at 145 dB re: 
1 [micro]Pa at 1 m around all known human commercial and recreational 
diving sites. Although this geographic restriction is intended to 
protect human divers, it will also reduce the LF sound levels received 
by marine mammals located in the vicinity of known dive sites.

Visual Mitigation Monitoring

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

Passive Acoustic Mitigation Monitoring

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

Active Acoustic Mitigation Monitoring

    HF active acoustic monitoring uses the HF/M3 sonar to detect, 
locate, and track marine mammals that could pass close enough to the 
SURTASS LFA sonar array to enter the LFA sonar mitigation or buffer 
zones. HF/M3 acoustic monitoring begins 30 min before the first SURTASS 
LFA sonar transmission of a given mission is scheduled to commence and 
continues until the Navy terminates the transmissions.
    If the HF/M3 sonar operator detects a marine mammal contact outside 
the LFA sonar mitigation zone or buffer zones, the HF/M3 sonar operator 
shall determine the range and projected track of the marine mammal. If 
the operator determines that the marine mammal will pass within the LFA 
sonar mitigation or buffer zones, he/she shall notify the OIC. The OIC 
then immediately orders the delay or suspension of transmissions when 
the animal is predicted to enter the LFA sonar mitigation or buffer 
zones.
    If the HF/M3 sonar operator detects a marine mammal within the LFA 
mitigation or buffer zones, he/she shall

[[Page 877]]

notify the OIC who will immediately order the delay or suspension of 
transmissions. The HF/M3 sonar operator will record all contacts of 
marine mammals into the log.
    Prior to full-power operations of the HF/M3 active sonar, the Navy 
will ramp up the HF/M3 sonar power level over a period of 5 min from 
the source level of 180 dB re 1 [mu]Pa at 1 m in 10-dB increments until 
the system attains full power (if required) to ensure that there are no 
inadvertent exposures of marine mammals to received levels greater than 
180 dB re 1 [mu]Pa from the HF/M3 sonar. The Navy will not increase the 
HF/M3 sonar source level if any of the three monitoring programs detect 
a marine mammal during ramp-up. Ramp-up may continue once marine 
mammals are no longer detected by any of the three monitoring programs.
    Prior to any SURTASS LFA sonar calibrations or testing that are not 
part of regular SURTASS LFA sonar transmissions, the Navy will ramp up 
the HF/M3 sonar power level over a period of 5 min from the source 
level of 180 dB re 1 [mu]Pa at 1 m in 10-dB increments until the system 
attains full power. The Navy will not increase the HF/M3 source level 
if any of the three monitoring programs detect a marine mammal during 
ramp-up. Ramp-up may continue once marine mammals are no longer 
detected by any of the three monitoring programs.
    In situations where the HF/M3 sonar system has been powered down 
for more than 2 min, the Navy will ramp up the HF/M3 sonar power level 
over a period of 5 min from the source level of 180 dB re 1 [mu]Pa at 1 
m in 10-dB increments until the system attains full power.

Past Mitigation Monitoring Under the Previous Rules

    For the first four LOA periods under the 2007 rule, the Navy has 
reported a total of eight visual sightings, four passive acoustic 
detections, and 29 HF/M3 active sonar detections (DoN, 2008; 2009a; 
2010; 2011) leading to mitigation protocols of suspensions/delays of 
transmissions in a total of 70 missions.
    During the 2002-2007 rule period, the Navy reported a total of four 
visual sightings, no passive acoustic detections, and 101 active HF/M3 
active sonar detections leading to mitigation protocols of suspensions/
delays of transmissions (DoN, 2007a; 2007b) in a total of 58 missions. 
However, these data sets involving marine species are too small to 
support any meaningful analyses, such as determining if there are any 
differences in detection during the time when LFA sonar is active 
versus when it is inactive.

Geographic Restrictions

    As noted above, the Navy has proposed two types of geographic 
restrictions for SURTASS LFA operations in the LOA application: (1) 
establishing OBIAs for marine mammal protection and restricting SURTASS 
LFA sonar operations within these designated areas such that the 
SURTASS LFA sonar-generated sound field will not exceed 180 dB re: 1 
[mu]Pa (RL); and (2) restricting SURTASS LFA sonar operations within 22 
km (13. mi; 11.8 nmi) of any coastline, including islands.

Offshore Biologically Important Areas

    As with the previous SURTASS LFA sonar rulemakings, the Navy's 
application again proposed establishing offshore biologically important 
areas OBIAs for marine mammal protection. In preparation for this rule 
making, NMFS developed a more systematic process for selecting, 
assessing, and designating OBIAs for SURTASS LFA sonar.
    First, NMFS developed screening criteria to help initially select 
potential areas and then determine an area's eligibility for 
consideration as an OBIA nominee. These OBIA screening criteria 
included:
    (1) Areas with:
    (a) High densities of marine mammals; or
    (b) Known/defined breeding/calving grounds, foraging grounds, 
migration routes; or
    (c) Small, distinct populations of marine mammals with limited 
distributions; and
    (2) Areas that are outside of the coastal standoff distance and 
within potential operational areas for SURTASS LFA (i.e., greater than 
22 km (13.6 mi; 12 nmi) from any shoreline and not in polar regions).
    NMFS used the screening criteria to review 403 existing and 
potential marine protected areas based on the World Database on 
Protected Areas (WDPA) (IUCN and UNEP, 2009), Holt (2005), and prior 
SURTASS LFA sonar OBIAs to produce a preliminary list of 27 OBIA 
nominees.
    NMFS next convened an expert review panel of biologists 
knowledgeable about potentially affected marine mammal biologically 
important areas. This panel consisted of subject matter experts (SME), 
each with expertise in geographic regions including the Atlantic Ocean, 
Pacific Ocean, Mediterranean Sea, Indian Ocean/Southeast Asia, and East 
Africa. The SMEs provided their individual analyses of NMFS' 
preliminary candidates as potential marine mammal OBIAs in waters where 
the Navy potentially could use the SURTASS LFA sonar systems and 
provided additional recommendations for other OBIAs. This resulted in a 
total number of 73 potential OBIAs. These areas were further screened 
for sufficient scientific support, resulting in 45 potential OBIAs.
    Although not part of its initial screening criteria, consideration 
of marine mammal hearing frequency sensitivity led NMFS to screen out 
areas that qualified solely on the basis of their importance for mid- 
or high-frequency hearing specialists. The LFA sound source is well 
below the range of best hearing sensitivity for most MF and HF 
odontocete hearing specialists. This means, for example, for harbor 
porpoises, that a sound with a frequency less than 1 kHz needs to be 
significantly louder (more than 40 dB louder) than a sound in their 
area of best sensitivity (around 100 kHz) in order for them to hear it. 
Additionally, during the 1997 to 1998 SURTASS LFA Sonar Low Frequency 
Sound Scientific Research Program (LFS SRP), numerous odontocete and 
pinniped species (i.e., MF and HF hearing specialists) were sighted in 
the vicinity of the sound exposure tests and showed no immediately 
obvious responses or changes in sighting rates as a function of source 
conditions, which likely produced received levels similar to those that 
produced minor short-term behavioral responses in the baleen whales 
(i.e., LF hearing specialists). NMFS believes that MF and HF odontocete 
hearing specialists have such reduced sensitivity to the LFA source 
that limiting ensonification in OBIAs for those animals would not 
afford protection beyond that which is already incurred by implementing 
a shutdown when any marine mammal enters the LFA mitigation and buffer 
zones. Consideration of this additional information resulted in a list 
of 22 final OBIA nominees for the Navy's consideration.
    The 22 areas are: (1) Georges Bank, year round; (2) Roseway Basin 
Right Whale Conservation Area, June through December; (3) the Great 
South Channel, U.S. Gulf of Maine, and Stellwagen Bank NMS, January 1 
to November 14; (4) the Southeastern U.S. Right Whale Seasonal Habitat, 
November 15 to January 15; (5) the North Pacific Right Whale Critical 
Habitat, March through August; (6) Silver Bank and Navidad Bank, 
December through April; (7) the coastal waters of Gabon, Congo and

[[Page 878]]

Equatorial Guinea, June through October; (8) the Patagonian Shelf 
Break, year round; (9) Southern Right Whale Seasonal Habitat, May 
through December; (10) the central California National Marine 
Sanctuaries, June through November; (11) the Antarctic Convergence 
Zone, October through March; (12) Piltun and Chayvo offshore feeding 
grounds in the Sea of Okhotsk, June through November; (13) the coastal 
waters off Madagascar, July through September for humpback whale 
breeding and November through December for migrating blue whales; (14) 
Madagascar Plateau, Madagascar Ridge, and Walters Shoal, November 
through December; (15) the Ligurian-Corsican-Provencal Basin and 
Western Pelagos Sanctuary in the Mediterranean Sea, July to August; 
(16) Hawaiian Islands Humpback Whale NMS and Penguin Bank, November 
through April; (17) the Costa Rica Dome, year round; (18) the Great 
Barrier Reef Between 16[deg] S and 21[deg] S, May through September; 
(19) the Bonney Upwelling on the west coast of Australia, December 
through May; (20) the Northern Bay of Bengal and Head of Swatch-of-No-
Ground, year round; (21) the Olympic Coast NMS (within 23 nmi (26.5 m; 
42.6 km) of the coast from 47[deg]07' N to 48[deg]30' N latitude), 
December, January, March, and May and the Prairie, Barkley Canyon, and 
Nitnat Canyon, June through September; and (22) an area within the 
Southern California Bight, June through November for blue whales, 
December through May for gray whales, year-round for all other species.
    The Navy agreed that these areas met NMFS' criteria and based on 
its practicability assessment pursuant to the MMPA, the Navy proposed 
21 of the 22 sites in its application. An area within the Southern 
California Bight, specifically an area including Tanner and Cortes 
Banks (see section 4.5.2.3 for boundary information) from June through 
November, met the criteria as a concentrated area for blue whales based 
on predictive modeling (Barlow et al., 2009) or as a foraging area 
based on a 2000-2004 study of blue whale calls (Oleson, Calambokidis, 
Barlow, & Hildebrand, 2007). However, the Navy concluded that the 
underlying data cover a short time period and the dynamic nature of 
blue whale distribution and the variability of prey abundance make it 
difficult to assign any permanence to this area as one of blue whale 
concentration. The Navy determined that avoiding this area was 
operationally impracticable as much of the OBIA is within the existing 
Southern California (SOCAL) Range Complex which plays a vital part in 
ensuring military readiness. The training that occurs in the SOCAL 
Range Complex includes antisubmarine warfare (ASW) training and the 
SOCAL Range Complex provides the uneven, mountainous underwater 
topography that is essential to such training, because it is similar to 
the kind of underwater topography that submarines use to hide or mask 
their presence. NMFS preliminarily concurs with the Navy's 
practicability assessment.
    Based on the Navy's practicability evaluation, NMFS proposes to 
designate these 21 sites as OBIAs for LFA sonar. NMFS refers the 
readers to Table 2 in the Navy's application and Chapter 4 and Appendix 
D-8 of the Navy's 2011 DSEIS/SOEIS for more detailed information on the 
specific justification for each OBIA, the locations, and geographic 
boundaries of the proposed OBIAS.

NMFS' Additional 1-km Buffer Zone Around an OBIA Perimeter

    NMFS also proposes an OBIA ``buffer'' requirement for the Navy that 
would restrict the operation of SURTASS LFA sonar so that the SURTASS 
LFA sonar sound field does not exceed 180 dB re: 1 [mu]Pa at a distance 
of 1 km (0.62 mi; 0.54 nmi) seaward of the outer perimeter of any OBIA 
designated for marine mammals during the specified period. The Navy 
notes in its application that this additional mitigation is practicable 
and it would adhere to this additional measure if required in the 
proposed rule.
    OBIAs are mitigation measures for SURTASS LFA sonar and are based 
on the system's unique operating and physical characteristics and 
should not be assumed to be appropriate for other activities.

Coastal Standoff Zone

    The Navy has proposed to restrict SURTASS LFA sonar operations 
within 22 km (13. mi; 11.8 nmi) of any coastline, including islands 
such that the SURTASS LFA sonar-generated sound field will not exceed 
180 dB re: 1 [mu]Pa (RL) at that distance.

Operational Exception

    It may be necessary for SURTASS LFA transmissions to be at or above 
180 dB re 1 [mu]Pa (rms) within the boundaries of the designated 
SURTASS LFA sonar OBIAs, including operating within an OBIA, when: (1) 
Operationally necessary to continue tracking an existing underwater 
contact; or (2) operationally necessary to detect a new underwater 
contact within the OBIA. This exception will not apply to routine 
training and testing with the SURTASS LFA sonar systems.

Mitigation Conclusions

    NMFS has carefully evaluated the Navy's proposed mitigation 
measures 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 measure is expected to minimize 
adverse impacts to marine mammals;
     The proven or likely efficacy of the specific measure to 
minimize adverse impacts as planned; and
     The practicability of the measure for applicant 
implementation, including consideration of personnel safety, 
practicality of implementation, and impact on the effectiveness of the 
military readiness activity.
    In some cases, additional mitigation measures are proposed beyond 
those that the applicant proposed. 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 the 
accomplishment of one or more of the general goals listed below:
    (a) Avoidance or minimization of injury or death of marine mammals 
wherever possible (goals b, c, and d may contribute to this goal).
    (b) A reduction in the numbers of marine mammals (total number or 
number at biologically important time or location) exposed to received 
levels of LFA sonar or other activities expected to result in the take 
of marine mammals (this goal may contribute to goal a, above, or to 
reducing harassment takes only).
    (c) A reduction in the number of times (total number or number at 
biologically important time or location) individuals would be exposed 
to received levels of LFA sonar or other activities expected to result 
in the take of marine mammals (this goal may contribute to goal a, 
above, or to reducing harassment takes only).
    (d) A reduction in the intensity of exposures (either total number 
or number at biologically important time or location) to received 
levels of LFA sonar or other activities expected to result in the take 
of marine mammals (this goal may contribute to goal a,

[[Page 879]]

above, or to reducing the severity of harassment takes only).
    (e) Avoidance or minimization of adverse effects to marine mammal 
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--an increase in 
the probability of detecting marine mammals, thus allowing for more 
effective implementation of the mitigation (i.e., shutdown in the LFA 
mitigation and buffer zones).
    Based on our evaluation of the Navy's proposed measures, as well as 
other measures considered by NMFS or recommended by the public, NMFS 
has determined preliminarily that the Navy's proposed mitigation 
measures together with the additional mitigation measures proposed by 
NMFS provide the means of effecting the least practicable adverse 
impacts on marine mammals species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, while also considering personnel safety, practicality of 
implementation, and impact on the effectiveness of the military 
readiness activity. NMFS provides further details in the following 
section.
    NMFS believes that the shutdown in the LFA sonar mitigation and 
buffer zones, visual monitoring, passive acoustic monitoring, active 
acoustic monitoring using HF/M3 sonar with ramp-up procedures, and 
geographic restriction measures proposed will enable the Navy to: (1) 
Avoid Level A harassment of marine mammals; (2) Minimize the numbers of 
marine mammals exposed to SURTASS LFA sonar sound associated with TTS; 
and (3) Minimize the numbers taken specifically during times of 
important behaviors, such as feeding, migrating, calving, or breeding.
    TTS: The LFA sonar signal is not expected to cause TTS at received 
levels below 180 dB re: 1 [mu]Pa. In other words, the received level of 
the LFA sonar signal at approximately 1 km (0.62 mi; 0.54 nmi) from the 
vessel is 180 dB re: 1 [mu]Pa. Implementing an additional 1-km buffer 
zone increases the shutdown zone to approximately 2 km (1.2 mi; 1.1 
nmi) around the LFA sonar array and vessel will ensure that no marine 
mammals are exposed to an SPL greater than about 174 dB re: 1 [mu]Pa.
    The best information available indicates that effects from SPLs 
less than 180 dB re: 1 [mu]Pa will be limited to short-term, Level B 
behavioral Harassment affecting less than an average of 12 percent of 
the stocks present in an operational area annually for most affected 
species.
    PTS/Injury: In the case of SURTASS LFA sonar operations, NMFS does 
not expect marine mammals to be exposed to received sound levels that 
are high enough or long enough in duration to result in PTS. The Navy's 
standard protective measures indicate that they would ensure delay or 
suspension of SURTASS LFA sonar transmissions if any of the three 
monitoring programs detect a marine mammal entering the LFA mitigation 
and/or buffer zones i.e., within approximately two km (1.2 mi; 1.1 nmi) 
of the vessel. The proposed mitigation monitoring measures would allow 
the Navy to avoid exposing marine mammals to received levels of SURTASS 
LFA sonar or HF/M3 sonar sound that could result in injury (Level A 
harassment).
    Southall et al. (2007) proposed injury criteria for individual 
marine mammals exposed to non-pulsed sound types, which included 
discrete acoustic exposures from SURTASS LFA sonar. The proposed injury 
criteria for cetaceans are sound pressure levels (SPL) of 230 dB re: 1 
[mu]Pa and sound exposure levels (SEL) of 215 dB re: 1 [mu]Pa\2\-sec. 
Taking into account an 18-dB adjustment for the longer LFA signal in 
SEL units, the proposed injury criteria for cetaceans exposed to 
SURTASS LFA sonar signals would result in an SEL of 197 dB re: 1 
[mu]Pa\2\-sec (i.e., 215 - 18 = 197) (which converts to an SPL of 
approximately 182 dB re: 1 [mu]Pa). The Navy's criterion for estimating 
injury marine mammals is an SPL of 180 dB re: 1 [mu]Pa is lower than 
the injury criteria proposed by Southall et al. (2007). Thus, the 
probability of SURTASS LFA sonar transmissions (with mitigation) 
causing PTS in marine mammals is considered unlikely.
    The SPLs capable of potentially causing injury to an animal are 
well within approximately 1 km (0.62 mi; 0.54 nm) of the ship. 
Implementing a shutdown zone of approximately 2 km (1.2 mi; 1.1 nmi) 
around the LFA sonar array and vessel will ensure that no marine 
mammals are exposed to an SPL greater than about 174 dB re: 1 [mu]Pa. 
This is significantly lower than the 180-dB re: 1 [mu]Pa used for other 
acoustic projects for protecting marine mammals from injury.
    Serious injury is unlikely to occur unless a marine mammal is well 
within the 180-dB re: 1 [mu]Pa LFA sonar mitigation zone and close to 
the source. The closer a mammal is to the vessel, the more likely the 
Navy personnel will detect it by the three-part monitoring program 
leading to the immediate suspension of SURTASS LFA sonar operations.
    The Navy has operated SURTASS LFA sonar under NMFS regulations for 
the last nine years without any reports of injury or death. The 
evidence to date, including recent scientific reports and annual 
monitoring reports, and nine-year's worth of conducting SURTASS LFA 
operations further supports the conclusion that the potential for 
serious injury to occur is minimal.

Proposed Research

    The Navy sponsors significant research and monitoring projects for 
marine living resources to study the potential effects of its 
activities on marine mammals. These funding levels have increased in 
recent years to $31 million in FY 2009 and $32 million in FY 2010 for 
marine mammal research and monitoring activities at universities, 
research institutions, federal laboratories, and private companies. 
Navy-funded research has produced many peer-reviewed articles in 
professional journals. This ongoing marine mammal research relates to 
hearing and hearing sensitivity, auditory effects, dive and behavioral 
response models, noise impacts, beaked whale global distribution, 
modeling of beaked whale hearing and response, tagging of free-ranging 
marine animals at-sea, and radar-based detection of marine mammals from 
ships. The Navy sponsors 70 percent of all U.S. research on the effects 
of human-generated underwater sound on marine mammals and 50 percent of 
such research conducted worldwide. These research projects may not be 
specifically related to SURTASS LFA sonar operations; however, they are 
crucial to the overall knowledge base on marine mammals and the 
potential effects from underwater anthropogenic noise. The Navy also 
sponsors research to determine marine mammal abundances and densities 
for all Navy ranges and other operational areas. The Navy notes that 
research and evaluation is being carried out on various monitoring and 
mitigation methods, including passive acoustic monitoring and the 
results from this research could be applicable to SURTASS LFA sonar 
passive acoustic monitoring. The Navy has also sponsored several 
workshops to evaluate the current state of knowledge and potential for 
future acoustic monitoring of marine mammals. The workshops bring 
together underwater acoustic subject matter experts and marine 
biologists from the Navy and

[[Page 880]]

other research organizations to present data and information on current 
acoustic monitoring research efforts, and to evaluate the potential for 
incorporating similar technology and methods on Navy instrumented 
ranges.

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 Sec.  216.104(a)(13) indicate that requests for 
LOAs must include the suggested means of accomplishing the necessary 
monitoring and reporting that will result in increased knowledge of the 
species, the level of taking, or impacts on populations of marine 
mammals that are expected to be present.
    Monitoring measures prescribed by NMFS should accomplish one or 
more of the following general goals:
    (a) An increase in our understanding of how many marine mammals are 
likely to be exposed to levels of LFA sonar that we associate with 
specific adverse effects, such as behavioral harassment, TTS, or PTS.
    (b) An increase in our understanding of how individual marine 
mammals respond (behaviorally or physiologically) to LFA sonar (at 
specific received levels or other stimuli expected to result in take.
    (c) An increase in our understanding of how anticipated takes of 
individuals (in different ways and to varying degrees) may impact the 
population, species, or stock (specifically through effects on annual 
rates of recruitment or survival).
    (d) An increase in knowledge of the affected species.
    (e) An increase in our understanding of the effectiveness of 
certain mitigation and monitoring measures.
    (f) A better understanding and record of the manner in which the 
authorized entity complies with the incidental take authorization.
    (g) An increase in the probability of detecting marine mammals, 
both within the mitigation zone (thus allowing for more effective 
implementation of the mitigation) and in general to better achieve the 
above goals.

Marine Mammal Monitoring (M3) Program

    The Marine Mammal Monitoring (M3) Program uses the Navy's permanent 
seafloor sensor arrays in areas of the Atlantic Ocean to passively 
monitor the movements of some large cetaceans, including their 
migration and feeding patterns, by tracking them through their 
vocalizations. Analysts can not only count numbers of whales, but in 
some cases also note the interaction and influence of underwater noise 
sources on the animals. Some whales are vocal enough to allow long-term 
tracking; e.g., in 2010 a blue whale was tracked for 67 days. Recently, 
upgraded acoustic signal processing systems have allowed for detection 
of sperm whale clicks--longest holding to date of one sperm whale is 12 
hrs, which included 14 dives. As previously noted these data are not 
real time and thus cannot be relied upon for mitigation purposes. At 
present, most of the data resulting from the M3 Program are classified. 
The Navy will continue to assess the data collected by its undersea 
arrays and work toward making some portion of that data, after 
appropriate security reviews, available to scientists with appropriate 
clearances. Any portions of the analyses conducted by these scientists 
based on these data that are determined to be unclassified after 
appropriate security reviews will be made publically available.

Passive Acoustic Monitoring With Fleet Exercises

    For fleet exercises that SURTASS LFA sonar is involved in, the Navy 
is exploring the feasibility of coordinating with other fleet assets 
and/or range monitoring programs to include the use of SURTASS towed 
horizontal line arrays to augment the collection of marine mammal 
vocalizations before, during, and after designated exercises. The goal 
would be to determine the extent, if any, of changes in marine mammal 
vocalizations that could have been caused by SURTASS LFA sonar 
operations during the exercise. This applies directly to increased 
knowledge of marine mammal species. If the collection of such 
calibrated and validated data can occur, this could be useful 
information in NMFS' environmental compliance processes for underwater 
LF sonar systems.
    This effort would require detailed pre-planning and a comprehensive 
data collection and analysis plan, which will necessarily be subject to 
the fleet operations plan for the exercise itself. Other factors that 
would need to be addressed include the following: Scheduling of assets; 
budgetary constraints; potential for qualified, professional marine 
mammal biologists to ride the SURTASS LFA sonar vessel during the data 
collection efforts; security measures; de-conflicting any potential 
behavioral responses of marine mammals in the fleet exercise area from 
other underwater sound sources (e.g., MF active sonars) with potential 
behavioral responses from SURTASS LFA sonar transmissions; and 
accounting for other variables that may cause a change in marine 
mammals' vocalization output. This would be a task for a scientific 
team made up of marine biologists, LFA operators, and meteorological/
oceanographic experts.

Ambient Noise Data Monitoring

    Several efforts (federal and academic) are underway to develop a 
comprehensive ocean noise budget (i.e., an accounting of the relative 
contributions of various underwater sources to the ocean noise field) 
for the world's oceans that include both anthropogenic and natural 
sources of noise. Ocean noise distributions and noise budgets are used 
in marine mammal masking studies, habitat characterization, and marine 
animal impact analyses.
    The Navy will collect ambient noise data when the SURTASS passive 
towed horizontal line array is deployed. The Navy is exploring the 
feasibility of declassifying and archiving the ambient noise data for 
incorporation into appropriate ocean noise budget efforts. Thus, the 
SURTASS LFA sonar vessels could serve as ad hoc ships of opportunity 
for monitoring data that could provide validation of marine mammal-
relevant global ocean noise budgets by supplying up-to-date 
measurements of the underwater noise field in data-poor and/or littoral 
areas not previously surveyed.

Past Monitoring

    The Navy's Low Frequency Sound Scientific Research Program (LFS 
SRP) in 1997 to 1998 provided insights to baleen whale responses to LFA 
sonar signals. The Navy designed the three-year study to assess the 
potential impacts of SURTASS LFA sonar on the behavior of low-frequency 
hearing specialists specifically addressing three important behavioral 
contexts for baleen whales: Feeding, migration, and breeding. The 
results of the LFS SRP confirmed that some portion of the total number 
of whales exposed to LFA sonar responded behaviorally by changing their 
vocal activity, moving away from the source vessel, or both; but the 
responses were short-lived (Clark et al., 2001) (see Potential Effects 
of Behavioral Disturbance).

Adaptive Management

    Our understanding of the potential effects of SURTASS LFA sonar on 
marine mammals is continually evolving. Reflecting this, the Navy 
proposes to include an adaptive

[[Page 881]]

management component within the framework of the scientific 
underpinning of its 2011 SEIS/OEIS that supports its application. This 
allows the Navy, in concert with NMFS, to consider, on a case-by-case 
basis, new/revised peer-reviewed and published scientific data and 
information from qualified and recognized sources within academia, 
industry, and government/non-government organizations to determine 
(with input regarding practicability) whether SURTASS LFA sonar 
mitigation, monitoring, or reporting measures should be modified 
(including additions or deletions); if new scientific data indicate 
that such modifications would be appropriate. It also allows for 
updates to marine mammal stock estimates to be included in annual LOA 
applications, which, in turn, provides for the use of the best 
available scientific data for predictive models, including AIM.

Proposed Reporting

    In order to issue an ITA for an activity, section 101(a)(5)(A) of 
the MMPA states that NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking''. Effective reporting is 
critical both to compliance as well as ensuring that the most value is 
obtained from the required monitoring. There are several different 
reporting requirements in these proposed regulations:

General Notification of Injured or Dead Marine Mammals

    The Navy will systematically observe SURTASS LFA sonar operations 
for injured or disabled marine mammals. In addition, the Navy will 
monitor the principal marine mammal stranding networks and other media 
to correlate analysis of any whale strandings that could potentially be 
associated with SURTASS LFA sonar operations.
    Navy personnel will ensure that NMFS is notified immediately or as 
soon as clearance procedures allow if an injured, stranded, or dead 
marine mammal is found during or shortly after, and in the vicinity of, 
any SURTASS LFA operations. The Navy will provide NMFS with species or 
description of the animal(s), the condition of the animal(s) (including 
carcass condition if the animal is dead), location, time of first 
discovery, observed behaviors (if alive), and photo or video (if 
available).
    In the event that an injured, stranded, or dead marine mammal is 
found by the Navy that is not in the vicinity of, or found during or 
shortly after SURTASS LFA sonar operations, the Navy will report the 
same information as listed above as soon as operationally feasible and 
clearance procedures allow.

General Notification of a Ship Strike

    Because SURTASS LFA vessels move slowly, it is not likely these 
vessels would strike a marine mammal. In the event of a ship strike by 
the SURTASS LFA vessel, at any time or place, the Navy shall do the 
following:
     Immediately report to NMFS the species identification (if 
known), location (lat/long) of the animal (or the strike if the animal 
has disappeared), and whether the animal is alive or dead (or unknown);
     Report to NMFS as soon as operationally feasible the size 
and length of the animal, an estimate of the injury status (e.g., dead, 
injured but alive, injured and moving, unknown, etc.), vessel class/
type and operational status;
     Report to NMFS the vessel length, speed, and heading as 
soon as feasible; and
     Provide NMFS a photo or video, if equipment is available.

Long-Term Monitoring (LTM) Program Reports

    During routine operations of SURTASS LFA sonar, the Navy will 
collect and record technical and environmental data, which are part of 
the Navy's LTM Program. These would include data from visual and 
acoustic monitoring, ocean environmental measurements, and technical 
operational inputs.

Quarterly Mitigation Monitoring Report

    On a quarterly basis, the Navy would provide NMFS with classified 
and unclassified reports that include all active-mode missions 
completed 30 days or more prior to the date of the deadline for the 
report. Specifically, these reports will include dates/times of 
exercises, location of vessel, mission operational area, location of 
the mitigation zone in relation to the LFA sonar array, marine mammal 
observations, and records of any delays or suspensions of operations. 
Marine mammal observations would include animal type and/or species, 
number of animals sighted by species, date and time of observations, 
type of detection (visual, passive acoustic, HF/M3 sonar), the animal's 
bearing and range from vessel, behavior, and remarks/narrative (as 
necessary). The report would include the Navy's analysis of whether any 
Level A and/or Level B taking occurred within the SURTASS LFA sonar 
mitigation zone and, if so, estimates of the percentage of marine 
mammal stocks affected (both for the quarter and cumulatively (to date) 
for the year covered by the LOA) by SURTASS LFA sonar operations. This 
analysis would include estimates for both within and outside the LFA 
sonar mitigation zone, using predictive modeling based on operating 
locations, dates/times of operations, system characteristics, 
oceanographic environmental conditions, and animal demographics. In the 
event that no SURTASS LFA missions are completed during a quarter, the 
Navy will provide NMFS with a report of negative activity.

Annual Report

    The annual report, which is due no later than 45 days after the 
expiration date of the LOAs, would provide NMFS with an unclassified 
summary of the year's quarterly reports and will include the Navy's 
analysis of whether any Level A and/or Level B taking occurred within 
the SURTASS LFA sonar mitigation zones and, if so, estimates of the 
percentage of marine mammal stocks affected by SURTASS LFA sonar 
operations. This analysis would include estimates for both within and 
outside the LFA sonar mitigation zones, using predictive modeling based 
on operating locations, dates/times of operations, system 
characteristics, oceanographic environmental conditions, and animal 
demographics.
    The annual report would also include: (1) Analysis of the 
effectiveness of the mitigation measures with recommendations for 
improvements where applicable; (2) assessment of any long-term effects 
from SURTASS LFA sonar operations; and (3) any discernible or estimated 
cumulative impacts from SURTASS LFA sonar operations.

Comprehensive Report

    NMFS proposes to require the Navy to provide NMFS and the public 
with a final comprehensive report analyzing the impacts of SURTASS LFA 
sonar on marine mammal species and stocks. This report, which is due at 
least 240 days prior to expiration of these regulations, would include 
an in-depth analysis of all monitoring and Navy-funded research 
pertinent to SURTASS LFA sonar operations conducted during the 5-year 
period of these regulations, a scientific assessment of cumulative 
impacts on marine mammal stocks, and an analysis on the advancement of 
alternative (passive) technologies as a replacement for LFA sonar. This 
report would be a key document for NMFS' review and assessment of 
impacts for any future rulemaking.
    The Navy shall respond to NMFS comments and requests for additional

[[Page 882]]

information or clarification on quarterly, annual or comprehensive 
report. These reports will be considered final after the Navy has 
adequately addressed NMFS' comments or provided the requested 
information, or three months after the submittal of the draft if NMFS 
does not comment within the three-month time period. NMFS will post the 
annual and comprehensive reports on the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.

Estimated Take of Marine Mammals

    As mentioned previously, one of the main purposes of NMFS' effects 
assessments is to identify the permissible methods of taking, meaning: 
the nature of the take (e.g., resulting from anthropogenic noise vs. 
from ship strike, etc.); the regulatory level of take (i.e., mortality 
vs. Level A or Level B harassment) and the amount of take. The 
Potential Effects section identified the lethal responses, physical 
trauma, sensory impairment (permanent and temporary threshold shifts 
and acoustic masking), physiological responses (particular stress 
responses), and behavioral responses that could potentially result from 
exposure to SURTASS LFA sonar operations. This section will relate the 
potential effects to marine mammals from SURTASS LFA sonar operations 
to the MMPA statutory definitions of Level A and Level B Harassment and 
attempt to quantify the effects that might occur from the specific 
training activities that the Navy has proposed.
    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, though, 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, and other pertinent 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 
are sometimes contributing 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].

Level B Harassment

    Of the potential effects that were described in the previous 
sections, 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 SURTASS LFA sonar or HF/M3 sonar (or another stressor), is 
considered Level B Harassment. Louder sounds (when other factors are 
not considered) are generally expected to elicit a stronger response 
than softer sounds. Some of the lower level physiological stress 
responses discussed in the previous sections will 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.
    In the effects section above, we described the Southall et al. 
(2007) severity scaling system and listed some examples of the three 
broad categories of behaviors 0-3: (Minor and/or brief behaviors); 4-6: 
(Behaviors with higher potential to affect foraging, reproduction, or 
survival); 7-9: (Behaviors considered likely to affect the 
aforementioned vital rates). Generally speaking, MMPA Level B 
Harassment, as defined in this document, would include the behaviors 
described in the 7-9 category and a subset, dependent on context and 
other considerations, of the behaviors described in the 4-6 category. 
Behavioral harassment typically would not include behaviors ranked 0-3.
    Acoustic Masking and Communication Impairment--The severity or 
importance of an acoustic masking event can vary based on the length of 
time that the masking occurs, the frequency of the masking signal 
(which determines which sounds are masked, which may be of varying 
importance to the animal), and other factors. Some acoustic masking 
would be considered Level B Harassment, if it can disrupt natural 
behavioral patterns by interrupting or limiting the marine mammal's 
receipt or transmittal of important information or environmental cues.
    TTS--As discussed previously, TTS can disrupt behavioral patterns 
by inhibiting an animal's ability to communicate with conspecifics and 
interpret other environmental cues important for predator avoidance and 
prey capture. However, 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). For example, a marine mammal may be 
able to readily compensate for a brief, relatively small amount of TTS 
in a non-critical frequency range that takes place during a time when 
the animal is traveling through the open ocean, where ambient noise is 
lower and there are not as many competing sounds present. 
Alternatively, a larger amount and longer duration of TTS sustained 
during a time when communication is critical for successful mother/calf 
interactions could have more serious impacts if it was in the same 
frequency band as the necessary vocalizations and of a severity that 
impeded communication.
    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) indicates that although PTS is a 
tissue injury, TTS is not, because the reduced hearing sensitivity 
following exposure to intense sound results primarily from

[[Page 883]]

fatigue, not loss, of cochlear hair cells and supporting structures and 
is reversible. Accordingly, NMFS classifies TTS (when resulting from 
exposure to either SURTASS LFA sonar or HF/M3 sonar) as Level B 
Harassment, not Level A Harassment (injury).

Level A Harassment

    Of the potential effects that were described in the previous 
sections, the following are the types of effects that fall into the 
Level A Harassment category:
    PTS--PTS (resulting from either exposure to SURTASS LFA sonar or 
HF/M3 sonar) 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. Although 
PTS is considered an injury, the effects of PTS on the fitness of an 
individual can vary based on the degree of TTS and its frequency band.
    Tissue Damage due to Acoustically Mediated Bubble Growth--A few 
theories suggest ways in which gas bubbles become enlarged through 
exposure to intense sounds (SURTASS LFA sonar or HF/M3 sonar) to the 
point where tissue damage results. In rectified diffusion, exposure to 
a sound field would cause bubbles to increase in size. A short duration 
of active sonar pings (such as that which an animal exposed to SURTASS 
LFA sonar) 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. Still, possible tissue damage from either of these 
processes would be considered an injury or, potentially, mortality.
    Tissue Damage due to Behaviorally Mediated Bubble Growth--Several 
authors suggest mechanisms in which marine mammals could behaviorally 
respond to exposure to SURTASS LFA sonar or HF/M3 sonar by altering 
their dive patterns in a manner (unusually rapid ascent, unusually long 
series of surface dives, etc.) that might result in unusual bubble 
formation or growth ultimately resulting in tissue damage (e.g., 
emboli). 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 the tissue effects observed from recent beaked 
whale strandings are consistent with gas emboli and bubble-induced 
tissue separations (Jepson et al., 2003; Fernandez et al., 2005; Tyack 
et al., 2006), 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 or, potentially, mortality.

Estimates of Potential Marine Mammal Exposure

    Estimating the take that will result from the proposed activities 
begins with the CNO and fleet commands proposing mission areas to 
operate SURTASS LFA sonar. The Navy analyzes the mission areas based on 
current scientific data to determine the potential sensitivity of 
marine mammals to SURTASS LFA sonar signals and risks to their stocks. 
If marine mammal densities prove to be high and/or sensitive animal 
activities are expected, the Navy changes/refines the mission areas to 
areas with lower numbers of marine mammals, or lower levels of 
biologically-sensitive marine mammal activities. Subsequently the 
process is re-initiated for the modified mission area. Next, the Navy 
performs standard acoustic modeling and risk analyses, taking into 
account spatial, temporal, and/or operational restrictions. Then, the 
Navy applies standard mitigation measures to the analysis to calculate 
risk estimates for marine mammal stocks in the proposed mission area. 
Based on these estimates, the Navy decides if the proposed mission area 
meets the conditions of the MMPA regulations and LOAs, as issued, on 
marine mammal/animal impacts from SURTASS LFA sonar. If not, the 
proposed mission area is changed or refined, and the process is re-
initiated. If the mission area risk estimates are below the required 
restrictions, then the Navy has identified and selected the potential 
mission area with minimal marine mammal/animal activity consistent with 
its operational readiness requirements and restrictions placed on LFA 
operations by NMFS in the regulatory and consultation processes. This 
sensitivity/risk assessment approach allows the Navy to determine where 
and when SURTASS LFA sonar can operate and meet the MMPA condition for 
the least practicable adverse impacts on marine mammals.
    As described earlier (see Brief Background on the Navy's Assessment 
of the Potential Impacts on Marine Mammals), the Navy assesses the 
potential impacts on marine mammals predicting the sound field that a 
given marine mammal species could be exposed to over time in a 
potential operating area. This is a multi-part process involving: (1) 
The ability to measure or estimate an animal's location in space and 
time; (2) the ability to measure or estimate the three-dimensional 
sound field at these times and locations; (3) the integration of these 
two data sets into the AIM to estimate the total acoustic exposure for 
each animal in the modeled population; (4) the conversion of the 
resultant cumulative exposures for a modeled population into an 
estimate of the risk from a significant disturbance of a biologically 
important behavior; and (5) the use of a risk continuum to convert 
these estimates of behavioral risk into an assessment of risk in terms 
of the level of potential biological removal.
    The Navy uses the LFA sonar mitigation zone to calculate estimates 
for Level A harassment (injury). The area between the LFA sonar 
mitigation zone and the 1-km (0.62 mi; 0.54 nmi) buffer zone (estimated 
to extend to about the 174-dB isopleth) is an area where marine mammals 
could experience Level B harassment. The Navy uses this area to 
calculate estimates for Level B harassment using a risk continuum from 
the 120 to 179-dB isopleth for marine mammals. Based on the Navy's AIM 
modeling results, the primary effects would be the potential for Level 
B Harassment. In addition, while possible, Level A harassment, if it 
occurs at all, is expected to be so minimal as to have no effect on 
rates of reproduction or survival of affected marine mammal species. 
More information regarding the risk assessment methodology, the models 
used, the assumptions used in the models, and the process of estimating 
take is available in section 6.4 of the Navy's application and section 
4.4 of the Navy's 2007 Final SEIS and section 4.4 of the Navy's DSEIS/
SOEIS.
    Because it is infeasible to model enough representative sites to 
cover all potential LFA operating areas, the Navy's application 
presents 19 modeled sites as examples to provide estimates of potential 
operating areas based on the current political climate. The Navy

[[Page 884]]

analyzed these 19 operating sites using the most up-to-date marine 
mammal abundance, density, and behavioral information available. These 
sites they represent, based on today's political climate, areas where 
SURTASS LFA sonar could potentially test, train, or operate. Tables 9 
through 27 provide the Navy's estimates of the number of marine mammals 
potentially affected for SURTASS LFA sonar operations and are based on 
reasonable and realistic estimates of the potential effects to marine 
mammal stocks specific to the potential mission areas. These data are 
examples of areas where the Navy could request LOAs under the 5-year 
rule because they are in areas of potential strategic importance and/or 
areas of possible naval fleet exercises. As stated previously, this 
proposed rule does not specify the number of marine mammals that may be 
taken in the proposed locations because these are determined annually 
through various inputs such as mission location, mission duration, and 
season of operation. For the annual application for an LOA, the Navy 
proposes to present both the estimated percentage of stock incidentally 
harassed as well as the estimated number of animals that may be 
potentially harassed by SURTASS LFA sonar.
    With the implementation of the three-part monitoring programs 
(visual, passive acoustic, and HF/M3 monitoring), NMFS and the Navy do 
not expect that marine mammals would be injured by SURTASS LFA sonar 
because a marine mammal should be detected and active transmissions 
suspended or delayed. As mentioned previously, the Navy determines 
Level A harassments based on actual observations and/or detections 
within the LFA sonar mitigation zone. The probability of detection of a 
marine mammal by the HF/M3 system within the LFA sonar mitigation zone 
approaches 100 percent based on multiple pings (see the 2001 FOEIS/EIS, 
Subchapters 2.3.2.2 and 4.2.7.1 for the HF/M3 sonar testing results). 
In the Navy's application, the Navy's acoustic analyses predict that 
less than 0.0001 percent of the endangered north Pacific right whale 
stock and 0.00 percent of the stocks of all other marine mammal species 
may be exposed to levels of sound likely to result in Level A 
harassment (i.e., exposures at 180 dB re: 1 [micro]Pa or greater). 
Quantitatively, the Navy's request translates into take estimates of 
zero animals for any species including the endangered north Pacific 
right whale. However, because the probability of detection by the HF/M3 
system within the LFA sonar mitigation zone is not 100 percent, NMFS 
will include a small number of Level A harassment takes for marine 
mammals over the course of the five-year regulations based on 
qualitative analyses.
    Reviewing the Navy's historical data on visual alerts that have 
triggered a suspension of SURTASS LFA sonar transmission outside of the 
LFA sonar mitigation zone, the data indicate that the largest grouping 
of mysticetes that has triggered a shutdown outside of the LFA sonar 
mitigation zone and within the buffer zone is three. Similarly, the 
largest number of odontocetes that has triggered a shutdown is two. 
Thus, NMFS analyzes the take of no more than six mysticetes (total), 
across all species requested in the Navy's application by Level A 
harassment; no more than 25 odontocetes (across all species) by Level A 
harassment; and no more than 25 pinnipeds (across all species) by Level 
A harassment over the course of the 5-year regulations. These are the 
only quantitative adjustments that NMFS has made to the requested takes 
from the Navy's modeled exposure results. Again, NMFS notes that over 
the course of the previous two rulemakings, there have been no reported 
incidents of Level A harassment of any marine mammal. As with the 2002 
and 2007 Rules, the Navy will limit operation of LFA sonar to ensure no 
marine mammal stock will be subject to more that 12 percent of takes by 
Level B harassment annually, over the course of the five-year 
regulations. This annual per-stock cap applies regardless of the number 
of LFA vessels operating. The Navy will use the 12 percent cap to guide 
its mission planning and annual LOA applications.

Analysis and Negligible Impact Preliminary Determination

    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.'' In making a negligible impact determination, 
NMFS considers:
    (1) The number of anticipated mortalities;
    (2) The number and nature of anticipated injuries;
    (3) The number, nature, and intensity, and duration of Level B 
harassment; and
    (4) The context in which the takes occur.
    As mentioned previously, NMFS estimates that 94 species of marine 
mammals could be potentially affected by Level A or Level B harassment 
over the course of the five-year period.
    For reasons stated previously in this document, no mortalities are 
anticipated to occur as a result of the Navy's proposed SURTASS LFA 
operations, and none are proposed to be authorized by NMFS.
    Pursuant to NMFS' regulations implementing the MMPA, an applicant 
is required to estimate the number of animals that will be ``taken'' by 
the specified activities and the type of taking (i.e., takes by 
harassment only, or takes by harassment, injury, and/or death). This 
estimate informs the analysis that NMFS must perform to determine 
whether the activity will have a ``negligible impact'' on the affected 
species or stock. Level B (behavioral) harassment occurs at the level 
of the individual(s) and does not assume any resulting population-level 
consequences (see Potential Effects of Behavioral Disturbance).
    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 Level B harassment takes, 
alone, is not enough information on which to base an impact 
determination. As mentioned previously, in addition to considering 
estimates of the number of marine mammals that might be ``taken'' 
through behavioral harassment, 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 of 
estimated Level A harassment takes, the number of estimated 
mortalities, and effects on habitat. 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 Navy has described its specified activities based on best 
estimates of the number of hours that the Navy will conduct SURTASS LFA 
operations. The exact number of transmission hours may vary from year 
to year, but will not exceed the annual total indicated in Table 1.
    Taking the above into account, considering the sections discussed 
further, and dependent upon the implementation of the proposed 
mitigation measures, NMFS has preliminarily determined that Navy

[[Page 885]]

training, testing, and military operations utilizing SURTASS LFA sonar 
will have a negligible impact on the marine mammal species and stocks 
present in operational areas in certain areas of the Pacific, Atlantic, 
and Indian Oceans and the Mediterranean Sea.

Behavioral Harassment

    As discussed in the Potential Effects of Exposure to SURTASS LFA 
Sonar Operations, marine mammals may respond to SURTASS LFA sonar 
operations in many different ways, a subset of which qualifies as 
harassment (see Behavioral Harassment Section). One thing that the take 
estimates do not take into account is the fact that most marine mammals 
will likely avoid strong sound sources to one extent or another. 
Although an animal that avoids the sound source will still be taken in 
some instances (such as if the avoidance results in a missed 
opportunity to feed, interruption of reproductive behaviors, etc.) in 
other cases avoidance may result in fewer instances of take than were 
estimated or in the takes resulting from exposure to a lower received 
level than was estimated, which could result in a less severe response.
    For SURTASS LFA sonar operations, the Navy provided information 
(Tables 24-42 of the Navy's application) estimating numbers of total 
takes that could occur within the proposed operational areas. For 
reasons stated previously in this document, the specified activities 
associated with the proposed SURTASS LFA operations will most likely 
fall within the realm of short-term, Level B behavioral harassment. 
NMFS bases this assessment on a number of factors:
    (1) Geographic Restrictions--With the implementation of geographic 
restrictions on SURTASS LFA sonar operations, NMFS and the Navy have 
minimized the likelihood of disruption of marine mammal behavior 
patterns, such as migration, calving, breeding, feeding, or sheltering. 
Because the coastal standoff and proposed OBIAs restrict the use of 
SURTASS LFA sonar in known areas of feeding, calving, and breeding for 
marine mammals, NMFS does not expect nor does it anticipate that 
SURTASS LFA sonar operations likely will have adverse effects on annual 
rates of recruitment or survival (i.e., population-level effects).
    Also, the Navy's proposal to not conduct SURTASS LFA sonar 
operations within 22 km (13. mi; 11.8 nmi) of any coastline, including 
islands, to ensure that the sound field does not exceed 180 dB (i.e., 
LFA mitigation and buffer zones) offers protection to areas with higher 
densities of marine mammals. Because the Navy will operate for the most 
part in waters that are not areas known for high concentrations of 
marine mammals, few, if any, marine mammals would be within the SURTASS 
LFA mitigation and buffer zones.
    (2) Low Frequency Sonar Scientific Research Program (LFS SRP)--
Based on the past nine years of SURTASS LFA sonar operations and the 
LFS SRP, NMFS does not expect nor does it anticipate that SURTASS LFA 
sonar operations will have likely adverse effects on annual rates of 
recruitment or survival (i.e., population-level effects). The Navy 
designed the three-year study to assess the potential impacts of 
SURTASS LFA sonar on the behavior of low-frequency hearing specialists, 
those species believed to be at (potentially) greatest risk. This field 
research addressed three important behavioral contexts for baleen 
whales: (1) Blue and fin whales feeding in the southern California 
Bight, (2) gray whales migrating past the central California coast, and 
(3) humpback whales breeding off Hawaii. Taken together, the results 
from the three phases of the LFS SRP do not support the hypothesis that 
most baleen whales exposed to RLs near 140 dB re: 1 [mu]Pa would 
exhibit disturbance behavior and avoid the area. These experiments, 
which exposed baleen whales to received levels ranging from 120 to 
about 155 dB re: 1 [mu]Pa, detected only minor, short-term behavioral 
responses. However, short-term behavioral responses do not necessarily 
constitute significant changes in biologically important behaviors.
    (3) Efficacy of the Navy's Three-Part Mitigation Monitoring 
Program--From 2003 to 2010, the Navy reported a total of 12 visual 
sightings, four passive acoustic detections, and 130 HF/M3 active sonar 
detections of marine mammals, all leading to suspension/delays of 
transmissions in accordance with mitigation protocols. Because the HF/
M3 active sonar is able to monitor large and medium marine mammals out 
to an effective range of 2 to 2.5 km (1.2 to 1.5 mi; 1.1 to 1.3 nmi) 
from the vessel, it is unlikely that the SURTASS LFA operations would 
expose marine mammals to an SPL greater than about 174 dB re: 1 [mu]Pa 
at 1 m. The area between the 180-dB LFA sonar mitigation zone and the 
1-km (0.62 mi; 0.54 nm) buffer zone proposed by NMFS (estimated to 
extend to about the 174-dB isopleth from the vessel) is an area where 
marine mammals would experience Level B Harassment if exposed to LFA 
sonar transmissions, in accordance with the Navy's risk analysis and 
acoustic modeling (2001 FOEIS/EIS, Subchapter 4.2.3). Past results of 
the HF/M3 sonar system tests provide confirmation that the system has a 
demonstrated probability of single-ping detection of 95 percent or 
greater for single marine mammals, 10 m (32.8 ft) in length or larger, 
and a probability approaching 100 percent for multiple pings for any 
sized marine mammal. Further, implementing a shutdown zone of 
approximately 2 km (1.2 mi; 1.1 nmi) around the vessel will ensure that 
no marine mammals are exposed to an SPL greater than about 174 dB re: 1 
[mu]Pa at 1 m.

TTS

    Schlundt et al. (2000) documented TTS in trained bottlenose 
dolphins and belugas after exposure to intense 1-second signal duration 
tones at 400 Hz, and 3, 10, 20, and 75 Hz. NMFS notes the LF-band tones 
at 400 Hz at which the researchers were unable to induce TTS in any 
animal at levels up to 193 dB re: 1 [mu]Pa at 1 m which was the maximum 
level achievable with the equipment used in the experiment. The 
researchers implied that the TTS threshold for a 100-second signal 
would be approximately 184 dB (Table 1-4, 2001 FOEIS/EIS).
    When SURTASS LFA sonar transmits, there is a boundary that encloses 
a volume of water where received levels equal or exceed 180 dB (the 
180-dB isopleth LFA sonar mitigation zone) and a volume of water 
outside this boundary where received levels are below 180 dB (the 1 km 
buffer encircling the 180-dB LFA sonar mitigation zone. The level of 
risk for TTS for marine mammals depends on their location in relation 
to SURTASS LFA sonar. Because the onset of PTS for marine mammals may 
be 15-20 dB above TTS levels, one can assume that a marine mammal would 
have to be within the 1 km buffer around the 180-dB LFA sonar 
mitigation zone (i.e., modeled SPLs of 120-180 dB re: 1 [mu]Pa at 1 m) 
to induce TTS. However, the Navy's standard protective measures 
indicate that they would ensure delay or suspension of SURTASS LFA 
sonar transmissions if any of the three monitoring programs detect a 
marine mammal within 2 km (1.2 mi; 1.1 nmi) of the vessel. Thus, the 
proposed mitigation measures would allow the Navy to reduce the number 
of marine mammals exposed to received levels of SURTASS LFA sonar or 
HF/M3 sonar sound that could result in TTS. For transient sounds, the 
sound level necessary to cause TTS is inversely related to the duration 
of the sound. Again, in the case of SURTASS LFA, animals are not 
expected to be exposed

[[Page 886]]

to levels high enough or durations long enough to result in TTS. In 
order to receive more than one ``ping'' during a normal vessel leg, an 
animal would need to match the ship in speed and course direction 
between pings. Because of the relatively short duty cycle, the water 
depth of the convergence zone ray path, the movement of marine mammals 
in relationship to the SURTASS LFA sonar ship, and the effectiveness of 
the three-part mitigation program, few marine mammals are likely to be 
affected by TTS (see Direct Physiological Effects--Threshold Shift 
(Noise-Induced Loss of Hearing).

PTS

    In NMFS' 2002 and 2007 rules, NMFS and the Navy based their 
estimate of take by injury or the significant potential for such take 
(Level A harassment) on the criterion of 180 dB. NMFS continues to 
believe this is a scientifically supportable and conservative value for 
preventing auditory injury or the significant potential for such injury 
(Level A harassment), as it represents a value less than where the 
potential onset of a minor TTS in hearing might occur based on Schlundt 
et al.'s (2000) research (see the Navy's 2007 Final Comprehensive 
Report Tables 5 through 8).
    The Navy's standard protective measures indicate that they would 
ensure delay or suspension of SURTASS LFA sonar transmissions if any of 
the three monitoring programs detect a marine mammal either entering 
the LFA sonar mitigation zone or buffer zones; (within approximately 
two km (1.2 mi; 1.1 nmi)) of the LFA transmit array or vessel. The 
proposed mitigation measures would allow the Navy to avoid exposing 
marine mammals to received levels of SURTASS LFA sonar or HF/M3 sonar 
sound that would result in injury (Level A harassment). The sound 
pressure level (SPL) that is capable of potentially causing injury to 
an animal is within approximately 1 km (0.62 mi; 0.54 nm) of the ship. 
Implementing a shutdown zone of approximately 2 km (1.2 mi; 1.1 nmi) 
around the LFA sonar array and vessel will ensure that no marine 
mammals are exposed to an SPL greater than about 174 dB re: 1 [mu]Pa 
(RL). This is significantly lower than the 180-dB re: 1 [mu]Pa (RL) 
used for other acoustic projects for protecting marine mammals from 
injury. Serious injury is unlikely to occur unless a marine mammal is 
well within the 180-dB LFA sonar mitigation zone and close to the 
source. The closer the mammal is to the vessel, the more likely it will 
be detected by the tripartite monitoring program leading to the 
immediate suspension of SURTASS LFA sonar transmissions.
    With three levels of mitigation monitoring for detecting marine 
mammals, NMFS believes it is unlikely that any marine mammal would be 
exposed to received levels of 180 dB re: 1 [mu]Pa before being detected 
and the SURTASS LFA sonar shut down. However, because the probability 
is not zero, the Navy has requested Level A harassment takes incidental 
to SURTASS LFA sonar operations.

Mortality

    There is no empirical evidence of strandings of marine mammals 
associated with the employment of SURTASS LFA sonar. Moreover, the 
system acoustic characteristics differ between LF and MF sonars 
associated with strandings: LFA sonars use frequencies generally below 
1,000 Hz, with relatively long signals (pulses) on the order of 60 sec; 
while MF sonars use frequencies greater than 1,000 Hz, with relatively 
short signals on the order of 1 sec. NMFS has provided a summary of 
common features shared by the strandings events in Greece (1996), 
Bahamas (2000), Madeira (2000), Canary Islands (2002), Hanalei Bay 
(2004), and Spain (2006) earlier in this document. These included 
operation of MF sonar, deep water close to land (such as offshore 
canyons), presence of an acoustic waveguide (surface duct conditions), 
and periodic sequences of transient pulses (i.e., rapid onset and decay 
times) generated at depths less than 32.8 ft (10 m) by sound sources 
moving at speeds of 2.6 m/s (5.1 knots) or more during sonar operations 
(D'Spain et al., 2006). None of these features relate to SURTASS LFA 
sonar operations.
    In summary (from the discussion above this section), NMFS has made 
a preliminary finding that the total taking from SURTASS LFA activities 
will have a negligible impact on the affected species or stocks based 
on following: (1) The historical effectiveness of the Navy's three-part 
monitoring program in detecting marine mammals and triggering 
shutdowns, which make it unlikely that an animal will be exposed to 
sound levels above 180 dB (i.e., levels potentially associated with 
injury); (2) Geographic restrictions such as OBIAs and the coastal 
standoff zone; (3) The requirement that the SURTASS LFA sonar sound 
field not exceed 180 dB within 22 km of any shoreline, including 
islands, or at a distance of one km from the perimeter of an OBIA; (4) 
The fact that LF signals attenuate greatly in the near-surface zone, 
where many of the marine mammals congregate for biologically-important 
behaviors; (5) The small number of SURTASS LFA sonar systems that would 
be operating world-wide; (6) The relatively low duty cycle, short 
mission periods and offshore nature of the SURTASS LFA sonar; (7) The 
fact that marine mammals in unspecified migration corridors and open 
ocean concentrations would be adequately protected by the three-part 
monitoring and mitigation protocols; and (8) Previous Endangered 
Species Act consultation findings that that operation of the SURTASS 
LFA sonar is not likely to jeopardize the continued existence of any 
endangered or threatened species under the jurisdiction of NMFS or 
result in the destruction or adverse modification of critical habitat. 
Impacts to marine mammals are anticipated to be in the form of Level B 
behavioral harassment, due to the brief duration and sporadic nature of 
the SURTASS LFA sonar operations. Certain species may have a behavioral 
reaction (e.g., increased swim speed, avoidance of the area, etc.) to 
the sound emitted during the proposed activities. In conclusion, while 
marine mammals will potentially be affected by the SURTASS LFA sonar 
sounds, NMFS has preliminarily determined that these impacts will be 
short-term and are not reasonably likely to adversely affect the 
species or stock through effects on annual rates of recruitment or 
survival.

Subsistence Harvest of Marine Mammals

    Although the Navy will not operate SURTASS LFA sonar in the vast 
majority of Arctic waters, the Navy may potentially operate LFA sonar 
in the Gulf of Alaska, where subsistence uses of marine mammals occur. 
Subsistence uses of marine mammals in the Gulf of Alaska include the 
harvest of harbor seals and Steller sea lions along coastal and 
inshore, including bay, areas of the gulf. As many as six Alaskan 
Native groups subsistence hunt harbor seals in the Gulf of Alaska, 
although the Dena'ina only occasionally hunt harbor seals, and four 
Native groups hunt Steller sea lions, with the Southeastern Alaska 
Native groups only occasionally harvesting Stellers (Wolfe et al., 
2009). Subsistence products that are derived from harbor seals and 
Steller sea lions by these Alaskan Native groups include oil, meat, and 
skins. Subsistence hunting of harbor seals and Steller sea lions is a 
specialized activity among Alaska Native groups, with only 30 percent 
and 3 percent of the surveyed native households hunting harbor seals 
and Steller sea lions, respectively (Wolfe et al., 2009).

[[Page 887]]

    Should the Navy operate SURTASS LFA sonar in the Gulf of Alaska, 
sonar operation would adhere to the shutdown in the mitigation and 
buffer zones, we well as established geographic restrictions, which 
include the coastal standoff range (which dictates that the sound field 
produced by the sonar must be below 180 dB re: 1 [mu]Pa at 1 m within 
22 km (13. mi; 11.8 nmi) of any coastline) and exclusion from OBIAs.
    Although there are peaks in harvest activity for both species, both 
harbor seals and Steller sea lions are harvested year-round in the 
coastal waters of the gulf. While it is impossible to predict the 
future timing of the possible employment of SURTASS LFA sonar in the 
Gulf of Alaska, regardless of the time of year the sonar may be 
employed in the Gulf of Alaska, there should be no overlap in time or 
space with subsistence hunts due to the geographic restrictions on the 
sonar use (i.e., coastal standoff range and OBIA restrictions). These 
restrictions will prevent the Navy from generating a sound field that 
reaches the shallow coastal and inshore areas of the Gulf of Alaska 
where harvest of the two pinniped species occurs. The possible 
employment of SURTASS LFA sonar in the Gulf of Alaska will not cause 
abandonment of any harvest/hunting locations, will not displace any 
subsistence users, nor place physical barriers between marine mammals 
and the hunters. No mortalities of marine mammals have been associated 
with the employment of SURTASS LFA sonar and the Navy undertakes a 
suite of mitigation measures whenever SURTASS LFA sonar is actively 
transmitting. Therefore, NMFS has preliminarily determined that the 
possible future employment of SURTASS LFA sonar will not lead to 
unmitigable adverse impacts on the availability of marine mammal 
species or stocks for subsistence uses in the Gulf of Alaska.
    In August 2011, the Navy sent a letter to the Native Affairs and 
Natural Resources Advisor, Alaska Command at Elmendorf Air Force base 
requesting that they provide copies of the SURTASS LFA Sonar DSEIS/
SOEIS (DoN, 2011) to pertinent native groups that participate in 
subsistence hunting in the Gulf of Alaska. To date, the Navy has not 
received any requests from Alaskan tribes for government-to-government 
consultation pursuant to Executive Order 13175. The Navy will continue 
to keep the Alaskan tribes informed of the timeframes of any future 
SURTASS LFA sonar exercises planned for the area.

Endangered Species Act

    There are 15 marine mammal species under NMFS' jurisdiction that 
are listed as endangered or threatened under the ESA with confirmed or 
possible occurrence in potential operational areas for SURTASS LFA: the 
blue, fin, sei humpback, bowhead, North Atlantic right, North Pacific 
right, southern right, gray, and sperm whales, as well as the western 
and eastern distinct population segments (DPS) of the Steller sea lion, 
Mediterranean monk seal, Hawaiian monk seal, the eastern DPS of the 
Steller sea lion; the Guadalupe fur seal and the southern DPS of the 
spotted seal.
    On October 4, 1999, the Navy submitted a Biological Assessment to 
NMFS to initiate consultation under section 7 of the ESA for its 
SURTASS LFA sonar activities. NMFS concluded consultation with the Navy 
on this action on May 30, 2002. The conclusion of that consultation was 
that operation of the SURTASS LFA sonar system for testing, training 
and military operations and the issuance by NMFS of incidental take 
authorizations for this activity are not likely to jeopardize the 
continued existence of any endangered or threatened species under the 
jurisdiction of NMFS. The Navy and NMFS conducted additional 
consultations prior to issuance of the annual LOAs.
    On June 9, 2006, the Navy submitted a Biological Assessment to NMFS 
to initiate consultation under section 7 of the ESA for the 2007-2012 
SURTASS LFA sonar activities and NMFS' authorization for incidental 
take under the MMPA. NMFS concluded consultation with the Navy on this 
action on August 17, 2007. The conclusion of that consultation was that 
operation of the SURTASS LFA sonar system for testing, training and 
military operations and the issuance by NMFS of MMPA incidental take 
authorizations for this activity are not likely to jeopardize the 
continued existence of any endangered or threatened species under the 
jurisdiction of NMFS or result in the destruction or adverse 
modification of critical habitat. As with the first rule, the Navy and 
NMFS conducted additional consultations prior to issuance of the annual 
LOAs.
    The Navy will consult with NMFS pursuant to section 7 of the ESA, 
and NMFS will also consult internally on the issuance of regulations 
and LOAs under section 101(a)(5)(A) of the MMPA for SURTASS LFA sonar 
activities. NMFS will conclude consultation with itself and the Navy 
prior to making a determination on the issuance of the final rule and 
LOAs.
    The USFWS is responsible for regulating the take of the several 
marine mammal species including the southern sea otter, polar bear, 
walrus, West African manatee, Amazonian manatee, West Indian manatee, 
and dugong. None of these species occur in geographic areas that 
overlap with SURTASS LFA sonar operations. Therefore, the Navy has 
determined that SURTASS LFA sonar training, testing, and military 
operations will have no effect on the endangered or threatened species 
or their critical habitat of the ESA-listed species under the 
jurisdiction of the USFWS. Thus, no consultation with the USFWS 
pursuant to Section 7 of the ESA will occur.

National Environmental Policy Act

    NMFS has participated as a cooperating agency on the Navy's Draft 
Supplemental Environmental Impact Statement/Supplemental Overseas 
Environmental Impact Statement (DSEIS/SOEIS) for employment of SURTASS 
LFA sonar, published on August 19, 2011. The Navy's DSEIS is posted on 
the Navy's Web site at http://www.surtass-lfa-eis.com. NMFS intends to 
adopt the Navy's Final SEIS/SOEIS, if adequate and appropriate. If the 
Navy's Final SEIS/SOEIS is deemed inadequate, NMFS would supplement the 
existing analysis to ensure that we comply with NEPA prior to the 
issuance of the final rule or LOA.

Classification

    This action does not contain any collection of information 
requirements for purposes of the Paperwork Reduction Act of 1980 (44 
U.S.C. 3501 et seq.).
    The Office of Management and Budget has determined that this 
proposed rule is not significant for purposes of Executive Order 12866.
    Pursuant to the Regulatory Flexibility Act (RFA), the Chief Counsel 
for Regulation of the Department of Commerce has certified to the Chief 
Counsel for Advocacy of the Small Business Administration that this 
proposed rule, if adopted, would not have a significant economic impact 
on a substantial number of small entities. The RFA requires 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 will be affected by this rulemaking, not a small governmental 
jurisdiction, small

[[Page 888]]

organization, or small business, as defined by the RFA. Any 
requirements imposed by a Letter of Authorization issued pursuant to 
these regulations, and any monitoring or reporting requirements imposed 
by these regulations, will be applicable only to the Navy.
    NMFS does not expect the issuance of these regulations or the 
associated LOAs to result in any impacts to small entities pursuant to 
the RFA. Because this action, if adopted, would directly affect the 
Navy and not a small entity, NMFS concludes the action would not result 
in a significant economic impact on a substantial number of small 
entities.

List of Subjects in 50 CFR Part 218

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

    Dated: December 22, 2011.
 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

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

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

Subparts T Through W [Added and Reserved]

    2. Subparts T through W are added to part 218 and reserved.
    3. Subpart X is added to part 218 to read as follows:
Subpart X--Taking and Importing of Marine Mammals; Navy Operations of 
Surveillance Towed Array Sensor System Low Frequency Active (SURTASS 
LFA) Sonar
Sec.
218.230 Specified activity.
218.231 Effective dates. [Reserved]
218.232 Permissible methods of taking.
218.233 Prohibitions.
218.234 Mitigation.
218.235 Requirements for monitoring.
218.236 Requirements for reporting.
218.237 Applications for Letters of Authorization.
218.238 Letters of Authorization.
218.239 Renewal of Letters of Authorization.
218.240 Modifications to Letters of Authorization.
218.241 Adaptive Management.

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


Sec.  218.230  Specified activity.

    Regulations in this subpart apply only to the incidental taking of 
those marine mammal species specified in paragraph (b) of this section 
by the U.S. Navy, Department of Defense, while engaged in the operation 
of no more than four SURTASS LFA sonar systems conducting active sonar 
operations in areas specified in paragraph (a) of this section. The 
authorized activities, as specified in a Letter of Authorization issued 
under Sec. Sec.  216.106 and 218.238 of this chapter, include the 
transmission of low frequency sounds from the SURTASS LFA sonar system 
and the transmission of high frequency sounds from the mitigation sonar 
described in Sec.  218.234 during routine training and testing as well 
as during military operations.
    (a) The incidental take, by Level A and Level B harassment, of 
marine mammals from the activity identified in this section may be 
authorized in certain areas of the Pacific, Atlantic, and Indian Oceans 
and the Mediterranean Sea, as specified in a Letter of Authorization.
    (b) The incidental take, by Level A and Level B harassment, of 
marine mammals from the activity identified in this section is limited 
to the following species and species groups:
    (1) Mysticetes--blue whale (Balaenoptera musculus), bowhead whale 
(Balaena mysticetus), Bryde's whale (Balaenoptera edeni), fin whale 
(Balaenoptera physalus), gray whale (Eschrichtius robustus), humpback 
whale (Megaptera novaeangliae), minke whale (Balaenoptera 
acutorostrata), North Atlantic right whale (Eubalaena glacialis), North 
Pacific right whale (Eubalena japonica), pygmy right whale (Capera 
marginata), sei whale (Balaenoptera borealis), southern right whale 
(Eubalaena australis),
    (2) Odontocetes--Andrew's beaked whale (Mesoplodon bowdoini), 
Arnoux's beaked whale (Berardius arnuxii), Atlantic spotted dolphin 
(Stenella frontalis), Atlantic white-sided dolphin (Lagenorhynchus 
acutus), Baird's beaked whale (Berardius bairdii), Beluga whale 
(Dephinapterus leucas), Blainville's beaked whale (Mesoplodon 
densirostris), Chilean dolphin (Cephalorhynchus eutropia), Clymene 
dolphin (Stenella clymene), Commerson's dolphin (Cephalorhynchus 
commersonii), common bottlenose dolphin (Tursiops truncatus), Cuvier's 
beaked whale (Ziphius cavirostris), Dall's porpoise (Phocoenoides 
dalli), Dusky dolphin (Lagenorhynchus obscurus), dwarf sperm and pygmy 
sperm whales (Kogia simus and K. breviceps), false killer whale 
(Pseudorca crassidens), Fraser's dolphin (Lagenodelphis hosei), 
Gervais' beaked whale (Mesoplodon europaeus), ginkgo-toothed beaked 
whale (Mesoplodon ginkgodens), Gray's beaked whale (Mesoplodon grayi), 
Heaviside's dolphin (Cephalorhynchus heavisidii), Hector's beaked whale 
(Mesoplodon hectori), Hector's dolphin (Cephalorhynchus hectori), 
Hourglass dolphin (Lagenorhynchus cruciger), Hubbs' beaked whale 
(Mesoplodon carhubbsi), harbor porpoise (Phocoena phocoena), killer 
whale (Orca orcinus), long-beaked common dolphin (Delphinus capensis), 
long-finned pilot whale (Globicephala melas), Longman's beaked whale 
(Indopacetus pacificus), melon-headed whale (Peponocephala electra), 
northern bottlenose whale (Hyperodon ampullatus), northern right whale 
dolphin (Lissodelphis borealis), Pacific white-sided dolphin 
(Lagenorhynchus obliquidens), pantropical spotted dolphin (Stenella 
attenuata), Peale's dolphin (Lagenorhynchus australis), Perrin's beaked 
whale (Mesoplodon perrini), pygmy beaked whale (Mesoplodon peruvianus), 
pygmy killer whale (Feresa attenuata), Risso's dolphin (Grampus 
griseus), rough-toothed dolphin (Steno bredanensis), Shepherd's beaked 
whale (Tasmacetus sheperdii), short-beaked common dolphin (Delphinus 
delphis), short-finned pilot whale (Globicephala macrorhynchus), 
southern bottlenose whale (Hyperodon planifrons), southern right whale 
dolphin (Lissodelphis peronii), Sowerby's beaked whale (Mesoplodon 
bidens), spade-toothed beaked whale (Mesoplodon traversii), spectacled 
porpoise (Phocoena dioptrica), sperm whale (Physeter macrocephalus), 
spinner dolphin (Stenella longirostris), Stejneger's beaked whale 
(Mesoplodon stejnegeri), strap-toothed beaked whale (Mesoplodon 
layardii), striped dolphin (Stenella coeruleoalba), True's beaked whale 
(Mesoplodon mirus), white-beaked dolphin (Lagenorhynchus albirostris),
    (3) Pinnipeds--Australian sea lion (Neophoca cinerea), California 
sea lion (Zalophus californianus), Galapagos fur seal (Arctocephalus 
galapagoensis), Galapagos sea lion (Zalophus wollebaeki), gray seal 
(Halichoerus grypus), Guadalupe fur seal (Arctocephalus townsendi), 
harbor seal (Phoca vitulina), harp seal (Pagophilus

[[Page 889]]

groenlandicus), Hawaiian monk seal (Monachus schauinslandi), hooded 
seal (Cystophora cristata), Juan Fernadez fur seal (Arctocephalus 
philippi), Mediterranean monk seal (Monachus monachus), New Zealand fur 
seal (Arctocephalus forsteri), New Zealand fur seal (Phocarctos 
hookeri), northern elephant seal (Mirounga angustirostris), northern 
fur seal (Callorhinus ursinus), ribbon seal (Phoca fasciata), South 
African and Australian fur seals (Arctocephalus pusillus), South 
American fur seal (Arctocephalus australis), South American sea lion 
(Otaria flavescens), southern elephant seal (Mirounga leonina), spotted 
seal (Phoca largha), Steller sea lion (Eumetopias jubatus), 
subantarctic fur seal (Arctocephalus tropicalis).


Sec.  218.231  Effective dates. [Reserved]


Sec.  218.232  Permissible methods of taking.

    (a) Under Letters of Authorization issued pursuant to Sec. Sec.  
216.106 and 218.238 of this chapter, the Holder of the Letter of 
Authorization may incidentally, but not intentionally, take marine 
mammals by Level A and Level B harassment within the areas described in 
Sec.  218.230(a), provided that the activity is in compliance with all 
terms, conditions, and requirements of this subpart and the appropriate 
Letter of Authorization.
    (b) The Holder of the Letter of Authorization must conduct the 
activities identified in Sec.  218.230 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.  218.230 is limited to the species listed in Sec.  
218.230(b) by the method of take indicated in paragraphs (c)(2), 
(c)(3), (c)(4), and (c)(5) of this section.
    (1) The Navy must maintain a running calculation/estimation of 
takes of each species over the effective period of this subpart.
    (2) Level B Harassment will not exceed 12 percent of any marine 
mammal stock listed in Sec.  218.230(b)(1) through (3) annually over 
the course of the five-year regulations. This annual per-stock cap of 
12 percent applies regardless of the number of LFA vessels operating.
    (3) Level A harassment of no more than six mysticetes (total), of 
any of the species listed in Sec.  218.230(b)(1) over the course of the 
five-year regulations.
    (4) Level A harassment of no more than 25 odontocetes (total), of 
any of the species listed in Sec.  218.230(b)(2) over the course of the 
five-year regulations.
    (5) Level A harassment of no more than 25 pinnipeds (total), of any 
of the species listed in Sec.  218.230(b)(3) over the course of the 
five-year regulations.


Sec.  218.233  Prohibitions.

    No person in connection with the activities described in Sec.  
218.230 may:
    (a) Take any marine mammal not specified in Sec.  218.230(b);
    (b) Take any marine mammal specified in Sec.  218.230 other than by 
incidental take as specified in Sec.  218.232(c)(2), (c)(3), (c)(4), 
and (c)(5);
    (c) Take any marine mammal specified in Sec.  218.230 if NMFS makes 
a determination that 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, any of the terms, conditions, 
or requirements of this subpart or a Letter of Authorization issued 
under Sec.  216.106 and 218.238 of this chapter.


Sec.  218.234  Mitigation.

    The Navy must conduct the activity identified in Sec.  218.230 in a 
manner that minimizes, to the greatest extent practicable, adverse 
impacts on marine mammals and their habitats. When conducting 
operations identified in Sec.  218.230, the mitigation measures 
described in this section and in any Letter of Authorization issued 
under Sec.  216.106 and Sec.  218.238 of this chapter must be 
implemented.
    (a) Personnel Training--Lookouts: (1) The Navy shall train the 
lookouts in the most effective means to ensure quick and effective 
communication within the command structure in order to facilitate 
implementation of protective measures if they spot marine mammals.
    (2) The Navy will hire one or more marine mammal biologist 
qualified in conducting at-sea marine mammal visual monitoring from 
surface vessels to train and qualify designated ship personnel to 
conduct at-sea visual monitoring.
    (b) General Operating Procedures: (1) Prior to SURTASS LFA sonar 
operations, the Navy will promulgate executive guidance for the 
administration, execution, and compliance with the environmental 
regulations under this subpart and Letters of Authorization.
    (2) The Holder of a Letter of Authorization will not transmit the 
SURTASS LFA sonar signal at a frequency greater than 500 Hz.
    (c) LFA Mitigation Zone and 1-km Buffer Zone: (1) Prior to 
commencing and during SURTASS LFA sonar transmissions, the Holder of a 
Letter of Authorization will determine the propagation of LFA sonar 
signals in the ocean and the distance from the SURTASS LFA sonar source 
to the 180-decibel (dB) re: 1 [mu]Pa isopleth.
    (2) The Holder of a Letter of Authorization will establish an 180-
dB LFA mitigation zone around the surveillance vessel that is equal in 
size to the 180-dB re: 1 [mu]Pa isopleth (i.e., the area subjected to 
sound pressure levels of 180 dB or greater) as well as a one-kilometer 
(1-km) buffer zone around the LFA mitigation zone. If a marine mammal 
is detected, through monitoring required under Sec.  218.235, within or 
about to enter the LFA mitigation zone plus the 1-km buffer zone, the 
Holder of the Authorization will immediately delay or suspend SURTASS 
LFA sonar transmissions.
    (d) Resumption of SURTASS LFA sonar transmissions: (1) The Holder 
of a Letter of Authorization will not resume SURTASS LFA sonar 
transmissions earlier than 15 minutes after:
    (i) All marine mammals have left the area of the LFA mitigation and 
buffer zones; and
    (ii) There is no further detection of any marine mammal within the 
LFA mitigation and buffer zones as determined by the visual, passive, 
and high frequency monitoring described in Sec.  218.235.
    (2) [Reserved].
    (e) Ramp-up procedures for the high-frequency marine mammal 
monitoring (HF/M3) sonar required under Sec.  218.235: (1) The Holder 
of a Letter of Authorization will ramp up the HF/M3 sonar power level 
beginning at a maximum source sound pressure level of 180 dB: re 1 
[mu]Pa at 1 meter in 10-dB increments to operating levels over a period 
of no less than five minutes:
    (i) At least 30 minutes prior to any SURTASS LFA sonar 
transmissions;
    (ii) Prior to any SURTASS LFA sonar calibrations or testing that 
are not part of regular SURTASS LFA sonar transmissions described in 
Sec.  218.230; and
    (iii) Anytime after the HF/M3 source has been powered down for more 
than two minutes.
    (2) The Holder of a Letter of Authorization will not increase the 
HF/M3 sound pressure level once a marine mammal is detected; ramp-up 
may resume once marine mammals are no longer detected.
    (f) Geographic Restrictions on the SURTASS LFA Sonar Sound Field:
    (1) The Holder of a Letter of Authorization will not operate the 
SURTASS LFA sonar such that:
    (i) The SURTASS LFA sonar sound field exceeds 180 dB re: 1 [mu]Pa 
(rms) at a distance less than 12 nautical miles

[[Page 890]]

(nmi) (22 kilometers (km)) from any coastline, including offshore 
islands;
    (ii) The SURTASS LFA sonar sound field exceeds 180 dB re: 1 [mu]Pa 
(rms) at a distance less than 1 km (0.5 nm) seaward of the outer 
perimeter of any offshore biologically important area designated in 
Sec.  218.234(f)(1)(iii) during the period specified.
    (iii) Offshore Biologically Important Areas (OBIAs) for marine 
mammals (with specified periods) for SURTASS LFA sonar operations 
include the following:

------------------------------------------------------------------------
        Name of area            Location of area    Months of importance
------------------------------------------------------------------------
Georges Bank................  40[deg]00' N,         Year-round.
                               72[deg]30' W.
                              39[deg]37' N,
                               72[deg]09' W.
                              39[deg]54' N,
                               71[deg]43' W.
                              40[deg]02' N,
                               71[deg]20' W.
                              40[deg]08' N,
                               71[deg]01' W.
                              40[deg]04' N,
                               70[deg]44' W.
                              40[deg]00' N,
                               69[deg]24' W.
                              40[deg]16' N,
                               68[deg]27' W.
                              40[deg]34' N,
                               67[deg]13' W.
                              41[deg]00' N,
                               66[deg]24' W.
                              41[deg]52' N,
                               65[deg]47' W.
                              42[deg]20' N,
                               66[deg]06' W.
                              42[deg]18' N,
                               67[deg]23' W.
Roseway Basin Right Whale     43[deg]05' N,         June through
 Conservation Area.            65[deg]40'.           December, annually.
                              43[deg]05' N,
                               65[deg]03' W..
                              42[deg]45' N,
                               65[deg]40' W..
                              42[deg]45' N,
                               65[deg]03' W..
Great South Channel, U.S.     41[deg]00.000' N,     January 1 to
 Gulf of Maine, and            69[deg]05.000' W.     November 14,
 Stellwagen Bank National     42[deg]09.000' N,      annually.
 Marine Sanctuary (NMS).       67[deg]08.400' W..
                              42[deg]53.436' N,
                               67[deg]43.873' W..
                              44[deg]12.541' N,
                               67[deg]16.847' W..
                              44[deg]14.911' N,
                               67[deg]08.936' W..
                              44[deg]21.538' N,
                               67[deg]03.663' W..
                              44[deg]26.736' N,
                               67[deg]09.596' W..
                              44[deg]16.805' N,
                               67[deg]27.394' W..
                              44[deg]11.118' N,
                               67[deg]56.398' W..
                              43[deg]59.240' N,
                               68[deg]08.263' W..
                              43[deg]36.800' N,
                               68[deg]46.496' W..
                              43[deg]33.925' N,
                               69[deg]19.455' W..
                              43[deg]32.008' N,
                               69[deg]44.504' W..
                              43[deg]21.922' N,
                               70[deg]06.257' W..
                              43[deg]04.084' N,
                               70[deg]21.418' W..
                              42[deg]51.982' N,
                               70[deg]31.965' W..
                              42[deg]45.187' N,
                               70[deg]23.396' W..
                              42[deg]39.068' N,
                               70[deg]30.188' W..
                              42[deg]32.892' N,
                               70[deg]35.873' W..
                              42[deg]07.748' N,
                               70[deg]28.257' W..
                              42[deg]05.592' N,
                               70[deg]02.136' W..
                              42[deg]03.664' N,
                               69[deg]44.000' W..
                              41[deg]40.000' N,
                               69[deg]45.000' W..
Southeastern U.S. Right       Critical Habitat      November 15 to
 Whale Seasonal Habitat.       Boundaries are        January 15,
                               coastal waters        annually.
                               between 31[deg]15'
                               N and 30[deg]15' N
                               from the coast out
                               15 nautical miles
                               (nmi); and the
                               coastal waters
                               between 30[deg]15'
                               N and 28[deg]00' N
                               from the coast out
                               5 nmi. (50 CFR Sec.
                                 226.13(c)).
                              OBIA Boundaries are
                               coastal waters
                               between 31[deg]15'
                               N and 30[deg]15' N
                               from 12 to 15 nmi.
North Pacific Right Whale     57[deg]03' N,         March through
 Critical Habitat.             153[deg]00' W.        August, annually.
                              57[deg]18' N,
                               151[deg]30' W.
                              57[deg]00' N,
                               151[deg]30' W.
                              56[deg]45' N,
                               153[deg]00' W.
                              (50 CFR Sec.
                               226.215).
Silver Bank and Navidad Bank  Silver Bank.........  December through
                              20[deg]38.899 N,       April, annually.
                               69[deg]23.640' W.
                              20[deg]55.706' N,
                               69[deg]57.984' W.
                              20[deg]25.221' N,
                               70[deg]00.387' W.
                              20[deg]12.833' N,
                               69[deg]40.604' W.
                              20[deg]13.918' N,
                               69[deg]31.518' W.
                              20[deg]28.680' N,
                               69[deg]31.900' W.
                              Navidad Bank:.......
                              20[deg]15.596' N,
                               68[deg]47.967' W.
                              20[deg]11.971' N,
                               68[deg]54.810' W.
                              19[deg]52.514' N,
                               69[deg]00.443' W.
                              19[deg]54.957' N,
                               68[deg]51.430' W.
                              19[deg]51.513' N,
                               68[deg]41.399' W.

[[Page 891]]

 
Coastal waters of Gabon,      An exclusion zone     June through
 Congo and Equatorial Guinea.  following the 500-m   October.
                               isobath extending
                               from 3[deg]31.055'
                               N, 9[deg]12.226' E
                               in the north
                               offshore of Malabo
                               southward to
                               8[deg]57.470' S,
                               12[deg]55.873' E
                               offshore of Luanda.
Patagonian Shelf Break......  Between 200- and      Year-round.
                               2000-m isobaths and
                               the following
                               latitudes:
                               35[deg]00' S,
                               39[deg]00' S,
                               40[deg]40' S,
                               42[deg]30' S,
                               46[deg]00' S,
                               48[deg]50' S.
Southern Right Whale          Coastal waters        May through
 Seasonal Habitat.             between 42[deg]00'    December, annually.
                               S and 43[deg]00' S
                               from 12 to 15 nmi
                               including the
                               enclosed bays of
                               Golfo Nuevo, Golfo
                               San Jose and San
                               Matias. Golfos San
                               Jose and San Nuevo
                               are within 22 km
                               (12 nmi) coastal
                               exclusion zone.
Central California National   Single stratum        June through
 Marine Sanctuaries.           boundary created      November, annually.
                               from the Cordell
                               Bank (15 CFR
                               922.10), Gulf of
                               the Farallones (15
                               CFR 922.80), and
                               Monterey Bay (15
                               CFR 922.30) NMS
                               legal boundaries.
                               Monterey Bay NMS
                               includes the
                               Davidson Seamount
                               Management Zone.
Antarctic Convergence Zone..  30[deg] E to 80[deg]  October through
                               E, 45[deg] S.         March, annually.
                              80[deg] E to
                               150[deg] E, 55[deg]
                               S..
                              150[deg] E to
                               50[deg] W, 60[deg]
                               S.
                              50[deg] W to 30[deg]
                               E, 50[deg] S.
Piltun and Chayvo offshore    54[deg]09.436' N,     June through
 feeding grounds in the Sea    143[deg]47.408' W.    November, annually.
 of Okhotsk.                  54[deg]09.436' N,
                               143[deg]17.354' W..
                              54[deg]01.161' N,
                               143[deg]17.354' W.
                              53[deg]53.580' N,
                               143[deg]13.398' W.
                              53[deg]26.963' N,
                               143[deg]28.230' W.
                              53[deg]07.013' N,
                               143[deg]35.481' W.
                              52[deg]48.705' N,
                               143[deg]38.447' W.
                              52[deg]32.077' N,
                               143[deg]37.788' W.
                              52[deg]21.605' N,
                               143[deg]34.163' W.
                              52[deg]09.470' N,
                               143[deg]26.582' W.
                              51[deg]57.686' N,
                               143[deg]30.208' W.
                              51[deg]36.033' N,
                               143[deg]42.794' W.
                              51[deg]08.082' N,
                               143[deg]51.301' W.
                              51[deg]08.082' N,
                               144[deg]16.742' W.
                              51[deg]24.514' N,
                               144[deg]11.139' W.
                              51[deg]48.116' N,
                               144[deg]10.809' W.
                              52[deg]03.194' N,
                               144[deg]20.363' W.
                              52[deg]23.235' N,
                               144[deg]10.150' W.
                              52[deg]28.674' N,
                               144[deg]12.787' W.
                              52[deg]42.523' N,
                               144[deg]10.150' W.
                              53[deg]12.972' N,
                               143[deg]55.648' W.
                              53[deg]18.505' N,
                               143[deg]56.637' W.
                              53[deg]23.041' N,
                               143[deg]53.011' W.
                              53[deg]28.250' N,
                               143[deg]53.341' W.
                              53[deg]44.039' N,
                               143[deg]49.056' W.
                              53[deg]53.207' N,
                               143[deg]50.045' W.
                              53[deg]59.819' N,
                               143[deg]48.067' W.
Coastal waters off            16[deg]03'55.04'' S,  July through
 Madagascar.                   50[deg]27'12.59'' E.  September, annually
                              16[deg]12'23.03'' S,   for humpback whale
                               51[deg]03'37.38''     breeding and
                               E..                   November through
                              24[deg]30'45.06'' S,   December, annually
                               48[deg]26'00.94''     for migrating blue
                               E..                   whales.
                              24[deg]15'28.07'' S,
                               47[deg]46'51.16''
                               E..
                              22[deg]18'00.74'' S,
                               48[deg]14'13.52''
                               E..
                              20[deg]52'24.12'' S,
                               48[deg]43'13.49''
                               E..
                              19[deg]22'33.24'' S,
                               49[deg]15'45.47''
                               E..
                              18[deg]29'46.08'' S,
                               49[deg]37'32.25''
                               E..
                              17[deg]38'27.89'' S,
                               49[deg]44'27.17''
                               E..
                              17[deg]24'39.12'' S,
                               49[deg]39'17.03''
                               E..
                              17[deg]19'35.34'' S,
                               49[deg]54'23.82''
                               E..
                              16[deg]45'41.71'' S,
                               50[deg]15'56.35''
                               E..
Madagascar Plateau,           25[deg]55'20.00'' S,  November through
 Madagascar Ridge, and         44[deg]05'15.45'' E.  December, annually.
 Walters Shoal.               25[deg]46'31.36'' S,
                               47[deg]22'35.90''
                               E..
                              27[deg]02'37.71'' S,
                               48[deg]03'31.08'' E.
                              35[deg]13'51.37'' S,
                               46[deg]26'19.98'' E.
                              35[deg]14'28.59'' S,
                               42[deg]35'49.20'' E.
                              31[deg]36'57.96'' S,
                               42[deg]37'49.35'' E.
                              27[deg]41'11.21'' S,
                               44[deg]30'11.01'' E.
Ligurian-Corsican-Provencal   42[deg]50.271' N,     July to August,
 Basin and Western Pelagos     06[deg]31.883' E.     annually.
 Sanctuary in the             42[deg]55.603' N,
 Mediterranean Sea.            06[deg]43.418' E..
                              43[deg]04.374' N,
                               06[deg]52.165' E..
                              43[deg]12.600' N,
                               07[deg]10.440' E.

[[Page 892]]

 
                              43[deg]21.720' N,
                               07[deg]19.380' E.
                              43[deg]30.600' N,
                               07[deg]32.220' E.
                              43[deg]33.900' N,
                               07[deg]49.920' E.
                              43[deg]36.420' N,
                               08[deg]05.580' E.
                              43[deg]42.600' N,
                               08[deg]22.140' E.
                              43[deg]50.880' N,
                               08[deg]34.500' E.
                              43[deg]58.560' N,
                               08[deg]47.700' E.
                              43[deg]59.040' N,
                               08[deg]56.040' E.
                              43[deg]57.047' N,
                               09[deg]03.540' E.
                              43[deg]52.260' N,
                               09[deg]08.520' E.
                              43[deg]47.580' N,
                               09[deg]13.500' E.
                              43[deg]36.060' N,
                               09[deg]16.620' E.
                              43[deg]28.440' N,
                               09[deg]05.820' E.
                              43[deg]21.360' N,
                               09[deg]02.100' E.
                              43[deg]16.020' N,
                               08[deg]57.240' E.
                              43[deg]04.440' N,
                               08[deg]47.580' E.
                              42[deg]54.900' N,
                               08[deg]35.400' E.
                              42[deg]45.900' N,
                               08[deg]27.540' E.
                              42[deg]36.060' N,
                               08[deg]22.020' E.
                              42[deg]22.620' N,
                               08[deg]15.849' E.
                              42[deg]07.202' N,
                               08[deg]17.174' E.
                              41[deg]52.800' N,
                               08[deg]15.720' E.
                              41[deg]39.780' N,
                               08[deg]05.280' E.
                              41[deg]28.200' N,
                               08[deg]51.600' E.
                              42[deg]57.060' N,
                               06[deg]19.860' E.
Hawaiian Islands Humpback     21[deg]10'02.179''    November through
 Whale NMS and Penguin Bank.   N,                    April, annually.
                               157[deg]30'58.217''
                               W.
                              21[deg]09'46.815''
                               N,
                               157[deg]30'22.367''
                               W..
                              21[deg]06'39.882''
                               N,
                               157[deg]31'00.778''
                               W..
                              21[deg]02'51.976''
                               N,
                               157[deg]30'30.049''
                               W..
                              20[deg]59'52.725''
                               N,
                               157[deg]29'28.591''
                               W..
                              20[deg]58'05.174''
                               N,
                               157[deg]27'35.919''
                               W..
                              20[deg]55'49.456''
                               N,
                               157[deg]30'58.217''
                               W..
                              20[deg]50'44.729''
                               N,
                               157[deg]42'42.418''
                               W..
                              20[deg]51'02.654''
                               N,
                               157[deg]44'45.333''
                               W..
                              20[deg]53'56.784''
                               N,
                               157[deg]46'04.716''
                               W..
                              20[deg]56'32.988''
                               N,
                               157[deg]45'33.987''
                               W..
                              21[deg]01'27.472''
                               N,
                               157[deg]43'10.586''
                               W..
                              21[deg]05'20.499''
                               N,
                               157[deg]39'27.802''
                               W..
                              21[deg]10'02.179''
                               N,
                               157[deg]30'58.217''
                               W..
Costa Rica Dome.............  Centered at 9[deg] N  Year-round.
                               and 88[deg] W.
Great Barrier Reef Between    16[deg]01.829' S,     May through
 16[deg] S and 21[deg] S.      145[deg]38.783' E.    September,
                              15[deg]52.215' S,      annually.
                               146[deg]20.936' E..
                              17[deg]28.354' S,
                               146[deg]59.392' E..
                              20[deg]16.228' S,
                               151[deg]39.674' E.
                              20[deg]58.381' S,
                               150[deg]30.897' E.
                              20[deg]17.007' S,
                               149[deg]38.247' E.
                              20[deg]10.941' S,
                               149[deg]18.247' E.
                              20[deg]02.403' S,
                               149[deg]12.623' E.
                              19[deg]53.287' S,
                               149[deg]03.986' E.
                              19[deg]49.866' S,
                               148[deg]52.135' E.
                              19[deg]53.287' S,
                               148[deg]44.302' E.
                              19[deg]47.965' S,
                               148[deg]36.870' E.
                              19[deg]47.205' S,
                               148[deg]26.024' E.
                              19[deg]19.978' S,
                               147[deg]39.626' E.
                              19[deg]14.065' S,
                               147[deg]37.014' E.
                              19[deg]08.913' S,
                               147[deg]31.993' E.
                              19[deg]05.667' S,
                               147[deg]24.160' E.
                              19[deg]07.576' S,
                               147[deg]18.134' E.
                              18[deg]51.718' S,
                               146[deg]51.219' E.
                              18[deg]44.258' S,
                               146[deg]54.031' E.
                              18[deg]37.175' S,
                               146[deg]51.420' E.
                              18[deg]31.620' S,
                               146[deg]43.385' E.
                              18[deg]27.595' S,
                               146[deg]40.573' E.
                              17[deg]36.676' S,
                               146[deg]20.488' E.
                              17[deg]20.484' S,
                               146[deg]16.671' E.
                              17[deg]07.745' S,
                               146[deg]13.056' E.
                              16[deg]49.769' S,
                               146[deg]11.047' E.
                              16[deg]41.835' S,
                               146[deg]03.817' E.
                              16[deg]39.706' S,
                               145[deg]54.979' E.
Bonney Upwelling on the west  37[deg]12'20.036''    December through
 coast of Australia.           S,                    May, annually.
                               139[deg]31'17.703''
                               E.
                              37[deg]37'33.815''
                               S,
                               139[deg]42'42.508''
                               E..
                              38[deg]10'36.144''
                               S,
                               140[deg]22'57.345''
                               E..
                               38[deg]44'50.558''
                               S,
                               141[deg]33'50.342''
                               E.
                               39[deg]07'04.125''
                               S,
                               141[deg]11'00.733''
                               E.

[[Page 893]]

 
                               37[deg]28'33.179''
                               S,
                               139[deg]10'52.263''
                               E.
Northern Bay of Bengal and    20[deg]59.735' N,     Year-round.
 Head of Swatch-of-No-Ground.  89[deg]07.675' E.
                              20[deg]55.494' N,
                               89[deg]09.484' E..
                              20[deg]52.883' N,
                               89[deg]12.704' E..
                              20[deg]55.275' N,
                               89[deg]18.133' E..
                              21[deg]04.558' N,
                               89[deg]25.294' E..
                              21[deg]12.655' N,
                               89[deg]25.354' E..
                              21[deg]13.279' N,
                               89[deg]16.833' E..
                              21[deg]06.347' N,
                               89[deg]15.011' E..
Olympic Coast NMS and         Boundaries within 23  Olympic NMS:
 Prairie, Barkley Canyon,      nmi (26.5 m; 42.6     December, January,
 and Nitnat Canyon.            km) of the coast      March, and May.
                               from 47[deg]07' N
                               to 48[deg]30' N
                               latitude.
                              48[deg]30'01.995''    Prairie, Barkley
                               N,                    Canyon, and Nitnat
                               125[deg]58'38.786''   Canyon: June
                               W.                    through September.
                              48[deg]16'55.605''
                               N,
                               125[deg]38'52.052''
                               W..
                              48[deg]23'07.353''
                               N,
                               125[deg]17'10.935''
                               W..
                              48[deg]12'38.241''
                               N,
                               125[deg]16'42.339''
                               W..
                              47[deg]58'20.361''
                               N,
                               125[deg]31'14.517''
                               W..
                              47[deg]58'20.361''
                               N,
                               126[deg]06'16.322''
                               W..
                              48[deg]09'46.665''
                               N,
                               126[deg]25'48.758''
                               W..
------------------------------------------------------------------------

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


Sec.  218.235  Requirements for monitoring.

    (a) In order to mitigate the taking of marine mammals by SURTASS 
LFA sonar to the greatest extent practicable, the Holder of a Letter of 
Authorization issued pursuant to Sec. Sec.  216.106 and 218.238 of this 
chapter must:
    (1) Conduct visual monitoring from the ship's bridge during all 
daylight hours (30 minutes before sunrise until 30 minutes after 
sunset). During operations that employ SURTASS LFA sonar in the active 
mode, the SURTASS vessels shall have lookouts to maintain a topside 
watch with standard binoculars (7x) and with the naked eye.
    (2) Use low frequency passive SURTASS sonar to listen for 
vocalizing marine mammals; and
    (3) Use the HF/M3 sonar to locate and track marine mammals in 
relation to the SURTASS LFA sonar vessel and the sound field produced 
by the SURTASS LFA sonar source array.
    (b) Monitoring under paragraph (a) of this section must:
    (1) Commence at least 30 minutes before the first SURTASS LFA sonar 
transmission;
    (2) Continue between transmission pings; and
    (3) Continue either for at least 15 minutes after completion of the 
SURTASS LFA sonar transmission exercise, or, if marine mammals are 
exhibiting unusual changes in behavioral patterns, for a period of time 
until behavior patterns return to normal or conditions prevent 
continued observations.
    (c) Holders of Letters of Authorization for activities described in 
Sec.  218.230 are required to cooperate with the National Marine 
Fisheries Service and any other federal agency for monitoring the 
impacts of the activity on marine mammals.
    (d) Holders of Letters of Authorization must designate qualified 
on-site individuals to conduct the mitigation, monitoring and reporting 
activities specified in the Letter of Authorization.
    (e) Holders of Letters of Authorization must conduct all monitoring 
required under the Letter of Authorization.


Sec.  218.236  Requirements for reporting.

    (a) The Holder of the Letter of Authorization must submit 
classified and unclassified quarterly mission reports to the Director, 
Office of Protected Resources, NMFS, no later than 30 days after the 
end of each quarter beginning on the date of effectiveness of a Letter 
of Authorization or as specified in the appropriate Letter of 
Authorization. Each quarterly mission report will include all active-
mode missions completed during that quarter. At a minimum, each 
classified mission report must contain the following information:
    (1) Dates, times, and location of each vessel during each mission;
    (2) Information on sonar transmissions during each mission;
    (3) Results of the marine mammal monitoring program specified in 
the Letter of Authorization; and
    (4) Estimates of the percentages of marine mammal species and 
stocks affected (both for the quarter and cumulatively for the year) 
covered by the Letter of Authorization.
    (b) The Holder of a Letter of Authorization must submit an 
unclassified annual report to the Director, Office of Protected 
Resources, NMFS, no later than 45 days after the expiration of a Letter 
of Authorization. The reports must contain all the information required 
by the Letter of Authorization.
    (c) A final comprehensive report must be submitted to the Director, 
Office of Protected Resources, NMFS at least 240 days prior to 
expiration of this subpart. In addition to containing all the 
information required by any final year Letter of Authorization, this 
report must contain an unclassified analysis of new passive sonar 
technologies and an assessment of whether such a system is feasible as 
an alternative to SURTASS LFA sonar.
    (d) The Navy will continue to assess the data collected by its 
undersea arrays and work toward making some portion of that data, after 
appropriate security reviews, available to scientists with appropriate 
clearances. Any portions of the analyses conducted by these scientists 
based on these data that are determined to be unclassified after 
appropriate security reviews will be made publically available.


Sec.  218.237  Applications for Letters of Authorization.

    (a) To incidentally take marine mammals pursuant to this subpart, 
the U.S. Navy authority conducting the activity identified in Sec.  
218.230 must

[[Page 894]]

apply for and obtain a Letter of Authorization in accordance with Sec.  
216.106 of this chapter.
    (b) The application for a Letter of Authorization must be submitted 
to the Director, Office of Protected Resources, NMFS, at least 60 days 
before the date that either the vessel is scheduled to begin conducting 
SURTASS LFA sonar operations or the previous Letter of Authorization is 
scheduled to expire.
    (c) All applications for a Letter of Authorization must include the 
following information:
    (1) The date(s), duration, and the area(s) where the vessel's 
activity will occur;
    (2) The species and/or stock(s) of marine mammals likely to be 
found within each area;
    (3) The type of incidental taking authorization requested (i.e., 
take by Level A and/or Level B harassment);
    (4) The estimated percentage of marine mammal species/stocks 
potentially affected in each area for the period of effectiveness of 
the Letter of Authorization; and
    (5) The means of accomplishing the necessary monitoring and 
reporting that will result in increased knowledge of the species and 
the level of taking or impacts on marine mammal populations.
    (d) The National Marine Fisheries Service will review an 
application for a Letter of Authorization in accordance with Sec.  
216.104(b) of this chapter and, if adequate and complete, issue a 
Letter of Authorization.


Sec.  218.238  Letters of Authorization.

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


Sec.  218.239  Renewal of Letters of Authorization.

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


Sec.  218.240  Modifications to Letters of Authorization.

    (a) Except as provided in paragraph (b) of this section, no 
substantial modification (including withdrawal or suspension) to a 
Letter of Authorization subject to the provisions of this subpart shall 
be made by NMFS until after notification and an opportunity for public 
comment has been provided. For purposes of this paragraph, a renewal of 
a Letter of Authorization, without modification, except for the period 
of validity and a listing of planned operating areas, or for moving the 
authorized SURTASS LFA sonar system from one ship to another, is not 
considered a substantial modification.
    (b) If NMFS determines that an emergency exists that poses a 
significant risk to the well-being of the species or stocks of marine 
mammals specified in Sec.  218.230(b)(1), (2), or (3), NMFS may modify 
a Letter of Authorization without prior notice and opportunity for 
public comment. Notification will be published in the Federal Register 
within 30 days of the action.


Sec.  218.241  Adaptive Management.

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

[FR Doc. 2011-33600 Filed 1-5-12; 8:45 am]
BILLING CODE 3510-22-P