[Federal Register Volume 75, Number 98 (Friday, May 21, 2010)]
[Notices]
[Pages 28568-28587]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-12296]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XU56


Takes of Marine Mammals Incidental to Specified Activities; 
Marine Geophysical Survey in the Northwest Pacific Ocean, July Through 
September 2010

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

ACTION: Notice; proposed incidental harassment authorization; request 
for comments.

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SUMMARY: NMFS has received an application from Lamont-Doherty Earth 
Observatory (L-DEO), a part of Columbia University, for an Incidental 
Harassment Authorization (IHA) to take marine mammals, by harassment, 
incidental to conducting a marine geophysical survey at the Shatsky 
Rise in the northwest Pacific Ocean, July

[[Page 28569]]

through September, 2010. Pursuant to the Marine Mammal Protection Act 
(MMPA), NMFS is requesting comments on its proposal to issue an IHA to 
L-DEO to incidentally harass, by Level B harassment only, 34 species of 
marine mammals during the specified activity.

DATES: Comments and information must be received no later than June 21, 
2010.

ADDRESSES: Comments on the application 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. The mailbox address for 
providing e-mail comments is [email protected]. NMFS is not 
responsible for e-mail comments send to addresses other than the one 
provided here. Comments sent via e-mail, including all attachments, 
must not exceed a 10-megabyte file size.
    All comments received are a part of the public record and will 
generally be posted to http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications 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.
    A copy of the application containing a list of the references used 
in this document may be obtained by writing to the above address, 
telephoning the contact listed here (see FOR FURTHER INFORMATION 
CONTACT) or visiting the internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications. The following documents associated 
with the application are also available at same internet address: the 
National Science Foundation's (NSF) draft Environmental Assessment (EA) 
and associated report (Report) prepared by LGL Limited Environmental 
Research Associates (LGL) for NSF, titled, ``Environmental Assessment 
of a Marine Geophysical Survey by the R/V Marcus G. Langseth on the 
Shatsky Rise in the Northwest Pacific Ocean, July-September, 2010.'' 
Documents cited in this notice may be viewed, by appointment, during 
regular business hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT: Jeannine Cody, Office of Protected 
Resources, NMFS, (301) 713-2289, ext. 113 or Benjamin Laws, Office of 
Protected Resources, NMFS, (301) 713-2289, ext. 159.

SUPPLEMENTARY INFORMATION:

Background

    Section 101(a)(5)(D) of the MMPA (16 U.S.C. 1371 (a)(5)(D)) directs 
the Secretary of Commerce to authorize, upon request, the incidental, 
but not intentional, taking of small numbers of marine mammals of a 
species or population stock, by United States citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and, if the taking is 
limited to harassment, a notice of a proposed authorization is provided 
to the public for review.
    Authorization for incidental taking of small numbers of marine 
mammals 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. 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 
monitoring and reporting of such takings. 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.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the United States can apply for an authorization 
to incidentally take small numbers of marine mammals by harassment. 
Section 101(a)(5)(D) of the MMPA establishes a 45-day time limit for 
NMFS' review of an application followed by a 30-day public notice and 
comment period on any proposed authorizations for the incidental 
harassment of small numbers of marine mammals. Within 45 days of the 
close of the public comment period, NMFS must either issue or deny the 
authorization.
    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as:

Any act of pursuit, torment, or annoyance which (i) has the 
potential to injure a marine mammal or marine mammal stock in the 
wild [Level A harassment]; or (ii) has the potential to disturb a 
marine mammal or marine mammal stock in the wild by causing 
disruption of behavioral patterns, including, but not limited to, 
migration, breathing, nursing, breeding, feeding, or sheltering 
[Level B harassment].

Summary of Request

    NMFS received an application on February 2, 2010 from L-DEO for the 
taking by harassment, of marine mammals, incidental to conducting a 
marine geophysical survey in the northwest Pacific Ocean. L-DEO, with 
research funding from the U.S. National Science Foundation (NSF), plans 
to conduct a marine seismic survey in the northwest Pacific Ocean, from 
July through September, 2010.
    L-DEO plans to use one source vessel, the R/V Marcus G. Langseth 
(Langseth), a seismic airgun array, and ocean bottom seismometers (OBS) 
to conduct a geophysical survey at the Shatsky Rise, a large igneous 
plateau in the northwest Pacific Ocean. The proposed survey will 
provide data necessary to decipher the crustal structure of the Shatsky 
Rise; may address major questions of Earth history, geodynamics, and 
tectonics; could impact the understanding of terrestrial magmatism and 
mantle convection; and may obtain data that could be used to improve 
estimates of regional earthquake occurrence and distribution. In 
addition to the proposed operations of the seismic airgun array, L-DEO 
intends to operate a multibeam echosounder (MBES) and a sub-bottom 
profiler (SBP) continuously throughout the survey.
    Acoustic stimuli (i.e., increased underwater sound) generated 
during the operation of the seismic airgun array, may have the 
potential to cause marine mammals in the survey area to be behaviorally 
disturbed in a manner that NMFS considers to be Level B harassment. 
This is the principal means of marine mammal taking associated with 
these activities and L-DEO has requested an authorization to take 
several marine mammals by Level B harassment.

Description of the Specified Activity

    L-DEO's proposed seismic survey on the Shatsky Rise is scheduled to 
commence on July 24, 2010 and continue for approximately 17 days ending 
on September 7, 2010. L-DEO will operate the Langseth to deploy an 
airgun array, deploy and retrieve OBS, and tow a hydrophone streamer to 
complete the survey.
    The Langseth will depart from Apra Harbor, Guam on July 19, 2010 
for a six-day transit to the Shatsky Rise, located at 30-37[deg] N, 
154-161[deg] E in international waters offshore from Japan. Some minor 
deviation from these dates is possible, depending on logistics, weather 
conditions, and the need to repeat some lines if data quality is 
substandard. Therefore, NMFS plans to issue an

[[Page 28570]]

authorization that extends to October 21, 2010.
    Geophysical survey activities will involve conventional seismic 
methodologies to decipher the crustal structure of the Shatsky Rise. To 
obtain high-resolution, 3-D structures of the area's magmatic systems 
and thermal structures, the Langseth will deploy a towed array of 36 
airguns as an energy source and approximately 28 OBSs and a 6-kilometer 
(km) long hydrophone streamer. As the airgun array is towed along the 
survey lines, the hydrophone streamers will receive the returning 
acoustic signals and transfer the data to the vessel's onboard 
processing system. The OBSs record the returning acoustic signals 
internally for later analysis.
    The proposed Shatsky Rise study (e.g., equipment testing, startup, 
line changes, repeat coverage of any areas, and equipment recovery) 
will take place in international waters deeper than 1,000 meters (m) 
(3,280 feet (ft)) and will require approximately 17 days (d) to 
complete approximately 15 transects of variable lengths totaling 3,160 
kilometers (km) of survey lines. Data acquisition will include 
approximately 408 hours (hr) of airgun operation (17 d x 24 hr).
    The scientific team consists of Drs. Jun Korenaga (Yale University, 
New Haven, CT), William Sager (Texas A&M University, College Station, 
TX), and John Diebold (L-DEO, Palisades, NY).

Vessel Specifications

    The Langseth, owned by NSF, is a seismic research vessel with a 
propulsion system designed to be as quiet as possible to avoid 
interference with the seismic signals emanating from the airgun array. 
The vessel, which has a length of 71.5 m (235 feet (ft); a beam of 17.0 
m (56 ft); a maximum draft of 5.9 m (19 ft); and a gross tonnage of 
3,834, can accommodate up to 55 people. The ship is powered by two 
3,550 horsepower (hp) Bergen BRG-6 diesel engines which drive the two 
propellers. Each propeller has four blades and the shaft typically 
rotates at 750 revolutions per minute. The vessel also has an 800-hp 
bowthruster, which is not used during seismic acquisition. The 
operation speed during seismic acquisition is typically 7.4 to 9.3 km/
hr (3.9 to 5.0 knots (kn)) and the cruising speed of the Langseth 
outside of seismic operations is 18.5 km/hr (9.9 kn).
    The vessel also has an observation tower from which visual 
observers will watch for marine mammals before and during the proposed 
airgun operations. When stationed on the observation platform, the 
observer's eye level will be approximately 18 m (58 ft) above sea level 
providing an unobstructed view around the entire vessel.

Acoustic Source Specifications

Seismic Airguns

    The full airgun array for the proposed survey consists of 36 
airguns (a mixture of Bolt 1500LL and Bolt 1900LLX airguns ranging in 
size from 40 to 360 cubic inches (in\3\)), with a total volume of 
approximately 6,600 in\3\ and a firing pressure of 1,900 pounds per 
square inch (psi). The dominant frequency components range from two to 
188 Hertz (Hz).
    The array configuration consists of four identical linear arrays or 
strings, with 10 airguns on each string; the first and last airguns 
will be spaced 16 m (52 ft) apart. For each operating array or string, 
the Langseth crew will fire the nine airguns simultaneously. They will 
keep the tenth airgun in reserve as a spare, which will be turned on in 
case of failure of one of the other airguns. The crew will distribute 
the four airgun strings across an area measuring approximately 24 by 16 
m (79 by 52 ft) behind the Langseth and will be towed approximately 100 
m (328 ft) behind the vessel at a tow depth of nine to 12 m (29.5 to 
49.2 ft) depending on the transect. The airgun array will fire every 20 
seconds (s) for the multi-channel seismic (MCS) surveying (13 
transects) and will fire every 70 s when recording data on the OBS (2 
transects). The tow depth of the array will be 9 m (29.5 ft) for the 
MCS transects and 12 m (39.3 ft) for the OBS transects. During firing, 
the airguns will emit a brief (approximately 0.1 s) pulse of sound. The 
airguns will be silent during the intervening periods of operations.

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, and the 
units for SPLs are dB re: 1 [mu]Pa.
    SPL (in decibels (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.

Characteristics of the Airgun Pulses

    Airguns function by venting high-pressure air into the water which 
creates an air bubble. The pressure signature of an individual airgun 
consists of a sharp rise and then fall in pressure, followed by several 
positive and negative pressure excursions caused by the oscillation of 
the resulting air bubble. The oscillation of the air bubble transmits 
sounds downward through the seafloor and sounds that travel 
horizontally toward non-target areas.
    The nominal source levels of the airgun arrays used by L-DEO on the 
Langseth are 236 to 265 dB re: 1 [mu]Pa(p-p). The rms value 
for a given airgun pulse is typically 16 dB re: 1 [mu]Pa lower than the 
peak-to-peak value. Accordingly, L-DEO has predicted the received sound 
levels in relation to distance and direction from the airguns, for the 
36-airgun array and for a single 1900LL 40-in\3\ airgun, which will be 
used during power downs. A detailed description of the modeling effort 
is provided in Appendix A of LGL's Report. These are the nominal source 
levels applicable to downward propagation. The effective source levels 
for horizontal propagation are lower than those for downward 
propagation when the source consists of numerous airguns spaced apart 
from one another.
    Appendix B of LGL's report and previous Federal Register notices 
(see 69 FR 31792, June 7, 2004; 71 FR 58790, October 5, 2006; 72 FR 
71625, December 18, 2007; 73 FR 52950, September 12, 2008, or 73 FR 
71606, November 25, 2008, and 74 FR 42861, August 25, 2009) discuss the 
characteristics of the airgun pulses in detail. NMFS refers the 
reviewers to those documents for additional information.

Predicted Sound Levels for the Airguns

    Tolstoy et al., (2009) recently reported results for propagation 
measurements of pulses from the Langseth's 36-airgun array in two water 
depths, approximately 50 m and 1,600 m (164 and 5,249 ft), in the Gulf 
of Mexico in 2007 and 2008. L-DEO has used these reported empirical 
values to determine exclusion zones (EZ) for the airgun array, 
designate mitigation zones, and estimate take (described in greater 
detail

[[Page 28571]]

in Section VII of the application) for marine mammals.
    L-DEO has summarized the modeled safety radii for the planned 
airgun configuration in Table 1 which shows the measured and predicted 
distances at which sound levels (160-, 180-, and 190-dB) are expected 
to be received from the 36-airgun array and a single airgun operating 
in water greater than 1,000 m (3,820 ft) in depth.

  Table 1--Measured (Array) or Predicted (Single Airgun) Distances to Which Sound Levels >=190, 180, and 160 dB
  re: 1 [mu]Pa Could Be Received in Deep (>1000 m; 3280 ft) Water From the 36-Airgun Array, as well as a Single
Airgun, During the Proposed Shatsky Rise Seismic Survey, July-September, 2010 (Based on L-DEO Models and Tolstoy
                                                  et al., 2009)
----------------------------------------------------------------------------------------------------------------
                                                                                Predicted RMS distances (m)
                    Source and volume                       Tow depth (m) --------------------------------------
                                                                              190 dB       180 dB       160 dB
----------------------------------------------------------------------------------------------------------------
Single Bolt airgun 40 in\3\..............................          9-12 *           12           40          385
4 strings 36 airguns 6600 in\3\..........................               9          400          940         3850
                                                                       12          460         1100         4400
----------------------------------------------------------------------------------------------------------------
* The tow depth has minimal effect on the maximum near-field output and the shape of the frequency spectrum for
  the single 40-in\3\ airgun; thus the predicted safety radii are essentially the same at each tow depth.

    Results of the Gulf of Mexico calibration study (Tolstoy et al., 
2009) showed that radii around the airguns for various received levels 
varied with water depth. The tow depth of the airgun array for the 
proposed survey will range from 9 to 12 m (29.5 to 39.4 ft). However, 
in the Gulf of Mexico calibration study, the Langseth towed the airgun 
array at a depth of 6 m (19.6 ft) which is less than the tow depth 
range (9 to 12 m (29.5 to 39.4 ft)) for this proposed seismic survey. 
Accordingly, L-DEO has applied correction factors to the distances 
reported by Tolstoy et al. (2009) for shallow and intermediate depth 
water (i.e., they calculated the ratios between the 160-, 180-, and 
190-dB distances at 6 m versus 9 m (19.6 ft versus 29.5 ft) and the 
ratios between the 160-, 180-, and 190-dB distances at 6 m versus 12 m 
(19.6 ft versus 39.4 ft) from the modeled results for the 6,600-in\3\ 
airgun array). Refer to Appendix A of LGL's Environmental Assessment 
Report for additional information regarding how L-DEO calculated model 
predictions in Table 1 and how the applicant used empirical 
measurements to correct the modeled numbers.

Ocean Bottom Seismometer

    The Langseth crew will deploy approximately 28 OBS on the Shatsky 
Rise (see Figure 1 of L-DEO's application) over the course of 
approximately three days. The Langseth crew will retrieve all OBSs 
after seismic operations are completed. L-DEO expects the retrieval to 
last approximately five days.
    L-DEO proposes to use the Woods Hole Oceanographic Institution 
(WHOI) ``D2'' OBS during the cruise. This type of OBS is approximately 
one meter in height and has a maximum diameter of 50 centimeters (cm). 
The anchor (2.5 x 30.5 x 38.1 cm) is made of hot-rolled steel and 
weighs 23 kilograms (kg). The acoustic release transponder used to 
communicate with the OBS uses frequencies of 9 to 13 kHz. The source 
level of the release signal is 190 dB re: 1 [mu]Pa.

Multibeam Echosounder

    The Langseth will operate a Kongsberg EM 122 MBES concurrently 
during airgun operations to map characteristics of the ocean floor. The 
hull-mounted MBES emits brief pulses of sound (also called a ping) 
(10.5 to 13 kilohertz (kHz)) in a fan-shaped beam that extends downward 
and to the sides of the ship. The transmitting beamwidth is one or two 
degrees ([deg]) fore-aft and 150[deg] athwartship and the maximum 
source level is 242 dB re: 1 [mu]Pa.
    For deep-water operations, each ping consists of eight successive 
fan-shaped transmissions, up to 15 milliseconds (ms) in duration and 
each ensonifying a sector that extends 1[deg] fore-aft. The eight 
successive transmissions span an overall cross-track angular extent of 
about 150[deg], with 2 ms gaps between the pulses for successive 
sectors.

Sub-Bottom Profiler

    The Langseth will also operate a Knudsen 320B SBP continuously 
throughout the cruise with the MBES. An SBP operates at mid to high 
frequencies and is generally used simultaneously with an MBES to 
provide information about the sedimentary features and bottom 
topography. SBP pulses are directed downward at typical frequencies of 
approximately three to 18 kHz. However, the dominant frequency 
component of the SBP is 3.5 kHz which is directed downward in a 27[deg] 
cone by a hull-mounted transducer on the vessel. The maximum output is 
1,000 watts (204 dB re: 1 [mu]Pa), but in practice, the output varies 
with water depth. The pulse interval is one second, but a common mode 
of operation is to broadcast five pulses at 1-s intervals followed by a 
5-second pause.
    NMFS expects that acoustic stimuli resulting from the proposed 
operation of the single airgun or the 36-airgun array has the potential 
to harass marine mammals, incidental to the conduct of the proposed 
seismic survey. NMFS does not expect that the movement of the Langseth, 
during the conduct of the seismic survey, has the potential to harass 
marine mammals because of the relatively slow operation speed of the 
vessel (7.4 to 9.3 km/hr; 3.9 to 5.0 kn).

Description of the Marine Mammals in the Area of the Proposed Specified 
Activity

    Thirty-four marine mammal species may occur in the Shatsky Rise 
survey area, including 26 odontocetes (toothed cetaceans), 7 mysticetes 
(baleen whales) and one pinniped. Six of these species are listed as 
endangered under the U.S. Endangered Species Act of 1973 (ESA; 16 
U.S.C. 1531 et seq.), including the north Pacific right (Eubalena 
japonica), humpback (Megaptera novaeangliae), sei (Balaenoptera 
borealis), fin (Balaenoptera physalus), blue (Balaenoptera musculus), 
and sperm (Physeter macrocephalus) whale.
    The western North Pacific gray whale (Eschrichtius robustus) occurs 
in the northwest Pacific Ocean and is listed as endangered under the 
ESA and as critically endangered by the International Union for 
Conservation of Nature (IUCN). L-DEO does not expect to encounter this 
species within the proposed survey area as gray whales are known to 
prefer nearshore coastal waters. Thus, L-DEO does not present analysis 
for this species nor does the application request take for this 
species.

[[Page 28572]]

    Table 2 presents information on the abundance, distribution, 
population status, and conservation status of marine mammals that may 
occur in the proposed survey area.

 Table 2--Habitat, Regional Population Size, and Conservation Status of Marine Mammals That May Occur in or Near
            the Proposed Seismic Survey Area at the Shatsky Rise Area in the Northwest Pacific Ocean
----------------------------------------------------------------------------------------------------------------
                                                             Regional
            Species                     Habitat          population size     U.S. ESA     IUCN \c\    CITES \d\
                                                               \a\             \b\
----------------------------------------------------------------------------------------------------------------
Mysticetes
    North Pacific right whale.  Pelagic and coastal...  few 100 \e\......           EN           EN            I
    Humpback whale............  Mainly nearshore        938-1107 \f\.....           EN           LC            I
                                 waters and banks.
    Minke whale...............  Pelagic and coastal...  25,000 \g\.......           NL           LC            I
    Bryde's whale.............  Pelagic and coastal...  20,501 \h\.......           NL           DD            I
    Sei whale.................  Primarily offshore,     7260-12,620 \i\..           EN           EN            I
                                 pelagic.
    Fin whale.................  Continental slope,      13,620-18,680 \j\           EN           EN            I
                                 mostly pelagic.
    Blue whale................  Pelagic and coastal...  3500 \k\.........           EN           EN            I
Odontocetes
    Sperm whale...............  Usually pelagic and     29,674 \l\.......           EN           VU            I
                                 deep seas.
    Pygmy sperm whale.........  Deep waters off the     N.A..............           NL           DD           II
                                 shelf.
    Dwarf sperm whale.........  Deep waters off the     11,200 \m\.......           NL           DD           II
                                 shelf.
    Cuvier's beaked whale.....  Pelagic...............  20,000 \m\.......           NL           LC           II
    Baird's beaked whale......  Deep water............  N.A..............           NL           DD           II
    Longman's beaked whale....  Deep water............  N.A..............           NL           DD           II
    Hubb's beaked whale.......  Deep water............  25,300 \n\.......           NL           DD           II
    Ginkgo-toothed beaked       Pelagic...............  25,300 \n\.......           NL           DD           II
     whale.
    Blainville's beaked whale.  Pelagic...............  25,300 \n\.......           NL           DD           II
    Stejneger's beaked whale..  Deep water............  25,300 \n\.......           NL           DD           II
    Rough-toothed dolphin.....  Deep water............  145,900 \m\......           NL           LC           II
    Common bottlenose dolphin.  Coastal and oceanic,    168,000 \o\......           NL           LC           II
                                 shelf break.
    Pantropical spotted         Coastal and pelagic...  438,000 \o\......           NL           LC           II
     dolphin.
    Spinner dolphin)..........  Coastal and pelagic...  801,000 \p\......           NL           DD           II
    Striped dolphin...........  Off continental shelf.  570,000 \o\......           NL           LC           II
    Fraser's dolphin..........  Waters >1000 m........  289,300 \m\......           NL           LC           II
    Short-beaked common         Shelf and pelagic,      2,963,000 \q\....           NL           LC           II
     dolphin.                    seamounts.
    Pacific white-sided         Continental slope and   988,000 \r\......           NL           LC           II
     dolphin.                    pelagic.
    Northern right whale        Deep water............  307,000 \r\......           NL           LC           II
     dolphin.
    Risso's dolphin...........  Waters >1000 m,         838,000 \o\......           NL           LC           II
                                 seamounts.
    Melon-headed whale........  Oceanic...............  45,400 \m\.......           NL           LC           II
    Pygmy killer whale........  Deep, pantropical       38,900 \m\.......           NL           DD           II
                                 waters.
    False killer whale........  Pelagic...............  16,000 \o\.......           NL           DD           II
    Killer whale..............  Widely distributed....  8500 \m\.........           NL           DD           II
    Short-finned pilot whale..  Mostly pelagic, high-   53,000 \o\.......           NL           DD           II
                                 relief topography.
    Dall's porpoise...........  Deep water............  1,337,224 \s\....           NL           LC           II
Pinnipeds
    Northern fur seal.........  Coastal and pelagic...  1.1 million \t\..           NL           VU           --
----------------------------------------------------------------------------------------------------------------
N.A.--Data not available or species status was not assessed.
\a\ Region for population size, in order of preference based on available data, is Western North Pacific, North
  Pacific, or Eastern Tropical Pacific; see footnotes below.
\b\ U.S. Endangered Species Act; EN = Endangered, NL = Not listed.
\c\ Codes for IUCN (2009) classifications; EN = Endangered; VU = Vulnerable; LC = Least Concern; DD = Data
  Deficient.
\d\ Convention on International Trade in Endangered Species of Wild Fauna and Flora (UNEP-WCMC 2009): Appendix I
  = Threatened with extinction; Appendix II = not necessarily now threatened with extinction but may become so
  unless trade is closely controlled.
\e\ North Pacific (Jefferson et al., 2008).
\f\ Western North Pacific (Calambokidis et al., 2008).
\g\ Northwest Pacific and Okhotsk Sea (Buckland et al., 1992; IWC 2009).
\h\ Western North Pacific (Kitakado et al., 2008; IWC 2009).
\i\ North Pacific (Tillman, 1977).
\j\ North Pacific (Ohsumi and Wada, 1974).
\k\ North Pacific (NMFS, 1998).
\l\ Western North Pacific (Whitehead, 2002b).
\m\ Eastern Tropical Pacific (ETP) (Wade and Gerrodette, 1993).
\n\ ETP; all Mesoplodon spp. (Wade and Gerrodette, 1993).
\o\ Western North Pacific (Miyashita, 1993a).
\p\ Whitebelly spinner dolphin in the ETP in 2000 (Gerrodette et al., 2005 in Hammond et al., 2008a).
\q\ ETP (Gerrodette and Forcada 2002 in Hammond et al., 2008b).
\r\ North Pacific (Miyashita, 1993b).
\s\ North Pacific (Buckland et al., 1993).
\t\ North Pacific, 2004-2005 (Gelatt and Lowry, 2008).


[[Page 28573]]

    Refer to Section IV of L-DEO's application for detailed information 
regarding the status and distribution of these marine mammals and to 
Section III of the application for additional information regarding how 
L-DEO estimated the regional population size for the marine mammals in 
Shatsky Rise area.

Potential Effects on Marine Mammals

Summary of Potential Effects of Airgun Sounds

    Level B harassment of cetaceans and pinnipeds has the potential to 
occur during the proposed seismic survey due to acoustic stimuli caused 
by the firing of a single airgun or the 36-airgun array which 
introduces sound into the marine environment. The effects of sounds 
from airguns might include one or more of the following: Tolerance, 
masking of natural sounds, behavioral disturbance, temporary or 
permanent hearing impairment, or non-auditory physical or physiological 
effects (Richardson et al., 1995; Gordon et al., 2004; Nowacek et al., 
2007; Southall et al., 2007). Permanent hearing impairment, in the 
unlikely event that it occurred, would constitute injury, but temporary 
threshold shift (TTS) is not an injury (Southall et al., 2007). 
Although the possibility cannot be entirely excluded, it is unlikely 
that the proposed project would result in any cases of temporary or 
permanent hearing impairment, or any significant non-auditory physical 
or physiological effects. Some behavioral disturbance is expected, but 
NMFS expects the disturbance to be localized and short-term.

Tolerance

    Numerous studies have shown that pulsed sounds from airguns are 
often readily detectable in the water at distances of many kilometers. 
For a brief summary of the characteristics of airgun pulses, see 
Appendix B of L-DEO's application.
    Several studies have also shown that marine mammals at distances 
more than a few kilometers from operating seismic vessels often show no 
apparent response (tolerance) (see Appendix B (3) LGL's Report). 
Although various baleen whales, toothed whales, and (less frequently) 
pinnipeds have been shown to react behaviorally to airgun pulses under 
some conditions, at other times mammals of all three types have shown 
no overt reactions. In general, pinnipeds usually seem to be more 
tolerant of exposure to airgun pulses than cetaceans, with the relative 
responsiveness of baleen and toothed whales being variable (see 
Appendix B (5) of LGL's Report).

Masking of Natural Sounds

    The term masking refers to the inability of a subject to recognize 
the occurrence of an acoustic stimulus as a result of the interference 
of another acoustic stimulus (Clark et al., 2009). Introduced 
underwater sound may, through masking, reduce the effective 
communication distance of a marine mammal species if the frequency of 
the source is close to that used as a signal by the marine mammal, and 
if the anthropogenic sound is present for a significant fraction of the 
time (Richardson et al., 1995).
    Masking effects of pulsed sounds (even from large arrays of 
airguns) on marine mammal calls and other natural sounds are expected 
to be limited, although there are very few specific data on this. 
Because of the intermittent nature and low duty cycle of seismic airgun 
pulses, animals can emit and receive sounds in the relatively quiet 
intervals between pulses. However, in some situations, reverberation 
occurs for much or the entire interval between pulses (e.g., Simard et 
al., 2005; Clark and Gagnon, 2006) which could mask calls. Some baleen 
and toothed whales are known to continue calling in the presence of 
seismic pulses, and their calls can usually be heard between the 
seismic pulses (e.g., Richardson et al., 1986; McDonald et al., 1995; 
Greene et al., 1999; Nieukirk et al., 2004; Smultea et al., 2004; Holst 
et al., 2005a,b, 2006; and Dunn et al., 2009). However, Clark and 
Gagnon (2006) reported that fin whales in the northeast Pacific Ocean 
went silent for an extended period starting soon after the onset of a 
seismic survey in the area. Similarly, there has been one report that 
sperm whales ceased calling when exposed to pulses from a very distant 
seismic ship (Bowles et al., 1994). However, more recent studies found 
that they continued calling in the presence of seismic pulses (Madsen 
et al., 2002; Tyack et al., 2003; Smultea et al., 2004; Holst et al., 
2006; and Jochens et al., 2008). Dolphins and porpoises commonly are 
heard calling while airguns are operating (e.g., Gordon et al., 2004; 
Smultea et al., 2004; Holst et al., 2005a,b; and Potter et al., 2007). 
The sounds important to small odontocetes are predominantly at much 
higher frequencies than are the dominant components of airgun sounds, 
thus limiting the potential for masking.
    In general, NMFS expects the masking effects of seismic pulses to 
be minor, given the normally intermittent nature of seismic pulses. 
Masking effects on marine mammals are discussed further in Appendix 
B(4) of LGL's Report.

Behavioral Disturbance

    Disturbance includes a variety of effects, including subtle to 
conspicuous changes in behavior, movement, and displacement. Reactions 
to sound, if any, depend on species, state of maturity, experience, 
current activity, reproductive state, time of day, and many other 
factors (Richardson et al., 1995; Wartzok et al., 2004; Southall et 
al., 2007; Weilgart, 2007). If a marine mammal does react briefly to an 
underwater sound by changing its behavior or moving a small distance, 
the impacts of the change are unlikely to be significant to the 
individual, let alone the stock or population. However, if a sound 
source displaces marine mammals from an important feeding or breeding 
area for a prolonged period, impacts on individuals and populations 
could be significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007). 
Given the many uncertainties in predicting the quantity and types of 
impacts of noise on marine mammals, it is common practice to estimate 
how many mammals would be present within a particular distance of 
industrial activities and/or exposed to a particular level of 
industrial sound. In most cases, this approach likely overestimates the 
numbers of marine mammals that would be affected in some biologically-
important manner.
    The sound criteria used to estimate how many marine mammals might 
be disturbed to some biologically-important degree by a seismic program 
are based primarily on behavioral observations of a few species. 
Scientists have conducted detailed studies on humpback, gray, bowhead 
(Balaena mysticetus), and sperm whales. Less detailed data are 
available for some other species of baleen whales, small toothed 
whales, and sea otters (Enhydra lutris), but for many species there are 
no data on responses to marine seismic surveys.
    Baleen Whales--Baleen whales generally tend to avoid operating 
airguns, but avoidance radii are quite variable. Whales are often 
reported to show no overt reactions to pulses from large arrays of 
airguns at distances beyond a few kilometers, even though the airgun 
pulses remain well above ambient noise levels out to much longer 
distances. However, as reviewed in Appendix B (5) of the LGL report, 
baleen whales exposed to strong noise pulses from airguns often react 
by deviating from their normal migration route and/or interrupting 
their feeding and moving away. In the cases of

[[Page 28574]]

migrating gray and bowhead whales, the observed changes in behavior 
appeared to be of little or no biological consequence to the animals. 
They simply avoided the sound source by displacing their migration 
route to varying degrees, but within the natural boundaries of the 
migration corridors.
    Studies of gray, bowhead, and humpback whales have shown that 
seismic pulses with received levels of 160 to 170 dB re: 1 [mu]Pa seem 
to cause obvious avoidance behavior in a substantial fraction of the 
animals exposed (Richardson et al., 1995). In many areas, seismic 
pulses from large arrays of airguns diminish to those levels at 
distances ranging from 4 to 15 km from the source. A substantial 
proportion of the baleen whales within those distances may show 
avoidance or other strong behavioral reactions to the airgun array. 
Subtle behavioral changes sometimes become evident at somewhat lower 
received levels, and studies summarized in Appendix B (5) of the EA 
have shown that some species of baleen whales, notably bowhead and 
humpback whales, at times show strong avoidance at received levels 
lower than 160-170 dB re: 1 [mu]Pa.
    Researchers have studied the responses of humpback whales to 
seismic surveys during migration, feeding during the summer months, 
breeding while offshore from Angola, and wintering offshore from 
Brazil. McCauley et al. (1998, 2000a) studied the responses of humpback 
whales off western Australia to a full-scale seismic survey with a 16-
airgun, 2,678-in\3\ array, and to a single 20-in\3\ airgun with source 
level 227 dB re: 1 [mu]Pa(p-p). McCauley et al. (1998) 
documented that avoidance reactions began at five to eight km from the 
array, and that those reactions kept most pods approximately three to 
four km from the operating seismic boat. McCauley et al. (2000a) noted 
localized displacement during migration of four to five km by traveling 
pods and seven to 12 km by more sensitive resting pods of cow-calf 
pairs. Avoidance distances with respect to the single airgun were 
smaller but consistent with the results from the full array in terms of 
the received sound levels. The mean received level for initial 
avoidance of an approaching airgun was 140 dB re: 1 [mu]Pa for humpback 
pods containing females, and at the mean closest point of approach 
(CPA) distance the received level was 143 dB re: 1 [mu]Pa. The initial 
avoidance response generally occurred at distances of five to eight km 
from the airgun array and two km from the single airgun. However, some 
individual humpback whales, especially males, approached within 
distances of 100 to 400 m, where the maximum received level was 179 dB 
re: 1 [mu]Pa.
    Humpback whales on their summer feeding grounds in southeast Alaska 
did not exhibit persistent avoidance when exposed to seismic pulses 
from a 1.64-L (100-in\3\) airgun (Malme et al., 1985). Some humpbacks 
seemed ``startled'' at received levels of 150 to 169 dB re: 1 [mu]Pa. 
Malme et al. (1985) concluded that there was no clear evidence of 
avoidance, despite the possibility of subtle effects, at received 
levels up to 172 re: 1 [mu]Pa.
    Studies have suggested that south Atlantic humpback whales 
wintering off Brazil may be displaced or even strand upon exposure to 
seismic surveys (Engel et al., 2004). The evidence for this was 
circumstantial and subject to alternative explanations (IAGC, 2004). 
Also, the evidence was not consistent with subsequent results from the 
same area of Brazil (Parente et al., 2006), or with direct studies of 
humpbacks exposed to seismic surveys in other areas and seasons. After 
allowance for data from subsequent years, there was no observable 
direct correlation between strandings and seismic surveys (IWC, 
2007:236).
    There are no data on reactions of right whales to seismic surveys, 
but results from the closely-related bowhead whale show that their 
responsiveness can be quite variable depending on their activity 
(migrating versus feeding). Bowhead whales migrating west across the 
Alaskan Beaufort Sea in autumn, in particular, are unusually 
responsive, with substantial avoidance occurring out to distances of 20 
to 30 km from a medium-sized airgun source at received sound levels of 
around 120 to 130 dB re: 1 [mu]Pa (Miller et al., 1999; Richardson et 
al., 1999; see Appendix B (5) of LGL's report). However, more recent 
research on bowhead whales (Miller et al., 2005; Harris et al., 2007) 
corroborates earlier evidence that, during the summer feeding season, 
bowheads are not as sensitive to seismic sources. Nonetheless, subtle 
but statistically significant changes in surfacing-respiration-dive 
cycles were evident upon statistical analysis (Richardson et al. 1986). 
In the summer, bowheads typically begin to show avoidance reactions at 
received levels of about 152 to 178 dB re: 1 [mu]Pa (Richardson et al., 
1986, 1995; Ljungblad et al., 1988; Miller et al., 2005).
    Reactions of migrating and feeding (but not wintering) gray whales 
to seismic surveys have been studied. Malme et al. (1986, 1988) studied 
the responses of feeding eastern Pacific gray whales to pulses from a 
single 100-in \3\ airgun off St. Lawrence Island in the northern Bering 
Sea. They estimated, based on small sample sizes, that 50 percent of 
feeding gray whales stopped feeding at an average received pressure 
level of 173 dB re: 1 [mu]Pa on an (approximate) rms basis, and that 10 
percent of feeding whales interrupted feeding at received levels of 163 
dB re: 1 [mu]Pa. Those findings were generally consistent with the 
results of experiments conducted on larger numbers of gray whales that 
were migrating along the California coast (Malme et al., 1984; Malme 
and Miles, 1985), and western Pacific gray whales feeding off Sakhalin 
Island, Russia (Wursig et al., 1999; Gailey et al., 2007; Johnson et 
al., 2007; Yazvenko et al., 2007a,b), along with data on gray whales 
off British Columbia (Bain and Williams, 2006).
    Various species of Balaenoptera (blue, sei, fin, and minke whales) 
have occasionally been seen in areas ensonified by airgun pulses 
(Stone, 2003; MacLean and Haley, 2004; Stone and Tasker, 2006), and 
calls from blue and fin whales have been localized in areas with airgun 
operations (e.g., McDonald et al., 1995; Dunn et al., 2009). Sightings 
by observers on seismic vessels off the United Kingdom from 1997 to 
2000 suggest that, during times of good sightability, sighting rates 
for mysticetes (mainly fin and sei whales) were similar when large 
arrays of airguns were shooting vs. silent (Stone, 2003; Stone and 
Tasker, 2006). However, these whales tended to exhibit localized 
avoidance, remaining significantly further (on average) from the airgun 
array during seismic operations compared with non-seismic periods 
(Stone and Tasker, 2006). In a study off of Nova Scotia, Moulton and 
Miller (2005) found little difference in sighting rates (after 
accounting for water depth) and initial sighting distances of 
balaenopterid whales when airguns were operating vs. silent. However, 
there were indications that these whales were more likely to be moving 
away when seen during airgun operations. Similarly, ship-based 
monitoring studies of blue, fin, sei and minke whales offshore of 
Newfoundland (Orphan Basin and Laurentian Sub-basin) found no more than 
small differences in sighting rates and swim directions during seismic 
versus non-seismic periods (Moulton et al., 2005, 2006a,b).
    Data on short-term reactions by cetaceans to impulsive noises are 
not necessarily indicative of long-term or biologically significant 
effects. It is not known whether impulsive sounds affect reproductive 
rate or distribution and habitat use in subsequent days or years.

[[Page 28575]]

However, gray whales have continued to migrate annually along the west 
coast of North America with substantial increases in the population 
over recent years, despite intermittent seismic exploration (and much 
ship traffic) in that area for decades (Appendix A in Malme et al., 
1984; Richardson et al., 1995; Angliss and Allen, 2009). The western 
Pacific gray whale population did not seem affected by a seismic survey 
in its feeding ground during a previous year (Johnson et al., 2007). 
Similarly, bowhead whales have continued to travel to the eastern 
Beaufort Sea each summer, and their numbers have increased notably, 
despite seismic exploration in their summer and autumn range for many 
years (Richardson et al., 1987; Angliss and Allen, 2009).
    Toothed Whales--Little systematic information is available about 
reactions of toothed whales to noise pulses. Few studies similar to the 
more extensive baleen whale/seismic pulse work summarized above and (in 
more detail) in Appendix B of the LGL report have been reported for 
toothed whales. However, there are recent systematic studies on sperm 
whales (e.g., Gordon et al., 2006; Madsen et al., 2006; Winsor and 
Mate, 2006; Jochens et al., 2008; Miller et al., 2009). There is an 
increasing amount of information about responses of various odontocetes 
to seismic surveys based on monitoring studies (e.g., Stone, 2003; 
Smultea et al., 2004; Moulton and Miller, 2005; Bain and Williams, 
2006; Holst et al., 2006; Stone and Tasker, 2006; Potter et al., 2007; 
Hauser et al., 2008; Holst and Smultea, 2008; Weir, 2008; Barkaszi et 
al., 2009; Richardson et al., 2009).
    Seismic operators and marine mammal observers on seismic vessels 
regularly see dolphins and other small toothed whales near operating 
airgun arrays, but in general there is a tendency for most delphinids 
to show some avoidance of operating seismic vessels (e.g., Goold, 
1996a,b,c; Calambokidis and Osmek, 1998; Stone, 2003; Moulton and 
Miller, 2005; Holst et al., 2006; Stone and Tasker, 2006; Weir, 2008; 
Richardson et al., 2009; see also Barkaszi et al., 2009). Some dolphins 
seem to be attracted to the seismic vessel and floats, and some ride 
the bow wave of the seismic vessel even when large arrays of airguns 
are firing (e.g., Moulton and Miller, 2005). Nonetheless, small toothed 
whales more often tend to head away, or to maintain a somewhat greater 
distance from the vessel, when a large array of airguns is operating 
than when it is silent (e.g., Stone and Tasker, 2006; Weir, 2008). In 
most cases the avoidance radii for delphinids appear to be small, on 
the order of one km less, and some individuals show no apparent 
avoidance. The beluga whale (Delphinapterus leucas) is a species that 
(at least at times) shows long-distance avoidance of seismic vessels. 
Aerial surveys conducted in the southeastern Beaufort Sea during summer 
found that sighting rates of beluga whales were significantly lower at 
distances 10 to 20 km compared with 20 to 30 km from an operating 
airgun array, and observers on seismic boats in that area rarely see 
belugas (Miller et al., 2005; Harris et al., 2007).
    Captive bottlenose dolphins (Tursiops truncatus) and beluga whales 
exhibited changes in behavior when exposed to strong pulsed sounds 
similar in duration to those typically used in seismic surveys 
(Finneran et al., 2000, 2002, 2005). However, the animals tolerated 
high received levels of sound before exhibiting aversive behaviors.
    Results for porpoises depend on species. The limited available data 
suggest that harbor porpoises (Phocoena phocoena) show stronger 
avoidance of seismic operations than do Dall's porpoises (Phocoenoides 
dalli) (Stone, 2003; MacLean and Koski, 2005; Bain and Williams, 2006; 
Stone and Tasker, 2006). Dall's porpoises seem relatively tolerant of 
airgun operations (MacLean and Koski, 2005; Bain and Williams, 2006), 
although they too have been observed to avoid large arrays of operating 
airguns (Calambokidis and Osmek, 1998; Bain and Williams, 2006). This 
apparent difference in responsiveness of these two porpoise species is 
consistent with their relative responsiveness to boat traffic and some 
other acoustic sources (Richardson et al., 1995; Southall et al., 
2007).
    Most studies of sperm whales exposed to airgun sounds indicate that 
the sperm whale shows considerable tolerance of airgun pulses (e.g., 
Stone, 2003; Moulton et al., 2005, 2006a; Stone and Tasker, 2006; Weir, 
2008). In most cases the whales do not show strong avoidance, and they 
continue to call (see Appendix B of the LGL report for review). 
However, controlled exposure experiments in the Gulf of Mexico indicate 
that foraging behavior was altered upon exposure to airgun sound 
(Jochens et al., 2008; Miller et al., 2009; Tyack, 2009).
    There are almost no specific data on the behavioral reactions of 
beaked whales to seismic surveys. However, some northern bottlenose 
whales (Hyperoodon ampullatus) remained in the general area and 
continued to produce high-frequency clicks when exposed to sound pulses 
from distant seismic surveys (Gosselin and Lawson, 2004; Laurinolli and 
Cochrane, 2005; Simard et al., 2005). Most beaked whales tend to avoid 
approaching vessels of other types (e.g., Wursig et al., 1998). They 
may also dive for an extended period when approached by a vessel (e.g., 
Kasuya, 1986), although it is uncertain how much longer such dives may 
be as compared to dives by undisturbed beaked whales, which also are 
often quite long (Baird et al., 2006; Tyack et al., 2006). Based on a 
single observation, Aguilar-Soto et al. (2006) suggested that foraging 
efficiency of Cuvier's beaked whales may be reduced by close approach 
of vessels. In any event, it is likely that most beaked whales would 
also show strong avoidance of an approaching seismic vessel, although 
this has not been documented explicitly.
    There are increasing indications that some beaked whales tend to 
strand when naval exercises involving mid-frequency sonar operation are 
ongoing nearby (e.g., Simmonds and Lopez-Jurado, 1991; Frantzis, 1998; 
NOAA and USN, 2001; Jepson et al., 2003; Hildebrand, 2005; Barlow and 
Gisiner, 2006; see also the Strandings and Mortality subsection in this 
notice). These strandings are apparently a disturbance response, 
although auditory or other injuries or other physiological effects may 
also be involved. Whether beaked whales would ever react similarly to 
seismic surveys is unknown (see the Strandings and Mortality subsection 
in this notice). Seismic survey sounds are quite different from those 
of the sonar in operation during the above-cited incidents. Odontocete 
reactions to large arrays of airguns are variable and, at least for 
delphinids and Dall's porpoises, seem to be confined to a smaller 
radius than has been observed for the more responsive of the 
mysticetes, belugas, and harbor porpoises (Appendix B of the LGL 
Report).

Hearing Impairment and Other Physical Effects

    Temporary or permanent hearing impairment is a possibility when 
marine mammals are exposed to very strong sounds. TTS has been 
demonstrated and studied in certain captive odontocetes and pinnipeds 
exposed to strong sounds (reviewed in Southall et al., 2007). However, 
there has been no specific documentation of TTS let alone permanent 
hearing damage, i.e., permanent threshold shift (PTS), in free-ranging 
marine mammals exposed to sequences of airgun pulses during realistic 
field conditions.
    L-DEO has included exclusion (i.e., shut-down) zones for the 
proposed

[[Page 28576]]

seismic survey on the Shatsky Rise to minimize the exposure of marine 
mammals to levels of sound associated with hearing impairment.
    Several aspects of the planned monitoring and mitigation measures 
for this project are designed to detect marine mammals occurring near 
the airgun array, and to avoid exposing them to sound pulses that 
might, at least in theory, cause hearing impairment (see below this 
section). In addition, many cetaceans show some avoidance of the area 
where received levels of airgun sound are high enough such that hearing 
impairment could potentially occur. In those cases, the avoidance 
responses of the animals themselves will reduce or (most likely) avoid 
any possibility of hearing impairment.
    Non-auditory physical effects may also occur in marine mammals 
exposed to strong underwater pulsed sound. Possible types of non-
auditory physiological effects or injuries that might (in theory) occur 
in mammals close to a strong sound source include stress, neurological 
effects, bubble formation, and other types of organ or tissue damage. 
It is possible that some marine mammal species (i.e., beaked whales) 
may be especially susceptible to injury and/or stranding when exposed 
to strong transient sounds. However, as discussed below this section, 
there is no definitive evidence that any of these effects occur even 
for marine mammals in close proximity to large arrays of airguns. It is 
unlikely that any effects of these types would occur during the present 
project given the brief duration of exposure of any given mammal, the 
deep water in the study area, and the planned monitoring and mitigation 
measures. The following subsections discuss in somewhat more detail the 
possibilities of TTS, PTS, and non-auditory physical effects.
    Temporary Threshold Shift--TTS is the mildest form of hearing 
impairment that can occur during exposure to a strong sound (Kryter, 
1985). While experiencing TTS, the hearing threshold rises and a sound 
must be stronger in order to be heard. At least in terrestrial mammals, 
TTS can last from minutes or hours to (in cases of strong TTS) days. 
For sound exposures at or somewhat above the TTS threshold, hearing 
sensitivity in both terrestrial and marine mammals recovers rapidly 
after exposure to the noise ends. Few data on sound levels and 
durations necessary to elicit mild TTS have been obtained for marine 
mammals, and none of the published data concern TTS elicited by 
exposure to multiple pulses of sound. Available data on TTS in marine 
mammals are summarized in Southall et al. (2007). The distances from 
the Langseth's airguns at which the received energy level (per pulse, 
flat-weighted) that would be expected to be greater than or equal to 
180 dB re: 1 [micro]Pa are estimated in Table 1.
    The above TTS information for odontocetes is derived from studies 
on the bottlenose dolphin and beluga. For the one harbor porpoise 
tested, the received level of airgun sound that elicited onset of TTS 
was lower (Lucke et al., 2009). If these results from a single animal 
are representative, it is inappropriate to assume that onset of TTS 
occurs at similar received levels in all odontocetes (cf. Southall et 
al., 2007). Some cetaceans apparently can incur TTS at considerably 
lower sound exposures than are necessary to elicit TTS in the beluga or 
bottlenose dolphin.
    For baleen whales, there are no data, direct or indirect, on levels 
or properties of sound that are required to induce TTS. The frequencies 
to which baleen whales are most sensitive are assumed to be lower than 
those to which odontocetes are most sensitive, and natural background 
noise levels at those low frequencies tend to be higher. As a result, 
auditory thresholds of baleen whales within their frequency band of 
best hearing are believed to be higher (less sensitive) than are those 
of odontocetes at their best frequencies (Clark and Ellison, 2004). 
From this, it is suspected that received levels causing TTS onset may 
also be higher in baleen whales (Southall et al., 2007). For this 
proposed study, L-DEO expects no cases of TTS given three 
considerations: (1) The low abundance of baleen whales in the planned 
study area at the time of the survey; (2) the strong likelihood that 
baleen whales would avoid the approaching airguns (or vessel) before 
being exposed to levels high enough for TTS to occur; and (3) the 
mitigation measures that are planned.
    Permanent Threshold Shift--When PTS occurs, there is physical 
damage to the sound receptors in the ear. In severe cases, there can be 
total or partial deafness, whereas in other cases, the animal has an 
impaired ability to hear sounds in specific frequency ranges (Kryter, 
1985). There is no specific evidence that exposure to pulses of airgun 
sound can cause PTS in any marine mammal, even with large arrays of 
airguns. However, given the possibility that mammals close to an airgun 
array might incur at least mild TTS, there has been further speculation 
about the possibility that some individuals occurring very close to 
airguns might incur PTS (e.g., Richardson et al., 1995, p. 372ff; 
Gedamke et al., 2008). Single or occasional occurrences of mild TTS are 
not indicative of permanent auditory damage, but repeated or (in some 
cases) single exposures to a level well above that causing TTS onset 
might elicit PTS.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, but are assumed to be similar to those in humans and 
other terrestrial mammals. PTS might occur at a received sound level at 
least several decibels above that inducing mild TTS if the animal were 
exposed to strong sound pulses with rapid rise time--see Appendix B(6) 
of LGL's Report. Based on data from terrestrial mammals, a 
precautionary assumption is that the PTS threshold for impulse sounds 
(such as airgun pulses as received close to the source) is at least 6 
dB higher than the TTS threshold on a peak-pressure basis, and probably 
greater than six dB (Southall et al., 2007).
    Given the higher level of sound necessary to cause PTS as compared 
with TTS, it is considerably less likely that PTS would occur. Baleen 
whales generally avoid the immediate area around operating seismic 
vessels, as do some other marine mammals. The planned monitoring and 
mitigation measures, including visual monitoring, passive acoustic 
monitoring (PAM) to complement visual observations (if practicable), 
power downs, and shut downs of the airguns when mammals are seen within 
or approaching the ``exclusion zones,'' will further reduce the 
probability of exposure of marine mammals to sounds strong enough to 
induce PTS.
    Stranding and Mortality--Marine mammals close to underwater 
detonations of high explosives can be killed or severely injured, and 
the auditory organs are especially susceptible to injury (Ketten et 
al., 1993; Ketten, 1995). However, explosives are no longer used for 
marine waters for commercial seismic surveys or (with rare exceptions) 
for seismic research; they have been replaced entirely by airguns or 
related non-explosive pulse generators. Airgun pulses are less 
energetic and have slower rise times, and there is no specific evidence 
that they can cause serious injury, death, or stranding even in the 
case of large airgun arrays. However, the association of strandings of 
beaked whales with naval exercises involving mid-frequency active sonar 
and, in one case, an L-DEO seismic survey (Malakoff, 2002; Cox et al., 
2006), has raised the possibility that beaked whales exposed to strong 
``pulsed'' sounds may be especially susceptible to injury and/or 
behavioral reactions that can lead to stranding (e.g., Hildebrand, 
2005; Southall et al., 2007).

[[Page 28577]]

Appendix B(6) of the LGL report provides additional details.
    Specific sound-related processes that lead to strandings and 
mortality are not well documented, but may include:
    (1) Swimming in avoidance of a sound into shallow water;
    (2) a change in behavior (such as a change in diving behavior) that 
might contribute to tissue damage, gas bubble formation, hypoxia, 
cardiac arrhythmia, hypertensive hemorrhage or other forms of trauma;
    (3) a physiological change such as a vestibular response leading to 
a behavioral change or stress-induced hemorrhagic diathesis, leading in 
turn to tissue damage; and
    (4) tissue damage directly from sound exposure, such as through 
acoustically-mediated bubble formation and growth or acoustic resonance 
of tissues. Some of these mechanisms are unlikely to apply in the case 
of impulse sounds. However, there are increasing indications that gas-
bubble disease (analogous to the bends), induced in supersaturated 
tissue by a behavioral response to acoustic exposure, could be a 
pathologic mechanism for the strandings and mortality of some deep-
diving cetaceans exposed to sonar. The evidence for this remains 
circumstantial and associated with exposure to naval mid-frequency 
sonar, not seismic surveys (Cox et al., 2006; Southall et al., 2007).
    Seismic pulses and mid-frequency sonar signals are quite different, 
and some mechanisms by which sonar sounds have been hypothesized to 
affect beaked whales are unlikely to apply to airgun pulses. Sounds 
produced by airgun arrays are broadband impulses with most of the 
energy below one kHz. Typical military mid-frequency sonar emits non-
impulse sounds at frequencies of two to 10 kHz, generally with a 
relatively narrow bandwidth at any one time. A further difference 
between seismic surveys and naval exercises is that naval exercises can 
involve sound sources on more than one vessel. Thus, it is not 
appropriate to assume that there is a direct connection between the 
effects of military sonar and seismic surveys on marine mammals. 
However, evidence that sonar signals can, in special circumstances, 
lead (at least indirectly) to physical damage and mortality (e.g., 
Balcomb and Claridge, 2001; NOAA and USN, 2001; Jepson et al., 2003; 
Fern[aacute]ndez et al., 2004, 2005; Hildebrand 2005; Cox et al., 2006) 
suggests that caution is warranted when dealing with exposure of marine 
mammals to any high-intensity ``pulsed'' sound.
    There is no conclusive evidence of cetacean strandings or deaths at 
sea as a result of exposure to seismic surveys, but a few cases of 
strandings in the general area where a seismic survey was ongoing have 
led to speculation concerning a possible link between seismic surveys 
and strandings. Suggestions that there was a link between seismic 
surveys and strandings of humpback whales in Brazil (Engel et al., 
2004) were not well founded (IAGC, 2004; IWC, 2007). In September 2002, 
there was a stranding of two Cuvier's beaked whales (Ziphius 
cavirostris) in the Gulf of California, Mexico, when the L DEO vessel 
R/V Maurice Ewing was operating a 20-airgun (8,490 in \3\) in the 
general area. The link between the stranding and the seismic surveys 
was inconclusive and not based on any physical evidence (Hogarth, 2002; 
Yoder, 2002). Nonetheless, the Gulf of California incident plus the 
beaked whale strandings near naval exercises involving use of mid-
frequency sonar suggests a need for caution in conducting seismic 
surveys in areas occupied by beaked whales until more is known about 
effects of seismic surveys on those species (Hildebrand, 2005). No 
injuries of beaked whales are anticipated during the proposed study 
because of:
    (1) The high likelihood that any beaked whales nearby would avoid 
the approaching vessel before being exposed to high sound levels,
    (2) the proposed monitoring and mitigation measures, and
    (3) differences between the sound sources operated by L-DEO and 
those involved in the naval exercises associated with strandings.
    Non-auditory Physiological Effects--Non-auditory physiological 
effects or injuries that theoretically might occur in marine mammals 
exposed to strong underwater sound include stress, neurological 
effects, bubble formation, resonance, and other types of organ or 
tissue damage (Cox et al., 2006; Southall et al., 2007). Studies 
examining such effects are limited. However, resonance effects (Gentry, 
2002) and direct noise-induced bubble formations (Crum et al., 2005) 
are implausible in the case of exposure to an impulsive broadband 
source like an airgun array. If seismic surveys disrupt diving patterns 
of deep-diving species, this might perhaps result in bubble formation 
and a form of the bends, as speculated to occur in beaked whales 
exposed to sonar. However, there is no specific evidence of this upon 
exposure to airgun pulses.
    In general, very little is known about the potential for seismic 
survey sounds (or other types of strong underwater sounds) to cause 
non-auditory physical effects in marine mammals. Such effects, if they 
occur at all, would presumably be limited to short distances and to 
activities that extend over a prolonged period. The available data do 
not allow identification of a specific exposure level above which non-
auditory effects can be expected (Southall et al., 2007), or any 
meaningful quantitative predictions of the numbers (if any) of marine 
mammals that might be affected in those ways. Marine mammals that show 
behavioral avoidance of seismic vessels, including most baleen whales 
and some odontocetes, are especially unlikely to incur non-auditory 
physical effects. Also, the planned mitigation measures (section XI of 
L-DEO's application), including shut downs of the airguns will reduce 
any such effects that might otherwise occur.

Potential Effects of Other Acoustic Devices

MBES
    The Kongsberg EM 122 MBES will be operated from the source vessel 
during the planned study. Sounds from the MBES are very short pulses, 
occurring for two to 15 ms once every five to 20 s, depending on water 
depth. Most of the energy in the sound pulses emitted by this MBES is 
at frequencies near 12 kHz, and the maximum source level is 242 dB re: 
1 [mu]Pa. The beam is narrow (1 to 2[deg]) in fore-aft extent and wide 
(150[deg]) in the cross-track extent. Each ping consists of eight (in 
water greater than 1,000 m deep) or four (less than 1,000 m deep) 
successive fan-shaped transmissions (segments) at different cross-track 
angles. Any given mammal at depth near the trackline would be in the 
main beam for only one or two of the nine segments. Also, marine 
mammals that encounter the Kongsberg EM 122 are unlikely to be 
subjected to repeated pulses because of the narrow fore-aft width of 
the beam and will receive only limited amounts of pulse energy because 
of the short pulses. Animals close to the ship (where the beam is 
narrowest) are especially unlikely to be ensonified for more than one 
2-to-15 ms pulse (or two pulses if in the overlap area). Similarly, 
Kremser et al. (2005) noted that the probability of a cetacean swimming 
through the area of exposure when an MBES emits a pulse is small. The 
animal would have to pass the transducer at close range and be swimming 
at speeds similar to the vessel in order to receive the multiple pulses 
that might result in sufficient exposure to cause TTS.

[[Page 28578]]

    Navy sonars that have been linked to avoidance reactions and 
stranding of cetaceans: (1) Generally have longer pulse duration than 
the Kongsberg EM 122; and (2) are often directed close to horizontally 
versus more downward for the MBES. The area of possible influence of 
the MBES is much smaller--a narrow band below the source vessel. Also, 
the duration of exposure for a given marine mammal can be much longer 
for naval sonar. During L-DEO's operations, the individual pulses will 
be very short, and a given mammal would not receive many of the 
downward-directed pulses as the vessel passes by. Possible effects of 
an MBES on marine mammals are outlined below.
    Masking--Marine mammal communications will not be masked 
appreciably by the MBES signals given the low duty cycle of the 
echosounder and the brief period when an individual mammal is likely to 
be within its beam. Furthermore, in the case of baleen whales, the MBES 
signals (12 kHz) do not overlap with the predominant frequencies in the 
calls, which would avoid any significant masking.
    Behavioral Responses--Behavioral reactions of free-ranging marine 
mammals to sonars, echosounders, and other sound sources appear to vary 
by species and circumstance. Observed reactions have included silencing 
and dispersal by sperm whales (Watkins et al., 1985), increased 
vocalizations and no dispersal by pilot whales (Globicephala melas) 
(Rendell and Gordon, 1999), and the previously-mentioned beachings by 
beaked whales. During exposure to a 21 to 25 kHz ``whale-finding'' 
sonar with a source level of 215 dB re: 1 [micro]Pa, gray whales 
reacted by orienting slightly away from the source and being deflected 
from their course by approximately 200 m (Frankel, 2005). When a 38-kHz 
echosounder and a 150-kHz acoustic Doppler current profiler were 
transmitting during studies in the Eastern Tropical Pacific, baleen 
whales showed no significant responses, while spotted and spinner 
dolphins were detected slightly more often and beaked whales less often 
during visual surveys (Gerrodette and Pettis, 2005).
    Captive bottlenose dolphins and a beluga whale exhibited changes in 
behavior when exposed to 1-s tonal signals at frequencies similar to 
those that will be emitted by the MBES used by L DEO, and to shorter 
broadband pulsed signals. Behavioral changes typically involved what 
appeared to be deliberate attempts to avoid the sound exposure 
(Schlundt et al., 2000; Finneran et al., 2002; Finneran and Schlundt, 
2004). The relevance of those data to free-ranging odontocetes is 
uncertain, and in any case, the test sounds were quite different in 
duration as compared with those from an MBES.
    Hearing Impairment and Other Physical Effects--Given recent 
stranding events that have been associated with the operation of naval 
sonar, there is concern that mid-frequency sonar sounds can cause 
serious impacts to marine mammals (see above). However, the MBES 
proposed for use by L DEO is quite different than sonar used for navy 
operations. Pulse duration of the MBES is very short relative to the 
naval sonar. Also, at any given location, an individual marine mammal 
would be in the beam of the MBES for much less time given the generally 
downward orientation of the beam and its narrow fore-aft beamwidth; 
navy sonar often uses near-horizontally-directed sound. Those factors 
would all reduce the sound energy received from the MBES rather 
drastically relative to that from naval sonar.
    NMFS believes that the brief exposure of marine mammals to one 
pulse, or small numbers of signals, from the MBES is not likely to 
result in the harassment of marine mammals.
SBP
    Sounds from the SBP are very short pulses, occurring for one to 
four ms once every second. Most of the energy in the sound pulses 
emitted by the SBP is at 3.5 kHz, and the beam is directed downward. 
The sub-bottom profiler on the Langseth has a maximum source level of 
204 dB re: 1 [micro]Pa.
    Kremser et al. (2005) noted that the probability of a cetacean 
swimming through the area of exposure when a bottom profiler emits a 
pulse is small--even for an SBP more powerful than that on the 
Langseth--if the animal was in the area, it would have to pass the 
transducer at close range and in order to be subjected to sound levels 
that could cause TTS.
    Masking--Marine mammal communications will not be masked 
appreciably by the SBP signals given the directionality of the signal 
and the brief period when an individual mammal is likely to be within 
its beam. Furthermore, in the case of most baleen whales, the SBP 
signals do not overlap with the predominant frequencies in the calls, 
which would avoid significant masking.
    Behavioral Responses--Marine mammal behavioral reactions to other 
pulsed sound sources are discussed above, and responses to the SBP are 
likely to be similar to those for other pulsed sources if received at 
the same levels. However, the pulsed signals from the SBP are 
considerably weaker than those from the MBES. Therefore, behavioral 
responses are not expected unless marine mammals are very close to the 
source.
    Hearing Impairment and Other Physical Effects--It is unlikely that 
the SBP produces pulse levels strong enough to cause hearing impairment 
or other physical injuries even in an animal that is (briefly) in a 
position near the source. The SBP is usually operated simultaneously 
with other higher-power acoustic sources. Many marine mammals will move 
away in response to the approaching higher-power sources or the vessel 
itself before the mammals would be close enough for there to be any 
possibility of effects from the less intense sounds from the SBP. In 
the case of mammals that do not avoid the approaching vessel and its 
various sound sources, mitigation measures that would be applied to 
minimize effects of other sources would further reduce or eliminate any 
minor effects of the SBP.
OBS
    The acoustic release transponder used to communicate with the OBSs 
uses frequencies of nine to 13 kHz. Once the OBS is ready to be 
retrieved, the crew will use an acoustic release transponder to 
interrogate (i.e., send a signal) to the OBS at a frequency of nine to 
11 kHz (source level is 190 dB re: 1 [mu]Pa). The acoustic release 
transponder will then receive a response at a frequency of nine to 13 
kHz. The burn-wire release assembly activates and releases the OBS from 
the anchor to float to the surface.
    An animal would have to pass by the OBS at close range when the 
signal is emitted in order to be exposed to any pulses at a source 
level of 190 dB re: 1 [mu]Pa. The sound is expected to undergo a 
spreading loss of approximately 40 dB in the first 100 m (328 ft). 
Thus, any animals located 100 m (328 ft) or more from the signal will 
be exposed to very weak signals (less than 150 dB) that are not 
expected to have any effects. The signal is used only for short 
intervals to interrogate and trigger the release of the OBS and 
consists of pulses rather than a continuous sound. Given the short 
duration use of this signal and rapid attenuation in seawater it is 
unlikely that the acoustic release signals would significantly affect 
marine mammals through masking, disturbance, or hearing impairment. L-
DEO states that any effects likely would be negligible given the brief 
exposure at presumable low levels.

[[Page 28579]]

Anticipated Effects on Marine Mammal Habitat

    The proposed seismic survey will not result in any permanent impact 
on habitats used by marine mammals, including the food sources they 
use. 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.
    The Langseth will deploy 28 OBS on the Shatsky Rise and the 23-kg 
OBS anchors will remain upon equipment recovery. Although OBS placement 
may disrupt a very small area of seafloor habitat and may disturb 
benthic invertebrates, the impacts are expected to be localized and 
transitory. The Langseth will deploy the OBS in such a way that creates 
the least disturbance to the area. Although OBS placement will disrupt 
a very small area of seafloor habitat and could disturb benthic 
invertebrates, L-DEO does not anticipate any significant impacts to the 
habitats used by the 34 species of marine mammals in the Shatsky Rise 
area.

Anticipated Effects on Fish

    One reason for the adoption of airguns as the standard energy 
source for marine seismic surveys is that, unlike explosives, they have 
not been associated with large-scale fish kills. However, existing 
information on the impacts of seismic surveys on marine fish 
populations is limited (see Appendix D of the LGL Report). There are 
three types of potential effects of exposure to seismic surveys: (1) 
Pathological, (2) physiological, and (3) behavioral. Pathological 
effects involve lethal and temporary or permanent sub-lethal injury. 
Physiological effects involve temporary and permanent primary and 
secondary stress responses, such as changes in levels of enzymes and 
proteins. Behavioral effects refer to temporary and (if they occur) 
permanent changes in exhibited behavior (e.g., startle and avoidance 
behavior). The three categories are interrelated in complex ways. For 
example, it is possible that certain physiological and behavioral 
changes could potentially lead to an ultimate pathological effect on 
individuals (i.e., mortality).
    The specific received sound levels at which permanent adverse 
effects to fish potentially could occur are little studied and largely 
unknown. Furthermore, the available information on the impacts of 
seismic surveys on marine fish is from studies of individuals or 
portions of a population; there have been no studies at the population 
scale. The studies of individual fish have often been on caged fish 
that were exposed to airgun pulses in situations not representative of 
an actual seismic survey. Thus, available information provides limited 
insight on possible real-world effects at the ocean or population 
scale. This makes drawing conclusions about impacts on fish problematic 
because, ultimately, the most important issues concern effects on 
marine fish populations, their viability, and their availability to 
fisheries.
    The specific received sound levels at which permanent adverse 
effects to fish potentially could occur are little studied and largely 
unknown. Furthermore, the available information on the impacts of 
seismic surveys on marine fish is from studies of individuals or 
portions of a population; there have been no studies at the population 
scale. The studies of individual fish have often been on caged fish 
that were exposed to airgun pulses in situations not representative of 
an actual seismic survey. Thus, available information provides limited 
insight on possible real-world effects at the ocean or population 
scale. This makes drawing conclusions about impacts on fish problematic 
because, ultimately, the most important issues concern effects on 
marine fish populations, their viability, and their availability to 
fisheries.
    Hastings and Popper (2005), Popper (2009), and Popper and Hastings 
(2009a,b) provided recent critical reviews of the known effects of 
sound on fish. The following sections provide a general synopsis of the 
available information on the effects of exposure to seismic and other 
anthropogenic sound as relevant to fish. The information comprises 
results from scientific studies of varying degrees of rigor plus some 
anecdotal information. Some of the data sources may have serious 
shortcomings in methods, analysis, interpretation, and reproducibility 
that must be considered when interpreting their results (see Hastings 
and Popper, 2005). Potential adverse effects of the program's sound 
sources on marine fish are then noted.
    Pathological Effects--The potential for pathological damage to 
hearing structures in fish depends on the energy level of the received 
sound and the physiology and hearing capability of the species in 
question (see Appendix D of the LGL Report). For a given sound to 
result in hearing loss, the sound must exceed, by some substantial 
amount, the hearing threshold of the fish for that sound (Popper, 
2005). The consequences of temporary or permanent hearing loss in 
individual fish on a fish population are unknown; however, they likely 
depend on the number of individuals affected and whether critical 
behaviors involving sound (e.g., predator avoidance, prey capture, 
orientation and navigation, reproduction, etc.) are adversely affected.
    Little is known about the mechanisms and characteristics of damage 
to fish that may be inflicted by exposure to seismic survey sounds. Few 
data have been presented in the peer-reviewed scientific literature. As 
far as we know, there are only two papers with proper experimental 
methods, controls, and careful pathological investigation implicating 
sounds produced by actual seismic survey airguns in causing adverse 
anatomical effects. One such study indicated anatomical damage, and the 
second indicated TTS in fish hearing. The anatomical case is McCauley 
et al. (2003), who found that exposure to airgun sound caused 
observable anatomical damage to the auditory maculae of ``pink 
snapper'' (Pagrus auratus). This damage in the ears had not been 
repaired in fish sacrificed and examined almost two months after 
exposure. On the other hand, Popper et al. (2005) documented only TTS 
(as determined by auditory brainstem response) in two of three fish 
species from the Mackenzie River Delta. This study found that broad 
whitefish (Coregonus nasus) that received a sound exposure level of 177 
dB re 1 [micro]Pa\2\ [middot] s showed no hearing loss. During both 
studies, the repetitive exposure to sound was greater than would have 
occurred during a typical seismic survey. However, the substantial low-
frequency energy produced by the airguns [less than 400 Hz in the study 
by McCauley et al. (2003) and less than approximately 200 Hz in Popper 
et al. (2005)] likely did not propagate to the fish because the water 
in the study areas was very shallow (approximately 9 m in the former 
case and less than two m in the latter). Water depth sets a lower limit 
on the lowest sound frequency that will propagate (the ``cutoff 
frequency'') at about one-quarter wavelength (Urick, 1983; Rogers and 
Cox, 1988).
    Wardle et al. (2001) suggested that in water, acute injury and 
death of organisms exposed to seismic energy depends primarily on two 
features of the sound source: (1) The received peak pressure and (2) 
the time required for the pressure to rise and decay. Generally, as 
received pressure increases, the period for the pressure to rise and 
decay decreases, and the chance of acute pathological effects 
increases. According to Buchanan et al. (2004), for the types of 
seismic airguns and arrays involved with the proposed program, the 
pathological (mortality)

[[Page 28580]]

zone for fish would be expected to be within a few meters of the 
seismic source. Numerous other studies provide examples of no fish 
mortality upon exposure to seismic sources (Falk and Lawrence, 1973; 
Holliday et al., 1987; La Bella et al., 1996; Santulli et al., 1999; 
McCauley et al., 2000a,b, 2003; Bjarti, 2002; Thomsen, 2002; Hassel et 
al., 2003; Popper et al., 2005; Boeger et al., 2006).
    Some studies have reported, some equivocally, that mortality of 
fish, fish eggs, or larvae can occur close to seismic sources 
(Kostyuchenko, 1973; Dalen and Knutsen, 1986; Booman et al., 1996; 
Dalen et al., 1996). Some of the reports claimed seismic effects from 
treatments quite different from actual seismic survey sounds or even 
reasonable surrogates. However, Payne et al. (2009) reported no 
statistical differences in mortality/morbidity between control and 
exposed groups of capelin eggs or monkfish larvae. Saetre and Ona 
(1996) applied a `worst-case scenario' mathematical model to 
investigate the effects of seismic energy on fish eggs and larvae. They 
concluded that mortality rates caused by exposure to seismic surveys 
are so low, as compared to natural mortality rates, that the impact of 
seismic surveying on recruitment to a fish stock must be regarded as 
insignificant.
    Physiological Effects--Physiological effects refer to cellular and/
or biochemical responses of fish to acoustic stress. Such stress 
potentially could affect fish populations by increasing mortality or 
reducing reproductive success. Primary and secondary stress responses 
of fish after exposure to seismic survey sound appear to be temporary 
in all studies done to date (Sverdrup et al., 1994; Santulli et al., 
1999; McCauley et al., 2000a,b). The periods necessary for the 
biochemical changes to return to normal are variable and depend on 
numerous aspects of the biology of the species and of the sound 
stimulus (see Appendix D of the LGL Report).
    Behavioral Effects--Behavioral effects include changes in the 
distribution, migration, mating, and catchability of fish populations. 
Studies investigating the possible effects of sound (including seismic 
survey sound) on fish behavior have been conducted on both uncaged and 
caged individuals (e.g., Chapman and Hawkins, 1969; Pearson et al., 
1992; Santulli et al., 1999; Wardle et al., 2001; Hassel et al., 2003). 
Typically, in these studies fish exhibited a sharp ``startle'' response 
at the onset of a sound followed by habituation and a return to normal 
behavior after the sound ceased.
    There is general concern about potential adverse effects of seismic 
operations on fisheries, namely a potential reduction in the 
``catchability'' of fish involved in fisheries. Although reduced catch 
rates have been observed in some marine fisheries during seismic 
testing, in a number of cases the findings are confounded by other 
sources of disturbance (Dalen and Raknes, 1985; Dalen and Knutsen, 
1986; L[oslash]kkeborg, 1991; Skalski et al., 1992; Eng[aring]s et al., 
1996). In other airgun experiments, there was no change in catch per 
unit effort (CPUE) of fish when airgun pulses were emitted, 
particularly in the immediate vicinity of the seismic survey (Pickett 
et al., 1994; La Bella et al., 1996). For some species, reductions in 
catch may have resulted from a change in behavior of the fish, e.g., a 
change in vertical or horizontal distribution, as reported in Slotte et 
al. (2004).
    In general, any adverse effects on fish behavior or fisheries 
attributable to seismic testing may depend on the species in question 
and the nature of the fishery (season, duration, fishing method). They 
may also depend on the age of the fish, its motivational state, its 
size, and numerous other factors that are difficult, if not impossible, 
to quantify at this point, given such limited data on effects of 
airguns on fish, particularly under realistic at-sea conditions.

Anticipated Effects on Invertebrates

    The existing body of information on the impacts of seismic survey 
sound on marine invertebrates is very limited. However, there is some 
unpublished and very limited evidence of the potential for adverse 
effects on invertebrates, thereby justifying further discussion and 
analysis of this issue. The three types of potential effects of 
exposure to seismic surveys on marine invertebrates are pathological, 
physiological, and behavioral. Based on the physical structure of their 
sensory organs, marine invertebrates appear to be specialized to 
respond to particle displacement components of an impinging sound field 
and not to the pressure component (Popper et al., 2001; see also 
Appendix E of the LGL Report).
    The only information available on the impacts of seismic surveys on 
marine invertebrates involves studies of individuals; there have been 
no studies at the population scale. Thus, available information 
provides limited insight on possible real-world effects at the regional 
or ocean scale. The most important aspect of potential impacts concerns 
how exposure to seismic survey sound ultimately affects invertebrate 
populations and their viability, including availability to fisheries.
    Literature reviews of the effects of seismic and other underwater 
sound on invertebrates were provided by Moriyasu et al. (2004) and 
Payne et al. (2008). The following sections provide a synopsis of 
available information on the effects of exposure to seismic survey 
sound on species of decapod crustaceans and cephalopods, the two 
taxonomic groups of invertebrates on which most such studies have been 
conducted. The available information is from studies with variable 
degrees of scientific soundness and from anecdotal information. A more 
detailed review of the literature on the effects of seismic survey 
sound on invertebrates is provided in Appendix E of the LGL Report.
    Pathological Effects--In water, lethal and sub-lethal injury to 
organisms exposed to seismic survey sound appears to depend on at least 
two features of the sound source: (1) The received peak pressure; and 
(2) the time required for the pressure to rise and decay. Generally, as 
received pressure increases, the period for the pressure to rise and 
decay decreases, and the chance of acute pathological effects 
increases. For the type of airgun array planned for the proposed 
program, the pathological (mortality) zone for crustaceans and 
cephalopods is expected to be within a few meters of the seismic 
source, at most; however, very few specific data are available on 
levels of seismic signals that might damage these animals. This premise 
is based on the peak pressure and rise/decay time characteristics of 
seismic airgun arrays currently in use around the world.
    Some studies have suggested that seismic survey sound has a limited 
pathological impact on early developmental stages of crustaceans 
(Pearson et al., 1994; Christian et al., 2003; DFO, 2004). However, the 
impacts appear to be either temporary or insignificant compared to what 
occurs under natural conditions. Controlled field experiments on adult 
crustaceans (Christian et al., 2003, 2004; DFO, 2004) and adult 
cephalopods (McCauley et al., 2000a,b) exposed to seismic survey sound 
have not resulted in any significant pathological impacts on the 
animals. It has been suggested that exposure to commercial seismic 
survey activities has injured giant squid (Guerra et al., 2004), but 
the article provides little evidence to support this claim.
    Physiological Effects--Physiological effects refer mainly to 
biochemical

[[Page 28581]]

responses by marine invertebrates to acoustic stress. Such stress 
potentially could affect invertebrate populations by increasing 
mortality or reducing reproductive success. Primary and secondary 
stress responses (i.e., changes in haemolymph levels of enzymes, 
proteins, etc.) of crustaceans have been noted several days or months 
after exposure to seismic survey sounds (Payne et al., 2007). The 
periods necessary for these biochemical changes to return to normal are 
variable and depend on numerous aspects of the biology of the species 
and of the sound stimulus.
    Behavioral Effects--There is increasing interest in assessing the 
possible direct and indirect effects of seismic and other sounds on 
invertebrate behavior, particularly in relation to the consequences for 
fisheries. Changes in behavior could potentially affect such aspects as 
reproductive success, distribution, susceptibility to predation, and 
catchability by fisheries. Studies investigating the possible 
behavioral effects of exposure to seismic survey sound on crustaceans 
and cephalopods have been conducted on both uncaged and caged animals. 
In some cases, invertebrates exhibited startle responses (e.g., squid 
in McCauley et al., 2000a,b). In other cases, no behavioral impacts 
were noted (e.g., crustaceans in Christian et al., 2003, 2004; DFO 
2004). There have been anecdotal reports of reduced catch rates of 
shrimp shortly after exposure to seismic surveys; however, other 
studies have not observed any significant changes in shrimp catch rate 
(Andriguetto-Filho et al., 2005). Similarly, Parry and Gason (2006) did 
not find any evidence that lobster catch rates were affected by seismic 
surveys. Any adverse effects on crustacean and cephalopod behavior or 
fisheries attributable to seismic survey sound depend on the species in 
question and the nature of the fishery (season, duration, fishing 
method).

Proposed Mitigation

    In order to issue an incidental take authorization (ITA) under 
Section 101(a)(5)(D) of the MMPA, NMFS must set forth the permissible 
methods of taking pursuant to such activity, and other means of 
effecting the least practicable adverse impact on such species or stock 
and its habitat, paying particular attention to rookeries, mating 
grounds, and areas of similar significance, and the availability of 
such species or stock for taking for certain subsistence uses.
    L-DEO has based the mitigation measures described herein, to be 
implemented for the proposed seismic survey, on the following:
    (1) Protocols used during previous L-DEO seismic research cruises 
as approved by NMFS;
    (2) previous IHA applications and IHAs approved and authorized by 
NMFS; and
    (3) recommended best practices in Richardson et al. (1995), Pierson 
et al. (1998), and Weir and Dolman, (2007).
    To reduce the potential for disturbance from acoustic stimuli 
associated with the activities, L-DEO and/or its designees has proposed 
to implement the following mitigation measures for marine mammals:
    (1) Proposed exclusion zones;
    (2) power-down procedures;
    (3) shutdown procedures, including procedures for species of 
concern such as emergency shut-down procedures for North Pacific right 
whales; and
    (4) ramp-up procedures.
    Proposed Exclusion Zones--During the proposed study, all proposed 
survey effort will take place in deep (greater than 1,000 m) water. L-
DEO uses safety radii to designate exclusion zones and to estimate take 
(described in greater detail in Section VII of the application) for 
marine mammals. Table 1 shows the distances at which three sound levels 
(160-, 180-, and 190-dB) are expected to be received from the 36-airgun 
array and a single airgun. The 180- and 190-dB levels are shut-down 
criteria applicable to cetaceans and pinnipeds, respectively, as 
specified by NMFS (2000); and L-DEO used these levels to establish the 
EZs. If the protected species visual observer (PSVO) detects marine 
mammal(s) within or about to enter the appropriate EZ, the Langseth 
crew will immediately power down the airguns, or perform a shut down if 
necessary (see Shut-down Procedures).
    Power-down Procedures--A power down involves decreasing the number 
of airguns in use such that the radius of the 180-dB zone is decreased 
to the extent that marine mammals are no longer in or about to enter 
the EZ. A power down of the airgun array can also occur when the vessel 
is moving from one seismic line to another. During a power down for 
mitigation, L-DEO will operate one airgun. The continued operation of 
one airgun is intended to alert marine mammals to the presence of the 
seismic vessel in the area. In contrast, a shut down occurs when the 
Langseth suspends all airgun activity.
    If the PSVO detects a marine mammal (other than a north Pacific 
right whale--see Shut-down Procedures) outside the EZ, but it is likely 
to enter the EZ, L-DEO will power down the airguns before the animal is 
within the EZ. Likewise, if a mammal is already within the EZ, when 
first detected, L-DEO will power down the airguns immediately. During a 
power down of the airgun array, L-DEO will also operate the 40-in\3\ 
airgun. If a marine mammal is detected within or near the smaller EZ 
around that single airgun (Table 1), L-DEO will shut down the airgun 
(see next Section).
    Following a power down, L-DEO will not resume airgun activity until 
the marine mammal has cleared the safety zone. L-DEO will consider the 
animal to have cleared the EZ if
     A PSVO has visually observed the animal leave the EZ, or
     A PSVO has not sighted the animal within the EZ for 15 min 
for small odontocetes (or pinnipeds), or 30 min for mysticetes and 
large odontocetes, including sperm, pygmy sperm, dwarf sperm, and 
beaked whales.
    During airgun operations following a power down (or shut down) 
whose duration has exceeded the time limits specified previously, L-DEO 
will ramp-up the airgun array gradually (see Shut-down Procedures).
    Shut-down Procedures--L-DEO will shut down the operating airgun(s) 
if a marine mammal is seen within or approaching the EZ for the single 
airgun. L-DEO will implement a shut down:
    (1) If an animal enters the EZ of the single airgun after L-DEO has 
initiated a power down, or (2) if a an animal is initially seen within 
the EZ of the single airgun when more than one airgun (typically the 
full airgun array) is operating.
    L-DEO will not resume airgun activity until the marine mammal has 
cleared the EZ, or until the PSVO is confident that the animal has left 
the vicinity of the vessel. Criteria for judging that the animal has 
cleared the EZ will be as described in the preceding section.
    Considering the conservation status for North Pacific right whales, 
L-DEO will shut down the airgun(s) immediately in the unlikely event 
that this species is observed, regardless of the distance from the 
Langseth. L-DEO will only begin a ramp-up if the right whale has not 
been seen for 30 min.
    Ramp-up Procedures--L-DEO will follow a ramp-up procedure when the 
airgun array begins operating after a specified period without airgun 
operations or when a power down has exceeded that period. L-DEO 
proposes that, for the present cruise, this period would be 
approximately eight min. This period is based on the 180-dB radius (940 
m, 3,084 ft) for the 36-airgun array towed at a depth of nine m in 
relation

[[Page 28582]]

to the minimum planned speed of the Langseth while shooting (7.4 km/h, 
4.6 mi/hr). Similar periods (approximately eight to ten min) were used 
during previous L-DEO surveys.
    Ramp-up will begin with the smallest airgun in the array (40-
in\3\). Airguns will be added in a sequence such that the source level 
of the array will increase in steps not exceeding six dB per five-
minute period over a total duration of approximately 35 min. During 
ramp-up, the PSVOs will monitor the EZ, and if marine mammals are 
sighted, L-DEO will implement a power down or shut down as though the 
full airgun array were operational.
    If the complete EZ has not been visible for at least 30 min prior 
to the start of operations in either daylight or nighttime, L-DEO will 
not commence the ramp-up unless at least one airgun (40-in\3\ or 
similar) has been operating during the interruption of seismic survey 
operations. Given these provisions, it is likely that the airgun array 
will not be ramped up from a complete shut down at night or in thick 
fog, because the outer part of the safety zone for that array will not 
be visible during those conditions. If one airgun has operated during a 
power-down period, ramp-up to full power will be permissible at night 
or in poor visibility, on the assumption that marine mammals will be 
alerted to the approaching seismic vessel by the sounds from the single 
airgun and could move away. L-DEO will not initiate a ramp-up of the 
airguns if a marine mammal is sighted within or near the applicable EZs 
during the day or close to the vessel at night.
    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and has considered a 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: (1) 
The manner in which, and the degree to which, the successful 
implementation of the measure is expected to minimize adverse impacts 
to marine mammals; (2) the proven or likely efficacy of the specific 
measure to minimize adverse impacts as planned; and (3) the 
practicability of the measure for applicant implementation.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS or recommended by the public, 
NMFS has determined that the required mitigation measures 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.

Proposed Monitoring and Reporting

    In order to issue an ITA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking.'' The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for IHAs 
must include the suggested means of accomplishing the necessary 
monitoring and reporting that will result in increased knowledge of the 
species and of the level of taking or impacts on populations of marine 
mammals that are expected to be present in the action area.
    L-DEO proposes to sponsor marine mammal monitoring during the 
present project, in order to implement the proposed mitigation measures 
that require real-time monitoring, and to satisfy the anticipated 
monitoring requirements of the IHA. L-DEO's proposed Monitoring Plan is 
described below this section. L-DEO understands that this monitoring 
plan will be subject to review by NMFS, and that refinements may be 
required. The monitoring work described here has been planned as a 
self-contained project independent of any other related monitoring 
projects that may be occurring simultaneously in the same regions. L-
DEO is prepared to discuss coordination of its monitoring program with 
any related work that might be done by other groups insofar as this is 
practical and desirable.

Vessel-based Visual Monitoring

    PSVOs will be based aboard the seismic source vessel and will watch 
for marine mammals near the vessel during daytime airgun operations and 
during any start-ups at night. PSVOs will also watch for marine mammals 
near the seismic vessel for at least 30 min prior to the start of 
airgun operations after an extended shut down. When feasible, PSVOs 
will also observe during daytime periods when the seismic system is not 
operating for comparison of sighting rates and behavior with vs. 
without airgun operations. Based on PSVO observations, the airguns will 
be powered down or shut down when marine mammals are observed within or 
about to enter a designated EZ. The EZ is a region in which a 
possibility exists of adverse effects on animal hearing or other 
physical effects.
    During seismic operations at the Shatsky Rise, five PSVOs will be 
based aboard the Langseth. L-DEO will appoint the PSVOs with NMFS' 
concurrence. At least one PSVO and when practical, two PSVOs will 
monitor marine mammals near the seismic vessel during ongoing daytime 
operations and nighttime start ups of the airguns. Use of two 
simultaneous observers will increase the effectiveness of detecting 
animals near the source vessel. PSVOs will be on duty in shifts of 
duration no longer than four hours. L-DEO will also instruct other crew 
to assist in detecting marine mammals and implementing mitigation 
requirements (if practical). Before the start of the seismic survey, L-
DEO will give the crew additional instruction regarding how to 
accomplish this task.
    The Langseth is a suitable platform for marine mammal and turtle 
observations. When stationed on the observation platform, the eye level 
will be approximately 21.5 m (70.5 ft) above sea level, and the 
observer will have a good view around the entire vessel. During 
daytime, the PSVOs will scan the area around the vessel systematically 
with reticle binoculars (e.g., 7 x 50 Fujinon), Big-eye binoculars (25 
x 150), and with the naked eye. During darkness, night vision devices 
(NVDs) will be available (ITT F500 Series Generation 3 binocular-image 
intensifier or equivalent), when required. Laser range-finding 
binoculars (Leica LRF 1200 laser rangefinder or equivalent) will be 
available to assist with distance estimation. Those are useful in 
training observers to estimate distances visually, but are generally 
not useful in measuring distances to animals directly; that is done 
primarily with the reticles in the binoculars.

Passive Acoustic Monitoring

    Passive Acoustic Monitoring (PAM) will complement the visual 
monitoring program, when practicable. Visual monitoring typically is 
not effective during periods of poor visibility or at night, and even 
with good visibility, is unable to detect marine mammals when they are 
below the surface or beyond visual range. L-DEO can use acoustical 
monitoring in addition to visual observations to improve detection, 
identification, and localization of cetaceans. The acoustic monitoring 
will serve to alert visual observers (if on duty) when vocalizing 
cetaceans are detected. It is only useful when marine mammals call, but 
it can be effective either by day or by night, and does not depend on 
good visibility. It will be monitored in real time so that the visual 
observers can be advised when

[[Page 28583]]

cetaceans are detected. When bearings (primary and mirror-image) to 
calling cetacean(s) are determined, the bearings will be relayed to the 
visual observer to help him/her sight the calling animal(s).
    The PAM system consists of hardware (i.e., hydrophones) and 
software. The ``wet end'' of the system consists of a towed four-
hydrophone array, two of which are monitored simultaneously; the active 
section of the array is approximately 30 m (98 ft) long. The array is 
attached to the vessel by a 250-m (820 ft) electromechanical lead-in 
cable and a 50-m (164 ft) long deck lead-in cable. However, not the 
entire length of lead-in cable is used; thus, the hydrophones are 
typically located 120 m (394 ft) behind the stern of the ship. The deck 
cable is connected from the array to a computer in the laboratory where 
signal conditioning and processing takes place. The digitized signal is 
then sent to the main laboratory, where the acoustic PSVO monitors the 
system. The hydrophone array is typically towed at depths less than 20 
m (66 ft).
    The towed hydrophones will ideally be monitored 24 hr/d while at 
the seismic survey area during airgun operations, and during most 
periods when the Langseth is underway while the airguns are not 
operating. One PSVO will monitor the acoustic detection system at any 
one time, by listening to the signals from two channels via headphones 
and/or speakers and watching the real-time spectrographic display for 
frequency ranges produced by cetaceans. PSVOs monitoring the acoustical 
data will be on shift for one to six hours at a time. Besides the 
visual PSVO, an additional PSVO with primary responsibility for PAM 
will also be aboard. All PSVOs are expected to rotate through the PAM 
position, although the most experienced with acoustics will be on PAM 
duty more frequently.
    When a vocalization is detected while visual observations are in 
progress, the acoustic PSVO will contact the visual PSVO immediately, 
to alert him/her to the presence of cetaceans (if they have not already 
been seen), and to allow a power down or shut down to be initiated, if 
required. The information regarding the call will be entered into a 
database. The data to be entered include an acoustic encounter 
identification number, whether it was linked with a visual sighting, 
date, time when first and last heard and whenever any additional 
information was recorded, position and water depth when first detected, 
bearing if determinable, species or species group (e.g., unidentified 
dolphin, sperm whale), types and nature of sounds heard (e.g., clicks, 
continuous, sporadic, whistles, creaks, burst pulses, strength of 
signal, etc.), and any other notable information. The acoustic 
detection can also be recorded for further analysis.

PSVO Data and Documentation

    PSVOs will record data to estimate the numbers of marine mammals 
exposed to various received sound levels and to document apparent 
disturbance reactions or lack thereof. Data will be used to estimate 
numbers of animals potentially `taken' by harassment (as defined in the 
MMPA). They will also provide information needed to order a power down 
or shut down of the airguns when a marine mammal is within or near the 
EZ.
    When a sighting is made, the following information about the 
sighting will be recorded:
    1. Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from seismic vessel, sighting cue, 
apparent reaction to the airguns or vessel (e.g., none, avoidance, 
approach, paralleling, etc.), and behavioral pace.
    2. Time, location, heading, speed, activity of the vessel, sea 
state, visibility, and sun glare.
    The data listed under (2) will also be recorded at the start and 
end of each observation watch, and during a watch whenever there is a 
change in one or more of the variables.
    All observations and power downs or shut downs will be recorded in 
a standardized format. Data will be entered into an electronic 
database. The accuracy of the data entry will be verified by 
computerized data validity checks as the data are entered and by 
subsequent manual checking of the database. These procedures will allow 
initial summaries of data to be prepared during and shortly after the 
field program, and will facilitate transfer of the data to statistical, 
graphical, and other programs for further processing and archiving.
    Results from the vessel-based observations will provide:
    1. The basis for real-time mitigation (airgun power down or shut 
down).
    2. Information needed to estimate the number of marine mammals 
potentially taken by harassment, which must be reported to NMFS.
    3. Data on the occurrence, distribution, and activities of marine 
mammals and turtles in the area where the seismic study is conducted.
    4. Information to compare the distance and distribution of marine 
mammals and turtles relative to the source vessel at times with and 
without seismic activity.
    5. Data on the behavior and movement patterns of marine mammals and 
turtles seen at times with and without seismic activity.
    L-DEO will submit a report to NMFS and NSF within 90 days after the 
end of the cruise. The report will describe the operations that were 
conducted and sightings of marine mammals and turtles near the 
operations. The report will provide full documentation of methods, 
results, and interpretation pertaining to all monitoring. The 90-day 
report will summarize the dates and locations of seismic operations, 
and all marine mammal sightings (dates, times, locations, activities, 
associated seismic survey activities). The report will also include 
estimates of the number and nature of exposures that could result in 
``takes'' of marine mammals by harassment or in other ways.
    L-DEO will report all injured or dead marine mammals (regardless of 
cause) to NMFS as soon as practicable. The report should include the 
species or description of the animal, the condition of the animal, 
location, time first found, observed behaviors (if alive) and photo or 
video, if available.

Estimated Take by Incidental Harassment

    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as:

    any act of pursuit, torment, or annoyance which (i) has the 
potential to injure a marine mammal or marine mammal stock in the 
wild [Level A harassment]; or (ii) has the potential to disturb a 
marine mammal or marine mammal stock in the wild by causing 
disruption of behavioral patterns, including, but not limited to, 
migration, breathing, nursing, breeding, feeding, or sheltering 
[Level B harassment].

    Only take by Level B harassment is anticipated and authorized as a 
result of the proposed marine geophysical survey at the Shatsky Rise. 
Acoustic stimuli (i.e., increased underwater sound) generated during 
the operation of the seismic airgun array, may have the potential to 
cause marine mammals in the survey area to be exposed to sounds at or 
greater than 160 decibels (dB) or cause temporary, short-term changes 
in behavior. There is no evidence that the planned activities could 
result in injury or mortality within the specified geographic area for 
which L-DEO seeks the IHA. The required mitigation and monitoring 
measures will minimize any potential risk for injury or mortality.
    The following sections describe L-DEO's methods to estimate take by

[[Page 28584]]

incidental harassment and present the applicant's estimates of the 
numbers of marine mammals that could be affected during the proposed 
geophysical survey. The estimates are based on a consideration of the 
number of marine mammals that could be disturbed appreciably by 
operations with the 36-airgun array to be used during approximately 
3,160 km of seismic surveys at the Shatsky Rise.
    L-DEO assumes that, during simultaneous operations of the airgun 
array and the other sources, any marine mammals close enough to be 
affected by the MBES and SBP would already be affected by the airguns. 
However, whether or not the airguns are operating simultaneously with 
the other sources, marine mammals are expected to exhibit no more than 
short-term and inconsequential responses to the MBES and SBP given 
their characteristics (e.g., narrow downward-directed beam) and other 
considerations described previously. Such reactions are not considered 
to constitute ``taking'' (NMFS, 2001). Therefore, L-DEO provides no 
additional allowance for animals that could be affected by sound 
sources other than airguns.
    Density data on 18 marine mammal species in the Shatsky Rise area 
are available from two sources using conventional line transect 
methods: Japanese sighting surveys conducted since the early 1980s, and 
fisheries observers in the high-seas driftnet fisheries during 1987-
1990 (see Table 3 in L-DEO's application). For the 16 other marine 
mammal species that could be encountered in the proposed survey area, 
data from the western North Pacific right whale are not available (see 
Table 3 in L-DEO's application Table 3). L-DEO is not aware of any 
density estimates for three of those species--Hubb's (Mesoplodon 
carlhubbsi), Stejneger's (Mesoplodon stejnegeri), and gingko-toothed 
beaked whales (Mesoplodon ginkgodens). For the remaining 13 species 
(see Table 3 in L-DEO's application), density estimates are available 
from other areas of the Pacific: 11 species from the offshore stratum 
of the 2002 Hawaiian Islands survey (Barlow, 2006) and two species from 
surveys of the California Current ecosystem off the U.S. west coast 
between 1991 and 2005 (Barlow and Forney, 2007). Those estimates are 
based on standard line-transect protocols developed by NMFS' Southwest 
Fisheries Science Center (SWFSC).
    Densities for 14 species are available from Japanese sighting 
surveys in the Shatsky Rise survey area. Miyashita (1993a) provided 
estimates for six dolphin species in this area that have been taken in 
the Japanese drive fisheries. The densities used here are Miyashita's 
(1993a) estimates for the `Eastern offshore' survey area (30-42[deg] N, 
145[deg]-180[deg] E). Kato and Miyashita (1998) provided estimates for 
sperm whale densities from Japanese sightings data during 1982 to 1996 
in the western North Pacific (20-50[deg] N, 130[deg]-180[deg] E), and 
Hakamada et al. (2004) provided density estimates for sei whales during 
August through September in the JARPN II sub-areas 8 and 9 (35-50[deg] 
N, 150-170[deg] E excluding waters in the Exclusive Economic Zone of 
Russia) during 2002 and 2003. L-DEO used density estimates during 1994 
through 2007 for minke whales at 35-40[deg] N, 157-170[deg] E from 
Hakamada et al. (2009), density estimates during 1998 through 2002 for 
Bryde's whales at 31-43[deg] N, 145-165[deg] E from Kitakado et al. 
(2008), and density estimates during 1994-2007 for blue, fin, humpback, 
and North Pacific right whales at 31-51[deg] N, 140-170[deg] E from 
Matsuoka et al. (2009).
    For four species (northern fur seal, Dall's porpoise, Pacific 
white-sided dolphin (Lagenorhynchus obliquidens), northern right-whale 
dolphin (Lissodelphis borealis)), estimates of densities in the Shatsky 
Rise area are available from sightings data collected by observers in 
the high-seas driftnet fisheries during 1987 through 1990 (Buckland et 
al., 1993). Those data were analyzed for 5[deg] x 5[deg] blocks, and 
the densities used here are from blocks for which available data 
overlap the proposed survey area. In general, those data represent the 
average annual density in the northern half of the Shatsky Rise survey 
area (35-40[deg] N).
    The densities mentioned above had been corrected by the original 
authors for detectability bias and, with the exception of Kitakado et 
al. (2008) and Hakamada et al. (2009), for availability bias. 
Detectability bias is associated with diminishing sightability with 
increasing lateral distance from the track line [f(0)]. Availability 
bias refers to the fact that there is less than a 100 percent 
probability of sighting an animal that is present along the survey 
track line, and it is measured by g(0).
    There is some uncertainty about the accuracy of the density data 
from the the Japanese Whale Research Program under Special Permit 
(JARPN/JARPN II). For example, densities in Miyashita (1993a) and 
Buckland et al. (1993) are from the 1980s and represent the best 
available information for the Shatsky Rise area at this time. To 
provide some allowance for these uncertainties, particularly 
underestimates of densities present and numbers of marine mammals 
potentially affected have been derived; L-DEO `s maximum estimates 
(precautionary estimates) are 1.5 times greater than the best 
estimates.
    The estimated numbers of individuals potentially exposed are based 
on the 160-dB re 1 [mu]Pa [middot] mrms criterion for all 
cetaceans (see Table 3 in this notice). It is assumed that marine 
mammals exposed to airgun sounds that strong might change their 
behavior sufficiently to be considered ``taken by harassment.''
    L-DEO estimates of exposures to various sound levels assume that 
the proposed surveys will be completed. As is typical during offshore 
ship surveys, inclement weather and equipment malfunctions are likely 
to cause delays and may limit the number of useful line-kilometers of 
seismic operations that can be undertaken. Furthermore, any marine 
mammal sightings within or near the designated exclusion zones will 
result in the power down or shut down of seismic operations as a 
mitigation measure. Thus, the following estimates of the numbers of 
marine mammals potentially exposed to sound levels of 160 re 1 [mu]Pa 
[middot] mrms are precautionary and probably overestimate 
the actual numbers of marine mammals that might be involved. These 
estimates also assume that there will be no weather, equipment, or 
mitigation delays, which is highly unlikely.
    Table 4 of L-DEO's application shows the best and maximum estimated 
number of exposures and the number of different individuals potentially 
exposed during the seismic survey if no animals moved away from the 
survey vessel. The requested take authorization, given in the far right 
column of Table 4 of L-DEO's application, is based on the maximum 
estimates rather than the best estimates of the numbers of individuals 
exposed, because of uncertainties associated with applying density data 
from one area to another.
    The number of different individuals that may be exposed to airgun 
sounds with received levels greater than or equal to 160 dB re 1 [mu]Pa 
[middot] mrms on one or more occasions was estimated by 
considering the total marine area that would be within the 160-dB 
radius around the operating airgun array on at least one occasion. The 
number of possible exposures (including repeated exposures of the same 
individuals) can be estimated by considering the total marine area that 
would be within the 160-dB radius around the operating airguns, 
including areas of overlap. In the proposed survey, the seismic lines 
are widely spaced in the proposed survey area, so an individual mammal 
would most likely not be exposed

[[Page 28585]]

numerous times during the survey; the area including overlap is only 
1.4 times the area excluding overlap. Moreover, it is unlikely that a 
particular animal would stay in the area during the entire survey. The 
number of different individuals potentially exposed to received levels 
greater than or equal to 160 re 1 [mu]Pa [middot] mrms was 
calculated by multiplying:
    (1) The expected species density, either ``mean'' (i.e., best 
estimate) or ``maximum'', times;
    (2) The anticipated minimum area to be ensonified to that level 
during airgun operations including overlap (exposures); or
    (3) The anticipated area to be ensonified to that level during 
airgun operations excluding overlap (individuals).
    The area expected to be ensonified was determined by entering the 
planned survey lines into a MapInfo Geographic Information System 
(GIS), using the GIS to identify the relevant areas by ``drawing'' the 
applicable 160-dB buffer (see Table 1) around each seismic line, and 
then calculating the total area within the buffers. Areas of overlap 
were included only once when estimating the number of individuals 
exposed.
    Applying the approach described above, approximately 20,831 square 
kilometers (km\2\) would be within the 160-dB isopleth on one or more 
occasions during the survey, whereas 22,614 km\2\ is the area 
ensonified to greater than or equal to 160 dB when overlap is included. 
Thus, an average individual marine mammal would be exposed only once 
during the survey. Because this approach does not allow for turnover in 
the mammal populations in the study area during the course of the 
survey, the actual number of individuals exposed could be 
underestimated. However, the approach assumes that no cetaceans will 
move away from or toward the trackline as the Langseth approaches in 
response to increasing sound levels prior to the time the levels reach 
160 dB, which will result in overestimates for those species known to 
avoid seismic vessels.
    Table 4 of L-DEO's application shows the best and maximum estimates 
of the number of exposures and the number of different individual 
cetaceans that potentially could be exposed to greater than or equal to 
160 dB re: 1 [mu]Pa during the seismic survey if no animals moved away 
from the survey vessel.
    The `best estimate' of the number of individual cetaceans that 
could be exposed to seismic sounds with received levels greater than or 
equal to 160 dB re: 1 [mu]Pa during the proposed survey is 13,299 (see 
Table 3 below this section). That total includes 155 baleen whales, 87 
of which are endangered: one North Pacific right whale or 0.6% of the 
regional population; 15 humpback whales (1.4%), 37 sei whales (0.4%), 
22 fin whales (0.1%), and 12 blue whales (0.4%). In addition, 22 sperm 
whales (also listed as endangered under the ESA) or less than 0.1% of 
the regional population could be exposed during the survey, and 198 
beaked whales including Cuvier's, Longman's, Baird's, Blainville's, and 
possibly ginkgo-toothed, Stejneger's, or Hubb's beaked whales. Most 
(96%) of the cetaceans potentially exposed are delphinids; short-beaked 
common, striped, pantropical spotted, and Pacific white-sided dolphins 
and melon-headed whales are estimated to be the most common species in 
the area, with best estimates of 6,444 (0.2% of the regional 
population), 2,480 (0.4%), 1,467 (0.3%), and 758 (0.1%) exposed to 
levels greater than or equal to 160 dB re: 1 [mu]Pa, respectively.

  Table 3--Estimates of the Possible Numbers of Marine Mammals Exposed to Different Sound Levels During L-DEO's
                       Proposed Seismic Survey at Shatsky Rise During July-September, 2010
----------------------------------------------------------------------------------------------------------------
                                                          Estimated number   Estimated number
                                                           of individuals     of individuals      Approximate
                                                          exposed to sound   exposed to sound      percent of
                        Species                           levels >=160 dB    levels >=160 dB        regional
                                                            re: 1 [mu]Pa       re: 1 [mu]Pa    population (best)
                                                               (Best)           (Maximum)
----------------------------------------------------------------------------------------------------------------
North Pacific right whale..............................                  1                  2               0.60
Humpback whale.........................................                 15                 22               1.43
Minke whale............................................                 57                 85               0.23
Bryde's whale..........................................                 11                 16               0.05
Sei whale..............................................                 37                 56               0.37
Fin whale..............................................                 22                 34               0.14
Blue whale.............................................                 12                 18               0.35
Sperm whale............................................                 22                 32               0.07
Pygmy sperm whale......................................                 66                100              <0.01
Dwarf sperm whale......................................                163                244              <0.01
Cuvier's beaked whale..................................                142                212               0.71
Baird's beaked whale...................................                 18                 27               N.A.
Longman's beaked whale.................................                  9                 14               N.A.
Blainville's beaked whale..............................                 27                 40               0.11
Mesoplodon spp.........................................                  2                  3               0.01
Rough-toothed dolphin..................................                 65                 97               0.04
Bottlenose dolphin.....................................                500                750               0.21
Pantropical spotted dolphin............................              1,467              2,200               0.33
Spinner dolphin........................................                 17                 26              <0.01
Striped dolphin........................................              2,480              3,721               0.44
Fraser's dolphin.......................................                 95                143               0.03
Short-beaked common dolphin............................              6,444              9,666               0.22
Pacific white-sided dolphin............................                758              1,137               0.08
Northern right whale dolphin...........................                  9                 13              <0.01
Risso's dolphin........................................                225                337               0.03
Melon-headed whale.....................................                 27                 41               0.06
Pygmy killer whale.....................................                  0                  0               0.00
False killer whale.....................................                 43                 64               0.27
Killer whale...........................................                  3                  5               0.04

[[Page 28586]]

 
Short-finned pilot whale...............................                104                156               0.20
Dall's porpoise........................................                457                686               0.03
Northern fur seal......................................                 37                 56              <0.01
----------------------------------------------------------------------------------------------------------------
Best and maximum estimates and regional population size estimates are based on Table 3 in L-DEO's application.
N.A. means not available.
Mesoplodon spp. could include ginkgo-toothed, Stejneger's, or Hubb's beaked whales; density (not available) is
  an arbitrary low value.

Negligible Impact and Small Numbers Analysis and 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 34 species of marine 
mammals could be potentially affected by Level B harassment over the 
course of the IHA. For each species, these numbers are small (each, 
less than two percent) relative to the population size.
    No injuries or mortalities are anticipated to occur as a result of 
the L-DEO's planned marine geophysical survey, and none are authorized. 
Only short-term behavioral disturbance is anticipated to occur due to 
the brief and sporadic duration of the survey activities. No mortality 
or injury is expected to occur, and due to the nature, degree, and 
context of behavioral harassment anticipated, the activity is not 
expected to impact rates of recruitment or survival.
    NMFS has preliminarily determined, provided that the aforementioned 
mitigation and monitoring measures are implemented, that the impact of 
conducting a marine geophysical survey at the Shatsky Rise in the 
northwest Pacific Ocean, July through September 2010, may result, at 
worst, in a temporary modification in behavior and/or low-level 
physiological effects (Level B harassment) of small numbers of certain 
species of marine mammals.
    While behavioral modifications, including temporarily vacating the 
area during the operation of the airgun(s), may be made by these 
species to avoid the resultant acoustic disturbance, the availability 
of alternate areas within these areas and the short and sporadic 
duration of the research activities, have led NMFS to preliminarily 
determine that this action will have a negligible impact on the species 
in the specified geographic region.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the mitigation and monitoring 
measures, NMFS preliminarily finds that L-DEO's planned research 
activities, will result in the incidental take of small numbers of 
marine mammals, by Level B harassment only, and that the total taking 
from the marine geophysical survey will have a negligible impact on the 
affected species or stocks.

Impact on Availability of Affected Species or Stock for Taking for 
Subsistence Uses

    There are no relevant subsistence uses of marine mammals implicated 
by this action.

Endangered Species Act

    Of the 34 species of marine mammals that may occur in the proposed 
survey area, six are listed as endangered under the ESA, including the 
north Pacific right, humpback, sei, fin, blue, and sperm whales. Under 
Section 7 of the ESA, NSF has initiated formal consultation with the 
NMFS, Office of Protected Resources, Endangered Species Division, on 
this proposed seismic survey. NMFS' Office of Protected Resources, 
Permits, Conservation and Education Division, has initiated formal 
consultation under Section 7 of the ESA with NMFS' Office of Protected 
Resources, Endangered Species Division, to obtain a Biological Opinion 
evaluating the effects of issuing the IHA on threatened and endangered 
marine mammals and, if appropriate, authorizing incidental take. NMFS 
will conclude formal Section 7 consultation prior to making a 
determination on whether or not to issue the IHA. If the IHA is issued, 
L-DEO will be required to comply with the Terms and Conditions of the 
Incidental Take Statement corresponding to NMFS' Biological Opinion 
issued to both NSF and NMFS' Office of Protected Resources.

National Environmental Policy Act (NEPA)

    L-DEO has prepared an EA, and an associated environmental report 
that analyzes the direct, indirect and cumulative environmental impacts 
of the proposed specified activities on marine mammals including those 
listed as threatened or endangered under the ESA. The associated 
report, prepared by LGL on behalf of NSF and L-DEO is entitled, 
``Environmental Assessment of a Marine Geophysical Survey by the R/V 
Marcus G. Langseth on the Shatsky Rise in the Northwest Pacific Ocean, 
July-September, 2010.'' Prior to making a final decision on the IHA 
application, NMFS will either prepare an independent EA, or, after 
review and evaluation of NSF's EA and associated Report, for 
consistency with the regulations published by the Council of 
Environmental Quality (CEQ) and NOAA Administrative Order 216-6, 
Environmental Review Procedures for Implementing the National 
Environmental Policy Act, adopt the NSF EA and make a decision of 
whether or not to issue a Finding of No Significant Impact (FONSI).

Preliminary Determinations

    NMFS has preliminarily determined that the impact of conducting the 
specific seismic survey activities described in this notice and the IHA 
request in the specific geographic region

[[Page 28587]]

within the Shatsky Rise area in the northwest Pacific Ocean may result, 
at worst, in a temporary modification in behavior (Level B harassment) 
of small numbers of marine mammals. Further, this activity is expected 
to result in a negligible impact on the affected species or stocks of 
marine mammals. The provision requiring that the activity not have an 
unmitigable impact on the availability of the affected species or stock 
of marine mammals for subsistence uses is not implicated for this 
proposed action.
    For reasons stated previously in this document, the specified 
activities associated with the proposed survey are not likely to cause 
TTS, PTS or other non-auditory injury, serious injury, or death to 
affected marine mammals because:
    (1) The likelihood that, given sufficient notice through relatively 
slow ship speed, marine mammals are expected to move away from a noise 
source that is annoying prior to its becoming potentially injurious;
    (2) The fact that cetaceans would have to be closer than 940 m (0.6 
mi) in deep water when the full array is in use at a 9 m (29.5 ft) tow 
depth from the vessel to be exposed to levels of sound believed to have 
even a minimal chance of causing PTS;
    (3) The fact that marine mammals would have to be closer than 3,850 
m (2.4 mi) in deep water when the full array is in use at a 9 m (29.5 
ft) tow depth from the vessel to be exposed to levels of sound (160 dB) 
believed to have even a minimal chance at causing TTS; and
    (4) The likelihood that marine mammal detection ability by trained 
observers is high at that short distance from the vessel.
    As a result, no take by injury, serious injury, or death is 
anticipated or authorized, and the potential for temporary or permanent 
hearing impairment is very low and will be avoided through the 
incorporation of the proposed monitoring and mitigation measures.
    While the number of marine mammals potentially incidentally 
harassed will depend on the distribution and abundance of marine 
mammals in the vicinity of the survey activity, the number of potential 
Level B incidental harassment takings (see Table 3 above this section) 
is estimated to be small, less than two percent of any of the estimated 
population sizes based on the data disclosed in Table 2 of this notice, 
and has been mitigated to the lowest level practicable through 
incorporation of the monitoring and mitigation measures mentioned 
previously in this document.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to L-DEO for conducting a marine geophysical survey at the 
Shatsky Rise area in the northwest Pacific Ocean, provided the 
previously mentioned mitigation, monitoring, and reporting requirements 
are incorporated. The duration of the IHA would not exceed one year 
from the date of its issuance.

Information Solicited

    NMFS requests interested persons to submit comments and information 
concerning this proposed project and NMFS' preliminary determination of 
issuing an IHA (see ADDRESSES). Concurrent with the publication of this 
notice in the Federal Register, NMFS is forwarding copies of this 
application to the Marine Mammal Commission and its Committee of 
Scientific Advisors.

    Dated: May 17, 2010.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2010-12296 Filed 5-20-10; 8:45 am]
BILLING CODE 3510-22-P