Takes of Marine Mammals Incidental to Specified Activities; Low-Energy Marine Geophysical Survey in the Central Pacific Ocean, May Through June, 2012, 19242-19262 [2012-7717]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 77, Number 62 (Friday, March 30, 2012)]
[Notices]
[Pages 19242-19262]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-7717]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XB048


Takes of Marine Mammals Incidental to Specified Activities; Low-
Energy Marine Geophysical Survey in the Central Pacific Ocean, May 
Through June, 2012

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 low-energy marine geophysical survey in the 
central Pacific Ocean, May through June, 2012. 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, 16 species of marine mammals during the specified 
activity.

DATES: Comments and information must be received no later than April 
28, 2012.

ADDRESSES: Comments on the application should be addressed to P. 
Michael Payne, Chief, Permits and Conservation Division, Office of 
Protected Resources, National Marine Fisheries Service, 1315 East-West 
Highway, Silver Spring, MD 20910. The mailbox address for providing 
email comments is ITP.Cody@noaa.gov. NMFS is not responsible for email 
comments sent to addresses other than the one provided here. Comments 
sent via email, 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 https://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.
    An electronic 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: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
    The following associated documents are also available at the same 
internet address: The U.S. National Science Foundation's (NSF) draft 
Environmental Assessment (EA) Pursuant To The National Environmental 
Policy Act (NEPA) and Executive Order 12114. The draft EA incorporates 
an ``Environmental Assessment of a Marine Geophysical Survey by the R/V 
Marcus G. Langseth in the central Pacific Ocean, May 2012,'' prepared 
by LGL Ltd., Environmental Research Associates (LGL), on behalf of NSF.
    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, 301-427-8401.

SUPPLEMENTARY INFORMATION: 

Background

    Section 101(a)(5)(D) of the Marine Mammal Protection Act of 1972, 
as amended (MMPA; 16 U.S.C. 1361 et seq.) directs the Secretary of 
Commerce (Secretary) 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, NMFS provides a notice of a proposed 
authorization to the public for review.
    Authorization for the 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 (where relevant). The authorization must 
set forth the permissible methods of taking, other means of effecting 
the least practicable adverse impact on the species or stock and its 
habitat, and requirements pertaining to the mitigation, monitoring and 
reporting of such 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's 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. NMFS must publish a notice in the Federal Register 
within 30 days of its determination to 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 December 12, 2012, from L-DEO for 
the taking by harassment, of marine mammals, incidental to conducting a 
low-energy marine seismic survey in the central Pacific Ocean. Upon 
receipt of additional information, NMFS

[[Page 19243]]

determined the application complete and adequate on February 28, 2012.
    L-DEO, with research funding from the NSF, plans to conduct the 
survey from May 1 through May 26, 2012 offshore the Line Islands in the 
central Pacific Ocean. L-DEO plans to use one source vessel, the R/V 
Marcus G. Langseth (Langseth), a seismic airgun array and a single 
hydrophone streamer to conduct the low-energy geophysical survey that 
will provide the data necessary to understand sedimentation patterns on 
the flanks of the Line Islands Ridge and to investigate how climate 
patterns have varied over time in the late Pleistocene period. In 
addition to the operations of the seismic airgun array and hydrophone 
streamer, L-DEO intends to operate a multibeam echosounder (MBES), a 
sub-bottom profiler (SBP), and an acoustic Doppler current profiler 
(ADCP) continuously throughout the survey except while on station for 
marine coring activities.
    Acoustic stimuli (i.e., increased underwater sound) generated 
during the operation of the seismic airgun array may have the potential 
to cause a short-term behavioral disturbance for marine mammals in the 
survey area. This is the principal means of marine mammal taking 
associated with these activities and L-DEO has requested an 
authorization to take 16 species of marine mammals by Level B 
harassment. Take is not expected to result from the use of the MBES, 
SBP, ADCP, or during marine coring operations for reasons discussed in 
this notice. Also, NMFS does not expect take to result from collision 
with the Langseth because it is a single vessel moving at relatively 
slow speeds (4.6 knots (kts); 8.5 kilometers (km) per hour (km/h); 5.3 
miles (mi) per hour (mph)) during seismic acquisition within the 
survey, for a relatively short period of time (approximately 6 days). 
It is likely that any marine mammal would be able to avoid the vessel.

Description of the Proposed Specified Activity

    L-DEO's proposed seismic survey in the central Pacific Ocean 
(partly in the Exclusive Economic Zone (EEZ) of the Republic of 
Kiribati and partly in the U.S. EEZ) is scheduled to commence on May 1, 
2012 and end on May 26, 2012. The Langseth would depart from Honolulu, 
Hawaii (HI) on May 1, 2012 and transit to the survey area in the 
central Pacific Ocean, approximately 1,800 km (1,118.4 mi) south of 
Hawaii. At the conclusion of the survey activities, the Langseth 
proposes to arrive in Honolulu, HI on May 26, 2012. 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 proposes to issue an authorization that is 
effective from May 1, 2012 to June 11, 2012.
    The research program will involve one source vessel, the Langseth. 
Geophysical survey activities will involve conducting seismic surveys 
at six sites in the Line Islands to determine coring locations (see 
Figure 1 in L-DEO's application). L-DEO will select coring sites from 
undisturbed sediments where there is potential for higher-than-normal 
sedimentation rates. The resulting cores will provide data necessary to 
understand how important climate patterns such as the El Ni[ntilde]o/La 
Ni[ntilde]a-Southern Oscillation and position of the Intertropical 
Convergence Zone have varied in the late Pleistocene. L-DEO plans to 
deploy a total of 15 piston cores, 30 gravity cores, and eight 
multicores during the cruise. The piston and gravity corers have 
maximum diameters of approximately 90 centimeters (cm) (35 inches (in)) 
and 45 cm (17 in), respectively. The multi-corer is an eight-legged, 
cone-shaped frame and a weighted inner frame that holds up to eight 
plastic core sampling tubes that are 80 cm (31.4 in) long and 
approximately 10 cm (3.9 in) in diameter. Considering these dimensions, 
the coring equipment has a very small footprint.
    For the seismic component of the research program, the Langseth 
will deploy an array of two, low-energy Sercel Generator Injector (GI) 
airguns as an energy source. The acoustic receiving system will consist 
of a 2-km-long (1.2 mi) hydrophone streamer. As the airguns are towed 
along the survey lines, the hydrophone streamer will receive the 
returning acoustic signals and transfer the data to the on-board 
processing system.
    The proposed study (e.g., equipment testing, startup, line changes, 
repeat coverage of any areas, and equipment recovery) will require 
approximately six days to complete approximately 1,853 square km 
(km\2\) (715.4 square mi (mi\2\)) of transect lines. The Langseth will 
conduct additional seismic operations in the survey area associated 
with turns, airgun testing, and repeat coverage of any areas where the 
initial data quality is sub-standard. L-DEO has added 25 percent of 
transect lines (463.2 km\2\; 178.8 mi\2\) for contingency operations 
for a total area of 2,316 km\2\ (894.2 mi\2\).
    L-DEO, the Langseth's operator, will conduct all planned seismic 
data acquisition activities, with on-board assistance by the scientists 
who have proposed the study. The Principal Investigators for this 
survey are Drs. J. Lynch-Stieglitz (Georgia Institute of Technology) 
and P. Polissar (L-DEO). The vessel will be self-contained, and the 
crew will live aboard the vessel for the entire cruise.

Description of the Specified Geographic Region

    L-DEO will conduct the proposed survey in international waters in 
the central Pacific Ocean. The study area will encompass an area in the 
Line Islands bounded by approximately 0.5-8 degrees ([deg]) South by 
156-162[deg] West (see Figure 1 in L-DEO's application). Water depths 
in the survey area range from approximately 1,100 to 5,000 m (0.68 to 
3.1 mi). The proposed seismic survey will be conducted in the EEZ of 
the Republic of Kiribati and partly in the U.S. EEZ. On behalf of NSF 
and L-DEO, the U.S. State Department will seek authorization for L-DEO 
to work in Kiribati's EEZ.

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 meters (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 pounds, is powered by two 3,550 horsepower (hp) Bergen 
BRG-6 diesel engines which drive two propellers. Each propeller has 
four blades and the shaft typically rotates at 600 or 750 revolutions 
per minute. The vessel also has an 800-hp bowthruster which is not used 
during seismic acquisition. The Langseth's operation speed during 
seismic acquisition will be approximately 4.6 kts (8.5 km/h; 5.3 mph) 
and the cruising speed of the vessel outside of seismic operations is 
typically 18.5 km/h (11.5 mph or 10 kts).
    The Langseth will tow a pair of 45- to 105-in\3\ Sercel GI airguns, 
as well as the 2-km-long hydrophone streamer, along predetermined lines 
(see Figure 1 in L-DEO's application). Given the relatively short 
streamer length behind the vessel, the turning rate of the vessel while 
the gear is deployed is much higher than the limit of five degrees per 
minute for a seismic vessel towing a streamer of more typical length (6 
km; 3.7 mi). Thus, the vessel is more maneuverable during operations.
    The vessel also has an observation tower from which protected 
species visual observers (PSVO) will watch for marine mammals before 
and during the proposed airgun operations. When

[[Page 19244]]

stationed on the observation platform, the PSVO's eye level will be 
approximately 21.5 m (71 ft) above sea level providing the PSVO an 
unobstructed view around the entire vessel.

Acoustic Source Specifications

Seismic Airguns

    The Langseth will deploy and tow an array consisting of a pair of 
45 to 105 in\3\ Sercel GI airguns with a total volume of approximately 
210 in\3\ at a tow depth of 3 m (9.8 ft). The dominant frequency 
components range from zero to 188 Hertz (Hz). The array configuration 
consists of the Langseth towing the two GI airguns 8 m (26.2 ft) apart, 
side-by-side, approximately 50 m (164 ft) behind the vessel. During the 
survey, each airgun will emit a pulse at approximately 12-second (s) 
intervals which corresponds to a shot interval of approximately 3.75 m 
(123 ft) at a speed of approximately 11 km/hr (5.9 kts; 6.8 mph).
    The generator chamber of each GI airgun, the one responsible for 
introducing the sound pulse into the ocean, is either 45 in\3\ or 105 
in\3\, depending on how it is configured. The injector chamber injects 
air into the previously-generated bubble to maintain its shape, and 
does not introduce more sound into the water. Depending on the 
configuration, the total effective volume will be 90 in\3\ or 210 
in\3\. As a precautionary measure, L-DEO assumes that they will use the 
larger volume.

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 the amount of sound 
transmitted in the near horizontal directions is reduced. However, the 
airgun array also emits sounds that travel horizontally toward non-
target areas.
    The nominal source levels of the airgun array used by L-DEO on the 
Langseth is 239 dB re: 1 [mu]Pa(p-p) and the rms value for a 
given airgun pulse is typically 16 dB re: 1 [mu]Pa lower than the peak-
to-peak value (Greene, 1997; McCauley et al., 1998, 2000a). However, 
the difference between rms and peak-to-peak values for a given pulse 
depends on the frequency content and duration of the pulse, among other 
factors.
    NSF's EA provides a detailed description of L-DEO's modeling for 
marine seismic source arrays for species mitigation as well as the 
characteristics of the airgun pulses in Appendix A. These are the 
nominal source levels applicable to downward propagation. The effective 
source levels for horizontal propagation are lower than those for 
downward propagation because of the directional nature of the sound 
from the airguns. NMFS refers the reviewers to the IHA application and 
EA documents for additional information.

Predicted Sound Levels for the Airguns

    L-DEO has modeled the received sound levels for the paired 105 
in\3\ GI airgun configuration, in relation to distance and direction 
from the airguns (see Figure 2 of L-DEO's application). The model does 
not allow for bottom interactions, and thus is most directly applicable 
to deep water.
    Tolstoy et al. (2004, 2009) reported results for propagation 
measurements of pulses from the Langseth's 6-, 10-, 12-, 20-, and 36-
airgun arrays and 2 GI airguns in shallow- (approximately 50 m (164 
ft)) and deep-water depths (approximately 1,600 m (5,249 ft)) in the 
Gulf of Mexico. However, Tolstoy et al. (2004) did not conduct 
measurements for the 2 GI airguns in deep water (greater than 1,000 m; 
3,280 ft). Results of the Gulf of Mexico calibration studies showed 
that radii around the airguns for various received levels varied with 
water depth and that sound propagation varied with array tow depth. L-
DEO used the results from the Gulf of Mexico study to determine the 
algorithm for its model that calculates the exclusion zones (EZ) for 
the two GI airguns. L-DEO uses these values to designate mitigation 
zones and to estimate take (described in greater detail in Section VII 
of L-DEO's application and Section IV of NSF's EA) for marine mammals.
    Comparison of the Tolstoy et al. (2009) calibration study with L-
DEO's model for the Langseth's 6-, 10-, 12-, 20-airgun arrays indicated 
that the model represents the actual received levels, within the first 
few kilometers, where the predicted EZs are located. However, the model 
for deep water (greater than 1,000 m; 3,280 ft) overestimated the 
received sound levels at a given distance but is still valid for 
defining exclusion zones at various tow depths (Tolstoy et al., 2004). 
Because the calibration study did not conduct measurements for the 2 GI 
airgun array in deep water, L-DEO proposed to use the EZs predicted by 
L-DEO's model for the proposed GI airgun operations in deep water as 
the EZs are likely conservative given the reported results for the 
other airgun arrays.
    Table 1 summarizes the predicted distances at which sound levels 
(160-,180-, and 190-dB re: 1 [mu]Pa) are expected to be received from 
the two GI airguns in deep water. To avoid the potential for injury, 
NMFS (1995, 2000) concluded that cetaceans should not be exposed to 
pulsed underwater noise at received levels exceeding 180 dB re: 1 
[mu]Pa. NMFS believes that to avoid the potential for permanent 
physiological damage (Level A harassment), cetaceans and pinnipeds 
should not be exposed to pulsed underwater noise at received levels 
exceeding 180 dB re: 1 [mu]Pa and 190 dB re: 1 [mu]Pa, respectively. 
The 180-dB and 190-dB levels are shutdown criteria applicable to 
cetaceans and pinnipeds, respectively as specified by NMFS (1995, 
2000). L-DEO used these levels were used to establish the EZs. If 
marine mammals are detected within or about to enter the appropriate 
EZ, L-DEO will shut-down the airguns immediately. NMFS also assumes 
that marine mammals exposed to levels exceeding 160 dB re: 1 [mu]Pa 
(rms) may experience Level B harassment.

[[Page 19245]]



  Table 1--Distances to Which Sound Levels >= 160, 180, 190 dB re: 1 [mu]Pa (rms) Could Be Received in Deep Water During the Proposed Seismic Survey in
                                                          the Central Pacific Ocean, May, 2012
                                                [Distances Are Based on Model Results Provided by L-DEO]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                            Predicted RMS radii distances (m)
            Source and volume                Tow depth  (m)            Water depth  (m)         --------------------------------------------------------
                                                                                                       160 dB             180 dB             190 dB
--------------------------------------------------------------------------------------------------------------------------------------------------------
Two GI airguns (105 in\3\)...............                  2  Deep (> 1,000 )..................                670                 70                 20
--------------------------------------------------------------------------------------------------------------------------------------------------------

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 (in water 
greater than 1,000 m; 3,280 ft) or four (less than 1,000 m; 3,280 ft) 
successive, fan-shaped transmissions, from two to 15 milliseconds (ms) 
in duration and each ensonifying a sector that extends 1[deg] fore-aft. 
Continuous wave pulses increase from two to 15 milliseconds (ms) long 
in water depths up to 2,600 m (8,530 ft). The MBES uses frequency-
modulated chirp pulses up to 100-ms long in water greater than 2,600 m 
(8,530 ft). 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 Chirp 3260 SBP 
concurrently during airgun and MBES operations to provide information 
about the sedimentary features and bottom topography. The SBP is 
capable of reaching depths of 10,000 m (6.2 mi). The dominant frequency 
component of the SBP is 3.5 kHz which is directed downward in a 
27[ordm] cone by a hull-mounted transducer on the vessel. The nominal 
power output is 10 kilowatts (kW), but the actual maximum radiated 
power is three kW or 222 dB re: 1 [mu]Pa. The ping duration is up to 64 
ms with a pulse interval of one second, but a common mode of operation 
is to broadcast five pulses at 1-s intervals followed by a 5-s pause.

Acoustic Doppler Current Profiler

    The Teledyne OS75 is an ADCP operating at a frequency of 75 kHz, 
producing a ping every 1.4 s. The system is a four-beam phased array 
with a beam angle of 30[deg]. Each beam has a width of 4[deg] and there 
is no overlap. Maximum output power is 1 kW with a maximum depth range 
of 700 m.
    NMFS expects that acoustic stimuli resulting from the proposed 
operation of the two GI airguns has the potential to harass marine 
mammals, incidental to the conduct of the proposed seismic survey. NMFS 
expects these disturbances to be temporary and result in a temporary 
modification in behavior and/or low-level physiological effects (Level 
B harassment only) of small numbers of certain species of marine 
mammals. 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 
(4.6 kts; 8.5 km/hr; 5.3 mph) during seismic acquisition. NMFS does not 
expect that the coring equipment, during the conduct of the seismic 
survey, has the potential to harass marine mammals because of the 
relatively small footprint and slow speed of the coring equipment.

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

    Twenty-six marine mammal species may occur in the proposed survey 
area, including 19 odontocetes (toothed cetaceans), 6 mysticetes 
(baleen whales) and one species of pinniped during May through June. 
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 blue 
(Balaenoptera musculus), fin (Balaenoptera physalus), humpback 
(Megaptera novaeangliae), sei (Balaenoptera borealis), and sperm 
(Physeter macrocephalus) whale and the Hawaiian monk seal (Monachus 
schauinslandi).
    Hawaiian monk seals have the potential to transit in the vicinity 
of the proposed seismic survey, although any occurrence would be rare 
as they are vagrants to the area. Based on available data, L-DEO does 
not expect to encounter Hawaiian monk seals within the proposed survey 
area and does not present analysis for these species. Accordingly, NMFS 
will not consider this pinniped species in greater detail and the 
proposed IHA will only address requested take authorizations for 
mysticetes and odontocetes.
    The species of marine mammals expected to be most common in the 
survey area (all odontocetes) include the pantropical spotted dolphin 
(Stenella attenuata), spinner dolphin (Stenella longirostris), and 
short-finned pilot whale (Globicephala macrorhynchus).
    The NMFS' Southwest Fisheries Science Center (SWFSC) conducted the 
only cetacean distribution studies in the survey area. The Pacific 
Island Cetacean and Ecosystem Assessment Survey (PICEAS), conducted 
during July through November 2005, estimated the abundance of cetaceans 
in the U.S. EEZs of Palmyra Atoll, Kingman Reef, Johnston Atoll, and 
surrounding waters south of Hawaii (Barlow et al., 2008). The Hawaiian 
Island Cetacean Ecosystem Assessment Survey (HICEAS), conducted in the 
EEZ of the Hawaiian Islands, approximately 1,400 km north of the survey 
area in 2002, estimated the abundance and distribution of cetaceans 
within the area using visual and acoustic methods (Barlow et al., 
2004).
    Several other studies of marine mammal distribution and abundance 
have occurred in the wider eastern tropical Pacific Ocean. The most 
extensive regional distribution and abundance data come primarily from 
multi-year vessel surveys conducted by NMFS' SWFSC. Researchers 
conducted the surveys during July to December in an area generally 
extending from 30[deg] North to 18[deg] South from the coastline to 
153[deg] West (Wade and Gerrodette, 1993; Ferguson and Barlow, 2001; 
Gerrodette et al., 2008; and Jackson et al., 2008). The western 
boundary of the survey area is ~350 km east of the proposed seismic 
survey area. Acoustic detections of cetaceans were also reported during 
summer/fall shipboard surveys in the eastern and central Pacific Ocean 
(Rankin et al. 2008).
    Table 2 presents information on the abundance, distribution, and 
conservation status of the marine mammals that may occur in the 
proposed survey area in May, 2012.

[[Page 19246]]



  Table 2--Habitat, Abundance, and Conservation Status of Marine Mammals That May Occur in or Near the Proposed
                                Seismic Survey Area in the Central Pacific Ocean
       [See text and Tables 2 and 3 in L-DEO's application and environmental analysis for further details]
----------------------------------------------------------------------------------------------------------------
                                  Occurrence in
            Species                survey area          Habitat        Abundance  in the    ESA 2     Density 3
                                    during May                               EPT 1
----------------------------------------------------------------------------------------------------------------
Mysticetes:
    Humpback whale............  Rare.............  Mainly nearshore    \4\ 20,800; 36,600  EN               0
                                                    waters and
                                                    banks.
    Bryde's whale.............  Common...........  Pelagic, coastal             \5\ 9,000  NL               0.58
    Sei whale.................  Rare.............  Mostly pelagic..            \6\ 10,422  EN               0
    Fin whale.................  Rare.............  Slope, pelagic..       \7\ 7260-12,620  EN               0
    Blue whale................  Rare.............  Pelagic, coastal     \8\ 13,620-18,680  EN               0.01
    Minke whale...............  Rare.............  Coastal.........             \9\ 1,400  NL               0
Odontocetes:
    Sperm whale...............  Common...........  Pelagic, steep             \10\ 26,053  EN               2.97
                                                    topography.
    Pygmy sperm whale.........  Uncommon.........  Deep waters off                   N.A.  NL               0.03
                                                    shelf.
    Dwarf sperm whale.........  Common...........  Deep, shelf,               \11\ 11,200  NL               7.65
                                                    slope.
    Blainville's beaked whale.  Uncommon.........  Pelagic.........            \9\ 20,000  NL               0.35
    Cuvier's beaked whale.....  Common...........  Slope, pelagic..              \12\ 291  NL               6.66
    Ginkgo-toothed beaked       Rare.............  Pelagic.........           \13\ 25,300  NL               0.35
     whale.
    Longman's beaked whale....  Uncommon.........  Pelagic.........           \13\ 25,300  NL               0.44
    Rough-toothed dolphin.....  Common...........  Mainly pelagic..               107,633  NL               1.24
    Bottlenose dolphin........  Common...........  Coastal, shelf,                335,834  NL               4.94
                                                    deep.
    Pantropical spotted         Common...........  Coastal and               \14\ 439,208  NL             120.4
     dolphin.                                       pelagic.
    Spinner dolphin...........  Common...........  Coastal and             \15\ 1,797,716  NL             183.5
                                                    pelagic.
    Striped dolphin...........  Common...........  Off continental                964,362  NL              16.45
                                                    shelf.
    Fraser's dolphin..........  Common...........  Pelagic.........           \9\ 289,300  NL               4.47
    Risso's dolphin...........  Common...........  Shelf, slope,                  110,457  NL               0.81
                                                    seamounts.
    Melon-headed whale........  Common...........  Pelagic.........            \9\ 45,400  NL               1.29
    Pygmy killer whale........  Uncommon.........  Pelagic, coastal            \9\ 38,900  NL               0
    False killer whale........  Common...........  Pelagic.........       \16\ 1,329; \9\  NL               0.10
                                                                                   39,800
    Killer whale..............  Rare.............  Widely                      \17\ 8,500  NL               0.15
                                                    distributed.
    Short-finned pilot whale..  Common...........  Pelagic, high-             \6\ 589,315  NL               5.07
                                                    relief.
----------------------------------------------------------------------------------------------------------------
N.A. Not available or not assessed.
\1\ Abundance from Gerrodette et al. (2008) unless otherwise indicated.
\2\ U.S. Endangered Species Act: EN = Endangered, T = Threatened, NL = Not listed.
\3\ Density (/1000 km\2\) estimates as listed in Table 3 of the application. Cetacean densities are
  based on NMFS SWFSC ETP ship transect surveys conducted in 1986-2006 from predictive modeling (Barlow et al.,
  2009; Read et al., 2009) or in 2002 from Barlow (2006). Densities are corrected for f(0) and g(0). Where no
  source is given, the species was not included in Read et al. (2009) or Barlow (2006).
\4\ North Pacific (Barlow et al. 2009a) and Southern Hemisphere (Reilly et al. 2008).
\5\ North Pacific (Wada 1976).
\6\ Gerrodette and Forcada (2002).
\7\ North Pacific (Tillman 1977).
\8\ Ohsumi and Wada (1974).
\9\ Wade and Gerrodette (1993).
\10\ Whitehead (2002).
\11\ Estimate mostly for K. sima but may also include K. breviceps (Wade and Gerrodette 1993).
\12\ Ferguson and Barlow (2003).
\13\ This estimate includes all species of the genus Mesoplodon (Wade and Gerrodette 1993).
\14\ For the western/southern offshore spotted dolphin.
\15\ For the whitebelly and the eastern spinner dolphin stocks (Gerrodette et al. 2008).
\16\ Palmyra stock (Barlow and Rankin 2007).
\17\ Ford (2009).

    NMFS refers the reader to Sections III and IV of L-DEO's 
application for detailed information regarding the abundance and 
distribution, population status, and life history and behavior of these 
species and their occurrence in the proposed project area. The 
application also presents how L-DEO calculated the estimated densities 
for the marine mammals in the proposed survey area. NMFS has reviewed 
these data and determined them to be the best available scientific 
information for the purposes of the proposed IHA.

Potential Effects on Marine Mammals

    Acoustic stimuli generated by the operation of the airguns, which 
introduce sound into the marine environment, may have the potential to 
cause Level B harassment of marine mammals in the proposed survey area. 
The effects of sounds from airgun operations might include one or more 
of the following: Tolerance, masking of natural sounds, behavioral 
disturbance, temporary or permanent 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. 
Based on the available data and studies described here, some behavioral 
disturbance is expected, but NMFS expects the disturbance to be 
localized and short-term.

Tolerance to Sound

    Studies on marine mammals' tolerance to sound in the natural 
environment are relatively rare. Richardson et al. (1995) defines 
tolerance as the occurrence of marine

[[Page 19247]]

mammals in areas where they are exposed to human activities or man-made 
noise. In many cases, tolerance develops by the animal habituating to 
the stimulus (i.e., the gradual waning of responses to a repeated or 
ongoing stimulus) (Richardson, et al., 1995; Thorpe, 1963), but because 
of ecological or physiological requirements, many marine animals may 
need to remain in areas where they are exposed to chronic stimuli 
(Richardson, et al., 1995).
    Numerous studies have shown that pulsed sounds from airguns are 
often readily detectable in the water at distances of many kilometers. 
Malme et al., (1985) studied the responses of humpback whales on their 
summer feeding grounds in southeast Alaska to seismic pulses from a 
airgun with a total volume of 100-in\3\. They noted that the whales did 
not exhibit persistent avoidance when exposed to the airgun and 
concluded that there was no clear evidence of avoidance, despite the 
possibility of subtle effects, at received levels up to 172 dB: re 1 
[mu]Pa.
    Weir (2008) observed marine mammal responses to seismic pulses from 
a 24-airgun array firing a total volume of either 5,085 in\3\ or 3,147 
in\3\ in Angolan waters between August 2004 and May 2005. She recorded 
a total of 207 sightings of humpback whales (n=66), sperm whales 
(n=124), and Atlantic spotted dolphins (n=17) and reported that there 
were no significant differences in encounter rates (sightings/hr) for 
humpback and sperm whales according to the airgun array's operational 
status (i.e., active versus silent).

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. 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 and Hernandez, 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. 
Refer to Appendix A(4) of L-DEO's environmental analysis for a more 
detailed discussion of masking effects on marine mammals.

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 (reviewed in 
Richardson, et al., 1995). 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 A (5.1) of L-DEO's environmental analysis, 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 migrating gray and bowhead whales, the 
observed changes in behavior appeared to be of little or no biological 
consequence to the animals (Richardson et al., 1995). 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 (Malme et al., 1986, 1988; Richardson et al., 1995). In 
many areas, seismic pulses from large arrays of airguns diminish to 
those levels at distances ranging from four 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 A(5) of NSF's 
EA have shown that some species of

[[Page 19248]]

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 array (2,678-in\3\) and to a single, 20-in\3\ airgun with source 
level of 227 dB re: 1 [micro]Pa (p-p). In the 1998 study, the 
researchers documented that avoidance reactions began at five to eight 
km (3.1 to 4.9 mi) from the array, and that those reactions kept most 
pods approximately three to four km (1.9 to 2.5 mi) from the operating 
seismic boat. In the 2000 study, McCauley et al. noted localized 
displacement during migration of four to five km (2.5 to 3.1 mi) by 
traveling pods and seven to 12 km (4.3 to 7.5 mi) 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 distance, the received level was 143 dB re: 1 [mu]Pa. 
The initial avoidance response generally occurred at distances of five 
to eight km (3.1 to 4.9 mi) from the airgun array and two km (1.2 mi) 
from the single airgun. However, some individual humpback whales, 
especially males, approached within distances of 100 to 400 m (328 to 
1,312 ft), where the maximum received level was 179 dB re: 1 [mu]Pa.
    Data collected by observers during several seismic surveys in the 
northwest Atlantic Ocean showed that sighting rates of humpback whales 
were significantly greater during non-seismic periods compared with 
periods when a full array was operating (Moulton and Holst, 2010). In 
addition, humpback whales were more likely to swim away and less likely 
to swim towards a vessel during seismic versus non-seismic periods 
(Moulton and Holst, 2010).
    Humpback whales on their summer feeding grounds in Frederick Sound 
and Stephens Passage, 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.
    Other 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). Although, 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 (12.4 to 18.6 mi) from a medium-sized airgun source at 
received sound levels of approximately 120 to 130 dB re: 1 [mu]Pa 
(Miller et al., 1999; Richardson et al., 1999; see Appendix A(5) of 
NSF's EA). 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 [micro]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 and Hernandez, 2009; 
Castellote et al., 2010). 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). Castellote et al. (2010) 
also observed localized avoidance by fin whales during seismic airgun 
events in the western Mediterranean Sea and adjacent Atlantic waters 
from 2006-2009. They reported that singing fin whales moved away from 
an operating airgun array for a time period that extended beyond the 
duration of the airgun activity.
    Ship-based monitoring studies of baleen whales (including blue, 
fin, sei, minke, and whales) in the northwest Atlantic found that 
overall, this group had lower sighting rates during seismic versus non-
seismic periods (Moulton and Holst, 2010). Baleen whales as a group 
were also seen significantly farther from the vessel during seismic 
compared with non-seismic periods, and they were more often seen to be 
swimming away from the operating seismic vessel (Moulton and Holst, 
2010). Blue and minke whales were initially sighted significantly 
farther from the vessel during seismic operations compared to non-
seismic periods; the same trend was observed for fin whales (Moulton 
and Holst, 2010). Minke whales were most often observed to be swimming 
away from the vessel when seismic operations were underway (Moulton and 
Holst, 2010).

[[Page 19249]]

    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. 
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; Allen and Angliss, 2011). 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; Allen and Agliss, 2011).
    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 earlier and 
(in more detail) in Appendix B of NSF's EA 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; Moulton and Holst, 2010).
    Seismic operators and protected species observers (PSOs) 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; Barkaszi et al., 2009; Moulton and 
Holst, 2010). 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, Barry et al., 2010; Moulton and Holst, 2010). 
In most cases, the avoidance radii for delphinids appear to be small, 
on the order of one km or 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. 
Summer aerial surveys conducted in the southeastern Beaufort Sea 
reported that sighting rates of beluga whales were significantly lower 
at distances of 10 to 20 km (6.2 to 12.4 mi) from an operating airgun 
array compared to distances of 20 to 30 km (12.4 to 18.6 mi). Further, 
PSOs on seismic boats in that area have rarely reported sighting beluga 
whales (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 (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 NSF's EA 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 (Ziphius cavirostris) 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. In 
fact, Moulton and Holst (2010) reported 15 sightings of beaked whales 
during seismic studies in the Northwest Atlantic; seven of those 
sightings were made at times when at least one airgun was operating. 
There was little evidence to indicate that beaked whale behavior was 
affected by airgun operations; sighting rates and distances were 
similar during seismic and non-seismic periods (Moulton and Holst, 
2010).
    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 Stranding and Mortality section 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. 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

[[Page 19250]]

porpoises (See Appendix A of NSF's EA).
    Pinnipeds--Pinnipeds are not likely to show a strong avoidance 
reaction to the airgun array. Visual monitoring from seismic vessels 
has shown only slight (if any) avoidance of airguns by pinnipeds, and 
only slight (if any) changes in behavior, see Appendix B(5) of NSF's 
EA. In the Beaufort Sea, some ringed seals avoided an area of 100 m 
(328 ft) to (at most) a few hundred meters around seismic vessels, but 
many seals remained within 100 to 200 m (328 to 656 ft) of the 
trackline as the operating airgun array passed by (e.g., Harris et al., 
2001; Moulton and Lawson, 2002; Miller et al., 2005). Ringed seal 
sightings averaged somewhat farther away from the seismic vessel when 
the airguns were operating than when they were not, but the difference 
was small (Moulton and Lawson, 2002). Similarly, in Puget Sound, 
sighting distances for harbor seals and California sea lions tended to 
be larger when airguns were operating (Calambokidis and Osmek, 1998). 
Previous telemetry work suggests that avoidance and other behavioral 
reactions may be stronger than evident to date from visual studies 
(Thompson et al., 1998).

Hearing Impairment and Other Physical Effects

    Exposure to high intensity sound for a sufficient duration may 
result in auditory effects such as a noise-induced threshold shift--an 
increase in the auditory threshold after exposure to noise (Finneran et 
al., 2005). Factors that influence the amount of threshold shift 
include the amplitude, duration, frequency content, temporal pattern, 
and energy distribution of noise exposure. The magnitude of hearing 
threshold shift normally decreases over time following cessation of the 
noise exposure. The amount of threshold shift just after exposure is 
called the initial threshold shift. If the threshold shift eventually 
returns to zero (i.e., the threshold returns to the pre-exposure 
value), it is called temporary threshold shift (TTS) (Southall et al., 
2007).
    Researchers have studied TTS 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.
    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). Table 1 (introduced 
earlier in this document) presents the distances from the Langseth's 
airguns at which the received energy level (per pulse, flat-weighted) 
would be expected to be greater than or equal to 180 dB re: 1 
[micro]Pa.
    To avoid the potential for injury, NMFS (1995, 2000) concluded that 
cetaceans should not be exposed to pulsed underwater noise at received 
levels exceeding 180 dB re: 1 [mu]Pa. NMFS believes that to avoid the 
potential for permanent physiological damage (Level A harassment), 
cetaceans should not be exposed to pulsed underwater noise at received 
levels exceeding 180 dB re: 1 [mu]Pa. The 180-dB level is a shutdown 
criterion applicable to cetaceans, as specified by NMFS (2000); these 
levels were used to establish the EZs. NMFS also assumes that cetaceans 
exposed to SPLs exceeding 160 dB re: 1 [mu]Pa may experience Level B 
harassment.
    Researchers have derived TTS information for odontocetes 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 the low abundance 
of baleen whales in the planned study area at the time of the survey, 
and the strong likelihood that baleen whales would avoid the 
approaching airguns (or vessel) before being exposed to levels high 
enough for TTS to occur.
    In pinnipeds, TTS thresholds associated with exposure to brief 
pulses (single or multiple) of underwater sound have not been measured. 
Initial evidence from more prolonged (nonpulse) exposures suggested 
that some pinnipeds (harbor seals in particular) incur TTS at somewhat 
lower received levels than do small odontocetes exposed for similar 
durations (Kastak et al., 1999, 2005; Ketten et al., 2001). The 
indirectly estimated TTS threshold for pulsed sounds would be 
approximately 181 to 186 dB re: 1 [micro]Pa (Southall et al., 2007), or 
a series of pulses for which the highest SEL values are a few dB lower. 
Corresponding values for California sea lions and northern elephant 
seals are likely to be higher (Kastak et al., 2005).
    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 dBs above that inducing mild TTS if the animal were 
exposed to strong sound pulses with rapid rise times--see

[[Page 19251]]

Appendix A(6) of NSF's EA. 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.

Stranding and Mortality

    When a live or dead marine mammal swims or floats onto shore and 
becomes ``beached'' or incapable of returning to sea, the event is 
termed a ``stranding'' (Geraci et al., 1999; Perrin and Geraci, 2002; 
Geraci and Lounsbury, 2005; NMFS, 2007). The legal definition for a 
stranding under the MMPA is that ``(A) a marine mammal is dead and is 
(i) on a beach or shore of the United States; or (ii) in waters under 
the jurisdiction of the United States (including any navigable waters); 
or (B) a marine mammal is alive and is (i) on a beach or shore of the 
United States and is unable to return to the water; (ii) on a beach or 
shore of the United States and, although able to return to the water, 
is in need of apparent medical attention; or (iii) in the waters under 
the jurisdiction of the United States (including any navigable waters), 
but is unable to return to its natural habitat under its own power or 
without assistance'' (16 U.S.C. 1421h).
    Marine mammals are known to strand for a variety of reasons, such 
as infectious agents, biotoxicosis, starvation, fishery interaction, 
ship strike, unusual oceanographic or weather events, sound exposure, 
or combinations of these stressors sustained concurrently or in series. 
However, the cause or causes of most strandings are unknown (Geraci et 
al., 1976; Eaton, 1979; Odell et al., 1980; Best, 1982). Numerous 
studies suggest that the physiology, behavior, habitat relationships, 
age, or condition of cetaceans may cause them to strand or might pre-
dispose them to strand when exposed to another phenomenon. These 
suggestions are consistent with the conclusions of numerous other 
studies that have demonstrated that combinations of dissimilar 
stressors commonly combine to kill an animal or dramatically reduce its 
fitness, even though one exposure without the other does not produce 
the same result (Chroussos, 2000; Creel, 2005; DeVries et al., 2003; 
Fair and Becker, 2000; Foley et al., 2001; Moberg, 2000; Relyea, 2005a; 
2005b, Romero, 2004; Sih et al., 2004).
    Strandings Associated with Military Active Sonar-Several sources 
have published lists of mass stranding events of cetaceans in an 
attempt to identify relationships between those stranding events and 
military active sonar (Hildebrand, 2004; IWC, 2005; Taylor et al., 
2004). For example, based on a review of stranding records between 1960 
and 1995, the International Whaling Commission (2005) identified ten 
mass stranding events and concluded that, out of eight stranding events 
reported from the mid-1980s to the summer of 2003, seven had been 
coincident with the use of mid-frequency active sonar and most involved 
beaked whales.
    Over the past 12 years, there have been five stranding events 
coincident with military MF active sonar use in which exposure to sonar 
is believed by NMFS and the Navy to have been a contributing factor to 
strandings: Greece (1996); the Bahamas (2000); Madeira (2000); Canary 
Islands (2002); and Spain (2006). NMFS refers the reader to Cox et al. 
(2006) for a summary of common features shared by the strandings events 
in Greece (1996), Bahamas (2000), Madeira (2000), and Canary Islands 
(2002); and Fernandez et al., (2005) for an additional summary of the 
Canary Islands 2002 stranding event.
    Potential for Stranding from Seismic Surveys--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). Appendix 
A(6) of NSF's EA 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. However, 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 in the Gulf of 
California, Mexico, when the L-DEO vessel R/V Maurice Ewing was 
operating a 20-airgun (8,490 in\3\) array in the general area. The link 
between the stranding

[[Page 19252]]

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 likelihood that any beaked whales nearby would avoid the 
approaching vessel before being exposed to high sound levels; and
    (2) 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.

Potential Effects of Other Acoustic Devices

Multibeam Echosounder
    L-DEO will operate the Kongsberg EM 122 MBES from the source vessel 
during the planned study. Sounds from the MBES are very short pulses, 
occurring for 2 to 15 ms once every 5 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 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 vessel (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.
    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 in this section.
    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 Ocean, 
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 this section). 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

[[Page 19253]]

the MBES rather drastically relative to that from naval sonar.
    Based upon the best available science, 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.
Sub-Bottom Profiler
    L-DEO will also operate an SBP from the source vessel during the 
proposed survey. 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 222 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 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. Based 
upon the best available science, NMFS believes that the brief exposure 
of marine mammals to signals from the SBP is not likely to result in 
the harassment of marine mammals.

Potential Effects of Vessel Movement and Collisions

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

Behavioral Responses to Vessel Movement

    There are limited data concerning marine mammal behavioral 
responses to vessel traffic and vessel noise, and a lack of consensus 
among scientists with respect to what these responses mean or whether 
they result in short-term or long-term adverse effects. In those cases 
where there is a busy shipping lane or where there is a large amount of 
vessel traffic, marine mammals may experience acoustic masking 
(Hildebrand, 2005) if they are present in the area (e.g., killer whales 
in Puget Sound; Foote et al., 2004; Holt et al., 2008). In cases where 
vessels actively approach marine mammals (e.g., whale watching or 
dolphin watching boats), scientists have documented that animals 
exhibit altered behavior such as increased swimming speed, erratic 
movement, and active avoidance behavior (Bursk, 1983; Acevedo, 1991; 
Baker and MacGibbon, 1991; Trites and Bain, 2000; Williams et al., 
2002; Constantine et al., 2003), reduced blow interval (Ritcher et al., 
2003), disruption of normal social behaviors (Lusseau, 2003; 2006), and 
the shift of behavioral activities which may increase energetic costs 
(Constantine et al., 2003; 2004)). A detailed review of marine mammal 
reactions to ships and boats is available in Richardson et al. (1995). 
For each of the marine mammal taxonomy groups, Richardson et al. (1995) 
provides the following assessment regarding reactions to vessel 
traffic:
    Toothed whales: ``In summary, toothed whales sometimes show no 
avoidance reaction to vessels, or even approach them. However, 
avoidance can occur, especially in response to vessels of types used to 
chase or hunt the animals. This may cause temporary displacement, but 
we know of no clear evidence that toothed whales have abandoned 
significant parts of their range because of vessel traffic.''
    Baleen whales: ``When baleen whales receive low-level sounds from 
distant or stationary vessels, the sounds often seem to be ignored. 
Some whales approach the sources of these sounds. When vessels approach 
whales slowly and non-aggressively, whales often exhibit slow and 
inconspicuous avoidance maneuvers. In response to strong or rapidly 
changing vessel noise, baleen whales often interrupt their normal 
behavior and swim rapidly away. Avoidance is especially strong when a 
boat heads directly toward the whale.''
    Behavioral responses to stimuli are complex and influenced to 
varying degrees by a number of factors, such as species, behavioral 
contexts, geographical regions, source characteristics (moving or 
stationary, speed, direction, etc.), prior experience of the animal and 
physical status of the animal. For example, studies have shown that 
beluga whales' reactions varied when exposed to vessel noise and 
traffic. In some cases, naive beluga whales exhibited rapid swimming 
from ice-breaking vessels up to 80 km (49.7 mi) away, and showed 
changes in surfacing, breathing, diving, and group composition in the 
Canadian high Arctic where vessel traffic is rare (Finley et al., 
1990). In other cases, beluga whales were more tolerant of vessels, but 
responded differentially to certain vessels and operating 
characteristics by reducing their calling rates (especially older 
animals) in the St. Lawrence River where vessel traffic is common 
(Blane and Jaakson, 1994). In Bristol Bay, Alaska, beluga whales 
continued to feed when surrounded by fishing vessels and resisted 
dispersal even when purposefully harassed (Fish and Vania, 1971).
    In reviewing more than 25 years of whale observation data, Watkins 
(1986) concluded that whale reactions to vessel traffic were ``modified 
by their previous experience and current activity: Habituation often 
occurred rapidly, attention to other stimuli or preoccupation with 
other activities sometimes overcame their interest or wariness of 
stimuli.'' Watkins noticed that over the years of exposure to ships in 
the Cape Cod area, minke whales changed from frequent positive interest 
(e.g., approaching vessels) to generally uninterested reactions; fin 
whales changed from mostly negative (e.g., avoidance) to uninterested 
reactions; right whales apparently continued the same variety of 
responses (negative, uninterested, and positive responses) with little 
change; and humpbacks dramatically changed from mixed responses that 
were often negative to reactions that were often strongly positive. 
Watkins (1986) summarized that ``whales near shore, even in regions 
with low vessel traffic, generally have become less wary of boats and 
their

[[Page 19254]]

noises, and they have appeared to be less easily disturbed than 
previously. In particular locations with intense shipping and repeated 
approaches by boats (such as the whale-watching areas of Stellwagen 
Bank), more and more whales had positive reactions to familiar vessels, 
and they also occasionally approached other boats and yachts in the 
same ways.''
    Although the radiated sound from the Langseth will be audible to 
marine mammals over a large distance, it is unlikely that animals will 
respond behaviorally (in a manner that NMFS would consider MMPA 
harassment) to low-level distant shipping noise as the animals in the 
area are likely to be habituated to such noises (Nowacek et al., 2004). 
In light of these facts, NMFS does not expect the Langseth's movements 
to result in Level B harassment.

Vessel Strike

    Ship strikes of cetaceans can cause major wounds, which may lead to 
the death of the animal. An animal at the surface could be struck 
directly by a vessel, a surfacing animal could hit the bottom of a 
vessel, or an animal just below the surface could be cut by a vessel's 
propeller. The severity of injuries typically depends on the size and 
speed of the vessel (Knowlton and Kraus, 2001; Laist et al., 2001; 
Vanderlaan and Taggart, 2007).
    The most vulnerable marine mammals are those that spend extended 
periods of time at the surface in order to restore oxygen levels within 
their tissues after deep dives (e.g., the sperm whale). In addition, 
some baleen whales, such as the North Atlantic right whale, seem 
generally unresponsive to vessel sound, making them more susceptible to 
vessel collisions (Nowacek et al., 2004). These species are primarily 
large, slow moving whales. Smaller marine mammals (e.g., bottlenose 
dolphin) move quickly through the water column and are often seen 
riding the bow wave of large ships. Marine mammal responses to vessels 
may include avoidance and changes in dive pattern (NRC, 2003).
    An examination of all known ship strikes from all shipping sources 
(civilian and military) indicates vessel speed is a principal factor in 
whether a vessel strike results in death (Knowlton and Kraus, 2001; 
Laist et al., 2001; Jensen and Silber, 2003; Vanderlaan and Taggart, 
2007). In assessing records in which vessel speed was known, Laist et 
al. (2001) found a direct relationship between the occurrence of a 
whale strike and the speed of the vessel involved in the collision. The 
authors concluded that most deaths occurred when a vessel was traveling 
in excess of 14.9 mph (24.1 km/hr;13 kts).
    L-DEO's proposed operation of one vessel for the proposed survey is 
relatively small in scale compared to the number of commercial ships 
transiting at higher speeds in the same areas on an annual basis. The 
probability of vessel and marine mammal interactions occurring during 
the proposed survey is unlikely due to the Langseth's slow operational 
speed, which is typically 4.6 kts (8.5 km/h; 5.3 mph). Outside of 
operations, the Langseth's cruising speed would be approximately 11.5 
mph (18.5 km/h; 10 kts) which is generally below the speed at which 
studies have noted reported increases of marine mammal injury or death 
(Laist et al., 2001).
    As a final point, the Langseth has a number of other advantages for 
avoiding ship strikes as compared to most commercial merchant vessels, 
including the following: The Langseth's bridge offers good visibility 
to visually monitor for marine mammal presence; PSVOs posted during 
operations scan the ocean for marine mammals and must report visual 
alerts of marine mammal presence to crew; and the PSVOs receive 
extensive training that covers the fundamentals of visual observing for 
marine mammals and information about marine mammals and their 
identification at sea.

Coring Activities

    None of the coring devices have an acoustic component. There would 
be no drilling or hammering associated with the coring devices as the 
coring devices would use gravity to penetrate the sediment. The 
Langseth crew would lower the coring devices slowly from the ship on a 
wire; the wire would be kept taught as a result of the weight of the 
corer equipment and gravity. Due to the anticipated taughtness of the 
wire, NMFS does not anticipate entanglement with the gear as it is 
deployed or retrieved from the vessel. Marine mammals would avoid the 
gear and avoid any potential strikes from the equipment.
    The potential effects to marine mammals described in this section 
of the document do not take into consideration the proposed monitoring 
and mitigation measures described later in this document (see the 
``Proposed Mitigation'' and ``Proposed Monitoring and Reporting'' 
sections) which, as noted are designed to effect the least practicable 
adverse impact on affected marine mammal species and stocks.

Anticipated Effects on Marine Mammal Habitat

    The proposed seismic survey is not anticipated to have any 
permanent impact on habitats used by the marine mammals in the proposed 
survey area, including the food sources they use (i.e., fish and 
invertebrates). Additionally, no physical damage to any habitat is 
anticipated as a result of conducting the proposed seismic survey. 
While it is anticipated that the specified activity may result in 
marine mammals avoiding certain areas due to temporary ensonification, 
this impact to habitat is temporary and reversible and was considered 
in further detail earlier in this document, as behavioral modification.
    The main impact associated with the proposed activity will be 
temporarily elevated noise levels and the associated direct effects on 
marine mammals, previously discussed in this notice. The next section 
discusses the potential impacts of anthropogenic sound sources on 
common marine mammal prey in the proposed survey area (i.e., fish and 
invertebrates).

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 NSF's EA). 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

[[Page 19255]]

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.
    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 NSF's EA). 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) exposed to five airgun shots were not significantly different 
from those of controls. 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) 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 C of NSF's EA).
    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.
    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

[[Page 19256]]

impinging sound field and not to the pressure component (Popper et al., 
2001; see also Appendix E of NSF's EA).
    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. 
Appendix D of L-DEO's EA provides a more detailed review of the 
literature on the effects of seismic survey sound on invertebrates.
    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.
    Andre et al. (2011) exposed four cephalopod species (Loligo 
vulgaris, Sepia officinalis, Octopus vulgaris, and Ilex coindetii) to 
two hours of continuous sound from 50 to 400 Hz at 157  5 
dB re: 1 [mu]Pa. They reported lesions to the sensory hair cells of the 
statocysts of the exposed animals that increased in severity with time, 
suggesting that cephalopods are particularly sensitive to low-frequency 
sound.
    The received SPL was reported as 157  5 dB re: 1 FPa, 
with peak levels at 175 dB re 1 FPa. As in the McCauley et al. (2003) 
paper on sensory hair cell damage in pink snapper as a result of 
exposure to seismic sound, the cephalopods were subjected to higher 
sound levels than they would be under natural conditions, and they were 
unable to swim away from the sound source.
    Physiological Effects--Physiological effects refer mainly to 
biochemical 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 would to 
implement the following mitigation measures for marine mammals:
    (1) Proposed EZs;
    (2) Speed or course alteration;
    (3) Shut-down procedures; and
    (4) Ramp-up procedures.
    Proposed Exclusion Zones--L-DEO uses safety radii to designate EZs 
and to estimate take for marine mammals. Table 1 (presented earlier in 
this document) shows the distances at which three sound levels (160-, 
180-, and 190-dB) are expected to be received from the two GI airguns. 
The 180 and 190 dB radii are shut-down criteria applicable to cetaceans 
and pinnipeds, respectively, as specified by NMFS (2000); these levels 
were used to

[[Page 19257]]

establish the EZs. If the PSO detects marine mammal(s) within or about 
to enter the appropriate EZ, L-DEO would shut down the airguns 
immediately.
    Speed or Course Alteration--If L-DEO detects a marine mammal 
outside the EZ and, based on its position and the relative motion, the 
marine mammal is likely to enter the EZ, L-DEO could change the 
vessel's speed and/or direct course. L-DEO would implement speed or 
course operation if operationally practicable, thus minimizing the 
effect on the planned science objectives. L-DEO would monitor the 
activities and movements of the marine mammal (relative to the seismic 
vessel) to determine if the animal is approaching the applicable EZ. If 
the animal appears likely to enter the EZ, L-DEO would implement 
further mitigative actions, i.e., either further course alterations or 
a shut-down of the seismic source. Typically, during seismic 
operations, the source vessel is unable to change speed or course and 
one or more alternative mitigation measures will need to be 
implemented.
    Shut-down Procedures--L-DEO will shut down the operating airgun(s) 
if a marine mammal is seen outside the EZ for the airgun(s), and if the 
vessel's speed and/or course cannot be changed to avoid having the 
animal enter the EZ, the seismic source will be shut-down before the 
animal is within the EZ. If a marine mammal is already within the EZ 
when first detected, the seismic source will be shut-down immediately.
    Following a shut-down, L-DEO will not resume airgun activity until 
the marine mammal has cleared the EZ. SIO will consider the animal to 
have cleared the EZ if:
     A PSO has visually observed the animal leave the EZ, or
     A PSO has not sighted the animal within the EZ for 15 min 
for species with shorter dive durations (i.e., small odontocetes or 
pinnipeds), or 30 min for species with longer dive durations (i.e., 
mysticetes and large odontocetes, including sperm, killer, and beaked 
whales).
    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 shut-down has exceeded that period. L-DEO proposes 
that, for the present cruise, this period would be approximately 15 
min. L-DEO has used similar periods (approximately 15 min) during 
previous L-DEO surveys.
    L-DEO will begin a ramp-up with a single GI airgun (105 in\3\) and 
will add the second GI airgun (105 in\3\) after five min. During ramp-
up, the PSOs will monitor the EZ, and if marine mammals are sighted, L-
DEO will implement a shut-down as though both GI airguns 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. If one airgun has operated, 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 
if they choose. A ramp-up from a shut-down may occur at night, but only 
where the EZ is small enough to be visible. SIO 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. NMFS's 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 NMFS's evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS or recommended by the public 
for previous low-energy seismic surveys, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable adverse impacts on marine mammal 
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.

Proposed Monitoring

    L-DEO proposes to sponsor marine mammal monitoring during the 
proposed 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

    L-DEO will position PSOs aboard the seismic source vessel to watch 
for marine mammals near the vessel during daytime airgun operations and 
during any ramp-ups at night. PSOs will also watch for marine mammals 
near the seismic vessel for at least 30 min prior to the ramp-up of 
airgun operations after an extended shut-down (i.e., greater than 
approximately 15 min for this proposed cruise). When feasible, PSOs 
will conduct observations during daytime periods when the seismic 
system is not operating for comparison of sighting rates and behavior 
with and without airgun operations and between acquisition periods. 
Based on PSO observations, the airguns will be 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 in the central Pacific Ocean, at least 
three PSOs will be based aboard the Langseth. L-DEO will appoint the 
PSOs with NMFS' concurrence. At least one PSO will monitor the EZs 
during seismic operations. Observations will take place during ongoing 
daytime operations and nighttime ramp-ups of the airguns. PSO(s) will 
be on duty in shifts of duration no longer than four hours. The vessel 
crew will also be instructed to assist in detecting marine mammals.

[[Page 19258]]

    The Langseth is a suitable platform for marine mammal 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.
    When the PSOs observe marine mammals within or about to enter the 
designated EZ, the Langseth will immediately shut-down the airguns if 
necessary. The PSOs will continue to maintain watch to determine when 
the animal(s) are outside the EZ by visual confirmation. Airgun 
operations will not resume until the animal is confirmed to have left 
the EZ, or if not observed after 15 min for species with shorter dive 
durations (small odontocetes and pinnipeds) or 30 min for species with 
longer dive durations (mysticetes and large odontocetes, including 
sperm, killer, and beaked whales).

PSO Data and Documentation

    PSOs 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 shut-down 
of the airguns when a marine mammal is within or near the EZ. 
Observations will also be made during daytime periods when the Langseth 
is underway without seismic operations (i.e., transits to, from, and 
through the study area) to collect baseline biological data.
    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, Beaufort 
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 as well as information regarding shut-downs of the 
seismic source, will be recorded in a standardized format. The data 
accuracy will be verified by the PSOs at sea, and preliminary reports 
will be prepared during the field program and summaries forwarded to 
the operating institution's shore facility and to NSF weekly or more 
frequently.
    Vessel-based observations by the PSO will provide the following 
information:
    1. The basis for real-time mitigation (airgun 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 in the area where the seismic study is conducted.
    4. Information to compare the distance and distribution of marine 
mammals relative to the source vessel at times with and without seismic 
activity.
    5. Data on the behavior and movement patterns of marine mammals 
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 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 potential 
``takes'' of marine mammals by harassment or in other ways. After the 
report is considered final, it will be publicly available on the NMFS 
and NSF Web sites.
    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as an injury (Level A harassment), serious injury or 
mortality (e.g., ship-strike, gear interaction, and/or entanglement), 
L-DEO shall immediately cease the specified activities and immediately 
report the incident to the Chief of the Permits and Conservation 
Division, Office of Protected Resources, NMFS, at 301-427-8401 and/or 
by email to Jolie.Harrison@noaa.gov and ITP.Cody@noaa.gov and the 
Pacific Islands Regional Stranding Coordinator at 808-944-2269 
(David.Schofield@noaa.gov). The report must include the following 
information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Name and type of vessel involved;
     Vessel's speed during and leading up to the incident;
     Description of the incident;
     Status of all sound source use in the 24 hours preceding 
the incident;
     Water depth;
     Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities will not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS will work with L-DEO to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. L-DEO may not resume their 
activities until notified by NMFS via letter, email, or telephone.
    In the event that L-DEO discovers an injured or dead marine mammal, 
and the lead PSVO determines that the cause of the injury or death is 
unknown and the death is relatively recent (i.e., in less than a 
moderate state of decomposition as described in the next paragraph), L-
DEO will immediately report the incident to the Chief of the Permits 
and Conservation Division, Office of Protected Resources, NMFS, at 301-
427-8401 and/or by email to Jolie.Harrison@noaa.gov and 
ITP.Cody@noaa.gov and the Pacific Islands Regional Stranding 
Coordinator at 808-944-2269 (David.Schofield@noaa.gov). The report must 
include the same information identified in the paragraph above. 
Activities may continue while NMFS reviews the circumstances of the 
incident. NMFS will work with L-DEO to determine whether modifications 
in the activities are appropriate.
    In the event that L-DEO discovers an injured or dead marine mammal, 
and

[[Page 19259]]

the lead PSVO determines that the injury or death is not associated 
with or related to the activities authorized in the IHA (e.g., 
previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), L-DEO will report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources, NMFS, at 301-427-8401 and/or by email to 
Jolie.Harrison@noaa.gov and ITP.Cody@noaa.gov and the Pacific Islands 
Regional Stranding Coordinator at 808-944-2269 
(David.Schofield@noaa.gov), within 24 hours of the discovery. L-DEO 
will provide photographs or video footage (if available) or other 
documentation of the stranded animal sighting to NMFS. Activities may 
continue while NMFS reviews the circumstances of the incident.

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 proposed to be 
authorized as a result of the proposed marine seismic survey in the 
central Pacific Ocean. 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 dB or cause temporary, short-
term changes in behavior. There is no evidence that the planned 
activities could result in injury, serious 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, serious injury, or mortality.
    The following sections describe L-DEO's methods to estimate take by 
incidental harassment and present the applicant's estimates of the 
numbers of marine mammals that could be affected during the proposed 
seismic program. The estimates are based on a consideration of the 
number of marine mammals that could be disturbed appreciably by 
operations with the two GI airgun array to be used during approximately 
2,316 km\2\ (894 mi\2\) (includes primary and secondary lines and an 
additional 25 percent contingency) of survey lines in the central 
Pacific Ocean.
    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, SBP, and ADCP 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, SBP, and ADCP 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 the marine mammal species in the proposed survey 
area are available from two sources: (1) the NMFS Southwest Fishery 
Science Center (SWFSC) habitat model that estimates eastern tropical 
Pacific Ocean (ETP) cetacean densities on a finer spatial scale than 
traditional line-transect analyses by using a continuous function of 
habitat variables, e.g., sea surface temperature, depth, distance from 
shore, and prey density (Barlow et al., 2009b); and (2) densities from 
the offshore stratum of the surveys of Hawaiian waters conducted in 
August-November 2002 (Barlow, 2006).
    For the ETP ship transect surveys, the SWFSC based the models on 
data from 12 SWFSC ship-based cetacean and ecosystem assessment surveys 
conducted during July-December 1986-2006, extending east of the 
proposed survey area.
    The models have been incorporated into a web-based Geographic 
Information System (GIS) developed by Duke University's Department of 
Defense Strategic Environmental Research and Development Program 
(SERDP) team in close collaboration with the SWFSC SERDP team (Read et 
al., 2009). For the cetacean species in the model, L-DEO used the GIS 
to obtain mean densities in the proposed survey area, i.e., in a 
rectangle bounded by 150 and 156[deg] W and 5 and 10[deg] N. For 
species not included in the model, we used densities from the offshore 
stratum of the surveys of Hawaiian waters conducted in August-November 
2002 (Barlow 2006).
    Table 3 in L-DEO's application shows estimated densities for each 
cetacean species that could occur in the proposed survey area. They 
have corrected the densities for both trackline detection probability 
and availability bias by the authors. Trackline detection probability 
bias is associated with diminishing sightability with increasing 
lateral distance from the trackline [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 trackline [g(0)].
    Because survey effort within the proposed survey area is limited, 
and densities for some species are from offshore Hawaiian waters, there 
is some uncertainty about the representativeness of the data and the 
assumptions used in the calculations below. However, the approach used 
here is believed to be the best available approach.
    L-DEO's 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. L-DEO has included an 
additional 25 percent of line transects to account for mission 
uncertainty and to accommodate turns and lines that may need to be 
repeated. 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 dB re: 1 [mu]Pa 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.
    L-DEO estimated 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 on one or more occasions by considering the total 
marine area that would be within the 160-dB radius around the operating 
airgun array on at least one occasion and the expected density of 
marine mammals. 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 parallel and in close proximity; thus individuals 
could be exposed on two or more occasions. The area including overlap 
is 1.01 times

[[Page 19260]]

the area excluding overlap. Thus a marine mammal that stayed in the 
survey area during the entire survey could be exposed once, on average. 
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 was calculated by 
multiplying:
    (1) The expected species density, times
    (2) The anticipated area to be ensonified to that level during 
airgun operations excluding overlap, which is approximately 1,853 km\2\ 
(715.4 mi\2\).
    The area expected to be ensonified was determined by entering the 
planned survey lines into a MapInfo 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 this approach, 
approximately 2,316 km\2\ (894.2 mi\2\) would be within the 160-dB 
isopleth on one or more occasions 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 3 in this notice shows estimates of the number of 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 requested take authorization is shown in 
the far right column of Table 3. For endangered species, the requested 
take authorization reflects the mean group size in the ETP (Jackson et 
al., 2008) for the particular species in cases where the calculated 
number of individuals exposed was between 0.05 and the mean group size 
(i.e., for the sperm whale). For non-listed species, the requested take 
authorization reflects the mean group size in the SWFSC survey area 
(Barlow et al., 2008) for the particular species in cases where the 
calculated number of individuals exposed was between one and the mean 
group size.
    The total 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 828 (see Table 3 
in this notice; Table 4 in L-DEO's application). That total includes: 
four Bryde's whales or 0.01 percent of the regional population; and 7 
sperm whales (also listed as endangered) or 0.03 percent of the 
regional population could be exposed during the survey. L-DEO did not 
estimate take of endangered humpback, sei, blue, or fin whales or 
Hawaiian monk seals because of the low likelihood of encountering these 
species during the cruise. In addition, 18 beaked whales (16 Cuvier's, 
one Longman's, and one Mesoplodon spp.) could be exposed during the 
survey (see Table 3 in this notice; Table 4 in L-DEO's application). 
Most (94.7 percent) of the cetaceans that could be potentially exposed 
are delphinids (e.g., spinner, pantropical spotted, and striped 
dolphins are estimated to be the most common species in the area) with 
maximum estimates ranging from four to 425 species exposed to levels 
greater than or equal to 160 dB re: 1 [mu]Pa.

  Table 3--Estimates of the Possible Numbers of Marine Mammals Exposed to Different Sound Levels During L-DEO's
                      Proposed Seismic Survey in the Central Pacific Ocean During May, 2012
----------------------------------------------------------------------------------------------------------------
                                                          Estimated number
                                                           of individuals      Approximate
                        Species                          exposed to  sound      percent of       Requested take
                                                          levels >= 160 dB       regional        authorization
                                                          re: 1 [mu]Pa \1\    population \2\
----------------------------------------------------------------------------------------------------------------
Bryde's whale..........................................                  1               0.01              \4\ 4
Blue whale.............................................                  0             < 0.01                  0
Sperm whale............................................                  7               0.03              \4\ 8
Dwarf sperm whale......................................                 18               0.16                 18
Cuvier's beaked whale..................................                 16               0.08                 16
Longman's beaked whale.................................                  1               0.36             \4\ 14
Mesoplodon spp.\3\.....................................                  1              <0.01              \4\ 4
Rough-toothed dolphin..................................                  3              <0.01             \4\ 13
Bottlenose dolphin.....................................                 11              <0.01             \4\ 12
Pantropical spotted dolphin............................                279               0.06                279
Spinner dolphin........................................                425               0.02                425
Striped dolphin........................................                 38              <0.01             \4\ 46
Fraser's dolphin.......................................                 11              <0.01            \4\ 182
Risso's dolphin........................................                  2              <0.01             \4\ 14
Melon-headed whale.....................................                  3               0.01            \4\ 101
False killer whale.....................................                  0              <0.01              \4\ 9
Short-finned pilot whale...............................                 12              <0.01             \4\ 24
----------------------------------------------------------------------------------------------------------------
\1\ Estimates are based on densities from Table 3 and an ensonified area (including 25 percent contingency).
\2\ Regional population size estimates are from Table 2.
\3\ Includes ginkgo-toothed and/or Blainville's beaked whales.
\4\ Requested take authorization increased to mean group size (see text on page 40).

Encouraging and Coordinating Research

    L-DEO and NSF will coordinate the planned marine mammal monitoring 
program associated with the seismic survey in the central Pacific Ocean 
with any parties that may have or express an interest in the proposed 
seismic survey area. L-DEO and NSF have coordinated, and will continue 
to coordinate, with other applicable Federal agencies as required, and 
will comply with their requirements. Pursuant to IHA requirements, L-
DEO will submit a

[[Page 19261]]

monitoring report to NMFS 90 days after the proposed survey.

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 evaluated factors such as:
    (1) The number of anticipated injuries, serious injuries, or 
mortalities;
    (2) The number, nature, and intensity, and duration of Level B 
harassment (all relatively limited);
    (3) The context in which the takes occur (i.e., impacts to areas of 
significance, impacts to local populations, and cumulative impacts when 
taking into account successive/contemporaneous actions when added to 
baseline data);
    (4) The status of stock or species of marine mammals (i.e., 
depleted, not depleted, decreasing, increasing, stable, and impact 
relative to the size of the population);
    (5) Impacts on habitat affecting rates of recruitment/survival; and
    (6) The effectiveness of monitoring and mitigation measures (i.e., 
the manner and degree in which the measure is likely to reduce adverse 
impacts to marine mammals, the likely effectiveness of the measures, 
and the practicability of implementation).
    For reasons stated previously in this document, the specified 
activities associated with the marine seismic survey are not likely to 
cause PTS, or other non-auditory injury, serious injury, or death 
because:
    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;
    (1) The potential for temporary or permanent hearing impairment is 
relatively low and would likely be avoided through the incorporation of 
the required monitoring and mitigation measures (described above this 
section);
    (2) The fact that cetaceans would have to be closer than 70 m 
(229.7 ft) in deep water when the two GI airgun array is in 3 m (9.8 
ft) tow depth from the vessel to be exposed to levels of sound believed 
to have even a minimal chance of causing PTS; and
    (3) The likelihood that marine mammal detection ability by trained 
PSOs is high at close proximity to the vessel.
    No injuries, serious injuries, or mortalities are anticipated to 
occur as a result of L-DEO's planned marine seismic survey, and none 
are proposed to be authorized by NMFS. Only short-term, behavioral 
disturbance is anticipated to occur due to the brief and sporadic 
duration of the survey activities. Table 3 in this document outlines 
the number of Level B harassment takes that are anticipated as a result 
of the activities. Due to the nature, degree, and context of Level B 
(behavioral) harassment anticipated and described (see Potential 
Effects on Marine Mammals section above) in this notice, the proposed 
activity is not expected to impact rates of recruitment or survival for 
any affected species or stock.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (i.e., 24 hr cycle). 
Behavioral reactions to noise exposure (such as disruption of critical 
life functions, displacement, or avoidance of important habitat) are 
more likely to be significant if they last more than one diel cycle or 
recur on subsequent days (Southall et al., 2007). While seismic 
operations are anticipated to occur on consecutive days, the entire 
duration of the survey is not expected to last more than six days and 
the Langseth will be continuously moving along planned tracklines. 
Therefore, the seismic survey will be increasing sound levels in the 
marine environment surrounding the vessel for several weeks in the 
study area. Of the 26 marine mammal species under NMFS' jurisdiction 
likely to occur in the survey area, six are listed as endangered under 
the ESA: The humpback, sei, fin, blue, and sperm whale and the Hawaiian 
monk seal. These species are also considered depleted under the MMPA. 
However, no take of endangered humpback, sei, blue, or fin whales or 
Hawaiian monk seals was requested because of the low likelihood of 
encountering these species during the cruise. As mentioned previously, 
the survey would not occur in any areas designated as critical habitat 
for ESA-listed species and would not adversely impact marine mammal 
habitat. There is generally insufficient data to determine population 
trends for the other depleted species in the study area. To protect 
these animals (and other marine mammals in the study area), L-DEO must 
cease or reduce airgun operations if animals enter designated zones. No 
injury, serious injury, or mortality is expected to occur and due to 
the nature, degree, and context of the Level B harassment anticipated, 
the activity is not expected to impact rates of recruitment or 
survival.
    As mentioned previously, NMFS estimates that 16 species of marine 
mammals under its jurisdiction could be potentially affected by Level B 
harassment over the course of the proposed IHA. For each species, these 
numbers are small (each less than one percent) relative to the regional 
population size. The population estimates for the marine mammal species 
that may be taken by harassment were provided in Table 2 of this 
document.
    NMFS' practice has been to apply the 160 dB re 1 [micro]Pa (rms) 
received level threshold for underwater impulse sound levels to 
determine whether take by Level B harassment occurs. Southall et al. 
(2007) provide a severity scale for ranking observed behavioral 
responses of both free-ranging marine mammals and laboratory subjects 
to various types of anthropogenic sound (see Table 4 in Southall et al. 
[2007]).
    NMFS has preliminarily determined, provided that the aforementioned 
mitigation and monitoring measures are implemented, that the impact of 
conducting a marine seismic survey in the central Pacific Ocean, May, 
2012, 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. See Table 3 (above) for 
the requested authorized take numbers of cetaceans.
    While behavioral modifications, including temporarily vacating the 
area during the operation of the airgun(s), may be maCde by these 
species to avoid the resultant acoustic disturbance, the availability 
of alternate areas within this region 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 seismic survey will have a negligible impact on the 
affected species or stocks of marine mammals; and that impacts to 
affected species or stocks of marine mammals

[[Page 19262]]

have been mitigated to the lowest level practicable.

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

    Section 101(a)(5)(D) also requires NMFS to determine that the 
authorization will not have an unmitigable adverse effect on the 
availability of marine mammal species or stocks for subsistence use. 
There are no relevant subsistence uses of marine mammals in the study 
area (offshore waters of the Line Islands in the central Pacific Ocean) 
that implicate MMPA section 101(a)(5)(D).

Endangered Species Act

    Of the species of marine mammals that may occur in the proposed 
survey area, several are listed as endangered under the ESA, including 
the humpback, sei, fin, blue, and sperm whale and Hawaiian monk seal. 
L-DEO did not request take of endangered humpback, sei, blue, or fin 
whales or Hawaiian monk seals because of the low likelihood of 
encountering these species during the cruise. As mentioned previously, 
the survey would not occur in any areas designated as critical habitat 
for ESA-listed species and would not adversely impact marine mammal 
habitat.
    Under section 7 of the ESA, NSF has initiated formal consultation 
with the NMFS', Office of Protected Resources, Endangered Species Act 
Interagency Cooperation Division on this proposed seismic survey. NMFS' 
Office of Protected Resources, Permits and Conservation Division has 
initiated formal consultation under section 7 of the ESA with NMFS' 
Office of Protected Resources, Endangered Species Act Interagency 
Cooperation 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, NSF and L-DEO, 
in addition to the mitigation and monitoring requirements included in 
the IHA, 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)

    With its complete application, NSF and L-DEO provided NMFS a 
``Environmental Assessment and Finding of No Significant Impact (FONSI) 
Determination Pursuant to the National Environmental Policy Act, (NEPA: 
42 U.S.C. 4321 et seq.) and Executive Order 12114 for a ``Marine 
Geophysical Survey by the R/V Marcus G. Langseth in the Central Pacific 
Ocean May, 2012,'' which incorporates an ``Environmental Assessment of 
a Marine Geophysical Survey by the R/V Marcus G. Langseth in the 
central Pacific Ocean, May, 2012,'' prepared by LGL on behalf of NSF 
and L-DEO. The EA analyzes the direct, indirect, and cumulative 
environmental impacts of the specified activities on marine mammals 
including those listed as threatened or endangered under the ESA. NMFS 
conducted an independent review and evaluation of the document for 
sufficiency and compliance with the Council of Environmental Quality 
and NOAA Administrative Order 216-6 Sec.  5.09(d), Environmental Review 
Procedures for Implementing the National Environmental Policy Act, and 
determined that issuance of the IHA is not likely to result in 
significant impacts on the human environment. Consequently, NMFS plans 
to adopt NSF's EA and prepared a FONSI for the issuance of the IHA. An 
Environmental Impact Statement is not required and will not be prepared 
for the action.

Proposed Authorization

    NMFS proposes to issue an IHA to L-DEO for conducting a marine 
geophysical survey in the central 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: March 26, 2012.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2012-7717 Filed 3-29-12; 8:45 am]
BILLING CODE 3510-22-P