Takes of Marine Mammals Incidental to Specified Activities; Marine Geophysical Survey in the Northeast Atlantic Ocean, June to July, 2013, 17359-17383 [2013-06504]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 78, Number 55 (Thursday, March 21, 2013)]
[Notices]
[Pages 17359-17383]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-06504]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XC461


Takes of Marine Mammals Incidental to Specified Activities; 
Marine Geophysical Survey in the Northeast Atlantic Ocean, June to 
July, 2013

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 the Lamont-Doherty Earth 
Observatory of Columbia University (L-DEO) for an Incidental Harassment 
Authorization (IHA) to take marine mammals, by harassment, incidental 
to conducting a marine geophysical (seismic) survey in the northeast 
Atlantic Ocean, June to July, 2013. 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, 20 species of marine mammals during the specified activity.

DATES: Comments and information must be received no later than April 
22, 2013.

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.Goldstein@noaa.gov. Please include 0648-XC461 in 
the subject line. 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.
    A copy of the application containing a list of the references used 
in this document may be obtained by writing to the above address, 
telephoning the

[[Page 17360]]

contact listed here (see FOR FURTHER INFORMATION CONTACT) or visiting 
the Internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
    The National Science Foundation (NSF), which owns the R/V Marcus G. 
Langseth, has prepared a draft ``Environmental Analysis of a Marine 
Geophysical Survey by the R/V Marcus G. Langseth for the Northeast 
Atlantic Ocean, June-July 2013,'' prepared by LGL Ltd., Environmental 
Research Associates, on behalf of NSF and L-DEO, which is also 
available at the same Internet address. Documents cited in this notice 
may be viewed, by appointment, during regular business hours, at the 
aforementioned address.

FOR FURTHER INFORMATION CONTACT: Howard Goldstein or Jolie Harrison, 
Office of Protected Resources, NMFS, 301-427-8401.

SUPPLEMENTARY INFORMATION: 

Background

    Section 101(a)(5)(D) of the MMPA, as amended (16 U.S.C. 1371 
(a)(5)(D)), 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, a notice 
of a proposed authorization is provided 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 ``[hellip]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.
    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

    On January 8, 2013, NMFS received an application from the L-DEO 
requesting that NMFS issue an IHA for the take, by Level B harassment 
only, of small numbers of marine mammals incidental to conducting a 
marine seismic survey on the high seas (i.e., International Waters) and 
within the Exclusive Economic Zone of Spain during June to July, 2013. 
L-DEO plan to use one source vessel, the R/V Marcus G. Langseth 
(Langseth) and a seismic airgun array to collect seismic data as part 
of the proposed seismic survey in the northeast Atlantic Ocean.
    In addition to the proposed operations of the seismic airgun array 
and hydrophone streamer, L-DEO intends to operate a multibeam 
echosounder and a sub-bottom profiler continuously throughout the 
survey.
    Acoustic stimuli (i.e., increased underwater sound) generated 
during the operation of the seismic airgun array may have the potential 
to cause a 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 
20 species of marine mammals by Level B harassment. Take is not 
expected to result from the use of the multibeam echosounder or sub-
bottom profiler, for reasons discussed in this notice; nor is take 
expected to result from collision with the source vessel because it is 
a single vessel moving at a relatively slow speed (4.6 knots [kts]; 8.5 
kilometers per hour [km/hr]; 5.3 miles per hour [mph]) during seismic 
acquisition within the survey, for a relatively short period of time 
(approximately 39 days). It is likely that any marine mammal would be 
able to avoid the vessel.

Description of the Proposed Specified Activity

    L-DEO proposes to conduct a high energy, two-dimensional (2D) and 
three-dimensional (3D) seismic survey in the northeast Atlantic Ocean, 
west of Spain (see Figure 1 of the IHA application). Water depths in 
the survey area range from approximately 3,500 to greater than 5,000 
meters (m) (11,482.9 to 16,404.2 feet [ft]). The proposed seismic 
survey would be scheduled to occur for approximately 39 days during 
June 1 to July 14, 2013. Some minor deviation from these dates would be 
possible, depending on logistics and weather.
    L-DEO plans to use conventional seismic methodology in the Deep 
Galicia Basin of the northeast Atlantic Ocean. The goal of the proposed 
research is to collect data necessary to study rifted continental to 
oceanic crust transition in the Deep Galicia Basin west of Spain. This 
margin and its conjugate are among the best studied magma-poor, rifted 
margins in the world, and the focus of studies has been the faulting 
mechanics and modification of the upper mantle associated with such 
margins. Over the years, a combination of 2D reflection profiling, 
general marine geophysics, and ocean drilling have identified a number 
of interesting features of the margin. Among these are the S reflector, 
which has been interpreted to be detachment fault overlain with fault 
bounded, rotated, continental crustal blocks and underlain by 
serpentinized peridotite, and the Peridotite Ridge, composed of 
serpentized peridotite and thought to be upper mantle exhumed to the 
seafloor during rifting.
    To achieve the project's goals, the Principal Investigators (PIs), 
Drs. D. S. Sawyer (Rice University, J. K. Morgan (Rice University), and 
D. J. Shillington (L-DEO) propose to use a 3D seismic reflection 
survey, 2D survey, and a long-offset seismic program extending through 
the crust and S detachment into the upper mantle to characterize the 
last stage of continental breakup and the initiation of seafloor 
spreading, relate post-rifting subsidence to syn-rifting lithosphere 
deformation, and inform the nature of detachment faults. Ocean Bottom 
Seismometers (OBSs) and Ocean Bottom Hydrophones (OBHs) would also be 
deployed during the program. It is a cooperative program with 
scientists from the United Kingdom, Germany, Spain, and Portugal.

[[Page 17361]]

    The proposed survey would involve one source vessel, the R/V Marcus 
G. Langseth (Langseth). The Langseth would deploy an array of 18 
airguns as an energy source with a total volume of approximately 3,300 
in\3\. The receiving system would consist of four 6,000 m (19,685 ft) 
hydrophone streamers at 200 m (656.2 ft) spacing and up to 78 OBS and 
OBH instruments. The OBSs and OBHs would be deployed and retrieved by a 
second vessel, the R/V Poseidon (Poseidon), provided by the German 
Science Foundation. As the airgun array is towed along the survey 
lines, the hydrophone streamers would receive the returning acoustic 
signals and transfer the data to the on-board processing system. The 
OBS and OBHs record the returning acoustic signals internally for later 
analysis.
    A total of approximately 5,834 km (3150.1 nmi) of survey lines, 
including turns, will be shot in a grid pattern with a single line 
extending to the west (see Figure 1). There will be additional seismic 
operations in the survey area associated with equipment testing, ramp-
up, and possible line changes or repeat coverage of any areas where 
initial data quality is sub-standard. In L-DEO's estimated take 
calculations, 25% has been added for those additional operations.
    In addition to the operations of the airgun array, a Kongsberg EM 
122 multibeam echosounder and a Knudsen Chirp 3260 sub-bottom profiler 
will also be operated from the Langseth continuously throughout the 
survey. All planned geophysical data acquisition activities would be 
conducted by L-DEO with on-board assistance by the scientists who have 
proposed the study. The vessel will be self-contained, and the crew 
will live aboard the vessel for the entire cruise.

Vessel Specifications

    The Langseth, a seismic research vessel owned by the NSF, will tow 
the 36 airgun array, as well as the hydrophone streamer(s), along 
predetermined lines (see Figure 1 of the IHA application). When the 
Langseth is towing the airgun array and the hydrophone streamer(s), the 
turning rate of the vessel is limited to three degrees per minute (2.5 
km [1.5 mi]). Thus, the maneuverability of the vessel is limited during 
operations with the streamer. The vessel would ``fly'' the appropriate 
U.S. Coast Guard-approved day shapes (mast head signals used to 
communicate with other vessels) and display the appropriate lighting to 
designate the vessel has limited maneuverability.
    The vessel has a length of 71.5 m (235 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. 
The Langseth was designed as 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 ship is powered by two 3,550 horsepower (hp) Bergen BRG-6 diesel 
engines which drive two propellers directly. Each propeller has four 
blades and the shaft typically rotates at 750 revolutions per minute. 
The vessel also has an 800 hp bowthruster, which is not used during 
seismic acquisition. The Langseth's operation speed during seismic 
acquisition is typically 7.4 to 9.3 km per hour (hr) (km/hr) (4 to 5 
knots [kts]). When not towing seismic survey gear, the Langseth 
typically cruises at 18.5 km/hr (10 kts). The Langseth has a range of 
25,000 km (13,499 nmi) (the distance the vessel can travel without 
refueling).
    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 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. More details of the Langseth can be found in the IHA 
application and NSF/USGS PEIS.
    The Poseidon is a German-flagged vessel, owned by the Federal State 
of Schleswig-Holstein and operated by Briese Schiffahrts GmbH &Co. KG. 
The Poseidon has a length of 60.8 m (199.5 ft), a beam of 11.4 m (37.4 
ft), and a maximum draft of 4.7 m (15.4 ft). The ship is powered by 
diesel-electric propulsion. The traction motor produces 930 kW and 
drives one propeller directly. The propeller has five blades, and the 
shaft typically rotates at 220 revolutions per minute (rpm). The vessel 
also has a 394 hp bowthruster, which would not be used during OBS/OBH 
deployment and retrieval. The Poseidon typically cruises at 8.5 kt 
(11.5 km/hr) and has a range of 7,408 km (4,000 nmi).

Acoustic Source Specifications

Seismic Airguns
    The Langseth will deploy a 36-airgun array, consisting of two 18 
airgun (plus 2 spares) sub-arrays. Each sub-array will have a volume of 
approximately 3,300 cubic inches (in\3\). The airgun array will consist 
of a mixture of Bolt 1500LL and Bolt 1900LLX airguns ranging in size 
from 40 to 360 in\3\, with a firing pressure of 1,900 pounds per square 
inch (psi). The 18 airgun sub-arrays will be configured as two 
identical linear arrays or ``strings'' (see Figure 2.11 of the NSF/USGS 
PEIS). Each string will have 10 airguns, the first and last airguns in 
the strings are spaced 16 m (52.5 ft) apart. Of the 10 airguns, nine 
airguns in each string will be fired simultaneously (1,650 in\3\), 
whereas the tenth is kept in reserve as a spare, to be turned on in 
case of failure of another airgun. The sub-arrays would be fired 
alternately during the survey. The two airgun sub-arrays will be 
distributed across an area of approximately 12 x 16 m (40 x 52.5 ft) 
behind the Langseth and will be towed approximately 140 m (459.3 ft) 
behind the vessel. Discharge intervals depend on both the ship's speed 
and Two Way Travel Time recording intervals. The shot interval will be 
37.5 m (123 ft) during the study. The shot interval will be relatively 
short, approximately 15 to 20 seconds (s) based on an assumed boat 
speed of 4.5 knots. During firing, a brief (approximately 0.1 s) pulse 
sound is emitted; the airguns will be silent during the intervening 
periods. The dominant frequency components range from two to 188 Hertz 
(Hz).
    The tow depth of the airgun array will be 9 m (29.5 ft) during the 
surveys. Because the actual source is a distributed sound source (18 
airguns) rather than a single point source, the highest sound 
measurable at any location in the water will be less than the nominal 
source level. In addition, the effective source level for sound 
propagating in near-horizontal directions will be substantially lower 
than the nominal omni-directional source level applicable to downward 
propagation because of the directional nature of the sound from the 
airgun array (i.e., sound is directed downward).

Hydrophone Streamer

    Acoustic signals will be recorded using a system array of four 
hydrophone streamers, which would be towed behind the Langseth. Each 
streamer would consist of Sentry Solid Streamer Sercel cable 
approximately 6 km (3.2 nmi) long. The streamers are attached by floats 
to a diverter cable, which keeps the streamer spacing at approximately 
100 to 150 m (328 to 492 ft) apart.
    Seven hydrophones will be present along each streamer for acoustic 
measurement. The hydrophones will consist of a mixture of Sonardyne 
Transceivers. Each streamer will contain three groups of paired 
hydrophones, with each group approximately 2,375 m (7,800 ft) apart. 
The hydrophones within each group will be approximately 300 m (984 ft) 
apart. One additional hydrophone will be located

[[Page 17362]]

on the tail buoy attached to the end of the streamer cable. In 
addition, one Sonardyne Transducer will be attached to the airgun 
array. Compass birds will be used to keep the streamer cables and 
hydrophones at a depth of approximately 10 m (32.8 ft). One compass 
bird will be placed at the front end of each streamer as well as 
periodically along the streamer.

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-to-peak (p-p), or the root mean square (rms). Root mean 
square (rms), 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 arrays used by L-DEO on the 
Langseth are 236 to 265 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). The 
specific source output for the 18 airgun array is 252 dB (peak) and 259 
dB (p-p). However, the difference between rms and peak or peak-to-peak 
values for a given pulse depends on the frequency content and duration 
of the pulse, among other factors.
    Accordingly, L-DEO have predicted the received sound levels in 
relation to distance and direction from the 18 airgun array and the 
single Bolt 1900LL 40 in\3\ airgun, which will be used during power-
downs. A detailed description of L-DEO modeling for this survey's 
marine seismic source arrays for protected species mitigation is 
provided in the NSF/USGS PEIS (see Appendix H). NMFS refers the 
reviewers to the IHA application and NSF/USGS PEIS documents for 
additional information.

Predicted Sound Levels for the Airguns

    Tolstoy et al. (2009) reported results for propagation measurements 
of pulses from the Langseth's 36 airgun, 6,600 in\3\ array in shallow-
water (approximately 50 m [164 ft]) and deep water depths 
(approximately 1,600 m [5,249 ft]) in the Gulf of Mexico in 2007 and 
2008. Results of the Gulf of Mexico calibration study (Tolstoy et al., 
2009) showed that radii around the airguns for various received levels 
varied with water depth and that sound propagation varied with array 
tow depth.
    The L-DEO used the results from the Gulf of Mexico study to 
determine the algorithm for its model that calculates the mitigation 
exclusion zones for the 36-airgun array and the single airgun. L-DEO 
has used these calculated values to determine buffer (i.e., 160 dB) and 
exclusion zones for the 18 airgun array and previously modeled 
measurements by L-DEO for the single airgun, to designate exclusion 
zones for purposes of mitigation, and to estimate take for marine 
mammals in the northeast Atlantic Ocean. A detailed description of the 
modeling effort is provided in the NSF/USGS PEIS.
    Comparison of the Tolstoy et al. (2009) calibration study with the 
L-DEO's model for the Langseth's 36-airgun array indicated that the 
model represents the actual received levels, within the first few 
kilometers and the locations of the predicted exclusion zones. 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. Because the tow depth 
of the array in the calibration study is less shallow (6 m [19.7 ft]) 
than the tow depths in the proposed survey (9 m [29.5 ft), L-DEO used 
the following correction factors for estimating the received levels 
during the proposed surveys (see Table 1). The correction factors are 
the ratios of the 160, 180, and 190 dB distances from the modeled 
results for the 6,600 in\3\ airgun arrays towed at 6 m (19.7 ft) versus 
9, 12, or 15 m (29.5, 39.4, or 49.2 ft) (LGL, 2008).
    For a single airgun, the tow depth has minimal effect on the 
maximum near-field output and the shape of the frequency spectrum for 
the single airgun; thus, the predicted exclusion zones are essentially 
the same at different tow depths. The L-DEO's model does not allow for 
bottom interactions, and thus is most directly applicable to deep 
water.
    Using the model (airgun array and single airgun), Table 1 (below) 
shows the distances at which three rms sound levels are expected to be 
received from the 18 airgun array and a single airgun. To avoid the 
potential for injury or permanent physiological damage (Level A 
harassment), NMFS's (1995, 2000) current practice is that cetaceans and 
pinnipeds should not be exposed to pulsed underwater noise at received 
levels exceeding 180 dB re: 1 [micro]Pa and 190 dB re: 1 [micro]Pa, 
respectively. L-DEO used these levels to establish the proposed 
exclusion zones. If marine mammals are detected within or about to 
enter the appropriate exclusion zone, the airguns will be powered-down 
(or shut-down, if necessary) immediately. NMFS also assumes that marine 
mammals exposed to levels exceeding 160 dB re: 1 [micro]Pa may 
experience Level B harassment.
    Table 1 summarizes the predicted distances at which sound levels 
(160, 180, and 190 dB [rms]) are expected to be received from the 18 
airgun array and a single airgun operating in deep water depths.

[[Page 17363]]



  Table 1--Measured (Array) or Predicted (Single Airgun) Distances to Which Sound Levels >=190, 180, and 160 dB
 re: 1 [mu]Pa (rms) Could Be Received in Deep Water During the Proposed Survey in the Northeast Atlantic Ocean,
                                               June to July, 2013
----------------------------------------------------------------------------------------------------------------
                                                                                   Predicted RMS radii distances
                                                                    Water depth                 (m)
             Sound source and volume              Tow depth  (m)        (m)      -------------------------------
                                                                                      180 dB          160 dB
----------------------------------------------------------------------------------------------------------------
Single Bolt airgun (40 in\3\)...................               9        >1,000 m           100 m           388 m
                                                                                      (328.1 ft)      (1,273 ft)
18 airguns (3,300 in\3\)........................               9        >1,000 m         1,116 m         6,908 m
                                                                                    (3,661.4 ft)     (22,664 ft)
----------------------------------------------------------------------------------------------------------------

    Along with the airgun operations, two additional acoustical data 
acquisition systems will be operated from the Langseth continuously 
during the survey. The ocean floor will be mapped with the Kongsberg EM 
122 multibeam echosounder and a Knudsen 320B sub-bottom profiler. These 
sound sources will be operated continuously from the Langseth 
throughout the cruise.

Multibeam Echosounder

    The Langseth will operate a Kongsberg EM 122 multibeam echosounder 
concurrently during airgun operations to map characteristics of the 
ocean floor. The hull-mounted multibeam echosounder emits brief pulses 
of sound (also called a ping) (10.5 to 13, usually 12 kHz) in a fan-
shaped beam that extends downward and to the sides of the ship. The 
transmitting beamwidth is 1[deg] or 2[deg] fore-aft and 150[deg] 
athwartship and the maximum source level is 242 dB re: 1 [mu]Pa.
    Each ping consists of eight (in water greater than 1,000 m) or four 
(less than 1,000 m) successive, fan-shaped transmissions, each 
ensonifying a sector that extends 1[deg] fore-aft. Continuous-wave 
pulses increase from 2 to 15 milliseconds (ms) long in water depths up 
to 2,600 m (8,350.2 ft), and frequency modulated (FM) chirp pulses up 
to 100 ms long are used in water greater than 2,600 m. The successive 
transmissions span an overall cross-track angular extent of about 
150[deg], with 2 ms gaps between the pulses for successive sectors (see 
Table 1 of the IHA application).

Sub-Bottom Profiler

    The Langseth will also operate a Knudsen Chirp 320B sub-bottom 
continuously throughout the cruise simultaneously with the multibeam 
echosounder to map and provide information about the sedimentary 
features and bottom topography. The beam is transmitted as a 27[deg] 
cone, which is directed downward by a 3.5 kHz transducer in the hull of 
the Langseth. The maximum output is 1 kilowatt (kW), but in practice, 
the output varies with water depth. The pulse interval is one second, 
but a common mode of operation is to broadcast five pulses at one 
second intervals followed by a 5-second pause.
    Both the multibeam echosounder and sub-bottom profiler are operated 
continuously during survey operations. Given the relatively shallow 
water depths of the survey area (20 to 300 m [66 to 984 ft]), the 
number of pings or transmissions would be reduced from 8 to 4, and the 
pulse durations would be reduced from 100 ms to 2 to 15 ms for the 
multibeam echosounder. Power levels of both instruments would be 
reduced from maximum levels to account for water depth. Actual 
operating parameters will be established at the time of the survey.
    NMFS expects that acoustic stimuli resulting from the proposed 
operation of the single airgun or the 18 airgun array has the potential 
to harass 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 (approximately 4.6 knots [kts]; 8.5 km/hr; 5.3 mph) 
during seismic acquisition.

Dates, Duration, and Specified Geographic Region

    The proposed survey would encompass the area between approximately 
41.5 to 42.5[deg] North and approximately 11.5 to 17.5[deg] West in the 
northeast Atlantic Ocean to the west of Spain. The cruise will be in 
International Waters and in the Exclusive Economic Zone (EEZ) of Spain 
in water depts. In the range from approximately 3,500 to greater than 
5,000 m (see Figure 1 of the IHA application). The exact dates of the 
proposed activities depend on logistics and weather conditions. The 
Langseth would depart from Lisbon, Portugal or Vigo, Spain on June, 1, 
2013 and spend approximately 1 day in transit to the proposed survey 
area. The seismic survey is expected to take approximately 39 days, 
with completion on approximately July 12, 2013. When the survey is 
completed, the Langseth will then transit back to Lisbon, Portugal or 
Vigo, Spain.
Description of the Marine Mammals in the Area of the Proposed Specified 
Activity
    Thirty-nine marine mammal species (36 cetaceans [whales, dolphins, 
and porpoises]) (29 odontocetes and 7 mysticetes] and 3 pinnipeds 
[seals and sea lions]) are known to or could occur in the eastern North 
Atlantic study area. Several of these species are listed as endangered 
under the U.S. Endangered Species Act of 1973 (ESA; 16 U.S.C. 1531 et 
seq.), including the North Atlantic right (Eubalaena glacialis), 
humpback (Megaptera novaeangliae), sei (Balaenoptera borealis), fin 
(Balaenoptera physalus), blue (Balaenoptera musculus), and sperm 
(Physeter macrocephalus) whales. Nine cetacean species, although 
present in the wider eastern North Atlantic ocean, likely would not be 
found near the proposed study area at approximately 42[deg] North 
because their ranges generally do not extend south of approximately 
45[deg] North in the northeastern Atlantic waters (i.e., Atlantic 
white-sided dolphin [Lagenorhynchus acutus] and white-beaked dolphin 
[Lagenorhynchus albirostris]), or their ranges in the northeast 
Atlantic ocean generally do not extend north of approximately 20[deg] 
North (Clymene dolphin [Stenella clymene]), 30[deg] North (Fraser's 
dolphin [Lagenodelphis hosei]), 34[deg] North (spinner dolphin 
[Stenella longirostris]), 35 [deg] North (melon-headed whale 
[Peponocephala electra]), 37[deg] North (rough-toothed dolphin [Steno 
bredandensis]), or 40[deg] North (Bryde's whale [Balaenoptera brydei] 
and pantropical spotted dolphin [Stenella attenuata]). Although Spitz 
et al. (2011) reported two strandings records of

[[Page 17364]]

melon-headed whales for the Bay of Biscay, this species will not be 
discussed further, as it is unlikely to occur in the proposed survey 
area.
    The harbor porpoise (Phocoena phocoena) does not occur in deep 
offshore waters. No harbor porpoise were detected visually or 
acoustically during summer surveys off the continental shelf in the 
Biscay Bay area during 1989 and 2007 (Lens, 1991; Basto d'Andrade, 
2008; Anonymous, 2009). Pinniped species are also not known to occur in 
the deep waters of the survey area.
    General information on the taxonomy, ecology, distribution, and 
movements, and acoustic capabilities of marine mammals are given in 
sections 3.6.1 and 3.7.1 of the NSF/USGS PEIS. One of the qualitative 
analysis areas defined in the PEIS is on the Mid-Atlantic Ridge, at 
26[deg] North, 40[deg] West, approximately 2,800 km (1,511.9 nmi) from 
the proposed survey area. The general distribution of mysticetes and 
odontocetes in the North Atlantic Ocean is discussed in sections 
3.6.3.4 and 3.7.3.4 of the NSF/USGS PEIS, respectively. The rest of 
this section deals specifically with species distribution off the north 
and west coast of the Iberian Peninsula.
    Several systematic surveys have been conducted in the Bay of Biscay 
area, which has been found to be one of the most productive areas and 
the centre of highest cetacean diversity in the northeast Atlantic 
Ocean (Hoyt, 2005). The second North Atlantic Sightings Survey (NASS) 
occurred in waters off the continental shelf from the southern U.K. to 
northern Spain in July to August, 1989 (Lens, 1991). The Cetacean 
Offshore Distribution and Abundance in the European Atlantic (CODA) 
included surveys from the U.K. to southern Spain during July, 2007 
(Basto d'Andrade, 2008; Anonymous, 2009). Additional information is 
available from coastal surveys off northwest Spain (e.g., Lopez et al., 
2003), and sighting records off western central (Brito et al., 2009) 
and southern Portugal (Castor et al., 2010). Records from the Ocean 
Biogeographic Information System (OBIS) database hosted by Rutgers and 
Duke University (Read et al., 2009) were also included.
    Table 2 (below) presents information on the abundance, 
distribution, population status, conservation status, and population 
trend of the species of marine mammals that may occur in the proposed 
study area during June to July, 2013.

  Table 2--The Habitat, Regional Abundance, and Conservation Status of Marine Mammals That May Occur in or Near the Proposed Seismic Survey Area in the
                                                                Northeast Atlantic Ocean
                                           [See text and Table 3 in L-DEO's application for further details.]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Population estimate in the
             Species                     Habitat                North Atlantic                      ESA\1\                          MMPA \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes:
    North Atlantic right whale     Pelagic, shelf and   396 \3\.......................  EN............................  D.
     (Eubalaena glacialis).         coastal.
    Humpback whale (Megaptera      Mainly nearshore,    11,570 \4\....................  EN............................  D.
     novaeangliae).                 banks.
    Minke whale (Balaenoptera      Pelagic and coastal  121,000 \5\...................  NL............................  NC.
     acutorostrata).
    Sei whale (Balaenoptera        Primarily offshore,  12,000 to 13,000 \6\..........  EN............................  D.
     borealis).                     pelagic.
    Fin whale (Balaenoptera        Continental slope,   24,887 \7\....................  EN............................  D.
     physalus).                     pelagic.
    Blue whale (Balaenoptera       Pelagic, shelf,      937 \8\.......................  EN............................  D.
     musculus).                     coastal.
Odontocetes:
    Sperm whale (Physeter          Pelagic, deep sea..  13,190 \9\....................  EN............................  D.
     macrocephalus).
    Pygmy sperm whale (Kogia       Deep waters off the  395 3 10......................  NL............................  NC.
     breviceps).                    shelf.
    Dwarf sperm whale (Kogia       Deep waters off the                                  NL............................  NC.
     sima).                         shelf.
    Cuvier's beaked whale          Slope and Pelagic..  6,992 \11\....................  NL............................  NC.
     (Ziphius cavirostris).                             100,000 \12\..................
    Northern bottlenose whale      Pelagic............  40,000 \13\...................  NL............................  NC.
     (Hyperoodon ampullatus).
    True's beaked whale            Pelagic............  6,992 \11\....................  NL............................  NC.
     (Mesoplodon mirus).
    Gervais' beaked whale          Pelagic............  6,992 \11\....................  NL............................  NC.
     (Mesoplodon europaeus).
    Sowerby's beaked whale         Pelagic............  6,992 \11\....................  NL............................  NC.
     (Mesoplodon bidens).
    Blainville's beaked whale      Pelagic............  6,992 \11\....................  NL............................  NC.
     (Mesoplodon densirostris).
    Bottlenose dolphin (Tursiops   Coastal, oceanic,    19,295 \14\...................  NL............................  NC D--Western North Atlantic
     truncatus).                    shelf break.                                                                         coastal.
    Atlantic spotted dolphin       Shelf, offshore....  50,978 \3\....................  NL............................  NC.
     (Stenella frontalis).
    Striped dolphin (Stenella      Off continental      67,414 \14\...................  NL............................  NC.
     coeruleoalba).                 shelf.
    Short-beaked common dolphin    Shelf, pelagic,      116,709 \14\..................  NL............................  NC.
     (Delphinus delphis).           seamounts.
    Risso's dolphin (Grampus       Deep water,          20,479 \3\....................  NL............................  NC.
     griseus).                      seamounts.
    Pygmy killer whale (Feresa     Pelagic............  NA............................  NL............................  NC.
     attenuata).
    False killer whale (Pseudorca  Pelagic............  NA............................  NL............................  NC.
     crassidens).

[[Page 17365]]

 
    Killer whale (Orcinus orca)..  Pelagic, shelf,      NA............................  NL EN--Southern resident......  NC D--Southern resident, AT1
                                    coastal.                                                                             transient.
    Short-finned pilot whale       Pelagic, shelf       780,000 \15\..................  NL............................  NC.
     (Globicephala macrorhynchus).  coastal.
    Long-finned pilot whale        Mostly pelagic.....                                  NC............................  NC.
     (Globicephala melas).
--------------------------------------------------------------------------------------------------------------------------------------------------------
NA = Not available or not assessed.
\1\ U.S. Endangered Species Act: EN = Endangered, T = Threatened, DL = Delisted, NL = Not listed.
\2\ U.S. Marine Mammal Protection Act: D = Depleted, NC = Not Classified.
\3\ Western North Atlantic, in U.S. and southern Canadian waters (Waring et al., 2012).
\4\ Likely negatively biased (Stevick et al., 2003).
\5\ Central and Northeast Atlantic (IWC, 2012).
\6\ North Atlantic (Cattanach et al., 1993).
\7\ Central and Northeast Atlantic (Vikingsson et al., 2009).
\8\ Central and Northeast Atlantic (Pike et al., 2009).
\9\ For the northeast Atlantic, Faroes-Iceland, and the U.S. east coast (Whitehead, 2002).
\10\ Both Kogia species.
\11\ For all beaked whales (Anonymous, 2009).
\12\ Worldwide estimate (Taylor et al., 2008).
\13\ Eastern North Atlantic (NAMMCO, 1995).
\14\ European Atlantic waters beyond the continental shelf (Anonymous, 2009).
\15\ Globicephala spp. combined, Central and Eastern North Atlantic (IWC, 2012).

    Refer to sections 3 and 4 of L-DEO's application for detailed 
information regarding the abundance and distribution, population 
status, and life history and behavior of these other marine mammal 
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 hearing impairment, or non-auditory 
physical or physiological effects (Richardson et al., 1995; Gordon et 
al., 2004; Nowacek et al., 2007; Southall et al., 2007). Permanent 
hearing impairment, in the unlikely event that it occurred, would 
constitute injury, but temporary threshold shift (TTS) is not an injury 
(Southall et al., 2007). Although the possibility cannot be entirely 
excluded, it is unlikely that the proposed project would result in any 
cases of temporary or permanent hearing impairment, or any significant 
non-auditory physical or physiological effects. Based on the available 
data and studies described here, some behavioral disturbance is 
expected. A more comprehensive review of these issues can be found in 
the ``Programmatic Environmental Impact Statement/Overseas 
Environmental Impact Statement prepared for Marine Seismic Research 
that is funded by the National Science Foundation and conducted by the 
U.S. Geological Survey'' (NSF/USGS, 2011).

Tolerance

    Richardson et al. (1995) defines tolerance as the occurrence of 
marine 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. 
Several studies have shown that marine mammals at distances more than a 
few kilometers from operating seismic vessels often show no apparent 
response. That is often true even in cases when the pulsed sounds must 
be readily audible to the animals based on measured received levels and 
the hearing sensitivity of the marine mammal group. Although various 
baleen whales and toothed whales, and (less frequently) pinnipeds have 
been shown to react behaviorally to airgun pulses under some 
conditions, at other times marine mammals of all three types have shown 
no overt reactions. The relative responsiveness of baleen and toothed 
whales are quite variable.

Masking

    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

[[Page 17366]]

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 North Atlantic 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). Dilorio and Clark (2009) found 
evidence of increased calling by blue whales during operations by a 
lower-energy seismic source (i.e., sparker). 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.
    Marine mammals are thought to be able to compensate for masking by 
adjusting their acoustic behavior through shifting call frequencies, 
increasing call volume, and increasing vocalization rates. For example, 
blue whales are found to increase call rates when exposed to noise from 
seismic surveys in the St. Lawrence Estuary (Dilorio and Clark, 2009). 
The North Atlantic right whales (Eubalaena glacialis) exposed to high 
shipping noise increased call frequency (Parks et al., 2007), while 
some humpback whales respond to low-frequency active sonar playbacks by 
increasing song length (Miller et al., 2000). In general, NMFS expects 
the masking effects of seismic pulses to be minor, given the normally 
intermittent nature of seismic pulses.

Behavioral Disturbance

    Marine mammals may behaviorally react to sound when exposed to 
anthropogenic noise. 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). These behavioral 
reactions are often shown as: changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke slapping or jaw 
clapping); avoidance of areas where noise sources are located; and/or 
flight responses (e.g., pinnipeds flushing into the water from haul-
outs or rookeries). 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).
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be expected to be biologically significant if the 
change affects growth, survival, and/or reproduction. Some of these 
significant behavioral modifications include:
     Change in diving/surfacing patterns (such as those thought 
to be causing beaked whale stranding due to exposure to military mid-
frequency tactical sonar);
     Habitat abandonment due to loss of desirable acoustic 
environment; and
     Cessation of feeding or social interaction.
    The onset of behavioral disturbance from anthropogenic noise 
depends on both external factors (characteristics of noise sources and 
their paths) and the receiving animals (hearing, motivation, 
experience, demography) and is also difficult to predict (Richardson et 
al., 1995; Southall et al., 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 sound. In most cases, this approach 
likely overestimates the numbers of marine mammals that would be 
affected in some biologically-important manner.
    Baleen Whales--Baleen whales generally tend to avoid operating 
airguns, but avoidance radii are quite variable (reviewed in Richardson 
et al., 1995; Gordon et al., 2004). 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, 
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 (rms) 
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 4 to 15 km (2.2 to 
8.1 nmi) 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 have 
shown that some species of baleen whales, notably bowhead, gray, and 
humpback whales, at times, show strong avoidance at received levels 
lower than 160 to 170 dB re 1 [mu]Pa (rms).
    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 airgun (20 in\3\) with 
source level of 227 dB re 1 [micro]Pa (p-p). In the 1998 study, they 
documented that avoidance reactions began at 5 to 8 km (2.7 to 4.3 nmi) 
from the array, and that those reactions kept most pods approximately 3 
to 4 km (1.6 to 2.2 nmi) from the operating seismic boat. In the 2000 
study, they noted localized displacement during migration of 4 to 5 km 
(2.2 to 2.7 nmi) by traveling pods and 7 to 12 km (3.8 to 6.5 nmi) by 
more sensitive resting pods of cow-calf pairs. Avoidance distances with 
respect to the

[[Page 17367]]

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 (rms) for humpback pods containing females, and at the mean 
closest point of approach distance the received level was 143 dB re 1 
[mu]Pa (rms). The initial avoidance response generally occurred at 
distances of 5 to 8 km (2.7 to 4.3 nmi) from the airgun array and 2 km 
(1.1 nmi) 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 (rms).
    Data collected by observers during several seismic surveys in the 
Northwest Atlantic 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 vs. non-seismic periods (Moulton and 
Holst, 2010).
    Humpback whales on their summer feeding grounds in southeast Alaska 
did not exhibit persistent avoidance when exposed to seismic pulses 
from a 1.64-L (100 in\3\) airgun (Malme et al., 1985). Some humpbacks 
seemed ``startled'' at received levels of 150 to 169 dB re 1 [mu]Pa. 
Malme et al. (1985) concluded that there was no clear evidence of 
avoidance, despite the possibility of subtle effects, at received 
levels up to 172 dB re 1 [mu]Pa (rms). However, Moulton and Holst 
(2010) reported that humpback whales monitored during seismic surveys 
in the Northwest Atlantic had lower sighting rates and were most often 
seen swimming away from the vessel during seismic periods compared with 
periods when airguns were silent.
    Studies have suggested that South Atlantic humpback whales 
wintering off Brazil may be displaced or even strand upon exposure to 
seismic surveys (Engel et al., 2004). The evidence for this was 
circumstantial and subject to alternative explanations (IAGC, 2004). 
Also, the evidence was not consistent with subsequent results from the 
same area of Brazil (Parente et al., 2006), or with direct studies of 
humpbacks exposed to seismic surveys in other areas and seasons. After 
allowance for data from subsequent years, there was ``no observable 
direct correlation'' between strandings and seismic surveys (IWC, 2007: 
236).
    Reactions of migrating and feeding (but not wintering) gray whales 
to seismic surveys have been studied. Malme et al. (1986, 1988) studied 
the responses of feeding eastern Pacific gray whales to pulses from a 
single 100 in\3\ airgun off St. Lawrence Island in the northern Bering 
Sea. They estimated, based on small sample sizes, that 50 percent of 
feeding gray whales stopped feeding at an average received pressure 
level of 173 dB re 1 [mu]Pa on an (approximate) rms basis, and that 10 
percent of feeding whales interrupted feeding at received levels of 163 
dB re 1 [mu]Pa (rms). 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) 
reported that singing fin whales in the Mediterranean moved away from 
an operating airgun array.
    Ship-based monitoring studies of baleen whales (including blue, 
fin, sei, minke, and humpback whales) in the Northwest Atlantic found 
that overall, this group had lower sighting rates during seismic vs. 
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).
    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, 2010). 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 Angliss, 2010). The history 
of coexistence between seismic surveys and baleen whales suggests that 
brief exposures to sound pulses from any single seismic survey are 
unlikely to result in prolonged effects.
    Toothed Whales--Little systematic information is available about 
reactions of toothed whales to noise pulses. Few studies similar to the 
more extensive baleen whale/seismic pulse work summarized above 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 PSOs on seismic vessels regularly see 
dolphins and other small toothed whales near

[[Page 17368]]

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.
    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 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. However, controlled exposure experiments in the Gulf 
of Mexico indicate that foraging behavior was altered upon exposure to 
airgun sound (Jochens et al., 2008; Miller et al., 2009; Tyack, 2009).
    There are almost no specific data on the behavioral reactions of 
beaked whales to seismic surveys. However, some northern bottlenose 
whales (Hyperoodon ampullatus) remained in the general area and 
continued to produce high-frequency clicks when exposed to sound pulses 
from distant seismic surveys (Gosselin and Lawson, 2004; Laurinolli and 
Cochrane, 2005; Simard et al., 2005). Most beaked whales tend to avoid 
approaching vessels of other types (e.g., Wursig et al., 1998). They 
may also dive for an extended period when approached by a vessel (e.g., 
Kasuya, 1986), although it is uncertain how much longer such dives may 
be as compared to dives by undisturbed beaked whales, which also are 
often quite long (Baird et al., 2006; Tyack et al., 2006). Based on a 
single observation, Aguilar-Soto et al. (2006) suggested that foraging 
efficiency of Cuvier's beaked whales may be reduced by close approach 
of vessels. In any event, it is likely that most beaked whales would 
also show strong avoidance of an approaching seismic vessel, although 
this has not been documented explicitly. 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 indications that some beaked whales may 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 some 
mysticetes. However, other data suggest that some odontocete species, 
including harbor porpoises, may be more responsive than might be 
expected given their poor low-frequency hearing. Reactions at longer 
distances may be particularly likely when sound propagation conditions 
are conducive to transmission of the higher frequency components of 
airgun sound to the animals' location (DeRuiter et al., 2006; Goold and 
Coates, 2006; Tyack et al., 2006; Potter et al., 2007).

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, 
Carder, Schlundt, and Ridgway, 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 (above) 
presents the estimated distances from the Langseth's airguns at which 
the received energy level (per pulse, flat-weighted) would be

[[Page 17369]]

expected to be greater than or equal to 180 or 190 dB re 1 [mu]Pa 
(rms).
    To avoid the potential for injury (i.e., Level A harassment), NMFS 
(1995, 2000) concluded that cetaceans and pinnipeds should not be 
exposed to pulsed underwater noise at received levels exceeding 180 and 
190 dB re 1 [mu]Pa (rms), respectively. NMFS believes that to avoid the 
potential for Level A harassment, cetaceans and pinnipeds should not be 
exposed to pulsed underwater noise at received levels exceeding 180 and 
190 dB re 1 [mu]Pa (rms), respectively. The established 180 and 190 dB 
(rms) criteria are not considered to be the levels above which TTS 
might occur. Rather, they are the received levels above which, in the 
view of a panel of bioacoustics specialists convened by NMFS before TTS 
measurements for marine mammals started to become available, one could 
not be certain that there would be no injurious effects, auditory or 
otherwise, to marine mammals. NMFS also assumes that cetaceans and 
pinnipeds exposed to levels exceeding 160 dB re 1 [mu]Pa (rms) may 
experience Level B harassment.
    For toothed whales, researchers have derived TTS information for 
odontocetes from studies on the bottlenose dolphin and beluga. The 
experiments show that exposure to a single impulse at a received level 
of 207 kPa (or 30 psi, p-p), which is equivalent to 228 dB re 1 Pa (p-
p), resulted in a 7 and 6 dB TTS in the beluga whale at 0.4 and 30 kHz, 
respectively. Thresholds returned to within 2 dB of the pre-exposure 
level within 4 minutes of the exposure (Finneran et al., 2002). 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 than those of odontocetes (Southall et 
al., 2007).
    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 (Southall et al., 2007). 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. 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 6 
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. Some pinnipeds show avoidance 
reactions to airguns, but their avoidance reactions are generally not 
as strong or consistent as those of cetaceans, and occasionally they 
seem to be attracted to operating seismic vessels (NMFS, 2010).
    Stranding and Mortality--When a living 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.''
    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 mid-frequency active

[[Page 17370]]

sonar use in which exposure to sonar is believed to have been a 
contributing factor to strandings: Greece (1996); the Bahamas (2000); 
Madeir (2000); Canary Islands (2002); and Spain (2006). Refer 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--Marine mammals close 
to underwater detonations of high explosives can be killed or severely 
injured, and the auditory organs are especially susceptible to injury 
(Ketten et al., 1993; Ketten, 1995). However, explosives are no longer 
used in marine waters for commercial seismic surveys or (with rare 
exceptions) for seismic research. These methods have been replaced 
entirely by airguns or related non-explosive pulse generators. Airgun 
pulses are less energetic and have slower rise times, and there is no 
specific evidence that they can cause serious injury, death, or 
stranding even in the case of large airgun arrays. However, the 
association of strandings of beaked whales with naval exercises 
involving mid-frequency active sonar (non-pulse sound) and, in one 
case, the co-occurrence of an L-DEO seismic survey (Malakoff, 2002; Cox 
et al., 2006), has raised the possibility that beaked whales exposed to 
strong ``pulsed'' sounds could also be susceptible to injury and/or 
behavioral reactions that can lead to stranding (e.g., Hildebrand, 
2005; Southall et al., 2007).
    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 indications that gas-bubble disease 
(analogous to ``the bends''), induced in supersaturated tissue by a 
behavioral response to acoustic exposure, could be a pathologic 
mechanism for the strandings and mortality of some deep-diving 
cetaceans exposed to sonar. The evidence for this remains 
circumstantial and associated with exposure to naval mid-frequency 
sonar, not seismic surveys (Cox et al., 2006; Southall et al., 2007).
    Seismic pulses and mid-frequency sonar signals are quite different, 
and some mechanisms by which sonar sounds have been hypothesized to 
affect beaked whales are unlikely to apply to airgun pulses. Sounds 
produced by airgun arrays are broadband impulses with most of the 
energy below one kHz. Typical military mid-frequency sonar emits non-
impulse sounds at frequencies of 2 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 expect that the same to marine mammals will result from 
military sonar and seismic surveys. 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 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 and the seismic surveys was inconclusive and not 
based on any physical evidence (Hogarth, 2002; Yoder, 2002). 
Nonetheless, the Gulf of California incident plus the beaked whale 
strandings near naval exercises involving use of mid-frequency sonar 
suggests a need for caution in conducting seismic surveys in areas 
occupied by beaked whales until more is known about effects of seismic 
surveys on those species (Hildebrand, 2005). No injuries of beaked 
whales are anticipated during the proposed study because of:
    (1) The high likelihood that any beaked whales nearby would avoid 
the approaching vessel before being exposed to high sound levels, 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, 
some odontocetes, and some pinnipeds, 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 multibeam echosounder from 
the source vessel during the planned study. Sounds from the multibeam 
echosounder 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 multibeam echosounder is at frequencies near 12 
kHz, and the

[[Page 17371]]

maximum source level is 242 dB re 1 [mu]Pa (rms). 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 (in water less than 1,000 m deep) successive fan-shaped 
transmissions (segments) at different cross-track angles. Any given 
mammal at depth near the trackline would be in the main beam for only 
one or two of the nine segments. Also, marine mammals that encounter 
the Kongsberg EM 122 are unlikely to be subjected to repeated pulses 
because of the narrow fore-aft width of the beam and will receive only 
limited amounts of pulse energy because of the short pulses. Animals 
close to the ship (where the beam is narrowest) are especially unlikely 
to be ensonified for more than one 2 to 15 ms pulse (or two pulses if 
in the overlap area). Similarly, Kremser et al. (2005) noted that the 
probability of a cetacean swimming through the area of exposure when a 
multibeam echosounder 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 multibeam echosounder. The area of 
possible influence of the multibeam echosounder 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 a multibeam echosounder on marine 
mammals are described below.
    Masking--Marine mammal communications will not be masked 
appreciably by the multibeam echosounder 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 multibeam echosounder 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 (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 [mu]Pa, gray whales reacted by orienting slightly away 
from the source and being deflected from their course by approximately 
200 m (656.2 ft) (Frankel, 2005). When a 38 kHz echosounder and a 150 
kHz acoustic Doppler current profiler were transmitting during studies 
in the Eastern Tropical Pacific, baleen whales showed no significant 
responses, while spotted and spinner dolphins were detected slightly 
more often and beaked whales less often during visual surveys 
(Gerrodette and Pettis, 2005).
    Captive bottlenose dolphins and a beluga whale exhibited changes in 
behavior when exposed to 1 s tonal signals at frequencies similar to 
those that will be emitted by the multibeam echosounder 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 a multibeam 
echosounder.
    Hearing Impairment and Other Physical Effects--Given recent 
stranding events that have been associated with the operation of naval 
sonar, there is concern that mid-frequency sonar sounds can cause 
serious impacts to marine mammals (see above). However, the multibeam 
echosounder proposed for use by L-DEO is quite different than sonar 
used for Navy operations. Pulse duration of the multibeam echosounder 
is very short relative to the naval sonar. Also, at any given location, 
an individual marine mammal would be in the beam of the multibeam 
echosounder for much less time given the generally downward orientation 
of the beam and its narrow fore-aft beamwidth; Navy sonar often uses 
near-horizontally-directed sound. Those factors would all reduce the 
sound energy received from the multibeam echosounder rather drastically 
relative to that from naval sonar.
    NMFS believes that the brief exposure of marine mammals to one 
pulse, or small numbers of signals, from the multibeam echosounder is 
not likely to result in the harassment of marine mammals.

Sub-Bottom Profiler

    L-DEO will also operate a sub-bottom profiler from the source 
vessel during the proposed survey. Sounds from the sub-bottom profiler 
are very short pulses, occurring for 1 to 4 ms once every second. Most 
of the energy in the sound pulses emitted by the sub-bottom profiler is 
at 3.5 kHz, and the beam is directed downward. The sub-bottom profiler 
on the Langseth has a maximum source level of 204 dB re 1 [mu]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 a sub-bottom profiler 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 sub-bottom profiler 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 sub-bottom profiler 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 sub-
bottom profiler are likely to be similar to those for other pulsed 
sources if received at the same levels. However, the pulsed signals 
from the sub-bottom profiler are considerably weaker than those from 
the multibeam echosounder. 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 sub-bottom profiler 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 sub-bottom profiler is 
usually operated simultaneously with other higher-power acoustic 
sources, including airguns. 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 sub-bottom 
profiler.

[[Page 17372]]

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 in 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 
(especially low frequency specialists) 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' reaction varied when exposed to vessel noise and 
traffic. In some cases, beluga whales exhibited rapid swimming from 
ice-breaking vessels up to 80 km (43.2 nmi) 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; fin whales changed from mostly negative (e.g., avoidance) to 
uninterested reactions; right whales apparently continued the same 
variety of responses (negative, uninterested, and positive responses) 
with little change; and humpbacks dramatically changed from mixed 
responses that were often negative to reactions that were often 
strongly positive. Watkins (1986) summarized that ``whales near shore, 
even in regions with low vessel traffic, generally have become less 
wary of boats and their noises, and they have appeared to be less 
easily disturbed than previously. In particular locations with intense 
shipping and repeated approaches by boats (such as the whale-watching 
areas of Stellwagen Bank), more and more whales had positive reactions 
to familiar vessels, and they also occasionally approached other boats 
and yachts in the same ways.''
    Although the radiated sound from the Langseth and support vessels 
will be audible to marine mammals over a large distance, it is unlikely 
that marine mammals will respond behaviorally (in a manner that NMFS 
would consider harassment under the MMPA) 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 13 kts (24.1 km/hr, 14.9 mph).

[[Page 17373]]

    L-DEO's proposed operation of one source vessel and a support 
vessel for the proposed survey is relatively small in scale compared to 
the number of commercial ships transiting at higher speeds in the same 
area on an annual basis. The probability of vessel and marine mammal 
interactions occurring during the proposed survey is unlikely due to 
the Langseth's and Poseidon's slow operational speed, which is 
typically 4.6 kts (8.5 km/hr, 5.3 mph). Outside of seismic operations, 
the Langseth's cruising speed would be approximately 10 kts (18.5 km/
hr, 11.5 mph), 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; PSOs posted during 
operations scan the ocean for marine mammals and must report visual 
alerts of marine mammal presence to crew; and the PSOs receive 
extensive training that covers the fundamentals of visual observing for 
marine mammals and information about marine mammals and their 
identification at sea.

Entanglement

    Entanglement can occur if wildlife becomes immobilized in survey 
lines, cables, nets, or other equipment that is moving through the 
water column. The proposed seismic survey would require towing 
approximately 6.4 km\2\ (1.9 nmi\2\) of equipment and cables. This 
large of an array carries the risk of entanglement for marine mammals. 
Wildlife, especially slow moving individuals, such as large whales, 
have a low probability of becoming entangled due to slow speed of the 
survey vessel and onboard monitoring efforts. The NSF has no recorded 
cases of entanglement of marine mammals during any of their 160,934 km 
(86,897.4 nmi) of seismic surveys. In May, 2011, there was one recorded 
entanglement of an olive ridley sea turtle (Lepidochelys olivacea) in 
the Langseth's barovanes after the conclusion of a seismic survey off 
Costa Rica. There have cases of baleen whales, mostly gray whales 
(Heyning, 1990), becoming entangled in fishing lines. The probability 
for entanglement of marine mammals is considered not significant 
because of the vessel speed and the monitoring efforts onboard the 
survey vessel.
    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 
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 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 in any particular area of the approximately 6,437 km\2\ 
proposed project area, 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 and 
invertebrate populations is limited. There are three types of potential 
effects of exposure to seismic surveys: (1) Pathological, (2) 
physiological, and (3) behavioral. Pathological effects involve lethal 
and temporary or permanent sub-lethal injury. Physiological effects 
involve temporary and permanent primary and secondary stress responses, 
such as changes in levels of enzymes and proteins. Behavioral effects 
refer to temporary and (if they occur) permanent changes in exhibited 
behavior (e.g., startle and avoidance behavior). The three categories 
are interrelated in complex ways. For example, it is possible that 
certain physiological and behavioral changes could potentially lead to 
an ultimate pathological effect on individuals (i.e., mortality).
    The specific received sound levels at which permanent adverse 
effects to fish potentially could occur are little studied and largely 
unknown. Furthermore, the available information on the impacts of 
seismic surveys on marine fish is from studies of individuals or 
portions of a population; there have been no studies at the population 
scale. The studies of individual fish have often been on caged fish 
that were exposed to airgun pulses in situations not representative of 
an actual seismic survey. Thus, available information provides limited 
insight on possible real-world effects at the ocean or population 
scale. This makes drawing conclusions about impacts on fish problematic 
because, ultimately, the most important issues concern effects on 
marine fish populations, their viability, and their availability to 
fisheries.
    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 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. 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

[[Page 17374]]

scientific literature. As far as L-DEO and NMFS 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 nine 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).
    An experiment of the effects of a single 700 in\3\ airgun was 
conducted in Lake Meade, Nevada (USGS, 1999). The data were used in an 
Environmental Assessment of the effects of a marine reflection survey 
of the Lake Meade fault system by the National Park Service (Paulson et 
al., 1993, in USGS, 1999). The airgun was suspended 3.5 m (11.5 ft) 
above a school of threadfin shad in Lake Meade and was fired three 
successive times at a 30 second interval. Neither surface inspection 
nor diver observations of the water column and bottom found any dead 
fish.
    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.
    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.
    The Minerals Management Service (MMS, 2005) assessed the effects of 
a proposed seismic survey in Cook Inlet. The seismic survey proposed 
using three vessels, each towing two, four-airgun arrays ranging from 
1,500 to 2,500 in\3\. MMS noted that the impact to fish populations in 
the survey area and adjacent waters would likely be very low and 
temporary. MMS also concluded that seismic surveys may displace the 
pelagic fishes from the area temporarily when airguns are in use. 
However, fishes displaced and avoiding the airgun noise are likely to 
backfill the survey area in minutes to hours after cessation of seismic 
testing. Fishes not dispersing from the airgun noise (e.g., demersal 
species) may startle and move short distances to avoid airgun 
emissions.
    In general, any adverse effects on fish behavior or fisheries 
attributable to seismic testing may depend on the species in question 
and the nature of the fishery (season, duration, fishing method). They 
may also depend on the age of the fish, its motivational state, its 
size, and numerous other factors that are difficult, if not impossible, 
to quantify at this point, given such limited data on effects of 
airguns on fish, particularly under realistic at-sea conditions.

Anticipated Effects on Invertebrates

    The existing body of information on the impacts of seismic survey 
sound on marine invertebrates is very limited. However, there is some 
unpublished and very limited evidence of the potential for adverse 
effects on invertebrates, thereby justifying further discussion and 
analysis of this issue. The three types of potential effects of 
exposure to seismic surveys on marine invertebrates are pathological, 
physiological, and behavioral. Based on the physical structure of their 
sensory organs, marine invertebrates appear to be specialized to 
respond to particle displacement components of an impinging sound field 
and not to the pressure component (Popper et al., 2001).
    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

[[Page 17375]]

survey sound ultimately affects invertebrate populations and their 
viability, including availability to fisheries.
    Literature reviews of the effects of seismic and other underwater 
sound on invertebrates were provided by Moriyasu et al. (2004) and 
Payne et al. (2008). The following sections provide a synopsis of 
available information on the effects of exposure to seismic survey 
sound on species of decapod crustaceans and cephalopods, the two 
taxonomic groups of invertebrates on which most such studies have been 
conducted. The available information is from studies with variable 
degrees of scientific soundness and from anecdotal information. A more 
detailed review of the literature on the effects of seismic survey 
sound on invertebrates is provided in Appendix D of the NSF/USGS PEIS.
    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. Tenera 
Environmental (2011b) reported that Norris and Mohl (1983, summarized 
in Mariyasu et al., 2004) observed lethal effects in squid (Loligo 
vulgaris) at levels of 246 to 252 dB after 3 to 11 minutes.
    Andre et al. (2011) exposed four species of cephalopods (Loligo 
vulgaris, Sepia officinalis, Octopus vulgaris, and Ilex coindetii), 
primarily cuttlefish, to two hours of continuous 50 to 400 Hz 
sinusoidal wave sweeps at 1575 dB re 1 [mu]Pa while captive 
in relatively small tanks. They reported morphological and 
ultrastructural evidence of massive acoustic trauma (i.e., permanent 
and substantial alterations [lesions] of statocyst sensory hair cells) 
to 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 1575 dB re 1 [mu]Pa, with peak 
levels at 175 dB re 1 [mu]Pa. 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). It was 
noted however, than no behavioral impacts were exhibited by crustaceans 
(Christian et al., 2003, 2004; DFO, 2004). 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 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 reviewed the following source documents and have 
incorporated a suite of appropriate mitigation measures into their 
project description.
    (1) Protocols used during previous NSF and USGS-funded seismic 
research cruises as approved by NMFS and detailed in the recently 
completed ``Final Programmatic Environmental Impact Statement/Overseas 
Environmental Impact Statement for Marine Seismic Research Funded by 
the National Science Foundation or Conducted by the U.S. Geological 
Survey;''
    (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 have 
proposed to implement the following mitigation measures for marine 
mammals:
    (1) Planning Phase;
    (2) Proposed exclusion zones around the airgun(s);
    (3) Power-down procedures;
    (4) Shut-down procedures;
    (5) Ramp-up procedures; and
    (6) Special procedures for situations or species of concern.

[[Page 17376]]

    Planning Phase--Mitigation of potential impacts from the proposed 
activities begins during the planning phases of the proposed 
activities. Part of the considerations was whether thy research 
objectives could be met with a smaller source than the full, 36-airgun 
array (6,600 in\3\) used on the Langseth, and it was decided that the 
scientific objectives could be met using two 18-airgun arrays, 
operating in ``flip-flop'' mode, and towed at a depth of approximately 
9 m. Thus, the source volume would not exceed 3,300 in\3\ at any time. 
The PIs worked with L-DEO and NSF to identify potential time periods to 
carry out the survey taking into consideration key factors such as 
environmental conditions (i.e., the seasonal presence of marine mammals 
and other protected species), weather conditions, equipment, and 
optimal timing for other proposed seismic surveys using the Langseth. 
Most marine mammal species are expected to occur in the area year-
round, so altering the timing of the proposed project likely would 
result in no net benefits for those species.
    Proposed Exclusion Zones--L-DEO use radii to designate exclusion 
and buffer zones and to estimate take for marine mammals. Table 1 
(presented earlier in this document) shows the distances at which one 
would expect marine mammal exposures to received sound levels (160 and 
180/190 dB) from the 18 airgun array and a single airgun. (The 180 dB 
and 190 dB level shut-down criteria are applicable to cetaceans and 
pinnipeds, respectively, as specified by NMFS [2000].) L-DEO used these 
levels to establish the exclusion and buffer zones.
    If the PSVO detects marine mammal(s) within or about to enter the 
appropriate exclusion zone, the Langseth crew will immediately power-
down the airgun array, or perform a shut-down if necessary (see ``Shut-
down Procedures''). Table 1 summarizes the calculated distances at 
which sound levels (160 and 180 dB [rms]) are expected to be received 
from the 18 airgun array operating in and the single airgun operating 
in deep water depths. Received sound levels have been calculated by L-
DEO, in relation to distance and direction from the airguns, for the 18 
airgun array and for the single 1900LL 40 in\3\ airgun, which will be 
used during power-downs.
    If the PSVO detects marine mammal(s) within or about to enter the 
appropriate exclusion zone, the airguns will be powered-down (or shut-
down, if necessary) immediately.
    Power-down Procedures--A power-down involves decreasing the number 
of airguns in use to one airgun, such that the radius of the 180 dB 
zone is decreased to the extent that the observed marine mammal(s) are 
no longer in or about to enter the exclusion zone for the full airgun 
array. A power-down of the airgun array can also occur when the vessel 
is moving from the end of one seismic trackline to the start of the 
next trackline. During a power-down for mitigation, L-DEO will operate 
one airgun. The continued operation of one airgun is intended to (a) 
alert marine mammals to the presence of the seismic vessel in the area; 
and, (b) retain the option of initiating a ramp-up to full operations 
under poor visibility conditions. In contrast, a shut-down occurs when 
all airgun activity is suspended.
    If the PSVO detects a marine mammal outside the exclusion zone and 
is likely to enter the exclusion zone, L-DEO will power-down the 
airguns to reduce the size of the 180 dB exclusion zone before the 
animal is within the exclusion zone. Likewise, if a mammal is already 
within the exclusion zone, when first detected L-DEO will power-down 
the airguns immediately. During a power-down of the airgun array, L-DEO 
will operate the single 40 in\3\ airgun, which has a smaller exclusion 
zone. If the PSVO detects a marine mammal within or near the smaller 
exclusion zone around that single airgun (see Table 1), L-DEO will 
shut-down the airgun (see next section).
    Resuming Airgun Operations After a Power-down--Following a power-
down, the Langseth will not resume full airgun activity until the 
marine mammal has cleared the 180 or 190 dB exclusion zone (see Table 
1). The PSO will consider the animal to have cleared the exclusion zone 
if:
     The observer has visually observed the animal leave the 
exclusion zone, or
     An observer has not sighted the animal within the 
exclusion zone for 15 minutes for species with shorter dive durations 
(i.e., small odontocetes or pinnipeds), or 30 minutes for species with 
longer dive durations (i.e., mysticetes and large odontocetes, 
including sperm, pygmy sperm, dwarf sperm, and beaked whales); or
     The vessel has transited outside the original 180 dB 
exclusion zone after an 8 minute period minute wait period.
    The Langseth crew will resume operating the airguns at full power 
after 15 minutes of sighting any species with short dive durations 
(i.e., small odontocetes or pinnipeds). Likewise, the crew will resume 
airgun operations at full power after 30 minutes of sighting any 
species with longer dive durations (i.e., mysticetes and large 
odontocetes, including sperm, pygmy sperm, dwarf sperm, and beaked 
whales).
    Because the vessel has transited away from the vicinity of the 
original sighting during the 8 minute period, implementing ramp-up 
procedures for the full array after an extended power-down (i.e., 
transiting for an additional 35 minutes from the location of initial 
sighting) would not meaningfully increase the effectiveness of 
observing marine mammals approaching or entering the exclusion zone for 
the full source level and would not further minimize the potential for 
take. The Langseth's PSOs are continually monitoring the exclusion zone 
for the full source level while the mitigation airgun is firing. On 
average, PSOs can observe to the horizon (10 km or 5.4 nmi) from the 
height of the Langseth's observation deck and should be able to state 
with a reasonable degree of confidence whether a marine mammal would be 
encountered within this distance before resuming airgun operations at 
full power.
    Shut-down Procedures--L-DEO will shut-down the operating airgun(s) 
if a marine mammal is seen within or approaching the exclusion zone for 
the single airgun. L-DEO will implement a shut-down:
    (1) If an animal enters the exclusion zone of the single airgun 
after L-DEO has initiated a power-down; or
    (2) If an animal is initially seen within the exclusion zone of the 
single airgun when more than one airgun (typically the full airgun 
array) is operating (and it is not practical or adequate to reduce 
exposure to less than 180 dB [rms]).
    Considering the conservation status for the North Atlantic right 
whale, the airguns will be shut-down immediately in the unlikely event 
that this species is observed, regardless of the distance from the 
Langseth. Ramp-up will only begin if the North Atlantic right whale has 
not been seen for 30 minutes.
    Resuming Airgun Operations After a Shut-down--Following a shut-down 
in excess of 8 minutes, the Langseth crew will initiate a ramp-up with 
the smallest airgun in the array (40 in\3\). The crew will turn on 
additional airguns in a sequence such that the source level of the 
array will increase in steps not exceeding 6 dB per five-minute period 
over a total duration of approximately 30 minutes. During ramp-up, the 
PSOs will monitor the exclusion zone, and if he/she sights a marine 
mammal, the Langseth crew will implement a power-down or shut-down as 
though the full airgun array were operational.
    During periods of active seismic operations, there are occasions 
when the Langseth crew will need to temporarily

[[Page 17377]]

shut-down the airguns due to equipment failure or for maintenance. In 
this case, if the airguns are inactive longer than eight minutes, the 
crew will follow ramp-up procedures for a shut-down described earlier 
and the PSOs will monitor the full exclusion zone and will implement a 
power-down or shut-down if necessary.
    If the full exclusion zone is not visible to the PSO for at least 
30 minutes prior to the start of operations in either daylight or 
nighttime, the Langseth crew will not commence ramp-up unless at least 
one airgun (40 in\3\ or similar) has been operating during the 
interruption of seismic survey operations. Given these provisions, it 
is likely that the vessel's crew will not ramp-up the airgun array from 
a complete shut-down at night or in thick fog, because the outer part 
of the zone for that array will not be visible during those conditions.
    If one airgun has operated during a power-down period, ramp-up to 
full power will be permissible at night or in poor visibility, on the 
assumption that marine mammals will be alerted to the approaching 
seismic vessel by the sounds from the single airgun and could move 
away. The vessel's crew will not initiate ramp-up of the airguns if a 
marine mammal is sighted within or near the applicable exclusion zones 
during the day or close to the vessel at night.
    Ramp-up Procedures--Ramp-up of an airgun array provides a gradual 
increase in sound levels, and involves a step-wise increase in the 
number and total volume of airguns firing until the full volume of the 
airgun array is achieved. The purpose of a ramp-up is to ``warn'' 
marine mammals in the vicinity of the airguns, and to provide the time 
for them to leave the area and thus avoid any potential injury or 
impairment of their hearing abilities. L-DEO will follow a ramp-up 
procedure when the airgun array begins operating after an 8 minute 
period without airgun operations or when a power-down or shut down has 
exceeded that period. L-DEO has used similar periods (approximately 8 
to 10 min) during previous L-DEO surveys.
    Ramp-up will begin with the smallest airgun in the array (40 
in\3\). Airguns will be added in a sequence such that the source level 
of the array will increase in steps not exceeding six dB per five 
minute period over a total duration of approximately 35 minutes. During 
ramp-up, the PSOs will monitor the exclusion zone, and if marine 
mammals are sighted, L-DEO will implement a power-down or shut-down as 
though the full airgun array were operational.
    If the complete exclusion zone has not been visible for at least 30 
minutes prior to the start of operations in either daylight or 
nighttime, L-DEO will not commence the ramp-up unless at least one 
airgun (40 in\3\ or similar) has been operating during the interruption 
of seismic survey operations. Given these provisions, it is likely that 
the airgun array will not be ramped-up from a complete shut-down at 
night or in thick fog, because the outer part of the exclusion zone for 
that array will not be visible during those conditions. If one airgun 
has operated during a power-down period, ramp-up to full power will be 
permissible at night or in poor visibility, on the assumption that 
marine mammals will be alerted to the approaching seismic vessel by the 
sounds from the single airgun and could move away. L-DEO will not 
initiate a ramp-up of the airguns if a marine mammal is sighted within 
or near the applicable exclusion zones.

Use of a Small-Volume Airgun During Turns and Maintenance

    Throughout the seismic survey, particularly during turning 
movements, and short-duration equipment maintenance activities, L-DEO 
will employ the use of a small-volume airgun (i.e., 40 in\3\ 
``mitigation airgun'') to deter marine mammals from being within the 
immediate area of the seismic operations. The mitigation airgun would 
be operated at approximately one shot per minute and would not be 
operated for longer than three hours in duration (turns may last two to 
three hours for the proposed project).
    During turns or brief transits (e.g., less than three hours) 
between seismic tracklines, one mitigation airgun will continue 
operating. The ramp-up procedure will still be followed when increasing 
the source levels from one airgun to the full airgun array. However, 
keeping one airgun firing will avoid the prohibition of a ``cold 
start'' during darkness or other periods of poor visibility. Through 
use of this approach, seismic operations may resume without the 30 
minute observation period of the full exclusion zone required for a 
``cold start,'' and without ramp-up if operating with the mitigation 
airgun for under 8 minutes, or with ramp-up if operating with the 
mitigation airgun over 8 minutes. PSOs will be on duty whenever the 
airguns are firing during daylight, during the 30 minute periods prior 
to ramp-ups.
    Special Procedures for Situations or Species of Concern--It is 
unlikely that a North Atlantic right whale would be encountered, but if 
so, the airguns will be shut-down immediately if one is sighted at any 
distance from the vessel because of its rarity and conservation status. 
The airgun array shall not resume firing until 30 minutes after the 
last documented whale visual sighting. Concentrations of humpback, sei, 
fin, blue, and/or sperm whales will be avoided if possible (i.e., 
exposing concentrations of animals to 160 dB), and the array will be 
powered-down if necessary. For purposes of this proposed survey, a 
concentration or group of whales will consist of three or more 
individuals visually sighted that do not appear to be traveling (e.g., 
feeding, socializing, etc.).
    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.

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. The monitoring 
work described here has

[[Page 17378]]

been planned as a self-contained project independent of any other 
related monitoring projects that may be occurring simultaneously in the 
same region. L-DEO is prepared to discuss coordination of their 
monitoring program with any related work that might be done by other 
groups insofar as this is practical and desirable.

Vessel-Based Visual Monitoring

    PSVOs will be based aboard the seismic source vessel and will watch 
for marine mammals near the vessel during daytime airgun operations and 
during any ramp-ups of the airguns at night. PSVOs will also watch for 
marine mammals near the seismic vessel for at least 30 minutes prior to 
the start of airgun operations after an extended shut-down (i.e., 
greater than approximately 8 minutes for this proposed cruise). When 
feasible, PSVOs will conduct observations during daytime periods when 
the seismic system is not operating (such as during transits) for 
comparison of sighting rates and behavior with and without airgun 
operations and between acquisition periods. Based on PSVO observations, 
the airguns will be powered-down or shut-down when marine mammals are 
observed within or about to enter a designated exclusion zone.
    During seismic operations in the northeast Atlantic Ocean off of 
Spain, at least five PSOs (four PSVOs and one PSAO) will be based 
aboard the Langseth. L-DEO will appoint the PSOs with NMFS's 
concurrence. Observations will take place during ongoing daytime 
operations and nighttime ramp-ups of the airguns. During the majority 
of seismic operations, two PSVOs will be on duty from the observation 
tower (i.e., the best available vantage point on the source vessel) to 
monitor marine mammals near the seismic vessel. Use of two simultaneous 
PSVOs will increase the effectiveness of detecting animals near the 
source vessel. However, during meal times and bathroom breaks, it is 
sometimes difficult to have two PSVOs on effort, but at least one PSVO 
will be on duty. PSVO(s) will be on duty in shifts no longer than 4 
hours in duration.
    Two PSVOs will also be on visual watch during all daytime ramp-ups 
of the seismic airguns. A third PSAO will monitor the PAM equipment 24 
hours a day to detect vocalizing marine mammals present in the action 
area. In summary, a typical daytime cruise would have scheduled two 
PSVOs on duty from the observation tower, and a third PSAO on PAM. 
Other crew will also be instructed to assist in detecting marine 
mammals and implementing mitigation requirements (if practical). Before 
the start of the seismic survey, the crew will be given additional 
instruction on how to do so.
    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 PSVO will have 
a good view around the entire vessel. During daytime, the PSVO(s) 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 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 marine mammals are detected within or about to enter the 
designated exclusion zone, the airguns will immediately be powered-down 
or shut-down if necessary. The PSVO(s) will continue to maintain watch 
to determine when the animal(s) are outside the exclusion zone by 
visual confirmation. Airgun operations will not resume until the animal 
is confirmed to have left the exclusion zone, or if not observed after 
15 minutes for species with shorter dive durations (small odontocetes 
and pinnipeds) or 30 minutes for species with longer dive durations 
(mysticetes and large odontocetes, including sperm, pygmy sperm, dwarf 
sperm, killer, and beaked whales).

Vessel-Based Passive Acoustic Monitoring

    Vessel-based, towed PAM will complement the visual monitoring 
program, when practicable. Visual monitoring typically is not effective 
during periods of poor visibility or at night, and even with good 
visibility, is unable to detect marine mammals when they are below the 
surface or beyond visual range. PAM can be used in addition to visual 
observations to improve detection, identification, and localization of 
cetaceans. The PAM will serve to alert visual observers (if on duty) 
when vocalizing cetaceans are detected. It is only useful when marine 
mammals call, but it does not depend on good visibility. It will be 
monitored in real time so that the PSVOs can be advised when cetaceans 
are detected.
    The PAM system consists of hardware (i.e., hydrophones) and 
software. The ``wet end'' of the system consists of a towed hydrophone 
array that is connected to the vessel by a tow cable. The tow cable is 
250 m (820.2 ft) long, and the hydrophones are fitted in the last 10 m 
(32.8 ft) of cable. A depth gauge is attached to the free end of the 
cable, and the cable is typically towed at depths less than 20 m (65.6 
ft). The array will be deployed from a winch located on the back deck. 
A deck cable will connect from the winch to the main computer 
laboratory where the acoustic station, signal conditioning, and 
processing system will be located. The acoustic signals received by the 
hydrophones are amplified, digitized, and then processed by the 
Pamguard software. The system can detect marine mammal vocalizations at 
frequencies up to 250 kHz.
    One PSAO, an expert bioacoustician (in addition to the four PSVOs) 
with primary responsibility for PAM, will be onboard the Langseth. The 
towed hydrophones will ideally be monitored by the PSAO 24 hours per 
day while at the proposed seismic survey area during airgun operations, 
and during most periods when the Langseth is underway while the airguns 
are not operating. However, PAM may not be possible if damage occurs to 
the array or back-up systems during operations. The primary PAM 
streamer on the Langseth is a digital hydrophone streamer. Should the 
digital streamer fail, back-up systems should include an analog spare 
streamer and a hull-mounted hydrophone. One PSAO will monitor the 
acoustic detection system by listening to the signals from two channels 
via headphones and/or speakers and watching the real-time 
spectrographic display for frequency ranges produced by cetaceans. The 
PSAO monitoring the acoustical data will be on shift for one to six 
hours at a time. All PSOs are expected to rotate through the PAM 
position, although the expert PSAO (most experienced) will be on PAM 
duty more frequently.
    When a vocalization is detected while visual observations (during 
daylight) are in progress, the PSAO will contact the PSVO immediately, 
to alert him/her to the presence of cetaceans (if they have not already 
been seen), and to allow a power-down or shut-down to be initiated, if 
required. When bearings (primary and mirror-image) to calling 
cetacean(s) are determined, the bearings will be relayed to the PSVO(s) 
to help him/her sight the calling animal. During non-daylight hours, 
when a cetacean is detected by acoustic monitoring and may be close to 
the source vessel, the

[[Page 17379]]

Langseth crew will be notified immediately so that the proper 
mitigation measure may be implemented.
    The information regarding the call will be entered into a database. 
Data entry will include an acoustic encounter identification number, 
whether it was linked with a visual sighting, date, time when first and 
last heard and whenever any additional information was recorded, 
position and water depth when first detected, bearing if determinable, 
species or species group (e.g., unidentified dolphin, sperm whale), 
types and nature of sounds heard (e.g., clicks, continuous, sporadic, 
whistles, creaks, burst pulses, strength of signal, etc.), and any 
other notable information. The acoustic detection can also be recorded 
for further analysis.

PSO Data and Documentation

    PSVOs will record data to estimate the numbers of marine mammals 
exposed to various received sound levels and to document apparent 
disturbance reactions or lack thereof. Data will be used to estimate 
numbers of animals potentially `taken' by harassment. They will also 
provide information needed to order a power-down or shut-down of the 
airguns when a marine mammal is within or near the exclusion zone. 
Observations will also be made during daytime periods when the Langseth 
is underway without seismic operations. There will also be 
opportunities to collect baseline biological data during the transits 
to, from, and through the study area.
    When a sighting is made, the following information about the 
sighting will be recorded:
    1. Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from seismic vessel, sighting cue, 
apparent reaction to the airguns or vessel (e.g., none, avoidance, 
approach, paralleling, etc.), and behavioral pace.
    2. Time, location, heading, speed, activity of the vessel, sea 
state, visibility, and sun glare.
    The data listed under (2) will also be recorded at the start and 
end of each observation watch, and during a watch whenever there is a 
change in one or more of the variables.
    All observations and ramp-ups, power-downs, or shut-downs will be 
recorded in a standardized format. The PSOs will record this 
information onto datasheets. During periods between watches and periods 
when operations are suspended, those data will be entered into a laptop 
computer running a custom computer database. The accuracy of the data 
entry will be verified by computerized data validity checks as the data 
are entered and by subsequent manual checking of the database. These 
procedures will allow initial summaries of data to be prepared during 
and shortly after the field program, and will facilitate transfer of 
the data to statistical, graphical, and other programs for further 
processing and archiving.
    Results from the vessel-based observations will provide:
    1. The basis for real-time mitigation (airgun power-down or shut-
down).
    2. Information needed to estimate the number of marine mammals 
potentially taken by harassment, which must be reported to NMFS.
    3. Data on the occurrence, distribution, and activities of marine 
mammals 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 comprehensive 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 (i.e., dates, times, locations, 
activities, associated seismic survey activities, and associated PAM 
detections). The report will minimally include:
     Summaries of monitoring effort--total hours, total 
distances, and distribution of marine mammals through the study period 
accounting for Beaufort sea state and other factors affecting 
visibility and detectability of marine mammals;
     Analyses of the effects of various factors influencing 
detectability of marine mammals including Beaufort sea state, number of 
PSOs, and fog/glare;
     Species composition, occurrence, and distribution of 
marine mammals sightings including date, water depth, numbers, age/
size/gender, and group sizes; and analyses of the effects of seismic 
operations;
     Sighting rates of marine mammals during periods with and 
without airgun activities (and other variables that could affect 
detectability);
     Initial sighting distances versus airgun activity state;
     Closest point of approach versus airgun activity state;
     Observed behaviors and types of movements versus airgun 
activity state;
     Numbers of sightings/individuals seen versus airgun 
activity state; and
     Distribution around the source vessel versus airgun 
activity state.

The report will also include estimates of the number and nature of 
exposures that could result in ``takes'' of marine mammals by 
harassment or in other ways. After the report is considered final, it 
will be publicly available on the NMFS and NSF Web sites at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#iha and https://www.nsf.gov/geo/oce/encomp/index.jsp.
    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner not permitted by the 
authorization (if issued), such as an injury, serious injury, or 
mortality (e.g., ship-strike, gear interaction, and/or entanglement), 
the L-DEO shall immediately cease the specified activities and 
immediately report the incident to the Incidental Take Program 
Supervisor, Permits and Conservation Division, Office of Protected 
Resources, NMFS, at 301-427-8401 and/or by email to 
Jolie.Harrison@noaa.gov and Howard.Goldstein@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 used 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 animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    L-DEO shall not resume its activities until NMFS is able to review 
the circumstances of the prohibited take. NMFS shall work with L-DEO to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. The 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

[[Page 17380]]

the lead PSO 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 NMFS describes in the next 
paragraph), the L-DEO will immediately report the incident to the 
Incidental Take Program Supervisor, Permits and Conservation Division, 
Office of Protected Resources, at 301-427-8401 and/or by email to 
Jolie.Harrison@noaa.gov and Howard.Goldstein@noaa.gov. The report must 
include the same information identified in the paragraph above this 
section. Activities may continue while NMFS reviews the circumstances 
of the incident. NMFS will work with the 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 the lead PSO determines that the injury or death is not associated 
with or related to the authorized activities (e.g., previously wounded 
animal, carcass with moderate to advanced decomposition, or scavenger 
damage), the L-DEO would report the incident to the Incidental Take 
Program Supervisor, Permits and Conservation Division, Office or 
Protected Resources, at 301-427-8401 and/or by email to 
Jolie.Harrison@noaa.gov and Howard.Goldstein@noaa.gov, within 24 hours 
of the discovery. The L-DEO would provide photographs or video footage 
(if available) or other documentation of the stranded animal sighting 
to NMFS.

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].
    Level B harassment is anticipated and proposed to be authorized as 
a result of the proposed marine seismic survey in the northeast 
Atlantic Ocean. Acoustic stimuli (i.e., increased underwater sound) 
generated during the operation of the seismic airgun array are expected 
to result in the behavioral disturbance of some marine mammals. There 
is no evidence that the planned activities could result in injury, 
serious injury, or mortality 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 in the northeast Atlantic Ocean. The estimates are 
based on a consideration of the number of marine mammals that could be 
harassed by seismic operations with the 18 airgun array to be used. The 
size of the proposed 2D and 3D seismic survey area in 2013 is 
approximately 5,834 km (3,150.1 nmi), as depicted in Figure 1 of the 
IHA application.
    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 multibeam echosounder and sub-bottom profiler 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 multibeam echosounder and sub-bottom profiler 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 provided no 
additional allowance for animals that could be affected by sound 
sources other than airguns.
    L-DEO used densities presented in the CODA final report for surveys 
off northwest Spain in 2007 (Anonymous, 2009; Macleod et al., 2009) to 
estimate how many animals could be exposed during the proposed survey. 
The density reported for ``unidentified large whale'' was allocated to 
the humpback whale because there are a number of sightings of humpback 
whales off northwest Spain, although it wasn't sighted in the CODA 
surveys and most other large whales were. Macleod et al. (2008) didn't 
provide densities for beaked whale species, only ``beaked whales,'' 
therefore the density for beaked whales was allocated to Cuvier's 
beaked whale, as this was the most numerous species of beaked whale 
sighted during surveys off northwest Spain (see Basto d'Anstrade, 
2008). Also, the CODA report (Anonymous, 2008) discussed two predicted 
high-density areas for beaked whales, in the most north-westerly 
section (Sowerby's beaked whale and northern bottlenose whale) and the 
most south-easterly section, the Gulf of Biscay (Cuvier's beaked 
whale). Except for beaked whales and bottlenose dolphins, all reported 
densities were corrected for trackline detection probability 
([fnof][0]) and availability (g[0]) biases by the authors of the CODA 
report. L-DEO chose not to correct the other densities, [fnof](0) and 
g(0) are specific to the location and cetacean habitat. Although there 
is some uncertainty about the representativeness of the data and 
assumptions used in the calculations below, the approach used here is 
believed to be the best available approach. The CODA surveys were in 
July, 2007 (versus June to mid-July, 2013 for the proposed seismic 
survey), and CODA survey block 3, the closest to the proposed offshore 
survey area, includes waters closer to shore and is somewhat farther 
north (43 to 45[deg] versus 42[deg] North) and extends west to the 
north of Spain towards the Bay of Biscay.
    The estimated numbers of individuals potentially exposed presented 
below are based on the 160 dB (rms) criterion currently used for all 
cetaceans. It is assumed that marine mammals exposed to airgun sounds 
that strong could change their behavior sufficiently to be considered 
``taken by harassment.'' Table 3 shows the density estimates calculated 
as described above and the estimates of the number of different 
individual marine mammals that potentially could be exposed to greater 
than or equal to 160 dB (rms) during the seismic survey if no animals 
moved away from the survey vessel. The requested take authorization is 
given in the far right column of Table 3. For species for which 
densities were not calculated as described above, but for which there 
were Ocean Biogeographic Information System (OBIS) sightings around the 
Azores, L-DEO has included a requested take authorization for the mean 
group size for the species.
    It should be noted that the following estimates of exposures to 
various sound levels assume that the proposed survey would be 
completed; in fact, the esonified areas calculated using the planned 
number of line-kilometers have been increased by 25% to accommodate 
turns, lines that may need to be repeated, equipment testing, etc. As 
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. 
Also, any marine mammal sightings within or near the designated 
exclusion zones would result in shut-down of seismic operations as a 
mitigation measure. Thus, the following estimates of the numbers of 
marine mammals potentially exposed to 160 dB

[[Page 17381]]

(rms) sounds are precautionary and probably overestimate the actual 
numbers of marine mammals that could be involved. These estimates 
assume that there would be no weather, equipment, or mitigation delays, 
which is highly unlikely.
    The number of different individuals that could be exposed to airgun 
sounds with received levels greater than or equal to 160 dB (rms) on 
one or more occasions can be estimated by considering the total marine 
area that would be within the 160 dB (rms) radius around the operating 
seismic source on at least one occasion, along with the expected 
density of animals in the area. 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. During 
the proposed survey, the transect lines are closely spaced relative to 
the 160 dB distance. Thus, the area including overlap is 8.2 times the 
area excluding overlap, so a marine mammal that stayed in the survey 
area during the entire survey could be exposed approximately 8 times, 
on average. However, it is unlikely that a particular animal would stay 
in the area during the entire survey. The numbers of different 
individuals potentially exposed to greater than or equal to 160 dB 
(rms) were calculated by multiplying the expected species density times 
the anticipated area to be ensonified to that level during airgun 
operations excluding overlap. 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 zone (see Table 1) around each seismic line, 
and then calculating the total area within the buffer zone.

    Table 3--Estimated Densities of Marine Mammal Species and Estimates of Possible Numbers of Marine Mammals
 Exposed to Sound Levels >=160 dB During L-DEO's Proposed Seismic Survey in the Northeast Atlantic Ocean (in the
                              Deep Galicia Basin West of Spain), June to July, 2013
----------------------------------------------------------------------------------------------------------------
                                                             Calculated take
                                                              authorization
                                                            [i.e., estimated   Requested take      Approximate
                                              Reported/         number of       authorization     percentage of
                                              estimated        individuals     with additional    estimated of
                 Species                  density (/km \2\)     levels >= 160 dB     increase to       population
                                                             re 1 [micro]Pa]     group size)    (requested take)
                                                              (includes 25%                            \1\
                                                              contingency)
----------------------------------------------------------------------------------------------------------------
Mysticetes:
    North Atlantic right whale..........                 0                 0                 0                 0
    Humpback whale......................             0.001                 8                 8       0.07 (0.07)
    Minke whale.........................                 0                 0                 3         0 (<0.01)
    Sei whale...........................             0.002                16                16       0.13 (0.13)
    Fin whale...........................             0.019               153               153       0.62 (0.62)
    Blue whale..........................                 0                 0                 2          0 (0.21)
Odontocetes:
    Sperm whale.........................             0.003                24                24       0.18 (0.18)
    Kogia spp. (Pygmy and dwarf sperm                    0                 0                 0             0 (0)
     whale).............................
    Cuvier's beaked whale...............             0.004                32                32       0.46 (0.46)
    Northern bottlenose whale...........                 0                 0                 4          0 (0.01)
    Mesoplodon spp. (i.e., True's,                       0                 0                 7           0 (0.1)
     Gervais', Sowerby's, and
     Blainville's beaked whale..........
    Bottlenose dolphin..................             0.005                40                40       0.21 (0.21)
    Atlantic spotted dolphin............                 0                 0                 0             0 (0)
    Striped dolphin.....................             0.047               378               378       0.56 (0.56)
    Short-beaked common dolphin.........             0.077               620               620       0.53 (0.53)
    Risso's dolphin.....................                 0                 0                 4          0 (0.02)
    Pygmy killer whale..................                 0                 0                 0           NA (NA)
    False killer whale..................                 0                 0                10           NA (NA)
    Killer whale........................                 0                 0                 5           NA (NA)
    Short-finned pilot whale............                 0                 0                 5         0 (<0.01)
    Long-finned pilot whale.............             0.001                 8                 8    <0.001 (<0.01)
----------------------------------------------------------------------------------------------------------------
NA = Not available or not assessed.
\1\ Stock sizes are best populations from NMFS Stock Assessment Reports (see Table 2 above).
\2\ Requested take authorization was increased to group size for species for which densities were not available
  but that have been sighted near the proposed survey area.

    Applying the approach described above, approximately 6,437 km\2\ 
(1,876.7 nmi\2\) (approximately 8,046 km\2\ [2,345.8 nmi\2\] including 
the 25% contingency) would be within the 160 dB isopleth on one or more 
occasions during the proposed survey. Because this approach does not 
allow for turnover in the marine mammal populations in the area during 
the course of the survey, the actual number of individuals exposed may 
be underestimated, although the conservative (i.e., probably 
overestimated) line-kilometer distances used to calculate the area may 
offset this. Also, the approach assumes that no cetaceans would move 
away or toward the trackline as the Langseth approaches in response to 
increasing sound levels before the levels reach 160 dB (rms). Another 
way of interpreting the estimates that follow is that they represent 
the number of individuals that are expected (in the absence of a 
seismic program) to occur in the waters that would be exposed to 
greater than or equal to 160 dB (rms).
    The estimate of the number of individual cetaceans by species that 
could be exposed to seismic sounds with received levels greater than or 
equal to 160 dB re 1 [mu]Pa (rms) during

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the proposed survey is (with 25% contingency) as follows: 8 humpback, 
16 sei, 153 fin, and 24 sperm, which would represent 0.07, 0.13, 0.61, 
and 0.18% of the affected regional populations, respectively. In 
addition, 43 beaked whales, (including 32 Cuvier's, 4 northern 
bottlenose, and 7 Mesoplodon beaked whales) could be taken by Level B 
harassment during the proposed seismic survey, which would represent 
0.46, 0.01, and 0.1% of the regional populations. Most of the cetaceans 
potentially taken by Level B harassment are delphinids; bottlenose, 
striped, and short-beaked common, dolphins, are estimated to be the 
most common delphinid species in the area, with estimates of 40, 378, 
and 620, which would represent 0.21, 0.56, and 0.53% of the regional 
populations, respectively.

Encouraging and Coordinating Research

    L-DEO and NSF will coordinate the planned marine mammal monitoring 
program associated with the seismic survey with other parties that may 
have interest in this area. L-DEO and NSF will coordinate with 
applicable U.S. agencies (e.g., NMFS), and will comply with their 
requirements.

Negligible Impact and Small Numbers Analyses and Determinations

    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); and
    (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, 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.
    As described above and based on the following factors, the 
specified activities associated with the marine seismic survey are not 
likely to cause PTS, or other non-auditory injury, serious injury, or 
death. The factors include:
    (1) The likelihood that, given sufficient notice through relatively 
slow ship speed, marine mammals are expected to move away from a noise 
source that is annoying prior to its becoming potentially injurious;
    (2) The potential for temporary or permanent hearing impairment is 
relatively low and would likely be avoided through the implementation 
of the power-down and shut-down measures;
    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. Table 3 of this document 
outlines the number of requested Level B harassment takes that are 
anticipated as a result of these activities. Further, the seismic 
surveys will not take place in areas of significance for marine mammal 
feeding, resting, breeding, or calving and will not adversely impact 
marine mammal habitat.
    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 estimated 
duration of the survey would last no more than 39 days. Additionally, 
the seismic survey will be increasing sound levels in the marine 
environment in a relatively small area surrounding the vessel (compared 
to the range of the animals), which is constantly travelling over 
distances, and some animals may only be exposed to and harassed by 
sound for shorter less than day.
    As mentioned previously, NMFS estimates that 20 species of marine 
mammals under its jurisdiction could be potentially affected by Level B 
harassment over the course of the IHA. The population estimates for the 
marine mammal species that may be taken by Level B harassment were 
provided in Table 3 of this document.
    NMFS's 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, the impact of 
conducting a marine seismic survey in the northeast Atlantic Ocean, 
June to July, 2013, may result, at worst, in a modification in behavior 
and/or low-level physiological effects (Level B harassment) of certain 
species of marine mammals.
    While behavioral modifications, including temporarily vacating the 
area during the operation of the airgun(s), may be made by these 
species to avoid the resultant acoustic disturbance, the availability 
of alternate areas within these areas for species and the short and 
sporadic duration of the research activities, have led NMFS to 
preliminary determine that the taking by Level B harassment from the 
specified activity will have a negligible impact on the affected 
species in the specified geographic region. 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 activity is not expected to impact rates of annual 
recruitment or survival for any affected species or stock, particularly 
given the NMFS and the applicant's proposal to implement a mitigation 
and monitoring plans to minimize impacts to marine mammals.
    The requested take estimates represent a small number relative to 
the affected species or stock size (i.e., all are less than 1%). See 
Table 3 for the requested authorized take number of marine mammals.

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

    Section 101(a)(5)(D) of the MMPA 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 (in the northeast Atlantic 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 North Atlantic right, humpback, sei, fin, blue, and sperm whales. 
L-DEO did not request take of endangered North Atlantic right whales 
due to the low

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likelihood of encountering this species during the cruise. 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's Office of 
Protected Resources, Permits and Conservation Division, has initiated 
formal consultation under section 7 of the ESA with NMFS's 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's Biological Opinion issued to 
both NSF and NMFS's Office of Protected Resources.

National Environmental Policy Act

    With L-DEO's complete application, NSF and L-DEO provided NMFS a 
draft ``Environmental Analysis of a Marine Geophysical Survey by the R/
V Marcus G. Langseth in the Northeast Atlantic Ocean, June-July 2013,'' 
prepared by LGL Ltd., Environmental Research Associates, on behalf of 
NSF and L-DEO. The EA analyzes the direct, indirect, and cumulative 
environmental impacts of the proposed specified activities on marine 
mammals including those listed as threatened or endangered under the 
ESA. Prior to making a final decision on the IHA application, NMFS, 
after review and evaluation of the NSF EA for consistency with the 
regulations published by the Council of Environmental Quality (CEQ) and 
NOAA Administrative Order 216-6, Environmental Review Procedures for 
Implementing the National Environmental Policy Act, will prepare an 
independent EA and make a decision of whether or not to issue a Finding 
of No Significant Impact (FONSI).

Proposed Authorization

    NMFS proposes to issue an IHA to L-DEO for conducting a marine 
seismic survey in the northeast Atlantic 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's 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 18, 2013.
Helen M. Golde,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2013-06504 Filed 3-20-13; 8:45 am]
BILLING CODE 3510-22-P