Incidental Takes of Marine Mammals During Specified Activities; Marine Seismic Survey in the Arctic Ocean, August to September, 2010, 39336-39364 [2010-16374]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 75, Number 130 (Thursday, July 8, 2010)]
[Notices]
[Pages 39336-39364]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-16374]



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Part II





Department of Commerce





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National Oceanic and Atmospheric Administration



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Incidental Takes of Marine Mammals During Specified Activities; Marine 
Seismic Survey in the Arctic Ocean, August to September, 2010; Notice

Federal Register / Vol. 75 , No. 130 / Thursday, July 8, 2010 / 
Notices

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XW05


Incidental Takes of Marine Mammals During Specified Activities; 
Marine Seismic Survey in the Arctic Ocean, August to September, 2010

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

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

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SUMMARY: NMFS has received an application from the U.S. Geological 
Survey (USGS) for an Incidental Harassment Authorization (IHA) to take 
small numbers of marine mammals, by harassment, incidental to 
conducting a marine seismic survey in the Arctic Ocean during August to 
September, 2010. Pursuant to the Marine Mammal Protection Act (MMPA), 
NMFS requests comments on its proposal to authorize USGS to 
incidentally take, by Level B harassment only, small numbers of marine 
mammals during the aforementioned activity.

DATES: Comments and information must be received no later than August 
9, 2010.

ADDRESSES: Comments on the application should be addressed to P. 
Michael Payne, Chief, Permits, Conservation, and Education Division, 
Office of Protected Resources, National Marine Fisheries Service, 1315 
East-West Highway, Silver Spring, MD 20910. The mailbox address for 
providing e-mail comments is PR1.0648-XW05@noaa.gov. NMFS is not 
responsible for e-mail comments sent to addresses other than the one 
provided here. Comments sent via e-mail, including all attachments, 
must not exceed a 10-megabyte file size.
    All comments received are a part of the public record and will 
generally be posted to https://www.nmfs.noaa.gov/pr/permits/incidental.htm 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 address specified 
above, telephoning the contact listed below (see FOR FURTHER 
INFORMATION CONTACT), or visiting the Internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm. 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, 301-713-2289.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce (Secretary) to allow, upon request, 
the incidental, but not intentional, taking of marine mammals 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 either regulations are issued or, if the taking 
is limited to harassment, a notice of a proposed authorization is 
provided to the public for review.
    An authorization for incidental taking of small numbers of marine 
mammals shall be granted if NMFS finds that the taking will have a 
negligible impact on the species or stock(s), will not have an 
unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses, and if the permissible methods of taking 
and requirements pertaining to the mitigation, monitoring and reporting 
of such takings are set forth. NMFS has defined ``negligible impact'' 
in 50 CFR 216.103 as ``* * * an impact resulting from the specified 
activity that cannot be reasonably expected to, and is not reasonably 
likely to, adversely affect the species or stock through effects on 
annual rates of recruitment or survival.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the United States can apply for an authorization 
not to exceed one year to incidentally take small numbers of marine 
mammals by 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''].

16 U.S.C. 1362(18)
    Section 101(a)(5)(D) establishes a 45-day time limit for NMFS' 
review of an application followed by a 30-day public notice and comment 
period for any proposed authorizations for the incidental harassment of 
marine mammals. Within 45 days of the close of the comment period, 
NMFS, MMPA must either issue or deny the authorization.

Summary of Request

    On March 9, 2010, NMFS received an IHA application and an 
Environmental Assessment (EA) from USGS for the taking, by Level B 
harassment only, of small numbers of several species of marine mammals 
incidental to conducting a marine seismic survey in the Arctic Ocean 
during August to September, 2010. NMFS received a revised IHA 
application and a revised EA on June 1, 2010.

Description of the Specified Activity

    USGS plans to conduct a marine geophysical (seismic reflection/
refraction) and bathymetric survey in the Arctic Ocean in August and 
September, 2010 (see Tables 1 and 2, and Figure 3 of the IHA 
application). The survey will be conducted from the Canadian Coast 
Guard (CCG) vessel CCGS Louis S. St. Laurent (St. Laurent) which will 
be accompanied by the U.S. Coast Guard Cutter (USCGC) Healy, both of 
which are polar-class icebreakers. Descriptions of the vessels and 
their specifications are presented in Appendix A of the IHA 
application. The two vessels will operate in tandem in the presence of 
ice but may diverge and operate independently in open water. Some minor 
deviation of the dates is possible, depending on logistics and weather 
(i.e., the cruise may depart earlier or be extended due to poor 
weather; there could be extra days of seismic operations if collected 
data are of sub-standard quality).
    One CCG helicopter will be available for deployment from the St. 
Laurent for ice reconnaissance and crew transfers between the vessels 
during survey operations. Helicopters transfer of crew from the Healy 
is also planned for approximately one day during a ship-to-shore crew 
change at Barrow, Alaska at the end of the survey. The helicopter 
operations in Barrow will be conducted under Department of Interior 
(DOI) contract. Daily helicopter operations are anticipated pending 
weather conditions. Spot bathymetry will also be conducted from the 
helicopter outside U.S. waters.
    Acoustic sources onboard the St. Laurent will include an airgun 
array comprised of three Sercel G-airguns and a Knudsen 320BR ``Chirp'' 
pulse echosounder operating at 12 kHz. The St. Laurent will also tow a 
3 to 5 kHz sub-bottom profiler while in open water

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and when not working with the Healy. The airgun array consists of two 
500 in \3\ and one 150 in \3\ airguns for an overall discharge of 1,150 
in \3\. Table 2 of the IHA application presents different sound 
pressure level (SPL) radii of the airgun array. Acoustic sources that 
will be operated on the St. Laurent are described in detail in Section 
VII and Appendix B in the IHA application. The seismic array and a 
hydrophone streamer towed from the St. Laurent will operate under the 
provisions of a Canadian authorization based on Canada's environmental 
assessment of the proposed survey while in Canadian or international 
waters, and under the provisions of an IHA issued to the USGS by NMFS 
in U.S. waters. NMFS cannot issue an IHA directly to a non-U.S. 
citizen, however, the Geological Survey of Canada (GSC) has written a 
Categorical Declaration stating that ``while in U.S. waters (i.e., the 
U.S. 200 mile Exclusive Economic Zone), the GSC will comply with any 
and all environmental mitigation measures required by the U.S. NMFS 
and/or the U.S. Fish and Wildlife Service.'' The St. Laurent will 
follow the lead of the Healy. The Healy will break and clear ice 
approximately 1.6 to 3.2 km (1 to 2 miles [mi]) in advance of the St. 
Laurent. In situations where the array (and hydrophone streamer) cannot 
be towed safely due to ice cover, the St. Laurent may escort the Healy. 
The Healy will use a multi-beam echosounder (Kongsberg EM122), a sub-
bottom profiler (Knudsen 3.5 kHz Chirp), and a ``piloting'' echosounder 
(ODEC 1500) continuously when underway and during the seismic 
profiling. Acoustic Doppler current profilers (75 kHz and 150 kHz) may 
also be used on the Healy. The Healy's acoustic systems are described 
in further detail in Section VII and Appendix B of the IHA application.
    In addition to the hydrophone streamer, marine sonobuoys will be 
deployed to acquire wide angle reflection and refraction data for 
velocity determination to convert seismic reflection travel time to 
depth. Sonobuoys will be deployed off the stern of the St. Laurent 
approximately every eight hours during seismic operations with as many 
as three deployments per day. The sonobuoy's hydrophone will activate 
at a water depth of approximately 60 m (196.9 ft) and seismic signals 
will be communicated via radio to the St. Laurent. The sonobuoys are 
pre-set to scuttle (i.e., deliberately sink) eight hours after 
activation.
    The program within U.S. waters will consist of approximately 806 km 
(500.8 mi) of survey transect line, not including transits when the 
airguns are not operating (see Figure 1 and Table 1 of the IHA 
application). U.S. priorities include another 997 km (619.5 mi) of 
survey lines north of the U.S. Exclusive Economic Zone (EEZ), for a 
total of 1,803 km (1,120.3 mi) of tracklines of interest to the U.S. 
Table 1 of the IHA application lists all U.S. priority tracklines; 
Figure 1 of the IHA application includes all U.S. priority tracks and 
the area of interest to Canada near the proposed U.S. tracklines. Water 
depths within the U.S. study area will range from approximately 1,900 
to 4,000 m (6,233.5 to 13,123.4 ft) (see Figure 1 of the IHA 
application). There may be additional seismic operations associated 
with airgun testing, start-up, and repeat coverage of any areas where 
initial data quality is sub-standard. The tracklines that will be 
surveyed in U.S. waters include the southern 263.8 km (164 mi) of the 
line that runs North-South in the western EEZ, the southern 264.5 km 
(164.4 mi) of the line that runs North-South in the central EEZ, and 
277.7 km (172.6 mi) trackline of the line that connects the two (see 
Figure 1 and Table 1 of the IHA application). The IHA application 
requests the authorization of incidental takes of marine mammals for 
activities within U.S. waters.

     Table 1--Proposed U.S. Priority Tracklines for USGS and Geological Survey of Canada (GSC) 2010 Extended
                     Continental Shelf Survey in the Northern Beaufort Sea and Arctic Ocean
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                                                                                                    Time (hour
           Location               End point 1      End point 2    Kilometer (km)   Nautical Mile  [hr]) @ 4 nmi/
                                                                                       (nmi)            hr
----------------------------------------------------------------------------------------------------------------
NS in central EEZ (south)....  71.22[deg]        72.27[deg]                  118              64              16
                                North;            North;
                                145.17[deg]       145.41[deg]
                                West.             West.
NS in central EEZ (north)....  72.27[deg]        73.92[deg]                  183             100              25
                                North;            North;
                                145.41[deg]       145.30[deg]
                                West.             West.
Central-western EEZ connector  73.92[deg]        71.84[deg]                  317             171              43
                                North;            North;
                                145.30[deg]       151.82[deg]
                                West.             West.
NS in western EEZ............  71.84[deg]        74.32[deg]                  281             152              39
                                North;            North;
                                151.82[deg]       150.30[deg]
                                West.             West.
South Northwind Ridge........  74.32[deg]        74.96[deg]                  239             129              32
                                North;            North;
                                150.30[deg]       158.01[deg]
                                West.             West.
Northwind Ridge connector....  74.96[deg]        76.30[deg]                  161              87              22
                                North;            North;
                                158.01[deg]       155.88[deg]
                                West.             West.
Mid-Northwind Ridge..........  76.30[deg]        75.41[deg]                  274             148              37
                                North;            North;
                                155.88[deg]       146.50[deg]
                                West.             West.
Northwind Ridge connector....  75.41[deg]        76.57[deg]                  129              70              17
                                North;            North;
                                146.50[deg]       146.82[deg]
                                West.             West.
Mid-Northwind Ridge..........  76.57[deg]        76.49[deg]                  102              55              14
                                North;            North;
                                146.82[deg]       150.73[deg]
                                West.             West.
                              ----------------------------------------------------------------------------------
    Totals...................  ................  ...............           1,804             976             245
----------------------------------------------------------------------------------------------------------------

    Two vessels will operate cooperatively during the proposed seismic 
survey. The St. Laurent will conduct seismic operations using an airgun 
array and also operate a 12 kHz Chirp echosounder. The St. Laurent will 
also operate a 3 to 5 kHz sub-bottom profiler in open water when not 
working with the Healy. The Healy will normally escort the St. Laurent 
in ice cover, and will continuously operate a bathymetric multi-beam 
echosounder, a 3.5 kHz Chirp sub-bottom profiler, a piloting 
echosounder, and two acoustic Doppler current profilers.
    The St. Laurent will access the survey area from Canada and 
rendezvous with the Healy on approximately August 7, 2010; the Healy 
will approach the survey area from the Bering Straits. The St. Laurent 
will deploy a relatively small airgun array comprised of three G-
airguns and a single hydrophone streamer approximately 300 m (984 ft) 
in length. The airgun array consists of two 500 in\3\ and one 150 in\3\ 
airguns for an overall discharge of 1,150 in\3\. The St. Laurent will 
follow the lead of the Healy which will operate approximately 1.9 to 
3.8 km (1 to 2 nmi) ahead of the St. Laurent. In ice conditions where 
seismic gear cannot be safely towed, the St. Laurent will escort the 
Healy to optimize multi-beam bathymetry data collection. If extended 
open-water conditions are encountered, Healy and St. Laurent may 
operate independently.
    The U.S. priority survey lines will consist of eight transect lines 
ranging in

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length from approximately 102 to 317 km (63.4 to 197 mi) of trackline 
(see Table 1 and Figure 1 of the IHA application). These tracklines are 
planned in water depths of 1,900 to 4,000 m (6,234 to 13,123 ft). 
Approximately 806 km (500.8 mi) of trackline will be surveyed within 
U.S. waters. The survey line nearest to shore in U.S. waters is 
approximately 116 km (63 nmi) offshore at its closest point. After 
completion of the survey the St. Laurent will return to port in Canada, 
and the Healy will change crew at Barrow via helicopter or surface 
conveyance before continuing on another project.

Vessel Specifications

    The CCGS St. Laurent was built in 1969 by Canadian Vickers Ltd. in 
Montreal, Quebec, and underwent an extensive modernization in Halifax, 
Nova Scotia between 1988 to 1993. The St. Laurent is based at CCG Base 
Dartmouth in Dartmouth, Nova Scotia. Current vessel activities involve 
summer voyages to the Canadian Arctic for sealifts to various coastal 
communities and scientific expeditions. A description of the St. 
Laurent with vessel specifications is presented in Appendix A of the 
IHA application and is available online at: https://www.ccg-gcc.gc.ca/eng/Fleet/Vessels?id=1111&info=5&subinfo.
    The Healy is designed to conduct a wide range of research 
activities, providing more than 390.2 m\2\ (4,200 ft\2\) of scientific 
laboratory space, numerous electronic sensor systems, oceanographic 
winches, and accommodations for up to 50 scientists. The Healy is 
designed to break 1.4 m (4.5 ft) of ice continuously at 5.6 km/hour 
(three knots) and can operate in temperatures as low as -45.6 C (-50 
degrees F). The science community provided invaluable input on lab lay-
outs and science capabilities during design and construction of the 
ship. The Healy is also a capable platform for supporting other 
potential missions in the polar regions, including logistics, search 
and rescue, ship escort, environmental protection, and enforcement of 
laws and treaties.
    The Healy is a USCG icebreaker, capable of traveling at 5.6 km/hour 
(three knots) through 1.4 m (4.5 ft) of ice. A ``Central Power Plant,'' 
four Sultzer 12Z AU40S diesel generators, provides electric power for 
propulsion and ship's services through a 60 Hz, three-phase common bus 
distribution system. Propulsion power is provided by two electric AC 
Synchronous, 11.2 MW drive motors, fed from the common bus through a 
Cycloconverter system, that turn two fixed-pitch, four-bladed 
propellers. The Healy will also serve as the platform from which 
vessel-based Protected Species Observers (PSOs) will watch for marine 
mammals before and during airgun operations. Other details of the Healy 
can be found in Appendix A of the IHA application.
    NMFS believes that the realistic possibility of a ship-strike of a 
marine mammal by the vessel during research operations and in-transit 
during the proposed survey is discountable. The probability of a ship 
strike resulting in an injury or mortality of an animal has been 
associated with ship speed; however, it is highly unlikely that the 
proposed seismic survey would increase the rate of serious injury or 
mortality given the St. Laurent and Healy's slow survey speed.

Acoustic Source Specifications--Seismic Airguns and Radii

    The seismic source for the proposed seismic survey will be 
comprised of three Sercel G-airguns with a total volume of 1,150 in\3\. 
The three-airgun array will be comprised of two 500 in\3\ and one 150 
in\3\ G-airguns in a triangular configuration (see Figure B-1 in the 
IHA application). The single 150 in\3\ G-airgun will be used if a 
power-down is necessary for mitigation. The G-airgun array will be 
towed behind the St. Laurent at a depth of approximately 11 m (36.1 ft) 
(see Figure B-2 in the IHA application) along predetermined lines in 
water depths ranging from 1,900 to 4,000 m (6,233.6 to 13,123.4 ft). 
One streamer approximately 232 m (761.2 ft) in length with a single 
hydrophone will be towed behind the airgun array at a depth of 
approximately 9 to 30 m (29.5 to 98.4 ft).
    A square wave trigger signal will be supplied to the firing system 
hardware by a FEI-Zyfer GPStarplus Clock model 565, based on GPS time 
(typically at approximately 14 to 20 sec intervals). Vessel speed will 
be approximately 10.2 km/hour (5.5 knots) resulting in a shot interval 
ranging from approximately 39 to 56 m (128 to 183.7 ft). G-airgun 
firing and synchronization will be controlled by a RealTime Systems 
LongShot fire controller, which will send a voltage to the airgun 
solenoid to trigger firing with approximately 54.8 ms delay between 
trigger and fire point.
    Pressurized air for the pneumatic G-airguns will be supplied by two 
Hurricane compressors, model 6T-276-44SB/2500. These are air cooled, 
containerized compressor systems. Each compressor will be powered by a 
C13 Caterpillar engine which turns a rotary screw first stage 
compressor and a three stage piston compressor capable of developing a 
total air volume of 600 SCFM @ 2,500 pounds per square inch (PSI). The 
seismic system will be operated at 1,950 PSI and one compressor could 
easily supply sufficient volume of air under appropriate pressure.
    Seismic acquisition will require a watchkeeper in the seismic lab 
and another in the compressor container. The seismic lab watchkeeper is 
responsible for data acquisition/recording, watching over-the-side 
equipment, airgun firing and log keeping. A remote screen will permit 
monitoring of compressor pressures and alerts, as well as communication 
with the compressor watchkeeper. The compressor watchkeeper will be 
required to monitor the compressor for any emergency shut-down and 
provide general maintenance that might be required during operations.
    Sound level radii for the proposed three airgun array were measured 
in 2009 during a seismic calibration (Mosher et al., 2009; Roth and 
Schmidt, 2010). A transmission loss model was then constructed assuming 
spherical (20LogR) spreading and using the source level estimate 235 dB 
re 1 [micro]Pa (rms) 0-peak; 225 dB re 1 [micro]Pa (rms) from the 
measurements. The use of 20LogR spreading fit the data well out to 
approximately 1 km (0.6 mi) where variability in measured values 
increased (see Appendix B in the IHA application for more details and a 
figure of the transmission loss model compared to the measurement 
data). Additionally, the Gundalf modeling package was used to model the 
airgun array and estimated a source level output of 236.7 dB 0-peak 
(226.7 dB [rms]). Using this slightly stronger source level estimate 
and a 20LogR spreading the 180 and 190 dB (rms) radii are estimated to 
be 216 m (708.7 ft) and 68 m (223.1 ft), respectively. As a 
conservation measure for the proposed safety radii, the sound level 
radii indicated by the empirical data and source models have been 
increased to 500 m (1,640.4 ft) for the 180 dB isopleths and to 100 m 
(328 ft) of the 190 dB isopleths.
    The rms received levels that are used as impact criteria for marine 
mammals are not directly comparable to the peak or peak-to-peak values 
normally used to characterize source levels of airguns. The measurement 
units used above to describe the airgun source, peak or peak-to-peak 
dB, are always higher than the rms dB referred to in much of the 
biological literature. A measured received level of 160 dB (rms) in the 
far field would typically correspond to a peak measurement of about 170 
to 172 dB, at the same location (Greene, 1997;

[[Page 39339]]

McCauley et al., 1998, 2000). The precise 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. However, the 
rms level is always lower than the peak or peak-to-peak level for an 
airgun-type source.

 Table 2--Distances To Which Sound Levels Greater Than or Equal to 190, 180, and 160 dB re 1 [mu]Pa (rms) Could
  Be Received in Deep (Greater Than 1,000 m) Water During the Proposed Survey in the Arctic Ocean, August 7 to
                                                September 3, 2010
----------------------------------------------------------------------------------------------------------------
                                       Tow depth                            Predicted received RMS distances (m)
          Source and volume             (m) Ice/         Water depth      --------------------------------------
                                       open water                             190 dB       180 dB       160 dB
----------------------------------------------------------------------------------------------------------------
Single Mitigation Airgun (150 in\3\)       11/6-7  Deep (>1,000 m).......           30           75          750
3 G-airguns (1,190 in\3\)...........       11/6-7  Deep (>1,000 m).......          100          500        2,500
----------------------------------------------------------------------------------------------------------------

Acoustic Source Specifications--Multibeam Echosounders (MBES), Sub-
Bottom Profiler (SBP) and Acoustic Doppler Current Profilers (ADCP)

    Along with the airgun operations, additional acoustic systems that 
will be operated during the cruise include a 12 kHz Chirp echosounder 
and a 3-5 kHz SBP from the St. Laurent. The Healy will operate a 12 kHz 
Kongsberg MBES, a Knudsen 320BR profiler, a piloting echosounder, and 
two ADCPs. These sources will be operated throughout most of the cruise 
to map bathymetry, as necessary, to meet the geophysical science 
objectives. During seismic operations, these sources will be deployed 
from the St. Laurent and the Healy and will generally operate 
simultaneously with the airgun array deployed from the St. Laurent.
    The Knudsen 320BR echosounder will provide information on depth and 
bottom profile. The Knudsen 320BR is a dual-frequency system with 
operating frequencies of 3.5 and 12 kHz, however, the unit will be 
functioning at the higher frequency, 12 kHz, because the 3.5 kHz 
transducer is not installed.
    While the Knudsen 320BR operates at 12 kHz, its calculated maximum 
source level (downward) is 215 dB re [micro]Pa at 1 m. The pulse 
duration is typically 1.5 to 5 ms with a bandwidth of 3 kHz (FM sweep 
from 3 kHz to 6 kHz). The repetition rate is range dependent, but the 
maximum is a one percent duty cycle. Typical repetition rate is between 
\1/2\ s (in shallow water) to 8 s in deep water. A single 12 kHz 
transducer (sub-bottom) array, consisting of 16 elements in a 4x4 array 
will be used for the Knudsen 320BR. The 12 kHz transducer (TC-12/34) 
emits a conical beam with a width of 30[deg].
    The 3-5 kHz chirp SBP will be towed by and operated from the St. 
Laurent in open water when the St. Laurent is not working in tandem 
with the Healy. The SBP provides information about sedimentary features 
and bottom topography. The chirp system has a maximum 7.2 kW transmit 
capacity into the towed array. The energy from the towed unit is 
directed downward by an array of eight transducers in a conical 
beamwidth of 80 degrees. The interval between pulses will be no less 
than one pulse per second. SBPs of that frequency can produce sound 
levels 200 to 230 dB re 1 [micro]Pa at 1 m (Richardson et al., 1995).
    The Kongsberg EM 122 MBES operates at 10.5 to 13 (usually 12) kHz 
and is hull-mounted on the Healy. The transmitting beamwidth is 1[deg] 
or 2[deg] fore-aft and 150[deg] athwartship. The maximum source level 
is 242 dB re 1 [mu]Pam (rms). Each ``ping'' consists of eight (in water 
greater than 1,000 m deep) or four (less than 1,000 m) successive fan-
shaped transmissions, each ensonifying a sector that extends 1[deg] 
fore-aft. Continuous-wave (CW) pulses increase from two to 15 ms long 
in water depths up to 2,600 m (8,530 ft), and FM chirp pulses up to 100 
ms long are used in water greater than 2,600 m (8,530 ft). The 
successive transmissions span an overall cross-track angular extent of 
about 150[deg], with 2 ms gaps between pulses for successive sectors.
    The Knudsen 320BR hydrographic SBP will provide information on 
sedimentary layering, down to between 20 and 70 m (65.6 to 229.7 ft), 
depending on bottom type and slope. The Knudsen 320 BR is a dual-
frequency system with operating frequencies of 3.5 and 12 kHz; only the 
low frequency will be used during this survey. At 3.5 kHz, the maximum 
output power into the transducer array, as wired on the Healy (where 
the array impedance is approximately 125 ohms), is approximately 6,000 
watts (electrical), which results in a maximum source level of 221 dB 
re 1 [micro]Pa at 1 m downward. Pulse lengths range from 1.5 to 24 ms 
with a bandwidth of 3 kHz (FM sweep from 3 kHz to 6 kHz). The 
repetition rate is range dependent, but the maximum is a one percent 
duty cycle. Typical repetition rate is between \1/2\ s (in shallow 
water) to 8 s in deep water. The 3.5 kHz transducer array on the Healy, 
consisting of 16 (TR109) elements in a 4x4 array, will be used for the 
Knudsen 320BR. At 3.5 kHz the SBP emits a downward conical beam with a 
width of approximately 26[deg].
    The piloting echosounder on the Healy is an Ocean Data Equipment 
Corporation (ODEC) Bathy-1500 that will provide information on water 
depth below the vessel. The ODEC system has a maximum 2 kW transmit 
capacity into the transducer and has two operating modes, single or 
interleaved dual frequency, with available frequencies of 12, 24, 33, 
40, 100, and 200 kHz.
    The 150 kHz ADCP has a minimum ping rate of 0.65 ms. There are four 
beam sectors and each beamwidth is 3[deg]. The pointing angle for each 
beam is 30[deg] off from vertical with one each to port, starboard, 
forward, and aft. The four beams do not overlap. The 150 kHz ADCP's 
maximum depth range is 300 m (984.3 ft).
    The Ocean Surveyor 75 is an ADCP operating at a frequency of 75 
kHz, producing a ping every 1.4 s. The system is a four-beam phased 
array with a beam angle of 30[deg]. Each beam has a width of 4[deg] and 
there is no overlap. Maximum output power is 1 kW with a maximum depth 
range of 700 m (2,296.6 ft).

Acoustic Source Specifications--Icebreaking

    Icebreaking is considered by NMFS to be a continuous sound and NMFS 
estimates that harassment occurs when marine mammals are exposed to 
continuous sounds at a received sound level of 120 dB SPL or above. 
Potential takes of marine mammals may ensue from icebreaking activity 
in which the Healy is expected to engage outside of U.S. waters, i.e., 
north of approximately 74.1[deg] North. While breaking ice, the noise 
from the ship, including impact with ice, engine noise, and propeller 
cavitation, will exceed 120 dB

[[Page 39340]]

continuously. If icebreaking does occur in U.S. waters, USGS expects it 
will occur during seismic operations. The exclusion zone (EZ) for the 
marine mammal Level B harassment threshold during the proposed seismic 
activities is greater than the calculated radius during icebreaking. 
Therefore, if the Healy breaks ice during seismic operations within the 
U.S. waters, the greater radius, i.e, that for seismic operations, 
supersedes that for icebreaking, so no additional takes have been 
estimated within U.S. waters.

Proposed Dates, Duration, and Specific Geographic Area

    The proposed seismic survey will be conducted for approximately 30 
days from approximately August 7 to September 3, 2010. The 
approximately 806 km (501 mi) of tracklines within U.S. waters will be 
surveyed first. These survey lines are expected to be completed by 
approximately August 12, 2010. The seismic vessel St. Laurent will 
depart from Kugluktuk, Nunavut, Canada on August 2, 2010 and return to 
the same port on approximately September 16, 2010. The Healy will 
depart from Dutch Harbor, Alaska on August 3, 2010 to meet the St. 
Laurent by August 7, 2010. After completion of this survey, the Healy 
will change crew through Barrow via helicopter or surface vessel on 
September 4, 2010 (see Table 3 of the IHA application). The entire 
survey area will be bounded approximately by 145[deg] to 158[deg] West 
longitude and 71[deg] to 84[deg] North latitude in water depths ranging 
from approximately 1,900 to 4,000 m (6,234 to 13,123 ft) (see Figure 1 
and Table 1 of the IHA application). Ice conditions are expected to 
range from open water to 10/10 ice cover. See Table 3 of the IHA 
application for a synopsis of the 2010 St. Laurent and Healy Extended 
Continental Shelf expeditions in the Arctic Ocean, August 3 to 
September 16, 2010.
    Icebreaking outside U.S. waters will occur between the latitudes of 
approximately 74[deg] to 84[deg] North. Vessel operations and ice 
conditions from similar survey activities and timing in 2008 and 2009 
were used to estimate the amount of icebreaking (in trackline km) that 
is likely to occur in 2010. USGS expects that the St. Laurent and the 
Healy will be working in tandem through the ice for a maximum of 23 to 
25 days while outside of U.S. waters. The average distance travelled in 
2008 and 2009 when the Healy broke ice for the St. Laurent was 135 km/
day (83.9 mi/day). Based on the 23 to 25 day period of icebreaking, 
USGS calculated that, at most approximately 3,102 to 3,372 km (1,927.5 
to 2,095.3 mi) of vessel trackline may involve icebreaking. This 
calculation is likely an overestimation because icebreakers often 
follow leads when they are available and thus do not break ice at all 
times.

 Table 3--Projected 2010 Icebreaking Effort for USGS/GSC 2010 Extended Continental Shelf Survey in the Northern
                                          Beaufort Sea and Arctic Ocean
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
2008....................................  19........................  2,469.....................             130
2009....................................  27........................  37,744....................             140
Average 2008 to 2009....................  23........................  3,122.....................             135
Projected 2010..........................  23 to 25..................  3,102 to 3,372............              --
----------------------------------------------------------------------------------------------------------------

Description of Marine Mammals in the Proposed Activity Area

    Regarding marine mammals, a total of nine cetacean species, 
including four odontocete (dolphins, porpoises, and small- and large-
toothed whales) species, five mysticete species (baleen whales), and 
five pinniped species (seals, sea lions, and walrus) and the polar bear 
are known to occur in the area affected by the specified activities 
associated with the proposed Arctic Ocean marine seismic survey (see 
Table 3 of USGS's application). Cetaceans and pinnipeds, which are the 
subject of this IHA application, are protected by the MMPA and managed 
by NMFS in accordance with its requirements. In the U.S., the walrus 
and polar bear are managed under the jurisdiction of the U.S. Fish and 
Wildlife Service (USFWS) and are not considered further in this 
analysis. Information on the occurrence, distribution, population size, 
and conservation status for each of the 14 marine mammal species that 
may occur in the proposed project area is presented in Table 4 of 
USGS's application as well as here in the table below (Table 4). 
Several marine mammal species that may be affected by the proposed IHA 
are listed as Endangered or Threatened under Section 4 of the ESA, 
including the bowhead, fin and humpback whale, and polar bear. The 
bowhead whale is common in the Arctic, but unlikely in the survey area. 
Based on a small number of sightings in the Chukchi Sea, the fin whale 
is unlikely to be encountered along the planned trackline in the Arctic 
Ocean. Humpback whales are uncommon in the Chukchi Sea and normally do 
not occur in the Beaufort Sea. Several humpback sightings were recorded 
during vessel-based surveys in the Chukchi Sea in 2007 (three 
sightings) and 2008 (one sighting; Haley et al., 2009). The only known 
occurrence of humpback whale in the Beaufort Sea was a single sighting 
of a cow and calf reported and photographed in 2007 (Green et al., 
2007). Based on the low number of sightings in the Chukchi and Beaufort 
seas, humpback whales would be unlikely to occur in the vicinity of the 
proposed geophysical activities.
    The marine mammal species under NMFS jurisdiction most likely to 
occur in the seismic survey area include two cetacean species (beluga 
and bowhead whales), and two pinniped species (ringed and bearded 
seals). These species however, will likely occur in low numbers and 
most sightings will likely occur in locations within 100 km (62 mi) of 
shore where no seismic work is planned. The marine mammal most likely 
to be encountered throughout the cruise is the ringed seal.
    Seven additional cetacean species--narwhal, killer whale, harbor 
porpoise, gray whale, minke whale, fin whale, and humpback whale--could 
occur in the project area. Gray whales occur regularly in continental 
shelf waters along the Chukchi Sea coast in summer and to a lesser 
extent along the Beaufort Sea coast. Recent evidence from monitoring 
activities in the Chukchi and Beaufort seas during industry seismic 
surveys suggests that harbor porpoise and minke whales, which have been 
considered uncommon or rare in the Chukchi and Beaufort seas, may be 
increasing in numbers in these areas (Funk et al., 2009). Small numbers 
of killer whales have also been recorded during these industry surveys, 
along with a few sightings of fin and humpback whales. The narwhal 
occurs in Canadian waters and occasionally in the Beaufort Sea, but is 
rare there and not expected to be encountered. Each of these species is 
uncommon or rare in the Chukchi and Beaufort seas, and relatively few 
if any encounters with

[[Page 39341]]

these species are expected during the seismic program.
    Additional pinniped species that could be encountered during the 
proposed seismic survey include spotted and ribbon seals, and Pacific 
walrus. Spotted seals are more abundant in the Chukchi Sea and occur in 
small numbers in the Beaufort Sea. The ribbon seal is uncommon in the 
Chukchi Sea and there are few sightings in the Beaufort Sea. The 
Pacific walrus is common in the Chukchi Sea, but uncommon in the 
Beaufort Sea and not likely to occur in the deep waters of the proposed 
survey area. None of these species would likely be encountered during 
the proposed cruise other than perhaps transit periods to and from the 
survey area.
    Table 4 below outlines the marine mammal species, their habitat and 
abundance in the proposed project area, their conservation status, and 
density. Additional information regarding the distribution of these 
species expected to be found in the proposed project area and how the 
estimated densities were calculated may be found in USGS's application.

 Table 4--The Habitat, Regional Abundance, Conservation Status, and Best and Maximum Density Estimates of Marine
 Mammals That Could Occur in or Near the Proposed Seismic Survey Area in the Arctic Ocean. See Table 4 in USGS's
                                         Application for Further Detail
----------------------------------------------------------------------------------------------------------------
                                                                                     Best \b\         Max \c\
                                                                                      Density         Density
                                                    Abundance/                      (/     (/
           Species                  Habitat          regional          ESA\a\       km\2\) open     km\2\) open
                                                    population                      water, ice      water, ice
                                                      size\a\                      margin, polar   margin, polar
                                                                                       pack            pack
----------------------------------------------------------------------------------------------------------------
Odontocetes:
    Beluga whale               Offshore,         3,710\d\,         NL                     0.0354          0.0709
     (Delphinapterus leucas).   coastal, ice      39,257\e\.                              0.0354          0.0709
                                edges.                                                    0.0035          0.0071
    Narwhal (Monodon           Offshore, ice     Rare\f\.........  NL                     0.0000          0.0001
     monocerus).                edge.                                                     0.0000          0.0002
                                                                                          0.0000          0.0001
Killer whale (Orcinus orca)..  Widely            Rare............  NL                     0.0000          0.0001
                                distributed.                                              0.0000          0.0001
                                                                                          0.0000          0.0001
Harbor porpoise (Phocoena      Coastal, inland   Common            NL                     0.0000          0.0001
 phocoena).                     waters, shallow   (Chukchi),                              0.0000          0.0001
                                offshore waters.  Uncommon                                0.0001          0.0001
                                                  (Beaufort).
Mysticetes:
    Bowhead whale (Balaena     Pack ice and      10,545\g\.......  EN                     0.0061          0.0122
     mysticetus).               coastal.                                                  0.0061          0.0122
                                                                                          0.0006          0.0012
    Eastern Pacific gray       Coastal, lagoons  488\h\,           NL                     0.0000          0.0001
     whale (Eschrichtius                          17,500\i\.                              0.0000          0.0001
     robustus).                                                                           0.0000          0.0001
    Minke whale (Balaenoptera  Shelf, coastal..  Small numbers...  NL                     0.0000          0.0001
     acutorostrata).                                                                      0.0000          0.0001
                                                                                          0.0000          0.0001
    Fin whale (Balaenoptera    Slope, mostly     Rare (Chukchi)..  E                      0.0000          0.0001
     physalus).                 pelagic.                                                  0.0000          0.0001
                                                                                          0.0000          0.0001
    Humpback whale (Megaptera  Shelf, coastal..  Rare............  EN                     0.0000          0.0001
     novaeangliae).                                                                       0.0000          0.0001
                                                                                          0.0000          0.0001
Pinnipeds:
    Bearded seal (Erignathus   Pack ice, open    300,000-450,000\  C                      0.0096          0.0384
     barbatus).                 water.            j\.                                     0.0128          0.0512
                                                                                          0.0013          0.0051
    Spotted seal (Phoca        Pack ice, open    59,214\k\.......  P-T                    0.0001          0.0004
     largha).                   water, coastal                                            0.0001          0.0004
                                haul-outs.                                                0.0000          0.0000
    Ringed seal (Pusa          Landfast and      18,000\l\,        C                      0.1883          0.7530
     hispida).                  pack ice, open    208,000-252,000                         0.2510          1.0040
                                water.            \m\.                                    0.0251          0.1004
    Ribbon seal (Histriophoca  Pack ice, open    90,000-100,000\n  NL                       N.A.            N.A.
     fasciata).                 water.            \.
Pacific walrus (Odobenus       Ice, coastal....  N.A.............  NL                       N.A.            N.A.
 rosmarus divergens).
Carnivores:
    Polar bear (Ursus          Ice, coastal....  N.A.............  T                        N.A.            N.A.
     maritimus marinus).
----------------------------------------------------------------------------------------------------------------
N.A.--Data not available or species status was not assessed,
\a\ U.S. Endangered Species Act: EN = Endangered, T = Threatened, C = Candidate, P = Proposed, NL = Not listed.
\b\ Best estimate as listed in Table 5 and Add-3 of the application.
\c\ Maximum estimate as listed in Table 5 and Add-3 of the application.
\d\ Eastern Chukchi Sea stock based on 1989 to 1991 surveys with a correction factor (Angliss and Allen, 2009).
\e\ Beaufort Sea stock based on surveys in 1992 (Angliss and Allen, 2009).
\f\ DFO (2004) states the population in Baffin Bay and the Canadian Arctic archipelago is approximately 60,000;
  very few of these enter the Beaufort Sea.

[[Page 39342]]

 
\g\ Abundance of bowhead whales surveyed near Barrow, as of 2001 (George et al., 2004). Revised to 10,545 by Zeh
  and Punt (2005).
\h\ Southern Chukchi Sea and northern Bering Sea (Clarks and Moore, 2002).
\i\ Eastern North Pacific gray whale population (Rugh et al., 2008).
\j\ Based on earlier estimates, no current population estimate available (Angliss and Allen, 2009).
\k\ Alaska stock based on aerial surveys in 1992 (Angliss and Allen, 2009).
\l\ Beaufort Sea minimum estimate with no correction factor based on aerial surveys in 1996 to 1999 (Frost et
  al., 2002 in Angliss and Allen, 2009).
\m\ Eastern Chukchi Sea population (Bengston et al., 2005).
\n\ Bering Sea population (Burns, 1981a in Angliss and Allen, 2009).

    Within the latitudes of the proposed survey when the Healy will be 
breaking ice outside of U.S. waters, no cetaceans were observed by PSOs 
along approximately 21,322 km (13,248.9 mi) of effort during projects 
in 2005, 2006, 2008, and 2009 (Haley and Ireland, 2006; Haley, 2006; 
Jackson and DesRoches, 2008; Mosher et al., 2009). The estimated 
maximum amount of icebreaking outside of U.S. waters for this project, 
i.e., 3,372 line km (2,095.3 mi), is considerably less than the 
combined trackline for the aforementioned projects. At least one PSO 
will stand watch at all times while the Healy is breaking ice for the 
St. Laurent. USGS does not expect that PSOs will observe any cetaceans 
during the proposed survey. Seals were reported by PSOs during the 
2005, 2006, 2008, and 2009 effort within the latitudes of the proposed 
survey.

 Table 5--Number of Pinnipeds Reported During 2005, 2006, 2008, and 2009
   Projects Within the Latitudes Where the Healy Will Be Breaking Ice
 Outside of U.S. Waters for the Proposed Arctic Ocean Survey (Haley and
 Ireland, 2006; Haley, 2006, GSC Unpublished Data, 2008; Mosher et al.,
                                  2009)
------------------------------------------------------------------------
                                             Number of       Number of
            Pinniped species                 sightings      individuals
------------------------------------------------------------------------
Ringed seal.............................             116             125
Bearded seal............................              24              26
Unidentified seal.......................             128             140
                                         -------------------------------
    Totals..............................             268             291
------------------------------------------------------------------------

Potential Effects on Marine Mammals

Potential Effects of Airgun Sounds

    The effects of sounds from airguns might result in one or more of 
the following: Tolerance, masking of natural sounds, behavioral 
disturbances, 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 project would result in any 
cases of temporary or especially permanent hearing impairment, or any 
significant non-auditory physical or physiological effects. Some 
behavioral disturbance is expected, but this would be localized and 
short-term. NMFS concurs with this determination.
    The root mean square (rms) received levels that are used as impact 
criteria for marine mammals are not directly comparable to the peak or 
peak-to-peak values normally used to characterize source levels of 
airgun arrays. The measurement units used to describe airgun sources, 
peak or peak-to-peak decibels, are always higher than the rms decibels 
referred to in biological literature. A measured received level of 160 
dB (rms) in the far field would typically correspond to a peak 
measurement of approximately 170 to 172 dB, and to a peak-to-peak 
measurement of approximately 176 to 178 dB, as measured for the same 
pulse received at the same location (Greene, 1997; McCauley et al., 
1998, 2000a). The precise difference between rms and peak or peak-to-
peak values depends on the frequency content and duration of the pulse, 
among other factors. However, the rms level is always lower than the 
peak or peak-to-peak level for an airgun-type source.

Tolerance

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

Masking

    Obscuring of sounds of interest by interfering sounds, generally at 
similar frequencies, is known as masking. Masking effects of pulsed 
sounds (even from large arrays of airguns) on marine mammal calls and 
other natural sounds are expected to be limited, although there are few 
specific data of relevance. Because of the intermittent nature and low 
duty cycle of seismic pulses, animals can emit and receive sounds in 
the relatively quiet intervals between pulses. However in exceptional 
situations, reverberation occurs for much or all of the interval 
between pulses (Simard et al., 2005; Clark and Gagnon, 2006) which 
could mask calls. Some baleen and toothed whales are known to continue 
calling in the presence of seismic pulses. The airgun sounds are 
pulsed, with quiet periods between the pulses, and whale calls often 
can be heard between the seismic pulses (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; Dunn et al., 2009). 
In the northeast Pacific Ocean, blue whale calls have been recorded 
during a seismic survey off Oregon (McDonald et al., 1995). Clark and 
Gagnon (2006) reported that fin whales in the northeast Pacific Ocean 
went silent for an extended period starting soon after the onset of a 
seismic survey in the area. Similarly, there has been one report that 
sperm whales ceased calling when exposed to pulses from a very distant 
seismic ship (Bowles et al., 1994). However, more recent studies found 
that they continued calling the presence of seismic pulses (Madsen et 
al., 2002; Tyack et al., 2003; Smultea et al., 2004; Holst et al., 
2006; Jochens et al., 2008). Bowhead whale calls are frequently 
detected in the presence of seismic pulses, although the

[[Page 39343]]

number of calls detected may sometimes be reduced in the presence of 
airgun pulses (Richardson et al., 1986; Greene et al., 1999; Blackwell 
et al., 2008). Dolphins and porpoises commonly are heard calling while 
airguns are operating (Gordon et al., 2004; Smultea et al., 2004; Holst 
et al., 2005a,b; Potter et al., 2007). The sounds important to small 
odontocetes are predominantly at much higher frequencies than the 
dominant components of airgun sounds, thus limiting the potential for 
masking. In general, masking effects of seismic pulses are expected to 
be minor (in the case of smaller odontocetes), given the normally 
intermittent nature of seismic pulses. Masking effects on marine 
mammals are discussed further in Appendix D (4) of the IHA application.

Disturbance Reactions

    Disturbance includes a variety of effects, including subtle changes 
in behavior, more conspicuous changes in activities, and displacement. 
Reactions to sound, if any, depend on species, state of maturity, 
experience, current activity, reproductive state, time of day, and many 
other factors (Richardson et al., 1995; Wartzok et al., 2004; Southall 
et al., 2007; Weilgart, 2007). If a marine mammal does react to an 
underwater sound by changing its behavior or moving a small distance, 
the response may or may not rise to the level of ``harassment'' to the 
individual, or affect the stock or the species population as a whole. 
However, if a sound source displaces marine mammals from an important 
feeding or breeding area for a prolonged period, impacts on individuals 
and populations could be significant (e.g., Lusseau and Bejder, 2007; 
Weilgart, 2007). Given the many uncertainties in predicting the 
quantity and types of impacts of noise on marine mammals, it is common 
practice to estimate how many mammals are likely to be present within a 
particular distance of industrial activities, and/or exposed to a 
particular level of industrial sound. In most cases, this practice 
potentially overestimates the numbers of marine mammals that would be 
affected in some biologically-important manner.
    The sound exposure criteria used to estimate how many marine 
mammals might be disturbed to some biologically-important degree by a 
seismic program are based primarily on behavioral observations during 
studies of several species. However, information is lacking for many 
species. Detailed studies have been done on humpback, gray, bowhead, 
and on ringed seals. Less detailed data are available for some other 
species of baleen whales, sperm whales, small toothed whales, and sea 
otters, but for many species there are no data on responses to marine 
seismic surveys.
    Baleen Whales--Baleen whales generally tend to avoid operating 
airguns, but avoidance radii are quite variable. Whales are often 
reported to show no overt reactions to pulses from large arrays of 
airguns at distances beyond a few kilometers, even though the airgun 
pulses remain well above ambient noise levels out to much longer 
distances. However, as reviewed in Appendix D (5) of the USGS IHA 
application, baleen whales exposed to strong noise pulses from airguns 
often react by deviating from their normal migration route and/or 
interrupting their feeding activities and moving away from the sound 
source. In the case of the migrating gray and bowhead whales, the 
observed changes in behavior appeared to be of little or no biological 
consequence to the animals. They simply avoided the sound source by 
displacing their migration route to varying degrees, but within the 
natural boundaries of the migration corridors.
    Studies of gray, bowhead, and humpback whales have demonstrated 
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 (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 (2.8 to 9 mi) from the 
source. A substantial proportion of the baleen whales within those 
distances may show avoidance or other strong behavioral reactions to 
the airgun array. Subtle behavioral changes sometimes become evident at 
somewhat lower received levels, and studies summarized in Appendix D 
(5) of the USGS IHA application have shown that some species of baleen 
whales, notably bowhead and humpback whales, at times show strong 
avoidance at received levels lower than 160 to 170 dB re 1 [mu]Pa 
(rms).
    Bowhead whales migrating west across the Alaskan Beaufort Sea in 
autumn, in particular, are unusually responsive, with substantial 
avoidance occurring out to distances of 20 to 30 km (12.4 to 18.6 mi) 
from a medium-sized airgun source at received sound levels of around 
120 to 130 dB re 1 [mu]Pa (rms) (Miller et al., 1999; Richardson et 
al., 1999; see Appendix D (5) of the IHA application). However, more 
recent research on bowhead whales (Miller et al., 2005a; Harris et al., 
2007; Lyons et al., 2009; Christi et al., 2009) corroborates earlier 
evidence that, during the summer feeding season, bowheads are not as 
sensitive to seismic sources. Nonetheless, subtle but statistically 
significant changes in surfacing-respiration-dive cycles were evident 
upon statistical analysis (Richardson et al., 1986). In summer, 
bowheads typically begin to show avoidance reactions at a received 
level of about 152 to 178 dB re 1 [mu]Pa (rms) (Richardson et al., 
1986, 1995; Ljungblad et al., 1988; Miller et al., 2005a). The USGS 
project will be conducted during fall migration at locations greater 
than 200 nmi offshore, well north of the known bowhead migration 
corridor. Recent evidence suggests that some bowheads feed during 
migration and feeding bowheads might be encountered in the central 
Alaska Beaufort Sea during transit periods to and from Barrow (Lyons et 
al., 2009; Christi et al., 2009). The primary bowhead summer feeding 
grounds however, are far to the east in the Canadian Beaufort Sea.
    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. Malme et al. (1986, 1988) estimated, based on small sample sizes, 
that 50 percent of feeding gray whales ceased 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 with 
observations of Western Pacific gray whales feeding off Sakhalin 
Island, Russia, when a seismic survey was underway just offshore of 
their feeding area (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, Bryde's, and minke 
whales) have occasionally been reported in areas ensonified by airgun 
pulses (Stone, 2003; MacLean and Haley, 2004; Stone and Tasker, 2006), 
and calls from blue and fin whales have been localized in areas with 
airgun operations (e.g. McDonald et al., 1995; Dunn et al., 2009). 
Sightings by observers on seismic vessels off the United Kingdom from 
1997 to 2000 suggest that, during times of good sightability, sighting 
rates for

[[Page 39344]]

mysticetes (mainly fin and sei whales) were similar when large arrays 
of airguns were shooting and not shooting (silent) (Stone, 2003; Stone 
and Tasker, 2006). However, these whales tended to exhibit localized 
avoidance, remaining significantly further (on average) from the airgun 
array during seismic operations compared with non-seismic periods 
(Stone and Tasker, 2006). In a study off of Nova Scotia, Moulton and 
Miller (2005) found little difference in sighting rates (after 
accounting for water depth) and initial sighting distances of 
balaenopterid whales when airguns were operating vs. silent. However, 
there were indications that these whales were more likely to be moving 
away when seen during airgun operations. Similarly, ship-based 
monitoring studies of blue, fin, sei, and minke whales offshore of 
Newfoundland (Orphan Basin and Laurentian Sub-basin) found no more than 
small differences in sighting rates and swim direction during seismic 
vs. non-seismic periods (Moulton et al., 2005, 2006a,b).
    Data on short-term reactions (or lack of reactions) of 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 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 
(see Appendix A in Malme et al., 1984; Richardson et al., 1995; Angliss 
and Outlaw, 2008). The Western Pacific gray whale population did not 
seem affected by a seismic survey in its feeding ground during a prior 
year (Johnson et al., 2007). Similarly, bowhead whales have continued 
to travel to the eastern Beaufort Sea each summer, and their numbers 
have increased notably, despite seismic exploration in their summer and 
autumn range for many years (Richardson et al., 1987; Angliss and 
Outlaw, 2008). Populations of both gray whales and bowhead whales grew 
substantially during this time. In any event, the brief exposures to 
sound pulses from the proposed airgun source are highly 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 and (in 
more detail) in Appendix D of the IHA application have been reported 
for toothed whales. However, recent systematic studies on sperm whales 
have been done (Gordon et al., 2006; Madsen et al., 2006; Winsor and 
Mate, 2006; Jochens et al., 2008; Miller et al., 2009). There is an 
increasin