[Federal Register Volume 75, Number 130 (Thursday, July 8, 2010)]
[Notices]
[Pages 39336-39364]
From the Federal Register Online via the Government Publishing 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  

[[Page 39336]]


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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 [email protected]. 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 http://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: http://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

[[Page 39337]]

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
----------------------------------------------------------------------------------------------------------------
                                                                                                    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

[[Page 39338]]

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: http://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 
increasing amount of information about responses of various odontocetes 
to seismic surveys based on monitoring studies (e.g., Stone, 2003; 
Smultea et al., 2004; Moulton and Miller, 2005; Bain and Williams, 
2006; Holst et al., 2006; Stone and Tasker, 2006; Potter et al., 2007; 
Hauser et al., 2008; Holst and Smultea, 2008; Weir, 2008; Barkaszi et 
al., 2009; Richardson et al., 2009).
    Seismic operators and observers on seismic vessels regularly see 
dolphins and other small toothed whales near operating airgun arrays, 
but in general there seems to be a tendency for most delphinids to show 
some limited avoidance of operating seismic vessels with large airgun 
arrays (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). However, 
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 airgun 
arrays are firing (Moulton and Miller, 2005). Nonetheless, there have 
been indications that 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 (Goold, 
1996a,b,c; Calambokidis and Osmek, 1998; Stone, 2003; Stone and Tasker, 
2006; Weir, 2008). In most cases, the avoidance radii for delphinids 
appear to be small, on the order of 1 km (0.62 mi) or less, and some 
individuals show no apparent avoidance. The beluga is a species that 
(at least at times) shows long-distance avoidance of seismic vessels. 
Aerial surveys during seismic operations in the southeastern Beaufort 
Sea during summer found that sighting rates of beluga whales were 
significantly lower at distances 10 to 20 km (6.2 to 12.4 mi) compared 
with 20 to 30 km (12.4 to 18.6 mi) from an operating airgun array, and 
observers on seismic boats in that area rarely see belugas (Miller et 
al., 2005; Harris et al., 2007).
    Captive bottlenose dolphins 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; Finneran and Schlundt, 2004). However, the animals tolerated high 
received levels of sound (pk-pk level greater than 200 dB re 1 
[micro]Pa) before exhibiting aversive behaviors. With the presently-
planned source, such levels would be limited to distances less than 200 
m (656.2 ft) of the three airgun array. The reactions of belugas to the 
USGS survey are likely to be more similar to those of free-ranging 
belugas exposed to airgun sound (Miller et al., 2005) than to those of 
captive belugas exposed to a different type of strong transient sound 
(Finneran et al., 2000, 2002).
    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; 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 operations 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 in general (Richardson 
et al., 1995; Southall et al., 2007).
    Odontocete reactions to large arrays of airguns are variable and, 
at least for delphinids and Dall's porpoises, seem to be confined to a 
smaller radius than has been observed for the more responsive of the 
mysticetes, belugas, and harbor porpoises (Appendix C of the IHA 
application).
    Pinnipeds--Pinnipeds are not likely to show a strong avoidance 
reaction to the airgun sources that will be used. Visual monitoring 
from seismic vessels has shown only slight (if any) avoidance of 
airguns by pinnipeds, and only slight (if any) changes in behavior--see 
Appendix D (5) of the IHA application. Ringed seals frequently do not 
avoid the area within a few hundred meters of operating airgun arrays 
(Harris et al., 2001; Moulton and Lawson, 2002; Miller et al., 2005). 
However, initial telemetry work suggests that avoidance and other 
behavioral reactions by two other species of seals to small airgun 
sources may at times be stronger than evident to date from visual 
studies of pinnipeds reactions to airguns (Thompson et al., 1998). Even 
if reactions of the species occurring in the present study area are as 
strong as those evident in the telemetry study, reactions are expected 
to be confined to relatively small distances and durations, with no 
long-term effects on pinniped individuals or populations.

[[Page 39345]]

Hearing Impairment and Other Physical Effects

    Temporary or permanent hearing impairment is a possibility when 
marine mammals are exposed to very strong sounds, but there has been no 
specific documentation of this for marine mammals exposed to sequences 
of airgun pulses.
    NMFS is presently developing new noise exposure criteria for marine 
mammals that take account of the now-available scientific data on 
temporary threshold shift (TTS), the expected offset between the TTS 
and permanent threshold shift (PTS) thresholds, differences in the 
acoustic frequencies to which different marine mammal groups are 
sensitive, and other relevant factors. Detailed recommendations for new 
science-based noise exposure criteria were published in late 2007 
(Southall et al., 2007).
    Several aspects of the planned monitoring and mitigation measures 
for this project (see below) are designed to detect marine mammals 
occurring near the airguns to avoid exposing them to sound pulses that 
might, at least in theory, cause hearing impairment. In addition, many 
cetaceans are likely to show some avoidance of the area where received 
levels of airgun sound are high enough such that hearing impairment 
could potentially occur. In those cases, the avoidance responses of the 
animals themselves will reduce or (most likely) avoid any possibility 
of hearing impairment.
    Non-auditory physical effects may also occur in marine mammals 
exposed to strong underwater pulsed sound. Possible types of non-
auditory physiological effects or injuries that might (in theory) occur 
in mammals close to a strong sound source include stress, neurological 
effects, bubble formation, and other types of organ or tissue damage. 
It is possible that some marine mammal species (i.e., beaked whales) 
may be especially susceptible to injury and/or stranding when exposed 
to strong pulsed sounds. However, as discussed below, there is no 
definitive evidence that any of these effects occur even for marine 
mammals in close proximity to large arrays of airguns and beaked whales 
do not occur in the proposed study area. It is especially unlikely that 
any effects of these types would occur during the present project given 
the brief duration of exposure of any given mammal, the deep water in 
the study area, and the proposed monitoring and mitigation measures 
(see below). The following subsections discuss in somewhat more detail 
the possibilities of TTS, PTS, and non-auditory physical effects.
    Temporary Threshold Shift--TTS is the mildest form of hearing 
impairment that can occur during exposure to a strong sound (Kryter, 
1985). While experiencing TTS, the hearing threshold rises and a sound 
must be stronger in order to be heard. At least in terrestrial mammals, 
TTS can last from minutes or hours to (in cases of strong TTS) days. 
For sound exposures at or somewhat above the TTS threshold, hearing 
sensitivity in both terrestrial and marine mammals recovers rapidly 
after exposure to the noise ends. Few data on sound levels and 
durations necessary to elicit mild TTS have been obtained for marine 
mammals, and none of the published data concern TTS elicited by 
exposure to multiple pulses of sound. Available data on TTS in marine 
mammals are summarized in Southall et al. (2007).
    For toothed whales exposed to single short pulses, the TTS 
threshold appears to be, to a first approximation, a function of the 
energy content of the pulse (Finneran et al., 2002, 2005). Given the 
available data, the received level of a single seismic pulse might need 
to be approximately 210 dB re 1 [mu]Pa (rms) (approximately 221 to 226 
dB pk-pk) in order to produce brief, mild TTS. Exposure to several 
seismic pulses at received levels near 200 to 205 dB (rms) might result 
in slight TTS in a small odontocete, assuming the TTS threshold is (to 
a first approximation) a function of the total received pulse energy. 
Seismic pulses with received levels of 200 to 205 dB or more are 
usually restricted to a radius of no more than 200 m (656.2 ft) around 
a seismic vessel operating a large array of airguns.
    For baleen whales, there are no data, direct or indirect, on levels 
or properties of sound required to induce TTS. The frequencies to which 
baleen whales are most sensitive are lower than those to which 
odontocetes are more sensitive, and natural background noise levels at 
those low frequencies tend to be higher. As a result, auditory 
thresholds of baleen whales within their frequency band of best hearing 
are believed to be higher (less sensitive) than are those of 
odontocetes at their best frequencies (Clark and Ellison, 2004). From 
this, it is suspected that received levels causing TTS onset may also 
be higher in baleen whales (Southall et al., 2007). However, no cases 
of TTS are expected given the moderate size of the source and the 
strong likelihood that baleen whales (especially migrating bowheads) 
would avoid the approaching airguns (or vessel) before being exposed to 
levels high enough for there to be any possibility of TTS.
    In pinnipeds, TTS thresholds associated with exposure to brief 
pulses (single or multiple) of underwater sound have not been measured. 
Initial evidence from prolonged exposures suggested that some pinnipeds 
may incur TTS at somewhat lower received levels than do small 
odontocetes exposed for similar durations (Kastak et al., 1999, 2005; 
Ketten et al., 2001; Au et al., 2000). For harbor seal, which is 
closely related to the ringed seal, TTS onset apparently occurs at 
somewhat lower received energy levels than for odontocetes (see 
Appendix D of the IHA application).
    A marine mammal within a radius of less than or equal to 100 m (328 
ft) around a typical large array of operating airguns might be exposed 
to a few seismic pulses with levels of greater than 205 dB (rms), and 
possibly more pulses if the mammal moved with the seismic vessel. The 
received sound levels will be reduced for the proposed three airgun 
array to be used during the current survey compared to the larger 
arrays thus reducing the potential for TTS for the proposed survey. (As 
noted above, most cetacean species trend to avoid operating airguns, 
although not all individuals do so.) However, several of the 
considerations that are relevant in assessing the impact of typical 
seismic surveys with arrays of airguns are not directly applicable 
here:
     ``Ramping-up'' (soft-start) is standard operational 
protocol during start-up of large airgun arrays. Ramping-up involves 
starting the airguns in sequence, usually commencing with a single 
airgun and gradually adding additional airguns.
     It is unlikely that cetaceans would be exposed to airgun 
pulses at a sufficiently high level for a sufficiently long period to 
cause more than mild TTS, given the relative movement of the vessel and 
the marine mammal. For the proposed project, the seismic survey will be 
in deep water where the radius of influence and duration of exposure to 
strong pulses is smaller compared to shallow locations.
     With a large array of airguns, TTS would be most likely in 
any odontocetes that bow-ride or in any odontocetes or pinnipeds that 
linger near the airguns. For the proposed survey, the anticipated 180 
dB and 190 dB (re 1 [mu]Pa 1m rms) exclusion zone in deep water are 
expected to extend 483 m (1,584.7 ft) and 153m (502 ft), respectively, 
from the airgun array which could result in effects to bow-riding 
species. However, no species that occur within the project area are 
expected to bow-ride.

[[Page 39346]]

     There is a possibility that a small number of seals (which 
often show little or no avoidance of approaching seismic vessels) could 
occur close to the airguns and that they might incur slight TTS if no 
mitigation action (shut-down) were taken.
    To avoid the potential for injury, 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. All airgun activity will occur in water depths ranging 
from approximately 2,000 to 4,000 m (6,561.7 to 13,123.4 ft). Sound 
level radii of the proposed three airgun array were measured in 2009 
during a seismic calibration experiment (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 [mu]Pa 0-peak; 225 dB re 1 [mu]Pa rms) from the measurements. 
The use of 20LogR spreading fit the data well out to approximately one 
km (0.6 mi) where variability in measures values increased (see 
Appendix B of 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 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 conservative measure for 
the proposed EZ, 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 (rms) isopleths and to 100 m (328 ft) for the 190 dB isopleth (see 
Table 2 of the IHA application). These distances will be used as power-
down/shut-down criteria described in the Proposed Mitigation and 
Proposed Monitoring and Reporting sections below. Furthermore, 
established 180 and 190 dB (rms) criteria are not considered to be the 
level 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 cetaceans. As summarized 
above and in Southall et al. (2007), data that are now available imply 
that TTS is unlikely to occur in most odontocetes (and probably 
mysticetes as well) unless they are exposed to a sequence of several 
airgun pulses stronger than 180 or 190 dB re 1 [mu]Pa (rms). Since no 
bow-riding species occur in the study area, it is unlikely such 
exposures will occur.
    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 (Richardson et al., 1995; Gedamke et al., 
2008). Single or occasional occurrences of mild TTS are not indicative 
of permanent auditory damage, but repeated or (in some cases) single 
exposures to a level well above that causing TTS onset might elicit 
PTS.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, but are assumed to be similar to those in humans and 
other terrestrial mammals. PTS might occur at a received sound level at 
least several decibels above that inducing mild TTS if the animal were 
exposed to strong sound pulses with rapid rise time (see Appendix D (6) 
of the IHA application). 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). On an SEL basis, Southall et 
al. (2007) estimated that received levels would need to exceed the TTS 
threshold by at least 15 dB for there to be risk of PTS. Thus, for 
cetaceans they estimate that the PTS threshold might be an M-weighted 
SEL (for the sequence of received pulses) of approximately 198 dB re 1 
[mu]Pa\2\[middot]s (15 dB higher than the Mmf-weighted TTS 
threshold, in a beluga, for a watergun impulse), where the SEL value is 
cumulated over the sequence of pulses.
    Southall et al. (2007) also note that, regardless of the SEL, there 
is concern about the possibility of PTS if a cetacean or pinniped 
receives one or more pulses with peak pressure exceeding 230 or 218 dB 
re 1 [mu]Pa (peak), respectively. Thus PTS might be expected upon 
exposure of cetaceans to either SEL greater than or equal to 198 dB re 
1 [mu]Pa\2\[middot]s or peak pressure greater than or equal to 230 dB 
re 1 [mu]Pa. Corresponding proposed dual criteria for pinnipeds (at 
least harbor seals) are greater than or equal to 186 dB SEL and greater 
than or equal to 218 dB peak pressure (Southall et al., 2007). These 
estimates are all first approximations, given the limited underlying 
data, assumptions, species differences, and evidence that the ``equal 
energy'' model may not be entirely correct. A peak pressure of 230 dB 
re 1 [mu]Pa (3.2 bar [middot]m, 0-pk), which would only be found within 
a few meters of the largest (360 in \3\) airguns in the planned airgun 
array (Caldwell and Dragoset, 2000). A peak pressure of 218 dB re 1 
[mu]Pa could be received somewhat farther away; to estimate that 
specific distance, one would need to apply a model that accurately 
calculates peak pressures in the near-field around an array of airguns.
    Given the higher level of sound necessary to cause PTS as compared 
with TTS, it is considerably less likely that PTS could occur. Baleen 
whales generally avoid the immediate area around operating seismic 
vessels, as do some other marine mammals. The planned monitoring and 
mitigation measures, including visual monitoring, power-downs, and 
shut-downs of the airguns when mammals are seen within or approaching 
the EZs will further reduce the probability of exposure of marine 
mammals to sounds strong enough to induce PTS.
    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. If any such effects do occur, they 
probably would be limited to unusual situations when animals might be 
exposed at close range for unusually long periods. It is doubtful that 
any single marine mammal would be exposed to strong seismic sounds for 
sufficiently long that significant physiological stress would develop. 
That is especially so in the case of the proposed project where the 
airgun configuration focuses most energy downward, the ship will 
typically be moving at four to five knots, and for the most part, the 
tracklines will not ``double back'' through the same area. However, 
resonance effects (Gentry, 2002) and direct noise-induced bubble 
formation (Crum et al., 2005) are implausible in the case of exposure 
to an impulsive broadband source like an airgun array. If seismic 
surveys disrupt

[[Page 39347]]

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. Beaked whales do not occur in 
the proposed survey area.
    In general, little is known about the potential for seismic survey 
sounds (or other types of strong underwater sounds) to cause non-
auditory physical effects in marine mammals. Such effects, if they 
occur at all, would presumably be limited to short distances and to 
activities that extend over a prolonged period. The available data do 
not allow identification of a specific exposure level above which non-
auditory effects can be expected (Southall et al., 2007), or any 
meaningful quantitative predictions of the numbers (if any) of marine 
mammals that might be affected in those ways. Marine mammals that show 
behavioral avoidance of seismic vessels, including most baleen whales 
and some odontocetes (including belugas), and some pinnipeds, are 
especially unlikely to incur non-auditory physical effects. Also, the 
planned monitoring and mitigation measures, including shut-down of the 
airguns, will reduce any such effects that might otherwise occur.
    Strandings and Mortality--Marine mammals close to underwater 
detonations of high explosives can be killed or severely injured, and 
their auditory organs are especially susceptible to injury (Ketten et 
al., 1993; Ketten, 1995). However, explosives are no longer used for 
marine waters for commercial seismic surveys or (with rare exceptions) 
for seismic research; they have been replaced entirely by airguns or 
related non-explosive pulse generators. Airgun pulses are less 
energetic and have slower rise times, and there is no proof that they 
can cause serious injury, death, or stranding even in the case of large 
airgun arrays. However, the association of mass strandings of beaked 
whales with naval exercises and, in one case, an L-DEO seismic survey 
(Malakoff, 2002; Cox et al., 2006), has raised the possibility that 
beaked whales exposed to strong pulsed sounds may be especially 
susceptible to injury and/or behavioral reactions that can lead to 
stranding (Hildebrand, 2005; Southall et al., 2007). Appendix D(6) of 
the USGS IHA application provides additional details.
    Specific sound-related processes that lead to strandings and 
mortality are not well documented, but may include:
    (1) Swimming in avoidance of a sound into shallow water;
    (2) A change in behavior (such as a change in diving behavior) that 
might contribute to tissue damage, gas bubble formation, hypoxia, 
cardiac arrhythmia, hypertensive hemorrhage or other forms of trauma;
    (3) A physiological change such as a vetibular response leading to 
a behavioral change or stress-induced hemorrhagic diathesis, leading in 
turn to tissue damage; and
    (4) Tissue damage directly from sound exposure, such as through 
acoustically mediated bubble formation and growth or acoustic resonance 
of tissues.
    Some of these mechanisms are unlikely to apply in the case of 
impulse sounds. However, there are increasing indications that gas-
bubble disease (analogous to ``the bends''), induced in supersaturated 
tissue by a behavioral response to acoustic exposure, could be a 
pathologic mechanism for the strandings and mortality of some deep-
diving cetaceans exposed to sonar. The evidence for this remains 
circumstantial and associated with exposure to naval mid-frequency 
sonar, not seismic surveys (Cox et al., 2006; Southall et al., 2007).
    Seismic pulses and mid-frequency sonar signals are quite different. 
Sounds produced by airgun arrays are broadband impulses with most of 
the energy below 1 kHz. Typical military mid-frequency sonars operate 
at frequencies of 2 to 10 kHz, generally with a relatively narrow 
bandwidth at any one time. Thus, it is not appropriate to assume that 
there is a direct connection between the effects of military sonar and 
seismic surveys on marine mammals. However, evidence that sonar pulses 
can, in special circumstances, lead (at least indirectly) to physical 
damage and mortality (Balcomb and Claridge, 2001; NOAA and USN, 2001; 
Jepson et al., 2003; Fern[aacute]ndez et al., 2004, 2005a; Cox et al., 
2006) suggests that caution is warranted when dealing with exposure of 
marine mammals to any high-intensity pulsed sound.
    There is no conclusive evidence of cetacean strandings or deaths at 
sea as a result of exposure to seismic surveys, but a few cases of 
strandings in the general area where a seismic survey was ongoing have 
led to speculation concerning a possible link between seismic surveys 
and strandings. Suggestions that there was a link between seismic 
surveys and strandings of humpback whales in Brazil (Engel et al., 
2004) was not well founded based on available data (IAGC, 2004; IWC, 
2007b). 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 (Ewing) was operating a 20 airgun, 8,490 in\3\ array in 
the general area. The link between the stranding and the seismic survey 
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 when conducting seismic 
surveys in areas occupied by beaked whales until more is known about 
effects of seismic surveys on those species (Hildebrand, 2005). 
However, no beaked whales are found within this project area and the 
planned monitoring and mitigation measures are expected to minimize any 
possibility for mortality of other species.

Potential Effects of Chirp Echosounder Signals

    A Knudsen 320BR Plus echosounder will be operated from the source 
vessel at nearly all times during the planned study. Details about the 
equipment are provided in Appendix B of the IHA application. The 
Knudsen 320BR produces sound pulses with lengths up to 24 ms every 0.5 
to approximately 8 s, depending on water depth. The energy in the sound 
pulses emitted by the Chirp echosounder is of moderately high 
frequency. The Knudsen can be operated with either a 3.5 kHz 
transducer, for sub-bottom profiling, or a 12 kHz transducer for 
sounding. The lower frequency (3.5 kHz) transducer is not installed and 
will not be used. The conical beamwidth for the 12 kHz transducer is 
30[deg], and is directed downward.
    Source levels for the Knudsen 320 operating at 12 kHz has been 
measured as a maximum of 215 dB re 1 [mu]Pam. Received levels would 
diminish rapidly with increasing depth. Assuming spherical spreading, 
received level directly below the transducer(s) would diminish to 180 
dB re 1 [mu]Pa at distances of about 56 m (183.7 ft) when operating at 
12 kHz. The 180 dB distance in the horizontal direction (outside the 
downward-directed beam) would be substantially less. 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, and 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.
    Navy sonars that have been linked to avoidance reactions and 
stranding of cetaceans (1) generally are more powerful than the Knudsen 
320BR operating with the 12 kHz transducer,

[[Page 39348]]

(2) have longer pulse duration, and (3) are directed close to 
horizontally vs. downward for the Knudsen 320. The area of possible 
influence of the Chirp echosounder is much smaller--a narrow conical 
beam spreading downward from the vessel. Marine mammals that encounter 
the sounder at close range are unlikely to be subjected to repeated 
pulses because of the narrow width of the beam, and will receive only 
small amounts of pulse energy because of the short pulses.
    Marine mammal communications will not be masked appreciably by the 
Chirp echosounder signals given its relatively low duty cycle, 
directionality, and the brief period when an individual mammal is 
likely to be within its beam. Belugas can, however, hear sounds ranging 
from 1.2 to 120 kHz; their peak sensitivity is approximately 10 to 15 
kHz, overlapping with the 12 kHz signals (Fay, 1988). Some level of 
masking could result for beluga whales in close proximity to the survey 
vessel during brief periods of exposure to the sound. However, masking 
is unlikely to be an issue for beluga whales because belugas are likely 
to avoid survey vessels. The 12 kHz frequency signals will not overlap 
with the predominant low frequencies in baleen whale calls, thus 
reducing potential for masking in this group.
    Marine mammal behavioral reactions to pulsed sound sources from an 
active airgun array are discussed above, and responses to the 
echosounder are likely to be similar to those for other pulsed sources 
if received at the same levels. When the 12 kHz transducer is in 
operation, the behavioral responses to the Knudsen 320BR are expected 
to be similar to those reactions to the active airgun array (as 
discussed above). Because of the lower source level and high 
directionality, NMFS expects animals to be only infrequently exposed to 
higher levels of sound and in short durations, and therefore NMFS does 
not anticipate that exposure to the echosounder will result in a 
``take'' by harassment.
    When the 12 kHz transducer is operating, the pulses are brief and 
concentrated in a downward beam. A marine mammal would be in the beam 
of the echosounder only briefly, reducing its received sound energy. 
Thus, it is unlikely that the chirp echosounder 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 Knudsen 320 BR will be operated simultaneously with the airgun 
array. Many marine mammals will move away in response to the 
approaching higher-power sources of the vessel itself before the 
mammals would be close enough for there to be any possibility of 
effects from the Chirp echosounder (see Appendix D of the IHA 
application).

Potential Effects of Other Acoustic Devices--Chirp SBP Signals

    A Knudsen 3260 SBP will be operated from the St. Laurent in open 
water when the St. Laurent is not working in tandem with the Healy 
during the planned study. The Knudsen's transducer will be towed behind 
the St. Laurent. Details about the equipment are provided in Appendix B 
of the IHA application. The chirp system has a maximum 7.2 kW transmit 
capacity into the towed array and generally operated at 3 to 5 kHz. The 
energy from the towed unit is directed downward by an array of eight 
transducers in a conical beamwidth of 80[deg]. The interval between 
pulses will be no less than one pulse per second. SBPs of that 
frequency can produce sound levels of 200 to 230 dB re 1 [mu]Pa at 1 m 
(Richardson et al., 1995).
    Marine mammal communications will not be masked appreciably by the 
SBP signals given their relatively low duty cycle, directionality of 
the signal and the brief period when an individual mammal is likely to 
be within its beam. In the case of the most odontocetes, the 3 to 5 kHz 
chirp signals do not overlap with the predominant frequencies in their 
calls, which would avoid significant masking. Beluga whale is the only 
odontocete anticipated in the area of the proposed survey. Though 
belugas can hear sounds ranging from 1.2 to 120 kHz, their peak 
sensitivity is approximately 10 to 15 kHz, not overlapping with the 3 
to 5 kHz signals (Fay, 1988). Furthermore, in the case of most baleen 
whales, the low-energy SBP signals do not overlap with the predominant 
low frequencies in the calls, which would reduce potential for masking.
    Marine mammal behavioral reactions to other pulsed sound sources 
are discussed above, and responses to the SBP are likely to be similar 
to those for other pulsed sources if received at the same levels. The 
pulsed signals from the SBP are somewhat weaker than those from the 
airgun array. Therefore, behavioral responses are not expected unless 
marine mammals are very close to the source.
    The pulses from the chirp profiler are brief and directed downward. 
A marine mammal would be in the beam of the SBP only briefly, reducing 
its received sound energy. Thus, it is unlikely that the SBP produces 
pulse levels strong enough to cause hearing impairment or other 
physical injuries even if an animal is (briefly) in a position near the 
surface. It is unlikely that the SBP produces pulse levels strong 
enough to cause hearing impairment or other physical injuries even in 
an animal that is (briefly) in a position near the source. The SBP is 
operated simultaneously with other higher-power acoustic sources, 
including the 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 SBP. In the case of 
mammals that do not avoid the approaching vessel and its various sound 
sources, monitoring and mitigation measures that would be applied to 
minimize effects of other sources would further reduce or eliminate any 
minor effects of the SBP.

Potential Effects of Other Acoustic Devices--MBES Signals

    The Kongsberg EM 122 MBES will be operated from the Healy 
continuously during the planned study. Sounds from the MBES are very 
short pulses, depending on water depth. Most of the energy in the sound 
pulses emitted by the MBES is at frequencies centered at 12 kHz. The 
beam is narrow (approximately 2[deg]) in fore-aft extent and wide 
(approximately 130[deg]) in the cross-track extent. Any given mammal at 
depth near the trackline would be in the main beam for only a fraction 
of a second. Therefore, marine mammals that encounter sound from the 
MBES at close range 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. Similarly, 
Kremser et al. (2005) noted that the probability of a cetacean swimming 
through the area of exposure when an MBES emits a pulse is small. The 
animal would have to pass the transducer at close range and be swimming 
at speeds similar to the vessel in order to be subjected to sound 
levels that could cause TTS. In 2008 and 2009 the St. Laurent and the 
Healy surveyed together with a cooperative strategy similar to that 
proposed for 2010. The director of NOAA's Office of Ocean Exploration 
and Research deemed that the use of the Healy's MBES would not have 
significant impacts on marine mammals of a direct or cumulative nature. 
The U.S. portions of the projects were granted a Categorical Exclusion 
from the need to prepare an EA.
    Navy echosounders that have been linked to avoidance reactions and

[[Page 39349]]

stranding of cetaceans (1) generally are more powerful than the 
Kongsberg EM122 echosounder, (2) generally have a longer pulse duration 
than the Kongsberg EM 122, and (3) are often directed close to 
horizontally vs. more downward for the MBES. The area of possible 
influence of the MBES is much smaller--a narrow band oriented in the 
cross-track direction below the source vessel. Marine mammals that 
encounter the MBES at close range are unlikely to be subjected to 
repeated pulses because of the narrow fore-aft width of the beam, and 
will receive only small amounts of pulse energy because of the short 
pulse. In assessing the possible impacts of a similar MBES system (the 
15.5 kHz Atlas Hydrosweep MBES), Boebel et al. (2004) noted that the 
critical sound pressure level at which TTS may occur is 203.2 dB re 1 
[micro]Pa (rms). The critical region included an area of 43 m (141.1 
ft) in depth, 46 m (151 ft) wide athwartship, and 1 m fore-and-aft 
(Boebel et al., 2004). In the more distant parts of that (small) 
critical region, only slight TTS would be incurred.
    Marine mammal communications will not be masked appreciably by the 
MBES signals given its low duty cycle of the MBES and the brief period 
when an individual mammal is likely to be within its beam. Furthermore, 
the MBES signals (12 kHz) do not overlap with the predominant 
frequencies in the baleen whale calls, further reducing any potential 
for masking in that group.
    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. Also, Navy personnel 
have described observations of dolphins bow-riding adjacent to bow-
mounted mid-frequency sonars during sonar transmissions. During 
exposure to a 21 to 25 kHz ``whale-finding'' sonar with a source level 
of 215 dB re 1 [mu]Pam, gray whales reacted by orienting slightly away 
from the source and being deflected from their course by approximately 
200 m (656 ft) (Frankel, 2005). However, all of those observations are 
of limited relevance to the present situation. Pulse durations from the 
Navy sonars were much longer than those of the MBESs to be used during 
the proposed study, and a given mammal would have received many pulses 
from the naval sonars. During the USGS operations, the individual 
pulses will be very short, and a given marine mammal would not receive 
many of the downward-directed pulses as the vessel passes by.
    Captive bottlenose dolphins and a beluga whale exhibited changes in 
behavior when exposed to 1 s pulsed signals at frequencies similar to 
those that will be emitted by the MBES used by USGS, 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 
either duration or bandwidth as compared with those from a MBES.
    USGS is not aware of any data on the reactions of pinnipeds to 
echosounder sounds at frequencies similar to those of the MBES (12 
kHz). Based on observed pinniped responses to other types of pulsed 
sounds, and the likely brevity of exposure to the MBES, pinniped 
reactions to the echosounder sounds are expected to be limited to 
startle or otherwise brief responses of no lasting consequence to the 
animals.
    Given recent stranding events that have been associated with the 
operation of naval sonar, there is concern that mid-frequency sonar 
sounds can cause serious impacts to marine mammals (see above). 
However, the MBES proposed for use by USGS is quite different from 
sonars used for Navy operations. Pulse duration of the bathymetric 
echosounder is very short relative to the naval sonars. Also, at any 
given location, an individual cetacean or pinniped would be in the beam 
of the MBES for much less time given the generally downward orientation 
of the beam and its narrow fore-aft beamwidth. (Navy sonars often use 
near-horizontally-directed sound.) Those factors would all reduce the 
sound energy received from the bathymetric echosounder relative to that 
from the sonars used by the Navy.
    NMFS believes that the brief exposure of marine mammals to one 
pulse, or small numbers of signals, from the MBES are not likely to 
result in the harassment of marine mammals.

Possible Effects of Helicopter Activities

    It is anticipated that a helicopter will be deployed daily, weather 
permitting to conduct ice reconnaissance as well as to periodically 
transfer personnel between the two vessels. The helicopter will also be 
used to collect spot bathymetry data during operations in Canadian and 
international waters, outside of U.S. waters. The spot soundings will 
be recorded to maximize the area surveyed and the data will be 
collected off the ship's survey lines. A 12 kHz transducer will be 
slung by the helicopter and placed in the water down to a mark affixed 
to the tether. Data will then be logged to a laptop computer in the 
helicopter.
    Levels and duration of sounds received underwater from a passing 
helicopter are a function of the type of helicopter used, orientation 
of the helicopter, the depth of the marine mammal, and water depth. A 
CCG helicopter, a Messerschmitt MBB BO105, will be providing air 
support for this project. Helicopter sounds are detectable underwater 
at greater distances when the receiver is at shallow depths. Generally, 
sound levels received underwater decrease as the altitude of the 
helicopter increases (Richardson et al., 1995). Helicopter sounds are 
audible for much greater distances in air than in water.
    Cetaceans--The nature of sounds produced by helicopter activities 
above the surface of the water do not pose a direct threat to the 
hearing of marine mammals that are in the water; however minor and 
short-term behavioral responses of cetaceans to helicopters have been 
documented in several locations, including the Beaufort Sea (Richardson 
et al., 1985a,b; Patenaude et al., 2002). Cetacean reactions to 
helicopters depend on several variables including the animal's 
behavioral state, activity, group size, habitat, and the flight 
patterns used, among other variables (Richardson et al., 1995). During 
spring migration in the Beaufort Sea, beluga whales reacted to 
helicopter noise more frequently and at greater distances than did 
bowhead whales (38 percent vs. 14 percent of observations, 
respectively). Most reaction occurred when the helicopter passed within 
250 m (820.2 ft) lateral distance at altitudes less than or equal to 
150 m (492.1 ft). Neither species exhibited noticeable reactions to 
single passes at altitudes greater than 150 m (492.1 ft). Belugas 
within 250 m (820.2 ft) of stationary helicopters on the ice with the 
engine showed the most overt reactions (Patenaude et al., 2002). Whales 
were observed to make only minor changes in direction in response to 
sounds produced by helicopters, so all reactions to helicopters were 
considered brief and minor. Cetacean reactions to helicopter 
disturbance are difficult to predict and may range from no reaction at 
all to minor changes in course or (infrequently) leaving the immediate 
area of the activity.
    Pinnipeds--Few systematic studies of pinniped reactions to aircraft 
overflights

[[Page 39350]]

have been completed. Documented reactions range from simply becoming 
alert and raising the head to escape behavior such as hauled-out 
animals rushing to the water. Ringed seals hauled out on the surface of 
the ice have shown behavioral responses to aircraft overflights with 
escape responses most probable at lateral distances greater than 200 m 
(656.2 ft) and overhead distances less than or equal to 150 m (492.1 
ft) (Born et al., 1999). Although specific details of altitude and 
horizontal distances are lacking from many largely anecdotal reports, 
escape reactions to a low flying helicopter (less than 150 m [492.1 ft] 
altitude) can be expected from all four species of pinnipeds 
potentially encountered during the proposed operations. These responses 
would likely be relatively minor and brief in nature. Whether any 
response would occur when a helicopter is at the higher suggested 
operational altitudes (below) is difficult to predict and probably a 
function of several other variables including wind chill, relative wind 
chill, and time of day (Born et al., 1999).
    As mentioned in the previous section, momentary behavioral 
reactions ``do not rise to the level of taking'' (NMFS, 2001). In order 
to limit behavioral reactions of marine mammals during ice 
reconnaissance and spot bathymetry work outside of U.S. waters, the 
helicopter will maintain a minimum altitude of 200 m (656 ft) above the 
sea ice except when taking off, landing, or conducting spot bathymetry. 
Sea-ice landings are not planned at this time.

Possible Effects of Icebreaking Activities

    Icebreakers produce more noise while breaking ice than ships of 
comparable size due, primarily, to the sounds of the propeller 
cavitating (Richardson et al., 1995). Multi-year ice, which is expected 
to be encountered in the northern and eastern areas of the proposed 
survey, is thicker than younger ice. Icebreakers commonly back and ram 
into heavy ice until losing momentum to make way. The highest noise 
levels usually occur while backing full astern in preparation to ram 
forward through the ice. Overall, the noise generated by an icebreaker 
pushing ice was 10 to 15 dB greater than the noise produced by the ship 
underway in open water (Richardson et al., 1995). In general, the 
Arctic Ocean is a noisy environment. Greening and Zakarauskas (1993) 
reported ambient sound levels of up to 180 dB/[mu]Pa\2\/Hz under multi-
year pack ice in the central Arctic pack ice. Little information is 
available about the effect to marine mammals of the increased sound 
levels due to icebreaking.
    Cetaceans--Few studies have been conducted to evaluate the 
potential interference of icebreaking noise with marine mammal 
vocalizations. Erbe and Farmer (1998) measured masked hearing 
thresholds of a captive beluga whale. They reported that the recording 
of a CCG ship, Henry Larsen, ramming ice in the Beaufort Sea, masked 
recordings of beluga vocalizations at a noise to signal pressure ratio 
of 18 dB, when the noise pressure level was eight times as high as the 
call pressure. Erbe and Farmer (2000) also predicted when icebreaker 
noise would affect beluga whales through software that combined a sound 
propagation model and beluga whale impact threshold models. They again 
used the data from the recording of the Henry Larsen in the Beaufort 
Sea and predicted that masking of beluga vocalizations could extend 
between 40 and 71 km (24.9 and 44.1 mi) near the surface. Lesage et al. 
(1999) report that beluga whales changed their call type and call 
frequency when exposed to boat noise. It is possible that the whales 
adapt to the ambient noise levels and are able to communicate despite 
the sound. Given the documented reaction of belugas to ships and 
icebreakers it is highly unlikely that beluga whales would remain in 
the proximity of vessels where vocalizations would be masked.
    Beluga whales have been documented swimming rapidly away from ships 
and icebreakers in the Canadian high Arctic when a ship approaches to 
within 35 to 50 km (21.4 to 31.1 mi), and they may travel up to 80 km 
(49.7 mi) from the vessel's track (Richardson et al., 1995). It is 
expected that belugas avoid icebreakers as soon as they detect the 
ships (Cosens and Dueck, 1993). However, the reactions of beluga whales 
to ships vary greatly and some animals may become habituated to higher 
levels of ambient noise (Erbe and Darmber, 2000).
    There is little information about the effects of icebreaking ships 
on baleen whales. Migrating bowhead whales appeared to avoid an area 
around a drill site by greater than 25 km (15.5 mi) where an icebreaker 
was working in the Beaufort Sea. There was intensive icebreaking daily 
in support of the drilling activities (Brewer et al., 1993). Migrating 
bowheads also avoided a nearby drill site at the same time of year 
where little icebreaking was being conducted (LGL and Greeneridge, 
1987). It is unclear as to whether the drilling activities, icebreaking 
operations, or the ice itself might have been the cause for the whales' 
diversion. Bowhead whales are not expected to occur in the proximity of 
the proposed action area.
    Pinnipeds--Brueggeman et al. (1992) reported on the reactions of 
seals to an icebreaker during activities at two prospects in the 
Chukchi Sea. Reactions of seals to the icebreakers varied between the 
two prospects. Most (67 percent) seals did not react to the icebreaker 
at either prospect. Reaction at one prospect was greatest during 
icebreaking activity followed by general vessel activity (running/
maneuvering/jogging) and was 0.23 km (0.14 mi) of the vessel and lowest 
for animals beyond 0.93 km (0.58 mi). At the second prospect however, 
seal reaction was lowest during icebreaking activity with higher and 
similar levels of response during general (non-icebreaking) vessel 
operations and when the vessel was at anchor or drifting. The frequency 
of seal reaction generally declined with increasing distance from the 
vessel except during general vessel activity where it remained 
consistently high to about 0.46 km (0.29 mi) from the vessel before 
declining.
    Similarly, Kanik et al. (1980) found that ringed and harp seals 
often dove into the water when an icebreaker was breaking ice within 1 
km (0.6 mi) of the animals. Most seals remained on the ice when the 
ship was breaking ice 1 to 2 km (0.6 to 1.2 mi) away.

Estimated Take of Marine Mammals by Incidental Harassment

    All anticipated takes would be ``takes by Level B harassment,'' 
involving temporary changes in behavior. The proposed monitoring and 
mitigation measures are expected to minimize the possibility of 
injurious takes or mortality. However, as noted earlier, there is no 
specific information demonstrating that injurious ``takes'' or 
mortality would occur even in the absence of the planned monitoring and 
mitigation measures. NMFS believes, therefore, that injurious take or 
mortality to the affected species marine mammals is extremely unlikely 
to occur as a result of the specified activities within the specified 
geographic area for which USGS seeks the IHA. The sections below 
describe methods to estimate ``take by harassment,'' and present 
estimates of the numbers of marine mammals that could be affected 
during the proposed seismic study in the Arctic Ocean. The estimates of 
``take by harassment,'' are based on data obtained during marine mammal 
surveys in and near the Arctic Ocean by Stirling et al. (1982), 
Kingsley (1986), Moore et al. (2000b), Haley and Ireland (2006), Haley 
(2006), GSC unpublished data (2008), and Mosher et al. (2009), Bowhead 
Whale Aerial Survey Program (BWASP), and on estimates of the sizes

[[Page 39351]]

of the areas where effects could potentially occur. In some cases these 
estimates were made from data collected from regions and habitats that 
differed from the proposed project area.
    Detectability bias, quantified in part by [fnof](0), is associated 
with diminishing sightability with increasing lateral distance from the 
trackline. Availability bias (g[0]) refers to the fact that there is 
less than 100 percent probability of sighting an animal that is present 
along the survey trackline. Some sources of densities used below 
included these correction factors in their reported densities. In other 
cases the best densities used below included these correction factors 
in their reported densities. In other cases the best available 
correction factors were applied to reported results when they had not 
been included in the reported data (Moore et al., 2000b). Adjustments 
to reported population or density estimates were made on a case by case 
basis to take into account differences between the source data and the 
general information on the distribution and abundance of the species in 
the proposed project area.
    Although several systematic surveys of marine mammals have been 
conducted in the southern Beaufort Sea, few data (systematic or 
otherwise) are available on the distribution and numbers of marine 
mammals in the northern Beaufort Sea or offshore water of the Arctic 
Ocean. The main sources of distributional and numerical data used in 
deriving the estimates are described in the next subsection. Both 
``maximum estimates'' as well as ``best estimates'' of marine mammal 
densities (see Table 5 of the IHA application) and the numbers of 
marine mammals potentially exposed to underwater sound (see Table 6 of 
the IHA application) were calculated as described below. The best (or 
average) estimate is based on available distribution and abundance data 
and represents the most likely number of animals that may be 
encountered during the survey, assuming no avoidance of the airguns or 
vessel. The maximum estimate is either the highest estimate from 
applicable distribution and abundance data or the average estimate 
increased by a multiplier intended to produce a very conservative 
(over) estimate of the number of animals that may be present in the 
survey area. There is some uncertainty about how representative the 
available data are and the assumptions used below to estimate the 
potential ``take by harassment.'' However, the approach used here is 
accepted by NMFS as the best available at this time.
    USGS has calculated exposures to marine mammals within U.S. waters 
only. After the St. Laurent (a Canadian icebreaker) exits U.S. waters, 
their activities no longer fall under the jurisdiction of the U.S. or 
the MMPA.
    The following estimates are based on a consideration of the number 
of marine mammals that might be disturbed appreciably over the 
approximately 806 line km (501 mi) of seismic surveys within U.S. 
waters across the Arctic Ocean. An assumed total of 1,007.5 km (626 mi) 
of trackline includes a 25 percent allowance over and above the planned 
approximately 806 km to allow for turns, lines that might have to be 
repeated because of poor data quality, or for minor changes to the 
survey design.
    The anticipated radii of influence of the lower energy sound 
sources including Chirp echosounder (on the St. Laurent) and 
bathymetric echosounder (on the Healy) are less than that for the 
airgun configuration. It is assumed that during simultaneous operations 
of the airgun array and echosounder, any marine mammals close enough to 
be affected by the sounder would already be affected by the airguns. 
However, whether or not the airguns are operating simultaneously with 
the echosounder, marine mammals are expected to exhibit no more than 
short-term and inconsequential responses to the sounder given its 
characteristics (e.g., narrow downward-directed beam) and other 
considerations described in the IHA application. Similar responses are 
expected from marine mammals exposed to the Healy's bathymetric 
profiler. Such reactions are not considered to constitute ``taking'' as 
defined by NMFS (NMFS, 2001). Therefore, no additional allowance is 
included for animals that might be exposed to sound sources other than 
the airguns.

Marine Mammal Density Estimates

    Numbers of marine mammals that might be present and potentially 
disturbed are estimated based on available data about marine mammal 
distribution and densities in the Arctic Ocean study area during the 
summer. ``Take by harassment'' is calculated by multiplying expected 
densities of marine mammals likely to occur in the survey area by the 
area of water potentially ensonified to sound levels >=160 dB re 1 
[mu]Pa (rms) for the airgun operations and >=120 dB re 1 [mu]Pa (rms) 
for icebreaking activities. Estimates for icebreaking are based on a 
consideration of the number of marine mammals that might be disturbed 
appreciably over the approximately 3,102 to 3,372 line km (1,927.5 to 
2,095.3 mi) of icebreaking that may occur during the proposed project. 
This section provides descriptions of the estimated densities of marine 
mammals that may occur in the proposed survey area. The area of water 
that may be ensonified to the indicated sound level is described 
further below. There is no evidence that avoidance at received sound 
levels >=160 dB would have significant effects on individual animals or 
that the subtle changes in behavior or movements would rise to the 
level of taking according to guidance by NMFS (NMFS, 2001).
    Some surveys of marine mammals have been conducted near the 
southern end of the proposed project area, but few data are available 
on the species and abundance of marine mammals in the northern Beaufort 
Sea and the Arctic Ocean. No published densities of marine mammals are 
available for the region of the proposed survey (including between 
74[deg] and 84[deg] North where the Healy will be breaking ice outside 
U.S. waters), although vessel-based surveys through the general area in 
2005, 2006, 2008, and 2009 encountered few marine mammals. A total of 
two polar bears, 36 seals, and a single beluga whale sighting(s) were 
recorded along approximately 2,299 km (1,429 mi) of monitored trackline 
between 71[deg] North and 74[deg] North (Haley and Ireland, 2006; 
Haley, 2006; GSC unpublished data, 2008; Mosher et al., 2009). PSOs 
recorded 268 sightings of 291 individual seals along approximately 
21,322 km (13,248.9 mi) of monitored trackline between 74[deg] and 
84[deg] North (Haley and Ireland, 2006; Haley, 2006; GSC unpublished 
data, 2008; Mosher et al., 2009). No cetaceans were observed during the 
surveys between 74[deg] and 84[deg] North. Given the few sightings of 
marine mammals along the 21,322 km (13,248.9 mi) vessel trackline in 
previous years, USGS estimate that the densities of marine mammals 
encountered while breaking ice will be 1/10 of the estimated densities 
of marine mammals encountered within the ice margin habitat described 
in the original application.
    Given that the survey lines within U.S. waters extend from 
latitudes 71[deg] to 74[deg] North, it is likely that seismic 
operations will be conducted in both open-water and sea-ice conditions. 
Because densities of marine mammals often differ between open-water and 
pack-ice areas, the likely extent of the pack-ice at the time of the 
survey was estimated. Images of average monthly sea ice concentration 
for August from 2005 through 2009, available from the National Snow and 
Ice Data Center

[[Page 39352]]

(NISDC), were used to identify 74[deg] North latitude as a reasonable 
ice-edge boundary applicable to the proposed study period and location. 
Based on these satellite data, the majority of the survey in U.S. 
waters will be conducted in open water and unconsolidated pack ice, in 
the southern latitudes of the survey area. This region will include the 
ice margin where the highest densities of cetaceans and pinnipeds are 
likely to be encountered. The proposed survey lines within U.S. waters 
reach approximately 74.10[deg] North, extending within the estimated 
ice-edge boundary for August, 2010 by approximately 19 km (10 mi). This 
comprises less than 3 percent of the total trackline within U.S. 
waters. USGS has divided the survey effort between the two habitat 
zones of open water and ice margin based on the 2005 to 2009 NSIDC 
satellite data described above and the planed location of the 
tracklines. NSIDC data from 2005 to 2009 suggests little ice will be 
present south of 74[deg] North, although data from the 2009 cruise 
(Moser et al., 2009) shows that inter-annual variability could result 
in a greater amount of ice being encountered than expected. As a 
conservative measure, USGS estimated that, within U.S. waters, 80 
percent of the survey tracklines will occur in open water and 20 
percent of the tracklines will occur within the ice margin.
    The NSIDC (2009) reported that more Arctic sea ice cover in 2009 
remained after the summer than in the record-setting low years of 2007 
and 2008. USGS expects that sea ice density and extent in 2010 will be 
closer to the density and extent of sea ice in 2009 rather than the 
record-setting low years of 2007 and 2008. All animals observed during 
the 2009 survey (Mosher et al., 2009) were north of the proposed 
seismic survey area, i.e., north of 74[deg] North.
    Cetaceans--Average and maximum densities for each cetacean species 
or species group reported to occur in U.S. waters of the Arctic Ocean, 
within the study area, are presented in Table 5 of the IHA application. 
Densities were calculated based on the sightings and effort data from 
available survey reports. No cetaceans were observed during surveys 
near the proposed study area in August/September, 2005 (Haley and 
Ireland, 2006), August, 2006 (Haley, 2006), August/September, 2008 (GSC 
unpublished data, 2008) or August/September, 2009 (Mosher et al., 
2009).
    Seasonal (summer and fall) differences in cetacean densities along 
the north coast of Alaska have been documented by Moore et al. (2000b). 
The proposed survey will be conducted in U.S. waters from approximately 
August 6 to 12, 2010 and is considered to occur during the summer 
season.
    The summer beluga density (see Table 5 of the IHA application) was 
based on 41 sightings along 9,022 km (5,606 mi) of on-transect effort 
that occurred over water greater than 2,000 m (6,561.7 ft) during the 
summer in the Beaufort Sea (Moore et al., 2000b; see Table 2 of the IHA 
application). A mean group size of 2.8 derived from BWASP data of 
August beluga sightings in the Beaufort Sea in water depths greater 
than 2,000 m was used in the density calculation. A [fnof](0) value of 
2.326 from Innes et al. (1996) and a g(0) value of 0.419 from Innes et 
al. (1996) and Harwood et al. (1996) were also used in the density 
computation. The CV associated with group size was used to select an 
inflation factor of 2 to estimate the maximum density that may occur in 
the proposed study area within U.S. waters. Most Moore et al. (2000b) 
sightings were south of the proposed seismic survey. However, Moore et 
al. (2000b) found that beluga whales were associated with both light (1 
to 10 percent) and heavy (70 to 100 percent) ice cover. Five of 23 
beluga whales that Suydam et al. (2005) tagged in Kaseglauk Lagoon 
(northeast Chukchi Sea) traveled to 79 to 80[deg] North into the pack 
ice and within the region of the proposed survey. These and other 
tagged whales moved into areas as far as 1,100 km (594 nmi) offshore 
between Barrow and the Mackenzie River delta, spending time in water 
with 90 percent ice coverage. Therefore, we applied the observed 
density calculated from the Moore et al. (2000b) sightings as the 
average density for both ``open water'' and ``ice margin'' habitats. 
Because no beluga whales were sighted during surveys in the proposed 
survey area (Harwood et al., 2005; Haley and Ireland, 2006; Haley, 
2006; GSC unpublished data, 2008; and Mosher et al., 2009) the 
densities in Table 5 of the IHA application are probably higher than 
densities likely to be encountered.
    By the time the survey begins in early August, most bowhead whales 
have typically traveled east of the proposed project area to summer in 
the eastern Beaufort Sea and Amundsen Gulf. Industry aerial surveys of 
the continental shelf near Camden Bay in 2008 recorded eastward 
migrating bowhead whales until July 12 (Lyons and Christie, 2009). No 
bowhead sightings were recorded again despite continued flights until 
August 19, 2010. A summer bowhead whale density was derived from 9,022 
km (5,606 mi) of summer (July/August) aerial survey effort reported by 
Moore et al. (2000b) in the Alaska Beaufort Sea during which six 
sightings of bowhead whales were documented in water greater than 2,000 
m (6,561.7 ft). A mean group size of bowhead whale sightings in 
September, in waters greater than 2,000 m deep, was calculated to be 
1.14 (CV= 0.4) from BWASP data. A [fnof](0) value of 2.33 and g(0) 
value of 0.073, both from Thomas et al. (2002) were used to estimate a 
summer density for bowhead whales of 0.0122 whales/km\2\. This density 
falls within the range of densities, i.e., 0.0099 to 0.0717 whales/
km\2\, reported by Lyons and Christie (2009) based on data from three 
July, 2008 surveys.
    Treacy et al. (2006) reported that in years of heavy ice 
conditions, bowhead whales occur farther offshore than in years of 
light to moderate ice. NSIDC (2009) reported that September, 2009 had 
the third lowest sea ice extent since the start of their satellite 
records in 1979. The extent of sea ice at the end of the 2009 Arctic 
summer, however, was greater than in 2007 or 2008. USGS does not expect 
2010 to be a heavy ice year during which bowhead whales might occur 
farther offshore in the area of the proposed survey. During the lowest 
ice-cover year on record (2007), BWASP reported no bowhead whale 
sightings in the greater than 2,000 m depth waters far offshore. 
Because few bowhead whales have been documented in the deep offshore 
waters of the proposed survey area, half of the bowhead whale density 
estimate from size and standard error reported in Thomas et al. (2002) 
for [fnof](0) and g(0) correction factors suggest that an inflation 
factor of two is appropriate for estimating the maximum density from 
the average density. NSIDC did not forecast that 2010 would be a heavy 
ice year and USGS anticipates that bowheads will remain relatively 
close to shore, and in areas of light ice coverage. Therefore, USGS has 
applied the same density for bowheads to the open-water and ice-margin 
categories. Bowhead whales were not sighted during recent surveys in 
the Arctic Ocean (Haley and Ireland, 2006; Haley, 2006; GSC unpublished 
data, 2008; Mosher et al., 2009), suggesting that the bowhead whale 
densities shown in Table 5 are likely higher than actual densities in 
the survey area.
    For other cetacean species that may be encountered in the Beaufort 
Sea, densities are likely to be very low in the summer when the survey 
is scheduled. Fin and humpback whales are unlikely to occur in the 
Beaufort Sea. No gray whales were observed in the Beaufort Sea by Moore 
et al. (2000b) during summer aerial surveys in water greater than 2,000 
m. Gray whales were not recorded in water greater than 2,000 m by the 
BWASP during August in 29

[[Page 39353]]

years of survey operation. Harbor porpoises are not expected to be 
present in large numbers in the Beaufort Sea during the fall although 
small numbers may be encountered during the summer. Neither gray whales 
nor harbor porpoises are likely to occur in the far-offshore waters of 
the proposed survey area (Table 5 of the IHA application). Narwhals are 
not expected to be encountered within the survey area although a few 
individuals could be present if ice is nearby. Because these species 
occur so infrequently in the Beaufort Sea, little to no data are 
available for the calculation of densities. Minimal cetacean densities 
have therefore been assigned to these three species for calculation 
purposes and to allow for chance encounters (see Table 5 of the IHA 
application). Those densities include ``0'' for the average and 0.0001 
individuals/km\2\ for the maximum.
    Pinnipeds--Extensive surveys of ringed and bearded seals have been 
conducted in the Beaufort Sea, but most surveys were conducted over the 
landfast ice during aerial surveys, and few seal surveys have occurred 
in open water or in the pack ice. Kingsley (1986) conducted ringed seal 
surveys of the offshore pack ice in the central and eastern Beaufort 
Sea during the late spring (late June). These surveys provide the most 
relevant information on densities of ringed seals in the ice margin 
zone of the Beaufort Sea. The density estimate in Kingsley (1986) was 
used as the average density of ringed seals that may be encountered in 
the ice-margin area of the proposed survey (see Table 5 of the IHA 
application). The average density was multiplied by four to estimate 
maximum density, as was done for all seal species likely to occur 
within the survey area. Ringed seals are closely associated with sea 
ice therefore the ice-margin densities were multiplied by a factor of 
0.75 to estimate a summer open-water ringed-seal density for locations 
with water depth greater than 2,000 m (6,561.7 ft).
    Densities of bearded seals were estimated by multiplying the ringed 
seal densities by 0.051 based on the proportion of bearded seals to 
ringed seals reported in Stirling et al., (1982; see Table 6-3 of IHA 
application). Because bearded seals are associated with the pack ice 
edge and shallow water, their estimated summer ice-margin density was 
also multiplied by a factor of 0.75 for the open-water density 
estimate. Minimal values were used to estimate spotted seal densities 
because they are uncommon offshore in the Beaufort Sea and are not 
likely to be encountered.
    Numbers of marine mammals that might be present and potentially 
disturbed are estimated below based on available data about marine 
mammal distribution and densities in the three different habitats 
during the summer as described in Table 5 of the IHA application.
    The number of individuals of each species potentially exposed to 
received levels greater than or equal to 160 dB re 1 [micro]Pa (rms) 
(for seismic airgun operations) or 120 dB re 1 [mu]Pa (rms) (for 
icebreaking) was estimated by multiplying
     The anticipated area to be ensonified to the specified 
sound level in both open water, the ice margin, and polar pack by
     The expected species density.
    Some of the animals estimated to be exposed to sound levels greater 
than or equal to 160 dB re 1 [mu]Pa (rms) or 120 dB re 1 [mu]Pa (rms), 
particularly migrating bowhead whales, might show avoidance reactions 
before actual exposure to this sound level (see Appendix D of the IHA 
application). Thus, these calculations actually estimate the number of 
individuals potentially exposed to greater than or equal to 160 dB 
(rms) or 120 dB re 1 [micro]Pa (rms) that would occur if there were no 
avoidance of the area ensonified to that level.

Estimated Area Exposed to >= 160 dB (rms)

    The area of water potentially exposed to received levels greater 
than or equal to 160 dB by the proposed operations was calculated by 
multiplying the planned trackline distance within U.S. waters by the 
cross-track distance of the sound propagation. The airgun array of two 
500 in\3\ and one 150 in\3\ G-airguns that will be used for the 
proposed 2010 survey within U.S. waters was measured during a 2009 
project in the Arctic Ocean. The propagation experiment took place at 
74[deg] 50.4' North; 156[deg] 34.31' West, in 3,863 m (12,674 ft) of 
water. The location was near the northern end of the two proposed 
survey lines in U.S. waters. USGS expects the sound propagation by the 
airgun array in the planned 2010 survey will be the same as that 
measured in 2009, because of the similar water depths and relative 
locations of the test site and proposed survey area. The greater than 
or equal to 160 dB (rms) sound level radius was estimated to be 
approximately 2,500 m (8,202.1 ft) based on modeling of the 0 to peak 
energy of the airgun array (Roth and Schmidt, 2010). The 0 to peak 
values were corrected to rms by subtracting 10 dB.
    Closely spaced survey lines and large cross-track distances of the 
greater than or equal to 160 dB radii can result in repeated exposure 
of the same area of water. Excessive amounts of repeated exposure can 
lead to overestimation of the number of animals potentially exposed 
through double counting. The trackline for the proposed USGS survey in 
U.S. waters, however, covers a large geographic area without adjacent 
tracklines and the potential for multiple or repeated exposure is 
unlikely to be a concern.
    The USGS 2010 geophysical survey is planned to occur approximately 
108 km (67.1 mi) offshore, along approximately 806 km (501 mi) of 
survey lines in U.S. waters, during the first half of August exposing a 
total of approximately 4,109 km\2\ (1,586.5 mi\2\) of water to sound 
levels of greater than or equal to 160 dB (rms).USGS included an 
additional 25 percent allowance over and above the planned tracklines 
within U.S. waters to allow for turns, lines that might have to be 
repeated because of poor data quality, or for minor changes to the 
survey design. The resulting estimate of 5,136.5 km\2\ (1,983.2 mi\2\) 
was used to estimate the numbers of marine mammals exposed to 
underwater sound levels greater than or equal to 160 dB (rms).
    Based on the operational plans and marine mammal densities 
described in Table 5 of the IHA application, the estimates of marine 
mammals potentially exposed to sounds greater than or equal to 160 dB 
(rms) in the proposed survey area within U.S. waters are presented in 
Table 6 of the IHA application. For the common species, the requested 
numbers are calculated as described above and based on the average 
densities from the data reported in the different studies mentioned 
above. For less common species, estimates were set to minimal values to 
allow for chance encounters. Discussion of the number of potential 
exposures is summarized by species in the following subsections.
    Cetaceans--Based on density estimates and area ensonified, one 
endangered cetacean species (bowhead whale) is expected to be exposed 
to received levels greater than or equal to 160 dB unless bowheads 
avoid the survey vessel before the received levels reach 160 dB. 
Migrating bowheads are likely to do so, though many of the bowheads 
engaged in other activities, particularly feeding and socializing may 
not. The USGS estimate of the number of bowhead whales potentially 
exposed to sound levels greater than or equal to 160 dB in the portion 
of the survey area in U.S. waters in between 31 and 63 (see Table 6 of 
the IHA application). Although take was calculated based on

[[Page 39354]]

density estimates in the proposed action area, the proposed seismic 
survey will be conducted during the fall migration for bowhead whales, 
but at locations starting at greater than 185.2 km (100 nmi) offshore, 
well north of the known bowhead migration corridor and well beyond 
distances (20 to 30 km [12.4 to 18.6], Miller et al., 1999; Richardson 
et al., 1999) known to potentially effect this species. Other 
endangered cetacean species that may be encountered in the area are fin 
and humpback whales; both are unlikely to be exposed given their 
minimal density in the area.
    The only other cetacean species likely to occur in the proposed 
survey area is the beluga whale. Average (best) and maximum estimates 
of the number of exposures of belugas to sound levels greater than or 
equal to 160 dB (rms) are 182 and 364, respectively. Estimates for 
other cetacean species are minimal (see Table 6 of the IHA 
application).
    Pinnipeds--The ringed seal is the most widespread and abundant 
pinniped in ice-covered arctic waters, and there is a great deal of 
annual variation in abundance and distribution of these marine mammals. 
Ringed seals account for the vast majority of marine mammals expected 
to be encountered, and hence exposed to airgun sounds with received 
levels greater than or equal to 160 dB (rms) during the proposed marine 
seismic survey. The average (best) and maximum number of exposures of 
ringed seals to sound levels greater than or equal to 160 dB (rms) were 
estimated to be 1,031 and 4,126, respectively.
    Two additional pinniped species (other than the Pacific walrus) are 
likely to occur in the proposed project area. The average and maximum 
numbers of exposures of bearded seals to sound levels greater than or 
equal to 160 dB (rms) were estimated to be 53 and 210, respectively. 
The ribbon seal is unlikely to be encountered in the survey area, but a 
chance encounter could occur.

Estimated Area Exposed to >= 120 dB (rms)

    The area potentially exposed to received levels greater than or 
equal to 120 dB (rms) due to icebreaking operations was estimated by 
multiplying the anticipated trackline distance breaking ice by the 
estimated cross-track distance to received levels of 120 dB caused by 
icebreaking.
    In 2008, acousticians from Scripps Institution of Oceanography 
Marine Physical Laboratory and University of New Hampshire Center for 
Coastal and Ocean Mapping conducted measurements of SPLs of Healy 
icebreaking under various conditions (Roth and Schmidt, 2010). The 
results indicated that the highest mean SPL (185 dB [rms]) was measured 
at survey speeds of 4 to 4.5 knots in conditions of 5/10 ice and 
greater. Mean SPL under conditions where the ship was breaking heavy 
ice by backing and ramming was actually lower (180 dB). In addition, 
when backing and ramming, the vessel is essentially stationary, so the 
ensonified area is limited for a short period (on the order of minutes 
to tens of minutes) to the immediate vicinity of the boat until the 
ship breaks free and once again makes headway.
    Although the report by Roth and Schmidt has not yet been reviewed 
externally nor peer-reviewed for publication, the SPL results reported 
are consistent with previous studies (Thiele, 1981, 1988; LGL and 
Greenridge, 1986; Richardson et al., 1995).
    The existing threshold for Level B harassment for continuous sounds 
is a received sound level of 120 dB SPL. Using a spherical spreading 
model, a source level of 185 dB decays to 120 dB in about 1,750 m 
(5,741.5 ft). This model is corroborated by Roth and Schmidt (2010). 
Therefore, as the ship travels through the ice, a swath 3,500 m (11,483 
ft) wide would be subjected to sound levels greater than or equal to 
120 dB (rms). This results in the potential exposure of 11,802 km\2\ 
(4,557.8 mi\2\) to sounds greater than or equal to 120 dB (rms) from 
icebreaking.
    Based on the operational plans and marine mammal densities 
described above, the estimates of marine mammals exposed to sounds 
greater than or equal to 120 dB (rms) during the maximum estimation of 
icebreaking outside of U.S. waters (3,372 km [2,095.3 mi]) are 
presented in Table Add-4 of the IHA application. For the common marine 
mammal species, the requested numbers are calculated as described above 
and based on the average densities from the data reported in the 
different studies mentioned above. For less common species, estimates 
were set to minimal values to allow for chance encounters.
    Based on models, bowhead whales likely would respond to the sound 
of the icebreakers at distances of 2 to 25 km (1.2 to 15.5 mi) from the 
icebreakers (Miles et al., 1987). This study predicts that roughly half 
of the bowhead whales show avoidance responses to an icebreaker 
underway in open water at a range of 2 to 12 km (1.3 to 7.5 mi) when 
the sound-to-noise ratio is 30 dB (rms). The study also predicts that 
roughly half of the bowhead whales would show avoidance response to an 
icebreaker pushing ice at a range of 4.6 to 6.2 km (2.9 to 12.4 mi) 
when the sound-to-noise ratio is 30 dB.
    Richardson et al. (1995b) found that bowheads migrating in the 
nearshore lead during the spring migration often tolerated exposure to 
playbacks of recorded icebreaker sounds at received levels up to 20 dB 
or more above the natural ambient noise levels at corresponding 
frequencies. The source level of an actual icebreaker is much higher 
than that of the projectors (projecting the recorded sound) used in 
this study (median difference 34 dB over the frequency range 40 Hz to 
6.3 kHz). Over the two season period (1991 and 1994) when icebreaker 
playbacks were attempted, an estimated 93 bowheads (80 groups) were 
seen near the ice camp when the projectors were transmitting icebreaker 
sounds into the water, and approximately 158 bowheads (116 groups) were 
seen near there during quiet periods. Some bowheads diverted from their 
course when exposed to levels of projected icebreaker sound greater 
than 20 dB above the natural ambient noise level in the \1/3\ octave 
band of the strongest icebreaker noise. However, not all bowheads 
diverted at that sound-to-noise ratio, and a minority of whales 
apparently diverted at a lower sound-to-noise ratio. The study 
concluded that exposure to a single playback of variable icebreaker 
sounds can cause statistically, but probably not biologically 
significant effects on movements and behavior of migrating whales in 
the lead system during the spring migration east of Point Barrow, 
Alaska. The study indicated the predicted response distances for 
bowheads around an actual icebreaker would be highly variable; however, 
for typical traveling bowheads, detectable effects on movements and 
behavior are predicted to extend commonly out to radii of 10 to 30 km 
(6.2 to 18.6 mi). Predicting the distance a whale would respond to an 
icebreaker like the Healy is difficult because of propagation 
conditions and ambient noise varies with time and with location. 
However, because the closest survey activities and icebreaking are 
approximately 116 km (72.1 mi) away and are of limited duration (5 
days), and the next closest survey activities are 397 km (246.7 mi) 
away to the north and west in the Arctic ocean, NMFS does not 
anticipate that icebreaking activities would have biologically 
significant effects on the movements and behavior of bowhead whales.

[[Page 39355]]



 Table 6--The Estimates of the Possible Numbers of Marine Mammals Exposed to Sound Levels Greater Than or Equal
to 120 dB (rms) (for Icebreaking) or 160 dB (rms) (for Seismic Airgun Operations) During USGS's Proposed Seismic
    Survey in U.S. Waters in the Northern Beaufort Sea and Arctic Ocean, in August, 2010. Received Levels are
Expressed in dB re 1 [mu]Pa (rms) (Averaged Over Pulse Duration), Consistent With NMFS' Practice. Not All Marine
  Mammals Will Change Their Behavior When Exposed to These Sound Levels, but Some May Alter Their Behavior When
  Levels Are Lower (See Text). See Tables 4 to 5 and Add-3 and Add-4 in USGS's Application for Further Detail.
----------------------------------------------------------------------------------------------------------------
                                              Number of         Number of
                                             individuals       individuals                         Approximate
                                          exposed (best) 1   exposed (max) 2                       percent of
                 Species                   open water, ice   open water, ice    Total (best)        regional
                                            margin, polar     margin, polar                     population best)
                                                pack              pack                                  2
----------------------------------------------------------------------------------------------------------------
Odontocetes.............................               146               291
Beluga whale............................                36                73               224              0.57
(Delphinapterus leucas).................                42                84
Narwhal.................................                 0                 1
(Monodon monocerus).....................                 0                 1                 0                 0
                                                         0                 1
Killer whale............................                 0                 0
(Orcinus orca)..........................                 0                 0                 0                 0
                                                         0                 1
Harbor porpoise.........................                 0                 0
(Phocoena phocoena).....................                 0                 0                 0                 0
                                                         0                 1
Mysticetes..............................                25                50
Bowhead whale...........................                 6                13                38              0.36
(Balaena mysticetus)....................                 7                 1
Eastern Pacific gray whale..............                 0                 0
(Eschrichtius robustus).................                 0                 0                 0                 0
                                                         0                 1
Minke whale.............................                 0                 0
(Balaenoptera acutorostrata)............                 0                 0                 0                 0
                                                         0                 1
Fin whale...............................                 0                 0
(Balaenoptera physalus).................                 0                 0                 0                 0
                                                         0                 1
Humpback whale..........................                 0                 0
(Megaptera novaeangliae)................                 0                 0                 0                 0
                                                         0                 0
Pinnipeds...............................                39               158
Bearded seal............................                13                53                67              0.02
(Erignathus barbatus)...................                15                60
Spotted seal............................                 0                 2
(Phoca largha)..........................                 0                 0                 0                 0
                                                         0                 0
Ringed seal.............................               774             3,094
(Pusa hispida)..........................               258             1,031             1,328              7.38
                                                       296             1,185
Ribbon seal (Histriophoca fasciata).....              N.A.              N.A.              N.A.              N.A.
Pacific walrus (Odobenus rosmarus                     N.A.              N.A.              N.A.              N.A.
 divergens).............................
Carnivores
    Polar bear (Ursus maritimus marinus)              N.A.              N.A.              N.A.              N.A.
----------------------------------------------------------------------------------------------------------------
N.A.--Data not available or species status was not assessed.
1 Best estimate and maximum density estimates are from Table 5 and Table Add-3 of USGS's application.
2 Regional population size estimates are from Table 4.

    Conclusions--Bowhead whales are considered by NMFS to be disturbed 
after exposure to underwater sound levels greater than or equal to 160 
dB (rms) for impulse sources and 120 dB (rms) for continuous sources. 
The relatively small airgun array proposed for use in this survey 
limits the size of the 160 dB (rms) EZ around the vessel and is not 
expected to result in any bowhead whale exposures to underwater sound 
levels sufficient to reach the disturbance criterion as defined by 
NMFS.
    Odontocete reactions to seismic energy pulses are usually assumed 
to be limited to lesser distances from the airgun(s) than are those of 
mysticetes, probably in part because odontocete low-frequency hearing 
is assumed to be less sensitive than that of mysticetes. However, at 
least when in the Canadian Beaufort Sea in summer, belugas appear to be 
fairly responsive to seismic energy, with few being sighted within 10 
to 20 km (6.2 to 12.4 mi) of seismic vessels during aerial surveys 
(Miller et al., 2005). Belugas will likely occur in small numbers in 
the project area within U.S. waters during the survey period. Most 
belugas will likely avoid the vicinity of the survey activities and few 
will likely be affected.
    Taking into account the mitigation measures that are planned, 
effects on cetaceans are generally expected to be restricted to 
avoidance of a limited area around the survey operation and short-

[[Page 39356]]

term changes in behavior, falling within the MMPA definition of ``Level 
B harassment.'' Furthermore, the estimated numbers of animals 
potentially exposed to sound levels sufficient to cause appreciable 
disturbance are very low percentages of the population sizes in the 
Bering-Chukchi-Beaufort Seas.
    Based on the >= 160 dB disturbance criterion, the best estimates of 
the numbers of cetacean exposures to sounds >= 160 dB re 1 [mu]Pa (rms) 
represent less than one percent of the populations of each species in 
the Chukchi Sea and adjacent waters. For species listed as Endangered 
under the ESA, USGS estimates suggest it is unlikely that fin whales or 
humpback whales will be exposed to received levels >= 160 dB and/or >= 
120 dB, but that approximately 38 bowheads (0.36 percent of the 
regional population) may be exposed at this level. The latter is less 
than one percent of the Bering-Chukchi-Beaufort population of greater 
than 14,247 assuming 3.4 percent population growth from the 2001 
estimate of greater than 10,545 animals (Zeh and Punt, 2005). NMFS does 
not anticipate bowhead whales to be potentially affected by the 
proposed survey activities due to its location far offshore of the 
bowhead fall migration pathway.
    Some monodontids may be exposed to sounds produced by the airgun 
arrays during the proposed survey, and the numbers potentially affected 
are small relative to the population sizes (see Table 6 of the IHA 
application). The best estimate of the number of belugas (224 animals) 
that might be exposed to >= 160 dB and/or >= 120 dB represents less 
than one percent (0.57 percent) of their regional population.
    The many reported cases of apparent tolerance by cetaceans of 
seismic exploration, vessel traffic, and some other human activities 
show that co-existence is possible. Monitoring and mitigation measures 
such as controlled vessel speed, dedicated PSOs, non-pursuit, shut-
downs or power-downs when marine mammals are seen within defined ranges 
will further reduce short-term reactions and minimize any effects on 
hearing sensitivity. In all cases, the effects are expected to be 
short-term, with no lasting biological consequence.
    Several pinniped species may be encountered in the study area, but 
the ringed seal is by far the most abundant marine mammal species in 
the survey area. The best (average) estimates of the numbers of 
individual seals exposed to airgun sounds at received levels >= 160 dB 
re 1 [mu]Pa (rms) and/or >= 120 dB re 1 [mu]Pa (rms) for icebreaking 
during the marine survey are as follows: Ringed seals (1,328 animals; 
7.4 percent of the regional population), bearded seals (67 animals; 
0.02 percent of the regional population), and spotted seals (0 animals, 
0 percent of the regional population), representing less than a few 
percent of the Bering-Chukchi-Beaufort populations for each species. It 
is probable that only a small percentage of the pinnipeds exposed to 
sound level >= 160 dB (rms) or 120 dB (rms) would actually be 
disturbed. The short-term exposures of pinnipeds to airgun sounds are 
not expected to result in any long-term negative consequences for the 
individuals or their populations.

Potential Effects on Habitat

    The proposed USGS seismic survey will not result in any permanent 
impact on habitats used by marine mammals, including the food sources 
they use. The proposed activities will be of short duration in any 
particular area at any given time; thus any effects would be localized 
and short-term. However, the main impact issue associated with the 
proposed activity will be temporarily elevated noise levels and the 
associated direct effects on marine mammals, as described above.
    Icebreaking could alter ice conditions in the immediate area around 
the vessels. However, ice conditions at this time of year are typically 
highly variable and relatively unstable in most locations the survey 
will take place. Although there is the potential for the destruction of 
ringed seal lairs or polar bear dens due to icebreaking, these animals 
will not be using lairs or dens at the time of the planned survey.
    One of the reasons for the adoption of airguns as the standard 
energy source for marine seismic surveys was that, unlike explosives, 
they do not result in any appreciable fish kill. However, the existing 
body of information relating to the impacts of seismic on marine fish 
and invertebrate species, the primary food sources of pinnipeds and 
belugas, is very limited.
    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 (Hubbs and Rechnitzer, 1952; Wardle et al., 2001). 
Generally, the higher the received pressure and less time required for 
the pressure to rise and decay, the greater the chance of acute 
pathological effects. Considering the peak pressure and rise/decay time 
characteristics of seismic airgun arrays used today, the pathological 
zone for fish and invertebrates would be expected to be within a few 
meters of the seismic source (Buchanan et al., 2004). For the proposed 
survey, any injurious effects on fish would be limited to very short 
distances from the sound source and well away from the nearshore waters 
where most subsistence fishing activities occur.
    The only designated Essential Fish Habitat (EFH) species that may 
occur in the area of the project during the seismic survey are salmon 
(adult), and their occurrence in waters north of the Alaska coast is 
limited. Adult fish near seismic operations are likely to avoid the 
immediate vicinity of the source, thereby avoiding injury (see Appendix 
E of the IHA application). No EFH species will be present as very early 
life stages when they would be unable to avoid seismic exposure that 
could otherwise result in minimal mortality.
    Studies have been conducted on the effects of seismic activities on 
fish larvae and a few other invertebrate animals. Generally, seismic 
was found to only have potential harmful effects to larvae and 
invertebrates that are in direct proximity (a few meters) of an active 
airgun array (see Appendix E and F of the IHA application). The 
proposed Arctic Sea seismic program for 2010 is predicted to have 
negligible to low physical effects on the various life stages of life 
and invertebrates. Therefore, physical effects of the proposed program 
on fish and invertebrates would not be significant.
    The Healy is designed for continuous passage at 5.6 km (3 knots) 
through ice 1.4 m (4.6 ft) thick. During this project the Healy will 
typically encounter first- or second-year ice while avoiding thick ice 
floes, particularly large intact multi-year ice, whenever possible. In 
addition, the icebreaker will follow leads when possible while 
following the survey route. As the icebreaker passes through the ice, 
the ship causes the ice to part and travel alongside the hull. This ice 
typically returns to fill the wake as the ship passes. The effects are 
transitory, i.e., hours at most, and localized, i.e., constrained to a 
relatively narrow swath perhaps 10 m (32.8 ft) to each side of the 
vessel.
    The Healy's maximum beam is 25 m (82 ft). Applying the maximum 
estimated amount of icebreaking, i.e., 3,372 km (2,095.3 mi), to the 
corridor opened by the ship, USGS anticipates that a maximum of 
approximately 152 km\2\ (58.7 mi\2\) of ice may be disturbed. This 
encompasses an insignificant amount (less than 0.005 percent) of the 
total Arctic ice extent in August and September of 2008 and 2009 which 
ranged from 3.24 million to 4.1 million km\2\ (1,235,527 to 1,583,019 
mi\2\).

[[Page 39357]]

Potential Effects on Marine Mammal Habitat

    The proposed airgun operations will not result in any permanent 
impact on habitats used by marine mammals, or to the food sources they 
use. The main impact issue associated with the proposed activities will 
be temporarily elevated noise levels and the associated direct effects 
on marine mammals, as well as the potential effects of icebreaking. The 
potential effects of icebreaking include locally altered ice conditions 
which may temporarily alter the haul-out pattern of seals in the 
immediate vicinity of the vessel. The destruction of ringed seal lairs 
or polar bear dens is not expected to be a concern at this time of 
year.
    During the seismic survey only a small fraction of the available 
habitat would be ensonified at any given time. Disturbance to fish 
species would be short-term and fish would return to their pre-
disturbance behavior once the seismic activity ceases. Thus, the 
proposed survey would have little, if any, impact on the abilities of 
marine mammals to feed in the area where seismic work is planned.
    Some mysticetes, including bowhead whales, feed on concentrations 
of zooplankton. Some feeding bowhead whales may occur in the Alaskan 
Beaufort Sea in July and August, and other feed intermittently during 
their westward migration in September and October (Richardson and 
Thomson, 2002; Lowry et al., 2004; Lyons et al., 2009; Christi et al., 
2009). A reaction by zooplankton to a seismic impulse would only be 
relevant to whales if it caused concentrations of zooplankton to 
scatter. Pressure changes of sufficient magnitude to cause that type of 
reaction would probably occur only very close to the source. Impacts on 
zooplankton behavior are predicted to be negligible, and that would 
translate into negligible impacts on feeding mysticetes.
    Thus, the proposed activity is not expected to have any habitat-
related effects that could cause significant or long-term consequences 
for individual marine mammals or their populations, since operations at 
any specific location will be limited in duration.
    Icebreaking will create temporary leads in the ice and could 
possibly destroy unoccupied seal lairs. Seal pups are born in the 
spring, therefore, pupping and nursing will have concluded and the 
lairs will be vacated at the time of the proposed survey. Breaking ice 
may damage seal breathing holes and will also reduce the haul-out area 
in the immediate vicinity of the ship's track.
    Icebreaking along a maximum of 3,372 km (2,095.3 mi) of trackline 
will alter local ice conditions in the immediate vicinity of the 
vessel. This has the potential to temporarily lead to a reduction of 
suitable seal haul-out habitat. However the dynamic sea-ice environment 
requires that seals be able to adapt to changes in sea, ice, and snow 
conditions, and they therefore create new breathing holes and lairs 
throughout winter and spring (Hammill and Smith, 1989). In addition, 
seals often use open leads and cracks in the ice to surface and breathe 
(Smith and Stirling, 1975). Disturbance to the ice will occur in a very 
small area (less than 0.005 percent) relative to the Arctic icepack and 
no significant impact on marine mammals is anticipated by icebreaking 
during the proposed project.

Proposed Mitigation

    In order to issue an Incidental Take Authorization (ITA) for small 
numbers of marine mammals under Section 101(a)(5)(D) of the MMPA, NMFS 
must set forth the permissible methods of taking pursuant to such 
activity and other means of effecting the least practicable adverse 
impact on such species or stock and its habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of such species or stock for 
taking for certain subsistence uses. For the proposed seismic survey in 
the Arctic Ocean, USGS will deploy an airgun array of three G-airguns. 
The source will be relatively small in size and source level, relative 
to airgun arrays typically used for industry seismic surveys. Important 
mitigation factors built into the design of the survey include the 
following:
     In deep offshore waters (where the survey will occur), 
sound from the airguns is expected to attenuate relatively rapidly as 
compared with attenuation in shallower waters;
     The airguns comprising the array will be clustered with 
only limited horizontal separation (see Appendix B of the IHA 
application), so the arrays will be less directional than is typically 
the case with larger airgun arrays. This will result in less downward 
directivity than is often present during seismic surveys, and more 
horizontal propagation of sound; and
     Airgun operations will be limited to offshore waters, far 
from areas where there is subsistence hunting or fishing, and in waters 
where marine mammal densities are generally low.
    In addition to the mitigation measure that are built into the 
general project design, several specific mitigation measures will be 
implemented to avoid or minimize effects on marine mammals encountered 
along the tracklines. These include ramping-up the airguns at the 
beginning of operations, and power-downs or shut-downs when marine 
mammals are detected within specified distances from the source. The 
GSC has written a Categorical Declaration (see Appendix C of the IHA 
application) stating that: ``While in U.S. waters (i.e., the U.S. 200 
mile EEZ), the GSC operators will comply with any and all environmental 
mitigation measures required by the U.S. National Marine Fisheries 
Service (NMFS) and/or the U.S. Fish and Wildlife Service (USFWS).''
    Received sound fields were measured for the airgun configuration, 
in relation to distance and direction from the airgun(s). The proposed 
radii around the airgun(s) where received levels would be 180 and 190 
dB (rms) are shown in Table 2 of the IHA application. The 180 and 190 
dB (rms) levels are used to initiate a power-down or, if necessary, 
shut-down criteria applicable to cetaceans and pinnipeds, respectively, 
as specified by NMFS (2000).
    Vessel-based PSOs will watch for marine mammals near the airgun(s) 
when they are in use. Mitigation and monitoring measures proposed to be 
implemented for the seismic survey have been developed and refined in 
cooperation with NMFS during previous seismic studies in the Arctic and 
described in associated EAs, IHA applications, and IHAs. The mitigation 
and monitoring measures described herein represent a combination of the 
procedures required by past IHAs for Arctic projects.
    Some cetacean species (such as bowhead whales) may be feeding or 
migrating in the Beaufort Sea during August and September. However, 
most of the proposed geophysical activities will occur north of the 
main migration corridor and the number of individual animals expected 
to closely approach the vicinity of the proposed activity will be small 
in relation to regional population sizes. With the proposed monitoring, 
ramp-up, power-down, and shut-down provisions (see below), any effects 
on individuals are expected to be limited to behavioral disturbance. 
The following subsections provide more detailed information about the 
mitigation measures that are integral part of the planned activity.

Proposed Exclusion Zones (EZ)

    Mosher et al. (2009) collected received sound level data for the 
airgun configuration that will be used in the proposed survey in 
similar water

[[Page 39358]]

depths, i.e., greater than 2,000 m (6,561.7 ft). The empirical data 
were plotted in relation to distance and direction from the three 
airguns by Roth and Schmidt (2010; see Figure B-3). Based on model fit 
to the measured received levels and source modeling estimates from 
Gundalf, the 180 and 190 dB (rms) EZ are estimated to be 216 m (708.7 
ft) and 68 m (223.1 ft), respectively. As a conservation measure for 
the proposed EZ, the sound-level EZ indicated by the empirical data 
have been increased to 500 m (1,640.4 ft) for the 180 dB isopleths and 
to 100 m (328 ft) for the 190 dB isopleths (see Table 2 of the IHA 
application). The 180 and 190 dB levels are shut-down criteria 
applicable to cetaceans and pinnipeds, respectively, as specified by 
NMFS (2000); these levels were used to establish the EZs. If the PSO 
detects marine mammal(s) within or about to enter the appropriate EZ, 
the airguns will be powered-down (or shut-down if necessary) 
immediately (see below).
    Detailed recommendations for new science-based noise exposure 
criteria were published in early 2008 (Southall et al., 2007). USGS 
will be prepared to revise its procedures for estimating numbers of 
mammals ``taken,'' EZs, etc., as may be required by any new guidelines 
that result. As yet, NMFS has not specified a new procedure for 
determining EZs. Such procedures, if applicable would be implemented 
through a modification to the IHA if issued.
    In addition to monitoring, mitigation measures that will be adopted 
during the proposed Arctic Ocean survey include:
    (1) Speed or course alteration, provided that doing so will not 
comprise operational safety requirements;
    (2) Power-down procedures;
    (3) Shut-down procedures; and
    (4) Ramp-up procedures.
    No start-up of airgun operations would be permitted unless the full 
180 dB (rms) EZ is visible for at least 30 min during day or night. 
Other proposed provisions associated with operations at night or in 
periods of poor visibility include the following:
     During foggy conditions or darkness (which may be 
encountered starting in late August), the full 180 dB (rms) EZ may not 
be visible. In that case, the airguns could not start-up after a full 
shut-down until the entire 180 dB (rms) radius was visible.
     During any nighttime operations, if the entire 180 dB 
(rms) EZ is visible using vessel lights, then start-up of the airgun 
array may occur following a 30 min period of observation without 
sighting marine mammals in the EZ.
     If one or more airguns have been operational before 
nightfall, they can remain operational throughout the night, even 
though the entire EZ may not be visible.
    Speed or Course Alteration--If a marine mammal (in water) is 
detected outside the EZ and, based on its position and relative motion, 
is likely to enter the EZ, the vessel's speed and/or direct course may, 
when practical and safe, be changed in a manner that also minimizes the 
effect on the planned science objectives. The marine mammal activities 
and movements relative to the seismic vessel will be closely monitored 
to ensure that the marine mammal does not approach within the EZ. If 
the mammal appears likely to enter the EZ, further mitigative actions 
will be taken, i.e., either further course alterations or power-down or 
shut-down of the airgun(s).
    Power-down Procedures--A power-down involves reducing the number of 
airguns in use such that the radius of the 180 dB or 190 dB (rms) EZ 
are decreased to the extent that marine mammals are no longer in or 
about to enter the EZ. A power-down of the airgun array can also occur 
when the vessel is moving from one seismic line to another. During a 
power-down for mitigation, one airgun (or some other number of airguns 
less than the full airgun array) will be operated. The continued 
operation of one airgun is intended to alert (1) marine mammals to the 
presence of the seismic vessel in the area, and (2) 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 a marine mammal is detected outside the EZ but is likely to 
enter the EZ, and if the vessel's speed and/or course cannot be changed 
to avoid having the marine mammal enter the EZ, the airguns (as an 
alternative to a complete shut-down) will be powered-down to a single 
airgun before the animal is within the EZ. Likewise, if a mammal is 
already within the EZ when first detected, the airguns will be powered-
down immediately if this is a reasonable alternative to a complete 
shut-down. During a power-down of the airgun array, the number of 
airguns will be reduced to a single 150 in\3\ G-airgun will be 
operated. The 180 dB (rms) EZ for the power-down sound source has been 
estimated to be 62 m (203 ft), the proposed distance for use by PSOs is 
75 m (246 ft). If a marine mammal is detected within or near the 
smaller EZ around that single 150 in\3\ airgun (see Table 2 of USGS's 
application and Table 2 above), all airguns will be shut-down (see next 
subsection).
    Following a power-down, operation of the full airgun array will not 
resume until the marine mammal is outside the EZ for the full array. 
The animal will be considered to have cleared the EZ if it:
    (1) Is visually observed to have left the EZ, or
    (2) Has not been seen within the EZ for 15 minutes in the case for 
species with shorter dive durations (e.g., small odontocetes and 
pinnipeds); or
    (3) Has not been seen within the EZ for 30 minutes in the case for 
species with longer dive durations (e.g., mysticetes and large 
odontocetes, including killer whales).
    During airgun operations following a power-down (or shut-down) 
whose duration has exceeded the limits specified above and subsequent 
animal departures, the airgun array will be ramped-up gradually. Ramp-
up procedures are described below.
    Shut-down Procedures--The operating airgun(s) will be shut-down if 
a marine mammal is detected within or approaching the EZ for a single 
airgun source (i.e., a power-down is not practical or adequate to 
reduce exposure to less than 190 or 180 dB (rms), as appropriate). 
Shut-downs will be implemented (1) if an animal approaches or enters 
the EZ of the single airgun after a power-down has been initiated, or 
(2) if an animal is initially seen within the EZ of a single airgun 
when more than one airgun (typically the full array) is operating. 
Airgun activity will not resume until the marine mammal has cleared the 
EZ, or until the PSVO is confident that the animal has left the 
vicinity of the vessel (or the PSVO not observing the animal(s) within 
the EZ for 15 or 30 min depending upon the species). Criteria for 
judging that the animal has cleared the EZ will be as described in the 
preceding subsection. Ramp-up procedures will be followed during 
resumption of full seismic operations after a shut-down of the airgun 
array.
    Ramp-up Procedures--A ramp-up procedure will be followed when the 
airgun array begins operating after a specified period without airgun 
operations or when a power-down (or reduced airgun operations) has 
exceeded that specified duration period. The specified period depends 
on the speed of the source vessel, the size of the airgun array that is 
being used, and the size of the EZ, but is often about 10 min. NMFS 
normally requires that, once ramp-up commences, the rate of ramp-up be 
no more than 6 dB per 5 min period. Ramp-up will begin with a

[[Page 39359]]

single airgun (the smallest airgun in the array). Airguns will be added 
in a sequence such that the source level of the array will increase in 
steps not exceeding 6 dB per 5 min period over a total duration of 
approximately 10 minutes. During ramp-up, the PSVOs will monitor the 
EZ, and if marine mammals are sighted, a power-down or shut-down will 
be implemented as though the full array were operational.
    If the complete 180 dB (rms) EZ has not been visible for at least 
30 min prior to the start of operations in either daylight or 
nighttime, ramp-up will not commence unless at least one airgun (150 
in\3\ or similar) has been operating during the interruption of seismic 
survey operations. Given these provisions, it is likely that the three 
G-airgun array will not be ramped-up from a complete shut-down at night 
or in thick fog, because the outer part of the EZ for that array will 
not be visible during those conditions. If the entire EZ is visible 
using vessel lights, then start-up of the airguns from a complete shut-
down may occur at night. 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 if they choose. Given the responsiveness of bowhead and 
beluga whales to airgun sounds, it can be assumed that those species in 
particular will move away during a ramp-up. Ramp-up of the airguns will 
not be initiated during the day or at night if a marine mammal is 
sighted within or near the applicable EZ during the previous 15 or 30 
min, as applicable.
    Helicopter Flights--The use of a helicopter to conduct ice 
reconnaissance flights and vessel-to-vessel personnel transfers is 
likely to occur during survey activities in U.S. waters. However, 
collection of spot bathymetry data or on-ice landings, both of which 
required low altitude flight patterns, will not occur in U.S. waters.

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) require 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.
    USGS proposes to sponsor marine mammal monitoring during the 
proposed project, in order to implement the proposed mitigation 
measures that require real-time monitoring, to satisfy the anticipated 
monitoring requirements of the IHA proposed by NMFS, and to meet any 
monitoring requirements agreed to as part of the Plan of Cooperation. 
USGS's proposed Monitoring Plan is described below as well as in their 
IHA application. USGS understands that this Monitoring Plan will be 
subject to review by NMFS and others, and that refinements may be 
required as part of the MMPA consultation process.
    The monitoring work described here has been planned as a self-
contained project independent of any other related monitoring projects 
that may be occurring simultaneously in the same regions. USGS is 
prepared to discuss coordination of its monitoring program with any 
related work that might be done by other groups insofar as this is 
practical and desirable.

Vessel-Based Visual Monitoring

    Vessel-based Protected Species Observers (PSOs) will monitor for 
marine mammals near the seismic source vessel during all daytime airgun 
operations and during any nighttime start-ups of the airguns. The 
survey area within U.S. waters is located within high latitudes 
(approximately 72[deg] to 74[deg] North) and the project will take 
place during the summer when little darkness will be encountered (see 
Table 9 of the IHA application). Some periods of darkness will be 
encountered towards the end of the survey when there will be several 
hours between sunset and sunrise.
    The PSO's observations will provide the real-time data needed to 
implement the key mitigation measures. Airgun operations will be 
powered-down or (if necessary) shut-down when marine mammals are 
observed within, or about to enter, designated EZ where there is a 
possibility of effects on hearing or other physical effects. Vessel-
based PSOs will also watch for marine mammals near the seismic vessel 
for at least 30 min prior to the planned start of airgun operations 
after an extended shut-down of the airgun. When feasible, observations 
will also be made during daytime periods without seismic operations 
(e.g., during transits).

 Table 7--The Daylight Times and Periods Within the Proposed Project Area From Beginning (August 7, 2010) To End
 (September 3, 2010) of the Planned Survey Activities Within Latitudes of the Planned Survey Within U.S. Waters.
                                     Time is in Alaska Daylight Time (AKDT).
----------------------------------------------------------------------------------------------------------------
                                                           72[deg] North                   74[deg] North
----------------------------------------------------------------------------------------------------------------
                                                     August 7       September 3      August 7       September 3
----------------------------------------------------------------------------------------------------------------
Sunrise.........................................           09:29           12:14  ..............           12:00
Sunset..........................................           06:42           03:45  ..............           03:59
Period of daylight (hours)......................           21:13           15:31           24:00           15:59
----------------------------------------------------------------------------------------------------------------

     During daylight, vessel-based PSOs will watch for marine 
mammals near the seismic vessel during all periods of airgun activity 
and for a minimum of 30 min prior to the planned start of airgun 
operations after an extended shut-down.
     Although there will be only a brief period during the 
survey when darkness will be encountered in U.S. waters, USGS proposes 
to conduct nighttime as well as daytime operations. PSOs dedicated to 
protected species observations are proposed not to be on duty during 
ongoing seismic operations at night, given the very limited 
effectiveness of visual observation at night. At night, bridge 
personnel will watch for marine mammals (insofar as practical at night) 
and will call for the airguns to be shut-down if marine mammals are 
observed in or about to enter the EZ.
    PSOs will be stationed aboard both the seismic source vessel (St. 
Laurent) and Healy during the proposed survey. The vessels will 
typically work together in tandem while making way through heavy ice 
with the Healy in the lead breaking ice and collecting multi-beam data. 
The St. Laurent will follow

[[Page 39360]]

collecting seismic reflection and refraction data. In light ice 
conditions, the vessels will separate to maximize data collection. 
``Real-time'' communication between the two vessels regarding marine 
mammal detections will be available through VHF radio.
    During operations in U.S. EEZ waters, a complement of five PSOs 
will work on the source vessel, the St. Laurent, and two will be 
stationed on the Healy. Three trained PSOs will board the St. Laurent 
in Kagluktuk, Nunavut, Canada. Three experienced PSOs and one Alaska 
Native community observer will be aboard the Healy at the outset of the 
project. Before survey operations begin in U.S. waters, two of the PSOs 
on the Healy will transfer to the St. Laurent to provide additional 
observers during airgun operations. When not surveying in U.S. waters, 
the distribution of PSOs will return to three on the St. Laurent and 
four on the Healy.
    PSOs on the St. Laurent will monitor for marine mammals during all 
daylight airgun operations. Airgun operations will be shut-down when 
marine mammals are observed within, or about to enter, designated EZ 
(see below) where there may be a possibility of significant effects on 
hearing or other physical effects. PSOs on both the source vessel and 
the Healy will also watch for marine mammals within or near the EZ for 
at least 30 min prior to the planned start of airgun operations after 
an extended shut-down of the airgun array. When feasible, observations 
will also be made during periods without seismic operations (e.g., 
during transits). Environmental conditions will be recorded every half 
hour during PSO watch.
    The PSOs aboard the Healy will also watch for marine mammals during 
daylight seismic activities conducted in both U.S. and international 
waters. They will maximize their time on watch but will not watch 
continuously, as will those on the St. Laurent, because they will not 
have mitigation duties and there will be only two PSOs aboard the 
Healy. The Healy PSOs will report sightings to the PSOs on the St. 
Laurent to alert them of possible needs for mitigation.
    In U.S. waters, at least one observer, and when practical two 
observers, will monitor for marine mammals from the St. Laurent during 
ongoing daytime operations and nighttime start-ups (when darkness is 
encountered). Use of two simultaneous observers will increase the 
proportion of the animals present near the source vessel that are 
detected. PSOs will normally be on duty in shifts of no longer than 
four hours duration although more than one hour shift may be worked per 
day with a maximum of 12 hour of daily watch time. During seismic 
operations in international waters, PSOs aboard the St. Laurent will 
conduct eight hour watches. This schedule accommodates 24 hour/day 
monitoring by three PSOs which will be necessary during most of the 
survey when daylight will be continuous. Healy PSOs will limit watches 
to four hours in U.S. waters.
    The St. Laurent crew will be instructed to assist in detecting 
marine mammals and implementing required mitigation (if practical). The 
crew will be given instruction on mitigation requirements and 
procedures for implementation of mitigation prior to the start of the 
seismic survey. Members of the Healy crew will be trained to monitor 
for marine mammals and asked to contact the Healy observers for 
sightings that occur while the PSOs are off-watch.
    The St. Laurent and Healy are suitable platforms for observations 
for marine mammals. When stationed on the flying bridge, eye level will 
be approximately 15.4 m (51 ft) above sea level on the St. Laurent and 
approximately 24 m (78.7 ft) above sea level on the Healy. On both 
vessels the PSO will have an unobstructed view around the entire vessel 
from the flying bridge. If surveying from the bridge of the St. Laurent 
or the Healy the PSO's eye level will be approximately 12.1 m (40 ft) 
above sea level or 21.2 m (69 ft) above sea level, respectively. The 
PSO(s) will scan the area around the vessel systematically with laser 
range finding binoculars and with the unaided eye.
    The survey will be conducted at high latitudes and continuous 
daylight will persist through much of the proposed survey area through 
the month of August. Day length will decrease to approximately 18 hours 
in the northern portion of the survey area by about early September. 
Laser range-finding binoculars (Leica LRF 1200 laser rangefinder or 
equivalent) will be available to assist with distance estimation; this 
equipment is useful in training observers to estimate distances 
visually, but is generally not useful in measuring distances to animals 
directly.
    When marine mammals are detected within or about to enter the 
designated EZ, the airgun(s) will be powered-down or shut-down 
immediately. The distinction between power-downs and shut-downs is 
described in the IHA application. Channels of communication between the 
PSOs and the airgun technicians will be established to assure prompt 
implementation of shut-downs when necessary as has been done in other 
recent seismic survey operations in the Arctic (e.g., Haley, 2006). 
During power-downs and shut-downs, PSOs will continue to maintain watch 
to determine when the animal(s) are outside the EZ. Airgun operations 
will not resume until the animal is outside the EZ. The animal will be 
considered to have cleared the EZ if it is visually observed to have 
left the EZ. Alternatively, in U.S. waters the EZ will be considered 
clear if the animal has not been seen within the EZ for 15 min for 
small odontocetes and pinnipeds or 30 min for mysticetes. Within 
international waters the PSOs will apply a 30 min period for all 
species.

PSO Data and Documentation

    PSOs will record data to estimate the numbers of marine mammals 
exposed to various received sound levels and to document apparent 
disturbance reactions or lack thereof. Data will be used to estimate 
numbers of animals potentially `taken' by harassment (as defined in the 
MMPA). They will also provide information needed to order a power-down 
or shut-down of the seismic source when a marine mammal is within or 
near the EZ.
    When a sighting is made, the following information about the 
sighting will be recorded:
    (1) Species, group size, and 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 seismic source 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) above will also be recorded at the start 
and end of each observation watch, and during a watch whenever there is 
a change in one or more of the variables.
    All observations, as well as information regarding seismic source 
power-downs and shut-downs, will be recorded in a standardized format. 
Data will be entered into a custom database using a notebook computer. 
The accuracy of 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.

[[Page 39361]]

    Results for 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 per 
terms of MMPA authorizations or regulations.
    (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.
    A report on USGS activities and on the relevant monitoring and 
mitigation results will be submitted to NMFS 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 be submitted to NMFS, providing full documentation of 
methods, results, and interpretation pertaining to all acoustic 
characterization work and vessel-based monitoring. The 90-day report 
will summarize the dates and locations of seismic operations, and all 
marine mammal sightings (dates, times, locations, activities, 
associated seismic survey activities). The number and circumstances of 
ramp-ups, power-downs, shut-downs, and other mitigation measures will 
be reported. Sample size permitting, the report will also include 
estimates of the amount and nature of potential ``take'' of marine 
mammals by harassment or in other ways.
    All injured or dead marine mammals (regardless of cause) will be 
reported to NMFS as soon as practicable. Report should include species 
or description of animal, condition of animal, location, time first 
found, observed behaviors (if alive) and photo or video, if available.

Encouraging and Coordinating Research

    USGS will coordinate the planned marine mammal monitoring program 
associated with the seismic survey in the Arctic Ocean with other 
parties that may have interest in this area and/or be conducting marine 
mammal studies in the same region during operations. No other marine 
mammal studies are expected to occur in the main (northern) parts of 
the study area at the proposed time. However, other industry-funded 
seismic surveys may be occurring in the northeast Chukchi and/or 
western Beaufort Sea closer to shore, and those projects are likely to 
involve marine mammal monitoring. USGS has coordinated, and will 
continue to coordinate, with other applicable Federal, State and 
Borough agencies, and will comply with their requirements.

Negligible Impact and Small Numbers of Marine Mammals Analysis and 
Determination

    The Secretary, in accordance with paragraph 101(a)(5)(D) of the 
MMPA, shall authorize the take of small numbers of marine mammals 
incidental to specified activities other than commercial fishing within 
a specific geographic region if, among other things, he determines that 
the authorized incidental take will have a ``negligible impact'' on 
species or stocks affected by the authorization. NMFS implementing 
regulations codified at 50 CFR 216.103 states that a ``negligible 
impact is 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.''
    Based on the analysis contained herein, of the likely effects of 
the specified activity on marine mammals and their habitat within the 
specific area of study for the Arctic Ocean marine geophysical survey, 
and taking into consideration the implementation of the mitigation and 
monitoring measures NMFS, on behalf of the Secretary, preliminary finds 
that USGS's proposed activities would result in the incidental take of 
small numbers of marine mammals, by Level B harassment only, and that 
the total taking from the proposed seismic survey would have a 
negligible impact on the affected species or stocks of marine mammals. 
As a basis for its small numbers determination, NMFS evaluated the 
number of individuals taken by Level B harassment relative to the size 
of the stock or population.
    While the number of marine mammals potentially incidentally 
harassed will depend on the distribution and abundance of marine 
mammals in the vicinity of the survey activity, the number of potential 
Level B incidental harassment takings (see Table 6 above) is estimated 
to be small, less than a few percent of any of the estimated population 
sizes based on the data disclosed in Table 4 and 6 of this notice, and 
has been mitigated to the lowest level practicable through the 
incorporation of the monitoring and mitigation measures mentioned 
previously in this document. Tables 4 and 6 in this notice disclose the 
habitat regional abundance, conservation status, density, and the 
number of individuals exposed to sound levels greater than or equal to 
120 dB (rms) (for icebreaking) or 160 dB (rms) (for seismic airgun 
operations). Also, there are no known important reproduction or feeding 
areas in the proposed action area.
    For reasons stated previously in this document, the specified 
activities associated with the proposed survey are not likely to cause 
TTS, PTS or other non-auditory injury, serious injury, or death to 
affected marine mammals because:
    (1) The likelihood that, given sufficient notice through relatively 
slow ship speed, marine mammals are expected to move away from a noise 
source that is annoying prior to its becoming potentially injurious;
    (2) The fact that cetaceans and pinnipeds would have to be closer 
than 500 m (1,640.4 ft) and 30 m (98.4 ft), in deep water when the full 
array is in use at tow depth from the vessel to be exposed to levels of 
sound (180 dB and 190 dB, respectively) believed to have even a minimal 
chance of causing PTS;
    (3) The fact that marine mammals would have to be closer than 2,500 
m (8,202.1 ft) in deep water when the full array is in use at tow depth 
from the vessel to be exposed to levels of sound (160 dB) believed to 
have even a minimal chance at causing TTS; and
    (4) The likelihood that marine mammal detection ability by trained 
observers is high at that short distance from the vessel.
    As a result, no take by injury, serious injury, or death is 
anticipated or authorized, and the potential for temporary or permanent 
hearing impairment is very low and will be avoided through the 
incorporation of the proposed monitoring and mitigation measures.
    In making a negligible impact determination NMFS evaluated factors 
such as: no anticipated injury, serious injury or mortality; the 
number, nature, intensity and duration of harassment (all relatively 
limited); the low probability that take will likely result in effects 
to annual rates of recruitment of survival; the context in which it 
occurs (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); the 
status of stock or species of marine mammal (i.e., depleted, not 
depleted, decreasing, increasing, stable, impact relative to the size 
of the population); impacts on habitat affecting rates of

[[Page 39362]]

recruitment/survival; and the effectiveness of monitoring and 
mitigation measures

Impact on Availability of Affected Species for Taking for Subsistence 
Uses

    There is subsistence hunting for marine mammals in the waters off 
of the coast of Alaska, in the Arctic Ocean, that implicates MMPA 
Section 101(a)(5)(D). Subsistence hunting and fishing continue to be 
prominent in the household economies and social welfare of some Alaska 
residents, particularly among those living in small, rural villages 
(Wolfe and Walker, 1987; Braund and Kruse, 2009). Subsistence remains 
the basis for Alaska Native culture and community. In rural Alaska, 
subsistence activities are often central to many aspects of human 
existence, including patterns of family life, artistic expression, and 
community religious and celebratory activities.

Subsistence Hunting

    Marine mammals are legally hunted in Alaskan waters by coastal 
Alaska Natives; species hunted include bowhead and beluga whales; 
ringed, spotted, and bearded seals; walruses, and polar bears. The 
importance of each of the various species varies among the communities 
based largely on availability. Bowhead whales, belugas, and walruses 
are the marine mammal species primarily harvested during the time of 
the proposed seismic survey. Subsistence remains the basis for Alaska 
Native culture and community, and subsistence activities are often 
central to many aspects of human existence, including patterns of 
family life, artistic expression, and community religious and 
celebratory activities.
    Bowhead whale hunting is a key activity in the subsistence 
economies of Barrow and other Native communities along the Beaufort Sea 
coast. The whale harvests have a great influence on social relations by 
strengthening the sense of Inupiat culture and heritage in addition to 
reinforcing family and community ties.
    An overall quota system for the hunting of bowhead whales was 
established by the International Whaling Commission in 1977. The quota 
is now regulated through an agreement between NMFS and the Alaska 
Eskimo Whaling Commission (AEWC) which extends to 2012 (NMFS, 2008b). 
The AEWC allows the number of bowhead whales that each whaling 
community may harvest annually during five-year periods (USDI/BLM, 
2005; NMFS, 2008).
    The community of Barrow hunts bowhead whales in both the spring and 
fall during the whales' seasonal migration along the coast (see Figure 
2 of the IHA application). Often the bulk of the Barrow bowhead harvest 
is taken during the spring hunt. However, with larger quotas in recent 
years, it is common for a substantial fraction of the annual Barrow 
quota to remain available for the fall hunt (see Table 7 of the IHA 
application). The communities of Nuiqsut and Kaktovik participate only 
in the fall bowhead harvest. The fall migration of bowhead whales that 
summer in the eastern Beaufort Sea typically begins in late August or 
September. Fall migration into Alaskan waters is primarily during 
September and October. However, in recent years a small number of 
bowheads have been seen or heard offshore from the Prudhoe Bay region 
during the last week of August (Treacy, 1993; LGL and Greenridge, 1996; 
Greene, 1997; Greene et al., 1999; Blackwell et al., 2004).

 Table 8--Number of Bowhead Whale Landing by Year at Barrow, Cross Island (Nuiqsut), and Kaktovik, 1993 to 2008.
 Barrow Numbers Include the Total Number of Whales Landed for the Year Followed by the Numbers Landed During the
              Fall Hunt in Parentheses. Cross Island (Nuiqsut) and Kaktovik Landings Are in Autumn.
----------------------------------------------------------------------------------------------------------------
              Year                  Point hope      Wainwright        Barrow       Cross island      Kaktovik
----------------------------------------------------------------------------------------------------------------
1993............................               2               5          23 (7)               3               3
1994............................               5               4          16 (1)               0               3
1995............................               1               5         19 (11)               4               4
1996............................               3               3         24 (19)               2               1
1997............................               4               3         30 (21)               3               4
1998............................               3               3         25 (16)               4               3
1999............................               2               5          24 (6)               3               3
2000............................               3               5         18 (13)               4               3
2001............................               4               6          27 (7)               3               4
2002............................               0               1         22 (17)               4               3
2003............................               4               5          16 (6)               4               3
2004............................               3               4         21 (14)               3               3
2005............................               7               4         29 (13)               1               3
2006............................               0               2         22 (19)               4               3
2007............................               3               4          20 (7)               3               3
2008............................               2               2         21 (12)               4               3
----------------------------------------------------------------------------------------------------------------
Sources: USDI/BLM and references therein; Burns et al., 1993; Koski et al., 2005; Suydam et al., 2004, 2005,
  2006, 2007, 2008, and 2009.

    The spring hunt at Barrow occurs after leads open due to the 
deterioration of pack ice; the spring hunt typically occurs from early 
April until the first week of June. The location of the fall 
subsistence hunt depends on ice conditions and (in some years) 
industrial activities that influence the bowheads as they move west 
(Brower, 1996). In the fall, subsistence hunters use aluminum or 
fiberglass boats with outboards. Hunters prefer to take bowheads close 
to shore to avoid a long tow during which the meat can spoil, but 
Braund and Moorehead (1995) report that crews may (rarely) pursue 
whales as far as 80 km (49.7 mi). The fall hunts begin in late August 
or early September in Kaktovik and at Cross Island. At Barrow the fall 
hunt usually begins in mid-September, and mainly occurs in the waters 
east and northeast of Point Barrow in the Chukchi Sea (Suydam et al., 
2008). The whales have usually left the Beaufort Sea by late October 
(Treacey, 2002a,b).
    The scheduling of this seismic survey has been discussed with 
representatives of those concerned with the subsistence bowhead hunt, 
most notably the AEWC, the Barrow Whaling Captains' Association, and 
the North Slope Borough (NSB) Department of Wildlife Management. The 
timing of the proposed seismic survey in early to mid-August will 
affect neither the

[[Page 39363]]

spring nor the fall bowhead hunt. The Healy is planning to change crew 
after the completion of the seismic survey through Barrow via 
helicopter or boat. That crew change is scheduled for approximately 
September 4 to 5, 2010, well before the fall bowhead whaling which 
typically begins late September or early October. All of the proposed 
geophysical activities will occur offshore between 71[deg] and 84[deg] 
North latitude well north of Beaufort Sea whaling activities.
    Beluga whales are available to subsistence hunters at Barrow in the 
spring when pack-ice conditions deteriorate and leads open up. Belugas 
may remain in the area through June and sometimes into July and August 
in ice-free waters. Hunters usually wait until after the spring bowhead 
whale hunt is finished before turning their attention to hunting 
belugas. The average annual harvest of beluga whales taken by Barrow 
for 1962 to 1982 was five (MMS, 1996). The Alaska Beluga Whale 
Committee recorded that 23 beluga whales had been harvested by Barrow 
hunters from 1987 to 2002, ranging from zero in 1987, 1988 and 1995 to 
the high of eight in 1997 (Fuller and George, 1997; Alaska Beluga Whale 
Committee, 2002 in USDI/BLM, 2005). The proposed seismic survey is 
unlikely to overlap with the beluga harvest, and the survey initiates 
well outside the area where impacts to beluga hunting by Barrow 
villagers could occur.
    Ringed seals are hunted mainly from October through June. Hunting 
for these smaller mammals is concentrated during winter because bowhead 
whales, bearded seals, and caribou are available through other seasons. 
In winter, leads and cracks in the ice off points of land and along 
barrier islands are used for hunting ringed seals. The average annual 
ringed seal harvest by the community of Barrow from the 1960s through 
much of the 1980s has been estimated as 394 (see Table 8 of the IHA 
application). More recently Bacon et al. (2009) estimated that 586, 
287, and 413 ringed seals were harvest by villagers at Barrow in 2000, 
2001, and 2003, respectively. Although ringed seals are available year-
round, the seismic survey will not occur during the primary period when 
these seals are typically harvested. Also, the seismic survey will be 
largely in offshore waters where the activities will not influence 
ringed seals in the nearshore areas where they are hunted.
    The spotted seal subsistence hunt peaks in July and August at least 
in 1987 to 1990, but involves few animals. Spotted seals typically 
migrate south by October to overwinter in the Bering Sea, Admiralty 
Bay, less than 60 km (37.3 mi) to the east of Barrow, is a location 
where spotted seals are harvested. Spotted seals are also occasionally 
hunted in the area off Point Barrow and along the barrier islands of 
Elson Lagoon to the east (USDI/BLM, 2005). The average annual spotted 
seal harvest by the community of Barrow from 1987 to 1990 was one 
(Braund et al., 1993; see Table 7 of the IHA application). More 
recently however, Bacon et al. (2009) estimated that 32, 7, and 12 
spotted seals were harvested by villagers at Barrow in 2000, 2001, and 
2003, respectively. Spotted seals become less abundant at Nuiqsut and 
Kaktovik and few if any spotted seal are harvested at these villages. 
The seismic survey will commence at least 115 km (71.5 mi) offshore 
from the preferred nearshore harvest area of these seals.
    Bearded seals, although not favored for their meat, are important 
to subsistence activities in Barrow because of their skins. Six to nine 
bearded seal hides are used by whalers to cover each of the skin-
covered boats traditionally used for spring whaling. Because of their 
valuable hides and large size, bearded seals are specifically sought. 
Bearded seals are harvested during the summer months in the Beaufort 
Sea (USDI/BLM, 2005). The animals inhabit the environment around the 
ice floes in the drifting ice pack, so hunting usually occurs from 
boats in the drift ice. Braund et al. (1993) estimated that 174 bearded 
seals were harvested annually at Barrow from 1987 to 1990 (see Table 8 
of the IHA application). More recently Bacon et al. (2009) estimated 
that 728, 327, and 776 bearded seals were harvested by villagers at 
Barrow in 2000, 2001, and 2003, respectively. Braund et al. (1003) 
mapped the majority of bearded seal harvest sites from 1987 to 1990 as 
being within approximately 24 km (14.9 mi) of Point Barrow, well 
inshore of the proposed survey which is to start approximately 115 km 
(71.5 mi) offshore and terminate greater than 200 km (124.3 mi) 
offshore. The average annual take of bearded seals by the Barrow 
community from 1987 to 1990 was 174 (see Table 8 of the IHA 
application).

   Table 9--Average Annual Take of Marine Mammals Other Than Bowhead Whales Harvest by the Community of Barrow
                               (Compiled by LGL Alaska Research Associates, 2004)
----------------------------------------------------------------------------------------------------------------
                        Beluga whales                            Ringed seals    Bearded seals    Spotted seals
----------------------------------------------------------------------------------------------------------------
5**..........................................................            394*             174*               1*
----------------------------------------------------------------------------------------------------------------
* Average annual harvest for years 1987 to 1990 (Braund et al., 1993).
** Average annual harvest for years 1962 to 1982 (MMS, 1996).

Plan of Cooperation

    The USGS has communicated with community authorities and residents 
of Barrow to foster understanding of the proposed survey. There are 
elements of the proposed survey, intrinsic to the project, that 
significantly limit the potential conflict with subsistence users. 
Operations will be conducted during early August before bowhead whale 
hunting typically occurs off Barrow and approximately 108 km (67.1 mi) 
offshore, farther offshore than traditional subsistence hunting 
grounds. USGS continues to work with the people of Barrow to identify 
and avoid areas of potential conflict.
     The USGS initiated contact with NSB scientists and the 
chair of the AEWC in mid-December, 2010 via an e-mailed description of 
the proposed survey that included components intended to minimize 
potential subsistence conflict.
     Invitations were extended December 31, 2009 to members of 
the NSB, AEWC, and North Slope Communities to attend a teleconference 
arranged for January 11, 2010. The teleconference served as a venue to 
promote understanding of the project and discuss shareholder concerns. 
Participants in the teleconference included Harry Brower, chair of the 
AEWC, and NSB wildlife biologist Dr. Robert Suydam.
     To further promote cooperation between the project 
researchers and the community, Dr. Deborah Hutchinson with USGS 
presented the proposed survey at a meeting of the AEWC in Barrow on 
February 11, 2010. Survey plans were explained to local hunters and 
whaling captains, including NSB Department of Wildlife Management

[[Page 39364]]

biologists, Craig George and Dr. Robert Suydam. Dr. Hutchinson 
consulted with stakeholders about their concerns and discussed the 
aspects of the survey designed to mitigate impacts.
     Dr. Deborah Hutchinson of the USGS e-mailed a summary of 
the topics discussed during the teleconference and the AEWC meeting in 
Barrow to representatives of the NSB, AEWC, and North Slope 
communities. These included:
    [cir] Surveying within U.S. waters is scheduled early 
(approximately August 7 to 12) to avoid conflict with hunters.
    [cir] The EA and IHA application will be distributed as early as 
possible to NSB and AEWC.
    [cir] A community observer will be present aboard the Healy during 
the project.
    [cir] Mitigation of the one crew transfer near Barrow in early 
September will be arranged--probably through Barrow Volunteer Search 
and Rescue.
     Representatives of the USGS attended the Arctic Open-water 
Meeting in Anchorage, March 22 to 24, 2010.
    [cir] Dr. Deborah Hutchinson presented information regarding the 
proposed survey to the general assembly.
    [cir] Dr. Jonathan Childs and Dr. Deborah Hutchinson met with 
stakeholders and agency representatives while at the meeting.
    Subsequent meetings with whaling captains, other community 
representatives, the AEWC, NSB, and any other parties to the plan will 
be held if necessary to coordinate the planned seismic survey operation 
with subsistence hunting activity. The USGS has informed the chairman 
of the Alaska Eskimo Whaling Committee (AEWC), Harry Brower, Jr., of 
its survey plan.
    As noted above and in the IHA application, in the unlikely event 
that subsistence hunting or fishing is occurring within 5 km (3 mi) of 
the project vessel tracklines, or where potential impacts could occur, 
the airgun operations will be suspended until the vessel is greater 
than 5 km away and otherwise not interfering with subsistence 
activities.

Endangered Species Act (ESA)

    On May 21, 2010, USGS initiated informal consultation, under 
Section 7 of the ESA, with the NMFS, Office of Protected Resources, 
Endangered Species Division, on this proposed seismic survey. Based on 
the information provided by USGS, NMFS concurred with their 
determination that the activities conducted during the proposed seismic 
survey are not likely to adversely affect endangered whales in the 
study area. No designated critical habitat occurs within the action 
area for this experiment, therefore, no critical habitat will be 
affected by the proposed bathymetric and seismic surveys and other 
associated activities.

National Environmental Policy Act (NEPA)

    With its complete application, USGS provided NMFS an Environmental 
Assessment (EA) analyzing the direct, indirect and cumulative 
environmental impacts of the proposed specified activities on marine 
mammals including those listed as threatened or endangered under the 
ESA. The EA, prepared by LGL Environmental Research Associated (LGL) on 
behalf of USGS, USCG, and NOAA is titled Draft Environmental Assessment 
of a Marine Geophysical Survey of Portions of the Arctic Ocean, August-
September, 2010 (EA). Prior to making a final decision on the IHA 
application, NMFS will either prepare an independent EA, or, after 
review and evaluation of the USGS 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, adopt the USGS EA 
and make a decision of whether or not to issue a Finding of No 
Significant Impact (FONSI).

Preliminary Determinations

    NMFS has preliminarily determined that the impact of conducting the 
specific marine seismic survey activities described in this notice and 
the IHA request in the specific geographic region within the U.S. EEZ 
within the Arctic Ocean may result, at worst, in a temporary 
modification in behavior (Level B harassment) of small numbers of 
marine mammals. No take by injury (Level A harassment), serious injury, 
or mortality is anticipated, and take by harassment will be at the 
lowest level practicable due to incorporation of the mitigation and 
monitoring measures mentioned previously in this document. Further, 
this activity is expected to result in a negligible impact on the 
affected species or stocks of marine mammals. NMFS has preliminarily 
determined that this proposed activity will not have an unmitigable 
impact on the availability of the affected species or stock of marine 
mammals for subsistence uses. USGS will coordinate with local 
communities on a Plan of Cooperation.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to USGS for conducting a marine seismic survey in the 
Arctic Ocean from August to September, 2010, 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 asks interested persons to submit comments and information 
concerning this proposed project and NMFS' preliminary determination of 
issuing an IHA (see ADDRESSES). Concurrent with the publication of this 
notice in the Federal Register, NMFS is forwarding copies of this 
application to the Marine Mammal Commission and its Committee of 
Scientific Advisors.

    Dated: June 29, 2010.
Helen M. Golde,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2010-16374 Filed 7-7-10; 8:45 am]
BILLING CODE 3510-22-P