Incidental Takes of Marine Mammals During Specified Activities; Shallow Hazard and Site Clearance Surveys in the Chukchi Sea in 2008, 30064-30073 [E8-11537]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 73, Number 101 (Friday, May 23, 2008)]
[Notices]
[Pages 30064-30073]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-11537]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XH65


Incidental Takes of Marine Mammals During Specified Activities; 
Shallow Hazard and Site Clearance Surveys in the Chukchi Sea in 2008

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 ConocoPhillips Alaska, 
Inc. (CPAI) for an Incidental Harassment Authorization (IHA) to take 
small numbers of marine mammals, by harassment, incidental to 
conducting shallow hazard and site clearance surveys using acoustic 
equipment and small airguns in the Chukchi Sea between August and 
October 2008. Under the Marine Mammal Protection Act (MMPA), NMFS is 
requesting comments on its proposed IHA for these activities.

DATES:  Comments and information must be received no later than June 
23, 2008.

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 20910-3225. The mailbox address 
for providing email comments is PR1.0648-XH65@noaa.gov. NMFS is not 
responsible for e-mail comments sent to addresses other than the one 
provided here. Comments sent via e-mail, including all attachments, 
must not exceed a 10-megabyte file size.
    A copy of the application containing a list of the references used 
in this document may be obtained by writing to the address specified 
above, telephoning the contact listed below (see FOR FURTHER 
INFORMATION CONTACT), or visiting the internet at: https://
www.nmfs.noaa.gov/pr/permits/incidental.htm.
    Documents cited in this notice may be viewed, by appointment, 
during regular business hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT:  Shane Guan, Office of Protected 
Resources, NMFS, (301) 713-2289, ext 137.

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 to allow, upon request, the 
incidental, but not intentional, taking of marine mammals by U.S. 
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.
    Authorization shall be granted if NMFS finds that the taking will 
have a negligible impact on the species or stock(s) and will not have 
an unmitigable adverse impact on the availability of the species or 
stock(s) for certain 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 
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].
    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 on any proposed authorizations for the incidental harassment of 
marine mammals. Within 45 days of the close of the comment period, NMFS 
must either issue or deny issuance of the authorization.

Summary of Request

    On April 30, 2008, NMFS received an application from CPAI for the 
taking, by Level B harassment, of several species of marine mammals 
incidental to conducting shallow hazard and site clearance surveys 
using acoustic equipment and small airguns in the Chukchi Sea for up to 
30 - 45 days from approximately August 1, 2008 until October 31, 2008. 
The geographic region of the proposed activities includes two areas 
spaced about 60 km (37 mi) apart and a path for sampling conditions 
along a potential pipeline route. Each area is about 2,000 km2 (772.5 
mi2) with dimensions about 72 km (45 mi) by 62 km (38.5 mi). The two 
areas are about 111 km (69 mi) off the Alaska coast, generally west 
from the village of Wainwright. The marine surveys will be performed 
from a seismic vessel.

Description of the Specified Activity

    CPAI is planning to conduct site clearance and shallow hazard 
surveys of potential exploratory drilling sites in the Chukchi Sea 
during the 2008 open water season. Site clearance and shallow hazard 
surveys would begin in August, after completing mobilization in July. 
CPAI anticipates shooting approximately 5,300 linear km (3,294 mi). The 
operation will be active 24 hours per day and use a single vessel to 
collect the geophysical data.
    Site clearance and shallow hazard surveys will be completed to 
confirm the seafloor has soil and surface characteristics that will 
support the safe set-down of a drill rig, and long term occupation of 
the site by a vessel. Acoustic instrumentation to be used for the 
proposed survey is designed to characterize the seabed topography, 
bathymetry, potential geohazards, and other seafloor features (e.g., 
boulders) using seafloor imaging, water depth measurements, and high-
resolution

[[Page 30065]]

seismic profiling. The proposed site clearance and shallow hazard 
surveys will use the following methods: seafloor imaging, bathymetry, 
and high resolution seismic profiling.

Seafloor Imagery

    Seafloor imagery would use a side-scan sonar, which is a sideward 
looking, two channel, narrow beam instrument that emits a sound pulse 
and listens for its return. The sound energy transmitted is in the 
shape of a cone that sweeps the sea floor resulting in a two 
dimensional image that produces a detailed representation of the 
seafloor and any features or objects on it. The sonar can either be 
hull mounted or towed behind the vessel. One of the following systems 
would be used in the proposed shallow hazard surveys:
    (1) Marine Sonics Technology multi-frequency side-scan sonar: The 
frequency the side-scan sonar emits during operation can be varied from 
150 - 1,200 kilohertz (kHz). It is expected that the frequency for this 
acquisition will be in the 150 kHz range. The pulse length is variable 
from 20 - 300 milliseconds (msec).
    (2) EdgeTech 4200 dual-frequency side scan sonar: The side-scan 
sonar emits sound at frequency of 120 kHz during operation, 
occasionally reaching frequencies up to 410 kHz. The pulse length is up 
to 20 miliseconds (msec), and the source level is approximately 210 dB 
re 1 microPa-m (rms).
    (3) Klein System 3000 dual-frequency digital side scan sonar: This 
side scan sonar would typically be run at the 132 kHz frequency band. 
However, the 445 kHz frequency may be used
    periodically during exploratory testing. The transmission pulse is 
variable from 25 msec to 400 msec. The peak in the 132 kHz source level 
beam reaches 234 dB re 1 microPa-m. The peak in the 445 kHz source 
level beam reaches 242 dB re 1 microPa-m.

Bathymetry

    Echo sounders for measuring water depth are generally mounted to 
the ship hull or on a side-mounted pole. Two different echo sounding 
systems will be used to provide bathymetric data during the proposed 
Chukchi Sea shallow hazard surveys.
    (1) Odom Hydrotrac Digital Echo Sounder: This device is a single 
beam echo sounder, which emits a single pulse of sound directly below 
the ship along the vessel trackline and provides a continuous recording 
of water depth along the survey track. Generally these records require 
heave compensation to rectify the data point. The Hydrotrac sonar 
operates at a frequency of 200 kHz and emits approximately 15 pulses 
per sec. Each pulse phase is between 0.03 and 0.12 msec. The peak 
within the source beam level transmits from 202 to 215 dB re 1 microPa-
m.
    (2) Reson Seabat 8101 Multibeam Echo Sounder: This echo sounder 
consists of a transducer array that emits a swath of sound. The 
seafloor coverage swath of the multibeam sonar is water depth 
dependent, but is usually equal to two to four times the water depth. 
This sonar operates at a frequency of 240 kHz. It emits approximately 
15 pulses per sec with each pulse duration lasting 21 msec to 225 msec 
for a swath that can cover up to 500 m (1,640 ft) in width. The peak in 
the source beam level for the Reson Seabat sonar transmits at 210 dB re 
1 microPa-m. The multibeam system requires additional non-acoustic 
equipment including a motion sensor to measure heave, roll, and pitch, 
a gyrocompass, and a sound velocity probe. A TSSDMS-05 Dynamic Motion 
Sensor, Hemisphere VS-110 Global Positioning System (GPS)/Heading 
System and a Seabird SBE-19 CTD or Odom Digibar Pro will provide these 
data. The resulting multibeam data will provide a three dimensional (3-
D) view of the seafloor in the measured area.

High Resolution Seismic Profiling

    An integral part of the shallow hazards and site clearance surveys 
is high-resolution seismic profiling using three different acoustic 
source systems. Seismic systems operate on the principal that an 
acoustic impulse will reflect part of its energy upon encountering a 
density interface. This will be accomplished through the use of a high-
frequency subbottom profiler, an intermediate-frequency seismic 
profiling system, and a multichannel seismic system. The high-
resolution profiling systems, which use smaller acoustic sources, will 
be utilized as opposed to low-resolution systems or deep exploration 
seismic systems. The planned surveys are geared toward providing detail 
of the surficial and shallow subsurface geology and not toward 
hydrocarbon exploration. The planned high-resolution profiles will 
provide the detailed information that is not resolved in the deep 
seismic profiles. The following equipment will be utilized for the high 
resolution seismic profiling portion of the marine surveys.
    (1) High Resolution Subbottom Profiler
    A subbottom profiler is a high-frequency seismic system that will 
be used to map geologic features in the proposed survey areas. Many of 
the modern subbottom profilers are ``chirp'' systems which are 
frequency or pulse-rate modulated. This allows the energy, amplitude, 
and phase characteristics of the acoustic pulse to be precisely 
controlled. The 500 Hz to 13 kHz frequency in conjunction with the 10-
watt to 4-kilowatt (kW) power output generally achieves 25 to 250 msec, 
or approximately 20 to 200 m (65 to 656 ft) of bottom penetration, 
detailing the near-surface strata and density layers with a resolution 
of 6 to 20 cm (2 to 8 in). The two-way travel time of the acoustic 
signal, from firing to receiving, is recorded and travel time 
measurements are subsequently applied to water column velocity 
information, system delays, and appropriate tow depth corrections to 
calculate water depths and/or depths to subsurface events. The degree 
of ocean bottom penetration is variable depending on properties of the 
bottom and near-surface materials, the output power, and carrier 
frequency. The subbottom profiler is often used to supplement higher 
energy seismic systems or coring data to obtain accurate profiles of 
large areas. One of the following subbottom profiler systems or 
equivalent will be used in the proposed marine surveys:
    (A) Knudsen 320 BR sub-bottom profiling system: The sub-bottom 
profiler will be used in the 3.5 to 12 kHz frequency range. The 
transmission pulse length is programmable sweeps or user defined pings. 
A typical pulse width is 28 - 36 msec. The pulse repetition rate is 4 
pulses/sec - 12 pulses/sec.
    (B) GeoAcoustics/GeoPulse sub-bottom profiling system: The 
subbottom profiler will be used in the 3.5 to 5 kHz frequency range. 
Pulse cycles range from 1 to 32 cycles of the selected frequency. 
During the survey, 3.5 kHz will likely be used, possibly up to 5 kHz, 
depending on the geology of the seafloor.
    (C) GeoAcoustics GeoChirp II subbottom profiling system: The 
subbottom profiler has a frequency range of 0.5 to 13 kHz, which is 
programmable. The transmission pulse length is typically 32 msec 
programmable sweeps or user defined pings. The pulse repetition rate is 
4 pulses/sec (at maximum) for a 32 msec chirp sweep or 10 pulses/sec 
for pinger waveforms.
    All the subbottom profiler has a source level at approximately 214 
dB re 1 microPa-m. The 160, 180, and 190 dB re microPa radii, in the 
beam below the transducer, would be 501 m (1,644 ft), 50 m (164 ft), 
and 16 m (52 ft), respectively, assuming spherical spreading.

[[Page 30066]]

    The corresponding distances for an animal in the horizontal 
direction of these transducers would be much smaller due to the direct 
downward beam pattern of the subbottom profilers. Therefore, the 
horizontal received levels of 180 and 190 dB re 1 microPa (rms) would 
be within much smaller radii than 50 m (164 ft) and 16 m (52 ft) when 
using one of the GeoAcoustics subbottom profilers, which have the 
highest downward source level. In addition, the pulse duration of these 
subbottom profilers is extremely short, in the order of tens to 
hundreds of msec, and the survey is constantly moving. Therefore, for a 
marine mammal to receive prolonged exposure, the animal has to stay in 
a very small zone of ensonification and keep with the vessel's speed, 
which is very unlikely. Moreover, any effects would be less for baleen 
whales due to the frequency range of the profilers. Therefore, the 
potential effects from the sub-bottom profilers to marine mammals would 
be negligible.
    (2) Intermediate Frequency Seismic Profiling System
    One intermediate-frequency seismic system is referred to as a 
``Boomer.'' The boomer transducer is a mechanical means of generating 
enough sound energy to penetrate the subsurface sediments. Signals are 
reflected from the various bedding planes (density/velocity interfaces) 
and received by a single-channel hydrophone streamer. The sound 
reflections are converted into electrical impulses, filtered, and sent 
to a graphic recorder. The Boomer can effectively detail the upper 40 
to 600 m (131 to 1,969 ft) of subbottom, outlining the fine strata and 
density layers that represent foundation formations for seafloor-based 
structures. The depth of seismic penetration obtained with this system 
is determined by the sediment type and the amount of initial discharged 
energy. In many instances, the presence of organic gas will attenuate 
the signal and mask any deeper reflections. The boomer systems will 
consist of one of the following:
    (A) An Applied Acoustics Squid 2000 mini sparker ``Boomer'': The 
maximum energy input ranges from 600 - 2,500 Joules (J) per shot with a 
maximum power input of 2,500 J per shot. The maximum energy will be 
determined once penetration has been assessed in the field. A pulse 
length range of 1 - 5 msec is typical. The peak in the source level 
beam reaches 222 dB re 1 microPa-m at 600 J with a frequency range of 
0.5 to 300 kHz.
    (B) An Applied Acoustics Model AA300 Boomer plate with housing. The 
maximum energy input is 350 J per shot with a maximum power input of 
1,000 J per shot. The maximum energy that would be used for these 
surveys is 300 J. The pulse length ranges from 150 to 400 msec with a 
reverberation of less than 1/10 of the initial pulse. The peak in the 
source level beam reaches 218 dB re 1 microPa-m at 300 J with a 
frequency range of 0.5 to 300 kHz. A Datasonics Model SPR-1200 seismic 
profiling system also known as a ``bubble pulser.'' It has an 
electromagnetic source. The frequency of the system is 400 Hz in a 
narrow band. The peak in the source-level beam reaches 200 dB re 1 
microPa-m.
     (3) Multichannel Seismic System
    The multichannel seismic system sources will consist of an:
    (A) Geo-Spark 1600 Sparker: Much like the boomer, the sparker is a 
mechanical means of generating enough sound energy to penetrate the 
subsurface sediments. The sparker has eight electrode modules which are 
evenly spaced which make up an array with a physical dimension of 1.6 x 
2 m (5.2 x 6.6 ft). The number of electrodes used is user defined, 
which gives the Geo-Spark 1600 the capability of operating at 6 - 16 
Kj. It is expected that the sparker will be operated in a range of 10- 
16 Kj. The sparker is towed behind the vessel approximately 75 ft (23 
m) on a catamaran style floatation system. The towed unit is connected 
to a Geo-Spark 16 Kj power supply located on the deck which can emit 
power output of 4000 - 16000 J. Signals from the sparker are reflected 
from the various bedding planes (density/velocity interfaces) and 
received by a multi-channel hydrophone streamer. These signal data are 
then recorded on disc or tape. The sparker can effectively detail the 
upper 1 sec of sub bottom at a peak output of 212 dB re 1 microPa. The 
depth of seismic penetration obtained with this system is determined by 
the sediment type and the amount of discharged energy.
    (B) Ultra Shallow Water (USW) array composed of a 40-in\3\ seismic 
sound source with four 10-in\3\ Input/Output (I/O) sleeve guns. If 
desired, the power can also be reduced to 20 in\3\. The reflected 
energy will be received by a multi channel marine digital recording 
streamer system with 48 hydrophone channels located at intervals of 
3.125 - 12.5 m (10 - 41 ft) along the length of the streamer. The sound 
source is expected to provide 1.5 to 3 sec of data, two-way travel time 
with a resolution of 10 msec. It operates at a frequency range of 20 to 
200 Hz and a peak sound output of 196 dB re 1 microPa for all four guns 
combined. The frequency range that will be used in the proposed surveys 
will be between 20 Hz and 200 Hz, nominal. This tool is useful in 
finding shallow faults and amplitude anomalies.

Description of Marine Mammals in the Activity Area

    In general, the marine mammal species under NMFS' management 
authority that occur in or near the proposed survey area within the 
Chukchi Sea are the bowhead (Balaena mysticetus), gray (Eschrichtius 
robustus), humpback (Megaptera novaeangliae), minke (Balaenoptera 
acutorostrata), beluga (Delphinapterus leucas), and killer whales 
(Orcinus orca); harbor porpoises (Phocoena phocoena); and the bearded 
(Erignathus barbatus), ringed (Phoca hispida), spotted (P. largha), and 
ribbon seals (P. fasciata). Among these species, the bowhead, humpback, 
and fin whales are listed as ``Endangered'' under the Endangered 
Species Act (ESA).
    A detailed description of the biology, population estimates, and 
distribution and abundance of these species is provided in CPAI's IHA 
application. Additional information regarding the stock assessments of 
these species is in NMFS' Alaska Marine Mammal Stock Assessment Report 
(Angliss and Outlaw, 2007), and can also be assessed via the following 
URL link: https://www.nmfs.noaa.gov/pr/pdfs/sars/po2006.pdf.
    ESA-listed species known to occur in the adjacent Bering Sea, 
include blue (B. musculus), North Pacific right (Eubalaena japonica), 
and sperm whales (Physeter macrocephalus); and Steller sea lion 
(Eumetopias jubatus). However, these species are considered to be 
extra-limital or rare in the Chukchi and Beaufort Seas. Fin whales have 
been recently reported in the Chukchi Sea in 2007 (Green et al., 2007), 
but there is a very remote chance of interaction and potential impact. 
Therefore, these species (Steller sea lion, and sperm, fin, blue, and 
northern right whale) are not discussed further under this IHA 
application.
    The most numerous marine mammal species seasonally occurring in the 
Chukchi Sea is the Pacific walrus (Odobenus rosmarus divergens). The 
polar bear (Ursus maritimus) is also found in the Chukchi Sea. However, 
these two marine mammal species fall under the management authority of 
the U.S. Fish and Wildlife Service (USFWS), and a separate application 
for an incidental take authorization for walrus and polar bears is 
being made to USFWS for the Chukchi Sea program.
    Additional information on those species that are under NMFS' 
management authority within or near

[[Page 30067]]

the proposed survey areas is presented below.

Bowhead Whales

    The only bowhead whale found in the proposed project areas is the 
Western Arctic stock bowhead whale, which is also known as the Bering-
Chukchi-Beaufort stock or Bering Sea stock, and they are the only 
bowhead stock present in U.S. waters. The majority of these bowhead 
whales migrates annually from wintering (November through March) areas 
in the northern Bering Sea, through the Chukchi Sea in the Spring 
(March through June), to the Beaufort Sea where they spend much of the 
summer (mid-May through September) before returning again to Bering Sea 
in the fall (September through November) to overwinter (Braham et al., 
1980; Moore and Reeves, 1993). Most of the year, bowheads are 
associated with sea ice (Moore and reeves, 1993). The bowhead spring 
migration follows fractures in the sea ice around the coast of Alaska.
    During the summer, most bowhead whales are in relatively ice-free 
waters of the Beaufort Sea. Although some bowheads are found in the 
Chukchi and Bering Seas in summer, these whales are thought to be a 
part of the expanding Western Arctic stock (Rugh et al., 2003). In the 
Beaufort sea, distribution of bowhead whales is not uniform with 
respect to depth, and they are more often observed in continental slope 
(201 - 2,000 m, or 659 - 6,562 ft, water depth) than in inner shelf ( 
<50 m or 164 ft water depth) habitat (Moore et al., 2000).
    In the fall, bowhead whales are distributed across the Beaufort and 
Chukchi seas, and are seen more often in inner and outer shelf waters 
than in slope and basin waters (Moore et al., 2000). During the fall 
migration, bowheads select shelf waters in all but ``heavy ice'' 
conditions, when they select slope habitat (Moore, 2000).
    The minimum population estimate of the Western Arctic stock of 
bowhead whales is 9,472 (Angliss and Outlaw, 2007). Raftery et al. 
(1995) reported that this bowhead stock increased at a rate of 3.1 
percent from 1978 to 1993, during which time abundance increased from 
approximately 5,000 to 8,000 whales.

Gray Whales

    Most of the Eastern North Pacific gray whales spend the summer 
feeding in the northern Bering and Chukchi Seas (Rice and Wolman, 1971; 
Berzin, 1984; Nerini, 1984). Moore et al. (2000) reported that within 
the Alaskan Arctic, gray whale summer distribution was concentrated in 
the northern Bering Sea, especially in the Chirikov Basin. In the 
Chukchi Sea, gray whale sightings were clustered along the shore, 
mostly between Cape Lisburne and Point Barrow (Moore et al., 2000). 
Reflecting this pattern of distribution, gray whales are strongly 
associated with shallow (< 35 m, or 115 ft) coastal/shoal habitat in 
the Chukchi Sea and with the somewhat deeper (36 - 50 m, or 118 - 164 
ft) Chirikov Basin shelf habitat in the northern Bering Sea (Moore et 
al., 2000). During the summer surveys, gray whales were seen in ice 
conditions to 30 percent surface cover and, more often than expected, 
in 0 - 20 percent ice habitat (Moore et al., 2000). Gray whales have 
also been reported feeding in the summer in waters off of Southeast 
Alaska, British Columbia, Washington, Oregon, and California (Rice and 
Wolman, 1871; Darling, 1984; Nerini, 1984; Rice et al., 1984).
    Each fall, gray whales migrate south along the coast of North 
America from Alaska to Baja California, in Mexico (Rice and Wolman, 
1971), most of them starting in November or December (Rugh et al., 
2001). In the Alaskan Arctic in fall, gray whale distribution in the 
Chukchi Sea is clustered near shore at Pt. Hope and between Icy Cape 
and Pt. Barrow, and in offshore waters northwest of Pt. Barrow (Hanna 
Shoal) and southwest of Pt. Hope (Moore et al., 2000). There are more 
sightings of gray whales in shelf/trough and coastal/shoal depth 
habitats than in shelf waters (Moore et al., 2000). As in summer, gray 
whales are observed far more in open water/light (0 - 30%) ice cover 
(Moore et al., 2000).
    The Eastern North Pacific gray whales winter mainly along the west 
coast of Baja California, using certain shallow, nearly landlocked 
lagoons and bays, and calves are born from early January to mid-
February (Rice et al., 1981). The northbound migration generally begins 
in mid-February and continues through May (Rice et al., 1981; 1984; 
Poole, 1984), with cows and newborn calves migrating northward 
primarily between March and June along the U.S. West Coast.
    Although twice being hunted to the brink of extinction in the mid 
1800s and again in the early 1900s, the eastern North Pacific gray 
whales population has since increased to a level that equals or exceeds 
pre-exploitation numbers (Jefferson et al., 1993). Angliss and Outlaw 
(2007) reported the latest abundance estimate of this population is 
18,178.

Humpback Whales

    The humpback whale is distributed worldwide in all ocean basins, 
though in the North Pacific region it does not usually occur in Arctic 
waters. The historic feeding range of humpback whales in the North 
Pacific encompassed coastal and inland waters around the Pacific Rim 
from Point Conception, California, north to the Gulf of Alaska and the 
Bering Sea, and west along the Aleutian Islands to the Kamchatka 
Peninsula and into the Sea of Okhotsk (Nemoto, 1957; Tomlin, 1967; 
Johnson and Wolman, 1984). A vessel survey in the central Bering Sea in 
July of 1999 documented 17 humpback whale sightings, most of which were 
distributed along the eastern Aleutian Island chain and along the U.S.-
Russia Convention Line south of St. Lawrence Island (Moore et al., 
2000). Humpback whales have been known to enter the Chukchi Sea 
(Johnson and Wolman, 1984), nonetheless, their occurrence inside the 
proposed project area is rare.
    Aerial, vessel, and photo-identification surveys and genetic 
analyses indicate that there are at least two relatively separate 
populations that migrate between their respective summer/fall feeding 
areas to winter/spring calving and mating areas are found in offshore 
and coastal waters of Alaska during certain part of the year 
(Calambokidis et al., 1997 Baker et al., 1998): the central North 
Pacific stock and the western North Pacific stock. It is unknown 
whether the animals that were occasionally sighted off Alaskan Arctic 
belong to the central or western North Pacific stock of humpback 
whales. The population estimate of the western North Pacific humpback 
whale is 394 whales; and the population estimate of the central North 
Pacific humpback whale is 4,005.

Minke Whales

    In the North Pacific, minke whales occur from the Bering and 
Chukchi seas south to near the Equator (Leatherwood et al., 1982). In 
offshore and coastal waters off Alaska, the Alaska stock of minke 
whales are relatively common in the Bering and Chukchi seas and in the 
inshore waters of the Gulf of Alaska (Mizroch, 1992). Minke whales are 
known to penetrate loose ice during the summer, and some individuals 
venture north of the Bering Strait (Leatherwood et al., 1982).
    No estimates have been made for the number of the Alaska stock of 
minke whales in the entire North Pacific (Angliss and Outlaw, 2007), 
however, a visual survey conducted in 1999 and 2000 provided 
provisional abundance estimates of 810 and 1,003 minke whales in the 
central-eastern and

[[Page 30068]]

southeastern Bering Sea, respectively (Moore et al., 2002).

Beluga Whales

    Beluga whales are distributed throughout seasonally ice-covered 
Arctic and subarctic waters of the Northern Hemisphere (Gurevich, 
1982), and are closely associated with open leads and polynyas in ice-
covered regions (Hazard, 1988). Beluga whale seasonal distribution is 
affected by ice cover, tidal conditions, access to prey, temperature, 
and human interaction (Lowry, 1985).
    Among five stocks of beluga whales that are recognized within U.S. 
waters, the eastern Chukchi Sea beluga whales occur within the proposed 
project area (Angliss and Outlaw, 2007).
    In the Alaskan Arctic in summer beluga whales are seen more often 
in continental slope (201 - 2,000 m, or or 659 - 6,562 ft, water depth) 
than in inner shelf (< 50 m or 164 ft water depth) habitat (Moore et 
al., 2000). Satellite tagging efforts directed at the eastern Chukchi 
stock of beluga whales showed that whales tagged in the eastern 
Chuckchi in summer traveled 1,100 km (684 mi) north of the Alaska 
coastline and to the Canadian Beaufort Sea within 3 months of tagging 
(Suydam et al., 2001), indicting significant stock overlap with the 
Beaufort Sea stock of beluga whales.
    During the winter, beluga whales occur in offshore waters 
associated with pack ice. In the spring, they migrate to warmer coastal 
estuaries, bays, and rivers for molting (Finley, 1982) and calving 
(Sergeant and Brodie, 1969). Annual migrations may cover thousands of 
kilometers (Reeves, 1990).
    Although population surveys were conducted in 1998 and 2002, 
several technical issues prevented an acceptable estimation of the 
population size from these two surveys. As a result, the abundance 
estimated from the 1989-91 surveys is still considered to be the most 
reliable for the eastern Chukchi Sea beluga whale stock, with an 
estimated population of 3,710 whales (Angliss and Outlaw, 2007).

Killer Whales

    Killer whales have been observed in all oceans and seas of the 
world (Leatherwood and Dahlheim, 1978). Along the west coast of North 
America, killer whales occur along the entire Alaskan coast, and 
seasonal and year-round occurrence has been noted for killer whales 
throughout Alaska (Braham and Dahlheim, 1982), including the Bering and 
southern Chukchi seas (Leatherwood et al., 1986; Lowry et al., 1987). 
However, little is known about the seasonal distribution of killer 
whales in the proposed project area in Chukchi Sea. George et al. 
(1994) cited that local hunters in Barrow, Alaska, have seen a few 
killer whales each year in the Point Barrow region during July and 
August. In addition, between 1985 and 1994, Eskimo hunters have related 
two instances of killer whales attacking and killing gray whales in the 
Chukchi Sea near Barrow (George et al., 1994).
    Studies of killer pods based on aspects of morphology, ecology, 
genetics, and behavior have provided evidence of the existence of 
``resident,'' ``offshore,'' and ``transient'' killer whale ecotypes 
(Ford and fisher, 1982; Baird and Stacey, 1988; Baird et al., 1992; 
Hoelzel et al., 1998; 2002; Barrett-Lennard, 2000).
    Off the waters of Alaska, six stocks of killer whales have been 
recognized: the Alaska resident; the northern resident; the Gulf of 
Alaska, Aleutian Islands, and Bering Sea transient; the AT1 transient; 
the West Coast transient; and the offshore stocks. It is not clear 
which stocks killer whales within the proposed project area belong to, 
however, mostly likely they are of the ``transient'' ecotype based on 
their marine mammal based diet (Ford et al., 1998; Saulitis et al., 
2000; Herman et al., 2005). The occurrence of killer whales in the 
vicinity of the proposed area is rare.
    The population size of the Gulf of Alaska, Aleutian Islands, and 
Bering Sea stock of killer whales is estimated at 314 animals.

Harbor Porpoises

    In the eastern North Pacific, the harbor porpoise ranges from Point 
Barrow, along the Alaska coast, and down the west coast of North 
America to Point Conception, California (Gaskin, 1984). Although it is 
difficult to determine the true stock structure of harbor porpoise 
populations in the northeast Pacific, from a management standpoint, it 
would be prudent to assume that regional populations exist and that 
they should be managed independently (Rosel et al., 1995; Taylor et 
al., 1996). Accordingly, three separate harbor porpoise stocks in 
Alaska are recommended based on management boundaries, with the Bering 
Sea stock occurring throughout the Aleutian Islands and all waters 
north of Unimak Pass, including the proposed project area (Angliss and 
Outlaw, 2007). Nonetheless, the occurrence of harbor porpoise within 
the proposed project area is not frequent.
    The population size of this stock is estimated at 66,078 animals 
(Angliss and Outlaw, 2007).

Ringed Seals

    Ringed seals are widely distributed throughout the Arctic basin, 
Hudson Bay and Strait, and the Bering and Baltic seas. Ringed seals 
inhabiting northern Alaska belong to the subspecies P. h. hispida, and 
they are year-round residents in the Beaufort Sea.
    The seasonal distribution of ringed seals in the Beaufort Sea is 
affected by a number of factors but a consistent pattern of seal use 
has been documented since aerial survey monitoring began over 20 years 
ago. During late April through June, ringed seals are distributed 
throughout their range from the southern ice edge northward (Braham et 
al., 1984). Recent studies indicate that ringed seals show a strong 
seasonal and habitat component to structure use (Williams et al., 
2006), and habitat, temporal, and weather factors all had significant 
effects on seal densities (Moulton et al., 2005). The studies also 
showed that effects of oil and gas development on local distribution of 
seals and seal lairs are no more than slight, and are small relative to 
the effects of natural environmental factors (Moulton et al., 2005; 
Williams et al., 2006).
    A reliable estimate for the entire Alaska stock of ringed seals is 
currently not available (Angliss and Outlaw, 2007). A minimum estimate 
for the eastern Chukchi and Beaufort Sea is 249,000 seals, including 
18,000 for the Beaufort Sea (Angliss and Outlaw, 2007). The actual 
numbers of ringed seals are substantially higher, since the estimate 
did not include much of the geographic range of the stock, and the 
estimate for the Alaska Beaufort Sea has not been corrected for animals 
missed during the surveys used to derive the abundance estimate 
(Angliss and Outlaw, 2007). Estimates could be as high as or approach 
the past estimates of 1 - 3.6 million ringed seals in the Alaska stock 
(Frost, 1985; Frost et al., 1988).

Bearded Seals

    The bearded seal has a circumpolar distribution in the Arctic, and 
it is found in the Bering, Chukchi, and Beaufort seas (Jefferson et 
al., 1993). Bearded seals are predominately benthic feeders, and prefer 
waters less than 200 m (656 ft) in depth. Bearded seals are generally 
associated with pack ice and only rarely use shorefast ice (Jefferson 
et al., 1993). Bearded seals occasionally have been observed 
maintaining

[[Page 30069]]

breathing holes in annual ice and even hauling out from holes used by 
ringed seals (Mansfield, 1967; Stirling and Smith, 1977).
    Seasonal movements of bearded seals are directly related to the 
advance and retreat of sea ice and to water depth (Kelly, 1988). During 
winter they are most common in broken pack ice and in some areas also 
inhabit shorefast ice (Smith and Hammill, 1981). In Alaska waters, 
bearded seals are distributed over the continental shelf of the Bering, 
Chukchi, and Beaufort seas, but are more concentrated in the northern 
part of the Bering Sea from January to April (Burns, 1981). Recent 
spring surveys along the Alaskan coast indicate that bearded seals tend 
to prefer areas of between 70 and 90 percent sea ice coverage, and are 
typically more abundant greater than 20 nm (37 km) off shore, with the 
exception of high concentrations nearshore to the south of Kivalina in 
the Chukchi Sea (Bengtson et al., 2000; Simpkins et al., 2003).
    There are no recent reliable population estimates for bearded seals 
in the Beaufort Sea or in the proposed project area (Angliss and 
Outlaw, 2007). Aerial surveys conducted by MMS in fall 2000 and 2001 
sighted a total of 46 bearded seals during survey flights conducted 
between September and October (Treacy, 2002a; 2002b). Bearded seal 
numbers are considerably higher in the Bering and Chukchi seas, 
particularly during winter and early spring. Early estimates of bearded 
seals in the Bering and Chukchi seas range from 250,000 to 300,000 
(Popov, 1976; Burns, 1981). There is no evidence that this stock has 
suffered significant decline over the years.

Spotted Seals

    Spotted seals occur in the Beaufort, Chukchi, Bering, and Okhotsk 
seas, and south to the northern Yellow Sea and western Sea of Japan 
(Shaughnessy and Fay, 1977). Based on satellite tagging studies, 
spotted seals migrate south from the Chukchi Sea in October and pass 
through the Bering Strait in November and overwinter in the Bering Sea 
along the ice edge (Lowry et al., 1998). In summer, the majority of 
spotted seals are found in the Bering and Chukchi seas, but do range 
into the Beaufort Sea (Rugh et al., 1997; Lowry et al., 1998) from July 
until September. The seals are most commonly seen in bays, lagoons, and 
estuaries and are typically not associated with pack ice at this time 
of the year.
    A small number of spotted seal haul-outs are documented in the 
central Beaufort Sea near the deltas of the Colville and Sagavanirktok 
rivers (Johnson et al., 1999). Previous studies from 1996 to 2001 
indicate that few spotted seals (a few tens) utilize the central Alaska 
Beaufort Sea (Moulton and Lawson, 2002; Treacy, 2002a; 2002b). In 
total, there are probably no more than a few tens of spotted seals 
along the coast of central Alaska Beaufort Sea.
    A reliable abundance estimate for spotted seal is not currently 
available (Angliss and Outlaw, 2005), however, early estimates of the 
size of the world population of spotted seals was 335,000 to 450,000 
animals and the size of the Bering Sea population, including animals in 
Russian waters, was estimated to be 200,000 to 250,000 animals (Burns, 
1973). The total number of spotted seals in Alaskan waters is not known 
(Angliss and Outlaw, 2007), but the estimate is most likely between 
several thousand and several tens of thousands (Rugh et al., 1997).

Ribbon Seals

    Ribbon seals inhabit the North Pacific Ocean and adjacent parts of 
the Arctic Ocean. In Alaska waters, ribbon seals are found in the open 
sea, on the pack ice and only rarely on shorefast ice (Kelly, 1988). 
They range northward from Bristol Bay in the Bering Sea into the 
Chukchi and western Beaufort seas. From March to early May, ribbon 
seals inhabit the Bering Sea ice front (Burns, 1970; 1981; Braham et 
al., 1984). They are most abundant in the northern part of the ice 
front in the central and western part of the Bering Sea (Burns, 1970; 
Burns et al., 1981). As the ice recedes in May to mid-July, the seals 
move farther to the north in the Bering Sea, where they haul out on the 
receding ice edge and remnant ice (Burns, 1970; 1981; Burns et al., 
1981). There is little information on the range of ribbon seals during 
the rest of the year. Recent sightings and a review of the literature 
suggest that many ribbon seals migrate into the Chukchi Sea for the 
summer (Kelly, 1988).
    A recent reliable abundance estimate for the Alaska stock of ribbon 
seals is currently not available. Burns (1981) estimated the worldwide 
population of ribbon seals at 240,000 in the mid-1970s, with an 
estimate for the Bering Sea at 90,000 - 100,000.

Potential Effects on Marine Mammals

    Operating a variety of acoustic equipment such as side-scan sonars, 
echo-sounders, bottom profiling systems, and airguns for seafloor 
imagery, bathymetry, and seismic profiling has the potential for 
adverse affects on marine mammals.

Potential Effects of Airgun Sounds on Marine Mammals

    The effects of sounds from airguns might include one or more of the 
following: tolerance, masking of natural sounds, behavioral 
disturbance, and, at least in theory, temporary or permanent hearing 
impairment, or non-auditory physical or physiological effects 
(Richardson et al., 1995)
     The potential effects of airguns discussed below are presented 
without consideration of the mitigation measures that CPAI has 
presented and that will be required by NMFS. When these measures are 
taken into account, it is unlikely that this project would result in 
temporary, or especially, permanent hearing impairment or any 
significant non-auditory physical or physiological effects.
(1) Tolerance
    Numerous studies have shown that pulsed sounds from airguns are 
often readily detectable in the water at distances of many kilometers. 
Studies have also shown that marine mammals at distances more than a 
few kilometers from operating seismic vessels often show no apparent 
response (tolerance). 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 that 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, and small odontocetes seem 
to be more tolerant of exposure to airgun pulses than are baleen 
whales.
(2) 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 very few specific data of relevance. 
Some whales are known to continue calling in the presence of seismic 
pulses. Their calls can be heard between the seismic pulses (e.g., 
Richardson et al., 1986; McDonald et al., 1995; Greene et al., 1999; 
Nieukirk et al., 2004). Although there has been one report that sperm 
whales cease calling when exposed to pulses from a very distant seismic 
ship (Bowles et al., 1994), a more recent study reports that sperm 
whales off northern Norway continued calling in the presence of seismic 
pulses (Madsen et al., 2002). That has also been shown during recent

[[Page 30070]]

work in the Gulf of Mexico (Tyack et al., 2003; Smultea et al., 2004). 
Masking effects of seismic pulses are expected to be negligible in the 
case of the smaller odontocete cetaceans, given the intermittent nature 
of seismic pulses. Dolphins and porpoises commonly are heard calling 
while airguns are operating (e.g., Gordon et al., 2004; Smultea et al., 
2004; Holst et al., 2005a; 2005b). Also, the sounds important to small 
odontocetes are predominantly at much higher frequencies than are 
airgun sounds.
(3) 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. If a marine mammal does react briefly to an underwater 
sound by slightly changing its behavior or moving a small distance, the 
impacts of the change are unlikely to be biologically significant to 
the individual, let alone the stock or the species as a whole. However, 
if a sound source displaces marine mammals from an important feeding or 
breeding area for a prolonged period, impacts on the animals could be 
significant.
(4) 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 advises against exposing cetaceans and pinnipeds 
to impulsive sounds above 180 and 190 dB re 1 microPa (rms), 
respectively (NMFS, 2000). Those thresholds have been used in defining 
the safety (shut down) radii planned for the proposed seismic surveys. 
Although those thresholds were established before there were any data 
on the minimum received levels of sounds necessary to cause temporary 
auditory impairment in marine mammals, they are considered to be 
conservative.
    Several aspects of the planned monitoring and mitigation measures 
for this project 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 (see Mitigation and Monitoring 
section below). In addition, many cetaceans are likely to show some 
avoidance of the area with high received levels of airgun sound. 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 theoretically might 
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, there is no definitive 
evidence that any of these effects occur even for marine mammals in 
close proximity to large arrays of airguns. It is unlikely that any 
effects of these types would occur during the proposed project given 
the brief duration of exposure of any given mammal, and the planned 
monitoring and mitigation measures (see below).
(5) Strandings and Mortality
    Marine mammals close to underwater detonations of high explosive 
can be killed or severely injured, and the auditory organs are 
especially susceptible to injury (Ketten et al., 1993; Ketten, 1995). 
Airgun pulses are less energetic and have slower rise times, and there 
is no evidence that they can cause serious injury, death, or stranding 
even in the case of large airgun arrays.
    Nonetheless, the airgun array proposed to be used in the proposed 
site clearance surveys in Chukchi Sea is small in volume (40 cu inches) 
and the source level is expected at 196 dB re 1 mircoPa (peak), which 
is approximately 190 dB re 1 microPa (rms). The 160, 170, and 180 dB re 
1 microPa (rms) radii, in the beam below the transducer, would be 32 m 
(104 ft), 10 m (33 ft), and 3.2 m (10 ft), respectively, for the 40-cu-
inch airgun array, assuming spherical spreading.

Possible Effects of Signals from Sonar Equipment

    While the sonar equipment proposed to be used for this project 
generates high sound energy, the equipment operates at frequencies 
(>100 kHz) beyond the effective hearing range of most marine mammals 
likely be encountered (Richardson et al., 1995). However, the equipment 
proposed for the seismic profiling operate at a frequency range and 
sound level that could affect marine mammal behavior if they occur 
within a relatively close distance to the sound source (Richardson et 
al., 1995). In addition, given the direct downward beam pattern of 
these sonar systems coupled with the high-frequency characteristics of 
the signals, the horizontal received levels of 180 and 190 dB re 1 
microPa (rms) would be much smaller when compared to those from the 
low-frequency airguns with similar source levels. Therefore, NMFS 
believes that effects of signals from sonar equipment to marine mammals 
are negligible.

Numbers of Marine Mammals Estimated to be Taken

    All anticipated takes would be takes by Level B harassment, 
involving temporary changes in behavior. The proposed mitigation 
measures to be applied would prevent the possibility of injurious 
takes.
    Take was calculated for the two areas of the study area using 
vessel-based density estimates. Few bowheads and no belugas were 
observed during the vessel surveys conducted in the Chukchi Sea by LGL 
et al. (2008), although the surveys used multiple vessels achieving 
substantial effort and coverage from early July to mid November. This 
result is generally consistent with the historic information, which 
shows that bowheads generally migrated through the Chukchi Sea to the 
Beaufort Sea by mid-late June, and don't return until about late 
October and November, probably reaching the region of the project area 
no earlier than late October (LGL et al., 2008). Similarly, most 
belugas migrate to the northern Chukchi Sea and westward into the 
Beaufort Sea by mid to late July and return to the region of the 
project area in late October and November (Suydam et al., 2005). 
Although LGL et al., (2008) did not observe belugas offshore in 2006 or 
2007, they did encounter belugas along the coast in decreasing numbers 
from July to October/November during aerial surveys. LGL et al. (2008) 
also observed bowheads in the fall near Barrow during nearshore aerial 
surveys, suggesting the whales had not moved very far into Chukchi Sea 
at that time. While these data and the historic information suggest the 
take calculations are reasonable for belugas and bowheads, the take 
numbers have been adjusted to 10 animals for each species to account 
for the possible occurrence of more animals than estimated in the 
project area during operations due to an early freeze-up or other 
unanticipated changes in the environment. This adjustment is generally 
consistent with estimates based on less current densities used in past 
IHAs for bowhead (0.0011/km\2\) and beluga (0.0034/km\2\) whales for 
late fall.

[[Page 30071]]

    The vessel-based density estimates for ringed and spotted seals 
were reported in the LGL et al. (2008) study as a combined estimate for 
the two species, since observers were not able to distinguish the two 
species in the open water. However, since typically ringed seals 
comprise almost 95 percent of the combined ringed/spotted seal 
sightings recorded during surveys in offshore waters of the Chukchi Sea 
during 1989 - 1991 were ringed seals (Brueggeman et al., 1990; 1991; 
1992), the LGL et al. (2008) ringed/spotted seal data were corrected by 
applying 95 percent of the sightings as ringed, and 5 percent as 
spotted seals, respectively.
    JASCO modeled the sound levels of different configurations of 
seismic profilers (10 kj and 16 kj sparkers, 10 in\3\ and 20 in\3\ 2-
gun arrays, 40 cu\3\ single gun, and 10 in\3\ 4-gun array) and found 
the 4-gun array produced the highest sound levels. Therefore, all take 
estimates of marine mammals are calculated for the 4-gun array in this 
proposed activity, which reaches the 160 dB re 1 microPa sound level at 
1.665 km (1.03 mi) from the source, the 180 dB re 1 microPa level at 
115 m (377 ft), and the 190 dB level at 20 m (66 ft).
    The average estimates of ``take'' were calculated by multiplying 
the expected average animal densities by the area of ensonification for 
the 160 dB re 1 microPa (rms). The area of ensonification was 
determined by multiplying the total proposed trackline of 5,300 km 
(3,294 mi)(2,120 km, or 1,318 mi, in August; 2,120 km, or 1,318 mi, in 
September; and 1,060 km, or 659 mi, in October) times 2 (both sides of 
the trackline) times the distance to the 160-dB isopleth. The distance 
to the 160-dB isopleth was estimated as approximately 1,665 m (5,463 
ft) with a corresponding area of ensonification of 17,649 km2 (6,817 
mi2).
    Based on the calculation, it is estimated that up to approximately 
10 bowhead, 37 gray, and 4 minke whales, 42 harbor porpoises, 1,379 
ringed, 72 spotted, and 376 bearded seals would be affected by Level B 
behavioral harassment as a result of the proposed shallow hazard and 
site clearance surveys. These take numbers represent 0.09, 0.19, 0.06, 
0.66, and 0.15 percent of the western Arctic stock of bowhead, eastern 
North Pacific stock of gray whales, Bering Sea stock of harbor 
porpoise, and Alaska stocks of ringed and bearded seals in the Chukchi 
Sea region, respectively. Since no accurate current population 
estimates of minke whales and spotted seals are available, a specific 
estimate of the percentage of Level B harassment of this species is 
undetermined. Nonetheless, it is very low relative to the affected 
species or stocks in the proposed project area because: (1) for the 
minke whales, the Chukchi Sea is not their typical habitat (visual 
surveys in 1999 and 2000 counted 810 and 1,003 minke whales in the 
central-eastern and southeastern Bering Sea, respectively, not 
including animals missed on the trackline, and animals submerged when 
the ship passed (Moore et al., 2002), therefore, the take estimate of 4 
minke whale is small even in relation to these visual counts); and (2) 
for the spotted seal, the early population estimate of this species 
ranged from 335,000 - 450,000 seals (Burns, 1973), and there is no 
reason to believe that the population of this species has declined 
significantly.
    In addition, a number of beluga, humpback, and killer whales, and 
ribbon seals could also be affected by Level B behavioral harassment as 
a result of the proposed marine surveys in the Chukchi Sea. However, 
since the occurrence of these marine mammals is very rare within the 
proposed project area during the late summer and fall in the Chukchi 
Sea, take numbers cannot be estimated. However, for the same reason, 
NMFS believes their take numbers would be much lower (including as a 
percentage of the affected species or stock) as compared to those 
marine mammals whose take numbers were calculated.

Potential Impacts to Subsistence Harvest of Marine Mammals

    Subsistence hunting and fishing is historically, and continues to 
be, an essential aspect of Native life, especially in rural coastal 
villages. The Inupiat participate in subsistence hunting and fishing 
activities in and around the Chukchi Sea.
    Alaska Natives, including the Inupiat, legally hunt several species 
of marine mammals. Communities that participate in subsistence 
activities potentially affected by seismic surveys within the proposed 
survey areas are Point Hope, Point Lay, Wainwright, and Barrow. Marine 
animals used for subsistence in the proposed area include: bowhead 
whales, beluga whales, ringed seals, spotted seals, bearded seals, 
Pacific walrus, and polar bears. In each village, there are key 
subsistence species. Hunts for these animals occur during different 
seasons throughout the year. Depending upon the village's success of 
the hunt for a certain species, another species may become a priority 
in order to provide enough nourishment to sustain the village.
    Point Hope residents subsistence hunt for bowhead and beluga 
whales, polar bears and walrus. Bowhead and beluga whales are hunted in 
the spring and early summer along the ice edge. Beluga whales may also 
be hunted later in the summer along the shore. Walrus are harvested in 
late spring and early summer, and polar bear are hunted from October to 
April (MMS, 2007). Seals are available from October through June, but 
are harvested primarily during the winter months, from November through 
March, due to the availability of other resources during the other 
periods of the year (MMS, 2007).
    With Point Lay situated near Kasegaluk Lagoon, the community's main 
subsistence focus is on beluga whales. Seals are available year-round, 
and polar bears and walruses are normally hunted in the winter. Hunters 
typically travel to Barrow, Wainwright, or Point Hope to participate in 
bowhead whale harvest, but there is interest in reestablishing a local 
Point Lay harvest.
    Wainwright residents subsist on both beluga and bowhead whales in 
the spring and early summer. During these two seasons the chances of 
landing a whale are higher than during other seasons. Seals are hunted 
by this community year-round and polar bears are hunted in the winter.
    Barrow residents' main subsistence focus is concentrated on 
biannual bowhead whale hunts. They hunt these whales during the spring 
and fall. Other animals, such as seals, walruses, and polar bears are 
hunted outside of the whaling season, but they are not the primary 
source of the subsistence harvest (URS Corporation, 2005).
    The potential impact of the noise produced by the proposed survey 
on subsistence could be substantial. If bowhead or beluga whales are 
permanently deflected away from their migration path, there could be 
significant repercussions to the subsistence use villages. However, 
mitigation efforts will be put into action to minimize or avoid 
completely any adverse affects on all marine mammals.
    As a mitigation measure to minimize or avoid any adverse effects to 
subsistence harvest, CPAI will meet with key native organizations 
responsible for managing marine mammals in the Arctic. In accordance 
with 50 CFR 126.104(a)(12), CPAI will meet with the Alaska Eskimo 
Whaling Commission (AEWC) in the planning for the 2008 site clearance 
and shallow hazard survey and develop a Plan of Cooperation (POC). In 
addition, CPAI will consult subsistence committees and commissions as 
required by its OCS 193 Leases, and meet with the North Slope Borough 
(NSB) as necessary. Meetings with other stakeholders will provide 
information on the time, location, and

[[Page 30072]]

features of the seismic survey/operations, opportunities for 
involvement by local people, potential impacts to marine mammals, and 
mitigation measures to avoid or minimize impacts.
    A number of actions will be taken by CPAI during the surveys to 
minimize any adverse effect on the availability of marine mammals for 
subsistence, which have been proposed in the CPAI application. They 
include the following:
    (1) Site clearance and shallow hazard surveys will occur in areas 
considerably away from the villages during the hunting periods;
    (2) Site clearance and shallow hazard surveys will follow 
procedures of changing vessel course, powering down, and shutting down 
acoustic equipment to minimize effects on the behavior of marine 
mammals and, therefore, effects on opportunities for harvest by local 
communities; and
    (3) In the unlikely event that a hunter is encountered, operations 
will be managed to stay beyond any hunter encountered within 5 km (3.1 
mi) of the vessel when shooting airguns.
    The combination of the low volume air guns, timing, location, 
mitigation measures, and input from local communities and organization 
is expected to mitigate any adverse effect of the seismic surveys on 
availability of marine mammals for subsistence uses.

Potential Impacts on Habitat

    The proposed site clearance surveys would 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 
activity would be temporarily elevated noise levels and the associated 
direct effects on marine mammals, as discussed above.

Proposed Monitoring and Mitigation Measures

Monitoring

    In order to reduce and minimize the potential impacts to marine 
mammals from the proposed site clearance surveys, NMFS proposes the 
following monitoring measures to be implemented for the proposed 
project in Chukchi Sea.
    Marine mammal monitoring during the site clearance surveys would be 
conducted by qualified, NMFS-approved marine mammal observers (MMOs). 
Vessel-based MMOs would be on board the seismic source vessel to ensure 
that no marine mammals would enter the relevant safety radii while 
noise-generating equipment is operating.
    MMOs will alternate at 4-hour shifts to avoid fatigue. The vessel 
crew will also be instructed to assist in detecting marine mammals and 
implementing mitigation requirements (if practical). Before the start 
of a geophysical survey the crew will be given additional instruction 
on how to do so.
    During daytime hours, the MMO(s) will scan the area around the 
vessel systematically with reticule binoculars (e.g., 7 50 Bushnell or 
equivalent) and with the naked eye. Laser range finders (Laser Tech 
laser rangefinder or equivalent) will also be available to assist with 
distance estimation. During darkness, NVDs (Night Vision Device) will 
be available (ATN NVG-7 or equivalent).

Mitigation

    Proposed mitigation measures include (1) vessel speed or course 
alteration, provided that doing so will not compromise operational 
safety requirements, (2) acoustic equipment shut down, and (3) acoustic 
source ramp up.
(1) Speed or Course Alteration
    If a marine mammal is detected outside the relevant safety zone but 
appears likely to enter it based on relative movement of the vessel and 
the animal, then if safety and survey objectives allow, the vessel 
speed and/or course would be adjusted to minimize the likelihood of the 
animal entering the safety zone.
(2) Shut down Procedures
    If a marine mammal is detected within, or appears likely to enter, 
the relevant safety zone of the array in use, and if vessel course and/
or speed changes are impractical or will not be effective to prevent 
the animal from entering the safety zone, then the acoustic sources 
that relate to the seismic surveys would be shut down.
    Following a shut down, acoustic equipment would not be turned on 
until the marine mammal is outside the safety zone. The animal would be 
considered to have cleared the safety zone if it (1) is visually 
observed to have left the 115-m (377-ft) or 20-m (66-ft) safety zone, 
for a cetacean or a pinniped species, respectively; or (2) has not been 
seen within the relevant safety zone for 15 min in the case of 
odontocetes or pinnipeds and 30 min in the case of mysticetes. These 
safety zones correspond to areas where the received SPLs are 180 and 
190 dB re 1 microPa (rms), respectively.
    Following a shut down and subsequent animal departure as above, the 
acoustic sources may be turned on to resume operations following ramp-
up procedures described below.
(3) Ramp-up Procedures
    A ramp-up procedure will be followed when the acoustic sources 
begin operating after a specified period without operations. It is 
proposed that, for the present survey, this period would be 30 min. 
Ramp up would begin with the power on of the smallest acoustic 
equipment for the survey at its lowest power output. The power output 
would be gradually turned up and other acoustic sources would be added 
in a way such that the source level would increase in steps not 
exceeding 6 dB per 5-min period. During ramp-up, the MMOs would monitor 
the safety zone, and if marine mammals are sighted, decisions about 
course/speed changes and/or shutdown would be implemented as though the 
acoustic equipment is operating at full power.

Data Collection and Reporting

    MMOs would record data to estimate the numbers of marine mammals 
present and to document apparent disturbance reactions or lack thereof. 
Data would be used to estimate numbers of animals potentially ``taken'' 
by harassment. They would also provide information needed to order a 
shut down of acoustic equipment when marine mammals are within or 
entering the safety zone.
    When a sighting is made, the following information about the 
sighting would be recorded:
    (1) Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from seismic vessel, and apparent 
reaction to the acoustic sources or vessel.
    (2) Time, location relative to the acoustic sources, heading, 
speed, activity of the vessel (including whether and the level at which 
acoustic sources are operating), sea state, visibility, and sun glare.
    The data listed under (2) would 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