Marine Mammals; Incidental Take During Specified Activities, 33212-33255 [E8-12918]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 73, Number 113 (Wednesday, June 11, 2008)]
[Rules and Regulations]
[Pages 33212-33255]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-12918]



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Part IV





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 18



Marine Mammals; Incidental Take During Specified Activities; Final Rule

Federal Register / Vol. 73, No. 113 / Wednesday, June 11, 2008 / 
Rules and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 18

[FWS-R7-FHC-2008-0040; 71490-1351-0000-L5]
RIN 1018-AU41


Marine Mammals; Incidental Take During Specified Activities

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: The Fish and Wildlife Service (Service or we) has developed 
regulations that authorize the nonlethal, incidental, unintentional 
take of small numbers of Pacific walruses (Odobenus rosmarus divergens) 
and polar bears (Ursus maritimus) during oil and gas industry 
(Industry) exploration activities in the Chukchi Sea and adjacent 
western coast of Alaska. This rule will be effective for 5 years from 
date of issuance. We find that the total expected takings of Pacific 
walruses (walruses) and polar bears during Industry exploration 
activities will impact small numbers of animals, will have a negligible 
impact on these species, and will not have an unmitigable adverse 
impact on the availability of these species for subsistence use by 
Alaska Natives. The regulations include: permissible methods of 
nonlethal taking; measures to ensure that Industry activities will have 
the least practicable adverse impact on the species and their habitat, 
and on the availability of these species for subsistence uses; and 
requirements for monitoring and reporting. The Service will issue 
Letters of Authorization (LOAs) to conduct activities under the 
provisions of these regulations.

DATES: This rule is effective June 11, 2008, and remains effective 
through June 11, 2013. We find that it is appropriate to make this rule 
effective immediately because it relieves restrictions that would 
otherwise apply under the Marine Mammal Protection Act and therefore 
section 553(d)(1) of the Administrative Procedure Act applies.

FOR FURTHER INFORMATION CONTACT: Craig Perham, Office of Marine Mammals 
Management, U.S. Fish and Wildlife Service, 1011 East Tudor Road, 
Anchorage, AK 99503, telephone 907-786-3810 or 1-800-362-5148, or e-
mail R7_MMM_Comment@fws.gov.

SUPPLEMENTARY INFORMATION:

Background

    Section 101(a)(5)(A) of the Marine Mammal Protection Act (MMPA) (16 
U.S.C. 1371(a)(5)(A)) gives the Secretary of the Interior (Secretary) 
through the Director of the Service (we) the authority to allow the 
incidental, but not intentional, taking of small numbers of marine 
mammals, in response to requests by U.S. citizens (you) [as defined in 
50 CFR 18.27(c)] engaged in a specified activity (other than commercial 
fishing) in a specified geographic region. According to the MMPA, we 
shall allow this incidental taking if (1) we make a finding that the 
total of such taking for the 5-year regulatory period will have no more 
than a negligible impact on these species and will not have an 
unmitigable adverse impact on the availability of these species for 
taking for subsistence use by Alaska Natives, and (2) we issue 
regulations that set forth (i) permissible methods of taking, (ii) 
means of effecting the least practicable adverse impact on the species 
and their habitat and on the availability of the species for 
subsistence uses, and (iii) requirements for monitoring and reporting. 
If we issue regulations allowing such incidental taking, we can issue 
LOAs to conduct activities under the provisions of these regulations 
when requested by citizens of the United States.
    The term ''take,'' as defined by the MMPA, means to harass, hunt, 
capture, or kill, or attempt to harass, hunt, capture, or kill any 
marine mammal. Harassment, as defined by the MMPA, for activities other 
than military readiness activities or scientific research conducted by 
or on behalf of the Federal Government, means ``any act of pursuit, 
torment, or annoyance which (i) has the potential to injure a marine 
mammal or marine mammal stock in the wild'' [the MMPA calls this 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'' [the MMPA calls this Level B 
harassment] (16 U.S.C. 1362).
    The terms ``small numbers,'' ``negligible impact,'' and 
``unmitigable adverse impact'' are defined in 50 CFR 18.27 (i.e., 
regulations governing small takes of marine mammals incidental to 
specified activities) as follows. ``Small numbers'' is defined as ``a 
portion of a marine mammal species or stock whose taking would have a 
negligible impact on that species or stock.'' ``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.'' ``Unmitigable adverse impact'' means ``an 
impact resulting from the specified activity: (1) That is likely to 
reduce the availability of the species to a level insufficient for a 
harvest to meet subsistence needs by (i) causing the marine mammals to 
abandon or avoid hunting areas, (ii) directly displacing subsistence 
users, or (iii) placing physical barriers between the marine mammals 
and the subsistence hunters; and (2) that cannot be sufficiently 
mitigated by other measures to increase the availability of marine 
mammals to allow subsistence needs to be met.''
    Industry conducts activities, such as oil and gas exploration, in 
marine mammal habitat that could result in the taking of marine 
mammals. Although Industry is under no legal requirement to obtain 
incidental take authorization, since 1991, Industry has requested, and 
we have issued regulations for, incidental take authorization for 
conducting activities in areas of walrus and polar bear habitat. We 
issued incidental take regulations for walruses and polar bears in the 
Chukchi Sea for the period 1991-1996 (56 FR 27443; June 14, 1991). In 
the Beaufort Sea, incidental take regulations have been issued from 
1993 to present: November 16, 1993 (58 FR 60402); August 17, 1995 (60 
FR 42805); January 28, 1999 (64 FR 4328); February 3, 2000 (65 FR 
5275); March 30, 2000 (65 FR 16828); November 28, 2003 (68 FR 66744); 
and August 2, 2006 (71 FR 43926). These regulations are at 50 CFR part 
18, subpart J (Sec. Sec.  18.121-18.129).

Summary of Current Request

    On August 5, 2005, the Alaska Oil and Gas Association (AOGA), on 
behalf of its members, (Agrium Kenai Nitrogen Operations, Alyeska 
Pipeline Service Company, Anadarko Petroleum Corporation, BP 
Exploration (Alaska) Inc., Chevron, Eni Petroleum, ExxonMobil 
Production Company, Flint Hills Resources, Alaska, Forest Oil 
Corporation, Marathon Oil Company, Petro-Canada (Alaska) Inc., Petro 
Star Inc., Pioneer Natural Resources Alaska, Inc., Shell Exploration & 
Production Company, Tesoro Alaska Company, and XTO Energy, Inc.) 
requested that the Service issue regulations to allow the nonlethal, 
incidental take of small numbers of walruses and polar bears in the 
Chukchi Sea for a period of 5 years. The Service requested additional 
information from AOGA regarding the nature, scope, and location of 
proposed

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activities for its analysis of potential impacts on walruses, polar 
bears, and subsistence harvests of these resources. On November 22, 
2006, Shell Offshore Inc. (SOI) provided an addendum to the AOGA 
petition describing SOI's projected activities for 2007-2012.
    On January 2, 2007, AOGA, on behalf of its members, also provided 
an addendum to its original petition referencing a Draft Environmental 
Impact Statement prepared by the Minerals Management Service (MMS) for 
the Chukchi Sea Planning Area: Oil and Gas Lease Sale 193 and Seismic 
Surveying Activities in the Chukchi Sea (Chukchi Sea DEIS). The Chukchi 
Sea DEIS included estimates of all reasonably foreseeable oil and gas 
activities associated with proposed Outer Continental Shelf (OCS) lease 
sales in the Chukchi Sea Planning Area. The AOGA petition requested 
that the Service consider activities described in the Chukchi Sea DEIS 
for the period 2007-2012. On January 2, 2007, ConocoPhillips Alaska, 
Inc. (CPAI), also provided an addendum to the original AOGA petition 
describing CPAI's projected activities from 2007-2012. The petition and 
addendums are available at: (Alaska.fws.gov/fisheries/mmm/itr.htm). The 
Chukchi Sea DEIS, referenced in the AOGA petition, has subsequently 
been finalized and is available at https://www.mms.gov/alaska/ref/
EIS%20EA/Chukchi_feis_Sale193/feis_193.htm (OCS EIS/EA MMS 2007-
026).
    The combined requests are for regulations to allow the incidental, 
nonlethal take of small numbers of walruses and polar bears in 
association with oil and gas activities in the Chukchi Sea and adjacent 
coastline projected out to the year 2012. The information provided by 
the petitioners indicates that projected oil and gas activities over 
this timeframe will be limited to exploration activities. Development 
and production activities were not considered in the requests. The 
petitioners have also specifically requested that these regulations be 
issued for nonlethal take. The petitioners have indicated that, through 
the implementation of appropriate mitigation measures, they are 
confident that no lethal take will occur.
    Prior to issuing regulations in response to this request, we must 
evaluate the level of industrial activities, their associated potential 
impacts to walruses and polar bears, and their effects on the 
availability of these species for subsistence use. All projected 
exploration activities described by SOI, CPAI, and AOGA (on behalf of 
its members) in their petitions, as well as projections of reasonably 
foreseeable activities for the period 2007-2012 described in the 
Chukchi Sea EIS were considered in our analysis. The activities and 
geographic region specified in the requests, and considered in these 
regulations are described in the ensuing sections titled ``Description 
of Geographic Region'' and ``Description of Activities.''

Description of Regulations

    The regulations are limited to the nonlethal, incidental take of 
small numbers of walruses and polar bears associated with oil and gas 
exploration activities (geophysical seismic surveys, exploratory 
drilling, and associated support activities) in the Chukchi Sea and 
adjacent coast of Alaska and would be effective for a period of up to 5 
years from the date of issuance. We assessed the geographic region, as 
outlined in the ``Description of Geographic Region,'' and the type of 
industrial activities, as outlined in the ``Description of Activities'' 
section. No development or production activities are anticipated over 
this timeframe, or included in the regulations.
    The total estimated level of activity covered by these regulations, 
as outlined in the ``Description of Activities'' section, was based on 
all projected exploration activities described by SOI, CPAI, and AOGA 
(on behalf of its members) in their petitions, as well as projections 
of reasonably foreseeable activities for the period 2007-2012 described 
in the Chukchi Sea EIS. If the level of activity is more than 
anticipated, such as additional support vessels or aircraft, more 
drilling units, or more miles of geophysical surveys, the Service must 
re-evaluate its findings to determine if they continue to be 
appropriate.
    It is important to note that these regulations do not authorize, or 
``permit,'' the actual activities associated with oil and gas 
exploration in the Chukchi Sea. Rather, they will authorize the 
nonlethal incidental, unintentional take of small numbers of walruses 
and polar bears associated with those activities based on standards set 
forth in the MMPA. The MMS, the U.S. Army Corps of Engineers (COE), and 
the Bureau of Land Management (BLM) are responsible for permitting 
activities associated with oil and gas activities in Federal waters and 
on Federal lands. The State of Alaska is responsible for permitting 
activities on State lands and in State waters.
    The regulations include permissible methods of nonlethal taking, 
measures to ensure the least practicable adverse impact on the species 
and the availability of these species for subsistence uses, and 
requirements for monitoring and reporting. The process for nonlethal 
incidental take regulations will be that persons seeking taking 
authorization for particular projects must apply for an LOA to cover 
nonlethal take associated with specified exploration activities under 
the regulations. Each group or individual conducting Industry-related 
activity within the area covered by these regulations may request an 
LOA.
    A separate LOA is mandatory for each activity, (i.e., geophysical 
survey, seismic activity, and exploratory drilling operation). We must 
receive applications for LOAs at least 90 days before the activity is 
to begin. Applicants for LOAs must submit an Operations Plan for the 
activity, a polar bear interaction plan, and a site-specific marine 
mammal monitoring and mitigation plan to monitor the effects of 
authorized activities on walruses and polar bears. A report on all 
exploration and monitoring activities must be submitted to the Service 
within 90 days after the completed activity. Details of monitoring and 
reporting requirements are further described in ``Potential Effects of 
Oil and Gas Industry Activities on Pacific Walruses and Polar Bears.''
    Depending upon the nature, timing, and location of a proposed 
activity, applicants may also have to develop a Plan of Cooperation 
(POC) with potentially affected subsistence communities to minimize 
interactions with subsistence users. The POC is further described in 
``Potential Effects of Oil and Gas Industry Activities on Subsistence 
Uses of Pacific Walruses and Polar Bears.''
    We will evaluate each request for an LOA based upon the specific 
activity and the specific location. Each authorization will identify 
allowable methods or conditions specific to that activity and location. 
For example, we will consider seasonal or location-specific 
restrictions to limit interactions between exploration activities and 
walrus aggregations, or interference with subsistence hunting 
activities. Individual LOAs will include monitoring and reporting 
requirements specific to each activity, as well as any measures 
necessary for mitigating impacts to these species and the subsistence 
use of these species. The granting of each LOA will be based on a 
determination that the total level of taking by all applicants in any 
one year is consistent with the estimated level used to make a finding 
of negligible impact and a finding of no unmitigable adverse impacts on 
the availability of

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the species or the stock for subsistence uses. We will publish in the 
Federal Register a notice of issuance of LOAs. More information on 
applying for and receiving an LOA can be found at 50 CFR 18.27(f).
    The status of polar bears range wide was reviewed for potential 
listing under the Endangered Species Act and was listed as threatened 
on May 15, 2008 (73 FR 28212). The Service conducted an intra-Service 
section 7 consultation for these regulations, which resulted in a ``no 
jeopardy'' conclusion and developed a process to incorporate section 7 
consultations under the ESA into the established framework for 
processing LOAs.

Description of Geographic Region

    These regulations will allow Industry operators to incidentally 
take small numbers of Pacific walruses and polar bears within the same 
area, hereafter referred to as the Chukchi Sea Region (Figure 1). The 
geographic area covered by the request is the continental shelf of the 
Arctic Ocean adjacent to western Alaska. This area includes the waters 
(State of Alaska and OCS waters) and seabed of the Chukchi Sea, which 
encompasses all waters north and west of Point Hope (68[deg]20'20'' N, 
-166[deg]50'40'' W, BGN 1947) to the U.S.-Russia Convention Line of 
1867, west of a north-south line through Point Barrow (71[deg]23'29'' 
N, -156[deg]28'30'' W, BGN 1944), and up to 200 miles north of Point 
Barrow. The region includes that area defined as the MMS OCS oil and 
gas Lease Sale 193 in the Chukchi Sea Planning Area. The region also 
includes the terrestrial coastal land 25 miles inland between the 
western boundary of the south National Petroleum Reserve-Alaska (NPR-A) 
near Icy Cape (70[deg]20'00'', -148[deg]12'00'') and the north-south 
line from Point Barrow. The geographic region encompasses an area of 
approximately 90,000 square miles. This terrestrial region encompasses 
a portion of the Northwest and South Planning Areas of the NPR-A. It is 
noteworthy that the north-south line at Point Barrow is the western 
border of the geographic region in the Beaufort Sea incidental take 
regulations (71 FR 43926; August 2, 2006).

Description of Activities

    This section reviews the types and scale of oil and gas activities 
projected to occur in the Chukchi Sea Region over the specified time 
period (2007-2012). This information is based upon information provided 
by the petitioners and referenced in the Chukchi Sea EIS. The Service 
has used these descriptions of activity as a basis for its findings. If 
requests for LOAs exceed the projected scope of activity analyzed under 
these regulations, the Service will reevaluate its findings to 
determine if they continue to be appropriate before further LOAs are 
issued.
    The Service does not know the specific locations where oil and gas 
exploration will occur over the proposed regulatory period. The 
location and scope of specific activities will be determined based on a 
variety of factors, including the outcome of future Federal and State 
oil and gas lease sales and information gathered through subsequent 
rounds of exploration discovery. The information provided by the 
petitioners indicates that offshore exploration activities will be 
carried out during the open water season to avoid seasonal pack ice. 
Onshore exploration activities are not expected to occur in the 
vicinity of known polar bear denning areas or coastal walrus haulouts.
    Incidental take regulations do not authorize the placement and 
location of Industry activities; they can only authorize incidental 
nonlethal take of walruses and polar bears. Allowing the activity at 
particular locations is part of the permitting process that is 
authorized by the lead permitting agency, such as the COE or BLM. The 
specific dates and durations of the individual operations and their 
geographic locations will be provided to the Service in detail when 
requests for LOAs are submitted.
    Oil and gas activities anticipated and considered in our analysis 
of incidental take regulations include: (1) Marine-streamer 3D and 2D 
seismic surveys; (2) high-resolution site-clearance surveys; (3) 
offshore exploration drilling; (4) onshore seismic exploration and 
exploratory drilling; (5) and the associated support activities for the 
afore-mentioned activities. Descriptions of these activities follow.

Marine-Streamer 3D and 2D Seismic Surveys

    Marine seismic surveys are conducted to locate geological 
structures potentially capable of containing petroleum accumulations. 
Air guns are the typical acoustic (sound) source for 2-dimensional and 
3-dimensional (2D and 3D, respectively) seismic surveys. An outgoing 
sound signal is created by venting high-pressure air from the air guns 
into the water to produce an air-filled cavity (bubble) that expands 
and contracts. A group of air guns is usually deployed in an array to 
produce a downward-focused sound signal. Air gun array volumes for both 
2D and 3D seismic surveys are expected to range from 1,800-6,000 cubic 
inches (in3). The air guns are fired at short, regular 
intervals, so the arrays emit pulsed rather than continuous sound. 
While most of the energy is focused downward and the short duration of 
each pulse limits the total energy into the water column, the sound can 
propagate horizontally for several kilometers.
    A 3D source array typically consists of two to three sub-arrays of 
six to nine air guns each, and is about 12.5-18 meters (m) long and 16-
36 m wide. The size of the source-array can vary during the seismic 
survey to optimize the resolution of the geophysical data collected at 
any particular site. Vessels usually tow up to three source arrays, 
depending on the survey-design specifications. Most 3D operations use a 
single source vessel; however, in a few instances, more than one source 
vessel may be used. The sound-source level (zero-to-peak) associated 
with typical 3D seismic surveys ranges between 233 and 240 decibels at 
1 meter (re 1 [mu]Pa at 1 m).
    The vessels conducting 3D surveys are generally 70-90 m (330-295 
ft) long. Surveys are typically acquired at a vessel speed of 
approximately 8.3 km/hour (4.5 knots). Source arrays are activated 
approximately every 10-15 seconds, depending on vessel speed. The 
timing between outgoing sound signals can vary for different surveys to 
achieve the desired ``shot point'' spacing to meet the geological 
objectives of the survey; typical spacing is 25-37.5 m (27-41 yards) 
wide. The receiving arrays could include multiple (4-16) streamer-
receiver cables towed behind the source array. Streamer cables contain 
numerous hydrophone elements at fixed distances within each cable. Each 
streamer can be 3-8 km (2-5 mi) long with an overall array width of up 
to 1,500 m (1,640 yards) between outermost streamer cables. 
Biodegradable liquid paraffin is used to fill the streamer and provide 
buoyancy. Solid/gel streamer cables also are used. The wide extent of 
this towed equipment limits both the turning speed and the area a 
vessel covers with a single pass over a geologic target. It is, 
therefore, common practice to acquire data using an offset racetrack 
pattern. Adjacent transit lines for a survey generally are spaced 
several hundred meters apart and are parallel to each other across the 
survey area. Seismic surveys are conducted day and night when ocean 
conditions are favorable, and one survey effort may continue for weeks 
or months, depending on the size of the survey. Data-acquisition is 
affected by the arrays towed by the survey vessel and weather 
conditions. Typically, data are only collected

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between 25 and 30 percent of the time (or 6-8 hours a day) because of 
equipment or weather problems. In addition to downtime due to weather, 
sea conditions, turning between lines, and equipment maintenance, 
surveys could be suspended to avoid interactions with biological 
resources. The MMS estimates that individual surveys could last between 
20-30 days (with downtime) to cover a 322 km2 (200 
mi2) area.
    Marine-streamer 2D surveys use similar geophysical-survey 
techniques as 3D surveys, but both the mode of operation and general 
vessel type used are different. The 2D surveys provide a less-detailed 
subsurface image because the survey lines are spaced farther apart, but 
they cover wider areas to image geologic structure on more of a 
regional basis. Large prospects are easily identified on 2D seismic 
data, but detailed images of the prospective areas within a large 
prospect can only be seen using 3D data. The 2D seismic-survey vessels 
generally are smaller than 3D-survey vessels, although larger 3D-survey 
vessels are also capable of conducting 2D surveys. The 2D source array 
typically consists of three or more sub-arrays of six to eight air gun 
sources each. The sound-source level (zero-to-peak) associated with 2D 
marine seismic surveys are the same as 3D marine seismic surveys (233-
240 dB re 1 [mu]Pa at 1 m). Typically, a single hydrophone streamer 
cable approximately 8-12 km long is towed behind the survey vessel. The 
2D surveys acquire data along single track lines that are spread more 
widely apart (usually several miles) than are track lines for 3D 
surveys (usually several hundred meters).
    Both 3D and 2D marine-streamer surveys require a largely ice-free 
environment to allow effective operation and maneuvering of the air gun 
arrays and long streamers. In the Chukchi Sea Region, the timing and 
areas of the surveys will be dictated by ice conditions. The data-
acquisition season in the Chukchi Sea could start sometime in July and 
end sometime in early November. Even during the short summer season, 
there are periodic incursions of sea ice, so there is no guarantee that 
any given location will be ice free throughout the survey.
    Approximately 160,934 km (100,000 line-miles) of 2D seismic surveys 
already have been collected in the Chukchi Sea program area, so the MMS 
assumes that additional geophysical surveys will be primarily 3D 
surveys focusing on specific leasing targets surrounding OCS Lease Sale 
193. The 3D surveys are likely to continue during the early phase of 
exploration when wells are drilled; however, the number of surveys is 
expected to decrease over time as data is collected over the prime 
prospects and these prospects are tested by drilling.
    Based upon information provided by the petitioners, and estimates 
prepared by the MMS in the Chukchi Sea EIS, the Service estimates that, 
in any given year during the specified timeframe (2007-2012), up to 
four seismic survey vessels could be operating simultaneously in the 
Chukchi Sea Region during the open water season. During the 2006 open 
water season, three seismic surveys were conducted, while only one 
seismic survey was conducted during the 2007 open-water season. Each 
seismic vessel is expected to collect between 3,200-14,500 km (2,000-
9,000 linear miles) of seismic survey data. Seismic surveys are 
expected to occur in open water conditions between July 1 and November 
30 each year. We estimate that each seismic survey vessel will be 
accompanied or serviced by one to three support vessels. Helicopters 
may also be used, when available, for vessel support and crew changes.

High-Resolution Site-Clearance Surveys

    Based on mapping of the subsurface structures using 2D and 3D 
seismic data, several well locations may be proposed. Prior to drilling 
deep test wells, high-resolution site clearance seismic surveys and 
geotechnical studies will be necessary to examine the proposed 
exploration drilling locations for geologic hazards, archeological 
features, and biological populations. Site clearance and studies 
required for exploration will be conducted during the open water season 
before a drill rig is mobilized to the site. A typical operation 
consists of a vessel towing an acoustic source (air gun) about 25 m 
behind the ship and a 600-m streamer cable with a tail buoy. The source 
array usually is a single array composed of one or more air guns. A 2D 
high-resolution site-clearance survey usually has a single air gun, 
while a 3D high-resolution site survey usually tows an array of air 
guns. The ships travel at 5.6-6.5 km/hour (3-3.5 knots), and the source 
is activated every 7-8 seconds (or about every 12.5 m). All vessel 
operations are designed to be ultra-quiet, as the higher frequencies 
used in high-resolution work are easily masked by the vessel noise. 
Typical surveys cover one OCS block at a time. MMS regulations require 
information be gathered on a 300-by 900-m grid, which amounts to about 
129 line kilometers of data per lease block. If there is a high 
probability of archeological resources, the north-south lines are 50 m 
apart and the 900 m remains the same.
    Including line turns, the time to survey a lease block is 
approximately 36 hours. Air gun volumes for high-resolution surveys 
typically are 90-150 in\3\, and the output of a 90-in\3\ air gun ranges 
from 229-233 dB high-resolution re 1[mu]Pa at 1m. Air gun pressures 
typically are 2,000 psi (pounds per square inch), although they can be 
used at 3,000 psi for higher signal strength to collect data from deep 
in the subsurface.
    Based upon information provided by the petitioners, and estimates 
prepared by the MMS in the Chukchi Sea EIS, we estimate that during the 
specified timeframe (2007-2012), as many as six high-resolution site 
surveys may be carried out in any given year, with the majority of site 
surveys occurring in the latter part of the regulatory time period.

Offshore Drilling Operations

    Considering water depth and the remoteness of this area, drilling 
operations are most likely to employ drill ships with ice-breaker 
support vessels. Water depths greater than 30 m (100 ft) and possible 
pack-ice incursions during the open-water season will preclude the use 
of bottom-founded platforms as exploration drilling rigs. Using drill 
ships allows the operator to temporarily move off the drill site if sea 
or ice conditions require it. Drilling operations are expected to range 
between 30 and 90 days at different well sites, depending on the depth 
to the target formation, difficulties during drilling, and logging/
testing operations. Drill ships will operate only during the open-water 
season, where drifting ice can prevent their operation.
    A drill ship is secured over the drill site by deploying anchors on 
as many as ten to twelve mooring lines. The drill pipe is encased in a 
riser that compensates for the vertical wave motion. The blowout 
preventer (BOP) is typically located at the seabed in a hole dug below 
the ice-scour depth. BOP placement is an important safety feature 
enabling the drill ship to shut down operations and get underway 
rapidly without exposing the well. One or more ice management vessels 
(ice breakers) generally support drill ships to ensure ice does not 
encroach on operations. A barge and tug typically accompany the vessels 
to provide a standby safety vessel, oil spill response capabilities, 
and refueling support. Most supplies (including fuel) necessary to 
complete drilling activities are stored on the drill ship and support 
vessels. Helicopter servicing of drill ships can occur as frequently as 
1-2 times/day. The abandonment phase is initiated if

[[Page 33216]]

exploratory wells are not successful. In a typical situation, wells are 
permanently plugged (with cement) and wellhead equipment removed. The 
seafloor site is restored to some practicable, pre-exploration 
condition. Post-abandonment surveys are conducted to confirm that no 
debris remains following abandonment or those materials remain at the 
lease tract. The casings for delineation wells are either cut 
mechanically or with explosives during the process of well abandonment. 
The MMS estimates that exploration wells will average 2,438 m (8,000 
ft), will use approximately 475 tons of dry mud, and produce 600 tons 
of dry rock cuttings. Considering the cost of synthetic drilling fluids 
now commonly used, the MMS assumes that most of the drilling mud will 
be reconditioned and reused. All of the rock cuttings will be 
discharged at the exploration site.
    Considering the relatively short open-water season in the Chukchi 
Sea (July-November), the MMS estimates that up to four wells could be 
started by one rig each drilling season. However, it is more likely 
that only one to two wells could be drilled, tested, and abandoned by 
one drill ship in any given season, leaving work on the other wells to 
the next summer season. A total of five exploration wells have been 
drilled on the Chukchi shelf, and the MMS estimates that 7 to 14 
additional wells will be needed to discover and delineate a commercial 
field.
    Based upon information provided by the petitioners, and estimates 
prepared by the MMS in the Chukchi Sea EIS, we estimate that as many as 
three drill ships could be operating in the Chukchi Sea Region in any 
given year during the specified timeframe (2007-2012), with the 
majority of exploratory drilling occurring in the latter part of the 
regulatory time period. Each drill ship could drill up to four 
exploratory or delineation wells per season. Each drill ship is likely 
to be supported by one to two ice breakers, a barge and tug, one to two 
helicopter flights per day, and one to two supply ships per week. The 
operating season is expected to be limited to the open-water season 
July 1 to November 30.

Onshore Seismic Exploration and Drilling

    CPAI's petition also describes conducting onshore seismic 
exploration and drilling over the next five years, including 
geotechnical site investigations, vibroseis, construction of ice pads, 
roads, and islands, and exploratory drilling. One of these activities 
is the Intrepid prospect, approximately 32 km (20 mi) south of Barrow.
    Geotechnical site investigations include shallow cores and soil 
borings to investigate soil conditions and stratigraphy. Geotechnical 
properties at select points may be integrated with seismic data to 
develop a regional model for predicting soil conditions in areas of 
interest.
    Vibroseis seismic operations are conducted both onshore and on 
nearshore ice using large trucks with vibrators that systematically put 
variable frequency energy into the earth. A minimum of 1.2 m (4 ft) of 
sea ice is required to support heavy vehicles used to transport 
equipment offshore for exploration activities. These ice conditions 
generally exist from January 1 until May 31. The exploration techniques 
are most commonly used on landfast ice, but they can be used in areas 
of stable offshore pack-ice. Multiple vehicles are normally associated 
with a typical vibroseis operation. One or two vehicles with survey 
crews move ahead of the operation and mark the source receiver points. 
Occasionally, bulldozers are needed to build snow ramps on the steep 
terrain or to smooth offshore rough ice within the site.
    A typical wintertime exploration seismic crew consists of 40-140 
personnel. Roughly 75 percent of the personnel routinely work on the 
active seismic crew, with approximately 50 percent of those working in 
vehicles and the remainder outside laying and retrieving geophones and 
cables.
    With the vibroseis technique, activity on the surveyed seismic line 
begins with the placement of sensors. All sensors are connected to the 
recording vehicle by multi-pair cable sections. The vibrators move to 
the beginning of the line, and recording begins. The vibrators move 
along a source line, which is at some angle to the sensor line. The 
vibrators begin vibrating in synchrony via a simultaneous radio signal 
to all vehicles. In a typical survey, each vibrator will vibrate four 
times at each location. The entire formation of vibrators subsequently 
moves forward to the next energy input point (67 m (220 ft) in most 
applications) and repeats the process. In a typical 16-to 18-hour day, 
a survey will complete 6 to 16 linear km (4-10 mi) in a 2D seismic 
operation and 24 to 64 linear km (15-40 mi) in a 3D seismic operation. 
CPAI anticipates conducting between one and five vibroseis seismic 
programs onshore within the northwest NPR-A over the next 5 years.
    CPAI also anticipates developing vertical seismic profiles (VSPs) 
to calibrate seismic and well data. Typically, VSP operations are 
staffed by less than eight people. Four or five of the operators remain 
in the vehicles (vibrators) within 1.6 to 3.2 km (1 to 2 mi) of the 
rig, while the others are located at the rig.
    On Federal lands, CPAI estimates drilling three to six onshore 
wells within the next five years. Drilling will likely include both 
well testing and VSPs. Three onshore wells are proposed for the 2007/
2008 season. Drilling operations will require an estimated 32-161 km 
(20-100 mi) of ice roads, 32-483 km (20-300 mi) of rolligon trails, one 
to four airfields approximately 1,500 m (5,000 ft) in length on lakes 
or tundra, rig storage on gravel, possibly at new sites in the 
Northwest NPR-A, one to five camps, and one to three rigs operating in 
a given year.

Existing Mitigation Measures for Oil and Gas Exploration Activities

    Measures to mitigate potential effects of oil and gas exploration 
activities on marine mammal resources and subsistence use of those 
resources have been identified and developed through previous MMS lease 
sale National Environmental Policy Act (NEPA) review and analysis 
processes. The Chukchi Sea Final EIS (CS FEIS) (https://www.mms.gov/
alaska/ref/EIS%20EA/Chukchi_feis_Sale193/feis_193.htm (OCS EIS/EA 
MMS 2007-026) identifies several existing measures designed to mitigate 
potential effects of oil and gas exploration activities on marine 
mammal resources and subsistence use of those resources (CS FEIS, 
Sections II.B.3; II-B.5-24). All plans for OCS exploration activities 
will go through an MMS review and approval to ensure compliance with 
established laws and regulations. Operational compliance is enforced 
through the MMS on-site inspection program. The following MMS lease 
sale stipulations and mitigation measures will be applied to all 
exploration activities in the Chukchi Lease Sale Planning Area and the 
geographic region of the incidental take regulations. The Service has 
incorporated these MMS Lease sale mitigation measures into their 
analysis of impacts to Pacific walruses and polar bears in the Chukchi 
Sea.
    MMS lease sale stipulations that will help minimize Industry 
impacts to Pacific walruses and polar bears include:

Oil Spill Prevention and Response

    In compliance with 30 CFR 254, Oil-Spill-Prevention and Response 
Plans and contingency actions must be prepared by lessees to address 
the

[[Page 33217]]

prevention, detection, and cleanup of fuel and oil spills associated 
with exploration operations.

Site-Specific Monitoring Program for Marine Mammal Subsistence 
Resources

    A lessee proposing to conduct exploration operations within 
traditional subsistence use areas will be required to conduct a site-
specific monitoring program designed to assess when walruses and polar 
bears are present in the vicinity of lease operations and the extent of 
behavioral effects on these marine mammals due to their operations. 
This stipulation applies specifically to the communities of Barrow, 
Wainwright, Point Lay, and Point Hope.
    Site-specific monitoring programs will provide information about 
the seasonal distributions of walruses and polar bears. The information 
can be used to improve evaluations of the threat of harm to the species 
and provides immediate information about their activities, and their 
response to specific events. This stipulation is expected to reduce the 
potential effects of exploration activities on walruses, polar bears, 
and the subsistence use of these resources. This stipulation also 
contributes incremental and important information to ongoing walrus and 
polar bear research and monitoring efforts.

Conflict Avoidance Mechanisms To Protect Subsistence-Harvesting 
Activities

    Through consultation with potentially affected communities, the 
lessee shall make every reasonable effort to assure that their proposed 
activities are compatible with marine mammal subsistence hunting 
activities and will not result in unreasonable interference with 
subsistence harvests. In the event that no agreement is reached between 
the parties, the lessee, the appropriate management agencies and co-
management organizations, and any communities that could be directly 
affected by the proposed activity may request that the MMS assemble a 
group consisting of representatives from the parties specifically to 
address the conflict and attempt to resolve the issues before the MMS 
makes a final determination on the adequacy of the measures taken to 
prevent unreasonable conflicts with subsistence harvests.
    This lease stipulation will help reduce potential conflicts between 
subsistence hunters and proposed oil and gas exploration activities. 
This stipulation will help reduce noise and disturbance conflicts from 
oil and gas operations during specific periods, such as peak hunting 
seasons. It requires that the lessee meet with local communities and 
subsistence groups to resolve potential conflicts. The consultations 
required by this stipulation ensure that the lessee, including 
contractors, consult and coordinate both the timing and sighting of 
events with subsistence users. This stipulation has proven to be 
effective in the Beaufort Sea Planning Area in mitigating offshore 
exploration activities through the development of annual agreements 
between the Alaska Eskimo Whaling Commission and participating oil 
companies.

Measures To Mitigate Seismic-Surveying Effects

    The measures summarized below are based on the protective measures 
in MMS' most recent marine seismic survey exploration permits and the 
recently completed Programmatic Environmental Assessment of Arctic 
Ocean OCS Seismic Surveys--2006 (https://www.mms.gov/alaska/ref/pea_
be.htm). As stated in the MMS Programmatic Environmental Assessment, 
these protective measures will be incorporated in all MMS-permitted 
seismic activities.
    1. Spacing of Seismic Surveys--Operators must maintain a minimum 
spacing of 15 miles between the seismic-source vessels for separate 
simultaneous operations.
    2. Exclusion Zone--A 180/190-decibel (dB) isopleth-exclusion zone 
(also called a safety zone) from the seismic-survey-sound source shall 
be free of marine mammals, including walruses and polar bears, before 
the survey can begin and must remain free of mammals during the survey. 
The purpose of the exclusion zone is to protect marine mammals from 
Level A harassment. The 180-dB (Level A harassment injury) applies to 
cetaceans and walruses, and the 190-dB (Level A harassment-injury) 
applies to pinnipeds other than walruses and polar bears.
    3. Monitoring of the Exclusion Zone--Trained marine mammal 
observers (MMOs) shall monitor the area around the survey for the 
presence of marine mammals to maintain a marine mammal-free exclusion 
zone and monitor for avoidance or take behaviors. Visual observers 
monitor the exclusion zone to ensure that marine mammals do not enter 
the exclusion zone for at least 30 minutes prior to ramp up, during the 
conduct of the survey, or before resuming seismic survey work after a 
shut down.
    Shut Down--The survey shall be suspended until the exclusion/safety 
zone is free of marine mammals. All observers shall have the authority 
to, and shall instruct the vessel operators to, immediately stop or de-
energize the airgun array whenever a marine mammal is seen within the 
zone. If the airgun array is completely shut down for any reason during 
nighttime or poor sighting conditions, it shall not be re-energized 
until daylight or whenever sighting conditions allow for the zone to be 
effectively monitored from the source vessel and/or through other 
passive acoustic, aerial, or vessel-based monitoring.
    Ramp Up--Ramp up is the gradual introduction of sound from airguns 
to deter marine mammals from potentially damaging sound intensities and 
from approaching the specified zone. This technique involves the 
gradual increase (usually 5-6 dB per 5-minute increment) in emitted 
sound levels, beginning with firing a single airgun and gradually 
adding airguns over a period of at least 20-40 minutes, until the 
desired operating level of the full array is obtained. Ramp-up 
procedures may begin after observers ensure the absence of marine 
mammals for at least 30 minutes. Ramp-up procedures shall not be 
initiated at night or when monitoring the zone is not possible. A 
single airgun operating at a minimum source level can be maintained for 
routine activities, such as making a turn between line transects, for 
maintenance needs or during periods of impaired visibility (e.g., 
darkness, fog, high sea states), and does not require a 30-minute 
clearance of the zone before the airgun array is again ramped up to 
full output.
    Field Verification--Before conducting the survey, the operator 
shall verify the radii of the exclusion/safety zones within real-time 
conditions in the field. This provides for more accurate radii rather 
than relying on modeling techniques before entering the field. Field-
verification techniques must use valid techniques for determining 
propagation loss. When moving a seismic-survey operation into a new 
area, the operator shall verify the new radii of the zones by applying 
a sound-propagation series.
    4. Monitoring of the Seismic-Survey Area--Aerial-monitoring surveys 
or an equivalent monitoring program acceptable to the Service will be 
required through the LOA authorization process. Field verification of 
the effectiveness of any monitoring techniques may be required by the 
Service.
    5. Reporting Requirements--Reporting requirements provide 
regulatory agencies with specific information on the monitoring 
techniques to be implemented and how any observed impacts to marine 
mammals will be recorded. In addition,

[[Page 33218]]

operators must immediately report to Federal regulators any shut downs 
due to a marine mammal entering the exclusion zones and provide the 
regulating agencies with information on the frequency of occurrence and 
the types and behaviors of marine mammals (if possible to ascertain) 
entering the exclusion zones.
    6. Temporal/Spatial/Operational Restrictions--Seismic-survey and 
associated support vessels shall observe an 805-m (0.5-mi) safety 
radius around walruses hauled-out onto land or ice. Aircraft shall be 
required to maintain a 305-m (1,000-ft) minimum altitude within 805 m 
(0.5 mi) of hauled-out walruses.
    7. Seismic-survey operators shall notify MMS immediately in the 
event of any loss of cable, streamer, or other equipment that could 
pose a danger to marine mammals.
    These seismic mitigation measures will help reduce the potential 
for Level A Harassment of walruses and polar bears during seismic 
operations. The spatial separation of seismic operations will also 
reduce potential cumulative effects of simultaneous operations. The 
monitoring and reporting requirements will provide location-specific 
information about the seasonal distributions of walruses and polar 
bears. The additional information can be used to evaluate the future 
threat of harm to the species and also provides immediate information 
about their activities, and their response to specific events.

Biological Information

Pacific Walruses

1. Stock Definition and Range
    Pacific walruses are represented by a single stock of animals that 
inhabit the shallow continental shelf waters of the Bering and Chukchi 
seas. The population ranges across the international boundaries of the 
United States and Russia, and both nations share common interests with 
respect to the conservation and management of this species.
    The distribution of Pacific walruses varies markedly with the 
seasons. During the late winter breeding season, walruses are found in 
areas of the Bering Sea where open leads, polynyas, or areas of broken 
pack-ice occur. Significant winter concentrations are normally found in 
the Gulf of Anadyr, the St. Lawrence Island Polynya, and in an area 
south of Nunivak Island. In the spring and early summer, most of the 
population follows the retreating pack-ice northward into the Chukchi 
Sea; however, several thousand animals, primarily adult males, remain 
in the Bering Sea, utilizing coastal haul-outs, during the ice-free 
season. During the summer months, walruses are widely distributed 
across the shallow continental shelf waters of the Chukchi Sea. 
Significant summer concentrations are normally found in the 
unconsolidated pack-ice west of Point Barrow, and along the northern 
coastline of Chukotka, Russia, near Wrangel Island. As the ice edge 
advances southward in the fall, walruses reverse their migration and 
re-group on the Bering Sea pack-ice.
    Between 1975 and 1990, aerial surveys were carried out by the 
United States and Russia at five year intervals, producing population 
estimates of: 221,350 (1975); 246,360 (1980); 234,020 (1985); and 
201,039 (1990). The estimates generated from these surveys are 
considered conservative abundance estimates and are not useful for 
detecting trends because walruses are found in large groups that are 
distributed in a non-uniform fashion. Efforts to survey the Pacific 
walrus population were suspended after 1990 due to unresolved problems 
with survey methods to address the patchy distribution of walruses and 
that resulted in population estimates with unacceptably large 
confidence intervals. In the spring of 2006, a joint U.S./Russia aerial 
survey to estimate the walrus population was carried out in the pack 
ice of the Bering Sea. This information is currently being analyzed and 
a current population estimate is expected in the near future.
    Estimating the abundance or population size of Pacific walruses has 
been an inherently problematic task. Previous efforts conducted in the 
autumn (1975, 1980, 1985, and 1990) resulted in widely varying 
estimates with high variance and low confidence limits. Accounting for 
animals using traditional haul-outs is factored into the abundance 
estimates. The 1975, 1980, and 1985 walrus surveys predominatly found 
animals over sea ice habitat. In contrast, the 1990 survey included a 
large number of walruses located on land haul-outs, predominantly in 
Russia, during a season of extreme ice recession.
    A 1975 evaluation of aerial survey methods conducted in the U.S. 
sector over the eastern half of the Chukchi Sea (5 days of effort 
covering 7,743 km and 30.2 flight hours) found walruses were unevenly 
distributed, patchy, and encountered more frequently in ice habitat 
where at least 75 percent of the surface was covered by ice. Estimates 
of abundance, based on single day density estimates, ranged from 818 to 
1,760 walruses in the open-water area, and 2,475 to 100,568 walruses in 
pack ice sampled areas.
    In 1980, a coordinated U.S. and Russian aerial survey found 
walruses located throughout the area surveyed and the U.S. distribution 
showed extreme clustering of walruses on pack ice in an area of high 
density between longitude 166[deg] W and 171[deg] W. Initially the 
estimates were 140,000 animals in the U.S. and 130,000 to 150,000 
animals in Russia, with a final total estimate of 246,360 animals.
    In 1985, the third joint walrus survey found few walruses in the 
U.S. sector east of 161[deg] or west of 170[deg]. On days when more 
walruses were in the water, they were found farther into the pack ice, 
and on days when nearly all walruses were hauled out on the ice, they 
were close to the southern edge of the ice. The estimate of abundance 
for the U.S. portion of the survey was 63,487 animals with an 
additional 15,238 animals, mainly males, estimated in Bristol Bay, far 
to the south. The Russians estimated either 54,080 or 115,531 walruses 
in the pack ice of their sector, depending on the inclusion or 
exclusion of a large aggregation of walruses encountered on survey 
transects from the abundance estimate. This illustrates the symptomatic 
nature of clustered or patchy distributions of walruses noted earlier 
and the consequence on abundance estimates. In addition, the Russians 
counted 39,572 animals on their Bering Sea land haul-outs. The combined 
U.S. and Russia estimate was 234,020 animals.
    In 1990, a fourth joint survey was designed to employ a common 
survey design. Unlike other surveys, the study area was unexpectedly 
characterized by an extreme amount of open water caused by an unusual 
recession of pack ice. As a result, the survey covered land haul-outs 
in the U.S. and Russia as well as open water and pack ice. The total 
combined population estimate was 201,039. Of this total, the U.S. 
sector was comprised of 7,522 walruses in Bristol Bay haul-outs and 
only 16,489 estimated in the Chukchi Sea area. This estimate differs 
dramatically from previous pack ice estimates in the U.S. Chukchi Sea 
region, where walruses were relatively abundant in previous surveys. 
The vast majority of walruses were located in the Russian sector 
(154,225 walruses) and occupied land haul-outs, including 112,848 
animals on Wrangel Island. Land haul-outs in Kamchatka, Southern 
Chukotka, the Gulf of Anadyr, and the north shore of Chukotka accounted 
for the remaining 41,377 animals. The Russian pack ice

[[Page 33219]]

was remarkably sparse with an estimate of only 16,484 animals.
2. Habitat
    Walruses are an ice dependent species. They rely on floating pack-
ice as a substrate for resting and giving birth. Walruses generally 
require ice thicknesses of 50 centimeters (cm) or more to support their 
weight. Although walruses can break through ice up to 20 cm thick, they 
usually occupy areas with natural openings and are not found in areas 
of extensive, unbroken ice. Thus, their concentrations in winter tend 
to be in areas of divergent ice flow or along the margins of persistent 
polynyas. Concentrations in summer tend to be in areas of 
unconsolidated pack-ice, usually within 100 km of the leading edge of 
the ice pack. When suitable pack-ice is not available, walruses haul 
out to rest on land. Isolated sites, such as barrier islands, points, 
and headlands, are most frequently occupied. Social factors, learned 
behavior, and proximity to their prey base are also thought to 
influence the location of haul-out sites. Traditional walrus haul-out 
sites in the eastern Chukchi Sea include Cape Thompson, Cape Lisburne, 
and Icy Cape. In recent years, the Cape Lisburne haul-out site has seen 
regular use in late summer. Numerous haul-outs also exist along the 
northern coastline of Chukotka, and on Wrangel and Herald islands, 
which are considered important haul-out areas in late summer, 
especially in years when the pack-ice retreats beyond the continental 
shelf. Notably, during the 1990 population survey, when the Chukchi Sea 
was largely ice-free, large haul-outs of walruses (over 100,000 
animals) formed on Wrangel Island. In contrast, walruses observed 
during the 1970 though 1985 aerial surveys were seen primarily on sea 
ice over the continental shelf between Wrangel Island and Alaska.
    Although capable of diving to deeper depths, walruses are for the 
most part found in shallow waters of 100 m or less, possibly because of 
higher productivity of their benthic foods in shallower water. They 
feed almost exclusively on benthic invertebrates although Native 
hunters have also reported incidences of walruses preying on seals. 
Prey densities are thought to vary across the continental shelf 
according to sediment type and structure. Preferred feeding areas are 
typically composed of sediments of soft, fine sands. The juxtaposition 
of ice over appropriate depths for feeding is especially important for 
females with dependent calves that are not capable of deep diving or 
long exposure in the water. The mobility of the pack-ice is thought to 
help prevent walruses from overexploiting their prey resource.
    Although walruses may range some distance from land or ice haul-
outs, for example during migrations or foraging excursions, the species 
is not adapted to a pelagic existence. Foraging trips can sometimes 
last up to several days, during which time they dive to the bottom 
nearly continuously. Most foraging dives to the bottom last between 5 
and 10 minutes, with a relatively short (1-2 minute) surface interval.
3. Life History
    Walruses are long-lived animals with low rates of reproduction. 
Females reach sexual maturity at 4 to 9 years of age. Males become 
fertile at 5 to 7 years of age; however, they are usually unable to 
compete for mates until they reach full physical maturity at 15-16 
years of age. Breeding occurs between January and March in the pack-ice 
of the Bering Sea. Calves are usually born in late April or May the 
following year during the northward migration from the Bering Sea to 
the Chukchi Sea. Calving areas in the Chukchi Sea extend from the 
Bering Strait to latitude 70 [deg]N. Calves are capable of entering the 
water shortly after birth, but tend to haul-out frequently, until their 
swimming ability and blubber layer are well developed. Newborn calves 
are tended closely. They accompany their mother from birth and are 
usually not weaned for 2 years or more. Cows brood neonates to aid in 
their thermoregulation, and carry them on their back or under their 
flipper while in the water. Females with newborns often join together 
to form large ``nursery herds''. Summer distribution of females and 
young walruses is closely tied to the movements of the pack-ice 
relative to feeding areas. Females give birth to one calf every 2 or 
more years. This reproductive rate is much lower than other pinniped 
species; however, some walruses live to age 35-40, and remain 
reproductively active until relatively late in life.
    Walruses are extremely social and gregarious animals. They tend to 
travel in groups and haul-out onto ice or land in groups. Walruses 
spend approximately one-third of their time hauled out onto land or 
ice. Hauled-out walruses tend to lie in close physical contact with 
each other. Youngsters often lie on top of the adults. The size of the 
hauled-out groups can range from a few animals up to several thousand 
individuals.
4. Mortality
    Polar bears are known to prey on walrus calves, and killer whales 
(Orcinus orca) have been known to take all age classes of animals. 
Predation levels are thought to be highest near terrestrial haul-out 
sites where large aggregations of walruses can be found; however, few 
observations of killer whales preying on walruses exist.
    Pacific walruses have been hunted by coastal Natives in Alaska and 
Chukotka for thousands of years. Exploitation of the Pacific walrus 
population by Europeans has also occurred in varying degrees since 
first contact. Presently, walrus hunting in Alaska and Chukotka is 
restricted to meet the subsistence needs of aboriginal peoples. Over 
the past decade, the combined harvest of the United States and Russia 
has averaged approximately 5,500 walruses per year. This mortality 
estimate includes corrections for under-reported harvest and struck and 
lost animals.
    Intraspecific trauma is also a known source of injury and 
mortality. Disturbance events can cause walruses to stampede into the 
water and have been known to result in injuries and mortalities. The 
risk of stampede-related injuries increases with the number of animals 
hauled out. Calves and young animals at the perimeter of these herds 
are particularly vulnerable to trampling injuries.
5. Distributions and Abundance of Pacific Walruses in the Chukchi Sea
    Walruses are seasonably abundant in the Chukchi Sea. Their 
distribution in the region is influenced primarily by the distribution 
and extent of seasonal pack-ice. In May and June walruses migrate into 
the region along lead systems that form along the coastlines of Alaska 
and Chukotka. During the summer months walruses are widely distributed 
along the southern margin of the seasonal pack-ice both in U.S. and 
Russian waters. During August, the edge of the pack-ice generally 
retreats northward to about 71 [deg]N, but in light ice years, the ice 
edge can retreat beyond 76 [deg]N. The sea ice normally reaches its 
minimum (northern) extent in September. In recent years, several tens 
of thousands of walruses have been reported congregating at coastal 
haul-outs along the Russian coast in late summer. Russian biologists 
attribute the formation of these coastal aggregations to diminishing 
sea ice habitats in offshore regions. In 2007, a new sea ice minima 
record was established. Sea ice had completely retreated from the 
continental shelf waters of the Chukchi Sea by mid-August, 2007 and 
anecdotal

[[Page 33220]]

reports from Russia indicate that as many as 100,000 walruses, 
comprised of mixed herds of females and calves, congregated at coastal 
haul-outs along the northern Chukotka coastline. An estimated 2,000 to 
5,000 walruses were also observed along the Alaskan Chukchi Sea coast 
in 2007 using nontraditional haul-outs. This is a relatively small 
portion of the annual, hauled-out animals in the population. 
Historically, approximately 5,000 animals have annually used the 
Bristol Bay haul-outs, such as Round Island and Cape Seniavin. The 
pack-ice usually advances rapidly southward in October, and most 
walruses move into the Bering Sea by mid-to-late November.
    Walrus are closely associated with sea ice. The dynamic nature of 
sea ice habitats is expected to result in considerable seasonal and 
annual variation in the number of animals likely to be present in the 
proposed exploration arena. While a recent abundance estimate for the 
number of walruses likely to be present in the offshore waters of the 
eastern Chukchi Sea during the proposed exploration season is not 
available, an aerial survey was carried out in the fall of 1990 during 
a season of minimum ice conditions where sea ice retracted north beyond 
the continental shelf, similar to recent conditions throughout the 
Chukchi Sea. This survey observed 16,489 walruses distributed along the 
Chukchi Sea pack-ice between Wrangel Island and Point Barrow, where a 
much larger portion of the population was distributed in Russia on land 
and sea ice haul-outs. The sea ice was distributed well beyond the 
continental shelf at the time of the survey and most walruses were 
using coastal haul-outs in Russia, which is similar to the pattern of 
distribution observed in 2007.

Polar Bears

1. Alaska Stock Definition and Range
    Polar bears occur throughout the Arctic. The world population 
estimate of polar bears ranges from 20,000-25,000 individuals. In 
Alaska, they have been observed as far south in the eastern Bering Sea 
as St. Matthew Island and the Pribilof Islands. However, they are most 
commonly found within 180 miles of the Alaskan coast of the Chukchi and 
Beaufort seas, from the Bering Strait to the U.S./Canada border. Two 
stocks occur in Alaska: (1) The Chukchi-Bering seas stock (CS); and (2) 
the Southern Beaufort Sea stock (SBS). A summary of the Chukchi and 
Southern Beaufort Sea polar bear stocks is described below. A detailed 
description of the Chukchi Sea and Southern Beaufort Sea polar bear 
stocks can be found in the ``Range-Wide Status Review of the Polar Bear 
(Ursus maritimus)'' (https://alaska.fws.gov/fisheries/mmm/polarbear/
issues.htm).
A. Chukchi/Bering Seas Stock (CS)
    The CS is defined as those polar bears inhabiting the area as far 
west as the eastern portion of the Eastern Siberian Sea, as far east as 
Point Barrow, and extending into the Bering Sea, with its southern 
boundary determined by the extent of annual ice. Based upon telemetry 
studies, the western boundary of the population has been set near 
Chaunskaya Bay in northeastern Russia. The eastern boundary is at Icy 
Cape, Alaska, which was, until recently, also considered to be the 
western boundary of the SBS. This eastern boundary constitutes a large 
overlap zone with bears in the SBS population. The CS population 
appeared to increase after the level of harvest was reduced in 1972. 
However, harvest records suggest that the population now may be 
declining. Illegal polar bear hunting in Russia is thought to be one 
reason for this decline. The most recent population estimate for the CS 
population is 2,000 animals. This was based on extrapolation of aerial 
den surveys from the early 1990s; however, this estimate is currently 
considered to be of little value for management. Reliable estimates of 
population size based upon mark and recapture are not available for 
this region and measuring the population size remains a research 
challenge due to the movements of the polar bear and the dynamic Ar