Marine Mammals; Incidental Take During Specified Activities, 30670-30700 [E7-10509]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 72, Number 105 (Friday, June 1, 2007)]
[Proposed Rules]
[Pages 30670-30700]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-10509]



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Part II





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; Proposed 
Rule

Federal Register / Vol. 72, No. 105 / Friday, June 1, 2007 / Proposed 
Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 18

RIN 1018-AU41


Marine Mammals; Incidental Take During Specified Activities

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule; notice of proposed incidental harassment 
authorization; request for comments.

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SUMMARY: The Fish and Wildlife Service (Service) proposes regulations 
that would authorize the nonlethal, incidental, unintentional take of 
small numbers of Pacific walruses (walruses) and polar bears during 
year-round oil and gas industry (Industry) exploration activities in 
the Chukchi Sea and adjacent western coast of Alaska. We are proposing 
that this rule be effective for 5 years from date of issuance. We 
propose a finding that the total expected takings of walruses and polar 
bears during oil and gas industry exploration activities 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 that we propose to issue 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. If the proposed regulations are issued, we can issue Letters 
of Authorization to conduct activities under the provisions of these 
regulations when requested by citizens of the United States. We are 
seeking public comments on this proposed rule.
    In addition, the Service proposes to issue authorizations to take 
small numbers of marine mammals by harassment incidental to conducting 
exploration activities during the 2007 open-water season for oil and 
gas operators (Incidental Harassment Authorization). These activities 
will be carried out from approximately July 1 through November 30, 
2007. The authorizations we propose to issue will also 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. We are seeking public comments on this proposal.

DATES: Comments on this proposed rule, the proposed issuance of 
incidental harassment authorization, and the draft Environmental 
Assessment, must be received by July 2, 2007. Comments on the 
information collection requirements must be submitted on or before July 
31, 2007.

ADDRESSES: You may submit comments by any of the following methods for 
the proposed rule, identified by RIN 1018-AU41, or for the incidental 
harassment authorization:
     Mail: Craig Perham, Office of Marine Mammals Management, 
U.S. Fish and Wildlife Service, 1011 East Tudor Road, Anchorage, AK 
99503.
     Fax: 907-786-3816.
     Hand Delivery/Courier: Office of Marine Mammals 
Management, U.S. Fish and Wildlife Service, 1011 East Tudor Road, 
Anchorage, Alaska 99503.
     E-mail: R7--MMM--Comment@fws.gov. Please submit Internet 
comments as an ASCII file avoiding the use of special characters and 
any form of encryption. Please also include ``Attn: RIN 1018-AU41'' in 
the subject line and your name and return address in your Internet 
message. If you do not receive a confirmation from the system that we 
have received your Internet message, contact us directly at U.S. Fish 
and Wildlife Service, Office of Marine Mammals Management, 907-786-3810 
or 1-800-362-5148.
    Comments on the proposed rule, identified by RIN 1018-AU41, may 
also be submitted by the following method:
     Federal eRulemaking Portal: https://www.regulations.gov. 
Follow the instructions for submitting comments.
    Please indicate to which action, RIN 1018-AU41 or incidental 
harassment authorization, your comments apply.

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 regulations allowing such incidental taking are issued, we can issue 
Letters of Authorization (LOA) 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).
    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

[[Page 30671]]

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. 
Incidental take regulations for walruses and polar bears in the Chukchi 
Sea were issued previously for the period 1991-1996 (56 FR 27443; June 
14, 1991). In the Beaufort Sea, incidental take regulations have been 
issued previously 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).

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 promulgate 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 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 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 includes 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, is available at: https://www.mms.gov/
alaska (OCS EIS/EA MMS 2006-060).
    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 offshore and onshore 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. Industry has indicated 
that, through implementation of the mitigation measures, it is 
confident a lethal take will not occur.
    Prior to issuing regulations at 50 CFR part 18, subpart I 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 DEIS 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.''
    This proposed rule also serves as the proposed incidental 
harassment authorization (IHA) under section 101(a)(5)(D) of the MMPA. 
If this proposed rule is finalized, incidental take of small numbers of 
polar bears and walrus resulting from oil and gas exploration 
activities in the Chukchi Sea will be authorized under LOAs issued 
pursuant to section 101(a)(5)(A) of the MMPA. However, operators are 
proposing to begin oil and gas exploration activities in July of 2007, 
which will likely be before the Service makes a final determination 
under the section 101(a)(5)(A) regulatory process. Therefore, this 
proposed rule also serves as the proposed IHA that, if finalized, will 
authorize the incidental take by harassment of small numbers of 
walruses and polar bears from oil and gas exploration activities in the 
Chukchi Sea during the 2007 exploration season.
    The proposed rule can serve as both the proposed rule under section 
101(a)(5)(A) and the proposed IHA under section 101(a)(5)(D) because 
the standards are the same and the procedures are compatible. 
Incidental take authorization is available under both provisions if the 
Service finds that the anticipated take will have a negligible impact 
on the species or stock and will not have an unmitigable adverse impact 
on the availability of the species or stock for subsistence uses. Both 
types of authorization would include permissible methods of taking and 
other means of effecting the least practicable impact on the species or 
stock and its habitat and on the availability of the species or stock 
for taking for subsistence uses, any measures necessary to ensure no 
unmitigable adverse impact on the availability of the species or stock 
for taking for subsistence uses, and requirements for monitoring and 
reporting of any taking that does occur.
    The differences between the two provisions are procedural. A final 
IHA would be issued without further notice in the Federal Register, 
following consideration of all comments received during the public 
comment period, if the Service finds that the anticipated level of take 
meets the statutory standards. An IHA can only be issued for up to one 
year, compared to the five-year period of the regulatory process. Also, 
an IHA can only be issued if the Service finds that no lethal take is 
likely to occur as a result of the anticipated oil and gas exploration 
activities. Here the Service would be issuing an IHA for the 2007 
exploration season. If a final rule is published in the Federal 
Register finding that the anticipated take during the full five-year 
period meets the statutory standards, Letters of Authorization will 
replace the one-year IHA that will be issued to operators if the 
Service makes final determinations that the take that is anticipated to 
result from the 2007 activities meets the statutory standards.

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    The Description of Activities section of the proposed rule 
describes the oil and gas exploration activities that will occur during 
the 2007 season, as well as during the consecutive years of the 
regulatory period. The Description of Geographic Region section 
describes the geographic area in which exploration activities will be 
conducted in 2007, as well as during the other years of the regulatory 
period. The Mitigation Measures for Oil and Gas Exploration Activities 
section describes the mitigating measures and monitoring and reporting 
requirements that will be required in 2007 as conditions of the IHA. 
The potential Effects of Oil and Gas Industry Activities on Pacific 
Walruses and Polar Bears section, the Potential Effects of Oil and Gas 
Industry Activities on Subsistence Uses of Pacific Walruses and Polar 
Bears section, and the Summary of Take Estimated for Pacific Walruses 
and Polar Bears section analyze the type and level of take of polar 
bears and walrus that is anticipated to occur during the 2007 
exploration season, as well as during the other years of the regulatory 
period. The public comment period announced with this proposed rule 
also serves as the public comment period for the proposed IHA. If the 
Service makes a final determination that the anticipated level of take 
meets the standards under section 101(a)(5)(D) of the MMPA, it will 
issue an IHA with all required conditions to oil and gas operators for 
the 2007 exploration season no later than 45 days after the close of 
the comment period.

Description of Regulations

    The proposed 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. 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 were assessed in these regulations. No development or 
production activities are anticipated over this timeframe, or 
considered in the proposed 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 DEIS referenced by the petitioners. 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 would reevaluate its findings to determine if they continue 
to be appropriate.
    It is important to note that these regulations would not authorize, 
or ``permit,'' the actual activities associated with oil and gas 
exploration in the Chukchi Sea. Rather, they would 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 petition does not request promulgation of 
regulations for the incidental taking from development or production 
activities in the Chukchi Sea. The MMS, the U.S. Army Corps of 
Engineers, 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 that we propose to issue 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. If we 
issue final nonlethal incidental take regulations, persons seeking 
taking authorization for particular projects must apply for an LOA to 
cover nonlethal take associated with specified exploration activities 
pursuant to the regulations. Each group or individual conducting an oil 
and gas industry-related activity within the area covered by these 
regulations may request an LOA.
    A separate LOA will be required for each geophysical survey or 
seismic activity and each exploratory drilling operation. Applications 
for LOAs must be received 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 be required 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.''
    Each request for an LOA will be evaluated based upon the specific 
activity and the specific location, and 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 the species or the stock for subsistence uses. 
Notice of issuance of LOAs will be published in the Federal Register. 
More information on applying for and receiving an LOA can be found at 
50 CFR 18.27(f).

Description of Geographic Region

    These regulations would allow Industry 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 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

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(70[deg]20'00'', -148[deg]12'00) and the north-south line from Point 
Barrow. The geographic region encompasses an area of approximately 
5,850 square miles. This terrestrial region encompasses a portion of 
the Northwest and South Planning Areas of the NPR-A. 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 DEIS. The Service 
has used these estimated levels of activity as a basis for its 
findings. If requests for LOAs exceed the highest estimated level of 
activity, the Service would reevaluate its findings to determine if 
they continue to be appropriate before further LOAs are issued. 
Specific locations where oil and gas activity may occur over the 
proposed regulatory period are largely speculative, but are within the 
geographic region identified and analyzed in these regulations. They 
will be determined, in part, on the outcome of future Federal and State 
oil and gas lease sales. 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 proposed incidental take regulations include: (1) Marine-streamer 3D 
and 2D seismic surveys; (2) high-resolution site-clearance surveys; (3) 
offshore exploration drilling; and (4) onshore seismic exploration and 
drilling.

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) 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. 
The size of individual air guns can range from tens to several hundred 
cubic inches (in3). 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 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 long. 
Surveys are typically acquired at a vessel speed of approximately 4.5 
knots (k) (8.3 km/hour). 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 either 25 or 37.5 m. 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 long 
with an overall array width of up to 1,500 m 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 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 200 square mile (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.
    Marine seismic-exploration work is expected to occur in the Chukchi 
Sea Region in the summer of 2007 in anticipation of OCS lease sale 193. 
This work is likely to include 3D seismic surveys, but will not include 
exploration drilling. Approximately 100,000 line-miles of 2D seismic 
surveys already have been collected in the Chukchi Sea program area, so 
the

[[Page 30674]]

MMS assumes that additional geophysical surveys will be primarily 3D 
surveys focusing on specific leasing targets. 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 DEIS, 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. Each seismic vessel is 
expected to collect between 3,200-14,500 linear kilometers 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 1-3 
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 3-3.5 knots (5.6-6.5 km/hour), 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 in3, and the 
output of a 90-in3 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 DEIS, 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.

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 100 feet 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, and the suspended well is controlled by 
blowout-prevention equipment installed on wellheads on the seabed. 
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 operate only during the open-water season, and 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 
(icebreakers) 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 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 8,000 ft, will use approximately 
475 tons (ton = 2,000 pounds) 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 5 exploration wells have been 
drilled on the Chukchi shelf, and the MMS estimates that 7-14 
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 DEIS, we estimate that as many 
as five drill-ships could be operating in the Chukchi Sea Region in any 
given year during the specified timeframe (2007-2012). Each drill-ship 
is expected to drill up to four exploratory or delineation wells per 
season. Each drill-ship is likely to be supported by 1-2 ice breakers, 
a barge and tug, 1-2 helicopter flights per day, and 1-2 supply ships 
per week. The operating season is expected to be limited to the open-
water season July 1-November 30.

Onshore Seismic Exploration and Drilling

    The CPAI 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.
    Geotechnical site investigations include shallow cores and soil 
borings

[[Page 30675]]

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 1 January until 31 May. The exploration techniques 
are most commonly used on landfast ice, but they can be used in areas 
of stable offshore pack ice. Several 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. VSP operations are usually staffed 
by less than eight people. Four or five of the operators remain in the 
vehicles (vibrators) within 1.6 to 3.2 km (1-2 mi) of the rig, while 
the others are located at the rig.
    CPAI proposes to drill up to three onshore exploration wells on 
private lands south of Barrow near the North Slope Boroughs Walakpa gas 
field in the winter of 2007. It is estimated that another 3 to 5 wells 
could be drilled in this area within the next 5 years. In support of 
these activities, CPA estimates that the following associated 
infrastructure would be required: 20-100 miles of ice roads; 20-300 
miles of rolligon trails; 1 to 2 airfields of approximately 5,000 feet 
in size; storage of rigs and/or support equipment in Barrow; and 
barging of equipment to and from Barrow from existing facilities.
    On Federal lands, CPAI estimates drilling 3 to 6 onshore wells 
within the next 5 years. Drilling will likely include both well testing 
and VSPs. Three onshore wells are proposed for 2007. Drilling 
operations will require an estimated 20 to 100 miles of ice roads, 20 
to 300 miles of rolligon trails, 1 to 4 airfields approximately 5,000 
ft in length on lakes or tundra, rig storage on gravel, possibly at new 
sites in the Northwest NPR-A, 1 to 5 camps, and 1 to 3 rigs operating 
in a given year.

Mitigation Measures for Oil and Gas Exploration Activities in the 
Chukchi Sea

    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 DEIS (https://www.mms.gov/alaska/ref/
EIS%20EA/draft_arctic_peis/draft_peis.htm) 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 (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 walrus 
and polar bears in the Chukchi Sea.
    MMS lease sale stipulations that will help minimize Industry 
impacts to Pacific walruses and polar bears include:

Pre-Booming Requirements for Fuel Transfers

    Fuel transfers of 100 barrels or more will require pre-booming of 
fuel barges. A fuel barge must be surrounded by an oil-spill-
containment boom during the entire transfer operation to help reduce 
any adverse effects from a fuel spill. Pre-booming requirements are 
intended to lower the potential effects to water quality, lower 
trophic-level organisms, marine mammals, subsistence resources and 
hunting, and sociocultural systems by providing additional protection 
from potential fuel spills.
    By containing any spill within the boom area, this stipulation will 
reduce the risk of fuel spills contacting walruses and polar bears, and 
the risk that harvested animals may become tainted from a potential 
spill.

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 evaluate 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

[[Page 30676]]

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 Outer Continental Shelf Seismic Surveys--2006 (https://
www.mms.gov/alaska/ref/pea_be.htm). As stated in the MMS Programmatic 
Environmental Assessment, these protective measures would 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, operators must report 
immediately any shutdowns 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 a 0.5-mile (~800-meter) safety 
radius around walruses hauled-out onto land or ice. Aircraft shall be 
required to maintain a 1,000-foot minimum altitude within 0.5 miles of 
hauled-out walruses.
    7. Seismic-survey operators shall notify MMS 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 walrus (Odobenus rosmarus divergens) are represented by a 
single stock of animals that inhabit the shallow

[[Page 30677]]

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.
    Several decades of intense commercial exploitation in the late 
1800s and early 1900s left the population severely depleted. The 
population is believed to have increased substantially in size and 
range during the 1960s-1980s due to hunting restrictions enacted in the 
United States and Russia that reduced the size of the commercial 
harvest and provided protection to female walruses and calves. 
Information concerning population size and trend after 1985 is less 
certain. An aerial survey flown in 1990 produced a population estimate 
of 201,039 animals; however, large confidence intervals associated with 
that estimate precluded any conclusions concerning population trend. 
The current size and trend of the Pacific walrus population are 
unknown. Projected ecosystem changes across the Arctic further 
underscore the need for detailed population studies from which sound 
management decisions can be made.
    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, polynas, or areas of broken 
pack-ice occur. Significant winter concentrations are normally found in 
the Gulf of Anadyr, the St. Lawrence Island Polyna, 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 haulouts 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 in the vicinity of Wrangel Island. As the ice 
edge advances southward in the fall, walruses reverse their migration 
and re-group on the Bering Sea pack-ice.
2. Habitat
    Walruses 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 polynas. 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 haulout sites. 
Traditional walrus haulout sites in the eastern Chukchi Sea include 
Cape Thompson, Cape Lisburne, and Icy Cape. In recent years, the Cape 
Lisburne haulout site has seen regular use in late summer. Numerous 
haulouts also exist along the northern coastline of Chukotka, and on 
Wrangel and Herald islands, which are considered important hauling 
grounds in September, especially in years when the pack-ice retreats 
far to the north.
    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. Foraging 
trips may last for 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. The intensive tilling of the sea floor by foraging walruses 
is thought to have significant influence on the ecology of the Bering 
and Chukchi Seas. Foraging activity recycles large quantities of 
nutrients from the sea floor back into the water column, provides food 
for scavenger organisms, and contributes greatly to the diversity of 
the benthic community.
3. Life History
    Walruses are long-lived animals with low rates of reproduction. 
Females reach sexual maturity at 4-9 years of age. Males become fertile 
at 5-7 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 haulout 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 two 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 (Ursus maritimus) 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 haulout sites where large aggregations of walruses can be 
found; however, few observations exist for off-shore environs.
    Pacific walruses have been hunted by coastal Natives in Alaska and 
Chukotka for thousands of years. Exploitation of the Pacific walrus 
population by

[[Page 30678]]

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. The combined harvest of 
the United States and Russia averages 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 is thought to be influenced primarily by the extent of the 
seasonal pack-ice, although habitat use patterns are poorly known. In 
May and June, most of the Pacific walrus population migrates through 
the Bering Strait into the Chukchi Sea. Walruses tend to migrate into 
the Chukchi Sea along lead systems that develop along the northwest 
coast of Alaska. Walruses are expected to be closely associated with 
the southern edge of the seasonal pack-ice during the open water 
season. By July, large groups of walruses, up to several thousand 
animals, can be found along the edge of the pack ice between Icy Cape 
and Point Barrow. 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. It is unclear how walruses 
respond in years when the sea ice retreats beyond the relatively 
shallow continental shelf waters. At least some animals are thought to 
migrate west towards Chukotka, while others have been observed hauling 
out along the shoreline between Point Barrow and Cape Lisburne. The 
pack-ice rapidly advances southward in October, and most animals are 
thought to have returned to the Bering Sea by early November.
    A recent abundance estimate for the number of walruses present in 
the Chukchi Sea during the proposed operating season is lacking. 
Previous aerial surveys of the region carried out in the 1980s resulted 
in abundance estimates ranging from 62,177-101,213. A 1990 aerial 
survey reported 16,489 walruses distributed in the Chukchi Sea pack-ice 
between Wrangel Island and Point Barrow; however, the sea-ice was 
distributed well beyond the continental shelf at the time of the 
survey. These abundance estimates are all considered conservative 
because no corrections were made for walruses in water (not visible) at 
the time of the surveys.

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 Canadian 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 are 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 Sea Stock (CS)
    The CS is defined as polar bears inhabiting the area