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CFR Citation: 50 CFR Part 18

FWS ID: [FWS-R7-FHC-2008-0040; 71490-1351-0000-L5]

RIN ID: RIN 1018-AU41

NOTICE: Part IV

DOCUMENT ACTION: Final rule.

SUBJECT CATEGORY: Marine Mammals; Incidental Take During Specified Activities

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.

DOCUMENT 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.

SUMMARY: Interior Department, Fish and Wildlife Service,

SUPPLEMENTAL INFORMATION

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 5year 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 19911996 (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. 18.12118.129).

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, PetroCanada (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 20072012.

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 20072012. On January 2, 2007, ConocoPhillips Alaska, Inc. (CPAI), also provided an addendum to the original AOGA petition describing CPAI's projected activities from 20072012. 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 http://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 20072012 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 20072012 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 reevaluate 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 Industryrelated 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 sitespecific 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 locationspecific 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 intraService 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 northsouth 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 ReserveAlaska (NPRA) near Icy Cape (70[deg]20'00'', 148[deg]12'00'') and the northsouth 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 NPRA. It is noteworthy that the northsouth 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 (20072012). 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) Marinestreamer 3D and 2D seismic surveys; (2) highresolution siteclearance surveys; (3) offshore exploration drilling; (4) onshore seismic exploration and exploratory drilling; (5) and the associated support activities for the aforementioned activities. Descriptions of these activities follow. MarineStreamer 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 2dimensional and 3dimensional (2D and 3D, respectively) seismic surveys. An outgoing sound signal is created by venting highpressure air from the air guns into the water to produce an airfilled cavity (bubble) that expands and contracts. A group of air guns is usually deployed in an array to produce a downwardfocused sound signal. Air gun array volumes for both 2D and 3D seismic surveys are expected to range from 1,8006,000 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 subarrays of six to nine air guns each, and is about 12.518 meters (m) long and 16 36 m wide. The size of the sourcearray 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 surveydesign specifications. Most 3D operations use a single source vessel; however, in a few instances, more than one source vessel may be used. The soundsource level (zerotopeak) 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 7090 m (330295 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 1015 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 2537.5 m (2741 yards) wide. The receiving arrays could include multiple (416) streamer receiver cables towed behind the source array. Streamer cables contain numerous hydrophone elements at fixed distances within each cable. Each streamer can be 38 km (25 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. Dataacquisition 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 68 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 2030 days (with downtime) to cover a 322 km² (200 mi²) area.

Marinestreamer 2D surveys use similar geophysicalsurvey techniques as 3D surveys, but both the mode of operation and general vessel type used are different. The 2D surveys provide a lessdetailed 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 seismicsurvey vessels generally are smaller than 3Dsurvey vessels, although larger 3Dsurvey vessels are also capable of conducting 2D surveys. The 2D source array typically consists of three or more subarrays of six to eight air gun sources each. The soundsource level (zerotopeak) 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 812 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 marinestreamer surveys require a largely icefree 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 linemiles) 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 (20072012), 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 openwater season. Each seismic vessel is expected to collect between 3,20014,500 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. HighResolution SiteClearance 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, highresolution 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 600m streamer cable with a tail buoy. The source array usually is a single array composed of one or more air guns. A 2D highresolution siteclearance survey usually has a single air gun, while a 3D highresolution site survey usually tows an array of air guns. The ships travel at 5.66.5 km/hour (33.5 knots), and the source is activated every 78 seconds (or about every 12.5 m). All vessel operations are designed to be ultraquiet, as the higher frequencies used in highresolution 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 300by 900m grid, which amounts to about 129 line kilometers of data per lease block. If there is a high probability of archeological resources, the northsouth 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 highresolution surveys typically are 90150 in\3\, and the output of a 90in\3\ air gun ranges from 229233 dB highresolution 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 (20072012), as many as six highresolution 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 icebreaker support vessels. Water depths greater than 30 m (100 ft) and possible packice incursions during the openwater season will preclude the use of bottomfounded 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 openwater 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 icescour 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 12 times/day. The abandonment phase is initiated if
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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, preexploration condition. Postabandonment 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 openwater season in the Chukchi Sea (JulyNovember), 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 (20072012), 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 openwater 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 packice. 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 40140 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 multipair 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 16to 18hour day, a survey will complete 6 to 16 linear km (410 mi) in a 2D seismic operation and 24 to 64 linear km (1540 mi) in a 3D seismic operation. CPAI anticipates conducting between one and five vibroseis seismic programs onshore within the northwest NPRA 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 32161 km (20100 mi) of ice roads, 32483 km (20300 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 NPRA, 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) (http://www.mms.gov/ alaska/ref/EIS%20EA/Chukchi_feis_Sale193/feis_193.htm (OCS EIS/EA MMS 2007026) 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; IIB.524). 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 onsite 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, OilSpillPrevention and Response Plans and contingency actions must be prepared by lessees to address the
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prevention, detection, and cleanup of fuel and oil spills associated with exploration operations.
SiteSpecific 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.

Sitespecific 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 SubsistenceHarvesting 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 SeismicSurveying 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 Surveys2006 (http://www.mms.gov/alaska/ref/pea_ be.htm). As stated in the MMS Programmatic Environmental Assessment, these protective measures will be incorporated in all MMSpermitted seismic activities.

1. Spacing of Seismic SurveysOperators must maintain a minimum spacing of 15 miles between the seismicsource vessels for separate simultaneous operations.

2. Exclusion ZoneA 180/190decibel (dB) isoplethexclusion zone (also called a safety zone) from the seismicsurveysound 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 180dB (Level A harassment injury) applies to cetaceans and walruses, and the 190dB (Level A harassmentinjury) applies to pinnipeds other than walruses and polar bears.

3. Monitoring of the Exclusion ZoneTrained marine mammal observers (MMOs) shall monitor the area around the survey for the presence of marine mammals to maintain a marine mammalfree 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 DownThe 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 reenergized 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 vesselbased monitoring.

Ramp UpRamp 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 56 dB per 5minute increment) in emitted sound levels, beginning with firing a single airgun and gradually adding airguns over a period of at least 2040 minutes, until the desired operating level of the full array is obtained. Rampup procedures may begin after observers ensure the absence of marine mammals for at least 30 minutes. Rampup 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 30minute clearance of the zone before the airgun array is again ramped up to full output.

Field VerificationBefore conducting the survey, the operator shall verify the radii of the exclusion/safety zones within realtime 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 seismicsurvey operation into a new area, the operator shall verify the new radii of the zones by applying a soundpropagation series.

4. Monitoring of the SeismicSurvey AreaAerialmonitoring 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 RequirementsReporting 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,
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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 RestrictionsSeismicsurvey and associated support vessels shall observe an 805m (0.5mi) safety radius around walruses hauledout onto land or ice. Aircraft shall be required to maintain a 305m (1,000ft) minimum altitude within 805 m (0.5 mi) of hauledout walruses.

7. Seismicsurvey 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 locationspecific 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 packice 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 packice northward into the Chukchi Sea; however, several thousand animals, primarily adult males, remain in the Bering Sea, utilizing coastal haulouts, during the icefree 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 packice 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 regroup on the Bering Sea packice.

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 nonuniform 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 haulouts 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 haulouts, 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 openwater 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 haulouts. 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 haulouts 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 haulouts 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 haulouts, including 112,848 animals on Wrangel Island. Land haulouts 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
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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 packice, usually within 100 km of the leading edge of the ice pack. When suitable packice 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 haulout areas in late summer, especially in years when the packice retreats beyond the continental shelf. Notably, during the 1990 population survey, when the Chukchi Sea was largely icefree, large haulouts 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 packice 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 (12 minute) surface interval. 3. Life History

Walruses are longlived 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 1516 years of age. Breeding occurs between January and March in the packice 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 packice 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 3540, and remain reproductively active until relatively late in life.

Walruses are extremely social and gregarious animals. They tend to travel in groups and haulout onto ice or land in groups. Walruses spend approximately onethird of their time hauled out onto land or ice. Hauledout walruses tend to lie in close physical contact with each other. Youngsters often lie on top of the adults. The size of the hauledout 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 haulout 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 underreported 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 stampederelated 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 packice. 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 packice both in U.S. and Russian waters. During August, the edge of the packice 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 haulouts 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 midAugust, 2007 and anecdotal
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reports from Russia indicate that as many as 100,000 walruses, comprised of mixed herds of females and calves, congregated at coastal haulouts 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 haulouts. This is a relatively small portion of the annual, hauledout animals in the population. Historically, approximately 5,000 animals have annually used the Bristol Bay haulouts, such as Round Island and Cape Seniavin. The packice usually advances rapidly southward in October, and most walruses move into the Bering Sea by midtolate 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 packice between Wrangel Island and Point Barrow, where a much larger portion of the population was distributed in Russia on land and sea ice haulouts. The sea ice was distributed well beyond the continental shelf at the time of the survey and most walruses were using coastal haulouts 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 20,00025,000 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 ChukchiBering 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 ``RangeWide Status Review of the Polar Bear (Ursus maritimus)'' (http://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 Arctic habitat.

Legal harvesting activities for the CS stock are currently restricted to Native Alaskans in western Alaska, as long as this does not affect the sustainability of the polar bear population. In Alaska, average annual harvest levels declined by approximately 50 percent between the 1980s and the 1990s and have remained at low levels in recent years. We believe there are several factors affecting the harvest level of CS bears in western Alaska. Substantial illegal harvest in Chukotka is the most relevant factor affecting the CS population level. In recent years a reportedly sizable illegal harvest has occurred in Russia, despite a ban on hunting that has been in place since 1956. In addition, other factors such as climatic change and its effects on packice distribution, as well as changing demographics and hunting effort in Native communities could influence the population and the declining take. The unknown rate of illegal take makes a stable designation for the CS population uncertain and tentative.

Until recently, the United States and Russia have managed the shared CS polar bear population independently. Now, Alaska and Russian bear researchers and managers are working to update and enhance the collective knowledge of polar bears in the CS stock to improve management goals and objectives. On September 21, 2007, the United States ratified the U.S./Russia Bilateral Polar Bear Conservation Agreement (Bilateral Agreement) for the shared polar bear population, which had been signed by both countries on October 16, 2000; implementing legislation for the agreement occurred in January 2007. The purpose of the Bilateral Agreement is to assure longterm, science based conservation of the polar bear population and includes binding harvest limits. Implementation of the Bilateral Agreement will unify management regimes and provide for harvest limits. The treaty calls for the active involvement of Native people and their organizations in future management programs. It will also enhance such longterm joint efforts as conservation of ecosystems and important habitats, harvest allocations based on sustainability, collection of biological information, and increased consultation and cooperation with state, local, and private interests.

In association with the ratification of the agreement, the Service sponsored a meeting from August 7 through 9, 2007, of technical specialists from the United States and Russia to discuss future management, research, and conservation needs for the CS polar bear population. The goals of the meeting were to exchange information about current and future research activities and priorities, provide technical input concerning research and management needs for the implementation of the Bilateral Agreement with specific regard to field research and conservation practices, and to initiate planning for managing the subsistence harvest in Alaska and Russia under the newly activated treaty. The primary challenge discussed by the group is the lack of populati

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 9077863810 or 18003625148, or e mail R7_MMM_Comment@fws.gov.