Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Polar Bear (Ursus maritimus, 56058-56086 [E9-25876]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 74, Number 208 (Thursday, October 29, 2009)]
[Proposed Rules]
[Pages 56058-56086]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-25876]



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Part V





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



Endangered and Threatened Wildlife and Plants; Designation of Critical 
Habitat for the Polar Bear (Ursus maritimus) in the United States; 
Proposed Rule

Federal Register / Vol. 74, No. 208 / Thursday, October 29, 2009 / 
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R7-ES-2009-0042]
[92210-1117-0000-FY09-B4]
RIN 1018-AW56


Endangered and Threatened Wildlife and Plants; Designation of 
Critical Habitat for the Polar Bear (Ursus maritimus) in the United 
States

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
designate critical habitat for polar bear (Ursus maritimus) populations 
in the United States under the Endangered Species Act of 1973, as 
amended (Act). In total, approximately 519,403 square kilometers 
(km\2\) (200,541 square miles (mi\2\)) fall within the boundaries of 
the proposed critical habitat designation. The proposed critical 
habitat is located in Alaska and adjacent territorial and U.S. waters.

DATES: We will consider comments we receive on or before December 28, 
2009. We must receive requests for public hearings, in writing, at the 
address shown in the FOR FURTHER INFORMATION CONTACT section by 
December 14, 2009. Due to the court-ordered deadline of June 30, 2010, 
to complete the final determination on this proposed designation of 
critical habitat for the polar bear, we request that you submit 
comments and information to us as soon as possible in order to allow us 
adequate time to take them into consideration for the final 
determination.

ADDRESSES: You may submit comments by one of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov. Follow the instructions for submitting comments.
     U.S. mail or hand-delivery: Public Comments Processing, 
Attn: FWS-R7-ES-2009-0042; Division of Policy and Directives 
Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, 
Suite 222; Arlington, VA 22203.
    We will post all comments on https://www.regulations.gov. This 
generally means that we will post any personal information you provide 
us (see the Public Comments section below for more information).
    You can view detailed, colored maps of areas proposed as critical 
habitat in this proposed rule at https://alaska.fws.gov/fisheries/mmm/polarbear/criticalhabitat.htm. You can obtain hard copies of maps by 
contacting the Marine Mammals Management Office (see FOR FURTHER 
INFORMATION CONTACT).

FOR FURTHER INFORMATION CONTACT: Thomas J. Evans, Marine Mammals 
Management Office, U.S. Fish and Wildlife Service, 1011 East Tudor 
Road, Anchorage, AK 99503; telephone 907/786-3800; facsimile 907/786-
3816. If you use a telecommunications device for the deaf (TDD), call 
the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Public Comments

    We intend that any final action resulting from this proposed rule 
will be based on the best scientific data available and will be as 
accurate and as effective as possible. Therefore, we request comments 
or information from the public, other concerned government agencies, 
the scientific community, industry, or other interested party 
concerning this proposed rule. We particularly seek comments 
concerning:
    (1) The reasons why we should or should not designate habitat as 
``critical habitat'' under section 4 of the Act (16 U.S.C. 1531 et 
seq.), including whether there are threats to the species from human 
activity, the degree of which can be expected to increase due to the 
designation, and whether that increase in threat outweighs the benefit 
of designation, such that the designation of critical habitat is 
prudent.
    (2) Specific information on:
     The amount and distribution of habitat used by polar bear 
populations in the United States, specifically in the southern 
Beaufort, Chukchi, and Bering Seas
     What areas occupied at the time of listing that contain 
features essential for the conservation of the species we should 
include in the designation and why, and
     What areas not occupied at the time of listing, within the 
jurisdiction of the United States, are essential to the conservation of 
the species and why.
    (3) Land use designations and current or planned activities in the 
subject areas and their possible impacts on features essential to the 
conservation of the species within proposed critical habitat.
    (4) Any foreseeable economic, national security, or other potential 
impacts resulting from the proposed designation and, in particular, any 
impacts on small entities, and the benefits of including or excluding 
areas that exhibit these impacts. Such impacts could include any 
potential impacts on oil and gas development and exploration. For more 
information on the expected effects of oil and gas development and 
exploration on critical habitat, and thus potential impacts of the 
designation on these activities, please see (among other sections) the 
sections entitled ``Petroleum Hydrocarbons'', ``Summary of 
Anthropogenic Threats to Features Essential to the Conservation of the 
Polar Bear Which May Require Special Management Considerations or 
Protection'', ``Application of the `Adverse Modification' Standard'', 
and ``Exclusions Based on Economic Impacts''.
    (5) Potential effects on oil and gas development and exploration 
including those related to impacts referenced in (4).
    (6) Potential effects on native cultures and villages.
    (7) Potential effects on commercial shipping through the Northern 
Sea Route in anticipation of a longer navigable season.
    (8) Special management considerations or protections that the 
proposed critical habitat may require.
    (9) Specific information on the incremental effects of the 
designation of critical habitat for the polar bear, in particular, will 
any aspect of the proposed critical habitat designation result in 
consultations under section 7 of the Act with a different set of 
protections than those afforded by the Marine Mammal Protection Act 
(MMPA) (16 U.S.C. 1361 et seq.)?
    (10) Whether we could improve or modify our approach to designating 
critical habitat in any way to provide for greater public participation 
and understanding, or to better accommodate public concerns and 
comments.
    We are additionally asking the public for specific information 
concerning potential denning habitat for the polar bears along the west 
coast of Alaska from Barrow southward to the Seward Peninsula. These 
specific questions and discussion are found in the Criteria Used To 
Identify Critical Habitat section of this proposed rule under the 
discussion of terrestrial denning habitat criteria.
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in the ADDRESSES section.
    If you submit a comment via https://www.regulations.gov, your entire 
comment--including any personal identifying information--will be posted 
on the website. If you submit a hardcopy comment that includes personal 
identifying information, you may request at the top of your document

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that we withhold this information from public review. However, we 
cannot guarantee that we will be able to do so. We will post all 
hardcopy comments on https://www.regulations.gov.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection on https://www.regulations.gov, or by 
appointment, during normal business hours, at the U.S. Fish and 
Wildlife Service, Marine Mammals Management Office (see FOR FURTHER 
INFORMATION CONTACT).

Background

    On May 15, 2008 (73 FR 28212), the final rule listing the polar 
bear as a threatened species under the Act was published in the Federal 
Register. In that final rule, we made our determination on the status 
of the species under the Act. On the basis of a review of the best 
available science and commercial information related to polar bear 
biology, ecology, and threats, including climate change, as discussed 
in the final listing rule, we determined the polar bear to meet the 
definition of a threatened species under the Act. Please refer to our 
final listing rule for a more detail discussion of the biology of the 
species, threats to it and its habitat, and a discussion of the effects 
of climate change on its habitat. When a species is listed as 
threatened or endangered, we are to propose critical habitat for the 
species to the maximum extent prudent and determinable based on the 
best available scientific data. In our final listing rule, we 
determined that the designation of critical habitat was prudent, but 
not determinable at that time. We have since determined that critical 
habitat is determinable and are proposing its designation in this rule. 
In this proposed rule, it is our intent to discuss only those topics 
directly relevant to the designation of critical habitat. Information 
on polar bear biology and ecology that is directly relevant to 
designation of critical habitat is discussed under the Primary 
Constituent Elements section below.
General Overview
    Polar bears are distributed throughout the ice-covered waters of 
the circumpolar Arctic (Stirling 1988, p. 61). However, in accordance 
with the regulations at 50 CFR 424.12(h), we do not designate critical 
habitat within foreign countries or in other areas outside of United 
States jurisdiction. In the United States, polar bears occur in Alaska 
and adjacent State, Territorial, and U.S. waters. Therefore, these are 
the only areas we considered including in this proposed critical 
habitat designation.
    Delineation of critical habitat requires, within the geographical 
area occupied by the polar bear, identification of the physical and 
biological features essential to the conservation of the species that 
may require special management or protection. In general terms, 
physical and biological features essential to the conservation of the 
polar bear include: (1) Annual and perennial marine sea-ice habitats 
that serve as a platform for hunting, feeding, traveling, resting, and 
(to a limited extent) denning; and (2) terrestrial habitats used by 
polar bears for denning and reproduction, as well as for seasonal use 
in traveling or resting. The most important polar bear life functions 
that occur in these habitats are feeding and reproduction. Adult female 
polar bears are the most important reproductive cohort in the 
population.
    Polar bears live in an extremely dynamic sea-ice environment. Much 
of polar bear range in the United States includes two major categories 
of sea ice: land-fast ice and pack ice. When we refer to sea-ice 
habitat in this proposed rule, we are referring to both these types of 
ice. Land-fast ice is either frozen to land or to the benthos (bottom 
of the sea) and is relatively immobile throughout the winter. Shore-
fast ice, a type of land-fast ice also known as ``fast ice,'' is 
defined by the Arctic Climate Impact Assessment (2005, p. 190) as ice 
that grows seaward from a coast and remains stationary throughout the 
winter and that is typically stabilized by grounded pressure ridges at 
its outer edge. Pack ice consists of annual and heavier multi-year ice 
that is in constant motion due to winds and currents. It is located in 
pelagic (open ocean) areas and, unlike land-fast ice, can be highly 
dynamic. The actions of winds, currents, and temperature result in the 
formation of leads (linear openings or cracks in the sea ice), pressure 
ridges, and ice floes of various sizes. While the composition of land-
fast ice is uniform, regions of pack ice can consist of various ages 
and thicknesses, from new ice only days old that may be several 
centimeters (inches) thick, to multiyear ice that has survived several 
years and may be more than 2 meters (6.56 feet (ft)) thick. Polar bear 
use of these habitats may be influenced by several factors and the 
interaction among these factors, including: (1) Water depth; (2) 
atmospheric and oceanic currents or events; (3) climate phenomena such 
as temperature, winds, precipitation, and snowfall; (4) proximity to 
the continental shelf; (5) topographic relief (which influences 
accumulation of snow for denning); (6) presence of undisturbed 
habitats; (7) secure resting areas that provide refuge from extreme 
weather, other bears, or humans; and (8) prey availability.
    Unlike some other marine mammal species, polar bears generally do 
not occur at high densities in specific areas such as rookeries and 
haulout sites. However, some denning areas, referred to as core denning 
areas, have a history of higher use by polar bears. In addition, 
terrestrial coastal areas are experiencing increasing use by polar 
bears for longer durations during the fall open-water period (the 
season when there is a minimum amount of ice present, which occurs 
during the period from when the sea ice melts and retreats during the 
summer, to the beginning of freeze-up during the fall) (Schliebe et al. 
2008, p. 2).
    As polar bears evolved from brown bears (Ursus arctos), they became 
increasingly specialized for hunting seals from the surface of the sea 
ice (Stirling 1974, p. 1,193; Smith 1980, p. 2,206; Stirling and 
[Oslash]ritsland 1995, p. 2,595). Currently, little is known about the 
dynamics of ice seal populations (seals that rely on sea ice for their 
life history functions) in the Arctic or threats to these populations. 
However, the status of the populations of the primary species of ice 
seals in the Arctic is currently being investigated by the National 
Oceanic and Atmospheric Administration, National Marine Fisheries 
Service. We do know, however, that polar bears require sea ice as a 
platform from which to search for and hunt these seals. Polar bear 
movements are influenced by the accessibility of seals, their primary 
prey. The formation and movement patterns of sea ice strongly influence 
the distribution and accessibility of ringed seals (Phoca hispida), the 
main prey for polar bears, and bearded seals (Erignathus barbatus), a 
less-used prey species. When the annual sea ice begins to form in the 
shallower water over the continental shelf, polar bears that had 
retreated north of the continental shelf during the summer return to 
the shallower shelf waters where seal densities are higher (Durner et 
al. 2009a, p. 55). During the winter period, when energetic demands are 
the greatest, nearshore lead systems and ephemeral (may close during 
the winter) or recurrent (open throughout the winter) polynyas (areas 
of open sea surrounded by sea ice) are important for seals, and are 
thus important foraging habitat for polar bears. During the spring 
period, nearshore lead systems continue to be important hunting and 
foraging habitat for polar bears. The shore-fast ice zone,

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where ringed seals construct subnivean (in or under the snow) birth 
lairs for pupping, is also an important foraging habitat during the 
spring (Stirling et al. 1993, p. 20). Polar bears in the southern 
Beaufort Sea reach their peak weights during the fall and early winter 
period (Durner and Amstrup 1996, p. 483). Thus, availability and 
accessibility of prey during this time may be critical for survival 
through the winter.
    In northern Alaska, denning habitat is more diffuse than in other 
areas where high-density denning by polar bears has been identified 
(Amstrup 2003, p. 595). In Alaska, certain areas, such as barrier 
islands (linear features of low-elevation land adjacent to the main 
coastline that are separated from the mainland by bodies of water), 
river bank drainages, much of the North Slope coastal plain, and 
coastal bluffs that occur at the interface of mainland and marine 
habitat, receive proportionally greater use for denning than other 
areas (Durner et al. 2003; Durner et al. 2006a). Snow cover, both on 
land and on sea ice, is an important component of polar bear habitat in 
that it provides insulation and cover for polar bear dens (Durner et 
al. 2003, p. 60). Geographic areas containing physical features 
suitable for snow accumulation and denning by polar bears have been 
delineated on the North Slope for an area from the Colville River Delta 
at Prudhoe Bay, Alaska, to the Canadian border (Durner et al. 2001, p. 
119; Durner et al. 2003, p. 60).
Description and Taxonomy
    Polar bears are the largest of the living bear species (Demaster 
and Stirling 1981, p. 1; Stirling and Derocher 1990, p. 190) and are 
the only bear species that is evolutionarily adapted to the arctic sea-
ice and marine habitat. Using movement patterns, tag returns from 
harvested animals, and, to a lesser degree, genetic analysis, Aars et 
al. (2006, pp. 33-47) determined that polar bears occur in 19 
relatively discrete populations. Genetic analyses have reinforced the 
observed boundaries between some designated populations (Paetkau et al. 
1999, p. 1,571; Amstrup 2003, p. 590), while confirming overlap among 
others (Paetkau et al. 1999, p. 1,571; Amstrup et al. 2004a, p. 676; 
Amstrup et al. 2005, p. 252; Cronin et al. 2006, p. 656). Currently, 
there are two polar bear populations in the United States as defined 
under the Marine Mammal Protection Act (MMPA): the southern Beaufort 
Sea population, which extends into Canada; and the Chukchi and Bering 
Seas population, which extends into the Russian Federation (Russia) 
(Figure 1) (Amstrup et al. 2004a, p. 670). Although the two U.S. 
populations are not distinguishable genetically (Paetkau et al. 1999, 
p. 1576; Cronin et al. 2006, p. 658), the population boundaries are 
thought to be ecologically meaningful and distinct enough to be used 
for management. The Service listed the polar bear as a threatened 
species throughout the Arctic under the Act on May 15, 2008 (73 FR 
28212; final rule available at https://alaska.fws.gov/fisheries/mmm/polarbear/issues.htm).
BILLING CODE 4310-55-S

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[GRAPHIC] [TIFF OMITTED] TP29OC09.023

BILLING CODE 4310-55-C
    Figure 1. Approximate bounds (95 percent contour) for the southern 
Beaufort Sea and the Chukchi and Bering Seas populations based on 
satellite radio-telemetry locations from 1985-2003.

    Polar bears are characterized by large body size, a stocky form, 
and fur color that varies from white to yellow. They are sexually 
dimorphic; females weigh 181 to 317 kilograms (kg) (400 to 700 pounds 
(lbs)), and males weigh up to 654 kg (1,440 lbs). Polar bears have a 
longer neck and a proportionally smaller head than other members of the 
bear family (Ursidae), and are missing the distinct shoulder hump 
common to brown bears. The nose, lips, and skin of polar bears are 
black (Demaster and Stirling 1981, p. 1; Amstrup 2003, p. 588).
    Polar bears evolved in sea-ice habitats for over 200,000 years and 
as a result are evolutionarily adapted to this environment (Talbot and 
Shields, 1996, p. 490). Adaptations unique to polar bears include: (1) 
white pelage with water-repellent guard hairs and dense under-fur; (2) 
a short, furred snout; (3) small ears with reduced surface area; (4) 
teeth specialized for a carnivorous rather than an omnivorous diet; and 
(5) feet with tiny papillae on the underside, which increase traction 
on ice (Stirling 1988, p. 24). Additional adaptations include large, 
paddle-like feet (Stirling 1988, p. 24), and claws that are shorter

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and more strongly curved than those of brown bears, and larger and 
heavier than those of black bears (Ursus americanus) (Amstrup 2003, p. 
589).
Distribution and Habitat
    Polar bears are distributed throughout the ice-covered waters of 
the circumpolar Arctic (Stirling 1988, p. 61), and rely on sea ice as 
their primary habitat (Lentfer 1972, p. 169; Stirling and Lunn 1997, 
pp. 169-170; Amstrup 2003, p. 587). The distribution and movements of 
polar bears in the United States are closely tied to the seasonal 
dynamics of sea ice extent as it retreats northward during summer melt 
and advances southward during autumn freeze. The southern Beaufort Sea 
population occurs south of Banks Island and east of the Baille Islands, 
Canada, and ranges west to Point Hope, Alaska, and includes the 
coastline of Northern Alaska and Canada up to approximately 40 km (25 
mi) inland (Figure 1). The Chukchi and Bering Seas population is widely 
distributed on the sea ice in the Chukchi Sea and northern Bering Sea 
and adjacent coastal areas in Alaska and Russia. The eastern boundary 
of the Chukchi and Bering Seas population is near Colville Delta 
(Arthur et al. 1996, p. 219; Amstrup et al. 2004a, p. 254), and the 
western boundary is near Chauniskaya Bay in the Eastern Siberian Sea. 
The boundary between the Eastern Siberian Sea population and the 
Chukchi and Bering Seas population was determined from movements of 
adult female polar bears captured in the Bering and Chukchi Seas region 
(Garner et al. 1990, p. 222) (Figure 1). The Chukchi and Bering Seas 
population extends into the Bering Sea, and its southern boundary is 
determined by the annual extent of pack ice (Garner et al. 1990, p. 
224; Garner et al. 1994, p. 113; Amstrup et al. 2004a, p. 670). 
Historically polar bears have ranged as far south as St. Matthew Island 
(Hanna 1920, pp. 121-122) and the Pribilof Islands (Ray 1971, p. 13) in 
the Bering Sea. Adult female polar bears captured in the Beaufort Sea 
may make seasonal movements into the Chukchi Sea in an area of overlap 
located between Point Hope and Colville Delta, centered near Point Lay 
(Amstrup et al. 2002, p. 114; Amstrup et al. 2005, p. 254). 
Distributions based on satellite radio-telemetry data show zones of 
overlap between the Chukchi and Bering Seas population and the southern 
Beaufort Sea population (Amstrup et al. 2004a, p. 670; Amstrup et al. 
2005, p. 253). Telemetry data indicate that polar bears marked in the 
Beaufort Sea spend about 25 percent of their time in the northeastern 
Chukchi Sea, whereas females captured in the Chukchi Sea spend only 6 
percent of their time in the Beaufort Sea (Amstrup 1995, pp. 72-73). 
Average activity areas of females in the Chukchi and Bering Seas 
population (244,463 km\2\, range 144,659-351,369 km\2\ (94,387 mi\2\, 
range 55,852-135,664 mi\2\)) (Garner et al. 1990, p. 222) were more 
extensive than those in the Beaufort Sea population (166,694 km\2\, 
range 14,440-616,800 km\2\ (64,360 mi\2\, range 21,564-52,380 mi\2\)) 
(Amstrup et al. 2000b, p. 960). Radio-collared adult females of the 
Chukchi and Bering Seas population (n = 20) spent 68 percent of their 
time in the Russian region and 32 percent in the American region 
(Garner et al. 1990, p. 224).

Sea-Ice Habitat

    Polar bears depend on sea ice for a number of purposes, including 
as a platform from which to hunt and feed upon seals; as habitat on 
which to seek mates and breed; as a platform on which to travel to 
terrestrial maternity denning areas, and sometimes for maternity 
denning; and as a substrate on which to make long-distance movements 
(Stirling and Derocher 1993, p. 241). Mauritzen et al. (2003b, p. 123) 
indicated that habitat use by polar bears during certain seasons may 
involve a trade-off between selecting habitats with abundant prey 
availability versus the use of safer retreat habitats of higher ice 
concentrations with less prey. Their findings indicate that polar bear 
distribution may not be solely a reflection of prey availability, but 
that other factors such as energetic costs or risk may be involved.
    Polar bears show a preference for certain sea-ice stages, 
concentrations, deformation, and forms (Stirling et al. 1993, pp. 18-
22; Arthur et al. 1996, p. 223; Ferguson et al. 2000b, pp. 770-771; 
Mauritzen et al. 2001, p. 1,711; Durner et al. 2004, pp. 16-20; Durner 
et al. 2009a, pp. 51-53). Using visual observations of bears or bear 
tracks, Stirling et al. (1993, p. 15) defined seven types of sea-ice 
habitat and determined habitat preferences. They suggested that the 
following are features that influenced polar bear distribution: (1) 
Stable shore-fast ice with drifts; (2) stable shore-fast ice without 
drifts; (3) floe edge ice; (4) moving ice; (5) continuous stable 
pressure ridges; (6) coastal low level pressure ridges; and (7) fiords 
and bays. Polar bears preferred the floe ice edge, stable shore-fast 
ice with drifts, and moving ice (Stirling 1990 p. 226; Stirling et al. 
1993, p. 18). In another assessment, categories of sea-ice habitat 
included pack ice, shore-fast ice, transition zone (also known as the 
shear zone - the active area consisting of openings between the shore-
fast ice and drifting pack ice), polynyas, and leads (USFWS 1995, p. 
9).
    Pack ice is the primary summer habitat for polar bears in the 
United States (Durner et al. 2004, pp. 16-20). Shore-fast ice is used 
by polar bears for feeding on seal pups, for movement, and occasionally 
for maternity denning (Stirling et al. 1993, p. 20). In protected bays 
and lagoons, the shore-fast ice typically forms in the fall and remains 
stationary throughout the winter. Along the open-shorelines, the shore-
fast ice consists of sea ice that freezes and eventually becomes 
grounded to the bottom, or develops from offshore ice that is pushed 
against the land by the wind and ocean currents (Lentfer 1972, p. 165). 
The shore-fast ice usually occurs in a narrow belt along the coast. 
Most shore-fast ice melts in the summer.
    Open water at leads and polynyas attracts seals and other marine 
mammals and provides preferred hunting habitats during winter and 
spring. The shore system of leads and recurrent polynyas are productive 
areas and are kept at least partially open during the winter and spring 
by ocean currents and winds. The width of the leads ranges from several 
meters to tens of kilometers (Stirling et al. 1993, p. 17).
    Polar bears must move throughout the year to adjust to the changing 
distribution of sea ice and seals (Stirling 1988, p. 63; USFWS 1995, p. 
4). Although polar bears are generally limited to areas where the sea 
is ice-covered for much of the year, they are not evenly distributed 
throughout their range on sea ice. They show a preference for certain 
sea-ice stages and concentrations, and for specific sea-ice features 
(Stirling et al. 1993, pp. 18-22; Arthur et al. 1996, p. 223; Ferguson 
et al. 2000a, p. 1,125; Ferguson et al. 2000b, pp. 770-771; Mauritzen 
et al. 2001, p. 1,711; Durner et al. 2004, pp. 18-19; Durner et al. 
2006a, pp. 34-35; Durner et al. 2009a, pp. 51-53). Sea-ice habitat 
quality varies temporally as well as geographically (Ferguson et al. 
1997, p. 1,592; Ferguson et al. 1998, pp. 1,088-1,089; Ferguson et al. 
2000a, p. 1,124; Ferguson et al. 2000b, pp. 770-771; Amstrup et al. 
2000b, p. 962). Polar bears show a preference for sea ice located over 
and near the continental shelf (Derocher et al. 2004, p. 164; Durner et 
al. 2004, pp. 18-19; Durner et al. 2009a, p. 55). This is likely due to 
higher biological productivity in these areas (Dunton et al. 2005, pp. 
3,467-3,468), and greater accessibility to prey in nearshore shear 
zones and polynyas compared to deep-water regions in the central polar 
basin (Stirling 1997, pp. 12-14). Bears are most abundant near

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the shore in shallow-water areas, and also in other areas where 
currents and ocean upwelling increase marine productivity and serve to 
keep the ice cover from becoming too consolidated in winter (Stirling 
and Smith 1975, p. 132; Stirling et al. 1981, p. 49; Amstrup and 
DeMaster 1988, p. 44; Stirling 1990, pp. 226-227; Stirling and 
[Oslash]ritsland 1995, p. 2,607; Amstrup et al. 2000b, p. 960). Durner 
et al. (2004, pp. 18-19; Durner et al. 2009a, pp. 51-52) found that 
polar bears in the Arctic Basin prefer sea ice concentrations (percent 
of ocean surface area covered by ice) greater than 50 percent, and 
located over continental shelf water, which in Alaska is at depths of 
300 m (984.2 ft) or less.
    Over most of their range, polar bears remain on the sea ice year-
round or spend only short periods on land. In the Chukchi Sea and 
Beaufort Sea areas of Alaska and northwestern Canada, for example, less 
than 10 percent of the polar bear locations obtained via radio 
telemetry were on land (Amstrup 2000, p. 137; Amstrup, USGS, 
unpublished data); the majority of land locations were of polar bears 
occupying maternal dens during the winter. However, some polar bear 
populations occur in seasonally ice-free environments and use land 
habitats for varying portions of the year.
    Polar bear distribution in most areas varies seasonally with the 
extent of sea-ice cover and availability of prey (Stirling and Lunn 
1997, p. 178). The seasonal movement patterns of polar bears emphasize 
the role of sea ice in their life cycle. During the winter in Alaska, 
sea ice may extend 400 kilometers km (248 mi) south of the Bering 
Strait, and polar bears will extend their range to the southernmost 
proximity of the ice (Ray 1971, p. 13). Sea ice disappears from the 
Bering Sea and is greatly reduced in the Chukchi Sea in the summer, and 
polar bears occupying these areas move as much as 1,000 km (621 mi) to 
stay with the retreating pack ice (Garner et al. 1990, p. 222; Garner 
et al. 1994, pp. 407-408). Throughout the Polar Basin during the 
summer, polar bears generally concentrate along the edge of or into the 
adjacent persistent pack ice (Durner et al. 2004; Durner et al. 2006a). 
Major northerly and southerly movements of polar bears appear to depend 
on distribution of sea ice delimited by the seasonal melting and 
refreezing of sea ice (Amstrup 2000, p. 142).
    In areas where sea-ice cover and character are seasonally dynamic, 
a large multi-year home range, of which only a portion may be used in 
any one season or year, is an important part of the polar bear life 
history strategy. In other regions, where ice is less dynamic, home 
ranges are smaller and less variable (Ferguson et al. 2001, pp. 51-52). 
Data from telemetry studies of adult female polar bears show that they 
do not wander aimlessly on the ice, nor are they carried passively with 
the ocean currents as previously thought (Pedersen 1945 cited in 
Amstrup 2003, p. 587; Amstrup et al. 2000b, p. 956; Mauritzen et al. 
2001, p. 1704, Mauritzen et al. 2003a, p. 111; Mauritzen et al. 2003b, 
p. 123). Results show strong fidelity to activity areas that are used 
over multiple years (Ferguson et al. 1997, p. 1,589). Not all 
geographic areas within an individual polar bear's home range are used 
each year. The distribution patterns of some polar bear populations 
during the open water and early fall seasons have changed in recent 
years (Durner et al. 2006, p. 30; Durner et al. 2009a, pp. 49, 53). In 
the Beaufort Sea, for example, greater numbers of polar bears are being 
found on shore during the fall than recorded at any previous time 
(Schliebe et al. 2006, p. 559).

Terrestrial Denning Habitat

    Unlike brown bears and black bears, which hibernate in winter when 
food is unavailable, polar bears are able to forage for seals 
throughout the winter (Amstrup 2003, p. 593). Generally, only pregnant 
polar bears routinely enter dens in the fall for extended periods 
(however, see Messier et al. 1994 and Ferguson et al. 2000a). 
Typically, pregnant female polar bears go into the dens in November, 
give birth in late December, and emerge from their dens after the cubs 
have reached 9.1-11.4 kg (20-25 lbs) in March and April (Ramsay and 
Stirling 1988, p. 602). In Alaska, cubs stay with their mother for 2 
years after departing the den (Amstrup 2003, p. 599).
    Polar bears are particularly vulnerable to anthropogenic and 
natural disturbances during denning compared to other times in their 
life cycle (Amstrup 2003, p. 606) because they are more limited in 
their ability to safely move away from the disturbance. The cubs, which 
are born in mid-winter, weigh only 600-700g (1.3-1.5 lbs), are blind, 
lightly furred, and helpless (Blix and Lentfer 1979, p. R67). The 
maternal den provides a relatively warm, protected, and stable 
environment until they are large enough (approximately 11.4 kg (25 
lbs)) to survive conditions outside the den in March or April. The dens 
provide thermal insulation, and if the family group abandons the den 
early, the cubs will die (Blix and Lentfer 1979, p. R67; Amstrup and 
Gardner 1994, p. 7). Throughout the species' range, most pregnant 
female polar bears excavate dens in snow located on land in the fall 
and early winter period (Harington 1968, p. 6; Lentfer and Hensel 1980, 
p. 102; Ramsay and Stirling 1990, p. 233; Amstrup and Gardner 1994, p. 
5). The only known exceptions are in western and southern Hudson Bay, 
where polar bears first excavate earthen dens and later reposition into 
adjacent snow drifts (Jonkel et al. 1972, p. 146; Ramsay and Stirling 
1990, p. 233), and in the southern Beaufort Sea, where a portion of the 
population dens in snow caves located on the drifting pack ice and 
shore-fast ice (Amstrup and Gardner 1994, p. 5). Successful denning by 
polar bears requires accumulation of sufficient snow for den 
construction and maintenance and insulation for the female and cubs. 
Adequate and timely snowfall combined with winds that cause snow 
accumulation leeward of requisite topographic features create denning 
habitat (Harington 1968, p. 12). In addition, for bears moving from the 
sea ice to land, the timing of freeze-up and the distance from the pack 
ice are two factors that can affect when pregnant females enter dens.
    A great amount of polar bear denning arctic-wide occurs in core 
areas, which show high use over time (Harington 1968, pp. 7-8). 
Examples include the west coast of Hudson Bay in Canada and Wrangel 
Island in Russia (Harrington 1968, p. 8; Ramsey and Stirling 1990, p. 
233). In some portions of the species' range, polar bear dens are more 
dispersed, with dens scattered over larger areas at lower density 
(Lentfer and Hensel 1980, p. 102; Stirling and Andriashek 1992, p. 363; 
Amstrup 1993, p. 247; Amstrup and Gardner 1994, p. 5; Messier et al. 
1994, p. 425; Born 1995, p. 84; Ferguson et al. 2000a, p. 1125; Durner 
et al. 2001, p. 117; Durner et al. 2003, p. 57). In northern Alaska, 
while denning habitat is more diffuse than in other areas, certain 
areas such as barrier islands, river banks, much of the North Slope 
coastal plain, and coastal bluffs that occur at the interface of 
mainland and marine habitat receive proportionally greater use for 
denning (Durner et al. 2004, entire; Durner et al. 2006a, entire).
    The primary denning habitat for polar bears in the southern 
Beaufort Sea population is on the relatively flat topography of the 
coastal area on the North Slope of Alaska and the pack ice (Amstrup 
1993, p. 247; Amstrup and Gardner 1994, p. 7; Durner et al. 2001, p. 
119; Durner et al. 2003, p. 61; Fischbach et al. 2007, p. 1,400). Some 
of the habitat suitable for the accumulation

[[Page 56064]]

of snow and use for denning has been mapped on the North Slope (Durner 
et al. 2001, entire; Durner et al. 2006a, entire). The primary denning 
areas for the Chukchi and Bering Seas population occur on Wrangel 
Island, Russia, where up to 200 bears per year have denned annually, 
and the northeastern coast of the Chukotka Peninsula, Russia (Stishov 
1991a, p. 107; Stishov 1991b, p. 91; Ovsyanikov 2006, p.169). The key 
characteristic of all denning habitat is topographic features that 
catch snow in the autumn and early winter (Durner et al. 2003, p. 61). 
As in the Canadian arctic, Russia, and Svalbard, Norway (Harington 
1968, p. 12; Larsen 1985, p. 322; Stishov 1991b, p. 91; Stirling and 
Andriashek 1992, p. 364), most polar bear dens in Alaska occur 
relatively near the coast along the coastal bluffs and river banks of 
the mainland and barrier islands and on the drifting pack ice (Amstrup 
and Gardner 1994, p. 5; Amstrup 2003, p. 596).
Previous Federal Actions
    We listed polar bears as a threatened species under the Act on May 
15, 2008 (73 FR 28212). At the time of listing, we determined that 
critical habitat for the polar bear was prudent, but not determinable. 
We concluded that given the complexity of determining which specific 
areas in the United States might contain physical and biological 
features essential to the conservation of the polar bear under rapidly 
changing environmental conditions, we required additional time to 
conduct a thorough evaluation and coordinate with species experts. 
Thus, we did not propose critical habitat for the polar bear at that 
time. The Service then issued a special rule for the polar bear under 
section 4(d) of the Act on December 16, 2008 (73 FR 76249). The special 
rule provides measures that are necessary and advisable to provide for 
the conservation of the polar bear.
    On July 16, 2008, the Center for Biological Diversity, Natural 
Resources Defense Council, and, Greenpeace, Inc., filed an amended 
complaint against the Service for, in part, failing to designate 
critical habitat for the polar bear concurrently with the final listing 
rule [Center for Biological Diversity et al. v. Kempthorne et al., No. 
08-2113- D.D.C. (transferred from N.D. Cal.)]. On October 7, 2008, the 
U.S. District Court for the Northern District of California entered an 
order approving a stipulated settlement of the parties. The stipulated 
settlement, in part, requires the Service, on or before June 30, 2010, 
to submit to the Federal Register a final critical habitat 
determination for the polar bear. Comments or information that we 
receive in response to this proposed rule will allow us to comply with 
the court order and section 4(b)(2) of the Act. For more information on 
previous Federal actions concerning the polar bear, refer to the final 
listing rule and final special rule published in the Federal Register 
on May 15, 2008 (73 FR 28212), and December 16, 2008 (73 FR 76249), 
respectively.

Critical Habitat

    Critical habitat is defined in section 3 of the Act as:
    (1) The specific areas within the geographical area occupied by a 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features
    (a) essential to the conservation of the species and
    (b) which may require special management considerations or 
protection; and
    (2) specific areas outside the geographical area occupied by a 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Conservation, as defined under section 3 of the Act, means the use 
of all methods and procedures that are necessary to bring any 
endangered species or threatened species to the point at which the 
measures provided under the Act are no longer necessary.
    Critical habitat receives protection under section 7 of the Act 
through the prohibition against Federal agencies carrying out, funding, 
or authorizing the destruction or adverse modification of critical 
habitat. Section 7 of the Act requires consultation on Federal actions 
that may affect critical habitat. The designation of critical habitat 
does not affect land ownership or establish a refuge, wilderness, 
reserve, preserve, or other conservation area, nor does it allow the 
government or public to access private lands. Such designation does not 
require implementation of restoration, recovery, or enhancement 
measures by the landowner. Where the landowner seeks or requests 
Federal agency funding or authorization that may affect a listed 
species or critical habitat, the consultation requirements of section 7 
of the Act would apply. However, even in the event of destruction or an 
adverse modification finding, the landowner's obligation is not to 
restore or recover the species, but to implement reasonable and prudent 
alternatives to avoid destruction or adverse modification of critical 
habitat.
    For inclusion in a critical habitat designation, habitat within the 
geographical area occupied by the species at the time it was listed 
must contain the physical and biological features essential to the 
conservation of the species. Critical habitat designations identify, to 
the extent known using the best scientific data available, habitat 
areas that provide essential life cycle needs of the species (areas on 
which are found the primary constituent elements, as defined at 50 CFR 
424.12(b)). Occupied habitat that contains the features essential to 
the conservation of the species meets the definition of critical 
habitat only if those features may require special management 
considerations or protection. Under the Act, we can designate 
unoccupied areas as critical habitat only when we determine that the 
best available scientific data demonstrate that the designation of that 
area is essential to the conservation needs of the species.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific data available. Further, our Policy on 
Information Standards under the Endangered Species Act (published in 
the Federal Register on July 1, 1994 (59 FR 34271)), the Information 
Quality Act (section 515 of the Treasury and General Government 
Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), 
and our associated Information Quality Guidelines provide criteria, 
establish procedures, and provide guidance to ensure that our decisions 
are based on the best scientific data available. They require our 
biologists, to the extent consistent with the Act and with the use of 
the best scientific data available, to use primary and original sources 
of information as the basis for recommendations to designate critical 
habitat.
    When we are determining which areas should be proposed as critical 
habitat, our primary source of information is generally the information 
developed during the listing process for the species. Additional 
information sources may include articles in peer-reviewed journals, 
conservation plans developed by States and counties, scientific status 
surveys and studies, biological assessments, or other unpublished 
materials and expert opinion.
    Habitat is often dynamic, and species may move from one area to 
another over time. Furthermore, we recognize that this critical habitat 
determination may not include all of the habitat areas that we may 
eventually determine, based on scientific data not now available to the 
Service, are necessary for the recovery of the species. For these 
reasons, a critical habitat designation does not signal that habitat 
outside the designated area is unimportant or may

[[Page 56065]]

not be required for the conservation or survival of the species.
    Areas that support polar bear populations in the United States, but 
are outside the critical habitat designation, will continue to be 
subject to conservation actions we implement under section 7(a)(1) of 
the Act and our other wildlife authorities. They are also subject to 
the regulatory protections afforded by the section 7(a)(2) jeopardy 
standard, as determined on the basis of the best available scientific 
information at the time of the agency action. Federally funded or 
permitted projects affecting listed species outside their designated 
critical habitat areas may result in jeopardy findings in some cases. 
Similarly, critical habitat designations made on the basis of the best 
available information at the time of designation will not control the 
direction and substance of future recovery plans, habitat conservation 
plans (HCP), or other species conservation planning efforts if new 
information available to these planning efforts calls for a different 
outcome.
Methods
    As required by section 4(b) of the Act, we used the best scientific 
data available to determine the specific geographical areas occupied at 
the time of listing that contain features essential to the conservation 
of the polar bear in the United States that may require special 
management or protection, and specific areas outside the geographical 
area occupied by the polar bear at the time of listing that are 
essential to the conservation of the polar bears in the United States. 
In proposing critical habitat for polar bears in the United States, we 
reviewed the relevant information available, including peer-reviewed 
journal articles, the final listing rule, and unpublished reports and 
materials (such as survey results and expert opinions). In general, 
polar bears occupy the vast majority of their historic range. 
Exceptions include St. Matthew Island (Hanna 1920, pp. 121-122) and the 
Pribilof Islands (Ray 1971, p. 13) in the Bering Sea. As described in 
detail below, we have proposed to designate as critical habitat only 
those areas currently occupied by the polar bear and have determined 
that designating only occupied areas as critical habitat for polar 
bears is sufficient for the conservation of the species in the United 
States. As such, we are not proposing to designate as critical habitat 
any areas outside the geographical area occupied by polar bears in the 
United States.
    While the amount of information regarding important polar bear life 
functions and habitats associated with these functions has expanded 
greatly in Alaska during the past 20 years, the identification of 
specific physical and biological features essential to the conservation 
of the polar bear is complex. (see the polar bear final listing rule 
(May 15, 2008 (73 FR 28212) for a review of polar bear biology, 
ecology, and threats). Moreover, the future values of these essential 
features to the conservation of the species may change in a rapidly 
changing environment. Most notably, arctic sea ice provides a platform 
for critical life-history functions, including hunting, feeding, 
travel, and nurturing cubs. Sea ice is projected to be significantly 
reduced within the next 45 years, and some predictive climate models 
project complete absence of sea ice during summer months in shorter 
timeframes (Amstrup et al. 2008, p. 239; Durner et al. 2009a, p. 45). 
(see the polar bear final listing rule (May 15, 2008 (73 FR 28212)) for 
a more detailed discussion of climate change in the Arctic and the 
threat of this change to polar bears).
Primary Constituent Elements
    In accordance with section 3(5)(A)(i) of the Act and the 
regulations at 50 CFR 424.12, in determining which specific 
geographical areas occupied at the time of listing to propose as 
critical habitat, we considered areas containing the physical and 
biological features essential to the conservation of the species which 
may require special management considerations or protection. These 
features include, but are not limited to:
    (1) Space for individual and population growth and for normal 
behavior;
    (2) Food, water, air, light, minerals, or other nutritional or 
physiological requirements;
    (3) Cover or shelter;
    (4) Sites for breeding, reproduction, or rearing (or development) 
of offspring; and
    (5) Habitats that are protected from disturbance or are 
representative of the historic, geographical, and ecological 
distributions of a species.
    We derive the specific primary constituent elements (PCEs) for the 
polar bear in the United States based on its physical and biological 
needs, as described in the Background section of this proposed rule and 
the following information.

Space for Individual and Population Growth and for Normal Behavior

    Although home ranges can vary greatly among individuals (Garner et 
al. 1990, p. 224; Amstrup et al. 2000b, p. 956), the overall home range 
size for polar bears from the two U.S. populations is relatively large. 
The movement patterns and home ranges of polar bears are directly 
related to the seasonal, highly dynamic, redistributions of sea ice 
(Garner et al. 1990, p. 224; Garner et al. 1994, pp. 112-113; Ferguson 
et al. 2001, pp. 51-52; Mauritzen et al. 2001, p. 1709; Durner et al. 
2004, pp. 16-20; Durner et al. 2006a, pp. 27-30). The movement patterns 
of the sea ice strongly influence the availability and accessibility of 
the preferred prey for polar bears, ringed and bearded seals (Stirling 
et al. 1993, p. 21).
    Polar bears require sea ice as a platform for hunting and feeding 
on seals, seasonal and long-distance movements, travel to terrestrial 
maternal denning areas, resting, and mating (Stirling and Derocher 
1993, p. 241). Moore and Huntington (2009, p. S159) classified polar 
bears as an ice-obligate (ice restricted) species due to this 
dependence on sea ice as a platform for resting, breeding, and 
foraging. A majority of the polar bears in the U.S. populations remain 
with the sea ice year-round and prefer the annual sea ice located over 
the continental shelf, and areas near the southern ice edge, for 
foraging (Laidre et al. 2008, p. S105; Durner et al. 2009a, p. 39). 
Open water is not considered an essential feature for polar bears, 
because life functions such as feeding, reproduction, or resting do not 
occur in open water. However, open water is a fundamental part of the 
marine system that supports seal species, the principal prey of polar 
bears, and seasonally refreezes to form the ice needed by the bears. 
The interface of open water and sea ice is an important habitat used by 
polar bears (Stirling et al. 1993, pp.18, 20-22; Stirling 1997, pp. 11, 
15, 16; Durner et al. 2009a, p. 52). In addition, the extent of open 
water may play an integral role in the behavior patterns of polar bears 
because vast areas of open water may limit a bear's ability to access 
sea ice or land (Monnett and Gleason 2006, p. 5).
    The optimal sea-ice habitat for polar bears varies both 
geographically and temporally, and the use of this area varies 
seasonally, with the greatest movements occurring during the advance of 
the sea ice in fall and early winter and retreat of the sea ice during 
spring and early summer. The dynamic nature of the sea ice in the 
Beaufort and Chukchi Seas, which changes continually within and among 
years, makes it difficult to predict the specific time or area where 
the optimal habitat occurs. However, the Resource Selection Function 
(RSF) models (Durner et al.

[[Page 56066]]

2004, pp. 16-19; Durner et al. 2006a, pp. 26-29; Durner et al. 2009a, 
p. 39) show that polar bears will select areas of sea-ice habitat with 
the following characteristics: sea ice concentrations approximately 50 
percent or greater that are adjacent to open water areas, flaw zones, 
leads, and polynyas, and that are over the shallower, more productive 
waters over the continental shelf (waters 300 m (984.2 ft) or less in 
depth).
    Information on the seasonal movements of polar bears suggests that 
they select for ice conditions that maximize their foraging 
opportunities. Water depth, sea ice concentration (as described below), 
and proximity to the ice edge, where flaw zones, polynyas, leads, or 
open water occur, appear to be the important characteristics of the 
preferred polar bear feeding and movement habitat (Durner et al. 2004, 
p. 16). Preferred polar bear foraging habitat occurs primarily on the 
annual sea ice over the shallower (300 m (984.2 ft) or less) waters of 
the continental shelf (Durner et al. 2004a, p. 19; Durner et al. 2009a, 
p. 52). This is consistent with the distribution of their preferred 
prey species, ringed and bearded seals, which are also generally found 
over the continental shelf. Stirling et al. (1982, p. 14) found that 
ringed seal densities were greatest in ocean waters at depths between 
50-100 m (164-328 ft) and with greater than 80 percent ice cover, 
whereas bearded seals were generally found in shallower waters (25-50 m 
(82-164 ft) deep) with relatively low ice cover.
    Mauritzen et al. (2003b, p. 123) suggested that polar bears select 
habitat with sea ice concentrations that are optimal for hunting seals, 
provide safety from ocean storms, and prevent them from becoming 
separated from the main pack ice. Polar bears are most often found 
where sea ice concentrations exceed 50 percent (Stirling et al. 1999, 
p. 295; Durner et al. 2004, pp. 18-19; Durner et al. 2006a, p. 24; 
Durner et al. 2009a, p. 51). However, they will use lower sea ice 
concentrations if this is the only ice that is available over the 
shallower, more productive waters of the continental shelf. This was 
evident during the late-summer to early-fall open water period in 
August and September of 2008. During this time, most of the sea ice in 
the Beaufort Sea had receded beyond the edge of the continental shelf, 
except for a narrow tongue of sparse ice that extended over shelf 
waters in the eastern Beaufort Sea. Polar bears were documented using 
this marginal sea-ice habitat with sea ice concentrations between 15 
percent and 30 percent, presumably in an attempt to remain in the more 
productive feeding areas over the continental shelf (Steve Amstrup, 
U.S. Geological Survey, pers. comm.; USFWS, unpublished data).
    Ice in proximity to the ice edge (near open water), polynyas, or 
leads provide polar bears access to ringed and bearded seals. In 
winter, polar bears select areas of high sea-ice concentrations along 
the Alaska coast (Durner et al. 2009a, p. 52), with their preferred 
habitat being sea-ice habitat near the flaw zones, polynyas, and shore 
leads that run parallel to the mainland coast of Alaska. During other 
times of the year, the marginal sea ice zone near the sea ice edge is 
the optimal feeding habitat for polar bears because access and 
availability of ringed seals is greatest in this zone (Durner et al. 
2004, pp. 18-19). This is presumably because seals are available and 
accessible in the adjacent flaw zones and polynyas (USFWS 1995, p. 14; 
Stirling 1997, p. 14) that are in the shallower, more productive waters 
over the continental shelf.
    Reductions in sea ice negatively impact polar bears by increasing 
the energetic demands of movement in seeking prey, causing seasonal 
redistribution of substantial portions of polar bear populations into 
marginal ice or terrestrial habitats with fewer opportunities for 
feeding, and increasing the susceptibility of bears to other stressors. 
As the summer sea ice edge retracts to deeper, less productive Polar 
Basin waters, polar bears will face increasing competition for limited 
food resources, increasing distances to swim with increased risk of 
drowning, increasing interaction with humans in terrestrial or 
nearshore areas with negative consequences, and declining population 
(Amstrup et al. 2008).
    Reductions in sea ice will likely reduce productivity of most ice 
seal species as well, result in changes in composition of seal species 
indigenous to some areas, and eventually result in a decrease in seal 
abundance (Derocher et al. 2004. pp. 167-169). These changes will 
likely decrease availability, or the timing of availability, of seals 
as food for polar bears. Ringed seals will likely remain distributed in 
shallower, more productive southerly areas that are losing their 
seasonal sea ice and becoming characterized by vast expanses of open 
water in the spring--summer and fall periods (Harwood and Stirling 
1992, pp. 897-898). As a result, the seals will remain unavailable as 
prey to polar bears during critical times of the year. These factors 
may, in turn, result in a steady decline in the physical condition of 
polar bears, which precedes population-level demographic declines in 
reproduction and survival (Stirling and Parkinson 2006, pp. 266-267; 
Regehr et al. 2007a, pp. 2679-2681).
    One of the expected outcomes from climate change in the Arctic is 
that the distance between the southern edge of the pack ice and coastal 
denning areas will increase during the summer. This is likely to result 
in an increase in use of terrestrial areas during the summer and early 
fall (Schliebe et al. 2008, p. 2). Should the distance become too 
great, it could reduce polar bears' access to, and hence the 
availability of, optimal feeding habitat and preferred terrestrial 
denning locations during critical times of the year (Bergen et al. 
2007, p. 6).
    Based on the best information available, the dynamic nature of sea-
ice habitat in the Arctic, and the preference of polar bears for sea-
ice habitat located over the continental shelf, we have determined that 
sea ice over the shallower waters of the continental shelf (waters of 
300 m or less (984.2 ft or less)) is an essential physical feature for 
polar bears in the southern Beaufort and Chukchi and Bering Seas for 
feeding, rearing of offspring, and normal behavior, i.e., space for 
individual and population growth and for normal behavior.

Food, Water, Air, Light, Minerals, or Other Nutritional or 
Physiological Requirements

    Polar bears are carnivores that feed primarily on ice-dependent 
seals (frequently referred to as ``ice seals'') throughout their range. 
Their main species of prey is the ringed seal; polar bears also hunt, 
to a lesser extent, bearded seals (Stirling and Archibald 1977, p. 
1,127; Smith 1980, p. 2, 201). In some locales, other seal species are 
taken. On average, an adult polar bear needs approximately 2 kg (4.4 
lbs) of seal fat per day to survive (Best 1985, p. 1,035). Sufficient 
nutrition is critical for survival in the arctic environment and may be 
obtained and stored as fat when prey is abundant.
    Although seals are their primary prey, polar bears occasionally 
take much larger animals, such as walruses (Odobenus rosmarus), narwhal 
(Monodon monoceros), and beluga whales (Delphinapterus leucas) (Kiliaan 
and Stirling 1978, p. 199; Smith 1980, p. 2,206; Smith 1985, pp. 72-73; 
Lowry et al. 1987, p. 141; Calvert and Stirling 1990, p. 352; Smith and 
Sjare 1990, p. 99). In some areas and under some conditions, prey other 
than seals, such as carrion or remains of subsistence harvested bowhead 
whales, may be important to polar bear sustenance as short-term 
supplemental forms of nutrition. Stirling and [Oslash]ritsland (1995, 
p. 2,609) suggested that in areas where

[[Page 56067]]

ringed seal populations were reduced, other prey species were being 
substituted. For example, harp seals (Pagophilus groenlandicus) are the 
predominant prey species for polar bears from the Davis Strait 
population in Canada (Iverson et al. 2006, p. 110). Changes in the 
distribution of harp seals may continue to support large numbers of 
polar bears from the Davis Strait population even if ringed seals 
become less available (Stirling and Parkinson 2006, p. 270; Iverson et 
al. 2006, p. 110). However, the increased take of other species, such 
as bearded seals, walrus, and harbor seals, in the United States, if 
those species were available, would likely not compensate for reduced 
availability of ringed seals (Derocher et al. 2004, p. 168).
    Polar bears are very sensitive to changes in sea ice due to climate 
change because of their reliance on sea ice and their specialized 
feeding requirements (Laidre et al. 2008, p. S112). The importance of 
availability of prey to polar bear reproduction was evident in the mid-
1970s when a decline in ringed and bearded seals resulted in a decline 
in the weights of adult female polar bears and a decline in 
reproduction (Stirling et al. 1982, p. 19; Amstrup et al. 1986, p. 
249). Changes in the distribution and abundance of optimal sea ice 
feeding habitat due to climate change could also affect polar bear 
denning success. For example, the availability and accessibility of 
seals to polar bears, which often hunt at the seals' breathing hole, 
are likely to decrease with increasing amounts of open water or 
fragmented ice (Derocher et al. 2004, p. 167). Pregnant polar bear 
females with insufficient fat stores prior to denning, or in poor 
hunting condition in the early spring after den emergence, may lead to 
increased cub mortality (Atkinson and Ramsay 1995, pp. 565-566; 
Derocher et al. 2004, p. 170). Regehr et al. (2007b, pp. 17-18) 
suggested that the increase in the duration of the open water period in 
fall was a contributing factor to the decrease in the productivity of 
polar bears in the southern Beaufort Sea population and to the 
population decline in the Western Hudson Bay population (Stirling et 
al. 1999, p. 304; Regehr et al. 2007a, p. 2,673). In the southern 
Beaufort Sea, the decline in the survival rate of cubs may be directly 
linked to the ability of females to obtain sufficient nutrition prior 
to denning (Regehr et al. 2006, p. 11, Amstrup et al. 2008, p. 236). 
The inability to obtain sufficient food resources may be due to 
increases in the length of the fall open water period, which reduces 
the amount of time available for feeding prior to denning. Polar bears 
in the southern Beaufort Sea typically reach their maximum weight in 
fall. Fall, therefore, may be a critical period for winter survival for 
this population (Garner et al. 1994, p. 117; Durner and Amstrup 1996, 
p. 483). In Alaska, it is not unusual for females in poor condition 
after den emergence to lose their cubs (Amstrup 2003, p. 601). Thus, 
the availability of seal pups to adult females with cubs-of-the-year in 
the spring following den emergence may also be critical (Garner et al. 
1994, p. 117; Stirling and Lunn 1997, p. 177). Atkinson and Ramsay 
(1995, p. 565), and Derocher and Stirling (1996, p. 1,249; 1998, pp. 
255-256), found that heavier cubs have a higher survival rate, and that 
declines in fat reserves in females during critical periods can 
negatively affect denning success and cub survival.
    Based on the information presented above, we conclude that the 
accessibility and availability of sufficient food resources is 
dependent upon availability of suitable sea-ice habitat over the 
shallower waters of the Chukchi and Bering Seas and southern Beaufort 
Sea. Therefore, we have determined that sea ice that moves over the 
shallower waters of the continental shelf (300 m (984.2 ft) or less) is 
an essential physical feature for polar bears in the southern Beaufort 
and Chukchi and Bering Seas for feeding, rearing of offspring, and 
normal behavior.

Cover or Shelter

    Polar bears from the U.S. populations generally remain with the sea 
ice for most of the year, and, except for maternal denning, only spend 
short periods of time on land. This may be due to the availability of 
the sea ice year-round and less severe weather conditions compared to 
more northerly latitudes. Polar bears from U.S. populations take 
advantage of logs, ocean bluffs, and stream and river drainages to seek 
shelter from the wind (Lentfer 1976, p. 9). Messier et al. (1994, p. 
425), Ferguson et al. (2000a, p. 1,122) and Omi et al. (2003, p. 195) 
found that polar bears of all ages and both sexes from more northerly 
populations in Canada may remain in temporary shelter dens in snow 
drifts on the ice for up to 2 months, presumably to avoid storms, 
periods of intense cold, and food shortages. Occasionally polar bears 
in the United States, particularly females with small cubs, will dig 
temporary shelter dens to avoid severe winter storms (Lentfer 1976, p. 
9; Amstrup, unpublished data). Information from native hunters in 
Alaska suggests that, except for parturient (bearing or about to bear 
young) females and females with young cubs, polar bears do not require 
additional cover or shelter for survival throughout the year (Lentfer 
1976, p. 9). However, the importance of these shelter dens may increase 
in the future if polar bears, experiencing nutritional stress as a 
result of loss of optimal sea-ice habitat and access to prey, need to 
minimize nonessential activities to conserve energy.
    Currently, cover and shelter are no