Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Polar Bear (Ursus maritimus) in the United States, 76086-76137 [2010-29925]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 75, Number 234 (Tuesday, December 7, 2010)]
[Rules and Regulations]
[Pages 76086-76137]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-29925]



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Part II





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



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

Federal Register / Vol. 75 , No. 234 / Tuesday, December 7, 2010 / 
Rules and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. 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: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), 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 484,734 square kilometers (km\2\) 
(187,157 square miles (mi\2\)) fall within the boundaries of the 
critical habitat designation. The critical habitat is located in Alaska 
and adjacent territorial and U.S. waters.

DATES: This rule becomes effective on January 6, 2011.

ADDRESSES: The final rule and final economic analysis are available for 
viewing at https://www.regulations.gov. You can view detailed, colored 
maps of critical habitat areas in this final rule at https://alaska.fws.gov/fisheries/mmm/polarbear/criticalhabitat.htm. Supporting 
documentation used in preparing this final rule is available for public 
inspection, by appointment, during normal business hours, at the U.S. 
Fish and Wildlife Service, Marine Mammals Management Office, 1011 East 
Tudor Road, Anchorage, AK 99503; telephone 907/786-3800; facsimile 907/
78-3816.

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. If you use a 
telecommunications device for the deaf (TDD), call the Federal 
Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION: 

Background

    It is our intent to discuss only those topics directly relevant to 
the designation of the critical habitat for the polar bear in the 
United States in this final rule. For more information on the polar 
bear, refer to the final listing rule published in the Federal Register 
on May 15, 2008 (73 FR 28212), the proposed rule to designate critical 
habitat published in the Federal Register on October 29, 2009 (74 FR 
56058), and the document published on May 5, 2010 (75 FR 24545), that 
made available the draft economic analysis (DEA). Detailed information 
on polar bear biology and ecology 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 U.S. 
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 include in this 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 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 final rule, we are referring to both of 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

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of sea ice strongly influence the distribution and accessibility of 
ringed seals (Pusa 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, 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). 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, entire; 
Durner et al. 2006a, entire). 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: the southern 
Beaufort Sea population, which extends into Canada; and the Chukchi-
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 (Amstrup et al. 2004a, p. 670). The Service listed 
the polar bear as a threatened species throughout its range under the 
Act on May 15, 2008 (73 FR 28212; final rule available at https://alaska.fws.gov/fisheries/mmm/polarbear/issues.htm).
    Figure 1. Approximate bounds (95 percent contour) for the southern 
Beaufort Sea and the Chukchi-Bering Seas polar bear populations based 
on satellite radio-telemetry locations from 1985-2003.

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[GRAPHIC] [TIFF OMITTED] TR07DE10.000

    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 and 
more strongly curved than those of brown bears and that are 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; 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-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-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-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-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

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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-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-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-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, forms, and deformation types (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 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 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, U.S. Geological 
Survey, 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; Garner et al. 1990, p. 222). 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

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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, which, in turn, is determined 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). Polar bears are highly 
evolved with respect to survival during periods of food deprivation. 
During food shortages, they are able to shift their metabolism into a 
hibernation-like pattern, but still remain active. 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 or 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 600-700 g (1.3-1.5 lbs), and 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. Access to terrestrial 
denning sites is dependent upon the location of the sea ice, amount of 
stable ice, ice consolidation, and the length of the melt season during 
the summer and fall (Fischbach et al. 2007, p. 1,395). The Alaskan 
southern Beaufort Sea and the Chukchi-Bering Seas polar bear 
populations typically remain with the sea ice throughout the year. 
During the fall, when the sea ice is at its minimum extent, the 
parturient females begin to look for suitable denning sites in 
relatively close proximity to the sea-ice edge. The closest terrestrial 
denning sites to the ice edge in the Chukchi Sea during the late fall 
are Wrangel Island, Russia, and the northern coastline of the Chukotka 
Peninsula, Russia. Polar bears from the Chukchi-Bering Seas population 
have typically used terrestrial den sites in Russia because 
accessibility to potential terrestrial denning habitat in western 
Alaska is not possible due to the great distance polar bears would have 
to swim. In the future the distance between the Chukchi Sea ice edge 
and western Alaska is expected to increase due to changes in the sea-
ice characteristics (described below in the section Sites for Breeding, 
Reproduction, or Rearing (or Development) of Offspring) from climate 
change.
    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 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-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

[[Page 76091]]

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 the polar bear 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. We issued a final special rule for the polar bear under section 
4(d) of the Act (16 U.S.C. 1531 et seq.) 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, required the Service, on or before June 30, 2010, 
to submit to the Federal Register a final critical habitat 
determination for the polar bear. On March 24, 2010, the U.S. District 
Court for District of Columbia approved the stipulation extending the 
deadline for submission of the final critical habitat designation to 
the Federal Register to November 23, 2010. The Service issued the 
proposed rule for the designation of critical habitat for the polar 
bear in the United States on October 29, 2009 (74 FR 56058). We also 
published a document making available the draft economic analysis of 
the proposed critical habitat designation on May 5, 2010 (75 FR 24545). 
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.

Summary of Comments and Recommendations

    We requested written comments from the public during two comment 
periods on the proposed rule to designate critical habitat for the 
polar bear in the United States. The first comment period, which was 
associated with the publication of the proposed rule (74 FR 56058), 
opened on October 29, 2009. That comment period was open for 60 days, 
closing on December 28, 2009. We also requested comments on the 
proposed critical habitat designation and associated draft economic 
analysis (DEA) during a 60-day comment period that opened May 5, 2010, 
and closed on July 6, 2010 (75 FR 24545). During the comment periods we 
also contacted appropriate Federal, State, and local agencies; Alaska 
Native organizations; and other interested parties and invited them to 
comment on the proposed rule to designate critical habitat for the 
polar bear in Alaska and the associated DEA.
    In response to requests from the public, public hearings were held 
in Anchorage, Alaska on June 15, 2010, and Barrow, Alaska on June 17, 
2010. These hearings were announced in the Federal Register on May 5, 
2010 (75 FR 24545), and a legal notice of the hearings was published in 
the Legal Section of the Anchorage Daily News (June 1, 2010). Three 
display ads announcing the hearings on proposed critical habitat were 
published on June 10, 2010, in the Arctic Sounder (Barrow, Alaska), 
Nome Nugget (Nome, Alaska), and Anchorage Daily News (Anchorage, 
Alaska). A fourth display ad was published in the Anchorage Daily News 
on June 14, 2010. We established teleconferencing capabilities for the 
Barrow, Alaska, public hearing to allow outlying villages the 
opportunity to provide oral testimony. The communities of Kotzebue and 
Little Diomede participated in this public hearing via teleconference. 
The public hearings were attended by approximately 73 people.
    In addition, information on the proposed critical habitat was 
presented at the Inuvialuit Game Council and North Slope Borough 
meeting on April 29, 2009, in Barrow, Alaska; the Alaska Nanuuq 
Commission Meeting on August 25-26, 2009, in Nome, Alaska; and the 
North Slope Borough on March 1, 2010, in Barrow, Alaska.
    During the public comment periods, we received approximately 
111,690 comments, including letters and post cards, citizen petitions, 
e-mail or web messages, and public hearing testimony. We received 
comments from Federal agencies, Alaska Native Tribes and tribal 
organizations, Federal commissions, State and local governments, 
commercial and trade organizations, conservation organizations, non-
governmental organizations, and private citizens.
    A majority of the comments received (99 percent) supported the 
proposed designation of critical habitat for polar bears in Alaska. The 
range of comments varied from those that provided general supporting or 
opposing statements with no additional explanatory information to those 
that provided extensive comments and information supporting or opposing 
the proposed designation. All substantive information provided during 
both comment periods has been considered in this final determination 
and, where appropriate, has been incorporated directly either into this 
final rule or the final economic analysis, or is addressed below.
    Comments on the October 29, 2009, proposed rule (74 FR 56058) and 
subsequently on the DEA varied considerably, from those that questioned 
the need for the critical habitat designation to those that stated the 
proposed critical habitat designation did not provide enough protection 
for the polar bear. Many of the comments focused on the need to include 
or exclude additional habitat from the proposed critical habitat 
designation.
    Some comments suggested that the Service should increase the 
proposed designated critical habitat to include: (1) Areas currently 
unoccupied or marginal, as they may become more important as habitat is 
lost due to climate change; (2) large areas required to maintain 
connectivity between essential habitats; or (3) increased terrestrial 
denning habitat required due to the loss of suitable sea-ice denning 
habitat.
    Other comments suggested that our proposed critical habitat 
designation was too large, and that specific areas should be excluded: 
(1) For economic reasons; (2) for reasons of national security; (3) due 
to the presence of existing management plans that adequately protect 
polar bears and their habitat; or (4) because the designated critical 
habitat areas did not contain the primary constituent elements (PCEs) 
required for polar bear survival and recovery.

[[Page 76092]]

    All substantive information provided during the comment periods on 
the proposed rule has either been incorporated directly into this final 
determination, incorporated into the final economic analysis, or 
addressed below. Comments received were grouped into general issues 
specifically relating to the proposed critical habitat designation for 
the polar bear, and are addressed in the following summary and 
incorporated into the final rule as appropriate.

Peer Review

    In accordance with our peer review policy published in the Federal 
Register on July 1, 1994 (59 FR 34270), we solicited expert opinions 
from four knowledgeable individuals with scientific expertise that 
included familiarity with polar bear, the geographic region in which it 
occurs, conservation biology principles, and the subsistence and 
cultural needs of Alaska Native people. We received responses from two 
of the peer reviewers. We reviewed all comments we received from the 
peer reviewers for substantive issues and new information regarding 
critical habitat for the polar bear. These comments, which were 
aggregated by subject matter, are summarized and addressed below and 
are incorporated into the final rule as appropriate.

Peer Reviewer Comments

    Comment 1: One peer reviewer commented that the list of eight 
factors influencing polar bear use of habitats is appropriate and 
covers the main points. Missing from the discussion is the issue that 
age, sex, and reproductive status may also affect polar bear use of 
habitats. Evidence of spatial segregation and habitat preference for 
bears of different groups is available in the literature, although it 
is not well studied.
    Our response: We agree and have acknowledged in this final rule 
that habitat use can vary with respect to age, sex, and reproductive 
status.
    Comment 2: One peer reviewer suggested the Service should change 
the scientific name of the ringed seal to Pusa hispida, from the more 
commonly used name Phoca hispida.
    Our response: We concur. The generic name for the ringed seal has 
been moved back and forth between the genus Pusa and Phoca in recent 
decades. Although the designation of Pusa hispida is not universal, we 
defer to the classification of the species as found in the Integrated 
Taxonomic Information System, which places this species in the genus 
Pusa.
    Comment 3: One peer reviewer suggested the Service provide 
supporting documentation for the statement that the energetic demands 
of polar bears are the greatest during the winter season.
    Our response: We agree and have removed the statement from the 
rule, as there is no scientific information to support our assumption.
    Comment 4: One peer reviewer noted that the more recent studies on 
polar bear evolution in sea-ice habitats push the divergence date 
between brown (grizzly) bears and polar bears to somewhere between 1.3-
2.3 million years (Yu et al. 2007, p. 8; Arnason et al. 2007, p. 870), 
although the reviewer recognized that Krause et al. (2008, p. 4) urged 
caution on the time of divergence.
    Our response: We disagree, as the most recently reported date of 
divergence for the brown bear and polar bear lineage is estimated to be 
between 110,000 and 130,000 years before present (Lindqvist et al. 
2010, p. 5,053).
    Comment 5: In the section regarding adaptations unique to polar 
bears, one peer reviewer suggested that the Service should mention 
polar bear behavioral and physiological adaptations such as their 
walking hibernation (serum urea to creatinine ratio) and winter 
activity. These adaptations allow polar bears to remain active in 
winter, unlike, for instance, Grizzly bears in Alaska, which all 
hibernate in winter.
    Our response: We agree and have acknowledged in the Background 
section of this rule that among bear species in the United States that 
occur in Alaska, winter activity and walking hibernation are unique to 
polar bears. Polar bears are highly evolved with respect to survival 
during periods of food deprivation. Polar bears are able to alter their 
metabolism by shifting into a hibernation-like metabolic pattern during 
food shortages. During these periods, active polar bears are able to 
metabolize their fat similar to hibernating polar bears.
    Comment 6: One peer reviewer suggested the Service note that sea 
ice can also ``form over'' the shallower waters of the continental 
shelf due to freezing temperatures, and it is not necessary that the 
ice must be transported to the location as a na[iuml]ve interpretation 
may suggest.
    Our response: We agree and have made the necessary changes to the 
text of this final rule.
    Comment 7: One peer reviewer noted that the only issue of critical 
habitat not explicitly addressed is the use of areas farther offshore 
than the 300 m (984 ft) bathymetric contour. Also, some commenters 
noted that offshore areas in deeper waters are currently used by polar 
bears in the southern Beaufort Sea and are increasing in importance as 
summer refugia. Thus, inclusion of these areas should be considered. 
The reviewer also noted that data on the use of these areas are 
available and in the context that polar bears can be considered a 
migratory species, it is important to consider the connectivity of all 
habitats used by the species.
    Our response: While we acknowledge polar bears temporarily use ice 
over deeper waters when ice is absent from the shallower waters over 
the continental shelf, we believe the ice over deeper waters does not 
contain the biological features of the sea ice that are essential to 
the conservation of the polar bear, such as access to ice seals, to be 
considered critical habitat. We base this on the work of Durner et al. 
(2004, p. 17), which shows that polar bears stay almost entirely over 
the shallower waters of the continental shelf. In terms of providing a 
migratory corridor, see our response to comment 28 of the public 
comments below.
    Comment 8: One peer reviewer suggested that the statement, 
``typically, polar bears tend to avoid humans,'' should include some 
reference to polar bear use of human refuse dumps and attraction to 
camps due to attractants (e.g., food smells).
    Our response: We agree and changed the statement to reflect 
potential anthropogenic attractants (e.g., subsistence-harvested whale 
carcasses, landfills).
    Comment 9: One peer reviewer questioned the statement that ice-
breaking activities may favorably alter essential features and in turn 
allow easier access to ringed seals by polar bears. The reviewer said 
that the statement is speculative and, without a reference, is 
unwarranted. There is no literature supporting ice breaking as allowing 
easier access, and access is only important if it allows an increase in 
kill rate. This is an unsubstantiated claim of benefit.
    Our response: We agree that there is no literature supporting ice 
breaking as allowing easier access to seals. We base our statement on 
our observation of polar bears investigating the broken ice path behind 
a U.S. Coast Guard icebreaker. In addition, we feel we have qualified 
the statement by the use of the word ``may''.
    Comment 10: One peer reviewer noted that the term Chukchi and 
Bering Seas population is used in the text, but the Chukchi and Bering 
Seas population is named the Chukchi Sea (or Alaska and Chukotka) 
population according to the IUCN Polar Bear Specialist Group.

[[Page 76093]]

    Our response: We agree that differing terms may cause confusion and 
will use the term Chukchi-Bering Seas population to describe this 
population consistently throughout the text of this final rule. Using 
the names of the seas where the population resides has been a common 
naming convention used for the Arctic polar bear populations.
    Comment 11: With regard to the statement in the proposed rule, ``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 energetic 
demands * * *'', one peer reviewer suggested the Service provide 
clarification as to the reason why polar bears need to swim.
    Our response: We added text where appropriate to provide 
clarification on the reason polar bears will likely encounter 
increasing distances over which they will need to swim as the summer 
sea-ice edge recedes beyond the continental shelf.
    Comment 12: One peer reviewer stated that the following assertion 
we made needs further documentation: that shelter den importance 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.
    Our response: We believe it is reasonable to infer that a potential 
increase in nutritional stress may lead to an increase in the 
importance of shelter dens to the species. In addition, we believe we 
have sufficiently qualified the statement and provided appropriate 
support for our assertion (see Physical and Biological Features section 
of this final rule for a further discussion of this).

Public Comments

Comments Related to the Need To Designate Critical Habitat and the 
Primary Constituent Elements (PCEs)

    Comment 13: Many commenters questioned the need to designate 
critical habitat for the polar bear. One commenter asserted that the 
Service did not adequately document or explain the basis for its 
assumption that the polar bear critical habitat designation is ``not 
expected to result in additional significant conservation measures.'' 
The commenter asserted that if this is the case, then there is no need 
to designate critical habitat for the polar bear.
    Another commenter stated that if the Department of the Interior's 
projection of climatic warming is accurate, then the areas essential 
for polar bear conservation would be outside the United States (i.e., 
the Canadian Archipelago). They stated that polar bears will likely be 
gone from Alaska in 50 years, and, as a result, designation of critical 
habitat areas in Alaska is not essential to the survival and future 
conservation of polar bears.
    Our response: According to section 4(a)(3)(A) of the Act, the 
Service has a statutory obligation to designate critical habitat for 
endangered and threatened species to the maximum extent prudent and 
determinable. Further, as a result of a lawsuit filed by the Center for 
Biological Diversity, Natural Resources Defense Council, and 
Greenpeace, Inc., we were ordered by the court to designate critical 
habitat if prudent for the polar bear. In the final rule listing the 
polar bear as a threatened species (May 15, 2008, 73 FR 28212) and our 
proposed rule to designate critical habitat (October 29, 2009, 74 FR 
56058), we determined that the designation of critical habitat for the 
polar bear is prudent. Therefore, we are required to designate critical 
habitat for the polar bear to fulfill our legal and statutory 
obligations.
    Given the current conservation measures under section 7 of the Act 
and the Marine Mammal Protection Act (MMPA), we believe that the 
designation will not result in significant additional conservation 
measures. However, critical habitat designation increases the 
protections afforded a listed species by focusing attention on the 
species' habitat needs, and by ensuring that Federal agency actions do 
not destroy or adversely modify designated areas.
    Although the Alaska populations are predicted to decline by mid-
century due to loss of sea ice habitat from climate change, polar bears 
are expected to exist in Alaska in reduced numbers. In addition, it is 
possible that actions taken now to reduce the anthropogenic 
contribution of greenhouse gases could slow the current trend in sea 
ice decline, particularly during the second half of the century. 
Therefore, it is important to protect the essential polar bear habitats 
in Alaska.
    Comment 14: Several commenters suggested that the following PCE 
should be added: unobstructed access to, and absence of disturbance 
from humans and human activity on the sea ice and barrier islands.
    Our response: We believe that the barrier island PCE as described 
in this critical habitat designation adequately provides polar bears 
unimpeded access to sea ice and barrier islands. We base our assertion 
on our experience that a 1.6 km (1 mi) buffer has provided adequate 
protection for known dens from human activities, and the study 
(Anderson and Aars 2008, p. 503) that indicated that females with cubs 
are sensitive to noise disturbance at distances of approximately 1.6 km 
(1 mi). Thus, the no-disturbance zone surrounding the barrier islands 
should adequately protect polar bears denning, resting, or moving along 
the coastal barrier islands from human disturbance. With respect to the 
sea-ice habitat, we believe that the overall level of human disturbance 
would be very low, especially given the remoteness, relatively low 
level of human activity, and extent of the designated sea-ice habitat 
(over 400,000 km\2\ (154,000 mi\2\)).
    Comment 15: Several commenters suggested that the sea ice PCE is 
too narrowly defined as simply the ice itself and currently omits 
biological features essential to the conservation of polar bears. They 
suggest the Service consider including in the PCE: the ice seals 
(primarily ringed and bearded seals) upon which polar bears prey, the 
quality of the water column under the ice, and the biotic community in 
the water column that supports the relatively short Arctic food chain. 
They note that declines in seal pupping have resulted in well-
documented declines in polar bears.
    Our response: Section 3(5)(A)(i) of the Act defines critical 
habitat to include areas within the geographical area occupied by the 
species on which are found those physical or biological features 
essential to the conservation of the species and which may require 
special management considerations or protection. Throughout our 
discussion of critical habitat, we have highlighted the importance of 
ice-dependent seals to polar bears and the importance of sea ice to 
polar bears for normal feeding behavior. The sea ice PCE is intended, 
in part, to identify habitat that supports polar bear prey and normal 
feeding behavior. Therefore, we have added text to the sea ice PCE 
stating that the sea-ice habitat includes adequate prey resources 
(primarily ringed and bearded seals) to support polar bears. We believe 
that the ability of sea-ice habitat to support polar bear prey and 
normal feeding behavior reflects the quality of the water column under 
the sea ice and the quality of the biotic community that supports the 
Arctic food chain.
    Comment 16: One commenter recommended that we conduct additional 
research and denning surveys along the Chukchi Sea coast to reassess 
the coastal region for its potential as critical habitat and determine 
the effects

[[Page 76094]]

on the population as habitat loss issues arise.
    Another commenter suggested the Service should include terrestrial 
denning areas along the Chukchi Sea coast in western Alaska to protect 
occupied and unoccupied denning habitat that may become more important 
with the predicted loss of sea-ice habitat and the stress of over-
hunting.
    Our response: The Service acknowledges that terrestrial denning 
habitat containing the appropriate topographic, and some macrohabitat, 
features occur in areas west of Barrow, Alaska. However, we have added 
access via sea ice to the terrestrial denning habitat PCE because large 
expanses of open water and the timing of ice freeze-up can prohibit 
polar bear access to den sites. For example, denning does not occur on 
Hopen Island, the southernmost island of Svalbard, Norway, when 
freezing of the sea ice occurs too late, which precludes access to den 
sites (Derocher et al. 2004, p. 166). In addition, Fischbach et al. 
(2007, p. 1,402) concluded that terrestrial denning is restricted by 
greater open water fetch. Few bears have been documented to den in 
areas west of Barrow, Alaska (U.S. Geological Survey unpublished data). 
Historically, polar bears from the Chukchi/Bering Seas population have 
not had access to denning habitat in western Alaska because at the end 
of the summer sea melt season large expanses of open water separate the 
bears from western Alaska. Thus, they have used terrestrial denning 
sites on Wrangel Island and the Chukotka Peninsula, areas that are in 
proximity to the sea-ice edge, when the sea ice is at its minimum 
extent in the fall. Presumably, energetic demands limit the ability of 
pregnant polar bears to swim great distances. Therefore, access from 
summer foraging habitats to available terrestrial denning habitats 
would be limited to areas with fall sea-ice access. Thus, we added 
access to suitable terrestrial denning habitat to the terrestrial 
denning habitat PCE. Consequently, we have determined that the areas in 
western Alaska do not contain the specific features essential to the 
conservation of polar bears for terrestrial denning habitat and did not 
designate critical habitat in western Alaska.
    The Service is currently conducting research on the Chukchi-Bering 
Seas polar bear population. We will continue to evaluate the importance 
of these areas in the future as new information becomes available.
    Comment 17: Many commenters, including the State of Alaska, 
indicated that the area proposed for critical habitat designation is 
too large and should be reduced based on a spatial-temporal analysis 
and designated on a seasonal basis or should be dynamic to reflect the 
changing ice conditions throughout the year or even between years. They 
stated that areas with less than 15 percent sea-ice concentration do 
not contain the physical and biological features essential for the 
conservation of polar bears, and that the Service doesn't explain why 
special management measures may be needed for sea-ice habitat, as that 
area is basically uninhabited and inhospitable to humans. They added 
that most of the area is currently unmanaged. Another commenter 
suggested that the Service should develop a system for determining when 
sea-ice conditions meet the three criteria of (a) greater than 50 
percent ice concentration, (b) near leads, open water, or ephemeral 
polynyas, and (c) water depths less than 300 m (984 ft).
    Our response: The Service evaluated the potential for incorporating 
specific seasonal and geographical parameters when designating the sea-
ice critical habitat, but we determined that the extreme variability 
and dynamic nature of the sea ice, especially in the face of climate 
change, made it difficult and impractical to partition the sea-ice 
habitat into meaningful seasonal and geographic units. In addition, 
according to our implementing regulations (50 CFR 424.12(c)), critical 
habitat boundaries should be clearly defined for the public. A 
changeable boundary that was defined based on the seasonal presence of 
sea-ice would not provide the clarity or certainty to the public and 
stakeholders as to which areas are included in critical habitat. It 
also may be in conflict with our regulations which state that we are to 
define the specific areas, and then delineate and describe those areas 
in the regulation of the rule-making. Further, specific case law has 
clarified that the critical habitat need not contain the essential 
features at all times or be used consistently by the species, but 
rather can be used temporally during migration, movement, denning, or 
other life history functions (Arizona Cattle Grower's Ass'n v. Salazar, 
606 F. 3d 1160 (9th Cir. 2010)). We believe that spatial-temporal 
considerations can be evaluated as appropriate for individual projects 
on a case-by-case basis. In addition, Federal agencies and potential 
stakeholders, such as the oil and gas industry, that may need to 
consult based on the designation of critical habitat, need well-defined 
boundaries for planning purposes. Planning projects and assessing 
impacts would be very difficult if the boundaries of critical habitat 
were constantly changing. One of the educational benefits of a critical 
habitat designation is that it provides certainty to consulting 
agencies on the location and extent of critical habitat.
    In response to the second comment on the potential need for special 
management considerations, section 3(5)(A)(i) of the Act states that 
the physical and biological features essential to the conservation of 
the species ``may'' require special management considerations or 
protections. The Act does not state that those features must require 
such management or protection. Nonetheless, the Service believes that 
special management considerations may be necessary due to the expansion 
of offshore oil and gas operations and the absence of the following: 
updated oil spill response plans that adequately deal with polar bears 
and their habitat; demonstrated methods for effective oil spill clean 
up in the broken sea-ice conditions in the Arctic; and adequate 
quantities of oil spill equipment to protect critical habitat. An oil 
spill in Alaska similar to the recent catastrophic oil spill from the 
Deepwater Horizon rig in the Gulf of Mexico would be even more 
difficult to control and clean up effectively due to the extreme Arctic 
conditions, limited resources available locally, and the difficulty of 
accessing these very remote areas particularly during winter.
    Comment 18: One commenter suggested that the Service should create 
an adaptive framework to incorporate a rolling inland boundary for the 
terrestrial critical habitat to account for any Beaufort Sea coastal 
erosion caused by climate change.
    Our response: Jones et al. (2009, p. 2) determined that coastal 
erosion along a 64-km (40-mi) stretch of the Beaufort Sea has more than 
doubled since the mid-1950s to a rate of 13.7 meters per year (m/yr) 
(45 feet per year(ft/yr)) between 2002 and 2007. In our assessment of 
the foreseeable future in the 2008 polar bear listing rule, we 
determined that 45 years was a reasonable timeframe based on the 
reliability of data to assess the threats of climate change and the 
ability to assess the impact of these threats on polar bear 
populations. Using 2050 as the foreseeable future based on the 
predicted loss of sea-ice habitat for the Chukchi-Bering Seas and the 
southern Beaufort Sea populations (Amstrup et al. 2008, p. 231) and 
assuming the rate of coastal erosion (14 m/yr, 46 ft/yr) in the 
Beaufort Sea between 2002 and 2007 (Jones et al. 2009, p. 2) did not 
change,

[[Page 76095]]

we determined that approximately 0.545 km (0.3 mi) of the coast would 
be lost by 2050. Following further evaluation based on the public 
comment, we decided that the method we used to determine the inland 
boundary of the terrestrial denning habitat provides a zone wide enough 
to compensate for changes due to coastal erosion. As new information 
becomes available, we will continue to monitor the situation to 
determine if additional special management considerations are needed.
    In addition, according to our implementing regulations (50 CFR 
424.12(c)), critical habitat boundaries should be clearly defined for 
the public. A changeable boundary that was defined based on extent of 
coastal sea erosion at any particular point in time would not provide 
the clarity or certainty to the public and stakeholders as to which 
areas are included in the critical habitat designation at that time. It 
also may be in conflict with our regulations which state that we are to 
define specific areas, and then delineate and describe those areas in 
the regulation of the rule-making.
    Comment 19: One commenter thought that the proposed critical 
habitat designation is based on the premise that polar bears need vast 
areas of solitude. The commenter further stated that polar bears do not 
need vast areas of solitude as evidenced by congregations around whale 
carcasses.
    Our response: Although polar bears may opportunistically feed on 
whale carcasses, as stated in the proposed rule, their primary prey is 
ice-dependent seals, which are widely distributed in sea ice covering 
the continental shelf. 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. 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). Average activity areas of females in the Chukchi-
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). These figures illustrate 
the large areas typically occupied by polar bears. Thus, the 
designation is based not on the need for solitude but on the activity 
patterns of polar bears, which demonstrate that they need vast areas of 
sea ice to pursue the prey upon which they depend.
    Comment 20: One commenter mentioned that the details of the denning 
habitat in the Barrow area are not defined, so it is difficult to 
determine where the actual denning areas are.
    Our response: The designation of critical habitat is not intended 
to identify actual denning sites but rather to offer protection to the 
essential features that support denning habitat. The U.S. Geological 
Survey (USGS) verified the denning habitat mapped between Barrow, 
Alaska, and the Kavik River, Alaska, during the fall