Endangered and Threatened Wildlife and Plants; 12-Month Petition Finding and Proposed Rule To List the Polar Bear (Ursus maritimus, 1064-1099 [06-9962]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 72, Number 5 (Tuesday, January 9, 2007)]
[Proposed Rules]
[Pages 1064-1099]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-9962]



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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; 12-Month Petition 
Finding and Proposed Rule To List the Polar Bear (Ursus maritimus) as 
Threatened Throughout Its Range; Proposed Rule

Federal Register / Vol. 72, No. 5 / Tuesday, January 9, 2007 / 
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AV19


Endangered and Threatened Wildlife and Plants; 12-Month Petition 
Finding and Proposed Rule To List the Polar Bear (Ursus maritimus) as 
Threatened Throughout Its Range

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule and notice of 12-month finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the polar bear (Ursus maritimus) 
as threatened with critical habitat under the Endangered Species Act of 
1973, as amended (Act). After review of all available scientific and 
commercial information, we find that listing the polar bear as a 
threatened species under the Act is warranted. Accordingly, we herein 
propose to list the polar bear as threatened throughout its range 
pursuant to the Act. This proposed rule, if made final, would extend 
the Act's protections to this species. Critical habitat for the polar 
bear is not determinable at this time. The Service seeks data and 
comments from the public on this proposed listing rule.

DATES: We will consider all comments on this proposed rule received by 
the close of business (5 p.m.) Alaska Local Time on April 9, 2007. 
Requests for a public hearing must be received by the Service on or 
before close of business (5 p.m.) Alaska Local Time on February 23, 
2007.

ADDRESSES: If you wish to comment, you may submit your comments and 
materials concerning this proposed rule by any one of several methods:
    1. You may submit written comments to the Supervisor, U.S. Fish and 
Wildlife Service, Marine Mammals Management Office, 1011 East Tudor 
Road, Anchorage, Alaska 99503.
    2. You may hand deliver written comments to the Marine Mammals 
Management Office at the above address.
    3. You may send comments by electronic mail (e-mail). You may send 
your comments by electronic mail (e-mail) directly to the Service at: 
Polar--Bear--Finding@fws.gov or to the Federal eRulemaking Portal at 
https://www.regulations.gov. See the Public Comments Solicited section 
below for file format for electronic filing and other information.
    The complete file for this finding and proposed rule is available 
for inspection, by appointment, during normal business hours at the 
above address. These documents are also available on the Service's 
Marine Mammal Web site located at: https://alaska.fws.gov/fisheries/mmm/
polarbear/issues.htm.

FOR FURTHER INFORMATION CONTACT: Scott Schliebe, Marine Mammals 
Management Office (see ADDRESSES section) (telephone 907/786-3800). 
Persons who use a telecommunications device for the deaf (TDD) may call 
the Federal Information Relay Service (FIRS) at 1-800-877-8339, 24 
hours a day, 7 days a week.

SUPPLEMENTARY INFORMATION:

Public Comments Solicited

    We intend that any final action resulting from this proposed rule 
will be as accurate and as effective as possible. Therefore, we request 
comments or information from the public, other concerned governmental 
agencies, the scientific community, industry, or any other interested 
party concerning this proposed rule. We particularly seek comments 
concerning:
    (1) Information on taxonomy, distribution, habitat selection 
(especially denning habitat), food habits, population density and 
trends, habitat trends, and effects of management on polar bears;
    (2) Information on the effects of sea ice change on the 
distribution and abundance of polar bears and their principal prey over 
the short and long term;
    (3) Information on the effects of other potential listing factors, 
including oil and gas development, contaminants, ecotourism, hunting, 
poaching, on the distribution and abundance of polar bears and their 
principal prey over the short and long term;
    (4) Information on regulatory mechanisms and management programs 
for polar bear conservation, including mitigation measures related to 
oil and gas exploration and development, hunting conservation programs, 
anti-poaching programs, and any other private, tribal, or governmental 
conservation programs which benefit polar bears;
    (5) The specific physical and biological features to consider, and 
specific areas that may meet the definition of critical habitat and 
that should or should not be considered for a proposed critical habitat 
designation as provided by section 4 of the Act;
    (6) Information relevant to whether any populations of the species 
may qualify as distinct population segments; and
    (7) The data and studies refered to within this proposal.
    If you wish to comment, you may submit your comments and materials 
concerning this proposed rule by any one of several methods, as listed 
above in the ADDRESSES section. If you submit comments by e-mail, 
please submit them in ASCII file format and avoid the use of special 
characters and encryption. Please include ``Attn: Polar Bear Finding'' 
and your name and return address in your e-mail message. Please note 
that the e-mail address will be closed at the termination of the public 
comment period.
    Our practice is to make comments, including names and home 
addresses of respondents, available for public review during regular 
business hours. Individual respondents may request that we withhold 
their names and/or home addresses, etc., but if you wish us to consider 
withholding this information, you must state this prominently at the 
beginning of your comments. In addition, you must present rationale for 
withholding this information. This rationale must demonstrate that 
disclosure would constitute a clearly unwarranted invasion of privacy. 
Unsupported assertions will not meet this burden. In the absence of 
exceptional, documentable circumstances, this information will be 
released. We will always make submissions from organizations or 
businesses, and from individuals identifying themselves as 
representatives of or officials of organizations or businesses, 
available for public inspection in their entirety. Comments and 
materials received will be available for public inspection, by 
appointment, during normal business hours at the U.S. Fish and Wildlife 
Service Office at the address listed in ADDRESSES.

Background

    Section 4(b)(3)(A) of the Act (16 U.S.C. 1531 et seq. requires 
that, for any petition to add a species to, remove a species from, or 
reclassify a species on one of the Lists of Endangered and Threatened 
Wildlife and Plants, we first make a determination whether the petition 
presents substantial scientific or commercial information indicating 
that the petitioned action may be warranted. To the maximum extent 
practicable, this determination is to be made within 90 days of receipt 
of the petition, and published promptly in the Federal Register.
    If the petition is found to present substantial information, 
section

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4(b)(3)(A) of the Act requires us to commence a status review of the 
species, and section 4(b)(3)(B) of the Act requires us to make a second 
finding, this one within 12 months of the date of receipt of the 
petition, on whether the petitioned action is: (a) Not warranted; (b) 
warranted; or (c) warranted but precluded (i.e., the immediate proposal 
of a regulation implementing the petitioned action is precluded by 
other pending proposals to determine whether any species is threatened 
or endangered, and expeditious progress is being made to add or remove 
qualified species from the Lists of Endangered and Threatened Wildlife 
and Plants). This determination is likewise to be published promptly in 
the Federal Register.
    Species for which listing is warranted but precluded are considered 
to be ``candidates'' for listing. Section 4(b)(3)(C) of the Act 
requires that a petition for which the requested action is found to be 
warranted but precluded be treated as though resubmitted on the date of 
such finding, i.e., requiring a subsequent finding to be made within 12 
months. Each subsequent 12-month finding is also to be in the Federal 
Register. We typically publish these findings in our Candidate Notice 
of Review (CNOR). Our most recent CNOR was published on September 12, 
2006 (71 FR 53756).

Previous Federal Action

    On February 17, 2005, we received a petition from the Center for 
Biological Diversity, dated February 16, 2005, requesting that we list 
the polar bear as threatened throughout its range, and that critical 
habitat be designated concurrently with the listing. The petition was 
clearly identified as such, and contained the name, authorized 
signature, and address of the requesting party. Included in the 
petition was supporting information regarding the species' taxonomy and 
ecology, historical and current distribution, present status, and 
actual and potential causes of decline. We acknowledged the receipt of 
the petition in a letter dated July 1, 2005. In that letter, we also 
advised the petitioners that, due to funding constraints in fiscal year 
(FY) 2005, and the need to comply with court orders and settlement 
agreements, we would not be able to begin processing the petition at 
that time.
    In a letter dated July 5, 2005, the petitioner informed us that two 
additional parties were joining as petitioners: the Natural Resources 
Defense Council and Greenpeace, Inc. In the same letter, the 
petitioners informed us of two new scientific articles, Hansen et al. 
(2005) and Stroeve et al. (2005), that they wanted us to consider when 
conducting our evaluation of the petition to list the polar bear. In a 
letter we received on December 27, 2005, the petitioners submitted 
additional new information to be considered, along with the information 
in the initial petition, in making our 90-day finding.
    On December 15, 2005, the petitioners filed a complaint for 
declaratory and injunctive relief in the United States District Court 
for the Northern District of California, challenging our failure to 
issue a 90-day finding in response to the petition as required by 
section 4(b)(3) of the Act. On February 7, 2006, we made our 90-day 
finding that the petition presented substantial scientific information 
indicating that listing the polar bear may be warranted; the finding 
and our initiation of a status review was published in the Federal 
Register on February 9, 2006 (71 FR 6745). In a stipulated settlement 
agreement approved by the Court on July 5, 2006, we agreed to submit a 
12-month finding to the Federal Register by December 27, 2006. This 
notice constitutes our 12-month finding for the petition to list the 
polar bear as threatened, in fulfillment of the stipulated settlement 
agreement.

Status Assessment

    Pursuant to section 4(b)(3)(A) of the Act, we conducted a status 
review of the polar bear. With this notice we announce the completion 
and availability of the Polar Bear Status Assessment (Status Assessment 
or Schliebe et al. (2006a)). The Status Assessment was compiled and 
edited by staff of the Service's Marine Mammals Management Office of 
Region 7 (Scott Schliebe; Thomas Evans; Kurt Johnson, Ph.D.; Michael 
Roy, Ph.D.; Susanne Miller; Charles Hamilton; Rosa Meehan, Ph.D.; and 
Sonja Jahrsdoerfer). Information contained in the original petition, as 
well as additional information provided by the petitioners, was 
considered during the development of the Status Assessment. In 
addition, all comments received from the public during the open public 
comment period were considered. To ensure that the Status Assessment 
would be complete and based on the best available scientific and 
commercial information, we solicited information from the public on the 
status of the polar bear in two separate public comment periods 
announced in the Federal Register (February 9, 2006; 71 FR 6745) and 
(May 17, 2006; 71 FR 28653). In addition, all available scientific and 
commercial information on polar bears and threats to polar bears was 
reviewed and considered during development of the the Status Assessment 
and proposed rule.
    In accordance with Service policies, peer review of the draft 
Status Assessment was sought from 12 independent experts in the fields 
of polar bear ecology, contaminants and physiology, climatic science 
and physics, and traditional ecological knowledge. Comments were 
received from 10 peer reviewers, and those comments were addressed in 
revisions to the draft Status Assessment. The Status Assessment, a list 
of peer reviewers, and comments received from peer reviewers are 
available upon request from the Marine Mammals Management Office as 
well as on the Service's Marine Mammal Web site located at: https://
alaska.fws.gov/fisheries/mmm/polarbear/issues.htm. Literature cited in 
the Status Assessment serves as the basis for the 12-month finding and 
proposed rule.

Species Biology

    Information presented in this section is summarized from the Status 
Assessment (Schliebe et al. 2006a). For more detailed information on 
the biology of the polar bear, please consult the Status Assessment.

Taxonomy and Evolution

    Throughout the Arctic, polar bears are known by a variety of common 
names, including nanook, nanuq, ice bear, sea bear, isbj[oslash]rn, 
white bears, and eisb[auml]r. Phipps (1774) first proposed and 
described polar bear as a species distinct from other bears and 
provided a scientific name Ursus maritimus. A number of alternative 
names followed, but Harington (1966), Manning (1971, p. 9), and Wilson 
(1976) (all three references cited in Amstrup 2003, p. 587) 
subsequently promoted the name Ursus maritimus that has been used 
since. The polar bear is usually considered a marine mammal since its 
primary habitat is the sea ice (Amstrup 2003, p. 587), and it is 
evolutionarily adapted to life on sea ice (see further discussion under 
General Description section). The polar bear was included on the list 
of species covered under the U.S. Marine Mammal Protection Act of 1972 
as amended (16 U.S.C. 1361 et seq.) (MMPA).
    Genetic research has confirmed that polar bears evolved from 
grizzly (brown) bears (Ursus arctos) 250 to 300 thousand years ago 
(Cronin et al. 1991, p. 2990; Talbot and Shields 1996a, p. 574). Only 
in portions of northern Canada and northern Alaska do the ranges of 
polar bears and grizzly bears overlap. Cross-breeding of grizzly bears 
and polar bears in captivity has produced

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reproductively viable offspring (Gray 1972; Stirling 1988, p. 23). The 
first documented case of cross-breeding in the wild was reported in the 
spring of 2006.

General Description

    Polar bears are the largest of the living bear species (DeMaster 
and Stirling 1981 p. 1; Stirling and Derocher 1990 p. 190). They 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 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 grizzly bears. The nose, 
lips, and skin of polar bears are black (Demaster and Stirling 1981 p. 
1; Amstrup 2003 p. 588).
    Polar bears are evolutionarily adapted to life on sea ice. 
Adaptations to this life include: (1) White pelage with water-repellent 
guard hairs and dense underfur; (2) a short furred snout; (3) small 
ears for reduced surface area; (4) teeth specialized for a carnivorous 
rather than an omnivorous diet; and (5) feet with tiny papillae and 
``suction cups'' on the underside, for increased 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 grizzly bears, and larger and heavier 
than those of black bears (Ursus americanus) (Amstrup 2003, p. 589).

Distribution and Movements

    Polar bears evolved to utilize the Arctic sea ice niche and are 
distributed throughout most ice-covered seas of the Northern 
Hemisphere. They are generally limited to areas where the sea is ice-
covered for much of the year; however, polar bears are not evenly 
distributed throughout their range. They are most abundant near the 
shore in shallow-water areas, and in other areas where currents and 
ocean upwelling increase marine productivity and serve to keep the ice 
cover from becoming too solidified 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. 
2607; Amstrup et al. 2000b, p. 960). Over most of their range, polar 
bears remain on the sea ice year-round or spend only short periods on 
land. They occur throughout the East Siberian, Laptev, and Kara Seas of 
Russia; Fram Strait, Greenland Sea, and Barents Sea of northern Europe 
(Norway and Greenland (Denmark)); Baffin Bay, which separates Canada 
and Greenland, through most of the Canadian Arctic archipelago and the 
Canadian Beaufort Sea; and in the Chukchi and Beaufort Seas located 
west and north of Alaska.
    The distribution of polar bears in most areas varies seasonally 
with the seasonal extent of sea ice cover and availability of prey. In 
Alaska in the winter, sea ice may extend 400 kilometers (km) (248 miles 
(mi)) south of the Bering Strait, and polar bears will extend their 
range to the southernmost proximity of the ice (Ray 1971, cited in 
Amstrup 2003, p. 587). 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 pack ice (Garner et al. 1990, p. 222; Garner at al. 1994b, 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. Significant northerly and southerly movements of polar bears 
appear to depend on seasonal melting and refreezing of ice (Amstrup et 
al. 2000, p. 142). In other areas, for example, when the sea ice melts 
in Hudson Bay, James Bay, Davis Strait, Baffin Bay, portions of the 
Canadian High Arctic, and some portions of the Barents Sea, polar bears 
remain on land for up to several months while they wait for winter and 
new ice to form (Jonkel et al. 1976; Schweinsburg 1979; Prevett and 
Kolenosky 1982; Schweinsburg and Lee 1982; Ferguson et al. 1997; Lunn 
et al. 1997 all cited in Amstrup 2003, p. 587; Mauritzen et al. 2001, 
p. 1710).
    The distribution patterns of some polar bear populations during the 
open water and early fall seasons have changed in recent years. In the 
Beaufort Sea, for example, greater numbers of polar bears are being 
found on shore during this period than recorded at any previous time 
(Schliebe et al. 2006b, p. 559). In Baffin Bay, Davis Strait, western 
Hudson Bay and other areas of Canada, Inuit hunters are reporting an 
increase in the numbers of bears present on land during summer and fall 
(Dowsley and Taylor 2005, p. 2; Dowsley 2005, p. 2). The exact reasons 
for changes may involve a number of factors, including changes in sea 
ice (Stirling and Parkinson 2006, p. 272).
    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). Results show strong fidelity to activity areas 
that are used over multiple years. Some polar bear populations are 
closely associated with pack ice. In the Chukchi and Beaufort Sea areas 
of Alaska and northwestern Canada, less than 10 percent of the polar 
bear locations obtained were on land (Amstrup 2000, p. 137; Amstrup, 
USGS, unpublished data); the majority of the land locations were 
locations with bears occupying maternal dens during the winter. A 
similar pattern was found in East Greenland (Wiig et al. 2003, p. 511). 
In the absence of ice during the summer season, some populations of 
polar bears in eastern Canada, Hudson Bay, and the Barents Sea are 
remaining on land for protracted periods of time until ice again forms 
and provides a platform for them to move to sea ice.

Food Habits

    Polar bears are carnivorous and an upper level predator of the 
Arctic marine ecosystem. Polar bears prey heavily throughout their 
range on ringed seals (Phoca hispida) and, to a lesser extent, bearded 
seals (Erignathus barbatus) and in some locales, other seal species. On 
average, an adult polar bear needs approximately 2 kg (4.4 lbs) of seal 
fat per day to survive (Best 1985, p. 1035). Sufficient nutrition is 
critical and may be obtained and stored as fat when prey is abundant.
    Although seals are their primary prey, polar bears also have been 
known to kill much larger animals such as walruses (Odobenus rosmarus), 
narwhal (Monodon monoceros), and belugas (Delphinapterus leucas) 
(Kiliaan et al. 1978; Smith 1980, p. 2206; Smith 1985; 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 and carrion other 
than seals may be quite important to polar bear sustenance. Stirling 
and [Oslash]ritsland (1995, p. 2609) suggested that in areas where 
ringed seal populations were reduced, other prey species were being 
substituted. Like other ursids, polar bears will eat human garbage 
(Lunn and Stirling 1985, p. 2295), and when confined to land for long 
periods they will consume coastal marine and terrestrial plants and 
other terrestrial foods (Russell 1975, p. 122; Derocher et al. 1993, p. 
252), but the significance of other terrestrial foods to polar bears 
may be limited (Lunn and Stirling 1985, p. 2296; Ramsay and Hobson 
1991, p. 600; Derocher et al. 2004, p. 169).

Reproduction

    Polar bears are characterized by a late age at sexual maturity, 
small litter sizes, and extended parental investment in raising young, 
factors that combine to contribute to a very low reproductive

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rate. Reproduction in the female polar bear is similar to that in other 
ursids (bears).
    Females generally mature and breed for the first time at 4 or 5 
years and give birth at 5 or 6 years of age. Litters of two cubs are 
most common, but litters of three cubs are seen sporadically across the 
Arctic. When foraging conditions are difficult, polar bears may 
``defer'' reproduction in favor of survival (Derocher et al. 1992, p. 
564).
    Polar bears enter a prolonged estrus between March and June, when 
breeding occurs. Ovulation is thought to be induced by mating (Wimsatt 
1963; Ramsay and Dunbrack 1986; Derocher and Stirling 1992; all cited 
in Amstrup 2003, p. 599), and implantation is delayed until autumn. The 
total gestation period is 195 to 265 days (Uspenski 1977 cited in 
Amstrup 2003, p. 599), although active development of the fetus is 
suspended during most of this period. The timing of implantation, and 
therefore the timing of birth, is likely dependent on body condition of 
the female, which depends on a variety of environmental factors.
    Newborn polar bears are helpless, have hair, but are blind and 
weigh only 0.6 kg (1.3 lb) (Blix and Lentfer 1979, p. 68). Cubs grow 
rapidly, and may weigh 10 to 12 kg (22 to 26 lbs) by the time they 
emerge from the den in the spring. Young bears will stay with their 
mothers until weaning, which occurs most commonly in early spring when 
the cubs are 2.3 years of age. Female polar bears are available to 
breed again after their cubs are weaned, so the reproductive interval 
for polar bears is 3 years.
    Polar bears are long-lived mammals not generally susceptable to 
disease, parasites, or injury. The oldest known female in the wild was 
32 years of age and the oldest known male was 28, though few polar 
bears in the wild live to be older than 20 (Stirling 1988, p. 139; 
Stirling 1990, p. 225). Due to extremely low reproductive rates, polar 
bears require a high rate of survival to maintain population levels. 
Survival rates increase up to a certain age, with cubs-of-the-year 
having the lowest rates and prime age adults (between 5 and 20 years of 
age) having survival rates that can exceed 90 percent.

Polar Bear--Sea Ice Habitat Relationships

    Polar bears are distributed throughout the ice-covered waters of 
the circumpolar Arctic (Stirling 1988, p. 61), and are reliant on the 
sea ice as their primary habitat (Amstrup 2003, p. 587). 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 to move 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. (2003, 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 with less prey. Their findings indicate that polar 
bear distribution may not be solely a reflection of prey availability, 
but other factors such as energetic costs or risk may be involved.
    Stirling et al. (1993, p. 15) defined seven types of sea ice 
habitat and classified polar bear use of these ice types based on the 
presence of bears or tracks in order to determine habitat preferences. 
The seven types of sea ice were: stable fast ice with drifts; stable 
fast ice without drifts; floe edge ice; moving ice; continuous stable 
pressure ridges; coastal low level pressure ridges; and fiords and 
bays. Polar bears were not evenly distributed over these sea ice 
habitats, but concentrated on the floe ice edge, on stable fast ice 
with drifts, and on areas of moving ice (Stirling 1990 p. 226; Stirling 
et al. 1993, p. 18). In another assessment, categories of ice types 
included: pack ice; shore-fast ice; transition zone ice; and polynyas 
(i.e., open water areas within the ice); and leads (USFWS 1995, p. 9). 
Pack ice, which consists of annual and multi-year ice in constant 
motion due to winds and currents, is the primary summer habitat for 
Alaskan polar bears. Shore-fast ice is used for feeding on seal pups, 
movements, and occasionally for maternity denning. Open water at leads 
and polynyas attracts seals and other marine mammals and provides 
preferred hunting habitats during winter and spring.
    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). In some areas, such as Hudson Bay and James Bay, polar bears remain 
on land when the sea ice retreats in the spring and they fast for 
several months (up to 8 months for pregnant females) before fall 
freeze-up (Stirling 1988, p. 63; Derocher et al. 2004, p. 163). Some 
populations unconstrained by land masses, such as those in the Barents, 
Chukchi and Beaufort Seas, spend each summer on the multiyear ice of 
the polar basin (Derocher et al. 2004, p. 163). In intermediate areas 
such as the Canadian Arctic, Svalbard, and Franz Josef Land 
archipelagos, bears stay with the ice most of the time, but in some 
years they may spend up to a few months on land (Mauritizen et al. 
2001, p. 1710). Most populations use terrestrial habitat partially or 
exclusively for maternity denning; therefore, females must adjust their 
movements in order to access land at the appropriate time (Stirling 
1988, p. 64; Derocher et al. 2004, p. 166).
    Sea ice changes between years in response to environmental factors 
may have consequences to the distribution and productivity of polar 
bears as well as their prey. In the southern Beaufort Sea, anomalous 
heavy ice conditions in the mid-1970s and mid-1980s (thought to be 
roughly in phase with a similar variation in runoff from the MacKenzie 
River) caused significant declines in productivity of ringed seals 
(Stirling 2002, p. 68). Each event lasted approximately three years and 
caused similar declines in the natality of polar bears and survival of 
subadults, after which reproductive success and survival of both 
species increased again.

Maternal Denning Habitat

    Throughout the species' range, most pregnant female polar bears 
excavate dens in snow located on land in the fall-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; Ramsey and Stirling 1990, p. 233), 
and in the southern Beaufort Sea, where a portion of the population 
dens in snow caves located on pack and shorefast ice. Successful 
denning by polar bears requires accumulation of sufficient snow for den 
construction and maintenance. Adequate and timely snowfall combined 
with winds that cause snow accumulation leeward of topographic features 
create denning habitat (Harington 1968, p.12).
    A great amount of polar bear denning occurs in core areas 
(Harington 1968, pp. 7-8) which show high use over time. In some 
portions of the species' range, polar bears den in a more diffuse 
pattern, 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. 81; Ferguson et al. 2000a, p. 1125; Durner 
et al. 2001, p. 117; Durner et al. 2003, p. 57).
    Habitat characteristics of denning areas vary substantially from 
the rugged

[[Page 1068]]

mountains and fjordlands of the Svalbard archipelago and the large 
islands north of the Russian coast (L[oslash]n[oslash] 1970, p. 77; 
Uspenski and Kistchinski 1972, p. 182; Larsen 1985, pp. 321-322) to the 
relatively flat topography of areas such as the west coast of Hudson 
Bay (Ramsay and Andriashek 1986, p. 9; Ramsay and Stirling 1990, p. 
233) and north slope of Alaska (Amstrup 1993, p. 247; Amstrup and 
Gardner 1994, p. 7; Durner et al. 2001, p. 119; Durner et al. 2003, p. 
61), to offshore pack ice-pressure ridge habitat. 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). 
Across the range, most polar bear dens occur relatively near the coast. 
The main exception to coastal denning occurs in the western Hudson Bay 
area, where bears den further inland in traditional denning areas 
(Kolenosky and Prevett 1983, pp. 243-244; Stirling and Ramsay 1986, p. 
349).
    Polar bears are largely food deprived while on land in the ice-free 
period; during this time they survive on stored fat reserves. Pregnant 
females that spend the late summer on land prior to denning may not 
feed for 8 months (Watts and Stirling 1988, p. 627). This may be the 
longest period of food deprivation of any mammal, and it occurs at a 
time when the female gives birth to and then nourishes new cubs.

Current Population Status and Trend

    The total number of polar bears worldwide is estimated to be 
20,000-25,000. Polar bears are not evenly distributed throughout the 
Arctic, nor do they comprise a single nomadic cosmopolitan population, 
but rather occur in 19 relatively discrete populations (Figure 1). The 
boundaries of these populations are based on behavioral and ecological 
factors and were developed from decades of intensive scientific studies 
as well as traditional knowledge (Lunn et al. 2002, p. 41). Although 
there is overlap in areas occupied by members of the populations, with 
the exception of the Arctic Basin population, these boundaries are 
sufficiently discrete to manage the populations independently. 
Correspondence between genetic data and movement data reinforces 
current population designations (Paetkau et al. 1999, p. 1571; Amstrup 
2003, p. 590).
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[GRAPHIC] [TIFF OMITTED] TP09JA07.000

    Population size estimates and qualitative categories of the current 
trend and status data for each polar bear population are discussed 
below. This discussion was derived from information presented at the 
World Conservation Union--International Union for Conservation of 
Nature and Natural Resources, Species Survival Commission (IUCN/SSC) 
Polar Bear Specialist Group (PBSG) meeting held in Seattle, Washington, 
in June 2005, and updated with results that became available as of 
October 2006 (PBSG 2006). The information on each

[[Page 1070]]

population is based on the available status reports and revisions given 
by each nation. Categories of status include an assessment of whether 
populations are not reduced, reduced, or severely reduced from historic 
levels of abundance, or if insufficient data are available to estimate 
status. Categories of trend include an assessment of whether the 
population is currently increasing, stable, or declining, or if 
insufficient data are available to estimate trend. The current status 
and trend assessments do not consider the various factors that have 
been determined to threaten the species within the foreseeable future, 
as discussed later in this document in the five-factor analysis 
sections.
    The East Greenland population number is unknown since no population 
surveys have been conducted in the past. The status and trend have not 
been determined due to the absence of abundance data. The Barents Sea 
population was estimated to comprise 3,000 animals based on the only 
population survey conducted in this vast area during 2004. Because only 
one abundance estimate is available, the status and trend cannot yet be 
determined. The Kara Sea population number is unknown because 
population surveys have not been conducted; thus status and trend of 
this population cannot yet be determined. The Laptev Sea population is 
estimated to comprise 800 to 1,200 animals, based on an extrapolation 
of historical aerial den survey data. Status and trend cannot yet be 
determined for this population. The Chukchi Sea population is estimated 
to comprise 2,000 animals based on extrapolation of aerial den surveys. 
Status and trend cannot yet be determined for this population. The 
Southern Beaufort Sea population is comprised of 1,500 animals based on 
conclusion of a recent population inventory. The predicted trend is 
declining and the status is designated as reduced. The Northern 
Beaufort Sea population is comprised of 1,200 animals. The trend is 
designated as stable and status is determined to be not reduced, 
although a new abundance estimate will be developed in the near future. 
The Viscount-Melville population is estimated to comprise 215 animals. 
The trend is increasing although the status is designated as severely 
reduced from prior excessive harvest. The Norwegian Bay population 
number is 190 animals and the trend is noted as declining while the 
status is listed as not reduced. The Lancaster Sound population is 
estimated to be 2,541 animals and the trend is stable and status is not 
reduced. The M'Clintock Channel population is estimated at 284 animals 
and the trend is increasing although the status is severely reduced 
from excessive harvest. The Gulf of Boothia population abundance 
estimate is 1,523 animals and the trend is stable and status is 
designated as not reduced. The Foxe Basin population comprises 2,197 
animals and the population trend is stable and the status is not 
reduced. The Western Hudson Bay population estimate is 935 animals and 
the trend is declining and the status is reduced. The Southern Hudson 
Bay population estimate is 1,000 animals and the trend is stable and 
status is not reduced. The Kane Basin population is comprised of 164 
animals and its trend is declining and status is reduced. The Baffin 
Bay population is estimated to be 2,074 animals and the trend is 
declining and status is reduced. The Davis Strait population is 
estimated at 1,650 animals based on traditional ecological knowledge 
(TEK) and data are unavailable to assess trends or status. The Arctic 
Basin population estimate, trend, and status are unknown.
    For populations with long-term data we can establish trends, but 
cannot do so for populations with short-term or lack of data. Of the 
populations for which data are available to assess status and trend, 
two are noted to be increasing (Viscount Melville and M'Clintock 
Channel). Both of these populations were severely reduced in the past 
and are recovering under conservative harvest limits. The two 
populations with the most extensive time series of data, Western Hudson 
Bay and Southern Beaufort Sea, are both declining. However, based on 
environmental factors and observed patterns of population trends for 
some populations it is likely that most populations will exhibit 
declines in the future.

Summary of Factors Affecting the Polar Bear

    Section 4 of the Act (16 U.S.C. 1533), and implementing regulations 
at 50 CFR part 424, set forth procedures for adding species to the 
Federal List of Endangered and Threatened Species. Under section 4(a) 
of the Act, we may list a species on the basis of any of five factors, 
as follows: (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range; (B) overutilization for 
commercial, recreational, scientific, or educational purposes; (C) 
disease or predation; (D) the inadequacy of existing regulatory 
mechanisms; or (E) other natural or manmade factors affecting its 
continued existence. In making this finding, information regarding the 
status and trends of the polar bear is considered in relation to the 
five factors provided in section 4(a)(1) of the Act.
    In the context of the Act, the term ``threatened species'' means 
any species or subspecies or, for vertebrates, Distinct Population 
Segment (DPS) that is likely to become an endangered species within the 
foreseeable future throughout all or a significant portion of its 
range. The term ``endangered species'' means any species that is in 
danger of extinction throughout all or a significant portion of its 
range. The Act does not define the term ``foreseeable future.'' The 
PBSG, when they reassessed the status of polar bears globally in June 
2005, used the criteria described in the IUCN/SSC Red List process 
(IUCN 2004) to determine which Red List category the polar bear should 
be assigned. The criteria, used for all species that IUCN assesses in 
the Red List process, use observed, estimated, inferred or suspected 
population size reductions of a certain percentage over the last 10 
years or three generations, whichever is the longer to categorize 
species. A generation, as defined by IUCN, is calculated as the age of 
sexual maturity (5 years) plus 50 percent of the length of the lifetime 
reproductive period (20 years). Based on these calculations, the 
projected length of 1 generation for a polar bear was calculated at 15 
years, and the projected period for 3 generations was calculated as 45 
years.
    For another species evaluated for listing as threatened, the 
Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri), the status 
assessment report (May et al. 2003 p. 10) considered the ``foreseeable 
future'' to be 2-3 decades (4 to 10 generations), depending on the 
productivity of the environment. For the greater sage grouse 
(Centrocercus urophasianus) the status reviewers agreed that given all 
of the uncertainties, a reasonable timeframe for ``foreseeable future'' 
for the threatened definition was approximately 30 to 100 years 
[approximately 10 greater sage-grouse generations or 2 sagebrush 
habitat regeneration cycles (70 FR 2244)].
    Given the IUCN criteria, the life-history and population dynamics 
of polar bears, documented changes to date in both multi-year and 
annual sea ice, and the direction of projected rates of change of sea 
ice in future decades, we consider the three generation timespan used 
in the IUCN Red List criteria to be a reasonable projection of 
foreseeable future and provides a time frame for analysis of whether 
polar bears are likely to become endangered. Therefore,

[[Page 1071]]

45 years is the ``foreseeable future'' for the polar bear. This time 
frame is long enough to take into account multi-generational population 
dynamics and the capacity for ecological adaptation (Schliebe et al. 
2006a).
    We considered all relevant, available information under each of the 
listing factors in the context of present-day polar bear distribution. 
Our evaluation of the five factors with respect to polar bear 
populations is presented below. While the polar bear can be delineated 
into 19 populations, and population-specific interaction of various 
listing factors may affect these populations at different levels or 
rates, in this 12-month finding and proposed rule we evaluated the 
status of the species throughout its entire range because we find that 
the entire species meets the definition of a threatened species under 
the Act. Accordingly, we have not considered the petitioners' 
alternative of assessing whether listing of particular distinct 
population segments is warranted.

A. Present or Threatened Destruction, Modification, or Curtailment of 
the Species' Habitat or Range

    Polar bears are believed to be completely dependent upon Arctic sea 
ice for survival (Moore and Huntington, in press; Laidre et al. in 
prep.). They need sea ice as a platform for hunting, for seasonal 
movements, for travel to terrestrial denning areas, for resting, and 
for mating. Some polar bears use terrestrial habitats seasonally, such 
as pregnant females for denning and some bears, all sex and age 
classes, for resting during open water periods. While open water may 
not be an essential habitat for polar bears because life functions such 
as feeding, reproduction or resting do not occur in open water, open 
water is a fundamental part of the marine system that supports seal 
species, the principal prey of polar bears, and seasonally returns to 
ice in the form needed by the bears. Further, the open water interface 
with sea ice is an important habitat in that it is used to a great 
extent by polar bears. The extent of open water is important because 
vast areas of open water may limit a bear's ability to access sea ice 
or land. Snow cover is also an important component of polar bear 
habitat in that it provides insulation and cover for young polar bears 
and ringed seals in snow dens or lairs.
Overview of Arctic Sea Ice Change
    Initial syntheses of climate models and environmental change data 
have identified potentially significant changes to the landscapes and 
biota in Arctic regions as a consequence of climate change (ACIA 2005, 
p. 1017; IPCC 2001a, p. 920). Climate trends are not occurring evenly 
or in a linear fashion throughout the world; Arctic regions are being 
disproportionately affected by higher levels of warming (Overpeck 2006, 
p. 1749). Observations of Arctic changes, including diminishing sea 
ice, shrinking glaciers, thawing permafrost, and Arctic greening, 
validate earlier findings (Morison et al. 2000, p. 360; Sturm et al. 
2003, pp. 63-65; Comiso and Parkinson 2004, pp. 38-43; Parkinson in 
press).
    Additional studies indicate that previous projections regarding the 
rate and extent of climate change underestimated the temperature trend, 
reductions to annual sea ice during the summer and winter periods, 
reductions to multi-year pack ice, and reductions in thickness 
(Rothrock et al. 2003, p. 3471; Stroeve et al. 2005, p. 2). Overpeck et 
al. (2005, p. 309) indicated that the Arctic is moving toward a new 
``super interglacial'' state that falls outside of natural glacial-
interglacial periods that have characterized the past 800,000 years. 
These changes appear to be driven largely by the albedo effect (see 
explanation in following paragraph), and there are few, if any, 
processes that are capable of altering this trajectory. There is no 
paleoclimatic evidence for a seasonally ice-free Arctic during the past 
800,000 years (Overpeck et al. 2005, p. 309).
    The National Snow and Ice Data Center (NSIDC is part of the 
University of Colorado Cooperative Institute for Research in 
Environmental Sciences, and is affiliated with the National Oceanic and 
Atmospheric Administration National Geophysical Data Center through a 
cooperative agreement) reported that the amount of sea ice in 2006 was 
the second lowest on record (since satellites began recording sea ice 
extent measurements via passive microwave imagery in 1978), and the 
pace of melting was accelerating. The latest sea ice measurements are 
thought to indicate that ice melt is accelerating due to a positive 
feedback loop. The albedo effect involves reduction of the extent of 
lighter-colored sea ice or snow, which reflects solar energy back into 
the atmosphere, and a corresponding increase in the extent of darker-
colored water or land that absorbs more of the sun's energy. This 
greater absorption of energy causes faster melting, which in turn 
causes more warming, and thus creates a self-reinforcing cycle that 
becomes amplified and accelerates with time. Lindsay and Zhang (2005, 
p. 4892) suggest that feedback mechanisms caused a tipping point in 
Arctic sea ice thinning in the late 1980s, sustaining a continual 
decline in sea ice cover that cannot easily be reversed. Results of a 
new study by a team of scientists from the National Center for 
Atmospheric Research and two universities, using projections from a 
state-of-the-art community climate system model, suggest that abrupt 
reductions in the extent of summer ice are likely to occur over the 
next few decades, and that near ice-free September conditions may be 
reached as early as 2040 (Holland et al, 2006).
Observed and Projected Changes in Arctic Sea Ice
    Sea ice is the defining characteristic of the marine Arctic and has 
a strong seasonal cycle (ACIA 2005, p. 30). It is typically at its 
maximum extent in March and minimum extent in September (Parkinson et 
al. 1999, p. 20, 840). There is considerable inter-annual variability 
both in the maximum and minimum extent of sea ice. In addition, there 
are decadal and inter-decadal fluctuations to sea ice extent due to 
changes in atmospheric pressure patterns and their associated winds, 
continental discharge, and influx of Atlantic and Pacific waters 
(Gloersen 1995, p. 505; Mysak and Manak 1989, p. 402; Kwok 2000, p. 
776; Parkinson 2000b, p. 10; Polyakov et al. 2003, p. 2080; Rigor et 
al. 2002, p. 2660; Zakharov 1994, p. 42).
    Observations have shown a decline in late summer Arctic sea ice 
extent of 7.7 percent per decade and in the perennial sea ice area of 
up to 9.8 percent per decade since 1978 (Stroeve et al. 2005, p.1; 
Comiso 2006, p. 75). A lesser decline of 2.7 percent per decade has 
been observed in yearly averaged sea ice extents (Parkinson and 
Cavalieri 2002, p. 441). The rate of decrease appears to be 
accelerating, with record low minimum extents in the sea ice cover 
recorded during 2002 through 2005 (Stroeve et al. in press; Comiso 
2006, p. 75). Average air temperatures across most of the Arctic Ocean 
from January to August 2006 were about 2 to 7 degrees Fahrenheit 
([deg]F) warmer than the long-term average across the region during the 
preceding 50 years, indicating that ice melt is accelerating due to a 
positive feedback loop that enhances warming through the albedo effect. 
Observations have likewise shown a thinning of the Arctic sea ice of 32 
percent or more from the 1960s and 1970s to the 1990s in some local 
areas (Rothrock et al. 1999, p. 3471; Yu et al. 2004, p. 11). The 
length of the melt period affects sea ice cover and ice thickness 
(Hakkinen and Mellor 1990; Laxon et al. 2003, cited in Comiso 2005,

[[Page 1072]]

p. 50). Earlier melt onset and lengthening of the melt season result in 
decreased total ice cover at summer's end (Stroeve et al. 2005, p. 3). 
For 2002 through 2005, the NSIDC reported a trend of earlier onset of 
melt season in all four years; in 2005 the melt season arrived the 
earliest, occurring approximately 17 days before the mean melt onset 
date (NSIDC 2005, p. 6). The result of longer melt season is that the 
ice season is decreasing by as much as 8 days per year in the eastern 
Barents Sea, and by lesser amounts throughout much of the rest of the 
Arctic (Parkinson 2000a, p. 351). Comiso (2003, p. 3506) calculated an 
increase in the sea ice melt season of 10 to 17 days per decade. 
Subsequently, Comiso (2005, p. 50) included additional data from recent 
years and ice-free periods and determined that the length of the melt 
season is increasing at a rate of approximately 13.1 days per decade. 
Comiso (2005, p. 50) stated that the increasing melt periods were 
likely reasons for the current rapid decline of the perennial ice 
cover. Belchansky et al. (2004, p. 1) found that changes in January 
multiyear ice volume were significantly correlated with duration of the 
intervening melt season.
Projected Changes in Sea Ice Cover
    A number of climate models have been developed that project future 
conditions in the Arctic, as well as globally (ACIA 2005, p. 99; IPCC 
2001b, p. 471). All models predict continued Arctic warming and 
continued decreases in the Arctic sea ice cover in the 21st century 
(Johannessen 2004, p. 328) due to increasing global temperatures, 
although the level of increase varies between models. Comiso (2005, p. 
43) found that for each 1[deg]Centigrade (C) (1.6 [deg]F) increase in 
surface temperature (global average) there is a corresponding decrease 
in perennial sea ice cover of about 1.48 million km\2\ (.57 million 
mi\2\). Further, due to increased warming in the Arctic region, 
accepted models project almost no sea ice cover during summer in the 
Arctic Ocean by the end of the 21st century (Johannessen et al. 2004, 
p. 335). More recently, the NSIDC cautioned that the Arctic will be 
ice-free by 2060 if current warming trends continue (Serreze 2006, p. 
2).
    The winter maximum sea ice extent in 2005 and 2006 were both about 
6 percent lower than average values, indicating significant decline in 
the winter sea ice cover. In both cases, the observed surface 
temperatures were also significantly warmer and the onset of freeze-up 
was later than normal. In both years, onset of melt also happened early 
(Comiso in press). A continued decline would mean an advance to the 
north of the 0 [deg]C (32 [deg]F) isotherm temperature gradient, and a 
warmer ocean in the peripheral seas of the Arctic Ocean. This in turn 
may result in a further decline in winter ice cover.
    Predicted Arctic atmospheric and oceanographic changes for time 
periods through the year 2080 include increased air temperatures, 
increased precipitation and run-off, and reduced sea ice extent and 
duration (ACIA 2005, tables on pp. 470 and 476).
Effects of Sea Ice Habitat Change on Polar Bears
    Observed and predicted changes in sea ice cover, characteristics, 
and timing have profound effects on polar bears. Sea ice is a highly 
dynamic habitat with different types, forms, stages, and distributions 
of ice that all operate as a complex matrix in determining biological 
productivity and use by marine organisms, including polar bears and 
their primary prey base--ice seal species. Polar bear use of sea ice is 
not uniform. Their preferred habitat is the annual ice located over 
continental shelf and inter-island archipelagos that circle the Arctic 
basin. Ice seals demonstrate a similar preference to these ice 
habitats.
    Hudson Bay in Canada typifies change in the Arctic due to its 
southern location and occurrence on a divide between a warming and a 
cooling region (AMAP 2003, p. 22). It is therefore an ideal area to 
study the impacts of climate change. In addition, Hudson Bay has the 
most significant long-term time series of data on the ecology of polar 
bears and is the site of the first documented evidence of major and 
ongoing impacts to polar bears from sea ice changes. Many researchers 
over the past 40 years have predicted an array of impacts to polar 
bears from climatic change that include adverse effects on denning, 
food chain disruption, and prey availability (Budyko 1966; Vibe 1967, 
cited in Derocher et al. 2004, p. 164; Lentfer 1972, p. 169; Tynan and 
DeMaster 1997, p. 315; Stirling and Derocher 1993, pp. 241-244). 
Stirling and Derocher (1993, p. 240) first noted changes in polar bears 
in Western Hudson Bay such as declining body condition, lowered 
reproductive rates, and reduced cub survival; they attributed these 
changes to a changing ice environment. Subsequently, Stirling et al. 
(1999, p. 303) established a statistically significant link between 
climate warming in Western Hudson Bay, reduced ice presence, and 
observed declines in polar bear physical and reproductive parameters, 
including body condition (weight) and natality.
Increased Polar Bear Movements
    Polar bears are inefficient moving on land; they expend 
approximately twice the average energy use of other mammals when 
walking (Best 1982, p. 63; Hurst et al. 1982, p. 273). Sea ice 
circulation in the Arctic is clockwise, and polar bears tend to walk 
against this movement to maintain a position near preferred habitat 
within large geographical home ranges (Mauritzen et al. 2003a, p. 111). 
Currently, ice thickness is diminishing and there is increased 
transport of multi-year ice from the polar region. This increased rate 
and extent of ice movements requires additional efforts and energy 
expenditure for polar bears to maintain their position near preferred 
habitats (Derocher et al. 2004, p.167). Ferguson et al. (2001, p. 51) 
found that polar bears inhabiting areas of highly dynamic ice had much 
larger activity areas and movement rates compared to those bears 
inhabiting more stable, persistent ice habitat. Although polar bears 
are capable of living in areas of highly dynamic ice movement, they 
show inter-annual fidelity to the general location of preferred habitat 
(Mauritzen et al. 2003b, p. 122).
    As sea ice moves more quickly or becomes more fragmented, polar 
bears would likely use more energy to maintain contact with 
consolidated ice, because moving through highly fragmented sea ice is 
difficult and likely more energy-intensive than walking over 
consolidated sea ice (Derocher et al. 2004, p. 167). During summer 
periods the remaining ice in much of the central Arctic is now 
positioned away from more productive continental shelf waters and over 
much deeper, less productive waters, such as in the Beaufort and 
Chukchi Seas of Alaska. If the width of leads or extent of open water 
increases, the transit time for bears and the need to swim or to travel 
will increase (Derocher et al. 2004, p. 167). Derocher et al. (2004, p. 
167) suggests that as habitat patch sizes decrease, available food 
resources are likely to decline, resulting in reduced residency time 
and thus increased movement rates. The consequences of increased 
energetic costs to polar bears are reduced weight and condition and 
corresponding reduction in survival and recruitment rates (Derocher et 
al. 2004, p. 167).
    Additionally, as movement of sea ice increases and areas of 
unconsolidated ice increase, some bears will lose contact with the main 
body of ice and drift into unsuitable habitat from which

[[Page 1073]]

it may be difficult to return (Derocher et al. 2004, p. 167). This 
already occurs in some areas such as Southwest Greenland and offshore 
from the island of Newfoundland (Derocher et al. 2004, p. 167). 
Increased frequency of such events could negatively impact survival 
rates and contribute to population declines (Derocher et al. 2004, 
p.167).
Polar Bear Distribution Changes
    Recent studies indicate that polar bear distributions are changing 
and that these changes are strongly correlated to similar changes in 
sea ice and the ocean-ice system. Specifically, in Western Hudson Bay, 
breakup of the annual sea ice now occurs approximately 2.5 weeks 
earlier than it did 30 years ago (Stirling et al. 1999, p. 299). The 
earlier spring breakup was highly correlated with dates that female 
polar bears came ashore (Stirling et al. 1999, p. 299). Declining 
reproductive rates, subadult survival, and body mass (weights) have 
resulted from longer periods of fasting on land as a result of the 
progressively earlier breakup of the sea ice caused by an increase in 
spring temperatures (Stirling et al. 1999, p. 304; Derocher et al. 
2004, p. 165).
    Stirling et al. (1999, p. 304) reported a significant decline in 
the condition (weights) of both male and female adult polar bears since 
the 1980s in Western Hudson Bay, as well as lower natality rates. A 
positive relationship between body mass of females with cubs and 
survival of cubs was also established; survival of cubs of mothers in 
better condition (heavier) was greater than survival of cubs from 
lighter mothers (Derocher and Stirling 1996, p. 1248).
    Stirling et al. (1999, p. 304) cautioned that although downward 
trends in the size of the Western Hudson Bay population had not been 
detected, if trends in life history parameters continued downward 
``they will eventually have a detrimental effect on the ability of the 
population to sustain itself.'' Population declines have now been 
determined based on a recent analysis of an ongoing mark-recapture 
population study, and the earlier predictions of Stirling et al. (1999; 
p. 304) have been proven. Between 1987 and 2004, the number of polar 
bears in the Western Hudson Bay population declined from 1,194 to 935, 
a reduction of about 22 percent (Regehr et al. in prep.). Progressive 
declines in the condition and survival of cubs, subadults, and bears 20 
years of age and older, likely initiated the decline in the size of the 
Westen Hudson Bay population; these declines appear to have been 
initiated by progressively earlier sea ice breakup. Once the population 
began to decline, existing harvest rates of this population contributed 
to the reduction in the size of the population (Regehr et al. in 
prep.).
    Starting in the 1990s, Schliebe (unpublished data) has observed a 
trend of increasing use of coastal areas by polar bears during the fall 
open water period in the Southern Beaufort Sea. High numbers of bears 
were found to be using coastal areas during some years, where 
previously observations of polar bears on the coast were rare. The 
study period included record minimal ice conditions for the month of 
September in four of the six survey years. There was a significant 
relationship between the mean distance from the coast to the edge of 
pack ice and the numbers of bears observed on the coast. As the 
distance to the edge of the ice increased, the number of bears near 
shore increased. Conversely, as ice advanced toward shore, the number 
of bears near shore decreased. These results suggest that environmental 
factors, possibly similar to those observed in Western Hudson Bay, are 
influencing the distribution of polar bears in the southern Beaufort 
Sea. They also suggest that increased polar bear use of coastal areas 
may continue if the summer retreat of the sea ice continues to receed 
in the future as predicted (Serreze et al. 2000, p. 159; Serreze and 
Barry 2005).
    Gleason et al. (2006, p. 1) also found a shift in polar bear 
distributions in the southern Beaufort Sea. Their study evaluated polar 
bear distribution during three periods (1979 to 1986, 1987 to 1996, and 
1997 to 2005), and found that the September distribution of polar bears 
was primarily associated with offshore sea ice during the earlier two 
periods, but land and open water during the later period. These 
findings coincide with the lack of pack ice (concentrations of greater 
than 50 percent) caused by a retraction of ice in the study area during 
the latter period (Stroeve et al. 2005, p. 2; Comiso 2002 in Comiso 
2005, p. 46; Comiso 2003, p. 3509; Comiso 2005, p. 52).
    The findings of Gleason et al. (2006 p. 1) are consistent with 
those reported by Schliebe et al. (2006b, p. 559), and confirm an 
increasing trend in use of coastal areas by polar bears in the southern 
Beaufort Sea in recent years and a decline in ice habitat near shore. 
The proximate causes for changes in polar bear distribution are thought 
to be (1) retraction of pack ice far to the north for greater periods 
of time in the fall and (2) later freeze-up of coastal waters.
    Other polar bear populations exhibiting distribution changes with 
larger numbers of bears onshore include the Chukchi Sea (Kochnev 2006, 
p. 162), Baffin Bay, Davis Strait, Foxe Basin, and Hudson Bay 
populations (Stirling and Parkinson 2006). Stirling and Parkinson 
(2006, p. 261-275) provide an analysis of pack ice and distribution 
changes for the Baffin Bay, Davis Strait, Foxe Basin, and Hudson Bay 
populations. They indicate that earlier sea ice breakup will likely 
result in longer periods of fasting for polar bears during the extended 
open-water season and this is why more polar bears have been observed 
near communities and hunting camps in recent years. Distribution 
changes of polar bears have been noted during a similar period of time 
for the northern coast of Chukotka (Kochnev 2006, p. 162) and on 
Wrangel Island, Russia (Kochnev 2006, p. 162; N. Ovsyanikov, pers. 
comm.). The relationship between the maximum number of polar bears, the 
number of dead walruses, quantity of accessible food, and the distance 
of the ice-edge from Wrangel Island was evaluated. The regression 
analysis revealed that the strongest correlation was between bear 
numbers and distance to the ice-edge (Kochnev 2006, p. 162).
    In Baffin Bay, traditional Inuit knowledge studies and anecdotal 
reports indicate in many areas that greater numbers of bears are being 
encountered on land during the summer and fall open-water seasons. 
Interviews with elders and senior hunters in three communities in 
Nunavut, Canada, revealed that most respondents (83 percent) believed 
that the population of polar bears had increased. The increase was 
attributed to more bears seen near communities, cabins, and camps, and 
hunters encountering bear sign in areas not previously used by bears. 
Some people interviewed noted that these observations could reflect a 
change in bear behavior rather than an increase in population.
    Stirling and Parkinson (2006, p. 263) evaluated sea ice conditions 
and distribution of polar bears in five populations in eastern Canada: 
Western Hudson Bay, Eastern Hudson Bay, Baffin Bay, Foxe Basin, and 
Davis Strait. Their analysis of satellite imagery beginning in the 
1970s indicates that the sea ice is breaking up at progressively 
earlier dates, so that bears must fast for longer periods of time 
during the open water season. Stirling and Parkinson (2006, pp. 271-
272) point out that long-term data on population size and body 
condition of bears from the Western Hudson Bay, and population and 
harvest data from the Baffin Bay population indicate that these 
populations are declining or likely to be declining. The authors 
indicate that as

[[Page 1074]]

bears in these populations become more nutritionally stressed, the 
numbers of animals will decline and the declines will probably be 
significant. Based on the recent findings of Holland et al. (2006) 
these events are predicted to occur within the foreseeable future as 
defined in this rule (Stirling, pers. comm. 2006).
    Seasonal polar bear distribution changes noted above and the 
negative effect of prolonged use of terrestrial habita