[Federal Register Volume 76, Number 28 (Thursday, February 10, 2011)]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-2400]
February 10, 2011
Department of the Interior
Fish and Wildlife Service
50 CFR Part 17
Endangered and Threatened Wildlife and Plants; 12-Month Finding on a
Petition to List the Pacific Walrus as Endangered or Threatened;
Federal Register / Vol. 76, No. 28 / Thursday, February 10, 2011 /
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R7-ES-2009-0051; MO 92210-0-0008-B2]
Endangered and Threatened Wildlife and Plants; 12-Month Finding
on a Petition to List the Pacific Walrus as Endangered or Threatened
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 12-month petition finding.
SUMMARY: We, the U.S. Fish and Wildlife Service, announce a 12-month
finding on a petition to list the Pacific walrus (Odobenus rosmarus
divergens) as endangered or threatened and to designate critical
habitat under the Endangered Species Act of 1973, as amended. After
review of all the available scientific and commercial information, we
find that listing the Pacific walrus as endangered or threatened is
warranted. Currently, however, listing the Pacific walrus is precluded
by higher priority actions to amend the Lists of Endangered and
Threatened Wildlife and Plants. Upon publication of this 12-month
petition finding, we will add Pacific walrus to our candidate species
list. We will develop a proposed rule to list the Pacific walrus as our
priorities allow. We will make any determination on critical habitat
during development of the proposed listing rule. Consistent with
section 4(b)(3)(C)(iii) of the Endangered Species Act, we will review
the status of the Pacific walrus through our annual Candidate Notice of
DATES: The finding announced in this document was made on February 10,
ADDRESSES: This finding and supporting documentation are available on
the Internet at http://www.regulations.gov at Docket Number FWS-R7-ES-
2009-0051. A range map of the three walrus subspecies and a more
detailed map of the Pacific walrus range are available at the following
Web site: http://alaska.fws.gov/fisheries/mmm/walrus/wmain.htm.
Supporting documentation we used in preparing this finding is available
for public inspection, by appointment, during normal business hours at
the U.S. Fish and Wildlife Service, Alaska Regional Office, 1011 East
Tudor Road, Anchorage, AK 99503. Please submit any new information,
materials, comments, or questions concerning this finding to the above
FOR FURTHER INFORMATION CONTACT: James MacCracken, Marine Mammals
Management, Alaska Regional Office (see ADDRESSES); by telephone: 800-
362-5148; or by facsimile: 907-786-3816. If you use a
telecommunications device for the deaf (TDD), please call the Federal
Information Relay Service (FIRS) at 800-877-8339.
Section 4(b)(3)(B) of the Endangered Species Act of 1973, as
amended (Act) (16 U.S.C. 1531 et seq.), requires that, for any petition
to revise the Federal Lists of Endangered and Threatened Wildlife and
Plants that contains substantial scientific or commercial information
that listing the species may be warranted, we make a finding within 12
months of the date of receipt of the petition. In this finding, we will
determine whether the petitioned action is: (a) Not warranted, (b)
warranted, or (c) warranted, but the immediate proposal of a regulation
implementing the petitioned action is precluded by other pending
proposals to determine whether species are endangered or threatened,
and expeditious progress is being made to add or remove qualified
species from the Federal Lists of Endangered and Threatened Wildlife
and Plants. Section 4(b)(3)(C) of the Act requires that we treat a
petition for which the requested action is found to be warranted but
precluded as though resubmitted on the date of such finding, that is,
requiring a subsequent finding to be made within 12 months. We must
publish these 12-month findings in the Federal Register.
Previous Federal Actions
On February 8, 2008, we received a petition dated February 7, 2008,
from the Center for Biological Diversity, requesting that the Pacific
walrus be listed as endangered or threatened under the Act and that
critical habitat be designated. The petition included supporting
information regarding the species' ecology and habitat use patterns,
and predicted changes in sea-ice habitats and ocean conditions that may
impact the Pacific walrus. We acknowledged receipt of the petition in a
letter to the Center for Biological Diversity, dated April 9, 2008. In
that letter, we stated that an emergency listing was not warranted and
that all remaining available funds in the listing program for Fiscal
Year (FY) 2008 had already been allocated to the U.S. Fish and Wildlife
Service's (Service) highest priority listing actions and that no
listing funds were available to further evaluate the Pacific walrus
petition in FY 2008.
On December 3, 2008, the Center for Biological Diversity filed a
complaint in U.S. District Court for the District of Alaska for
declaratory judgment and injunctive relief challenging the failure of
the Service to make a 90-day finding on their petition to list the
Pacific walrus, pursuant to section 4(b)(3) of the Endangered Species
Act, 16 U.S.C. 1533(b)(3), and the Administrative Procedure Act, 5
U.S.C. 706(1). On May 18, 2009, a settlement agreement was approved in
the case of Center for Biological Diversity v. U.S. Fish and Wildlife
Service, et al. (3:08-cv-00265-JWS), requiring us to submit our 90-day
finding on the petition to the Federal Register by September 10, 2009.
On September 10, 2009, we made our 90-day finding that the petition
presented substantial scientific information indicating that listing
the Pacific walrus may be warranted (74 FR 46548). On August 30, 2010,
the Court approved an amended settlement agreement requiring us to
submit our 12-month finding to the Federal Register by January 31,
2011. This notice constitutes the 12-month finding on the February 7,
2008, petition to list the Pacific walrus as endangered or threatened.
This 12-month finding is based on our consideration and evaluation
of the best scientific and commercial information available. We
reviewed the information provided in the petition submitted to the
Service by the Center for Biological Diversity, information available
in our files, and other available published and unpublished
information. Additionally, in response to our Federal Register notice
of September 10, 2009, requesting information from the public, as well
as our September 10, 2010 press release, and other outreach efforts
requesting new information from the public, we received roughly 30,000
submissions, which we have considered in making this finding, including
information from the U.S. Marine Mammal Commission, the State of
Alaska, the Alaska North Slope Borough, the Eskimo Walrus Commission,
the Humane Society of the United States, the Center for Biological
Diversity, the American Petroleum Institute, and many interested
citizens. We also consulted with recognized Pacific walrus experts and
Federal, State, and Tribal agencies.
Taxonomy and Species Delineation
The walrus (Odobenus rosmarus) is the only living representative of
the family Odobenidae, a group of marine carnivores that was highly
the late Miocene and early Pliocene (Kohno 2006, pp. 416-419; Harington
2008, p. 26). Fossil evidence suggests that the genus evolved in the
North Pacific Ocean and dispersed throughout the Arctic Ocean and North
Atlantic during interglacial phases of the Pleistocene (Harington and
Beard 1992, pp. 311-319; Dyke et al. 1999, p. 60; Harington 2008, p.
Three modern subspecies of walruses are generally recognized
(Wozencraft 2005, p. 525; Integrated Taxonomic Information System,
2010, p. 1): The Atlantic walrus (O. r. rosmarus), which ranges from
the central Canadian Arctic eastward to the Kara Sea (Reeves 1978, pp.
2-20); the Pacific walrus (O. r. divergens), which ranges across the
Bering and Chukchi Seas (Fay 1982, pp. 7-21); and the Laptev walrus (O.
r. laptevi), which is represented by a small, geographically isolated
population of walruses in the Laptev Sea (Heptner et al. 1976, p. 34;
Vishnevskaia and Bychkov 1990, pp. 155-176; Andersen et al. 1998, p.
1323; Wozencraft 2005, p. 595; Jefferson et al. 2008, p. 376). Atlantic
and Pacific walruses are genetically and morphologically distinct from
each other (Cronin et al. 1994, p. 1035), likely as a result of range
fragmentation and differentiation during glacial phases of extensive
Arctic sea-ice cover (Harington 2008, p. 27). Although geographically
isolated and ecologically distinct, walruses from the Laptev Sea appear
to be more closely related to Pacific walruses (Lindqvist et al. 2009,
Pacific walruses are ecologically distinct from other walrus
populations, primarily because they undergo significant seasonal
migrations between the Bering and the Chukchi Seas and rely principally
on broken pack ice habitat to access offshore breeding and feeding
areas (Fay 1982, p. 279) (see Species Distribution, below). In
contrast, Atlantic walruses, which are represented by several small
discrete groups of animals distributed from the central Canadian Arctic
eastward to the Kara Sea, exhibit smaller seasonal movements and feed
primarily in coastal areas because the continental shelf is narrow over
much of their range. The majority of productive feeding areas used by
Atlantic walruses are accessible from the coast, and all age classes
and gender groups use terrestrial haulouts during ice-free seasons
(Born et al. 2003, p. 356; COSEWIC 2006, p. 15; Laidre et al. 2008, pp.
The Pacific walrus is generally considered a single population,
although some heterogeneity has been documented. Jay et al. (2008, p.
938) found some differences in the ratio of trace elements in the teeth
of Pacific walruses sampled in winter from two breeding areas
(southeast Bering Sea and St. Lawrence Island), suggesting that the
sampled animals had a history of feeding in different regions. Scribner
et al. (1997, p. 180), however, found no difference in mitochondrial
and nuclear DNA among Pacific walruses sampled from different breeding
areas. Pacific walruses are identified and managed in the United States
and the Russian Federation (Russia) as a single population (Service
2010, p. 1).
Walruses are readily distinguished from other Arctic pinnipeds
(aquatic carnivorous mammals with all four limbs modified into
flippers, this group includes seals, sea lions, and walruses) by their
enlarged upper canine teeth, which form prominent tusks. The family
name Odobenidae (tooth walker), is based on observations of walruses
using their tusks to pull themselves out of the water. Males, which
have relatively larger tusks than females, also tend to have broader
skulls (Fay 1982, pp. 104-108). Walrus tusks are used as offensive and
defensive weapons (Kastelein 2002, p. 1298). Adult males use their
tusks in threat displays and fighting to establish dominance during
mating (Fay et al. 1984, p. 93), and animals of both sexes use threat
displays to establish and defend positions on land or ice haulouts (Fay
1982, pp. 134-138). Walruses also use their tusks to anchor themselves
to ice floes when resting in the water during inclement weather (Fay
1982, pp. 134-138; Kastelein 2002, p. 1298).
The Pacific walrus is the largest pinniped species in the Arctic.
At birth, calves are approximately 65 kilograms (kg) (143 pounds (lb))
and 113 centimeters (cm) (44.5 inches (in)) long (Fay 1982, p. 32).
After the first 7 years of life, the growth rate of female walruses
declines rapidly, and they reach a maximum body size by approximately
10 years of age. Adult females can reach lengths of up to 3 meters (m)
(9.8 feet (ft)) and weigh up to 1,100 kg (2,425 lb). Male walrus tend
to grow faster and for a longer period of time than females. They
usually do not reach full adult body size until they are 15 to 16 years
of age. Adult males can reach lengths of 3.5 m (11.5 ft) and can weigh
more than 2,000 kg (4,409 lb) (Fay 1982, p. 33).
Walruses are social and gregarious animals. They tend to travel in
groups and haul out of the water to rest on ice or land in densely
packed groups. On land or ice, in any season, walruses tend to lie in
close physical contact with each other. Young animals often lie on top
of adults. Group size can range from a few individuals up to several
thousand animals (Gilbert 1999, p. 80; Kastelein 2002, p. 1298;
Jefferson et al. 2008, p. 378). At any time of the year, when groups
are disturbed, stampedes from a haulout can result in injuries and
mortalities. Calves and young animals are particularly vulnerable to
trampling injuries (Fay 1980, pp. 227-227; Fay and Kelly 1980, p. 226).
The reaction of walruses to disturbance ranges from no reaction to
escape into the water, depending on the circumstances (Fay et al. 1984,
pp. 13-14). Many factors play into the severity of the response,
including the age and sex of the animals, the size and location of the
group (on ice, in water, on land), their distance from the disturbance,
and the nature and intensity of the disturbance (Fay et al. 1984, pp.
14, 114-119). Females with calves appear to be most sensitive to
disturbance, and animals on shore are more sensitive than those on ice
(Fay et al. 1984, p. 114). A fright response caused by disturbance can
cause stampedes on a haulout, resulting in injuries and mortalities
(Fay and Kelly 1980, pp. 241-244).
Mating occurs primarily in January and February in broken pack ice
habitat in the Bering Sea. Breeding bulls follow herds of females and
compete for access to groups of females hauled out onto sea ice (Fay
1982, pp. 193-194). Males perform visual and acoustical displays in the
water to attract females and defend a breeding territory. Subdominant
males remain on the periphery of these aggregations and apparently do
not display. Intruders into display areas are met with threat displays
and physical attacks. Individual females leave the resting herd to join
a male in the water where copulation occurs (Fay et al. 1984, pp. 89-
99; Sjare and Stirling 1996, p. 900). Gestation lasts 15 to 16 months
(Fay 1982, p. 197) and pregnancies are spaced at least 2 years apart
(Fay 1982, p. 206). Calving occurs on sea ice, most typically in May,
before the northward spring migration (Fay 1982, pp. 199-200). Mothers
and newborn calves stay mostly on ice floes during the first few weeks
of life (Fay et al. 1984, p. 12).
The social bond between the mother and calf is very strong, and it
is unusual for a cow to become separated from her calf (Fay 1982, p.
203). The calf normally remains with its mother for at least 2 years,
sometimes longer, if not supplanted by a new calf (Fay 1982, pp. 206-
211). After separation from their
mother, young females tend to remain with groups of adult females,
whereas young males gradually separate from the females and begin to
associate with groups of other males. Individual social status appears
to be based on a combination of body size, tusk size, and
aggressiveness. Individuals do not necessarily associate with the same
group of animals and must continually reaffirm their social status in
each new aggregation (Fay 1982, p. 135; NAMMCO 2004, p. 43).
Pacific walruses range across the shallow continental shelf waters
of the northern Bering Sea and Chukchi Sea, occasionally ranging into
the East Siberian Sea and Beaufort Sea (Fay 1982, pp. 7-21; Figure 1 in
Garlich-Miller et al. 2011). Waters deeper than 100 m (328 ft) and the
extent of the pack ice are factors that limit distribution to the north
(Fay 1982, p. 23). Walruses are rarely spotted south of the Alaska
Peninsula and Aleutian archipelago; however, migrant animals (mostly
males) are occasionally reported in the North Pacific (Service 2010,
Pacific walruses are highly mobile, and their distribution varies
markedly in response to seasonal and interannual variations in sea-ice
cover. During the January to March breeding season, walruses congregate
in the Bering Sea pack ice in areas where open leads (fractures in sea
ice caused by wind drift or ocean currents), polynyas (enclosed areas
of unfrozen water surrounded by ice) or thin ice allow access to water
(Fay 1982, p. 21; Fay et al. 1984, pp. 89-99). The specific location of
winter breeding aggregations varies annually depending upon the
distribution and extent of ice. Breeding aggregations have been
reported southwest of St. Lawrence Island, Alaska; south of Nunivak
Island, Alaska; and south of the Chukotka Peninsula in the Gulf of
Anadyr, Russia (Fay 1982, p. 21; Mymrin et al. 1990, pp. 105-113;
Figure 1 in Garlich-Miller et al. 2011).
In spring, as the Bering Sea pack ice deteriorates, most of the
population migrates northward through the Bering Strait to summer
feeding areas over the continental shelf in the Chukchi Sea. However,
several thousand animals, primarily adult males, remain in the Bering
Sea during the summer months, foraging from coastal haulouts in the
Gulf of Anadyr, Russia, and in Bristol Bay, Alaska (Figure 1 in
Garlich-Miller et al. 2011).
Summer distributions (both males and females) in the Chukchi Sea
vary annually, depending upon the extent of sea ice. When broken sea
ice is abundant, walruses are typically found in patchy aggregations
over continental shelf waters. Individual groups may range from less
than 10 to more than 1,000 animals (Gilbert 1999, pp. 75-84; Ray et al.
2006, p. 405). Summer concentrations have been reported in loose pack
ice off the northwestern coast of Alaska, between Icy Cape and Point
Barrow, and along the coast of Chukotka, Russia, as far west as Wrangel
Island (Fay 1982, pp. 16-17; Gilbert et al. 1992, pp. 1-33; Belikov et
al. 1996, pp. 267-269). In years of low ice concentrations in the
Chukchi Sea, some animals range east of Point Barrow into the Beaufort
Sea; walruses have also been observed in the Eastern Siberian Sea in
late summer (Fay 1982, pp. 16-17; Belikov et al. 1996, pp. 267-269).
The pack ice of the Chukchi Sea usually reaches its minimum extent in
September. In years when the sea ice retreats north beyond the
continental shelf, walruses congregate in large numbers (up to several
tens of thousands of animals in some locations) at terrestrial haulouts
on Wrangel Island and other sites along the northern coast of the
Chukotka Peninsula, Russia, and northwestern Alaska (Fay 1982, p. 17;
Belikov et al. 1996, pp. 267-269; Kochnev 2004, pp. 284-288; Ovsyanikov
et al. 2007, pp. 1-4; Kavry et al. 2008, pp. 248-251).
In late September and October, walruses that summered in the
Chukchi Sea typically begin moving south in advance of the developing
sea ice. Satellite telemetry data indicate that male walruses that
summered at coastal haulouts in the Bering Sea also begin to move
northward towards winter breeding areas in November (Jay and Hills
2005, p. 197). The male walruses' northward movement appears to be
driven primarily by the presence of females at that time of year
(Freitas et al. 2009, pp. 248-260).
Foraging and Prey
Walruses consume mostly benthic (region at the bottom of a body of
water) invertebrates and are highly adapted to obtain bivalves (Fay
1982, p. 139; Bowen and Siniff 1999, p. 457; Born et al. 2003, p. 348;
Dehn et al. 2007, p. 176; Boveng et al. 2008, pp. 17-19; Sheffield and
Grebmeier 2009, pp. 766-767). Fish and other vertebrates have
occasionally been found in their stomachs (Fay 1982, p. 153; Sheffield
and Grebmeier 2009, p. 767). Walruses root in the bottom sediment with
their muzzles and use their whiskers to locate prey items. They use
their fore-flippers, nose, and jets of water to extract prey buried up
to 32 cm (12.6 in) (Fay 1982, p. 163; Oliver et al. 1983, p. 504;
Kastelein 2002, p. 1298; Levermann et al. 2003, p. 8). The foraging
behavior of walruses is thought to have a major impact on benthic
communities in the Bering and Chukchi Seas (Oliver et al. 1983, pp.
507-509; Klaus et al. 1990, p. 480). Ray et al. (2006, pp. 411-413)
estimate that walruses consume approximately 3 million metric tons
(3,307 tons) of benthic biomass annually, and that the area affected by
walrus foraging is in the order of thousands of square kilometers (sq
km) (thousands of square miles (sq mi)) annually. Consequently,
walruses play a major role in benthic ecosystem structure and function,
which Ray et al. (2006, p. 415) suggested increased nutrient flux and
The earliest studies of food habits were based on examination of
stomachs from walruses killed by hunters. These reports indicated that
walruses were primarily feeding on bivalves (clams), and that non-
bivalve prey was only incidentally ingested (Fay 1982, p. 145;
Sheffield et al. 2001, p. 311). However, these early studies did not
take into account the differential rate of digestion of prey items
(Sheffield et al. 2001, p. 311). Additional research indicates that
stomach contents include over 100 taxa of benthic invertebrates from
all major phyla (Fay 1982, p. 145; Sheffield and Grebmeier 2009, p.
764), and while bivalves remain the primary component, walruses are not
adapted to a diet solely of clams. Other prey items have similar
energetic benefits (Wacasey and Atkinson 1987, pp. 245-247). Based on
analysis of the contents from fresh stomachs of Pacific walruses
collected between 1975 and 1985 in the Bering Sea and Chukchi Sea, prey
consumption likely reflects benthic invertebrate composition (Sheffield
and Grebmeier 2009, pp. 764-768). Of the large number of different
types of prey, statistically significant differences between males and
females from the Bering Sea were found in the occurrence of only two
prey items, and there were no statistically significant differences in
results for males and females from the Chukchi Sea (Sheffield and
Grebmeier 2009, pp. 765). Although these data are for Pacific walrus
stomachs collected 25-35 years ago, we have no reason to believe there
has been a change in the general pattern of prey use described here.
Walruses typically swallow invertebrates without shells in their
entirety (Fay 1982, p. 165). Walruses remove the soft parts of mollusks
from their shells by suction, and discard the shells (Fay 1982, pp.
166-167). Born et al. (2003, p. 348) reported that Atlantic
walruses consumed an average of 53.2 bivalves (range 34 to 89) per
dive. Based on caloric need and observations of captive walruses,
walruses require approximately 29 to 74 kg (64 to 174 lbs) of food per
day (Fay 1982, p. 160). Adult males forage little during the breeding
period (Fay 1982, pp. 142, 159-161; Ray et al. 2006, p. 411), while
lactating females may eat two to three times that of nonpregant,
nonlactating females (Fay 1982, p.159). Calves up to 1 year of age
depend primarily on their mother's milk (Fay 1982, p. 138) and are
gradually weaned in their second year (Fisher and Stewart 1997, pp.
Although walruses are capable of diving to depths of more than 250
m (820 ft) (Born et al. 2005, p. 30), they usually forage in waters of
80 m (262 ft) or less (Fay and Burns 1988, p. 239; Born et al. 2003, p.
348; Kovacs and Lydersen 2008, p. 138), presumably because of higher
productivity of their benthic foods in shallow waters (Fay and Burns
1988, pp. 239-240; Carey 1991, p. 869; Jay et al. 2001, p. 621;
Grebmeier et al. 2006b, pp. 334-346; Grebmeier et al. 2006a, p. 1461).
Walruses make foraging trips from land or ice haulouts that range from
a few hours up to several days and up to 100 kilometers (km) (60 miles
(mi)) (Jay et al. 2001, p. 626; Born et al. 2003, p. 349; Ray et al.
2006, p. 406; Udevitz et al. 2009, p. 1122). Walruses tend to make
shorter and more frequent foraging trips when sea ice is used as a
foraging platform compared to terrestrial haulouts (Udevitz et al.
2009, p. 1122). Satellite telemetry data for walruses in the Bering Sea
in April of 2004, 2005, and 2006 showed they spent an average of 46
hours in the water between resting bouts on ice, which averaged 9 hours
(Udevitz et al. 2009, p. 1122). Because females and young travel with
the retreating pack ice in the spring and summer, they are passively
transported northward over feeding grounds across the continental
shelves of the Bering and Chukchi Seas. Male walruses appear to have
greater endurance than females, with foraging excursions from land
haulouts that can last up to 142 hours (about 6 days) (Jay et al. 2001,
The Pacific walrus is an ice-dependent species that relies on sea
ice for many aspects of its life history. Unlike other pinnipeds,
walruses are not adapted for a pelagic existence and must haul out on
ice or land regularly. Floating pack ice serves as a substrate for
resting between feeding bouts (Ray et al. 2006, p. 404), breeding
behavior (Fay et al. 1984, pp. 89-99), giving birth (Fay 1982, p. 199),
and nursing and care of young (Kelly 2001, pp. 43-55). Sea ice provides
access to offshore feeding areas over the continental shelf of the
Bering and Chukchi Seas, passive transportation to new feeding areas
(Richard 1990, p. 21; Ray et al. 2006, pp. 403-419), and isolation from
terrestrial predators (Richard 1990, p. 23; Kochnev 2004, p. 286;
Ovsyanikov et al. 2007, pp. 1-4). Sea ice provides an extensive
substrate upon which the risk of predation and hunting is greatly
reduced (Kelly 2001, pp. 43-55; Fay 1982, p. 26).
Sea ice in the Northern Hemisphere is comprised of first-year sea
ice that formed in the most recent autumn-winter period, and multi-year
ice that has survived at least one summer melt season. Sea-ice habitats
for walruses include openings or leads that provide access to the water
and to food resources. Walruses generally do not use multi-year ice or
highly compacted first-year ice in which there is an absence of
persistent leads or polynyas (Richard 1990, p. 21). Expansive areas of
heavy ice cover are thought to play a restrictive role in walrus
distributions across the Arctic and serve as a barrier to the mixing of
populations (Fay 1982, p. 23; Dyke et al. 1999, pp. 161-163; Harington
2008, p. 35). Walruses generally do not occur farther south than the
maximum extent of the winter pack ice, possibly due to their reliance
on sea ice for breeding and rearing young (Fay et al. 1984, pp. 89-99)
and isolation from terrestrial predators (Kochnev 2004, p. 286;
Ovsyanikov et al. 2007, pp. 1-4), or because of the higher densities of
benthic invertebrates in northern waters (Grebmeier et al. 2006a, pp.
Walruses generally occupy first-year ice that is greater than 20 cm
(7.9 in) thick and are not found in areas of extensive, unbroken ice
(Fay 1982, pp. 21, 26; Richard 1990, p. 23). Thus, in winter they
concentrate in areas of broken pack ice associated with divergent ice
flow or along the margins of persistent polynyas (Burns et al. 1981,
pp. 781-797; Fay et al. 1984, pp. 89-99; Richard 1990, p. 23) in areas
with abundant food resources (Ray et al. 2006, p. 406). Females with
young generally spend the summer months in pack ice habitats of the
Chukchi Sea, where they feed intensively between bouts of resting and
suckling their young. Some authors have suggested that the size and
topography of individual ice floes are important features in the
selection of ice haulouts, noting that some animals have been observed
returning to the same ice floe between feeding bouts (Ray et al. 2006,
p. 406). However, it has also been noted that walruses can and will
exploit a fairly broad range of ice types and ice concentrations in
order to stay in preferred foraging or breeding areas (Freitas et al.
2009, p. 247; Jay et al. 2010a, p. 300). Walruses tend to make shorter
foraging excursions when they are using sea ice rather than land
haulouts (Udevitz et al. 2009, p. 1122), presumably because it is more
energetically efficient for them to haulout on ice near productive
feeding areas than forage from shore. Fay (1982, p. 25) notes that
several authors reported that when walruses had the choice of ice or
land for a resting place, ice was always selected.
Terrestrial Habitats (Coastal Haulouts)
When suitable sea ice is not available, walruses haul out on land
to rest. A wide variety of substrates, ranging from sand to boulders,
are used. Isolated islands, points, spits, and headlands are occupied
most frequently. The primary consideration for a terrestrial haulout
site appears to be isolation from disturbances and predators, although
social factors, learned behavior, protection from strong winds and
surf, and proximity to food resources also likely influence the choice
of terrestrial haulout sites (Richard 1990, p. 23). Walruses tend to
use established haulout sites repeatedly and exhibit some degree of
fidelity to these sites (Jay and Hills 2005, pp. 192-202), although the
use of coastal haulouts appears to fluctuate over time, possibly due to
localized prey depletion (Garlich-Miller and Jay 2000, pp. 58-65).
Human disturbance is also thought to influence the choice of haulout
sites; many historic haulouts in the Bering Sea were abandoned in the
early 1900s when the Pacific walrus population was subjected to high
levels of exploitation (Fay 1982, p. 26; Fay et al. 1984, p. 231).
Adult male walruses use land-based haulouts more than females or
young, and consequently, have a greater geographical distribution
through the ice-free season. Many adult males remain in the Bering Sea
throughout the ice-free season, making foraging trips from coastal
haulouts in Bristol Bay, Alaska, and the Gulf of Anadyr, Russia (Figure
1 in Garlich-Miller et al. 2011), while females and juvenile animals
generally stay with the drifting ice pack throughout the year (Fay
1982, pp. 8-19). Females with dependent young may prefer sea-ice
habitats because coastal haulouts pose greater risk from trampling
injuries and predation (Fay and Kelly 1980, pp. 226-245; Ovsyanikov et
al. 1994, p. 80; Kochnev
2004, pp. 285-286; Ovsyanikov et al. 2007, pp. 1-4; Kavry et al. 2008,
pp. 248-251; Mulcahy et al. 2009, p. 3). Females may also prefer sea-
ice habitats because they may have difficulty nourishing themselves
while caring for a young calf that has limited swimming range (Cooper
et al. 2006, p. 101; Jay and Fischbach 2008, p. 1).
The numbers of male walruses using coastal haulouts in the Bering
Sea during the summer months, and the relative uses of different
coastal haulout sites in the Bering Sea have varied over the past
century. Harvest records indicate that walrus herds were once common at
coastal haulouts along the Alaska Peninsula and the islands of northern
Bristol Bay (Fay et al. 1984, pp. 231-376). By the early 1950s, most of
the traditional haulout areas in the Southern Bering Sea had been
abandoned, presumably due to hunting pressure. During the 1950s and
1960s, Round Island was the only regularly used haulout in Bristol Bay,
Alaska. In 1960, the State of Alaska established the Walrus Islands
State Game Sanctuary, which closed Round Island to hunting. Peak counts
of walruses at Round Island increased from 1,000-2,000 animals in the
late 1950s (Frost et al. 1983, pp. 379) to more than 10,000 animals in
the early 1980s (Sell and Weiss, p. 12), but subsequently declined to
2,000-5,000 over the past decade (Sell and Weiss 2010, p. 12). General
observations indicate that declining walrus counts at Round Island may,
in part, reflect a redistribution of animals to other coastal sites in
the Bristol Bay region. For example, walruses have been observed
increasingly regularly at the Cape Seniavin haulout on the Alaska
Peninsula since the 1970s, and at Cape Peirce and Cape Newenham in
northwest Bristol Bay since the early 1980s (Jay and Hills 2005, p.
193; Figure 1 in Garlich-Miller et al. 2011).
Traditional male summer haulouts along the Bering Sea coast of
Russia include sites along the Kamchatka Peninsula, the Gulf of Anadyr
(most notably Rudder and Meechkin spits), and Arakamchechen Island
(Garlich-Miller and Jay 2000, pp. 58-65; Figure 1 in Garlich-Miller et
al. 2011). Several of the southernmost haulouts along the coast of
Kamchatka have not been occupied in recent years, and the number of
animals in the Gulf of Anadyr has also declined in recent years
(Kochnev 2005, p. 4). Factors influencing abundance at Bering Sea
haulouts are poorly understood, but may include changes in prey
densities near the haulouts, changes in population size, disturbance
levels, and changing seasonal distributions (Jay and Hills 2005, p.
198) (presumably mediated by sea-ice coverage or temperature).
Historically, coastal haulouts along the Arctic (Chukchi Sea) coast
have been used less consistently during the summer months than those in
the Bering Sea because of the presence of pack ice (a preferred
substrate) for much of the year in the Chukchi Sea. Since the mid-
1990s, reductions of summer sea ice coincided with a marked increase in
the use of coastal haulouts along the Chukchi sea coast of Russia
during the summer months (Kochnev 2004, pp. 284-288; Kavry et al. 2008,
pp. 248-251). Large, mixed (composed of various age and sex groups)
herds of walruses, up to several tens of thousands of animals, began to
use coastal haulouts on Wrangel Island, Russia in the early 1990s, and
several coastal haulouts along the northern Chukotka coastline of
Russia have emerged in recent years, likely as a result of reductions
in summer sea ice in the Chukchi Sea (Kochnev 2004, pp. 284-288;
Ovsyanikov et al. 2007, pp. 1-4; Kavry et al. 2008, p. 248-251; Figure
1 in Garlich-Miller et al. 2011).
In 2007, 2009, and 2010, walruses were also observed hauling out in
large numbers with mixed sex and age groups along the Chukchi Sea coast
of Alaska in late August, September, and October (Thomas et al. 2009,
p. 1; Service 2010, unpublished data). Monitoring studies conducted in
association with oil and gas exploration suggest that the use of
coastal haulouts along the Arctic coast of Alaska during the summer
months is dependent upon the availability of sea ice. For example, in
2006 and 2008, walruses foraging off the Chukchi Sea coast of Alaska
remained with the ice pack over the continental shelf during the months
of August, September, and October. However in 2007, 2009, and 2010, the
pack ice retreated beyond the continental shelf and large numbers of
walruses hauled out on land at several locations between Point Barrow
and Cape Lisburne, Alaska (Ireland et al. 2009, p. xvi; Thomas et al.
2009, p. 1; Service 2010, unpublished data; Figure 1 in Garlich-Miller
et al. 2011).
Transitory coastal haulouts have also been reported in late fall
(October-November) along the southern Chukchi Sea coast, coinciding
with the southern migration. Mixed herds of walruses frequently come to
shore to rest for a few days to weeks along the coast before continuing
on their migration to the Bering Sea. Cape Lisburne, Alaska, and Capes
Serdtse-Kamen' and Dezhnev, Russia, are the most consistently used
haulouts in the Chukchi Sea at this time of year (Garlich-Miller and
Jay 2000, pp. 58-67). Large mixed herds of walruses have also been
reported in late fall and early winter at coastal haulouts in the
northern Bering Sea at the Punuk Islands and Saint Lawrence Island,
Alaska; Big Diomede Island, Russia; and King Island, Alaska, prior to
the formation of sea ice in offshore breeding and feeding areas (Fay
and Kelly 1980, p. 226; Garlich-Miller and Jay 2000, pp. 58-67; Figure
1 in Garlich-Miller et al. 2011).
Walruses have the lowest rate of reproduction of any pinniped
species (Fay 1982, pp. 172-209). Although male walruses reach puberty
at 6-7 years of age, they are unlikely to successfully compete for
access to females until they reach full body size at 15 years of age or
older (Fay 1982, p. 33; Fay et al. 1984, p. 96). Female walruses attain
sexual maturity at 4-7 years of age (Fay 1982, pp. 172-209), and the
median age of first birth ranges from approximately 8 to 10 years of
age (Garlich-Miller et al. 2006, pp. 887-893). Because gestation lasts
15-16 months, it extends through the following breeding season and
thus, the minimum interval between successful births is 2 years.
Ovulation may also be suppressed until the calf is weaned, raising the
birth interval to 3 years or more (Garlich-Miller and Stewart 1999, p.
188). The age of sexual maturity and birth rates may be density-
dependent (Fay et al. 1989, pp. 1-16; Fay et al. 1997, pp. 537-565;
Garlich-Miller et al. 2006, pp. 892-893).
The low birth rate of walruses is offset in part by considerable
maternal investment in offspring (Fay et al. 1997, p. 550). Assumed
survival rates through the first year of life range from 0.5 to 0.9
(Fay et al. 1997, p. 550). Survival rates for juveniles through adults
(i.e., 4-20 years old) have been assumed to be as high as 0.96 to 0.99
per cent (DeMaster 1984, p. 78; Fay et al. 1997, p. 544), declining to
zero by 40 to 45 years (Chivers 1999, p. 240). Using published
estimates of survival and reproduction, Chivers (1999, pp. 239-247)
developed an individual age-based model of the Pacific walrus
population, which yielded a maximum population growth rate of 8
percent, but cautioned this should not be considered to be an estimate
of the maximum growth rate (Chivers 1999, p. 239). Thus, the 8 percent
figure remains theoretical because age-specific survival rates for
free-ranging walruses are poorly known.
Based on large sustained harvests in the 18th and 19th centuries,
Fay (1982, p. 241) speculated that the pre-
exploitation population was represented by a minimum of 200,000
animals. Since that time, population size is believed to have
fluctuated in response to varying levels of human exploitation. Large-
scale commercial harvests are believed to have reduced the population
to 50,000-100,000 animals in the mid-1950s (Fay et al. 1997, p. 539).
The population apparently increased rapidly in size during the 1960s
and 1970s in response to harvest regulations that limited the take of
females (Fay et al. 1989, p. 4). Between 1975 and 1990, visual aerial
surveys jointly conducted by the United States and Russia at 5-year
intervals produced population estimates ranging from 201,039 to
290,000. Efforts to survey the Pacific walrus population were suspended
by both countries after 1990, due to unresolved problems with survey
methods that produced population estimates with unknown bias and
unknown--but presumably large--variances that severely limited their
utility (Speckman et al. 2010, p. 3).
In 2006, a joint U.S.-Russian survey was conducted in the pack ice
of the Bering Sea, using thermal imaging systems to detect walruses
hauled out on sea ice and satellite transmitters to account for
walruses in the water (Speckman et al. 2010, p. 4). The number of
walruses within the surveyed area was estimated at 129,000, with 95-
percent confidence intervals of 55,000 to 507,000 individuals. This is
a minimum estimate, as weather conditions forced termination of the
survey before much of the southwest Bering Sea was surveyed; animals
were observed in that region as the surveyors returned to Anchorage,
Alaska. Table 1 provides a summary of survey results.
Table 1--Estimates of Pacific Walrus Population Size, 1975-2006.
Population size (with range
Year or confidence interval) \a\ Reference
1975................................... 214,687 (Udevitz et al. 2001, p. 614).
1980................................... 250,000-290,000 (Johnson et al. 1982, p. 3; Fedoseev 1984, p. 58).
1985................................... 242,366 (Udevitz et al. 2001, p. 614).
1990................................... 201,039 (Gilbert et al. 1992, p. 28).
2006................................... 129,000 (50,000-500,000) (Speckman et al. 2010).
\a\Due to differences in methods, comparisons of estimates across years (population trends) are not possible. Most estimates did not provide a range or
We acknowledge that these survey results suggest to some that the
walrus population may be declining; however, we do not believe the
survey methodologies support such a definitive conclusion. Resource
managers in Russia have concluded that the population has declined, and
accordingly, have reduced harvest quotas in recent years (Kochnev 2004,
p. 284; Kochnev 2005, p. 4; Kochnev, 2010, pers. comm.), based in part
on the lower abundance estimate generated from the 2006 survey results.
However, past survey results are not directly comparable among years
due to differences in survey methods, timing of surveys, segments of
the population surveyed, and incomplete coverage of areas where
walruses may have been present (Fay et al. 1997, p. 537); thus, these
results do not provide a basis for determining trends in population
size (Hills and Gilbert 1994, p. 203; Gilbert 1999, pp. 75-84). Whether
prior estimates are biased low or high is unknown, because of problems
with detecting individual animals on ice or land, and in open water,
and difficulties counting animals in large, dense groups (Speckman et
al. 2010, p. 33). In addition, no survey has ever been completed within
a timeframe that could account for the redistribution of individuals
(leading to double counting or undercounting), or before weather
conditions either delayed the effort or completely terminated the
survey before the entire area of potentially occupied habitat had been
covered (Speckman et al. 2010). Due to these general problems, as well
as seasonal differences among surveys (fall or spring) and
technological advancements that correct for some problems, we do not
believe the survey results provide a reliable basis for estimating a
Changes in the walrus population have also been investigated by
examining changes in biological parameters over time. Based on evidence
of changes in abundance, distributions, condition indices, and life-
history parameters, Fay et al. (1989, pp.1-16) and Fay et al. (1997,
pp. 537-565) concluded that the Pacific walrus population increased
greatly in size during the 1960s and 1970s, and postulated that the
population was approaching, or had exceeded, the carrying capacity of
its environment by the early 1980s. Harvest increased in the 1980s:
changes in the size, composition, and productivity of the sampled
walrus harvest in the Bering Strait Region of Alaska over this time
frame are consistent with this hypothesis (Garlich-Miller et al. 2006,
p. 892). Harvest levels declined sharply in the early 1990s, and
increased reproductive rates and earlier maturation in females
occurred, suggesting that density-dependent regulatory mechanisms had
been relaxed and the population was likely below carrying capacity
(Garlich-Miller et al. 2006, p. 893). However, Garlich-Miller et al.
(2006, pp. 892-893) also noted that there are no data concerning the
trend in abundance of the walrus population or the status of its prey
to verify this hypothesis, and that whether density-dependent changes
in life-history parameters might have been mediated by changes in
population abundance or changes in the carrying capacity of the
environment is unknown.
Summary of Information Pertaining to the Five Factors
Section 4 of the Act (16 U.S.C. 1533) and implementing regulations
(50 CFR part 424) set forth the procedures for adding species to,
removing species from, or reclassifying species on the Federal Lists of
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of
the Act, a species may be determined to be endangered or threatened
based on any of the following five factors:
(A) The present or threatened destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial, recreational, scientific, or
(C) Disease or predation;
(D) The inadequacy of existing regulatory mechanisms; or
(E) Other natural or manmade factors affecting its continued
In making this 12-month finding, we considered and evaluated the
best available scientific and commercial information. Information
pertaining to the Pacific walrus in relation to the five
factors provided in section 4(a)(1) of the Act is discussed below.
In considering what factors might constitute threats to a species,
we must look beyond the exposure of the species to a particular
stressor to evaluate whether the species may respond to that stressor
in a way that causes actual impacts to the species. If there is
exposure to a stressor and the species responds negatively, the
stressor may be a threat and we attempt to determine how significant a
threat it is. The threat is significant if it drives, or contributes
to, the risk of extinction of the species such that the species
warrants listing as endangered or threatened as those terms are defined
in the Act. However, the identification of stressors that could impact
a species negatively may not be sufficient to compel a finding that the
species warrants listing. The information must include evidence
sufficient to suggest that these stressors are operative threats that
act on the species to the point that the species meets the definition
of endangered or threatened under the Act. Also, because an individual
stressor may not be a threat by itself, but could be in conjunction
with one or more other stressors, our process includes considering the
combined effects of stressors.
To inform our analysis of threats to the Pacific walrus, we also
took into consideration the results of two Bayesian network modeling
efforts; one conducted by the Service (Garlich-Miller et al. 2011), and
the other conducted by the U.S. Geological Survey (USGS) (Jay et al.
2010b). Although quantitative, empirical data can be used in Bayesian
networks, when primarily qualitative data are available, such as for
the Pacific walrus, the models are well suited to formalizing and
quantifying the opinions of experts (Marcot et al. 2006, p. 3063).
Bayesian network models (also known as Bayesian belief networks,
reflecting the importance of expert opinion) graphically display the
relevant stressors, the interactions among stressors, and the
cumulative impact of those stressors as they are integrated through the
network. In general terms, the network is composed of input variables
that represent key environmental correlates (e.g., sea-ice loss,
harvest, shipping) and response variables, (e.g., population status).
Although we did not rely on the results of the Bayesian models as the
sole basis for our conclusions in this finding, the models corroborated
the results of our threats analysis. Results of the models are
presented in the five-factor analysis below, where pertinent.
Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range
The following potential stressors that may affect the habitat or
range of the Pacific walrus are discussed in this section: (1) Loss of
sea ice due to climate change; and (2) effects on prey species due to
ocean warming and ocean acidification.
Effects of Global Climate Change on Sea-Ice Habitats
The Pacific walrus depends on sea ice for several aspects of its
life history. This section describes recent observations and future
projections of sea-ice conditions in the Bering and Chukchi Seas
through the end of the 21st century. Following this presentation on the
changing ice dynamics, we examine how these changing ice conditions may
affect the Pacific walrus population.
The Arctic Ocean is covered primarily by a mix of multi-year sea
ice, whereas more southerly regions, such as the Bering Sea, are
seasonal ice zones where first-year ice is renewed every winter. The
observed and projected effects of global warming vary in different
parts of the world, and the Arctic and Antarctic regions are
increasingly recognized as being extremely vulnerable to current and
projected effects. For several decades, the surface air temperatures in
the Arctic have warmed at approximately twice the global rate
(Christensen et al. 2007, p. 904). The observed and projected effects
of climate change are most extreme during summer in northern high-
latitude regions, in large part due to the ice-albedo (reflective
property) feedback mechanism, in which melting of snow and sea ice
lowers surface reflectivity, thereby further increasing surface warming
from absorption of solar radiation.
Since 1979 (the beginning of the satellite record of sea-ice
conditions), there has been an overall reduction in the extent of
Arctic sea ice (Parkinson et al. 1999, p. 20837; Comiso 2002, p. 1956;
Stroeve et al. 2005, pp. 1-4; Comiso 2006, pp. 1-3; Meier et al. 2007,
p. 428; Stroeve et al. 2007, p. 1; Comiso et al. 2008, p. 1; Stroeve et
al. 2008, p. 13). Although the decline is a year-round trend, far
greater reductions have been noted in summer sea ice than in winter sea
ice. For example, from 1979 to 2009, the extent of September sea ice
seen Arctic wide has declined 11 percent per decade (Polyak et al.
2010, p. 1797). In recent years, the trend in Arctic sea-ice loss has
accelerated (Comiso et al. 2008, p. 1). In September 2007, the extent
of Arctic Ocean sea ice reached a record low, approximately 50 percent
lower than conditions in the 1950s through the 1970s, and 23 percent
below the previous record set in 2005 (Stroeve et al. 2008, p. 13).
Minimum sea-ice extent in 2010 was the third lowest in the satellite
record, behind 2007 and 2008 (second lowest), and most of this loss
occurred on the Pacific side of the Arctic Ocean.
Of long-term significance is the loss of over 40 percent of Arctic
multi-year sea ice over the last 5 years (Kwok et al. 2009, p. 1).
Since 2004, there has been a reversal in the volumetric and areal
contributions between first-year ice and multi-year ice in regards to
the total volume and area of the Arctic Ocean that they cover, with
first-year ice now predominating (Kwok et al. 2009, p. 16). Export of
ice through Fram Strait, together with the decline in multi-year ice
coverage, suggests that recently there has been near-zero replenishment
of multi-year ice (Kwok et al. 2009, p. 16). The area of the Arctic
Ocean covered by ice predominantly older than 5 years decreased by 56
percent between 1982 and 2007 (Polyak et al. 2010, p. 1759). Within the
central Arctic Ocean, old ice has declined by 88 percent, and ice that
is at least 9 years old has essentially disappeared (Markus et al.
2009, p. 13: Polyak et al. 2010, p. 1759). In addition, from 2005 to
2008 there was a thinning of 0.6 m (1.9 ft) in multi-year ice
thickness. It is likely that the rapid decline of sea ice in 2007 was
in part the result of thinner and lower coverage, of the multi-year ice
(Comiso et al. 2008, p. 6). It would take many years to restore the ice
thickness through annual growth, and the loss of multi-year ice makes
it unlikely that the age and thickness composition of the ice pack will
return to previous climatological conditions with continued global
warming. Further loss of sea ice will be a major driver of changes
across the Arctic over the next decades, especially in late summer and
autumn (NOAA 2010, p. 77503).
Due to asymmetric geography of the Arctic and the scale of weather
patterns, there is considerable regional variability in sea-ice cover
(Meier et al. 2007, p. 430), and although the early loss of summer sea
ice and volumetric ice loss in the Arctic applies directly to the
Chukchi Sea, it cannot be directly extrapolated to the seasonal ice
zone of the Bering Sea (NOAA 2010, p. 77503). The contrasts between the
two are dramatic: The Bering Sea is one of the most stable in terms of
sea ice, especially in the winter, and the Chukchi Sea has had some of
the most dramatic losses of summer sea ice
(Meier et al., p. 431). Below, we describe the sea-ice conditions in
the Bering and Chukchi Seas as they occur presently, as well as recent
trends and projections for the future.
In March and April, at maximal sea-ice extent, the Chukchi Sea is
typically completely frozen, and ice cover in the Bering Sea extends
southward to a latitude of approximately 58-60 degrees north (Boveng et
al. 2008, pp. 33-52). The Bering Sea spans the marginal sea-ice zone,
where ice gives way to water at the southern edge, and around the
peripheries of persistent polynyas. Sea ice in the Bering Sea is highly
dynamic and largely a wind-driven system (Sasaki and Minobe 2005, pp.
1-2). Ice cover is comprised of a variety of first-year ice
thicknesses, from young, very thin ice to first-year floes that may be
upwards of 1.0-m (3.3-ft) thick (Burns et al. 1980, p. 100; Zhang et
al. 2010, p. 1729). Depending on wind patterns, a variable (but
relatively minor) fraction of ice that drifts south through the Bering
Strait could be comprised of some thicker ice floes that originated in
the Chukchi and Beaufort Seas (Kozo et al. 1987, pp. 193-195).
Ice melt in the Bering Sea usually begins in late April and
accelerates in May, with the edge of the ice moving northward until it
passes through the Bering Strait, typically in June. The Bering Sea
remains ice free for the duration of the summer. Ice continues to
retreat northward through the Chukchi Sea until September, when minimal
sea-ice extent is reached.
Freeze-up begins in October, with the ice edge progressing
southward across the Chukchi Sea. The ice edge usually reaches the
Bering Strait in November and advances through the Strait in December.
The ice edge continues to move southward across the Bering Sea until
its maximal extent is reached in March. There is considerable year-to-
year variation in the timing and extent of ice retreat and formation
(Boveng et al. 2008, p. 37; Douglas 2010, p. 19).
Within various regions of the Arctic, there is substantial
variation in the monthly trends of sea ice (Meier et al. 2007, p. 431).
In the Bering Sea, statistically significant monthly reductions in the
extent of sea ice over the period 1979-2005 were documented for March
(-4.8 percent), October (-42.9 percent), and November (-20.3 percent),
although the overall annual decline (-1.9 percent) is not statistically
significant (Meier et al. 2007, p. 431). The Bering Sea declines were
greatest in October and November, the period of early freeze-up. In the
Chukchi Sea, statistically significant monthly reductions were also
documented for 1979 to 2005 for May (-0.19 percent), June (-4.3
percent), July (-6.7 percent), August (-15.4 percent), September (-26.3
percent), October (-18.6 percent), and November (-8.0 percent): The
overall annual reduction (-4.9 percent) is statistically significant
(Meier et al. 2007, p. 431). In essence, the Chukchi Sea has shown
declines in all months when it is not completely ice-covered, with
greatest declines in months of maximal melt and early freeze-up
(August, September, and October).
During the period 1979-2006, the September sea-ice extent in the
Chukchi Sea decreased by 26 percent per decade (Douglas 2010, p. 2). In
recent years, sea ice typically has retreated from continental shelf
regions of the Chukchi Sea in August or September, with open water
conditions persisting over much of the continental shelf through late
October. In contrast, during the preceding 20 years (1979-1998), broken
sea-ice habitat persisted over continental shelf areas of the Chukchi
Sea through the entire summer (Jay and Fischbach 2008, p. 1).
From 1979 to 2007, there was a general trend toward earlier onset
of ice melt and later onset of freeze-up in 9 of 10 Arctic regions
analyzed by Markus et al. (2009, pp. 1-14), the exception being the Sea
of Okhotsk. For the entire Arctic, the melt season length has increased
by about 20 days over the last 30 years, due to the combined earlier
melt and later freeze-up. The largest increases, of over 10 days per
decade, have been seen for Hudson Bay, the East Greenland Sea, and the
Laptev/East Siberian Seas. From 1979 to 2007, there was a general trend
toward earlier onset of ice melt and later onset of freeze-up in both
the Bering and Chukchi Seas: For the Bering Sea, the onset of ice melt
occurred 1.0 day earlier per decade, while in the Chukchi/Beaufort Seas
ice melt occurred 3.5 days earlier per decade. The onset of freeze-up
in the Bering Sea occurred 1.0 day later per decade, while freeze-up in
the Chukchi/Beaufort Seas occurred 6.9 days later per decade (Markus et
al. 2009, p. 11).
Later freeze-up in the Arctic does not necessarily mean that less
seasonal sea ice forms by winter's end in the peripheral seas, such as
the Bering and Chukchi Seas (Boveng et al. 2008, p. 35). For example,
in 2007 (the year when the record minimal Arctic summer sea-ice extent
was recorded), the Chukchi Sea did not freeze until early December and
the Bering Sea remained largely ice-free until the middle of December
(Boveng et al. 2008, p. 35). However, rapid cooling and advancing of
sea ice in late December and early January resulted in most of the
eastern Bering Sea shelf being ice-covered by mid-January, an advance
of 900 km (559 mi), or 30 km per day (19 mi per day). Maximum ice
extent occurred in late March, with ice covering much of the shelf,
resulting in a near record maximum ice extent. Ice then slowly
retreated, and the Bering Sea was not ice-free until almost July.
Therefore, winter ice conditions are not necessarily related to the
summer-fall ice conditions of the previous year.
Model Projections of Future Sea Ice
The analysis and synthesis of information presented by the
Intergovernmental Panel on Climate Change (IPCC) in its Fourth
Assessment Report (AR4) in 2007 represents the scientific consensus
view on the causes and future of climate change. The IPCC AR4 used
state-of-the-art Atmosphere-Ocean General Circulation Models (GCMs) and
a range of possible future greenhouse gas (GHG) emission scenarios to
project plausible outcomes globally and regionally, including
projections of temperature and Arctic sea-ice conditions through the
The GCMs use the laws of physics to simulate the main components of
the climate system (the atmosphere, ocean, land surface, and sea ice)
and to make projections as to the response of these components to
future emissions of GHGs. The IPCC used simulations from about 2 dozen
GCMs developed by 17 international modeling centers as the basis for
the AR4 (Randall et al. 2007, pp. 596-599). The GCM results are
archived as part of the Coupled Model Intercomparison Project-Phase 3
(CMIP3) at the Program for Climate Model Diagnosis and Intercomparison
(PCMDI). The CMIP3 GCMs provide projections of future effects that
could result from climate change, because they are built on well-known
dynamical and physical principles, and they plausibly simulate many
large-scale aspects of present-day conditions. However, the coarse
resolution of most current climate models dictates careful application
on smaller spatial scales in heterogeneous regions.
The IPCC AR4 used six ``marker'' scenarios from the Special Report
on Emissions Scenarios (SRES) (Carter et al. 2007, p. 160) to develop
climate projections spanning a broad range of GHG emissions through the
end of the 21st century under clearly stated assumptions about
socioeconomic factors that could influence the emissions. The six
``marker'' scenarios are classified according to their emissions as
``high'' (A1F1, A2),
``medium'' (A1B and B2) and ``low'' (A1T, B1). The SRES made no
judgment as to which of the scenarios were more likely to occur, and
the scenarios were not assigned probabilities of occurrence (Carter et
al. 2007, p. 160). The IPCC focused on three of the marker scenarios--
B1, A1B, and A2--for its synthesis of the climate modeling efforts,
because they represented ``low,'' ``medium,'' and ``high,'' scenarios;
this choice stemmed from the constraints of available computer
resources that precluded realizations of all six scenarios by all
modeling centers (Meehl et al. 2007, p. 753). With regard to these
three emissions scenarios, the IPCC Working Group I report noted:
``Qualitative conclusions derived from these three scenarios are in
most cases also valid for other SRES scenarios'' (Meehl et al. 2007, p.
761). It is important to note that the SRES scenarios do not contain
additional climate initiatives (e.g., implementation of the United
Nations Framework Convention on Climate Change or the emissions targets
of the Kyoto Protocol) beyond current mitigation policies (IPCC 2007,
p. 22). The SRES scenarios do, however, have built-in emissions
reductions that are substantial, based on assumptions that a certain
amount of technological change and reduction of emissions would occur
in the absence of climate policies; recent analysis shows that two-
thirds or more of all the energy efficiency improvements and
decarbonization of energy supply needed to stabilize GHGs is built into
the IPCC reference scenarios (Pielke et al. 2008, p. 531).
There are three main contributors to divergence in GCM climate
projections: Large natural variations, across-model differences, and
the range-in-emissions scenarios (Hawkins and Sutton 2009, p. 1096).
The first of these, variability from natural variation, can be
incorporated by averaging the projections over decades, or, preferably,
by forming ensemble averages from several runs of the same model.
The second source of variation is model to model differences in the
way that physical processes are incorporated into the various GCMs.
Because of these differences, projections of future climate conditions
depend, to a certain extent, on the choice of GCMs used. Uncertainty in
the amount of warming out to mid-century is primarily a function of
these model-to-model differences. The most common approach to address
the uncertainty and biases inherent in individual models is to use the
median or mean outcome of several predictive models (a multi-model
ensemble) for inference. Excluding models that poorly simulate
observational data is also a common approach to reducing the spread of
uncertainty among projections from multi-model ensembles.
The third source of variation arises from the range in plausible
GHG emissions scenarios. Conditions such as surface air temperature and
sea-ice area are linked in the IPCC climate models to GHG emissions by
the physics of radiation processes. When CO2 is added to the
atmosphere, it has a long residence time and is only slowly removed by
ocean absorption and other processes. Based on IPCC AR4 climate models,
expected global warming--defined as the change in global mean surface
air temperature (SAT)--by the year 2100 depends strongly on the assumed
emissions of CO2 and other GHGs. By contrast, warming out to
about 2040-2050 will be largely due to emissions that have already
occurred and those that will occur over the next decade (Meehl 2007, p.
749). Thus, conditions projected to mid-century are less sensitive to
assumed future emission scenarios. For the second half of the 21st
century, however, and especially by 2100, the choice of the emission
scenario becomes the major source of variation among climate
projections and dominates over natural variability and model-to-model
differences (IPCC 2007, pp. 44-46).
Because the SRES group and the IPCC made no judgment on the
likelihood of any of the scenarios, and the scenarios were not assigned
probabilities of occurrence, one option for representing the full range
of variability in potential outcomes, would be to evaluate projections
from all models under all marker scenarios for which sea-ice
projections are available to the scientific community--A2, A1B, and B1.
Another typical procedure for projecting future outcomes is to use an
intermediate scenario, such as A1B, to predict changes, or one
intermediate and one high scenario (e.g., A1B and A2) to capture a
range of variability.
Several factors suggest that the A1B scenario may be a particularly
appropriate choice of scenario to use for projections of sea-ice
declines in the Arctic and its marginal seas. First, the A1B scenario
is widely used in modeling because it is a ``medium'' emissions
scenario characterized by a future world of very rapid economic growth,
global population that peaks in mid-century and declines thereafter,
rapid introduction of new and more efficient technologies, and
development of energy technologies that are balanced across energy
sources, and it contains no assumption of mitigation policies that may
or not be realized. Thus, there are a number of studies in the
published sea-ice literature that use the A1B scenario and can,
therefore, be used for comparative purposes (e.g., Overland and Wang
2007; Holland et al. 2010; Wang et al. 2010). Second, both the A1B and
A2 scenarios project similar declines in hemispheric sea-ice extent out
to 2100 (Meehl et al. 2007, Figure 10.13, p. 771); thus, little new
understanding is gained by using projections from both scenarios (see
discussion of Douglas 2010 in subsequent paragraphs). Third, model
projections based on the B1 scenario appear to be overly conservative
(Meehl et al. 2007, Figure 10.13, p. 771), in that sea ice is declining
even faster than the decline forecasted by the A1B scenario (see
discussion at end of this section). Fourth, current global carbon
emissions appear to be tracking slightly above (Raupach et al. 2007,
Figure 1, p. 10289; LeQuere et al. 2009, Figure 1a, p. 2; Global Carbon
Project 2010 at http://www.globalcarbonproject.org/carbonbudget/09/files/GCP2010_CarbonBudget2009_29November2010.pdf) or slightly below
(Manning et al. 2010, Figure 1, p. 377) the A1B trajectory at this
point in time. It may be reasonable to project this or a higher trend
in global carbon emissions into the near future (Garnaut et al. 2008,
Figure 5, p. 392; Sheehan 2008, Figure 2, p. 220; but see caveat by van
Vuuren et al. 2010). Fifth, there is a growing body of opinion that
stabilizing GHG emissions at levels well below the A1B scenario (e.g.,
at 450 parts per million (ppm), equivalent to a 2 degree Celsius
increase in temperature) will be difficult in the absence of
substantial policy-mandated mitigation (e.g., Garnaut et al. 2007, p.
398; den Elzen and H[ouml]hne 2008, p. 250; Pielke et al. 2008, pp.
531-532; Macintosh 2009, p. 3; den Elzen et al. 2010, p. 314; Tomassini
et al. 2010, p. 418; Anderson and Bows 2011, p. 20), largely as a
result of continuing high emissions in certain developed countries, and
recent and projected growth in the economies and energy demands of
rapidly developing countries (e.g., Garnaut et al. 2008, p. 392;
Auffhammer and Carson 2008, p. 1; Pielke et al. 2008, p. 532; U.S.
Energy Information Administration 2010, pp. 123-124, 128). Because of
these factors, we conclude that sea-ice projections developed by using
the A1B forcing scenario provide an appropriate basis for evaluating
potential impacts to habitat and related impacts to the Pacific walrus
population in the future.
Our analysis of sea-ice response to global warming within the range
Pacific walrus (Bering and Chukchi Seas) carefully considered the
synthesis of GCM projections presented by Douglas (2010). We provide a
broad overview of the methods and findings of the report by Douglas
(2010), details of which are available in the full report.
Douglas (2010, pp. 4-5) quantified sea-ice projections (from the A2
and A1B scenarios) by 18 CMIP3 GCM models prepared for the IPCC fourth
reporting period, as well as 2 GCM subsets which excluded models that
poorly simulated the 1979-2008 satellite record of Bering and Chukchi
sea-ice conditions. Analyses focused on the annual cycle of sea-ice
extent within the range of the Pacific walrus population, specifically
the continental shelf waters of the Bering and Chukchi Seas. Models
were selected for the two subsets, respectively, when their simulated
mean ice extent and seasonality during 1979-2008 were within two
standard deviations (SD2) and one standard deviation (SD1) of the
observed means. In consideration of observations of ice-free conditions
across the Chukchi Sea in recent years in late summer, any models that
failed to simulate at least 1 ice-free month in the Chukchi Sea were
also excluded from the Chukchi Sea subset ensembles. Ice observations
and the projections of individual GCMs were pooled over 10-year periods
to integrate natural variability (Douglas 2010, p. 5).
To quantify projected changes in monthly sea-ice extent, Douglas
(2010, p. 31) compared future monthly sea-ice projections for the
Bering and Chukchi Seas at mid-century (2045-2054) and late-century
(2090-2099) with two decades from the observational record (1979-1988
and 1999-2008). The earliest observational period (1979-1988), which
coincides with a timeframe during which the Pacific walrus population
was considered to be occupying most of its historical range (Fay 1982,
pp. 7-21), provides a useful baseline for examining projected changes
in sea-ice habitats.
Douglas (2010, p. 7) found that projected median sea-ice extents
under both the A1B and A2 forcing scenarios are qualitatively similar
in the Bering and Chukchi Seas in all seasons throughout the 21st
century. This finding is consistent with the generally similar declines
in hemispheric sea-ice extent between the A1B and A2 scenarios out to
2100 (Meehl et al. 2007, Figure 10.13, p. 771). Thus, our decision to
focus on ice projections by the A1B forcing scenario (as described
above) is further substantiated, as there would be little insight
gained by considering the A2 scenario.
The analysis of Douglas (2010, pp. 24, 31) yields mid-century
projections that indicate sea-ice extent in the Bering Sea will decline
for all months when sea ice has historically been present, i.e., for
October through June. The most pronounced reductions in Bering Sea ice
extent at mid-century in terms of the percent change from baseline
conditions are expected in the months of June and November, which
reflects an increasingly early onset of ice-free or nearly ice-free
conditions in the early summer and later onset of sea-ice development
in the fall. In June, the projected extent of sea ice is -63 percent of
the 1979-1988 baseline level, while the projected extent for November
is approximately is -88 percent of the baseline level. By late century,
substantial declines in Bering Sea ice extent are projected for all
months, with losses ranging from 57 percent in April, to 100 percent
loss of sea ice in November (Douglas 2010, p. 31). The onset of
substantial freezing in the Bering Sea is projected to be delayed until
January by late century, with little or no ice projected to remain in
May by the end of the century (Douglas 2010, pp. 8, 24, 31).
Historically, sea-ice cover has persisted, to at least some extent,
over continental shelf waters of the Chukchi Sea all 12 months of the
year, although the extent of sea ice has varied by month. For example,
for the 1979-1988 period, the median extent of sea ice varied from
about 50 percent in September to essentially 100 percent from late
November through early May (Douglas 2010, p. 19). A pattern of
extensive sea-ice cover (approaching 100 percent) in late winter and
early spring (February-April) is expected to persist through the end of
Projections of sea-ice loss during June in the Chukchi Sea are
relatively modest; however, the sea ice is projected to retreat rapidly
during the month of July (Douglas 2010, p. 12). Model subset medians
project a 2-month ice-free season at mid-century and a 4-month ice-free
season at the end of the century, centered around the month of
September (Douglas 2010, pp. 8, 22, 24), with some models showing up to
5 months ice-free by end of the century (Douglas 2010, pp. 12, 22, 24).
In the most recent observational decade (1999-2008), the southern
extent of the Arctic ice pack has retreated and advanced through the
Bering Strait in the months of June and November, respectively. By the
end of the century, these transition months may shift to May (1 month
earlier) and January (2 months later), respectively (Douglas 2010, pp.
The projected loss of sea ice involves uncertainty. In discussing
this, Douglas 2010 (p. 11) states, in part: ``Ice-free conditions in
the Chukchi Sea are attained for a 3-month period (August-October) at
the end of the century (fig 7) with almost complete agreement among
models of the SD2 subset (fig 12). Consequently, a higher degree of
confidence can accompany hypotheses or decisions premised on this
outcome and timeframe.'' Douglas also notes there is greater confidence
in projections that the Chukchi Sea will continue to be completely ice
covered during February-April at the end of century, and that large
uncertainties are prevalent during the melt and freeze seasons,
particularly June, November, and December (Douglas 2010, p. 11).
Several other investigations have analyzed model projections of
sea-ice change in the Bering and Chukchi Seas and reported results that
are consistent with those of Douglas (2010). Wang et al. (2010, p. 258)
investigated sea-ice projections to mid-century for the Bering Sea
using a subset of models selected on the basis of their ability to
simulate sea-ice area in the late 20th century. Their projections show
an average decrease in March-April sea-ice coverage of 43 percent by
the decade centered on 2050, with a reasonable degree of consistency
among models. Boveng et al. (2008, pp. 39-40) analyzed a subset of IPCC
AR4 GCM models (selected for accuracy in simulating observed ice
conditions) to evaluate spring (April-June) conditions in the Bering
Sea out to 2050. Their analysis suggested that by mid-century, a modest
decrease in the extent of sea ice in the Bering Sea is expected during
the month of April, and that ice cover in May will remain variable,
with some years having considerably reduced ice cover. June sea-ice
cover in the Bering Sea since the 1970s has been consistently low or
absent. Their models project that by 2050, ice cover in the Bering Sea
will essentially disappear in June, with only a rare year when the ice
cover exceeds 0.05 million sq km (0.03 million sq mi) (Boveng et al.
2008, pp. 39-40), a projection similar to that reported by Douglas
(2010, p. 24).
Boveng et al. (2009, pp. 44-54) used a subset of IPCC AR4 models to
further investigate sea-ice coverage in the eastern Bering Sea (the
area of greatest walrus distribution in the Bering Sea), Bering Strait,
and the Chukchi Sea out to 2070. For the eastern Bering Sea, they
projected that sea-ice coverage will decline in the spring and fall,
with fall declines exceeding those of spring. By 2050, average sea-ice
extent in November and December would be
approximately 14 percent of the 1980-1999 mean, while sea-ice extent
from March to May would be about 70 percent of the 1980-1999 mean. For
the Bering Strait region, the model projections indicated a longer ice-
free period by 2050, largely as a result of decreasing ice coverage in
November and December. By 2050, they project that the March-May sea-ice
extent in the Bering Strait region would be 80 percent of the 1980-1999
mean, while November ice extent would be 20 percent of the mean for
that reference period. For the Chukchi Sea, Boveng et al. (2009, pp.
49-50) reported a projected reduction in sea-ice extent for November by
2050, a slight decline for June by 2070, and a clear reduction for
November and December by 2070.
Several authors note that sea-ice extent in the Arctic is
decreasing at a rate faster than projected by most IPCC-recognized GCMs
(Stroeve et al. 2007, p. 1; Overland and Wang 2007, p. 1; Wang and
Overland 2009, p. 1; Wang et al. 2010, p. 258), suggesting that GCM
projections of 21st century sea-ice losses may be conservative (Douglas
2010, p. 11, and citations therein) and that ice-free conditions in
September in the Arctic may likely be achieved sooner than projected by
most models using the A1B forcing scenario. In describing the ``faster
than forecast'' situation, Douglas notes that the minimum ice extents
in the Arctic for the summers of 2007-2009 were well below the previous
record set in 2005, and concurs that serious consideration must be
given to the possibility that the CMIP3 GCM projections collectively
yield conservative time frames for sea-ice losses in this century
(Douglas 2010, p. 11); i.e., the projected changes he reports for the
range of the Pacific walrus may occur sooner than the model projections
In conclusion, the actual loss of sea ice in recent years in the
Arctic has been faster than previously forecast, current GHG emissions
are at or above those expected under the A1B scenario that we (and most
scientists studying Arctic sea ice) relied on, models converge in
predicting the extended absence of sea ice in the Chukchi Sea at the
end of the century (Douglas 2010, pp. 12, 29), and there has been a
marked loss of sea ice over the Chukchi Sea in the past decade. The
best scientific information available gives us a high level of
confidence that despite some uncertainty among the models, the
projections are generally consistent and provide a reliable basis for
us to conclude that sea-ice loss in the range of the Pacific walrus has
a high likelihood of continuing.
Effects of Changing Sea-Ice Conditions on Pacific Walruses
The Pacific walrus is an ice-dependent species. Walruses are poorly
adapted to life in the open ocean and must periodically haul out to
rest. Floating pack ice creates habitat from which breeding behavior is
staged (Fay et al. 1984, p. 81), and it provides a platform for calving
(Fay 1982, p. 199), access to offshore feeding areas over the
continental shelf of the Bering and Chukchi Seas, passive
transportation among feeding areas (Ray et al. 2006, pp. 404-407), and
isolation from terrestrial predators and hunters. In this section, we
first analyze the effects of sea-ice loss on breeding and calving,
because these are essential life-history events that depend on ice in
specific seasons. In the second part of this section, we analyze how
the anticipated increasing use of coastal haulouts due to the loss of
sea-ice habitat may cause localized prey depletion and affect walrus
foraging, as well as increase their susceptibility to trampling,
predation, and hunting.
Effects of Sea-Ice Loss on Breeding and Calving
During the January-to-March breeding season, walruses congregate in
the Bering Sea pack ice (Fay 1982, pp. 8-11, 193; Fay et al. 1984, pp.
89-99), where the ice creates the stage for breeding. Females
congregate in herds on the ice and the bulls station themselves in the
water alongside the herd and perform visual and acoustical displays
(Fay 1982, p. 193). Breeding aggregations have been reported southwest
of St. Lawrence Island, Alaska, south of Nunivak Island, Alaska, and
south of the Chukotka Peninsula in the Gulf of Anadyr, Russia (Fay
1982, p. 21; Mymrin et al. 1990, pp. 105-113). It is unlikely that
breeding is tied to a specific geographic location, because of the
large seasonal and inter-annual variability in sea-ice cover in the
Bering Sea at this time of year. Fay et al. (1984, p. 80) indicate
probable changes in the locations of breeding aggregations based on
differing amounts of sea ice. We anticipate that seasonal pack ice will
continue to form across large areas of the northern Bering Sea,
primarily in January-March, and will persist in most years through
April (Douglas 2010, p. 25).
The distribution of walruses during the winter breeding season will
likely shift in the future in response to changing patterns of sea-ice
development. Core areas of winter abundance south of Saint Lawrence
Island and the Gulf of Anadyr will likely continue to have adequate ice
cover to support breeding aggregations through mid-century, as the
extent of sea ice will still be relatively substantial, although
slightly diminished from the current extent (Douglas 2010, p. 25).
Walruses currently wintering in Northern Bristol Bay will likely shift
their distribution northward in response to the projected loss of
seasonal pack ice in this region (Douglas 2010, p. 25). By the end of
the century, winter sea-ice extent across the Bering Sea is expected to
be greatly reduced, and the median sea-ice edge is projected to be
farther to the north (Douglas 2010, p. 25). Based on these projections,
core areas of winter abundance and breeding aggregations will likely
shift farther north. Potentially, the breeding aggregations may shift
into areas north of the Bering Strait in the southern Chukchi Sea in
some years by the end of the century (Douglas 2010, pp. 24, 28).
Although the location of winter breeding aggregations will likely
shift in response to projected reductions in sea-ice extent, sea-ice
platforms for herds of females will persist during the breeding season;
therefore, we conclude that suitable conditions for breeding will
likely persist into the foreseeable future. We have no information that
indicates that the specific location of the ice is important, and sea
ice is expected to remain over shallow, food-rich areas. Therefore, we
do not consider changes in sea-ice extent during the winter breeding
season to be a threat now or in the foreseeable future.
Female walruses typically give birth to a single calf in May on sea
ice, shortly before or during the northward spring migration through
the Bering Strait. By mid-century, ice extent in the Bering Strait
Region is projected to be reduced during the May calving season, and by
end of century, the Bering Sea is projected to be largely sea-ice-free
during the month of May (Douglas 2010, p. 25). As is the case with
breeding, the birth of a calf and the natal period in the weeks that
follow are probably not tied to specific geographic locations. It is
reasonable to assume that suitable ice conditions for calving and post-
calving activity on sea ice will persist into the foreseeable future,
even though the location of favorable ice conditions is likely to shift
further to the north over time.
We conclude that changes in sea ice during the spring calving
season (April-May) are not a threat now or in the foreseeable future.
We have no
information that indicates the specific location of the ice is
important, and sea ice would remain over shallow, food-rich areas.
Summary of Effects of Sea-Ice Loss on Breeding and Calving
Breeding and calving activities utilize ice as a platform in the
months of January through May. Based on our current understanding of
these activities, the specific location of the ice is not important.
Although sea-ice extent is projected to move northward over time, sea
ice is expected to persist in these months and be available for these
life history functions. Therefore, we do not consider changes in sea-
ice extent to be a threat to breeding or calving activities now or in
the foreseeable future.
Effects of Increasing Dependence on Coastal Haulouts Due to Sea-Ice
We begin this discussion with a summary of sea-ice loss projections
and recent observations. We follow with an analysis of the potential
effects to Pacific walrus from an increasing dependence on coastal
haulouts, particularly in the Chukchi Sea, and examine the use of
coastal haulouts by Atlantic walrus as a potential analog for Pacific
walrus coastal haulout use. We analyze potential effects of increased
dependency on coastal haulouts resulting from the loss of sea-ice
habitats. Some of the effects to Pacific walrus that we have identified
as a result of increasing dependence on coastal haulouts (i.e.,
trampling, predation, and hunting) would typically be discussed under
other Factors. These effects are discussed in this section in the
context of responses to declining sea ice; however, it should be noted
that we also discuss predation under Factor C (Disease or Predation),
and hunting under Factor B (Overutilization for Commercial,
Recreational, Scientific, or Educational Purposes) and Factor D (The
Inadequacy of Existing Regulatory Mechanisms).
Summary of Sea-Ice Loss Projections
Sea ice has historically persisted over continental shelf regions
of the Chukchi Sea through the entire melt season. Over the past
decade, sea ice has begun to retreat beyond shallow continental shelf
waters in late summer. The recent trend of rapid ice loss from
continental shelf regions of the Chukchi Sea in July and August is
projected to persist, and will likely accelerate in the future (Douglas
2010, p. 12). The onset of ice formation in the fall over continental
shelf regions in the Chukchi and Bering Seas is expected to be delayed,
and by mid-century (2045-2054), ice-free conditions over most
continental shelf regions of the Chukchi Sea are projected to persist
for 2 months (August-September). By late century, ice-free (or nearly
sea-ice-free) conditions may persist for 3 months, and extend to 4 to 5
months in some years (Douglas 2010, pp. 8, 12, 22, 27). The average
number of ice-free months in the Bering Sea is projected to increase
from the approximately 5.5 months currently, to approximately 6.5 and
8.5 months at mid- and end of century, respectively (Douglas 2010, pp.
Observed and Expected Responses of Pacific Walruses to Declining Sea-
Adult male walruses make greater use of coastal haulouts during
ice-free seasons than do females and dependent young, and consequently,
have a broader distribution during ice-free seasons. Several thousand
bulls remain in the Bering Sea through the ice-free summer months,
where they make foraging excursions from coastal haulouts in Bristol
Bay, Alaska and the Gulf of Anadyr, Russia. The size of these haulouts
has changed over time; for example, at Round Island, the number of
hauled out walruses grew from about 3,000 animals in the late 1950s to
about 12,000 in the early 1980s (Jay and Hills 2005, p. 193), and has
subsequently declined to 2,000-5,000 animals in the past decade (Sell
and Weiss 2010, p. 12). The reasons for changes in walrus haulout use
in the Bering Sea are poorly understood. Factors that could affect use
of haulouts include; prey abundance and distribution, walrus density,
and physical alteration or chronic disturbance at the haulouts (Jay and
Hills 2005, p. 198). Tagged males traveled up to 130 km (81 mi) to feed
from haulout sites in Bristol Bay (Jay and Hills 2005, p. 198). Because
the benthic densities are poorly documented, it is not possible to link
the changes in haulout use by males to prey depletion. However, non-use
of areas with shallow depths closer to the haulouts suggests prey was
not adequate for effective foraging (Jay and Hills 2005, p. 198). Males
have an advantage over females in that they are bigger and stronger and
have no responsibilities related to the care of calves, and thus, can
travel as far as necessary to locate food. Currently, males utilize
terrestrial haulouts for 5 months or more (Jay and Hills 2005, p. 198).
It is unlikely that the projected increase in ice-free months in the
Bering Sea will alter male behavior or survival rates at terrestrial
haulouts because the adult males that utilize Bering Sea haulouts do
not rely on sea ice as a foraging platform. Indirect effects of global
climate change on walrus prey species in this region are considered
separately below in the section: Effects of Global Climate Change on
Pacific Walrus Prey Species.
Most of the Pacific walrus population (adult females, calves,
juveniles, and males that have not remained at coastal haulouts in the
Bering Sea) migrate northward in spring following the retreating pack
ice through the Bering Strait to summer feeding areas over the
continental shelf in the Chukchi Sea. Historically, sufficient pack-ice
habitat has persisted over continental shelf regions of the Chukchi Sea
through the summer months such that walruses in the Chukchi Sea did not
rely on coastal haulouts with great frequency or in large numbers. Over
the past decade, however, sea ice has begun to retreat north beyond
shallow continental shelf waters of the Chukchi Sea in late summer.
This has caused walruses to relocate to coastal haulouts, which they
use as sites for resting between foraging excursions. The number of
walruses using land-based haulouts along the Chukchi Sea coast during
the summer months, and the duration of haulout use, has increased
substantially over the past decade, with up to several tens of
thousands of animals hauling out at some locations along the coast of
Russia during ice-free periods (Ovsyanikov et al. 2007, pp. 1-2;
Kochnev 2008, p. 17-20, Kavry et al. 2008, p. 248-251). Coastal
haulouts have also begun to form along the Arctic coast of Alaska in
recent years (2007, 2009, and 2010) when sea ice retreated north of the
continental shelf in late summer (Service 2010, unpublished data). The
occupation of terrestrial haulouts along the Chukchi Sea coast for
extended periods of time in late summer and fall represents a
relatively new and significant change from traditional habitat use
patterns. The consequences of this observed and projected shift in
habitat use patterns is the primary focus of our analysis.
As sea ice withdraws from offshore feeding areas over the
continental shelf of the Chukchi Sea, walruses are expected to become
increasingly dependent on coastal haulouts as a foraging base during
the summer months. With a delay the onset of ice formation in the fall,
and in the absence of sea-ice cover in the southern Chukchi Sea and
northern Bering Sea in the summer, walruses will likely remain at
coastal haulouts for longer periods of time until sea ice reforms in
the fall or early winter. By the end of the century, dependence on
Chukchi Sea coastal haulouts by mixed groups of walruses
for resting and as a foraging base may extend from July into early
winter (December-January), when there may be up to a 2-month delay in
freeze-up (Douglas 2010, pp. 12, 22). This expectation is consistent
with observations made by Russian scientists that some of the coastal
haulouts along the southern Chukchi Sea coast of Russia have persisted
in recent years into December (Kochnev 2010, pers. comm.).
Increased dependence on coastal haulouts creates the following
potential impacts for walruses: Changes in foraging patterns and prey
depletion; increased vulnerability to mortality or injury due to
trampling, especially for calves, juveniles, and females; greater
vulnerability to mortality or injury from predation; and greater
vulnerability to mortality due to hunting. Each is discussed in detail
Changes in Foraging Patterns and Prey Depletion
The loss of seasonal pack ice from continental shelf areas of the
Chukchi Sea is expected to reduce access to traditional foraging areas
across the continental shelf and increase competition among individuals
for food resources in areas close to haulouts. Information regarding
the density of walrus prey items accessible from coastal haulouts is
limited; however, some haulouts have supported sizable concentrations
of animals (up to several tens of thousands of animals) for periods of
up to 4 months in recent years (Kochnev 2010, pers. comm.). Many walrus
prey species are slow growing and potentially vulnerable to
overexploitation, and intensive foraging from coastal haulouts by large
numbers of walruses may eventually result in localized prey depletion
(Ray et al. 2006, p. 412). A walrus requires approximately 29 to 74 kg
(64 to 174 lbs) of food per day (Fay 1982, p. 160), and may consume
4,000 to 6,000 clams in one feeding bout (Ray et al. 2006, pp. 408,
412); therefore, when large numbers of walruses are concentrated on
coastal haulouts, a large amount of prey (whether clams or other types
of prey) must be available to support them.
The presence of large numbers of walruses at a coastal haulout over
an extended time period could eventually lead to localized prey
depletion. The most likely response to localized prey depletion will be
for walruses to seek out and colonize other terrestrial haulouts that
have suitable foraging areas (Jay and Hills 2005, p. 198). However,
prey densities along the Arctic coast are not uniform (Grebmeier et al.
1989, p. 257; Feder et al. 1994, pp. 176-177; Grebmeier et al. 2006b,
p. 346), and many coastal areas which provide the physical features of
a suitable haulout, may not have sufficient food sources. A visual
comparison of areas of high benthic production (e.g., Springer et al.
1996, p. 209; Dunton et al. 2005, p. 3468; Grebmeier et al. 2006b, p.
346) and areas that have supported large terrestrial haulouts of
walruses (e.g., Cape Inkigur, Cape Serdtse-Kamen) indicates that
walruses have historically selected sites near areas of very high
benthic productivity. Benthic productivity along part of the western
shore of Alaska (i.e., along the eastern edge of the Chukchi Sea) is
low because of the nutrient-poor waters of the Alaska Coastal Current,
especially for instance, in the Kotzebue Sound (Dunton et al. 2005, p.
3468; Dunton et al. 2006, p. 369; Grebmeier et al. 2006b, p. 346).
Consequently, the number of sites with adequate food resources to
support large aggregations of walruses is likely limited.
A consequence of prey depletion could be an increased energetic
cost to locate sufficient food resources (Sheffield and Grebmeier 2009,
p. 770; Jay et al. 2010b, pp. 9-10). Energetic costs to walruses will
increase if they have to travel greater distances to locate prey, or
foraging efficiency is reduced as a consequence of lower prey densities
(Sheffield and Grebmeier 2009, p. 770; Jay et al. 2010b, pp. 9-10).
Observations by Russian scientists at haulouts along the coast of
Chukotka (along the western side of the Chukchi Sea) in recent years
suggest that rates of calf mortality and poor body condition of adult
females are inversely related to the persistence of sea ice over
offshore feeding areas and the length of time that animals occupy
coastal haulouts (Nikiforov et al. 2007, pp. 1-2; Ovsyanikov et al.
2007, pp. 1-3; Kochnev 2008, pp. 17-20; Kochnev et al. 2008, p. 265).
Over time, poor body condition could lead to lower reproductive rates,
greater susceptibility to disease or predation, and ultimately higher
mortality rates (Kochnev 2004, pp. 285-286; Kochnev et al. 2008, p.
265; Sheffield and Grebmeier 2009, p. 770).
The energetic cost of swimming a long distance is demonstrated by
the observations made in the summer of 2007, when the melt season in
the Chukchi Sea began slowly, and then sea-ice retreat accelerated
rapidly in July and August. The continental shelf of the Chukchi Sea
was sea-ice-free by mid-August; the ice edge eventually retreated
hundreds of miles north of the shelf, and ice did not re-form over the
continental shelf until late October (National Snow and Ice Data
Center, 2007). Ovsyanikov et al. (2007, pp. 2-3) reported that many of
the walruses arriving at Wrangel Island, Russia, in August 2007 were
emaciated and weak, some too exhausted to flee or defend themselves
from polar bears patrolling the coast. The authors attributed the poor
condition of these animals to the rapid retreat of sea ice off of the
shelf in July to waters too deep for walrus to feed. They also noted
that the exhausted walruses could not find enough food near the island
for recovery (Ovsyanikov et al. 2007, p. 3).
Females with dependent young are likely to be disproportionally
affected by prey depletion and increased reliance on coastal haulouts
as a foraging base. Females with dependent young require two to three
times the amount of food needed by nonlactating females (Fay 1982, p.
159). Over the past decade, females and dependent calves have responded
to the loss of sea ice in late summer by occupying coastal haulouts
along the coast of Chukotka, Russia, and more recently (2007-2010)
haulouts along the coast of Alaska. Females typically nurse their
calves between short foraging forays from sea-ice platforms situated
over productive forage areas (Ray et al. 2006, pp. 404-407). Drifting
ice provides walrus passive transport and access to new foraging areas
with minimal effort. In 2007, radio-tagged females traveled on average,
30.7 km (19 mi) on foraging trips from several haulouts located along
the Chukotka coastline (Kochnev et al. 2008, p. 265). Although we do
not know the average distance of foraging trips taken from an ice
platform, in general, we would expect them to be relatively short,
because when the ice is over productive prey areas, the female only has
to dive to the bottom and back up to the ice (Ray et al. 2006, pp. 406-
407). Because calves do not have the swimming endurance of adults, if
sufficient prey is not located within the swimming distance of the
calf, the female either may not be able to obtain adequate nutrition or
the calf may be abandoned when the female travels to locations beyond
the swimming capability of the calf (Cooper et al. 2006, pp. 98-102).
Lack of adequate prey for females could eventually lead to reduced body
condition, lower reproductive success, and potentially death. Abandoned
calves could face increased mortality from drowning, starvation, or
In summary, by the end of the 21st century, ice-free conditions are
expected to persist across the continental shelf of the Chukchi Sea for
a period of up to several months (Douglas 2010). Based
on the observed responses of walruses to periods of low ice cover in
the Chukchi Sea in recent years, we expect walruses to become
increasingly dependent on coastal haulouts as a foraging base, with
animals restricted to coastal haulouts for most of the summer and into
the fall and early winter. Walruses have the ability to use land in
addition to ice as a resting site and foraging base, which will provide
them alternate, if not optimal (as explained above), resting habitat.
However, given the concentration of large numbers of animals in
relatively small areas, the large amount of prey needed to sustain each
walrus, and the increasing length of time coastal haulouts will have to
be used due to sea-ice loss, the increased dependence on coastal
haulouts is expected to result in increased competition for food
resources in areas accessible from the coastal haulouts. Because of the
energetic demands of lactation and limited mobility of calves, female
walruses with dependent young are likely to be disproportionally
affected by changes in habitat use patterns. Because near-shore food
resources are unlikely to be able to support the current population,
walruses will be required to swim farther to obtain prey, which will
increase energetic costs. Accordingly, near-shore prey depletion will
likely result in a population decline over time. It is unlikely that
the projected increase in ice-free months in the Bering Sea will alter
the behavior or survival rates of males at terrestrial haulouts because
these males do not rely on sea ice as a foraging platform. In addition,
males have an advantage over females in that they are bigger and
stronger and have no responsibilities related to the care of calves,
and thus, can travel as far as necessary to forage.
The degree to which depletion of food resources near coastal
haulouts will limit population size will depend on a variety of
factors, including: The location of coastal walrus haulouts, the number
of animals utilizing the haulouts, the duration of time walruses occupy
the haulouts, and the robustness of the prey base within range of those
haulouts. However, it is highly unlikely that the current population
can be sustained from coastal haulouts alone. In particular, females
and their calves will be susceptible to the increased energetic demands
of foraging from coastal haulouts. We do not anticipate effects to
males using coastal haulouts in the Bering Sea, because their current
behavior can continue unaltered into the future. We do not have
evidence that prey depletion is currently having a population-level
effect on the Pacific walrus. Our concern is based on projections of
continued and more extensive sea-ice loss that will force the animals
onto land. Therefore, we conclude that loss of sea-ice habitat, leading
to dependence on coastal haulouts and localized prey depletion, will
contribute to other negative impacts associated with sea-ice loss, and
is a threat to the Pacific walrus in the foreseeable future.
Increased Vulnerability to Disturbances and Trampling
Another consequence of greater reliance on coastal haulouts is
increased levels of disturbances and increased rates of mortalities and
injuries associated with trampling. Walruses often flee land or ice
haulouts in response to disturbances. Disturbance can come from a
variety of sources, either anthropogenic (e.g., hunters, airplanes,
ships) or natural (e.g., predators) (Fay et al. 1984, pp. 114-118,
Kochnev 2004, p. 286). Haulout abandonment represents an increase in
energy expenditure and stress, and disturbance events at densely packed
coastal haulouts can result in intra-specific trauma and mortalities
(COSEWIC 2006, pp. 25-26). Although disturbance-related mortalities at
all-male haulouts in the Bering Sea are relatively uncommon (Fay and
Kelly 1980, p. 244; Kochnev 2004, p. 285), the situation at mixed
haulouts is different; because of their smaller size, calves,
juveniles, and females are more susceptible to trampling injuries and
mortalities (Fay and Kelly 1980, pp. 226, 244). Females likely avoid
using terrestrial haulouts because their offspring are vulnerable to
predation and trampling (Nikiforov et al. 2007, pp. 1-2; Ovsyanikov et
al. 2007, pp. 1-3; Kochnev 2008, pp. 17-20; Kochnev et al. 2008, p.
When walruses are disturbed on ice floes, escape into the water is
relatively easy because fewer animals are concentrated in one area. In
comparison, aggregations of walruses on land are often very large in
number, densely packed, and ``layered'' several animals deep (Nikiforov
et al. 2007, p. 2). The presence of some large males in groups using
Chukchi Sea coastal haulouts increases the danger to calves, juveniles,
and females. Consequently, the probability of direct mortality or
injury due to trampling during stampedes is greater at terrestrial
haulouts than it is on pack ice (USFWS 1994, p. 12). Also, whether on
ice or land, calves may be abandoned as a result of disturbance to a
haulout (Fay et al. 1984, p. 118).
In addition, sources of disturbance are expected to be greater at
terrestrial haulouts than in offshore pack ice habitats, because the
level of human activity such as hunting, fishing, boating, and air
traffic is far greater along the coast. Haulout abandonment has been
documented from these sources (Fay et al. 1984; p. 114; Kochnev 2004,
pp. 285-286). There is also a greater chance of disturbance from
terrestrial animals (Kochnev 2004, p. 286). As sea ice declines, and
both polar bears and walruses are increasingly forced onto land
bordering the Chukchi Sea, we anticipate that there will be greater
interaction between the two species, especially during the summer. We
expect that one outcome of increased interactions will be increased
walrus mortality due to predation (discussed below). Of equal, or more
importance than predation is the disturbance caused at a haulout
through the arrival or presence of a polar bear, which can cause
stampeding. Repeated stampeding also increases energy expenditure and
stress levels, and may cause walruses to abandon the haulout (COSEWIC
2006, p. 25).
Losses that can occur when large numbers of walruses use
terrestrial haulouts are illustrated by observations in 2007, along the
coast of Chukotka, Russia. In response to summer sea-ice loss in 2007,
walruses began to arrive at coastal haulouts in July, a month earlier
than previously recorded (Kochnev 2008, pp. 17-20). Coastal
aggregations ranged in size from 4,500 up to 40,000 animals (Ovsyanikov
et al. 2007, pp. 1-2; Kochnev 2008, p. 17-20, Kavry et al. 2008, p.
248-251). Hunters from the Russian coastal villages of Vankarem and
Ryrkaipii reported more than 1,000 walrus carcasses (mostly calves of
the year and aborted fetuses) at coastal haulouts near the communities
in September 2007 (Nikiforov et al. 2007, p. 1; Kochnev 2008, pp. 17-
20). Noting the near absence of calves amongst the remaining animals,
Kochnev (2008, pp. 17-20) estimated that most of the 2007 cohort using
the site had been lost. Approximately 1,500 walrus carcasses
(predominately adult females) were also reported near Cape Dezhnev in
late October (Kochnev 2007, pers. comm.). Russian investigators
estimate that between 3,000 and 10,000 animals died along the Chukotka
coastline during the summer and fall of 2007, primarily from trampling
associated with disturbance events at the haulouts (Kochnev 2010, pers.
Relatively few large mortality events at coastal haulouts have been
documented in the past, but they have occurred (Fay 1982, p. 226). For
example, Fay and Kelly (1980, p. 230) examined several hundred walrus
carcasses at coastal haulouts on St. Lawrence Island and the Punuk
Islands in the fall of 1978. Approximately 15 percent of those
carcasses were aborted fetuses, 24 percent were calves, and the others
were older animals (mostly females) ranging in age from 1 to 37 years
old. The principal cause of death was trampling, possibly from
disturbance-related stampedes or battling bulls. As walruses become
increasingly dependent on coastal haulouts, interactions with humans
and predators are expected to increase and mortality events are likely
to become increasingly common. Long-term or chronic levels of
disturbance related mortalities at coastal haulouts are likely to have
a more significant population effect over time.
We recognize that Atlantic walruses (including females and calves)
utilize coastal haulouts to a greater extent than Pacific walruses,
foraging from shore along a relatively narrow coastal shelf; a
situation that is similar to what Pacific walrus may experience in the
future during ice-free months in the Chukchi Sea. However, Atlantic
walrus occupy an area with abundant remote islands that are free or
nearly free from disturbance from humans or terrestrial mammals. In
essence, their insular habitats function in a manner analogous to the
pack ice of the Pacific walrus, providing a refugium from disturbance.
In contrast, when Pacific walruses are restricted to terrestrial
haulouts, they face disturbance from a variety of terrestrial predators
and scavengers, including bears, wolverines, wolves, and feral dogs,
and higher levels of anthropogenic disturbances, because their haulouts
are at the edge of continental land masses and there are very few
islands in the Bering and Chukchi Seas. Sea ice, which has typically
acted as a refugium from disturbance for Pacific walruses, particularly
for females and young in the Chukchi Sea, will be lost entirely, or
almost entirely, for increasingly long time periods annually in the
foreseeable future. Therefore, although use of coastal haulouts is a
form of adaptability available to Pacific walruses, it comes with
negative impacts that are not associated with coastal haulouts for
In summary, we anticipate that Pacific walruses will become
increasingly dependent on coastal haulouts as sea ice retreats earlier
off the continental shelf and the Bering and Chukchi Seas become ice-
free for increasingly longer periods of time. The protection normally
provided to females and calves by the dispersal of smaller groups of
animals across a wide expanse of sea ice will be lost during periods of
ice-free or nearly ice-free conditions. Significant mortality events
from trampling have been documented at large haulouts, and we
anticipate that they will continue with much greater frequency into the
foreseeable future, resulting in increased mortality, particularly of
calves and females. Therefore, we conclude that disturbances and
trampling at haulouts is a threat to the Pacific walrus now and in the
Increased Vulnerability to Predation and Hunting
As Pacific walruses become more dependent on coastal haulouts, they
will become more susceptible to predation and hunting (Kochnev 2004, p.
286). Although hunting and predation are discussed separately below
(see Factors B and C, respectively), we also consider them here due to
their relationship to increased loss of sea-ice habitat.
Because of their large size and tusks, adult walruses are much less
susceptible to predation than are young animals or females. Females
likely avoid using terrestrial haulouts because their offspring are
vulnerable to predation (Kochnev 2004, p. 286; Ovsyanikov et al. 2007,
pp. 1-4; Kelly 2009, p. 302). Apparently, some polar bear routinely
rush herds to cause a stampede, expecting that some calves will be left
behind (Nikulin 1941; Popove 1958, 1960; as cited in Fay et al. 1984,
p. 119). As sea ice declines in the foreseeable future, increased use
of terrestrial habitats by both polar bears and walruses will likely
lead to increased interaction between them, and most likely an increase
in mortality, particularly of calves. We conclude that loss of sea ice,
which will force increased overlap between these two species, will
increase mortality from polar bears through direct take or indirect
take due to trampling during stampedes. See the section on predation in
Factor C below, for further information.
Large concentrations of walruses on shore for longer periods of
time could result in increased harvest levels if the terrestrial
haulouts form near coastal villages and environmental conditions allow
access to haulouts. Kochnev (2004, pp. 285-286) notes that many of the
haulouts along the Chukotka coast are situated near coastal villages,
and hunting activities at the haulouts can result in stampedes and
cause movements from one haulout to another. Some communities in
Chukotka situated in close proximity to the new haulouts have responded
by developing hunting restrictions to limit disturbances to resting
animals (Patrol 2008, p. 1; Kavry 2010, pers. comm.; Kochnev 2010 pers.
comm.). See the section on Subsistence Hunting in Factor B below, for
Summary of the Effects of Sea-Ice Loss on Pacific Walruses
The Pacific walrus is an ice-dependent species. Changes in the
extent, volume, and timing of the sea-ice melt and onset of freezing in
the Bering and Chukchi Seas have been documented and described earlier
in this finding, there are reliable projections that more extensive
changes will occur in the foreseeable future. We expect these changes
in sea ice will cause significant changes in the distribution and
habitat-use patterns of Pacific walruses. At this time we anticipate
that breeding behavior in winter and calving in the early spring will
not be impacted by expected changes to sea-ice conditions, although the
locations where these events occur will most likely change as the
location of available sea ice shifts to the north.
With the loss of summer sea ice, the most obvious change, which has
already been observed, will be a greater dependence on terrestrial
haulouts by both sexes and all age groups. Although walruses of both
sexes are capable of using terrestrial haulouts, historically, adult
males have used terrestrial haulouts, particularly in the Bering Sea,
to a much greater extent than females, calves, and juveniles. The loss
of summer sea ice means that walruses of both sexes, but females and
their young in particular, will be using coastal haulouts for longer
periods of time. This change is particularly notable in the Chukchi
Sea, which has historically had sufficient sea ice in the summer so
that females and calves could remain over the shallow continental shelf
throughout the summer. Since approximately 2005, the Chukchi Sea has
become ice-free or nearly so during part of the summer. This condition
is projected to increase over time, and may occur faster than forecast.
The consequences of this shift from sea ice to increasing use of land
include: Risk of localized prey depletion; increased energetic costs to
reach prey, resulting in decreased body condition; calf abandonment;
increased mortality from stampedes, especially to females, juveniles,
and calves; and potentially increased exposure to predation and
hunting. These events are expected to reduce survivorship.
As large numbers of animals are concentrated at coastal haulouts,
may be locally depleted, and greater distances will be required to
obtain it. Although males at haulouts in the Bering Sea function for
several months each year from terrestrial haulouts, females with calves
do not typically use terrestrial haulouts, and we expect the loss of
sea ice to have a greater impact on them through the higher energetic
cost of obtaining food. It is likely that these factors will lead to a
population decline over time, as fewer walruses can be supported by the
resources available from terrestrial haulouts. In the foreseeable
future, as the duration of ice-free periods over offshore continental
shelf regions of the Chukchi Sea increases from 1 to up to 5 months
(July through November), we expect the effects of prey depletion near
terrestrial haulouts will be heightened.
Periodic ice-free conditions, as are currently occurring, are
expected to lead to higher mortality rates, primarily through trampling
at haulouts when walruses congregate in large numbers. Although of
concern, if these events happen sporadically, as has been the case in
the past, the population may be able to recover between harsh years.
Although trampling mortalities have been documented in the past,
increasing use of terrestrial haulouts, the higher probability of
disturbance occurring at these haulouts, and in the near-term, the very
large numbers of animals using particular haulouts, increases the
probability that mortality from trampling will become a more regular
The increasing reliance of both polar bears and walruses on
terrestrial environments during ice free periods will likely result in
increased interactions between these two species. Polar bear predation
and associated disturbances at densely crowded coastal haulouts will
likely contribute to increased mortality levels, particularly of
calves, and may displace animals from preferred feeding areas. Hunting
activity at coastal haulouts does not appear to be a significant source
of mortality at the present time, but may become more of a factor in
the future. Local hunting restrictions at coastal haulouts have been
established in some communities in Chukotka to reduce disturbance-
related mortalities. The efficacy of efforts to mitigate sources of
anthropogenic disturbances at coastal walrus haulouts (including
hunting, boating and air traffic) will influence the degree to which
these factors will affect the Pacific walrus population. See Factors B
and C for further discussion on harvest and predation.
In conclusion, the loss of sea-ice habitat creates several
stressors on the Pacific walrus population. These stressors include:
localized prey depletion; increased energetic costs to reach prey,
resulting in decreased body condition; calf abandonment; increased
mortality from stampedes, especially to females, juveniles, and calves;
and increased exposure to predation and hunting. Because the Pacific
walrus range is large, and the animals are not all in the same place at
the same time, not all stressors are likely to affect the entire
population in a given year. However, all stressors represent potential
sources of increased mortality over the current condition, in which
these stressors occur infrequently. In the foreseeable future, as the
frequency of sea-ice loss in the summer and fall over the continental
shelves increases to a near-annual event and the length of time ice is
absent over the continental shelf increases from 1 to up to 5 months,
we expect the effects on walruses to be heightened and a greater
percentage of the population to be affected. Increased direct and
indirect mortality, particularly of calves, juveniles, and females,
will result in a declining population over time. Consequently, we
conclude that the destruction, modification, and curtailment of sea-ice
habitat is a threat to the Pacific walrus.
Outcome of Bayesian Network Analyses
Both the Service and USGS Bayesian network analyses (Garlich-Miller
et al. 2011; Jay et al. 2010b) considered changes in sea ice projected
through the 21st century. In both cases, the results indicate that
expected loss of sea ice is an important risk factor for Pacific walrus
population status over time. The USGS analysis deals more directly with
projected outcomes of the Pacific walrus population, including the
influence of sea-ice loss under different potential conditions (Jay et
al. 2010b, p. 40). For the normative sea ice run (see Jay et al. 2010b
for details), the probability of Pacific walruses becoming vulnerable,
rare, or extirpated increases over time, from approximately 22 percent
in 2050, to about 35 percent by 2075, and 40 percent in 2095 (Jay et
al. 2010b, p. 40). A ``worst case'' influence run was also evaluated.
For the worst case, model outputs were selected that have both the
greatest number of ice-free months and the least ice extent for the
Bering and Chukchi Seas and, therefore, represent the worst possible
situation. The outcome for the worst case influence run for sea ice
indicated that the probability of Pacific walruses becoming vulnerable,
rare, or extirpated approximately doubles at mid-century to 40 percent,
and reaches approximately 45 percent at 2075 (Jay et al. 2010b, p. 40).
At the end of 21st century, the probability of Pacific walruses
becoming vulnerable, rare, or extirpated in both the worst case
scenario and the normative run are essentially equal, at about 40
percent; an outcome that is due to the projected amount of sea-ice loss
being basically the same under the worst case and normative case by the
end of the century. We note, however, that the models and emissions
scenarios used by the IPCC in 2007 were the basis for this analysis.
Thus, it is possible that the ``worst case scenario'' reflects the
``faster than forecast'' loss of sea ice that may be realized if sea-
ice loss continues on the current downward trend that began in 1979
(National Snow and Ice Data Center, 2010). Regardless of which
trajectory will actually occur, the modeling efforts show that the
future status of the Pacific walrus is linked to sea ice, which already
is declining substantially, and more rapidly than previously projected.
Effects of Global Climate Change on Pacific Walrus Prey Species
The shallow, ice-covered waters of the Bering and Chukchi Seas
provide habitat that supports some of the highest benthic biomass in
the world (Grebmeier et al. 2006a, p. 1461; Ray et al. 2006, p. 404).
Sea-ice algae, pelagic (open ocean) primary productivity, and the
benthos (organisms that live on or in the sea floor) are tightly linked
through the sedimentation of organic particles (Grebmeier et al. 2006b,
p. 339). Sea-ice algae provide a highly concentrated and high-quality
food source for plankton food webs in the spring, which translates to
high-quality food for the benthos such as clams (Grebmeier et al.
2006b, p. 339; McMahon et al. 2006, pp. 2-11; Gradinger 2009, p. 1211).
Because zooplankton, which also feed on the algae, have correspondingly
low populations at this time in the spring, much of the primary
productivity of algae falls to the sea floor, where it is available to
the benthic invertebrates (Grebmeier et al. 2006b, p. 339).
Spatial distribution and abundance in biomass in benthic habitat
across the Bering and Chukchi Seas is influenced by a variety of
ecological, oceanographic, and geomorphic features. In the subarctic
region of the Bering Sea (from the Bering Strait south to latitude 50
degrees), benthic organisms are preyed upon by demersal fish (living
near the bottom of the water column) and epifaunal invertebrates (those
organisms living on top of the sea floor rather than in it), whose
distribution is limited to the north by cold water (less than 0 [deg]C
resulting from seasonal sea-ice cover, forming a temperature-mediated
ecological boundary. In the absence of demersal fish and predatory
invertebrates, benthic-feeding whales, walrus, and sea-birds are the
primary consumers in the Arctic region of the Bering Sea (Grebmeier et
al. 2006b, pp. 1461-1463).
Within the Arctic region of the Bering Sea, marginal sea-ice zones
and areas of polynyas appear to be ``hot spots'' of high benthic
diversity and productivity (Grebmeier and Cooper 1995, p. 4439).
Benthic biomass is particularly high in the northern Bering Sea, the
southern Chukchi Sea, and the Gulf of Anadyr. However, the high
diversity and productivity of the benthic communities is not seen in
the Southern Beaufort Sea shelf and areas of the eastern Chukchi Sea,
which are influenced by the nutrient-poor Alaska coastal current (Fay
et al. 1977, p. 12; Grebmeier et al. 1989, p. 261; Feder et al. 1994,
p. 176; Smith et al. 1995, p. 243; Grebmeier et al. 2006b, p. 346;
Bluhm and Gradinger 2008, p. 2).
For the last several decades, surface air temperatures throughout
the Arctic, over both land and water, have warmed at a rate that
exceeds the global average, and they are projected to continue on that
path (Comiso and Parkinson 2004, pp. 38-39; Christensen et al. 2007, p.
904; Lawrence et al. 2008, p. 1; Serreze et al. 2009, pp. 11-12). In
addition, the subsurface and surface waters of the Arctic Ocean and
surrounding seas, including the Bering and Chukchi Seas have warmed
(Steele and Boyd 1998, p. 10419; Zhang et al. 1998, p. 1745; Overland
and Stabeno 2004, p. 309; Stabeno et al. 2007, pp. 2607-2608; Steele et
al. 2008, p. 1; Mueter et al. 2009, p. 96). There are several
mechanisms working in concert to cause these increases in ocean
temperature, including: Warmer air temperatures (Comiso and Parkinson
2004, pp. 38-39; Overland and Stabeno 2004, p. 310), an increase in the
heat carried by currents entering the Arctic from both the Atlantic
(Drinkwater et al., p. 25; Zhang et al. 1998, p. 1745) and Pacific
Oceans (Stabeno et al. 2007, p. 2599; Woodgate et al. 2010, p. 1-5),
and a shorter ice season, which decreases the albedo (reflective
property) of ice and snow (Comiso and Parkinson 2004, p. 43; Moline et
al. 2008, p. 271; Markus et al. 2009, p. 13). Due to their biological
characteristics which include tolerance of considerable variations in
temperature, direct effects to walrus are not anticipated with warmer
ocean temperatures. Nevertheless, changes in the thermal dynamics of
ocean conditions may affect walrus indirectly through impacts to their
prey base. Changes to density, abundance, distribution, food quality,
and species of benthic invertebrates may occur primarily through
changes in habitat related to sea ice.
Walruses are the top predator of a relatively simple food web in
which the primary constituents are bacteria, sea-ice algae,
phytoplankton (tiny floating plants), and benthic invertebrates (Horner
1976, p. 179; Lowry and Frost 1981, p. 820; Grebmeier and Dunton 2000,
p. 65; Dunton et al. 2006, p. 370; Aydin and Mueter 2007, p. 2507). Sea
ice is important to the Arctic food webs because: (1) It is a substrate
for ice algae (Horner 1976, pp. 168-171; Kern and Carey Jr. 1983, p.
161; Grainger et al. 1985, pp. 25-27; Melnikov 2000, pp. 79-81;
Gradinger 2009, p. 1201); (2) it influences nutrient supply and
phytoplankton bloom dynamics (Lovvorn et al. 2005, p. 136); and (3) it
determines the extent of the cold-water pool on the southern Bering
shelf (Aydin and Mueter 2007, p. 2503; Coyle et al. 2007, p. 2900;
Stabeno et al. 2007, p. 2615; Mueter and Litzow 2008, p. 309).
In the spring, ice algae form up to a 1-cm- (0.4-in-) thick layer
on the underside of the ice, but are also found at the ice surface and
throughout the ice matrix (Horner 1976, pp. 168-171; Cota and Horne
1989, p. 111; Gradinger et al. 2005, p. 176; Gradinger 2009, p. 1207).
Ice algae can be released into the water through water turbulence below
the ice, through brine drainage through the ice, or when the algal mats
are sloughed as the ice melts (Cota and Horne 1989, p. 117; Renaud et
al. 2007, p. 7). As noted above, sea-ice algae provide a highly
concentrated food source for the benthos and the plankton (organisms
that float or drift in the water) food web that is initiated once the
ice melts (Grebmeier et al. 2006b, p.339; McMahon et al. 2006, pp. 1-2;
Renaud et al. 2007, pp. 8-9; Gradinger 2009, p. 1211). Areas of high
primary productivity support areas of high invertebrate mass, which is
food for walruses (Grebmeier and McRoy 1989, p. 87; Grebmeier et al.
2006b, p. 332; Bluhm and Gradinger 2008, p. S87).
Spring ice melt plays an important role in the timing, amount, and
fate of primary production over the Bering Sea shelf, with late melting
(as occurs now) leading to greater delivery of food from primary
production to the benthos and earlier melting (as is projected to occur
in the future) contributing food primarily to the pelagic system (Aydin
and Mueter 2007, p. 2505; Coyle et al. 2007, p. 2901). When ice is
present from late March to May (as occurs now), cold surface
temperatures, thinning ice, and low-salinity melt water suppress wind
mixing, and cause the water column to stratify, creating conditions
that promote a phytoplankton bloom. The burst of phytoplankton, seeded
in part by ice algae, persists until ocean nutrients are drawn down.
Because it is early in the season and water temperatures are cold,
zooplankton populations are still low. Consequently, the pulse of
phytoplankton production is not consumed by zooplankton, but instead
sinks to the sea floor, where it provides abundant food for the benthos
(Coyle and Cooney 1988, p. 177; Coyle and Pinchuk 2002, p. 177; Hunt
and Stabeno 2002, p. 11; Lovvorn et al. 2005, p. 136; Renaud et al.
2007, p. 9). Blooms form a 20- to 50-km- (12-31 mi-) wide belt off the
ice edge and progress north as the ice melts, creating a zone of high
productivity. In colder years in the Bering Sea, when the ice extends
to the shelf edge, there is greater nutrient resupply through shelf-
edge eddies and tidal mixing, creating a longer spring bloom (Tynan and
DeMaster 1997, pp. 314-315).
The blooms that occur near the ice edge make up approximately 50 to
65 percent of the total primary production in Arctic waters (Coyle and
Pinchuk 2002, p. 188; Bluhm and Gradinger 2008, p. S84). High benthic
abundance and biomass correspond to areas with high deposition of
phytodetritus (dead algae) (Grebmeier et al. 1989, pp. 253-254;
Grebmeier and McRoy 1989, p. 79; Tynan and DeMaster 1997, p. 315).
Regions with the highest masses of benthic invertebrates occur in the
northern Bering Sea southwest of St. Lawrence Island, Alaska; in the
central Gulf of Anadyr, Russia, north and south of the Bering Strait;
at a few offshore sites in the East Siberian Sea; and in the northeast
sector of the Chukchi Sea (Grebmeier and Dunton 2000, p. 61; Dunton et
al. 2005, pp. 3468, 3472; Carmack et al. 2006, p. 165; Grebmeier et al.
2006b, pp. 346-351; Aydin and Mueter 2007, pp. 2505-2506; Bluhm and
Gradinger 2008, p. S86). As noted above, the biomass of benthic
invertebrates is much less in the eastern Chukchi Sea, which is under
the influence of the nutrient-poor Alaska Coastal Current (Dunton et
al. 2006, p. 369).
When the ice melts early (before mid-March, as projected for the
future), conditions that promote the phytoplankton bloom do not occur
until late May or June (Stabeno et al. 2007, p. 2612). The difference
in timing is important, because when the bloom
occurs later in the spring the surface water temperatures are 2.2
[deg]C (3.6 [deg]F) to more than 5 [deg]C (9.4 [deg]F) warmer (Hunt and
Stabeno 2002, p. 11); this, in turn, is an important influence on the
metabolism of zooplankton. In cold temperatures, zooplankton consume
less than 2 percent of the phytoplankton production (Coyle and Cooney
1988, pp. 303-305; Coyle and Pinchuk 2002, p. 191). Warmer temperatures
result in increased zooplankton growth rates, reduction in their time
to maturity, and increased production rates (Coyle and Pinchuk 2002, p.
177; Hunt and Stabeno 2002, pp. 12-14). Zooplankton are efficient
predators of phytoplankton, and when they are abundant, they can remove
nearly all the phytoplankton available (Coyle and Pinchuk 2002, p.
191). Zooplankton are the primary food for walleye pollock (Theragra
chalcogramma) and other planktivorous fishes (Hunt and Stabeno 2002,
pp. 14-15). Consequently, when zooplankton populations are high,
instead of the primary production being transmitted to the benthos, it
becomes tied up in pelagic food webs. While this may be beneficial for
fish-eating mammals, it reduces the amount of food delivered to the
benthos and, thus, may reduce the amount of prey available to walrus
(Tynan and DeMaster 1997, p.316; Carmack et al. 2006, p. 169; Grebmeier
et al. 2006a, p. 1462). Most models project that sea-ice melt in the
Bering Sea will occur increasingly early in the future, and will be 1
month earlier by the end of the century (Douglas 2010, p. 12). This is
consistent with recent trends over the past two decades, and
particularly in the past few years. Based on our current understanding
of food web dynamics in the Bering Sea, this shift in timing would
favor a shift to pelagic food webs over benthic production,
consequently reducing the amount of prey available to walrus.
The importance of ice algae is not only in its role in seeding the
spring phytoplankton bloom, but also in its nutritional value. As food
supply to the benthos is highly seasonal, synchrony of reproduction
with algal inputs insures adequate high-quality food for developing
larvae or juveniles of benthic organisms (Renaud et al. 2007, p. 9).
Ice algae have high concentrations of essential fatty acids, some of
which cannot be synthesized by benthic invertebrates and, therefore,
must be ingested in their diet (Arrigo and Thomas 2004, p. 477; Klein
Breteler et al. 2005, pp. 125-126; McMahon et al. 2006, pp. 2, 5).
Fatty acids in marine fauna play an integral role in physiological
processes, including reproduction (Klein Breteler et al. 2005, p. 126).
Because ice algae are a much better source of essential fatty acids
than phytoplankton, a loss in sea ice could change the quality of food
supplied to areas that currently support high levels of benthic
biomass. These changes may affect the success of invertebrate
reproduction and recruitment, which, in turn, may affect the quantity
and quality of food available to walrus (Witbaard et al. 2003, p. 81;
McMahon et al. 2006, pp. 10-12). By the end of the century, the March
(winter maximum) extent of sea ice is projected to be approximately
half of contemporary conditions (Douglas 2010, p. 8). We expect ice
algae will persist where ice is present; however, because of the
reduced ice extent, current areas of high benthic productivity may be
reduced or shift northward.
The eastern and western Bering Sea shelves are fueled by nutrient-
rich water supplied from the deep water of the Bering Sea (Sambrotto et
al. 1984, pp. 1148-1149; Springer et al. 1996, p. 205). Concentrations
of nitrate, phosphate, and silicate are among the highest recorded in
the world's oceans and contribute to the high benthic productivity
(Sambrotto et al. 1984, p. 1148; Grebmeier et al. 2006a, p. 1461; Aydin
and Mueter 2007, p. 2504). High productivity on the northern Bering-
Chukchi shelf is supported by the delivery of nutrient-rich water via
the Anadyr Current that flows along the western edge of the Bering Sea
and through the Bering Strait (Springer et al. 1996, p. 206; Aydin and
Mueter 2007, p. 2504). Thus, the movement of highly productive water
onto the northern Bering Sea shelf supports persistent hot spots of
high benthic productivity, which in turn support large populations of
benthic-feeding birds, walrus, and gray whales (Aydin and Mueter 2007,
p. 2506). This contrasts with the southern subarctic region of the
Bering Sea, which is south of the current range of the Pacific walrus,
where the benthic mass is largely consumed by upper tropic-level
demersal fish and epifaunal invertebrates whose northern distribution
is limited by a pool of cold, near-freezing water in the northern
region of the Bering Sea.
Benthic productivity on the northern Bering Sea shelf has decreased
over the last two decades, coincident with a reduction of northward
flow of the Anadyr current through the Bering Strait (Grebmeier et al.
2006a, p. 1462). Because of recent warming trends, the northern Bering
Sea shelf may be undergoing a transition from an Arctic to a more
subarctic ecosystem with a reduction in benthic prey populations and an
increase in fish populations (Overland and Stabeno 2004, p. 310;
Grebmeier et al. 2006a, pp. 1462-1463). The Bering Sea is a transition
area between Arctic and subarctic ecosystems, with the boundary between
the two loosely concurrent with the extent of the winter sea-ice cover
(Overland and Stabeno 2004, p. 309). In the eastern Bering Sea,
reductions in sea ice have been responsible for shrinking a large
subsurface pool of cold water with water temperatures less than 2
[deg]C (3.6 [deg]F) (Stabeno et al. 2007, p. 2605; Mueter and Litzow
2008, p. 313). The southern edge of the cold pool, which defines the
boundary region between the Arctic and subarctic communities, has
retreated approximately 230 km (143 mi) north since the early 1980s
(Mueter and Litzow 2008, p. 316).
The northward expansion of warmer water has resulted in an increase
in pelagic species as subarctic fauna have colonized newly favorable
habitats (Overland and Stabeno 2004, p. 309; Mueter and Litzow 2008,
pp. 316-317). Walleye pollock, a species common in the subarctic, which
avoid temperatures less than 2[deg] C (3.6 [deg]F), have now moved
northward into the former Arctic zone. Arctic cod (Boreogadus saida),
which prefer cold temperatures, have also moved north to remain in
colder temperatures (Stabeno et al. 2007, p. 2605). Because of the
redistribution of these species, benthic fauna will be facing a new set
of predators (Coyle et al. 2007, pp. 2901-2902). The evidence suggests
that warming on the Bering Sea shelf could alter patterns of energy
flow and food web relationships in the benthic invertebrate community,
leading to overall reductions in biomass of benthic invertebrates
(Coyle et al. 2007, p. 2902).
Continued changes in the extent, thickness, and timing of the melt
of sea ice are expected to create shifts in production and species
distributions (Overland and Stabeno 2004, p. 316). Because some
residents of the benthos are very long lived, it may take many years of
monitoring to observe change (Coyle et al. 2007, p. 2902). Many
simultaneous changes (e.g., ocean currents, temperature, sea-ice
extent, and wind patterns) are occurring in walrus-occupied habitats,
and thus may impact walrus' prey base. Rapid warming might cause a
major restructuring of regional ecosystems (Carmack and Wassmann 2006,
p. 474; Mackenzie and Schiedek 2007, p. 1344). Mobile species such as
fishes have the ability to move to areas of thermal preference and
follow key forage species (Mueter et al. 2009, p. 106); immobile
species such as bivalves must cope with the conditions where they are.
Projections by Douglas (2010, pp. 7, 23) indicate that the March
(yearly maximum) sea-ice extent in the Bering Sea will be about 25
percent less than the 1979-1988 average by mid-century, and 60 percent
less by the end of the century. In addition, spring melt of sea ice
will occur increasingly earlier, and on average will be one month
sooner by the end of the century (Douglas 2010, p. 8). As described
above, the earlier spring melt may lead to a change in the food web
dynamics that favors pelagic predators, which feed on zooplankton, over
the delivery of high quantities of quality food to benthic
invertebrates. In addition, reductions in the extent of the winter sea-
ice cover may lead to a further or more permanent expansion of the
subarctic ecosystem northward into the Arctic. Although there is
uncertainty about the specific consequences of these changes, the best
available scientific information suggests that because of the likely
decreases in the quantity and quality of food delivered to benthic
invertebrates, and because of a potential increase in predators from
the south, the amount and distribution of preferred prey (bivalves)
available to walrus in the Bering Sea will likely decrease in the
foreseeable future as a result of the loss of sea ice and ocean
warming. The extent to which this decrease may result in a curtailment
of the range of the Pacific walrus or limit the walrus population in
the future is unknown, and at this time we do not have sufficient
information to predict it with reliability. The implications of the
available information, however, are that impacts may include
modification of habitat that could contribute to a reduction in the
range of the Pacific walrus at the southern edge of its current
distribution, as well as a possible reduction in the walrus population
because of reduced prey. Although our conclusion is based on the best
available science, we recognize that its validity rests on ecological
hypotheses that are currently being tested.
Since the beginning of the industrial revolution in the mid-18th
century, the release of carbon dioxide (CO2) from human
activities (``anthropogenic CO2'') has resulted in an
increase in atmospheric CO2 concentrations, from
approximately 280 to approximately 390 ppm currently, with 30 percent
of the increase occurring in the last three decades (NOAA, http://www.climatewatch.noaa.gov/2009/articlesclimate-change-atmospheric-carbon-dioxide, downloaded 20 July 2010).
The global atmospheric concentration of CO2 is now
higher than experienced for more than 800,000 years (L[uuml]thi et al.
2008, p. 379; Scripps 2011, p. 4). Over the industrial era, the ocean
has been a sink for anthropogenic carbon emissions, absorbing about
one-third of the atmospheric CO2 (Feely et al. 2004, p. 362;
Canadell et al. 2007, pp. 18867-18868). When CO2 is absorbed
by seawater, chemical reactions occur that reduce seawater pH (a
measure of acidity) and the concentration of carbonate ions, in a
process known as ``ocean acidification.''
Ocean acidification is a consequence of rising atmospheric
CO2 levels (The Royal Society 2005, p.1; Doney et al. 2008,
p. 170). Seawater carbonate chemistry is governed by a series of
chemical reactions (CO2 dissolution, acid/base chemistry,
and calcium carbonate dissolution) and biologically mediated reactions
(photosynthesis, respiration, and calcium carbonate precipitation)
(Wootton et al. 2008, p. 18848; Bates and Mathis 2009, p. 2450). The
marine carbonate reactions allow the ocean to absorb CO2 in
excess of potential uptake based on carbon dioxide solubility alone
(Denman et al. 2007, p. 529). Consequently, the pH of ocean surface
waters has already decreased (become more acid) by about 0.1 units
since the beginning of the industrial revolution (Caldeira and Wickett,
2003, p. 365; Orr et al. 2005, p. 681).
The absorption of carbon dioxide by seawater changes the chemical
equilibrium of the inorganic carbon system and reduces the
concentration of carbonate ions. Carbonate ions are required by
organisms like clams, snails, crabs, and corals to produce calcium
carbonate, the primary component of their shells and skeletons.
Decreasing concentrations of carbonate ions may place these species at
risk (Green et al. 2004, p. 729-730; Orr et al. 2005, p. 685; Gazeau et
al. 2006 p. 1; Fabry et al. 2008, p. 419-420; Comeau et al. 2009, p.
1877; Ellis et al. 2009, p. 41). Two forms of calcium carbonate
produced by marine organisms are aragonite and calcite. Aragonite,
which is 50 percent more soluble in seawater than calcite, is of
greatest importance in the Arctic region because clams, mussels,
snails, crustaceans, and some zooplankton use aragonite in their shells
and skeletons (Fritz 2001, p. 53; Fabry et al. 2008, p. 417; Steinacher
et al. 2009, p. 515).
When seawater is saturated with aragonite or calcite, the formation
of shells and skeletons is favored; when undersaturated, the seawater
becomes corrosive to these structures and it becomes physiologically
more difficult for organisms to construct them (Orr et al. 2005, p.
685; Gazeau et al. 2007, p. 2-5; Fabry et al. 2008, p. 415; Talmage and
Gobler 2009, p. 2076; Findlay et al. 2010, pp. 680-681). The waters of
the Arctic Ocean and adjacent seas are among the most vulnerable to
ocean acidification, with undersaturation of aragonite projected to
occur locally within a decade (Orr et al. 2005, p. 683; Chierici and
Fransson 2009, pp. 4972-4973; Steinacher et al. 2009, p. 522). To date,
aragonite saturation has decreased in the top 50 m (164 ft) in the
Canadian Basin (Yamamoto-Kawai et al. 2009, p. 1099), and under-
saturated waters have been documented on the Mackenzie shelf (Chierici
and Fransson 2009, p. 4974), Chukchi Sea (Bates and Mathis 2009, p.
2441), and Bering Sea (Fabry et al. 2009, p. 164).
Factors that contribute to undersaturation of seawater with
aragonite or calcite are: upwelling of carbon dioxide-rich subsurface
waters; increased carbon dioxide concentrations from anthropogenic
CO2 uptake; cold water temperatures; and fresher, less
saline water (Feely et al. 2008, p. 1491; Chierici and Fransson 2009,
p. 4966; Yamamoto-Kawai et al. 2009, p. 1099). The loss of sea ice
(causing greater ocean surface to be exposed to the atmosphere), the
retreat of the ice edge past the continental shelf break that favors
upwelling, increased river runoff, and increased sea ice and glacial
melt are forces that favor undersaturation (Yamamoto-Kawai et al. 2009,
pp. 1099-1100; Bates and Mathis 2009, pp. 2446, 2449-2450). The
projected increase of 3 to 5 months of ice-free conditions in the
Bering and Chukchi Seas by Douglas (2010, p. 7) indicates the potential
for increased CO2 absorption in the Arctic over the next
century beyond what would occur from predicted CO2 increases
alone. However, there are opposing forces that may mitigate
undersaturation to some extent, including photosynthesis by
phytoplankton that may increase with reduced sea ice, and warmer ocean
temperatures (Bates and Mathis 2009, p. 2451). However, according to
Steinacher et al. (2009, p. 530), the question is not whether
undersaturation will occur in the Arctic, but how large an area will be
affected, how many months of the year it will occur, and how large its
Because acid-base balance is critical for all organisms, changes in
carbon dioxide concentrations and pH can affect reproduction, larval
development, growth, behavior, and survival of all marine organisms
(Green et al. 1998, p.
23; Kurihara and Shirayama 2004, pp. 163-165; Berge et al. 2006, p.
685; Fabry et al. 2008, pp. 420-422; Kurihara 2008, pp. 277-282;
P[ouml]rtner 2008, pp. 209-211; Ellis et al. 2009, pp. 44-45; Talmage
and Gobler 2009, p. 2076; Findlay et al. 2010, pp. 680-681).
P[ouml]rtner (2008, p. 211) suggests that heavily calcified marine
groups may be among those with the poorest capacity to regulate acid-
base status. Although some animals have been shown to be able to form a
shell in undersaturated conditions, it comes at an energetic cost which
may translate to reduced growth rate (Talmage and Gobler 2009, p. 2075;
Findlay et al. 2010, p. 679; Gazeau et al. 2010, p. 2938), muscle
wastage (P[ouml]rtner 2008, p. 210), or potentially reduced
reproductive output. Because juvenile bivalves have high mortality
rates, if aragonite undersaturation inhibits planktonic larval bivalves
from constructing shells (Kurihara 2008, p. 277) or inhibits them from
settling (Hunt and Scheibling 1997, pp. 274, 278; Green et al. 1998, p.
26; Green et al. 2004, p. 730; Kurihara 2008, p. 278), the increased
mortality would likely have a negative effect on bivalve populations.
The effects of ocean acidification on walrus may be through changes
in their prey base, or indirectly through changes in the food chain
upon which their prey depend. Walruses forage in large part on
calcifying invertebrates (Ray et al. 2006, pp. 407-409; Sheffield and
Grebmeier 2009, pp. 767-768; also see discussion of diet, above).
Aragonite undersaturation has been documented in the area occupied by
Pacific walrus (Bates and Mathis 2009, p. 2441; Fabry et al. 2009, p.
164), and it is projected to become widespread in the future
(Steinacher 2009, p. 530; Fr[ouml]licher and Joos 2010, pp. 13-14).
Thus, it is possible that mollusks and other calcifying organisms may
be negatively affected through a variety of mechanisms, described
above. While the effects of observed ocean acidification on the marine
organisms are not yet documented, the progressive acidification of
oceans is expected to have negative impacts on marine shell-forming
organisms in the future (The Royal Society 2005, p. 21; Denman et al.
2007, p. 533; Doney et al. 2009, p. 176; Kroeker et al. 2010, p. 9).
Uncertainty regarding the general effects of ocean acidification
has been summarized by the Royal Society (2005, p. 23): ``Organisms
will continue to live in the oceans wherever nutrients and light are
available, even under conditions arising from ocean acidification.
However, from the data available, it is not known if organisms at the
various levels in the food web will be able to adapt or if one species
will replace another. It is also not possible to predict what impacts
this will have on the community structure and ultimately if it will
affect the services that the ecosystems provide.'' Consequently,
although we recognize that effects to calcifying organisms, which are
important prey items for Pacific walrus, will likely occur in the
foreseeable future from ocean acidification, we do not know which
species may be able to adapt and thrive, or the ability of the walrus
to depend on alternative prey items. As noted in the introduction, the
prey base of walrus includes over 100 taxa of benthic invertebrates
from all major phyla (Sheffield and Grebmeier 2009, pp. 761-777).
Although walruses are highly adapted for obtaining bivalves, they also
have the potential to switch to other prey items if bivalves and other
calcifying invertebrate populations decline. Whether other prey items
would fulfill walrus nutritional needs over their life span is unknown
(Sheffield and Grebmeier 2009, p. 770), and there also is uncertainty
about the extent to which other suitable non-bivalve prey might be
available, due to uncertainty about the effects of ocean acidification
and the effects of ocean warming.
Both Bayesian network models (Garlich-Miller et al. 2010; Jay et
al. 2010b) indicate that ocean warming and ocean acidification are
likely to have little effect on Pacific walrus future status, but these
conclusions were primarily because of the high degree of uncertainty
associated with these factors. As described above, our analysis
indicates that earlier melting of ice in the spring, a decreased extent
of ice in winter and spring, and warming of the ocean may lead to
changes in the distribution, quality, and quantity of food available to
Pacific walrus over time. In addition, in the future, ocean
acidification has the potential to have a negative impact on calcifying
organisms, which currently represent a large portion of the walrus'
diet. The best available science does not indicate that either of these
factors will have a positive impact on the availability, quality, or
quantity of food available to the walrus in the future. However, we are
also unable to predict to what extent these factors may limit the
Pacific walrus population in the future, in terms of reduction in its
range or abundance, or the extent to which the walrus may be able to
adapt to a changing prey base. Therefore, we conclude that ocean
warming and ocean acidification are not threats to the Pacific walrus
now or in the foreseeable future, although we acknowledge that the
general indications are that impacts appear more likely to be negative
than positive or neutral.
Summary of Factor A
We have analyzed the effects of the loss of sea ice, ocean warming,
and ocean acidification as related to the present or threatened
destruction, modification, or curtailment of the habitat or range of
the Pacific walrus. Although we are concerned about the changes to
walrus prey that may occur from ocean acidification and warming, and
theoretically we understand how those stressors might operate, ocean
dynamics are very complex and the changing conditions and related
outcomes for these stressors are too uncertain at this time for us to
conclude that these stressors are a threat to Pacific walrus now or in
the foreseeable future.
Because of the loss of sea ice, Pacific walruses will be forced to
rely on terrestrial haulouts to a greater and greater extent over time.
Although coastal haulouts have been traditionally used by males, in the
future both sexes and all ages will be restricted to coastal habitats
for a much greater period of time. This will expose all individuals,
but especially calves and females to increased stress, energy
expenditure, and death or injury from disturbance-caused stampedes from
terrestrial haulouts. Calf abandonment, and increased energy
expenditure for females and calves is likely to occur from prey
depletion near terrestrial haulouts. Increased energy expenditure could
lead to decreased condition and decreased survival. In addition, there
may be a small increase in direct mortality or injury of calves and
females due to increased predation or hunting as a result of greater
use of terrestrial haulouts. Although some of these stressors are
acting on the population currently, we anticipate that their magnitude
will increase over time as sea-ice loss over the continental shelf
occurs more frequently and more extensively. Due to the projected
increases in sea-ice habitat loss and the resultant stressors
associated with increased dependence on coastal haulouts, as described
above, we do not anticipate the projected Pacific walrus population
decline to stabilize in the foreseeable future. Rather, the best
scientific information available leads to a conclusion that the Pacific
walrus will be increasingly at risk. Through our analysis, we have
concluded that loss of sea ice, with its concomitant changes to walrus
distribution and life-history
patterns, will lead to a population decline. Therefore, we conclude,
based on the best scientific and commercial data available, that the
present or threatened destruction, modification, or curtailment of its
habitat or range is a threat to Pacific walrus.
Factor B. Overutilization for Commercial, Recreational, Scientific, or
The following potential factors that may result in overutilization
of Pacific walrus are considered in this section: (1) Recreation,
scientific, or educational purposes; (2) U.S. import/export; (3)
commercial harvest; and (4) subsistence harvest. Under Factor A, we
also discuss the potential increase in subsistence hunting associated
with increasing dependence of Pacific walrus on coastal haulouts caused
by the loss of sea-ice habitat.
Recreation, Scientific, or Educational Purposes
Overutilization for recreational, scientific, or educational
purposes is currently not considered a threat to the Pacific walrus
population. Recreational (sport) hunting has been prohibited in the
United States since 1979. Russian legislation also prohibits sport
hunting of Pacific walruses. The Marine Mammal Protection Act of 1972,
as amended (16 U.S.C. 1361, et seq.) (MMPA), allows the Service to
issue a permit authorizing the take of walrus for scientific purposes
in the United States, provided that the research will further a bona
fide and necessary or desirable scientific purpose. The Service must
consider the benefits to be derived from the research and the effects
of the taking on the stock, and must consult with the public, experts
in the field, and the United States Marine Mammal Commission.
Similarly, any take for an educational purpose is allowed by the
MMPA only after rigorous review and with appropriate justification. No
permits authorizing the take of walrus for educational and public
display purposes have been requested in the United States since the
1990s. The Service has worked with the public display community to
place stranded animals, which the Service has determined cannot be
returned to the wild, at facilities for educational and public display
purposes. By placing stranded walruses, which would otherwise be
euthanized, at facilities that are able to care for and display the
animals, we believe needs for the domestic public display community in
the United States have been, and will continue to be, met. The Russian
Federation intermittently authorizes the taking of walrus from the wild
for scientific and educational purposes. For example, in 2009, a
collection permit was issued for take of up to 40 walrus calves from
the wild to be used for public display. This take was included in the
subsistence harvest quota, and is therefore considered sustainable. We
have no information that would lead us to believe this level of take
from the wild will increase in the foreseeable future.
Based on the above, we conclude that utilization of walrus for
recreational, scientific, or educational purposes is not a threat to
the Pacific walrus population. Protections and regulatory mechanisms in
both the United States and the Russian Federation have stopped
recreational hunting. In the United States, the MMPA has effectively
ensured that any removal for scientific or educational purposes has a
bona fide and necessary or desirable scientific basis. In the Russian
Federation, take for scientific or educational purposes is controlled
by a quota. We believe the United States and the Russian Federation
will continue to ensure that any future removal of walrus for
recreational, scientific, or educational purposes will be consistent
with the long-term conservation of the species. Therefore, we have
determined, based on the best scientific and commercial data available,
that the utilization of Pacific walrus for recreational, scientific, or
educational purposes is not a threat to the species now or in the
United States Import/Export
Based on data from the Service's Law Enforcement Management
Information System (LEMIS), in 2008 more than 16,000 walrus parts,
products, and derivatives (ivory jewelry, carvings, bone carvings,
ivory pieces, and tusks) were imported into or exported from the United
States. Over 98 percent of those specimens were from walrus that had
originated in the United States. Most of these specimens were
identified as fossilized bone and ivory shards, principally dug from
historic middens on St. Lawrence Island, or carvings from such.
Therefore, the harvest of the source animals predates adoption of the
MMPA in 1972, and does not represent a threat to the species.
Since the passage of the MMPA in 1972, ivory and bone can only be
exported from the United States after it has been legally harvested,
and substantially altered to qualify as an Alaska Native handicraft and
as a personal effect or as part of a cultural exchange. Trade in raw
post-MMPA walrus ivory is closely monitored by the Service through
existing import/export regulations (Garlich-Miller et al. 2011, Section
3.5.1 ``International Agreements'').
Most of the walrus parts imported into or exported from the United
States are derived from historic ivory and bone shards, and parts from
newly harvested walrus are subject to the MMPA requirements that limit
U.S. trade to Alaska Native handicrafts. Therefore, we have determined,
based on the best scientific and commercial data available, that United
States Import/Export is not considered to be a threat to the Pacific
walrus now or in the foreseeable future.
Commercial harvest of the Pacific walrus is prohibited in the U.S.,
and has not occurred in Russia since 1991 (see discussion below).
Pacific walrus ivory and meat was available on the commercial market
starting in the seventeenth century (Fay 1957, p. 435; Elliot 1982, p.
98). Since then, commercial harvest levels have varied in response to
population size and economic demand. Several of the larger reductions
in the Pacific walrus population have been attributed to unsustainable
harvest levels, largely driven by commercial hunting (Fay 1957, p. 437;
Bockstoce and Botkin 1982, p. 183). Harvest regulations enacted in the
United States and Russia in the 1950s and 1960s that reduced the size
of the harvest and provided protection to females and calves allowed
the population to recover and peak in the 1980s (Fay et al. 1989, p.
Commercial harvest of marine mammals in U.S. waters is currently
prohibited by the MMPA. Commercial harvest was last conducted in Russia
in 1991 (Garlich-Miller and Pungowiyi 1999, p. 59). Russian legislation
still allows for a commercial harvest, although a decree from the
Russian Fisheries Ministry allocating a commercial harvest quota would
be required prior to resumption of harvest (Kochnev 2010, pers. comm.).
Quota recommendations are determined by sustainable removal levels,
which are based on the total population and productivity estimates
(Garlich-Miller and Pungowiyi 1999 p. 32). Therefore, any potential
future commercial harvest in Russia is unlikely to become a threat to
Commercial hunting of Pacific walrus is banned in the United
States. Regulatory protections in the Russian Federation have been
effective in ensuring that any removal for commercial purposes is
long-term conservation of the species. Therefore, we have determined,
based on the best scientific and commercial data available, that
commercial harvest is not a threat to Pacific walrus either now or in
the foreseeable future.
Pacific walrus have been an important subsistence resource for
coastal Alaskan and Russian Natives for thousands of years (Ray 1975,
p. 10). In 1960, the State of Alaska restricted the subsistence harvest
of female walrus to seven per hunter per year in an effort to recover
the population from a reduced state. Concurrently, Russia also
implemented harvest quotas and prohibited shooting animals in the water
(to reduce lost animals) (Fay et al. 1989, p. 4). In 1961, the State of
Alaska further reduced the quota to five females per hunter per year,
still allowing an unlimited number of males to be hunted. The limit of
five adult females per hunter remained in effect until 1972, when
passage of the Marine Mammal Protection Act transferred management
responsibility to Federal control (Fay et al. 1997, p. 548). As a
result of reducing the numbers of females harvested, the population
increased substantially through the 1960s and 1970s, and by 1980 was
probably approaching the carrying capacity of the habitat (Fay et al.
1989, p. 4).
Total harvest removals (combined commercial and subsistence
harvests in the United States and Russia), including estimates of
animals struck and lost, for the 1960s and 1970s averaged 5,331 and
5,747 walrus per year. Between the years of 1976 and 1979, the State of
Alaska managed the walrus population under a federally imposed
subsistence harvest quota of 3,000 walrus per year. Relinquishment of
management authority by Alaska to the Service in 1979 lifted this
harvest quota (the MMPA conditionally exempts Alaska Natives from the
take prohibitions; i.e., subsistence harvest must not be conducted in a
wasteful manner), which may have also contributed to the increased
harvest rates in subsequent years (USFWS 1994, p. 2). Specifically, the
1980s saw an increase in harvest, with a total removal estimate
averaging 10,970 walrus per year (Service, unpublished data). The
increased harvest rates in this decade may reflect several factors,
including the absence of a harvest quota (USFWS 1994, p. 2), commercial
harvest in Russia, and increased availability of walruses to
subsistence hunters coinciding with the population reaching carrying
capacity (Fay and Kelly 1989, p. 1; Fay et al. 1997, p. 558). The
increase in harvest in the 1980s was accompanied by an increase in the
proportion of females harvested, and may have caused a population
decline (Fay et al. 1997, p. 549). Harvest levels in the 1990s were
about half those of the previous decade, averaging 5,787 walrus per
year. The 2000-2008 average annual removal, which was 5,285 walrus per
year, was about 9 percent lower than the removal in the 1990s (Service,
unpublished data). In the United States for the years 2004-2008, the
communities of Gambell and Savoonga on St. Lawrence Island, Alaska,
have accounted for 84 percent of the reported U.S. harvest and 43
percent of the harvest rangewide (Garlich-Miller, et al. 2011, Section
220.127.116.11 ``Regional Harvest Patterns''). The St. Lawrence Island average
reported harvest, not corrected for animals that are struck and lost or
hunter noncompliance with the Marking Tagging and Reporting Program,
(the struck and lost correction and the MTRP are discussed below) for
2004-2008 is 988 animals (Service, unpublished data).
The lack of information on population status or trends makes it
difficult to quantify sustainable removal levels for the Pacific walrus
population (Garlich-Miller et al. 2011, Section 18.104.22.168 ``Harvests
Sustainability''). Recent (2003-2007) annual harvest removals in the
United States and Russia have ranged from 4,960 to 5,457 walrus per
year, representing approximately 4 percent of the minimum population
estimate of 129,000 animals (FWS 2010, p. 2). These levels are lower
than those experienced in the early 1980s (8,000-10,000 per year) that
led to a population decline (Fay et al. 1989 pp. 3-4). Chivers et al.
(1999, p. 239) modeled walrus population dynamics and estimated the
maximum net productivity rate (Rmax) for the Pacific walrus population
at 8 percent per year. Wade (1998, p. 21) notes that one half of Rmax
(4 percent for Pacific walruses) is a reasonably conservative (i.e.,
sustainable) potential biological removal (PBR) level for marine mammal
populations below carrying capacity, because it provides a reserve for
population growth or recovery. The PBR level, as defined under the
MMPA, is the maximum number of animals, not including natural
mortalities, that may be removed from a marine mammal stock while
allowing that stock to reach or maintain its optimum sustainable
population. Changes in productivity rates or population size could
eventually result in unsustainable harvest levels if harvest rates do
not adjust in concert with changes in population status or trend.
There are no Statewide harvest quotas in Alaska; however, some
local harvest management programs have been developed. Round Island,
within the Walrus Island State Game Sanctuary, was a traditional
hunting area of several Bristol Bay communities prior to the
development of the game sanctuary. Access to Round Island is controlled
by the State of Alaska via a permit system. To continue the traditional
hunt, the local communities proposed a cooperative agreement, which
resulted in a quota of 20 walrus and a 40-day hunting season in the
fall (Chythlook and Fall 1998, p. 5). The management agreement was
negotiated by the Service, Bristol Bay Native Association/Qayassiq
Walrus Commission, the Eskimo Walrus Commission, and Alaska Department
of Fish and Game (ADFG), and sanctioned in a signed memorandum of
understanding. The State of Alaska issues hunting access permits only
during the open season. If the quota is reached, additional hunting
access could be denied and existing permits could be revoked. Recent
harvests at Round Island have ranged from zero to two walruses per
year. No walrus were harvested on Round Island in 2009 or 2010. Bristol
Bay hunters also hunt elsewhere in the area without restriction, and
may be shifting hunting efforts to islands outside the State game
sanctuary as the monetary cost of traveling to Round Island is often
With an interest in reviving traditional law, advancing the idea of
self-regulation of the subsistence harvest, and initiating a local
management infrastructure due to concern about changing sea-ice
dynamics and the walrus population, the Native Villages of Gambell and
Savoonga on St. Lawrence Island have recently formed Marine Mammal
Advisory Committees (MMAC), and implemented local ordinances
establishing a limit of four walruses per hunting trip. Walruses that
are struck and lost (wounded and not retrieved), as well as calves, do
not count against this limit. In addition, there is no limit on the
number of trips, so the effectiveness of this ordinance in limiting
total harvest is dependent on the total number of hunting trips.
Factors such as subsistence needs, social mores, distance of walrus
from the village, weather, success of previous trips, needs of
immediate and extended family members, and monetary cost of making a
trip all play a part in the number of trips a hunting party makes. The
spring hunting season of 2010 was
the first to have the trip-limit ordinances in place. We estimate that
91 percent of the hunting trips were in compliance with the ordinance
by taking no more than four adult/subadult walrus per trip (Service,
Subsistence harvest reporting in the United States is required
under section 109(i) of the MMPA, and is administered through a
Marking, Tagging, and Reporting Program (MTRP) codified at 50 CFR
18.23(f). The MTRP requires Alaska Native hunters to report the harvest
of walrus and present the ivory for tagging within 30 days of harvest.
The Service also administers the Walrus Harvest Monitor Project (WHMP),
which is an observer-based data-collection program conducted in the
communities of Gambell and Savoonga during the spring harvest. This
program is designed to collect harvest data and biological samples. Not
all harvest in the United States is reported through the MTRP
(regulatory program). The Service uses the WHMP (observer-based)
harvest data to supplement MTRP data to develop a correction factor for
noncompliance to estimate the number of walrus harvested, but not
reported through the MTRP. The MTRP-reported harvest data (Statewide)
is corrected for noncompliance (unreported harvest), and that total is
then corrected to account for animals struck and lost (estimated at 42
percent of the walrus that are shot). Current accuracy of the struck
and lost estimate is unknown and should be re-estimated (USFWS 2010, p.
4). Compliance rates with the MTRP vary considerably from year to year,
with estimates ranging from a low of 60 percent to a high of 100
Subsistence harvest in Chukotka, Russia, is controlled through a
quota system. An annual subsistence quota is issued through a decree by
the Russian Federal Fisheries Agency. Quota recommendations are based
on sustainable removal levels (approximately 4 percent of the
population based on population and productivity estimates) (Garlich-
Miller and Pungowiyi 1999 p. 32). Because the population is shared with
the United States, Russian quota recommendations have generally been 2
percent or less of the estimated total population (Garlich-Miller and
Pungowiyi 1999, p. 32; Kochnev 2010, pers. comm.). Russian harvest
quotas are set annually and recent quota reductions in Russia of
approximately 57 percent from 2003-2010 have been in response to a
presumed population decline based in part on observed haulout
mortalities from trampling and results from various population surveys.
According to Kochnev (2004, p. 286), all the Pacific walrus haulouts of
the Arctic coast of Chukotka, Russia, are characterized by a high
disturbance level. The majority of these haulouts in Chukotka are near
coastal villages, and used by local subsistence hunters (Kochnev 2004,
The harvest reporting program in Russia is administered by the
Russian Agricultural Department. The harvest in Russia has been
traditionally conducted by hunting teams from each village. Team
leaders are required to submit two harvest reports per month. However,
walrus hunting by individual hunters (those not part of a harvest team)
has increased since the inception of the Russian Federation, and there
is no official mechanism for individuals to report their harvest; as a
result, Russian harvest estimates are biased low to an unknown degree
(Kochnev 2010, pers. comm.). In addition, the Russians do not adjust
their harvest estimates for animals that are struck and lost. The
Service assumes that the Russian struck and lost rate is comparable to
the U.S. rate, and applies the struck and lost correction factor of 42
percent to the Russian harvest data when estimating total subsistence
harvest levels. This correction provides a more accurate estimate of
the number of animals removed from the population due to harvest.
Subsistence removals of walrus in the United States are closely
tied to social and traditional customs, subsistence needs, sea-ice
dynamics, weather, and monetary costs related to hunting. We predict
that the range-wide walrus population will be smaller in the future,
due to changes in summer sea-ice cover and associated impacts; thus,
fewer walrus overall will be available for harvest. However, in the
Bering Strait region, winter and spring sea ice is expected to persist
through mid-century; walrus will likely continue to be locally abundant
in numbers that would enable harvest to continue at levels similar to
current ones, over time. Because these animals would be available to
local subsistence hunters around St. Lawrence Island and other Bering
Strait villages, the Pacific walrus would remain an important
subsistence resource. Subsistence harvest of walrus is extremely
important to several Alaska Native cultures. The primary factor
influencing the number of walrus harvested each year will be the
general availability of walruses in the Bering Strait region.
Given current and projected sea-ice conditions, and without
additional Tribal, State or Federal hunting regulations to limit or
restructure the harvest, we do not expect harvest pressure in the
Bering Strait region to change appreciably in the foreseeable future
(Garlich-Miller et al. 2011, Section 22.214.171.124.1 ``Climate Change''). The
St. Lawrence Island Tribal Governments and subsistence hunters have
recently taken steps to modify their harvest patterns through the
formation of Marine Mammal Advisory Committees, and the adoption of
local ordinances limiting the number of walrus harvested per hunting
trip by Tribal members. These are substantial efforts on the part of
the Tribes and subsistence hunters, and the Service looks forward to
continuing to work through the co-management structure (which allows
for cooperative efforts between the Service, Alaska Natives, and State
agencies; MMPA sec. 119(b)(4)) to ensure that the harvest of the
Pacific walrus remains sustainable for future generations. However, the
current measures to regulate the subsistence harvest do not limit the
harvest of females or provide limits on the total number of walruses
harvested and, therefore, are not wholly sufficient to ensure that
harvest in the Bering Strait region will be sustainable long term. The
tribal ordinances are structured in such a way that the Marine Mammal
Advisory Committees could enact additional regulations in the future to
address efficiency (reduce the number of animals that are struck and
lost), restructure the sex ratio of the harvest, or impose quotas upon
their Tribal members, or enact other measures to manage the harvest.
In the Bristol Bay and the Yukon-Kuskokwim regions of Alaska,
levels of subsistence harvest of walrus may decline slightly, in light
of declines in southern Bering Sea ice in the winter (subsistence
hunters search for walrus that are resting on ice floes) and a recent
trend of fewer male walrus remaining in Bristol Bay during the summer.
However, harvest in these regions is already so low--averaging 5 and 18
walrus reported as harvested per year, respectively, for 2004 through
2008 (Service, unpublished data)--that it likely does not have an
appreciable effect on the population. Future harvest patterns and
levels are not anticipated to change significantly in either region
(Garlich-Miller et al. 2011, Section 126.96.36.199.1 ``Climate Change'').
In the North Slope region of Alaska, reported subsistence harvest
averaged 48 walrus per year from 2004-2008. As summer sea ice in the
Chukchi Sea recedes out over deep arctic basin waters, it is
anticipated that coastal haulouts will form along the Chukchi coast
into the foreseeable future. Large
concentrations of walrus on shore for longer periods of time could
afford opportunity for additional harvest. The potential for hunting
activity to create a stampede resulting in injuries or mortalities, or
to displace animals from preferred forage areas (Kochnev 2004, p. 285)
is of greater concern than the direct mortalities associated with
harvest. Although the potential for increased harvest exists, we do not
expect the harvest to increase based on the fact that these
communities' subsistence focus is on bowhead and beluga whales, due to
a strong cultural connection and tradition as a whaling culture. North
Slope coastal communities also have access to a wider array of
resources than island communities and rely much more heavily on other
marine mammals, seabirds, fish and terrestrial mammals to meet their
subsistence needs (MMS 2007, p. IV-186). Due to the presence of the oil
industry, North Slope communities also have a stronger economic base
than the Bering Strait communities, and therefore do not rely as
heavily on ivory carving as a source of cash in the local economy.
As stated above, barring additional Tribal or Federal regulations
governing harvest, we predict that subsistence harvest is likely to
continue at or near current levels, even as the walrus population
declines in response to loss of summer sea ice. This is because walrus
are expected to continue to remain locally abundant and available for
subsistence harvest in the Bering Strait region in the winter and
spring. Over time, depending on how quickly the population declines,
future harvest levels will need to be reduced as population size
declines, or subsistence harvest will become unsustainable. Therefore,
we have determined that if subsistence harvest continues at current
levels, as expected, it represents a threat to the walrus population in
the foreseeable future. Although it is difficult to quantify
sustainable removal levels because of the lack of information on
Pacific walrus population status and trends, we have determined that
the current harvest of approximately 4 percent is at a sustainable
level based on a minimum population estimate of 129,000. Therefore, we
do not consider the current level of subsistence harvest to be a threat
to Pacific walrus at the present time. Our identification of
subsistence harvest as a threat to the species in the foreseeable
future is tied to expected population declines related to threats
associated with reduced summer sea ice, and is based on the best
scientific and commercial data available, including scientific
projections to the end of the 21st century.
Although we have suggested that overall harvest must adjust with
population size, there are strategies other than a numerical quota that
could be utilized in an effort to assure sustainability over the long
term. The co-management structure and the St. Lawrence Island Tribal
ordinances provide an effective means to address improvements in
hunting efficiency, and modification of the sex structure of the
harvest. Improving hunting efficiency by reducing the number of animals
which are struck and lost could potentially reduce the total number of
walrus removed from the population due to subsistence harvest. Adult
breeding-age females are the most important cohort of the population.
An overall reduction in the number of females removed annually while
still allowing an unlimited number of males to be harvested has had a
positive effect on a declining population in the past and could be an
effective means of managing harvests for sustainability into the
Our conclusion that subsistence harvest is a threat in the
foreseeable future is supported by the BN models prepared by the
Service and USGS. The sensitivity analyses of both models identified
subsistence harvest as one of the major drivers of model predictions.
The two models involved different assumptions relative to subsistence
harvest levels. In the Service model, we assumed, for the reasons
described above, that subsistence harvest levels would remain
relatively constant over time, even as the walrus population declined
in response to reduced sea-ice conditions. In the USGS model, Jay et
al. (2010b, p. 15) assumed that future harvest rates would be
proportional to walrus population size. However, these authors
acknowledge that if in the future, the walrus population declines, but
harvest continues at the current level, the population-level stress
caused by the harvest would effectively increase (Jay et al. 2010b, p.
16), thereby amplifying the impact of subsistence harvest on the
population. In the Service model, maintaining the harvest at
replacement levels (sustainable) reduced the probabilities of negative
effects by about 19 percent compared to a higher harvest (Garlich-
Miller et al. 2011, Table 8). Results from the USGS model suggest that
although minimizing harvest from current levels may have little
positive effect on population outcomes in the future, harvests of high
(greater than 4 percent of the population) and very high levels
(greater than 6 percent) could add significantly to the adverse effects
of future sea-ice conditions on population outcomes through the end of
the century (Jay et al. 2010b, p. 16).
Summary of Factor B
As discussed above, scientific and educational utilization of
walruses is currently at low levels, regulated both domestically and in
the Russian Federation, and is not a threat to the Pacific walrus now
or in the foreseeable future. Recreational (sport) hunting of Pacific
walrus is prohibited under the MMPA and by Russian legislation;
therefore, it is not a threat to the Pacific walrus now or in the
foreseeable future. United States import/export is not a threat to the
Pacific walrus now or in the foreseeable future because Pacific walrus
specimens exported from or imported into the United States consist
mostly of fossilized bone and ivory shards, and any other walrus ivory
can only be imported into or exported from the United States after it
has been legally harvested and substantially altered to qualify as a
Native handicraft. Commercial hunting of Pacific walrus in the United
States is prohibited under the MMPA. Commercial hunting in Russia has
not occurred since 1991 and could not resume unless a harvest quota
based on sustainability were established; therefore, it is unlikely
that Russian commercial harvest will be a threat to the Pacific walrus
Over the past 50 years, Pacific walrus population annual harvest
removals have varied from 3,200 to 16,000 per year. Over the past
decade, subsistence harvest removals in the United States and Russia
have averaged approximately 5,000 per year. Recent harvest levels are
significantly lower than historical highs, although the lack of
information on population status and trend make it difficult to
quantify sustainable removal levels. Anticipated reductions in
population size in response to losses in sea-ice habitats and
associated impacts underscore the need for reliable population
information as a basis for evaluating the sustainability of future
harvest levels. Research leading to a better understanding of
population responses to changing ice conditions and modeling efforts to
examine the impact of various removal levels are currently under way by
USGS and others.
Subsistence harvest levels in Russia are presently controlled under
a quota system based upon the 2006 population estimate. The Russian
quota has been reduced recently in response to the loss of several
thousand calves at terrestrial haulouts as a result of trampling events
in recent years and their belief that the
population is in decline. Although the subsistence walrus harvest in
Alaska is not regulated under a quota system, the MMPA provides for the
development of voluntary co-management agreements with Alaska Native
organizations. Notably, hunting ordinances were implemented in 2010 in
Alaska's two primary hunting communities, providing a promising
mechanism for self regulation of harvests. While it is premature to
evaluate the efficacy of such local ordinances over the long term, the
recent establishment of these local management programs offers a
tangible framework for additional harvest management, as necessary. The
existing harvest reporting and monitoring programs provide information
on harvest program effectiveness and also provide data on harvest
trends and composition. In conjunction with information on population
status and trends, this information will be used to evaluate future
harvest management strategies. Additionally, a multi-party agreement
between the Service, State of Alaska, and two Alaska native groups
includes a defined hunting season and a quota for the Round Island
State Game Sanctuary.
We wish to underscore the importance of the efforts the Alaska
Native community has undertaken to manage subsistence harvest, and we
are hopeful that community-based harvest regulations to improve
efficiency (reduce animals that are struck and lost), adjust the sex
structure of the harvest (reduce the overall take of females), or limit
the total number of walrus taken will be developed in the future. The
Service prefers to develop community-based harvest regulations. To that
end, we will continue working directly with the subsistence hunting
community and the Eskimo Walrus Commission to continually refine
harvest monitoring and reporting and to share information on population
status and trend from both traditional ecological knowledge and western
science. We recognize that to improve our ability to manage the walrus
harvest, the refinement of methods to estimate walrus abundance and
trend, productivity, and habitat carrying capacity is needed. Our
longstanding co-management agreement between the Service and the Eskimo
Walrus Commission provides an important forum for continued dialogue
about these harvest-related issues and a mechanism for developing
further harvest management options.
In summary, although the Service supports efforts by subsistence
communities to implement voluntary programs with the goal of
sustainable Pacific walrus harvests, we acknowledge that there are
currently no regulatory mechanisms in place to assure the
sustainability of subsistence harvests. In the absence of such
regulatory mechanisms, we do not expect harvest levels in the Bering
Strait region to change appreciably in the foreseeable future.
Subsistence harvest is predicted to continue at similar levels,
independent of future walrus population trends. Barring additional
Tribal or Federal harvest management actions, we anticipate that the
proportion of animals harvested will increase relative to the overall
population, and this continued level of subsistence harvest will become
unsustainable. Therefore, although we do not identify current
subsistence harvest as a threat to the walrus population at the present
time, we have determined that this continued level of subsistence
harvest will become a threat to the walrus population, as it declines
in the foreseeable future. Based on the best scientific and commercial
data available, we find that overutilization in the form of subsistence
harvest at current levels, is likely to threaten the Pacific walrus in
the foreseeable future.
Factor C. Disease or Predation
Future disease and predation dynamics may be tied to environmental
changes associated with changes in sea ice and other environmental
parameters that influence disease vectors and exposure, and predation
opportunities. Our ability to reliably predict the potential level and
influence of disease and predation is tied to our ability to predict
environmental change and is related to our understanding of sea-ice
dynamics. Under Factor A, we also discussed the potential increase in
predation by polar bears associated with increasing dependence of
Pacific walrus on coastal haulouts caused by the loss of sea-ice
Infectious viruses and bacteria have the capacity to impact marine
mammals, particularly when first introduced to a population (Duignan et
al. 1994, p. 90; Osterhaus et al. 1997, p. 838; Ham-Lamme et al. 1999,
p. 607; Calle et al. 2002, p. 98; Burek et al. 2008, p. 129). Pacific
walrus have had exposure to several pathogens, such as Caliciviruses
(Fay et al. 1984, p. 140; Smith et al. 1983, p. 86; Barlough et al.
1986, p. 166), Leptospirosis (Calle et al. 2002, p. 96), and Influenza
A virus (Calle et al. 2002, p. 95-96), none of which have resulted in
large die-offs of animals.
Additionally, the introduction of new viruses to populations of
marine mammals may be the result of changing distribution patterns of
the host (Duignan et al. 1994, p. 90; Dobson and Carper 1993; p. 1096).
For example, phocine distemper virus (PDV) was recently found in the
North Pacific (Goldstein et al., 2009 p. 2009), and while antibodies to
PDV have been found in Atlantic walrus (Duignan et al. 1994, p. 90;
Nielson et al. 2000, p. 510), as yet there has been no evidence of
exposure in Pacific walruses.
Parasites are common among pinnipeds, and their infestations result
in various effects to individuals and populations, ranging from mild to
severe (Fay 1982, p. 228; Dubey 2003, p. 275). For example, the
ectoparasite Antarctophthirus trichchi is an anopluran (sucking) louse
that lives in the skin folds of walruses (Fay 1982, p. 228), causing
external itching, but no serious health issues (Fay 1982, p. 228).
Endoparasites, protozoa, and helminthes (microorganisms and
parasitic worms) also may impact populations, as they rely on locating
suitable hosts to complete all or part of their life cycle. Of the 17
species of helminthes known to parasitize Pacific walrus, 2 species are
endemic (Fay 1982, p. 228; Rausch 2005, p. 134): The cestode
Diphyllobothrium fayi, found only in the small intestine, and the
nematode Anisakis rosmari, found only in stomachs (Heptner and Naumov
1976, p. 52).
Trichinella spiralis nativa (Rausch et al. 2007, p. 1249) infects
Pacific walruses at a rate of about 1.5 percent (Bukina and Kolevatova
2007, p. 14). While the possibility of contracting Trichinosis from
infected walrus has been an issue of concern to some subsistence
hunters for decades, Trichinella does not appear to cause any ill
effects in walrus (Rausch et al. 2007, p. 1249).
The intracellular parasite Toxoplasma gondii is a significant cause
of encephalitis in sea otters and harbor seals (Dubey et al. 2003, p.
276), and heart, liver, intestine and lung lesions in sea lions (Dubey
et al. 2003, p. 281). It has been isolated from at least 10 species of
marine mammals, including walrus (Dubey et al. 2003, p. 278). Of the 53
Pacific walruses tested between 1976 and 1998, about 5.6 percent were
positive for T. gondii (Dubey et al. 2003, p. 278). T. gondii has also
been documented in some walrus prey (e.g., seals and bivalves; Fay
1982, p. 146; Lowry and Fay 1984, p. 12; Dubey et al. 2003, p. 278;
Lindsay et al. 2004, p. 1055; Jensen et al. 2009, p. 1); however, it
will not likely play a significant role in the health of the Pacific
walrus population, because they have a history
of exposure and no large walrus mortality events have been attributed
to this organism.
Neospora caninum is a protozoan parasite that was found in 3 of 53
walruses (Dubey et al. 2003, p. 281). The health implication for N.
caninum exposure in walruses is unknown, but the potential for exposure
In summary, the occurrence and effects of diseases and parasites on
Pacific walrus appear to be minor in terms of potential population-
level effects. Several diseases and parasites appear at chronically low
levels; however, no outbreaks resulting in large die-offs have been
observed. A changing climate may increase exposure of walrus to new
organisms. Additionally, increased use of terrestrial haulouts may
escalate the risk of transmission of disease (Fay 1974, p. 394). This
potential stressor is part of the USGS Bayesian network model, which
linked lower-shelf ice availability to walrus crowding and incidence of
disease and parasites in the population, by increasing the walrus
haulout sizes and concentrating their locations (Jay et al. 2010b, p.
9). However, sensitivity analysis did not identify disease and
predation as having a significant effect on model outcomes (Jay et al.
2010b, p. 86). In addition, increased exposure to disease or parasites
has yet to be documented, and there are no clear transmission vectors
that would change the level of exposure. At this time, disease and
parasites are not considered to be threats to the Pacific walrus
population, and no evidence exists that they will be in the foreseeable
Because of their large size and formidable tusks, adult walruses
have few natural predators. Polar bears (Ursus maritimus) and killer
whales (Orcinus orca) tend to prey on walruses only opportunistically
and focus primarily on younger animals.
However, when suitable sea-ice platforms are not available, Pacific
walruses haul out onto land, where they become vulnerable to
terrestrial predators and associated stampede events. Walrus carcasses
accumulating at coastal haulouts provide scavenging opportunities that
may attract bears (Ovsyanikov 2003, p. 13). Brown bears, wolverines,
and feral dogs have also been observed scavenging at coastal haulouts
in Chukotka, Russia, in recent years (Kochnev 2010, pers. comm.) and
contribute to disturbances at these haulout sites. Programs have been
established in recent years at some coastal haulouts in Chukotka,
Russia, to mitigate disturbance-related mortalities that include
collection of walrus carcasses and establishment of polar bear feeding
areas away from the haulouts and villages (Kavry 2010, pers. comm.).
The increase in walrus carcasses at coastal haulouts in Chukotka in
recent years is likely playing an important role in shifting habitat-
use patterns of some polar bears and their progeny (Kochnev 2006, p.
1). Walrus carcasses now represent an important food resource for polar
bears on Wrangel Island in autumn and early winter (Kochnev 2002, p.
137). Polar bears begin to appear near walrus haulouts on Wrangel
Island in early August, about a month prior to the arrival of walruses
(Kochnev 2002, p. 137). In the 1990s, the number of polar bears coming
ashore on Wrangel Island peaked in late October, averaging 50 bears
(Kochnev 2002, p. 137). However, in 2007, approximately 500-600 polar
bears were stranded on Wrangel Island (Ovsyanikov and Menyushina 2007,
p. 1), along with herds of walruses (up to 15,000 in one group); some
of the walruses were in poor condition and polar bears were able to
kill them relatively easily. At least 11 cases of polar bear predation
on motherless calves were also observed (Ovsyanikov et al. 2007, p. 1).
Because the summer/fall open-water period is projected to increase
in the foreseeable future, polar bears are also predicted to spend more
time on land. As a result, we anticipate that there will be greater
interaction between the two species, and terrestrial walrus haulouts
may become important feeding areas for polar bears. The presence of
polar bears along the coast during the ice-free season will likely
influence patterns of haulout use by walrus, and may play a significant
role in the selection of coastal haulout sites (Garlich-Miller et al.
2011, Section 188.8.131.52 ``Polar Bears''). We anticipate walrus to respond
to this expected increase in interaction with polar bears by shifting
to other coastal haulout locations. However, if walrus are forced to
move to other locations to avoid predation by polar bears, the walrus
may be displaced from preferred haulout locations with adequate prey
resources to other areas that may or may not have less-suitable
foraging habitat. It is also possible that walrus will be forced to
move to different haulout locations more frequently, with increased
energetic costs to them. Kochnev (2004, p. 286) asserted that when
Pacific walrus migrate in autumn, from haulout to haulout on the Arctic
coast of Chukotka, Russia, the increased pressure from humans and
animal predators prevents walruses from getting adequate rest at the
coastal haulouts, and some of the animals die in stampedes caused by
disturbance events. The magnitude of these potential energetic costs
would be determined by the frequency and distance of the shifts in
location. Although predation by polar bears on Pacific walrus has been
observed, no population-level effects have been documented to date;
therefore, polar bear predation is not currently a threat to the
Pacific walrus. As sea ice declines and Pacific walrus spend more time
on coastal haulouts, however, it is likely that polar bear predation
will increase. However, we cannot reliably predict the level of such
predation. Although we have identified these issues as stressors for
Pacific walrus, we are not able to conclude with sufficient reliability
that they will rise to the level of a threat to the Pacific walrus
population in the foreseeable future.
Although sea-ice habitats also provide some protection against
killer whales, which have limited ability to penetrate far into the ice
pack, accounts of killer whale predation on walrus have been observed
by Russian scientists and Alaskan Natives (Fay 1982, pp. 216-220). Some
observers suggest that killer whales primarily prey upon the youngest
animals, and instances of killer whale predation on adult walruses have
also been documented (Fay and Stoker 1982, p. 2). The mortality from
killer whale predation is unknown, but an interpretation of an
examination of 52 walrus carcasses that washed ashore on St. Lawrence
Island in 1951 (Fay 1982, p. 220) suggested that 17 walrus (33 percent)
died from injuries consistent with killer whale predation. Fay and
Kelly reported that 2 of 15 (13 percent) animals they examined had
likely been killed by killer whales (Fay and Kelly 1980, p. 235). The
potential for killer whales to expand their range and begin to target
walruses at northern haulouts exists; however, this remains speculative
at this time. Reduced availability of sea ice may lead to walruses
spending more time in the water where they may be more susceptible to
predation by killer whales (Boveng et al. 2009, p. 169). However, there
is no evidence that killer whale predation has ever limited the Pacific
walrus population, and there is no evidence of increased presence of
killer whales in the Bering or Chukchi seas; therefore, killer whale
predation is not a threat to the Pacific walrus now and is unlikely to
be a threat in the foreseeable future.
Sensitivity analyses of both BN models found that disease and
predation had very little effect on model outcomes. For the Service
model, disease and predation altered model
outcomes by 1.2 and 2.2 percent, respectively (Garlich-Miller et al.
2011, Table 8). For the USGS model, disease and predation accounted for
less than 1 percent of entropy (variation) reduction (Jay et al. 2010b,
Summary of Factor C
Disease and predation are not considered to represent threats to
the Pacific walrus population at this time. Although a changing climate
may increase exposure of walrus to new pathogens, there are no clear
transmission vectors that would change levels of exposure, and no
evidence exists that disease will become a threat in the foreseeable
future. As walruses and polar bears become increasingly dependent on
coastal haulouts, we expect interactions between the two species to
increase. The presence of polar bears stranded along the coast during
the ice-free season will likely influence patterns of haulout use and
may play a significant role in the selection of coastal haulout sites.
There is no evidence that killer whale predation has ever limited the
Pacific walrus population, and there is no evidence of increased
presence of killer whales in the Bering or Chukchi seas. The net effect
of future predation levels on the population cannot be reliably
predicted, because of uncertainties relative to distribution of walrus
and their potential predators and the amount of potential overlap, and
the degree to which these predators would target Pacific walrus. The
best available scientific information indicates that the effect of
predation on Pacific walrus may be a source of concern in the
foreseeable future, particularly at the localized scale, where walrus
congregate at coastal haulouts. However, we do not anticipate predation
to be a threat to the entire population. Therefore, we conclude, based
on the best scientific and commercial data available, that disease and
predation are not threats to the Pacific walrus now, nor are they
likely to become threats to the population in the foreseeable future.
Factor D. The Inadequacy of Existing Regulatory Mechanisms
In determining whether the inadequacy of regulatory mechanisms
constitutes a threat to the Pacific walrus, we focused our analysis on
the specific laws and regulations aimed at addressing the two primary
threats to the walrus-the loss of sea-ice habitat under Factor A and
subsistence harvest under Factor B. These specific regulatory
mechanisms are described below. Although none of the other stressors on
walrus rise to the level of a threat, we also provide an overview of
additional laws and regulations containing protective measures for the
Regulatory Mechanisms To Address Sea-Ice Loss
As explained under Factor A, a primary threat to the survival of
the Pacific walrus is the projected loss of sea-ice habitat due to a
warming climate and its consequences for walrus populations. Currently,
there are no regulatory mechanisms in place that effectively address
GHG emissions, climate change, and associated sea-ice loss.
National and international regulatory mechanisms to comprehensively
address the causes of climate change are continuing to be developed.
International efforts to address climate change began with the United
Nations Framework Convention on Climate Change (UNFCCC), which was
signed in May 1992. The UNFCCC states as its objective the
stabilization of GHG concentrations in the atmosphere at a level that
would prevent dangerous anthropogenic interference with the climate
system, but it does not impose any mandatory and enforceable
restrictions on GHG emissions. The Kyoto Protocol, negotiated in 1997,
became the first agreement added to the UNFCCC to set GHG emissions
targets for signatory counties, but the targets are not mandated. The
Climate Change Act of 2008 established a long-term target to cut
emissions in the United Kingdom (UK) by 80 percent by 2050 and by 34
percent in 2020 compared to 1990 levels, but the law does not pertain
to any emissions outside the UK. Other international laws, regulations,
or other legally binding requirements imposing limits on GHG emissions
to further the goals set forth in the UNFCCC and the Kyoto Protocol
have not yet been adopted.
In the United States, efforts to address climate change focus on
the Clean Air Act and a number of voluntary actions and programs.
Specifically, the Clean Air Act of 1970 (42 U.S.C. 7401 et seq.), as
amended, requires the Environmental Protection Agency (EPA) to develop
and enforce regulations to protect the general public from exposure to
airborne contaminants hazardous to human health. In 2007, the Supreme
Court ruled that gases that cause global warming are ``pollutants''
under the Clean Air Act, and that the EPA has the authority to regulate
carbon dioxide and other heat-trapping gases (Massachusetts et al. v.
EPA 2007 (Case No. 05-1120)). On December 29, 2009, the EPA adopted a
regulation to require reporting of greenhouse gas emissions from fossil
fuel suppliers and industrial gas suppliers, direct greenhouse gas
emitters, and manufacturers of heavy duty and off-road vehicles and
engines (EPA 2009, p. 56260). The rule does not actually regulate
greenhouse gas emissions, however; but it merely requires that
emissions above certain thresholds be monitored and reported (EPA 2009,
p. 56260). On December 7, 2009, the EPA found that the current and
projected concentrations of six greenhouse gases in the atmosphere
threaten public health and welfare under section 202(a) of the Clean
Air Act. This finding by itself does not impose any requirements on any
industry or other entities to limit greenhouse gas emissions. While the
finding could be considered a prerequisite for any future regulations
developed by the EPA to reduce GHG emissions, no such regulations exist
at this time. In addition, it is unknown whether any regulations will
be adopted in the future as a result of the finding, or how effective
such regulations would be in addressing GHG emissions and climate
Summary of Regulatory Mechanisms To Address Sea-Ice Loss
Based on our analysis (above), we conclude that there are no known
regulatory mechanisms in place at the national or international level
that are likely to effectively reduce or limit GHG emissions. This
conclusion is corroborated by the projections we used to assess risks
to sea ice from GHG emissions, as described earlier in this finding.
Therefore, the lack of mechanisms to regulate GHG emissions is already
included in our risk assessment in Factor A, which shows that, without
additional regulation, GHG emissions and corresponding sea-ice losses
are likely to increase in the foreseeable future. Thus, we conclude
that regulatory mechanisms do not currently exist to effectively
address the loss of sea-ice habitat.
Regulatory Mechanisms To Ensure Harvest Sustainability
While current harvest levels are considered sustainable,
subsistence harvest has been identified as a threat to the Pacific
walrus within the foreseeable future. As explained in Factor B,
subsistence harvest is expected to continue at current levels, while
the walrus population is projected to decline with the continued loss
of sea ice and associated impacts. Barring additional Tribal or Federal
regulations, we anticipate that the proportion of animals harvested
will increase relative
to the overall population. As a result, the current level of
subsistence harvest will likely become unsustainable in the foreseeable
future. To address this threat, regulatory mechanisms will need to be
developed and implemented to ensure that future harvest levels are
reduced in proportion to the declining walrus population such that
subsistence harvest levels are sustainable. To determine whether such
regulatory mechanisms currently exist, we evaluated the various
international and domestic laws and regulations, cooperative
agreements, and local ordinances relevant to the subsistence harvest of
In Russia, the Pacific walrus is a protected species managed
primarily by the Fisheries Department within the Ministry of
Agriculture. The subsistence harvest of walrus in Russia is authorized,
but it is controlled through a quota system. Under the Russian ``Law on
Fishery and Protection of Aquatic Biological Resources,'' the harvest
of walrus is based upon the total annual catch (TAC) of walrus (Food
and Agriculture Organization of the United Nations 2007, p. 4). The TAC
takes into account the total population and productivity, based in part
on the recommendations of scientists from the Pacific Research
Fisheries Center (Chukotka Branch-ChukotTINRO) regarding a sustainable
removal level (Kochnev, 2010 pers. comm.). The 2010 quota has been set
at 1,300 animals (Kochnev, 2010 pers. comm.).
In the United States, section 101(b) of the MMPA (16 U.S.C.
1371(b)) provides an exemption for the continued nonwasteful harvest of
walrus by coastal Alaska Natives for subsistence and handicraft
purposes. Pursuant to Section 101(b)(3), regulations limiting the
subsistence harvest of walrus may be adopted, but only if a
determination is first made that the species or stock has been
depleted, following notice and determination by substantial evidence on
the record following an agency hearing before an administrative law
judge. To date, no determination has ever been made that the species or
stock has been depleted, and thus, no regulations establishing limits
on the subsistence harvest of Pacific walrus in the United States have
Subsistence harvest reporting in the United States is required
under section 109(i) of the MMPA. This requirement is administered
through the Marking, Tagging, and Reporting Program (MTRP) and requires
Alaska Native hunters to report the harvest of all walrus and present
the ivory for tagging within 30 days of harvest. Since its
implementation in 1988, the Service has used the program to improve its
understanding of subsistence harvest by recruiting, training, and
outfitting village residents to collect harvest data and tag tusks.
Pursuant to the program, the Service has also maintained a walrus
harvest reporting database and developed and implemented important
outreach and education programs.
In addition to the MTRP, the Service also administers the Walrus
Harvest Monitoring Program, which is an observer-based data collection
program conducted in the communities of Gambell and Savoonga during the
spring harvest. The program is designed to collect basic biological
information on harvested walrus, collect biological samples for
research, and supplement the MTRP data set, to allow the Service to
more accurately account for the unreported segment of the harvest. The
Service law enforcement office simultaneously conducts an enforcement
program designed to enforce the nonwasteful take provision of the MMPA.
Some local harvest management programs have been adopted in
addition to the above subsistence harvest data collection programs.
Through a 1997 cooperative agreement between the Service, Bristol Bay
Native Association/Qayassiq Walrus Commission, the Eskimo Walrus
Commission, and ADFG, the subsistence harvest of walrus at Round
Island, a traditional hunting area now located within the Walrus Island
State Game Sanctuary, is restricted to a 40-day fall hunting season and
a quota of 20 walrus (Chythlook and Fall 1998, pp. 4, 5). The harvest
level in this area has ranged from zero to two per year and represents
a very minor portion of the harvest in the United States.
Similarly, out of a desire to revive traditional law, to advance
the idea of self regulation of the subsistence harvest, and to initiate
a local management infrastructure, the Native villages of Gambell and
Savoonga on St. Lawrence Island have recently formed Marine Mammal
Advisory Committees (MMAC) and implemented local ordinances
establishing a limit of four walruses per hunting trip. The scope of
these ordinances is limited, however, as walruses that are struck and
lost and walrus calves do not count against this limit of four walruses
per trip, and the number of trips is not restricted. Additionally,
there is no quota on the total number of walruses that may be
Summary of Regulatory Mechanisms To Ensure Harvest Sustainability
After evaluating the laws, regulations, cooperative agreements, and
local ordinances described above, we conclude that adequate regulatory
mechanisms are not currently in place to address the threat that
continued levels of subsistence harvest pose to the Pacific walrus as
the population declines in the foreseeable future. The Russian harvest
is currently regulated with a quota system, based on the sustainability
of the harvest. In Alaska, no Statewide quota exists. An annual quota
does exist on Round Island, but the number of walrus harvested in this
area is miniscule in relation to the overall harvest. In the Bering
Strait Region, where the vast majority of U.S. harvest (84 percent) and
43 percent of the rangewide harvest occurs, local ordinances recently
adopted by two Native villages reflect the appreciation of the Native
community for the important role of self-regulation in managing the
subsistence harvest, and will serve as a starting point for future
cooperative efforts and the development of harvest management
strategies in the future. There are currently no tribal, Federal, or
State regulations in place to ensure the likelihood that, as the
population of walrus declines in response to changing sea-ice
conditions, the subsistence harvest of walrus will occur at a reduced
and sustainable level. As a result, we conclude that current regulatory
mechanisms are inadequate to prevent subsistence harvest from becoming
unsustainable in the foreseeable future. Therefore, we conclude that
current regulatory mechanisms do not remove or reduce the threat to the
Pacific walrus from future subsistence harvest.
Regulatory Mechanisms To Address Other Stressors
A number of regulatory mechanisms directed specifically at
protecting and conserving the walrus and its habitat are in place at
the international, national, and local level. These mechanisms may be
useful in minimizing the adverse effects to walrus from potential
stressors other than sea-ice loss and subsistence harvest, such as the
take of walrus for scientific or educational purposes, commercial
harvest, human disturbance, and oil spills. Because none of these other
stressors rise to the level of a threat to the Pacific walrus, we
acknowledge that the protections discussed here are not essential to
our determination of the adequacy of existing regulatory mechanisms to
address threats to the walrus.
The Convention on International Trade in Endangered Species of Wild
Fauna and Flora
The Convention on International Trade in Endangered Species of Wild
Fauna and Flora (CITES) is a treaty aimed at protecting species that
are or may be affected by international trade. The CITES regulates
international trade in animals and plants by listing species in one of
three appendices. The level of monitoring and regulation to which an
animal or plant species is subject depends on the appendix in which the
species is listed. At the request of Canada, the walrus was listed at
the species level in Appendix III, which includes species that are
subject to regulation in at least one country, and for which that
country has asked the other CITES Party countries for assistance in
controlling and monitoring international trade in that species. For
exportation of walrus specimens from Canada, an export permit may be
issued by the Canadian Management Authority if it finds that the
specimen was legally obtained. The import of walrus specimens into
countries that are parties to CITES requires the presentation of a
certificate or origin and, if the import was from Canada, an export
permit. All countries within the range of the walrus--that is, the
United States (Pacific walrus); the Russian Federation (Pacific and
Laptev Walrus), Canada, Norway, Greenland (Denmark), and Sweden
(Atlantic walrus) are members to the CITES and have provisions in place
to monitor international trade in walrus specimens.
Domestic Regulatory Mechanisms
Marine Mammal Protection Act of 1972
The Marine Mammal Protection Act of 1972, as amended (16 U.S.C.
1361 et seq.) (MMPA) was enacted to protect and conserve marine mammals
so that they continue to be significant functioning elements of the
ecosystem of which they are a part. The MMPA sets forth a national
policy to prevent marine mammal species or population stocks from
diminishing to the point where they are no longer a significant
functioning element of the ecosystems.
The MMPA places an emphasis on habitat and ecosystem protection.
The habitat and ecosystem goals set forth in the MMPA include: (1)
Management of marine mammals to ensure they do not cease to be a
significant element of the ecosystem of which they are a part; (2)
protection of essential habitats, including rookeries, mating grounds,
and areas of similar significance ``from the adverse effects of man's
action''; (3) recognition that marine mammals ``affect the balance of
marine ecosystems in a manner that is important to other animals and
animal products,'' and that marine mammals and their habitats should
therefore be protected and conserved; and (4) direction that the
primary objective of marine mammal management is to maintain ``the
health and stability of the marine ecosystem.'' Congressional intent to
protect marine mammal habitat is also reflected in the definitions
section of the MMPA. The terms ``conservation'' and ``management'' of
marine mammals are specifically defined to include habitat acquisition
The MMPA established a general moratorium on the taking and
importing of marine mammals, as well as a number of prohibitions that
are subject to a number of exceptions. Some of these exceptions include
take for scientific purposes, for purposes of public display, and for
subsistence use by Alaska Natives, as well as unintentional take
incidental to conducting otherwise lawful activities. The Service,
prior to issuing a permit authorizing the taking or importing of a
walrus, or a walrus part or product, for scientific or public display
purposes, reviews each request, provides an opportunity for public
comment, and consults with the U.S. Marine Mammal Commission (MMC), as
described at 50 CFR 18.31. The Service has determined that there is
sufficient rigor under the regulations at 50 CFR 18.30 and 18.31 to
ensure that any activities so authorized are consistent with the
conservation of this species and are not a threat to the species.
Take is defined in the MMPA to include the ``harassment'' of marine
mammals. ``Harassment'' includes any act of pursuit, torment, or
annoyance that ``has the potential to injure a marine mammal or marine
mammal stock in the wild'' (Level A harassment), or ``has the potential
to disturb a marine mammal or marine mammal stock in the wild by
causing disruption of behavioral patterns, including, but not limited
to, migration, breathing, nursing, breeding, feeding, or sheltering''
(Level B harassment) (16 U.S.C. 1362(18)(A)).
The MMPA contains provisions for evaluating and permitting
incidental take of marine mammals, provided the total take would have
no more than a negligible effect on the population or stock.
Specifically, under Section 101(a)(5) of the MMPA, citizens of the
United States who engage in a specified activity other than commercial
fishing (which is specifically and separately addressed under the MMPA)
within a specified geographical region may petition the Secretary of
the Interior to authorize the incidental, but not intentional, taking
of small numbers of marine mammals within that region for a period of
not more than 5 consecutive years (16 U.S.C. 1371(a)(5)(A)). The
Secretary ``shall allow'' the incidental taking if the Secretary finds
that ``the total of such taking during each five-year (or less) period
concerned will have no more than a negligible impact on such species or
stock and will not have an unmitigable adverse impact on the
availability of such species or stock for taking for subsistence uses''
(16 U.S.C. 1371(a)(5)(A)(i)). If the Secretary makes the required
findings, the Secretary also prescribes regulations that specify: (1)
Permissible methods of taking; (2) means of affecting the least
practicable adverse impact on the species, their habitat, and their
availability for subsistence uses; and (3) requirements for monitoring
and reporting. (16 U.S.C. 1371(a)(5)(A)(ii)). The regulatory process
does not authorize the activities themselves, but authorizes the
incidental take of the marine mammals in conjunction with otherwise
Regulations authorizing the nonlethal incidental take of walrus
from certain oil and gas activities in the Beaufort and Chukchi Seas
are currently in place. These regulations are based on a determination
that the effects of such activities, including noise, physical
obstructions, human encounters, and oil spills, are likely to be
sufficiently limited in time and scale that they would have no more
than a negligible impact on the stock (USFWS 2008, pp. 33212, 33226).
General operating conditions required to be imposed in specific
authorizations include: (1) Restrictions on industrial activities,
areas, and time of year; (2) restrictions on seismic surveys to
mitigate potential cumulative impacts on resting, feeding, and
migrating walrus; and (3) development of a site-specific plan of
operation and a site-specific monitoring plan to enumerate and document
any animals that may be disturbed. These and other safeguards and
coordination with industry called for under the MMPA have been useful
in helping to minimize industry effects on walrus.
A similar process exists for the promulgation of regulations
authorizing the incidental take of small numbers of marine mammals
where the take will be limited to harassment (16 U.S.C. 1371(a)(5)(D)).
These authorizations, referred to as Incidental Harassment
Authorizations, are limited to 1 year and require a finding by the
Department that the taking will have no more than a negligible impact
on the species or stock
and will not have immitigable adverse impact on the availability of
such species or stock for taking for subsistence uses. There are
currently no incidental harassment authorizations in place for the
As discussed under Factor E, shipping and anthropogenic noises are
expected to increase in the Chukchi and Beaufort Seas in the future,
and could impact the walrus or its habitat. Under the MMPA, however,
disturbance of walrus from such otherwise lawful human activity is
generally prohibited. While the MMPA does allow for the incidental
taking of walrus, any such authorizations for increasing shipping
activities or anthropogenic noise from industry would be required to be
based on a determination that impacts to the Pacific walrus would be
negligible and would not have an immitigable adverse impact on the
availability of Pacific walrus for the taking for subsistence uses,
consistent with the procedures outlined previously regarding the
promulgation of take regulations and incidental harassment
Similarly, the potential for commercial fishing to expand into the
Chukchi and Beaufort Seas could impact the Pacific walrus, as discussed
later in this finding. However, the MMPA has protections in place to
limit any potential incidental impacts of future commercial fisheries.
Specifically, section 118 of the MMPA (16 U.S.C. 1387) calls for
commercial fisheries to reduce any incidental mortality or serious
injury of marine mammals to insignificant levels approaching zero. In
its 2004 report to Congress regarding the commercial fisheries'
progress toward reducing mortality and serious injury of marine
mammals, the National Oceanic and Atmospheric Administration (NOAA)
concluded that: (1) Most fisheries have achieved levels of incidental
mortality consistent with the Zero Mortality Rate Goal; (2) substantial
progress has been made in reducing incidental mortality through Take
Reduction Plans; and (3) additional information will be needed for most
fisheries and stocks of marine mammals to accurately assess whether
mortality incidental to commercial fishing is at insignificant levels
approaching a zero mortality and serious injury rate (NOAA 2004,
Executive Summary). Thus, while commercial fishing could expand in the
future, such expansions would need to be consistent with existing
fisheries elsewhere in the United States that must limit their impacts
to marine mammals.
Outer Continental Shelf Lands Act
The Outer Continental Shelf Lands Act (OCSLA) (43 U.S.C. 331 et
seq.) established Federal jurisdiction over submerged lands on the
outer continental shelf (OCS) seaward for 5 km (3 mi) in order to
expedite exploration and development of oil and gas resources. The
OCSLA is implemented by the Bureau of Ocean Energy, Management,
Regulation and Enforcement (formerly the Minerals Management Service)
of the Department of the Interior. The OCSLA mandates that orderly
development of OCS energy resources be balanced with protection of
human, marine, and coastal environments. Specifically, Title II of the
OCSLA provides for the cancellation of leases or permits if continued
activity is likely to cause serious harm to life, including fish and
other aquatic life. It also requires economic, social, and
environmental values of the renewable and nonrenewable resources to be
considered in management of the OCS. Through consistency
determinations, any license or permit issued under the OCSLA must be
consistent with State coastal management plans (see also the Coastal
Zone Management Act below). Thus, the OCSLA helps to increase the
likelihood that projects on the OCS do not adversely impact Pacific
walruses or their habitats.
Oil Pollution Act of 1990
The Oil Pollution Act of 1990 (OPA) (33 U.S.C. 2701) provides
enhanced capabilities for oil spill response and natural resource
damage assessment by the Service. The OPA requires the Service to
consult on developing a fish and wildlife response plan for the
National Contingency Plan, provide input to Area Contingency Plans,
review Facility and Tank Vessel Contingency Plans, and conduct damage
assessments for the purpose of obtaining damages for the restoration of
natural resources injured from oil spills. However, we note that there
are limited abilities to respond to a catastrophic oil spill event
described in the plan (Alaska Regional Response Team 2002, pp. G-71, G-
72). The U.S. Coast Guard, despite planning efforts, has limited
offshore capability to respond in the event of a large oil spill in
northern or western Alaska, and we only marginally understand the
science of recovering oil in broken ice (O'Rourke 2010, p. 23).
Coastal Zone Management Act
The Coastal Zone Management Act of 1972 (CZMA) (16 U.S.C. 1451 et
seq.) was enacted to ``preserve, protect, develop, and where possible,
to restore or enhance the resources of the Nation's coastal zone.'' The
CZMA provides for the submission of a State program subject to Federal
approval. The CZMA requires that Federal actions be conducted in a
manner consistent with the State's Coastal Zone Management Plan (CZMP)
to the maximum extent practicable. Federal agencies planning or
authorizing an activity that affects any land or water use or natural
resource of the coastal zone must provide a consistency determination
to the appropriate State agency. The CZMA applies to walrus habitats of
northern and western Alaska. In Alaska, consistency determinations are
reviewed for compliance with the Alaska Coastal Management Program
(Alaska Stat. section 46.39-40). The Alaska Coastal Management Plan is
developed in partnership with Alaska's natural resource agencies, the
Alaska Department of Environmental Conservation, the ADFG, and the
Department of Natural Resources (Alaska Coastal Management Plan 2005,
p. A85). The CZMA applies to walrus habitats of northern and western
Alaska by ensuring that any permitted actions are consistent with the
State of Alaska's CZMP, which, among other things, sets standards that
require exposed high energy coasts to be managed so as to avoid,
minimize, or mitigate significant adverse impacts to the mix and
transport of sediments. As such, these requirements provide potential
protection to current or future coastal haulouts.
Alaska National Interest Lands Conservation Act
The Alaska National Interest Lands Conservation Act of 1980
(ANILCA) (16 U.S.C. 3101 et seq.) created or expanded National Parks
and National Wildlife Refuges in Alaska, including the expansion of the
Togiak National Wildlife Refuge (NWR) and the Alaska Maritime NWR. One
of the purposes of these National Wildlife Refuges under the ANILCA is
the conservation of marine mammals and their habitat. Walrus haulouts
at Cape Peirce and Cape Newenham are located within Togiak NWR while
haulouts at Cape Lisburne occur in the Alaska Maritime NWR. Access to
the Cape Peirce is tightly controlled through a permitted visitor
program. Refuge staff require that visitors must remain out of sight,
downwind, and a minimum of 107 m (100 yards) from walruses. Visitors
are advised that disturbances to walruses or seals are a violation of
the MMPA (Miller 2010, pers. comm.). Cape Newenham has no established
refuge visitor program, because public access is
extremely limited due to the presence of Department of Defense lands
surrounding the Cape. As discussed under Factor A above, the change in
the nature and location of walrus haulouts in response to changing ice
conditions is anticipated into the foreseeable future. Significant
portions of the Chukchi Sea coastal zone in Alaska are National
Wildlife Refuge lands created under ANILCA, and they have the ability
to provide haulout locations that are free from human disturbance.
Marine Protection, Research and Sanctuaries Act
The Marine Protection, Research and Sanctuaries Act (MPRSA) (33
U.S.C. 1401 et seq.) was enacted in part to ``prevent or strictly limit
the dumping into ocean waters of any material that would adversely
affect human health, welfare, or amenities, or the marine environment,
ecological systems, or economic potentialities.'' The MPRSA does not
itself regulate the take of walrus; however, it does help maintain
water quality, which likely benefits walrus prey.
Magnuson-Stevens Fishery Conservation and Management Act
The Magnuson Fishery Conservation and Management Act in 1976
(renamed the Magnuson-Stevens Fishery Conservation and Management Act
(MSFCMA)) (16 U.S.C. 1800 et seq.) established the North Pacific
Fishery Management Council (NPFMC), one of eight regional councils
established by the MSFCMA to oversee management of the U.S. fisheries.
With jurisdiction over the 2,331,000-sq-km (900,000-sq-mi) Exclusive
Economic Zone (EEZ) off Alaska, the NPFMC has primary responsibility
for groundfish management in the Gulf of Alaska (GOA) and Bering Sea
and Aleutian Islands (BSAI), including Pacific cod (Gadus
macrocephalus), pollock, mackerel (Pleurogrammus monopterygius),
sablefish (Anoplopoma fimbria), and rockfish (Sebastolobus and Sebastes
species) species harvested mainly by trawlers, hook and line,
longliners, and pot fishermen. In 2009, the NPFMC released its Fishery
Management Plan for Fish Resources of the Arctic Management Area,
covering all U.S. waters north of the Bering Strait. Management policy
for this region is to prohibit all commercial harvest of fish until
sufficient information is available to support the sustainable
management of a commercial fishery (NPFMC 2009, p. 3). The policy helps
to protect walrus from potential impacts of commercial fishery
Additionally, the Sustainable Fisheries Act of 1996 amended the
MSFCMA, requiring the NOAA to describe and identify Essential Fish
Habitat, which includes those waters and substrates necessary to fish
for spawning, breeding, feeding, or growth to maturity. ``Waters''
include aquatic areas and their associated physical, chemical, and
biological properties. ``Substrate'' includes sediment underlying the
waters. ``Necessary'' means the habitat required to support a
sustainable fishery and the managed species' contribution to a healthy
ecosystem. Spawning, breeding, feeding, or growth to maturity covers
all habitat types utilized by a species throughout its life cycle, and
includes not only the water column but also the benthos layers. The
NOAA's ``Final Rule for the implementation of the Fisheries of the
Exclusive Economic Zone off Alaska; Groundfish Fisheries of the Bering
Sea and Aleutian Islands Management Area,'' published July 25, 2008
(NOAA 2008, p. 43362), protects areas adjacent to walrus haulouts and
feeding areas from potential impacts of trawl fisheries. For example,
the St. Lawrence Island Habitat Conservation Area closes waters around
the St. Lawrence Island to federally permitted vessels using nonpelagic
trawl gear. Such closures provide important refuge for the walrus, but,
more importantly, protect feeding habitat from disturbance.
The walrus in Russia is a protected species managed primarily by
the Fisheries Department within the Ministry of Agriculture.
Regulations regarding the subsistence harvest of walrus were discussed
previously. There is currently no commercial harvest of walrus
authorized in Russia (Kochnev 2010, pers. comm.).
Important terrestrial haulout sites in Russia are also protected,
and human disturbance is minimized. For example, Wrangel Island, an
area which has seen large influxes of walrus, as discussed above, has
been a nature reserve since 1979 and prohibits human disturbance
(United Nations Environmental Program 2005, p. 1). Additionally, the
haulouts at Cape Kozhevnikov near the village of Ryrkaipyi and Cape
Vankarem near the village of Vankarem were recently granted protections
by the Government of Chukotka to minimize disturbance, and a local
conservation organization known as the ``UMKY Patrol'' has organized a
quiet zone and implemented visitor guidelines to reduce disturbance
(Patrol 2008, p. 1; Kavry 2010, pers. comm.).
State of Alaska
While the Service has the primary authority to manage Pacific
walrus in the United States, the State of Alaska has regulatory
programs that compliment Federal regulations and work in concert to
provide conservation for walrus and their habitats. For example, as
discussed above, the State's Coastal Zone Management Plan works to
ensure that beach integrity is maintained. Additionally, oil and gas
lease permits issued by the State of Alaska in State waters or along
the coastal plain contain specific requirements for Pacific walrus
that, for example, prohibit above-ground lease-related facilities and
structures within 1 mile inland from the coast, in an area extending 1
mile northeast and 1 mile southwest of the Cape Seniavin walrus haulout
(ADNR 2005, p. 3). In addition, walrus and their habitats are protected
in various State special-use areas. For example, the Walrus Island
State Game Sanctuary is a State of Alaska-managed conservation area
with regulations in place that allow only limited access to the
sanctuary, prohibit any disturbance of walrus, and limit access to
beaches and water. These regulations protect walrus and their haulouts
(5 AAC 92.066, Permit for access to Walrus Islands State Game
Summary of Factor D
As explained in Factor A, the sea-ice habitat of the Pacific walrus
has been modified by the warming climate, and sea-ice losses are
projected to continue into the foreseeable future. There currently are
no regulatory mechanisms in place to effectively reduce or limit GHG
emissions. This situation was considered as part of our analysis in
Factor A. Accordingly, there are no existing regulatory mechanisms to
effectively address loss of sea-ice habitat.
As explained in Factor B, harvest, while currently sustainable, is
identified as a threat within the foreseeable future because we
anticipate that harvest levels will continue at current levels while
the population declines due to sea-ice loss; as a result, the
proportion of animals harvested will increase. Harvest in Russia is
managed for sustainability through a quota system. Harvest in the
United States is well-monitored and limited to subsistence harvest by
Alaska Natives, with further restrictions on use and sale of walrus
parts; however, the U.S. harvest is not directly limited by quota.
Emerging local harvest management efforts offer a promising approach to
developing harvest management initiatives. Effectiveness of
such measures can be evaluated with existing harvest monitoring and
reporting programs. In the Bering Strait Region, where the vast
majority of U.S. harvest and 43 percent of the rangewide harvest
occurs, local ordinances recently adopted by two Native villages
reflect the important role of self-regulation in managing the
subsistence harvest, and will be important in the development of
harvest management strategies in the future. However, there are
currently no tribal, Federal, or State regulations in place to ensure
the likelihood that, as the population of walrus declines in response
to changing sea-ice conditions, the subsistence harvest of walrus will
occur at a reduced and sustainable level. As a result, we conclude that
current regulatory mechanisms are inadequate to address the threat of
subsistence harvest becoming unsustainable in the foreseeable future,
as the Pacific walrus population declines due to sea-ice habitat loss
and associated impacts.
While laws and regulations exist that help to minimize the effect
of other stressors on the Pacific walrus, there are no regulatory
mechanisms currently in place that adequately address the primary
threats of habitat loss due to sea-ice declines (Factor A) and
subsistence harvest (Factor B). As a result, we conclude that the
existing regulatory mechanisms do not remove or reduce the threats to
the Pacific walrus from the loss of sea-ice habitat and
Factor E. Other Natural or Manmade Factors Affecting Its Continued
We evaluated other factors that may have an effect on the Pacific
walrus, including pollution and contaminants; oil and gas exploration,
development, and production; commercial fisheries interactions;
shipping; oil spills; and icebreaking activities. The potential effects
of many of the stressors under this factor are tied directly to changes
in sea ice. Potential increases in commercial shipping due to the
opening of shipping lanes that have been unavailable in the past are
one example. In addition, oil and gas exploration and development
activities are in part dependent on ice conditions, as is the potential
for expanding commercial fisheries. Because the potential effects of
these stressors are related to sea-ice losses, our ability to reliably
predict the potential level and influence of these stressors is tied to
our ability to predict environmental changes associated with sea-ice
losses, as discussed previously under Factor A.
Pollution and Contaminants
Understanding the potential effects of contaminants on walruses is
confounded by the wide range of contaminants present, each with
different chemical properties and biological effects, and the differing
geographic, temporal, and ecological exposure regimes. Nevertheless,
Robards et al. (2009, p. 1) in their assessment of contaminant
information available for Pacific walruses conclude that Pacific
walruses contain generally low contaminant levels; however, an absence
of data limited definitive conclusions about the effects current
contaminant had on Pacific walruses.
Of particular concern in the Arctic are persistent organic
pollutants (POPs), because they do not break down in the environment
and are toxic. ``Legacy'' POPs (those no longer used in the United
States) include polychlorinated biphenyls (PCBs) and organochlorine
pesticides such as DDT, chlordanes, toxaphene, and mirex. POPS with
continued use include hexachlorocyclohexanes (HCHs). Although numerous
POPs have been detected in the Arctic environment, concentrations of
POPs found in Pacific walrus are relatively low (Seagars and Garlich-
Miller 2001, p. 129; Taylor et al. 1989, pp. 465-468) because walruses
generally feed at relatively lower trophic levels than other marine
mammals. In 1981, Atlantic walruses had the lowest concentrations of
organochlorines in any pinniped measured (Born et al. 1981, p. 255),
and recent data show walruses had much lower levels of brominated
compounds and perfluorinated sulfonates (PFSA) than other Arctic marine
mammals (Letcher et al., 2010, In press). Some Atlantic walrus
individuals and populations specialize in feeding on pelagic fish and
ringed seals, moving them higher in the food chain than the Pacific
walrus, resulting in greater POP concentrations (Dietz et al. 2000, p.
221). For example, PCBs and DDT concentrations in Pacific walruses were
lower than concentrations found in Atlantic walruses from Greenland and
Hudson Bay, Canada, collected in the 1980s (Muir et al. 1995, p. 335).
Heavy metals of concern in Arctic marine mammals include mercury
(Hg), cadmium, and lead. Defining mercury trends is complicated by
mercury's complex environmental chemistry, although in general
anthropogenic mercury is increasing in the Arctic, as it is globally
(AMAP 2005, p. 17), primarily due to combustion processes. Temporally,
mercury concentrations in fossils and fresh walrus teeth collected at
Nunavut in the Eastern Canadian Arctic were no higher in the 1980s and
1990s compared to A.D. 1200-1500, ``indicating an absence of industrial
Hg in the species at this location.'' Increases of mercury were seen in
beluga teeth from the Beaufort Sea over the same time span (Outridge et
al. 2002, p. 123). There was also no change in mercury in walruses from
Greenland from 1973 to 2000 (Riget et al. 2007, p. 76). Born et al.
(1981, p. 225) found low methyl mercury accumulation in Atlantic
walruses compared to seals in Greenland and the eastern Canadian
The presence of cadmium has been of concern to subsistence hunters
who eat Pacific walruses, though it does not appear to be having
effects on walrus health. Mollusks accumulate cadmium, so it is not
surprising that walruses had relatively high levels. However, Lipscomb
(1995, p. 1) found no histopathological (effects of disease on tissue)
effects in Pacific walrus liver and kidney tissues, although liver
concentrations were great enough to cause concern about contamination
levels, walrus health, and the consumption of walrus. Over the time
period 1981 to 1991, cadmium in Pacific walrus liver declined from 41.2
to 19.9 milligrams/kg dry weight (Robards 2006, p. 24).
Radionuclide (a radioactive substance) sources include atmospheric
fallout from Chernobyl, nuclear weapons testing, and nuclear waste
dumps in Russia (Hamilton et al. 2008, p. 1161). Pacific walrus muscle
had non-naturally occurring cesium 137 levels lower than did bearded
seals (Erignathus barbatus) sampled from the same area, and lower than
seals from Greenland sampled one to two decades earlier (Hamilton et
al. 2008, p. 1162). Barring new major accidents or releases, with decay
of anthropogenic radionuclides from fallout and Chernobyl and improved
regulation and cleanup of waste sources, radionuclide activities are
expected to continue to decline in Arctic biota (AMAP 2009, p. 66).
Tributyltin (TBT; from ship antifouling paints) is ubiquitous in
the marine environment (Takahashi et al. 1999, p. 50; Strand and Asmund
2003, p. 31), although TBT and its toxic metabolites are found at
greatest concentrations in harbors and near shore shipping channels
(Takahashi et al. 1999, p. 52; Strand and Asmund 2003, p. 34). Pacific
walruses will likely see increased exposure to this contaminant class
as shipping increases in their habitats as a result of longer ice-free
seasons due to climate change.
Climate-related change will affect long-range and oceanic transport
of contaminants, and may provide additional sources of contaminants.
Increasing water temperatures may increase methylation of mercury,
which increases the availability of mercury for bioaccumulation
(Sunderland et al. 2009, p. 1) and may release contaminants from
melting pack ice (Metcalf and Robards 2008, p. S153). It is projected
that Cesium 137 from nuclear weapons testing fallout and Chernobyl may
be liberated from storage in trees as the incidence of forest fires
increases due to climate change (AMAP 2009, p. 66).
Although few data exist with which to evaluate the status of the
Pacific walrus population in relation to contaminants, information
available indicates that Pacific walruses have generally low
concentrations of contaminants of concern. Further, based on the
general observations of a lack of effect on individual animals, there
is currently no evidence of population-level effects in walruses from
contaminants of any type. Climate change, with projected increases in
mobilization of contaminants to and within the Arctic, combined with
potential changes in Pacific walrus prey base, may lead to increased
exposure. However, potential effects are likely to be limited by the
trophic status and distribution of walruses: As benthic feeders that
specialize on prey lower in the food web, walruses would have a low
rate of bioaccumulation and therefore limited exposure to contaminants.
Based on our estimation of low current contaminant loads and the
likelihood of minimal future exposure as walruses feed on lower trophic
levels, we conclude that contaminants are not a threat now and are not
likely to be a threat to the Pacific walrus population in the
Oil and Gas Exploration, Development, and Production
Oil and gas related activities have been conducted in the Beaufort
and Chukchi Seas since the late 1960s, with most activity occurring in
the Beaufort Sea (USFWS 2008, p. 33212). Three existing projects are
located off the coast of Alaska in the Beaufort Sea (Endicott,
Northstar, and Oooguruk). Current and foreseeable future activity in
the Chukchi Sea is related to Lease Sale 193, the first Chukchi Sea
lease sale since 1991 (MMS 2008, p. 1). While no development of leases
issued pursuant to the lease sale has occurred to date, future activity
is anticipated. Our ability to predict effects of these activities on
walrus is based, in part, on reasonably foreseeable development
scenarios prepared for this lease sale, which project exploration,
development, and production activities to last through roughly 2049
(USFWS, Final Biological Opinion for Beaufort and Chukchi Sea Program
Area Lease Sales and Associated Seismic Surveys and Exploratory
Drilling, Anchorage, Alaska, September 3, 2009, pp. 10-11).
In the Chukotka Russia region, the oil and gas industry is
targeting regions of the Bering and Chukchi Seas for exploration.
Recently, there has been renewed interest in exploring for oil and gas
in the Russian Chukchi Sea, as new evidence suggests that the region
may harbor large reserves. In 2006, seismic exploration was conducted
in the Russian Chukchi to explore for economically viable oil and gas
reserves (Frantzen 2007, p. 1).
Currently, Pacific walruses do not normally range into the Beaufort
Sea, although individuals and small groups have been observed there.
From 1994 to 2004, industry monitoring programs recorded a total of 9
walrus sightings, involving a total of 10 animals. No disturbance
events or lethal takes have been reported to date (USFWS 2008, p.
33212). Because of the small numbers of walruses encountered by past
and present oil and gas activity in the Beaufort Sea, impacts to the
Pacific walrus population appear to have been minimal (USFWS 2008, p.
33212). Even with less ice, it is unlikely that walrus numbers will
increase significantly in the Beaufort Sea, as habitat is limited by a
relatively narrow continental shelf, which results in deep and less-
productive waters. Therefore, we do not anticipate significant
interactions with, or impacts from, oil and gas activities in the
Beaufort Sea on the Pacific walrus population.
Pacific walruses are seasonally abundant in the Chukchi Sea.
Exploratory oil and gas operations in the Chukchi Sea have routinely
encountered Pacific walruses; however, potential impacts to walruses
are regulated through the MMPA. Specifically, incidental take
regulations (ITRs) have been promulgated for the non-lethal, incidental
take of walruses from oil and gas exploration activities in the Chukchi
Sea, including geophysical, seismic, exploratory drilling and
associated support activities for the 5-year period ending in June
2013. In a detailed analysis of the effects of such activities,
including noise, physical obstructions, human encounters, and oil
spills, the Service concluded that exploration activities would be
sufficiently limited in time and scope that they would result in the
take of only small numbers of walruses with no more than a negligible
impact on the stock (73 FR 33212 (2008)). Prior to commencing
exploration activities, operators are currently required by the Bureau
of Ocean Energy, Management, Regulation and Enforcement (BOEMRE,
formerly MMS) to obtain letters of authorization (LOA) pursuant to the
ITRs or an incidental harassment authorization (IHA) (Wall 2011, pers.
comm.). If operators commence operations without such authorization,
their operations may be shut down, (Wall 2011, pers. comm.), and any
take of walrus would be in violation of the MMPA.
While we anticipate oil and gas exploration activities to occur in
the Chukchi Sea in the foreseeable future, we expect industry to
request that the ITRs be renewed, so that any non-lethal, incidental
take associated with exploration is authorized under the MMPA. The ITRs
could not be renewed, and LOAs could not be issued, unless a
determination were made that the activities would result in the take of
only small numbers of walrus and have a negligible impact on the stock.
Monitoring studies performed to date have documented minimal
effects of various exploration activities on walruses (USFWS 2008, p.
33212). In 1989 and 1990, aerial surveys and vessel-based observations
of walruses were carried out to examine the animals' response to
drilling operations at three Chukchi Sea prospects. Aerial surveys
documented several thousand walruses (a small percentage of the
estimated population) in the vicinity of the drilling prospects. The
monitoring reports concluded that: (1) Walrus distributions were
closely linked with pack ice; (2) pack ice was near active drill
prospects for relatively short time periods; and (3) ice passing near
active prospects contained relatively few animals. Walruses either
avoided areas of operations or were passively carried away by the ice
floes, and because only a small proportion of the population was near
the operations, and for short periods of time, the effects of the
drilling operations on walruses were limited in time, area, and
proportion of the population (USFWS 2008, p. 33212). However, if walrus
are forced to avoid areas of operations and associated disturbance by
abandoning ice haulouts and swimming to other areas, they will likely
experience increased energetic costs related to active swimming as
opposed to passive transport on ice floes.
Disturbances caused by vessel and air traffic may cause walrus
groups to abandon land or ice haulouts. One study
suggests that walruses may be tolerant of ship activities; Brueggeman
et al. (1991, p. 139) reported that 75 percent of walruses encountered
by vessels in the Chukchi Sea exhibited no reaction to ship activities
within 1 km (0.6 mi) or less. This conclusion is corroborated by
another study, which reported observations that walruses in water
generally show little concern about potential disturbance from
approaching vessels and will dive or swim away if a vessel is nearing a
collision with them (Fay et al. 1984, p. 118).
Open-water seismic exploration, which produces underwater sounds
typically with air gun arrays, may potentially affect marine mammals.
Walruses produce a variety of sounds (grunts, rasps, clicks), which
range in frequency from 0.1 to 10.0 Hertz (Hz, sine wave of a sound)
(Richardson et al. 1995, p. 108). The effects of seismic surveys on
walrus hearing and communications have not been studied. Seismic
surveys in the Beaufort and Chukchi Seas will not impact vocalizations
associated with breeding activity (one of the most important times of
communication), because walruses do not currently breed in the open
water areas that are subject to survey. Injury from seismic surveys
would likely occur only if animals entered the zone immediately
surrounding the sound source (Southall et al. 2007, p. 441). Walrus
behavioral responses to dispersal and diving vessels associated with
seismic surveys were monitored in the Chukchi Sea OCS in 2006. Based
upon the transitory nature of the survey vessels, and the behavioral
reactions of the animals to the passage of the vessels, we conclude
that the interactions resulted in temporary changes in animal behavior
with no lasting impacts to the species (Ireland et al. 2009, pp. xiii-
Future seismic surveys are anticipated to have minimal impacts to
walrus. Surveys will occur in areas of open water, where walrus
densities are relatively low. Monitoring requirements (vessel-based
observers) and mitigation measures (operations are halted when close to
walrus) in U.S. waters are expected to minimize any potential
interactions with large aggregations of walruses. Because seismic
operations likely would not be concentrated in any one area for
extended periods, any impacts to walruses would likely be relatively
short in duration and have a negligible overall impact on the Pacific
Currently, there are no active offshore oil and gas developments in
the U.S. Bering or Chukchi Seas. Therefore, the risk of an oil spill is
low at the present time. The potential for an oil spill increases as
offshore oil and gas development and shipping activities increase. No
large oil spills have occurred in areas inhabited by walruses; however,
a large oil spill could result in acute mortalities and chronic
exposure that could substantially reduce the Pacific walrus population
for many years (Garlich-Miller et al. 2011, Section 184.108.40.206.3 ``Oil
Spills''). A spill that oiled coastal haulouts occupied by females and
calves could be particularly significant and could have the potential
to impact benthic communities upon which walruses depend. As discussed
below, oil spill cleanup in the broken-ice and open-water conditions
that characterize walrus habitat would be more difficult than in other
areas, primarily because effective strategies have yet to be developed.
The Coast Guard has no offshore response capability in northern or
western Alaska (O'Rourke 2010, p. 23).
According to BOEMRE, if oil and gas development of leases issued
pursuant to Chukchi Lease Sale 193 occurs, the chance of one or more
large oil spills (greater than or equal to 1,000 barrels) occurring
over the production life of the development is between 35 and 40
percent (MMS 2007, p. IV-156). However, the estimated probability that
oil reserves sufficient for development will be discovered range from 1
to 10 percent (MMS 2007, p. IV-156), reducing the chance of a large oil
spill to 0.33 to 4 percent.
Our analysis of oil and gas development potential and subsequent
risks was based on the analysis BOEMRE (MMS 2007, p. 1-631) conducted
for the Chukchi Sea lease sales. Following the Deepwater Horizon
incident in the Gulf of Mexico, offshore oil and gas activities have
come under increased scrutiny. Policy and management changes are under
way within the Department of the Interior that will likely affect the
timing and scope of future offshore oil and gas activities. In
addition, BOEMRE has been restructured to increase the effectiveness of
oversight activities, eliminate conflicts of interest, and increase
environmental protections (USDOI 2010, p. 1). As a result, we
anticipate that the potential for a significant oil spill will remain
small; however, we recognize that should a spill occur, there are no
effective strategies for oil spill cleanup in the broken-ice conditions
that characterize walrus habitat. In addition, the potential impacts to
Pacific walrus from a spill could be significant, particularly if
subsequent cleanup efforts are ineffective. Potential impacts would be
greatest if walrus are aggregated in coastal haulouts where oil comes
to shore. Overall, the chance of a large oil spill occurring in the
Pacific walrus' range in the foreseeable future, however, is considered
In summary, oil and gas activities have occurred sporadically
throughout the range of the Pacific walrus. Specific studies on the
effects of exploratory drilling activities and associated shipping and
seismic surveys have documented minimal effects on walrus--namely,
transitory behavioral changes that were temporary in nature.
Exploration activities are currently regulated under the MMPA, and the
take of walrus during exploration activities is only authorized if
operators have first obtained an LOA or an IHA. These authorizations
are only issued for the non-lethal, incidental take of walrus, where
the activities are considered likely to result in the take of small
numbers of walrus with a negligible impact on the stock. We expect that
future exploration to be similarly regulated under the MMPA. Therefore,
we conclude that impacts of oil and gas exploration likely to occur
over the foreseeable future will have minimal effects on walruses.
Further, although a significant oil spill in the Chukchi Sea from
exploration, development or production activities could have a
detrimental impact on Pacific walrus, depending on timing and location,
the potential for such a spill is low. As a result, we conclude that
oil and gas exploration, development, and production are not threats to
the Pacific walrus now, nor are they likely to become threats in the
Commercial fisheries occur primarily in ice-free waters and during
the open-water season, which limits the overlap between fishery
operations and walruses. Where they do overlap, fisheries may impact
Pacific walruses through interactions that result in the incidental
take of walrus or through competition for prey resources or destruction
of benthic prey habitat. A complete list of fisheries is published
annually by NOAA Fisheries. The most recent edition (NOAA 2009a, p.
58859), showed about nine fisheries that have the potential to occur
within the range of the Pacific walrus.
Currently, incidental take in the form of mortality from commercial
fishing is low. Pacific walruses occasionally interact with trawl and
longline gear of groundfish fisheries. In Alaska each year, fishery
observers monitor a percentage of commercial fisheries and report
injury and mortality of marine
mammals affected incidental to these operations. Incidental mortality
to Pacific walruses during 2002-2006 was recorded for only one fishery,
the Bering Sea/Aleutian Island flatfish trawl fishery, which is a
Category II Commercial Fishery with 34 vessels or persons. During the
years 2002-2006, observer coverage for this fishery averaged 64.7
percent. The mean number of observed mortalities was 1.8 walrus per
year, with a range of 0 to 3 walrus per year. The total estimated
annual fishery-related incidental mortality in Alaska was 2.66 walrus
per year (USFWS 2010, pp. 3-4).
In addition to incidental take from fishing activities, however,
fishery vessel traffic has the potential to take Pacific walruses
through collisions and disturbance of resting, foraging, or travelling
behaviors. We consider the likelihood of collisions between fishing
vessels and walruses to be very low, however, as we unaware of any
documented ship strikes, and it has been observed that walruses
typically dive or swim off to the side if a shipping vessel comes close
to colliding with them (Fay et al. 1984, p. 118). Fisheries occurring
near terrestrial haulouts may affect animals approaching, leaving, or
resting at the haulouts.
The Bristol Bay region in the Bering Sea is home to some of the
largest U.S. land haulouts and several fisheries. For some haulouts,
regulations are in place to minimize disturbance. Round Island is
buffered from all fishing activities by a 0-to-3-nautical-mile ``no
transit'' closure. Capes Peirce and Newenham and Round Island are
buffered from fishing activities in Federal waters from 3 to 12
nautical miles; however, this buffer only applies to vessels with
Federal fisheries permits. The haulout at Hagemeister Island has no
protection zone in either Federal or State waters. Large catcher/
processer vessels associated with the yellowfin sole fishery, as well
as smaller fishing vessels 32 ft or less in length routinely pass
between the haulout and the mainland to a site for offloading product
to foreign vessels. Anecdotal reports indicate potential disturbance of
walruses using the Hagemeister haulout (Wilson and Evans 2009b, p. 28).
To address concerns of disturbance associated with the yellowfin sole
fleet, the Service has engaged the North Pacific Fisheries Management
Council to examine alternatives to provide increased protection for the
haulout at Hagemeister Island (Wilson and Evan 2009a, pp. 1-23);
however, no specific measures have been implemented. The haulout at
Cape Seniavin currently has no Federal or State protection zones. No
Federal fisheries occur near Cape Seniavin, but State of Alaska-managed
salmon fisheries do occur in the immediate vicinity and pose a
potential for disturbance. In general, however, within Bristol Bay, the
proportion of walruses potentially affected is small relative to the
population. The population is also comprised predominantly of males,
which are less susceptible to trampling injuries as a result of
disturbance; however, repeated disturbance events have the potential to
result in haulout abandonment.
State-managed nearshore herring and salmon gillnet fisheries also
have the potential to take walruses. The ADFG does not have an observer
or self-reporting program to record marine mammal interactions, but it
is believed that gear interactions with walruses have not occurred in
the recent past (Murphy 2010, pers. comm.; Sands 2010, pers. comm.).
Spotter planes used in the spring herring fishery in Bristol Bay have
the potential to cause disturbance at terrestrial haulouts. To mitigate
this potential, the Service developed and distributed guidelines for
appropriate use of aircraft within the vicinity of Bristol Bay walrus
haulouts (USFWS 2009, p. 1), and these were in effect during the
In summary, given the current low rates of walrus encounters and
deaths associated with commercial fishing, we expect that any increase
in the level of fishery-related mortality to walrus will occur at a
very low level relative to the total walrus population. Similarly,
although walrus may be subject to disturbance from commercial fishing,
the proportion of walrus affected is low, and efforts are under way to
minimize the impacts. Accordingly, we do not consider fishery-related
take of walrus to be a threat to the Pacific walrus population now or
in the foreseeable future.
Commercial fisheries may also impact walruses through competition
for prey resources or destruction of benthic prey habitat. With regard
to competition, there is little overlap between commercial fish species
and Pacific walrus prey species. The principal prey items consumed by
weaned walruses are bivalves, gastropods, and polychaete worms (Fay
1982, p. 145; Sheffield and Grebmeier 2009, p. 767). Fay (1982, pp.
153-154) notes that the scarcity in walruses of endoparasites of known
fish origin indicates that walruses rarely ingest fish. Fay (1982, pp.
152,154) also notes that various authors have reported occasionally
finding several different crab species in walrus stomachs, but
apparently at low frequency. Thus, direct competition for prey from
commercial fisheries does not appear to be a threat to the Pacific
walrus population now or in the foreseeable future.
Commercial fisheries--specifically pelagic (mid-water trawl) and
nonpelagic (bottom trawl) fisheries--have the potential to indirectly
affect walruses through destruction or modification of benthic prey or
their habitat. Pelagic or mid-water trawls make frequent contact with
the bottom, as evidenced by the presence of benthic species (e.g.,
crabs, halibut) that are brought up as bycatch. NFMS estimates that
approximately 44 percent of the area shadowed by the gear receives
bottom contact from the footrope (NMFS 2005, pp. B-11). The majority of
the pelagic trawl effort in the eastern Bering Sea is directed at
walleye pollock in waters of 50-300 m (164-960 ft) (Olsen 2009, p. 1).
The area north of Unimak Island along the continental shelf edge
receives high fishing effort (Olsen 2009, p. 1). This puts the majority
of pelagic fishing effort on the periphery of walrus-preferred habitat,
as walruses are usually found over the continental shelf in waters of
100 m (328 ft) or less (Fay and Burns 1988, pp. 239-240; Jay et al.
2001, p. 621).
Nonpelagic fisheries also have the potential to indirectly affect
walruses by destroying or modifying benthic prey or their habitat, or
both. The predominant effects of nonpelagic trawl include ``smoothing
of sediments, moving and turning of rocks and boulders, resuspension
and mixing of sediments, removal of sea grasses, damage to corals, and
damage or removal of epigenetic organisms'' (Mecum 2009, p. 57).
Numerous studies on the effects of trawl gear on infauna have been
conducted, and all note a reduction in mass (Brylinsky et al. 1994, p.
650; Bergman and van Santbrink 2000, p. 1321; McConnaughey et al. 2000,
p. 1054; Kenchington et al. 2001, p. 1043). Two such studies comparing
microfaunal populations between unfished and heavily fished areas in
the eastern Bering Sea reported that, overall, the heavily trawled and
untrawled areas were significantly different. In relation to walrus
prey, the abundance of neptunid snails was significantly lower in the
heavily trawled area, and mean body size was smaller, as was the trend
for a number of bivalve species (Macoma, Serripes, Tellina), indicating
a general decline in these species. The abundance of Mactromeris was
greater in the heavily trawled area, but mean body size was smaller
(McConnaughey et al. 2000, pp. 1381-1382; McConnaughey et al. 2005, pp.
The areas open to nonpelagic trawling, however, are limited. The
Final Environmental Impact Statement (EIS) for Essential Fish Habitat
Identification and Conservation in Alaska concluded that nonpelagic
trawling in the southern Bering Sea has long-term effects on benthic
habitat features, but little impact on fish stock productivity. The EIS
concludes that the reduction of infaunal and epifanual prey for managed
fish species would be 0 to 3 percent (NMFS 2005, p. 10; Mecum 2009, p.
47). While not a direct measure of impacts to walrus prey, the analysis
provides some insight on the level of impact to benthic species and
indicates that impacts are likely to be minimal.
Nonpelagic trawls are designed to remain on the bottom of the ocean
floor, but they may bring up walrus prey items as bycatch, albeit in
very small quantities. Wilson and Evans (2009, p. 15) report bycatch of
walrus prey items in the nonpelagic trawl fishery in the Northern
Bristol Bay Trawl Area (NBBTA). Data were collected through the NMFS
Fisheries Observer program and are aggregated for the years 2001 to
2009. Bivalves (mussels, oysters, scallops, and clams) accounted for
334 kg (735 lb) of the 457 kg (1005 lb) (73 percent) of total bycatch
reported; snails, which are consumed by walruses, were listed as a
bycatch species, but no amounts were reported. This level of bycatch is
very low relative to the total amount of prey consumed by walrus. The
NMFS is currently developing regulations to require the use of modified
nonpelagic trawl gear in the Bering Sea subarea for the flatfish
fishery and for nonpelagic trawl gear fishing in the northern Bering
Sea subarea (Brown 2010, pers. comm.), which will likely reduce impacts
on walrus prey. When implemented, the regulations will reopen an area
within the NBSRA to modified gear nonpelagic trawl fishing (Brown 2010,
pers. comm.; Mecum 2009, pp. 1-194).
Ecosystem shifts in the Bering Sea are expected to extend the
distribution of fish populations northward and, along with this shift,
nonpelagic bottom trawl fisheries are also expected to move northward
(NOAA 2009b, p. 1). Because we currently lack information on benthic
habitats and community ecology of the northern Bering Sea, we are
unable to forecast the specific impacts that may occur from nonpelagic
bottom trawling within this area (NOAA 2009b, p. 1) and how it may
affect the Pacific walrus.
Commercial fisheries in all U.S. waters north of the Bering Strait
are covered by the Fishery Management Plan for Fish Resources of the
Arctic Management Area, which was released by the NPFMC in 2009.
Management policy for this region is to prohibit all commercial harvest
of fish until sufficient information is available to support the
sustainable management of a commercial fishery (NPFMC 2009, p. 3). At
some point, the Arctic Management Area may be opened to commercial
fishing, but to date the NPFMC has taken a conservative stance. It is
unclear whether the Arctic Management Area will open to commercial
fishing at all, and if so, when it would be opened. If commercial
fishing does open up in this area, however, we would work with the
NPFMC to ensure that any necessary measures to minimize negative
effects to Pacific walrus are implemented.
Accordingly, although commercial fisheries--specifically pelagic
and nonpelagic trawl fisheries--have the potential to indirectly affect
walruses through destruction or modification of benthic prey or their
habitat, those fisheries do not appear to be a threat to Pacific walrus
now or in the foreseeable future, because of limited overlap between
the areas currently open to trawling and areas of walrus prey habitat
as well as ongoing efforts to minimize detrimental impacts to walrus
prey and benthic habitat.
In summary, we find that commercial fisheries have limited overlap
with walrus distribution, and reported direct takes are nominal.
Indirect effects on walruses are also limited, with some site-specific
potential effects to walrus near terrestrial haulouts in Bristol Bay.
Indirect effects to prey and benthic habitats due to various types of
trawls occur, but are limited with respect to overlap with the range of
walrus and walrus feeding habitat. We did not identify any direct
competition for prey resources between walruses and fisheries. In
addition, as fisheries currently do not occur in the Chukchi Sea, they
are not considered a serious threat to walrus at this time. We
recognize the potential future interest by the fishing industry to
initiate fisheries further north as fish distribution changes in
association with predicted changes in ocean conditions. However, based
on the limited fishing-related impacts to walrus that have occurred in
other areas to date, and the active engagement of the NPFMC through the
Arctic Fisheries Management Plan, we conclude that commercial fishing
is not now a threat to Pacific walrus and is not likely to become a
threat in the foreseeable future.
Commercial shipping and marine transportation vessels include oil
and gas tankers, container ships, cargo ships, cruise ships, research
vessels, icebreakers, and commercial fishing vessels. These vessels may
travel to or from destinations within the Arctic (destination traffic),
or may use the Arctic as a passageway between the Atlantic and Pacific
Oceans (nondestination traffic). While the level of shipping activity
is currently limited, the potential exists for increased activity in
the future if changes in sea-ice patterns open new shipping lanes and
result in a longer navigable season. Whether, and to what extent,
marine transportation levels may change in the Arctic depends on a
number of factors, including the extent of sea-ice melt, global trade
dynamics, infrastructure development, the safety of Arctic shipping
lanes, the marine insurance industry, and ship technology. Given these
uncertainties, forecasts of future shipping levels in the Arctic are
highly speculative (Arctic Council 2009, p. 1).
Two major shipping lanes in the Arctic intersect the range of
Pacific walrus: The Northwest Passage, which runs parallel to the
Alaskan Coast through the Bering Strait up through the Canadian Arctic
Archipelago; and the Northern Sea Route, which refers to a segment of
the Northeast Passage paralleling the Russian Coast through the Bering
Strait and into the Bering Sea (Garlich-Miller et al. 2011, Section
220.127.116.11 ``Scope and Scale of Shipping'').
Shipping levels in the Northwest Passage and Northern Sea Route are
highly dependent on the extent of sea-ice cover. Walrus occur along
both of these routes where they pass through the Bering Sea, Bering
Strait, and Chukchi Sea. Given the dependence of shipping activities on
the absence of sea ice, shipping levels are seasonally variable. Almost
all activity occurs in June through September, and to a lesser extent,
October and November, and April and May. Most walrus are in the Chukchi
Sea during the height of the shipping season, although at times they
are associated with sea ice or terrestrial haulouts. There is currently
no commercial shipping or marine transportation in December through
March (Arctic Council 2009, p. 85).
Based on predicted sea-ice loss (Douglas 2010, p. 12), the
navigation period in the Northern Sea Route is forecast to increase
from 20-30 days to 90-100 days per year by 2100. Other factors that may
lead to increased vessel traffic in the Arctic, in addition to reduced
sea ice, include increased oil
and gas development, Arctic community population growth and associated
development, and increased tourism (Brigham and Ellis 2004, pp. 8-9;
Arctic Council 2009, p. 5).
No quantitative analyses of changes in shipping levels currently
exist. Both the Arctic Marine Shipping Assessment (AMSA) and the Arctic
Marine Transport Workshop note that the greatest potential for
increased shipping and marine transportation is the potential use of
the Arctic as an alternative trade route connecting the Atlantic and
Pacific Oceans. The Northwest Passage is not considered a viable Arctic
throughway, given that the oldest and thickest sea ice in the Arctic is
pushed into the western edge of the Canadian Arctic Archipelago, making
the passage dangerous to navigate (Arctic Council 2009, p. 93).
However, the passage was open in 2007 and 2010, due to ice-free
The broad range of future shipping scenarios described in the AMSA
and the Arctic Marine Transport Workshop underscore the uncertainties
regarding future shipping levels. The AMSA notes that while the
reduction in sea ice will provide the opportunity for increased
shipping levels, ultimately it is economic factors, such as the
feasibility of utilizing the Northern Sea Route as an alternative
connection between the Atlantic and Pacific Oceans, that will determine
future shipping levels (Arctic Council 2009, pp. 120-121).
Increased shipping in the Bering and Chukchi Seas has the potential
to impact Pacific walrus during the spring, summer, and fall seasons.
An increase in shipping will result in increased potential for
disturbance in the water and at terrestrial haulouts. According to
Garlich-Miller et al. (2011, Section 18.104.22.168.3 ``Summer/Fall''), recent
trends suggest that most of the Pacific walrus population will be
foraging in open water from coastal haulouts along the Chukotka coast
during the shipping season. Because the Northern Sea Route passes
through this area, it is reasonable to expect walruses may be
encountered along this route (Garlich-Miller et al. 2011, Figure 9).
According to one study, however, walruses may be tolerant of ship
activities, as 75 percent of walruses encountered by vessels in the
Chukchi Sea exhibited no reaction to ship activities within 1 km (0.6
mi) or less (Brueggeman et al. 1991, p. 139). This is confirmed by
another study, which noted that walruses in water have been observed to
generally show little concern about potential disturbance from
approaching vessels, unless the ship came in very close proximity to
them, in which case they dove or swam off to the side (Fay et al. 1984,
p. 118). Therefore, we expect disturbance to walruses from shipping to
be minimal. In situations where negligible impacts to a small number of
walrus are anticipated from repeated displacement from a preferred
feeding area, for example, or noise disturbance at haulouts, incidental
take regulations could potentially be developed for U.S. vessels to
permit take caused by shipping activities, which are subject to the
MMPA. These activities likely would require mandatory monitoring and
mitigation measures designed to minimize effects to walrus through
vessel-based observers to avoid collisions and disturbance.
As a result, shipping is not currently a threat to the Pacific
walrus population, because shipping occurs at low levels, and shipping
in support of other activities (e.g., oil and gas exploration) is
sufficiently regulated and mitigated by MMPA incidental take
regulations. Shipping may increase in the future, but shipping lanes
are typically limited to narrow corridors, and disturbance from such
activities is expected to be low. Moreover, given the uncertainties
identified related to potential future shipping activities, we conclude
that increased shipping activities are unlikely to cause population-
level effects to the Pacific walrus in the foreseeable future. In
addition, take provisions of the MMPA can be effective in regulating
shipping that may disturb haulouts and interrupt foraging activity in
To date, there have been relatively few oil spills caused by marine
vessel travel in the Bering and Chukchi seas. Within the seasonal range
of walrus, there were approximately six vessel oil spill incidents
between 1995 and 2004: two caused by fires, two by machinery damage or
failure, one by grounding, and one by damage to the vessel. These
incidents were small in scale and did not cause widespread impacts to
walrus or their habitat. In general, the pattern of past vessel
incidents corresponds to areas of high vessel traffic. Given
anticipated increases in marine vessel travel within the range of
Pacific walrus due to sea-ice decline, it is likely that the number of
vessel incidents will increase in the foreseeable future.
Oil spill response for walruses, and for wildlife in general, can
be broken into three phases (Alaska Regional Response Team 2002, p.
G1). Phase One is focused on eliminating the source of the spill,
containing the spilled oil, and protecting environmentally sensitive
areas. Phase Two involves efforts to herd or haze potentially affected
wildlife away from the spill area. Phase Three, the most involved and
most infrequently undertaken phase of oil spill response for wildlife,
includes the capture and rehabilitation of oiled individuals.
Even under the most stringent control systems, some tanker spills,
pipeline leaks, and other accidents are likely to occur from equipment
leaks or human error (O'Rourke 2010, p. 16). The history of oil spills
and response in the Aleutian Islands raises concerns for potential
spills in the Arctic region: ``The past 20 years of data on response to
spills in the Aleutians has also shown that almost no oil has been
recovered during events where attempts have been made by the
responsible parties or government agencies, and that in many cases,
weather and other conditions have prevented any response at all''
(O'Rourke 2010, p. 23). Moreover, the Commander of the Coast Guard's
17th District, which covers Alaska, noted in an online journal that ``
* * * we are not prepared for a major oil spill [over 100,000 gallons]
in the Arctic environment. The Coast Guard currently has no offshore
response capability in northern or western Alaska and we only dimly
understand the science of recovering oil in broken ice'' (O'Rourke
2010, p. 23). The behavior of oil spills in cold and icy waters is not
well understood (O'Rourke 2010, p. 23). Cleaning up oil spills in ice-
covered waters will be more difficult than in other areas, primarily
because effective strategies have yet to be developed.
The Arctic conditions present several hurdles to oil cleanup
efforts. In colder water temperatures, there are fewer organisms to
break down the oil through microbial degradation and oil evaporates at
a slower rate. Although slower evaporation may allow for more oil to be
recovered, evaporation removes the lighter, more toxic hydrocarbons
that are present in crude oil (O'Rourke 2010, p. 24). The longer the
oil remains in an ecosystem, the more opportunity there is for
exposure. Oil spills may get trapped in ice, evaporating only when the
ice thaws, and in some cases, oil could remain in the ice for years.
Icy conditions enhance emulsification--the process of forming different
states of water in oil, often described as ``mousse.'' Emulsification
creates oil cleanup challenges by increasing the volume of the oil/
water mixture and the mixture's viscosity (resistance to flow). The
latter change creates particular problems for conventional removal and
pumping cleanup methods (O'Rourke 2010, p. 24). Moreover, two of the
major nonmechanical recovery methods--in-
situ burning and dispersant application--may be limited by the Arctic
conditions and lack of logistical support such as aircraft, vessels,
and other infrastructure (O'Rourke 2010, p. 24).
As stated earlier, vessel-related spills were, and will likely
continue to be, small in scale with localized impact to walrus and
their habitat. A large-scale spill could have a major impact on the
Pacific walrus population, depending on the spill and location relative
to coastal aggregations. However, at present the chance of a large oil
spill occurring in the Pacific walrus' range in the foreseeable future
is considered low. Because most oil spills will have only localized
impact to walrus, and the chance of a large-scale spill occurring in
the walrus' range in the foreseeable future is low, oil spills do not
appear to be a threat to Pacific walrus now or in the foreseeable
Icebreaking activities can create noise that causes marine mammals
to avoid areas where these activities are occurring. Further,
icebreaking activities may increase the risk of oil spills by
increasing vessel traffic in ice-filled waters. Given that marine
mammals, including walrus, have been found to concentrate in and around
temporary breaks in the ice created by icebreakers, there may be
greater environmental impact associated with an oil spill involving an
icebreaker or a vessel operating in a channel cleared by an icebreaker.
Currently, Russian and Canadian icebreakers are used along the
Northern Sea Route and within the Canadian Arctic Archipelago to clear
passageways utilized by commercial shipping vessels (Arctic Council
2009, p. 74), primarily in the summer months. The United States does
not currently engage in icebreaking activities for navigational
purposes in the Arctic (NRC 2005, p. 16). There are no current U.S. or
State of Alaska regulations on icebreaking activities, mainly because
icebreaking along the Alaskan Coast is minimal and usually carried out
by the Coast Guard. However, in the last few years, oil and gas
exploration activities in the Beaufort and Chukchi Seas have used
privately contracted icebreakers in support of their operations.
Icebreaking activities may increase in the future, given increases
in commercial shipping and marine transportation. In particular, the
establishment of the Northern Sea Route as a viable alternative trade
route connecting the Atlantic and Pacific Oceans is contingent on,
among other factors, the availability of a reliable government or
private icebreaking fleet to clear the entire Route and provide
predictable open shipping lanes (Arctic Marine Transport Workshop 2004,
p. 1; Arctic Council 2009, p. 20). Although there are no current
regulations on icebreaking activities in the Arctic, voluntary
guidelines addressing icebreaking activities could be included as part
of unified, multilateral regulation on Arctic shipping. According to
the U.S. Department of Transportation, the International Maritime
Organization (IMO) is considering developing icebreaking guidelines.
Icebreaking is currently not a threat to the Pacific walrus
population, because of the limited amount of icebreaking activity,
current regulations associated with shipping in support of other
activities (e.g., oil and gas development), and the relatively narrow
corridors in which the activities occur. Shipping activity and
associated icebreaking are predicted to increase in the future, but the
magnitude and rate of increase are unknown and dependent on both
economic and environmental factors. Given the uncertainties identified
related to potential future shipping activities, the available
information does not enable us to conclude that these activities will
cause population-level effects to the Pacific walrus in the foreseeable
Both the Service and USGS BN models included oil and gas
development, commercial fisheries, and shipping as stressors (Garlich-
Miller et al. 2011, Section 3.8.5 ``Other Natural or Human Factors'';
Jay et al. 2010b, p. 37). The USGS model also included air traffic and
shipping activities simultaneously (Jay et al. 2010b, p. 37). In both
models, these stressors had little influence on model outcomes
(Garlich-Miller et al. 2011 Section 3.8.5 ``Other Natural or Human
Factors''; Jay et al. 2010b, pp. 85-86, respectively).
Summary of Factor E
Based on our estimation of low current contaminant loads and the
likelihood of minimal future exposure as walruses feed on lower trophic
levels, we conclude that contaminants are not a threat now and are not
likely to be a threat to the Pacific walrus population in the
foreseeable future. Oil and gas exploration, development, and
production are currently not a threat to the Pacific walrus and are not
expected to be in the foreseeable future, due to the anticipated
increased scrutiny oil and gas development will undergo in the future,
the continued application of incidental take regulations, and the low
risk of an oil spill. Commercial fishing is also currently not a threat
to walrus, as it occurs only on the periphery of the walrus' range and
results in minimal impacts on the population. We recognize the
potential future interest by the fishing industry to initiate fisheries
further north as fish distribution changes in association with
predicted changes in ocean conditions. However, based on the limited
fishing-related impacts to walrus that have occurred in other areas to
date, and the active engagement of the NPFMC through the Arctic
Fisheries Management Plan, we conclude that commercial fishing is not
now, and is not likely to become, a threat to Pacific walrus in the
foreseeable future. Shipping is not currently a threat to the Pacific
walrus population, because it occurs at low levels, and shipping in
support of other activities (e.g., oil and gas exploration) is
sufficiently regulated and mitigated by MMPA incidental take
regulations. Shipping may increase in the future, but shipping lanes
are typically limited to narrow corridors, and disturbance from such
activities is expected to be low. Moreover, given the uncertainties
identified related to potential future shipping activities, we conclude
that increased shipping activities are unlikely to cause population-
level effects to the Pacific walrus in the foreseeable future. In
addition, take provisions of the MMPA can be effective in regulating
shipping in U.S. waters that may disturb haulouts and interrupt
foraging activity. Because most oil spills will have only localized
impact to walrus, and the chance of a large-scale spill occurring in
the walrus' range in the foreseeable future is considered low, oil
spills do not appear to be a threat to Pacific walrus now or in the
foreseeable future. Finally, shipping activity and associated
icebreaking is predicted to increase in the future, but the magnitude
and rate of increase are unknown and dependent on both economic and
environmental factors. Based on the best information available at this
time, we are unable to conclude that these shipping activities will be
a threat to the Pacific walrus in the foreseeable future, in light of
the uncertainties in projecting the magnitude and rate of increase of
these activities in the future.
Therefore, based on our review of the best commercial and
scientific data available, we conclude that none of the potential
stressors identified and discussed under Factor E (``Other Natural or
Manmade Factors Affecting Its Continued Existence of the Pacific
Walrus'') is a threat to the Pacific walrus
now, or is likely to become a threat in the foreseeable future.
As required by the Act, we considered each of the five factors
under section 4(a)(1)(A) in assessing whether the Pacific walrus is
endangered or threatened throughout all or a significant portion of its
range. We carefully examined the best scientific and commercial
information available regarding the past, present, and future threats
faced by the Pacific walrus. We considered the information provided in
the petition submitted to the Service by the Center for Biological
Diversity; information available in our files; other available
published and unpublished information; information submitted to the
Service in response to our Federal Register notice of September 10,
2009; and information submitted to the Service in response to our
public news release requesting information on September 10, 2010. We
also consulted with recognized Pacific walrus experts and other
Federal, State, and Tribal agencies.
In our analysis of Factor A, we identified and evaluated the risks
of present or threatened destruction, modification, or curtailment of
habitat or range of the Pacific walrus from (1) loss of sea ice due to
climate change and (2) effects on prey species due to ocean warming and
ocean acidification. We examined the likely responses and effects of
changing sea-ice conditions in the Bering and Chukchi Seas on Pacific
walruses. Pacific walrus is an ice-dependent species. Individuals use
ice for many aspects of their life history throughout the year, and
because of the projected loss of sea ice over the 21st century, we have
identified the loss of sea ice and associated effects to be a threat to
the Pacific walrus population. Although we anticipate that sufficient
ice will remain, so that breeding behavior and calving will still occur
in association with sea ice, the locations of these activities will
likely change in response to changing ice patterns. The greatest change
in sea ice, walrus distribution, and behavioral responses is expected
to occur in the summer (June-August) and fall (October and November),
when sea-ice loss is projected to be the greatest.
Based on the best scientific information available, in the
foreseeable future, we anticipate that there will be a 1-5-month period
in which sea ice will typically retreat northward off of the Chukchi
continental shelf. The Chukchi Sea is projected to be ice-free in
September every year by mid-century. However, loss of sea ice is
occurring faster than forecast and, on average, sea ice has retreated
off the continental shelf for approximately 1 month per year during the
last decade. At mid-century, model subsets project a 2-month ice-free
season in the Chukchi Sea, and a 4-month ice-free season at the end of
the century, centered on the month of September (Douglas 2010, p. 8),
with some models indicating there will be 5 ice-free months. Based on
the current rate of sea-ice loss, and the current rate of GHG
increases, these changes may occur earlier in the century than
Through our analysis, we have concluded that loss of sea ice, with
its concomitant changes to walrus distribution and life-history
patterns, will lead to a population decline, and is a threat to Pacific
walrus in the foreseeable future. We base this conclusion on the fact
that, over time, walruses will be forced to rely on terrestrial
haulouts to an increasingly greater extent. Although coastal haulouts
have been traditionally used more frequently by males than by females
with calves, in the future both sexes and all ages will be restricted
to coastal habitats for a much greater period of time. This will expose
all individuals, but especially calves, juveniles, and females, to
increased levels of stress from depletion of prey, increased energetic
costs to obtain prey, trampling injuries and mortalities, and
predation. Although some of these stressors are currently acting on the
population, we anticipate that their magnitude will increase over time
as sea-ice loss over the continental shelf occurs regularly and more
extensively. Given this persistent and increasing threat of sea-ice
loss, we conclude that this anticipated Pacific walrus population
decline will continue into the foreseeable future.
Under Factor A, we also analyzed the effects of ocean warming and
ocean acidification on Pacific walrus. Although we are concerned about
the changes to the walrus prey base that may occur from ocean
acidification and warming, and theoretically we understand how those
stressors might operate, ocean dynamics are very complex and the
specific outcomes for these stressors are too unreliable at this time
for us to conclude that they are a threat to Pacific walrus now or in
the foreseeable future. We therefore conclude that these stressors do
not rise to the level of a threat, now or in the foreseeable future.
In our analysis of Factor B, we identified and evaluated the risks
to Pacific walrus from overutilization for commercial, recreational,
scientific, or educational purposes. Under Factor B, we considered four
potential risks to the Pacific walrus from overutilization relating to
(1) Recreation, scientific, or educational purposes; (2) United States
import/export; (3) commercial harvest; and (4) subsistence harvest. We
found that recreational, scientific, and educational utilization of
walruses is currently at low levels and is not projected to be a threat
in the foreseeable future. United States import/export is not
considered to be a threat to Pacific walrus now or in the foreseeable
future, because most specimens imported into or exported from the
United States are fossilized bone and ivory shards, and any other
walrus ivory can only be imported into or exported from the United
States after it has been legally harvested and substantially altered to
qualify as a Native handicraft. Commercial and sport hunting of Pacific
walrus in the United States is prohibited under the MMPA. Russian
legislation also prohibits sport hunting of Pacific walruses.
Commercial hunting in Russia has not occurred since 1991, and
resumption would require the issuance of a governmental decree. In
addition, any future commercial harvest in Russia must be based on a
sustainable quota; therefore, it is unlikely that any potential future
Russian commercial harvest will become a threat to the Pacific walrus
With regard to the subsistence harvest of walrus, subsistence
harvest in Chukotka, Russia, is controlled through a quota system. An
annual subsistence quota is issued through a decree by the Russian
Federal Fisheries Agency. Quota recommendations are based on what is
thought to be a sustainable removal level (approximately 4 percent of
the population), based on the total population and productivity
estimates. However, there are no U.S. quotas on subsistence harvest.
Although at present it is difficult to quantify sustainable removal
levels because of the lack of information on Pacific walrus population
status and trends, we determined that 4 percent is a conservative
sustainable harvest level. The current level of subsistence harvest
rangewide is about 4 percent of the 2006 population estimate.
Therefore, we do not consider the current level of subsistence harvest
to be a threat to Pacific walrus at the present time.
Pacific walrus are an important subsistence resource in the Bering
Strait region, and we expect Pacific walrus to continue to remain
available for harvest there, even as sea-ice conditions change. Because
there are no U.S. subsistence harvest quotas, we do not expect harvest
levels in the Bering Strait region to change appreciably in the
foreseeable future, unless regulations are put in place to restrict
harvest by limiting the number of walrus that may be taken. There are
two paths that could result in harvest quotas: (1) Self-regulation
activities by Alaska Natives; and (2) implementation of procedures in
the MMPA. Neither of these is currently in place, except for one quota
on Round Island, as discussed below. Instead, we predict that
subsistence harvest is likely to continue at similar levels to those
currently, even as the walrus population declines in response to loss
of summer sea ice. Over time, as the proportion of animals harvested
increases relative to the overall population, this continued level of
subsistence harvest likely will become unsustainable. Therefore, we
determine that subsistence harvest is a threat to the walrus population
in the foreseeable future.
In our analysis of Factor C, we identified and evaluated the risks
to Pacific walrus from disease and predation, and we determined that
neither component currently, or in the foreseeable future, represents
threats to the Pacific walrus population. Although a changing climate
may increase exposure of walrus to new pathogens, there are no clear
transmission vectors that would change levels of exposure, and no
evidence exists that disease will become a threat in foreseeable
As the use of coastal haulouts by both walruses and polar bears
during summer increases, we expect interactions between the two species
to also increase, and terrestrial walrus haulouts may become important
feeding areas for polar bears. The presence of polar bears along the
coast during the ice-free season will likely influence patterns of
haulout use as walrus shift to other coastal haulout locations. These
movements may result in increased energetic costs to walrus, but it is
not possible to predict the magnitude of these costs. Although
predation by polar bears on Pacific walrus has been observed, the lack
of documented population-level effects leads us to conclude that polar
bear predation is not currently a threat to the Pacific walrus. As sea
ice declines and Pacific walrus spend more time on coastal haulouts,
however, it is likely that polar bear predation will increase. However,
we cannot reliably predict the level of predation in the future, and
therefore we are not able to conclude with sufficient reliability that
it will rise to the level of a threat to the Pacific walrus population
in the foreseeable future. There is no evidence that killer whale
predation has ever limited the Pacific walrus population, and there is
no evidence of increased presence of killer whales in the Bering or
Chukchi Seas; therefore, killer whale predation is not a threat to the
Pacific walrus now, and it is unlikely to become a threat in the
In our analysis under Factor D, we identified and evaluated the
risks from the inadequacy of existing regulatory mechanisms by focusing
our analysis on the specific laws and regulations aimed at addressing
the two primary threats to the walrus--the loss of sea-ice habitat and
subsistence harvest. As discussed previously under Factor A, GHG
emissions have contributed to a warming climate and the loss of sea-ice
habitat for the Pacific walrus. There are currently no regulatory
mechanisms in place to reduce or limit GHG emissions. This situation
was considered as part of our analysis in Factor A. Accordingly, there
are no existing regulatory mechanisms to effectively address sea-ice
With regard to the other main threat to the walrus, subsistence
harvest, there is currently no limit on the number of walrus that may
be taken for subsistence purposes rangewide. While the subsistence
harvest in Russia is controlled through a quota system, no national or
Statewide quota exists in the United States. One local quota restricts
the number of walrus that may be taken on Round Island (Alaska), but
the harvest level in this area represents only a very minor portion of
the harvest rangewide. Local ordinances recently adopted by two Native
communities in the Bering Strait region, where 84 percent of the
harvest in the United States and 43 percent of the rangewide harvest
occurs, contain provisions aimed at restricting the number of hunting
trips that may be taken for subsistence purposes. While these
ordinances provide an important framework for future co-management
initiatives and the potential development of future localized harvest
limits, we acknowledge that no limits currently exist on the total
number of walrus that may be taken in the Bering Strait region or
rangewide. Nor are there other restrictions in place to ensure the
likelihood that, as the population of walrus declines in response to
changing sea-ice conditions, the subsistence harvest of walrus will
occur at a reduced level. As a result, we determine that the existing
regulatory mechanisms are inadequate to address the threat of
subsistence harvest to the Pacific walrus in the foreseeable future.
In our analysis under Factor E, we evaluated other factors that may
have an effect on the Pacific walrus, including pollution and
contaminants; oil and gas exploration, development, and production;
commercial fisheries interactions; shipping; oil spills; and
icebreaking activities. Based on our estimation of low current
contaminant loads and the likelihood of minimal future exposure as
walruses feed on lower trophic levels, we conclude that contaminants
are not a threat now and are not likely to be a threat to the Pacific
walrus population in the foreseeable future. Oil and gas development is
currently not a threat to the Pacific walrus and is not expected to be
in the foreseeable future due to the anticipated increased scrutiny oil
and gas development will undergo in the future, the continued
application of incidental take regulations, and the low risk of an oil
spill. Commercial fishing is also currently not a threat to walrus as
it occurs only on the periphery of the species' range and results in
minimal impacts on the population. We recognize the potential future
interest by the fishing industry to initiate fisheries further north as
fish distribution changes in association with predicted changes in
ocean conditions. However, based on the limited fishing-related impacts
to walrus that have occurred in other areas to date, and the active
engagement of the NPFMC through the Arctic Fisheries Management Plan,
we conclude that commercial fishing is not now a threat to Pacific
walrus, and is not likely to become a threat in the foreseeable future.
Shipping is not currently a threat to the Pacific walrus population,
because it occurs at low levels, and shipping in support of other
activities (e.g., oil and gas exploration) is sufficiently regulated
and mitigated by MMPA incidental take regulations. Shipping may
increase in the future, but given the uncertainties identified related
to potential future shipping activities, the available information does
not allow us to conclude that these activities will cause population-
level effects to the Pacific walrus in the foreseeable future. In
addition, take provisions of the MMPA can be effective in regulating
shipping in U.S. waters that may disturb haulouts and interrupt
foraging activity. Because most oil spills will have only localized
impact to walrus, and the chance of a large-scale spill occurring in
the walrus' range in the foreseeable future is considered low, oil
spills do not appear to be a threat to Pacific walrus now or in the
foreseeable future. Finally, shipping activity and associated
icebreaking are predicted to increase in the future, but the magnitude
and rate of increase are unknown and dependent on both
economic and environmental factors. Given the uncertainties identified
related to potential future shipping activities, the available
information does not enable us to conclude that icebreaking will cause
population-level effects to the Pacific walrus in the foreseeable
future. Therefore, we determine that none of the potential stressors
identified and discussed under Factor E is a threat to the Pacific
walrus now, or is likely to become a threat in the foreseeable future.
In summary, we identify loss of sea ice in the summer and fall and
associated impacts (Factor A) and subsistence harvest (Factor B) as the
primary threats to the Pacific walrus in the foreseeable future. These
conclusions are supported by the Bayesian Network models prepared by
USGS and the Service. Our Factor D analysis determined that existing
regulatory mechanisms are currently inadequate to address these
threats. These threats are of sufficient imminence, intensity, and
magnitude to cause substantial losses of abundance and an anticipated
population decline of Pacific walrus that will continue into the
Therefore, on the basis of the best scientific and commercial
information available, we find that the petitioned action to list the
Pacific walrus is warranted. We will make a determination on the status
of the species as threatened or endangered when we prepare a proposed
listing determination. However, as explained in more detail below, an
immediate proposal of a regulation implementing this action is
precluded by higher priority listing actions, and expeditious progress
is being made to add or remove qualified species from the Lists of
Endangered and Threatened Wildlife and Plants.
We reviewed the available information to determine if the existing
and foreseeable threats render the species at risk of extinction at
this time such that issuing an emergency regulation temporarily listing
the species under section 4(b)(7) of the Act is warranted. We
determined that issuing an emergency regulation temporarily listing the
species is not warranted for this species at this time, because the
threats acting on the species are not immediately impacting the entire
species across its range to the point where the species will be
immediately lost. However, if at any time we determine that issuing an
emergency regulation temporarily listing the Pacific walrus is
warranted, we will initiate this action at that time.
Listing Priority Number
The Service adopted guidelines on September 21, 1983 (48 FR 43098),
to establish a rational system for utilizing available resources for
the highest priority species when adding species to the Lists of
Endangered and Threatened Wildlife and Plants or reclassifying species
listed as threatened to endangered status. These guidelines, titled
``Endangered and Threatened Species Listing and Recovery Priority
Guidelines,'' address the immediacy and magnitude of threats, and the
level of taxonomic distinctiveness. The system places greatest
importance on the immediacy and magnitude of threats, but also factors
in the level of taxonomic distinctiveness by assigning priority in
descending order to monotypic genera (genus with one species), full
species, and subspecies (or equivalently, distinct population segments
As a result of our analysis of the best available scientific and
commercial information, we assigned the Pacific walrus a Listing
Priority Number (LPN) of 9, based on the moderate magnitude and
imminence of threats. These threats include the present or threatened
destruction, modification or curtailment of Pacific walrus habitat due
to loss of sea-ice habitat; and overutilization due to subsistence
harvest. In addition, existing regulatory mechanisms fail to address
these threats. These threats affect the entire population, are ongoing,
and will continue to occur into the foreseeable future. Our rationale
for assigning the Pacific walrus an LPN of 9 is outlined below.
Under the Service's Guidelines, the magnitude of threat is the
first criterion we look at when establishing a listing priority. The
guidelines indicate that species with the highest magnitude of threat
are those species facing the most severe threats to their continued
existence. These species receive the highest listing priority. As
discussed in the finding, the Pacific walrus is being impacted by two
primary threats; the loss of sea-ice habitat, and subsistence harvest.
The main threat to the Pacific walrus is the loss of sea-ice habitat
due to climate change. Sea-ice losses have been observed to date and
are projected to continue through the end of the 21st century. The loss
of sea-ice habitat, while affecting individual walrus or localized
populations, does not appear to be currently resulting in significant
population-level effects. However, the modeled projections of the loss
of sea-ice habitat and the associated impacts on the Pacific walrus are
expected to greatly increase within the foreseeable future, thereby
resulting in significant population-level effects. Because the threat
of the loss of sea-ice habitat is not having significant effects
currently, but is projected to, we have determined the magnitude of
this threat is moderate, and not high.
Subsistence harvest is also identified as a threat to the Pacific
walrus. Harvest is currently occurring at sustainable levels. With the
loss of sea-ice habitat and the projected associated population
decline, and because subsistence harvest is expected to continue at
current levels, we concluded that subsistence harvest would have a
population-level effect on the species in the future. Because harvest
is occurring at sustainable levels now, but may become unsustainable in
the foreseeable future due to the projected population decline, we have
determined the magnitude of the threat of subsistence harvest is
considered to be moderate, and not high.
Under our Guidelines, the second criterion we consider in assigning
a listing priority is the immediacy of threats. This criterion is
intended to ensure that species that face actual, identifiable threats
are given priority over those species for which threats are only
potential or species that are intrinsically vulnerable but are not
known to be presently facing such threats. We have determined that loss
of sea-ice habitat is affecting the Pacific walrus population currently
and is expected to continue and likely intensify in the foreseeable
future. Similarly, we have determined that subsistence harvest is
presently occurring and expected to continue at current levels into the
foreseeable future, even as the Pacific walrus population declines due
to sea-ice loss. Because both the loss of sea-ice habitat and
subsistence harvest are presently occurring, we consider the threats to
The third criterion in our guidelines is intended to devote
resources to those species representing highly distinctive or isolated
gene pools as reflected by taxonomy, with the highest priority given to
monotypic genera, followed by species and then subspecies. The Pacific
walrus is a valid subspecies and therefore receives a lower priority
than species or a monotypic genus. As discussed, the threats affecting
the Pacific walrus are of moderate magnitude and imminent. Accordingly
we have assigned the Pacific walrus an LPN of 9, pursuant to our
We will continue to monitor the threats to the Pacific walrus, as
well as the species' status, on an annual basis, and should the
magnitude or the
imminence of the threats change, we will revisit our assessment of the
Preclusion and Expeditious Progress
Preclusion is a function of the listing priority of a species in
relation to the resources that are available and the cost and relative
priority of competing demands for those resources. Thus, in any given
fiscal year (FY), multiple factors dictate whether it will be possible
to undertake work on a listing proposal regulation or whether
promulgation of such a proposal is precluded by higher-priority listing
The resources available for listing actions are determined through
the annual Congressional appropriations process. The appropriation for
the Listing Program is available to support work involving the
following listing actions: Proposed and final listing rules; 90-day and
12-month findings on petitions to add species to the Lists of
Endangered and Threatened Wildlife and Plants (Lists) or to change the
status of a species from threatened to endangered; annual
``resubmitted'' petition findings on prior warranted-but-precluded
petition findings as required under section 4(b)(3)(C)(i) of the Act;
critical habitat petition findings; proposed and final rules
designating critical habitat; and litigation-related, administrative,
and program-management functions (including preparing and allocating
budgets, responding to Congressional and public inquiries, and
conducting public outreach regarding listing and critical habitat). The
work involved in preparing various listing documents can be extensive
and may include, but is not limited to: Gathering and assessing the
best scientific and commercial data available and conducting analyses
used as the basis for our decisions; writing and publishing documents;
and obtaining, reviewing, and evaluating public comments and peer
review comments on proposed rules and incorporating relevant
information into final rules. The number of listing actions that we can
undertake in a given year also is influenced by the complexity of those
listing actions; that is, more complex actions generally are more
costly. The median cost for preparing and publishing a 90-day finding
is $39,276; for a 12-month finding, $100,690; for a proposed rule with
critical habitat, $345,000; and for a final listing rule with critical
habitat, the median cost is $305,000.
We cannot spend more than is appropriated for the Listing Program
without violating the Anti-Deficiency Act (see 31 U.S.C.
1341(a)(1)(A)). In addition, in FY 1998 and for each fiscal year since
then, Congress has placed a statutory cap on funds which may be
expended for the Listing Program, equal to the amount expressly
appropriated for that purpose in that fiscal year. This cap was
designed to prevent funds appropriated for other functions under the
Act (for example, recovery funds for removing species from the Lists),
or for other Service programs, from being used for Listing Program
actions (see House Report 105-163, 105th Congress, 1st Session, July 1,
Since FY 2002, the Service's budget has included a critical habitat
subcap to ensure that some funds are available for other work in the
Listing Program (``The critical habitat designation subcap will ensure
that some funding is available to address other listing activities''
(House Report No. 107-103, 107th Congress, 1st Session, June 19,
2001)). From FY 2002 to FY 2006, the Service has had to use virtually
the entire critical habitat subcap to address court-mandated
designations of critical habitat, and consequently none of the critical
habitat subcap funds have been available for other listing activities.
In some FYs since 2006, we have been able to use some of the critical
habitat subcap funds for proposed listing determinations for high-
priority candidate species. In other FYs, while we were unable to use
any of the critical habitat subcap funds to fund proposed listing
determinations, we did use some of this money to fund the critical
habitat portion of some proposed listing determinations so that the
proposed listing determination and proposed critical habitat
designation could be combined into one rule, thereby being more
efficient in our work. At this time, for FY 2011, we do not know if we
will be able to use some of the critical habitat subcap funds to fund
proposed listing determinations.
We make our determinations of preclusion on a nationwide basis to
ensure that the species most in need of listing will be addressed first
and also because we allocate our listing budget on a nationwide basis.
Through the listing cap, the critical habitat subcap, and the amount of
funds needed to address court-mandated critical habitat designations,
Congress and the courts have, in effect, determined the amount of money
available for other listing activities nationwide (i.e., actions other
than critical habitat designation). Therefore, the funds in the listing
cap, other than those needed to address court-mandated critical habitat
for already listed species, set the limits on our determinations of
preclusion and expeditious progress.
Congress identified the availability of resources as the only basis
for deferring the initiation of a rulemaking that is warranted. The
Conference Report accompanying Pub. L. 97-304 (Endangered Species Act
Amendments of 1982), which established the current statutory deadlines
and the warranted-but-precluded finding, states that the amendments
were ``not intended to allow the Secretary to delay commencing the
rulemaking process for any reason other than that the existence of
pending or imminent proposals to list species subject to a greater
degree of threat would make allocation of resources to such a petition
[that is, for a lower-ranking species] unwise.'' Although that
statement appeared to refer specifically to the ``to the maximum extent
practicable'' limitation on the 90-day deadline for making a
``substantial information'' finding, that finding is made at the point
when the Service is deciding whether or not to commence a status review
that will determine the degree of threats facing the species, and
therefore the analysis underlying the statement is more relevant to the
use of the warranted-but-precluded finding, which is made when the
Service has already determined the degree of threats facing the species
and is deciding whether or not to commence a rulemaking.
In FY 2011, on December 22, 2010, Congress passed a continuing
resolution which provides funding at the FY 2010 enacted level through
March 4, 2011. Until Congress appropriates funds for FY 2011 at a
different level, we will fund listing work based on the FY 2010 amount.
Thus, at this time in FY 2011, the Service anticipates an appropriation
of $22,103,000 based on FY 2010 appropriations. Of that, the Service
anticipates needing to dedicate $11,632,000 for determinations of
critical habitat for already listed species. Also $500,000 is
appropriated for foreign species listings under the Act. The Service
thus has $9,971,000 available to fund work in the following categories:
compliance with court orders and court-approved settlement agreements
requiring that petition findings or listing determinations be completed
by a specific date; section 4 (of the Act) listing actions with
absolute statutory deadlines; essential litigation-related,
administrative, and listing program-management functions; and high-
priority listing actions for some of our candidate species. In FY 2010
the Service received many new petitions and a single petition to list
404 species. The receipt of petitions for a large number of species is
Service's listing funding that is not dedicated to meeting Court-
ordered commitments. Absent some ability to balance effort among
listing duties under existing funding levels, it is unlikely that the
Service will be able to make expeditious progress on candidate species
in FY 2011.
In 2009, the responsibility for listing foreign species under the
Act was transferred from the Division of Scientific Authority,
International Affairs Program, to the Endangered Species Program.
Therefore, starting in FY 2010, we used a portion of our funding to
work on the actions described above for listing actions related to
foreign species. In FY 2011, we anticipate using $1,500,000 for work on
listing actions for foreign species which reduces funding available for
domestic listing actions, however, currently only $500,000 has been
allocated. Although there are currently no foreign species issues
included in our high-priority listing actions at this time, many
actions have statutory or court-approved settlement deadlines, thus
increasing their priority. The budget allocations for each specific
listing action are identified in the Service's FY 2011 Allocation Table
(part of our record).
For the above reasons, funding a proposed listing determination for
the Pacific walrus is precluded by court-ordered and court-approved
settlement agreements, listing actions with absolute statutory
deadlines, and work on proposed listing determinations for those
candidate species with a higher listing priority (i.e., candidate
species with LPNs of 1-8).
Based on our September 21, 1983, guidance for assigning an LPN for
each candidate species (48 FR 43098), we have a significant number of
species with an LPN of 2. Using this guidance, we assign each candidate
an LPN of 1 to 12, depending on the magnitude of threats (high or
moderate to low), immediacy of threats (imminent or nonimminent), and
taxonomic status of the species (in order of priority: monotypic genus
(a species that is the sole member of a genus); species, or part of a
species (subspecies, distinct population segment, or significant
portion of the range)). The lower the listing priority number, the
higher the listing priority (that is, a species with an LPN of 1 would
have the highest listing priority).
Because of the large number of high-priority species, we have
further ranked the candidate species with an LPN of 2 by using the
following extinction-risk type criteria: International Union for the
Conservation of Nature and Natural Resources (IUCN) Red list status/
rank, Heritage rank (provided by NatureServe), Heritage threat rank
(provided by NatureServe), and species currently with fewer than 50
individuals, or 4 or fewer populations. Those species with the highest
IUCN rank (critically endangered), the highest Heritage rank (G1), the
highest Heritage threat rank (substantial, imminent threats), and
currently with fewer than 50 individuals, or fewer than 4 populations,
originally comprised a group of approximately 40 candidate species
(``Top 40''). These 40 candidate species have had the highest priority
to receive funding to work on a proposed listing determination. As we
work on proposed and final listing rules for those 40 candidates, we
apply the ranking criteria to the next group of candidates with an LPN
of 2 and 3 to determine the next set of highest-priority candidate
species. Finally, proposed rules for reclassification of threatened
species to endangered are lower priority, since as listed species, they
are already afforded the protection of the Act and implementing
regulations. However, for efficiency reasons, we may choose to work on
a proposed rule to reclassify a species to endangered if we can combine
this with work that is subject to a court-determined deadline.
With our workload so much bigger than the amount of funds we have
to accomplish it, it is important that we be as efficient as possible
in our listing process. Therefore, as we work on proposed rules for the
highest priority species in the next several years, we are preparing
multi-species proposals when appropriate, and these may include species
with lower priority if they overlap geographically or have the same
threats as a species with an LPN of 2. In addition, we take into
consideration the availability of staff resources when we determine
which high-priority species will receive funding to minimize the amount
of time and resources required to complete each listing action.
As explained above, a determination that listing is warranted but
precluded must also demonstrate that expeditious progress is being made
to add and remove qualified species to and from the Lists of Endangered
and Threatened Wildlife and Plants. As with our ``precluded'' finding,
the evaluation of whether progress in adding qualified species to the
Lists has been expeditious is a function of the resources available for
listing and the competing demands for those funds. (Although we do not
discuss it in detail here, we are also making expeditious progress in
removing species from the list under the Recovery program in light of
the resource available for delisting, which is funded by a separate
line item in the budget of the Endangered Species Program. So far
during FY 2011, we have completed one delisting rule.) Given the
limited resources available for listing, we find that we are making
expeditious progress in FY 2011 in the Listing program. This progress
included preparing and publishing the following determinations:
FY 2011 Completed Listing Actions
Publication date Title Actions FR pages
10/6/2010..................... Endangered Status for the Proposed Listing 75 FR 61664-61690
Altamaha Spinymussel and Endangered.
Designation of Critical Habitat.
10/7/2010..................... 12-month Finding on a Petition Notice of 12-month 75 FR 62070-62095
to list the Sacramento petition finding,
Splittail as Endangered or Not warranted.
10/28/2010.................... Endangered Status and Proposed Listing 75 FR 66481-66552
Designation of Critical Habitat Endangered
for Spikedace and Loach Minnow. (uplisting).
11/2/2010..................... 90-Day Finding on a Petition to Notice of 90-day 75 FR 67341-67343
List the Bay Springs Salamander Petition Finding,
as Endangered. Not substantial.
11/2/2010..................... Determination of Endangered Final Listing 75 FR 67511-67550
Status for the Georgia Pigtoe Endangered.
Mussel, Interrupted Rocksnail,
and Rough Hornsnail and
Designation of Critical Habitat.
11/2/2010..................... Listing the Rayed Bean and Proposed Listing 75 FR 67551-67583
Snuffbox as Endangered. Endangered.
11/4/2010..................... 12-Month Finding on a Petition Notice of 12-month 75 FR 67925-67944
to List Cirsium wrightii petition finding,
(Wright's Marsh Thistle) as Warranted but
Endangered or Threatened. precluded.
12/14/2010.................... Endangered Status for Dunes Proposed Listing 75 FR 77801-77817
Sagebrush Lizard. Endangered.
12/14/2010.................... 12-month Finding on a Petition Notice of 12-month 75 FR 78029-78061
to List the North American petition finding,
Wolverine as Endangered or Warranted but
12/14/2010.................... 12-Month Finding on a Petition Notice of 12-month 75 FR 78093-78146
to List the Sonoran Population petition finding,
of the Desert Tortoise as Warranted but
Endangered or Threatened. precluded.
12/15/2010.................... 12-Month Finding on a Petition Notice of 12-month 75 FR 78513-78556
to List Astragalus microcymbus petition finding,
and Astragalus schmolliae as Warranted but
Endangered or Threatened. precluded.
12/28/2010.................... Listing Seven Brazilian Bird Final Listing 75 FR 81793-81815
Species as Endangered Endangered.
Throughout Their Range.
1/4/2011...................... 90[dash]Day Finding on a Notice of 90-day 76 FR 304-311
Petition to List the Red Knot Petition Finding,
subspecies Calidris canutus Not substantial.
roselaari as Endangered.
1/19/2011..................... Endangered Status for the Proposed Listing 76 FR 3392-3420
Sheepnose and Spectaclecase Endangered.
Our expeditious progress also includes work on listing actions that
we funded in FY 2010 and FY 2011, but have not yet been completed to
date. These actions are listed below. Actions in the top section of the
table are being conducted under a deadline set by a court. Actions in
the middle section of the table are being conducted to meet statutory
timelines, that is, timelines required under the Act. Actions in the
bottom section of the table are high-priority listing actions. These
actions include work primarily on species with an LPN of 2, and, as
discussed above, selection of these species is partially based on
available staff resources, and when appropriate, include species with a
lower priority if they overlap geographically or have the same threats
as the species with the high priority. Including these species together
in the same proposed rule results in considerable savings in time and
funding compared to preparing separate proposed rules for each of them
in the future.
Actions Funded in FY 2010 and FY 2011 but Not Yet Completed
Actions Subject to Court Order/Settlement Agreement
Flat-tailed horned lizard.................. Final listing
Mountain plover\4\......................... Final listing
Solanum conocarpum......................... 12-month petition finding.
Thorne's Hairstreak butterfly\3\........... 12-month petition finding.
Hermes copper butterfly\3\................. 12-month petition finding.
4 parrot species (military macaw, yellow- 12-month petition finding.
billed parrot, red-crowned parrot, scarlet
4 parrot species (blue-headed macaw, great 12-month petition finding.
green macaw, grey-cheeked parakeet,
4 parrot species (crimson shining parrot, 12-month petition finding.
white cockatoo, Philippine cockatoo,
Utah prairie dog (uplisting)............... 90-day petition finding.
Actions With Statutory Deadlines
Casey's june beetle........................ Final listing
Southern rockhopper penguin--Campbell Final listing
Plateau population. determination.
6 Birds from Eurasia....................... Final listing
5 Bird species from Colombia and Ecuador... Final listing
Queen Charlotte goshawk.................... Final listing
5 species southeast fish (Cumberland Final listing
darter, rush darter, yellowcheek darter, determination.
chucky madtom, and laurel dace)\4\.
Ozark hellbender\4\........................ Final listing
Altamaha spinymussel\3\.................... Final listing
3 Colorado plants (Ipomopsis polyantha Final listing
(Pagosa Skyrocket), Penstemon debilis determination.
(Parachute Beardtongue), and Phacelia
submutica (DeBeque Phacelia))\4\.
Salmon crested cockatoo.................... Final listing
6 Birds from Peru & Bolivia................ Final listing
Loggerhead sea turtle (assist National Final listing
Marine Fisheries Service)\5\. determination.
2 mussels (rayed bean (LPN = 2), snuffbox Final listing
No LPN)\5\. determination.
Mt Charleston blue\5\...................... Proposed listing
CA golden trout\4\......................... 12-month petition finding.
Black-footed albatross..................... 12-month petition finding.
Mount Charleston blue butterfly............ 12-month petition finding.
Mojave fringe-toed lizard\1\............... 12-month petition finding.
Kokanee--Lake Sammamish population\1\...... 12-month petition finding.
Cactus ferruginous pygmy-owl\1\............ 12-month petition finding.
Northern leopard frog...................... 12-month petition finding.
Tehachapi slender salamander............... 12-month petition finding.
Coqui Llanero.............................. 12-month petition finding/
Dusky tree vole............................ 12-month petition finding.
3 MT invertebrates (mist forestfly (Lednia 12-month petition finding.
tumana), Oreohelix sp. 3, Oreohelix sp.
31) from 206 species petition.
5 UT plants (Astragalus hamiltonii, 12-month petition finding.
Eriogonum soredium, Lepidium ostleri,
Penstemon flowersii, Trifolium friscanum)
from 206 species petition.
5 WY plants (Abronia ammophila, Agrostis 12-month petition finding.
rossiae, Astragalus proimanthus, Boechere
(Arabis) pusilla, Penstemon gibbensii)
from 206 species petition.
Leatherside chub (from 206 species 12-month petition finding.
Frigid ambersnail (from 206 species 12-month petition finding.
Platte River caddisfly (from 206 species 12-month petition finding.
Gopher tortoise--eastern population........ 12-month petition finding.
Grand Canyon scorpion (from 475 species 12-month petition finding.
Anacroneuria wipukupa (a stonefly from 475 12-month petition finding.
Rattlesnake-master borer moth (from 475 12-month petition finding.
3 Texas moths (Ursia furtiva, Sphingicampa 12-month petition finding.
blanchardi, Agapema galbina) (from 475
2 Texas shiners (Cyprinella sp., Cyprinella 12-month petition finding.
lepida) (from 475 species petition).
3 South Arizona plants (Erigeron 12-month petition finding.
piscaticus, Astragalus hypoxylus,
Amoreuxia gonzalezii) (from 475 species
5 Central Texas mussel species (3 from 475 12-month petition finding.
14 parrots (foreign species)............... 12-month petition finding.
Berry Cave salamander\1\................... 12-month petition finding.
Striped Newt\1\............................ 12-month petition finding.
Fisher--Northern Rocky Mountain Range\1\... 12-month petition finding.
Mohave Ground Squirrel\1\.................. 12-month petition finding.
Puerto Rico Harlequin Butterfly\3\......... 12-month petition finding.
Western gull-billed tern................... 12-month petition finding.
Ozark chinquapin (Castanea pumila var. 12-month petition finding.
HI yellow-faced bees....................... 12-month petition finding.
Giant Palouse earthworm.................... 12-month petition finding.
Whitebark pine............................. 12-month petition finding.
OK grass pink (Calopogon oklahomensis)\1\.. 12-month petition finding.
Ashy storm-petrel\5\....................... 12-month petition finding.
Honduran emerald........................... 12-month petition finding.
Southeastern pop snowy plover & wintering 90-day petition finding.
pop. of piping plover\1\.
Eagle Lake trout\1\........................ 90-day petition finding.
Smooth-billed ani\1\....................... 90-day petition finding.
32 Pacific Northwest mollusks species 90-day petition finding.
(snails and slugs)\1\.
42 snail species (Nevada & Utah)........... 90-day petition finding.
Peary caribou.............................. 90-day petition finding.
Plains bison............................... 90-day petition finding.
Spring Mountains checkerspot butterfly..... 90-day petition finding.
Spring pygmy sunfish....................... 90-day petition finding.
Bay skipper................................ 90-day petition finding.
Unsilvered fritillary...................... 90-day petition finding.
Texas kangaroo rat......................... 90-day petition finding.
Spot-tailed earless lizard................. 90-day petition finding.
Eastern small-footed bat................... 90-day petition finding.
Northern long-eared bat.................... 90-day petition finding.
Prairie chub............................... 90-day petition finding.
10 species of Great Basin butterfly........ 90-day petition finding.
6 sand dune (scarab) beetles............... 90-day petition finding.
Golden-winged warbler\4\................... 90-day petition finding.
Sand-verbena moth.......................... 90-day petition finding.
404 Southeast species...................... 90-day petition finding.
Franklin's bumble bee\4\................... 90-day petition finding.
2 Idaho snowflies (straight snowfly & Idaho 90-day petition finding.
American eel\4\............................ 90-day petition finding.
Gila monster (Utah population)\4\.......... 90-day petition finding.
Arapahoe snowfly\4\........................ 90-day petition finding.
Leona's little blue\4\..................... 90-day petition finding.
Aztec gilia\5\............................. 90-day petition finding.
White-tailed ptarmigan\5\.................. 90-day petition finding.
San Bernardino flying squirrel\5\.......... 90-day petition finding.
Bicknell's thrush\5\....................... 90-day petition finding.
Chimpanzee................................. 90-day petition finding.
Sonoran talussnail\5\...................... 90-day petition finding.
2 AZ Sky Island plants (Graptopetalum 90-day petition finding.
bartrami & Pectis imberbis)\5\.
I'iwi\5\................................... 90-day petition finding.
High-Priority Listing Actions
19 Oahu candidate species\2\ (16 plants, 3 Proposed listing.
damselflies) (15 with LPN = 2, 3 with LPN
= 3, 1 with LPN = 9).
19 Maui-Nui candidate species\2\ (16 Proposed listing.
plants, 3 tree snails) (14 with LPN = 2, 2
with LPN = 3, 3 with LPN = 8).
2 Arizona springsnails\2\ (Pyrgulopsis Proposed listing.
bernadina (LPN = 2), Pyrgulopsis trivialis
(LPN = 2)).
Chupadera springsnail\2\ (Pyrgulopsis Proposed listing.
chupaderae (LPN = 2).
8 Gulf Coast mussels (southern kidneyshell Proposed listing.
(LPN = 2), round ebonyshell (LPN = 2),
Alabama pearlshell (LPN = 2), southern
sandshell (LPN = 5), fuzzy pigtoe (LPN =
5), Choctaw bean (LPN = 5), narrow pigtoe
(LPN = 5), and tapered pigtoe (LPN =
Umtanum buckwheat (LPN = 2) and white Proposed listing.
bluffs bladderpod (LPN = 9)\4\.
Grotto sculpin (LPN = 2)\4\................ Proposed listing.
2 Arkansas mussels (Neosho mucket (LPN = 2) Proposed listing.
& Rabbitsfoot (LPN = 9))\4\.
Diamond darter (LPN = 2)\4\................ Proposed listing.
Gunnison sage-grouse (LPN = 2)\4\.......... Proposed listing.
Miami blue (LPN = 3)\3\.................... Proposed listing.
4 Texas salamanders (Austin blind Proposed listing.
salamander (LPN = 2), Salado salamander
(LPN = 2), Georgetown salamander (LPN =
8), Jollyville Plateau (LPN = 8))\3\.
5 SW aquatics (Gonzales Spring Snail (LPN = Proposed listing.
2), Diamond Y springsnail (LPN = 2),
Phantom springsnail (LPN = 2), Phantom
Cave snail (LPN = 2), Diminutive amphipod
(LPN = 2))\3\.
2 Texas plants (Texas golden gladecress Proposed listing.
(Leavenworthia texana) (LPN = 2), Neches
River rose-mallow (Hibiscus dasycalyx)
(LPN = 2))\3\.
FL bonneted bat (LPN = 2)\3\............... Proposed listing.
21 Big Island (HI) species\5\ (includes 8 Proposed listing.
candidate species--5 plants & 3 animals; 4
with LPN = 2, 1 with LPN = 3, 1 with LPN =
4, 2 with LPN = 8).
12 Puget Sound prairie species (9 Proposed listing.
subspecies of pocket gopher (Thomomys
mazama ssp.) (LPN = 3), streaked horned
lark (LPN = 3), Taylor's checkerspot (LPN
= 3), Mardon skipper (LPN = 8))\3\.
2 TN River mussels (fluted kidneyshell (LPN Proposed listing.
= 2), slabside pearlymussel (LPN = 2))\5\.
Jemez Mountain salamander (LPN = 2) \5\.... Proposed listing.
\1\ Funds for listing actions for these species were provided in
\2\ Although funds for these high-priority listing actions were provided
in FY 2008 or 2009, due to the complexity of these actions and
competing priorities, these actions are still being developed.
\3\ Partially funded with FY 2010 funds and FY 2011 funds.
\4\ Funded with FY 2010 funds.
\5\ Funded with FY 2011 funds.
We have endeavored to make our listing actions as efficient and
timely as possible, given the requirements of the relevant law and
regulations and constraints relating to workload and personnel. We are
continually considering ways to streamline processes or achieve
economies of scale, such as by batching related actions together. Given
our limited budget for implementing section 4 of the Act, these actions
described above collectively constitute expeditious progress.
The Pacific walrus will be added to the list of candidate species
upon publication of this 12-month finding. We will continue to monitor
the status of this population as new information becomes available.
This review will determine if a change in status is warranted,
including the need to make prompt use of emergency-listing procedures.
We intend that any proposed listing determination for the Pacific
walrus will be as accurate as possible. Therefore, we will continue to
accept additional information and comments from all concerned
governmental agencies, the scientific community, the subsistence
community, industry, or any other interested party concerning this
A complete list of references cited is available on the Internet at
http://www.regulations.gov and upon request from the Alaska Marine
Mammals Office (see ADDRESSES section).
The primary authors of this notice are the staff members of the
Marine Mammals Management Office and the Fisheries and Ecological
Services Division of the Alaska Regional Office.
The authority for this section is section 4 of the Endangered
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).
Dated: January 21, 2011.
Rowan W. Gould,
Acting Director, Fish and Wildlife Service.
[FR Doc. 2011-2400 Filed 2-9-11; 8:45 am]
BILLING CODE 4310-55-P