Daily Rules, Proposed Rules, and Notices of the Federal Government


National Oceanic and Atmospheric Administration

50 CFR Part 223

[Docket No. 101126591-0588-01]

RIN 0648-XZ58

Endangered and Threatened Species; Proposed Threatened and Not Warranted Status for Subspecies and Distinct Population Segments of the Bearded Seal

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.
ACTION: Proposed rule; 12-month petition finding; status review; request for comments.
SUMMARY: We, NMFS, have completed a comprehensive status review of the bearded seal (Erignathus barbatus) under the Endangered Species Act (ESA) and announce a 12-month finding on a petition to list the bearded seal as a threatened or endangered species. The bearded seal exists as two subspecies:Erignathus barbatus nauticusandErignathus barbatus barbatus. Based on the findings from the status review report and consideration of the factors affecting these subspecies, we conclude thatE. b. nauticusconsists of two distinct population segments (DPSs), the Beringia DPS and the Okhotsk DPS. Moreover, based on consideration of information presented in the status review report, an assessment of the factors in section 4(a)(1) of the ESA, and efforts being made to protect the species, we have determined the Beringia DPS and the Okhotsk DPS are likely to become endangered throughout all or a significant portion of their ranges in the foreseeable future. We have also determined thatE. b. barbatusis not in danger of extinction or likely to become endangered throughout all or a significant portion of its range in the foreseeable future. Accordingly, we are now issuing a proposed rule to list the Beringia DPS and the Okhotsk DPS of the bearded seal as threatened species. No listing action is proposed forE. b. barbatus.We solicit comments on this proposed action. At this time, we do not propose to designate critical habitat for the Beringia DPS because it is not currently determinable. In order to complete the critical habitat designation process, we solicit information on the essential physical and biological features of bearded seal habitat for the Beringia DPS.
DATES: Comments and information regarding this proposed rule must be received by close of business on February 8, 2011. Requests for public hearings must be made in writing and received by January 24, 2011.
ADDRESSES: *Electronic Submissions:Submit all electronic public comments via the Federal eRulemaking Portal

*Mail:P.O. Box 21668, Juneau, AK 99802.

*Fax:(907) 586-7557.

*Hand delivery to the Federal Building:709 West 9th Street, Room 420A, Juneau, AK.

All comments received are a part of the public record. No comments will be posted tohttp://www.regulations.govfor public viewing until after the comment period has closed. Comments will generally be posted without change. All Personal Identifying Information (for example, name, address,etc.) voluntarily submitted by the commenter may be publicly accessible. Do not submit Confidential Business Information or otherwise sensitive or protected information.

We will accept anonymous comments (enter N/A in the required fields, if you wish to remain anonymous). You may submit attachments to electronic comments in Microsoft Word, Excel, WordPerfect, or Adobe PDF file formats only.

The proposed rule, maps, status review report and other materials relating to this proposal can be found on the Alaska Region Web site at:

FOR FURTHER INFORMATION CONTACT: Tamara Olson, NMFS Alaska Region, (907) 271-5006; Kaja Brix, NMFS Alaska Region, (907) 586-7235; or Marta Nammack, Office of Protected Resources, Silver Spring, MD, (301) 713-1401.

On March 28, 2008, we initiated status reviews of bearded, ringed (Phoca hispida), and spotted seals (Phoca largha) under the ESA (73 FR 16617). On May 28, 2008, we received a petition from the Center for Biological Diversity to list these three species of seals as threatened or endangered under the ESA, primarily due to concerns about threats to their habitat from climate warming and loss of sea ice. The Petitioner also requested that critical habitat be designated for these species concurrent with listing under the ESA. Section 4(b)(3)(B) of the ESA of 1973, as amended (16 U.S.C. 1531et seq.) requires that when a petition to revise the List of Endangered and Threatened Wildlife and Plants is found to present substantial scientific and commercial information, we make a finding on whether the petitioned action is (a) Not warranted, (b) warranted, or (c) warranted but precluded from immediate proposal by other pending proposals of higher priority. This finding is to be made within 1 year of the date the petition was received, and the finding is to be published promptly in theFederal Register.

After reviewing the petition, the literature cited in the petition, and other literature and information available in our files, we found (73 FR 51615; September 4, 2008) that the petition met the requirements of the regulations under 50 CFR 424.14(b)(2), and we determined that the petition presented substantial information indicating that the petitioned action may be warranted. Accordingly, we proceeded with the status reviews of bearded, ringed, and spotted seals and solicited information pertaining to them.

On September 8, 2009, the Center for Biological Diversity filed a lawsuit in the U.S. District Court for the District of Columbia alleging that we failed to make the requisite 12-month finding on its petition to list the three seal species. Subsequently, the Court entered a consent decree under which we agreed to finalize the status review of the bearded seal (and the ringed seal) and submit this 12-month finding to the Office of the Federal Register by December 3, 2010. Our 12-month petition finding for ringed seals is published as a separate notice concurrently with this finding. Spotted seals were also addressed in a separateFederal Registernotice (75 FR 65239; October 22, 2010; see also, 74 FR 53683, October 20, 2009).

The status review report of the bearded seal is a compilation of the best scientific and commercial data available concerning the status of the species, including the past, present, and future threats to this species. The Biological Review Team (BRT) that prepared this report was composed of eight marine mammal biologists, a fishery biologist, a marine chemist, and a climate scientist from NMFS' Alaska and Northeast Fisheries Science Centers, NOAA's Pacific Marine Environmental Lab, and the U.S. Fish and Wildlife Service (USFWS). The status review report underwent independent peer review by five scientists with expertise in beardedseal biology, Arctic sea ice, climate change, and ocean acidification.

ESA Statutory, Regulatory, and Policy Provisions

There are two key tasks associated with conducting an ESA status review. The first is to delineate the taxonomic group under consideration; and the second is to conduct an extinction risk assessment to determine whether the petitioned species is threatened or endangered.

To be considered for listing under the ESA, a group of organisms must constitute a “species,” which section 3(16) of the ESA defines as “any subspecies of fish or wildlife or plants, and any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature.” The term “distinct population segment” (DPS) is not commonly used in scientific discourse, so the USFWS and NMFS developed the “Policy Regarding the Recognition of Distinct Vertebrate Population Segments Under the Endangered Species Act” to provide a consistent interpretation of this term for the purposes of listing, delisting, and reclassifying vertebrates under the ESA (61 FR 4722; February 7, 1996). We describe and use this policy below to guide our determination of whether any population segments of this species meet the DPS criteria of the DPS policy.

The ESA defines the term “endangered species” as “any species which is in danger of extinction throughout all or a significant portion of its range.” The term “threatened species” is defined as “any species which is likely to become endangered within the foreseeable future throughout all or a significant portion of its range.” The foreseeability of a species' future status is case specific and depends upon both the foreseeability of threats to the species and foreseeability of the species' response to those threats. When a species is exposed to a variety of threats, each threat may be foreseeable in a different timeframe. For example, threats stemming from well-established, observed trends in a global physical process may be foreseeable on a much longer time horizon than a threat stemming from a potential, though unpredictable, episodic process such as an outbreak of disease that may never have been observed to occur in the species.

In the 2008 status review of the ribbon seal (Bovenget al.,2008; see also 73 FR 79822, December 30, 2008), NMFS scientists used the same climate projections used in our risk assessment here, but terminated the analysis of threats to ribbon seals at 2050. One reason for that approach was the difficulty of incorporating the increased divergence and uncertainty in climate scenarios beyond that time. Other reasons included the lack of data for threats other than those related to climate change beyond 2050, and the fact that the uncertainty embedded in the assessment of the ribbon seal's response to threats increased as the analysis extended farther into the future.

Since that time, NMFS scientists have revised their analytical approach to the foreseeability of threats and responses to those threats, adopting a more threat-specific approach based on the best scientific and commercial data available for each respective threat. For example, because the climate projections in the Intergovernmental Panel on Climate Change's (IPCC's)Fourth Assessment Reportextend through the end of the century (and we note the IPCC'sFifth Assessment Report,due in 2014, will extend even farther into the future), we used those models to assess impacts from climate change through the end of the century. We continue to recognize that the farther into the future the analysis extends, the greater the inherent uncertainty, and we incorporated that limitation into our assessment of the threats and the species' response. For other threats, where the best scientific and commercial data does not extend as far into the future, such as for occurrences and projections of disease or parasitic outbreaks, we limited our analysis to the extent of such data. We believe this approach creates a more robust analysis of the best scientific and commercial data available.

Species Information

A thorough review of the taxonomy, life history, and ecology of the bearded seal is presented in the status review report (Cameronet al.,2010; available at The bearded seal is the largest of the northern ice-associated seals, with typical adult body sizes of 2.1-2.4 m in length and weight up to 360 kg. Bearded seals have several distinctive physical features including a wide girth; a small head in proportion to body size; long whiskers; and square-shaped fore flippers. The life span of bearded seals is about 20-25 years.

Bearded seals have a circumpolar distribution south of 85° N. latitude, extending south into the southern Bering Sea in the Pacific and into Hudson Bay and southern Labrador in the Atlantic. Bearded seals also occur in the Sea of Okhotsk south to the northern Sea of Japan (Figure 1). Two subspecies of bearded seals are widely recognized:Erignathus barbatus nauticusinhabiting the Pacific sector, andErignathus barbatus barbatusoften described as inhabiting the Atlantic sector (Rice, 1998). The geographic distributions of these subspecies are not separated by conspicuous gaps. There are regions of intergrading generally described as somewhere along the northern Russian and central Canadian coasts (Burns, 1981; Rice, 1998).

Although the validity of the division into subspecies has been questioned (Kosygin and Potelov, 1971), the BRT concluded, and we concur, that the evidence discussed in the status review report for retaining the two subspecies is stronger than any evidence for combining them. The BRT defined geographic boundaries for the divisions between the two subspecies, subject to the strong caveat that distinct boundaries do not appear to exist in the actual populations; and therefore, there is considerable uncertainty about the best locations for the boundaries. The BRT defined 112° W. longitude (i.e.,the midpoint between the Beaufort Sea and Pelly Bay) as the North American delineation between the two subspecies (Figure 1). Following Heptneret al.(1976), who suggested an east-west dividing line at Novosibirskiye, the BRT defined 145° E. longitude as the Eurasian delineation between the two subspecies in the Arctic (Figure 1).

Seasonal Distribution, Habitat Use, and Movements

Bearded seals primarily feed on benthic organisms that are more numerous in shallow water where light can reach the sea floor. As such, the bearded seal's effective range is generally restricted to areas where seasonal sea ice occurs over relatively shallow waters, typically less than 200 m in depth (see additional discussion below).

Bearded seals are closely associated with sea ice, particularly during the critical life history periods related to reproduction and molting, and they can be found in a broad range of different ice types. Sea ice provides the bearded seal and its young some protection from predators during the critical life history periods of whelping and nursing. It also allows molting bearded seals a dry platform to raise skin temperature and facilitate epidermal growth, and is important throughout the year as a platform for resting and perhaps thermoregulation. Of the ice-associated seals in the Arctic, bearded seals seem to be the least particular about the type and quality of ice on which they are observed. Bearded seals generally preferice habitat that is in constant motion and produces natural openings and areas of open water, such as leads, fractures, and polynyas for breathing, hauling out on the ice, and access to water for foraging. They usually avoid areas of continuous, thick, shorefast ice and are rarely seen in the vicinity of unbroken, heavy, drifting ice or large areas of multi-year ice. Although bearded seals prefer sea ice with natural access to the water, observations indicate that bearded seals are able to make breathing holes in thinner ice.

Being so closely associated with sea ice, particularly pack ice, the seasonal movements and distribution of bearded seals are linked to seasonal changes in ice conditions. To remain associated with their preferred ice habitat, bearded seals generally move north in late-spring and summer as the ice melts and retreats, and then move south in the fall as sea ice forms.

The region that includes the Bering and Chukchi Seas is the largest area of continuous habitat for bearded seals. The Bering-Chukchi Platform is a shallow intercontinental shelf that encompasses about half of the Bering Sea, spans the Bering Strait, and covers nearly all of the Chukchi Sea. Bearded seals can reach the bottom everywhere along the shallow shelf, and so it provides them favorable foraging habitat. The Bering and Chukchi Seas are generally covered by sea ice in late winter and spring, and are mostly ice free in late summer and fall. As the ice retreats in the spring most adult bearded seals in the Bering Sea are thought to move north through the Bering Strait, where they spend the summer and early fall at the southern edge of the Chukchi and Beaufort Sea pack ice and at the wide, fragmented margin of multi-year ice. A smaller number of bearded seals, mostly juveniles, remain near the coasts of the Bering and Chukchi Seas for the summer and early fall. As the ice forms again in the fall and winter, most seals move south with the advancing ice edge through Bering Strait and into the Bering Sea where they spend the winter.

There are fewer accounts of the seasonal movements of bearded seals in other areas. Compared to the dramatic long range seasonal movements of bearded seals in the Chukchi and Bering Seas, bearded seals are considered to be relatively sedentary over much of the rest of their range, undertaking more local movements in response to ice conditions. These differences may simply be the result of the general persistence of ice over shallow waters in the High Arctic. In the Sea of Okhotsk, bearded seals remain in broken ice as the sea ice expands and retreats, inhabiting the southern pack ice edge beyond the fast ice in winter and moving north toward shore in spring and summer. In the White, Barents, and Kara Seas, bearded seals also conduct seasonal migrations following the ice edge, as may bearded seals in Baffin Bay. Excluded by shorefast ice from much of the Canadian Arctic Archipelago during winter, bearded seals are scattered throughout many of the inlets and fjords of this region from July to October, though at least in some years, a portion of the population is known to overwinter in a few isolated open water areas north of Baffin Bay.

Throughout most of their range, adult bearded seals are seldom found on land. However, some adults in the Sea of Okhotsk, and more rarely in a few other regions, use haul-out sites ashore in late summer and early autumn until ice floes begin to appear at the coast. This is most common in the western Sea of Okhotsk and along the coasts of western Kamchatka where bearded seals form numerous shore rookeries that can have tens to hundreds of individuals each.


In general, female and male bearded seals attain sexual maturity around ages 5-6 and 6-7, respectively. Adult female bearded seals ovulate after lactation, and are presumably then receptive to males. Mating is believed to usually take place at the surface of the water, but it is unknown if it also occurs underwater or on land or ice, as observed in some other phocids. The social dynamics of mating in bearded seals are not well known; however, theories regarding their mating system have centered around serial monogamy and promiscuity, and on the nature of competition among breeding males to attract and gain access to females. Bearded seals vocalize during the breeding season, with a peak in calling during and after pup rearing. Male vocalizations are believed to advertise mate quality to females, signal competing males of a claim on a female, or proclaim a territory.

During the winter and spring, as sea ice begins to break up, perinatal females find broken pack ice over shallow areas on which to whelp, nurse young, and molt. A suitable ice platform is likely a prerequisite to whelping, nursing, and rearing young (Heptneret al.,1976; Burns, 1981; Reeveset al.,1992; Lydersen and Kovacs, 1999; Kovacs, 2002). Because bearded seals whelp on ice, populations have likely adapted their phenology to the ice regimes of the regions that they inhabit. Wide-ranging observations of pups generally indicate whelping occurs from March to May with a peak in April, but there are considerable geographical differences in reported timing, which may reflect real variation, but that may also result from inconsistent sighting efforts across years and locations. Details on the spatial distribution of whelping can be found in section 2.5.1 of the status review report.

Females bear a single pup that averages 33.6 kg in mass and 131.3 cm in length. Pups begin shedding their natal (lanugo) coats in utero, and they are born with a layer of subcutaneous fat. These characteristics are thought to be adaptations to entering the water soon after birth as a means of avoiding predation.

Females with pups are generally solitary, tending not to aggregate. Pups enter the water immediately after or within hours of birth. Pups nurse on the ice, and by the time they are a few days old they spend half their time in the water. Recent studies using recorders and telemetry on pups have reported a lactation period of about 24 days, a transition to diving and more efficient swimming, mother-guided movements of greater than 10 km, and foraging while still under maternal care.

Detailed studies on bearded seal mothers show they forage extensively, diving shallowly (less than 10 m), and spending only about 10 percent of their time hauled out with pups and the remainder nearby at the surface or diving. Despite the relative independence of mothers and pups, their bond is described as strong, with females being unusually tolerant of threats in order to remain or reunite with pups. A mixture of crustaceans and milk in the stomachs of pups indicates that independent foraging occurs prior to weaning, at least in some areas.


Adult and juvenile bearded seals molt annually, a process that in mature phocid seals typically begins shortly after mating. Bearded seals haul out of the water more frequently during molting, a behavior that facilitates higher skin temperatures and may accelerate shedding and regrowth of hair and epidermis. Though not studied in bearded seals, molting has been described as diffuse, with individuals potentially shedding hair throughout the year but with a pulse in the spring and summer. This is reflected in the wide range of estimates for the timing of molting, though these estimates are also based on irregular observations.

The need for a platform on which to haul out and molt from late spring to mid-summer, when sea ice is rapidly melting and retreating, may necessitate movement for bearded seals betweenhabitats for breeding and molting. In the Sea of Okhotsk, the spatial distribution of bearded seals is similar between whelping and molting seasons so only short movements occur. In contrast, bearded seals that whelp and mate in the Bering Sea migrate long distances to summering grounds at the ice edge in the Chukchi Sea, a period of movement that coincides with the observed timing of molting. Similar migrations prior to and during the molting period have been presumed for bearded seals in the White and southeastern Barents Seas to more easterly and northern areas of the Barents Sea, where ice persists through the summer. Also during the interval between breeding and molting, passive movements on ice over large distances have been postulated between the White and Barents Seas, and from there further east to the Kara Sea. A post-breeding migration of bearded seals to molting grounds has also been postulated to occur from the southern Laptev Sea westward into the eastern Kara Sea. In some locations where bearded seals use terrestrial haul-out sites seasonally, the molting period overlaps with this use. However, the molting phenology of bearded seals on shore is unknown.

Food Habits

Bearded seals are considered to be foraging generalists because they have a diverse diet with a large variety of prey items throughout their circumpolar range. Bearded seals feed primarily on a variety of invertebrates and some fishes found on or near the sea bottom. They are also able to switch their diet to include schooling pelagic fishes when advantageous. The bulk of the diet appears to consist of relatively few prey types, primarily bivalve mollusks and crustaceans like crabs and shrimps. However, fishes like sculpins, Arctic cod (Boreogadus saida), polar cod (Arctogadus glacialis), or saffron cod (Eleginus gracilis) can also be a significant component. There is conflicting evidence regarding the importance of fish in the bearded seal diet throughout its range. Several studies have found high frequencies of fishes in the diet, but it is not known whether major consumption of fish is related to the availability of prey resources or the preferential selection of prey. Seasonal changes in diet composition have been observed throughout the year. For example, clams and fishes have been reported as more important in spring and summer months than in fall and winter.

Species Delineation

The BRT reviewed the best scientific and commercial data available on the bearded seal's taxonomy and concluded that there are two widely recognized subspecies of bearded seals:Erignathus barbatus barbatus,often described as inhabiting the Atlantic sector of the seal's range; andErignathus barbatus nauticus,inhabiting the Pacific sector of the range. Distribution maps published by Burns (1981) and Kovacs (2002) provide the known northern and southern extents of the distribution. As discussed above, the BRT defined geographic boundaries for the divisions between the two subspecies (Figure 1), subject to the strong caveat that distinct boundaries do not appear to exist in the actual populations. Our DPS analysis follows.

Under our DPS policy (61 FR 4722; February 7, 1996) two elements are considered when evaluating whether a population segment qualifies as a DPS under the ESA: (1) The discreteness of the population segment in relation to the remainder of the species or subspecies to which it belongs; and (2) the significance of the population segment to the species or subspecies to which it belongs.

A population segment of a vertebrate species may be considered discrete if it satisfies either one of the following conditions: (1) It is markedly separated from other populations of the same taxon as a consequence of physical, physiological, ecological, or behavioral factors. Quantitative measures of genetic or morphological discontinuity may provide evidence of this separation; or (2) it is delimited by international governmental boundaries within which differences in control of exploitation, management of habitat, conservation status, or regulatory mechanisms exist that are significant in light of section 4(a)(1)(D) of the ESA.

If a population segment is considered to be discrete under one or both of the above conditions, its biological and ecological significance to the taxon to which it belongs is evaluated in light of the ESA's legislative history indicating that the authority to list DPSs be used “sparingly,” while encouraging the conservation of genetic diversity (see Senate Report 151, 96th Congress, 1st Session). This consideration may include, but is not limited to, the following: (1) Persistence of the discrete population segment in an ecological setting unusual or unique for the taxon; (2) evidence that loss of the discrete population segment would result in a significant gap in the range of the taxon; (3) evidence that the discrete population segment represents the only surviving natural occurrence of a taxon that may be more abundant elsewhere as an introduced population outside its historic range; or (4) evidence that the discrete population segment differs markedly from other populations of the species in its genetic characteristics.

If a population segment is discrete and significant (i.e.,it is a DPS) its evaluation for endangered or threatened status will be based on the ESA's definitions of those terms and a review of the factors enumerated in section 4(a)(1).

Evaluation of Discreteness

The range of the bearded seal occurs in cold, seasonally or annually ice-covered Arctic and subarctic waters, without persistent intrusions of warm water or other conditions that would pose potential physiological barriers. Furthermore, the seasonal timings of reproduction and molting vary little throughout the bearded seal's distribution, suggesting that there are no obvious ecological separation factors.

The underwater vocalizations of males during the breeding season recorded in Alaskan, Canadian, and Norwegian waters are often more similar between adjacent geographical regions than between more distant sites, suggesting that bearded seals may have strong fidelity to specific breeding sites. However, these observed differences in vocalizations may be due to other factors such as ecological influences or sexual selection, and not to distance or geographic barriers. Bearded seals are known to make seasonal movements of greater than 1,000 km, and so only very large geographical barriers would have the potential by themselves to maintain discreteness between breeding concentrations. As primarily benthic feeders, bearded seals may be constrained to relatively shallow waters and so expanses of deep water may also pose barriers to movement.

Erignathus barbatus nauticus:Given the bearded seal's circumpolar distribution and their ability to travel long distances, it is difficult to imagine that land masses pose a significant barrier to the movement of this subspecies, with one exception: The great southerly extent of the Kamchatka Peninsula. The seasonal ice does not extend south to the tip of that peninsula, and the continental shelf is very narrow along its eastern Bering Sea coast. The seals' affinity for ice and shallow waters may help to confine bearded seals to their respective sea basins in the Bering and Okhotsk Seas. Heptneret al.(1976) and Krylovet al.(1964) described a typical annual pattern of bearded seals in the Sea of Okhotsk to be one of staying near the ice edge when ice is present, and then moving north and closer to shore as theice recedes in summer. Unlike other researchers describing tendencies of the species as a whole, Krylovet al.(1964) described the bearded seal as more or less sedentary, based primarily on observations of seals in the Sea of Okhotsk. Indeed, published maps indicate that the southeastern coast of the Kamchatka Peninsula is the only location where the distribution of the bearded seal is not contiguous (Burns, 1981; Kovacs, 2002; Blix, 2005), and there are no known records of bearded seals moving between the Sea of Okhotsk and Bering Sea.

Kosygin and Potelov (1971) conducted a study of craniometric and morphological differences between bearded seals in the White, Barents, and Kara Seas, and bearded seals in the Bering Sea and Sea of Okhotsk. They reported differences in measurements between the three regions, although they suggested that the differences were not significant enough to justify dividing the population into subspecies. Fedoseev (1973, 2000) also suggested that differences in the numbers of lip vibrissae as well as length and weight indicate population structure between the Bering and Okhotsk Seas. Thus, under the first factor for determining discreteness, the BRT concluded, and we concur, that the available evidence indicates the discreteness of two population segments: (1) The Sea of Okhotsk, and (2) the remainder of the range ofE. b. nauticus,hereafter referred to as the Beringia population segment. Considerations of cross-boundary management do not outweigh or contradict the division proposed above based on biological grounds. In all countries in the range of the Beringia segment (Russia, United States, and Canada) annual harvest rates are considered small relative to the local populations and harvest is assumed to have little impact on abundance. In addition, if the Kamchatka Peninsula serves as a geographic barrier, the entire population of bearded seals in the Sea of Okhotsk may lie entirely within Russian jurisdiction.

Erignathus barbatus barbatus:The Greenland and Norwegian Seas, which separate northern Europe and Russia from Greenland, form a very deep basin that could potentially act as a type of physical barrier to a primarily benthic feeder. Rischet al.(2007) described distinct differences in male vocalizations at breeding sites in Svalbard and Canada; however, they also suggested that ecological influences or sexual selection, and not a geographical feature restricting gene flow, could be the cause of these differences. Gjertzet al.(2000) described at least one pup known to travel from Svalbard nearly to the Greenland coast across Fram Strait, and Daviset al.(2008) failed to find a significant difference between populations on either side of the Greenland Sea. Both of these studies suggest that the expanse of deep water is apparently not a geographic barrier to bearded seals. However, it should be noted that not all of the DNA samples used in the study by Daviset al.(2008) were collected during the time of breeding, and so might not reflect the potential for additional genetic discreteness if discrete breeding groups disperse and mix during the non-breeding period. When considered altogether, the BRT concluded, and we concur, that subdividingE. b. barbatusinto two or more DPSs is not warranted because the best scientific and commercial data available does not indicate that the populations are discrete.

The core range of the bearded seal includes the waters of five countries (Russia, United States, Canada, Greenland, and Norway) with management regimes sufficiently similar that considerations of cross-boundary management and regulatory mechanisms do not support a positive discreteness determination. In addition, in all countries in the range ofE. b. barbatus,annual harvest rates are considered small relative to the local populations and harvest is assumed to have little impact on abundance. Since we conclude that theE. b. barbatuspopulations are not discrete, we do not address whether they would be considered significant.

Evaluation of Significance

Having concluded thatE. b. nauticusis composed of two discrete segments, here we review information that the BRT found informative for evaluating the biological and ecological significance of these segments.

Throughout most of their range, adult bearded seals are rarely found on land (Kovacs, 2002). However, some adults in the Sea of Okhotsk, and more rarely in Hudson Bay (COSEWIC, 2007), the White, Laptev, Bering, Chukchi, and Beaufort Seas (Heptneret al.,1976; Burns, 1981; Nelson, 1981; Smith, 1981), and Svalbard (Kovacs and Lydersen, 2008) use haul-out sites ashore in late summer and early autumn. In these locations, sea ice either melts completely or recedes beyond the limits of shallow waters where seals are able to feed (Burns and Frost, 1979; Burns, 1981). By far the largest and most numerous and predictable of these terrestrial haul-out sites are in the Sea of Okhotsk, where they are distributed continuously throughout the bearded seal range, and may comprise tens to more than a thousand individuals (Scheffer, 1958; Tikhomorov, 1961; Krylovet al.,1964; Chugunkov, 1970; Tavrovskii, 1971; Heptneret al.,1976; Burns, 1981). Indeed, the Sea of Okhotsk is the only portion of the range ofE. b. nauticusreported to have any such aggregation of adult haul-out sites (Fay, 1974; Burns and Frost, 1979; Burns, 1981; Nelson, 1981). Although it is not clear for how long bearded seals have exhibited this haul-out behavior, its commonness is unique to the Sea of Okhotsk, possibly reflecting responses or adaptations to changing conditions at the range extremes. This difference in haul-out behavior may also provide insights about the resilience of the species to the effects of climate warming in other regions.

The Sea of Okhotsk covers a vast area and is home to many thousands of bearded seals. Similarly, the range of the Beringia population segment includes a vast area that provides habitat for many thousands of bearded seals. Loss of either segment of the subspecies' range would result in a substantially large gap in the overall range of the subspecies.

The existence of bearded seals in the unusual or unique ecological setting found in the Sea of Okhotsk, as well as the fact that loss of either the Okhotsk or Beringia segment would result in a significant gap in the range of the taxon, support our conclusion that the Beringia and Okhotsk population segments ofE. b. nauticusare each significant to the subspecies as a whole.

DPS Conclusions

In summary, the Beringia and Okhotsk population segments ofE. b. nauticusare discrete because they are markedly separated from other populations of the same taxon as a consequence of physical, physiological, ecological, and behavioral factors. They are significant because the loss of either of the two DPSs would result in a significant gap in the range of the taxon, and the Okhotsk DPS exists in an ecological setting that is unusual or unique for the taxon. We therefore conclude that these two population segments meet both the discreteness and significance criteria of the DPS policy. We consider these two population segments to be DPSs (the Beringia DPS and the Okhotsk DPS) (Figure 1).

EP10DE10.090 Abundance and Trends

No accurate worldwide abundance estimates exist for bearded seals. Several factors make it difficult to accurately assess the bearded seal's abundance and trends. The remoteness and dynamic nature of their sea ice habitat, time spent below the surface and their broad distribution and seasonal movements make surveying bearded seals expensive and logistically challenging. Additionally, the species' range crosses political boundaries, and there has been limited international cooperation to conduct range-wide surveys. Details of survey methods and data are often limited or have not been published, making it difficult to judge the reliability of the reported numbers. Logistical challenges also make it difficult to collect the necessary behavioral data to make proper adjustments to seal counts. Until very recently, no suitable behavioral data have been available to correct for the proportion of seals in the water at the time of surveys. Research is just beginning to address these limitations, and so current and accurate abundance estimates are not yet available. We make estimates based on the best scientific and commercial data available, combining recent and historical data.

Beringia DPS

Data analyzed from aerial surveys conducted in April and May 2007 produced an abundance estimate of 63,200 bearded seals in an area of 81,600 sq km in the eastern Bering Sea (Ver Hoefet al.,2010). This is a partial estimate for bearded seals in the U.S. waters of the Bering Sea because the survey area did not include some known bearded seal habitat in the eastern Bering Sea and north of St. Lawrence Island. The estimate is similar in magnitude to the western Bering Sea estimates reported by Fedoseev (2000) from surveys in 1974-1987, which ranged from 57,000 to 87,000. The BRT considers the current total Bering Sea bearded seal population to be about double the partial estimate reported by Ver Hoefet al.(2010) for U.S. waters, or approximately 125,000 individuals.

Aerial surveys flown along the coast from Shishmaref to Barrow during May-June 1999 and 2000 provided average annual bearded seal density estimates. A crude abundance estimate based on these densities, and without any correction for seals in the water, is 13,600 bearded seals. These surveys covered only a portion (U.S. coastal) of the Chukchi Sea. Assuming that the waters along the Chukchi Peninsula on the Russian side of the Chukchi Sea contain similar numbers of bearded seals, the combined total would be about 27,000 individuals.

Aerial surveys of the eastern Beaufort Sea conducted in June during 1974-1979, provided estimates that averaged 2,100 bearded seals, uncorrected for seals in the water. The ice-covered continental shelf of the western Beaufort Sea is roughly half the area surveyed, suggesting a crude estimate for the entire Beaufort Sea in June of about 3,150, uncorrected for seals in the water. For such a large area in which the subsistence use of bearded seals is important to Alaska Native and Inuvialuit communities, this number is likely to be a substantial underestimate. A possible explanation is that many of the subsistence harvests of bearded seals in this region may occur after a rapid seasonal influx of seals from the Bering and Chukchi Seas in the early summer, later than the period in which the surveys were flown.

In the East Siberian Sea, Obukhov (1974) described bearded seals as rare, but present during July-September, based on year-round observations (1959-1965) of a region extending about 350 km east from the mouth of the Kolyma River. Typically, one bearded seal was seen during 200-250 km of travel. Geller (1957) described the zone between the Kola Peninsula and Chukotka as comparatively poor in marine mammals relative to the more western and eastern portions of the northern Russian coasts. We are not aware of any other information about bearded seal abundance in the East Siberian Sea.

Although the present population size of the Beringia DPS is very uncertain, based on these reported abundance estimates, the current population size is estimated at 155,000 individuals.

Okhotsk DPS

Fedoseev (2000) presented multiple years of unpublished seal survey data from 1968 to 1990; however, specific methodologies were not provided for any of the surveys or analyses. Most of these surveys were designed primarily for ringed and ribbon seals, as they were more abundant and of higher commercial value. Recognizing the sparse documentation of the survey methods and data, as well as the 20 years or more that have elapsed since the last survey, the BRT recommends considering the 1990 estimate of 95,000 individuals to be the current estimated population size of the Okhotsk DPS.

Erignathus barbatus barbatus

Cleator (1996) suggested that a minimum of 190,000 bearded seals inhabit Canadian waters based on summing the different available indices for bearded seal abundance. The BRT recommends considering the current bearded seal population in Hudson Bay, the Canadian Archipelago, and western Baffin Bay to be 188,000 individuals. This value was chosen based on the estimate for Canadian waters of 190,000, minus 2,000 to account for the average number estimated to occur in the Canadian portion of the Beaufort Sea (which is part of theE. b. nauticussubspecies). There are few estimates of abundance available for other parts of the range ofE. b. barbatus,and there is sparse documentation of the methods used to produce these estimates. Consequently, the BRT considered all regional estimates forE. b. barbatusto be unreliable, except for those in Canadian waters. The population size ofE. b. barbatusis therefore very uncertain, but NMFS experts estimate it to be 188,000 individuals.

Summary of Factors Affecting the Bearded Seal

Section 4(a)(1) of the ESA and the listing regulations (50 CFR part 424) set forth procedures for listing species. We must determine, through the regulatory process, if a species is endangered or threatened because of any one or a combination of the following factors: (1) The present or threatened destruction, modification, or curtailment of its habitat or range; (2) overutilization for commercial, recreational, scientific, or educational purposes; (3) disease or predation; (4) inadequacy of existing regulatory mechanisms; or (5) other natural or human-made factors affecting its continued existence. These factors are discussed below, with the Beringia DPS, the Okhotsk DPS, andE. b. barbatusconsidered under each factor. The reader is also directed to section 4.2 of the status review report for a more detailed discussion of the factors affecting bearded seals (see ADDRESSES). As discussed above, data on bearded seal abundance and trends of most populations are unavailable or imprecise, and there is little basis for quantitatively linking projected environmental conditions or other factors to bearded seal survival or reproduction. Our risk assessment therefore primarily evaluated important habitat features and was based upon the best available scientific and commercial data and the expert opinion of the BRT members.

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

The main concern about the conservation status of bearded seals stems from the likelihood that their sea ice habitat has been modified by the warming climate and, more so, that the scientific consensus projections are for continued and perhaps accelerated warming in the foreseeable future. A second concern, related by the common driver of carbon dioxide (CO2) emissions, is the modification of habitat by ocean acidification, which may alter prey populations and other important aspects of the marine ecosystem. A reliable assessment of the future conservation status of bearded seals therefore requires a focus on observed and projected changes in sea ice, ocean temperature, ocean pH (acidity), and associated changes in bearded seal prey species.

The threats (analyzed below) associated with impacts of the warming climate on the habitat of bearded seals, to the extent that they may pose risks to these seals, are expected to manifest throughout the current breeding and molting range (for sea ice related threats) or throughout the entire range (for ocean warming and acidification) of each of the population units, since the spatial resolution of data pertaining to these threats is currently limited.

Overview of Global Climate Change and Effects on the Annual Formation of the Bearded Seal's Sea Ice Habitat

Sea ice in the Northern Hemisphere can be divided into first-year sea ice that formed in the most recent autumn-winter period, and multi-year sea ice that has survived at least one summer melt season. The Arctic Ocean is covered by a mix of multi-year sea ice. More southerly regions, such as the Bering Sea, Barents Sea, Baffin Bay, Hudson Bay, and the Sea of Okhotsk are known as seasonal ice zones, where first year sea ice is renewed every winter. Both the observed and the projected effects of a warming global climate are most extreme in northern high-latitude regions, in large part due to the ice-albedo feedback mechanism in which melting of snow and sea ice lowers reflectivity and thereby further increases surface warming by absorption of solar radiation.

Sea ice extent at the end of summer (September) 2007 in the Arctic Ocean was a record low (4.3 million sq km), nearly 40 percent below the long-term average and 23 percent below the previous record set in 2005 (5.6 million sq km) (Stroeveet al.,2008). Sea ice extent in September 2010 was the third lowest in the satellite record for the month, behind 2007 and 2008 (second lowest). Most of the loss of sea ice was on the Pacific side of the Arctic. Of even greater long-term significance was the loss of over 40 percent of Arctic multi-year sea ice over the last 5 years (Kwoket al.,2009). While the annual minimum of sea ice extent is often taken as an index of the state of Arctic sea ice, the recent reductions of the area of multi-year sea ice and the reduction of sea ice thickness is of greater physical importance. It would take many years to restore the ice thickness through annual growth, and the loss of multi-year sea ice makes it unlikely that the Arctic will return to previous climatological conditions. Continued loss of sea ice will be a major driver of changes across the Arctic over the next decades, especially in late summer and autumn.

Sea ice and other climatic conditions that influence bearded seal habitats are quite different between the Arctic and seasonal ice zones. In the Arctic, sea ice loss is a summer feature with a delay in freeze up occurring into the following fall. Sea ice persists in the Arctic from late fall through mid-summer due to cold and dark winter conditions. Sea ice variability is primarily determined by radiation and melting processes during the summer season. In contrast, the seasonal ice zones are free of sea ice during summer. The variability in extent, thickness, and other sea ice characteristics important to marine mammals is determined primarily by changes in the number, intensity, and track of winter and spring storms in the sub-Arctic. Although there are connections between sea ice conditions in the Arctic and the seasonal ice zones, the early loss of summer sea ice in the Arctic cannot be extrapolated to the seasonal ice zones, which are behaving differently than the Arctic. For example, the Bering Sea has had 4 years of colder than normal winter and spring conditions from 2007 to 2010, with near record sea ice extents, rivaling the sea ice maximum in the mid-1970s, despite record retreats in summer.

IPCC Model Projections

The analysis and synthesis of information presented by the IPCC in itsFourth Assessment Report(AR4) represents the scientific consensus view on the causes and future of climate change. The IPCC AR4 used a range of future greenhouse gas (GHG) emissions produced under six “marker” scenarios from theSpecial Report on Emissions Scenarios(SRES) (IPCC, 2000) to project plausible outcomes under clearly-stated assumptions about socio-economic factors that will influence the emissions. Conditional on each scenario, the best estimate and likely range of emissions were projected through the end of the 21st century. It is important to note that the SRES scenarios do not contain explicit assumptions about implementation of agreements or protocols on emission limits beyond current mitigation policies and related sustainable development practices.

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 CO2is 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 CO2and other GHGs. By contrast, warming out to about 2040-2050 will be primarily due to emissions that have already occurred and those that will occur over the next decade. Thus, conditions projected to mid-century are less sensitive to assumed future emission scenarios. Uncertainty in the amount of warming out to mid-century is primarily a function of model-to-model differences in the way that the physical processes are incorporated, and this uncertainty can be addressed in predicting ecological responses by incorporating the range in projections from different models.

Comprehensive Atmosphere-Ocean General Circulation Models (AOGCMs) are the major objective tools that scientists use to understand the complex interaction of processes that determine future climate change. The IPCC used the simulations from about two dozen AOGCMs developed by 17 international modeling centers as the basis for the AR4 (IPCC, 2007). The AOGCM 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 AOGCMs provide reliable projections, because they are built on well-known dynamical and physical principles, and they simulate quite well many large scale aspects of present-day conditions. However, the coarse resolution of most current climate models dictates careful application on small scales in heterogeneous regions.

There are three main contributors to divergence in AOGCM climate projections: Large natural variations, the range in emissions scenarios, and across-model differences. 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 arises from the range in plausible emissions scenarios. As discussed above, the impacts of the scenarios are rather similar before mid-21st century. 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). Because the current consensus is to treat all SRES emissions scenarios as equally likely, one option for representing the full range of variability in potential outcomes would be to project from any model under all of the six “marker” scenarios. This can be impractical in many situations, so the typical procedure for projecting impacts is to use an intermediate scenario, such as A1B or B2 to predict trends, or one intermediate and one extreme scenario (e.g.,A1B and A2) to represent a significant range of variability. The third primary source of variability results from differences among models in factors such as spatial resolution. This variation can be addressed and mitigated in part by using the ensemble means from multiple models.

There is no universal method for combining AOGCMs for climate projections, and there is no one best model. The approach taken by the BRT for selecting the models used to project future sea ice conditions is summarized below.

Data and Analytical Methods

NMFS scientists have recognized that the physical basis for some of the primary threats faced by the species had been projected, under certain assumptions, through the end of the 21st century, and that these projections currently form the most widely accepted version of the best available data about future conditions. In our risk assessment for bearded seals, we therefore considered the full 21st century projections to analyze the threats stemming from climate change.

The CMIP3 (IPCC) model simulations used in the BRT analyses were obtained from PCMDI on-line (PCMDI, 2010). Thesix IPCC models previously identified by Wang and Overland (2009) as performing satisfactorily at reproducing the magnitude of the observed seasonal cycle of sea ice extent in the Arctic under the A1B (“medium”) and A2 (“high”) emissions scenarios were used to project monthly sea ice concentrations in the Northern Hemisphere in March-July for each of the decadal periods 2025-2035, 2045-2055, and 2085-2095.

Climate models generally perform better on continental or larger scales, but because habitat changes are not uniform throughout the hemisphere, the six IPCC models used to project sea ice conditions in the Northern Hemisphere were further evaluated independently on their performance at reproducing the magnitude of the observed seasonal cycle of sea ice extent in 12 different regions throughout the bearded seal's range, including five regions for the Beringia DPS, one region for the Okhotsk DPS, and six regions forE. b. barbatus.Models that met the performance criteria were used to project sea ice extent for the months of November and April-July through 2100. For the Beringia DPS, in two regions (Chukchi and east Siberian Seas) six of the models simulated sea ice conditions in reasonable agreement with observations, in two regions (Beaufort and eastern Bering Seas) four models met the performance criteria, and in the western Bering Sea a single model met the performance criteria. ForE. b. barbatus,none of the models performed satisfactorily in six of the seven regions (a single model was retained in the Barents Sea). The models also did not meet the performance criteria for the Sea of Okhotsk. Other less direct means of predicting regional ice cover, such as comparison of surface air temperature predictions with past climatology (Sea of Okhotsk), evaluation of other existing analyses (Hudson Bay) or results from the hemispheric predictions (the Canadian Arctic Archipelago, Baffin Bay, Greenland Sea, and the Kara and Laptev Seas), were used for regions where ice projections could not be obtained. For Hudson Bay we referred to the analysis of Jolyet al.(2010). They used a regional sea ice-ocean model to investigate the response of sea ice and oceanic heat storage in the Hudson Bay system to a climate-warming scenario. These predicted regional sea ice conditions are summarized below in assessing the potential impacts of changes in sea ice on bearded seals.

While our inferences about future regional ice conditions are based upon the best available scientific and commercial data, we recognize that there are uncertainties associated with predictions based on hemispheric projections or indirect means. We also note that judging the timing of onset of potential impacts to bearded seals is complicated by the coarse resolution of the IPCC models.

Northern Hemisphere Predictions

Projections of Northern Hemisphere sea ice extent for November indicate a major delay in fall freeze-up by 2050 north of Alaska and in the Barents Sea. By 2090, the average sea ice concentration is below 50 percent in the Russian Arctic and some models show a nearly ice free Arctic, except for the region of the Canadian Arctic Archipelago. In March and April, winter type conditions persist out to 2090. There is some reduction of sea ice by 2050 in the outer portions of the seasonal ice zones, but the sea ice south of Bering Strait, eastern Barents Sea, Baffin Bay, and the Kara and Laptev Seas remains substantial. May shows diminishing sea ice cover at 2050 and 2090 in the Barents and Bering Seas and Sea of Okhotsk. The month of June begins to show substantial changes as the century progresses. Current conditions occasionally exhibit a lack of sea ice near the Bering Strait by June. By 2050, however, this sea ice loss becomes a major feature, with open water continuing along the northern Alaskan coast in most models. Open water in June spreads to the East Siberian Shelf by 2090. The eastern Barents Sea experiences a reduction in sea ice between 2030 and 2050. The models indicate that sea ice in Baffin Bay will be affected very little until the end of the century.

In July, the Arctic Ocean shows a marked effect of global warming, with the sea ice retreating to a central core as the century progresses. The loss of multi-year sea ice over the last 5 years has provided independent evidence for this conclusion. By 2050, the continental shelves of the Beaufort, Chukchi, and East Siberian Seas are nearly ice free in July, with ice concentrations less than 20 percent in the ensemble mean projections. The Kara and Laptev Seas also show a reduction of sea ice in coastal regions by mid-century in most but not all models. The Canadian Arctic Archipelago and the adjacent Arctic Ocean north of Canada and Greenland, however, are predicted to become a refuge for sea ice through the end of the century. This conclusion is supported by typical Arctic wind patterns, which tend to blow onshore in this region. Indeed, this refuge region is why sea ice scientists use the phrase: A nearly sea ice free summer Arctic by mid-century.

Potential Impacts of Changes in Sea Ice on Bearded Seals

In order to feed on the seafloor, bearded seals are known to nearly always occupy shallow waters (Fedoseev, 2000; Kovacs, 2002). The preferred depth range is often described as less than 200 m (Kosygin, 1971; Heptneret al.,1976; Burns and Frost, 1979; Burns, 1981; Fedoseev, 1984; Nelsonet al.,1984; Kingsleyet al.,1985; Fedoseev, 2000; Kovacs, 2002), though adults have been known to dive to around 300 m (Kovacs, 2002; Cameron and Boveng, 2009), and six of seven pups instrumented near Svalbard have been recorded at depths greater than 488 m (Kovacs, 2002). The BRT defined the core distribution of bearded seals (e.g.,whelping, nursing, breeding, molting, and most feeding) as those areas of known extent that are in water less than 500 m deep.

An assessment of the risks to bearded seals posed by climate change must consider the species' life-history functions, how they are linked with sea ice, and how altering that link will affect the vital rates of reproduction and survival. The main functions of sea ice relating to the species' life-history are: (1) A dry and stable platform for whelping and nursing of pups in April and May (Kovacset al.,1996; Atkinson, 1997); (2) a rearing habitat that allows mothers to feed and replenish energy reserves lost while nursing; (3) a habitat that allows a pup to gain experience diving, swimming, and hunting with its mother, and that provides a platform for resting, relatively isolated from most terrestrial and marine predators; (4) a habitat for rutting males to hold territories and attract post-lactating females; and (5) a platform suitable for extended periods of hauling out during molting.

Whelping and nursing:Pregnant females are considered to require sea ice as a dry birthing platform (Kovacset al.,1996; Atkinson, 1997). Similarly, pups are thought to nurse only while on ice. If suitable ice cover is absent from shallow feeding areas during whelping and nursing, bearded seals would be forced to seek either sea ice habitat over deeper water or coastal regions in the vicinity of haul-out sites on shore. A shift to whelping and nursing on land would represent a major behavioral change that could compromise the ability of bearded seals, particularly pups, to escape predators, as this is a highly developed response on ice versus land. Further, predators abound on continental shorelines, in contrast withsea ice habitat where predators are sparse; and small islands where predators are relatively absent offer limited areas for whelping and nursing as compared to the more extensive substrate currently provided by suitable sea ice.

Bearded seal mothers feed throughout the lactation period, continuously replenishing fat reserves lost while nursing pups (Holsvik, 1998; Krafftet al.,2000). Therefore, the presence of a sufficient food resource near the nursing location is also important. Rearing young in poorer foraging grounds would require mothers to forage for longer periods and (or) compromise their own body condition, both of which could impact the transfer of energy to offspring and affect survival of pups, mothers, or both.

Pup maturation:When not on the ice, there is a close association between mothers and pups, which travel together at the surface and during diving (Lydersenet al,1994; Gjertzet al.,2000; Krafftet al.,2000). Pups develop diving, swimming, and foraging skills over the nursing period, and perhaps beyond (Watanabeet al.,2009). Learning to forage in a sub-optimal habitat could impair a pup's ability to learn effective foraging skills, potentially impacting its long-term survival. Further, hauling out reduces thermoregulatory demands which, in Arctic climates, may be critical for maintaining energy balance. Hauling out is especially important for growing pups, which have a disproportionately large skin surface and rate of heat loss in the water (Hardinget al.,2005; Jansenet al.,2010).

Mating:Male bearded seals are believed to establish territories under the sea ice and exhibit complex acoustic and diving displays to attract females. Breeding behaviors are exhibited by males up to several weeks in advance of females' arrival at locations to give birth. Mating takes place soon after females wean their pups. The stability of ice cover is believed to have influenced the evolution of this mating system.

Molting:There is a peak in the molt during May-June, when most bearded seals (except young of the year) tend to haul out on ice to warm their skin. Molting in the water during this period could incur energetic costs which might reduce survival rates.

For any of these life history events, a greater tendency of bearded seals to aggregate while hauled out on land or in reduced ice could increase intra- and inter-specific competition for resources, the potential for disease transmission, and predation; all of which could affect annual survival rates. In particular, a reduction in suitable sea ice habitat would likely increase the overlap in the distribution of bearded seals and walrus (Odobenus rosmarus), another ice-associated benthic feeder with similar habitat preferences and diet. The walrus is also a predator of bearded seal, though seemingly infrequent. Hauling out closer to shore or on land could also increase the risks of predation from polar bears, terrestrial carnivores, and humans.

For a long-lived and abundant animal with a large range, the mechanisms identified above (i.e.,low ice extent or absence of sea ice over shallow feeding areas) are not likely to be significant to an entire population in any one year. Rather, the overall strength of the impacts is likely a function of the frequency of years in which they occur, and the proportion of the population's range over which they occur. The low ice years, which will occur more frequently than in the past, may have impacts on recruitment via reduced pup survival if, for example, pregnant females are ineffective or slow at adjusting their breeding locales for variability of the position of the sea ice front.

Potential mechanisms for resilience on relatively short time scales include adjustments to the timing of breeding in response to shorter periods of ice cover, and adjustments of the breeding range in response to reduced ice extent. The extent to which bearded seals might adapt to more frequent years with early ice melt by shifting the timing of reproduction is uncertain. There are many examples of shifts in timing of reproduction by pinnipeds and terrestrial mammals in response to body condition and food availability. In most of these cases, sub-optimal conditions led to reproduction later in the season, a response that would not likely be beneficial to bearded seals. A shift to an earlier melt date may, however, over the longer term provide selection pressure for an evolutionary response over many generations toward earlier reproduction.

It is impossible to predict whether bearded seals would be more likely to occupy ice habitats over the deep waters of the Arctic Ocean basin or more terrestrial habitats if sea ice fai