Endangered and Threatened Species; Designation of Critical Habitat for the Arctic Subspecies of the Ringed Seal
Federal RegisterApr 1, 2022
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Parts 223 and 226
[Docket No. 220318-0072]
RIN 0648-BC56
Endangered and Threatened Species; Designation of Critical Habitat for the Arctic Subspecies of the Ringed Seal
AGENCY:
National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.
ACTION:
Final rule.
SUMMARY:
We, the National Marine Fisheries Service (NMFS), issue this final rule to designate critical habitat for the Arctic subspecies of the ringed seal (
Pusa hispida hispida
) under the Endangered Species Act (ESA). The critical habitat designation comprises an area of marine habitat in the Bering, Chukchi, and Beaufort seas. Based on consideration of national security impacts, we have excluded an area north of the Beaufort Sea shelf from the designation.
DATES:
This rule is effective May 2, 2022.
ADDRESSES:
The final rule, critical habitat map, and associated Final Impact Analysis Report (
i.e.,
report titled “Final RIR/ESA Section 4(b)(2) Preparatory Assessment/FRFA of Critical Habitat Designation for the Arctic Ringed Seal”) can be found on the NMFS website at
www.fisheries.noaa.gov/species/ringed-seal#conservation-management.
FOR FURTHER INFORMATION CONTACT:
Tammy Olson, NMFS Alaska Region, (907) 271-5006; Jon Kurland, NMFS Alaska Region, (907) 586-7638; or Heather Austin, NMFS Office of Protected Resources, (301) 427-8422.
SUPPLEMENTARY INFORMATION:
Background
On December 28, 2012, we published a final rule to list the Arctic ringed seal as threatened under the ESA (77 FR 76706). Section 4(b)(6)(C) of the ESA requires the Secretary to designate critical habitat concurrently with listing a species as threatened or endangered unless it is not determinable at that time, in which case the Secretary may extend the deadline for this designation by one year. At the time of listing, we announced our intention to designate critical habitat for the Arctic ringed seal in a separate rulemaking, as its critical habitat was not then determinable. Concurrently, we solicited information to assist us in (1) identifying the physical or biological features essential to the conservation of Arctic ringed seals, and (2) assessing the economic impacts of designating critical habitat for this species.
On December 3, 2014, we published a proposed rule to designate critical habitat for the Arctic ringed seal under the ESA (79 FR 71714). Due to a clerical error, that document contained mistakes, and we therefore published a corrected proposed rule on December 9, 2014 (79 FR 73010). We requested public comments on this proposed designation through March 9, 2015. In response to comments, we extended the public comment period through March 31, 2015 (80 FR 5498, February 2, 2015). We held five public hearings in Alaska on the proposed rule (80 FR 1618, January 13, 2015; 80 FR 5498, February 2, 2015).
On March 17, 2016, the listing of Arctic ringed seals as a threatened species was vacated by the U.S. District Court for the District of Alaska (
Alaska Oil & Gas Ass'n
v.
Nat'l Marine Fisheries Serv.,
Case Nos. 4:14-cv-29-RRB, 4:15-cv-2-RRB, 4:15-cv-5-RRB, 2016 WL 1125744 (D. Alaska Mar. 17, 2016)). This decision was reversed by the U.S. Court of Appeals for the Ninth Circuit on February 12, 2018 (
Alaska Oil & Gas Ass'n
v.
Ross,
722 F. App'x 666 (9th Cir. 2018)), and the listing was reinstated on May 15, 2018.
On June 13, 2019, the Center for Biological Diversity filed a complaint in the U.S. District Court for the District of Alaska alleging that NMFS had failed to timely designate critical habitat for the Arctic ringed seal. Under a court-approved stipulated settlement agreement between the parties, NMFS published a revised proposed rule to designate critical habitat for the Arctic ringed seal on January 8, 2021 (86 FR 1452). Our revised proposed designation incorporated additional relevant information that became available since publication of the 2014 proposed rule, including information received during the comment period on that proposal. In the revised proposed rule, we discussed the differences from the 2014 proposal and described our revised proposed designation of critical habitat for the Arctic ringed seal. Specifically, we proposed to designate as critical habitat for the Arctic ringed seal an area of marine habitat in the northern Bering, Chukchi, and Beaufort seas containing physical and biological features essential to the conservation of the species and that may require special management considerations or protection. Based on consideration of national security impacts under section 4(b)(2) of the ESA, we also proposed to exclude an area north of the Beaufort Sea shelf from the critical habitat designation.
We requested public comments on the revised proposed designation and associated Draft Impact Analysis Report (NMFS 2020) through March 9, 2021, and held three public hearings (86 FR 7686, February 1, 2021). In response to requests, we extended the public comment period through April 8, 2021 (86 FR 13517, March 9, 2021). For a complete description of our proposed action, we refer readers to the revised proposed rule (86 FR 1452, January 8, 2021).
This final rule describes the critical habitat designation for the Arctic ringed seal and the basis for the designation, including a summary of, and responses to, comments received. A detailed discussion and analysis of probable economic impacts associated with this critical habitat designation is provided in the Final Impact Analysis Report (NMFS 2021), which is referenced throughout this final rule. The Arctic ringed seal is listed with the scientific name
Phoca
(=
Pusa
)
hispida hispida.
In this final rule, we continue to use the genus name
Pusa
to reflect currently accepted use (
e.g.,
Committee on Taxonomy (Society for Marine Mammalogy) 2019, Integrated Taxonomic Information System (online database) 2019).
Critical Habitat Definition and Process
Section 3(5)(A) of the ESA defines critical habitat as (1) the specific areas within the geographical area occupied by the species, at the time it is listed, on which are found those physical or biological features essential to the conservation of the species and which may require special management considerations or protection; and (2) specific areas outside the geographical area occupied by the species at the time it is listed, upon a determination by the Secretary of Commerce (Secretary) that such areas are essential for the conservation of the species (16 U.S.C. 1532(5)(A)). Section 3(5)(C) of the ESA provides that, except in those circumstances determined by the Secretary, critical habitat shall not include the entire geographical area which can be occupied by the threatened or endangered species. Also, by regulation, critical habitat shall not be designated within foreign countries or in other areas outside U.S. jurisdiction (50 CFR 424.12(g)).
Conservation is defined in section 3(3) of the ESA as the use of all methods
and procedures which are necessary to bring any endangered species or threatened species to the point at which the measures provided pursuant to this Act are no longer necessary (16 U.S.C. 1532(3)). Therefore, a critical habitat designation is not limited to the areas necessary for the survival of the species, but rather includes areas necessary for supporting the species' recovery. (
See Gifford Pinchot Task Force
v.
U.S. Fish and Wildlife Service,
378 F.3d 1059, 1070 (9th Cir. 2004) (“Clearly, then, the purpose of establishing `critical habitat' is for the government to carve out territory that is not only necessary for the species' survival but also essential for the species' recovery.”),
amended on other grounds,
387 F.3d 968 (9th Cir. 2004);
Alaska Oil and Gas Ass'n
v.
Jewell,
815 F.3d 544, 555-56 (9th Cir. 2016).)
Section 4(b)(2) of the ESA requires the Secretary to designate critical habitat for threatened and endangered species on the basis of the best scientific data available and after taking into consideration the economic impact, the impact on national security, and any other relevant impact of specifying any particular area as critical habitat. This section also grants the Secretary discretion to exclude any area from critical habitat if he or she determines the benefits of such exclusion outweigh the benefits of specifying such area as part of the critical habitat. However, the Secretary may not exclude areas if such exclusion will result in the extinction of the species (16 U.S.C. 1533(b)(2)).
Critical habitat designations must be based on the best scientific data available, rather than the best scientific data
possible. Bldg. Indus. Ass'n. of Superior Cal.
v.
Norton,
247 F.3d 1241, 1246-47 (D.C. Cir. 2001).
See also Alaska Oil & Gas Ass'n
v.
Jewell,
815 F.3d 544, 555 (9th Cir. 2016) (The ESA “requires use of the best available technology, not perfection.”). Provided that the best available information is sufficient to enable us to make a determination as required under the ESA, we must rely on it even though there is some degree of imperfection or uncertainty.
See Alaska
v.
Lubchenco,
825 F. Supp. 2d 209, 223 (D.D.C. 2011) (“[E]ven if plaintiffs can poke some holes in the agency's models, that does not necessarily preclude a conclusion that these models are the best available science. Some degree of predictive error is inherent in the nature of mathematical modeling.”);
Oceana, Inc.
v.
Ross,
321 F. Supp. 3d 128, 142 (D.D.C. 2018) (“[E]ven where data may be inconclusive, an agency must rely on the best available scientific information.”). There is no obligation to conduct independent studies and tests to acquire the best possible data.
Ross,
321 F. Supp. 2d at 142 (citations omitted).
See also San Luis & Delta-Mendota Water Auth.
v.
Locke,
776 F.3d 971, 995 (9th Cir. 2014) (holding that the best available science standard “does not require an agency to conduct new tests or make decisions on data that does not yet exist.”);
Am. Wildlands
v.
Kempthorne,
530 F.3d 991, 999 (D.C. Cir. 2008);
Southwest Ctr. for Biological Diversity
v.
Babbitt,
215 F.3d 58, 60 (D.C. Cir. 2000) (“The `best available data' requirement makes it clear that the Secretary has no obligation to conduct independent studies.”)
Once critical habitat is designated, section 7(a)(2) of the ESA requires Federal agencies to ensure that actions they authorize, fund, or carry out are not likely to destroy or adversely modify that habitat (16 U.S.C. 1536(a)(2)). This requirement is additional to the section 7(a)(2) requirement that Federal agencies ensure that their actions are not likely to jeopardize the continued existence of ESA-listed species (sometimes referred to as the “jeopardy” standard). Specifying the geographic location of critical habitat also facilitates implementation of section 7(a)(1) of the ESA by identifying areas where Federal agencies can focus their conservation programs and use their authorities to further the purposes of the ESA (16 U.S.C. 1536(a)(1)). Critical habitat requirements do not apply to citizens engaged in actions on private land that do not involve a Federal agency.
Description and Natural History
The Arctic ringed seal is the smallest of the northern seals, with typical adult body size of 1.5 meters (m) in length and 70 kilograms in weight (Kelly
et al.
2010a). Age of sexual maturity for female Arctic ringed seals generally ranges from 3 to 7 years of age (Smith 1987, Holst
et al.
1999, Quakenbush
et al.
2011, Crawford
et al.
2015), and for males ranges from 5 to 7 years of age (Frost and Lowry 1981), but with geographic and temporal variability depending on animal condition and population structure (Kelly
et al.
2010a). It is well established that ringed seals can live to more than 40 years of age (Kelly
et al.
2010a), and that many females surviving into their 30s remain reproductive; the average life span is likely to be much lower, due to high first-year mortality rates (Kelly 1988a).
Distribution and Habitat Use
Arctic ringed seals are circumpolar and are found throughout ice-covered waters of the Arctic Ocean Basin and southward into adjacent seas, including the Bering, Chukchi, and Beaufort seas off Alaska's coast (Frost and Lowry 1981, Frost 1985, Kelly 1988a, Rice 1998). Ringed seals are adapted to remaining in heavily ice-covered areas throughout the fall, winter, and spring by using the stout claws on their foreflippers to maintain breathing holes in the ice. Arctic ringed seals are highly associated with sea ice, and use the ice as a substrate for resting, whelping (birthing), nursing, and molting (shedding and regrowing hair and outer skin layers). The seasonality of ice cover strongly influences Arctic ringed seal movements, foraging, reproductive behavior, and vulnerability to predation. Kelly
et al.
(2010b) referred to three periods important to Arctic ringed seal seasonal movements and habitat use: The winter through early spring “subnivean period” when the seals rest primarily in subnivean lairs (snow caves on top of the ice); the late spring to early summer “basking period” between abandonment of the lairs and melting of the seasonal sea ice when the seals undergo their annual molt; and the open-water “foraging period” from ice breakup to freeze-up in the fall, when feeding occurs most intensively.
Information on movements of individual ringed seals tagged in Alaska indicates that the seals can range extensively across the Bering, Chukchi, and Beaufort seas annually (Crawford
et al.
2012a, Von Duyke 2018, Crawford
et al.
2019, Quakenbush
et al.
2019, Quakenbush 2020, Von Duyke
et al.
2020). Von Duyke
et al.
(2020) reported that during the August to December period, the median cumulative distance traveled by 17 ringed seals tagged in Alaska was 4,790 kilometers (km) per seal (range 2,719 to 5,988 km).
Subnivean Period:
With the onset of freeze-up in the fall, many Arctic ringed seals that summer in the Beaufort and Chukchi seas are thought to move generally southward with the advancing ice, while others remain in these waters over winter (Frost 1985). Adult movements during the subnivean period have been reported as typically limited, especially where ice cover is extensive (Kelly and Quakenbush 1990, Harwood
et al.
2007, Kelly
et al.
2010b, Crawford
et al.
2012b, Luque
et al.
2014), likely due to maintenance of breathing holes and social behavior during the breeding season (Kelly
et al.
2010b). For example, Kelly
et al.
(2010b) reported that the home ranges of 55 adult ringed seals inhabiting landfast (shorefast) ice in the Chukchi and Beaufort seas ranged from less than 1 to 27.9 square kilometers in April to June. However, some adult males have been found to make long-distance movements in the Chukchi and
Bering seas during January to March (Quakenbush
et al.
2019). In contrast, subadult Arctic ringed seals have been observed to travel relatively long distances to remain near the ice edge in the Bering Sea in winter (Crawford
et al.
2012a, 2019). Crawford
et al.
(2012a) suggested that this habitat may be important for overwintering subadult ringed seals; almost all of the subadults monitored by Crawford
et al.
(2019) showed this winter habitat use pattern along with dive behavior indicative of foraging.
During freeze-up, ringed seals surface to breathe in the remaining open water of cracks and leads, and as these openings in the ice freeze over, the seals open breathing holes that they maintain as the ice thickens by abrading the ice with the claws on their foreflippers (Smith and Stirling 1975). Ringed seals excavate lairs in snowdrifts over their breathing holes where snow depth is sufficient (
e.g.,
McLaren 1958, Smith and Stirling 1975, Smith 1987). These subnivean lairs are occupied for resting, whelping, and nursing pups in areas of annual landfast ice (McLaren 1958, Burns 1970, Kelly
et al.
1986, Frost and Burns 1989, Smith
et al.
1991, Oceana and Kawerak 2014) and stable pack ice (Finley
et al.
1983, Fedoseev
et al.
1988, Wiig
et al.
1999, Pilfold
et al.
2014). Snowdrifts of sufficient depth typically occur only where the ice has undergone a low to moderate amount of deformation (
i.e.,
rafting, ridging, or hummocking due to wind and ocean currents) and where snow on the ice has drifted along pressure ridges or ice hummocks (Smith and Stirling 1975, Lydersen and Gjertz 1986, Furgal
et al.
1996, Lydersen 1998).
Once mature, females give birth annually to a single pup in their lairs generally from mid-March through April, and the pups are nursed in the lairs for an average of 39 days (Hammill and Smith 1991), with considerable variation (Kelly
et al.
2010a). Females continue to forage throughout lactation while making frequent visits to birth lairs (Hammill 1987, Kelly and Wartzok 1996, Simpkins
et al.
2001). The pups develop foraging skills before weaning (Lydersen and Hammill 1993), and are normally weaned before breakup of spring ice (McLaren 1958, Smith 1973, Kelly 1988a, Smith
et al.
1991).
Subnivean lairs provide protection from cold and predators throughout the winter months, but they are especially important for protecting newborn ringed seals. The lairs conceal ringed seals from predators, an advantage especially important to pups because they start life with minimal tolerance for immersion in cold water (Smith
et al.
1991). Major predators of ringed seals include polar bears (
Ursus maritimus
) and Arctic foxes (
Alopex lagopus
) (
e.g.,
Smith 1976, Frost and Burns 1989, Derocher
et al.
2004, Thiemann
et al.
2008). Pups in lairs with thin snow cover are more vulnerable to polar bear predation than pups in lairs with thick snow cover (Hammill and Smith 1989, Ferguson
et al.
2005). For example, Hammill and Smith (1991) noted that polar bear predation on ringed seal pups increased four-fold in a year when average snow depths in their study area decreased from 23 to 10 centimeters (cm). Stirling and Smith (2004) surmised that most pups that survived exposure to cold after their subnivean lairs collapsed during unseasonal rains were eventually killed by polar bears, Arctic foxes, or gulls. Similarly, Alaska Native hunters from Kotzebue, Alaska, reported that when the snow melts early, there is no protection for ringed seal pups from predators such as jaegers, ravens, and foxes (Huntington
et al.
2017a); and hunters in the Bering Strait region suggested that other land predators (grizzly bear (
Ursus arctos
), wolverine (
Gulo gulo
)) may also prey on ringed seal pups not protected in lairs (Gadamus
et al.
2015).
Subnivean lairs also provide refuge from air temperatures too low for survival of ringed seal pups. When forced to flee into the water to avoid predators, the ringed seal pups that survive depend on the subnivean lairs to subsequently warm themselves (Smith
et al.
1991). When snow depth is insufficient, pups can freeze in their lairs, as documented when roofs of lairs in the White Sea were only 5 to 10 cm thick (Lukin and Potelov 1978). Stirling and Smith (2004) also documented exposure of ringed seals to hypothermia following the collapse of subnivean lairs during unseasonal rains near southeastern Baffin Island.
During winter and spring, ringed seals are found throughout the Chukchi and Beaufort seas (Frost 1985, Kelly 1988a). In the Bering Sea, surveys indicate that ringed seals use nearly the entire ice field over the Bering Sea shelf. During an exceptionally high ice year (1976), Braham
et al.
(1984) found ringed seals present in the southeastern Bering Sea north of the Pribilof Islands to outer Bristol Bay, primarily north of the ice front. But the authors noted that most of these seals were likely immature or nonbreeding animals. Frost (1985) indicated that ringed seals “occur as far south as Nunivak Island and Bristol Bay, depending on ice conditions in a particular year, but generally are not abundant south of Norton Sound except in nearshore areas.” More recently, surveys conducted in the Bering Sea during spring documented numerous ringed seals in both nearshore and offshore habitat, including south of Norton Sound (NMFS Marine Mammal Laboratory, 2012-2013, unpublished data). Relatively few ringed seal pups were documented during these surveys (
n
=65; Lindsay
et al.
2021), perhaps reflecting, at least in part, that pups were sheltered in subnivean lairs and thus would not have been detected during the surveys. Although highest pup densities were located in Norton Sound, pups were also documented in offshore habitat farther south (Lindsay
et al.
2021). Satellite tracking data for ringed seals tagged in Kotzebue Sound, Alaska, showed that adults remained, for the most part, in the Chukchi Sea and Bering Sea north of St. Lawrence Island during winter and spring (Crawford
et al.
2012a). However, movement data for ringed seals tagged near Utqiaġvik, Alaska, in 2011 indicated that some adults overwintered toward the shelf break in the Bering Sea (North Slope Borough, 2012, unpublished data). Ringed seals tagged more recently in the Chukchi and Beaufort seas (primarily adults) used areas as far south as Nunivak Island during December to May, but the core-use area was located in southern Kotzebue Sound (Quakenbush
et al.
2019, Quakenbush 2020). Finally, the subsistence harvest of ringed seal pups by hunters in Quinhagak, Alaska (Coffing
et al.
1998), suggests that some ringed seals may whelp south of Nunivak Island.
Basking Period:
Numbers of ringed seals hauled out on the surface of the ice typically begin to increase during spring as the temperatures warm and the snow covering the seals' lairs melts. Although the snow cover can melt rapidly, the ice remains largely intact and serves as a substrate for annual molting, during which time seals spend many hours basking in the sun (Smith 1973, Finley 1979, Smith and Hammill 1981, Kelly and Quakenbush 1990, Kelly
et al.
2010b). Adults generally molt from mid-May to mid-July (McLaren 1958), although there is regional variation (Ryg and Øritsland 1991), and pups molt at or shortly after weaning (Kelly 1988a, Lydersen and Hammill 1993). Subadult harbor seals
(Phoca vitulina
) and spotted seals (
Phoca largha
) tend to molt earlier than adults (Ashwell-Erickson
et al.
1986, Burns 2002, Daniel
et al.
2003), and this may also be the case for subadult ringed seals (Kelly and Quakenbush 1990). Usually, the largest numbers of basking seals are observed in June (Smith 1973, Finley 1979, Smith
et al.
1979, Smith and Hammill 1981, Moulton
et al.
2002a). Thometz
et al.
(2021) reported that metabolism in ringed seals increased markedly in association with the molt; and discussed that, although a study on the molt in harbor and spotted seals by Ashwell-Erickson
et al.
(1986) has often been cited as evidence of declines in metabolism, that study actually documented increasing metabolic rates during the regenerative phase of molt. Feeding is reduced during the molt, and as seals complete this phase of the annual pelage cycle and the seasonal sea ice melts during the summer, ringed seals spend increasing amounts of time in the water feeding (Kelly
et al.
2010b).
Existing information on the distribution and abundance of Arctic ringed seals in the U.S. Chukchi and Beaufort seas during the molting period comes largely from aerial surveys conducted for the most part over the continental shelf within about 25 to 40 km of the Alaska coast. However, Bengtson
et al.
(2005) reported results for spring aerial surveys conducted during two successive years in the Chukchi Sea that included a limited number of offshore (beyond 43 km from the coast) transect lines flown perpendicular from the coast up to 185 km. Ringed seals were observed along these offshore transects, albeit at lower densities than transects flown closer to the coast. Aerial surveys conducted in spring to early summer (coincident with the periods of Arctic ringed seal reproduction and molting) in the U.S. Beaufort Sea to investigate bowhead whale density and distribution were concentrated over the continental shelf, but less extensive surveys were also conducted over the adjacent shelf slope and deeper waters up to about 100 km north of the shelf (Ljungblad 1981, Ljungblad
et al.
1982, Ljungblad
et al.
1983, 1984, Ljungblad
et al.
1985, Ljungblad
et al.
1986, Alaska Fisheries Science Center 2020). Incidental sightings of ringed seals were recorded throughout the survey area, including in the limited areas surveyed north of the shelf.
Open-Water Period:
Most Arctic ringed seals that winter in the Bering and southern Chukchi seas are believed to migrate northward in spring as the ice edge recedes and spend the summer open-water period in the pack ice of the northern Chukchi and Beaufort seas (Frost 1985). Arctic ringed seals are also dispersed in ice-free areas of the Bering, Chukchi, and Beaufort seas during this period. Tracking data indicate that tagged ringed seals made extensive use of the continental shelf waters of the U.S. Chukchi and Beaufort seas during the open-water period (Crawford
et al.
2012a, Quakenbush
et al.
2019, Quakenbush 2020, Von Duyke
et al.
2020). Kelly
et al.
(2010b) found that ringed seals tagged during their study ranged during the open-water period up to 1,800 km from their small winter/spring home ranges. In addition, Harwood
et al.
(2012) documented long-distance westward movements of mostly subadult seals tagged in the Canadian Beaufort Sea through the Beaufort Sea offshore of the Alaska North Slope and continuing into the Chukchi Sea (range: 706-6,140 km).
Quakenbush
et al.
(2019) identified a high-use area for tagged ringed seals during the open-water period that included Barrow Canyon and the western Beaufort Sea over the continental shelf similar to where Citta
et al.
(2018) mapped a relatively high density of locations of tagged ringed seals during summer. Although tagged ringed seals tracked in U.S. waters tended to remain over the continental shelf, several individuals also made trips into the deep waters north of the shelf (Crawford
et al.
2019, Quakenbush
et al.
2019, Quakenbush 2020, Von Duyke
et al.
2020; Alaska Department of Fish and Game (ADF&G) and North Slope Borough, 2020, unpublished data). Von Duyke
et al.
(2020) reported that most of the forays by tagged ringed seals north of the shelf involved movements to retreating pack ice and included days when the seals hauled out on the ice. Dive recorders indicated that foraging-type movements occurred over both the continental shelf and north of the shelf, suggesting that both areas may be important during the open-water period. Similarly, during the open-water period, some, primarily subadult, ringed seals satellite-tagged in Svalbard, Norway, made forays into the Arctic Ocean Basin, and that time spent there increased after a major collapse of sea ice in this region, when the seals traveled farther to find sea ice (Hamilton
et al.
2015, Hamilton
et al.
2017). Observations of ringed seals near and beyond the outer boundary of the U.S. Exclusive Economic Zone (EEZ) north of the shelf were also documented by marine mammal observers during a research geophysical survey conducted in the summer of 2010 (Beland and Ireland 2010).
Arctic ringed seals typically lose a significant proportion of their blubber mass in late winter to early summer and then replenish their blubber reserves during late summer or fall and into winter (Lowry
et al.
1980b, Ryg
et al.
1990, Ryg and Øritsland 1991, Belikov and Boltunov 1998, Goodyear 1999, Quakenbush
et al.
2011, Young and Ferguson 2013, Quakenbush
et al.
2020).
Critical Habitat Identification
In the following sections, we describe the relevant definitions and requirements in the ESA and implementing regulations at 50 CFR part 424, and the key information and criteria used to prepare this final critical habitat designation. In accordance with section 4(b)(2) of the ESA, this critical habitat designation is based on the best scientific data available. Our primary sources of information include the status review report for the ringed seal (Kelly
et al.
2010a), our proposed and final rules to list four subspecies of ringed seals, including the Arctic ringed seal, under the ESA (75 FR 77476, December 10, 2010; 77 FR 76706, December 28, 2012), articles in peer-reviewed journals, other scientific reports, peer reviewer and public comments on the revised proposed rule, and relevant Geographic Information System (GIS) and satellite data (
e.g.,
shoreline data, U.S. maritime limits and boundaries data, sea ice extent) for geographic area calculations and mapping. We also rely upon Indigenous Knowledge (IK) of Alaska Native subsistence users.
To identify specific areas that may qualify as critical habitat for Arctic ringed seals, in accordance with 50 CFR 424.12(b), we followed a five-step process: (1) Identify the geographical area occupied by the species at the time of listing; (2) identify physical or biological habitat features essential to the conservation of the species; (3) determine the specific areas within the geographical area occupied by the species that contain one or more of the physical and biological features essential to the conservation of the species; (4) determine which of these essential features may require special management considerations or protection; and (5) determine whether a critical habitat designation limited to geographical areas occupied by the species at the time of listing would be inadequate to ensure the conservation of the species. Our evaluation and conclusions are described in detail in the following sections, and incorporate changes in response to peer reviewer and public comments (see Summary of Comments and Responses and Summary of Changes From the Revised Proposed Designation sections).
Geographical Area Occupied by the Species
The phrase “geographical area occupied by the species at the time it is listed,” which appears in the statutory
definition of critical habitat, is defined by regulation as an area that may generally be delineated around species' occurrences as determined by the Secretary (
i.e.,
range) (50 CFR 424.02). Such areas may include those areas used throughout all or part of the species' life cycle, even if not used on a regular basis, such as migratory corridors, seasonal habitats, and habitats used periodically, but not solely, by vagrant individuals (
Id.
).
Based on existing literature, including available information on Arctic ringed seal sightings and movements, we identified the range of the Arctic ringed seal in the final ESA listing rule (77 FR 76706; December 28, 2012) as the Arctic Ocean and adjacent seas, except west of 157°00′ E longitude (the Kamchatka Peninsula), where the Okhotsk subspecies of the ringed seal occurs, or in the Baltic Sea where the Baltic subspecies of the ringed seal is found. As noted previously, we cannot designate areas outside U.S. jurisdiction as critical habitat. Thus, the geographical area under consideration for this designation is limited to areas under U.S. jurisdiction that Arctic ringed seals occupied at the time of listing. This area extends to the outer boundary of the U.S. EEZ in the Chukchi and Beaufort seas, and as far south as Bristol Bay in the Bering Sea (Kelly
et al.
2010a).
Physical and Biological Features Essential to the Conservation of the Species
The statutory definition of critical habitat refers to “physical or biological features essential to the conservation of the species,” but the ESA does not specifically define or further describe these features. Implementing regulations at 50 CFR 424.02 define such features as those that occur in specific areas and that are essential to support the life-history needs of the species. The regulations provide additional details and examples of such features.
As described below in the section, Summary of Changes From the Revised Proposed Designation, peer reviewer and public comments led us to re-evaluate and revise the descriptions of the essential features identified in the revised proposed rule. Based on the best scientific information available regarding the natural history of the Arctic ringed seal and the habitat features that are essential to support the species' life-history needs, we have identified the following physical and biological features that are essential to the conservation of the Arctic ringed seal within U.S. waters occupied by the species.
(1)
Snow-covered sea ice habitat suitable for the formation and maintenance of subnivean birth lairs used for sheltering pups during whelping and nursing, which is defined as waters 3 m or more in depth (relative to MLLW) containing areas of seasonal landfast (shorefast) ice or dense, stable pack ice, that have undergone deformation and contain snowdrifts of sufficient depth to form and maintain birth lairs (typically at least 54 cm deep).
Snow-covered sea ice habitat suitable for the formation and maintenance of subnivean birth lairs used for sheltering pups during whelping and nursing is essential to conservation of the Arctic ringed seal because without the protection of lairs, ringed seal pups are more vulnerable to freezing and predation (Lukin and Potelov 1978, Smith 1987, Hammill and Smith 1991, Smith
et al.
1991, Smith and Lydersen 1991, Stirling and Smith 2004, Ferguson
et al.
2005).
Snowdrifts of sufficient depth for birth lair formation and maintenance typically occur on deformed ice where drifting has taken place along pressure ridges or ice hummocks (Smith and Stirling 1975, Lydersen and Gjertz 1986, Smith 1987, Kelly 1988a, Furgal
et al.
1996, Lydersen 1998). For purposes of assessing potential impacts of projected changes in April Northern Hemisphere snow conditions on ringed seals, Kelly
et al.
(2010a) considered 20 cm to be the minimum average snow depth required on areas of flat ice to form drifts of sufficient depth to support birth lair formation. Further, Kelly
et al.
(2010a, p. 109) discussed that ringed seals require snowdrift depths of 50 to 65 cm or more to support birth lair formation. To identify the typical snowdrift depth for snow-covered sea ice habitat that we consider sufficient for Arctic ringed seal birth lair formation and maintenance, we derived a specific depth threshold as follows. At least seven studies have reported minimum snowdrift depth measurements at Arctic ringed seal birth lairs (typically measured near the center of the lairs or over the breathing holes) off the coasts of Alaska (Kelly
et al.
1986, Frost and Burns 1989), the Canadian Arctic Archipelago (Smith and Stirling 1975, Kelly 1988b, Furgal
et al.
1996), Svalbard (Lydersen and Gjertz 1986), and in the White Sea (Lukin and Potelov 1978). The average minimum snowdrift depth measured at birth lairs was 54 cm across all of the studies combined, and 64 cm in the Alaska studies only. The average from studies in Alaska is based on data from fewer years over a shorter time span than from all seven studies combined (3 years during 1982-1984 versus 11 years during 1971-1993, respectively); consequently, the Alaska-specific average is more likely to be biased if an anomalous weather pattern occurred during its more limited timeframe. For this reason, we conclude that the average minimum snowdrift depth based on all studies combined (54 cm) provides the best available estimate of the typical minimum snowdrift depth that is sufficient for birth lairs.
Arctic ringed seals have been reported to favor landfast ice as whelping habitat (
e.g.,
Smith and Stirling 1975, 1978, Smith and Hammill 1981, Lydersen and Gjertz 1986, Smith and Lydersen 1991, Pilfold
et al.
2014). However, landfast ice extending seaward from shore may freeze to the sea bottom in very shallow water (typically less than about 1.5 to 2 m deep), such as in lagoons, near river deltas, and close to shore, during the course of winter (commonly referred to as “bottom-fast” ice; Reimnitz
et al.
1977, Newbury 1983, Hill
et al.
1991, Dammann
et al.
2018, Dammann
et al.
2019). Where sea ice in very shallow waters is bottom-fast, there would presumably be little to no ice-free water present that would allow the seals to swim under and gain access to the ice surface for the construction and maintenance of birth lairs, except perhaps where cracks form in the ice, or where the ice is not uniformly frozen to or resting on the seafloor. Thus, we expect use of bottom-fast ice by Arctic ringed seals to be low relative to use of ice in deeper waters. Although we are aware of few scientific reports or publications that provide specific information on Arctic ringed seal use of sea ice in very shallow areas during the period of whelping and nursing, Lukin
et al.
(2006) reported that in the White Sea, Arctic ringed seal breathing holes and lairs were present in water less than 3 m deep; however, no birth lairs were recorded there. In addition, a study to investigate the effects of offshore oil development on ringed seals (Williams
et al.
2002, Williams
et al.
2006) documented several lairs, including two birth lairs, as well as breathing holes, seaward of the barrier islands west of Prudhoe Bay which, based on their locations relative to depths shown on the survey maps and navigation charts, appear to have been located in water that was about 3 m or less in depth, although water depth is approximate and it is possible that sea ice conditions may differ there from those along the mainland coast. There is also some evidence that observed ringed seal densities are lower in very shallow ice-covered waters, at least in the Alaskan
Beaufort Sea during late May to early June (during the molting period) in waters less than 3 m deep (Moulton
et al.
2001, Moulton
et al.
2002b, Moulton
et al.
2002a, Moulton
et al.
2003), and in waters estimated to be between 3 and 5 m deep (Frost
et al.
2004).
The extent of landfast ice that becomes bottom-fast over winter varies along the coast (
e.g.,
Dammann
et al.
2018), and a portion of the landfast ice in very shallow waters becomes bottom-fast over winter. Use of such ice by Arctic ringed seals is expected to be low relative to use of ice in waters greater than 2 to 3 m depth, and there is some evidence that Arctic ringed seal densities are lower in waters less than 3 to 5 m deep, at least in the Beaufort Sea during late May to early June. We therefore concluded that sea ice habitat essential for birth lairs is best described in reference to a minimum water depth, rather than with a specific focus on bottom-fast ice in itself. Specifically, for the purpose of describing sea ice habitat that is essential for the formation and maintenance of birth lairs, we selected 3 m as the minimum water depth for this essential feature.
Arctic ringed seal whelping has also been observed on both nearshore and offshore drifting pack ice. As Reeves (1998) noted, nearly all research on Arctic ringed seal reproduction has been conducted in landfast ice, and the potential importance of stable but drifting pack ice has not been adequately investigated. Studies in the Barents Sea (Wiig
et al.
1999), Baffin Bay (Finley
et al.
1983) and the Canadian Beaufort Sea (Pilfold
et al.
2014) have documented pup production in pack ice, and Smith and Stirling (1975), citing unpublished data from the “Western Arctic” (presumably the Canadian Beaufort Sea), also indicated that “the offshore areas of shifting but relatively stable ice are an important part of the breeding habitat.” Lentfer (1972) reported “a significant amount of ringed seal denning and pupping on moving heavy pack ice north of Barrow [
i.e.,
Utqiaġvik].” Moreover, surveys conducted in the Bering and Chukchi seas during spring have documented ringed seals, including observations of pups, in offshore areas (NMFS Marine Mammal Laboratory, 2012-2013 and 2016, unpublished data). Ringed seal vocalizations detected throughout the winter and spring in multi-year acoustic recordings collected along the shelf break north-northwest of Utqiaġvik, along with a seasonal change in the repertoire during the breeding season, also suggest that some Arctic ringed seals overwinter and breed in offshore pack ice (Jones
et al.
2014). We therefore conclude that the best scientific information available indicates that snow-covered sea ice habitat essential for the formation and maintenance of birth lairs (in waters 3 m or more in depth relative to MLLW) includes areas of both landfast ice and dense, stable pack ice that have undergone deformation and contain snowdrifts of sufficient depth to form and maintain birth lairs, typically at least 54 cm deep.
(2)
Sea ice habitat suitable as a platform for basking and molting, which is defined as areas containing sea ice of 15 percent or more concentration in waters 3 m or more in depth (relative to MLLW).
Sea ice habitat suitable as a platform for basking and molting is essential to conservation of the Arctic ringed seal because molting is a biologically-important, energy-intensive process that could incur increased energetic costs if it were to occur in water, or increased risk of predation if it were to occur on land due to the absence of readily accessible escape routes to avoid predators (
i.e.,
breathing holes or natural openings in sea ice). Moreover, we are unaware of any studies establishing whether Arctic ringed seals can molt successfully in water, or reports of healthy Arctic ringed seals hauled out on land during the molt (they are known to come ashore during this period when sick). IK indicates that ringed seals, mostly young individuals, have been occasionally seen hauled out on land in spring near Elim, as well as south of Utqiaġvik, Alaska, although molt status was not addressed (Huntington
et al.
2015c, 2015d). If Arctic ringed seals' molt becomes more frequently interrupted by being forced to spend inordinate time in water while completing their annual molt, they could incur increased energetic costs and risk microbial infections of the skin (Fay
et al.
1978).
During their annual molt, Arctic ringed seals transition from lair use to basking on the surface of the ice for long periods of time near breathing holes, lairs, or cracks in the ice (Kelly
et al.
2010a). The relatively long periods of time that ringed seals spend out of the water during the molt (
e.g.,
Smith 1973, Smith and Hammill 1981, Kelly
et al.
2010b) have been ascribed to the need to maintain elevated skin temperatures during new hair growth (Feltz and Fay 1966, Kelly and Quakenbush 1990). Higher skin temperatures are facilitated by basking on the ice and this may accelerate shedding and regrowth of hair and skin (Feltz and Fay 1966).
Limited data are available on ice concentrations (percentage of ocean surface covered by sea ice) used by Arctic ringed seals during the basking period, in particular for the period following ice breakup. Although a number of studies have reported an apparent preference for consolidated stable ice (
i.e.,
landfast ice and consolidated pack ice), at least during the initial weeks of the basking period, some of these studies have also reported observations of Arctic ringed seals hauled out at low densities in unconsolidated ice (
e.g.,
Stirling
et al.
1982, Kingsley
et al.
1985, Lunn
et al.
1997, Chambellant
et al.
2012). Arctic ringed seals in the Chukchi Sea have also been observed basking in high densities on the last remnants of the seasonal sea ice during late June to early July, near the end of the molting period (S. Dahle, NMFS, personal communication, 2013). Crawford
et al.
(2012a) reported that the average ice concentrations (and standard error (SE), a measure of variability in the data) used by several ringed seals in the Chukchi and Bering seas during the basking period in June was 20 percent (SE = 7.8 percent) for subadults and 38 percent (SE = 21.4 percent) for adults. For a normal distribution of ice concentrations used by the seals (
i.e.,
is a bell-shaped curve), selecting the mean value for ice concentration as a lower threshold for the essential feature would exclude about half of the range of ice concentrations used by the seals. Therefore, to select a lower threshold that encompasses a majority of the ice concentrations used by the seals during molting, we subtracted one SE from each mean. The average of these adjusted values for subadults and adults (12.2 percent and 16.6 percent, respectively) is 14.4 percent. This is nearly identical to the value of 15 percent ice concentration that is commonly used to define the ice edge (National Snow and Ice Data Center (NSIDC) 2021) and for which there are spatial data layers readily available. For the purpose of describing the essential feature of sea ice habitat that is suitable as a platform for basking and molting, we selected 15 percent as the minimum ice concentration.
As discussed above, landfast ice extending seaward from shore may freeze to the sea bottom in very shallow water (typically less than about 1.5 to 2 m deep) during the course of winter and remain so into spring, potentially during part of the basking and molting period. Although some Arctic ringed seals may use very shallow ice covered waters, where ice is bottom-fast, there would presumably be little to no ice-free water present that would allow the seals to swim under and gain access to the ice
surface for basking and molting, except perhaps where cracks form in the ice, or where the ice is not uniformly frozen to or resting on the seafloor. Thus, we expect use of bottom-fast ice by Arctic ringed seals to be low relative to use of ice in deeper waters. Also, as indicated above, there is some evidence that observed ringed seal densities are lower in very shallow ice-covered waters, at least in the Alaskan Beaufort Sea during late May to early June in waters less than 3 to 5 m deep. Based on the best scientific information available, we therefore conclude that sea ice habitat essential for basking and molting is of at least 15 percent ice concentration in waters 3 m or more in depth (relative to MLLW).
(3)
Primary prey resources to support Arctic ringed seals, which are defined to be small, often schooling, fishes, in particular Arctic cod, saffron cod, and rainbow smelt; and small crustaceans, in particular, shrimps and amphipods.
Primary prey resources are essential to conservation of the Arctic ringed seal because the seals likely rely on these prey resources the most to meet their annual energy budgets. Arctic ringed seals rarely prey upon more than 10 to 15 species in any specific geographic location, and typically not more than 2 to 4 species are considered to be key prey (Węsławski
et al.
1994). Most prey are small, and preferred fishes tend to be schooling species that form dense aggregations (Kovacs 2007). Despite regional and seasonal variations in the diets of Arctic ringed seals, fishes of the cod family tend to dominate their diet in many areas from late autumn through early spring, and invertebrates can also be important in some regions, at least seasonally (as reviewed by Kelly
et al.
2010a). Although Arctic ringed seals feed on a wide variety of vertebrate and invertebrate prey species, certain prey species appear to occupy a prominent role in their diets in waters along the Alaskan coast.
Quakenbush
et al.
(2011; Tables 4-6) reported that prey items commonly consumed by ringed seals (considered for the studies discussed here to be prey items identified in at least 25 percent of ringed seal stomachs with contents) within the 1961 to 1984 and 1998 to 2009 periods in the Bering and Chukchi seas included Arctic cod, saffron cod (
Eleginus gracilis
), shrimps (from the families Hippolytidae, Pandalidae, and Crangonidae), and amphipods (primarily from the families Gammaridae and Hyperiidae). The authors found that diet composition shifted between the two periods toward an increased proportion and diversity of fish within the recent period, when other commonly consumed prey items included walleye pollock (
Theragra chalcogramma
) in the Bering Sea and rainbow smelt (
Osmerus dentex;
previously called
O. mordax
or
O. mordax dentex,
also Arctic smelt and boreal smelt in some references by authors cited herein) in the Chukchi Sea. An earlier study by Lowry
et al.
(1980b; Table 2) also indicated that ringed seals sampled in the Bering Strait region (at Nome) and in the Chukchi Sea (at Shishmaref) commonly consumed (considered here to be at least 25 percent of the total food volume in ringed seal stomachs with contents in any of the five seasonal samples) Arctic cod, saffron cod, shrimps, and amphipods (Shishmaref, specifically).
Crawford
et al.
(2015; Tables 1 and 2) indicated that prey items commonly consumed by ringed seals during May through July within the 1975 to 1984 and 2003 to 2012 periods in the Bering Strait near Diomede included Arctic cod and shrimps (for non-pup seals [≥1 year of age]); and in the Chukchi Sea near Shishmaref included saffron cod and shrimps (for both pup and non-pup seals). This study similarly found that diet composition shifted between the two periods toward an increased proportion of fish within the recent period for non-pup seals from Diomode and pups from Shishmaref. Other prey items commonly consumed within the recent period near Diomede included walleye pollock and sculpins (family Cottidae) (for non-pup seals); and near Shishmaref included rainbow smelt (for both pup and non-pup seals) and Pacific herring (
Clupea pallasi
) (24.5 percent of non-pup seals).
In addition, Quakenbush
et al.
(2020; Table 1) compared ringed seal diet in the Bering and Chukchi seas (not reported separately for each sea) by season and age class (pup and non-pup,
i.e.,
≥1 year of age) between the recent 2016 to 2020 and earlier 2000 to 2015 periods. Within both periods, during the ice-covered (November to May) and/or open-water (June to October) season, ringed seals (both pup and non-pup) commonly consumed Arctic cod, saffron cod, shrimps, and amphipods (primarily gammarids); and non-pup seals commonly consumed rainbow smelt. In addition, another prey species—capelin (
Mallotus villosus
)—was commonly consumed within the 2016 to 2020 period by pups during both seasons, and mysids (family Mysidae,
Neomysis
sp.) were commonly consumed by pups within this period during the ice-covered season.
Two studies provide limited information on the diet of ringed seals near Utqiaġvik and in the central Beaufort Sea. Dehn
et al.
(2007; Table 2) indicated that in the Utqiaġvik vicinity, prey items commonly consumed by ringed seals between 1996 and 2001 (primarily during summer) included euphausiids (
Thysanoessa
spp.), cods (primarily Arctic and saffron cod), mysids (
Mysis
and
Neomysis
spp.), amphipods, and pandalid shrimps. In addition, Frost and Lowry (1984; Table III) found that prey items commonly consumed by ringed seals (considered here to be at least 25 percent of the mean total food volume in ringed seal stomachs with contents in any of the three seasonal samples) collected near Utqiaġvik and in the central Beaufort Sea (approximately 80 km northwest of Prudhoe Bay and near Pingok Island and Beaufort Lagoon), primarily between 1977 and 1980, included Arctic cod, as well as gammarid and hyperiid amphipods.
IK about ringed seals documented for coastal communities located in western and northern Alaska aligns in general with the ringed seal diet information from the studies reviewed above. Alaska Native hunters interviewed in several communities in the Bering Strait region, as well as in two communities in the northern Bering Sea region, reported that ringed seals feed on Pacific herring, in particular during spawning (
e.g.,
Oceana and Kawerak 2014, Gadamus
et al.
2015, Huntington
et al.
2016, 2017c, 2017b). Other prey species reported for ringed seals in these regions included fishes such as capelin, saffron cod, Arctic cod, sculpins, salmon, and whitefish species, as well as invertebrates such as shrimps and crabs (Nelson 1981, Huntington 2000, Oceana and Kawerak 2014, Gadamus
et al.
2015, Huntington
et al.
2015c, 2015a, 2016, 2017b), and near Wainwright in the Chukchi Sea included smelt, saffron cod, and invertebrates such as shrimps (Nelson 1981).
In summary, Arctic cod, saffron cod, shrimps, and amphipods were identified as prominent prey species for the studies conducted in both the Bering Sea and the Chukchi Sea, and Arctic cod and amphipods were also identified as prominent prey species for ringed seals sampled near Utqiaġvik and in the central Beaufort Sea. Rainbow smelt was also a prominent prey species since about 2000 in the Bering and/or Chukchi seas. Several other prey species were reported as commonly consumed by ringed seals, but these reports were more spatially and temporally limited. Still, diet composition and the relative prominence of certain prey species varied both geographically and seasonally, and differences in diet between age classes (pups and non-pup
seals), as well as a temporal shift in diet in the Bering and Chukchi seas, have been reported. In addition, ringed seal diet information for the Beaufort Sea is relatively limited. Therefore, based on the best scientific data available, we conclude that small, often schooling, fishes, in particular, Arctic cod, saffron cod, and rainbow smelt; and small crustaceans, in particular, shrimps and amphipods, are the primary prey resources of Arctic ringed seals in U.S. waters. We find that this level of specificity, naming species known to be prominent in Arctic ringed seals' diet but not limiting the definition to only those species, is most appropriate for defining this essential feature based on the best scientific data available. Because Arctic ringed seals feed on a variety of prey items and regional and temporal differences in diet have been reported, we conclude that areas in which the primary prey essential feature occurs are those that contain one or more of these particular prey resources.
Specific Areas Containing the Essential Features
To determine which areas qualify as critical habitat within the geographical area occupied by the species, we are required to identify “specific areas” that contain one or more of the physical or biological features essential to the conservation of the species (and that may require special management considerations or protection, as described below) (50 CFR 424.12(b)(1)(iii)). Delineation of the specific areas is done at a scale determined by the Secretary to be appropriate (50 CFR 424.12(b)(1)). Regulations at 50 CFR 424.12(c) also require that each critical habitat area be shown on a map.
In determining the scale and boundaries for the specific areas, we considered, among other things, the scales at which biological data are available and the availability of standardized geographical data necessary to map boundaries. Because the ESA implementing regulations allow for discretion in determining the appropriate scale at which specific areas are drawn (50 CFR 424.12(b)(1)), we are not required, nor was it possible, to determine whether each square inch, acre, or even square mile independently meets the definition of “critical habitat.” A main goal in determining and mapping the boundaries of the specific areas is to provide a clear description and documentation of the areas containing the identified essential features. This is ultimately fundamental to ensuring that Federal action agencies are able to determine whether their particular actions may affect the critical habitat.
As described below in the section Summary of Changes From the Revised Proposed Designation, after revising the proposed definitions of the essential features, and in response to public comments that expressed concerns regarding our proposed delineation of the boundaries of critical habitat with respect to the primary prey resources essential feature, we re-evaluated the best scientific data available to ensure that those boundaries were drawn appropriately. As a result, we now identify one specific area that contains the primary prey resources essential feature in addition to the sea ice essential features as described in this section.
As we explain below, the essential features of Arctic ringed seal critical habitat, in particular the sea ice essential features, are dynamic and variable on both spatial and temporal scales. Arctic ringed seal movements and habitat use are strongly influenced by the seasonality of sea ice, and the seals can range widely in response to the specific locations of the most suitable habitat conditions. Based on the best scientific data available, we have therefore identified one specific area that comprises parts of the Bering, Chukchi, and Beaufort seas, within which all of the identified essential features can be found in any given year.
We first focused on identifying where sea ice essential features occur that support the species' life history functions of whelping and nursing (when birth lairs are constructed and maintained) and molting. As discussed above, Arctic ringed seals are highly associated with sea ice, and the seals tend to migrate seasonally to maintain access to the ice. Arctic ringed seal whelping, nursing, and molting takes place in the Bering, Chukchi, and Beaufort seas. Therefore, we considered where the sea ice essential features occur in all of these waters.
The dynamic nature of sea ice and the spatial and temporal variations in sea ice and on-ice snow cover conditions constrain our ability to map precisely the specific geographic locations where the sea ice essential features occur. Sea ice characteristics such as ice extent, ice concentration, and ice surface topography vary spatiotemporally (
e.g.,
Iacozza 2011). Snowdrift depths on sea ice are also spatiotemporally variable, as drifting of snow is determined by characteristics of the ice, such as surface topography and weather conditions (
e.g.,
wind speed/direction and snowfall amounts), among other factors (Iacozza and Ferguson 2014). The specific geographic locations of essential sea ice habitat used by Arctic ringed seals vary from year to year, or even day to day, depending on many factors, including time of year, local weather, and oceanographic conditions (
e.g.,
Frost
et al.
1988, Frost
et al.
2004, Gadamus
et al.
2015). In addition, the duration that sea ice habitat essential for birth lairs, or for basking and molting, is present in any given location can vary annually depending on the rate of ice melt and other factors. The temporal overlap of Arctic ringed seal molting with whelping and nursing, combined with the dynamic nature of sea ice and on-ice snow depths, also makes it impracticable to separately identify specific areas where each of these essential features occurs. However, it is unnecessary to distinguish between specific areas containing sea ice essential for birth lairs and sea ice essential for basking and molting because the ESA permits the designation of critical habitat where one or more essential features occur.
Arctic ringed seals can range widely, which, combined with the dynamic variations in sea ice and on-ice snow depths, results in individuals distributing broadly and using sea ice habitats within a range of suitable conditions. We integrated these physical and biological factors into our identification of specific areas where one or both sea ice essential features occur by considering the information currently available on the seasonal distribution and movements of Arctic ringed seals during the annual period of reproduction and molting, along with satellite-derived estimates of the position of the sea ice edge over time. Although this approach allowed us to identify specific areas that contain one or both of the sea ice essential features at certain times, the available data supported delineation of specific areas only at a coarse scale. Consequently, we delineated a single specific area that contains the sea ice features essential to the conservation of Arctic ringed seals, as follows.
We first identified the southern boundary of this specific area. We relied on the birth lair essential feature to determine the southern boundary of critical habitat because peak molting (for adults) takes place later in the spring as sea ice retreats northward, and also because the annual extent and timing of sea ice are especially variable in the southern periphery of the Arctic ringed seal's habitat in the Bering Sea (Boveng
et al.
2009, Stabeno
et al.
2012, Frey
et al.
2015). Consequently, we concluded that the southern extent of sea ice suitable for birth lairs also
provides the best estimate of the southern extent of sea ice suitable for basking and molting.
As discussed in detail below, because existing information is limited on whelping locations and the distribution of Arctic ringed seals in the Bering Sea during spring, a precise southern boundary for the critical habitat cannot be determined based on such information. Available estimates of snow-depth on Arctic sea ice derived from satellite remote-sensing data are spatially and temporally limited and are subject to a variety of sources of uncertainty (Spreen and Kern 2017, Sturm and Massom 2017, Webster
et al.
2018). Further, there is a high degree of variability in snow depths on sea ice and the spatial distribution of those depths within and between years (Sturm and Massom 2017, Webster
et al.
2018). We therefore turned to Sea Ice Index data maintained by the NSIDC (Fetterer
et al.
2017, Version 3.0, accessed November 2019) for information on the estimated monthly position of the ice edge in the Bering Sea during spring based on a time series of satellite records. Although April is the peak month for ringed seal whelping, snow-covered sea ice would need to persist for several weeks for pups to be sheltered and nursed in birth lairs. We therefore considered information on the position of the ice edge in the Bering Sea during May to assess whether basing the southern boundary on this ice edge (rather than the April ice edge) would most accurately represent the southern extent of where the birth lair essential feature occurs on a consistent basis. We examined the estimated position of the May median ice edge for both the 30-year 1981 to 2010 reference period currently used by NSIDC for the Sea Ice Index, and for the more recent 30-year period of 1990 to 2019, which was calculated using methods and data types similar to those used for the Sea Ice Index. We note that the two most recent years included in the 1990 to 2019 period had record low ice extent in the Bering Sea (Stabeno and Bell 2019). The May median ice edge from the Sea Ice Index is located about 22 km southwest of St. Matthew Island and about 85 km north of Nunivak Island, and for the more recent 1990 to 2019 period, is generally similar to that of the Sea Ice Index, except that east of St. Matthew Island the ice edge for the more recent period has a more variable shape. As a result, although the median ice edge for both 30-year periods reaches the coast at a similar location south of Hooper Bay, between that location and St. Matthew Island, the median ice edge for the more recent period is primarily located north of Hooper Bay.
To inform our evaluation of the above information relative to determining the southern boundary, we considered data available on the spring distribution of ringed seals in the Bering Sea from aerial surveys conducted in in 2012 and 2013 (NMFS Marine Mammal Laboratory, 2012-2013, unpublished data). Briefly, these surveys collected paired thermal and high-resolution digital imagery. Semi-automated techniques were used to detect seals from the thermal imagery, and expert observers then assigned species and age class to the detections from the associated photographs (Moreland
et al.
2013). For the revised proposed designation, we considered information on the spatial distribution of ringed seal detections (with species identification confidence classified as “positive” or “likely”). After the revised proposed designation was published, a scientific publication by Lindsay
et al.
(2021) became available that produced maps of ringed seal densities from the aerial survey dataset (based on ringed seal detections for all values of species identification confidence). We therefore considered this information in developing the final designation. Overall, ringed seal densities in the Bering Sea appeared to be higher in areas proximate to and north of St. Matthew and Nunivak Islands (as compared to areas surveyed farther south toward the shelf break), with highest densities in Norton Sound, although ringed seals were documented as far south as Bristol Bay. Relatively few ringed seal pups were documented during these surveys (perhaps reflecting, at least in part, that pups were sheltered in subnivean lairs and thus would not have been detected during the surveys). Although pup densities were highest in Norton Sound, pups were also documented in offshore habitat, primarily proximate to and north of St. Matthew and Nunivak Island, and several pups were detected in offshore areas farther south.
Taken as a whole, we concluded that the best scientific data available on the spring distribution of ringed seals in the Bering Sea suggests that the median position of the ice edge for May provides the best estimate of the southern extent of where the birth lair essential feature occurs on a consistent basis. In drawing this conclusion, we took into consideration that the 2012 and 2013 surveys were conducted in years with above-average ice extent and that our focus in delineating the southern boundary is on identifying the best estimate of the southern extent of where the birth lair essential feature (and potentially sea ice essential for molting) occurs on a consistent basis in more than limited areas. Given the reduction in sea ice east of St. Matthew Island between the reference period used for the Sea Ice Index and the more recent 30-year period described above, we elected to base the southern boundary on the estimated position of the May median ice edge for the more recent 1990 to 2019 period. Because Arctic ringed seals use nearly the entire ice field over the Bering Sea shelf in the spring, depending upon ice conditions in a given year, some ringed seals may use sea ice for whelping south of the southern boundary described above. But we concluded that the variability in the annual extent and timing of sea ice in this southernmost portion of the Arctic ringed seal's range in the Bering Sea (
e.g.,
Boveng
et al.
2009, Stabeno
et al.
2012, Frey
et al.
2015) renders these waters unlikely to contain the sea ice essential features on a consistent basis in more than limited areas.
To simplify the southern boundary for purposes of delineation on maps, we modified the line representing the May median ice edge for the 1990 to 2019 period as follows: (1) Intermediate points along this line between its intersection point with the seaward limit of the U.S. EEZ (61°18′15″ N/177°45′56″ W) and the point southwest of St. Matthew Island where it turns northeastward (60°7′ N/172°1′ W) were removed to form the segment of the southern boundary that extends from the seaward limit of the U.S. EEZ southeastward approximately 340 km; and (2) intermediate points along this line between the point southwest of St. Matthew Island and the point where it reaches the coast near Cape Romanzof were removed and connected to the coast to form the second segment of the southern boundary that extends northeastward approximately 370 km (at 61°48′42″ N/166°6′5″ W). This editing produced a simplified southern boundary that retains the general shape of the original line representing the May median ice edge.
We then identified the northern boundary of the specific area that contains one or both of the sea ice essential features. As discussed above, Arctic ringed seals have a widespread distribution, including in offshore pack ice. The period during which ringed seals bask and molt overlaps with when many ringed seals also migrate north with the receding ice edge. In addition, sea ice and on-ice snow depths are dynamic and variable on both spatial and temporal scales, and sea ice suitable
for basking and molting, and potentially for birth lairs, occurs over waters extending up to and beyond the seaward limit of the U.S. EEZ (see,
e.g.,
Fetterer
et al.
2017, Sea Ice Index Version 3.0, accessed November 2019, Blanchard-Wrigglesworth
et al.
2018). We therefore concluded that the outer limit of the U.S. EEZ to the north, west, and east best defines the remaining seaward boundaries of the area containing the sea ice essential features. We note that Canada contests the limits of the U.S. EEZ in the eastern Beaufort Sea, asserting that the line delimiting the two countries' EEZs should follow the 141st meridian out to a distance of 200 nautical miles (nm) as opposed to an equidistant line that extends seaward perpendicular to the coast at the U.S.-Canada land border. Finally, we defined the shoreward boundary of the specific area delineated for the sea ice essential features as the 3-m isobath (relative to MLLW), consistent with the 3-m minimum water depth identified for both features.
The primary prey species essential to support Arctic ringed seals are found in a range of habitats in U.S. waters occupied by these seals. For example, amphipods documented in the diet of Arctic ringed seals in U.S. waters include the pelagic hyperiid amphipod
Parathemisto libellula;
gammarid amphipod species that inhabit the underside of sea ice; and benthic amphipods and shrimps, which were well represented in sampling conducted for benthic assessments in the Beaufort, Chukchi, and northern Bering seas (
e.g.,
Bluhm
et al.
2009, Goddard
et al.
2014, Ravelo
et al.
2014, Grebmeier
et al.
2015, Ravelo
et al.
2015, Sigler
et al.
2017). Notably, Arctic cod and saffron cod make up a substantial portion of the fish biomass in the U.S. Chukchi Sea and Arctic cod dominates the fish biomass in the U.S. Beaufort Sea (North Pacific Fishery Management Council 2009, Logerwell
et al.
2015). Arctic cod are widely distributed, and are regularly observed in association with sea ice, but they are also found in seasonally ice-free waters (Bluhm and Gradinger 2008, Love
et al.
2016, Mecklenburg
et al.
2016). Arctic cod have been documented in surveys of the Beaufort Sea and Chukchi Sea shelf and slope (
e.g.,
Frost and Lowry 1983, Parker-Stetter
et al.
2011, Crawford
et al.
2012b, Logerwell
et al.
2015, Norcross
et al.
2017a, Norcross
et al.
2017b, Forster
et al.
2020), and their general distribution extends northward into deeper waters off the shelf (Cohen
et al.
1990, Love
et al.
2016, Mecklenburg
et al.
2016), where Arctic cod were observed in water wedges along the edges of summer pack ice floes, along with amphipods under the ice, and diving ringed seals were observed at numerous locations (Gradinger and Bluhm 2004). The southern extent of the distribution of Arctic cod and its abundance in the northern and eastern Bering Sea are more limited and linked to the extent of ice cover and associated cold bottom temperatures (Love
et al.
2016, Mecklenburg
et al.
2016, Forster 2019, Marsh and Mueter 2019). The distribution of saffron cod overlaps to some extent with that of Arctic cod in the Chukchi and Beaufort seas, but this species is typically found in warmer water and has a more shallow coastal distribution that extends farther south in the Bering Sea (Love
et al.
2016, Mecklenburg
et al.
2016). Similarly, rainbow smelt are found primarily in shallow coastal waters of the Bering, Chukchi, and Beaufort seas (Haldorson and Craig 1984, Burns 1990, Logerwell
et al.
2015, Love
et al.
2016, Ormseth 2019).
In summary, the available data on the distributions of Arctic ringed seal primary prey species indicate that they occur throughout the geographical area occupied by the species. However, except in limited circumstances that do not apply here, the Secretary cannot designate as critical habitat the entire geographical area occupied by a species. We have no information that suggests any portions of the species' occupied habitat contain prey species that are of greater importance or otherwise differ from those found within the specific area defined by the sea ice essential features. Although ringed seals may forage seasonally in some particular areas, such as Barrow Canyon, the seals also make extensive use of a diversity of habitats for foraging across much broader areas in the Bering, Chukchi, and Beaufort seas. Most importantly, the movements and habitat use of Arctic ringed seals are strongly influenced by the seasonality of sea ice and they forage throughout the year (albeit with reduced feeding during molting). Given this and our consideration of the best scientific data available, we concluded that the best approach to determine the appropriate boundaries for critical habitat is to base the delineation on the boundaries identified above for the sea ice essential features. We conclude this specific area contains sufficient primary prey resources to support the conservation of Arctic ringed seals. Thus, we are designating as critical habitat a single specific area that contains all three of the identified essential features.
Special Management Considerations or Protection
A specific area within the geographic area occupied by a species may only be designated as critical habitat if the area contains one or more essential physical or biological feature that may require special management considerations or protection (16 U.S.C. 1532(5)(A)(i); 50 CFR 424.12(b)(1)(iv)). “Special management considerations or protection” is defined as methods or procedures useful in protecting the physical or biological features essential to the conservation of listed species (50 CFR 424.02). In determining whether the essential physical or biological features “may require” special management considerations or protection, it is necessary to find only that there is a possibility that the features may require special management considerations or protection in the future; it is not necessary to find that such management is presently or immediately required.
Home Builders Ass'n of N. California
v.
U.S. Fish and Wildlife Serv.,
268 F. Supp. 2d 1197, 1218 (E.D. Cal. 2003). The relevant management need may be “in the future based on possibility.”
Bear Valley Mut. Water Co.
v.
Salazar,
No. SACV 11-01263-JVS, 2012 WL 5353353, at *25 (C.D. Cal. Oct. 17, 2012).
See also Cape Hatteras Access Pres. Alliance
v.
U.S. Dept. of Interior,
731 F. Supp. 2d 15, 24 (D.D.C. 2010) (“The Court explained in CHAPA I that `the word “may” indicates that the requirement for special considerations or protections need not be immediate' but must require special consideration or protection `in the future.' ”) (citing
Cape Hatteras Access Pres. Alliance
v.
U.S. Dept. of Interior,
344 F. Supp. 2d 108, 123-24 (D.D.C. 2004)).
We have identified four primary sources of potential threats to one or more of the habitat features identified above as essential to the conservation of Arctic ringed seals: Climate change; oil and gas exploration, development, and production; marine shipping and transportation; and commercial fisheries. As further detailed below, both sea ice essential features and the primary prey essential feature may require special management considerations or protection as a result of impacts (either independently or in combination) from these sources. Our evaluation does not consider an exhaustive list of threats that could have impacts on the essential features, but rather considers the primary potential threats that we are aware of at this time that support our conclusion that special management considerations or
protection of each of the essential features may be required. Further, we highlight particular threats associated with each source of impacts while recognizing that certain threats are associated with more than one source (
e.g.,
marine pollution and noise).
Climate Change
The principal threat to the persistence of the Arctic ringed seal is anticipated loss of sea ice and reduced on-ice snow depths stemming from climate change. Climate-change-related threats to the Arctic ringed seal's habitat are discussed in detail in the ringed seal status review report (Kelly
et al.
2010a), as well as in our proposed and final rules to list the Arctic ringed seal as threatened. Total Arctic sea ice extent has been showing a decline through all months of the satellite record since 1979 (Meier
et al.
2014). Although there will continue to be considerable annual variability in the rate and timing of the breakup and retreat of sea ice, trends in climate change are moving toward ice that is more susceptible to melt (Markus
et al.
2009), and areas of earlier spring ice retreat (Stammerjohn
et al.
2012, Frey
et al.
2015). Notably, February and March ice extent in the Bering Sea in 2018 and 2019 were the lowest on record (Stabeno and Bell 2019), and in the spring of 2019, melt onset in the Chukchi Sea occurred 20 to 35 days earlier than the 1981 to 2010 average (Perovich
et al.
2019). Along with reductions in the extent and timing of sea ice cover, observations indicate a decline in spring snow depth on Arctic ice attributed to later sea ice formation in autumn (Webster
et al.
2014, Webster
et al.
2018), and a trend toward earlier spring rain-on-snow events throughout much of the Arctic Ocean in recent decades (Dou
et al.
2021). Based on climate models, a study by Hezel
et al.
(2012) projected a substantial decline over this century in average snow depth on Arctic sea ice.
Activities that release carbon dioxide and other heat-trapping greenhouse gases (GHGs) into the atmosphere, most notably those that involve fossil fuel combustion, are the major contributing factor to climate change and loss of sea ice (Intergovernmental Panel on Climate Change (IPCC) 2013, U.S Global Climate Change Research Program 2017, Stroeve and Notz 2018, IPCC 2021). Such activities may adversely affect the essential features of Arctic ringed seal habitat by diminishing snow-covered sea ice suitable for birth lairs and sea ice suitable for basking and molting, and by causing changes in the distribution, abundance, and/or species composition of prey resources (including Arctic ringed seal primary prey resources) in association with changes in ocean conditions, such as warming and acidification (caused primarily by uptake of atmospheric CO
2
) (as reviewed by Kelly
et al.
2010a, also,
e.g.,
Kortsch
et al.
2015, Alabia
et al.
2018, Arctic Monitoring and Assessment Programme (AMAP) 2018, Holsman
et al.
2018, Thorson
et al.
2019, Baker
et al.
2020, Huntington
et al.
2020). Declines in the extent and timing of sea ice cover may also lead to increased shipping activity (discussed below) and other changes in anthropogenic activities, with the potential for increased risks to the habitat features essential to Arctic ringed seal conservation (Kelly
et al.
2010a). Given that the quality and quantity of these essential features, in particular sea ice, may be diminished by the effects of climate change, we conclude that special management considerations or protection may be necessary, either now or in the future.
Oil and Gas Activity
Oil and gas exploration, development, and production activities in the U.S. Arctic may include: Seismic surveys; exploratory, delineation, and production drilling operations; construction of artificial islands, causeways, ice roads, shore-based facilities, and pipelines; and vessel and aircraft operations. These activities have the potential to affect the essential features of Arctic ringed seal critical habitat, primarily through pollution (particularly in the event of a large oil spill), noise, and physical alteration of the species' habitat.
Large oil spills (considered in this section to be spills of relatively great size, consistent with common usage of the term) are generally considered to be the greatest threat associated with oil and gas activities in the Arctic marine environment (AMAP 2007). Experiences with spills in subarctic regions, such as in Prince William Sound, Alaska, have shown that large oil spills can have lasting ecological effects (AMAP 2007, Barron
et al.
2020). In contrast to spills on land, large spills at sea, especially when ice is present, are difficult to contain or clean up (National Research Council 2014, Wilkinson
et al.
2017). Responding to a sizeable spill in the Arctic environment would be particularly challenging. Reaching a spill site and responding effectively would be especially difficult, if not impossible, in winter when weather can be severe and daylight extremely limited. Oil spills under ice or in ice-covered waters are the most challenging to deal with due to, among other factors, limitations on the effectiveness of current containment and recovery technologies when sea ice is present (Wilkinson
et al.
2017). The extreme depth and the pressure that oil was under during the 2010 blowout at the Deepwater Horizon well in the Gulf of Mexico may not exist in the shallow continental shelf waters of the Beaufort and Chukchi seas. Nevertheless, the difficulties experienced in stopping and containing the Deepwater Horizon blowout, where environmental conditions, available infrastructure, and response preparedness were comparatively good, point toward even greater challenges in containing and cleaning a large spill in a much more environmentally severe and geographically remote Arctic location.
Although planning, management, and use of best practices can help reduce risks and impacts, the history of oil and gas activities indicates that accidents cannot be eliminated (AMAP 2007). Data on large spills (
e.g.,
operational discharges, spills from pipelines, blowouts) in Arctic waters are limited because oil exploration and production there has been limited. The Bureau of Ocean Energy Management (BOEM) (2011) estimated the chance of one or more oil spills greater than or equal to 1,000 barrels occurring if development were to take place in the Beaufort Sea or Chukchi Sea Planning Areas as 26 percent for the Beaufort Sea over the estimated 20 years of production and development, and 40 percent for the Chukchi Sea over the estimated 25 years of production and development.
Icebreaking vessels, which may be used for in-ice seismic surveys or to manage ice near exploratory drilling ships, also have the potential to affect the sea ice essential features of Arctic ringed seal critical habitat through physical alteration of the sea ice (see also
Marine Shipping and Transportation
section). Other examples of activities associated with oil and gas exploration and development that may physically alter the essential sea ice features include construction and maintenance of offshore ice roads, ice pads, and camps, as well as other offshore through-ice activities such as trenching and installation of pipelines. In addition, there is evidence that noise associated with activities such as seismic surveys can result in behavioral and other effects on fishes and invertebrate species (Carroll
et al.
2017, Slabbekoorn
et al.
2019), although the available data on such effects are currently limited, in particular for invertebrates (Hawkins
et al.
2015, Hawkins and Popper 2017), and the nature of potential effects specifically
on the primary prey resources of Arctic ringed seals are unclear.
In summary, a large oil spill could render areas containing the identified essential features unsuitable for use by Arctic ringed seals. In such an event, sea ice habitat essential for whelping, nursing, and/or for basking and molting could be oiled. Arctic ringed seal primary prey resources could also become contaminated, experience mortality, or be otherwise adversely affected by spilled oil. In addition, disturbance effects (both physical alteration of habitat and acoustic effects) could alter the quality of the essential features of Arctic ringed seal critical habitat, or render habitat unsuitable. We conclude that the essential features of the habitat of the Arctic ringed seal may require special management considerations or protection in the future to minimize the risks posed to these features by oil and gas exploration, development, and production.
Marine Shipping and Transportation
The reduction in Arctic sea ice that has occurred in recent years has renewed interest in using the Arctic Ocean as a potential waterway for coastal, regional, and trans-Arctic marine operations and in extension of the navigation season in surrounding seas (Brigham and Ellis 2004, Arctic Council 2009). Marine traffic along the western and northern coasts of Alaska includes tug, towing, and cargo vessels, tankers, research and government vessels, vessels associated with oil and gas exploration and development, fishing vessels, and cruise ships (Adams and Silber 2017, U.S. Committee on the Marine Transportation System 2019). Automatic Identification System data indicate that the number of unique vessels operating annually in U.S. waters north of the Bering Sea in 2015 to 2017 increased 128 percent over the number recorded in 2008 (U.S. Committee on the Marine Transportation System 2019). Climate models predict that the warming trend in the Arctic will accelerate, causing the ice to begin melting earlier in the spring and resume freezing later in the fall, resulting in an expansion of potential transit routes and a lengthening of the potential navigation season, and a continuing increase in vessel traffic (Khon
et al.
2010, Smith and Stephenson 2013, Stephenson
et al.
2013, Huntington
et al.
2015b, Melia
et al.
2016, Aksenov
et al.
2017, Khon
et al.
2017). For instance, analysis of four potential growth scenarios (ranging from reduced activity to accelerated growth) suggests from 2008 to 2030, the number of unique vessels operating in U.S. waters north of 60° N (
i.e.,
northern Bering Sea and northward) may increase by 136 to 346 percent (U.S. Committee on the Marine Transportation System 2019).
The fact that nearly all vessel traffic in the Arctic, with the exception of icebreakers, purposefully avoids areas of ice, and primarily occurs during the ice-free or low-ice seasons, helps to mitigate the risks of shipping to the essential habitat features identified for Arctic ringed seals. However, icebreakers pose greater risks to these features since they are capable of operating year-round in all but the heaviest ice conditions and are often used to escort other types of vessels (
e.g.,
tankers and bulk carriers) through ice-covered areas. Furthermore, new classes of ships are being designed that serve the dual roles of both tanker/carrier and icebreaker (Arctic Council 2009). Therefore, if icebreaking activities increase in the Arctic in the future, as expected, the likelihood of negative impacts (
e.g.,
habitat alteration and risk of oil spills) occurring in ice-covered areas where Arctic ringed seals reside will likely also increase. We are not aware of any data currently available on the effects of icebreaking on the habitat of Arctic ringed seals during the reproductive and molting periods. Although impacts of icebreaking are likely to vary between species depending on a variety of factors, Wilson
et al.
(2017) demonstrated the potential for impacts of icebreaking, which for Caspian seal (
Pusa caspica
) mothers and pups and their sea-ice-breeding habitat, included displacement, breakup of whelping and nursing habitat, and vessel collisions with mothers or pups. The authors noted that while pre-existing shipping channels were used by seals as artificial leads, which expanded access to whelping habitat, seals that whelp on the edge of such leads are vulnerable to vessel collision and repeated disturbance.
In addition to the potential effects of icebreaking on the essential features, the maritime shipping industry transports various types of petroleum products, both as fuel and cargo. In particular, if increased shipping involves the tanker transport of crude oil or oil products, there would be an increased risk of spills (Arctic Climate Impact Assessment 2005, U.S. Arctic Research Commission 2012). Similar to oil and gas activities, the most significant threat posed by shipping activities is considered to be the accidental or illegal discharge of oil or other toxic substances carried by ships (Arctic Council 2009).
Vessel discharges associated with normal operations, including sewage, grey water, and oily wastes are expected to increase as a result of increasing marine shipping and transportation in Arctic waters (Arctic Council 2009, Parks
et al.
2019), which could affect the primary prey of Arctic ringed seals. Increases in marine shipping and transportation and other vessel traffic is also introducing greater levels of underwater noise (Arctic Council 2009, Moore
et al.
2012), with the potential for behavioral and other effects in fishes and invertebrates (Slabbekoorn
et al.
2010, Hawkins and Popper 2017, Popper and Hawkins 2019), although there are substantial gaps in the understanding of such effects, in particular for invertebrates (Hawkins
et al.
2015, Hawkins and Popper 2017), and the nature of potential effects specifically on the primary prey of Arctic ringed seals are unclear.
We conclude that the essential features of the habitat of the Arctic ringed seal may require special management considerations or protection in the future to minimize the risks posed by potential shipping and transportation activities because: (1) Physical alteration of sea ice by icebreaking activities could reduce the quantity and/or quality of the sea ice essential features; (2) in the event of an oil spill, sea ice essential for birth lairs and/or for basking and molting could become oiled; and (3) the quantity and/or quality of the primary prey resources could be diminished as a result of spills, vessel discharges, and noise associated with shipping, transportation, and ice-breaking activities.
Commercial Fisheries
The specific area identified in this final rule as meeting the definition of critical habitat for the Arctic ringed seal overlaps with the Arctic Management Area and the Bering Sea and Aleutian Islands Management Area identified by the North Pacific Fishery Management Council. No commercial fishing is permitted within the Arctic Management Area due to insufficient data to support the sustainable management of a commercial fishery there. However, as additional information becomes available, commercial fishing may be allowed in this management area. Two of the primary Arctic ringed seal prey species identified as essential to the species' conservation—Arctic cod and saffron cod—have been identified as likely initial target species for commercial fishing in the Arctic Management Area in the future (North Pacific Fishery Management Council 2009).
In the northern portion of the Bering Sea and Aleutian Islands Management Area, commercial fisheries overlap with the southernmost portion of the critical habitat. Portions of the critical habitat also overlap with certain state commercial fisheries management areas. Commercial catches from waters in the critical habitat area primarily include: Pacific halibut (
Hippoglossus stenolepis
), several other flatfish species, Pacific cod (
Gadus macrocephalus
), several crab species, walleye pollock, and several salmon species.
Commercial fisheries may affect the primary prey resources identified as essential to the conservation of the Arctic ringed seal, through removal of prey biomass and potentially through modification of benthic habitat by fishing gear that contacts the seafloor. Given the potential changes in commercial fishing that may occur with the expected increasing length of the open-water season and distribution shifts of some economically valuable species responding to climate change (
e.g.,
Stevenson and Lauth 2019, Thorson
et al.
2019, Spies
et al.
2020), we conclude that the primary prey resources essential feature may require special management considerations or protection in the future to address potential adverse effects of commercial fishing on this feature.
Unoccupied Areas
Section 3(5)(A)(ii) of the ESA authorizes the designation of specific areas outside the geographical area occupied by the species, if those areas are determined to be essential for the conservation of the species. Our regulations at 50 CFR 424.12(b)(2) require that we first evaluate areas occupied by the species, and only consider unoccupied areas to be essential where a critical habitat designation limited to geographical areas occupied would be inadequate to ensure the conservation of the species. Because Arctic ringed seals are considered to occupy their entire historical range that falls within U.S. jurisdiction, we find that there are no unoccupied areas within U.S. jurisdiction that are essential to their conservation.
Application of ESA Section 4(a)(3)(B)(i)
Section 4(a)(3)(B)(i) of the ESA precludes designating as critical habitat any lands or other geographical areas owned or controlled by the Department of Defense (DOD), or designated for its use, that are subject to an Integrated Natural Resources Management Plan (INRMP) prepared under section 101 of the Sikes Act (16 U.S.C. 670a), if the Secretary determines in writing that such plan provides a benefit to the species for which critical habitat is proposed for designation.
See
16 U.S.C. 1533(a)(3)(B)(i); 50 CFR 424.12(h). Where these standards are met, the relevant area is ineligible for consideration as potential critical habitat. The regulations implementing the ESA set forth a number of factors to guide consideration of whether this standard is met, including the degree to which the plan will protect the habitat of the species (50 CFR 424.12(h)(4)). This process is separate and distinct from the analysis governed by section 4(b)(2) of the ESA, which directs us to consider the economic impact, the impact on national security, and any other relevant impact of designation, and affords the Secretary discretion to exclude particular areas if the benefits of exclusion outweigh the benefits of inclusion of such areas.
See
16 U.S.C. 1533(b)(2).
Before publication of the revised proposed rule (86 FR 1452, January 9, 2021), we contacted DOD (Air Force and Navy) and requested information on any facilities or managed areas that are subject to an INRMP and are located within areas that could potentially be designated as critical habitat for the Arctic ringed seal. In response to our request, the Air Force provided information regarding an INRMP addressing twelve radar sites, 10 of which (7 active and 3 inactive) are located adjacent to the area that was under consideration for designation as critical habitat: Barter Island Long Range Radar Site (LRRS), Cape Lisburne LRRS, Cape Romanzof LRRS, Kotzebue LRRS, Oliktok LRRS, Point Barrow LRRS, Tin City LRRS, Bullen Point Short Range Radar Site (SRRS), Point Lay LRRS, and Point Lonely SRRS. The Air Force requested exemption of these 10 radar sites pursuant to section 4(a)(3)(B)(i) of the ESA. Based on our review of the INRMP (draft 2020 update), the area we are designating as critical habitat, all of which occurs seaward of the 3-m isobath, does not overlap with DOD lands subject to this INRMP. Therefore, we conclude that there are no properties owned, controlled, or designated for use by DOD that are subject to ESA section 4(a)(3)(B)(i) for this critical habitat designation, and thus the exemptions requested by the Air Force are not necessary because no critical habitat would be designated in those radar sites.
Analysis of Impacts Under Section 4(b)(2) of the ESA
Section 4(b)(2) of the ESA requires the Secretary to designate critical habitat for threatened and endangered species on the basis of the best scientific data available after taking into consideration the economic impact, the impact on national security, and any other relevant impact, of specifying any particular area as critical habitat. Regulations at 50 CFR 424.19(b) also specify that the Secretary will consider the probable impacts of the designation at a scale that the Secretary determines to be appropriate, and that such impacts may be described qualitatively or quantitatively. The Secretary is also required to compare impacts with and without the designation (50 CFR 424.19(b)). In other words, we are required to assess the incremental impacts attributable to the critical habitat designation relative to a baseline that reflects existing regulatory impacts in the absence of the critical habitat.
Section 4(b)(2) also describes an optional process by which the Secretary may go beyond the mandatory consideration of impacts and weigh the benefits of excluding any particular area (that is, avoiding the economic, national security, or other relevant impacts) against the benefits of designating it (primarily, the conservation value of the area). If the Secretary concludes that the benefits of excluding particular areas outweigh the benefits of designation, the Secretary may exclude the particular area(s) so long as the Secretary concludes on the basis of the best scientific and commercial data available that the exclusion will not result in extinction of the species (16 U.S.C. 1533(b)(2)). We have adopted a policy setting out non-binding guidance explaining generally how we exercise our discretion under 4(b)(2).
See
Policy Regarding Implementation of Section 4(b)(2) of the Endangered Species Act (“4(b)(2) policy,” 81 FR 7226, February 11, 2016).
While section 3(5) of the ESA defines critical habitat as “specific areas,” section 4(b)(2) requires the agency to consider the impacts of designating any “particular area.” Depending on the biology of the species, the characteristics of its habitat, and the nature of the impacts of designation, “particular” areas may be—but need not necessarily be—delineated so that they are the same as the already identified “specific” areas of potential critical habitat. For the reasons set forth below, we exercised the discretion delegated to us by the Secretary to conduct an exclusion analysis based on national
security impacts with respect to a particular area north of the Beaufort Sea shelf that meets the definition of critical habitat for the Arctic ringed seal, and we exclude this area from the designation because we concluded that the benefits of exclusion outweigh the benefits of inclusion.
The primary impacts of a critical habitat designation arise from the ESA section 7(a)(2) requirement that Federal agencies ensure that their actions are not likely to result in the destruction or adverse modification of critical habitat (
i.e.,
adverse modification standard). Determining these impacts is complicated by the fact that section 7(a)(2) contains the overlapping requirement that Federal agencies ensure that their actions are not likely to jeopardize the species' continued existence. One incremental impact of critical habitat designation is the extent to which Federal agencies change their proposed actions to ensure they are not likely to adversely modify critical habitat, beyond any changes they would make to ensure actions are not likely to jeopardize the continued existence of the species. Additional impacts of critical habitat designation include any state and/or local protection that may be triggered as a direct result of designation (we did not identify any such impacts for this designation), and other benefits that may arise, such as education of the public regarding the importance of an area for species conservation.
In determining the impacts of designation, we focused on the incremental change in Federal agency actions as a result of critical habitat designation and the adverse modification standard (see
Ariz. Cattle Growers' Ass'n
v.
Salazar,
606 F.3d 1160, 1172-74 (9th Cir. 2010) (holding that USFWS permissibly attributed the economic impacts of protecting the northern spotted owl as part of the baseline and was not required to factor those impacts into the economic analysis of the effects of the critical habitat designation)). We analyzed the impacts of this designation based on a comparison of conditions with and without the designation of critical habitat for the Arctic ringed seal. The “without critical habitat” scenario represents the baseline for the analysis. It includes process requirements and habitat protections already extended to the Arctic ringed seal under its ESA listing and under other Federal, state, and local regulations. The “with critical habitat” scenario describes the incremental impacts associated specifically with the designation of critical habitat for the Arctic ringed seal.
Our analysis for this final rule is described in detail in the associated Final Impact Analysis Report. This analysis assesses the incremental costs and benefits that may arise due to the critical habitat designation, with economic costs estimated over the next 10 years. We chose the 10-year timeframe because it is lengthy enough to reflect the planning horizon for reasonably predicting future human activities, yet it is short enough to allow reasonable projections of changes in use patterns in an area, as well as of exogenous factors (
e.g.,
world supply and demand for petroleum, U.S. inflation rate trends) that may be influential. This timeframe is consistent with guidance provided in Office of Management and Budget (OMB) Circular A-4 (OMB 2003, 2011). We recognize that economic costs of the designation are likely to extend beyond the 10-year timeframe of the analysis, though we have no information indicating that such costs in subsequent years would be different from those projected for the first 10-year period. However, we could not monetize or quantify such costs, as forecasting potential future Federal actions that may require section 7 consultation regarding Arctic ringed seal critical habitat becomes increasingly speculative beyond the 10-year time window of the analysis.
Below, we summarize our analysis of the impacts of designating the specific area identified in this final rule as meeting the definition of critical habitat for the Arctic ringed seal. Additional detail is provided in the Final Impact Analysis Report prepared for this final rule.
Benefits of Designation
We expect that Arctic ringed seals will increasingly experience the ongoing loss of sea ice and changes in ocean conditions associated with climate change, and the significance of other habitat threats will likely increase as a result. As noted above, the primary benefit of a critical habitat designation—and the only regulatory consequence—stems from the ESA section 7(a)(2) requirement that all Federal agencies ensure that any actions authorized, funded, or carried out by such agencies are not likely to destroy or adversely modify the designated habitat. This benefit is in addition to the section 7(a)(2) requirement that all Federal agencies ensure that their actions are not likely to jeopardize listed species' continued existence. Another benefit of critical habitat designation is that it provides Federal agencies and the public specific notice of the areas and features essential to the conservation of the Arctic ringed seal, and the types of activities that may reduce the conservation value or otherwise affect the habitat. This information will consistently focus future ESA section 7 consultations on key habitat attributes. The designation of critical habitat can also inform Federal agencies regarding the habitat needs of Arctic ringed seals, which may facilitate using their authorities to support the conservation of this species pursuant to ESA section 7(a)(1), including to design proposed projects in ways that avoid, minimize, and/or mitigate adverse effects to critical habitat from the outset.
In addition, the critical habitat designation may result in indirect benefits, as discussed in detail in the Final Impact Analysis Report, including education and enhanced public awareness, which may help focus and contribute to conservation efforts for the Arctic ringed seal and its habitat. For example, by identifying areas and features essential to the conservation of the Arctic ringed seal, complementary protections may be developed under state or local regulations or voluntary conservation plans. These other forms of benefits may be economic in nature (whether market or non-market, consumptive, non-consumptive, or passive), educational, cultural, or sociological, or they may be expressed through enhanced or sustained ecological functioning of the species' habitat, which itself yields ancillary welfare benefits (
e.g.,
improved quality of life) to the region's human population. For example, because the critical habitat designation is expected to result in enhanced conservation of the Arctic ringed seal over time, residents of the region who value these seals, such as subsistence users, could experience indirect benefits by enjoying subsistence activities associated with this species. As another example, the geographic area identified as meeting the definition of critical habitat for the Arctic ringed seal overlaps substantially with the range of the polar bear in the United States, and the Arctic ringed seal is the primary prey species of the polar bear, so the designation may also enhance conservation of the polar bear, and in turn provide indirect benefits (
e.g.,
existence and option values). Indirect benefits may also be associated with enhanced habitat conditions for other co-occurring species, such as the Pacific walrus (
Odobenus rosmarus divergens
), the Beringia DPS bearded seal, and other seal species.
It is not presently feasible to monetize, or even quantify, each component part of the benefits accruing
from the designation of critical habitat for the Arctic ringed seal. Therefore, we augmented the quantitative measurements that are summarized here and discussed in detail in the Final Impact Analysis Report with qualitative and descriptive assessments, as provided for under 50 CFR 424.19(b) and in guidance set out in OMB Circular A-4. Although the best available information does not provide an estimate to monetize or quantify all of the incremental benefits of the critical habitat designation, we conclude that they are not inconsequential.
Economic Impacts
Direct economic costs of the critical habitat designation accrue primarily through implementation of section 7(a)(2) of the ESA in consultations with Federal agencies (“section 7 consultations”) to ensure that their proposed actions are not likely to destroy or adversely modify critical habitat. Those economic impacts may include both administrative costs and costs associated with project modifications. Based on the best scientific and commercial data available and our assessment of the record of section 7 consultations from 2013 to 2019 on activities that may have affected the essential features (relatively few relevant consultations were identified for the 3 years prior to when the Arctic ringed seal was listed under the ESA), as well as available information on planned activities, we have not identified any likely incremental economic impacts associated with project modifications that would be required solely to avoid impacts to Arctic ringed seal critical habitat. The critical habitat designation is not likely to result in more requested project modifications because our section 7 consultations on potential effects to Arctic ringed seals and our incidental take authorizations for Arctic activities under section 101(a) of the Marine Mammal Protection Act (MMPA) both typically address habitat-associated effects to the seals even in the absence of a critical habitat designation. This is not to say such project modifications could not occur in situations we are unable to predict at this time, but based on the best information available for the 10-year period of the analysis, it is likely that any project modifications necessary to avoid impacts to Arctic ringed seal critical habitat would also be necessary to avoid impacts to the species in section 7 consultations that would occur irrespective of this designation. As a result, the direct incremental costs of this critical habitat designation are expected to be limited to the additional administrative costs of considering Arctic ringed seal critical habitat in future section 7 consultations.
To identify the types of Federal activities that may affect critical habitat for the Arctic ringed seal, and therefore would be subject to the ESA section 7 adverse modification standard, we examined the record of section 7 consultations from 2013 to 2019. These activities include oil and gas related activities, dredge mining, navigation dredging, in-water construction, commercial fishing, oil spill response, and certain military activities. We projected the occurrence of these activities over the timeframe of the analysis (the next 10 years) using the best available information on planned activities and the frequency of recent consultations for particular activity types. Notably, all of the projected future Federal actions that may trigger an ESA section 7 consultation because of their potential to affect one or more of the essential habitat features also have the potential to affect Arctic ringed seals. In other words, none of the activities we identified would trigger a section 7 consultation solely on the basis of the critical habitat designation. We recognize there is inherent uncertainty involved in predicting future Federal actions that may affect the essential features of Arctic ringed seal critical habitat; however, we did not receive any new relevant information in response to our specific request for comments and information regarding the types of activities that are likely to be subject to section 7 consultation as a result of the designation that changed our projection of future Federal actions that may trigger consultation.
We expect that the majority of future ESA section 7 consultations analyzing potential effects on the essential habitat features will involve NMFS and BOEM authorizations and permitting of oil and gas related activities. In assessing costs associated with these consultations, we took a conservative approach by estimating that future section 7 consultations addressing these activities would be more complex than for other activities, and would therefore incur higher third-party (
i.e.,
applicant/permittee) incremental administrative costs per consultation to consider effects to Arctic ringed seal critical habitat (see Final Impact Analysis Report). These higher third-party costs may not be realized in all cases because the administrative effort required for a specific consultation depends on factors such as the location, timing, nature, and scope of the potential effects of the proposed action on the essential features. There is also considerable uncertainty regarding the timing and extent of future oil and gas exploration and development in Alaska's Outer Continental Shelf (OCS) waters, as indicated by Shell's 2015 withdrawal from exploratory drilling in the Chukchi Sea, BOEM's 2017-2022 OCS Oil and Gas Leasing Program, and the reinstatement of the 2016 withdrawal of the Chukchi Sea and most of the Beaufort Sea from consideration for oil and gas leasing in January 2021 (Executive Order (E.O.) 13990). Although NMFS completed formal consultations for oil and gas exploration activities in the Chukchi Sea in all but 2 years between 2006 and 2015, no such activities or related consultations with NMFS have occurred since that time.
As detailed in the Final Impact Analysis Report, the total incremental costs associated with the critical habitat designation over the next 10 years, in discounted present value terms, are estimated to be $714,000 at a 7 percent discount rate and $834,000 at a 3 percent discount rate, for an annualized cost of $95,000 at both a 7 percent and a 3 percent discount rate. About 83 percent of these incremental costs are expected to accrue from ESA section 7 consultations associated with oil and gas activities in the Chukchi and Beaufort seas and adjacent onshore areas.
We have concluded that the potential economic impacts associated with the critical habitat designation are modest both in absolute terms and relative to the level of economic activity expected to occur in the affected area, which is primarily associated with oil and gas activities that may occur in the Beaufort and Chukchi seas. As a result, and in light of the benefits of critical habitat designation discussed above and in the Final Impact Analysis Report, we are not exercising our discretion to further consider and weigh the benefits of excluding any particular area based on economic impacts against the benefits of designation.
National Security Impacts
Section 4(b)(2) of the ESA also requires consideration of national security impacts. As noted in the Application of ESA Section 4(a)(3)(B)(i) section above, before publication of our 2014 proposed rule, we contacted DOD regarding any potential military operations impacts of designating critical habitat for the Arctic ringed seal. In a letter dated June 3, 2013, the DOD Regional Environmental Coordinator indicated that no impacts on national security were foreseen from such a
designation. As a result, in that proposed rule we did not identify any direct impacts from the critical habitat designation on activities associated with national security.
Following publication of our 2014 proposed rule, by a letter dated April 17, 2015, DOD indicated that upon further review, it had identified national security concerns with the designation due to overlap of the proposed critical habitat with an area that is used by the U.S. Navy for training and testing activities. This area was described as waters north of Prudhoe Bay off the Beaufort Sea shelf between approximately 125 and 200 nm from shore, extending east to the Canadian border and seaward to the outer boundary of the U.S. EEZ. DOD requested that NMFS exclude this area from the critical habitat designation due to national security impacts, expressing the view that designation of this area will impact national security if training and testing activities are prohibited or severely degraded, as detailed in a comment letter from the Navy dated March 30, 2015. More recently, by letter dated March 17, 2020, the Navy reiterated its request for this exclusion due to national security impacts, but modified the description of the particular area to include waters off the Beaufort Sea shelf between approximately 100 and 200 nm from shore (noting that ice conditions have required the Navy to conduct some recent activities closer to shore). However, in developing this final rule, we followed up with the Navy regarding the location of this area. The Navy clarified that the description in its 2020 letter was outdated and inconsistent with the map included in the letter. The particular area the Navy intended to request be excluded from designation includes waters off the Beaufort Sea shelf between approximately 50 to 80 and 200 nm from shore.
The Navy indicated in its written communications that it conducts Arctic training and testing exercises, referred to by the Navy as Ice Exercises (ICEXs), on and below the sea ice within the particular area requested for exclusion. ICEXs and the accompanying base camps are established anywhere from 100 to 200 nm north of Prudhoe Bay, Alaska. These exercises are planned to occur every 2 years and typically last 25 to 45 days. ICEX camps include approximately 15 to 20 temporary shelters which support 30 to 65 personnel. Training and testing activities include: Submarine activities; submarine surfacing, in which submarines avoid pressure ridges and conduct surfacings in first year ice or in polynyas; aircraft operations; building of runways; and other on-ice activities. The Navy noted that ICEX activities alter the ice by creating holes to deploy training and testing equipment and surfacing submarines. The Navy explained that due to the need for stable ice, flights are conducted immediately prior to buildup of the ICEX camp to determine the final location.
The Navy also noted that the Office of Naval Research conducts research testing activities in the deep waters of the Beaufort Sea with acoustic sources and the use of icebreaking ships to deploy and retrieve these sources, which it plans to continue in the future, and expressed concern that the designation of critical habitat could impact these activities. The Navy indicated that it also conducts other training and testing activities in the Arctic region in support of gaining and maintaining military readiness in this region, and expects additional training and testing activities to occur in this region. The activities may be similar to those identified for ICEXs, and likely also would include vessel movements, icebreaking, and support transport by air and sea. Testing activities may include air platform/vehicle tests, missile testing, gunnery testing, and anti-submarine warfare tracking testing.
The Navy expressed the concern that the critical habitat may impact national security if training and testing activities are prohibited or are required to be mitigated (for the protection of critical habitat) to the point where training and testing value is severely degraded, or if the Navy is unable to access certain locations within the Arctic region. The Navy indicated that if the critical habitat designation maintains the same boundaries identified in our 2014 proposed designation, it does not foresee a way that its training and testing activities will be able to be conducted without significant impacts on those activities. The Navy indicated that due to the size of the area proposed in 2014 as critical habitat for the Arctic ringed seal and the uniqueness of Arctic conditions, the Navy would not be able to shift its training activities to other areas or to different times of the year.
In addition to the information provided by the Navy, by letter dated April 30, 2020, the Air Force provided information concerning its activities at radar sites located adjacent to the area under consideration for designation as critical habitat (relevant sites identified above in the Application of ESA Section 4(a)(3)(B)(i) section). The Air Force requested that we consider excluding critical habitat near these sites under section 4(b)(2) of the ESA due to impacts on national security. Although we do not exempt the radar sites pursuant to section 4(a)(3)(B)(i) of the ESA, as discussed above, here we consider whether to exclude critical habitat located adjacent to these sites under section 4(b)(2) based on national security impacts.
The Air Force noted that annual fuel and cargo resupply activities occur at these radar sites primarily in the summer and installation beaches are used for offload. The Air Force indicated that coastal operations at these installations are limited, and when barge operations occur, protective measures are implemented per the Polar Bear and Pacific Walrus Avoidance Plan (preliminary final 2020) associated with the INRMP in place for these sites. The Air Force discussed that it also conducts sampling and monitoring at these sites as part of the DOD's Installation Restoration Program, and conducts larger scale contaminant or debris removal in some years that can require active disturbance of the shoreline. Coastal barge operations are a feature of both monitoring and removal actions.
Federal agencies have an existing obligation to consult with NMFS under section 7(a)(2) of the ESA to ensure the activities they authorize, fund, or carry out are not likely to jeopardize the continued existence of the Arctic ringed seal, regardless of whether or where critical habitat is designated for the species. The specific area identified as meeting the definition of critical for Arctic ringed seals in this final rule includes marine habitat extending seaward from the 3-m isobath (relative to MLLW), rather than from the line of MLLW as we had proposed. Thus, waters adjacent to the radar sites identified by the Air Force overlap to lesser extent with this specific area. The activities described in the Air Force's exclusion request are localized and small in scale, and it is unlikely that modifications to these activities would be needed to address impacts to critical habitat beyond any modifications that may be necessary to address impacts to Arctic ringed seals. We therefore anticipate that the time and costs associated with consideration of the effects of future Air Force actions on Arctic ringed seal critical habitat under section 7(a)(2) of the ESA would be limited if any, and the consequences for the Air Force's activities, even if we do not exempt or exclude the requested areas from critical habitat designation, would be negligible.
As a result, and in light of the benefits of critical habitat designation discussed above and in the Final Impact Analysis Report, with respect to the Air Force's
request, we have concluded that the benefits of exclusion do not outweigh the benefits of designation and therefore we are not exercising our discretionary authority to exclude these particular areas pursuant to section 4(b)(2) of the ESA based on national security impacts. However, given the specific national security concerns identified by the Navy, below we provide an analysis of our decision to exercise our discretionary authority under section 4(b)(2) of the ESA to exclude the area requested by the Navy based on national security impacts.
Other Relevant Impacts
Finally, under ESA section 4(b)(2) we consider any other relevant impacts of critical habitat designation. For example, we may consider potential adverse effects on existing management or conservation plans that benefit listed species, and we may consider potential adverse effects on tribal lands or trust resources. In preparing this critical habitat designation, we have not identified any such management or conservation plans, tribal lands or resources, or anything else that would be adversely affected by the critical habitat designation. Some Alaska Native organizations and tribes have expressed concern that the critical habitat designation might restrict subsistence hunting of ringed seals or other marine mammals, such that important hunting areas should be considered for exclusion, but no restrictions on subsistence hunting are associated with this designation. Accordingly, we are not exercising our discretion to conduct an exclusion analysis pursuant to section 4(b)(2) of the ESA based on other relevant impacts.
Exclusion Based on National Security Impacts
In the revised proposed rule, we proposed to exclude an area north of the Beaufort Sea shelf that is used by the Navy for training and testing activities based on our finding that the benefits to national security of exclusion outweigh the benefits of designation. In developing this final rule, we followed up with the Navy regarding the location of this area. The Navy clarified that the spatial data it previously provided to NMFS to map the requested exclusion inadvertently contained outdated information that did not reflect the full southern extent of the particular area they intended to request be excluded from the designation, which includes waters about 50 nm south of the southern boundary of the proposed exclusion area east of 150° W longitude. In reference to the southern extent of the requested exclusion, the Navy explained that the camp location for recent ICEXs has been positioned to the south of the area we proposed to exclude from designation in the revised proposed rule. In addition, the Navy requested that the western boundary of the proposed exclusion be extended one degree west to account for research activities being conducted by the Office of Naval Research within this area.
Based on the written information provided by the Navy (summarized in the
National Security Impacts
section above), and clarifications provided through subsequent communications with the Navy regarding the southern and western boundaries of the particular area requested for exclusion, we evaluated whether there was a reasonably specific justification indicating that designating certain areas as critical habitat would have a probable incremental impact on national security. In accordance with our 4(b)(2) policy (81 FR 7226, February 11, 2016), when the Navy provides a reasonably specific justification, we will defer to its expert judgment as to: (1) Whether activities on its lands or waters, or its activities on other lands or waters, have national security or homeland-security implications; (2) the importance of those implications; and (3) the degree to which the cited implications would be adversely affected by the critical habitat designation. In conducting our review of this exclusions request under section 4(b)(2) of the ESA, we gave great weight to the Navy's national security concerns. To weigh the national security impacts against conservation benefits of a potential critical habitat designation, we considered the following: (1) The size of the area requested for exclusion compared with the total size of the specific area that meets the definition of critical habitat for the Arctic ringed seal; (2) the conservation value of the area requested for exclusion; (3) the possibility that the Navy's activities would affect the area requested for exclusions and trigger ESA section 7 consultations, and the likelihood that Navy activities would need to be modified to avoid adverse modification or destruction of critical habitat; and (4) the likelihood that other Federal actions may occur that would no longer be subject to the ESA's critical habitat provisions if the particular area were excluded from the designation.
The area requested for exclusion comprises approximately 18 percent of the marine habitat that meets the definition of critical habitat for the Arctic ringed seal, and approximately 60 percent of the portion of this marine habitat north of the Beaufort Sea shelf (north of the 200-m isobath). As noted by the Navy in its exclusion request, and as discussed above in the
Distribution and Habitat Use
and Specific Areas Containing the Essential Features sections, data currently available on ringed seal use of the requested exclusion area, particularly for the northernmost portion, are limited. As we discussed above (see Specific Areas Containing the Essential Features section), aerial surveys of ringed seals during the periods of reproduction and molting have been conducted for the most part over the continental shelf within about 25 to 40 km of the Alaska coast. However, incidental sightings of ringed seals were documented up to about 100 km north of the Beaufort Sea shelf during bowhead whale aerial surveys conducted during spring and early summer. Although we are not aware of any similar data for U.S. waters farther north, the trend toward areas of earlier spring ice retreat suggests that habitat areas closer to the northern boundary of the U.S. EEZ are likely to retain sea ice suitable for birth lairs and/or basking and molting longer than habitat areas further to the south. In addition, recent satellite telemetry data for ringed seals tagged on the Alaska coast show that during the open-water season, some of these seals made forays north of the Beaufort Sea shelf, including into the westernmost part of the area requested for exclusion (Crawford
et al.
2019, Quakenbush
et al.
2019, Quakenbush
et al.
2020, Von Duyke
et al.
2020; ADF&G and North Slope Borough, 2020, unpublished data). We note that the telemetry data for these seals are unlikely to fully reflect the distribution of this species in U.S. waters for a number of reasons. For example, as discussed by Citta
et al.
(2018), the distribution of telemetry locations for tagged ringed seals is influenced by the location and season of tagging. Thus, although the area requested for exclusion contains one or more of the essential features of the Arctic ringed seal's critical habitat, data are limited at this time to inform our assessment of the relative value of this area to the conservation of the species. Dive recorders indicated that foraging-type movements of some of these tagged seals occurred over both the continental shelf and north of the shelf, suggesting that both areas may be important to ringed seals during the open-water period. Observations of ringed seals near and beyond the outer boundary of the U.S. EEZ in the Arctic Ocean Basin were also documented by marine mammal observers during a research geophysical
survey conducted in the summer of 2010.
The testing and training activities described in the Navy's exclusion request are temporally limited, localized, and small in scale. Based on our analysis of past Navy activities in the area, we think it is unlikely that modifications to such activities would be required if the particular area is designated as critical habitat (beyond modifications necessary to avoid impacts to ringed seals). However, we defer to the Navy's assessment of the critical importance of these activities to national security and acknowledge that any possibility of modifications could have adverse impacts on activities important to national security. The Navy has an existing obligation to consult with NMFS under section 7(a)(2) of the ESA to ensure the activities it funds or carries out are not likely to jeopardize the continued existence of the Arctic ringed seal, regardless of whether or where critical habitat is designated for the species. Aside from the Navy's training and testing activities, we are aware of few other Federal actions that would be expected to affect the particular area requested for exclusion.
In the revised proposed rule, we found that the benefits of excluding the requested area due to national security impacts outweighed the benefits of designating this area as critical habitat for the Arctic ringed seal, and exclusion of the area is not expected to result in the extinction of the species. As discussed in the Summary of Comments and Responses section of this final rule, we received public comments that expressed opposition to the exclusion and requested that we reduce or better justify it. In response to public comments, we followed up with the Navy and requested any additional information the Navy could provide regarding the size of the area requested for exclusion and how the Navy's activities would be impacted by the critical habitat designation.
In its written response, the Navy explained that to conduct ICEXs, the ice floe must meet strict criteria to support a camp and runway, such as thickness, lack of pressure ridges for the runway portion, and adjacent first-year and second-year ice. The Navy stated that given the variable nature of Arctic sea ice suitable to support the establishment of ice camps, the Navy's ICEX program requires flexibility for the area within which an ice camp may be established, as a location cannot be selected until just before the start of ICEX. The Navy explained that once established ice camps drift long distances (for example, as much as 100 miles) due to ocean currents and that the requested exclusion area ensures that the ice camp always remains within the bounds of that area for the entirety of ICEX.
The Navy qualified that because it has not consulted with NMFS under section 7 on Arctic ringed seal critical habitat, and because Navy tactics, technologies, and training events evolve over time, any descriptions of probable impacts to military readiness of designating the area requested for exclusion are necessarily in part theoretical. The Navy explained that the specific requirements for Navy camps along with the ephemeral nature of ice floes significantly limits the physical space in which Navy activities may occur, even apart from avoiding impacts to critical habitat. The Navy stated that it is not inconceivable that a warming climate would further reduce available space suitable for the Navy's activities, and if site selection of the camp were further constrained
—i.e.,
if Navy had to avoid locations in which its activities could have adverse impacts on the sea ice essential features—a suitable location may not be found, and necessitate cancellation of an exercise, which would result in impacts to Navy readiness. The Navy also stated that if impacts to the critical habitat were determined to be unacceptable in a future section 7 consultation, it would not be possible to shift ICEX to a suitable area not designated as critical habitat given the proposed boundaries of the designation. The Navy emphasized that the area requested for exclusion is uniquely suited for Navy training and testing in direct support of the National Command Authority's National Security Strategy in the Arctic region.
With regard to Office of Naval Research activities for which the Navy requested the western boundary of the proposed exclusion be extended one degree west, the Navy explained that these research activities include the deployment of moored acoustic sources that transmit intermittently year-round for the purpose of developing capabilities of navigating gliders or unmanned vehicles that can observe effects of climate change. The Navy described that the deployment or recovery of equipment may involve the use of an icebreaking vessel, which may remove or break up sea ice suitable for ringed seal basking and molting or birth lairs. The Navy stated that because locations to deploy and recover research equipment are pre-selected and there is little flexibility, there is similarly little to no flexibility in conducting icebreaking activities. The Navy discussed that for this reason, if NMFS required modifications to these research activities in a future section 7 consultation to avoid impacts to the critical habitat—such as seasonal or spatial avoidance areas or not breaking ice which has certain conditions—it would have significant impact on these activities. The Navy stated that understanding changing Arctic conditions is critical for maintaining U.S. naval effectiveness and ensuring national security capabilities.
We recognize that there are limited data currently available to inform our evaluation of the conservation value to the Arctic ringed seal of the particular area requested for exclusion. However, we do not think this portion of ringed seal habitat contains features that are not found throughout the specific area designated as critical habitat, nor that exclusion would inhibit protection of the physical and biological features essential to the conservation of the species. Therefore, given the Navy's specific justification regarding potential impacts of the critical habitat designation on its military readiness activities that occur within the area requested for exclusion, we have concluded that the benefits of excluding this particular area due to national security impacts outweigh the benefits of designating this area as critical habitat for the Arctic ringed seal. Moreover, failure to designate this area as critical habitat is not expected to result in the extinction of the species because the area is small in comparison to the entirety of the area we are designating as critical habitat, we have no reason to believe it is more valuable for Arctic ringed seals than other portions of the critical habitat based on the best information currently available, and threats to Arctic ringed seals in this area (including habitat-related threats) from Federal actions will continue to be subject to section 7 consultations. In addition, few to no other Federal actions are anticipated to occur in this particular area that would no longer be subject to consultation regarding impacts to ringed seal critical habitat if this area is excluded. Consequently, we are excluding this area from the designation of critical habitat for the Arctic ringed seal, and we have adjusted the critical habitat boundaries accordingly. We modified the curvilinear southern boundary of the exclusion area recommended by the Navy to simplify its delineation while still including the full area the Navy recommended, resulting in a slightly larger excluded area (about 0.5 percent more area).
As explained in the Final Impact Analysis Report, the total incremental costs associated with designating the entire area identified as meeting the definition of critical habitat for the Arctic ringed seal over the next 10 years, in discounted present value terms, are estimated to be about $726,000 (discounted at 7 percent). The total incremental costs associated with the particular area excluded, which stem from administrative costs that would have been incurred from adding critical habitat analyses to consultations on the Navy's ICEX activities over the next 10 years, are estimated to be $12,000 (discounted at 7 percent).
Final Critical Habitat Designation
We are designating as critical habitat a specific area of marine habitat in Alaska and offshore Federal waters of the Bering, Chukchi, and Beaufort seas, within the geographical area presently occupied by the Arctic ringed seal. This critical habitat area contains physical or biological features essential to the conservation of Arctic ringed seals that may require special management considerations or protection. We exclude from the designation a particular area of marine habitat north of the Beaufort Sea shelf that is used by the Navy for training and testing activities based on our finding that the benefits to national security of exclusion outweigh the benefits of designation. We have not identified any unoccupied areas that are essential to the conservation of the Arctic ringed seal, and thus we are not designating any such areas as critical habitat. In accordance with our regulations regarding critical habitat designation (50 CFR 424.12(c)), the map we include in the regulation, clarified by the accompanying regulatory text, constitutes the official boundary of the critical habitat designation.
Effects of Critical Habitat Designation
Section 7(a)(2) of the ESA requires Federal agencies to ensure that any action authorized, funded, or carried out by the agency is not likely to jeopardize the continued existence of any threatened or endangered species or destroy or adversely modify designated critical habitat. Destruction or adverse modification means a direct or indirect alteration that appreciably diminishes the value of critical habitat as a whole for the conservation of a listed species (50 CFR 402.02). Federal agencies must consult with us on any agency action that may affect listed species or critical habitat. During interagency consultation, we evaluate the agency action to determine whether the action is likely to adversely affect listed species or critical habitat. The potential effects of a proposed action may depend on, among other factors, the specific timing and location of the action relative to the seasonal presence of essential features or seasonal use of critical habitat by listed species for essential life history functions. Although the requirement to consult on an action that may affect critical habitat applies regardless of the season, NMFS addresses spatial-temporal considerations when evaluating the potential impacts of a proposed action during the ESA section 7 consultation process. For example, if an action with short-term effects is proposed during a time of year that sea ice is not present, we may advise that consequences to critical habitat are unlikely. If we conclude in a biological opinion pursuant to section 7(a)(2) of the ESA that the agency action would likely result in the destruction or adverse modification of critical habitat, we would recommend one or more reasonable and prudent alternatives to the action that avoid that result.
Reasonable and prudent alternatives are defined in 50 CFR 402.02 as alternative actions identified during formal consultation that can be implemented in a manner consistent with the intended purpose of the action, that are consistent with the scope of the Federal agency's legal authority and jurisdiction, that are economically and technologically feasible, and that would avoid the destruction or adverse modification of critical habitat. NMFS may also provide with the biological opinion a statement containing discretionary conservation recommendations. Conservation recommendations are advisory and are not intended to carry any binding legal force.
Regulations at 50 CFR 402.16 require Federal agencies that have retained discretionary involvement or control over an action, or where such discretionary involvement or control is authorized by law, to reinitiate consultation on previously reviewed actions in instances where (among other reasons): (1) Critical habitat is subsequently designated; or (2) new information or changes to the action may result in effects to critical habitat not previously considered. Consequently, some Federal agencies may request reinitiation of consultation or conference with us on actions for which consultation has been completed if those actions may affect designated critical habitat for the Arctic ringed seal. Activities subject to the ESA section 7 consultation process include activities on Federal lands as well as activities requiring a permit or other authorization from a Federal agency (
e.g.,
a section 10(a)(1)(B) permit from NMFS), or some other Federal action, including funding (
e.g.,
Federal Highway Administration or Federal Emergency Management Agency funding). Consultation under section 7 of the ESA is not required for Federal actions that do not affect listed species or designated critical habitat, and is not required for actions on non-Federal and private lands that are not carried out, funded, or authorized by a Federal agency.
Activities That May Be Affected by Critical Habitat Designation
Section 4(b)(8) of the ESA requires, to the maximum extent practicable, in any regulation to designate critical habitat, an evaluation and brief description of those activities that may adversely modify such habitat or that may be affected by such designation. A variety of activities may affect Arctic ringed seal critical habitat and, if carried out, funded, or authorized by a Federal agency, may be subject to ESA section 7 consultation. Such activities include: In-water and coastal construction; activities that generate water pollution; dredging; commercial fishing; oil and gas exploration, development, and production; oil spill response; and certain military readiness activities. Section 7 consultations must be based on the best scientific and commercial information available, and outcomes are case-specific. Inclusion (or exclusion) from this list, therefore, does not predetermine the occurrence or outcome of any section 7 consultation. However, as explained above, based on our review of prior consultations in the area, we have not identified a circumstance in which project modifications would be necessary solely to avoid impacts to Arctic ringed seal critical habitat, as it is likely any such modifications would also be necessary to avoid impacts to the species.
Private or non-Federal entities may also be affected by the critical habitat designation if a Federal permit is required, Federal funding is received, or the entity is involved in or receives benefits from a Federal project. These activities would need to be evaluated with respect to their potential to destroy or adversely modify Arctic ringed seal critical habitat. For ongoing activities, this designation of critical habitat may trigger reinitiation of past consultations. Although we cannot predetermine the outcome of section 7 consultations, we do not anticipate at this time that the outcome of reinitiated consultations would likely require project
modifications because habitat-related effects on Arctic ringed seals would likely have been assessed in the original consultation. We are committed to working closely with other Federal agencies to conduct any reinitiated consultations in an efficient and streamlined manner to the maximum extent possible and consistent with our statutory and regulatory requirements.
Summary of Comments and Responses
We solicited comments on the revised proposed rule to designate critical habitat for Arctic ringed seals and the associated Draft Impact Analysis Report during a 90-day comment period and held three public hearings, as described above. We also contacted Federal, State, Tribal, and local agencies, and other interested parties by mail and invited them to comment on the revised proposed rule, and we issued news releases and published notices in local newspapers summarizing the revised proposed rule and inviting public comments. We received fifty unique written comment submissions and testimony from seven people during the public hearings.
In addition, we solicited peer review from three reviewers of our evaluation, interpretation, and use of available data regarding what areas meet the definition of critical habitat in the revised proposed rule. The peer reviewers generally agreed that we relied on the best available data regarding the Arctic ringed seal's habitat requirements and generally concurred with our application of this information in determining specific areas that meet the definition of critical habitat, except for some particular aspects that we address below in our responses to peer reviewer comments. We also solicited peer review from three reviewers of the information we considered in the Draft Impact Analysis Report for the proposed designation. The peer reviewers found the information considered in the Draft Impact Analysis Report to be thorough and analyzed using appropriate methods. Most of the peer reviewers provided additional information, clarifications, and suggestions to further inform and improve the analyses. Some peer reviewers provided comments of an editorial nature that noted minor errors in the revised proposed rule or Draft Impact Analysis Report and offered non-substantive but clarifying changes in wording. We have addressed these editorial comments in the final rule and the Final Impact Analysis Report, as appropriate. Because these editorial comments did not result in substantive changes to the final rule, we have not detailed them here. The peer reviewer comments are available online (see
Information Quality Act and Peer Review
section). A few peer reviewers volunteered comments related to aspects of the proposed designation that were outside the scope of the requested reviews. We address those comments below in our responses to public comments.
We have reviewed and fully considered all comments and significant new information received from peer reviewers and the public. Summaries of the substantive comments received and our responses are provided below. As some peer reviewer and public comments were similar, we have, in certain cases, combined the comments, and respond to both the peer reviewer and public comments in the
Peer Review Comments
section below. General comments that did not provide information pertinent to the revised proposed rule have been noted but are not addressed further here. We have not responded to comments or concerns outside the scope of this rulemaking, such as comments disagreeing with NMFS's prior decision to list the Arctic ringed seal as threatened under the ESA.
Peer Review Comments
Evaluation of Critical Habitat
Comment 1:
We received comments from the three peer reviewers and several other commenters related to our proposed delineation of the southern boundary of critical habitat. Two peer reviewers, as well as two other commenters, recommended that we identify winter-spring Bering Sea ice edge foraging habitat of subadults as an additional essential feature of Arctic ringed seal critical habitat and base the southern boundary of critical habitat on the position of the ice edge for March or April rather than May to include areas that contain this feature. These peer reviewers and commenters referred to information on the movement and dive behavior of tagged subadult ringed seals in the vicinity of the Bering Sea ice edge in winter and spring (Crawford
et al.
2012a, 2019). The peer reviewers further noted that the seasonal pattern of southern ice edge use by subadults is distinct from adults and discussed reasons why it may be important habitat to this age class, including for winter foraging. The third peer reviewer commented that our description of the findings of Crawford
et al.
(2012a) understated data showing that almost all tagged subadults (11 of 12) wintered in Bering Sea ice edge habitat (Crawford
et al.
2019). The peer reviewers and commenters stated that the first few years of life after seals are weaned are an important life history period for maintaining the population.
Response:
We thoroughly considered the information available on winter-spring use of Bering Sea ice edge habitat by subadult Arctic ringed seals. Regarding our description of the findings of Crawford
et al.
(2012a), our intent was not to downplay those data, but rather to explain our consideration of this information relative to our reasoning that the southern boundary of the specific area delineated for the sea ice essential features is also appropriate for defining the southern extent of where the primary prey resources essential feature occurs. We have clarified in the preamble to this final rule that almost all of the tagged subadult ringed seals monitored during the studies cited by the peer reviewer overwintered in Bering Sea ice edge habitat. The study by Crawford et al. (2012) provides information on certain aspects of winter-spring habitat in the Bering Sea used by tagged subadult ringed seals, such as distance to the southern ice edge, sea ice concentration, and water depth. However, there is insufficient information available at this time to identify what particular habitat characteristics are important determinants of subadult ringed seal use of such habitat, and to assess how those habitat characteristics provide for the species' life history requirements such that they are essential to the conservation of the Arctic ringed seal. We recognize that the survival of subadult ringed seals is important to the conservation of Arctic ringed seals and that subadults may select habitat differently than adults. However, the comments did not include any additional data or specific information to describe the physical or biological features that characterize this habitat, or to evaluate its importance to the conservation of the Arctic ringed seal, and we are not aware of any such data or information. Consequently, we have not identified ice edge habitat for overwintering subadults as an essential feature of Arctic ringed seal critical habitat. We note, however, that the ESA allows us to consider revising the critical habitat designation if, in the future, new information becomes available that indicates revision may be warranted. With regard to identification of critical habitat for the primary prey resources essential feature, see our response to Comment 31.
Comment 2:
One peer reviewer and several other commenters stated that because Arctic ringed seal whelping occurs from mid-March through April it would be more appropriate to base the southern boundary of critical habitat on
the position of the ice edge for March or April rather than for May. The commenters expressed concern that because ice conditions fluctuate, areas south of the proposed southern boundary may be important for ringed seal whelping in some years, with one commenter suggesting that the timing of life-cycle activities is changing, for example basking is sometimes observed before May, which they believe also supports designating critical habitat further south. Two commenters also noted that because the seals move with the ice as it contracts northward, the May ice edge is largely inhabited by the same seals that previously occupied the ice edge further south. In addition, a commenter stated that we should clarify our statement that the majority of the limited detections of pups during aerial surveys of the Bering Sea (conducted in 2012 and 2013) occurred in Norton Sound. The commenter also suggested that we seek additional records of ringed seals and pups in the Bering Sea from Outer Continental Shelf Assessment Program (OCSEAP) cruises and a bowhead whale survey conducted in 1979, and stated that the historical presence of whelping ringed seals on the Bering Sea ice front in April indicates that it served as suitable habitat; therefore, discounting April ice because of recent deterioration of the ice implies that the critical habitat will shrink continuously as the ice further diminishes. One commenter also stated that because it is important to account for the habitat needs of young Arctic ringed seals that require sea ice for molting beginning in mid-April, the southern boundary should be based on the position of ice edge for March. In contrast, the Marine Mammal Commission concurred with our use of the estimated position of the sea ice edge in May to delineate the southern boundary of critical habitat.
Response:
We understand the concern expressed by the peer reviewer and commenters. However, as we explained in the revised proposed rule and the Specific Areas Containing the Essential Features section of this final rule, in determining the southern boundary, we focused on delineating the southern extent of where the sea ice essential feature associated with birth lairs is found on a consistent basis. We relied on this essential feature in determining the southern boundary because peak molting (for adults) takes place later in the spring as sea ice retreats northward, and also because the annual extent and timing of sea ice is especially variable in the southern periphery of the Arctic ringed seal's habitat in the Bering Sea. Although April is the peak month for ringed seal whelping, snow-covered sea ice would need to persist for several weeks for pups to be sheltered and nursed in birth lairs. Taken as a whole, we continue to conclude that information available on the spring distribution of ringed seals in the Bering Sea suggests that the median position of the ice edge for May provides the best estimate of the southern extent of where the birth lair essential feature occurs on a consistent basis. We recognize that some ringed seals may use sea ice to whelp or molt south of the areas we are designating as critical habitat, depending upon ice conditions in a given year. However, as we stated in the revised proposed rule and this final rule, given the variability in the annual extent and timing of sea ice in this southernmost portion of the Arctic ringed seal's range in the Bering Sea, these waters are unlikely to contain the sea ice essential feature on a consistent basis in more than limited areas. This does not imply that habitat in the Bering Sea not included in the designation is unimportant to Arctic ringed seals, or may not support their conservation. Rather, the designation delineates the subset of habitat within the area occupied by the Arctic ringed seal in U.S. waters that meets the definition of critical habitat under the ESA based on the best scientific data currently available, and includes the majority of molting and reproductive habitat in the Bering Sea.
Regarding the comments concerning our statement in the revised proposed rule that the majority of ringed seal pups documented during aerial surveys were located in Norton Sound, as indicated above, this general spatial pattern was similarly reported in terms of pup densities in the recent publication by Lindsay
et al.
(2021), which we reference in this final rule. As for the comment concerning additional records of ringed seals and pups in the Bering Sea, the commenter did not provide any specific reference information, and we thoroughly considered all available evidence on the spring distribution of ringed seals in the Bering Sea and where they may whelp, including information from older OCSEAP and other surveys where references were readily available.
Comment 3:
One peer reviewer commented that quality of Arctic ringed seal whelping habitat under climate change could be further considered, in particular regarding what is considered the sufficient depth of snowdrifts for birth lairs. The peer reviewer stated that it could be surmised that pup survival is variably affected by a continuum of snow depths, and argued that there is insufficient information available to establish a specific threshold snowdrift depth for the birth lair essential feature. The peer reviewer pointed out that the few studies that have measured snow depths at birth lairs were completed several decades ago before the modern period of substantial declines in sea ice, and noted that because these studies were not designed to measure snow depth requirements for successful whelping, per se, they are not necessarily the best source for determining a specific threshold snowdrift depth for birth lairs. The peer reviewer also commented that snow accumulation on sea ice is affected by several factors that have dramatically changed in recent years, for example, late formation of sea ice in the fall limits snow accumulation that contributes to lair construction and maintenance; and suggested that in recent years, it is possible that somewhat marginal whelping habitat is already found in the Pacific Arctic region, in the Bering and Chukchi seas in particular. Another commenter stated that because ringed seals will necessarily be faced with decreasing snow for birth lairs, we should base the minimum snowdrift depth for birth lairs o
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