Steller's Sea Lion is found on the North Pacific coasts. The countries included are Russia, Japan, Canada, and part of the United States. More specifically it is found from the sea of Japan at 43 degrees N, north to the Pacific rim at 66 degrees N, and then south down to the North American Pacific coast to San Miguel Island at 34 degrees N.

Biogeographic Regions: nearctic (Native ); palearctic (Native )

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Range includes coastal waters of the North Pacific Ocean from California and northern Honshu, Japan, and Korea, north to the Bering Strait (Kenyon and Rice 1961, Calkins and Pitcher 1983, Loughlin et al. 1984, Bigg 1988, Perlov 1991, Sea Lion Recovery Plan Team 1991, NMFS 2008). Breeding rookeries extend from the central Kuril Islands and the Okhotsk Sea in the west to Año Nuevo Island and (formerly) San Miguel Island, California, in the east (Loughlin et al. 1987; NMFS 1993, 2008). Most of the largest rookeries formerly were in the Gulf of Alaska and the Aleutian Islands (Loughlin et al. 1984), but with the decline in the western distinct population segment the largest rookeries are now in Southeast Alaska and British Columbia (NMFS 2008). Breeding colonies occur in Oregon and British Columbia but not in Washington (nonbreeding occurrences only, mainly October to April).

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

This species is the largest of five species of seals belonging to the family Otariidae (eared seals). It is characterized by a yellowish buff color, and a coat of short coarse hair that lacks a distinct undercoat. Sea lions have longer flippers than the true or earless seals. They are capable of rotating their hind flippers forward in order to have full use of all four limbs on land.

Steller's Sea Lions show remarkable sexual dimorphism. Males are much larger than females. The length of the average male is 282 centimeters, while the length of the average female is only 228 centimeters. The weight of the average male is 566 kilograms, while the weight of the average female is only 263 kilograms. Males also have extremely thick muscular necks and a mane of coarse long hair.

Newborn pups are about 100 centimeters long, weigh 16-23 kilograms, and have a thick, dark brown pelage that molts to lighter after six months. After 2-3 years their color changes again, this time to the adult color.

Range mass: 263 to 566 kg.

Length: 300 cm

Weight: 1000000 grams

This species differs from the California sea lion in larger adult size (California sea lion is about 250 cm and 400 kg at most), paler pelage, absence of a protruding crest on the forehead of adult males, and presence of a large diastema between the fourth and fifth upper postcanine teeth.

• Terrestrial
• Marine

Colder waters are more preferable than warm waters.

Aquatic Biomes: coastal

Habitat Type: Marine

Comments: Marine habitats include coastal waters near shore and over the continental slope; sometimes rivers are ascended in pursuit of prey. When not on land, the sea lions may congregate at nearshore traditional rafting sites, or move out to the edge of the continental shelf (Kajimura and Loughlin 1988, Sea Lion Recovery Plan Team 1991). While offshore, the sea lions are most often found within 35 km of shore (Kenyon and Rice 1961, Fiscus and Baines 1966, Fiscus et al. 1976, Bonnell et al. 1983) but may range out to several hundred kilometers offshore. The distance sea lions move offshore varies seasonally, with fewer animals being sighted at sea during the summer (Fiscus et al. 1976, Bonnell et al. 1983). Waters extending 0.9 km from rookeries (and major haulouts) were determined to be essential habitat by the Recovery Team (see NMFS 1993); these waters, plus an air zone extending 0.9 km above a rookery/major haulout and (in Alaska) a land zone extending 0.9 km landward from a rookery/major haulout are included in critical habitat designations.

The most commonly used terrestrial habitat types are rookeries and haulouts. Rookeries are areas where adults congregate for breeding and pupping. These habitats generally occur on beaches of remote islands with difficult access for humans and other mammalian predators (Sea Lion Recovery Plan Team 1991). The beaches can be sand, gravel, cobble, boulder, or bedrock. Female sea lions tend to select locations for pupping that are gently sloping and protected from waves (Sandegren 1970). Females often use the same pupping site in successive years and tend to breed in or near their natal colony (Calkins and Pitcher 1982). Rookery sites may be used as haulout sites during the nonbreeding season. Independent juveniles usually avoid rookeries (Gentry 1970, Sandegren 1970, Calkins and Pitcher 1983, Hoover 1988). From about two weeks after birth, the pups begin to spend increasing amounts of time in the intertidal areas and swimming near shore. Haulouts are areas used by adult sea lions during the nonbreeding season and by nonbreeding adults and subadults throughout the year (Sea Lion Recovery Plan Team 1991). Haulout locations include exposed rocks, reefs, beaches, jetties, breakwaters, navigational aids, floating docks, and sea ice. Selection of both rookery and haulout sites appears to depend on a number of factors including substrate type, degree of exposure to wind and waves, proximity to food resources, tradition of use, season, and the degree of human disturbance (Gentry 1970, Sandegren 1970, Calkins and Pitcher 1983, Hoover 1988, Johnson et al. 1989).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Steller sea lions are not known to make regular migrations, but they do move considerable distances (reviewd by NMFS 2008). For example, Raum-Suryan et al. (2002) analyzed resightings of 8,596 pups that were branded from 1975-1995 on rookeries in Alaska. Almost all resightings of young-of-the-year were within 500 km of the rookery where the pup was born, although subsequent observations documented movements of 11 month-old pups with their mothers of over 800 km. Juvenile animals were seen at much greater distances from their rookery of birth (up to 1,785 km). Sightings of adults were generally less than 500 km away from the natal rookery although adult males have since been seen over 1,000 km from the rookery where they held a territory (also their natal rookery). [Source: NMFS 2008]

Some individuals may move northward in the Bering Sea in fall and winter (Loughlin et al. 1987). In late summer and fall, individuals from northern breeding colonies migrate southward, while those (especially adult males) from southern breeding areas migrate northward.

Juveniles in the Gulf of Alaska tend to move away from their rookeries in the summer and cross the northern sections of the Gulf. In southeastern Alaska, the movement tends to occur as a shift from inside waters in winter to the outer coastal waters in the summer (Calkins and Pitcher 1982).

Females with dependent young feed relatively close to rookeries and haulouts because they must return at regular intervals to feed their offspring (NMFS 2008). In Alaska, females foraged within 50 km of rookeries in summer but ranged up to several hundred kilometers offshore in winter (Merrick and Loughlin 1997).

Dispersal of individuals from their natal rookeries may play a significant role in the metapopulation dynamics and recovery of this species. For example, new rookeries established recently in Southeast Alaska resulted at least in part from dispersal of individuals from the large Forrester Island rookery and from rookeries in the western distinct population segment (Calkins et al. 1999, Raum-Suryan et al. 2002, Pitcher et al. 2007; unpublished data from Alaska Department of Fish and Game and NMFS, cited by NMFS 2008).

Steller's Sea Lions are known to be true carnivores. They feed on both commercial and non-commercial fish, and also on cephalopods (octopus and squid). Commercially exploited walleye pollack is an important part of their diet. This selective diet is a major cause of the Sea Lions' diminishing population, due to competition with humans for this favorite.

Comments: Steller sea lions feed opportunistically on fishes (mainly demersal and off-bottom schooling species) and cephalopods; sometimes also on various other invertebrates (cnidarians, sand dollars, worms, shelled mollusks, crustaceans, etc.) and rarely on birds or small pinnipeds (though males at St. George Island kill and eat large numbers of northern fur seal pups in late summer and fall).

Bulls fast for 1-2 months during during breeding season.

Throughout the year, feeding may occur in the vicinity of rookeries or far (hundreds of kilometers) away, and in shallow or deep water, depending on the sex and age of the individual and the season.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 21 - 80

Comments: NMFS (2008) mapped approximately 65 breeding rookeries (sites where greater than 50 pups were born); 13 of these are in the eastern distinct population segment. There are several hundred haul-out sites (NMFS 1993).

100,000 - 1,000,000 individuals

Comments: In the late 1970s, total population estimates had remained stable at about 250,000-300,000 since the late 1950s, with breeders distributed among 51 rookeries, 60 percent of which included over 1,000 adults; 38 percent of the recorded population was at nonbreeding haul-out sites during the breeding season (Loughlin et al. 1984). Surveys at rookeries and haulout sites throughout Alaska and Russia in 1989, and estimates from counts conducted at other locations in recent years, provided the following minimum numbers of sea lions: Alaska (53,000); Washington, Oregon, California (4,000); British Columbia (6,000); Russia (3,000) (National Marine Fisheries Service 1990).

Based on 2004-2005 data (NMFS 2008), the total population size of the western distinct population segment (DPS) of Steller sea lions in Alaska was estimated to be approximately 45,000 animals. The 2005 population of Steller sea lions in Russia (part of the western DPS) is estimated to be about 16,000. The eastern DPS was estimated to number between 46,000 and 58,000 animals in 2002 (Pitcher et al. 2007).

Predators include orcas (killer whales) and sharks.

Comments: Activity occurs throughout the year. Most feeding apparently occurs mainly at night, though diurnal feeding also is likely. Females with small young apparently feed mainly at night.

Average lifespan

Sex: female

Status: wild: 30.0 years.

Average lifespan

Status: wild: 23.0 years.

Mating generally occurs in May. Males establish a harem of 3-20 females and a territory surrounding them. The pups from the preceding season are born from late May to early June. Shortly after giving birth, the female is impregnated again. Sixty to sixty seven percent of all females are impregnated every year. Implantation of the fertilized egg is delayed for three months giving Steller's Sea Lion a twelve month gestation period. The new pups are fed by their mother for a minimum of three months and sometimes up until the next pup is born. The pups are able to swim after one month, and can catch food after approximately three months. The age of maturity is 3-6 years for females, and 3-7 years for males. On average, females live 30 years. Males, subject to injury in violent encounters with other males, typically live only 18 years.

Average birth mass: 19000 g.

Average gestation period: 274 days.

Average number of offspring: 1.

Average age at sexual or reproductive maturity (male)

Sex: male: 2420 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 1780 days.

The life cycle includes several basic stages, minimally including recently born pups, dependent juveniles, independent juveniles and subadults, and adults.

Females give birth to single pups a few days after arriving at the rookery, late May to early July (mainly late June). Females mate with territorial males within 2 weeks of parturition; mating occurs June to mid-July. Implantation is delayed 3-4 months; total gestation period is about 1 year. Female stays with her pup for 3-13 days, then begins a series of 1-2-day feeding trips that extend over a period of several weeks, during which time the pup is left ashore. Young are weaned usually within 1 year in California; lactation usually lasts more than 1 year in Alaska. Females are sexually mature in 3-4 years (or up to 8 years); may breed into their early 20s (Mathisen et al. 1962, Pitcher and Calkins 1981); most adult females breed annually, though a high rate of reproductive failure results in a lower than 100 percent birth rate among adult females (estimated at 55-63 percent by Pitcher and Calkins 1981 and Calkins and Goodwin 1988). Males attain sexual maturity at 3-7 years old (Pitcher and Calkins 1981), but breeding (territorial) males typically are at least 7-8 years old (most often 9-13 years old in Alaska) (Thorsteinson and Lensink 1962, Loughlin et al. 1987, Raum-Suryan et al. 2002). Males may live up to around 20 years and females to around 30 years.

• 1996
  Endangered
• 1994
  Vulnerable
  (Groombridge 1994)

These animals are a threatened species. The Steller sea lion was placed on the Endangered Species list in 1990. The Western Alaskan population was reclassified as Endangered in April 1997. This is due to a number of causes. Thousands were once killed each year in the nets of fishermen in Alaska. Changes in fishing techniques and gear in 1984 reduced the number killed. An unknown number are shot each year during commercial fishing because this species is seen as a pest to the industry. The Steller Sea Lion eats a variety of commercial fish. The intense commercial fishing of pollock, a major food source, has decreased the Alaskan population from 175,000 animals in 1962 to 40,000 in 1992. They are also caught in plastic trash, which usually leads to death. This species is also hunted on a small scale for subsistence and for trade.

The Steller Sea Lion is protected in the United States and the Commonwealth of Independent States (CIS) is proposing to add the species to the "red" species list.

US Federal List: endangered

IUCN Red List of Threatened Species: endangered

Rounded Global Status Rank: G3 - Vulnerable

Reasons: Fairly large breeding range around the edge of the North Pacific; abundance declined greatly in the 1970s and 1980s, then declined at a lower rate in the 1990s, especially in the western segment of the range; subsequently the decline greatly decreased or ceased; population fluctuations may be related to competition with fisheries, environmental variability, toxic substances, predation by orcas (killer whales), or other factors, but further study is needed.

Canada

Rounded National Status Rank: N2B,N3N : N2B: Imperiled - Breeding, N3N: Vulnerable - Nonbreeding

United States

Rounded National Status Rank: N3 - Vulnerable

Global Short Term Trend: Relatively stable (=10% change)

Comments: Through the 1990s, the western distinct population segment (DPS) continued to decline. The western population showed an increase of approximately 3% per year between 2000 and 2004. This was the first recorded increase in the population since the 1970s. However, the most recent available data from incomplete non-pup surveys in 2006 and 2007 suggest that the overall trend for the western DPS, through 2007, is either stable or slightly declining. It is not known whether the changing trends in the western DPS are the result of management actions, natural changes in the ecosystem, or other factors. [Source: NMFS 2008]

The eastern DPS remains on an increasing trend (NMFS 2008). At least part of the increase reflects movement of individuals from the western DPS into the eastern DPS. For example, of the two most recently established rookeries in the eastern DPS, about 70 percent of the pups born on Graves Rock were from western DPS females, and about 45 percent of the pups born at White Sisters were from western DPS females (Gelatt et al. 2006, NMFS unpublished data, cited by NMFS 2008). Movement inferred from the genetics data has been confirmed by the sighting of western branded females with pups at Graves Rock and White Sisters (NMFS unpublished data, cited by NMFS 2008).

Global Long Term Trend: Decline of 30-70%

Comments: The western distinct population segment (DPS) of Steller sea lions decreased from an estimated 220,000-265,000 animals in the late 1970s to fewer than 50,000 in 2000. The decline began in the 1970s in the eastern Aleutian Islands (Braham et al. 1980), western Bering Sea/Kamchatka and the Kuril Islands. In Alaska, the decline spread and intensified east and west of the eastern Aleutians in the 1980s and persisted at a slower rate through 2000 (Sease et al. 2001). The 12 percent increase in numbers of nonpups counted in the Alaskan range of the western DPS between 2000 and 2004 was the first region-wide increase observed during more than two decades of systematic surveys. The observed increase, however, has not been spread evenly among all regions of Alaska. Increases were noted in the eastern and western Gulf of Alaska and in the eastern and central Aleutian Islands, while the decline persisted through 2004 in the central Gulf of Alaska and the western Aleutian Islands. [Source: NMFS 2008]

The eastern DPS has increased at approximately 3 percent per year since the late 1970s (Pitcher et al. 2007).

Degree of Threat: A : Very threatened throughout its range communities directly exploited or their composition and structure irreversibly threatened by man-made forces, including exotic species

Comments: Western distinct population segment (DPS): A threats assessment concluded that the following threats are relatively minor: (1) Alaska Native subsistence harvest, (2) illegal shooting, (3) entanglement in marine debris, (4) disease, and (5) disturbance from vessel traffic and scientific research. Considerable uncertainty remains about the following potential threats to the recovery of the western DPS (relative impacts in parenthesis): competition with fisheries (potentially high), environmental variability (potentially high), incidental take by fisheries (low), toxic substances (medium) and predation by killer whales (potentially high). Considerable uncertainty, controversy, and disagreement exist within the scientific and stakeholder communities with regard to the potential threat posed by killer whale predation. [Source: NMFS 2008]

Eastern DPS: No threats to continued recovery were identified by NMFS (2008) for the eastern DPS. Although several factors affecting the western DPS also affect the eastern DPS (e.g., environmental variability, killer whale predation, toxic substances, disturbance, shooting), these threats do not appear to be at a level sufficient to keep this population from continuing to recover, given the long term sustained growth of the population as a whole. However, concerns exist regarding global climate change and the potential for the southern part of the range (i.e., California) to be adversely affected. [Source: NMFS 2008]

Management Requirements: NMFS (2008) listed the following recent conservation actions that likely have benefited Steller sea lions: substantial reduction in disturbance of important rookeries and haulouts; substantial reduction in the incidental catch of Steller sea lions in commercial fishing operations, particularly the groundfish trawl fishery; significant efforts to reduce intentional take by prohibiting shooting at or near Steller sea lions; intensive research to better describe the threats to Steller sea lions and provide management with options for recovery actions; potential reduction in the competitive interactions between Steller sea lions and commercial fisheries for pollock, Atka mackerel, and Pacific cod in Alaska; acquired additional information on the status, foraging ecology, and survivorship of Steller sea lions.

Management Research Needs: Research is needed on key threats potentially impeding sea lion recovery (NMFS 2008).

An adaptive management program to evaluate fishery conservation measures should be designed and implemented (NMFS 2008).

Global Protection: Many to very many (13 to >40) occurrences appropriately protected and managed

Comments: The Steller sea lion is protected in U.S. waters under the Marine Mammal Protection Act of 1972 and the Endangered Species Act of 1973. Specific protection measures include prohibition of shooting near sea lions, establishment of buffer zones to exclude marine vessels near rookeries and haulouts, and set quotas on allowable incidental kills (National Marine Fisheries Service 1990a, 1990b). Traditional subsistence take of Steller sea lions by Alaska natives is not prohibited by either of these Acts. In Canada, the Steller sea lion is protected under the Canadian Federal Fisheries Act of 1970 (Bigg 1988). This protection includes prohibition of disturbance, molestation, or killing of sea lions. Approximately 40 permits have been allotted to aquaculture facilities in southcoastal British Columbia to take sea lions habitually destroying their crops. In Russia, Steller sea lions are proposed for listing in the Red Book of threatened and endangered species (Laughlin, pers. comm., 1992). Also, no-entry buffer protection zones have been placed around the Commander and Kuril islands. There is no official protection for sea lions in Japan and males are harvested on the island of Haikado (Laughlin, pers. comm., 1992). See NMFS (1993) for listings and maps of areas included in designated critical habitat in Alaska, Oregon, and California. NMFS has implemented protective measures to reduce the effects of certain commercial groundfish fisheries near important sea lion rookeries and haulouts (Federal Register, 22 January 1999). NMFS and other agencies are implementing the recovery plan.

Needs: Current fishery conservation measures (or equivalent) should be maintained until substantive evidence demonstrates that these measures can be reduced without limiting recovery. (NMFS 2008).

Eats many commercial fish that humans exploit.

Profit from meat, hides, and blubber. Ecotourism benefits greatly from sea lions because humans think that they are "cute".

They are a primary source of food for inhabitants of the Aleutian Islands. Their skins can be used for boat coverings, clothing, and their whiskers for cleaning of Chinese opium pipes. Since the passage of the Marine Mammal Protection Act (1972), the use of these sea lions has declined.

Comments: Steller sea lion sometimes is viewed as a nuisance due to presumed economic impact on fisheries.

Historically this species was used for food, clothing, boat coverings, meat for fox farms, and craftwork. Current subsistence take (a couple hundred per year in Alaska in the early 2000s) for food, clothing, and craftwork is subject to federal management (in the United States) and is not regarded as contributing to population declines.

Stewardship Overview: The recovery plan (NMFS 2008) identified 78 substantive actions needed to achieve recovery of the western DPS by addressing the broad range of threats. These actions address three main objectives: (1) the collection of information on status and vital rates, (2) research programs to collect information on the remaining threats to recovery, including natural and anthropogenic factors, and (3) the implementation of conservation measures to remove impacts of anthropogenic threats to recovery. The recovery plan highlighted four actions believed to be especially important to the recovery program for the western DPS: (1) continue population monitoring and research on the key threats potentially impeding sea lion recovery; (2) maintain current or equivalent level of fishery conservation measures; (3) design and implement an adaptive management program to evaluate fishery conservation; and (4) develop an implementation plan. See NMFS (2008) for further details.

Comments: No controversy exists regarding the taxonomic status of this species. Research has focused on identifying patterns of genetic variation within the species. Some of this research is summarized here.

MtDNA data of Bickham et al. (1996) indicated the existence of two genetically differentiated populations of E. jubatus, one in the Commander Islands in Russia and the Aleutian Islands and Gulf of Alaska in Alaska, the other including samples from southeastern Alaska and Oregon; the populations do not trace their ancestries back to a single maternal ancestor in either case; they likely diverged as a result of separation in different glacial refugia. The authors stated that the two populations "likely should be managed separately."

Trujillo et al. (2004) studied genetic variation at 6 nuclear microsatellite loci with biparental inheritance and the maternally inherited mitochondrial DNA (mtDNA) at 3 geographic scales (rookeries, regions, and stocks). Population structure was not well defined, and there was no obvious phylogeographic pattern to the distribution of microsatellite alleles. This contrasts with the clear phylogeographic pattern revealed by control-region sequences of mtDNA in which 2 well-differentiated stocks, eastern and western, were defined as well as 2 distinct groups, Asian and central, in the western stock. Trujillo et al. (2004) stated that the difference in patterns between the biparentally and maternally inherited genetic markers can be explained by relatively high male dispersal rates and female philopatry, or else there has been insufficient time since populations have been isolated for the nuclear loci to have diverged. Trujillo et al. (2004) recommended that the presently accepted stock structure be retained for management purposes and that further studies be carried out to test the male dispersal hypothesis.

Harlin-Cognato et al. (2006) examined Steller sea lion phylogeography using range-wide mtDNA data and found that the pattern of diversification of female lineages appears to correlate with the glacial advances and retreats during the Pleistocene, from approximately 60,000 to 180,000 years ago. Four populations, ostensibly derived from distinct glacial refugia, were recognized, including continental North America, Gulf of Alaska and mainland Alaska, Aleutian Islands, and Eurasia.

Recent research indicates that the geographic boundary between the western and eastern populations may be changing or possibly disappearing (Pitcher et al. 2007; NMFS unpublished data, cited by NMFS 2008).

The English name for sea lions has been inconsistently rendered as sea lion, sealion, and sea-lion (Rice 1998; Wozencraft, in Wilson and Reeder 2005).