Steller sea lion

Eumetopias jubatus

SUBFAMILY

Otariinae

TAXONOMY

Eumetopias jubatus (Schreber, 1776), Commander and Bering Islands, Russia.

OTHER COMMON NAMES

English: Northern sea lion; French: Lion de mer de Steller; German: Stellers Seelöwe; Spanish: Lobo marine de Steller; Aleut: qawax; Russian: Sivuch.

PHYSICAL CHARACTERISTICS

This is the largest of the otariids. Males are reddish or dark brown to nearly white, average 1,248 lb (566 kg), and reach a maximum of 2,469 lb (1,120 kg). Females are tan, average 580 lb (263 kg), and reach a maximum of 772 lb (350 kg). Pups are chocolate, wooly, and weigh approximately 44 lb (20 kg) at birth.

DISTRIBUTION

Ocean from central California to the Kuril Islands. HABITAT

They breed on rock, sand, or cobble beaches from central California to the Kuril Islands with the population peak in the Aleutian chain. They breed on islands except at one site, a cave in Oregon. Where the ranges overlap, Steller sea lions have extensive contact with California sea lions and northern elephant seals. No hybrids are known.

BEHAVIOR

Males are territorial, and females form aggregations, often very dense because of their tendency to rest in full body contact with others. Females move to the water's edge in hot weather.

FEEDING ECOLOGY AND DIET

The species takes a wide variety of fish and cephalopods, including walleye pollock, cod, mackerel, flatfish, small schooling fish, salmon, and occasionally birds or other seals. Feeds at all hours of the day, often in groups.

REPRODUCTIVE BIOLOGY

Polygynous. They have a predictable annual breeding season. Most females wean young by one year of age, but a few return to breeding sites still suckling two to three year-old young.

CONSERVATION STATUS

Listed as Endangered. The species has been declining in California since the 1920s. Their overall numbers have declined by 90% since the 1980s, especially in the central Aleutian Islands. In 1994 a census revealed 100,000 animals, but the number may now be as low as 75,000.

SIGNIFICANCE TO HUMANS

The population decline may be linked to commercial fishing for walleye pollock, the largest single-species fishery in the United States. The legal, financial, and research implications of this possible impact are having significant effects on many aspects of human society at present. The species is declining in parallel with northern fur seals, harbor seals, and sea otters in Alaska. ♦

Common name / Scientific name/ Other common names

Physical characteristics

Habitat and behavior

Distribution

Diet

Conservation status

Subantarctic fur seal Arctocephalus tropicalis English: Amsterdam Island fur seal; French: Otarie subantarctique; German: Kerguelen-Seebär; Spanish: Oso marino de subantarctico

New Zealand fur seal Arctocephalus forsteri English: Antipodean fur seal, Western Australian fur seal; French: Otarie de Nouvelle-Zélande; German: Australischer Seebär, Neuseeland-Seebär; Spanish: Oso marino de Nueva Zelandia

Afro-Australian fur seal Arctocephalus pusillus French: Otarie d'Australie; German: Südafrikanischer Seebär Australischer Seebär; Spanish: Oso marino de Australia.

Only seal with white or yellowish hair on the face, neck, and chest. Dorsally, it is gray, like other fur seals. Males to 287 lb (130 kg); females to 79 lb (36 kg).

Both sexes gray in color

Males spend most of the year at sea, females stay relatively close to the rookeries. Breeding occurs on temperate coastal areas. Females have the longest known feeding absences of any otariid, which means their pups have very prolonged fasts.

Gathers in fairly small colonies at a large number of sites. Males are small and have fairly brief territorial tenure, resulting in a high turnover rate among males, and fairly frequent aggression. Females gather in groups, and may move to the water on hot days (Australia). Females make moderately long trips to sea.

Both sexes gray/brown. Largest species of fur A. p. pusillus breeds from seal. Males reach more than 551 lb (280 kg), Namibia to the Indian Ocean females 176 lb (80 kg). coast of southern Africa at several island sites, and at several mainland sites. The species feeds only on the continental shelf. A. p. doriferus breeds only in the Bass Strait region of southern Australia on a small number of sites near limited foraging grounds. Males are territorial, and females form dense groups that move to water and back, depending on solar radiation.

Juan Fernández fur seal Arctocephalus phlllpll French: Arctocéphale de Juan Fernandez; German: Juan-Fernandez Seebär; Spanish: Oso marino de Chile

Mostly gray. Males to 309 lb (140 kg); females to 106 lb (48 kg).

South American fur seal Arctocephalus australis French: Otarie d'Amérique du Sud; German: Südliche Pelzrobbe; Spanish: Oso marino austral.

Gray. Males to 441 lb (200 kg), females to 132 lb (60 kg). Considered to be the most primitive member of the genus.

Temperate islands north of the Antarctic Convergence, including the islands of Amsterdam, Crozet, Grough, Marion, Prince Edward, St. Paul, Tristan, and Macquarie.

Islands around New Zealand and the southern coast of Australia.

A. p. pusillus: coast of Namibia and the south and west coasts of South Africa; A. p. doriferus: islands in Victoria and Tasmania, all in the Bass Strait near Australia.

Females forage on the deep scattering layer, and may travel as far as 310 mi (500 km) from shore per trip; their prey is patchily distributed. Some males defend shoreline territories and perform free floating copulations. Female foraging trips are very long (average 12 days, maximum 21 days), which affects many aspects of the social system.

Some colonies are occupied all year long. Males are territorial: some are landlocked, some are along the waterline, and some are mostly aquatic. Females move low or high on the beach depending on solar radiation, and males attempt unsuccessfully to control them.

Females take myctophids and squid associated with the deep scattering layer, as well as some krill and penguins. They forage up to 310 mi (500 km) from land on a trip to sea.

Squid, octopus, and fish, and occasionally birds.

Not threatened

Not threatened

50% fish (surface, mid-water, and bottom species), 37% cephalopods, 13% crustaceans, plus six species of birds.

Not threatened

Robinson Crusoe Island as well as Alejandro Selkirk and Santa Clara Islands in the Juan Fernández group of islands off the Chilean coast.

Neotropical ocean coasts from the Peninsula Pacaranas in southern Peru, south around the cape and north to Rio Grande do Sul in southern Brazil.

80% myctophids, and about 20% squid associated with the deep scattering layer

Vulnerable

Weakfish, cutlassfish, anchoveta, anchovy, and cephalopods. In Peru the species takes mostly anchoveta.

Not threatened

[continued]

Common name /

Scientific name/

Physical

Habitat and

Conservation

Other common names

characteristics

behavior

Distribution

Diet

status

Galápagos fur seal

Both sexes are brownish. Smallest of the

The largest colonies are on

Limited to the Galápagos

Mostly myctophid and

Vulnerable

Arctocephalus galapagoensis

otiids. Males 154 lb (70 kg), females 77 lb

Isabella and Fernandina Islands.

Islands.

bathylagid fish associated

French: Arctocéphale des

(35 kg).

Animals are present in their

with the deep scattering

Galapagos; German: Galapagos

colonies all year. They forage in

layer, and switches to

Seebär; Spanish: Oso marino de las

upwelling plumes around the

sardine and Selene

Galápagos

islands, and do not emigrate

decllvlfrons during El Niño

during periodic El Niño events.

events. Feeding is depressed

The species has a very prolonged

during the full moon

breeding season. Females forage

because prey do not

at night and are on land in day

ascend to the surface at

time, seeking the water's edge

night under those

during high temperatures.

conditions.

Guadalupe fur seal

Both sexes are gray/brown. Males average

Breeds on the east coast of

The Pacific Coast, from

Females feed on fish and

Vulnerable

Arctocephalus townsendi

414 lb (188 kg), females average 110 lb

Guadalupe Island, Mexico. Lone

the northern Channel

cephalopods of the deep

English: Lower Californian fur seal;

(50 kg).

animals are occasionally seen as

Islands of California,

scattering layer, and may

French: Arctocéphale de

far north as northern California.

United States, south to

cover 1,240 mi (2,000 km)

Guadalupe, otarie á fourrure

Some animals breed inside lava

Cedros Island, Baja

on a trip to sea, resulting

d'amérique;

tubes that extend to the shore.

California, Mexico.

in long foraging trips.

German: Guadeloupe Seebär;

This habit of breeding in caves

Spanish: Oso marino de Guadalupe

may have protected the species

from being exterminated by

sealers in the nineteenth century.

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