Description 
The Steller Sea Lion is the biggest sea lion.  Sea lions are often confused with seals, from which they can be distinguished, among other ways, by the presence of external ear flaps.  The males of this species are noticeably larger than the females: adult females are 2.1 to 2.4 m long and weigh 200 to 300 kg, while adult males reach a length of 2.7 to 3.1 m and a weight of 400 to 800 kg, the biggest of them weighing nearly a tonne.  Mature males develop a light “mane” of coarse hair on their massive muscular necks and chests, from which they derive the name “sea lion”.  Pups weigh 16 to 23 kg at birth, the young males generally being heavier than the females.  Pups have a shiny, blackish-brown pelt.  Coloration of dry juveniles and adults is pale yellow to light tan, darkening on their underside and near their flippers: wet individuals are greyish white.

Canadian Distribution of the Steller Sea Lion (shown in red) 1,2 Distribution is approximate and not intended for legal use. 1Author: Canadian Wildlife Service, 2004 2Data Sources: The main source of information and data is the COSEWIC Status Report. In many cases additional data sources were used; a complete list will be available in the future.

Distribution and Population 
The Steller Sea Lion lives in the coastal waters of the North Pacific from southern California to the Bering Strait, and west and southwest along the coast of Asia to Japan.  Two populations are recognized in these waters: the Eastern population and the Western population.  The animals living in Canada are part of the Eastern population extending from southern California to southeastern Alaska, in the United States.  They are only present in British Columbia, where three main breeding areas are found.  The first is in the Scott Islands, off the northwestern tip of Vancouver Island.  The second breeding area is located at Cape St. James, off the coast of the southern Queen Charlotte Islands.  The third is offshore from the Banks Islands, in the northern portion of the continental coast.  In addition to these breeding sites, there are about 21 year-round haulout sites, and many irregularly used winter haulout sites.

Since the Steller Sea Lion first received protection in 1970, the size of the adult population has practically doubled.  In 2002, about 3,400 pups were born in British Columbia.  The total population of animals living in the coastal waters of British Columbia during the breeding season is between 18,400 and 19,700 individuals.  About 7,600 of them are apparently of breeding age.

Worldwide the Eastern population has grown in the past few years, contrary to the Western population.  In 2002, the Eastern population was estimated at about 45,000 individuals, nearly as large as the Western population.  The Western population accounted for 90 percent of the world Steller Sea Lion population between the 1950s and the 1970s.

Habitat 
The Steller Sea Lion mainly lives in the coastal waters of the North Pacific. Little is known of its aquatic lifestyle.  In general, most Steller Sea Lions seem to feed on the continental shelf and along its edge.  In summer, these animals generally are seen within 60 km of the coasts, in water less than 400 m deep, but they sometimes venture up to 200 km offshore.  The Steller Sea Lion is not considered a migratory species, but individuals may disperse up to a considerable distance from the breeding sites.  The animals regularly haul out year round and tend to form compact groups with practically no space between individuals.  The terrestrial sites frequented by sea lions are divided into three categories: 1) rookeries, which consist of isolated rocks where the animals gather from May to June to give birth, mate, and nurse their pups away from land predators such as wolves and bears; 2) year-round haulout sites, accessible sites generally occupied year round; 3) winter haulout sites, occupied irregularly outside the breeding season.

Biology 
At sea, Steller Sea Lions are found individually or in groups of a few animals.  During the mating season, they form dense colonies on solid land where the calls of the adults and the bleating of the newborn pups provide a constant din.  The most powerful males breed with several females.  Between the end of May and the beginning of July, the females return to their native rookery to give birth to a single pup, which they generally nurse for nearly a year, although nursing sometimes lasts up to three years.  The mothers stay on land with the pups for about one out of two days, each stay on land being followed by a day at sea to feed.  The newborns are precocious: they are capable of crawling from birth and learn how to swim at around four weeks of age.  One month after their birth, the mothers begin to move their pups to the neighbouring haulout sites, thus joining the non-breeding males and young females.  Although it is fairly difficult to estimate, it seems that the mortality rate for pups is fairly high.  The lifespan is about 14 years for males and 22 years for females.  In British Columbia, the Steller Sea Lion eats mainly schooling fish, such as herring, hake, sandlance, salmon and sardines.  Sometimes deepwater wish, such as rockfish, flounder and skate, as well as squid and octopus, make up a substantial part of the Steller Sea Lion’s diet.

Threats 
The threats to the Steller Sea Lion can be classified in two main categories. The first category covers human-induced factors such as hunting and killing.  For most of the 20th century, Steller Sea Lions were killed as part of programs to control predators of fish raised in British Columbia fish farms.  Other human-induced limiting factors include accidental entanglement in fishing gear or debris; catastrophic accidents such as oil spills, environmental contaminants like heavy metals which are harmful to health; and finally, the relocation of sea lion populations away from their critical habitats, or the degradation of these habitats.  The species is also subject to a second category of threats, natural this time, which include occasional decreases in the number of prey available, predation by killer whales and disease.

Protection 
The Steller Sea Lion is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

Management of marine mammals in Canadian waters is the Federal Government’s responsibility. Commercial hunting of all marine mammals, including the Steller Sea Lion, is prohibited in the Pacific Region.  After having suffered from many years of killing, Steller Sea Lions have been protected since 1970 by various regulations of the Fisheries Act applied by Fisheries and Oceans Canada.  Some animals however, have been killed under special permits. The Oceans Act, which came into force in 1996, protects the habitats of marine mammals.

Certain breeding grounds in British Columbia also benefit from additional protection: the Cape St. James rookery is protected under the Canada National Parks Act and the Scott Islands rookeries are part of a provincial ecological reserve.

Other Protection or Status 
Under the Endangered Species Act in the United States, the Eastern population (which encompasses the British Columbia populations) is designated as Threatened, and the Western population (found in the Gulf of Alaska, the Bering Sea, the Aleutian Islands and Russia) is designated as Endangered.