Family: Steller sea lions are the largest of the otariids and the fourth largest of the pinnipeds, meaning “feather” or “fin” footed.

Lifespan: The average lifespan of a Steller sea lion is about 20 to 23 years although females may live up to 30 years.

Length and weight: The average adult male Steller sea lion is 9 feet in length and 1500 lbs. The average adult female is 7 feet in length and 600 lbs. At birth, Steller sea lions weigh 45 lbs. and are 3 feet in length.

Color: Adult Steller sea lions are light brown to blond with a dark brown darkening around the flippers and undersides. Steller sea lion pups are dark brown at birth. Unlike most pinnipeds, when wet or in the water, Steller sea lions appear light grayish-tan.

Behavior: Steller sea lions are generally aggressive and very vocal with grumbles, growls, and roars. Roaring males often bob their heads up and down when vocalizing. Adult males establish territories and aggressively defend them. Steller sea lions gather on haulouts and rookeries and regularly travel great distances (up to 250 miles) to find food. Diving is generally to depths of 600 feet or less and diving duration is usually 2 minutes or less.

Body: Steller sea lions have large, bulging eyes, and flat, square noses. Steller sea lions also have long whiskers which are used to navigate underwater and find prey. The ears of a Steller sea lion are visible and are turned downwards so that water does not enter them when the sea lions go underwater. When adult males age, they develop a “mane” of long, coarse hair. Steller sea lions are particularly agile on land and swim using their foreflippers.

Habitat: Steller sea lions inhabit the cool coastal waters of the North Pacific. When not in the water, Steller sea lions gather on rookeries and haulouts which are secluded rocky islands.

Food habits: Steller sea lions are opportunistic and eat a wide range of fish including herring, pollock, salmon, cod and rockfishes, as well as squid and shrimp. To survive, an adult sea lion needs to eat at least 6% of its body weight each day. Interestingly enough, Steller sea lions do not need to drink water because the food they eat provides them with all the water they need. Sea lions do not chew their food, most is swallowed whole. Feeding occurs in groups and at night between 9 PM and 6 AM.

Life History: Steller sea lions become sexually mature at 3 to 7 years of age and mate and give birth on land. Males usually arrive at a rookery in May and stake out their territories for up to 60 days. Females arrive later and usually give birth to a pup that was conceived the prior year. A pregnancy lasts about 11 ½ months and lactation continues for 1 to 3 years. Mating occurs shortly after the pups are born, during June and July.

Predators: Include humans, sharks, and killer whales.

Population Status: Two stocks are recognized for Steller sea lions - an Eastern Stock and a Western Stock. Under the ESA, they are considered "Distinct Population Segments" or DPS. The Eastern DPS is listed as "threatened", and the Western DPS is listed as "endangered".

Population Trend: The Eastern DPS has increased on average 3% per
year since the 1970's and has more than doubled in size in Southeast Alaska, British Columbia and Oregon.

The Western DPS trend is believed to have been be generally stable from 2004 to 2008. Within the Western DPS, differing trends have been seen in differing subregions.

For more information, the memo for the record on the 2009 surveys (pups statewide and non-pups for the Eastern Gulf) can be found at http://www.afsc.noaa.gov/nmml/PDF/SSL-Survey-09-memo-11-30-09.pdf

The 2008 memo for the record on the non-pup surveys can be found at: http://www.afsc.noaa.gov/nmml/pdf/SSLNon-Pups2008memo.pdf

STELLER SEA LION LINKS:
· NOAA Fisheries Alaska Region and Alaska Fisheries Science Center Steller Sea Lions Website
· North Pacific Universities Marine Mammal Research Consortium

7 February 2010