Guide to Steller sea lions

Posted: Sunday, May 13, 2001

Identification: Adults are light brown to blond and appear tan in the water. Two pinnipeds (eared seals) are common in Southeast Waters: harbor seals and Steller sea lions. Sea lions are much larger. Stellers are sometimes referred to as northern sea lions. California sea lions may range north to Southeast Alaska but they are black and about half the size of Steller sea lions.

Size: Male sea lions are about twice as big as females. Full-grown males average 9 feet long and weigh 1,500 pounds, while females are 7 feet long and 600 pounds. Pups are about 45 pounds at birth and about 3 feet long.

Life history: Sea lions may disperse widely outside the summer breeding season. Most return to the rookeries where they were born to breed.

Females give birth to only one pup a year. The pups are born between May and July after a gestation period of almost a full year. Mating typically takes place just a few weeks after a pup is born. The females breed with dominant males that establish and defend territories and harems. Sea lions are sexually mature at 3 to 7 years, and may live up to 30 years.

Food: Steller sea lions are opportunistic carnivores. They eat fish, squid and shrimp. The males fast while they are defending territories, for as long as two months.

Behavior: Sea lions are gregarious and gather on haulouts and rookeries, usually secluded rocky islands. Their vocalizations are growls, grumbles and roars but they do not bark. They may dive as deep as 600 feet. Steller sea lions are able to rotate their rear flippers forward for four-legged movement; they are far more agile and mobile on land than seals.

Range: Steller sea lions range along the North Pacific Rim from California to the Aleutian Islands to northern Japan. Two separate stocks are recognized in U.S. waters. Cape Suckling near Cordova defines the boundary between the eastern and western stocks.

Status: The population is stable in Southeast waters but threatened and declining in Western Alaska. About 30,000 animals make up the eastern stock, ranging from California to Southcentral Alaska. Surveys performed in 1996 counted 14,571 Steller sea lions in Southeast Alaska and another 15,000 were counted from California to British Columbia. These populations have increased slightly since the mid-1970s.

The western population is a different story. That population was estimated at 140,000 in the mid-1950s. That plummeted to 30,000 animals in 1990; by 1998 it dropped to about 20,000.

Trending this week:


© 2018. All Rights Reserved.  | Contact Us