The Steller sea lion (Eumetopias jubatus), also known as the northern sea lion and Steller's sea lion, is a near-threatened species of sea lion in the northern Pacific. It is the sole member of the genus Eumetopias and the largest of the eared seals (Otariidae) and is also the largest species of sea lion. Among pinnipeds, it is inferior in size only to the walrus and the two species of elephant seals. The species is named for the naturalist Georg Wilhelm Steller, who first described them in 1741. The Steller sea lion has attracted considerable attention in recent decades, owing to significant and largely unexplained declines in their numbers over an extensive portion of their northern range in Alaska.
This site contains full information about Steller Sea Lion Underwater.