Do Pacific Sleeper Sharks Prey on Steller Sea Lions?
Steller sea lion abundance from Prince William Sound (PWS) westward has declined since at least 1965. The cause of the sea lion decline is unknown. The purpose of our study is to determine whether sleeper sharks, Somniosus pacificus, prey on Steller sea lions, and if they do, estimate the predation rate. Twenty-one long line sets were completed near four Steller sea lion rookeries in northeast GOA of Alaska in August 2001. Ninety-nine sleeper sharks were collected for sampling. Sleeper shark lengths ranged from 106- to 226-cm precaudal length (PCL), with most between 130- and 210-cm PCL. Sleeper shark weight ranged from 15 to 216 kg, with most between 30 and 90 kg. Of the 99 shark stomachs analyzed; 13 were empty, and 86 contained food. Walleye pollock was the most dominant identified prey, representing 16% by weight and 44% by frequency of occurrence. Cetacean tissue was the most important diet item (30% by weight), and octopus was the most frequently ocurring prey species (50%). Unid
