Pacific Sleeper Shark
Common Names: Pacific Sleeper Shark
Scientific Name: Somniosus pacificus
Size: Up to 4.4m
Found: Deepwater to at least 2000m in Northern Pacific Ocean. Japan, Mexico, Russian Federation, Taiwan, Taiwan, Province of China (main island), United States
Population Status: Data Deficient (IUCN 2013)
They have small mouths and long heads, which may suggest powerful suction feeding. Sleeper sharks feed upon a variety of surface and bottom animals, including salmon, rockfish, octopus, squid, crabs, and carrion. It is not known if some food items such as harbour seal are caught live or taken as carrion.
Viviparous (young are nourished by a yolk sac and are born live). Pregnant females have not yet been found, so information on pups is scarce. When young are born, they are 40-65cm in length.
Data from recent tagging studies in the Northeast Pacific showed some sleeper sharks regularly ascend and descend at rates over 200 meters per hour, traveling below the photic zone during the day and approaching the surface at night (Hulbert et al. 2006).
These sharks are caught as bycatch by bottom trawlers and deep-set longliners, sharks living below the depths of these activities may be safe from threat.