Pacific Sleeper Shark

Diagnosis: Somniosus pacificus differs from S. antarcticus by the following characters: interdorsal space about 70% of prebranchial length (vs. 80%); height of first dorsal fin about 3.7% of precaudal length (PCL) (vs. 3.0%); height of second dorsal fin about 3.4% of PCL (vs. 2.9%); number of turns in spiral valve 32-37 (mode 33) (vs. 36-41, mode 39); precaudal vertebrae 28-30 (mode 29) (vs. 30-31, mode 30) (Ref. 50224).Description: Uniformly greyish-pink with bluish black fins; live specimens probably with white spots on dorsal surface (Ref. 6871). Short rounded snout, heavily cylindrical body and small precaudal fins, equal-sized dorsal fins, asymmetrical caudal fin with a well-developed ventral lobe (Ref. 6871), first dorsal fin on back closer to pelvic fins than pectoral fins, interdorsal space less than distance from snout tip to first gill openings, no short keels on base of caudal fin, upper teeth lanceolate, lower teeth with short, low, strongly oblique cusps and high narrow roots (Ref. 247).

Probably ovoviviparous (Ref. 247). Size at birth 42 cm or less (Ref. 26346). Distinct pairing with embrace (Ref. 205).

Dorsal spines (total): 0; Analspines: 0; Analsoft rays: 0

Found on the continental slope (Ref. 75154).

Demersal and mesobenthopelagic (Ref. 119696); found on continental shelves and slopes (Ref. 247). At high latitudes, occasionally occurs in littoral and even intertidal areas; in lower latitudes it may never come to the surface and ranges down to at least 2,000 m (Ref. 247), reported to about 2,205 m in the Hawaiian Is. as recorded by camera arrays (Ref. 119696). Feeds on bottom animals such as fishes, octopi, squids, crabs and tritons; also harbor seals and carrion (Ref. 247). Ovoviviparous (Ref. 205), with 300 pups in a litter (Ref. 247), length at birth about 42 cm or less (Ref. 26346). The flesh contains a type of toxin which, when eaten, produces symptoms of drunkenness (Ref. 583). Possibly reaches lengths greater than 700 cm (Ref. 247).

fisheries: of no interest