Elasmobranchii (sharks and rays) > Squaliformes
(Bramble, sleeper and dogfish sharks) > Somniosidae
Etymology: Somniosus: Latin, somnus = sleep (Ref. 45335).
Environment / Climate / Range
Marine; brackish; benthopelagic; depth range 0 - 2200 m (Ref. 247), usually 200 - 600 m (Ref. 35388). Deep-water; 1°C - 12°C (Ref. 247), preferred 6°C (Ref. 107945); 83°N - 35°N, 95°W - 61°E
Length at first maturity / Size / Weight / Age
Maturity: Lm ?, range 244 - 427 cm
Max length : 730 cm TL male/unsexed; (Ref. 247); max. published weight: 775.0 kg (Ref. 4699)
soft rays: 0;
Vertebrae: 41 - 44. A gigantic, heavily-bodied dogfish shark with a moderately long, rounded snout and small, low dorsal fins; lower caudal lobe long; upper jaw with small single-cusped teeth and lower jaw with moderate-sized, bent-cusped, slicing teeth (Ref. 5578). Medium grey or brown in color, sometimes with transverse dark bands or small light spots (Ref. 5578).
Arctic and North Atlantic.
Found on continental and insular shelves and upper slopes down to at least 1,200 m (Ref. 247) and to as deep as 2,200 m (Ref. 55584). Epibenthic-pelagic (Ref. 58426). In the Arctic and boreal Atlantic, it occurs inshore in the intertidal and at the surface in shallow bays and river mouths during colder months, retreating to depths of 180-550 m when the temperature rises (Ref. 247). Feeds on pelagic and bottom fishes (herring, Atlantic salmon, Arctic char, capelin, redfish, sculpins, lumpfish, cod, haddock, Atlantic halibut, Greenland halibut and skates (Ref. 5951)), sharks and skates (Ref. 5578), seals and small cetaceans, sea birds, squids, crabs, amphipods, marine snails, brittle stars, sea urchins, and jellyfish (Ref. 247, 58240). Petromyzon marinus was reported to have been attached to S. microcephalus (Ref. 58185). Ovoviviparous (Ref. 205). Also utilized fresh and dried for human and sled-dog food (flesh is said to be toxic when fresh); eskimos also used the skin to make boots, and the sharp lower dental bands as knives for cutting hair (Ref. 247). A very sluggish shark (Ref. 28609).
Ovoviviparous (Ref. 247). Distinct pairing with embrace (Ref. 205).
Yano, K., J.D. Stevens and L.J.V. Compagno, 2004. A review of the systematics of the sleeper shark genus Somniosus with redescriptions of Somniosus (Somniosus) antarcticus and Somniosus (Rhinoscymnus) longus (Squaliformes: Somniosidae). Ichthyol. Res. 51:360-373. (Ref. 50224)
IUCN Red List Status (Ref. 96402)
CITES (Ref. 94142)
Threat to humans
Poisonous to eat (Ref. 4690)
Fisheries: minor commercial; gamefish: yes
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates of some properties based on models
Phylogenetic diversity index (Ref. 82805
= 0.5313 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00525 (0.00300 - 0.00918), b=3.17 (3.02 - 3.32), based on LWR estimates for this species & (Sub)family-body (Ref. 93245
Trophic Level (Ref. 69278
): 4.2 ±0.6 se; Based on diet studies.
Resilience (Ref. 69278
): Very Low, minimum population doubling time more than 14 years (Fec=10; assuming tm>10).
Vulnerability (Ref. 59153
): Very high vulnerability (90 of 100) .