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SLEEPER SHARKS Family somniosidae Classification Kingdom animalia Phylum chordata Class chondrichthyes Order squaliformes Family somniosidae 7 genera 18 species Characteristics of the family 2 small dorsal fins, no spines Small pectoral fins Short, broad caudal fin No anal fins Small eyes Small upper spike like teeth Small lower teeth tightly overlapped Good for cutting Slate gray to brown and some with spots Family name derivation Somniosidae = “sleep” Know to be sluggish but can have bursts of speed to catch fast moving prey Most familiar species From genus Somniosus Somniosus pacificus- pacific sleeper shark Somniosus microcephalus- greenland shark Others include little sleeper, and different kinds of dogfish Pacific Sleeper Pacific Sleeper Shark Greenland Shark Greenland shark Greenland Shark Greenland teeth Size of sleepers Small to over 7m Size variable at different depths for S. pacificus larger at deeper depths for S. microcephalus ~ 40cm at birth Habitat of pacific sleeper Live in the Artic, and North Pacific Cold water -1-12C At lower latitudes = live deeper epibenthic High latitudes= live shallower; even intertidal Can be found up to 2000m deep Habitat of Greenland shark Arctic North Atlantic Found up to 2200 m deep epibenthic Food habits of Pacific sleeper Eat cephalopods, teleosts, crustaceans, marine mammals (cetaceans) Thought responsible for decline of stellar sea lion but found untrue Feed on bottom but are known to travel vertically and feed on pelagic fast moving prey Known to be sluggish but with quick bursts of energy Food habits of Greenland sharks Feed on gastropods, cephalopods, echinoderms, elasmobranchs, teleosts, marine mammals ( pinnipeds) Smaller (<200cm) mostly cephalopods Reproduction of sleepers Ovoviviparous 2 equally developed ovaries with pleats Males and females mature at ~400 cm 5-10 young at a time 40 cm at birth Gestation ~ 2years Special adaptations of sleepers Live in cold deep water Liver oil contains no squalene Instead have “DAGE” and “TAG” Acts as “antifreeze” Besides urea also produce trimethylamine oxide (TMAO) Stabilizes proteins against crushing pressure and cold People eat rotten meat of Greenland sharks said to taste like ammonia Parasites of sleepers Both S. microcephalus and S. pacificus have been found to contain copepod parasites, Ommatokoita elongata,on their eyes Causes lesions and thickening of the cornea Thought to affect image formation Have ability to detect light Rely on other senses Parasite copepod on eye videos http://video.nationalgeographic.com/video/play er/places/culture- places/food/iceland_rottensharkmeat.html http://www.youtube.com/watch?v=NPEi_L0hG Zo http://www.youtube.com/watch?v=B- whabKr_r0 http://www.youtube.com/watch?v=LJm7PwhrL NQ Literature cited Benz, GW; Borucinska, JD; Lowry, LF; Whiteley, HE ( 2002). Ocular lesions associated with attachment of the copepod Ommatokoita elongata (Lernaeopodidae : Siphonostomatoida) to corneas of Pacific sleeper sharks Somniosus pacificus captured off Alaska in Prince William Sound JOURNAL OF PARASITOLOGY. 88 (3), 474-481. Benz, GW; Lucas, Z; Lowry, LF (1998). New host and ocean records for the copepod Ommatokoita elongata (Siphonostomatoida : Lernaeopodidae), a parasite of the eyes of sleeper sharks. JOURNAL OF PARASITOLOGY. 84 (6), 1271-1274 . Frid, A; Baker, GG; Dill, LM. (2006) Do resource declines increase predation rates on North Pacific harbor seals? A behavior-based plausibility model. MARINE ECOLOGY-PROGRESS SERIES. 312, 265- 275. Hulbert, LB (Hulbert, L. B.); Sigler, MF (Sigler, M. F.); Lunsford, CR (Lunsford, C. R.). (2006). Depth and movement behaviour of the Pacific sleeper shark in the north-east Pacific Ocean. JOURNAL OF FISH BIOLOGY. 69 (2), 406-425. Sigler, MF (Sigler, M. F.); Hulbert, LB (Hulbert, L. B.); Lunsford, CR (Lunsford, C. R.); Thompson, NH (Thompson, N. H.); Burek, K (Burek, K.); O'Corry-Crowe, G (O'Corry-Crowe, G.); Hirons, AC (Hirons, A. C.). (2006) Diet of Pacific sleeper shark, a potential Steller sea lion predator, in the north-east Pacific Ocean. JOURNAL OF FISH BIOLOGY. 69 (2), 392-405. Yano, K (Yano, K.); Stevens, JD (Stevens, J. D.); Compagno, LJV (Compagno, L. J. V.). (2007) Distribution, reproduction and feeding of the Greenland shark Somniosus (Somniosus) microcephalus, with notes on two other sleeper sharks, Somniosus (Somniosus) pacificus and Somniosus (Somniosus) antarcticus. JOURNAL OF FISH BIOLOGY. 70 (2), 374-390.
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