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  er/places/culture- places/food/iceland_rottensharkmeat.html er/places/culture- places/food/iceland_rottensharkmeat.html er/places/culture- places/food/iceland_rottensharkmeat.html  Zo Zo Zo  whabKr_r0 whabKr_r0 whabKr_r0  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),  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),  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,  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),  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),  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),