To see photographs of the Bluntnose Sixgill (Hexanchus
griseus) click here.
Bluntnose Sixgill Shark (Hexanchus griseus)
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protected: © 2002 Kelvin Aitken.
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only. Not for commercial use.
Family: Hexanchidae. Sixgill & Sevengill Sharks. Cow Sharks.
Taxonomic name: Hexanchus griseus
Other Common Names: Sixgill Shark. Bull Shark.
A stocky body with a large caudal fin with long upper lobe. Sharp nose in profile but broadly rounded from above or below. No distinctive markings.
The mouth is large, beginning under the head below the eye, extending well back towards the gills, able to open very wide to take in large sized or large chunks of food. The lower teeth, like all six and seven gill sharks, resemble a hand saw, with a series of jagged sloping points or cusps on a long base. The Upper teeth have one primary sharp tapered cusp and two secondary cusps, perfect for holding large or small prey. The whole array is ideal for slicing apart both large quarry or holding smaller animals like crabs and squid. Obviously this shark has six gill slits which extend around onto the throat region. The eyes are large, sometimes reflecting the flourescent green retina.
The pectoral fins are large and triangular, the single dorsal fin is set well back towards the tail and situated above the anal fin and behind the pelvic fins. The tail has a large upper lobe with a sub-terminal notch below the tip.
The colour of this species is non descript, blackish to pale grey tending to chocolate brown, sometimes with one or two small scattered dark specks, and a pale streak along the lateral line. The ventral surface or belly is much lighter but not white. The trailing edges of the fins may be light or white, more so in juveniles.
Juveniles are born at 70 cm long and
grow to a huge 5 meters, becoming very bulky around the mid section.
The Bluntnose Sixgill Shark has a wide tropical to temperate international
distribution in all oceans. It is fairly common throughout it's range down to 2000 meters. In the northern summer they can be found in fairly shallow water, as little as 10 meters or less, in some areas of western Canada and no doubt in other areas as well.
Despite it being a well-known commercial species, very little is known
of the Bluntnose Sixgill Shark's biology except that females do not reach
breeding maturity until they are 4.5 m long. They then can carry enormous
litters up to and exceeding 100 young. They have a broad diet, feeding on both live prey including seals, fish, other sharks, crabs, octopus and squid as well as carrion.