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
Genus: Hexanchus
Species: griseus
Taxonomic name: Hexanchus griseus
There are three species of sixgill sharks in Australian waters. The Frilled
Shark (Chlamydoselachus anguineus) is found only in very deep water, although
it will come near the surface on rare occasions. The Bigeye Sixgill (Hexanchus
nakamurai) and Bluntnose Sixgill (Hexanchus griseus) sharks may occur
in shallow water, especially when they are juveniles, but they are normally
found at depths of 90–2000 m.
The Bluntnose Sixgill Shark has a wide tropical to temperate international
distribution, being found locally in southeastern Australia, confined
areas of Queensland and Western Australia. It has green-tinted eyes and
a mouth that appears to be a tight-lipped grin. Its one dorsal fin is
set well back on the body, near the elongated tail. The torso is round,
almost chubby, and the six gill slits continue well around the throat.
The teeth of the lower jaw resemble a hand saw, with a series of jagged
sloping points on a long base. The upper teeth have similar rear-pointing
spikes but on a shorter base and with only three points, perfect for holding
large or small prey. The whole array is ideal for slicing apart both large
quarry, such as dolphins and sharks, as well as holding smaller animals
like crabs and squid.
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 which begin life at 70 cm long and
grow to a huge 5 m.