Bluntnose Sixgill Shark

Overview

The Bluntnose Sixgill Shark is a large, primitive-looking predator found in tropical and temperate waters across the globe. Often associated with deep-sea environments, this species is easily recognized by its six pairs of gill slits and a single dorsal fin positioned far back on its body.

Distribution & habitat

This shark is a circumglobal species, inhabiting the outer continental and insular shelves as well as upper slopes. While it is typically found at depths between 180 and 1,100 meters, it has been recorded from the surface down to 2,500 meters. It often exhibits diel vertical migration, moving into shallower waters during the evening and returning to greater depths during the day.

Appearance

It possesses a heavy, fusiform body that tapers toward both ends, with a broadly rounded snout. Its coloration ranges from gray to brown or olive-green, fading to a paler shade on the underside, often featuring a light-colored stripe along the flanks. A defining feature is its unique dentition: the upper jaw contains smaller, pointed teeth, while the lower jaw features large, comb-shaped, saw-like teeth. Live specimens are frequently noted for their striking, fluorescent blue-green eyes.

Biology & behavior

As a generalist predator, the Bluntnose Sixgill consumes a diverse diet including various fish, rays, chimaeras, squid, crustaceans, and even seals. It is a slow-moving, deep-sea inhabitant that is known to be long-lived and slow-growing, making it particularly vulnerable to overfishing. Reproduction is viviparous, with females producing exceptionally large litters ranging from 47 to over 100 pups.