Bluntnose sixgill shark

How it lives

Sixgills give live birth. Litters are large, reported as 47 to 108 pups (FishBase) or 22 to 108 (Wikipedia), and pups are 60 to 75 cm long at birth. Males mature at about 3.15 m and 11 to 14 years, and females at about 4.4 to 4.5 m and 18 to 35 years. Gestation is thought to be more than two years. Females have been recorded entering Puget Sound to give birth.

Where it goes

The sixgill is mostly a deep-water shark. By day it stays deep, and at night it rises toward shallower water to feed. Off Oahu, four tagged sharks swam up to a minimum depth of about 300 m between midnight and 3 AM and reached 600 to 700 m around noon (Wikipedia). It is usually found at 180 to 1,100 m but has been recorded as deep as 2,500 m. Young sharks in Puget Sound show strong site fidelity (Washington Department of Fish and Wildlife).

We only draw a journey on the map when scientists have tracked it or clearly documented it. For this animal we have not found one yet.

Populations

Near Threatened (IUCN, assessed November 2019 per FishBase). FishBase rates its resilience as low, with a population doubling time of 4.5 to 14 years at minimum. It is caught commercially and by sport fishing worldwide, and sold fresh, frozen or dried and salted. In Washington State, recreational fishing for it is closed. A 2025 preprint, not yet peer reviewed, found a 93 percent decline in predicted abundance in the Mediterranean from 2012 to 2021, mainly from bycatch, and noted that the regional assessment still lists it as Least Concern.