Broadnose sevengill shark

How it lives

Sevengills live to about 30 years, with up to 49 recorded. Pups are born live after about 12 months, in litters of 82 to 95 and 40 to 53 cm long. Females mature at 11 to 21 years and males at 4 to 5 years (Wikipedia). It mostly cruises slowly near the bottom but can burst forward when hunting. It is found from the surface to about 570 m (FishBase), often in bays and estuaries, and typically shallower than about 80 m. It has seven gill slits and a single dorsal fin (Oregon Sea Grant).

Where it goes

Monterey Bay Aquarium says it may undertake significant migrations along coastal waters. At La Jolla, California, divers began reporting sevengills around 2007, and a photo-ID project started in 2010. A NOAA biologist quoted by Phys.org suggested possible reasons: more sharks after the 1994 gillnet moratorium, more divers, better cameras and social media. The project had no published results at that time, so the reason is still an open question.

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

IUCN rates it Vulnerable (2020 according to FishBase and Wikipedia), noting that it likely suffers great ongoing pressure from fisheries. It lives in temperate and subtropical waters worldwide except the North Atlantic and Mediterranean, including the Pacific coast from British Columbia to Chile. San Francisco Bay populations were depleted in the 1930s and 1940s for liver oil. Sport fishers in Australia and the United States still target it, and it is used for leather and liver oil. Monterey Bay Aquarium says limited fishery data elsewhere make wider assessments difficult. I found no global population count.