Dusky shark

How it lives

A large, slender shark of coastal and offshore waters, found from the surface to about 400 m. Adults are commonly at 200 to 400 m and young stay in shallower water. It is one of the slowest-growing and latest-maturing sharks, maturing at around 16 to 23 years. It is live-bearing, with a litter of 3 to 14 pups according to FishBase. Estimates of pregnancy range from about 16 to 24 months, and females breed only every two to three years. Nursery areas have been identified in shallow inshore waters off KwaZulu-Natal, South Africa, the east coast of the United States and south-western Australia. The oldest age reported is 40 years.

Where it goes

Dusky sharks are highly migratory and can cover thousands of kilometres in one migration. In the western Atlantic and eastern Pacific they move north in summer and south in winter. In South Africa and Australia they move north in the austral winter and spring and south in summer and autumn. They separate by size and sex, and females move into shallow inshore waters to give birth.

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 assessed the dusky shark as Endangered worldwide in 2018, and it is listed on CMS Appendix II since 2017. CMS reports declines from 62 percent up to 99 percent in the Atlantic and up to 75 percent in the Indo-Pacific. Off the eastern United States, numbers were estimated in 2006 at about 15 to 20 percent of their mid-1970s level, and the stock remained overfished in the 2011 assessment, despite landing bans. In Australia, numbers fell by more than 75 percent between the 1970s and 2004, and the stock is now managed and recovering. Some older pages still show the earlier Vulnerable listing.