The tresher shark (Alopias vulpinus) is a member of the family of the tresher sharks (Alopiidae) and the order of the mackerel sharks (Lamniformes).
It is named for its long, elegant tail, that can be as long as the rest of its body and can be used to stun prey by hitting it.
The tresher shark lives on the continental shelf, close to the shore, but also in the open ocean. Subadults are occasionally observed in close proximity of beaches and in shallow bays.
This shark species feeds on schooling fish like mackerels, cephalopods, crustaceans, but sometimes also on sea birds. It is very occasionally observed in the North Sea.
The tresher is ovoviviparous, the embryos develop in the mother, feeding on the yolk sac and the ova produced by the mother after the yolk sac is absorbed. A litter has 2 to 4 young, that can be more than 1 meter long.
- Maximum length: 550 cm
- Maximum weight: ? kg
- Maximum lifespan: 25 to 50 years
- Habitat: 0 to 360 meter depth
- Catches: there are targeted fisheries for tresher sharks, but the tresher is often caught as bycatch. Because of its slow reproducation, all populations are threatened. It is assumed, that tuna and swordfish boats are catching more and more tresher sharks. In the Mediterranean, young animals are often caught as bycatch, but also targeted by recreational anglers and swordfish boats.
- Status: ‘Vulnerable’ in the northwestern and western Atlantic, ‘Vulnerable’ in the Mediterranean on the international IUCN Red List (http://www.iucnredlist.org/).