A third of the 64 species of high-seas sharks are threatened with extinction because they are overfished or killed incidentally in swordfish and tuna catches, a leading conservation group warned Thursday.
The International Union for Conservation of Nature, the producer of the world's Red List of Threatened Species, released its shark study ahead of a meeting in Spain next week of tuna fishery managers. The gathering includes those responsible for fisheries "in which sharks are taken without limit," IUCN said.
In those areas with fisheries, the IUCN added, the danger is even greater, with half of all species there threatened with extinction.
"Despite mounting threats, sharks remain virtually unprotected on the high seas," said Sonja Fordham, a shark specialist for the group. "The vulnerability and lengthy migrations of most open ocean sharks call for coordinated, international conservation plans."
The great and scalloped hammerhead sharks and the giant devil ray are globally endangered, IUCN said. The basking and oceanic whitetip sharks, two Mako species and three Thrashers join the iconic great white shark as globally vulnerable to extinction.
IUCN said ocean sharks were often only incidental bycatch as fishermen sought tuna and swordfish. But new markets for shark meat, especially the fins used in Asian soups, are driving demand.
The worst response from the fisheries industry has been "finning," which is when the fins are cut off and the rest of the shark's body is dumped back in the sea, IUCN said. The practice has been banned in most international waters, but the rules are poorly enforced, it said.
Sharks take many years to mature and have few offspring, making them particularly sensitive to overfishing, IUCN said.