A third of shark species threatened with extinction

Posted: 25 June 2009

The first study to determine the global conservation status of 64 species of open ocean (pelagic) sharks and rays reveals that 32 per cent are threatened with extinction, primarily due to overfishing.

According to the Shark Specialist Group of the World Conservation Union (IUCN), the percentage of open ocean shark species threatened with extinction is higher for the sharks taken in high-seas fisheries (52 per cent), than for the group as a whole.

Basking Shark illegally landed in Greece
Basking Shark illegally landed in Greece
Basking Shark illegally landed in Greece, March 2009. Photo © The Shark Alliance
"Despite mounting threats, sharks remain virtually unprotected on the high seas," says Sonja Fordham, Deputy Chair of the IUCN Shark Specialist Group and Policy Director for the Shark Alliance. "The vulnerability and lengthy migrations of most open ocean sharks call for coordinated, international conservation plans. Our report documents serious overfishing of these species, in national and international waters, and demonstrates a clear need for immediate action on a global scale."

The IUCN report comes days before Spain hosts an international summit of fishery managers responsible for high seas tuna fisheries in which sharks are taken without limit. It also coincides with an international group of scientists meeting in Denmark to formulate management advice for Atlantic porbeagle sharks.

More than 'bycatch'

IUCN experts classify Great Hammerhead (Sphyrna mokarran) and Scalloped Hammerhead (Sphyrna lewini) sharks, as well as Giant Devil Rays (Mobula mobular), as globally Endangered. Smooth Hammerheads (Sphyrna zygaena), Great White (Carcharodon carcharias), Basking (Cetorhinus maximus) and Oceanic Whitetip (Carcharhinus longimanus) sharks are classed as globally Vulnerable to extinction, along with two species of Makos (Isurus spp.) and three species of Threshers (Alopias spp.).

Porbeagle Sharks (Lamna nasus) are classified as globally Vulnerable, but Critically Endangered and Endangered in the Northeast and Northwest Atlantic, respectively. The Blue Shark (Prionace glauca), the world's most abundant and heavily fished open ocean shark, is classified as Near Threatened.

Spiny Dogfish caught in trawl net
Spiny Dogfish caught in trawl net
Spiny Dogfish caught in trawl net. Photo © The Shark Alliance
Many open ocean sharks are taken mainly in high seas tuna and swordfish fisheries. Once considered only incidental "bycatch", these species are increasingly targeted due to new markets for shark meat and high demand for their valuable fins, used in the Asian delicacy shark fin soup. To source this demand, the fins are often cut off sharks and the rest of the body is thrown back in the water, a process known as "finning". Finning bans have been adopted for most international waters, but lenient enforcement standards hamper their effectiveness.

Sharks are particularly sensitive to overfishing due to their tendency to take many years to mature and have relatively few young. In most cases, pelagic shark catches are unregulated or unsustainable. Twenty-four per cent of the species examined are categorized as Near Threatened, while information is insufficient to assess another 25 per cent.

"The completion of this global assessment of pelagic sharks and rays will provide an important baseline for monitoring the status of these keystone species in our oceans," says Roger McManus, Vice-President for Marine Programs at Conservation International.

The IUCN Shark Specialist Group wants governments to set catch limits for sharks and rays. It urges governments to fully protect Critically Endangered and Endangered species of sharks and rays, and ensure an end to shark finning.

It also wants governments to invest in shark and ray research, to minimize incidental bycatch of thede species and to use existing wildlife treaties to help conserve shared sharkand ray populations.

Source: IUCN, June 25. 2009