25pc of sharks and rays at high risk of extinction

A new assessment by the International Union for Conservation of Nature (IUCN) has revealed that a quarter of the world's sharks and rays are at risk of extinction.

The latest update to the IUCN's "Red List" of threatened species, which found ray species to be at higher risk than sharks, is part of a first-ever global analysis of these marine species.

Researchers assessed the conservation status of 1,041 shark, ray and chimaera species, which are all so-called "cartilaginous fish," meaning they have skeletons made of cartilage rather than bone. A chimaera is type of jawed fish closely related to sharks and rays.

The researchers found that sharks, rays and chimaeras face a substantially higher risk of extinction than do most other animals.

In fact, only 23 percent of shark, ray and chimaera species are categorized as being safe, or of "least concern," IUCN officials said.

Nick Dulvy, co-chair of the IUCN Shark Specialist Group and Canada Research Chair at Simon Fraser University in British Columbia, Canada, said in a statement that the analysis shows that sharks and their relatives are facing an alarmingly elevated risk of extinction, LiveScience reported.

He said that in greatest peril are the largest species of rays and sharks, especially those living in shallow water that is accessible to fisheries, where they can become entangled in fishing gear a phenomenon known as bycatch.