Tiger shark
A quarter of sharks and rays are threatened with extinction.

Sharks, rays and chimaeras are at a risk of extinction within a few decades, a new study reveals.

The study by the International Union for Conservation of Nature (IUCN) suggests that these species are at comparatively higher risk than most other groups of animals.

"Our analysis shows that sharks and their relatives are facing an alarmingly elevated risk of extinction. In greatest peril are the largest species of rays and sharks, especially those living in shallow water that is accessible to fisheries," Dr Nick Dulvy of IUCN said in a statement.

The researchers analysed the conservation status of 1,041 shark, ray and chimaera species and found that overfishing is the greatest threat to these species.

These species are caught for their meat and making dome products such as a Chinese tonic made from manta and devil ray gills and pharmaceuticals made from deep sea shark livers.

Researchers noted that demand for shark fin soup is a major factor in the depletion of not only sharks but also some rays with valuable fins, such as guitarfish.

Moreover, intentional killing of sharks due to the perceived risk that they pose to people or fishing gear has threatened at least 12 species with extinction.

The study published in the journal eLIFE further indicates that ray species are at a higher risk than sharks while a quarter of both sharks and rays are threatened.

"Surprisingly, we have found that the rays, including sawfish, guitarfish, stingrays, and wedgefish, are generally worse off than the sharks, with five out of the seven most threatened families made up of rays," Dr Colin Simpfendorfer, Professor of Environmental Science at James Cook University in Queensland, Australia, said.

"While public, media and government attention to the plight of sharks is growing, the widespread depletion of rays is largely unnoticed. Conservation action for rays is lagging far behind, which only heightens our concern for this species group."

According to the researchers, sharks, rays and chimaeras produce few young and grow slowly, which increases their risk of extinction due to overfishing.

The study seeks speeding up of actions for effective conservation of these exceptional species.