According to a statement from the International Union for Conservation of Nature (IUCN), a quarter of the Earth’s shark and ray species are now threatened with extinction.

The IUCN Shark Specialist Group (SSG) recently completed the first ever global analysis. The report includes the conservation status of 1,041 shark, ray and related chimera species. It categorizes only 23 percent of these groups as “Least Concern,” the lowest percentage of species considered safe of any animal group.

“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,” says Dr Nick Dulvy, IUCN SSG Co-Chair and Canada Research Chair at Simon Fraser University in British Columbia.

The primary threat to these species, directly and indirectly, is overfishing. While the problem of accidental catches of sharks and rays has become well known in recent years, overfishing and scarcity of other fish has made the “bycatch” more and more lucrative. Currently ray species are considered the most endangered. There has been growing public concern about shark fishing and the shark fin market, but the fishing of rays has gone largely unnoticed.

“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,” says Dr Colin Simpfendorfer, IUCN SSG Co-Chair and Professor of Environmental Science at James Cook University in Queensland, Australia. “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.”

Cartilaginous fish, so called because their skeletons are made of cartilage rather than bone, are one of the world’s oldest known and most diverse groups of animals. Sharks, rays and chimaeras are all part of this group.

The study, a result of collaboration between 302 experts from 64 countries, was published in the journal eLIFE. It comes at the start of the year, marking the 50th anniversary of the IUCN Red List.

Source: IUCN