Most reef sharks, rays face demise, says study

PARIS — Nearly two-thirds of the sharks and rays that live among the world's corals are threatened with extinction, according to new research published on Tuesday, with a warning this could further imperil precious reefs.

Coral reefs, which harbor at least a quarter of all marine animals and plants, are gravely menaced by an array of human threats, including overfishing, pollution and climate change.

Shark and ray species — from apex predators to filter feeders — play an important role in these delicate ecosystems that "cannot be filled by other species", said Samantha Sherman, a research fellow at Simon Fraser University in Canada and wildlife group TRAFFIC International.

But they are under grave threat globally, according to the study published in the journal Nature Communications, which assessed extinction vulnerability data from the International Union for Conservation of Nature to look at 134 species of sharks and rays linked to reefs.

The authors found 59 percent of coral reef shark and ray species are threatened with extinction, an extinction risk almost doubles that of sharks and rays in general.

Among these, five shark species are listed as critically endangered, as well as nine ray species — all so-called rhino rays that look more like sharks than stingrays.

"It was a bit surprising just how high the threat level is for these species," Sherman told Agence France-Presse. "Many species that we thought of as common are declining at alarming rates and becoming more difficult to find in some places."

Sherman said the biggest threat to these species by far is overfishing.

Sharks are under the most threat in the Western Atlantic and parts of the Indian Ocean.

Last year, countries at a Convention on International Trade in Endangered Species summit approved a plan to protect dozens of shark and ray species, adding 21 coral reef species in addition to the 18 species already covered by the regulations.

Sherman said this was "a step in the right direction", but added that a global effort was needed to improve implementation, as the regulations themselves do not stop these species from being killed as "bycatch".

The study was carried out by an international team of experts from universities to government and regional oceanic and fishery organizations, as well as nongovernmental organizations across the world.

                                                                                                       Xinhua