Global research points to clear solutions to major declines in sharks and rays

A new global study blames overfishing for the more than 50% decline in shark and ray populations since 1970, but also offers a clear path forward to prevent further declines in their numbers. Professor Colin Simpfendorfer of James Cook University was a co-author of the analysis, published in the journal Science.

He said overfishing has shown that populations of cartilaginous fishes such as sharks, rays and chimeras (close relatives to sharks) have declined by more than half over the past 50 years.

“In addition to deliberate targeting and bycatch, threats to sharks are further exacerbated by habitat degradation, climate change and pollution. As a result, more than a third of chondrich species are now at risk of extinction. Professor Simpfendorfer said.

Lead author Professor Nicholas K. Dalby of Canada’s Simon Fraser University said the study shows how the decline first occurred in rivers, estuaries and coastal coastal waters, then spread across the ocean and then into the deep ocean. He said that it shows that the price has declined.

“The largest and most functionally important species, such as sawfish and sea rays, declined one after another, followed by large stingrays, eagle rays, angel sharks, hammerhead sharks, and requiem sharks. Eventually, the fishery turned to deep-sea sharks and skates. for the liver oil and meat trade,” Professor Dalby said.

Professor Simpfendorfer said that despite the worrying trends, the analysis reveals a clear path to a solution. “Countries can reduce the risk of extinction by reducing fishing pressure to sustainable levels, strengthening fisheries governance and eliminating harmful subsidies.

“Advances are already creating a silver lining for chondrichs in Australia, Canada, New Zealand, the United States, parts of Europe and South Africa,” he said.

Professor Simpfendorfer said chronic undervaluation and undermanagement of fisheries was particularly prevalent in countries with weak governance.

“Science-based fishing limits and measures to minimize incidental harvest, including spatial protection, ensure sustainability and restore species to their ecological, social and economic potential. It is essential to