Global decline of oceanic shark and ray populations ‘staggering’, SFU experts warn

Oceanic shark and ray populations have declined 71 per cent in the last 50 years, according to a new analysis published in the journal Nature.

With three-quarters of these iconic species now threatened with extinction due to overfishing, Simon Fraser University (SFU) biologist Nick Dulvy hopes the paper will serve as a global wake up call.

“Knowing that this is a global figure, the findings are stark,” says Dulvy, a paper co-author and Canada Research Chair in Marine Biodiversity and Conservation. “If we don’t do anything, it will be too late. It’s much worse than other animal populations we’ve been looking at. 

“It’s an incredible rate of decline steeper than most elephant and rhino declines, and those animals are iconic in driving conservation efforts on land.”

The analysis was conducted by the Global Shark Trends Project, a collaboration between researchers from SFU, James Cook University, the Georgia Aquarium and the International Union for Conservation of Nature (IUCN) Shark Specialist Group. 

The researchers reconstructed the global abundance of oceanic shark and rays dating back to 1970. There’s no doubting overfishing is responsible for the alarming global decline, according to Nathan Pacoureau, the paper’s lead author who is now an SFU alumnus. Fishing pressure on oceanic sharks and rays has increased 18-fold since 1970.

“We can see the alarming consequences of overfishing in the ocean through the dramatic declines of some of its most iconic inhabitants,” says Pacoureau. “It’s something policy makers can no longer ignore. Countries should work toward new international shark and ray protections, but can start immediately by fulfilling the obligations already agreed internationally.”