A new analysis published today in the journal Nature documents an alarming, ongoing, global decline of oceanic shark and ray populations over the past 50 years, primarily due to overfishing. A team of experts from around the world assessed 31 species and found a 71% decline in global abundance since 1970, a period that saw a doubling of fishing pressure and a tripling of shark and ray catches. Three-quarters (77%) of oceanic shark and ray species now qualify as threatened with extinction under the Red List criteria of the International Union for Conservation of Nature (IUCN).

To shine light on and conserve rare shark, ray, and chimaera species (chondrichthyans), SFU researchers have developed a fully-resolved family tree and ranked every species according to the unique evolutionary history they account for.

Results from the 2017 IUCN Regional Red List assessment of 153 species of chondrichthyan fishes (sharks, rays, and chimaeras) indicate the Arabian Sea and adjacent waters are home to some of the most threatened chondrichthyan populations in the world.

Conventional wisdom holds that sharks can't be harvested in a sustainable manner because they are long-lived animals. It takes time for them to reproduce and grow in numbers. But, researchers reporting in Current Biology on February 6 have evidence to suggest that sustainable shark fishing can be done with careful, science-based management. In fact, they say, an outright shark ban won't work. The only way to protect sharks and the food security of people who depend on them is by managing shark fisheries sustainably.