Overfishing has cut shark and ray populations in half over the past 50 years ,
From SCIENCE ADVISER (10/12/24)…
Overfishing has cut shark and ray populations in half over the past 50 years
Thanks to Hollywood blockbusters like Jaws, sharks have earned a reputation as fearsome, man-eating predators. In real life, however, we humans pose a far greater threat to these fish than they do to us. Sharks and their close relatives, rays, have long been hunted for their meat, fins, and skins. There is also a global demand for products like shark liver oil and ray gill plates, both of which are used in traditional medicine.
According to new research published in Science, overfishing has cut shark and ray populations in half over the past 50 years , with more than a third of all species now facing the threat of extinction. The animals first started becoming depleted in rivers, estuaries, and coastal waters near shore. Over time, these declines spread out across the oceans and down into the depths of the deep sea. Large, ecologically important species—such as sawfishes and rhino rays—were the first to dwindle, followed by declines in hammerhead sharks, large stingrays, and many other species. Eventually, fisheries started going after skates and deep-water sharks.
Other threats, including climate change and coastal habitat degradation, have exacerbated the damaging effects of overfishing—disrupting food webs and causing marine ecosystems overall to become weaker and less diverse. And although sharks and rays are among the most threatened vertebrates on the planet, the global demand for shark meat has nearly doubled in the last two decades, according to a new report issued by the IUCN Species Survival Commission (SSC) Shark Specialist Group (SSG).
Despite these sobering trends, the new research also illustrates a clear path toward conservation. “Nations can reduce the extinction risk by lowering fishing pressure to sustainable levels, strengthening fisheries governance, and eliminating harmful subsidies,” study co-author Colin Simpfendorfer explains in a press release. Science-based strategies, he notes, have “already created bright spots” in several countries.
“The message is clear,” IUCN SSC deputy chair and SSG chair Rima Jabado, who led the new report, says in a statement. “With the precarious state of many of these species, we can’t afford to wait.”
Sharks and rays have declined dramatically since 1970, with more than a third of all species now facing the threat of extinction (main graph and blue bubbles). Although catch has stagnated (inset, dark gray), global fishing efforts continue to intensify, putting even more pressure on these already vulnerable populations (red). DULVY ET AL./SCIENCE (2024)
