The shortfin mako, the world’s fastest known shark, which can reach speeds of up to 70 kilometers per hour (43 miles an hour), is one step closer to extinction.
According to the Shark Specialist Group (SSG) of the IUCN (International Union for Conservation of Nature), which assessed the population trends of 58 species of sharks and rays and updated their conservation status on March 21, 17 species are now threatened with extinction. For some species, their reviewed classifications bring them to the brink of extinction.
The shortfin mako (Isurus oxyrinchus), for example, has been uplisted from vulnerable to endangered, as has its cousin, the longfin mako (Isurus paucus). Both makos, prized for their meat and fins and sought after by recreational anglers, are overfished and don’t have any fishing quotas regulating their harvests.
“Our results are alarming and yet not surprising, as we find the sharks that are especially slow-growing, sought-after, and unprotected from overfishing tend to be the most threatened,” Nicholas Dulvy, SSG co-chair and professor of marine biodiversity and conservation at Simon Fraser University in Canada, said in a statement. “Of particular concern is the fast and iconic Shortfin Mako Shark, which we’ve assessed as Endangered based on serious depletion around the globe, including a 60% decline in the Atlantic over about 75 years.”
The greeneye spurdog (Squalus chloroculus), too, has been classified as endangered, moving up from its previous listing as near threatened. With a pregnancy that lasts nearly three years, the greeneye spurdog is extremely slow-growing, which makes it particularly vulnerable to fishing pressure, researchers say.
Three shark species — the Argentine angelshark (Squatina argentina), whitefin swellshark (Cephaloscyllium albipinnum) and smoothback angel shark (Squatina occulata) — have been uplisted to critically endangered from lower threat categories. At the same time, some species with relatively healthy populations continue to remain in the “least concern” category. These include species that are either not heavily sought after, such as the pelagic stingray (Pteroplatytrygon violacea), or those that live in depths that fishing gear can’t reach easily, like the megamouth shark (Megachasma pelagios).
“The threats to sharks and rays continue to mount and yet countries around the world are still falling far short of their conservation commitments, particularly with respect to basic limits on catch,” Sonja Fordham, SSG deputy chair based at Shark Advocates International, a project of Washington, D.C.-based The Ocean Foundation, said in the statement. “To turn the tide and allow shark and ray recovery, the SSG is calling for immediate national and international fishing limits, including complete bans on landing those species assessed as Endangered or Critically Endangered. The need for action is urgent.”
Header image: Shortfin mako shark. Image by Mark Conlin/SWFSC Large Pelagics Program via Wikimedia Commons (Public domain).