Illegal shark killings have disturbed eco groups for years, but a new statistical report says sharks are far more endangered than anyone knew. The report estimates that about 100 million sharks—or 6.4% to 7.9% of all species—are killed every year around the world, National Geographic reports. But any shark-hunting that kills more than 4.9% of sharks will leave species like the porbeagle, white tip, and a few kinds of hammerheads unable to recover, researchers say.
"There’s a staggering number of sharks being caught every year and the number is way too high considering the biology of species," says the lead researcher at Dalhousie University in Halifax, Canada. The Dalhousie team combined reported shark killings with statistics from almost 100 former papers, but calls its tally conservative; the real number could reach 273 million. The problem: Many fishermen cut off the fin (for pricey shark-fin soup) and dump the shark back in the water, so the full shark is never declared and shark-fishing quotas aren't surpassed. (Read more sharks stories.)