A study published in Fisheries Journal has found that the global catch of tuna, at 6 million metric tons annually, has increased by more than tenfold in the past 60 years, bringing the current system to an unsustainable level that could lead to extinction, reports The Guardian.

The study also found that 67 percent of global tuna catches are made in the Pacific Ocean by Japanese and American fleets, followed by 12 percent in the Indian Ocean and 12 percent in the Atlantic Ocean.

Sharks are most affected as bycatch, with blue sharks accounting for 23 percent.