Humans now kill 80 million sharks per year, 25 million of which are threatened species

A pile of 7 dead sharks lay together on a dirty tiled floor.
In 2018, on November 15, requiem and hammerhead sharks landed in Cox's Bazar, Bangladesh. (Image credit: Nidhi Gloria D’Costa)

An estimated 80 million sharks are dying in fisheries each year despite global regulations aimed at protecting them from finning, scientists have discovered. 

In a study published Jan. 11 in the journal Science, researchers used data from 2012 to 2019 — when legislation to protect sharks from finning increased tenfold — and found that annual shark mortality rose from 76 million in 2012 to over 80 million in 2017. Of those shark deaths, 25 million, or over 30%, represented threatened species. 

The researchers reviewed fisheries data from 150 countries and in the high seas, as well as using computer modeling and interviews with experts — including scientists, governments, environmental advocates and fisheries workers — to check their estimates. 

"We tried to be as proactive as possible in getting the highest-quality data," lead author Boris Worm, a marine ecologist at Dalhousie University in Canada, told Live Science. "I don't think anyone has ever looked at this question at this scale." 

Overfishing is a huge threat for sharks, which are often targeted for their fins or accidentally killed as bycatch. But the study revealed that legislation to prevent shark finning hasn't reduced the number of sharks killed and may have even caused it to increase.

"That's a big concern, because one in three species is threatened with extinction," Worm said.

Fins removed from a number of shark species at Cox’s Bazar in Bangladesh in 2018. (Image credit: Nidhi Gloria D’Costa)

Related: Super-healing shark regrows its fin after humans cut a huge chunk off

The overall increase was largely caused by mortality hotspots in coastal waters. The study saw shark deaths in coastal fisheries rise by 4%. "Now that finning regulation exists, fishers are keeping the whole shark," study co-author Laurenne Schiller, a fisheries conservation scientist at Carleton University in Canada, told Live Science. 

This could have caused new markets for shark meat to open up. "You might have even incentivized shark fishing in certain places because of this new demand for shark meat," she said. 

Adult bonnethead sharks for meat sale at the Bragança fish market, Brazil. (Image credit: Leonardo Manir Feitosa)

The increase in shark mortality correlates with an increase in the value of the shark trade. A WWF report based on the same period (2012 to 2019) estimated that the global trade in shark and ray meat could be worth $2.6 billion. Before this, the market was estimated to be worth $157 million in 2000, rising to $379.8 million in 2011.

Deaths in offshore fisheries decreased by 7%. Offshore fisheries "used to be thought of as the main culprits for finning," Schiller said, but these vessels are no longer allowed to retain certain species onboard. "That means that sharks may get caught, but if they're released, they have a chance of survival," she said.

The authors told Live science that more needs to be done to protect sharks by directly targeting mortality, not just finning. Measures including banning shark fishing, enforcing science-based catch limits, protecting critical areas, and demonstrating the value of live sharks could help to reduce deaths globally. 

"More than anything, this study is showing the global extent of the shark market — not just for fins but also for meat," Schiller said. People can reduce their own impact on sharks by being mindful of their actions — for example, by not buying shark teeth souvenirs, refusing to eat shark (which can be mislabeled, but is can also sometimes be listed under other names, such as huss or rock salmon) and avoiding cosmetics that use shark-derived squalene. 

"It's a solvable problem," Worm said. "But it's a problem that really needs to be tackled now, because sharks have not much time left."

Melissa Hobson
Live Science Contributor

Melissa Hobson is a freelance writer who specializes in marine science, conservation and sustainability, and particularly loves writing about the bizarre behaviors of marine creatures. Melissa has worked for several marine conservation organizations where she soaked up their knowledge and passion for protecting the ocean. A certified Rescue Diver, she gets her scuba fix wherever possible but is too much of a wimp to dive in the UK these days so tends to stick to tropical waters. Her writing has also appeared in National Geographic, the Guardian, the Sunday Times, New Scientist, VICE and more.