Overfishing Large Sharks Impacts Entire Marine Ecosystem

Fight disinformation: Sign up for the free Mother Jones Daily newsletter and follow the news that matters.


Ransom’s Myers last paper before his death this week reports that fewer big sharks in the oceans also means bay scallops are harder to find at market. Ecologists and scientists have thought for a long time that the effects of removing the ocean’s top predators, big sharks, would cascade through the food web. This is the first study to demonstrate that cause and effect—a holy grail of conservation biology.

A team of Canadian and American ecologists, led by Myers and Julia Baum, found that overfishing the largest predatory sharks (such as bull, hammerhead, dusky, and great white sharks) along the Atlantic Coast led to an explosion of ray, skate, and small shark prey species, according to a Dalhousie University press release. Myers held the Killam Chair in Ocean Studies at Dalhousie. The paper appears in this week’s Science.

“With fewer sharks around, the species they prey upon – like cownose rays – have increased in numbers and in turn, hordes of cownose rays dining on bay scallops have wiped the scallops out,” says Julia Baum, a co-author of the article. “Large sharks have been functionally eliminated from the east coast of the U.S., meaning that they can no longer perform their ecosystem role as top predators. The extent of the declines shouldn’t be a surprise, considering how heavily large sharks have been fished in recent decades to meet the growing worldwide demand for shark fins and meat.

“Our study provides evidence that the loss of great sharks triggers changes that cascade throughout coastal food webs,” says Baum. “Solutions include enhancing protection of great sharks by substantially reducing fishing pressure on all of these species and enforcing bans on shark finning both in national waters and on the high seas.”

LESS DREADING, MORE DOING

This is the rubber-meets-road moment: the early days in our first fundraising drive since we took a big swing and merged with CIR to bring fearless investigative reporting to the internet, radio, video, and everywhere else that people need an antidote to lies and propaganda.

Donations have started slow, and we hope that explaining, level-headedly, why your support really is everything for our reporting will make a difference. Learn more in “Less Dreading, More Doing,” or in this 2:28 video about our merger (that literally just won an award), and please pitch in if you can right now.

payment methods

LESS DREADING, MORE DOING

This is the rubber-meets-road moment: the early days in our first fundraising drive since we took a big swing and merged with CIR to bring fearless investigative reporting to the internet, radio, video, and everywhere else that people need an antidote to lies and propaganda.

Donations have started slow, and we hope that explaining, level-headedly, why your support really is everything for our reporting will make a difference. Learn more in “Less Dreading, More Doing,” or in this 2:28 video about our merger (that literally just won an award), and please pitch in if you can right now.

payment methods

We Recommend

Latest

Sign up for our free newsletter

Subscribe to the Mother Jones Daily to have our top stories delivered directly to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate