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.”

LET’S TALK ABOUT OPTIMISM FOR A CHANGE

Democracy and journalism are in crisis mode—and have been for a while. So how about doing something different?

Mother Jones did. We just merged with the Center for Investigative Reporting, bringing the radio show Reveal, the documentary film team CIR Studios, and Mother Jones together as one bigger, bolder investigative journalism nonprofit.

And this is the first time we’re asking you to support the new organization we’re building. In “Less Dreading, More Doing,” we lay it all out for you: why we merged, how we’re stronger together, why we’re optimistic about the work ahead, and why we need to raise the First $500,000 in online donations by June 22.

It won’t be easy. There are many exciting new things to share with you, but spoiler: Wiggle room in our budget is not among them. We can’t afford missing these goals. We need this to be a big one. Falling flat would be utterly devastating right now.

A First $500,000 donation of $500, $50, or $5 would mean the world to us—a signal that you believe in the power of independent investigative reporting like we do. And whether you can pitch in or not, we have a free Strengthen Journalism sticker for you so you can help us spread the word and make the most of this huge moment.

payment methods

LET’S TALK ABOUT OPTIMISM FOR A CHANGE

Democracy and journalism are in crisis mode—and have been for a while. So how about doing something different?

Mother Jones did. We just merged with the Center for Investigative Reporting, bringing the radio show Reveal, the documentary film team CIR Studios, and Mother Jones together as one bigger, bolder investigative journalism nonprofit.

And this is the first time we’re asking you to support the new organization we’re building. In “Less Dreading, More Doing,” we lay it all out for you: why we merged, how we’re stronger together, why we’re optimistic about the work ahead, and why we need to raise the First $500,000 in online donations by June 22.

It won’t be easy. There are many exciting new things to share with you, but spoiler: Wiggle room in our budget is not among them. We can’t afford missing these goals. We need this to be a big one. Falling flat would be utterly devastating right now.

A First $500,000 donation of $500, $50, or $5 would mean the world to us—a signal that you believe in the power of independent investigative reporting like we do. And whether you can pitch in or not, we have a free Strengthen Journalism sticker for you so you can help us spread the word and make the most of this huge moment.

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