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.”

We've never been very good at being conservative.

And usually, that serves us well in doing the ambitious, hard-hitting journalism that you turn to Mother Jones for. But it also means we can't afford to come up short when it comes to scratching together the funds it takes to keep our team firing on all cylinders, and the truth is, we finished our budgeting cycle on June 30 about $100,000 short of our online goal.

This is no time to come up short. It's time to fight like hell, as our namesake would tell us to do, for a democracy where minority rule cannot impose an extreme agenda, where facts matter, and where accountability has a chance at the polls and in the press. If you value our reporting and you can right now, please help us dig out of the $100,000 hole we're starting our new budgeting cycle in with an always-needed and always-appreciated donation today.

payment methods

We've never been very good at being conservative.

And usually, that serves us well in doing the ambitious, hard-hitting journalism that you turn to Mother Jones for. But it also means we can't afford to come up short when it comes to scratching together the funds it takes to keep our team firing on all cylinders, and the truth is, we finished our budgeting cycle on June 30 about $100,000 short of our online goal.

This is no time to come up short. It's time to fight like hell, as our namesake would tell us to do, for a democracy where minority rule cannot impose an extreme agenda, where facts matter, and where accountability has a chance at the polls and in the press. If you value our reporting and you can right now, please help us dig out of the $100,000 hole we're starting our new budgeting cycle in with an always-needed and always-appreciated donation today.

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