Pershing Paper Gets National Attention

Announcements | Dec 31, 2015

A 2015 study from Dr. Andrew Pershing and colleagues highlights the impacts of a rapidly warming Gulf of Maine on cod, a key commercial species in the region.

Four people sit at a desk with microphones and respond to questions from an audience.
Chief Scientific Officer Andy Pershing discusses how the rapid warming of the Gulf of Maine is impacting cod.

In October, GMRI Chief Scientific Officer Andy Pershing and his colleagues were published in perhaps the most prominent scientific journal in America – Science magazine. Their new study explains how rapid warming of Gulf of Maine waters — faster than 99.9 percent of the global ocean — reduced the capacity of cod to rebound from fishing, leading to collapse.

“Cod are a key species here in the Gulf of Maine,” said Pershing. “We hope this study starts a conversation about how to best protect this species in the future.”

For centuries, cod were the backbone of New England’s fisheries and a key species in the Gulf of Maine ecosystem. Today, cod stocks are on the verge of collapse, hovering at 3-4% of sustainable levels. Even cuts to the fishery have failed to slow this rapid decline, surprising both fishermen and fisheries managers.

The rapid warming is linked to changes in the position of the Gulf Stream and to climate oscillations in the Atlantic and the Pacific. These factors add to the steady pace of warming caused by global climate change. In the face of already depleted cod stocks, fisheries managers in 2010 had placed a series of restrictions on harvesting this key Gulf of Maine species, but even strict quota limits on fishermen failed to help cod rebound.

“Managers kept reducing quotas, but the cod population kept declining,” said Pershing. “It turns out that warming waters were making the Gulf of Maine less hospitable for cod, and the management response was too slow to keep up with the changes.”

The models used by managers over the last decade to set the quotas for cod did not account for the impact of rising temperatures, leading to quotas that were too high. Fishermen stayed within their quotas, but still took more fish than the population could sustain.

“This creates a frustrating situation that contributes to mistrust between fishermen, scientists, and managers,” Pershing explains. “The first step toward adapting fisheries to a changing climate is recognizing that warming impacts fish populations.”

According to the report, recovery of Gulf of Maine cod depends on sound fishery management and on future temperatures. Cod are a coldwater species, and the Gulf of Maine is at the edge of their geographic range. As the ocean warms, the capacity of the Gulf of Maine to support cod will decline, leading to a smaller population and a smaller fishery.

To have a study published in Science is an extraordinary achievement. As such, the report received major media attention from hundreds of news outlets around the world.

Here are some media highlights: