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Climate change poses threat to fish stocks, study finds

Fresh-caught Gulf of Maine cod were sorted at the docks in Gloucester, Mass.Gretchen Ertl/The New York Times

Over the coming decades, dozens of marine species from the Carolinas to New England will be threatened by the warming, changing currents and the increased acidity expected to alter the region’s waters, according to a new study by scientists at the National Oceanic and Atmospheric Administration.

Atlantic salmon, winter flounder, bay scallops, ocean quahogs, and other species may face the kind of trouble from climate change that has been linked in previous research to the decline of Atlantic cod, which has lost an estimated 90 percent of its population over the past three decades, the study found.

The authors of the study, released Wednesday by the journal Plos One, found that half of the 82 species they evaluated along the northeastern coast are “highly” or “very highly” vulnerable to the effects of climate change, meaning their populations and ability to reproduce are likely to decline.


“The results show that climate change presents significant challenges to the region’s fishery management and to its ability to sustain fishing communities,” said Jonathan Hare, a NOAA oceanographer who was the lead author of study.

The study also found that 80 percent of the species studied are likely to move beyond their normal habitats.

They are likely to follow the path of black sea bass and summer flounder, both of which have been found further north than ever before in recent years.

Those changes could have an impact on what the fish eat and on how the government manages their stocks.

“This is reshuffling the ecosystem, and we don’t have a good understanding of what the consequences will be,” Hare said.

Andrew Pershing, chief scientific officer of the Gulf of Maine Research Institute in Portland, said the main value of the study would be to help researchers decide what species need more scrutiny now.


“Hare and [his] colleagues have developed a thoughtful approach to making general predictions for lots of species,” said Pershing, who published a paper in the journal Science last year that linked the decline of the cod population to the warming waters of the Gulf of Maine.

But he said more in-depth research is needed to better understand the impact of the warming waters on particular species. His research found that the mean surface temperature of the Gulf of Maine rose 4 degrees between 2004 and 2013.

“Their predictions sacrifice precision for a high-level look at which species are most vulnerable to a changing ocean,” he said.

Advocates for commercial fishermen said they hope that the study changes how regulators interpret their assessments of the health of fish populations.

“It’s good to see that just because the fish aren’t there, it doesn’t mean that they are overfished,” said Robert Vanasse, executive director of Saving Seafood, a Washington-based group that represents commercial fishermen. “This study shows that it could also mean that the fish have moved.”

Environmental advocates said the study also raises concerns about how the federal government oversees fishing stocks.

They said new regulations should be drafted to change the way fish are monitored between regions and by regional councils.

“It is clear, but unstated, that the current management structure of a New England Fishery Management Council and a Mid-Atlantic Fishery Management Council will make less and less sense and will quickly become unworkable,” said Peter Shelley, senior counsel for the Conservation Law Foundation.


“New England fishermen will be seeing more fish managed by a council on which they have no representation,” Shelley said.

Peter Baker, director of northeast oceans for The Pew Charitable Trusts, said the study reflected the need for a “big picture” approach to managing fish stocks that “sets rules with the ecosystem’s changes in mind.”

The study did have good news for some fish: About a quarter of the species studied are likely to benefit from climate change, including butterfish, squid, and croaker.

Hare said his main concerns about the region’s fish stem from the increasing acidification of local waters. Increased precipitation, runoff, and melting glaciers are likely to change the chemical composition of seawater.

“This will have a major negative impact on the ability for clams and scallops to build their shells,” he said.

Hare also worries that the climate change models that his team used may be too conservative.

They assume that the region will not warm more than 1.5 degrees Celsius over the next 35 years, even though some models suggest that the region will warm more quickly.

“We live in one of the fastest warming regions in the world,” he said.

David Abel can be reached at dabel@globe.com. Follow him on Twitter @davabel.