Fisheries regulators and the seafood industry are grappling with the possibility that some once-profitable species that have declined with climate change may not return.
Several commercial species caught by U.S. fishermen are facing quota cuts, seasonal closures and other restrictions as populations have fallen and waters have warmed. In some cases, such as the fishing industry for species such as flounder in the Northeast, the changing environment has made it difficult for the fish to recover from years of overfishing that had already taxed the population.
Alaska officials have canceled the Bristol Bay fall king crab harvest and the winter king crab harvest, dealing a blow to the Bering Sea crab industry, which is sometimes worth more than $200 million a year, as the population has declined due to warming waters. The Atlantic cod fishery, once a vital New England industry, is now virtually closed. But even with depleted populations threatened by climate change, regulators rarely shut down the fishery entirely, as they are considering doing for New England shrimp.
Once a seafood delicacy, the northern shrimp has been under a fishing moratorium since 2014. Scientists believe that warming waters are wiping out their populations, and they will never come back. As such, the Atlantic States Marine Fisheries Regulatory Commission is now considering making the moratorium permanent, effectively ending the centuries-old shrimp harvest.
That’s a serious siren call for several species caught by U.S. fishermen that regulators say are at the limit. Other soft-shelled shellfish include winter flounder, Alaskan snow crabs and teal salmon.
It’s hard to say exactly how many fisheries are threatened primarily by warming waters, but more reductions and closures are likely in the future as climate change intensifies, said Malin Pinsky, director of Rutgers University’s Graduate School of Ecology and Evolution.
“We need to get used to this pattern of climate change and how it affects the population and the coastal economy,” Pinsky said. “A lot of years are pushing us beyond what we’ve experienced historically, and we’ll continue to see these new conditions as the years go by.”
While it is unclear whether climate change was ever the dominant factor in the eventual demise of the US fishery, global warming is the main reason that several once-reliable fisheries are in increasingly poor condition and under increased pressure regulation in recent years. Scientists say rising temperatures are leading to new predators, forcing species to shift their population centers north, or making it harder for them to grow to maturity.
In the case of the northern shrimp, scientists and regulators said at a meeting in August that the population has not recovered after nearly a decade of no commercial fishing. Regulators will review the possibility of a permanent moratorium this winter, said Dustin Colson Lining, fisheries management plan coordinator for the Atlantic Commission. Another approach could be for the commission to relinquish oversight of the fishery, he said.
Shrimp prefer cooler temperatures, but the Gulf of Maine is warming faster than most of the world’s oceans. Warming waters have also moved new predators into the bay, scientists say.
But in Maine, home to the cold-water shrimp fishery, fishermen have tried to argue that shrimp abundance is cyclical and that any moves to end the fishery for good are premature.
“I want to look into the future of this. This is not an unprecedented shrimp loss. We went through it in the 50s, we went through it in the 70s, we had a tough time in the 90s,” said Portland shrimper Vincent Bolzano. – They came back.
Another threatened species is the winter flounder, once highly sought after by southern New England anglers. The National Oceanic and Atmospheric Administration described the fish as “significantly below target population levels” at George’s Bank, a key fishing location. Scientists from the University of Rhode Island and the Rhode Island Department of Environmental Protection wrote in a report last year that the fish are struggling to reach maturity “due to increased predation associated with warming winters.”
On the West Coast, teal salmon are threatened with extinction due to climate change, according to NOAA. Scientists say the drought has worsened the fish’s prospects in California, at the southern end of its range.
Fishermen on the East Coast, from Virginia to Maine, have harvested the soft clams from the tidal mud for centuries, and they are a staple of seafood restaurants. They are used for soup and stir-fries of shellfish and are sometimes called “steamers”.
But the shellfish harvest has declined from about 3.5 million pounds (1.6 million kilograms) in 2010 to 2.1 million pounds (950,000 kilograms) in 2020 as the industry struggles with an aging workforce and increased competition from predators. such as crabs and worms. Scientists link the increase in the threat of predators to warming water.
In 2020, Maine’s largest shellfish harvest was the lowest in more than 90 years. And the 2021 catch still lagged behind typical catches in the 2000s, which were consistently close to 2 million pounds (907,000 kilograms) or more.
Projecting what the shellfish harvest will look like in 2022 is difficult, but the industry remains threatened by the growing presence of invasive green crabs, said Brian Beal, a professor of marine ecology at the University of Maine at Machias. The mollusk-eating crabs are native to Europe and arrived in the U.S. about 200 years ago, and their populations have grown as the water has warmed.
“It looks like there are a ton more green crabs than in 2020,” Bill said. – This is not a good sign.
One of the challenges of managing fisheries that are shrinking because of warming waters is that regulators rely on historical data to set quotas and other rules, said Lisa Kerr, a senior fellow at the Gulf of Maine Research Institute in Portland, Maine. Scientists and regulators are learning that some fish stocks simply cannot return to the productivity levels of 40 years ago, she said.
At the time, American fishermen typically caught more than 100 million pounds (45.4 million kilograms) of Atlantic cod per year. They now typically catch less than 2 million pounds (907,000 kilograms) as overfishing and environmental changes have prevented populations from returning to historic levels.
The future of managing species in such poor condition may require accepting the possibility that full recovery may not be possible, Kerr said.
“It’s really a reset of expectations,” she said. “We’re starting to see targets that are more aligned, but below the overall target.”