Yet fishing regulations, which among other things set legal catch limits for fishermen and are often based on where fish have been most abundant in the past, have failed to keep up with these geographical changes.
The center of the black sea bass population, for example, is now in New Jersey, hundreds of miles north of where it was in the 1990s, providing the basis for regulators to distribute shares of the catch to the Atlantic states.
Under those rules, North Carolina still has rights to the largest share. The result is a convoluted workaround many fishermen view as nonsensical. Because black sea bass are now harder to find in their state waters, North Carolina fishermen must steam north 10 hours, to where the fish are abundant, to even approach the state’s allocation. Mr. Brown and other New England fishermen, however, whose states have much smaller shares, can legally land only a small fraction of the black sea bass they catch and must throw the rest overboard. And New England states like Maine, where fishermen are beginning to catch black sea bass regularly, have only a tiny allocation and no established fishery.
“Our management system assumes that the ocean has white lines drawn on it, but fish don’t see those lines,” said Malin L. Pinsky, an assistant professor in the department of ecology, evolution and natural resources at Rutgers University, who studies how marine species adapt to climate change. “And our management system is not as nimble as the fish.”
The mismatch between the location of fish and the rules for catching them has pitted recreational fishermen against commercial ones and state against state. It has heightened tensions among fishermen, government regulators and the scientists who advise them and raised questions for fishery managers that have no easy answers.
Reflecting these tensions, Senators Richard Blumenthal and Christopher S. Murphy, both Democrats of Connecticut, noted in a letter to the acting inspector general of the Commerce Department in June that fishermen in their state were experiencing “extreme financial hardship” because the apportionment of resources was so outdated.
“We request that your office investigate how the current system impacts the region’s fishermen and whether the structure should be reformed to bring quota allocations in line with current data on actual fish population distribution,” the senators, joined by Representative Joe Courtney, also a Democrat of Connecticut, wrote. “As species of fish move north, the allocation levels should migrate with them.”
Although such shifts in allocations are possible, said Tom Nies, the executive director of the New England Fishery Management Council, in practice they are difficult to execute.
“If you’re giving fish to somebody, you’re taking them away from somebody else,” Mr. Nies said.
But, he added, fishery managers at state and federal levels are examining ways to take into account the effects of warming ocean temperatures. Those approaches include changes in how permits are structured and giving states with nascent fisheries representation in councils that oversee states where the fish are well-established.
“I would be surprised if you find very many fishermen who will tell you that climate change is not happening,” he said. “I think there’s a clear recognition from everybody that this is a problem, and a lot of people are working on how to address it.”
One approach being actively pursued by scientists and managers is developing methods to incorporate temperature data and other characteristics of the environment into the surveys that regulators use to set fishing quotas.