POINT JUDITH, R.I. - There was a time when whiting were plentiful in the waters of Rhode Island Sound, and Christopher Brown pulled the fish into his long stern trawler by the bucketful. "We used to come right here and catch two, three, four thousand pounds a day, sometimes 10," he said, sitting at the wheel of the Proud Mary as it cruised out to sea.

POINT JUDITH, R.I. � There was a time when whiting were plentiful in the waters of Rhode Island Sound, and Christopher Brown pulled the fish into his long stern trawler by the bucketful.

"We used to come right here and catch two, three, four thousand pounds a day, sometimes 10," he said, sitting at the wheel of the Proud Mary as it cruised out to sea.

But like many other fish on the Atlantic Coast, whiting have moved north, seeking cooler waters as ocean temperatures have risen, and they are filling the nets of fishermen farther up the coast.

Studies have found that two-thirds of marine species in the northeast United States have shifted or extended their range as a result of ocean warming, migrating northward or outward into deeper and cooler water.

Lobster, once a staple in southern New England, have decamped to Maine. Black sea bass, scup, yellowtail flounder, mackerel, herring and monkfish have all moved to accommodate changing temperatures.

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, now is 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 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.

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 such as 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, Sens. Richard Blumenthal and Christopher S. Murphy, both Connecticut Democrats, 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 Rep. Joe Courtney, also a Democrat from 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, executive director of the New England Fishery Management Council, they are difficult to execute.

"If you�re giving fish to somebody, you�re taking them away from somebody else," Nies said.

But even in the best case, trying to estimate the size of fish populations is an uncertain proposition. And the migration of species in response to warming temperatures has made the task considerably harder.

"From a scientific perspective, there are some really interesting questions," Pinsky said. "Where did the fish go? Did we eat them? Or did they go somewhere else? Those are questions we haven�t really had to grapple with."

A 2014 survey of butterfish � a small, silvery fish that provides food for many larger fish species and is popular in Japan � illustrated the problem with traditional assessment methods.

A previous survey of butterfish had been unsuccessful at figuring out how robust the population was � there was too much uncertainty in the assessment�s sampling of the fish. Because regulators could not make a judgment about the status of the species, butterfish fishing was temporarily suspended.

But when a team of scientists began talking to fishermen, they realized that the earlier survey had not taken into account the movements of the butterfish in response to changes in water temperature.

"What we learned from working with the fishermen was that the animals were probably occurring outside the survey," said John A. Manderson, a research biologist at the National Oceanic and Atmospheric Administration�s northeast fisheries science center.

Manderson and his colleagues developed a way to factor movement patterns and temperature shifts into models for assessing the fish. Once their work was incorporated into the next survey, which found that butterfish were still plentiful, the fishery reopened.

Manderson said that listening to fishermen, who are often in the best position to know how many fish there are and where they are, was the key to understanding what was occurring.

"What started out as an academic exercise turned into a collaborative one," Manderson said.

The changes are happening so fast that regulators will have to adapt quickly if they are to have any hope of keeping up. Marine species, Manderson said, are moving north at 10 times the rate of animals on land.

"Our ideas of property rights and laws are purely land-based," he said. "But the ocean is all about flux and turbulence and movement."

He added, "Even the science is too slow."