PORTLAND, Maine (AP) — Gerry Cushman has seen Maine’s iconic lobster industry survive numerous threats in his three decades on the water, but the latest challenge — which might sound tiny — could be the biggest one yet.

Lobster fishing is a game of inches, and the number of inches is about to change. Fishing regulators are instituting a new rule that lobster fishermen must abide by stricter minimum sizes for crustaceans they harvest.

The impending change might be only 1/16th of an inch or 1.6 millimeters, but it will make a huge difference for fishermen when the fishery is already facing major threats from climate change and new rules designed to protect whales, numerous lobster fishers told The Associated Press.

Interstate fishery regulators, however, say the change is necessary to preserve the future of the lobster population off New England as the species shifts farther north with warming waters.

In addition to causing a dispute between fishermen and regulators, the change has led to confusion about the ramifications for international trade in one of the world’s most popular seafoods.

“We don’t need any more, really, on our plate. It’s just a lot going on, one fight after another,” Cushman, 55, a boat captain who fishes out of Port Clyde, said. “We don’t need anything in the marketplace to lower the price of lobsters.”

Fishermen are pushing back at the new rules slated to go into effect next summer, because they fear even such a small change could dramatically alter their ability to fish. They also say it would put them at a competitive disadvantage with Canada, which harvests the same lobster species and has more relaxed rules. Some worry the size change could glut the market with lobsters in future years.

But recent surveys have shown a decline in baby lobsters off Maine, and regulators with the Atlantic States Marine Fisheries Commission say that could foreshadow a decline in catch.

“We’re seeing a decline in recruits that will probably result in a decline in adults later on,” said Caitlin Starks, a senior fishery management plan coordinator with the commission.

America’s lobster catch is already dipping — the haul in Maine, which harvests most U.S. lobster, fell from a high of 132.6 million pounds in 2016 to 93.7 million last year.

The minimum size change applies to the Gulf of Maine, a piece of ocean off New England that’s one of the most important lobster fishing grounds in the world. Under commission rules, the legal harvesting size for lobsters would change there if the young lobster stock in the gulf dropped by 35%.

Officials said last year the stock declined by 39% when comparing 2020-22 to 2016-18. That surprised both regulators and fishermen, and led many fishermen to question the accuracy of the commission’s data.

Nonetheless, regulators say the minimum size on the gauges fishermen use to measure lobsters will increase to 3 5/16 inches (8.4 centimeters) on July 1 and grow another 1/16th of an inch two years later.

Some conservationists support of the changes, which they feel will protect lobsters from depletion from overfishing. That’s especially important “in the face of unprecedented climate change in the Gulf of Maine,” said Erica Fuller, an attorney in the ocean program at Conservation Law Foundation.

Scientists say the gulf is warming faster than most of the world’s oceans.

“Analysis shows that the proposed increase in gauge size will contribute to the long-term health and resiliency of the lobster stock by increasing its spawning stock biomass,” Fuller said.

The changes do not apply in Canada, which has an even larger lobster fishing industry than the U.S. Some fishing grounds there already allow smaller lobsters to be caught than U.S. rules allow.

Canadian authorities and trade groups are closely watching regulatory actions in the U.S.

This month, the Atlantic States commission approved new rules to prevent the U.S. from importing sub-legal lobsters from Canada. The Canadian government is “committed to working with the Canadian fishing industry to help ensure continued market access,” said Barre Campbell, a spokesperson for Fisheries and Oceans Canada.

Inability to sell lobsters to the U.S. could result in Canadians relying more on other foreign markets, said Geoff Irvine, executive director of the Lobster Council of Canada. China is a major buyer from both countries.

“If we can’t sell those percentages of that size lobsters to the U.S. anymore, we have to find places to sell it,” Irvine said. “What does that mean for prices, what does that mean for harvesters?”

The changes will likely have a major impact on the lobster industry but might not trickle down to U.S. consumers, said John Sackton, a longtime seafood industry analyst. Prices this summer have been down compared to recent years, according to trade data. Whether that continues depends in part on how large the catch is for the rest of the year, Sackton said.

Some scientists who study the fishery have supported the minimum size change. Richard Wahle, a retired University of Maine marine sciences professor who has studied lobsters for decades, called it a “prudent” measure to protect the fishery’s future.

But the lobster industry sees a different story, said Patrice McCarron, executive director of the Maine Lobstermen’s Association, the oldest and largest fishing industry association on the East Coast.

The association believes the action isn’t needed at this time.

While recent lobster hauls are down from the 2010s, the group argued in commission testimony that they remain much higher than previous decades and that lobsterman also face “extreme regulatory uncertainty due to future whale rules.”

Rep. Jared Golden, a Democratic congressman who represents the Maine coast, proposed an amendment in July to block the size changes.

“It’s clear that regulators need to work much closer with fishermen to keep the industry sustainable and competitive,” Golden said.

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