PORTLAND, Maine — An organization that represents Maine's lobster fishermen is pulling its support of a proposed plan to protect endangered whales.

The subject of North Atlantic right whale conservation has been a major source of contention for the lobster fishery in Maine, which supplies by far the most U.S. lobster. There are only about 400 of the whales, which are prone to entanglement in fishing gear.

The Maine Lobstermen's Association has taken a closer reading of the science behind the plan, which a federal team recommended in April, and believes it places too much of the onus on lobster fishermen, association executive director Patrice McCarron said.

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The plan, when adopted into law, could result in the removal of 50% of Maine's lobster trap lines from the water. The industry deserves a plan that takes into account the risk whales face from ship strikes and other types of fishing gear, McCarron said.

"We are in no way saying that we feel the Maine lobster fishery is going to walk away from its responsibility. We remain committed to finding management measures that reflect the risk our fishery poses to right whales," she said.

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The next step for the whale plan is for the National Oceanic and Atmospheric and Administration's National Marine Fisheries Service to develop it into proposed rules, said Jennifer Goebel, a spokeswoman. That could happen by year's end.

The agency plans to address the Maine Lobstermen's Association's decision to withdraw support but wasn't ready to do so yet on Wednesday, Goebel said. The goal is for implementation of rules by July 2020, she said.

Environmental groups have long called for stricter fishing rules to protect right whales. The lobstering group's decision to pull back from the agreement is "disappointing," but shouldn't be allowed to jeopardize the drive for better protections, said C.T. Harry, marine campaigner at the International Fund for Animal Welfare.

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The end goals are "practical solutions that both address the crisis facing the critically endangered North Atlantic right whale and ensure the long-term success of the lobstering industry," Harry said.

Maine's lobstering industry is critical to the state's economic health. The state's lobsters were worth nearly half a billion dollars at the docks last year.