Southern New England lobster fishermen might have to start throwing back more small lobsters in an attempt to stem population losses.

New restrictions are on tap for the region’s historic lobster fishery, which is grappling with an unprecedented decline in some areas. Scientists have said lobsters off southern Massachusetts, Rhode Island and Connecticut have declined as ocean waters warm.

The regulatory Atlantic States Marine Fisheries Commission is considering ways to help preserve the species, and a report from the commission says one way to preserve lobsters could be to increase the minimum harvesting size. The commission’s lobster board might take action on the issue Thursday.

“The biggest challenge I see is trying to establish an appropriate goal to manage the fishery in the face of what the scientists are telling us is the decline caused by ocean warming,” said Dan McKiernan, a member of the lobster board.

New England lobster fishing is one of America’s oldest industries, and it was worth more than a half-billion dollars last year. Lobsters have remained plentiful for consumers, and prices have been relatively stable because of abundant supply from northern New England and Canada.

But the catch south of Cape Cod has plummeted, to about 3.3 million pounds in 2013, 16 years after it peaked in 1997 at about 22 million. The fishery commission’s report states that management strategies can do only so much if environmental conditions persist.

The possibility of new restrictions has some lobster fishermen on edge. Bill Lister, a Cape Cod lobsterman, said he is concerned for the livelihood of lobstermen who make their living south of the Cape.

“The scientists have been telling them the stocks are in trouble,” Lister said.

The commission’s lobster board will meet to discuss the issue in Alexandria, Virginia, near its headquarters. The board could vote on potential new rules, which could be followed in October or February by a vote to put the proposal out for public comment.