PORTLAND, Maine (AP) — Regulators voted Thursday to extend a shutdown preventing New England fishermen from catching shrimp, a historic industry that has recently fallen victim to warming oceans.

New England fishermen, especially those from Maine, used to catch millions of pounds of small pink shrimp in the winter, but the business has been under a fishing moratorium since 2014. Rising temperatures have created an inhospitable environment for the shrimp, and their population is too low to fish sustainably, scientists have said.

An arm of the regulatory Atlantic States Marine Fisheries Commission voted Thursday to shut down the fishery for at least another three years. Abundance of the shrimp remained “poor” this year despite slightly improved environmental conditions, the Atlantic States said in documents.

The decision came after shrimp harvesters were allowed to catch a small number of shrimp as part of an industry-funded sampling and data collection program. The fishermen, who battled some rough weather, caught only 70 shrimp totaling less than 3 pounds.

However, “even with the bad weather, exceptionally low catch levels observed throughout the program reinforce concerns about the viability of the northern shrimp stock in the Gulf of Maine,” the documents state.

New England shrimp were a winter delicacy when the fishery was active, and fishermen sometimes caught more than 10 million pounds (4,536 kilograms) of them in a year. The small pink shrimp were a small part of the country’s large wild caught shrimp industry, which catches some of the most valuable seafood in the world.

Maine’s catch of shrimp cratered in 2013, when fishermen caught less than 600,000 pounds (272,155 kilograms) of the crustaceans after hauling more than eight times that the previous year. Fishing groups have sometimes lobbied for the shrimping industry to be reopened on a smaller scale basis, but most former Maine shrimpers have moved on to other species.