PORTLAND, Maine (AP) The U.S. Supreme Court ruled Friday against Maine lobster fishermen who sought to block new fishing restrictions that are designed to protect rare whales.

The new rules make an approximately 950-square-mile area of the Gulf of Maine essentially off limits to lobster fishing from October to January. That’s to protect North Atlantic right whales, which are one of the rarest whales and number less than 340.

Members of Maine’s lobster fishing industry asked the high court to block the new restrictions after an appeals court ruled that the closure was legal. Justice Stephen Breyer rejected the appeal on Friday without comment, a spokesperson for the Supreme Court said.

The Maine Lobstering Union and others have argued that the restrictions will hurt the fishing industry economically. The restrictions are intended to protect the whales from lethal entanglement in fishing gear. That’s one of the biggest threats to their existence.

The union initially won emergency relief to stop the closure, but the 1st U.S. Circuit Court of Appeals then put it back on last month.

Environmentalists, who have long advocated for stronger laws to protect the whales, heralded the high court’s decision.

The court “was right to reject this unfounded attempt to halt reasonable efforts to protect one of the planet’s most endangered animals,” said Kristen Monsell, oceans legal director and senior attorney for the Center for Biological Diversity.

“Right whales are on the brink of extinction, and they shouldn’t be at risk of being entangled and killed by lobster gear,” Monsell said.

The population of North Atlantic right whales was decimated during the commercial whaling era, when they were hunted for their oil. More recently, they’ve struggled with poor reproduction and high mortality, and the already small population has begun to shrink.

The federal government in August unveiled a host of new rules designed to try to save the species from vanishing.