The settlement reinstates a limit of 17 on the number of loggerhead sea turtles the fishery is allowed to accidentally hook or entangle each year, both sides said Monday.

This means longline boats must stop fishing for swordfish when 17 turtles are caught. The cap had been in place for five years until 2009, when the National Marine Fisheries Service raised the limit to 46.

The turtles are a migratory species that crisscross the Pacific. They nest in Japan then swim to Mexico’s Baja California and the Sea of Cortez to feed.

The accidental snagging of the turtles by fishing gear, along with damage to their nesting areas, is such a threat to the reptile that the National Marine Fisheries Service and the U.S. Fish and Wildlife Service had separately recommended last year that turtles be placed on the endangered species list.

"It made absolutely no sense to have one arm of the Fisheries Service increasing the lethal capture of loggerheads, while the other arm is in the process of determining whether the listing for loggerheads should be changed from threatened to endangered," said Todd Steiner, biologist and executive director of Turtle Island Restoration Network, one of the groups that sued. "With extinction looming, these animals need more protection, not less."

Earthjustice represented the plaintiffs, which also included Kahea and the Center for Biological Diversity.

Michael Tosatto, the regional administrator for the National Marine Fisheries Service, said in a statement the agency has also agreed to study the effects of the revised regulations.

The fisheries service imposed the 17 turtle bycatch limit the first time in 2004, as the industry began to test the use of circle hooks and mackerel-type bait shown to reduce bycatch. The fishery had been shut down for two years before that because it was catching too many sea turtles.

Most turtles mistakenly caught or hooked since 2004 haven’t been mortally wounded.

The fisheries service maintains a separate limit for Pacific leatherback turtles, a migratory sea turtle that nests in Indonesia and Papua New Guinea and swims 6,000 miles to the U.S. West Coast to feed on jellyfish off California and Oregon. The longline industry is not allowed to hook or entangle any more than 16 of these turtles each year.

Longline fishing vessels string a line in the ocean, ranging from one mile to 50 miles long, to catch fish. They run smaller lines with baited hooks off the central line and wait for bait to attract fish.