Federal fishery regulators imposed a permanent ban Wednesday on bottom trawl fishing in nearly 150,000 square miles of federal waters off the West Coast.
In making the decision, the National Oceanic and Atmospheric Administration rejected a proposal crafted by environmentalists and the fishing industry that would have covered twice as much area.
The agency also decided against listing 13 oil derricks within the waters as "habitat areas of particular concern," a designation that might have slowed efforts by some environmentalists and coastal residents to have the structures removed.
Wednesday's action was spurred by a lawsuit by environmental groups that accused the federal government of mismanaging fish habitat.
Janis Searles, a senior counsel for Oceana, one of the groups, said she was glad the derricks weren't granted special protection but disappointed the trawling ban didn't cover a wider area.
"It's a bittersweet decision," she said.
Defenders of the platforms said millions of fish have adopted the derricks as habitat and could die if the structures were removed.
"We've got extremely valuable habitat there, and the habitat seems to be disregarded," said Tom Raftican, president of United Anglers, a conservation group that protects fishing interests.
The new regulations cover federal waters that extend from three miles to 200 miles off the coasts of California, Oregon and Washington.
Trawl fishing is already limited in California state waters and banned in Washington waters. Other types of fishing are allowed in the no-trawl zones.
Environmentalists said trawling has contributed to an economic disaster resulting from overfishing and poor ocean conditions.
The federal government has declared nine species overfished. Some fisheries have closed, and the groundfish fleet was cut by a third to allow remaining boats to earn a better living.
The trawling decision was designed to protect coral beds, kelp forests, rocky reefs and other sensitive fish habitat from damage by weighted nets used to scoop up bottom-dwelling species.
The 150,000 square miles where trawling was banned were listed as "essential fish habitat," a designation that requires federal agencies to try to protect them.
The ruling rejected a June proposal by the Pacific Fishery Management Council, which regulates West Coast fishing. That proposal, a compromise between environmentalists and fishermen, called for banning trawl fishing in 300,000 square miles of federal waters.
The oceanic and atmospheric administration opted not to ban fishing in depths of more than 3,500 meters (about 11,480 feet). Officials said there was no commercial fishing in the deep waters, and the habitat was not overfished.