Hoping to fend off the utter collapse of several groundfish populations, U.S. regulators voted on Friday to ban bottom-fishing next year on most of the continental shelf in the Pacific. The vote, by the Pacific Fishery Management Council, was geared especially toward protecting populations of nine types of rockfish — often sold in markets as red snapper — that have been overfished in recent years. The U.S. Department of Commerce must back the council’s proposal for it to go into effect Jan. 1. Environmentalists said the rules were a long time coming and may not be tough enough, while many in the fishing industry said they now feared for their jobs. Steven Kupillas of the Pacific States Marine Fisheries Commission said, “The potential impacts for every fishing industry up and down the coast are pretty severe. It’s like we are cutting off our arm to save our life.”