Huge, super-efficient drift nets of the kind that ignited a storm of international protest in the Pacific Ocean have been spotted for the first time in the Atlantic near the Caribbean, raising fears that Atlantic marine life could be threatened and that commercial and sport fisheries important to the eastern United States could be devastated.The big nets, made of lightweight filament that is largely invisible underwater, are typically released to drift at night on the high seas. They can stretch up to 40 miles, hanging vertically to a depth of about 30 feet, catching fish by their gill covers and trapping marine mammals who are then unable to get to air.Asian fishermen who use them in the Pacific have come under increasing international pressure from critics in many nations who charge that the nets seriously deplete stocks of sought-after commercial fish and indiscriminately trap and kill porpoises, seabirds and a wide variety of fish not sought by the fishermen. Now Taiwanese using drift nets appear to have moved into the Atlantic, possibly in response to the pressure elsewhere, and the critics fear the nets will threaten populations of large migratory fish like tuna, swordfish, sharks, marlin and sailfish that move through United States waters. A resolution adopted unanimously by the United Nations General Assembly last December called for a worldwide moratorium on high-seas use of drift nets after June 30, 1992, and said that further expansion of the practice should ''cease immediately.'' Damage Could Come in 2 YearsTaiwan is not a United Nations member. Its government reportedly has said it will comply with the U.N. resolution, but this could not be immediately confirmed.. In any event, conservationists say, large-scale use of the nets, could cause much damage in the Atlantic in the next two years. Jeff Yao, a spokesman for the Coordination Council for North American Affairs, which represents the Taiwanese Government in Washington, said he had no knowledge of any Taiwanese drift net operations in the Atlantic. He said Taiwan's goal was to phase out use of the nets, but that this would take time. Taiwanese fishermen ''understand the importance of the protection of ocean life and also the ocean resource,'' Mr. Yao said. He said he did not know what his country's stance on the U.N. resolution was. ''If those fellows eat up the Atlantic, we've had it,'' said Sid Johnson, the secretary of the Trinidad and Tobago Game Fishing Association, who said he has observed and photographed 15 Taiwanese vessels at the dock in Port of Spain, where he lives. His report is believed to be the first evidence of the nets in the Western Atlantic-Caribbean region, and it has raised loud alarms among marine conservationists. The State Department, expressing concern, has asked the Taiwanese government for answers. But Larry Snead, the director of fisheries affairs for the department, said none has so far been forthcoming. Taiwanese using drift nets have also been reported in Atlantic waters off some African nations in the last six months, Mr. Snead said, and still other reports have placed fishermen using the nets in the Indian Ocean. Fishing Boats From Taiwan But Mr. Snead said the State Department had been unaware of the reported movement into the western Atlantic until recently.