WASHINGTON, D.C.: Faced with the collapse of Atlantic fisheries and disturbing declines in the Pacific, the Clinton Administration said Friday it would impose strict regulations that could close many areas to fishing and significantly alter fishing practices in U.S. territorial waters. The cost has been severe. The cod populations of the Grand Banks have fallen 95 percent. Populations of breeding-age Atlantic bluefin tuna have fallen more than 90 percent. In many places, the losses of commercial fish stocks have been catastrophic, and in the last decade tens of thousands of fishermen have been forced to abandon their boats. A spokeswoman for the National Oceanic and Atmospheric Administration said that preserving fish habitat -- and therefore the industry -- was "one of the top national priorities." Regional fishery councils will have to identify "essential fish habitat" and the pressures that threaten them. The guidelines are part of a law sponsored by Republican Senator Ted Stevens of Alaska and signed last year by President Clinton. Stevens has promised to use his position as chair of the Senate Appropriations Committee to fund the program. There doesn't seem to be much time for failure. Better technology drove the world catch from 20 million tons in the 1950s to more than 85 million tons by the end of the 1980s, but the harvest has been shrinking throughout this decade. The declines are not simply a result of overfishing, but also of practices that destroy the ocean-floor habitats that feed and protect schools of commercial fish. Factory trawlers scare up schools by dragging heavy chains over the sea bottom, uprooting aquatic plants and killing coral and shellfish. Migrating fish, such as salmon, are caught before they can spawn, thus killing their progeny as well. This one-two punch has contributed to the endangerment of many species, even those that are not pursued for their food value. The good news? Once the damaging practices end, depleted fisheries have shown a surprising capacity to revive.