Every year in late July, about 30,000 boats descend on this tourist mecca carrying tens of thousands of scuba divers who scour the coral reefs in search of tasty spiny lobsters to catch and eat.

Government officials say the two-day frenzy nearly doubled the monthly reports of boats ramming fragile coral heads or grounding on delicate sea grass compared with the month before. And while no one has an exact figure, researchers estimate the fishing fest took 80 percent of the legal-size lobsters in several Keys habitats.

"It's a consumptive ritual," Phil Frank, project leader for the Key West National Wildlife Refuge, said of the underwater wreckage.

The fate of the slow-growing corals in the Keys is just one small example of the pervasive damage being done to the world's oceans, damage that has been documented by a rapidly accumulating library of studies and reports. The reports -- from governmental, private and academic sources -- all say the same thing: The seas are much worse off than they were just a few decades ago. Oceans across the globe are showing signs of strain in dramatic ways, including declining fish stocks and polluted waters.

Inside and outside the government, a conviction is taking hold that policymakers need to act quickly to avert the looming crisis. Bush administration officials and lawmakers are drafting new rules and changes to the federal bureaucracy to protect fish species, improve water quality and restore coral reefs. Some of these plans were unveiled last month when the presidentially appointed U.S. Commission on Ocean Policy issued its final report to Congress.

"Ocean conservation is poised to become the next global warming issue," said Gerry Leape, who runs the marine conservation network for the National Environmental Trust. "The science is settled. The debate can move on from whether or not there is a crisis to what to do about it."

Scientists and policymakers point to a variety of ominous signs. Ninety percent of the world's large predator fish -- those at the top of the food chain -- have disappeared over the past 50 years, two Canadian scientists reported last year in a widely publicized study. At least a third of the fish stocks that the federal government monitors are overfished, officials say, and the status of hundreds of other species is unknown. The motor oil dropped on American streets ends up in the oceans at the rate of 10.9 million gallons every eight months -- the equivalent of the Exxon Valdez spill. And the dead zone in the Gulf of Mexico -- an area the size of Connecticut where high nitrogen levels kill all marine life -- expanded again this summer.

"There is a consensus that our oceans are in crisis and that reforms are essential," a massive study funded by the Pew Charitable Trusts concluded last year.

James L. Connaughton, who is President Bush's top environmental adviser as head of the White House Council on Environmental Quality, said the seas sustain "our economy, our environment and our society."

"Restoration, wise use and conservation of the oceans has come to the forefront of environmental priorities, not just for the nation, but for the world," Connaughton said. "There's a massive bipartisan and regional consensus toward embarking on a new generation of progress."

For centuries, the various studies note, Americans have treated coastal waters as theirs for the taking, seeking bounty with little government oversight. Fishing boats trawled and trapped at will, oil companies built huge rigs to tap offshore resources, and cruise ships crisscrossed sensitive habitats so tourists could gawk at marine life.

"It cannot be viewed as the Wild West anymore," said retired Vice Adm. Conrad C. Lautenbacher Jr., who heads the National Oceanic and Atmospheric Administration. "There need to be some sort of property rights. That sort of cultural change is very hard."

He and others note that U.S. territorial waters are the country's largest public domain: Spanning nearly 4.5 million square miles, they are 23 percent larger than the nation's land area. Commercial and recreational saltwater fishing is worth $48 billion a year, and weather- and climate-sensitive industries, which are heavily influenced by the ocean, account for $3 trillion, or more than one-quarter of the country's gross domestic product.

Yet the seas command relatively little attention. Ninety-five percent of the globe's oceans remain unexplored below the surface, and donations to environmental groups that focus on marine issues are 5 percent of the amounts that go their terrestrial counterparts. The nation has marine sanctuaries, the rough equivalent of national parks on land, but most Americans have never heard of them.

Elliott A. Norse, president of the Marine Conservation Biology Institute in Redmond, Wash., said much of the devastation being done to the oceans has gone undetected. The Gulf of Mexico's population of oceanic white-tipped sharks has declined more than 99 percent since the 1950s, but no one noticed until 2003. The eel grass limpet, a snail that used to be ubiquitous on the New England coast and Canada's Atlantic coast, went extinct in 1929, but its demise did not come to public attention until 1991.

"Nobody's out there looking," Norse said. "Nobody's out there measuring what we need to measure."

Despite the commissions and studies, "this is a battle between people who care about the oceans and those who are at best disinterested, or at worst, exploiters," Steven Miller, director of the National Undersea Research Center at the University of North Carolina at Wilmington, told ocean experts in Key West in August. "It's a war, and we're losing."

But with calls for action mounting, policymakers are beginning to pay attention. The Commission on Ocean Policy, a 16-member panel, called on Bush in April to appoint a special assistant for oceans issues and to make broad policy changes. The Pew Oceans Commission, a privately funded group that issued its own set of recommendations in May 2003, recommended retooling federal fisheries management and making NOAA independent of the Commerce Department.

Last month, the Senate Commerce Committee endorsed legislation to set a new national oceans policy featuring some of the commissions' recommendations, such as making NOAA more independent. Ted Morton, federal policy director for the marine protection organization Oceana, called the vote "a welcome first step in ocean management reform."

Connaughton said the administration is also reexamining how to govern the seas.

"We're not waiting for anything," Connaughton said. "We are past the ignoring stage. We have collectively moved over the past three years toward action."

The administration has proposed new water quality regulations for beaches near ocean waters and the Great Lakes, stricter curbs on sulfur dioxide and nitrogen oxide emissions from marine diesel engines, and new zoning restrictions in Florida's Dry Tortugas National Park, he said. But some new protections that have long been under consideration have yet to materialize: In 1994 the United States signed the U.N. Convention on the Law of the Sea, which would create new international standards for protecting marine mammals and fisheries as well as curbing marine pollution, but 10 years later it has yet to be ratified by the Senate.

Experts say existing and proposed national and international measures do not go far enough to address the four major challenges that threaten the oceans: overfishing, incidental bycatch, habitat destruction and pollution.

The sharp decline in fish stocks over the past few decades is one of the clearest indicators of trouble. The list of species whose numbers have plummeted -- some of them edging toward extinction -- is lengthy, from New England cod to California's white abalone. Ellen Pikitch, executive director of the Pew Institute for Ocean Science at the University of Miami, said we may witness "the end of wild fish fisheries in a matter of decades."

In many cases U.S. fishermen have gotten caught in a vicious circle, in which they take so many fish there are not enough left to perpetuate the species. This depletes fish stocks, which in turn makes it even harder to catch enough to turn a profit.

For consumers, the depth of the crisis is obscured, in part because of the rise in fish farming and the fact that some relatively common fish are being mislabeled and sold as valuable but increasingly scarce species, such as red snapper.

Found in the Gulf of Mexico and the western Atlantic, red snapper has been overfished since 1988. For captain Ronald Waters, who has spent a quarter of a century fishing in the Gulf, the outlook is grim. He estimates that half the fish he pulls up are too small to sell, but by the time he throws them back they are dead.

"I need fish there to earn my living," Waters said in an interview. "As the stock's going down, it's taking us a lot longer to catch fish."

Bycatch -- unwanted fish that are hauled in by mistake -- account for more than 25 to 30 percent of the total world catch, which means 60 billion tons of fish is being caught and thrown dead into the oceans. Although NOAA regulators have doubled the number of observers it has on ships in the past four years to monitor bycatch and other fishing practices, they only covers 42 of the 300 U.S. fisheries.

Bottom trawlers that scour the ocean floor pose another serious threat to marine ecosystems, given that 98 percent of known ocean animals live on the bottom. The trawlers' giant nets -- some of them wide enough to accommodate two Boeing 747 jumbo jets, bring in massive amounts of fish, but they decimate ocean-bottom habitats in their path.

The result is like forest clear-cutting, but on a much larger scale, advocates and researchers say. Worldwide nearly 40,000 square miles of forest are clear-cut each year, Norse said, an area the size of Indiana or Kentucky. By contrast, nearly 6 million square miles of ocean floor are swept clean by nets every year, an area twice the size of the lower 48 states, he said.

The impact of pollution is even broader, though it is difficult to gauge and even harder to regulate. Runoff from agriculture pours nitrogen into the seas, which in turn spawns algae blooms that deprive marine creatures of oxygen. Nancy Rabalais, chief scientists for hypoxia research at Louisiana Universities Marine Consortium, said agriculture accounts for 50 percent of the nitrogen that deluges the Gulf of Mexico's dead zone.

Lawmakers have proposed revamping the nation's marine management system based on the recommendations of the U.S. Ocean and Pew commissions, and advocates say they may now have their best chance in decades to institute new protections for the seas. It is less of a partisan issue than other environmental questions: Bush administration officials are in discussions with conservation groups, which also see Democratic presidential candidate John F. Kerry as a potential ally.

"This is a seminal moment," said Roger T. Rufe, president of the Ocean Conservancy.

"It's just like the Grand Canyon or Yosemite or other wonderful areas," said Richard Grathwohl, a third-generation charter boat captain. "We're loving it to death."

A spiny lobster sticks out from below live coral off Key West, Fla. Scuba divers descending on the area in late July for a massive lobster catch often damage the fragile, slow-growing coral.