The underwater world of Anacapa Island's north shore is a museum and cathedral, a place to worship the dazzling array of marine life that once filled the sea, but now only exists at enclaves like this one.

Clusters of spiny lobsters skitter into sea caves. Rocks bristle with softball-sized sea urchins and rare pink abalone. Sheepshead and kelp bass prowl unmolested by hook or net.

The reason life flourishes here is that every turban snail and starfish, each scallop and sea anemone is protected. This 37-acre reserve is one of a handful of small don't-fish, don't-take, don't-even-think-about-it zones on the West Coast.

But as more and more fishing fleets employ increasingly sophisticated technologies to locate fewer and fewer fish, policy-makers are contemplating a radical solution that only a few years ago was unthinkable: posting no-fishing signs along stretches of California's 1,100-mile coastline.

The first step may be taken at this archipelago off Ventura County, where officials are considering a proposal to dramatically expand no-take zones in the national park. Up to 20 percent of the islands' waters, or 25,000 acres, could be placed off limits to fishing -- four times more than currently receives such protection throughout California.

Although the proposal has ignited intense debate, the concept of no-take reserves is endorsed by environmentalists, the National Park Service, many scientists, Gov. Gray Davis' secretary for natural resources, the state Fish and Game Commission and even some fishing groups. A bill before the Legislature would require that fishing-free sanctuaries be established along the shoreline in three years.

"This is strong medicine. It's a huge change from the traditional way of doing business," said Gary E. Davis, marine biologist at Channel Islands National Park.

The idea has already caught on around the world. Nations that have closed sections of their coasts to fishing boats include South Africa, Belize, Chile and the Philippines.

In Australia, about 2 percent of the Great Barrier Reef is off limits. Ecuador's reserve will encompass one-third of the waters surrounding the Galapagos Islands. New Zealand has established 14 reserves, and 35 more are under consideration.

That no-take refuges have gained serious consideration is tacit acknowledgment that the era of an ever-bountiful ocean is fast nearing an end. Fifty years ago, half the world's prime fishing waters and stock were largely untapped. The arrival after World War II of the factory fishing boat, with its miles-long nylon nets and advanced marine electronics, has taken nearly as devastating a toll on fish as the Sharps rifle did on the buffalo a century ago.

From horizon to horizon, two-thirds of the Earth's major fishing areas and stocks are now exhausted or seriously depleted, according to the Food and Agriculture Organization of the United Nations. In the United States, 80 percent of 191 commercial fish stocks are overexploited, the National Research Council says.

Other factors contributing to the declines include pollution, wetlands losses, poaching and invasive species.

In the past, wildlife managers relied upon size and catch limits and fishing seasons to preserve fish stocks. Those strategies are now widely viewed as failures.

"We've long thought oceans to be so vast and so infinite that nothing we could do would make much of a dent in them, but we're learning very quickly this mind-set has been misdirected," said Jane Lubchenco, a zoologist at Oregon State University and former president of the American Academy for the Advancement of Science. "What we are doing now is not working. We need to do things in a very different way. I view (no-take reserves) as one of the most powerful things that we can and should do immediately."

At first blush, fish along much of the California coast appear to be well-protected from hooks and nets, trawlers and traps. From Crescent City to Chula Vista, 104 "marine protected areas" cover nearly one-fifth of the coast.

They restrict everything from dredging to boat traffic. But there is wide agreement that they have failed to protect fish stocks. Like a storehouse with the gates open, virtually all of the California coast is in fact open to fishing.

Only nine of the 104 protected areas are completely off limits to fishing.

The protected areas are such a morass of overlapping and contradictory regulations that the state Department of Fish and Game has spent the last year trying to figure out how they fit together and what rules govern them. They were created over decades by various agencies for different purposes.

Proposals to close parts of the ocean to fishing have sparked intense debate from Ventura to New England, from Alaska to the Florida Keys. A few refuges have been established; some of the largest are at Key West, Fla.; Georges Bank off Cape Cod and in Puget Sound, Wash.

The strategy is a familiar one on land, where national parks, some private lands and game reserves were set aside to preserve everything from elk to birds. Said Warner Chabot, director of the Pacific region for the Center for Marine Conservation: "We have wilderness areas in mountains. This is trying to apply wilderness areas to the ocean."

"We are looking for much better marine management. Unless we make some changes, our kids and grandkids aren't going to have any fish out there," said Tom Raftican, president of United Anglers of Southern California, the state's largest sport-fishing group.