Stakes are high in push to drill for oil off California. Areas of greatest promise lie in rich fishing grounds or sensitive habitats

In the contentious debate over where to ban oil and gas drilling off the California coast, the stakes are high. Much of the state's coastline is at issue, including its grandest unspoiled vistas, its richest commercial fishing grounds, and its most sensitive habitats for endangered species.

But so are what the oil industry now considers its most promising offshore oil and gas prospects in the continental United States. The American Petroleum Institute's (API) member companies estimate that as much as 20 to 25 percent of all existing US reserves may lie in federal waters off California.

The entire continental shelf from the Santa Maria River (just south of San Luis Obispo) north and parts of the shelf off the southern California coast are closed to drilling under congressional moratoriums. But they expire at the end of October.

The current negotiating, chiefly between Interior Secretary Donald P. Hodel and congressmen from California, is over what happens next. Which offshore tracts should Interior open for lease-sale to oil companies?

A tentative pact negotiated this summer fell apart. Mr. Hodel backed away from the pact after he realized that it would only offer access to about 5 to 7 percent of the oil estimated to be in the moratorium area. Hodel

In response, 29 members the California congressional delegation Thursday introduced legislation to both houses of Congress to enact that tentative agreement.

The oil industry especially wants access to three key basins -- Santa Cruz, Bodega Bay, and Point Arena. The US needs to develop these oil fields to keep imported foreign oil at about a third of US consumption, says Steve Chamberlin, director of exploration at the API. Without it, he predicts, Americans will be importing fully half their oil in five to 10 years.

Estimates of how much oil is off the California coast vary widely. The Interior Department now guesses between 1 billion and 3 billion barrels of oil equivalent (which includes natural gas). API member companies suspect 5 billion to 10 billion barrels are there -- a whopping addition to this country's 28 billion barrels of proven domestic reserves.

``Until you know what's there, you don't have a basis for weighing the environmental risks,'' says Mr. Chamberlin, summing up the oil industry's basic position that specific concerns are always negotiable with both the state and local communities.

On the other side are Californians concerned that oil development will transform scenic coastal communities into heavy industrial centers, pollute the air and water, disrupt rich fishing grounds, kill endangered sea otters, and mar the horizon with steel platforms.

``We think it's bad national policy and bad local policy,'' says Gary Patton, Santa Cruz county supervisor.

If oil were produced off the Santa Cruz coast, he estimates, there would be one major spill of more than a thousand barrels during the 20 or so years of production, air pollution would grow significantly worse in an area that already is not meeting state standards, and a major onshore industry would grow where there is no industrial infrastructure.

The decision is not entirely in federal hands. Hodel determines which lease-sale tracts can be auctioned. But the California Coastal Commission must approve any well-drilling -- even exploratory -- as being consistent with state plans for the coast. The US commerce secretary can then overrule the commission, leaving lawsuits as the arbiter of last resort.

The coastal commission's general position, says spokesman Jack Liebster, is that the coast from the Santa Maria River north is not worth the risk of developing.

The economic risks are chiefly to tourism and fishing. Big Sur and the Mendocino coast are major tourist areas, attractive for their unspoiled grandeur, onshore and off. Oil drilling would pose several kinds of conflicts in rich fishing grounds, such as the Eel River Basin, Shelter Cove, Point Arena, Cordell Bank off from San Francisco, Monterey Canyon, offshore Morro Bay, and areas off Orange and San Diego Counties.

Zeke Grader, executive director of the Pacific Federation of Commercial Fishermen, notes that oil drilling off northern Santa Barbara County has already cost fishermen there 40 percent of their trolling grounds -- lost to drilling platforms and the guy cables that spread around them, the net-tearing debris that drilling contractors dump on the ocean floor, and pollution from the heavy metals and diesel oil in drilling muds.

An important environmental concern along the central coast is the endangered sea otter. Oil fouls the fur's capacity to keep the otters warm in the cold water. One oil spill, says Carl Pope of the Sierra Club, ``could wipe out the entire species.''