The rocky seaward shore of this small coastal island is called the "Wild Coast." Protected as a nature preserve, it is largely populated by gulls and cormorants, a place where older residents cast their lines for sea bass and younger ones surf and jog.

Today, helicopters soared overhead and surveillance teams clambered along the rocks as authorities on the Wild Coast and other areas along France's Atlantic coastline began preparations for what could become an ecological crisis. Barring a miracle, a tide of viscous, heavy oil from a shipwrecked tanker will flow onto the beaches, rocks, fish farms and ports of this region as early as Saturday.

Since the Maltese-registered Erika broke in two and went down in rough seas 65 miles off the coast of Brittany Dec. 12, spilling 2.8 million gallons of oil, this region has expected the oil to come ashore. Currents and winds, which had been pushing the oil slick southeast along the coastline, have shifted and are now driving it toward land.

"I like to fish here, but the oil could degrade this coast for years. We'll have a black coast," said Daniel Turbe, a builder by trade and a fisherman by hobby, as he watched a police helicopter land on a plateau above the coastal rocks.

The amount of oil involved is far smaller than that of a 1978 shipwreck, in which the Amoco Cadiz poured 68 million gallons of light oil onto 100 miles of the Brittany coastline north of here. In addition, the oil from the Erika, because it is of a heavier variety, contains fewer toxic components, said Bruno Rebelle, director general of the environmental organization Greenpeace France. It will arrive along the shores in scattered clumps, not as an all-covering liquid. But, Rebelle said, that heaviness means the oil fragments will stick to anything they touch. "It will asphyxiate all forms of life, anything it touches--algae, micro-fauna, micro-flora," he said.

Eight tugboats have been trying to pump the oil out of the water for more than a week. The first try failed because the pumps could not suck up the thick, black goo. After 11 days mixing with cold sea water, the oil now is nearly the consistency of chewed chewing gum, authorities say. It is fragmented into dozens of separate slicks.

Some 170 soldiers and civilian workers will spend Christmas on the island preparing for a massive cleanup effort. More than 2,000 personnel, using an action plan designed after the Amoco Cadiz spill, are mobilized along a 125-mile stretch of coastline.

It is not clear how successful they can be, however, and already environmental damage is beginning to show. Fishermen said they are seeing dead gulls. Jean Noury, a fishermen charged with collecting oil-covered birds on the island and taking them to the mainland to be cleaned, said he had received 11 by lunchtime today, compared with five Wednesday and four the day before.

Because the oil is so heavy, the birds are not completely covered, he said. Most affected are the diving birds, who catch their prey underwater. They die either from the toxic effects of the oil or from starvation because they cannot dive.

The blame game is beginning as well. Although the cause of the Erika's wreck is not clear, the captain of the ship--the entire crew of 27, all Indian nationals, was saved--was placed under investigation and put in preventive detention. He was released Wednesday.

Politicians are calling for inquiries and blaming the company whose oil was being shipped, TotalFina. Philippe de Villiers, a powerful national politician who heads the regional government, has called for a boycott of TotalFina gasoline.

Residents of this tiny island, with a population of 4,800 in winter and about 30,000 in summertime, were hoping that the latest weather forecasts would prove true. The slick, at first thought to be headed for Ile d'Yeu by Christmas, now is predicted to hit north of here, perhaps at St. Nazaire, then reach the island Monday.

This is a bitter time for the 200 or so affected fishermen of the Ile d'Yeu to be reeling in their equipment. Prices for the fish they specialize in have in some cases doubled during the Christmas season, but they cannot share in the profit.

"We had that spill two decades ago, and they're still not capable of dealing with this," Naud said. "They can put a man on the moon, but they still can't clean up the oil."