The director of the Martha's Vineyard Shellfish Group said there may be good news for a crop of about a million baby oysters that were threatened by an oil spill in the Edgartown harbor early this week.

"I don't want to say that we are out of the woods entirely, but the oysters may survive," said shellfish group director Rick Karney on Wednesday this week.

Mr. Karney said he hopes the incident will serve as an important wake-up call for the Vineyard on the potential for disaster in shellfish-rich ponds and harbors that are populated heavily by recreational boaters in the summer months.

"Some people may say we cried wolf, but the truth is this was a wake-up call and a dry run, if you will. Because what do we do the next time this happens?" Mr. Karney said.

Early Monday an oil spill of unknown origin fouled the water in the outer Edgartown harbor and was sucked into a shellfish hatchery owned by the shellfish group on Chappaquiddick.

Heavy oil suspended in the water was also reported about a half-mile east of the hatchery on the north shore of Chappaquiddick.

The fouled water left strong fumes inside the shellfish hatchery and Mr. Karney said at the time he believed the contaminated water had killed all the oysters in the hatchery.

Investigators from the U.S. Coast Guard Marine Safety Office in Providence, R.I. were dispatched from a field station on Cape Cod to survey the outer harbor, but by the time the investigators arrived they found no oil in the water. Water samples containing the oil, taken by both the Edgartown harbor master and Mr. Karney, were taken back to the Cape by the Coast Guard for analysis.

Mr. Karney took a sample of the baby oysters to the Marine Biological Laboratory in Woods Hole, and he said early analysis showed that the oysters may survive.

"We will know in about a week. Each day that goes by with survival is good news, and the first 24 hours are probably critical. If the die-off was going to be massive, it would be within 24 hours," Mr. Karney said.

He said oysters are more resilient than other shellfish. "They are known for their ability to shut down tightly if something is being deposited on them, and that might be one of the reasons why the survival was better this time. I would have put money on the fact that we were going to have big losses," said Mr. Karney, a veteran marine biologist who has been the director of the shellfish group for 26 years. The group also has a solar hatchery on the Lagoon Pond in Vineyard Haven.

Mr. Karney said a quick response and thorough rinsing of the oysters by his assistant on Monday morning when she detected the strong fumes in the water may also contribute to the survival of the oysters.

A state marine biologist said last week that oil suspended in the water can be extremely toxic to shellfish beds, especially juvenile shellfish.

The Edgartown harbor is known for its productive shellfish beds, from the bay scallop beds in the outer harbor to the quahaugs, softshell clams and more bay scallops in upper Katama Bay. Mr. Karney said there are currently five commercial shellfishermen who have bottom grants to culture oysters in the area of the harbor known as the narrows. The bottom grants support floating nurseries with about a million adult oysters, Mr. Karney said. The outer Edgartown harbor also flows into Cape Pogue Pond, a rich resource for bay scallops and quahaugs.

Shellfish records published in the Edgartown annual town report last year show that the commercial shellfish catch in Edgartown was valued at just over $1.1 million. In 2001 commercial shellfishermen landed 678 bushels of clams valued at $61,120; 1,726 bushels of quahaugs valued at $135,810; 448 bushels of oysters valued at $17,920, and 9,893 bushels of scallops valued at $890,370. Also 555,000 pounds of conch were landed in Edgartown at a value of $385,000.

Mr. Karney said the oil spill incident in the outer harbor last week raises a key question.

"A million adult oysters, softshell clams, hardshell clams and scallops. The laws are all out there [that prohibit discharge from boats]. The question is do we need more enforcement and more education. Should we try to convene some sort of discussion - what can we do to prevent this?" he said.