Rescuers reported some success Tuesday in their attempts to lure a dozen or more wayward dolphins out of a shallow cove between the twin forks of eastern Long Island, nearly a week after the spunky mammals were first seen frolicking in the waters north of East Hampton.
The common dolphins — no one is sure exactly how many are out there — became stranded last week in the Northwest Harbor cove, attracting spectators and marine biologists who feared for their safety. Six have already died.
As many as nine dolphins were chased through the narrow inlet and headed for safer waters on Tuesday, and the effort to rescue about three remaining animals was expected to resume Wednesday, said Charles Bowman, president of the Riverhead Foundation for Marine Research and Preservation.
Although a rare occurrence on Long Island, dolphin strandings are an annual event in places further north, including Cape Cod, said Tony LaCasse, a spokesman for the New England Aquarium.
"Since late December, there has been a series of strandings on Cape Cod," LaCasse said. "We have a mass stranding or two every winter; last year there were over eight."
Unlike the more popular bottlenose, or "Flipper" type dolphins found in southern waters, this species — usually found year-round off of Long Island and into New England — are the "common" and "white-sided" varieties. They are usually six or seven feet long and weigh about 250 pounds or more, LaCasse said. Ordinarily, the dolphins stay between 30 and 80 miles off shore, he said.
The "common dolphins" off East Hampton appeared to be balking at traveling through a shallow inlet separating them from the larger and deeper Gardiner's Bay. Rescuers made their first attempt Sunday to herd them out of the cove using devices called pingers — which emit a high-frequency sound — and revving small boat engines, to direct the animals to safety.
William Wise, director of the Living Marine Resource Center at Stony Brook University, said the dolphins may have chased a school of herring, mackerel or squid into the cove during a high tide. Then their internal defenses prevented them from traveling back through an inlet they consider too shallow.
Because of concerns that the animals were becoming "stressed," rescuers let the dolphins rest on Monday before returning to the waters on Tuesday, Bowman said.
Scientists tended to doubt speculation that the dolphins moved toward the coastline because of the unusually warm winter that Northeasterners have been experiencing.
"They are fairly adapted to cool water," Wise said. "The difference in water temperature is not that great. It's more of a question of disorientation in shallow water and a lack of food; that's a greater threat."
LaCasse, of the New England Aquarium, said scientists were first focusing on rescuing the dolphins before they investigate exactly why they became lost.
"Dolphins are extremely social and can panic just the way people panic; they are very bright," LaCasse said. He said whether a warm January contributed toward their wayward turn toward shore "is a complex question involving ecosystem dynamics."