Jan. 16, 2007— -- In the shallow, windswept coves off New York's Long Island, about 40 dolphins have somehow become trapped. Scientists and volunteer rescue groups, trying to get them safely back to sea, wish they understood exactly why the animals get into such trouble.
They have been stranded there for more than a week. Today, the rescuers tried to herd the dolphins back to deep water -- with mixed success.
And this is not the only case so far this winter. "For some strange reason," says Dr. Teri Rowles, the lead marine mammal veterinarian at NOAA's National Marine Fisheries Service, there have been strandings up and down the eastern seaboard.
"These situations are always very difficult," she said. "We'll try to get them to deeper water where they have a greater chance of finding prey."
But why does this happen? Scientists say it is a mystery.
So far, six dolphins have died on Long Island, said Rowles. Several of them became stranded on shore, and the rescuers, unable to move them, had to euthanize the mammals.
Common dolphins -- the species involved in the east coast strandings -- usually eat herring and other fish found near the edge of the continental shelf, a hundred or more miles offshore. In winter, when the ocean gets colder, the fish often move closer to shore, with the dolphins following.
"We're looking at currents and winds, and where their prey are moving," said Rowles. "Is there some disease factor we're finding? Is there something in the environment?"
"All these animals are very social," said Sarah Herzig, stranding coordinator at the Cape Cod Stranding Network, a Massachusetts group that pitches in when cases are reported in other states. "Maybe one dolphin is sick, and the others followed it. There may be one lead animal they're trying to protect."
In the cove near East Hampton, N.Y., Herzig said the dolphins are not, for the most part, in immediate danger. The water is more than six feet deep, so they will not run out of maneuvering room at low tide.
But between them and the ocean, there is a large shallow area that the dolphins clearly do not want to cross. This morning, three dolphins made it out, but there were at least another 15 still trapped in the shallow coves and bays on the Long Island shore.
"We'll try to herd them back out to sea," she said. "But it's always a balancing act. You have to weigh whether they'll just become more stressed when you do that."
The rescuers use small boats, along with "pingers" -- underwater loudspeakers that make noises the dolphins will naturally try to avoid.
NOAA, concerned about human safety on a windy day, urged local boaters not to volunteer in the rescue effort and potentially put themselves in danger.
The rescuers say they feel for the animals, wishing they had an idea what's wrong so that they could prevent such strandings from happening.
"It definitely is a mystery," said Herzig. "This is very unusual."