Rescuers guided eight distressed dolphins back into open water on Tuesday, a week after several of the animals became stranded in a shallow cove off Long Island, New York.
About 20 common dolphins wandered into the cove-like Northwest Creek near East Hampton, New York, last week, said Chuck Bowman, president of the Riverhead Foundation for Marine Research and Preservation, who has been involved in the rescue efforts.
The dolphins were thought to have followed fish through a narrow opening that allowed boats into and out of the cove.
Up to 80 rescuers and 10 marine biologists have worked to lure the dolphins back out toward the Atlantic Ocean.
"After working all day we got about eight dolphins out into the open bay waters, giving them a chance to survive," he said. "But about four are still left in the creek area." Six others have died, he said.
Above-average winter temperatures in the Northeast United States have caused some marine life, including dolphins, to linger closer to the shore than usual, Bowman said.
"Normally (the dolphins) would be far offshore feeding on Atlantic herring and mackerel," he said. "But we believe because of the warmer weather and temperatures the fish moved closer to the shore and the dolphins followed," he said.
Rescuers banged pipes on boats and rang underwater "pingers" to force the dolphins out of the shallow waters.
"They had to have been in stress because they had no food and were not in their natural habitat," Bowman said.
Rescuers were to try to free the remaining four dolphins on Wednesday.
In a separate incident, eight common dolphins were found beached on Sunday in the Boston suburb of Quincy, the first mass stranding that scientists could recall in Boston Harbor.
Thirty-one dolphins and a pilot whale have been stranded along the Massachusetts coast since the start of the year. Some had brain deformities or chronic diseases.