WELLFLEET, Mass. -- With help from an extremely high tide and an overcast sky, volunteers yesterday rescued 21 of 27 pilot whales that became stranded in the marshes of Chipman's Cove.
Since 1986, only five of the approximately 142 other whales that have beached on Cape Cod are known to have survived, so officials were trying to avoid hasty declarations of success yesterday.
"The whales could still turn around and beach themselves again. We'll have to be on alert for several days," said Vicki Corliss, spokeswoman for the New England Aquarium, one of four
organizations involved in the rescue effort.
"But right now the situation looks very good," she said, looking out beyond the breakwater as the 21 whales, aided by fishermen and rescue workers, swam out of Wellfleet Harbor into Cape Cod Bay.
In deeper waters there, organizers hoped to reunite the whales with two other pilot whales, also believed to belong to their group, that were rescued late Monday after being stranded earlier in the day near Brewster.
Three pilot whales that could not be rescued, beached farther south along the Brewster coast on Monday, were euthanized by New England Aquarium biologists.
Last Thursday, volunteers steered about 45 pilot whales out of shallow water near Eastham, according to members of the Center for Coastal Studies.
A single pilot whale was also discovered last Wednesday on Beach Point in Truro, where bystanders successfully pushed it into the sea. And there have been several reports of other groups of whales swimming
precariously close to shore.
The Wellfleet and Brewster strandings, and three other incidents during the past week, have left marine agents puzzled. "This is probably the biggest mystery we're up against right now: Why is this happening?" Ms. Corliss said.
The most commonly accepted theory is that the whales were looking for dinner. Charles Mayo, a scientist with the Center for Coastal Studies, noted that menhaden, a popular whale food, have been plentiful along the coast, and whales may have come too close to shore and
been trapped at low tide.
Sandy Goldfarb, director of the New England Aquarium, said, "Some people say the hooked shape of Cape Cod upsets their navigational systems, or that parasites affect their inner ears and cause them to get confused."
Still others attributed the beachings to pollution or a strange instinct that makes the whales want to die.
But everyone agreed that the Wellfleet rescuers, at least for the moment, had achieved a rare success.
"To have them swim off at high tide is very unusual," said Stephen Vest, vice president of the International Wildlife Coalition.
Workers arrived quickly on the scene following a 5:30 a.m. report of the mass beaching, Mr. Vest said.
They covered the whales with mud to keep them cool and protect them from the sun, sprinkled them with water, stroked them and tried to comfort them -- a task made easier by the cool, overcast weather.
Six of the 27 stranded whales died natural deaths during the course of the day. Biologists believe they died from the stresses of life out of water.
When the tide came in, rescuers tried to "walk" the animals in shallow water, getting them to use their muscles while keeping them upright.
They selected some of the healthiest whales, hoping to save at least a few by transporting them to deeper water in slings. "But while that was going on, the others started to get control and moved out on their own," helped by a tidal surge at midmorning, Mr. Vest said.
Then rescuers transported the healthiest, noisiest whales to key points along the route out of the cove, "scattering them like a trail of crumbs," so the vocalizers would call to the others, according to Gregg Early, the aquarium's associate curator of animal care.
Local fishermen and rescue workers then formed a barrier behind the whales, beating with paddles against the sides of their boats to discourage them from returning to the cove.