In Florida's slow-moving Crystal River, huge, lovably ugly manatees are swimming home to the warm-water springs in King's Bay to survive the cold months as they have for countless winters.
About 120 of the endangered species' estimated 1,000 remaining members depend on King's Bay, with its springs that gush water at a constant 74 degrees F., and it is the only place in the United States where the sea cows' numbers are known to be growing.
With man and his motorboat the greatest threat to the air-breathing mammals, a national conservation group known as Nature Conservancy has launched a funding-raising campaign to buy up the 19 small islands in the two-square-mile bay so they can never be developed.
''The manatees congregate in King's Bay because of the warm, clean water with plenty of vegetation for them to eat,'' says Michael Green, Nature Conservancy's Florida director. ''On the coldest days, they stay in the warm springs. If the islands were developed, the only way to get to them would be by boat, and the boats going back and forth would scatter the manatees into colder water where they would die.''
Manatees usually stay close to the surface so they can breathe, and scores of them have been killed in recent years by the propellers of fast-moving motorboats that gouge their backs before the amiable, but slow creatures can dive out of the way. Hardly a living manatee does not bear the parallel scars down its back, marking its encounter with a motorboat.
But the sea cows, which grow up to 14 feet and can weigh as much as one ton, have come under state and federal protection that limits motorboat speeds in areas where they gather during the winter. Recently a US magistrate in Miami ordered a yachtsman to pay $7,000 to the Save the Manatees fund after he refused to obey a Coast Guard order to slow down in a Fort Lauderdale manatee sanctuary.
Nature Conservancy wants to ensure that King's Bay has as few motorboats as possible to give the manatees there a fighting chance at survival.
''The real choice here is that with some consideration in respecting manatee areas there's an excellent chance the manatees will be with us in the future,'' Mr. Green says. ''Without that consideration, they won't be. And there's no way to restore them once they are extinct.''
Nature Conservancy has an option on the islands at a price of $425,000 for the 35 acres they cover. The option expires Dec. 15, and even with actor Burt Reynolds appearing in public-service advertisements asking for contributions for the purchase, the group was still $125,000 short at the beginning of the month.
''We've had 4,000 people donate $300,000,'' Green says. ''But we still need about another 1,000 people to pitch in.'' The World Wildlife Fund now has agreed to match every dollar contributed to an amount up to $50,000.
If the money cannot be raised by the deadline, Green says, Nature Conservancy's national office probably will lend the Florida chapter the difference for two or three months while fund raising continues.
The conservation group, based in Arlington, Va., was created in 1951 to acquire and protect wildlife habitat throughout the US, and Green says it began working quietly about two years ago to negotiate a deal on the King's Bay islands.
Apart from Crystal River, manatees flock to rivers and inlets throughout Florida during the winter, especially to areas close to where electric power plants discharge warm water.
The population has been hit hard during the past few years because of unusually cold winters. Last spring nearly 40 manatee died in the Fort Myers area. Scientists say they believe the deaths were caused by an outbreak of red tide, a poison emitted by a blooming microorganism.
While scientists and conservationists agree they can do little about the weather and the red tide, they say they can do something about controlling motorboats. And they say the King's Bay purchase is one step in the right direction.
''We support it wholeheartedly,'' said David Peterson, the US Fish and Wildlife Service's manatee expert. ''Anything that reduces the number of motorboats in that area is going to be good for the manatees.''