GAINESVILLE, Fla. (January 6, 2003 7:53 a.m. EST) - Florida's endangered manatees could be further threatened if the state's aging coastal power plants are closed, eliminating the heated water discharges that the lumbering mammals use for warmth in the winter, scientists said.
Manatees are vulnerable to the cold found in some parts of the state because they need water temperatures of at least 68 degrees to survive. The marine mammals spend the winter near natural springs, where temperatures often hover around 70 degrees, or power plants located near rivers or bays.
Aging coal-fired generating stations use natural water sources to cool their power systems. Once circulated through the plants, water is returned to its source about 15 degrees warmer.
"The real problem for manatees is deregulation of power," said Bob Bonde of the Sirenia Project in Gainesville, a manatee research center for the federal government. "Without the power plants, a lot of manatees are going to die."
As the power industry is deregulated, aging plants could be closed or upgraded to use cooling methods that don't require water, Bonde said.
"These plants going off-line before some resolution to the manatee situation is certainly cause for concern," said Ron Mezich, a biologist with the Florida Fish and Wildlife Conservation Commission.
Powerboat accidents are often considered the most imminent risk to Florida's estimated 3,500 manatees. Watercraft-related manatee deaths reached a record annual high of 93 last year, according to the Save the Manatee Club of Maitland.
State regulators are considering changing the manatee's designation from endangered to threatened, indicating they are now less imperiled. Critics say that move could loosen rules on dock-building and powerboat speed zones.
But federal and state biologists say the greatest threat to the manatee may be its growing reliance on the artificial warm water sources as pollution and increased consumption cause fresh water sources to diminish.
When a Jacksonville water-cooled power plant closed two winters ago, the state had to relocate some manatees and at least five were found dead of cold stress, said Jamison Smith, a researcher with the state wildlife commission.
He said a number of older, more-experienced herds headed south in search of warmer water.
"Typically, adults with calves use the warm-water power plants as a stopping ground," Smith said. "The animals that are most susceptible are the juveniles. We're hoping that they will figure it out on their own."
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