Aging power plants seen as important to sea cows
Published: Sunday, January 5, 2003 at 6:01 a.m.
Last Modified: Sunday, January 5, 2003 at 12:33 a.m.
Two miles from Three Sister's Springs manatee sanctuary, steam spews from Progress Energy Florida's Crystal River power plant.
FYI: Power plants and the manatees
Each winter, thousands of Florida manatees congregate in the warm waters that spill from the state's coastal power plants. But as the aging generating stations break or are replaced by cheaper, more efficient technologies, marine biologists fear the sea cow's reliance on power plants could be its undoing. Here is a sampling of Florida's power plants that manatees have frequented in recent winter months. County and wintering population numbers in parenthesis:
"We're going out into their homes," said Marty Senetra, 42, captain and divemaster on an early morning snorkeling tour at the springs last month. "This is their world."
Their world, however, may be in jeopardy.
Vulnerable to cold, Florida manatees have for years wintered near natural springs, where temperatures often hover around 70 degrees, or power plants, where warm water has been discharged for decades.
But with many of the state's power plants aging and scheduled for upgrades, decommission or replacement by cheaper, more efficient technology, scientists say the biggest threat to the endangered sea cow may be their dependence on these artificial heat sources.
"A quick loss of a power plant could have pretty dramatic effects on large numbers of manatees," said Ron Mezich, a biologist with the Florida Fish and Wildlife Conservation Commission. "These plants going off-line before some resolution to the manatee situation is certainly cause for concern."
To be sure, powerboat strikes - often considered the most imminent risk - still present dangers to the slow-moving manatee.
In 2002, for instance, watercraft-related manatee deaths reached an all-time high of 93, according to Save the Manatee Club of Maitland. The number of annual boat collisions isn't likely to decrease in the near future, either, as new boat docks and marinas continue to sprout in southwest Florida, and state regulators consider changing the manatee's state designation from "endangered" to "threatened," a move critics argue could loosen rules on dock-building and powerboat slow-speed zones.
But federal and state biologists say the greatest threat to the manatee may be its growing reliance on the artificial water sources.
Manatees have been congregating near Florida power stations since the late 1940s. Located on rivers or bays, aged coal-fired generating stations like the one in Crystal River use natural water sources to cool their power systems. Once circulated through the plants, water in these operations is returned to its source, typically 15 degrees warmer than when originally removed, industry officials said.
For the wintering herbivores, which require water warmer than 68 degrees to survive, heated thermal outflows from coastal power plants provide a much-needed respite from colder waters.
Statewide, more than a dozen power plants on the Gulf and Atlantic coasts spill warm water, attracting manatees during their winter migration.
In Hillsborough County, for example, 200 to 300 West Indian manatees consistently gather near the TECO Big Bend Power Plant during the winter months, Mezich said. To the east in Brevard County, both the Reliant Energy and Florida Power & Light plants have offered manatees warm-water havens for years.
And in Citrus County, dozens of manatees have been spotted in waters near the generating station in Crystal River this year, although natural springs near Kings Bay like Three Sisters provide the majority of the area's annual migrating needs. In the summer months, manatees travel as far north as Virginia.
But available freshwater sources - in Crystal River and elsewhere - are shrinking, threatened by pollution and increased consumption, some experts say.
Adding to the problem, deregulation of the power industry, which could result in the construction of newer plants that rely on nonwater sources for cooling, and the eventual breakdown of power stations, many of which are 30 or 40 years old and whose futures are uncertain, could reduce artificial wintering sites, scientists say.
"The real problem for manatees is deregulation of power," said Bob Bonde of the Sirenia Project in Gainesville, a manatee research center for the U.S. government. "Without the power plants, a lot of manatees are going to die."
No one knows for sure how the state's 3,500 manatees would respond to widespread plant closures.
Jamison Smith, a marine research associate with the state Fish and Wildlife Conservation Commission, said a plant closing in Jacksonville two winters ago forced the state to relocate some of the animals, and at least five manatees were found dead in Duval County waters, victims of cold stress.
But despite the deaths and relocations, Smith said a number of older, more-experienced migratory herds did head south in search of warmer water, a sign he said suggests that the removal of a regional warm-water source like a power plant wouldn't necessarily spell disaster.
"Typically, adults with calfs 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."
Disappearing power plants and increased boats strikes are not the only threats to the endangered manatee, however.
Some experts also fear that an increase in annual visitors to winter sanctuaries could put additional strains on already taxed populations.
Between 1980 and 1995, the number of people interacting with marine animals increased by 63 percent, according to a U.S. Department of the Interior study. Last year, in the Crystal River area alone, more than 100,000 people ventured to swim, dive or boat alongside the herds, another study found. And while state and local regulators have placed some controls on where the public may interact with the animal, cordoning off "no access" areas, the annual growth has occurred virtually unchecked.
"It is certainly a growing type of ecological industry," said Bonde, the Sirenia Project biologist.
Bonde added that increased human-manatee interactions could be a detriment to the endangered mammals, potentially damaging habitats or affecting reproduction, and a recent Texas A&M University study found that increased visitor harassment of Crystal River manatees in recent years has resulted in negative impacts on manatees, ultimately influencing "the fitness of the populations."
Still, despite the many threats facing the manatee - from power to people - snorkelers on board Senetra's pontoon flotilla last month sounded convinced their curiosity wouldn't become detrimental.
"I think it's good that we went out," said John Wilt, visiting Crystal River from Chicago with his wife and two daughters. "My kids, now that they know what the manatees are, are going to be more respectful."
Greg Bruno can be reached at 374-5026 or greg.bruno@ gvillesun.com.
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