* Offline power plant keeps water warm just for manatees
* Hundreds of manatees huddle in the warm water
* Record number of manatees died last year
By Carlos Barria
RIVIERA BEACH, Fla., Jan 7 (Reuters) - An offline Florida power plant is providing a warm-water refuge for several hundred manatees who like the Sunshine State's human residents are shivering in record low cold temperatures.
Close to 400 of the bulky, wrinkly and endangered sea mammals, including mothers and young, have congregated at an outlet on Florida's Intracoastal Waterway where heated water flows from the Riviera Power Plant operated by the Florida Power and Light Company, a unit of the FPL Group Inc (FPL.N).
The oil- and gas-fired plant was taken off line last year for modernization but FPL has installed a special heating system to keep waters at an attractively balmy temperature for the manatees who have been gathering at the outlet for years.
"The water that discharges into the area where the manatees gather comes out at 92 degrees Fahrenheit (33 Celsius). It gives a nice combination by the time it mixes with the natural water ... it's very comfortable for them and they enjoy it," FPL spokesperson Sharon Bennett told Reuters.
Viewed from the dock, dozens of manatees, their gray bodies huddled close together, lolled in the warm greenish waters around the power plant outlet. Some lifted their bewhiskered faces out of the water to gaze back at onlookers.
Many of the manatees had scars on their bodies caused by boat hulls and propellers.
Florida's wildlife and human inhabitants are currently shivering in frigid temperatures that are even threatening the state's multibillion-dollar citrus crop. Though hardly on par with frozen northern states such as North Dakota, where Thursday's high was expected to be minus 11 F (minus 24 C) in Bismarck, temperatures in the 30s and 40s are rare in subtropical south Florida.
The West Indian manatee, related to the African and Amazon species and to the dugong of Australia, grows to 10 feet (3 metres) and more than 1,000 pounds (450 kg).
Although they have no natural enemies, manatees are routinely crushed or drowned in canal locks, run over by speeding boats or hurt by fishing line and hooks. They are also vulnerable to cold water in winter and to deadly blooms of "red tide" algae.
Bennett said FPL was working with local fish and wildlife authorities to maintain the warm water refuge for the manatees while the power plant was being upgraded into a more modern and efficient unit, a process that could take several years.
"It's less expensive for us to operate it this way during this down-time than to run the generators to heat the water," she said, calling the special heating system FPL's contribution to the preservation of the environment and its wildlife.
Bennett said the company hoped to eventually install a public viewing area at the plant to allow visitors to see the gathering of the sea mammals.
Although state scientists counted a record high number of 3,807 manatees in Florida waters last year, topping the previous high in 2001 by more than 500, local wildlife officials say 429 manatees died in Florida last year.
This was a record number of deaths for one year, higher than 2006, when 417 deaths were documented in Florida.
Of the 2009 deaths, 56 were caused by cold stress.
A lower-than-average total of 337 manatee deaths was reported in 2008.
Additional reporting and writing by Pascal Fletcher; Editing by Jane Sutton and Sandra Maler