Exposure to low temperatures is responsible for the deaths of 77 manatees including several newborns, since the beginning of the year, state wildlife biologists report.
This number of cold-stress manatee deaths exceeds the previous record of 56 in a single year, which was set in 2009.
The endangered mammals cannot tolerate water temperatures lower than 68 degrees F for long periods and gather at natural springs or warm-water outflows of power plants in the winter. But this January many manatees could not get to warm water in time.
Biologists with the Florida Fish and Wildlife Conservation Commission's Fish and Wildlife Research Institute have documented more than 100 dead manatees so far this year and they continue to recover and examine carcasses, so the total is expected to rise. But they expect the death rate to slow down as water temperatures warm.
This year, manatees swam to warm Florida waters in record numbers. During the state's annual week-long manatee survey that began January 11, biologists counted an all-time-high number of manatees - 5,067 manatees statewide.
A team of 21 observers from 10 organizations counted 2,779 manatees on Florida's east coast and 2,288 on the west coast. The final numbers will be published at the end of February, following data verification.
"This year's high count reflects the influence that weather has on aerial survey results," said biologist Holly Edwards with the Florida Fish and Wildlife Conservation Commission, FWC.
"The record-breaking cold temperatures helped to bring many more manatees to the warm-water sites than in previous years," said Edwards. "In addition, the calm, clear weather conditions on the days of the survey helped us to see and count record numbers."
Mother and calf manatees in the warm waters of Florida's Crystal River, January 14, 2010. (Photo by Daniel Johnson)
This year's count exceeded the previous high count from 2009 by more than 1,200 animals.
While this year's results do not mean the manatee population grew by more than 1,200 animals in a single year, they tell researchers there are at least 5,000 manatees in Florida waters.
The FWC is encouraged to have counted so many manatees. The high count is consistent with models that show the manatee population is growing or stable in most areas of the state.
"Counting this many manatees is wonderful news," said FWC Chairman Rodney Barreto. "The high count this year shows that our long-term conservation efforts are working."
"The high count is fantastic news and perhaps a once in a lifetime count due to the prolonged cold spell," said Patrick Rose, aquatic biologist and executive director of Save the Manatee Club. "Just as the manatee's need to stay warm has allowed us to better count them, we must ensure that these warm- water refuge sites remain available in Florida or the population could suffer in catastrophic proportions.
"We must work to keep the current protections in place and secure the population's future survival by continuing to protect both individual manatees and their habitat," said Rose.
But FWC Research Institute biologists also had some sobering news this month. They announced January 6 that the total number of manatee deaths for 2009, 419 animals, has surpassed the highest number on record for a calendar year.
FWC biologists in the field have been working overtime during the past three weeks to save the lives of manatees affected by the cold.
In St. Petersburg, for instance, FWC biologists rescued a juvenile manatee from a canal. Rescuers pulled the nearly seven-foot female manatee from the 53-degree water. Prolonged exposure to water of that temperature can lead to cold-stress syndrome and ultimately death in manatees. Biologists took the manatee to Tampa's Lowry Park Zoo.
In addition, FWC staff members and conservation partners are working extended hours to recover and transport carcasses to the FWC's Marine Mammal Pathobiology Laboratory in St. Petersburg. There, biologists perform necropsies, or animal autopsies, on each manatee to determine the cause of death and gather additional data. Carcasses that cannot be transported are examined in the field.
"Ironically," said Rose, "the very weather conditions that brought us such good news about the size of the manatee population, is set to have dramatic fatal consequences for dozens more individual manatees. I want to personally thank all those who are doing everything they can to find and rescue these manatees before they succumb to cold stress. This includes those boaters and citizens who report the sick manatees to the state and federal Fish and Wildlife agencies who work night and day, and the facilities and partners such as Epcot's Living Seas, Lowry Park Zoo, Miami Seaquarium, SeaWorld, and the University of Florida School of Veterinary Medicine."
"We are deeply concerned about these impacts on manatees and other fish and wildlife," said Chairman Barreto. "We appreciate all the time and effort being put into the process of documenting the effects of this unprecedented event and ask the public to assist in the effort by reporting dead or distressed manatees to the FWC Wildlife Alert Hotline at 888-404-FWCC (3922)."
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