The largest die-off of manatees in recorded history has taken place in Florida as a result of the state's prolonged, record-low temperatures this winter.

A total of 368 manatees have died in Florida waters so far this year, according to the Florida Fish and Wildlife Conservation Commission (FWC). The unprecedented number of deaths in less than three months is just 61 shy of the number of manatees that died in all of 2009, 429, which itself was a record, said Katie Tripp, Save the Manatee Club's director of science and conservation.

FWC records show that 193 manatees died from cold stress from Jan. 1 through March 5. Another 151 deaths have been classified as undetermined, but the majority of these likely were caused by cold stress, officials said. The total manatee population in the state is about 3,800.

"Although air temperatures are starting to increase, it will take some time for water temperatures to rise," Tripp said. "A number of manatees are still in need of rescue for cold stress, but all three critical care facilities are at or near capacity."

Many manatees succumbed quickly to cold water temperatures, but several dozen were rescued and taken to three facilities in Florida that are authorized to provide critical care for sick and injured manatees.

The U.S. Fish & Wildlife Service and Homosassa Springs Wildlife State Park on Florida's west coast has provided housing for manatees in the park's above-ground pool. Manatees are being transferred from critical care facilities to Homosassa Springs to create more space for additional cold-related and other rescued manatees at the critical care facilities. Save the Manatee Club is providing the funding to heat the pool and ensure veterinary care for the transferred manatees for up to two months.

"The high number of manatees who died and are still dying from the effects of Florida's prolonged cold weather underscores how imperative it is to protect winter warm-water habitat," said Patrick Rose, an aquatic biologist and executive director of Save the Manatee. "Further, as we head into Florida's legislative session, continued funding for the state's manatee critical care program is at grave risk of being cut to make up for state revenue shortfalls. I hope this disastrous winter will serve as a strong reminder to state legislators that Florida's critical care program for manatees is absolutely vital to the survival of the species, and that the funding for this crucial program must be maintained."

Boaters also play an important role in protecting manatees this spring, Tripp said.

"As temperatures rise and the weather gets better, people are going to be heading back out in the water in their boats," Tripp said. "People really need to be more vigilant. These manatees are going to be very hungry and vulnerable after the events of this winter, so extra vigilance will be imperative from the boating community to watch out for manatees and report any manatees that appear unhealthy or injured to the (FWC)."

Distressed manatees can be reported to the FWC at 888-404-3922.

tohara@keysnews.com