Underwatertimes.com News Service - March 24, 2010 20:46 EST

As of March 19, biologists with the Florida Fish and Wildlife Conservation Commission's (FWC) Fish and Wildlife Research Institute (FWRI) have documented 431 manatee carcasses in state waters so far in 2010. This preliminary data indicates that in just three months, the number of manatee deaths has exceeded the highest number on record for an entire calendar year, which was 429 in 2009. The cause of death for the majority of these animals is cold stress.

The "cold-stress" category accounts for 222 documented manatee carcasses; however, it is likely the cold temperatures also contributed to many of the 108 deaths in the "undetermined" category and the 64 deaths in the "unrecovered" category.

Manatee deaths are categorized as "undetermined" when biologists are not able to confirm the cause of death, often because the carcasses are too badly decomposed. The "unrecovered" category includes carcasses that are unavailable to scientists, such as when carcasses are found in remote locations.

Unfortunately, the number of recovered carcasses for this year continues to be well above long-term averages. As the rate of cold-related deaths diminishes, FWC staff will begin to focus on determining the long-term implications for the manatee population, a process that could take several years.

The period of prolonged cold weather earlier this year exposed manatees in Florida to colder than normal water temperatures. Exposure to low temperatures over a period of time can cause a condition called "manatee cold-stress syndrome," which can result in death.

"The unprecedented rate of mortality this year is of great concern," said Gil McRae, FWRI director. "FWC staff, partners and volunteers have done a tremendous job working around the clock for weeks recovering carcasses and conducting rescues throughout Florida."

Since the cold weather conditions began to affect Florida, FWC staff and conservation partners have rescued 48 manatees from across the state and continue to respond to reports of distressed manatees.