Wednesday, January 5, 2011

2010 Was A Cold Year For Manatees

There were two periods of unusually cold weather in 2010 that contributed to a larger than normal number of manatee deaths. This year there were more than double the yearly average of manatee deaths compared to the past five years. Biologists with the Florida Fish and Wildlife Conservation Commission's (FWC) Fish and Wildlife Research Institute (FWRI) documented 767 manatee carcasses in state waters in 2010, 185 of those occurring in Brevard County (the most out of any county in the state). The cold weather in Florida caused many of the deaths which the category of "cold-stress" being used for 279 of the documented cases (90 in Brevard County). Of these cases, 244 occurred in the early part of the year and 35 occurred in December. Cold-stress also contributed to the deaths of 21 of the 96 manatees in the "newborn" or "perinatal" category and most likely contributed to many of the 214 deaths in the "undetermined" category and the 68 deaths in the "unrecovered" category. Brevard County is generally in the number one or two spot for number of manatees deaths throughout the year compared to other Florida counties.
FWRI Director Gil McRae said, "The unusually high number of manatee deaths in 2010, including those caused by the two periods of cold weather, are of concern to the FWC. Over the next few years, the FWC will be relying heavily on monitoring programs to better understand any long-term implications for the manatee population. In the meantime, we will continue to work with our partners to enchance the availability of natural warm-water sites and to rescue manatees in distress."
The reasons for cold stress associated deaths are not completely clear but there have been studies done to determine the causes. When manatees are exposed to cold water (at or below 68 degrees Fahrenheit) their metabolism slows, leading to digestion problems, decreased appetite, and weight loss. These conditions weaken the manatee's immune system making them vulnerable to environmental toxins as well as a variety of diseases, including pneumonia. When cold weather comes, manatees generally migrate to relatively warm freshwater springs or far enough south to avoid colder water. But over the years more and more manatees have started accumulating near warm water discharges from industrial plants (such as power plants). As outdated power plants are shut down, these warm water oases are removed and some manatees are not able to find substitutes in time.
To learn more about manatee conservation, go to To view the 2010 preliminary mortality numbers as well as a Web article detailing the cold-related manatee die-off in early 2010, visit and click on "Manatee Mortality Statistics".
To report a dead or distressed manatee, call the FWC's Wildlife Alert Hotline at 888-404-FWCC (3922).