Hypothermia, as in too much cold water, is the new killer:
In concluding the International Year of Biodiversity, the good news is that manatees are still with us, the bad news is that manatee deaths in U.S. waters continue to climb. In 2009, there were 429 reported manatee deaths, which was about double the number from 2008. As of December 2010, however, manatee deaths totaled 699.
Of the several factors that can cause manatee deaths, the most common one is human-caused: boat collisions. According to the Florida State Fish and Wildlife Service (FWS), 97 of 2010′s manatee deaths were due to boats or other water craft. That number seems consistent from year to year.
However, another death-factor has entered the survival game and is out-pacing boat strike deaths; a growing number of manatee deaths are the result of hypothermia – manatees experiencing “cold stress” resulting from entry into/contact with much colder waters. The FWS estimates that 244 of last year’s manatee deaths (nearly one third) were due to exposure to cold water.