A watchdog groups say Florida is on pace for another record year for manatee deaths.
So far, 166 manatees have died statewide through March 2. Cold spells are to blame for 51 deaths.
The Public Employees for Environmental Responsibility Executive Director Jeff Ruch says Florida manatees are one big freeze away from an ecological disaster.
Red tide and boating deaths are another concern as manatees seeking warm waters often get stuck in residential canals.
Florida's annual manatee counts have more than doubled in the past 20 years, to more than 6,600. The federal government reclassified them from endangered to threatened.
Florida Today reports that a researcher at Florida Atlantic University is working on alarm that could alert manatees of an approaching boat, possibly reducing deaths.
In 2017, 538 manatees died compared with 472 manatee deaths in 2016.