"For the first time since records began being kept in Florida in the 1970s, the number of manatee deaths in a single year has topped 800, with two weeks remaining to the end of 2013."
"Numbers released by the Florida Fish and Wildlife Research Institute in St. Petersburg this week showed the number of dead manatees at 803 as of Dec. 13. That's about 16 percent of the state's estimated population of 5,000 manatees. ...
This year's record die-off was driven by two causes — one of which remains a mystery.
First a massive bloom of Red Tide algae along the state's southwestern coast caused 276 deaths early in the year. Red Tide has been around for centuries and has killed manatees before. But this year was the worst Red Tide die-off ever recorded.
Meanwhile, a mysterious ailment has been killing manatees in the Indian River Lagoon on the state's east coast. That's been going on since last year but hit a fever pitch in the spring. Twenty-five died in March."