State wildlife officials say a preliminary total of 829 manatee deaths were documented in Florida waters during 2013.
The Florida Fish and Wildlife Conservation Commission announced this week that it's had to step up efforts to respond to distressed manatees.
Marine mammal staff and law enforcement responded to manatees suffering from the effects of red tide in southwest Florida from January through May. Florida red tide releases a toxin that affects manatees' nervous systems. It reportedly caused the deaths of a record 276 manatees.
On Florida's east coast, researchers continue to investigate the cause of death of more than 100 manatees.
Last year's record total nearly matched the death toll from the previous two years, which were 453 and then 392. A total of 766 deaths were recorded in 2010.