TREASURE COAST - Manatees are dying at an unusually high rate so far in 2021, nearly tripling the normal numbers.
According to the Florida Fish and Wildlife Conservation Commission, 432 manatees have died in Florida between Jan. 1 and March 5.
In the same time period for the last five years, there were 163 deaths in 2020, 149 in 2019, 176 in 2018, 107 in 2017, and 137 in 2016. The five-year average for manatee deaths in this time period is 146.
In all of 2020, the FWC recorded 637 manatee deaths.
So far in 2021 the Treasure Coast has seen 15 manatee deaths in Indian River County, five deaths in St. Lucie County, and 26 deaths in Martin County. None of the Treasure Coast deaths so far this year have been watercraft-related.
Only 17 of the 432 deaths statewide were due to collisions with watercraft. An additional two deaths were caused by other human activity. Twenty-nine were perinatal deaths occurring in the period immediately after birth, 41 were found to be caused by cold stress, and 32 due to natural causes. Most of the rest were not necropsied, so there is no official cause of death determined.
The experts seem to think that the primary cause is a loss of food, particularly seagrass. Manatees are herbivores. According to Save the Manatee Club, manatees need to eat plants every day to maintain their average weight of 800-1,200 pounds.
“Environmental conditions in portions of the Indian River Lagoon remain a concern,” said a March 11 statement from the FWC. “Preliminary information indicates that a reduction in food availability is a contributing factor. We will continue with a comprehensive investigation and share information as it becomes available.”
“Many manatees in Florida have lost their lives this winter season to dwindling seagrass resources as well as cold weather,” Save the Manatee Club said in a March 3 statement. “Despite their large frame, manatees actually have relatively little body fat compared to other marine mammals and are quite susceptible to cold water temperatures.”
According to St. Johns River Water Management District Executive Director Dr. Ann Shortelle, “During the past decade, a series of algal blooms in the Indian River Lagoon has impacted water clarity, resulting in significant losses of seagrass throughout the 156-mile-long estuary. The decline didn’t happen overnight. The stunning water views, the fishing and recreational opportunities that drew people to the area have resulted in the water quality conditions we see today. Too many nutrients, specifically nitrogen and phosphorus, are entering the lagoon from over fertilized lawns, faulty sewage treatment, and leaching from septic tanks.”
The FWC expressed hope that the warmer weather will help the manatees find food.
“As water temperatures warm, manatees naturally disperse from their winter habitats, traveling to other areas of the state and beyond,” the FWC said. “This dispersal should lead manatees to better habitats.”
For more information about helping manatees, visit www.savethemanatee.org.
If you see a sick, injured, or dead manatee, call the FWC Wildlife Alert hotline, 1-888-404-FWCC, or #FWC on a cell phone.