JACKSONVILLE, Fla. – Manatees are having a difficult time in Florida. So far, 819 manatee fatalities have been recorded by the Florida Fish and Wildlife Conservation Commission through June 25. For perspective, that is 182 more manatee deaths than the total recorded in 2020.
Some of the areas of concern along the Atlantic Coast include the Indian River Lagoon, where more than 300 manatees have died. These have been attributed to food loss and smelly algal blooms. Seagrass loss in this area is devastating. An area I used to frequent as a kid is now a disgusting wasteland of funky colored water, which appears nearly lifeless. Sixteen manatees have died in Duval County alone.
Manatees depend on seagrass and other aquatic vegetation for their diet, but sadly they are finding fewer areas for foraging. That’s due in part to man-made pollution from nutrient heavy wastewater and discharge that spike blooms of harmful algae. These nutrients combined with warmer water temperatures trigger abundant algae growth, which suffocates the underwater vegetation growth.
The shallow coastal areas where seagrasses occur are limited by water clarity because most species require high levels of light. Algae mats block sunshine and the grass beds die.
Evidence points to a recent phosphate dump into Tampa Bay from the Piney Point Reservoir making the problem even worse. The average estuary depth of just 12 feet sustains thousands of seagrass bed acres, drawing hundreds of manatees to the area.
The FWC is working with the federal government to investigate why so many manatees are dying. The state agency has declared this an “Unusual Mortality Event.” This means it’s unexpected and involves a significant die-off of a marine mammal population and requires an immediate response.
“There have been an extremely high number of deaths this winter and certainly the number one concern is lack of food out there,” said Craig Miller, curator of mammals at the Jacksonville Zoo & Gardens.
Miller, who oversees the zoo’s manatee critical care center, one of four such centers in the state, is talking about the lack of seagrass. Initial assessments indicate the high number of emaciated manatees is likely due to a decline in food availability.
According to the FWC, 42 percent of the manatee deaths so far this year took place near the Indian River in Brevard County. Biologists say this area has suffered a significant loss of seagrass beds for the past decade.
Also taking a toll on the population is boat strikes. As boaters, we can help these lumbering giants by following the posted speed zones. Avoid seagrass beds and other feeding areas. If you see a sick, injured or dead manatee, call the FWC at 1-888-404-3922.