Manatee winter deaths in Florida’s Brevard County plunge—which could portend trouble

The winter killing season for manatees along Central Florida’s Atlantic coast is winding down with an astounding turn of events—a tiny fraction of the animals died compared to during the last two years.

From January through March in Brevard County waters, authorities collected 275 dead manatees in 2021 and 281 last year. The toll was 12 through the middle of March this year.

It’s not clear how encouraging that plunge in mortalities is, or if it reflects the species having reached rock bottom in Brevard. None of the dozen dead was a baby or very young manatee and that is potentially a bad sign.

Brevard’s waters have seen a pollution-driven ecosystem collapse that has wiped out seagrass that manatees forage on. State veterinarian Martine de Wit said chronic starvation may leave manatees in debilitated condition and unable to reproduce.

“We can assume less manatees were born if we see less dead ones,” de Wit said.

Other authorities say seagrass rebounded slightly in the north end of Brevard’s Indian River Lagoon, in waters called Mosquito Lagoon, and that may have helped manatees withstand winter’s temperatures.

But another possibility may be that so many manatees died in Brevard County last year and in 2021, when a record-setting 1,101 perished statewide, that Brevard’s population of the animals has shrunken to the hardiest survivors.

“We are working on abundance estimates now and hopefully we will have numbers on that this fall,” said Ron Mezich of the Florida Fish and Wildlife Conservation Commission.

The largest share of manatee deaths in Florida so far this year has occurred in waters around Lee County in the southwest corner of the state, which has been plagued with toxic, bacterial red tides.

This year’s toll in Lee County has been 44 through March 10, with 15 of those from March 1 through March 10.

Wildlife authorities assume the reported number of deaths is less than the actual number, with some or many manatee carcasses in the wild never observed.

Along Florida’s Atlantic coast, this was the second winter that a partnership of state and federal wildlife agencies set up an experimental and emergency feeding station at the Florida Power & Light Co. generating plant along the Indian River south of Titusville.

Last winter, the agencies hand fed 202,000 pounds of mostly romaine lettuce to manatees that gathered at the plant because of its warm-water discharges during cold weather.

Almost twice that amount was given out this year, beginning in early December and costing nearly $250,000 in public and private contributions. The feeding program concluded March 17.

“Considering the large number of manatees that were lost, there is going to be an impact on the population that has yet to be defined,” de Wit said. “We expect to see long-lasting health effects from such a significant impact of malnutrition.”