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Manatees on Pace to Break Record for Number of Deaths in One Year

David Hinkle USFWS

According to the U.S. Fish and Wildlife Conservation Commission, 539 Manatees have washed up dead since January 1 of this year. It's a pace that could set a grim record, according to experts. In all of last year, 637 manatees died. At Manatee Park in Fort Myers, six have had to be rescued, which, according to Lindsay Bell at the gift shop, is not normal.

This time of year, there are more people than manatees at the park. More of Florida's chubby marine mammals graze along this stretch of water in December, January, and February, when gulf waters are more chilly. They seek refuge in the warm water coming off a nearby power plant.

“Manatees do not do well in waters below 68 degrees Fahrenheit because they can develop 'cold stress syndrome,' which can make them more vulnerable to disease, lesions, and emaciation,” says Jaclyn Lopez, the Florida director of the Center for Biological Diversity. She says manatees swim away in order to eat seagrass, which is their main source of food. But lately they haven't been finding as much of it, so they starve themselves while swimming back to warm waters. Lopez says they’d rather starve themselves than freeze.

In 2020, the state of Florida recorded a total of 637 manatee deaths, and in 2019, 607.

According to the preliminary manatee mortality report on FWC’s website, cold stress has accounted for 27 of the 539 deaths so far this year, which we are only three months into. In 2020, there were 52 cold stress deaths for the entire year.

While cold weather and insufficient amounts of sea grass contribute to the problem, a decline in sea grass can also be the result of chemicals like phosphorus and nitrogen, which contribute to algae blooms. Those blooms can become so thick that they block out sunlight, which kills the seagrass manatees eat. And then there's the issue Round-up runoff killing that same food source: A study released just this week shows glyphosate in the system of more than half of the manatees sampled, and while it's not clear whether that’s contributed to this unusual mortality event, what is likely is that glyphosate- commonly sold as Round-Up- is an herbicide capable of killing seagrass compounding the problem for animals already struggling to find enough to eat.

“Florida could better enforce compliance with the Clean Water Act in order to control the non-point source runoff nutrient pollution that fuels harmful algal blooms,” Lopez said. “Red tide is fed by these blooms and manatees are very susceptible to red tide.”

Captain Daniel Andrews is the founder and executive director of Captains for Clean Water; a grassroots nonprofit organization fighting to restore and protect water resources. They rose to prominence during the Red Tide crisis in 2018 and remain vocal advocates with a mission to educate the community while ensuring policymakers execute scientific solutions to water quality issues.

As a kid, Andrews fished the St.Lucie River, only to return years later to an estuary covered in green slime. He’s also seen vast areas of seagrass meadows fade away into bare mud flats.

“People need to educate themselves on the issues because there is a lot of misinformation spread by special interests who benefit from the status quo,” Andrews said. “These water issues affect our economy, our health, and our quality of life.”

Dr. Mike Parsons teaches Marine Science at Florida Gulf Coast University. He’s also the director of FGCU’s Coastal Watershed Institute (CWI) and the Vester Marine & Environmental Science Research Field Station. He said boater awareness and steps to improve water quality are necessary.

“Less fertilizer, putting pressure on elected officials in order to support measures to improve water quality, and protecting springs,” Parsons said. “Manatee populations have increased, and as their numbers continue to grow there will be more instances of human contact, including boat collisions.”

According to this year's data from the US Fish and Wildlife Commission, only 167 of the 539 deceased manatees have been necropsied so far to determine cause of death. Of those 27 died from cold stress, 20 were killed by watercraft, 66 were found to have died from "natural causes." and 29 were perinatal (meaning less than 5 feet in length, or babies).

 Manatee Park welcome center in Fort Myers, FL
Julie Glenn / WGCU
Manatee Park welcome center in Fort Myers, FL

Copyright 2021 WGCU

Michelle Alvarez