MIAMI (CBSMiami/CNN) - More than 1,000 manatees in Florida have died this year, a new report confirmed this week. It's the highest recorded number of manatee deaths in decades.
As of November 12, a recorded 1,003 manatees have died in the state throughout 2021, according to a mortality report from the Florida Fish and Wildlife Conservation Commission (FWC).
The primary driver of manatee deaths this year is starvation, the FWC said in a statement last week, ahead of the most recent report.
CNN has reached out to the FWC for comment and is waiting to hear back.
The atypically high number of manatee deaths prompted the FWC earlier this year to declare an unusual mortality event.
By this time last year, 498 manatees had died -- a number that's more than doubled in 2021.
In an interview earlier this month, Michael Walsh, a clinical associate professor of aquatic animal health at the University of Florida College of Veterinary Medicine, said that the surge in manatee deaths this year indicates deeper problems within their marine ecosystems.
In Brevard County, which has seen the highest number of manatee deaths this year at over 320, the Indian River Lagoon -- a popular warm-water refuge for manatees -- has lost an estimated 58% of its seagrasses over the last 11 years, according to the St. Johns River Water Management District, a regulatory agency that oversees the lagoon.
Seagrasses are an essential food source for Florida's "sea cows."
That seagrass breakdown is partly due to harmful algal blooms, which form when nutrients from wastewater, microplastics, or toxic chemicals leach into manatees' marine habitats.
Those blooms cover the surface of the water, preventing sunlight from reaching the seagrasses below.
"A lot of our environments are under pressure, and if we do not relieve that pressure, those systems will break," Walsh said
. "This is a continual warning sign that this is a gigantic ecosystem problem, not just a manatee problem."
Upon reaching this latest milestone, ZooTampa at Lowry Park, one of four manatee critical care centers in the US, called for manatees to be relisted as endangered species.
The US Fish and Wildlife Service downlisted manatees from endangered to threatened in 2017, citing "notable increases in manatee populations and improvements in its habitat."
But downlisting manatees hasn't eliminated the threats they face, which include insufficient food, habitat loss, pollution, and climate change, among others.
Changing their status back to endangered will "keep the needed focus on protecting this species," ZooTampa said in a statement shared with CNN.
"The loss of more than 1000 manatees this year is deeply concerning and will have serious repercussions for years to come," the Florida zoo said.
The FWC said it will continue with a "comprehensive investigation" and will "closely monitor the situation" as manatees move into their warm-water habitats for the winter.
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