Manatee mortality in Florida has shot up this year, with 358 recorded deaths in January and February. Last year, the first two months had a combined total of 143 deaths — less than half this year’s current toll. Conservationists worry that the manatees are starving to death.
Some causes of 2021 manatee deaths are known and include boat strikes, cold stress and natural deaths. But many have died for unknown reasons. Pat Rose, director of Save the Manatee Club, suspects one of these reasons is a sea grass shortage. “It’s something we’ve never really seen before,” Rose said. “It looks like we have a substantial number of manatees that are starving.”
The potato-shaped marine mammals spend up to seven hours a day eating freshwater plants like hyacinth, water lettuce, pickerelweed and hydrilla, and saltwater foods like sea clover, marine algae and grasses. They eat 100 to 200 pounds of grass per day, which is about 10-15% of their body weight. With an estimated 6,300 manatees in Florida, that’s a lot of grass.
Sea grasses have other crucial benefits to life on the planet, such as storing carbon and thus staving off climate change. But warming waters, rampant coastal development, agricultural runoff and pollution from wastewater treatment plants are all causing toxic algae blooms which spell the doom of grasses.
Nearly half of this year’s manatee deaths have been in Brevard County, home of a crucial manatee habitat called Indian River Lagoon. “The raw truth of the matter is due to negligence of our stormwater we’ve had continual algal blooms over the past 10 years, which blocks out sea grass and kills it,” Billy Rotne, an Indian River Lagoon guide, told the News-Press.
The Florida Fish and Wildlife Conservation Commission is the agency that performs necropsies, which are autopsies on non-human animals. But between the high death rate of manatees this year and difficulties of working during the pandemic, the commission is behind on its caseload.
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