Florida wildlife officials are investigating a higher than normal number of manatee deaths in Everglades National Park over the last two months, after a rare Bryde’s whale beached itself in January.
Altogether nine dead manatees have been reported in park waters, but only four bodies were recovered. Two deaths were blamed on cold weather and biologists are still trying to determine how the other two died. The manatees were found in isolated areas accessible only by boat, including Mud Bay, south of the Turner River, and Rodgers River Bay. The remote location has complicated efforts to determine what killed them, Michelle Kerr, spokeswoman for the Fish and Wildlife Research Institute, said in an email.
“Stranding response to remote areas such as [Everglades National Park] is challenging due to [the] delay in reporting and accessibility to verify and necropsy,” she said.
The deaths come after a brutal year for manatees, when a toxic red tide swept up and down the lower Gulf Coast. The tide was the largest and longest in a decade and left beaches and canals clogged with dead sea life, including manatees, dolphins, turtles and fish. The blooms were blamed for killing 144 manatees and suspected of killing another 71 last year, more than three times the number in 2017.
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The tide has subsided in recent months, with much of the coast declared bloom-free. Last week, low to medium levels were only detected south and west of Everglades City.
Late last month, a rare Bryde’s whale was found beached about 10 miles south of Flamingo. National Oceanic and Atmospheric Administration Fisheries biologists are still trying to determine the cause and whether the whale belongs to a tiny population that inhabits the Gulf of Mexico. Only 100 are believed to live in the Gulf and are now being considered for the Endangered Species List. If added as distinct subspecies, it would become one of the rarest whales in the world, NOAA officials say.
When they examined the 38-foot whale, biologists found it underweight with a matchbook-size piece of plastic in its stomach.
The carcass was buried at Fort DeSoto County Park south of St. Petersburg. Later this year, the Smithsonian plans on retrieving its skeleton to use for future research, said NOAA spokeswoman Kim Amendola.
The number of manatees found in less than two months is higher than average but not considered unusual, Kerr said. More than seven in 72 hours would be considered high enough to be classified as a mortality event meriting closer scrutiny. It’s also difficult to track dead manatees in the park. In such isolated areas, they are often spotted by plane, she said, and if they are necropsied their bodies are often left behind. To avoid counting animals twice, biologists rely on comparing photographs, she said.