A red tide bloom that's lingered off Southwest Florida for a few weeks has made its way into local bays and is killing larger marine life, such as sea turtles.
Karenia brevis, the red tide organism, produces brevetoxins that can affect the central nervous system of fish and other vertebrates, killing them, according to Mote Marine Laboratory and Aquarium. Red tide counts have ranged from normal background levels to 1 million or more cells per liter. Fish kills and breathing irritation can start when levels reach 10,000 cells per liter, according to the Florida Fish and Wildlife Conservation Commission.
"This is not a happy day," said Eve Haverfield, director of the nonprofit Turtle Time. "I had four dead ones this morning, and I had four dead yesterday. Eight in two days is pretty drastic."
Three of the eight were struck by boats, although it is unknown if the sea turtles were alive or dead when they were hit.
Over 40 fish kills associated with red tide blooms have been reported since the end of September in Collier and Lee counties with the majority found around Naples, Sanibel and Marco Island waters, according to FWC.
Water quality scientists from the Sanibel-Captiva Conservation Foundation said the bloom has moved into San Carlos Bay but that conditions are not nearly as bad as 2018, when millions of pounds of dead sea life were removed from local beaches.
"Last year we had this giant patch of red tide that was 20 or 30 miles and there was high concentrations," said Rick Bartleson, a chemist at SCCF. "This isn't, so far, anything like last year, so you don't need to worry about it being like [that].”
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