The 22 dead dolphins that have washed up on southwest Florida beaches since Nov. 21 may have been killed by a chemical from the red tide that is wreaking havoc along the coast.
Blair Mase, a marine mammal stranding coordinator for the National Oceanic and Atmospheric Administration, told the Naples Daily News that tests aren’t complete yet but that it appears the dolphins were killed by brevetoxin from the red tide.
Florida Fish and Wildlife Conservation Commission officials were collecting water samples from beaches to test while collecting the bodies of the dead dolphins and other marine life that were killed recently across Lee and Collier counties.
The red tide has killed a number of sea turtles, fish, birds, and dolphins.
“What’s concerning is the red tide also affects dolphin prey,” Mase said. “Dolphins can die from either inhalation of the toxin or eating prey that have been exposed to the red tide.”
But Naples Harbor Master Capt. Roger Jacobsen said that the red tide didn’t appear to be a factor in Naples, where at least three of the dolphins have washed ashore since Sunday in Naples, including one that washed up on Monday morning at Moorings Beach.
“There is a natural flow of the Gulf of Mexico from north to south so the assumption at this point is they were floating down and just happened to wash up on our beach because we’re not really dealing with red tide in the city of Naples right now,” he told NBC 2.
Donna Collini, a resident of Toronto who spends her winters in Naples, said dead dolphins washed up on Sunday and Monday.
“It smelled like crazy and was laying there with its mouth open,” Collini told the Daily News. “People couldn’t believe what they saw, and everybody was taking pictures of it.”
Red tides typically last from October or November through January or February. The current red tide started in November 2017.
“Southwest Florida has been experiencing an ongoing severe bloom of a red tide organism since November 2017. The dinoflagellate (Karenia brevis) that forms red tide is commonly found at low levels in Gulf waters, but it can have devastating impacts when the cells multiply and form a harmful algal bloom. Other species, such as fish, sea turtles, and manatees are also confirmed to be dying as a result of this ongoing harmful algal bloom,” the National Oceanic and Atmospheric Administration stated.
Since July, 109 dolphins have died and washed ashore in southwest Florida, the agency said, calling it an unusual mortality event.
A similar mass stranding took place in 2005 and 2006, caused by exposure to red tide toxins, that left around 190 dolphins dead. This year, the numbers spiked in November after a calm October.
