SCCF: Some red tide impacts showing up on islands
On Jan. 14, the Sanibel-Captiva Conservation Foundation (SCCF) reported that local concentrations of Karenia brevis — the organism that causes red tide — had begun trending upward in Southwest Florida over the past week, along with impacts to coastal wildlife on Sanibel and Captiva.
At the time, data from the Florida Fish and Wildlife Conservation Commission detected K. brevis at background, very low and low concentrations in Lee County, with medium concentrations recorded offshore of Sanibel and at the Alison Hagerup Beach Park on Captiva.
Multiple instances of wildlife impacts had been reported on the islands, potentially linked to the presence of K. brevis. They included strandings of various fish species, including mullet and catfish, crabs and eels, along with two black scoters found deceased on the shore.
“While determining the cause of death for wildlife is difficult to prove without individual examination, the close proximity of K. brevis provides reason to believe these impacts are correlated to the existing red tide bloom,” SCCF Policy Associate Allie Pecenka.
K. brevis cells release a toxin that attacks the nervous system of animals. The neurotoxins, called brevetoxins, are often fatal to fish, birds, sea turtles and marine mammals and can have adverse impacts in humans. Even when K. brevis cell counts read as “not present” or “background concentrations,” animals may still experience brevetoxicosis — red tide poisoning — symptoms due to foraging offshore where a bloom is active. Toxins can also bioaccumulate in prey and plants that are eaten by larger animals, such as cormorants and sea turtles.
As of Jan. 14, satellite imagery suggested that the bloom contained a patch located southwest of Sanibel and offshore of Naples.
“Impacts of the red tide bloom will likely be seen during south and westerly winds because of the onshore transport of the bloom patches,” SCCF Marine Lab Director Dr. Eric Milbrandt said. “While there is an uptick in strandings this past week, the largest detectable patch from satellite imagery is 15-20 miles offshore and south of Sanibel.”
He added that the distribution of the bloom can change daily due to wind and currents.
If you notice deceased wildlife or fish kills or experience respiratory impacts potentially linked to red tide, email sccf@sccf.org with details including the location, date and photos of wildlife impacts.
Report wildlife behaving erratically — unable to stand or fly, displaying tremors, apparent weakness or confusion — to the Clinic for the Rehabilitation of Wildlife (CROW) at 239-472-3644, ext. 222.
The National Centers for Coastal Ocean Science reported that water samples from Jan. 6-13 detected K. brevis along the coast at levels that pose a respiratory irritation risk in Charlotte, Lee, Manatee, Monroe, Pinellas and Sarasota counties.
The SCCF reported that it will continue to monitor the situation closely, while using its local water quality reports to advocate for strategies to best support coastal ecosystems and communities.