Recent sampling from the Florida Fish and Wildlife Conservation Commission has detected medium to high concentrations of Karenia brevis, the dinoflagellate that forms red tide, offshore of Sanibel.

Elevated K. brevis concentrations were collected from sampling points south and southwest of the island, with the closest sample being 5.5 miles south of Bowman’s Beach. Satellite imagery from NOAA’s National Center for Coastal Ocean Science has also pointed to the presence of an algal bloom offshore of Sanibel, with K. brevis predicted as the predominant species.  

The Lee County Department of Health has issued a health alert about the potential dangers associated with red tide, and urges the public to exercise caution around the area. Additional updates from the county can be found here.

“The proximity to Sanibel is concerning as the U.S. Army Corps of Engineers began Recovery Operations, making releases from Lake Okeechobee, on Dec. 7,” said Policy Associate Allie Pecenka. “However, the operations have not increased the amount of water entering the estuary much more than it was already receiving without lake releases, raising from 2,000 cubic feet per second (cfs) to 2,100 cfs.”

“While we know that large, damaging releases from the lake can exacerbate red tide blooms by feeding them with nutrient-rich waters, the low volume of the present releases and location of the bloom offshore do not lead local experts to suspect that recovery operations will exacerbate the current bloom,” she added.

Currently, 14-day average flows to the Caloosahatchee and Estuary remain in the optimum flow envelope for estuary health and maintenance of the ecosystem’s salinity gradient throughout the dry season.

SCCF will remain engaged with water managers to ensure they are aware of any changing conditions and can react accordingly to protect our estuary and the surrounding communities.

“Consistent, daily monitoring of how this bloom evolves combined with the communication of this data to water managers will be the most effective mode of defense against the intensification of red tide in our community,” Pecenka said.

The Army Corps stated that the current lake discharges can be altered based on changing conditions in the estuaries, such as red tide blooms, and has committed to a flexible, feedback-driven approach to their release schedule. SCCF provided comments to the Corps on Dec. 10, updating water managers on the status of K. brevis in local waters while emphasizing the need for a science-driven, reactive approach to recovery operations.

With the health of our ecosystems and economy in mind, SCCF’s Marine Laboratory and Environmental Policy team will continue to closely monitor this dynamic situation while sharing recommendations with decision-makers and our local community.

Have You Noticed Red Tide?

To date, SCCF has not been informed of any acute red tide impacts to humans or wildlife such as fish kills or respiratory irritation. These impacts would indicate the intensification of red tide at the local level and provide valuable data to communicate with water managers.

If you observe red tide wildlife impacts or experience health symptoms while on Sanibel, please share it with us at apecenka@sccf.org.