Red Tide Midweek Update for February 19, 2025

Current Conditions
Over the past week, the red tide organism Karenia brevis was detected in 34 samples collected from Florida. Bloom concentrations (>100,000 cells/liter) were observed in three samples: two from Sarasota County and one from Charlotte County. We continue to use chlorophyll satellite imagery (USF, NOAA NCCOS) to track this bloom and imagery varies from day to day. Based on satellite imagery from February 17, the clearly delineated offshore patches of elevated chlorophyll described for the past couple of weeks appear to have been spread northward along the coast by currents and lessened in intensity. A slightly elevated chlorophyll feature now extends from off of the mouth of Tampa Bay down to Lee County, and up to ~15 miles offshore. A smaller patch of elevated chlorophyll was also observed near the border of Collier and Monroe counties. 

Additional details are provided below.

• In Southwest Florida over the past week, K. brevis was observed at background to very low concentrations in Pinellas County, very low and low concentrations in Hillsborough County, background to low concentrations in Manatee County, background to high concentrations in Sarasota County, very low and medium concentrations in Charlotte county, background to very low concentrations in Lee County, background concentrations offshore of Collier County, and background to low concentrations offshore of Monroe County.
• In Northwest Florida over the past week, K. brevis was observed at background concentrations in one sample collected from Okaloosa County.
• Along the Florida East Coast over the past week, K. brevis was observed at background concentrations in one sample collected from Duval County.

Fish kills suspected to be related to red tide were reported to FWC’s Fish Kill Hotline and other partners over the past week for Southwest Florida (Manatee, Sarasota, Charlotte, Lee, Collier, and Monroe counties). 

Respiratory irritation suspected to be related to red tide was reported over the past week in Southwest Florida (Manatee, Sarasota, Charlotte, Lee, Collier, and Monroe counties). For forecasts that use FWC and partner data, please visit the National Oceanic and Atmospheric Administration’s Gulf of Mexico Harmful Algal Blooms Forecast.

Forecasts by the USF-FWC Collaboration for Prediction of Red Tides for Pinellas County to northern Monroe County predict variable movement of surface waters and net southeastern transport of subsurface waters in most areas over the next 3.5 days.

The next status report will be issued on Friday, February 21. Please check our daily sampling map, which can be accessed via the online status report on our Red Tide Current Status page. For more information on algal blooms and water quality, please visit Protecting Florida Together.

This information, including maps and reports with additional details, is also available on the FWRI Red Tide website. The website also provides links to additional information related to the topic of Florida red tide including satellite imagery, experimental red tide forecasts, shellfish harvesting areas, the FWC Fish Kill Hotline, the Florida Poison Information Center (to report human health effects related to exposure to red tide), and other wildlife related hotlines.

To learn more about various organisms that have been known to cause algal blooms in Florida waters, see the FWRI Red Tide Flickr page. Archived status maps can also be found on Flickr.       

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