FWC issues first midweek red tide update since end of May 2023, citing ‘bloom concentrations’ in 21 samples taken over past seven days

Five of those samples collected in Sarasota County

This Oct. 30 graphic shows red tide conditions off the Southwest Florida coast. Image courtesy FWC

As the executive director of the Sarasota Bay Estuary Program (SBEP) had warned in late the latter half of October, it appears that red tide is proving to be a problem along the Southwest Florida coast, including Sarasota County’s shoreline.

On Oct. 30, the Florida Fish and Wildlife Conservation Commission (FWC) issued a midweek red tide report, the first time it had done so since May 31, 2023, according to records that The Sarasota News Leader maintains.

In that Oct. 30 update, FWC wrote, “Over the past week, the red tide organism Karenia brevis was detected in 85 samples collected from Florida’s Gulf Coast. Bloom concentrations (>100,000 cells/liter) were present in 21 samples …” Five of those were collected in and offshore of Sarasota County. The others were as follows, FWC pointed out: “1 offshore of Pinellas County, 2 offshore of Manatee County … 4 offshore of Charlotte County, 8 offshore of Lee County, and 1 offshore of Collier County.”

Further, FWC noted that in Southwest Florida “over the past week, K. brevis was observed at … background to high concentrations in and offshore of Sarasota County,” as well as at background to medium concentrations in and offshore of Pinellas County, background to low concentrations in and offshore of Hillsborough County, very low to medium concentrations in and offshore of Manatee County, medium to high concentrations offshore of Charlotte County, very low to medium concentrations in and offshore of Lee County, and background to medium concentrations offshore of Collier County.

Moreover, the agency said that 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” — in Sarasota, Pinellas, Charlotte and Lee counties.

Additionally, FWC wrote in the Oct. 30 update, respiratory irritation “suspected to be related to red tide was reported over the past week” in Sarasota, Pinellas, Charlotte, and Lee counties.

Forecasts issued “by the USF-FWC Collaboration for Prediction of Red Tides for Pinellas County to northern Monroe County predict net western movement of surface waters and southeastern transport of subsurface waters in most areas over the next 3.5 days,” the Oct. 30 update added.

“We continue to use satellite imagery [provided by the University of South Florida (USF) and the National Oceanic and Atmospheric Administration (NOAA) through its National Centers for Coastal Ocean Science (NCCOS)] “to help track nearshore and offshore conditions,” FWC wrote.

This is the NOAA Harmful Algal Blooms satellite image for Oct. 30, using the same color coding system as the FWC graphic above.

For forecasts that use FWC and partner data, the agency continued, persons may visit the National Oceanic and Atmospheric Administration’s Gulf of Mexico Harmful Algal Blooms Forecast.

Anyone planning to go to the beach can use Mote Marine Laboratory’s Beach Conditions reporting system to check the conditions. However, some of Sarasota County-owned and operated beaches do remain closed because of the effects of Hurricanes Helene and Milton. A red bar at the top of a report for a specific beach notes such a closure.

This is part of the Oct. 31 report for conditions at Nokomis Beach. Image courtesy Mote Marine Laboratory
This is part of the Oct. 30 report for conditions at Siesta Beach. Image courtesy Mote Marine Laboratory

In an Oct. 22 update on the Sarasota Bay Estuary Program website, Executive Director David Tomasko reminded readers, “[W]e had previously noted the potential for a fairly massive red tide to impact us, while noting that the University of South Florida’s (USF’s) red tide forecasting model suggested that it might stay offshore, due to fairly persistent winds out of the east and northeast — Director’s Note: Red tide on the horizon?

“Well,” he continued, “the last few days have provided evidence that the USF model was likely accurate.”

A comparison of satellite imagery from Oct. 18, 20 and 21 showed evidence of red tide, he noted, adding that FWC “samples have verified it is red tide …”

At that point, Tomasko wrote, the red tide bloom was not strengthening.

Between Hurricanes Helene in late September and Milton in early October, an untold amount of stormwater runoff — with pollutants — has flowed into Southwest Florida waterways. Moreover, hundreds of thousands of gallons of sewage spills resulting from the rainfall associated with the storms have been reported by local government utility system operators. Sewage spills, especially, carry nutrients that feed the red tide algae, researchers have pointed out, with nitrogen having been identified as the primary food that spurs red tide blooms.

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