No red tide detected in or offshore of Sarasota County in FWC sampling last week
On Oct. 16, David Tomasko, director of the Sarasota Bay Estuary Program (SBEP), warned that “a very large bloom” of the red tide algae, Karenia brevis, was offshore of the Sarasota County coast.
That bloom, he wrote, appeared to encompass an area in “excess of 1,000 square miles, mostly centered off the mouth of Tampa Bay, but extending from north of Tarpon Springs down to Big Pass and New Pass.”
He provided satellite images captured by the European Organisation for the Exploration of Meteorological Satellites, which were processed by NOAA’s National Centers for Coastal Ocean Science [NCOOS] — https://coastalscience.noaa.gov/science-areas/habs/hab-forecasts/gulf-of-mexico/florida-satellite-imagery/
Tomasko did note that the “University of South Florida’s Ocean Circulation Model — which is used to predict red tide movements — expects that the red tide will mostly stay offshore, in response to winds out of the East to Northeast.”
On Oct. 18, two days after Tomasko provided those comments on the SBEP website, the Florida Fish and Wildlife Conservation Commission (FWC) released its latest update on red tide conditions in Florida, the first such report since Oct. 4. FWC said that red tide “was detected at background to very low concentrations in 5 samples from Southwest Florida. Bloom concentrations (>100,000 cells per liter) were not observed over the past week.”
“K. brevis was observed at background concentrations in Pinellas County and background to very low concentrations in Manatee County,” last week, FWC added.
Nonetheless, like Tomasko, FWC noted, “The most recent satellite imagery indicated at least two distinct patches of elevated chlorophyll offshore of southwest Florida, one extending northward from northern Pinellas County, and a second patch extending southward from southern Pinellas County to Charlotte County ….”
FWC then pointed out, “Patches are shifting daily as a result of winds and ocean currents, and we are working closely with partners at USF [the University of South Florida] and NOAA NCCOS to monitor these critical data streams. While it is suspected that these patches could contain red tide, without samples, we cannot confirm whether they are dominated by red tide or other algae. It should be noted that red tide was observed offshore and onshore prior to the passages of both [Hurricanes] Helene and Milton. Sampling is ongoing, with FWC conducting sampling offshore of Pinellas County [on Oct. 18], and collaborative offshore sampling trips are planned for next week.”
FWC added on Oct 18, with emphasis, “No reports of fish kills suspected to be related to red tide were received from FWC’s Fish Kill Hotline or other partners over the past week,” nor was respiratory Irritation suspected to be related to red tide reported over the past week.
The next full status report will be issued on Friday, Oct. 25, FWC pointed out. In the meantime, FWC continued, the public may view the daily sampling map, which can be accessed via the online status report on FWC’s Red Tide Current Status page. “For more information on algal blooms and water quality, please visit Protecting Florida Together,” FWC wrote.
In his Oct. 16 report on the Sarasota Bay Estuary Program (SBEP) website, Tomasko noted, “Satellites fly over Southwest Florida on a regular basis, and images are ‘processed’ by looking at specific wavelengths of light. For this tool, researchers in Ireland documented the abundance of a harmful algal bloom in northwestern European coastal waters caused by a species within the same genus (Karenia) as [the one that] causes our red tides. There are no sampling data to confirm the presence of red tide in these images, but in past years, this image processing algorithm has been highly accurate.”
He then wrote that, in his comparison of the two images above, it seemed to him “that there has been a fairly recent and substantial increase in the size of this red tide bloom.”
Anyone visiting the site whose link he had provided, above, can use the tools provided, Tomasko added, “to determine the shape of various signatures.
“As we’ve said for several years now,” Tomasko continued, “while it’s true that humans don’t ‘cause’ red tide, we can cause it to be worse. And while yes, it did rain a lot during the combination of August’s Hurricane Debby, September’s Hurricane Helene, and October’s Hurricane Milton, it should be remembered that it rained an awful lot on watersheds … Our best and most recent pollutant loading models suggest that under ‘average’ conditions, the nitrogen loads coming off of our watershed are about two to four times as high as they were when Florida was mostly undeveloped. So why would we be surprised to find that the rains, and wind damage, and storm surge of these most recent storms might load the eastern Gulf of Mexico with lots more nitrogen than otherwise would be the case?”
Later data
In an Oct. 22 follow-up on the SBEP website, Tomasko wrote, “Well, the last few days have provided evidence that the USF model was likely accurate. For example, if you compare the processed satellite imagery from October 18, 20 and 21 … we see evidence of a red tide ([FWC] samples have verified it is red tide) that has weakened over the past few days, as seen by a reduction of the areas of yellow and red at the expense of green and yellow. This suggests that the red tide, while still there, is not — at this time — strengthening. Nor does it appear to be making its way into our local bays. Which is consistent with the USF red tide forecast model. Our winds are [forecast] to continue to be out of the East to Northeast to North over the next few days, which should help keep this red tide away from our coast, and hopefully weaken it further.”
Tomasko added, “Fingers crossed, but we might be — once again — on the path to recovery.”