Red tide is improving around Tampa Bay and Anna Maria Island, but hangs on near South FL

File photo by Tiffany Tompkins/

A bloom of the toxic algae known as red tide has swept the coast of Southwest Florida since October, but its presence is weakening around Tampa Bay, Bradenton and Sarasota area beaches.

In more good news for vacationers and beachgoers, conditions are favorable for the bloom to keep receding in the coming weeks, according to Yonggang Liu, director of University of South Florida’s Ocean Circulation Lab.

The algae bloom’s presence is not only weaker near shore, but also out in the Gulf of Mexico, where the university is observing surface water conditions with a glider this week. On Wednesday, the glider was about 36 miles offshore from Clearwater.

“There is no elevated chlorophyll concentration out there,” Liu said in an email. “This is a good sign for us.”

Recent cold fronts paired with the Gulf of Mexico’s Loop Current currently hugging the west Florida shelf have worked to churn the water and dilute red tide’s presence in the Tampa Bay area. Without more algae present offshore to feed the bloom, it will likely continue to dissipate, Liu said.

One unknown factor is how much red tide is present in deep waters offshore, where satellites cannot observe.

“For the next few weeks, the bloom may gradually weaken if there are not much new red cells at depth offshore,” Liu said.

Meanwhile, the bloom’s presence has grown stronger farther south this week offshore of Lee County, where very low to high concentrations were observed in samples collected by the state.

The “complicated” shape of the coastline in the Sanibel Island area means that red tide often lingers there for a longer duration, Liu explained.

Recent satellite imagery revealed a large patch of chlorophyll off the coast of South Florida, but scientists have not yet determined whether it contains a large amount of red tide algae. A scientific cruise is scheduled to observe the patch next week and see what it contains.

Red tide levels drop on Florida’s Gulf Coast

Overall, red tide levels have dropped dramatically for much of Florida’s Gulf Coast over the last three weeks, samples collected by the Florida Fish and Wildlife Conservation Commission and partners show.

Bloom concentrations, or red tide levels of medium and above, were only detected in 12 samples along the Southwest Florida coast this week, most of them off of Lee County.

That compares to 102 samples at bloom level last week and 89 the week prior.

Bloom levels that had persisted in waters off of Manatee County near the mouth of Tampa Bay were not found this week. Very low levels were observed in two samples near the north end of Anna Maria Island, and low levels were observed in several samples near the Sunshine Skyway Bridge.

Off of Sarasota County, one low level sample was taken near New Pass, and one very low sample was taken at the Venice Fishing Pier.

Despite the dropping levels, respiratory irritation was reported at several beaches in Manatee and Sarasota counties over the last week, as well as reports of dead fish in Sarasota County.

Red tide forecast

The National Oceanic and Atmospheric Administration forecasts the respiratory threat from red tide.

On Wednesday, NOAA warned of possible respiratory irritation over the next 36 hours on some beaches in Manatee, Sarasota, Charlotte, Collier and Monroe counties when winds are blowing onshore.

A moderate risk was forecast in Pinellas County near Fort De Soto State Park and Pass-a-Grille Beach.

University of South Florida’s red tide-tracking forecast predicts minimal presence of red tide around Tampa Bay, Anna Maria Island and coastal Manatee County into the weekend.