As the sun set over Pass-a-Grille Beach on Wednesday night, the sky lit up with a remarkable display of pinks and oranges.
It was another dazzling December sunset for the books. But there were two caveats to an otherwise gorgeous night: the handful of dead fish scattered on the shoreline, and the slightly scratchy throat as Red Tide lingered offshore.
“It looks nasty today, and I do not anticipate any improvements in the near future because it appears that more Red Tide is heading shoreward from offshore,” Bob Weisberg, a physical oceanographer at the University of South Florida, wrote in an email to the Tampa Bay Times. “There are some odors on Tierra Verde where I live.”
As Red Tide has exploded across Southwest Florida in recent weeks — particularly near the counties hardest hit by Hurricane Ian — many in the Tampa Bay area who keep track of the harmful algal blooms, including Weisberg, have watched as they ebbed and flowed northward.
It’s not like last year, when crews cleared thousands of pounds of dead fish from Pinellas County shorelines, but as the scenes here in recent days have suggested, Red Tide is back.
Federal ocean scientists warned the public Thursday morning that some beaches in Pinellas, Manatee and Sarasota counties may have a moderate-to-high risk of respiratory irritation through Friday night. The advisory, issued by the National Centers for Coastal Ocean Science at 9 a.m., said the risk of respiratory irritation was possible for the next 36 hours.
At Pass-a-Grille Beach specifically, state water samplers detected a “medium” concentration of the Red-Tide-causing Karenia brevis organism Wednesday, according to the latest Florida Fish and Wildlife Conservation Commission data. At that level (between 100,000 and 1,000,000 cells per liter), fish kills are probable — and there’s a chance for respiratory irritation, the agency says.
“The bloom intensified in the last few days, got more nearshore and even intruded inside the bay,” said Chaunmin Hu, a professor of optical oceanography at the University of South Florida. When a bloom “intrudes” into Tampa Bay, that means the K. brevis organism has been detected at locations inside the mouth of the estuary, not just offshore in the ocean.
The state measured Red Tide blooms, which are defined as 100,000 K. brevis cells per liter or more, in 31 samples over the past week, according to the Florida wildlife commission’s midweek report. Twenty of those were in Sarasota County; four directly offshore the mouth of Tampa Bay, several miles into the Gulf of Mexico; four in Lee County; two in Manatee County and one in Charlotte County, the report shows. Officials were also monitoring reports of fish kills in Pinellas County.
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As of Thursday afternoon, the state had documented high bloom concentrations at Maximo Park on the southern tip of the peninsula and lower amounts at the Skyway Fishing Pier, according to the latest water-sampling data. The organism that causes Red Tide was detected as far north as Treasure Island Beach at medium levels offshore, with fish kills and breathing problems possible, according to the wildlife commission.
It’s not terribly unusual for low levels of Red Tide to be found in and around the Sunshine Skyway Bridge, according to Maya Burke, the Tampa Bay Estuary Program’s assistant director. When algae is detected in that area, it’s usually related to Red Tide.
Repeated Red Tide algal blooms year after year, such as what was recorded from 2019 through 2021, is “something no natural resource manager wants to see,” Burke wrote in an email.
“While fish, wildlife, and other environmental resources (like seagrasses) have historically been able to rebound from these episodic events, increasing frequency will chip away at their ability to bounce back,” Burke wrote. “These compound stressors are a challenge for maintaining a healthy Tampa Bay.”
Pinellas County’s environmental management team will ramp up water quality sampling starting next week and increase their trips to three days a week while the Red Tide bloom is offshore in the Tampa Bay area, according to spokesperson Tony Fabrizio. On Monday, the team found low Red Tide concentrations at two Fort De Soto locations . They were out again sampling Thursday morning, but results were not yet available as of the afternoon.
Over the next three days, the ocean currents on the bottom of the seafloor could move the offshore blooms closer to Tampa Bay’s coastline, according to Yonggang Liu, director of the Ocean Circulation Lab. The lab’s coastal forecast shows high amounts of Red Tide lingering along Pinellas County’s southern end through Sunday, with medium levels ranging as far north as the Madeira Beach and Treasure Island area.
“The bloom is getting worse near Tampa Bay’s mouth,” Liu said. “We are not optimistic for the next few days.”