The new year has brought with it some improved red tide conditions to the Tampa Bay area as human health risks have declined in recent days. But it’s still something to keep an eye on, experts caution.
As of Tuesday morning, federal ocean scientists predicted a “low” risk for respiratory irritation from red tide blooms at just one location in the region: The Fort De Soto fishing pier, according to the National Centers for Coastal Ocean Science.
At that level, there’s a low chance you’d have respiratory symptoms like a scratchy throat or a runny nose, but people with chronic lung problems should leave the beach if they start feeling effects, according to the forecast.
Below: The latest red tide-related respiratory forecast for the National Centers for Coastal Ocean Science
The most recent red tide-tracking imagery shows “the situation has greatly improved for Tampa Bay,” according to Chuanmin Hu, a professor of optical oceanography at the University of South Florida. Hu uses satellites to monitor where the toxic algae are most concentrated, and images provided to the Tampa Bay Times show the dense blooms have mostly drifted south since Dec. 19.
“Most of the intense bloom is to the west and southwest of Anna Maria,” Hu wrote in an email to the Times Tuesday morning. “The pressure over St. Pete Beach and Madeira Beach has gone. But Anna Maria and Sarasota Bay may face new pressure.”
“Pressure” is another way of saying the potential for the worst impacts of any given red tide bloom event. In mid-December, hundreds of pounds of dead fish were cleared from popular St. Pete Beach destinations, including Pass-A-Grille Beach.
How did the conditions change?
Water samplers detected the organism that causes red tides, Karenia brevis, in 39 samples in and offshore of Southwest Florida last week, according to a Thursday update by the Florida Fish and Wildlife Conservation Commission.
Red tide bloom levels — or more than 100,000 cells per one liter of water — were found in 11 of those samples: Four in Pinellas County, four in Manatee and three in Sarasota. For Pinellas County, that’s an improvement. At least 18 water samples contained bloom levels over a one-week period in mid-December.
Pinellas County’s environmental management team was on the water Friday measuring red tide levels, according to spokesperson Tony Fabrizio. No Karenia brevis was detected in the stretch between Honeymoon Island to the north and Pass-A-Grille.
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“Conditions have improved off of Pinellas County, although there is still red tide present at low levels along the southern coast based on samples collected yesterday,” wildlife commission spokesperson Carly Jones wrote in a statement to the Times.
Although the worst blooms are currently sitting offshore of the Bradenton and Sarasota area, surface currents are projected to shift in the coming days. That means the blooms could be pushed to the north, back near the mouth of Tampa Bay, according to Jones. A multi-day research survey between several agencies is starting later this week to sample Gulf of Mexico waters.
The shift of the worst red tide to the south in the past several days can be explained by how the ocean has interacted with the wind during recent cold fronts, according to Yonggang Liu, director of the Ocean Circulation Lab.
Wind-driven ocean circulation can move water on the surface, including red tide, away from the coast. But that battles with the currents along the bottom of the seafloor that can bring blooms closer to shore. (These blooms can often be tricky to forecast.)
“Red tide concentrations and aerosols can vary almost daily based on the winds and the currents when there is a bloom nearby,” Fabrizio wrote in an email to the Times. “So we’ll need to continue to monitor for changes.”
Below: The latest red tide water samples from the Florida Fish and Wildlife Conservation Commission.