Manatee County, AMI waters free of red tide blooms

After months of fish kills and sometimes smelly beaches, red tide conditions that affected waters around Anna Maria Island and Manatee County have receded — for now.

Karenia brevis, the organism that causes the harmful algal bloom known as red tide, was not present in any of the latest round of local water samples collected by the Florida Fish and Wildlife Conservation Commission and its partners. It’s the first time since April that the organism has not been detected at significant levels in Manatee County waters.

Dead fish and respiratory irritation have also stopped fouling beach conditions on Anna Maria Island, according to Mote Marine Laboratory’s beach conditions tracker, which is updated by lifeguards.

Red tide algae is naturally occurring in Tampa Bay and the Gulf of Mexico. The blooms typically start in the late summer or fall in offshore waters, according to FWC. However, if the blooms move into coastal areas, they can be sustained and possibly worsened by human-caused nutrient pollution.

Severe blooms are a cause of concern for numerous reasons, including negative impacts on tourism, recreation and seafood harvesting. The blooms can deplete oxygen from the water column, killing or driving away marine animals, and block sunlight needed by marine plants like seagrasses, which are crucial to ecosystem health. K. brevis also produces powerful nuerotoxins known as brevetoxins that can kill fish, marine mammals and birds and make humans sick.

08/07/21—Red tide brought dead fish to the canals of Coral Shores in Bradenton this summer. Tiffany Tompkins [email protected]

Active year for red tide in Southwest Florida

Red tide bloom conditions have persisted in Southwest Florida since December, when medium and high levels of the algae were first detected near Lee and Collier counties. By March, low concentrations of red tide algae were showing up off of Charlotte and Sarasota counties, and in April it cropped up around Anna Maria Island and lower Tampa Bay.

The algae lingered in Tampa Bay, and by June, an untimely and severe red tide bloom had developed throughout the region. It was roughly two months after the Florida Department of Environmental Protection approved the release of 215 gallons of contaminated water into the estuary from the Piney Point industrial site in Manatee County. The release was approved to prevent a catastrophe on land, where the largest retention pond at the former phosphate processing plant threatened to break and flood surrounding homes and businesses with contaminated water.

While scientists continue to study the impact of the Piney Point discharge on Tampa Bay, they say its nutrient-rich water could have likely helped fuel the harmful algal blooms of red tide and Lyngbya, a blue-green algae, that followed.

The red tide event hit Pinellas and Hillsborough counties especially hard, driving crowds away from beaches and killing massive amounts of marine life, including more than 1,800 tons collected in Pinellas since the bloom began. While red tide has since dissipated in bay waters around both counties, it remains strong in some spots along Pinellas’ Gulf coast.

South of Manatee, Sarasota County’s coastline also suffered long lasting effects of red tide tide. But according to the most recent samples, the algae has nearly retreated there as well.

Compared with surrounding counties, Manatee experienced milder impacts from its most recent bouts with red tide. Red tide lingered at varying levels throughout the late spring and summer, offshore and near the coast. It reached its height around Anna Maria Island in July and August, when smatterings of dead fish washed ashore and health warnings were issued for some beaches.

By early August, more than 40 tons of red tide related material, including dead sea life, had been collected from area beaches and sent to the landfill. Blooms reached “high” levels, or more than 1 million cells of K. brevis per liter, for several weeks around the island before beginning to taper off again. Conditions have continued to improve over the last several weeks.

FWC is expected to release its next red tide update Friday.

Ryan Ballogg is a news reporter and features writer at the Bradenton Herald. Since joining the paper in 2018, he has received awards for features, art and environmental writing in the Florida Press Club’s Excellence in Journalism Competition. Ryan is a Florida native and graduated from University of South Florida St. Petersburg.
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