There's always some red tide in Gulf waters, usually at low concentrations, but sometimes the single-celled algae bloom massively. That has been the case most of this year, with the red tide paying beach visits from Naples to Pinellas County when the wind is right.
On Longboat Key, crews picked up dead fish for five hours Tuesday. Over the weekend, workers used a machine to rake up dead fish on the public beaches in Venice. On Siesta Key, rotting fish chased snorkelers out of the water while an acrid smell hung in the air.
Red tide can also give some beachgoers coughing fits and itchy eyes. Testing by Sarasota's Mote Marine Laboratory found high concentrations of red tide in Sarasota Bay on Monday and moderate amounts off the beaches.