Red tide is back: Causes & what could make it worse

Dead fish continue to wash ashore across southwest Florida. Red tide levels are high across many locations, causing more headaches for residents.

The red tide organism, Karenia brevis, was detected along Florida’s Gulf Coast. 78 samples showed K brevis was present offshore of Sarasota County. Lee County registered 13 samples with the toxic microorganism, with one sample in Manatee County, two in Charlotte County, and two in Collier County. The red tide was observed in areas as north as Santa Rosa County in Northwest Florida but as background concentrations, meaning very, very low.

Higher amounts of red tides can be tied back to Major Hurricane Ian and Hurricane Nicole. First, Major Hurricane Ian caused the upwelling of the water, causing the microorganisms to come up to the surface. Then, about a month later, Hurricane Nicole, which struck the east coast, brought winds onshore and pushed the red tides closer to the coast. In addition, Ian and Nicole produced big rain events (especially Ian), which caused lots of nutrient-rich runoff to head back into our oceans, which allows the toxic blooms to flourish. Fish kills were observed along Florida’s Gulf Coast. Any discharges of lake waters into the Gulf could be devastating for animals and residents and businesses.

Red tide causes lots of problems for marine life and humans. Besides fish kills, the toxic algae blooms can fill other wildlife, like manatees, and dolphins. The small toxic particles act as a paralyzer to marine life. Once in their system, their behavior is lethargic, and they start having problems breathing and die.

As the waves break up the harmful algae, the toxins get released into the air, causing a foul smell on beaches, nearby lakes, or canals. These toxins get into our breathing ways, also causing respiratory problems. These toxic particles can also cause breathing problems for our pets. Consuming fish or shellfish from red tide waters can be fatal for humans.

Red tide concentrations can last weeks, months, and over a year. It usually peaks during the late summer and early fall periods. The worse period Florida has seen was a long 30-month stretch from 1994 to 1997 and the longest most recent stretch (Top 5 in history) was 15 months from 2017 through 2019.