What is a Florida red tide?

A red tide event is caused by a higher than normal concentrations of a microscopic plant-like organism called algae. In Florida, the Karenia brevis or K. brevis species causes most red tides events. This organism produces a toxin affecting the central nervous systems of fish. At high concentrations these microscopic organisms may discolor the water. However, red tide events do not always discolor the water. Further, even if the algal

bloom discolors the water, the discoloration is not always red. Often the coastal waters may appear greenish, brownish, and even a hue of purple in color.

For a listing of frequently asked questions regarding red tide, please visit the Florida Marine Research Institute’s red tide FAQ page.

Health Concerns

Red tide may pose serious health risks to individuals suffering from severe or chronic respiratory condition. Therefore individuals suffering from these conditions are cautioned to avoid areas experiencing red tide events, for the duration of the red tide bloom. Red tide may also negatively

affect individuals not suffering from any respiratory illnesses. These health affects often come in the form of varying degrees of eye, nose and throat irritation similar to cold symptoms. When the individual leaves the red tide area, symptoms usually cease. These symptoms are caused by the fact that as red tide blooms approach coastal areas, breaking waves may cause the toxin to become mixed with sea spray and disperse the toxin.