Red Tide is Back

On July 25, 2014, the Florida Fish and Wildlife Conservation Commission (FWC) reported that a bloom of red tide was confirmed in samples collected offshore of Hernando County. Citizens had been calling FWC’s Fish Kill Hotline to report observations of thousands of dead and dying bottom dwelling reef fish, including grouper, hogfish, white grunt, triggerfish and snapper, as well as sea turtles and crabs. The fish kill, stretching from Pasco to Dixie counties, is being blamed on red tide.

FWC Law Enforcement took scientists to collect fish, water samples and water quality data from six locations offshore of Hernando County on July 23rd. Sample analysis confirmed a bloom of the Florida red tide organism, Karenia brevis. This organism naturally occurs in the gulf and has been around since the 1700s. Red tides occur when microscopic algae multiply to higher than normal concentrations often discoloring the water. They are known to form many miles offshore, sometimes causing no impact to humans. In other cases they may be blown inshore and cause respiratory irritation among beachgoers.

Satellite images were taken using the University of Florida’s Optical Oceanography Lab. They confirmed that the bloom had spread to an area about 50 miles wide and 80 miles long located between 40 and 90 miles from the shore. Short term forecasts of bloom movement by the Center for Prediction of Red Tides do not predict considerable movement of the bloom patch in upcoming days.

Mote scientist will be conducting a water sampling survey on July 31, between Sarasota and the southern edge of the bloom to learn more about it and the physical conditions surrounding it. Based on these results, Mote’s Ocean Technology Program plans to deploy “Waldo,” an autonomous underwater vehicle to sample for physical conditions and the presence of K. brevis using a red tide detector. Another glider from the University of South Florida will likely be deployed simultaneously to increase the region that can be surveyed.

An update from the National Oceanic and Atmospheric Administration on July 28, said the current bloom is not expected to cause respiratory irritation alongshore of southwest Florida through Monday, August 4th.

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