Red Tide Off NW Florida Beaches Killing Marine Life


It’s Florida’s version of the Blob. Slow-moving glops of toxic algae in the northeast Gulf of Mexico are killing sea turtles, sharks and other fish, and threatening the waters and beaches that fuel the region’s economy.

Known as red tide, this particular strain — Karenia brevis — is present nearly every year off Florida, but large blooms can be devastating. The tide is collecting off St. Petersburg and stretching north to Florida’s Big Bend, where the peninsula ends and the panhandle begins.

Fishermen are reporting fish kills and reddish water. “It boils up in the propeller wash like boiled red Georgia clay. It’s spooky,” said Clearwater charter fisherman Brad Gorst.

Red tide kills fish, manatees and other marine life by releasing a toxin that paralyzes the animals’ central nervous system. The algae also foul beaches and can be harmful to people who inhale the toxins via onshore winds or crashing waves. Particularly at risk are those with asthma and other respiratory ailments.

In 2005, a red tide killed reefs, made beaches stink and caused millions of dollars in economic damage. A weaker red tide in 2013 killed 276 manatees, state records show, after infecting the grasses eaten by the endangered creatures.

“This red tide . . . will likely cause considerable damage to our local fisheries and our tourist economy over the next few months,” said Heyward Mathews, an emeritus professor of oceanography at St. Petersburg College who has studied the issue for decades.

Despite years of study, nothing has been found to counteract it. In the 1950s, wildlife officials tried killing the algae by dumping copper sulfate into the water, which made the problem worse in some ways.

Predicting when red tides are going to be especially bad can help fishermen and beach businesses prepare. But much of the information comes from satellite images, which are often obscured by clouds.

“In this particular red tide, we got a good image on July 23 — then we went weeks without another image,” said University of South Florida ocean scientist Robert Weisberg.

Weisberg is part of a team of researchers developing a prediction model based on ocean currents data rather than satellite images.

The model tracks currents that bring the natural nutrients, such as phytoplankton, that the red tide needs to gain a foothold. Unlike other red tide species, Karenia brevis is not believed to be caused by man-made pollution such as agricultural runoff, and historical accounts of what is believed to be the same red tide date back to the 1700s.

Using his method, Weisberg predicted in March the bloom that is now causing so much worry. It allowed state officials to issue a warning July 25.

Weisberg said the team is trying to develop a model that can look further into the future. But the tides often start far offshore, where gathering data and images can be time-consuming and expensive.

By Associated Press

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