A massive toxic algae called red tide is killing sea turtles, sharks and fish in the northeast Gulf of Mexico and is threatening the waters and beaches that fuel Florida’s economy. Fishermen who make a living off Florida’s coast are reporting fish kills and reddish water. This particular strain of red tide, called Karenia brevis, is present nearly every year off Florida, but large blooms can be particularly devastating. Right now, the algae is collecting in an area about 60 miles wide and 100 miles long, about 5 to 15 miles off St. Petersburg in the south and stretching north to Florida’s Big Bend, where the peninsula ends and the Panhandle begins. Red tide kills fish, manatees and other marine life by releasing a toxin that paralyzes their central nervous system. The algae also foul beaches and can be harmful to people who inhale the algae’s toxins when winds blow onshore or by crashing waves, particularly those with asthma and other respiratory ailments. In 2005, a strong red tide killed reefs, made beaches stinky and caused millions 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, there is nothing anyone has been able to do about it. In the 1950s, wildlife officials tried killing the red tide algae by dumping copper sulfate on it, which made the problem worse in some ways. But some researchers are working to change that. Predicting when red tides are going to be especially bad can help fishermen and beach businesses prepare.
