Red tide through the decades: Still a mystery

ST. PETERSBURG, Fla. - Florida summers are remembered for many things, both good and bad. On our coast, they're sometimes remembered for red tide. 

In the summer of 1971, the Rolling Stones were singing "Brown Sugar" and the Bay Area was awash in one of the worst red tide blooms on record.

"There was an enormous smell of dead fish, not only on the gulf side where the beaches are, but also on the bay side," recalled retired FOX 13 meteorologist Andy Johnson, whose family lived in Indian Rocks Beach at the time.

Johnson said boaters stayed in and businesses suffered. Like hurricanes, the naturally-occurring red tide is an inevitability of life on the gulf coast.

Red tide FAQ: What is it, and where does it come from?

State researchers say accounts of red tide events date back hundreds of years, to the first arrivals of Europeans in Florida. But a bloom in 1947 may have been the first time it was called red tide - by a charter captain quoted in a newspaper.

"We had it back in the '60s and '70s," said oceanographer Dr. Heyward Mathews, professor emeritus at St. Petersburg College.

Mathews studied red tide when he was a student in the 1960s, but its cause remains the subject of debate a half-century later.

"It would be nice if we could say, 'every seven years' or 'El Nino' or something like that," said Mathews, but so far researchers haven't found any pattern.

The bloom just appears, like the red tide of 2005 which created what was called a "dead zone" off Clearwater Beach.

Mathews said tons of decomposing fish on the ocean floor robbed the water of oxygen, killing everything to the surface.

Mathews says 2005 was one of the worst blooms he's seen, but he has no idea how bad the next one will be or how long any of them will continue.