Outdoors

Red Tide bloom still mysterious

By RODNEY PAGE
Published July 24, 2005

Here is the good news about Red Tide: The concentration levels of the alga that cause the bloom are down slightly in most of Tampa Bay. Here is the bad news: The levels are still high enough that fish kills remain prevalent in area waters. And worse news: Levels were reported higher around Mullet Key (Bunces Pass) off Fort De Soto.

Fish kills were reported offshore of Anclote Key in southern Pasco County, along coastal areas of St. Pete Beach, around Apollo Beach, the Little Manatee River, Port Manatee and the south Skyway Fishing Pier.

Westerly winds are forecast through the weekend, which may increase Red Tide effects along coastal areas.

So to answer the question on most coastal resident's minds: Researchers don't know when the bloom will dissipate.

"People want a crystal ball and we don't have it," said Cindy Heil, senior research scientist for the Florida Marine Research Institute in St. Petersburg. "We haven't had a bloom like this since the mid 1970s, so we don't really have anything to compare it to. And there are huge variables from year to year. It's really an open end of research."

This bloom began in January, according to Heil. It originated about 25 miles off St. Pete Beach and slowly worked its way to the shoreline. This bloom is separate from the one that cropped up near Fort Myers and Sarasota in the spring and early summer.

Red Tide is caused by a higher than normal concentration of a microscopic alga, or plant-like organisms. In Florida, where Red Tide is most prevalent, the likely cause is Karenia brevis. The organism produces a toxin that can affect the central nervous system of fish.

At high concentrations, called a bloom, the organisms may discolor the water, which is where the term Red Tide comes from. But the water can also appear greenish, brownish or even purple. Sometimes the color is unchanged.

It takes about 5,000 cells of the organism per liter to start a bloom. About 50,000 cells causes fish kills. About 1-million turns the water red.

Beach residents or sunbathers could not care less about all that. The only thing that matters is there are dead fish and it stinks worse than rotten eggs.

"This is unusual in that it started in the winter," Heil said. "It continued to spread from about north of Sanibel to the mouth of Tampa Bay, then up into the bay. (The blooms) usually begin in August or September. We're not really in the start of bloom season yet."

Great.

Heil said scientists aren't sure what starts or ends a bloom beyond a diminishing growth of nutrients for it to feed on. How that happens, Heil said, is being researched.

Heil recommends that those catching edible fish should eat only the filets and throw the rest out. Make sure the filets are cleaned thoroughly before eating. Stay away from fish exhibiting unusual behavior.

Shrimp are not affected, but shellfish may be contaminated.

As for the beach, Heil recommends people check the wind before heading out. She suggests people take an antihistamine before entering the water. Those with asthma problems should steer clear.

"There is very little known as to what might cause an end to the bloom," Heil said. "But we are monitoring this bloom intensely."

[Last modified July 24, 2005, 00:22:18]