Eco-Economics

Fearful of bad publicity, some Gulfshore residents and business owners choose to avoid open discussion of red tide. The intense algae blooms, which yield piles of smelly, dead fish at the beach and potential health risks, do little to attract visitors to the region's coastal establishments. One estimate suggests that on average, red tides in south Florida annually result in tourism-related losses totaling some $20 million. When costs of cleaning up dead fish, fisheries loss, health care, monitoring and research are added, the economic impact of red tide rises even further.

"Everybody is complaining that this year was bad," says Maria Furetta, owner of Buongustaio restaurant in Naples. "We're concerned about our children's health and the impact on business."

But now some local leaders have decided it is better to inform people and look for ways to lessen the economic, health and environmental impact of red tide through research and education. "Water quality is critical to our residents, businesses, tourism and economic development," says Meg Judge, chairman of the Estero Chamber of Commerce.

Inspired by Judge's concerns, and similar worries of Lee County commissioner Ray Judah and Collier County commissioner Jim Coletta, scientists working on red tide in the region recently convened at Florida Gulf Coast University in Estero to discuss what more could and should be done. The meeting, organized by the University of Miami's Rosenstiel School of Marine & Atmospheric Science and Sarasota's Mote Marine Laboratory, drew researchers who are currently studying why some outbreaks of red tide persist longer than others, how to better predict and mitigate red tides, what the health risks are and whether there are appropriate treatment and prevention methods. One idea that emerged from the meeting: the need for a regional clearinghouse to provide the public, business, media and scientists access to timely and comprehensive information.

Red tides have been occurring here since at least the 1840s. Usually they take place relatively infrequently and are short-lived. Days after an event, the beaches are safe for all to enjoy. But throughout the past 100 years, there have been periods in which red tides have lasted for weeks to months. A particularly bad episode occurred in the 1950s. This year has been similar, with red tide lasting off and on for weeks at a time.

Red tides are the result of an intense and rapid reproduction-or bloom-of small, single-celled algae. The water can become discolored, often red, due to high concentrations of the algae. Blooms of red tide typically occur in late summer and autumn, beginning offshore and moving toward the coast. Scientists currently have a poor understanding of what triggers and halts red tides. Blooms can be a natural phenomenon, but one question of particular interest is whether human influences are causing blooms to occur more frequently, spread, intensify or stay longer. Red tide is a natural component of the ocean ecosystem; the main problem is that they contain a toxin.

The local red tide alga, Karenia brevis, is relatively fragile. Waves easily break it up and cause the toxin to be released into the Gulf. Like other harmful algal blooms, red tides may also create dangerously low oxygen conditions near the seafloor as large amounts of organic matter sink, decompose and use up oxygen. Red tide toxin or low oxygen conditions at the seafloor can cause massive kills of fish, birds and marine mammals. Wave action causes the toxin to become aerosolized, whereby onshore winds may carry it onto the beach and inland.

Scientists also want to answer questions about red tide and human health. So far, research suggests that fillets of fish from red-tide waters appear safe. But ingestion of contaminated shellfish can result in food poisoning; symptoms typically include nausea, diarrhea and abdominal pain. More severe reactions are possible, but less common. Because shellfish beds are well monitored in Florida, there haven't been any cases of related food poisoning from commercially caught shellfish. The risks associated with swimming in red-tide waters remain uncertain, though some children have developed rashes. Inhalation of tainted sea spray can cause respiratory distress and more severe reactions in asthmatics, the elderly and those with respiratory illness.

Many of those concerned about red tide want a smoking gun-something or someone to blame. Unfortunately, there's a lot of misinformation and misunderstanding out there. Have humans altered the marine ecosystem and contributed to the problem? Unquestionably, but can we pinpoint one specific problem? No. Contributing factors could include global warming, runoff high in nutrients and contaminants, and overfishing. Changes in the flow of ocean currents, river input or climate may also play an important role in red-tide events. In all likelihood, it is a combination of factors, both natural and manmade, that affects how often and for how long Southwest Florida experiences red tides each year.

Business owners, residents and tourists alike have their fingers crossed that our visiting red tides will stay briefly and come less frequently in the future. Gulfshore residents and businesses rely on, value and appreciate the region's beaches and bays. Our best bet to reduce the economic and health consequences of red tide is to invest in improved monitoring, education and research aimed at better understanding its causes. We also must learn how to mitigate its impact and help the local community to deal with its effects by discussing the issue openly, particularly so that those with respiratory ailments, such as asthma, know when red tides are here.

Naples resident Ellen Prager, Ph.D., is an earth and ocean scientist and author.