Red Tide FAQ

 Red tide, a naturally occurring phenomenon, is a high concentration of a microscopic alga in the water. Learn all about this occurrence, its side effects and how it impacts your vacation time in Florida!

1.      What is red tide?

Red tide occurs when there is a high concentration of a microscopic alga in the water. In Florida, the species of algae that causes most red tides is called Karenia brevis. Karenia brevis produces a toxin that can affect the central nervous system of fish. At high concentrations, the organisms may discolor the water. Red tide is not, however, always red. Red tide can often appear light to dark green to brown. The water can even remain its normal color!

2.      What causes red tide?

Red tide is a natural occurrence not caused by human beings. When temperature, salinity and nutrients reach certain levels, an increase in Karenia brevis algae occurs. No one knows the precise combination of factors that causes red tide, but some experts think high temperatures combined with a lack of wind and rainfall is usually at the root of red tide blooms.

3.      How long does red tide last?

Red tide can last anywhere from a few days to a few months. It can also change daily due to wind conditions. Due to this, it is important to contact your local area for accurate and current water conditions.

4.      Is it safe to swim during red tide?

For most people it is completely safe to swim during red tide. For some, however, red tide and cause skin irritation and burning eyes. If you are particularly vulnerable to irritation from plant products, stay out of red tide water. If you begin to experience irritation, get out of the water and wash off. Never swim among dead fish because they can be linked with harmful bacteria.

5.      How are people with respiratory conditions affected by red tide?

People experience respiratory irritation when the red tide organism is present along a coast and winds blow its poisonous aerosol onshore. Due to this, people with severe or chronic respiratory conditions (bronchitis, asthma, emphysema) should avoid red tide areas as it will make their symptoms (coughing, sneezing, tearing) worse. Symptoms will typically dissipate within hours, especially if you go to an air conditioned facility.

6.      While I’m visiting Florida I want to enjoy fresh seafood! Is it safe to eat seafood during red tide?

Yes and no. Commercial seafood, including shellfish, from local restaurants, grocery and seafood stores must be harvested from red-tide free waters. If you are fishing on your own, however, one must avoid shell fish, including clams, oysters and whelks as they are not safe to eat. Although crabs, shrimp and lobsters are typically called shellfish, they are not affected by red tide and are safe to consume.

7.      Does cooking destroy the red tide toxin?

No!