Wednesday, January 26, 2022

Red Tide: What You Need to Know



Southwest Florida residents were concerned to learn that a bloom of the Florida red tide organism, Karenia brevis (K. Brevis) has been observed locally. But what exactly is red tide, and what can you do to protect yourself? What is Red Tide?

A red tide, or harmful algal bloom, is a higher-than-normal concentration of a microscopic alga (plantlike organism). In Florida and the Gulf of Mexico, the species that causes most red tides is Karenia brevis (K. brevis). At high concentrations, Florida red tide can discolor water a red or brown hue. The water can also remain its normal color during a bloom. Where is Red Tide Found?

K. brevis cannot tolerate low-salinity waters; blooms usually remain in salty coastal waters. Red tide can be found in Florida’s bays and estuaries, but not in freshwater systems (lakes and rivers). Current Reports



K. brevis was found in background to high concentrations in twenty-one samples collected from Lee County, background to medium concentrations in five samples collected from Charlotte County, and very low concentrations in one sample collected from Collier County. Background concentrations were also found in one sample collected from Manatee County, and background to low concentrations in fourteen samples collected from Sarasota County.

The effects have been reported in smallscale fish kills along Charlotte and Lee counties and slight respiratory irritation in Lee County. Collier County Pollution Control says that, “no respiratory irritation or dead fish have been reported” in the county. Health Concerns



The concern with red tide is that many produce toxic chemicals that can affect both marine life and humans. K. brevis produces brevetoxins that can affect the central nervous system of fish and other vertebrates, killing them. Waves can break open K. brevis cells and release these toxins into the air, leading to respiratory irritation. For people with severe or chronic respiratory conditions, such as emphysema or asthma, red tide can cause serious illness. The red tide toxins can also accumulate in molluscan filter-feeders (oysters and clams), which can lead to Neurotoxic Shellfish Poisoning in people who eat the contaminated shellfish.

Although there have been no reports of respiratory irritation in Collier County, the forecast is that red tide is still present to our north and northerly winds could push red tide into the county. Therefore, people with asthma, emphysema and other respiratory conditions should exercise caution when going to the beach. Is Swimming Safe?

For most beach-goers, swimming is still safe. However, some people may suffer from skin irritation and burning eyes when red tide is present. Those who already have respiratory illnesses may experience respiratory irritation in the water. It has been recommended that if you are susceptible to irritation from plant products, to avoid areas with red tide bloom. Also, if you experience irritation, you should get out of the water and thoroughly wash off. Another piece of advice is to avoid swimming among dead fish because they can be associated with harmful bacteria. Can I Eat Seafood?

The red tide toxin cannot be seen or tasted, and is not destroyed by cooking or freezing. During a bloom you may still eat seafood, just choose your seafood carefully following safety guidelines.

Store-bought and restaurant-served shellfish, monitored by the government for safety, are safe to eat during a bloom. Commercially available shellfish are often not locally harvested and, if harvested locally, are tested for red tide toxins before they are sold. It is safe to eat local finfish as long as they are filleted, because any toxins in the guts of the fish are disposed of.

Recreational harvesting of bivalve mollusks (hard clams, oysters and mussels) from conditionally approved or approved shellfish harvesting areas is banned during red tide closures and these organisms should not be eaten. Edible parts of other animals commonly referred to as shellfish (crabs, shrimp and lobsters) are not affected by the red tide organism and can be eaten, but do not eat the tomalley. During scallop season, locally harvested scallops from open scallop harvesting areas are safe to eat as long as you eat only the muscle of the scallop and not the whole animal.

Illegally harvested and unregulated shellfish are dangerous and should never be consumed. Coquina clams and molluscan predators (such as whelks) readily accumulate toxins in their tissues. Avoid eating animals found dead or distressed, especially in a red tide area. Take Care of Pets

Pets may also be affected by red tide. If you live near the beach, consider bringing your pets inside during a red tide bloom. If you and your pet are at the beach, do not allow them to play with dead fish or foam. If your pet swims in the red tide, wash it as soon as possible so they don’t lick themselves and consume toxins from their fur. Can Red Tide be Predicted/Controlled?

A red tide occurrence cannot be predicted, but once a bloom is located scientists can forecast its movement using date on wind and water current. Scientists routinely monitor the concentration of the red tide organism by collecting water samples.

Potential controls to red tide must kill both the red tide organism and eliminate the toxins from the water. Presently, there is no way to control or kill red tide blooms. Who to Contact

To report dead fish or red tide symptoms call Collier County Pollution Control at 239-252-2502. To speak to a health professional regarding red tide symptoms call the Florida Poison Information Center toll free at 1-800-222-1222. Red Tide Hotline

Collier County Red Tide Updates are available on the Red Tide Hotline at 239-252- 2591, an automated recording with the most recent Red Tide information for Collier County available 24 hours a day, 7 days a week. For More Information

Collier County Red Tide Updates:

NOAA Harmful Algal Bloom

Operational Forecast System (HABOFS): tidesandcurrents.noaa. gov/hab/gomx.html

Algal Blooms and your health aquatic-toxins/index.html

The FWRI HAB group and Mote Marine

Laboratory on Facebook: Florida Red Tide and other Harmful Algal Blooms (HABs)

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