MAYVILLE — The Chautauqua County Health Department’s Public Health Division has noticed isolated harmful algal blooms in the south basin of Chautauqua Lake.

Residents and visitors are asked to educate themselves about harmful algal blooms and to be cautious when swimming, boating and fishing. In New York, harmful algal blooms occur most frequently in the mid- to late-summer months but can occur at any time of the year. Small bloom conditions can change rapidly due to changes in weather and lake currents. Larger blooms will likely persist throughout the summer once they become established.

Blue-green algae, also known as cyanobacteria, are naturally present in lakes. Nutrient rich runoff from surrounding land, warm water temperature, and sunshine encourages blue-green algae growth. With the right conditions blue-green algae forms blooms which may appear as floating “rafts” or scums on the surface of the water.

The public should be alert and watchful for blooms which may resemble “pea soup” or have a paint-like appearance with strong colors including blue-green, green, yellow, white, brown, purple, or red. Blooms are more likely in nearshore areas than open water areas.

Harmful algal blooms present a public health risk because they can release toxins which may be harmful to human and animal health. People and pets can be exposed to toxins by contact (touching, swallowing, and inhaling water droplets) with HABs during water recreation activities, through surface water use around the house, such as watering gardens, and through improperly treated drinking water. Municipal water treatment facilities in Chautauqua County do test for toxins in lake water as part of the treatment process.

“Not all blooms are hazardous, but the Health Department recommends taking the following precautions,” said Christine Schuyler, county director of Health and Human Services. “When swimming, wading, or boating, avoid areas with blooms or surface scums, or water that is noticeably discolored. This applies to everyone – adults, children, and animals. Don’t fish or eat fish caught from areas with blooms or surface scums, or water that is noticeably discolored. Pay attention to beach closures, advisory signs, press releases, and websites. Never swim at beaches that are closed. Never drink, prepare food, cook, or make ice with untreated surface water, bloom or no bloom.”

If people or pets are accidentally exposed to a bloom use clean water to rinse off as soon as possible. Consider medical attention if people or pets have symptoms including diarrhea, nausea or vomiting, skin irritation, and allergic reactions or breathing difficulties after exposure to surface waters with HABs.

New York state and Chautauqua County have active programs aimed at reducing the amount of phosphorus and nitrogen entering streams and lakes. Watershed management plans have been developed for several lakes in Chautauqua County, including Chautauqua and Findley. As recommendations in the plans are implemented, improved water quality will follow, but it may take years to see improvements.

The state Department of Environmental Conservation and Department of Health investigate harmful algal bloom reports, samples blooms for toxins and conducts research to learn more about HABs and toxin production.

The Chautauqua County Health Department monitors permitted bathing beaches for harmful algal blooms and the indicator bacteria E. coli. To best protect the public from possible illness, beaches are closed when the water exceeds bacteria safety standards and/or harmful algal blooms are identified. Weekly updates are planned throughout the summer to alert residents of changes in the status of harmful algal blooms in the county. The current status of Chautauqua County permitted public beaches and additional information about harmful algal blooms are listed on the county website at chautauqua.ny.us/246/Beach-Closings.