Cyanobacteria Information


Visual inspection of the water at Indian Brook detected small clusters of cyanobacteria (blue-green algae) along the shoreline on Thursday, July 29th. The VT Dept of Health has advised that parkgoers take caution and do not swim (including dogs) as a precaution, until further notice.

Cyanobacteria, also known as blue-green algae, are naturally found in freshwater in the U.S., and in Lake Champlain and other Vermont waters. Some types of cyanobacteria can release natural toxins or poisons (called cyanotoxins) into the water, especially when they die and break down.

Cyanobacteria grow well in water that has high amounts of nutrients like phosphorous and nitrogen. Cyanobacteria can multiply quickly to form surface scums and dense populations known as blooms, especially during the warm days of late summer and early fall. In recent years, cyanobacteria blooms have occurred most often in northern sections of Lake Champlain—such as St. Albans Bay and Missisquoi Bay.

Since 2003, the Lake Champlain Committee (LCC)(link is external) has trained citizen volunteers to monitor for cyanobacteria at lakeshore locations. Volunteer monitors, along with staff from the Vermont departments of Health and Environmental Conservation, file weekly online reports that are then displayed on the Cyanobacteria Tracker Map. The program helps citizens, along with health, environmental and recreational officials, assess the safety of our beaches. It also provides important data to help us further understand when and why blooms occur.

Vermont Cyanobacteria Tracker

How to Identify Cyanobacteria

If you have a concern or observe Cyanobacteria at Indian Brook please send pictures and location information to will help our staff visually confirm from the pictures as well as visit the location at the park. From here testing may or may not occur base on suspicion of Cyanobacteria. Thank you! Cyanobacteria Image