Letter from Holly Waterfield

HAB Identified in Otsego Lake

A bloom of cyanobacteria (“blue-green algae”) was detected on Otsego Lake at the SUNY Oneonta Biological Field Station Boathouse (6 Mile Point, near Sunken Island) around 9:30 a.m. on July 10, reported by Paul Lord. It was later confirmed by Kiyoko Yokota to be composed of Microcystis aeruginosa, the same species as in the 2022 and 2023 cyanobacterial blooms or cHABs (cyanobacterial harmful algal blooms) in Otsego Lake. Samples have been collected for in-house microcystins (a type of toxins produced by cyanobacteria) testing at BFS, results will be available soon.

Lake users should use caution and check the water conditions prior to use, as bloom conditions are known to change quickly. Keep watch along the shoreline and at the surface in protected areas (boat slips, small coves, etc.). Avoid discolored or cloudy water, green streaks, foamy accumulations, etc., as these areas may contain cyanobacteria and the associated toxins. Pets are particularly vulnerable. At the time of shoreline sampling HAB conditions were present or developing at 5 Mile Point and the Thayer Boathouse in protected areas around the docks and shoreline.

If you see suspicious conditions, report it to the New York State Department of Environmental Conservation HABs Program via the online report tool (https://dec.ny.gov/environmental-protection/water/water-quality/harmful-algal-blooms/notifications#Report).

For context with regard to swimming areas, according to the Department of Health, regulated swimming beaches are closed based on visual indication of a bloom and re-opened after the bloom has dissipated (visual assessment) and the total microcystin concentration is less than 4 ug/L in a sample collected the following day. To learn more, visit https://www.health.ny.gov/environmental/water/drinking/bluegreenalgae/bga_bathingbeaches.htm.

Holly Waterfield, CLM
SUNY Oneonta Biological Field Station

Editor’s Note: A harmful algal bloom was also detected in Canadarago Lake on Saturday, July 13. The Canadarago Lake Improvement Association advised residents on its Facebook page to exercise caution and avoid contact with the water until further notice.