Community Science Institute reports rising HAB reports on Keuka Lake, narrows 2025 sampling to priority public-supply sites

Grayson Scheidemanno, executive director of the Community Science Institute, told the Seneca County Board of Supervisors that the group’s volunteer monitoring on Keuka Lake and its tributaries recorded a record number of harmful algal bloom (HAB) reports in 2024 and that CSI will change its 2025 sampling protocol to focus laboratory analyses on priority locations identified by county health departments.

CSI’s monitoring program relies on trained volunteers who visually patrol shoreline zones and report blooms; the organization’s state-certified lab analyzes samples for cyanobacteria, chlorophyll a and microcystin toxin. Scheidemanno said CSI received 127 HAB reports in 2024 — the most since the program began in 2018 — and that more than half of tested blooms each year exceed New York’s contact-recreation microcystin guidance of 4 micrograms per liter in some samples.

"We will continue visual monitoring and reporting of HABs as…