Confirmed harmful algal blooms have been reported on Cayuga and Otisco lakes since the July 4 weekend, according to current HAB report data.
The reports show three confirmed blooms on Finger Lakes waterbodies between Friday, July 3, and Monday, July 6. Two were reported on Cayuga Lake in Cayuga County, while one was reported on Otisco Lake in Onondaga County.
All three Finger Lakes reports were listed as “small localized” blooms. No widespread or lakewide bloom reports were included for Finger Lakes lakes during that post-holiday period.
Cayuga Lake had two confirmed reports
Cayuga Lake accounted for two of the three Finger Lakes reports in the data.
The first was observed at 12:51 p.m. Friday, July 3, in Cayuga County. It was reported by the Community Science Institute and listed as a confirmed, small localized bloom.
A second Cayuga Lake report was observed at 4:45 p.m. Monday, July 6, also in Cayuga County. That report was also submitted by the Community Science Institute and listed as confirmed and small localized.
The two Cayuga Lake observations were reported from nearby coordinates, suggesting the reports were concentrated in the same general area rather than spread across the lake.
Otisco Lake bloom reported Sunday
Otisco Lake had one confirmed HAB report during the same period.
That bloom was observed at 12:43 p.m. Sunday, July 5, in Onondaga County. It was reported by the Otisco Lake Preservation Association and listed as confirmed and small localized.
Otisco is one of the eastern Finger Lakes and has seen HAB activity in past seasons. The latest report does not indicate a lakewide issue, but it does show conditions were favorable for at least one bloom shortly after the holiday weekend.
Regional reports remain localized
The broader report list included one additional Central New York bloom after July 4: a confirmed, small localized HAB at Jamesville Reservoir in Onondaga County. That report was observed at 8 a.m. Sunday, July 5, and submitted by the state Department of Health.
Taken together, the data points to localized HAB activity rather than a widespread regional bloom event. Every report since the holiday weekend was confirmed, but every one was also classified as small localized.
That distinction matters. A small localized bloom can still pose a risk to people and pets who come into direct contact with affected water, but it does not mean an entire lake is unsafe.
HABs can appear quickly and move with wind, waves and changing weather. They often look like spilled paint, pea soup, green streaks, surface scum or discolored patches on the water.
People should avoid water that appears suspicious, keep pets away from discolored areas and rinse off after swimming or boating if they may have come into contact with a bloom.
The latest data shows Cayuga and Otisco lakes had confirmed HAB activity after the July 4 weekend, but the reports were limited in extent as of the latest observations.
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