Harmful algal blooms are being confirmed across several Finger Lakes and Central New York waterways as summer conditions intensify, with dozens of reports recorded since late July and fresh blooms appearing this week on Canandaigua, Cayuga, Owasco and Keuka lakes.
The latest state HAB dataset shows 62 confirmed reports between July 24 and Aug. 4 across Ontario, Cayuga, Yates, Schuyler, Steuben, Cortland and Onondaga counties. The activity provides broader context for Canandaigua’s decision Friday to close its public beach and dog beach after blue-green algae was found in the water.
Canandaigua Lake has accounted for 11 confirmed reports in the dataset, including two on Aug. 4 and another Aug. 1.
The Aug. 4 observations were reported by the Canandaigua Lake Watershed Association and classified as small localized blooms. Earlier reports on the lake have included both small and large localized blooms.
City officials said Friday that HAB conditions can shift rapidly with wind and water movement. The Canandaigua beaches were closed as a precaution, with officials hoping to test the water Saturday morning and reopen if conditions allow.
Cayuga and Owasco lakes also seeing repeated blooms
Cayuga Lake had the largest number of confirmed reports in the dataset, with 14 observations between July 24 and Aug. 4.
Five Cayuga Lake blooms were reported Aug. 4 alone, with observations submitted by the Community Science Institute. Three were classified as large localized blooms and two as small localized blooms.
Several additional large localized blooms were documented July 31.
Owasco Lake had 13 confirmed reports when a capitalization variation in the dataset is included.
Two new Owasco reports were logged Aug. 4, both classified as small localized blooms. The Owasco Watershed Lake Association reported one, while another was reported by a member of the public.
The recent activity comes as Auburn has already activated its powdered activated carbon treatment system to address microcystin, the toxin associated with some harmful algal blooms.
City Manager Jennifer Haines told the Auburn City Council Thursday that treatment began Aug. 3 and the city had submitted its first raw and finished water samples for laboratory testing Aug. 6.
Keuka Lake reports remain widespread
Keuka Lake also continues to see significant HAB activity.
The dataset includes 12 confirmed reports there since July 24, with three reported Aug. 4.
Two of the Aug. 4 observations were classified as large localized blooms, while one was classified as small localized.
Reports have come from both the Keuka Lake Association and members of the public.
Smaller lakes also affected
HAB activity is not limited to the region’s largest lakes.
Waneta Lake had four confirmed reports split between Schuyler and Steuben counties. Two large localized blooms were reported Aug. 4 in Schuyler County, while another large localized bloom was reported Aug. 3 from the Steuben County side.
Cayuta Lake and Lamoka Lake each had a small localized confirmed bloom reported Aug. 4.
Tully Lake in Onondaga County had a large localized bloom reported Aug. 4.
Earlier reports also included two confirmed blooms on Otisco Lake, two on Song Lake and one at Jamesville Reservoir.
Most recent reports clustered on Aug. 4
The dataset shows a noticeable spike in reports Aug. 4, when 15 confirmed blooms were recorded across the region.
Those observations included Cayuga, Owasco, Canandaigua, Keuka, Waneta, Cayuta, Lamoka and Tully lakes.
Not every report represents a lakewide bloom. The state classifications distinguish between small and large localized blooms, meaning conditions can vary significantly from one shoreline or section of a lake to another.
That variability is one reason beach managers and public health officials make decisions based on conditions at specific swimming areas rather than the status of an entire lake.
For Canandaigua, that means the presence of HABs elsewhere on the lake does not necessarily determine whether the city beach can reopen Saturday. Officials said the decision will depend on what they see at the beach and the results of testing if conditions appear clear enough to sample.
The broader regional picture, however, shows HAB season firmly underway across the Finger Lakes, with repeated confirmed blooms now being documented on several of the region’s most heavily used recreational and drinking-water lakes.
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