Harmful Algal Bloom (HAB) Event Information
Bloom Code 25-3458-B1
Where
Water Body Cayuga Lake
Latitude and Longitude 42.94222, -76.73242
Segment Lakeshore Segment Northeast 1: Northern Marshes to Harris Park
County Cayuga
Extent Small Localized (few properties)
When
Bloom Reported July 08, 2025 09:45 AM
Bloom Sampled July 08, 2025 10:00 AM
Microscopic Examination July 09, 2025
What
Bloom Genera [1]
Microscopy Present Dominant
Dolichospermum
Microcystis

Bloom Chemistry
Total Microcystin and Nodularins (EPA 546) [2] 4.57 ug/L
Total Chlorophyll a 4050.0 ug/L
[1] Genera - plural of genus, a category of classification in biology that ranks between the family level and the species level. Because there are many different species of bacteria that are difficult to distinguish, it is more useful to classify bacteria by genus rather than species.
[2] Microcystin
Map of HAB event
Bloom Description

The volunteers report: The morning is cloudy and conditions are 74F and winds from the NW. We had over 1/3 inch rain yesterday and the weather has been in high 80s and over 90 sometimes recently. The water temperature was 77.7F at time of sampling. The bloom is very limited and is modestly accumulating on the northern edge of the dock and shoreline as the current from the north carries it there. The bloom in the priority zone is very limited (the second photo shows the area on the opposite side of the dock where the bloom had accumulated and it’s apparent that there is no accumulation on that side, though the dots of bloom are visible flowing in the current. There is a separate bloom in the same zone to be reported south of the priority zone where the bloom is modest but more apparent.

Weather
Weather Rain within past three days
Wind speed
Wind direction
Water Temp
Air Temp