Harmful Algal Bloom (HAB) Event Information
Bloom Code 25-3441-B2
Where
Water Body Cayuga Lake
Latitude and Longitude 42.6657, -76.6989
Segment Lakeshore Segment Southwest 10: Lively Run to Sheldrake Point
County Seneca
Extent Small Localized (few properties)
When
Bloom Reported September 24, 2025 07:00 PM
Bloom Sampled September 24, 2025 07:00 PM
Microscopic Examination September 26, 2025
What
Bloom Genera [1]
Microscopy Present Dominant
Microcystis

Bloom Chemistry
Total Chlorophyll a 58.4 ug/L
Total Microcystin and Nodularins (EPA 546) [2] 36.8 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

2025 PRIORITY SITE, Zone #3441: Sheldrake Point- identified by Seneca County Health Department as a sample-collection site. Volunteer reported: Very hard to pickup in the photos due to lowlight (collecting sample just after sunset), and the bloom didn’t seem very dense. It was apparent in person though.

Weather
Weather
Wind speed
Wind direction
Water Temp
Air Temp