Harmful Algal Bloom (HAB) Event Information
Bloom Code 25-3489-B1
Where
Water Body Cayuga Lake
Latitude and Longitude 42.69531, -76.74064
Segment Lakeshore Segment Northwest 1: Sheldrake Point to Deans Cove
County Seneca
Extent Widespread
When
Bloom Reported September 23, 2025 08:42 PM
Bloom Sampled September 23, 2025 08:42 PM
Microscopic Examination September 26, 2025
What
Bloom Genera [1]
Microscopy Present Dominant
Dolichospermum
Microcystis

Bloom Chemistry
Total Chlorophyll a 720.0 ug/L
Total Microcystin and Nodularins (EPA 546) [2] 455.0 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

2025 PRIORITY SITE: Thirsty Owl Wine Company- identified by Seneca County Health Department as a sample-collection site. Volunteer Reports: Looked like mostly south of the zone. Calm, 69 degrees

Weather
Weather
Wind speed
Wind direction
Water Temp
Air Temp