Community Science Institute

After nearly two months without any new reports, CSI confirmed the second Harmful Algal Bloom (HAB) report of the 2026 season on Cayuga Lake yesterday. This latest bloom was observed in the Hibiscus Harbor area (Union Springs), about four miles south of that first report submitted on 4/23/26.

The volunteer who reported the bloom has been monitoring HABs for eight seasons and described the water as clear aside from an "oily green HAB." They also noted that the bloom appeared in a protected cove that tends to experience HABs every year and where blooms can linger for extended periods.

While HAB reports have been relatively quiet so far this season, this sighting is a good reminder that blooms can develop throughout the summer, especially in sheltered areas of the lake.

If you spot suspicious-looking water on Cayuga Lake, anyone can submit a HAB report using CSI's online reporting form: https://arcg.is/08nfyP1

A huge thank you to our volunteer HABs Harriers and Carriers as well as community members who help keep an eye on the lake and contribute to our understanding of HAB activity throughout the season!

2026 Cayuga Lake HAB Report Form This form is to be used by anyone who observes a suspected harmful algal bloom during the monitoring season (June 1 - October 31) on Cayuga Lake. Please fill the form out as completely as possible. If you experience any issues with the form, please contact the HABs Monitoring Program Coordinator, Al...

We’re excited to share a big thank you to one of our newest 2026–2027 Business Members, Kristian Piscitelli - KMP Homes!

After an initial donation at the Stream Stewards level, KMP Homes has gone a step further by pledging an additional 5% commission from future home sales to support both the Cayuga Lake Watershed Network and the Community Science Institute.

At each closing, 5% of KMP Homes’ gross real estate commission will be split between these two 501(c)(3) nonprofits—helping advance clean water, watershed protection, and community-based science in the Cayuga Lake region.

The impact of this commitment is outlined in the graphic below.

Protecting lakefront property values starts with protecting our lakes.

I am proud to announce the Lake Legacy Initiative whereby every lakefront home sold by KMP Homes helps protect Cayuga Lake.

At closing, 5% of KMP Homes' gross real estate commission gets split between the Cayuga Lake Watershed Network and the Community Science Institute. Both organizations are 501(c)3 non-profits. The funding impact is outlined in the graphic below.

Further, to learn more about how your day-to-day at-home habits and practices impact your watershed, explore the Lake Friendly Living program at https://www.cayugalake.org/lake-friendly-living/ and sign up to Take the Pledge.

It is important to note that most, if not all, of the Finger Lakes' have adopted the same Lake Friendly Living program and it has become a regional program of lake stewardship.

Thank you to all of the hard work of CLWN and CSI to help keep Cayuga Lake healthy and the public educated!

Have you seen something like this floating on the water lately?

While it’s often mistaken for a harmful algal bloom (HAB), this is actually tree pollen! We're currently in peak pollen season, and trees across the region are releasing large amounts of pollen that can accumulate on the water's surface and resemble a bloom.

So how can you tell the difference?

🌳 Color: Tree pollen is typically yellow. HABs are most often shades of green, blue-green, turquoise, or aqua. While pollen and HABs can sometimes occur in the same area at the same time, a bright yellow slick is usually pollen.

📅 Time of year: May and June are prime pollen season, making pollen the most likely explanation for yellow surface accumulations. That said, HABs can occur in spring and early summer as well. In fact, Cayuga Lake's first confirmed HAB of 2026 was reported on April 23.

If you see something that might be a HAB on Cayuga Lake—even if you're not completely sure—we encourage you to report it. Community observations help us track conditions around the lake and investigate potential blooms.

Thank you, Tompkins Weekly for continuing to assist us in sharing information about Cayuga Lake’s harmful algal blooms.

If you think you’ve spotted a HAB, please submit a report at this link: https://arcg.is/08nfyP1

Harmful algal blooms are hitting Cayuga Lake earlier and lasting longer, prompting health officials to warn swimmers and pet owners to watch for toxic green scum this summer.

📰: https://www.tompkinsweekly.com/news/harmful-algal-blooms-arriving-earlier-lasting-longer-officials-urge-vigilance-as-hab-season-returns-to-cayuga-lake-860b8f5d

📸: Left and center photos submitted. Right photo by Jaime Cone Hughes