Harmful Algal Blooms (HABs)

Primary funding for the Harmful Algal Bloom Response Plan is provided by donations. Your support is needed!

The Concern:

Harmful algal blooms (HABs) in freshwater (lakes, ponds, rivers, and streams) generally consist of visible patches of cyanobacteria, also called blue-green algae. Cyanobacteria are naturally present in low numbers in most aquatic (freshwater and/or marine) systems. Under certain conditions, including adequate nutrient (e.g., phosphorus) availability, warm temperatures, and calm winds, cyanobacteria may multiply rapidly and form blooms that are visible on the surface of the affected waterbody. Several types of cyanobacteria can produce toxins and other harmful compounds that can pose health risks to people and animals through ingestion, skin contact, or inhalation.

To learn more about identifying HABS and what to do if you encounter HABs, click here.

Our Program:

“So, how do we prevent blooms? The only thing we can do is [reduce] nutrients. This is why there is a big focus on preventing nutrients from coming into the lake.”  – Dr. Greg Boyer, SUNY ESF

In 2017, a lake-wide HAB turned the entire lake green prompting development of SLA’s Harmful Algal Bloom Response Plan. The plan focuses on programs to help prevent nutrient-loading in the lake such as:

  • Watershed Improvement Projects
  • Research & Monitoring
  • Education & Community Outreach

You can read more detail about these projects in our 2023 Special Report.

Skaneateles Lake participates in the NYS Department of Environmental Conservation HAB Surveillance Program. Over 30 residents have been trained in identifying and sampling HABs, are monitoring the lake weekly and coordinating response to reports of suspicious blooms from the public. SLA documents the occurrence of HABs, reports them to the NYSDEC, and informs the community of HABs locations on our website and social media channels with strategies to avoid them.

Recent HABs on Skaneateles

Staying Safe Around HABs

Be prepared

Before you go in the water, check which waterbodies currently have HABS by using this NYSDEC Notifications page.

Know it

Because it is hard to tell a HAB from non-harmful algal blooms, it is best to avoid swimming, boating, otherwise recreating in, or drinking water with a bloom.

Avoid it

  • People, pets, and livestock should avoid contact with any floating mats, scums, or discolored water. Colors can include shades of green, blue-green, yellow, brown or red.
  • Never drink, prepare food, cook, or make ice with untreated surface water, whether or not algae blooms are present. In addition to toxins, untreated surface water may contain bacteria, parasites, or viruses that could cause illness if consumed.
  • People not on public water supplies should not drink surface water during an algal bloom, even if it is treated, because in-home treatments such as boiling, disinfecting water with chlorine or ultraviolet (UV), and water filtration units do not protect people from HABs toxins.

Report it


The information above comes from the NYSDEC website.