The Issue:

Cyanobacteria, commonly referred to as blue green algae or harmful algae blooms (HABs), occur in freshwater lakes, ponds, and surface waters worldwide.  A combination of factors allow the bacteria to grow into blooms that can be harmful to human and animal health and degrade our water quality:

  • Phosphorus and nitrogen inputs (nutrients) from the surrounding watershed fuel algal growth.
  • Calm, sunny weather creates ideal cyanobacteria growing conditions.
  • Dreissenid mussels (zebra and quagga mussels) have been altering our lake ecosystems and don’t filter cyanobacteria out of the water.
  • Nutrients originate in the watershed and have many sources. Reducing nutrients from the watershed is the only strategy we have to help limit our impact.

What to look for:

Use visual cues to identify harmful algae blooms. They can appear like pea soup, spilled paint, globs, or surface streaks. The color is typically green, blue-green, or yellow, but can also be brown, red or purple. Visit the DEC photo gallery to learn more about identifying blooms.

The Risk:

Some HABs are capable of producing toxins, called cyanotoxins, which can pose health risks to humans and animals. Exposure to cyanobacteria and their toxins can occur by contact (touching, swallowing, and inhaling), during water recreation, drinking water, and household use. Pets (especially dogs) are very susceptible to the toxins associated with blooms as they are likely to drink surface waters when swimming and may also be exposed when grooming themselves after a swim in the lake.

It’s very important to remember: If you see bloom conditions, avoid it! Blooms can appear quickly in the lake when the conditions are just right. Please use your visual indicators before recreating in the water – stay safe and avoid it. Be especially careful to scan the waterfront before pets and children enter the water!

Please check out these resources to learn more about HABs and our Health:

Know it.

  • HABs may look like green parallel streaks on the water surface, or have a spilled paint or pea soup appearance. Check out the DEC webpage to learn how to ID HABs.

Avoid it.

Report it.

  • If you think that a bloom may be harmful and is present on Canandaigua Lake, take a photo and report it to Please include the location where the photo was taken. Public reports assist in the ongoing monitoring activities on the lake.

Additional Resources:

hab brochure pic

HAB Brochure Canandaigua Lake

dogs and habs pic

 Dogs and HABs Fact Sheet


DEC HAB Reporting Guide




The Canandaigua Lake Watershed Association and the Canandaigua Lake Watershed Council co-hosted a community discussion on HAB events on Canandaigua Lake.   A panel of experts each presented a powerpoint, followed by a question and answer session. The experts discussed the science behind HABs and the sequence of events on Canandaigua Lake. Video and presentations are below.

Kevin Olvany – Blue Green Algae presentation

Scott Kishbaugh – Canandaigua Presentation

Dr. Greg Boyer – Introduction to HABs

October 20, 2015 Canandaigua Lake Watershed Association – Blue Green Algae Presentation [HD] from Finger Lakes TV on Vimeo.