Harmful Algal Blooms

Harmful Algal Blooms, or HABs, are an increasing concern in freshwaters around the world.  New York lakes are no exception. Certain types of blue-green algae, also known as cyanobacteria, produce toxins that can harm other organisms, including humans. Not all algae is blue green, and not all of the blue green species that are capable of producing toxins do so all of the time. Scientists are trying to determine what makes these organisms produce toxins.

If you suspect a cyanobacteria bloom is occurring on your lake, avoid contact with it.


Harmful Algal Bloom Resources

U.S. EPA Harmful Algal Bloom Web Page


NYS DEC Harmful Algal Bloom Web Page http://www.dec.ny.gov/chemical/77118.html
NYS DOH Harmful Algal Bloom Web Page https://www.health.ny.gov/environmental/water/drinking/bluegreenalgae/
NALMS Inland HABs Program https://www.nalms.org/inlandhabs/

Harmful Algal Blooms in New York

NYSFOLA is working closely with the New York State Department of Environmental Conservation, the SUNY College of Environmental Science and Forestry, Upstate Freshwater Institute, and lake associations around the state to identify, sample, and analyze algal bloom samples.

Much of this work is completed by volunteers participating in the Citizens Statewide Lake Assessment Program (CSLAP), but the state is also accepting reports from lakes that are not in the program.  

Where Are Blooms Occurring in NY?

The Harmful Algal Bloom notification page is updated every Friday from approximately mid-June through mid-October.  Click here to go to the NY HAB notification page.

How to Report a Bloom in NY

  • NYS DEC’s HABs Reporting Guide offers guidance on blooms and bloom reporting.  
  • If you suspect that you have seen a HAB, please report the HAB to DEC. Fill out and submit a Suspicious Algal Bloom Report Form. If possible, attach digital photos (close-up and landscape to show extent and location) of the suspected HAB in the web form. Email HABsInfo@dec.ny.gov if you are not able to complete the form.
  • Please report any health symptoms to NYS Health Department at harmfulalgae@health.ny.gov and your local health department.

What Does a Harmful Algal Bloom Look Like?

The most common types of cyanobacteria blooms seen in New York, will look like green dots or streaks in the water or accumulations of “paint” or “pea soup” along the shoreline.  In severe blooms, the entire lake may have a pea green appearance.

NYS DEC Algae Photo Gallery

NYS DEC Harmful Algal Bloom (HAB) Identification:  Tips and Tricks Video

A few blooms in New York have been caused by the cyanobacteria genus Planktothrix.  This may give the lake a purple or red appearance.

Is My Public Water Supply Safe?

The New York State Department of Health works closely with public water purveyors to ensure that your drinking water is safe  https://www.health.ny.gov/publications/6632.pdf.

Is My Private Water Supply Safe?

The New York State Department of Health has produced guidance regarding the risks of piping surface water into your home or camp https://www.health.ny.gov/publications/6629.pdf.\

What Can Be Done to Control Harmful Algal Blooms?  

Reducting nutrient input to lakes is critical to HABs prevention, but there are emerging technologies for reducing blooms when they occur.  

Other Resources:

Your Pets and HABs

Dogs are particularly susceptible to the impacts of harmful algal blooms when they lap up lake water or lick algae covered fur.  Sea Grant NY has produced a very helpful brochure with information regarding dogs and HABs:


US EPA has produced a YouTube Video to remind people to keep their pets out of blue-green algae blooms. For more information about protecting your pet, go to: http://www2.epa.gov/nutrientpollution/protect-your-pooch. The Centers for Disease Control (CDC) has also published this flyer, that you can copy and share with your lake association members: