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Harmful Algal Blooms: What You Need to Know


Speakers from the NYS Department of Environmental Conservation (DEC), the NYS Department of Health (DOH), Cary Institute, and Riverkeeper discuss harmful algal blooms, with a special focus on blooms in flowing waters like the Hudson River.

Last summer, Cary researchers encountered an unprecedented harmful algal bloom in the Hudson River while conducting research on the river's food web. It was the largest bloom observed during nearly 40 years of Cary’s long-term monitoring. The bloom was identified as Microcystis, a type of cyanobacteria that can produce toxins harmful to people, pets, and wildlife. Cary scientists are working with Riverkeeper to develop new monitoring methods and improve our understanding of how to predict and manage future blooms.

Presenters provide an overview of harmful algal blooms, including what they look like in flowing waterways, the potential risks posed by toxin-producing blooms, and current research underway to improve their detection and management. Participants will also learn how to report a bloom in any body of water and ways to support healthy aquatic ecosystems.

Speakers

Brian Duffy, Section Chief of the Monitoring and Assessment Section, Division of Water, NYS DEC
Gena Gallinger, Director of Outreach and Education, NYS DOH
Chris Solomon, Aquatic Ecologist, Cary Institute of Ecosystem Studies
Dan Shapley, Senior Director of Advocacy, Policy and Planning, Riverkeeper

Resources

Monitoring, identifying, and reporting HABs

Identifying and reporting HABs

Report a HAB using the Suspicious Algal Bloom Report Form or via email  HABsInfo@dec.ny.gov.

HABs Reporting Guide (pdf)
NYSDEC: How to identify a suspicious bloom and how to report it.

Reports

Lower Hudson River Harmful Algal Bloom Monitoring 2025
Preliminary results of the survey of the bloom between the towns of Hudson and Newburgh conducted by NYSDEC and Stony Brook University.

Harmful Algal Blooms in the Hudson River (pdf)
Riverkeeper clean water advocacy report on HABs.

General information

Harmful Algal Blooms (HABs)
NYSDEC: Helpful resources on how to identify to stay safe around HABs. Also includes research and mitigation strategies by NYS.

NY Harmful Algal Blooms System (NYHABS)
Interactive map of reported sightings. 

Water Quality Portal
Riverkeeper: Map of monitoring data including bacteria, algae, and potential pollution sources.

harmful algal bloom (HAB) graphic
Videos

DEC Harmful Algal Bloom (HAB) Identification Tips and Tricks [video]

 

Know It, Avoid It, Report It: Harmful Algal Blooms in New York State Webinar 

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