Harmful Algal Blooms

Report Algal Blooms: Algae Bloom Sighting Report or call (866) 633-4686.

To learn more about Harmful Algal Blooms (HABs) visit the Phytoplankton Monitoring Program. We also have a basic factsheet on harmful algae in the Chesapeake and Coastal Bays. To learn about the state-wide harmful algal bloom surveillance program, check out this factsheet on Harmful Algal Bloom Management.

Any recent HAB stories will appear below the map, or find archived HAB stories in our searchable database.

Show Legend

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Relative algal abundance:
	Site Sampled
Algae were sampled, no harmful species identified
	Algae Bloom
High abundance of algae that are not known to produce any toxins, but impact bay health. No human health advisory.
	Potentially Harmful Algae
A species of concern was identified below bloom thresholds. No human health advisory.
	Harmful Algae Bloom
Public should be aware of blooms in the vicinity. Blooms have the potential to produce toxins that are harmful to humans, pets, or fish and/or have ecosystem impacts.
Algae are a natural part of the Bay ecosystem; however, some algae may be harmful when they bloom in unnaturally high abundance or they may produce a toxin that can impact people, animals and/or bay life.  Toxin testing is initiated when cell densities exceed set thresholds. Visit DNR's Harmful Algal Bloom page for more information.

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No recent HAB stories to report.

View the Archived HAB Map (qualitative data)
Note: Archived HAB Map data from samples prior to 2015 should not be used for analytical purposes
as these were qualitative assessments based on live cell counts.

If you would like to request algae data, please email us.