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Harmful Algal Blooms threaten human and ecosystem health, and disrupt aquaculture and wild fisheries, tourism, and other resources in marine and freshwater systems.

What are Harmful Algal Blooms (HABs)?

Marine and fresh waters teem with life, much of it microscopic and most of it beneficial and harmless. There are, however, some species of algae and cyanobacteria that cause harm, either through the production of potent toxins or through the accumulated biomass during their “blooms”. Impacts include human and wildlife illness and mortality, ecosystem disruption, and economic losses to coastal communities.

HAB Species

Learn about different toxic or harmful algal species, and the poisoning syndromes they cause


See where harmful algae are distributed in the U.S. and around the world


Discover how harmful algal blooms impact human health and coastal economies, wildlife, ecosystems, and more


Learn about the national and international research programs focused on understanding, managing, and preventing harmful algal blooms


Major programmatic and informational resources regarding harmful algal blooms, as well as fact sheets and hotlines


Programs and activities focused on prediction, control, mitigation, and HAB event response

News and Announcements

2024 NOFO Announced

August 24, 2023

NOAA’s National Centers for Coastal and Ocean Science Competitive Research Program (NCCOS/CRP) is pleased to announce a Fiscal Year 2024 Notice of Funding Opportunity (NOFO) for Social, Cultural, and Economic Assessment of Harmful Algal Blooms.   For this opportunity, NCCOS/CRP is soliciting proposals that assess the social, cultural and economic impacts of HAB events. Research…

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Alexandrium catenella forecast FY2023 released!

May 18, 2023

NOAA NCCOS is pleased to announce the release of our FY2023 season Alexandrium catenella nowcast/forecast for the Gulf of Maine. ** Note: if you are using google chrome, make sure that you clear the browser cache each week to view the latest model results. All other browsers should pick up the update automatically.

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Taxonomic Identification of Harmful Algae in U.S. Marine Waters Course

February 10, 2023

Effective monitoring and management of harmful algal blooms (HABs) relies on accurate and timely identification of the species involved. The classic method of detection is microscopic examination for HA species based on morphological characteristics. The rapidly expanding harmful algae taxonomy field, retirement of many ‘classical’ taxonomists, lack of dedicated U. S. harmful algae taxonomic and…

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ICHA 2023 in Hiroshima, Japan

December 9, 2022

The 20th International Conference on Harmful Algae (ICHA) will be held November 5-10, 2023, in Hiroshima, Japan.  Please visit the conference website HERE.

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Upcoming Conferences and Events

November 29, 2022

Interested in attending upcoming conferences, meetings, workshops, or other events related to HAB science? A timeline of  events of interest to the HAB community is available on the US HAB website, and updated periodically.  Please click  HERE to view the timeline & current listings, which are updated periodically. If you wish to post a meeting or event, please contact 

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Educational and job opportunities in HAB Science!

November 29, 2022

HABs-related job openings, graduate student positions, and other opportunities are available HERE. Please check back frequently as listings are updated. If you wish to post a position or opportunity here, please contact

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Proceedings of the the Workshop on the Socio-economic Effects of Harmful Algal Blooms in the United States

March 18, 2022

The proceedings document describing the Workshop on the Socio-economic Effects of Harmful Algal Blooms in the United States is now available here. The report documents the proceedings of a 2020 workshop convened by NOAA NCCOS and the U.S. National Office for HABs, and presents recommendations to advance an assessment framework and a national research agenda that will lead to comprehensive evaluations of the social and economic effects of HABs in the fresh (primarily the Great Lakes) and marine waters of the United States.

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HARMFUL ALGAE NEWS No. 72 now available

February 22, 2022

HARMFUL ALGAE NEWS No. 72 now on online! Be sure to check it out HERE

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11th U.S. Symposium on Harmful Algae

November 23, 2021

Thank you for attending the 11th U.S. Symposium on Harmful Algae! The final program and agenda is available HERE.  Additional program information will be posted when available.

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19th ICHA – Abstract book available!

October 4, 2021

Thanks to the organizers of this virtual event! The abstracts are available HERE.  Conference proceedings will be posted when available.

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