Harmful Algal Blooms

Harmful algal blooms, or HABs, occur when colonies of algae—simple plants that live in the sea and freshwater—grow out of control while producing toxic or harmful effects on people, fish, shellfish, marine mammals, and birds. The human illnesses caused by HABs, though rare, can be debilitating or even fatal. HABs have been reported in every U.S. coastal state, and their occurrence may be on the rise. HABs are a national concern because they affect not only the health of people and marine ecosystems, but also the 'health' of local and regional economies.

NOAA Forecast for Red Tide in Florida

NEWS/INFOGRAPHIC

Clam diggers along the Washington state coast. So far this year, the presence of harmful algal bloom toxin in Washington state water's has resulted in fishery closures, which can have tremendous economic and ecological effects. In May, the razor clam fishery closed resulting in an estimated $9.2 million in lost income. The state's commercial crab fishery, worth roughly $84 million annually, has also been affected.

West Coast Harmful Algal Bloom Update

NEWS

What is a Harmful Algal Bloom?

OCEAN FACT/VIDEO

NOAA HAB Forecast Bulletins

NOAA HAB forecasts alert coastal managers to blooms before they cause serious damage. Short-term forecasts identify which blooms are potentially harmful, where they are, how big they are, and where they're likely headed. Longer-term, seasonal forecasts predict the severity of HABs for the bloom season in a particular region.

HAB Research

Harmful algal blooms occur naturally, but human activities that disturb ecosystems seem to play a role in the increased occurrence of some blooms. NOAA is authorized by the Harmful Algal Bloom and Hypoxia Research and Control Act to help communities counter this increasing threat with research.

Phytoplankton Monitoring Network

The Phytoplankton Monitoring Network is made up of volunteers who monitor for marine phytoplankton and HABs in cooperation with professional scientists. This effort builds a more informed public while expanding the reach and resolution of HAB monitoring.

NOAA Ecoforecasting Services

An ecological forecast predicts changes in ecosystems and ecosystem components in response to an environmental driver such as climate variability, extreme weather conditions, pollution, or habitat change. It also provides information about how people, economies, and communities may be affected.