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Nationwide Human Health, Coastal Communities and Fisheries Are Threatened By Impacts Of Harmful Algal Blooms

Red tideFebruary 22, 2001 — NOAA and the National Science and Technology Council released the "National Assessment of Harmful Algal Blooms in U.S. Waters" that concludes that the impacts of harmful algal blooms are increasing nationwide.

The assessment, requested by Congress in the Harmful Algal Bloom and Hypoxia Research and Control Act of 1998 (P.L. 105-383), compiles research and management expertise on the causes and consequences of Harmful Algal Blooms and presents recommendations for addressing their impacts nationwide. The study was a multi-disciplinary effort that included input from states, Indian tribes, industry and other coastal stakeholders.

"Harmful algal blooms are a serious threat to coastal communities that rely upon fish and shellfish," said Acting Under Secretary of Commerce for Oceans and Atmosphere, Scott Gudes. "The toxins found in harmful algal blooms can contaminate shellfish, which can cause severe illness or death when eaten. Just last summer, algal blooms are suspected of sending nine people to the hospital with paralytic shellfish poisoning in Washington state."

Harmful algal bloom events regularly threaten human health and marine mammals, contaminate local fish and shellfish, and depress coastal tourist and recreational industries. They can produce toxins and create large dense "blooms" of cells, such as the Florida red tide. Others can threaten human health even when they are not visible in the water, such as Pfiesteria piscicida, the organism that has been associated with fish kills and potential human health effects in Maryland and North Carolina waters.

According to the study, harmful algal blooms appear to be increasing nationwide. There are more toxic HAB species, more HAB events, and more areas and fisheries affected than 25 years ago. This, in turn, means higher economic loses to coastal communities. A recent study conducted by the Woods Hole Oceanographic Institution estimated that the average annual impact of HABs nationwide was $49 million, but individual events can cost that much. Outbreaks of Pfiesteria in the summer of 1997 caused the communities and industries of Maryland $43 million in loses.

Natural events, as well as human activities, appear to contribute to this increase. Storm runoff and the flow of coastal currents have helped HABs to spread along the New England coast and the coast of Florida. Excess nutrients in agriculture runoff have been linked to the growth of Pfiesteria and other HABs.

Management options are limited. For now, the focus remains on minimizing the impacts of HAB events. HAB impacts can be minimized through monitoring programs that regularly sample shellfish to detect HAB toxins—human illness and death from shellfish poisoning has been reduced through such efforts. In addition, monitoring coastal waters for the presence of HAB cells may provide coastal regions with an early warning of HAB events. Recent technological advances have increased detection of algal blooms, from satellite remote sensing that can be used to track blooms offshore, to molecular probes that can detect individual HAB cells in seawater or minute amounts of HAB toxins in blood samples.

It may be possible to prevent or control some HABs. The type of HABs that are stimulated by nutrient enrichment of coastal waters may be reduced by controlling nutrient inputs. However, other HABs appear to occur naturally and cannot be prevented. Scientists believe that a potential approach to controlling HABs by physical means, such as applying clay to the HAB, may cause the toxic cells and HAB specific viruses to sink. However, more research is needed to determine the effectiveness and environmental impacts of these methods.

NOAA and other federal agencies are working with states, tribes, industry, and academic researchers through the multi-agency Ecology and Oceanography of Harmful Algal Blooms research program and the Monitoring and Event Response for Harmful Algal Program to research and develop innovative and cost-effective approaches to minimize, control, and prevent HAB impacts in US waters.

Relevant Web Sites
Read the report online: National Assessment of Harmful Algal Blooms in U.S. Waters
This is a pdf file. You'll need Adobe Acrobat Reader to view it.

NOAA's National Ocean Service

Harmful Algal Bloom and Hypoxia Research and Control Act

NOAA's Harmful Algal Bloom Forecast Project

Hypoxia in the Gulf of Mexico

NOAA's Center for Coastal Environmental Health and Biomolecular Research

Woods Hole Oceanographic Institution

Media Contact:
Connie Barclay, NOAA's National Ocean Service, (301) 713-3066