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Worst New England Harmful Algal Bloom in 30 Years

Alexandrium under the microscope. Photo courtesy of the Woods Hole Oceanographic Institution
Alexandrium under the microscope. Photo courtesy of the Woods Hole Oceanographic Institution

In 2005, the most severe bloom since 1972 of the microscopic alga, Alexandrium fundyense, spread from Maine to Massachusetts, resulting in extensive commercial and recreational shellfish harvesting closures to protect humans from paralytic shellfish poisoning (PSP). Alexandrium blooms are one of several algal bloom types often called red tides, but more correctly referred to as Harmful Algal Blooms (HABs). Such blooms occur periodically in the Gulf of Maine but rarely at the density and geographic extent witnessed during this event. The abnormally large bloom was possibly due to elevated rainfall and snowmelt in the Spring followed by two unusually late Nor'easters in May. The strong winds may have pushed the Alexandrium down the coast, while increased runoff likely fueled the outbreak by creating ideal conditions for growth.

Alexandrium produces potent neurotoxins that can accumulate in filter-feeding shellfish. Consumption of toxin-contaminated shellfish by humans can result in severe illness and death due to PSP Syndrome. States are responsible for rigorous shellfish monitoring programs in coastal waters to prevent outbreaks of PSP. State shellfish closures along the New England coast began as early as mid-May, disrupting the busiest period of the tourist season. In Massachusetts alone, economic losses due to shellfish closures were estimated at $15 million. Areas were closed that had never been closed in previous outbreaks. A temporary closure of federal waters was declared on June 14, 2005, based on the transport of toxic cells offshore (click here for chart of temporary closure area).

On September 9, 2005, NOAA Fisheries Service partially re-opened the temporarily closed Federal waters for harvesting of some bivalve mollusks (click here for a chart of the re-opened area). States had reopened many areas to shellfish harvesting by Autumn 2005, but some areas remain closed almost a year after the bloom began due to sustained shellfish toxicity. It is important to check state and federal websites for the latest information on shellfish closures.

NOAA officials emphasize that commercially available seafood is safe to eat, and that residents and visitors to the region should follow the guidelines offered by local officials in Massachusetts, New Hampshire, and Maine.

For more information on this event, consult Woods Hole Oceanographic Institution's Update on the Spring 2005 outbreak.

NOAA Funded Research Provides Knowledge Base to Aid Response

CSCOR's Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) and Monitoring and Event Response to Harmful Algal Blooms (MERHAB) research on Alexandrium in the Gulf of Maine — encompassing $11 million from 1998 through 2007 — has greatly enhanced response capabilities in the region. New molecular methods for rapidly detecting and mapping Alexandrium were being used to track the bloom in almost real time. These data, combined with oceanographic and meteorological data from ships and moorings, were used in recently developed, coupled biological and physical models to forecast the spread of the red tide and to understand the factors leading to this unusual event. This integration of ocean observing system data with models during this harmful algal bloom event is an example of the predictive, regional, ecosystem-based research being conducted at NOAA to assist managers and the public in understanding and responding to coastal ocean issues.

Response to Massive Harmful Algal Bloom in New England

Collection of water samples from research ship. Photo courtesy of the Woods Hole Oceanographic Institution
Collection of water samples from research ship. Photo courtesy of the Woods Hole Oceanographic Institution

The 2005 New England Harmful Algal Bloom was first detected offshore by WHOI researchers on a research cruise in the Gulf of Maine and Massachusetts Bay as part of a project for the NSF/NIEHS-supported Woods Hole Center for Oceans and Human Health (COHH) . NOAA responded to the New England Harmful Algal Bloom by providing emergency funding to pay for new and expanded sampling of the toxic algae in Massachusetts Bay. This emergency funding through NOAA's Ocean Service National Centers for Coastal Ocean Science/ Center for Sponsored Coastal Ocean Research's (CSCOR) Harmful Algal Bloom Event Response Program allows monitoring of the extent and movement of the bloom in order to provide managers with early warnings of shellfish toxicity to protect public health in the region. Initial funding of $16,300 was awarded on May 23, 2005 for a series of cruises to assess the extent of the bloom in Massachusetts coastal waters. Expansion of shellfish closures to Buzzards Bay, Nantucket Island, and Martha's Vineyard raised the concern that Alexandrium could move into southern New England and New York waters, resulting in additional shellfish closures. Supplemental funding amounts of $2,300 and $12,000 were approved on May 27, 2005 and June 8, 2005, respectively, to support cruises that continue to assess the spread of the bloom. After the declaration of the temporary closure in federal waters on June 14, 2005 some monitoring cruises were extended into federal waters. Information about Alexandrium abundance is of great value to state coastal managers because it allows them to focus their sampling efforts on new areas and decrease sampling efforts in areas that were already closed and which are surrounded by waters with very high Alexandrium concentrations. Information about cell densities allows managers to focus toxin sampling on areas where shellfish openings will be most likely to be possible.

Organizations involved in the emergency response to this HAB event include the Woods Hole Oceanographic Institution (WHOI), Massachusetts Division of Marine Fisheries, Massachusetts Water Resources Authority (MWRA), University of Massachusetts - Dartmouth Center for Coastal Studies in Provincetown, and the Cooperative Institute for Climate and Ocean Research. At times, four research vessels supported and staffed by WHOI and these groups have been in the water simultaneously sampling this bloom. Ancillary data from moorings was provided by the Gulf of Maine Ocean Observing System and the U.S. Geological Survey's Woods Hole instrumented mooring near the MWRA outfall.

NOAA officials emphasize that commercially available seafood is safe to eat, and that residents and visitors to the region should follow the guidelines offered by local officials.

Scientist analyzing samples in the field. Photo courtesy of the Woods Hole Oceanographic Institution
Scientist analyzing samples in the field. Photo courtesy of the Woods Hole Oceanographic Institution

NOAA Funds Follow-Up Research

NOAA awarded an additional $540,000 to WHOI to sustain monitoring throughout the bloom period and to support post-bloom research (see press release) to enhance prediction and response for 2006 and future years. The post-bloom research addressed two main objectives geared toward improving future mitigation efforts:

  • The comprehensive dataset will be used to ìhindcastî causative factors which will improve bloom forecasts. Data collected during the 2005 event will ultimately be incorporated into integrative, predictive models that were developed through NOAA-supported research over the last decade.

  • The high abundance and broad extent of the 2005 event suggested potential for newly deposited cysts (or seeds) on the seafloor in areas where cyst beds previously did not exist. The new cyst beds were mapped, and new areas will be monitored to evaluate the potential southward expansion of these events in 2006 and subsequent years.

For Up-To-Date Information on Shellfish Closures, Consult the Following Web Sites:

Information About NOS/NCCOS/CSCOR ECOHAB, MERHAB, and Event Response

Recently Funded NOAA Studies on Harmful Algal Blooms in the Gulf of Maine

Pictures of Alexandrium fundyense

Information About Alexandrium and its Toxins

Press Releases About this Event

Coverage in the Press

General Information About Harmful Algal Blooms

Key Legislative and Scientific Drivers Guiding NOAA Response to HABs