You are here: Home › News & Features › Monitoring Alexandrium Red Tide in New England in 2008


Prediction, Response, and Status of New England Red Tide 2008

Current Status of 2008
New England Red Tide

September 11, 2008

On September 4, the Governor of Massachusetts requested that NOAA NMFS declare a commercial fishery failure, which would make industry eligible for federal disaster assistance under the US Magnuson-Stevens Fishery Conservation and Management Act (State press release). 

On September 2, Maine reduced the area closed to harvesting of mahogany clams.

Click on the state name for up to date information on shellfish closures. Massachusetts, New Hampshire, Maine and New York

For archived updates click here

For a summary of the bloom progression click here

Prediction
On April 24, 2008 NOAA-supported scientists at Woods Hole Oceanographic Institution (WHOI) and North Carolina State University (NCSU) forecasted a larger than normal New England Red Tide, or Alexandrium bloom, in the Gulf of Maine. This year’s bloom could be comparable to the historic event of 2005 that resulted in an estimated direct impact of $18 million to the commercial shellfishing industry in Massachusetts. Alexandrium blooms are one of several algal bloom types often called "red tides," but more correctly referred to as Harmful Algal Blooms (HABs). Alexandrium produces a potent toxin that accumulates in shellfish and can cause illness in humans who eat contaminated shellfish.  States have well-established, rigorous shellfish monitoring programs to protect human health, so consumers are assured that commercially available shellfish are safe for consumption.

The 2008 forecast was based on runs of a biological-physical model, developed with ECOHAB and MERHAB support, using weather scenarios typical of the last few years. A critical component of the model is a map of Alexandrium “resting” cysts on the seafloor, conducted every fall, as an indicator of bloom potential the next spring.  The cysts of Alexandrium act as seeds and germinate every spring when conditions are right.  The numbers of cysts in fall 2007 were 30% higher than before the 2005 bloom. 

For more on the 2008 forecast, see the WHOI press release.

Response

WHOI and NCSU, through the NSF/NIEHS Centers of Oceans and Human Health, will continue with weekly forecasts, based on current weather and oceanographic conditions, to predict Alexandrium abundance and the path of the bloom throughout the bloom season.  This information alerts marine resource managers to the potential magnitude and location of the problem so they can focus monitoring strategies.  The ECOHAB GOMTOX project will be conducting surveys of Alexandrium cell distributions in the water, primarily in the southern Gulf of Maine, including Georges Bank, but also on selected transects in the coastal Gulf of Maine.   Also as part of the GOMTOX project, NOAA Northeast Fisheries Science Center, in conjunction with WHOI, is deploying drifters within the Alexandrium bloom to predict bloom movement and guide sampling.  Two event response awards from NOAA CSCOR for sampling Alexandrium abundance complemented ECOHAB GOMTOX efforts, allowing surveys of the Western Gulf of Maine as well as southern New England waters.  The first response supported sampling transects off of Cape Cod after a significant number of cells were observed at three underway stations around Monomoy Island and Nauset during an ECOHAB GOMTOX cruise.   The second supported surveys in coastal waters of western Maine, New Hampshire, and Massachusetts, as well as areas to the west of Nantucket Shoals towards Rhode Island.  In late July, CSCOR Event Response provided a third award to support investigations of lobster tomalley toxicity by the state managers in Maine and New Hampshire. For more on this response, click here.

The States have responsibility for monitoring PSP-toxins in shellfish and closing beds for harvesting to protect human health.  The State of Maine also deploys bags of mussels on buoys to provide early warning and allow precision opening and closing of shellfish beds.  Updates will be given here as the bloom progresses.

Summary of Bloom Progression

Low levels of Alexandrium were observed in Massachusetts Bay and New Hampshire coastal waters in April, 2008.  By early May, cell counts were higher than normal in the same areas that the models predicted.  By mid-May, elevated numbers of Alexandrium were found in Massachusetts and Cape Cod Bays. Surveys from May 29 to June 4 found Alexandrium in high abundance outside of Cape Cod, in Massachusetts Bay, in western coastal Gulf of Maine, and on the southwest of Georges Bank.  Surveys of Massachusetts and Cape Cod Bays in late June showed that the bloom was ongoing with the high concentrations observed in Cape Cod Bay. An offshore survey in early July showed a decrease in Alexandrium abundance on Georges Bank. By late July Alexandrium had disappeared from Georges Bank and by mid-August Alexandrium abundance in eastern Maine coastal waters was very low. For maps of Alexandrium abundance and more on cruise observations, visit WHOI’s 2008 cruise observation page.

There was a small closure in western Maine on April 29, which was expanded to a much larger area and more species on May 8 and expanded again on May 19 and May 20.  In late June, soft shell clams were removed from the western Maine closure area, and the closure was lifted on mussels for most of Casco Bay. In eastern Maine, some areas were closed for harvesting of mussels, carnivorous snails, and European oysters on May 15, following the typical closure pattern for eastern Maine. Expansions to new areas occurred mid and late June and again in early July, and part of the mahogany clam beds were closed on June 25.  As of July 9, all mahogany clam beds were closed in the state of Maine and in surrounding Federal waters.   Shellfish harvesting was also closed in Canadian waters of the Bay of Fundy due to an Alexandrium bloom there.  On August 1, Maine removed clams from the harvesting closures in eastern Maine and surf/hen clams from closures in areas of western Maine.  On August 7, the size of the closure area for mussels, carnivorous snails, and European oysters was reduced in Eastern Maine. On August 15, the area from Small Point to Mosquito Head in western Maine and the area of Cobscook Bay and some surrounding areas in eastern Maine were opened for harvesting.  A small exception area of the mahogany clam beds was also opened for harvesting on August 15 and the area opened to harvesting was expanded on September 2.

Shellfish beds in New Hampshire Atlantic waters were closed to harvesting on April 29 and in some estuarine waters in early May.  Shellfish beds along the Massachusetts North Shore were closed on May 15, and this closure was expanded on May 21 to cover the area from New Hampshire to Nahant, MA.  A portion of the south shore was closed on May 20. Massachusetts expanded closures to the Boston Harbor area on June 12. In late June, Massachusetts issued a closure for selected species for areas of Monomoy, Nantucket, and Chatham.  In late June, a partial opening was issued for soft shelled clams in Essex Bay and for blue mussels in Pleasant Bay.  On July 3, another partial opening for blue mussels and soft shell clams was issued for areas of Plum Island Sound, Ipswich River, and Annisquam River.  In mid-July, Massachusetts reopened areas of Pleasant Bay and Salt Pond to harvesting of bivalve shellfish. On August 20, some areas from Gloucester to Cohasset were opened to the harvesting of soft-shell clams, razor clams, and blue mussels; however, much of the area remained closed due to bacterial contamination. On September 4, the Governor of Massachusetts requested that NOAA NMFS declare a commercial fishery failure, which would make the industry eligible for federal disaster assistance under the US Magnuson-Stevens Fishery Conservation and Management Act.


On June 20, Massachusetts also restricted vessels registered under Commonwealth law to harvest some species of shellfish from Federal waters adjacent to the state. On July 2, NOAA NMFS closed a block of Federal waters south of Cape Cod and east of Nantucket to the taking of all bivalve mollusks due to the risk of PSP contamination.

In early May, shellfish beds were also closed in the Nauset system in Massachusetts and in some bays of Long Island Sound due to Alexandrium produced saxitoxin, but these were thought to be isolated events that are not linked to the bloom in the Gulf of Maine.  In late June, Massachusetts issued a partial opening for blue mussels in some areas of the Nauset estuarine system, and New York rescinded the closure of approximately 2000 acres in northwest Suffolk County of Long Island.

In early July, three local residents were hospitalized in Maine after harvesting and consuming mussels from an area that had been closed to harvesting.  In Canada, eight people in New Brunswick became ill after eating clams taken from an area of the Bay of Fundy shoreline, which was also under a shellfish harvesting ban. These illnesses highlight the importance of abiding by closures issued by appropriate regulatory authorities.

In late July, high levels of PSP toxins in the hepatopancreas (more commonly called ‘tomalley’) of some lobsters prompted the states of Maine, New Hampshire, and Massachusetts as well as the Food and Drug Administration (FDA) to issue advisory warnings against the consumption of lobster tomalley.  For more information, see the press releases from Maine, New Hampshire, Massachusetts, and the FDA. 

For more on cruise observations, visit WHOI’s 2008 Cruise Observation Page

For information on harvesting closures, see state webpages.

Alexandrium Research and Response

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

Related Links