May 20, 2008

As of this writing, the 2008 bloom of Alexandrium fundyense is proceeding in a manner strikingly similar to that observed at the onset of the 2005 event. In 2005, for example, the first areas to become toxic were in western Maine and New Hampshire, during the first week of May. This year, during that same interval, those areas again became toxic and were closed for shellfish harvesting (see comparison maps). In 2005, the toxicity subsequently spread to the south (Massachusetts) and to eastern Maine in subsequent weeks. This has also occurred in 2008 with toxicity extending further to the east in Maine, as well as into northern Massachusetts and, most recently, to Boston's south shore as of May 20th.

We have conducted cruise operations to sample for Alexandrium cell abundance, and these observations are entirely consistent with the patterns of shellfish toxicity. During our first GOMTOX cruise in 2008, funded by the NOAA NCCOS program called ECOHAB with leverage from the NSF/NIEHS Centers for Oceans and Human Health, a large offshore bloom of Alexandrium fundyense was documented, along with the beginnings of the 2008 coastal bloom of this organism in western Maine. The offshore toxicity is significant, as Georges Bank and Nantucket Shoals are important resources for surfclams, ocean quahogs, and sea scallops, all of which can be affected by PSP toxins. Note that the portion of the scallop eaten in U.S. markets (the adductor muscle) is not affected by PSP toxins.

Smaller-scale vessel surveys have subsequently demonstrated that A. fundyense cells are in moderate abundance in the vicinity of Cape Ann Massachusetts, and have also entered Massachusetts and Cape Cod Bays due to the northeasterly winds that have been prominent over the last several weeks. This distribution is again strikingly similar to Alexandrium abundances mapped out at the onset of the 2005 bloom at the same point in time. Shortly after this recent cruise on May 15-16, 2008, shellfish beds from Hull to Marshfield, Massachusetts were closed, consistent with the observed cell distributions.

Looking ahead, the winds over the next week or two will be critical in determining the extent and magnitude of the toxicity in nearshore shellfish. Sustained winds out of the southwest may stall the southward progression of the bloom and reduce its magnitude, whereas strong northeasterly winds may create high toxicity and spread the problem further, much as occured in 2005 with a major northeaster on May 23. Furthermore, our experience also tells us that the progression of toxicity in Maine is generally from west to east, and as the 2008 bloom season progresses, we expect that the coast of Maine will have more closures in eastern waters over the next month or two.

For the April 24, 2008 WHOI press release, please click here.

Last updated: July 1, 2019