Public warning signs like these will appear in areas that have been closed due to high levels of toxin in shellfish.
In early July, blooms of toxic algae, better known as red tide, resulted in the near-complete closure of shellfish harvesting in the coastal waters off of Maine, New Hampshire, and northern Massachusetts.
In response, NOAA provided emergency funding to Woods Hole Oceanographic Institution, in partnership with the University of Maine, to support sampling, mapping and forecasting of red tide location and intensity in the Gulf of Maine.
This funding, provided in part through the National Ocean Service's Center for Sponsored Coastal Ocean Research (CSCOR), is helping state managers focus sampling efforts in areas with the greatest potential to reopen for harvesting.
New England red tide typically occurs every year in the Gulf of Maine and is caused by an algal species called Alexandrium. Scientists prefer the term harmful algal bloom (HAB) to red tide, because these events may have harmful impacts even when the water is not discolored.
Alexandrium produces a potent toxin that accumulates in clams, mussels, and other shellfish. A severe and sometimes fatal illness, called paralytic shellfish poisoning, can occur in humans who eat shellfish contaminated with the toxin. States have well-established, rigorous shellfish monitoring programs to protect human health, so consumers are assured that commercially available shellfish are safe for consumption.
This year's red tide event was consistent with the seasonal forecast issued earlier this year by Woods Hole and North Carolina State University, which predicted a larger than normal Alexandrium bloom with landfall and effects on coastal resources largely dependent on wind patterns in May, June, and July. This forecast was based on runs of a predictive model, developed over the past decade with support from CSCOR and other agency partners.
NOAA's investment of over $23 million in New England red tide research since 1997 has aided management of these events through new tools for detecting and monitoring red tide, better communication among researchers and managers in the region, and seasonal and weekly forecasts of red tide location and extent.
While public health is a top concern with harmful algal blooms, these events also cause severe economic hardship to coastal communities. The historic red tide season of 2005 resulted in $23 million in lost shellfish sales in Massachusetts and Maine alone.