With support from NOAA, Woods Hole scientists see moderate spring, summer red tide for Gulf of Maine

March 25, 2013

New England is expected to experience a "moderate" red tide this spring and summer, which may result in closure of some shellfish harvesting beds to prevent possible illness to consumers who might eat contaminated food, according to Woods Hole Oceanographic Institution (WHOI) scientists funded by NOAA studying the toxic algae that cause the harmful blooms in the Gulf of Maine.

The 2013 forecast is the sixth annual Gulf of Maine red tide forecast NOAA and WHOI have issued. It is similar to the 2012 prediction, which was also classified as moderate. The other categories are limited and extensive, and refer to how much of the Gulf of Maine coast could be closed due to red tide. Extensive blooms last occurred in 2005 and 2008, when large areas of the Gulf of Maine were closed to shellfish harvesting.

Red tide, caused by the alga Alexandrium fundyense, produces a toxin that can lead to paralytic shellfish poisoning (PSP), which can result in serious or even fatal illness in humans who eat contaminated shellfish. States in affected areas conduct rigorous monitoring of toxin levels and ban shellfish harvesting to protect human health.

This year's outlook is based on the quantities of the A. fundyense in its cyst (dormant) state detected in Gulf of Maine sediments last fall. These data are analyzed using computer modeling to produce a range of bloom scenarios based on previous years' conditions.

"The continued annual advances in the Gulf of Maine red tide forecasts are important milestones for NOAA-funded research which aims to provide for the safe use of our coastal resources while protecting the public's health," said Quay Dortch, Ph.D., program coordinator, Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) program for NOAA. "These forecasts are an important building block in the operational HAB forecasting system NOAA is developing to reduce the effects of harmful algae."

New this year, the team also used a forecast developed from historical shellfish closure data as part of the development of the 2013 outlook. Examining this 34-year record of shellfish toxicity in the region, the 2013 bloom is expected to fall somewhere in the middle in terms of toxicity.

Real-time forecasts are updated on a weekly basis and additional information will be provided on the "Current Status" page of the Northeast PSP website. NOAA's National Weather Service is also providing extended hydrological and meteorological outlooks to accompany the bloom forecasts to aid in tracking the locations and potential effects to coastal shellfish beds. Project researchers regularly share their field observations and models with more than 150 coastal resource and fisheries managers in six states as well as federal agencies such as NOAA, the FDA and the EPA.

"Working with our partners, both in academia and at the state and federal levels, we've been able to gather more data  each year about red tide and its impacts -- from cyst abundance to toxicity records in shellfish to long-term measurements of ocean conditions from ships and moored instrumented buoys," said Donald Anderson, Ph.D., WHOI biologist. "The result is a second forecast that confirms the accuracy of our original approach. and is one more building block in our progress towards an operational forecasting system."

The forecast team emphasizes the need to consult state and local management agencies for updated harvesting closure information. In order to protect public health, shellfish beds are closed when toxicities rise above a level which may possibly cause PSP, often during the peak harvesting season. Thanks to effective monitoring by state agencies, there have been no illnesses from legally harvested shellfish in recent years, despite some severe blooms during that time. However, several people who ignored closure signs and illegally harvested and ate shellfish have been severely poisoned.

"Red tide is a chronic problem throughout the Gulf of Maine, affecting commercial and recreational harvesting interests," said Chris Nash, shellfish program manager for the New Hampshire Department of Environmental Services. "State agencies are responsible for monitoring toxicity levels in shellfish harvest areas and implementing harvest closures when needed. As a state manager, regional-scale, seasonal outlooks help us plan and use limited monitoring resources effectively. Ultimately, our goals are to protect public health and give consumers confidence in the quality of the seafood products they purchase from markets and restaurants, and these forecasts are useful in realizing those goals."

The forecasting project is a collaboration of investigators from NOAA's National Ocean Service, National Weather Service and National Marine Fisheries Service; WHOI, NCSU, University of Maine, FDA, Maine Department of Marine Resources, New Hampshire Department of Environmental Services, Massachusetts Division of Marine Fisheries, NERACOOS and the North Atlantic Clam Association. Funding is provided through the NOAA program Prevention, Control and Mitigation of Harmful Algal Blooms (PCMHAB), led by Dennis McGillicuddy (WHOI). Long term support forAlexandrium studies in the Gulf of Maine is provided by the NOAA NOS NCCOS Center for Sponsored Coastal Ocean Research (CSCOR) and NIEHS and the NSF through the Woods Hole Center for Oceans and Human Health.

The Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the oceans' role in the changing global environment. For more information, please visit www.whoi.edu

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