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Gulf of Maine Red Tide Bloom Expected to Be Similar to Past Three Years

May 11, 2015

New England’s spring and summer red tides will be similar in extent to those of the past three years, according to the 2015 Gulf of Maine red tide seasonal forecast. The forecast is the eighth seasonal Gulf of Maine red tide forecast funded by NOAA and issued by scientists from the Woods Hole Oceanographic Institution and North Carolina State University.

The forecast is part of a larger NOAA effort to deliver ecological forecasts that support human health and well-being, coastal economies, and coastal and marine stewardship.

Red tide, a type of harmful algal bloom (HAB) caused by the alga Alexandrium fundyense, produces a toxin that can lead to paralytic shellfish poisoning, which can result in serious or even fatal illness in humans who eat contaminated shellfish. In 2005, an unusually large red tide event caused $23 million in lost shellfish sales in Massachusetts and Maine.

States in affected areas conduct rigorous monitoring of toxin levels in shellfish and, when necessary, ban harvesting to protect human health. The seasonal forecast, which is generated by modeling how algal cysts will respond to predicted ocean conditions, is used to guide the state monitoring.

Woods Hole will also maintain three robotic HAB sensors called environmental sample processors (ESPs) at locations along the Maine coast throughout the spring and summer. This is the first year the Maine Department of Marine Resources (DMR) will provide their direct measurements of shellfish toxicity to researchers for comparison with estimates derived from near-real time ESP data on Alexandrium cells to try to predict toxicity in shellfish.

“We are working with the researchers at Woods Hole to further explore the relationship between the direct shellfish toxicity measurements onshore and the predictions of toxicity from the ESPs located offshore,” said Kohl Kanwit, director of the Bureau of Public Health for the Maine DMR. “The ESPs are not a replacement for state-run programs that monitor naturally occurring marine toxins in shellfish, but they can possibly increase our program efficiency in the future by providing automated data collection that can inform on-the-ground decision making.”

“This partnership on the Gulf of Maine seasonal HAB forecast and use of ESPs to detect toxic red tide offshore are examples of NOAA’s role in improving ecological forecasting capabilities along our coasts,” said Holly Bamford, Ph.D., assistant NOAA administrator for NOAA’s National Ocean Service performing the duties of the assistant secretary of commerce for conservation and management. “Advance warning of toxic HAB events enables proactive actions to protect coastal economies, making the region more resilient to red tide outbreaks.”

In addition to the seasonal forecast, NOAA funds Woods Hole and North Carolina State University to issue weekly updates throughout the bloom season. Updates report bloom extent, trajectory, and intensity. Scientists also report cell abundance and toxin concentrations transmitted in real-time from ESPs strategically placed offshore of shellfish beds. NOAA and Woods Hole developed the toxin detection sensors. Updates are distributed to more than 150 coastal resource and fisheries managers in six states as well as federal agencies such as NOAA, the Food and Drug Administration and the Environmental Protection Agency. Summaries are available at

Participants in the effort to build a Gulf of Maine HAB forecasting and observing system include: Woods Hole Oceanographic Institution, NOAA’s National Centers for Coastal Ocean Science (NCCOS), NOAA’s Integrated Ocean Observing System program, NOAA’s Office of Coast Survey, NOAA’s Center for Operational Oceanographic Products and Services, NOAA’s Northeast River Forecast Center, North Carolina State University, the University of Maine, the Monterey Bay Aquarium Research Institute, the Northeastern Regional Association of Coastal and Ocean Observing Systems, and the states of Maine, Massachusetts and New Hampshire.

NCCOS funding is supporting the transition of HAB forecasts and sensors to operations. Additional support has been provided by provided by U.S. Environmental Protection Agency, Woods Hole Center for Oceans and Human Health through funding from the National Science Foundation and the National Institute for Environmental Health Sciences, the Environmental Protection Agency, the Massachusetts Institute of Technology Sea Grant Program, and Tom and Robin Wheeler.

NOAA’s mission is to understand and predict changes in the Earth’s environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on Twitter, Facebook, Instagram, and our other social media channels.

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 ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean’s role in the changing global environment. For more information, please visit