Are Some Shellfish Beds and Beaches Closed Needlessly? Mitchell Scientists Take a Closer Look
Could Northeast shellfish fisheries and beaches along Maine’s coast have fewer contaminated areas than currently reflected in closures and advisories? The possibility is being examined by scientists looking for methods to test the areas in question with greater precision.
Maine, New Hampshire and other New England states close thousands of acres of shellfish fisheries every year, due in part to contamination by fecal bacteria. A multi-institutional group of researchers is looking for ways to more accurately determine which specific spots in these vast closures actually have dangerous levels of fecal coliform bacteria.
The team is looking at beach advisory data as well, working closely with the Maine Healthy Beaches Program. Advisories are issued when levels of enterococci bacteria are deemed too high for safe swimming.
Using geographic information systems and data gathered over multiple years by Maine’s Department of Marine Resources (DMR), researchers are investigating multiple factors – rainfall, salinity, concentration of development – to pinpoint trouble spots across vast watery acreage. The how and why is a complex puzzle. Scientists are seeking answers in patterns of space and time.
“We are looking for spatial and temporal patterns in the bacterial levels. Are some locations consistently free of bacterial contamination and if so why? And when locations do have higher bacterial levels we are trying to understand why,” said Kate Beard-Tisdale, Professor in UMaine’s Spatial Informatics Group in the School of Computing and Information and a leader of the project.
Beard-Tisdale and colleagues are working closely with DMR, which tests waters along the coast and closes shellfish harvesting areas when harmful bacterial levels are exceeded. The use of the technology is one of many early steps being taken to help create an effective long-term coastal water quality strategy in the state, researchers say.
The spatial and temporal analysis of shellfish beds and beach water quality data is part of The New England Sustainability Consortium (NEST), which has mobilized the collective capacity of New England universities and colleges to strengthen connections between science and decision-making. Funded by the National Science Foundation to Maine EPSCoR and New Hampshire EPSCoR, NEST seeks to both better understand and find solutions to coastal water quality issues. Partnering with shellfish harvesters, state and local officials and non-governmental groups, scientists want to both understand how contamination happens and develop more scientifically accurate tests for bacteria. They also want to foster robust communication between researchers and stakeholders. Success of the project is dependent on collaboration with key project partners, especially state regulators and shellfish harvesters. There’s a lot at stake. Maine and New Hampshire depend heavily on the shellfish economy. In 2010, for example, Maine shellfish landings generated $347 million in revenue and tourism, of course, is the state’s top revenue generator, injecting billions into Maine’s economy, much of it focused on coastal activities.
The main concern is public health. Food-borne illness from seafood is on the rise in the Northeast and the nation as a whole, according to the Centers for Disease Control. Illnesses caused by swimming in bacteria-laden waters are harder to quantify, scientists say, since they usually present as gastro-intestinal sickness and can be mistaken for viruses. Researchers at UMaine’s Senator George J. Mitchell Center for Sustainability Solutions (Mitchell Center), College of the Atlantic (COA), University of New Hampshire (UNH) and other institutions are searching for meaningful answers.
Though Beard-Tisdale and other team members have much more research to do, they have some ideas about what makes some areas more likely to be contaminated by harmful bacteria than others. Right now, the criteria for closure of shellfish beds and beach advisories are simple: any area that gets two inches of rain or more (over what time period24 hours is closed pending water sample testing confirming water quality has returned to normal. The issue: testing for bacteria currently takes at least 24 hours, during which conditions in the water may change. And water quality within one testing area can vary.
So, while researchers know that rainstorms are responsible for higher bacteria levels, they are trying to better understand differences in rainstorm effects. Forests and wetlands, for example, can serve as natural filters for bacteria and other contaminants flowing downhill toward the coast. Development and an abundance of impervious surfaces like roads can lead to the opposite effect – a more direct bacterial runoff into coastal waters.
That’s where the technology, known as geographic information systems (GIS), comes into play. GIS supports combining many different types of data including satellite images to study how different factors from land use and land cover interact with the role of tides or changing salinity levels.
Translating the specialized space-time data into practical use for evaluation of coastal water quality is in progress. The need to minimize the time of shellfish bed closures is very important for economic reasons, but safety is the number one concern, researchers emphasize.
“The question is, can we decrease the time that an area is closed? Maybe someday that will be a bit more doable, but we can’t harvest unsafe clams or have an unsafe industry,” said Fuyu Xu, a research assistant on the project and PhD student in Spatial Information Science and Engineering.
NEST is managed by the Experimental Program to Stimulate Competitive Research (EPSCoR) at UMaine and UNH in partnership with College of the Atlantic (COA), University of New England (UNE), University of Southern Maine (USM), Great Bay Community College (GBCC), Plymouth State University (PSU), and Keene State College (KSC). This collaboration, funded by a three-year, $6 million award from the National Science Foundation, aims to strengthen the scientific basis for decision making for the management of recreational beaches and shellfish harvesting and to mobilize the collective capacity of New England universities and colleges to strengthen connections between science and decision-making. This scientific model seeks solutions to pressing societal problems with a focus on both human wellbeing and protection of the planet’s life support systems. A key component is collaboration with diverse stakeholders, in this case state and local government, shellfish harvesters and citizen scientists.