US EPA

What is an ecological risk assessment?
An ecological risk assessment evaluates the potential adverse effects of human activities on the plants and animals that make up ecosystems. The risk assessment process provides a way to develop, organize and present scientific information so it is relevant to environmental decisions. When conducted for a particular place such as a watershed, the ecological risk assessment process can be used to identify vulnerable and valued resources, prioritize data collection activities, and link human activities with their potential effects. Risk assessments provide a focal point for cooperation among local communities and state and federal government agencies, and a basis for comparing various management options.

Aerial photograph of Waquoit Bay. Caption: The watershed consists of freshwater streams and ponds, saltwater ponds and marshes, pine and oak forests, barrier beaches and open estuarine waters. (Photograph not included)

Map of Cape Cod area. Caption: Cape Cod, Massachusetts with the Waquoit Bay area highlighted. The Waquoit Bay watershed covers 53 square kilometers (21 sq mi) on the south shore of Cape Cod. (Map not included)

Why is Waquoit Bay special?
Waquoit Bay is a shallow Cape Cod estuary fed by groundwater and freshwater streams. Because the Bay is close to the mixing zone between the warm waters of the Gulf Stream and the colder waters of the Labrador Current, many important fish species are found in the Bay. Alewives, bluefish, striped bass, winter flounder, menhaden, and tautogs all reside in the Bay for at least part of the year. The Commonwealth of Massachusetts has designated Waquoit Bay as an Area of Critical Environmental Concern. The Bay has also been designated as a National Estuarine Research Reserve. These designations help reduce existing and future human disturbances to the Bays watershed. Federal, state and local resource agencies, various regional and local citizen interest groups, and academic organizations are working together to preserve and restore the quality of the Waquoit Bay estuary and its associated freshwater ponds and rivers.

Picture of Least Tern Caption: Many Federally protected species such as the Least Tern nest or forage along Washbyrn Island in Waquoit Bay. (picture not included)

How can this valuable resource be protected?
The waters of Waquoit Bay and its associated rivers and ponds show signs of degradation such as eutrophication, habitat loss and resource depletion. Stressors in the Waquoit Bay watershed result from land use along the coast and from upland areas. This ecological risk assessment will analyze the stressors and resulting ecological effects in the Waquoit Bay watershed. The assessment promotes community awareness of ecological problems in the watershed and will provide information to resource managers, including government officials, organizations and the public so they can make more ecologically informed decisions. These activities promote environmentally beneficial results.

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Key stressors under evaluation are:

• nutrient enrichment (nitrogen loading)
• suspended sediments
• changes in water flow patterns
• inputs of toxic chemicals
• physical alteration of habitat

How is the ecological risk assessment being done?
Interested organizations collectively developed a management goal and a scientific study approach. Because many of the ecological effects observed in the Waquoit Bay watershed are related to loss of the once extensive eelgrass beds, the risk assessment research will focus on the causes of this loss, and ways to halt or reverse it. Relationships between nutrient enrichment and eelgrass loss are being analyzed. This will provide information to estimate risks associated with land-use decisions. A report describing the management goals for the WaquoitBay watershed and the analysis plan for the assessment will be available upon completion of the analysis describedabove.

Picture of Eelgrass bed with associated juvenile fish. Caption: Eelgrass beds, once extensive in Waquoit Bay are home to numerous fish, shellfish and other invertebrates. Eelgrass is highly susceptible to water quality conditions, requiring clear water that allows water to penetrate for photosynthesis. (Picture not included)

How will the results be used?
The Waquoit Bay Ecological Risk Assessment will help resource managers predict how changes in land use and human activity in the watershed will impact eelgrass growth. This will enable resource mangers to make decisions based on more information. This project is co-sponsored by the USEPAs Office of Water and Office of Research and Development as an effort to bring the science of risk assessment into the local community decision-making process.

The U.S. Environmental Protection Agency thanks the following for their participation in this case study:

• Waquoit Bay National Estuarine Research Reserve
• Association for the Preservation of Cape Cod
• Cape Cod Commission
• Citizens for the Protection of Waquoit Bay
• Massachusetts Coastal Zone Management
• Massachusetts Dept of Environmental Protection
• National Marine Fisheries Service
• National Oceanic and Atmospheric Administration
• US Army Corps of Engineers
• US Fish and Wildlife Service
• Waquoit Bay Watershed Intermunicipal Committee
• US Geological Survey
• Massachusets Division of Fisheries and Wildlife
• Buzzards Bay Project
• Town of Mashpee
• Town of Falmouth