Fish Health and Toxic Contaminants

Issue: The Chesapeake Bay Watershed (CBW) is experiencing effects of climate (warming temperatures and shifting precipitation patterns) and land-use/land-cover (LULC; transition from forest or agriculture to developed lands) change, and these trends are likely to continue under future scenarios of warming and population growth. Stream biodiversity may be vulnerable to ongoing and future climate...

Issue The USGS has a long-term research effort that identified endocrine disruption in smallmouth bass (SMB) in the Chesapeake Bay watershed. Endocrine disruption can cause many changes in fish, including intersex characteristics where fish develop characteristics of the other sex, such as immature eggs forming in males. An overview by USGS of endocrine disruption in fish found the condition...

Identifying and tracking the status of, and trends in, stream health within the Chesapeake Bay watershed is essential to understanding the past, present, and future trajectory of the watershed’s resources and ecological condition. A team of USGS ecosystem scientists is meeting this need with an initiative to track the status of, and trends in, key indicators of the health of non-tidal freshwater...

Issue: Chemical contamination of riverine ecosystems is a global concern, with potentially negative effects for human and ecological health. Land management activities (e.g., Best Management Practices; BMPs) are an important tool that can be used to reduce point and non-point sources of pollution. The Chesapeake Bay Program (CBP) has goals for (1) reducing toxic contaminants and (2) reducing...

Issue: Studies in the Chesapeake Bay Watershed have documented the exposure of fish to toxic contaminants including endocrine-disrupting compounds (EDCs) - compounds which can alter normal hormonal function in organisms. Given the importance of fisheries to the economic and environmental health of the Watershed, observed endocrine disruption and fish kills in the Watershed have raised public and...

Issue The widespread use of pesticides and fertilizers, application of biosolids and manure, and large-scale animal feeding operations result in contaminant mixtures occurring in streams and rivers (figure 1). These nonpoint sources are affected by multiple processes (such as stream discharge, seasonality and management practices) that influence contaminant occurrence in surface and groundwater...

Fish mercury data from State monitoring programs and research studies within the Chesapeake Bay were compiled and summarized to provide a comprehensive overview of the variation in fish mercury concentrations among species and habitats within the watershed. These data are put into context with existing health benchmarks for humans, birds, and fish. Scientists also provide a roadmap for an...

Issue: The Chesapeake Bay Program (CBP), through the Strategic Review System (SRS), reviews progress toward the 10 goals and associated outcomes of the Chesapeake Watershed Agreement. Each outcome is managed by a specific CBP Goal Implementation Team and their associated workgroups. During review of each outcome every two years, a workgroup is responsible to prepare materials for (1) summarizing...

Issue: Effects of exposure to estrogenic-chemical contaminants have been observed in many fish species worldwide. One effect is described as “intersex” because fish will take on characteristics of the other sex, such as immature eggs forming in male fish. Studies in the Chesapeake Bay watershed have also identified the exposure of fish to endocrine-disrupting compounds. The estrogenic-endocrine...

Issue: The Chesapeake Bay Program has a goal to reduce the impacts of toxic contaminants on living resources in the Bay and its watershed. USGS leads the toxic contaminant outcome on research to increase our understanding of the impacts and mitigation options for toxic contaminants.

Issue: Millions of people rely on the Potomac River for drinking water and recreational opportunities. The Potomac is Maryland’s most popular freshwater fishing destination, and the second largest river that enters the Chesapeake Bay. Restoring fisheries is also an important goal for the Chesapeake Bay Partnership restoration efforts.

Refinement of the existing national-scale “de facto reuse incidence in our nation’s consumable supply” (DRINCS) model, complemented by field measurements, provides a screening tool to understand human and wildlife exposure to toxicants and pathogens associated with the incidental reuse of treated wastewater in the Shenandoah River watershed. The model results can be accessed in a companion web...