Fish, Streams, and Water Quality

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 natural cycle of water flow, known as the flow regime, is one of the primary habitat conditions needed for healthy biological communities in streams. However, human activities have drastically altered the natural flow regime of most of the world’s rivers and streams, including those in the Chesapeake watershed, which has resulted in changes not only to the natural habitat but also...

Issue: Atmospheric deposition is one of the principal sources of nitrogen to the Chesapeake watershed with implications for patterns of nutrient loading, anoxia, and eutrophication in the Bay.

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...

Scientists determined the risk factors associated with smallmouth bass melanistic skin lesions on smallmouth bass in the Susquehanna and Potomac Rivers, in the Chesapeake Bay watershed. A new virus, which appears to be a member of an emerging viral family, the Adomaviridae, was identified in the lesions. Questions remain about the full characterization of the virus and the role of environmental...

Issue: Trends in nitrogen and phosphorus, and the complex factors affecting their change, provide important insights into the effectiveness of efforts to reduce nutrients from reaching the tidal waters of the Bay. The nutrient reductions are needed to improve water-quality conditions in the tidal waters for fisheries and submerged aquatic vegetation.

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 (CBP) is pursuing restoration efforts to improve habitats and associated water quality for fisheries, both in the watershed and estuary. Excess sediment decreases light in tidal waters for submerged aquatic vegetation, harms oysters, carries contaminants, and impairs stream health throughout the watershed. The CBP is implementing management actions and policies...

Issue: Native brook trout ( Salvelinus fontinalis ) are of great ecological, cultural, and economic importance in eastern North America, and their restoration is a focus of the Chesapeake Bay Program. Introduced, non-native species can jeopardize native brook trout, and more information on these effects are needed.

The U.S. Geological Survey (USGS) has developed the nontidal network mapper to share the short-term (2009-2018) water-year nutrient and suspended-sediment load and trend results for the Chesapeake Bay Program’s (CBP) non-tidal network (NTN). The network is a cooperative effort by USGS, the U.S. Environmental Protection Agency (USEPA), and agencies in the states of the Chesapeake watershed and the...

Issue: Excessive nitrogen and phosphorus in Chesapeake Bay since the 1950s have contributed to low dissolved oxygen leading to fish kills, and poor water clarity and associated loss of submerged aquatic vegetation. The Chesapeake Bay Program partnership has been working to improve aquatic conditions in the Bay and its tidal tributaries, and streams in the watershed, by reducing inputs of nutrients...