Fish, Streams, and Water Quality

Issue: The Chesapeake Bay Program (CBP) partnership is striving to improve water-quality conditions in the Bay by using a variety of management strategies to reduce nutrient and sediment loads. The partnership uses monitoring results and modeling tools to implement management strategies, relying on the scientific community to synthesize existing information and direct new research to address...

Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses...

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...

Groundwater discharge zones are important spawning areas for fish because they provide a thermally stable habitat. Research at three streams in the Chesapeake Bay Watershed with areas of focused groundwater discharge revealed that groundwater also is a source of phytoestrogens and herbicides that could result in fish exposure during sensitive life stages.

Issue The Chesapeake Bay Program (CBP) partnership is striving to improve water-quality conditions in the Bay and its tidal waters. The partnership needs to understand water-quality conditions in different tributaries to help assess the influence of nutrient-reduction practices and progress toward attaining water-quality standards.

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.