Fish, Streams, and Water Quality

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...

In Pennsylvania, the USGS's water-resources roots date back to the late 1800's, with the initiation of streamflow gaging on the Susquehanna and Delaware Rivers and assessments of groundwater resources near Philadelphia. The USGS Pennsylvania Water Science Center continues to provide scientific information about the water resources of the Susquehanna River Basin, in cooperation with regional and...

Issue: As human population has increased, land-use changes have led to increases in nutrients (nitrogen and phosphorus) and sediment into the Bay. The excess nutrients cause algal blooms which contribute to water-quality impairments such as low oxygen or hypoxia (dead zones), and poor water clarity in the Chesapeake Bay. Management efforts to improve water quality focus on dissolved oxygen needed...

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 : Stream ecosystems are affected by a complex set of interacting terrestrial and aquatic stressors. With many streams experiencing degraded conditions that often correspond with increased anthropogenic activities, an important outcome of the Chesapeake Bay Program is to improve stream health. The USGS is conducting research to better understand the complex factors affecting stream health...

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...