Assessing Trends in Fish Communities within and between Several Large US River Systems

Large Rivers throughout the U.S. are imperiled from many factors at the local scale (e.g., instream habitat degradation) to landscape and continental scale (climate change). Targeted, hypothesis-driven long-term monitoring can provide information to aid conservation and management decisions and can be critical to assessing changes in fish community structure and populations in Large Rivers. Scientists from the Colorado, Columbia, Illinois, Mississippi, and Tallapoosa Rivers have come together in a work group to improve our understanding of existing large river monitoring programs and to formulate recommendations on ways to improve collaboration and comparability across programs. We examined existing large river fishery monitoring programs in these river systems and used the data from these programs to develop community and population metrics for each river and examined trends in these metrics within and between rivers and over time. In addition, we will address whether fish assemblage structures are changing through time, whether fish communities are structured similarly among rivers, and whether they are changing in similar ways among rivers. We are also examining the monitoring programs themselves regarding management objectives, regulatory information needs, conceptual models, underlying hypotheses associated with the monitoring activities, and how these factors are affecting their sampling designs and procedures.