Final Report Abstract

            Our project was a literature review of previous studies on selected river systems with the initial goal of consolidating information on native fish species and associated streamflow conditions.  Our intent was to examine and summarize the results of surveys from several unpublished reports into a form that is more accessible to other researchers.  We also drew from more recent journal publications if such studies were available.

            The reviewed information varied widely in extent and quality among the different rivers.  The most extensive studies were surveys for the lower Pit and North Fork Mokelumne rivers.  Those two studies contained data on fish abundance and distribution and streamflows for an array of locations in the watersheds, hence providing potential data for more detailed future examinations of fish-streamflow relationships.

            We did not discern any consistent, quantitative relationships pervading the range of studies we examined within the project time-frame.  However, the search for a general pattern was subordinated by our primary goal of broadly summarizing results of the studies in terms of fish and streamflow data.  Possibly, further evaluations focused on one or two data-rich studies may yet identify patterns between streamflow regimes and fish population robustness.  In our project, we achieved the broad goal of providing descriptive summaries of streamflows and fish population information for the selected rivers but we were unable to form a detailed analytical understanding based on that information.

            A secondary aspect emerging from our project was a simplified conceptual framework addressing the question of how streamflow regimes affect fish assemblages.  We suggest examples of parameters to utilize and questions to ask in regard to streamflow changes and their effects on fish species.  We also provide examples of working hypotheses that may aid our understanding--on broad temporal and spatial scales--how streamflow regimes and fish assemblages are related.