Side Channels in Large River Systems

The ecological role of side-channels in Large River systems is not well understood.  We have analyzed multi-year data sets collected by the Long Term Resource Monitoring Program and the Open Rivers and Wetlands Field station to determine water quality and fish use.  Side channel complexes were investigated and data analyzed based on macro-habitat features (e.g. presence of closing structures).  Diversity estimates were calculated from fish abundance data collected within each side channel complex and species common to side channels were identified.  Further analysis compared species diversity between four predominant aquatic areas (i.e., main channel border, wing dike, open-side channel, and closed-side channel) associated with large river systems. Telemetry data were used to determine the use of side channels as migratory pathways for large river fish species.  Further observations of water quality within the side channels indicated differences in meso-habitat that may influence observed fish use.  The results of this study identified dominant adult and young-of-the-year side channel species, suggested that diverse side channels will support the most diverse large river fish community, and highlighted the lack of knowledge on the ecology of side channels in large river systems.