Effects of Substrate Manipulations on Fish Assemblages in Southeastern Coastal Plain River Systems

Rivers in the Southeastern Coastal Plain are characterized as low-gradient, meandering systems with fine substrates. Coarse substrate tends to occur in the form of woody debris additions from the riparian zone, and provides highly productive habitat for macroinvertebrates, which in turn provide food for fishes. Coarse mineral substrates are rare, and are mostly in the form of anthropogenic additions. It is hypothesized that these areas act similarly to the woody debris, allowing for increases in macroinvertebrate abundance and diversity, which in turn allows for increases in fish abundance and diversity. To assess the impact of these course substrate additions, we are conducting sampling via electrofishing in stream reaches with and without substrate manipulations in the Ogeechee and Savannah River basins in southeastern Georgia. Fish community structure, abundance, diversity, Catch per unit effort (CPUE) and Gut Content Analyses (GCA) are being performed across the two habitat types to assess their influence on these consumers. Understanding the impact of this type of substrate manipulation on the fishery resource will allow for effective management decisions, and could applied to future habitat enhancement projects.