Habitat selection of juvenile robust redhorse Moxostoma robustum: implications for developing sampling protocols

Robust Redhorse, described originally in 1870, went unnoticed until 1991 when they were rediscovered in the lower Oconee River, Georgia. This research evaluated one hypothesis (habitat use) for explaining the absence of juveniles (30 mm 410 mm TL) from samples of wild-caught robust redhorse. Two mesocosms were used to determine if juvenile robust redhorse use available habitats proportionately. Pond-reared juveniles were exposed to four, flow-based habitats (eddies = - 0.12 to -0.01 m/s, slow flow = 0.00 to 0.15 m/s, moderate flow = 0.16 to 0.32 m/s, and backwaters). Location data were recorded for each fish, and overall habitat use was evaluated with a Log-Linear Model. In winter, the fish preferred eddies and backwaters. In early spring the fish preferred eddies. Catch of wild juveniles may be improved by sampling eddies and their associated transitional areas.