The effect of turbidity on foraging behavior of the drift-feeding minnow, rosyside dace (Clinostomus funduloides).
Zamor, Richard M.
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thSince the turn of the 20 century, streams in the Southeast have experienced increased sediment loads and turbidity. Unfortunately, the effects of turbidity on non-game fishes are not well understood due to a lack of data. Consequently, I examined the effects of turbidity and seasonal temperatures on foraging success in rosyside dace (Clinostomus funduloides). I conducted experiments in an artificial stream and recorded reactive distance and prey capture success. Turbidity had a strong negative effect on both reactive distance (spring/autumn – 22p<0.0001, r=0.96; summer – p<0.0001, r=0.90) and capture success (spring/autumn – 22p<0.0001, r=0.88; summer – p<0.0001, r=0.70). Rosyside dace had longer reactive distances and greater capture success at spring/autumn temperatures than at summer temperatures. Median effective concentrations for reactive distance (spring/autumn – 9.892 NTU, summer – 9.2245 NTU) indicated that disturbed reaches in the natural range of rosyside dace would cause 50% reductions in their reactive distances 50% of the time. These results indicate that turbidity has immediate negative effects on the foraging success of rosyside dace and establishes that these effects may change seasonally.