Physicochemical factors affecting larval fish densities in mississippi river floodplain ponds, Louisiana (U.S.A.)

Abstract

We collected water-quality data from 15 artificial floodplain ponds along the Mississippi River during May 1988 and quantified shoreline length, shoreline sinuousity, volume, and depth variation. Ponds regarded as high-quality nurseries (based upon larval fish densities) contained higher dissolved oxygen concentrations and lower total organic carbon concentrations than ponds of lower nursery quality (p < 0.02). High-quality nurseries also maintained higher conductivity and turbidity than low-quality nurseries (p < 0.05). Results indicated that dissolved oxygen and pH probably fluctuated less in high quality nurseries and therefore provided better conditions for survival and growth of larval fishes. Total organic carbon and conductivity were directly related to pond morphometry (p < 0.004) and affected dissolved oxygen and pH in ponds. Large, high-volume ponds with sinuous shorelines and variable depths tended to contain both high conductivities and low total organic carbon concentrations. Pond morphometry may have affected water quality and subsequently determined the nursery value of artificial floodplain ponds.