Avoidance of inundated floodplain habitat by larvae of golden perch (Macquaria ambigua Richardson): Influence of water quality or food distribution?

Abstract

Golden perch (Macquaria ambigua) larvae were studied in a pond and an adjoining inundated floodplain to determine the influence of water quality and prey density on larval dispersion. Mean catches in both pump and light-trap samplers were greatest at midnight (4.08 and 11.58 larvae per sample, respectively), with relatively few larvae caught at dawn, midday and dusk. A total of 1421 larvae were collected in 320 samples from the pond (4.4 larvae per sample), whereas only 354 larvae were caught in 480 samples (0.7 larvae per sample) from the floodplain. Neither total plankton density nor the density of specific size classes of plankton were correlated with the distribution of golden perch larvae. Dissolved-oxygen concentrations were higher in the pond than on the floodplain and were significantly correlated with the spatial distribution of golden perch larvae. Tannin and lignin concentrations were also greatest on the floodplain. These results suggest that water quality may exert a greater influence than does food availability on the distribution of native fish larvae in artificially inundated floodplain habitats.