Pre-and post-flood feeding ecology of four species of juvenile fish from the Logan-Albert Estuarine System, Moreton Bay, Queensland

Abstract

The feeding ecology of the four dominant species of juvenile fish found in the Logan-Albert estuarine system are described in terms of the stomach contents of 675 fish examined over a 7-month period. Ontogenetic dietary changes and spatial, temporal and interspecific differences in diet were determined. Johniops vogleri and Polynemus multiradiatus were predominantly planktonic feeders. At an early stage of development, these fish fed mainly on copepods, which were progressively replaced by larger prey such as mysids and Acetes as the fish grew. Arius graeffei and Aseraggodes macleayanus were mainly benthic feeders. Spatial and temporal differences in diet were also evident for each species. These differences probably reflected changes in prey availability resulting from flood-induced changes to the salinity gradient. The potential for competition between Johniops vogleri and Polynemus multiradiatus was reduced by temporal partitioning of food resources as the fish grew.