Comparisons between the influence of habitat type, season and body size on the dietary compositions of fish species in nearshore marine waters

摘要: Fish were collected from over bare sand in nearshore shallow waters at three sites that varied the extent to which they exposed wave activity and located within a 45-km stretch on lower west coast of Australia. Sampling was undertaken 4-6-week period each season. The volumetric contributions different prey stomach contents mouth characteristics four species, i.e. Sillago bassensis vittata (Sillaginidae), Spratelloides robustus (Clupeidae) Pseudorhombus jenynsii (Bothidae), determined. Overall, dietary compositions species differed significantly other those fish both consecutive seasons also different. In comparison with S. bassensis, morphologically similar fed relatively greater polychaetes than zooplankters, presumably reflecting part its ability extend upper jaw downwards towards benthos. typically targeted calanoid copepods plankton, whereas P larger benthic taxa, large differences morphology feeding behaviour these species. Although diets strongly influenced by habitat type season, former variable slightly more important for However, reverse applied robustus. Season composition P. one site it regularly caught. two underwent pronounced size-related changes, would help distribute food resources among individuals size classes contrast, all S predominantly or exclusively seasons, except most sheltered winter when zooplankters not found samples taken water column. seasonal variations recorded this study imply are able feed opportunistically, characteristic be particular value live where relative abundance types varies