Fishes of a subtropical Australian saltmarsh and their predation upon mosquitoes

Synopsis The fishes occurring in a subtropical Australian saltmarsh were studied from January to December 1984 to determine the seasonal abundance and feeding of the most common species. Wide variations in pool water levels and salinity were recorded. Eight species of fish were collected, four of which are of economic importance to fisheries. Three taxa, Gambusia affinis, Pseudomugil signifer, and gobiids predominated in terms of abundance and occurrence. The abundance of fishes fluctuated markedly on a seasonal basis with few fish being taken in winter and spring (June–November) when pool water levels were low. Diets of the most common species were similar with terrestrial foods forming an important component of all diets. Feeding activity was highest in summer (December to February) when mosquito larvae, copepods, and larval coleopterans formed a large proportion of the fishes' diets. Results from the present study indicate that fish important to commercial fisheries rarely utilise the upper littoral saltmarsh habitat and that resident fishes are unlikely to effectively control mosquito larvae in saltmarsh.