Diversity and distribution of fishes in an intermittently open coastal lagoon at Shellharbour, New South Wales

A study was undertaken to examine the diversity and distribution of fish in an intermittently open coastal lagoon proposed for replacement by a marina development at Shellharbour, New South Wales. Eighteen sites, consisting of seagrass communities (mainly Zostera capricorni) and bare mud and sand substrata, were sampled by seine net at least once a week during both day and night over a three month period. Of the 985 fish caught, the most abundant species were sand mullet (Myxus eloes an ngates), tamar river goby (Afurcagobius tamarensis), yellowfin bream (Acanthopagrus australis) and mosquito fish (Gambusia holbrooki). Species diversity was found to increase after lagoon opening. Many more of the 27 species caught were foind in the more saline habitats (25sp.) than in the more brackish upland habitats (13sp.). more species were caught during the day (24sp.) than at night (16sp.). catches of juvenile (20-50mm) Myxus elongates increased significantly after lagoon opening. Catches of Afurcagobius tamarensis and Acanthopagrus australis also increased after lagoon opening but this was probably due to high turbidity and changes in estuary morphology rather than salinity. The sizes of the fishes caught suggest that the lagoon acts as a nursery area, although some adult fish were also found.