A total of 45 fish species and 55 decapod species were collected by seine net from the seagrass beds in Cockle Bay. The dominant fish species were Leiognathus bindus, Sillago maculata burrus, Favonigobius reichei, Lethrinus sp., and Pelates sexlineatus and these accounted for 87.5% of the total numbers. Dominant decapod taxa were Paratya, Rhynchocinetes and Brachycarpus. These were primarily small species or early juveniles of larger species. Temporal variation in both species composition and abundance was large: the peak number of fishes and decapods occurred in April 1999 and October 1999, whilst biomass was highest in April 1999. Fish and decapod numbers as well as biomass were lowest in August 2000. Temporal changes in the abundance of fishes and decapods corresponded with that of seagrass biomass and abundance of food organisms.