Density, biomass and species composition of fish in a subtropical Rhizophora stylosa mangrove forest

Abstract

Juvenile and adult fish were sampled from within a subtropical Rhizophora stylosa mangrove forest in Tin Can Bay, Australia, every second lunar month from November 1991 to November 1993. On all sampling occasions replicate samples were taken on two consecutive nights. In all, 3320 fish were collected, representing 42 species and weighing 141 498 g. Significantly fewer fish were caught on the second night than on the first night. Economically important fish of the Families Atherinidae, Mugilidae, Gerreidae, Sparidae and Sillaginidae represented >76% by number and >74% of the total weight caught. The mean density of fish in the forest was 0.04 ± 0.01 m^-2, with a biomass of 1.3 ± 0.2 g m^-2. This is lower than that found in similar studies on other mangrove communities. The fish community was dominated by detritivores and intermediate carnivores, many of which are of economic value. Although the fish use of this subtropical R. stylosa forest was low, this habitat is important as a feeding and nursery area for fish species that contribute to the fisheries value of the region.