Production, biomass, and turnover of exploited mangrove clams (Geloina expansa, Mousson 1849) in Kendari Bay mangrove forest, Southeast Sulawesi Indonesia

Abstract

Geloina expansa is a front-runner commodity of the mangrove ecosystem. This species is notably experiencing ecological pressures in Kendari Bay. Accordingly, this study aims to determine their production, biomass, and turnover in the mangrove ecosystem. This research is hoped to provide empirical information that will aid in the formulation of the management strategy of mangrove clam resources in Southeast Sulawesi. Clam samples were collected at random in three selected sampling areas using a 1x1 m2 quadrat-transect sampling approach. The clams were measured for their shell length, total weight and weight of fresh meat. The clam meat was dried to obtain a shell-free dry mass. The production, biomass, and turnover of the clams were calculated using standard formulas. The population density of the clams ranged from 23.78 ind/m2 (October) to 77.44 ind/m2 (February), where the remaining months of observations showed similar values throughout. The clams biomass population in each size class ranged from 0.04 to 4.95 g/m2. The somatic production, as per the dry weight showed the highest value at 6.9 cm shell length (2.01g/m2/year). The lowest individual somatic production was found in the shell width of 9.7 cm (0.55 g/m2/year). The turnover rate (P/B) of the mangrove clam was 1.73/year. The density of the mangrove clams in the mangrove forest in Kendari Bay was found to be high. This was accompanied by high productions in the young or small-sized groups, peaking at a size smaller than the size where peak biomass was found.