Population and age structure of the goby Stigmatogobius pleurostigma (Perciformes: Gobiidae) from the Mekong Delta

Abstract

This study was conducted in the Mekong Delta to provide new knowledge on the population and age structure of Stigmatogobius pleurostigma, a commercial target fish for catching. The von Bertalanffy growth parameters were L∞ = 8.6 cm, K = 0.83 yr-1, and t0 = -0.07 yr-1 basing on length frequency data analysis of 607 individuals. The species displayed 3.8 cm in the length at first capture, 3.61 yr in the longevity and 1.79 in the growth performance. The natural, fishing and total mortalities of the fish population were 2.31 yr-1, 1.17 yr-1 and 3.48 yr-1 respectively basing on the length-converted catch curve analysis. One recruitment peak was recorded in June in the study region, and the analyses of relative yield-per-recruit and biomass-per-recruit gave Emax = 0.704, E0.1 = 0.555 and E50 = 0.335. Four fish age groups were recorded in the present study (0.5+, 1.0+, 1.5+ and 2.0+). The species is a potential aquaculture candidate because of its high growth rate. The goby stock was overfishing since its exploitation rate (E=0.34) was higher than E50, suggesting that the mesh size of gillnets should be increased and avoid catching fish during the recruitment period for future sustainable fishery management.