The study sought to determine the efficient management of fisheries resources (Coreoperca herzi) by estimating the potential yield (PY), which means the maximum sustainable yield (MSY) based on the optimal stock, in the mid-upper region of the Seomjin River watershed from August 2008 to April 2009. To estimate the population ecological characteristic, the age determined by counting the otolith annuli. The stock assessment was conducted by the swept area method and PY was estimated by a modified fisheries management system based on the allowable biological catch (ABC). Also, the yield-per-recruit analysis was used to review the efficient management of fisheries resource. The von Bertalanffy’s growth parameters estimated from a non-linear regression method were L∞=19.68 ㎝, W∞=188.64 g, K=0.17/year and t0=-1.46 year. Therefore, Growth in length of the fish was expressed by the von Bertalanffy's growth equation as Lt = 19.68(1-e-0.17(t+1.46)) (R2=0.997). The annual survival rate (S) was estimated to be 0.666 year-1. The instantaneous coefficient of natural mortality (M) of estimated from the Zhang and Megrey method was 0.346/year. Concerning current fishing intensities, the instantaneous coefficient of fishing mortality (F) was estimated to be 0.061/year; yield-per-recruit analysis estimated the current yield per recruit as 4.124g with F and the age at first capture (tc). The instantaneous coefficient of fishing mortality for ABC (FABC) based on the current tc and F was estimated to be 0.401 year-1, therefore, the optimal fishing intensities could be achieved at the higher fishing intensity for Coreoperca herzi. The calculated annual stock of coreoperca herzi was 3,048 kg, the potential yield was estimated to be 861 kg with tc and FABC at the fixed current level. Using yield-per recruit analysis, if F and tc were set at 0.643/year and 3 age, respectively, the yield per recruit would be predicted to increase 3.4-fold. From 4.12 g to 13.84 g.