Estimation of Maximum Sustainable Harvest Levels and Bioeconomic Implications of Babylonia spirata Fisheries in Pakistan by Using CEDA and ASPIC

Abstract

Pakistani fisheries sector is a victim of "the tragedy of the commons". This sector performance matches with the description of Gordon-Schaefer Model. Therefore, in this study maximum economic harvest levels of B. spirata from Sindh, Pakistan are estimated by using maximum sustainable yield (MSY) proxy for maximum economic yield (MEY). For this purpose, fishery input (effort) and fishery output (catch) data of B. spirata is analyzed by using two specialized fishery software CEDA (catch and effort data analysis) and ASPIC (a stock production model incorporating covariates). Three surplus production models viz. Fox Model, Schaefer Model and Pella-Tomlinson Model were used in CEDA along with three error assumptions viz. normal error assumption, log normal error assumption and gamma error assumption. Whereas, in ASPIC two surplus production models viz. Fox Model and Logistic Model were employed for data analysis. MSY estimates for B. spirata by using CEDA and ASPIC were between 80-182t and 180-202t correspondingly. The calculated MSY range does not overlap so much. Furthermore, CEDA remained conservative in MSY estimation in contrast to ASPIC. ASPIC results showed higher values of R 2 . Thus, considering MSY estimates, it is concluded that for maximum economic gain target reference point for MSY in Pakistani marine waters along the Sindh coast is between 175-180t. However, harvesting of this fishery resource beyond 200t should be considered as limiting reference point which will result in economic loss.