Estimation of Maximum Sustainable Yield Using Production Modeling: A Stock Appraisal of Indian Oil Sardine (Sardinella longiceps) from Pakistani Waters

Time series of catch and effort data were analyzed to estimate the Maximum Sustainable Yield (MSY) of Indian oil sardine, Sardinella longiceps (Valenciennes, 1847, Family: Clupeidae), fishery resources from Pakistani waters. The catch and effort data (1994 - 2009) were analyzed by CEDA (catch and effort data analysis) consists of Fox, Schaefer and Pella Tomlinson models and ASPIC (a surplus production model incorporating covariates) contain Fox and Logistic models. The average annual landings of S. longiceps stocks were 38 353 t while the highest and lowest 65 050 t in 1994 and 26 937 t in 2009 was recorded correspondingly. The MSY was estimated using the initial proportion (IP) value of 1 because the starting catch was approximately 100% of the maximum catch.The estimated values of MSY using CEDA with the Fox model under three error assumptions of normal, log-normal and gamma were 25 860.07 t (R2 = 0.864), 26 812.65 t (R2 = 0.836) and 26 665 t (R2 = 0.85), respectively. The MSY values with Schaefer and Pella Tomlinson models under two error assumptions normal and log-normal were 29 160.13 t (R2 =0.84) and 30 455.5 t (R2 =0.807), respectively. The values of Schaefer and Pella Tomlinson models were the same. The gamma error assumption showed minimization failures for Schaefer and Pella Tomlinson models. The estimated values of MSY using ASPIC computer software with two surplus production models of Fox and logistic were 28 180 t (R2 =0.915) and 33 260 t (R2 =0.897) respectively. The estimated values of MSY from CEDA were about 26 000 - 31 000 t and from ASPIC were 29 000 - 31 000 t. The estimated MSY values of CEDA and ASPIC were higher than the most recent catch. This shows that the stocks are in a safe condition.