FISHERY STOCK ASSESSMENT OF MEGALASPIS CORDYLA BY USING NON-EQUILIBRIUM SURPLUS PRODUCTION MODELS IN THE ARABIAN SEA COAST OF PAKISTAN
S. Razzaq1, M. A. Kalhoro*1, A. M. Memon2, M. A. Buzdar1, M. Shafi1, F. Saeed1 and A. Baloch1
1Faculty of Marine Sciences, Lasbela University of Agriculture, Water and Marine Sciences, Uthal, Balochistan, Pakistan
2Sindh Fisheries Department Hyderabad, Sindh, Pakistan
*Correspondence author: muhsanabbasi@yahoo.com

ABSTRACT

Catch effort data for Megalaspis cordyla of Pakistani marine fishery from 1996 to 2009 was analyzed using the special surplus production models in order to grasp the inventory situation of fishery. The special tools were used using catch and effort data analysis (CEDA) and a stock production model incorporating covariates (ASPIC) for estimate the maximum sustainable yield (MSY). Three surplus production models of Fox, Schaefer and Pella-Tomlinson with three error assumptions, usually gamma, normal and log normal are used in CEDA. The Fox model calculated these MSY for normal, lognormal and gamma error hypotheses as 2592 tons (CV = 0. 154, R2 = 0. 593), 2806 tons (CV = 0. 104, R2 = 0. 620) and 2673 tons (CV = 0. 134, R2 = 0. 608) respectively at the initial proportion (IP) of 0.7. The estimated MSY using normal and lognormal error assumptions for the Schaefer and Pella-Tomlinson models were 2887 tons (CV= 0. 178, R2= 0. 579) and 3248 tons (CV = 0. 072, R2 = 0. 606). Whereas, the gamma error resulted minimization failure of both models here. The calculated parameters of the Fox model in ASPIC by way of MSY, CV, R2, FMSY and BMSY were 2578 tons, 0.108, 0.743, 0.132 and 19520 tons, and corresponds to the values 2477 tons, 0.142, 0.738, 0.101 and 24550 tons per year calculated by the logistic model. Present estimated MSY values are lower than annual catch is shows that the stock of this fish is in overexploitation state. Present findings would be helpful to fishery managers for sustainable fishery.
Keywords: Pakistan; stock evaluation; fishery management; Megalaspis cordyla.