Estimation of biological parameter,biomass,sustaining yield for Coilia mystus in the offshore of Zhoushan

Based on the monthly length-frequency data of Coilia mystus obtained during 2003 in the offshore of Zhoushan, by applying the FiSAT Ⅱ(Version 1.2.2) and the result showed that the growth parameters of Von Bertalanffy growth equation was L∞=196.88mm, K=1.01, t0=-0.285. Natural Mortality Coefficient(M)was 1.548 from Pauly equation according to growth parameters and average water temperature. Total Mortality Coefficient (Z) was 3.06 that got from length-converted catch curve with biology datum. Fishing Mortality Coefficient (F) was ,1.512 and exploitation rate (E) was 49.41%. The Population was 53.15×109ind and Steady-state Biomass was 2.37×104t by using Length-Structured Virtual Population Analysis. Yield-per-recruit analysis and the value of yield-per-recruit analysis applying Beverton-Holt and Thompson-Bell model indicated, if the f-factor can be fell by 30%, than, we can get the most value to achieve the sustainable use of Coilia mystus.