en Stock assessment Stock assessment پژوهشي Orginal research papers <p>  The aim of the present study was to investigate the age structure, length-weight relationship, sex ratio, sexual maturity stages, growth parameters, natural and fishing mortality coefficients of three species of kilka including common, anchovy and bigeye kilka. The fork length–weight relationship of common, anchovy and bigeye kilka were calculated as W=0.000153 FL^2.37, W=0.000349 FL^2.18 and W=0.00160 FL^2.97, respectively. The parameters of the von Bertalanffy growth curve for length were L_∞ = 143.5 mm, K = 0.30 yr^-1 and t₀ = -1.02 yr for common kilka L_∞ = 151.9 mm, K = 0.28 yr^-1 and t₀ = -1.12 yr for anchovy kilka L_∞ = 148.6 mm, K = 0.46 yr^-1 and t₀ = -0.18 yr for bigeye kilka. The instantaneous coefficient of natural mortality of common, anchovy and bigeye kilka were estimated as 0.671, 0.633 and 0.881 yr^-1, respectively. The current exploitation rates of three species were estimated as 0.55, 0.41 and 0.26, respectively. The results suggest that common kilka stock is under over-fishing now. </p> Clupeonella cultriventris caspia, C. engrauliformis, C. grimmi, Growth, Sexual maturity stage 422 433 http://jifro.ir/browse.php?a_code=A-10-1-35&slc_lang=en&sid=1 G. Karimzadeh karimzadehg@yahoo.com 1003194753284600438 1003194753284600438 Yes B. Gabrielyan 1003194753284600439 1003194753284600439 No H. Fazli 1003194753284600440 1003194753284600440 No