Abstract:Three growth models,Logistic,Gompertz and von Bertalanffy,were used as the candidates for fitting the growth model of eight morphometric traits of Portunus trituberculatus "Zhongning No.1" at six months,including body weight,body length,full carapace width,carapace width,body height,meropodit length of the claw,fixed finger length of claw and meropodit length of the first peraeopod.The paper aimed to establish the optimum growth equation of morphometric traits and study the growth regulation of it.Growth parameters embraced in foregoing models were estimated by Levenberg-Marquardt iteration method.Results showed that Logistic model is the best model to describe the growth of body weight of P.trituberculatus,with squared multiple correlation coefficient R2 reaching 0.999.However,the other morphometric traits were best confirmed by von Bertalanffy model,and the squared multiple correlation coefficient R2 ranged from 0.990 to 0.994.All optimum growth models of varying morphometric traits was significant(ANOVA,P<0.01).The growth limits computed by optimum growth models were,body weight 231.44 g,body length 84.45 mm,full carapace width 164.44 mm,carapace width 128.47 mm,body height 43.69 mm,and meropodit length of the claw 59.96 mm,fixed finger length of claw 90.89 mm,meropodit length of the first peraeopod 37.20 mm.What's more,the fast growth intervals and growth inflection points of varying morphometric traits were:body weight 2.14-3.91 months and 3.02 months,body length 0-2.05 months and 0.87 months,full carapace width 0-2.14 months and 0.93 months,carapace width 0-2.07 months and 0.94 months,body height 0-2.14 months and 1.04 months,meropodit length of the claw 0-2.3 months and 1.09 months,fixed finger length of claw 0-2.35 months and 1.11 months,and meropodit length of the first peraeopod 0-2.12 months and 0.98 months.The growth rate,the growth acceleration,the relative growth rate and the absolute growth rate were different among varying morphometric traits.In short,the process of body weight trait growth conformed to the characteristic of "slow-fast-slow",the other morphometric traits are "fast-slow".The above results can provide some references for the selective breeding and production of P.trituberculatus "Zhongning No.1".