Comparison of Growth in Generations F_1 and F_2 of Large Yellow Croaker Larimichthys crocea Bred Selectively

The body length and body weight were monthly measured in 3—10month old cage-cultured F1 and F2large yellow croaker Larimichthys crocea bred selectively to compare the growth performance between F1 and F2.The results showed that the F1 and F2 had mean coefficient variation of 0.11 in body length,mean coefficient variation of 0.33 and 0.32 in body weight,respectively,with the same trend.However,there was greater coefficient variation within one generation in body weight than that in body length.Further analysis revealed that the mean daily relative growth rate in body length was 0.40%in F1 and 0.37%in F2,and the mean daily specific growth rate 0.88%in F1 and 0.73%in F2.The mean daily relative growth rates in body weight was 0.47%in F1 and 0.46%in F2,and the mean daily specific growth rate 2.54%in F1 and 2.19%in F2,indicating that there was higher growth rate in F1 than in F2,two generations being characterized by a uniform growth.