Growth characteristics of Portunus trituberculatus cultured in ponds

In order to explore the growth characteristics and sexual differences of Portunus trituberculatus cultured in ponds, this study investigated the growth parameters of pond cultured P. trituberculatus at 1 to 6 months of age, and Logistic model was used to fit eight morphometric traits of P. trituberculatus, including body weight (BW), body length (BL), body height (BH), full carapace width (FCW), carapace width (CW), meropodit length of the claw (MLC), fixed finger length of claw (FFLC) and meropodit length of the first peraeopod (MLFP). The results showed that the growth was different between male and female of P. trituberculatus. The male grew faster at the early stage, while the female grew faster at the late stage of culture, and the mixed sex analysis lied in between. The R² values of all models of the morphometric traits were above 0.990 except MLC and MLFP in female and MLFP in mixed sex. The carrying capacity of BW of female and male were 290.27 g and 195.91 g, respectively, the fast growth interval of female and male were 2.74-5.10 months of age and 2.33-4.14 months of age, respectively, and the inflection points of female and male were 3.92 months of age and 3.24 months of age, respectively. In summary, the growth process of P. trituberculatus conformed to the "slow-fast-slow" pattern. Males entered the fast growth interval earlier than females, but had less duration of fast growth interval. This study provides the characteristics of different growth parameters of P. trituberculatus and the dominant stages for male and female of each parameter under the conditions of mixed sex culture, so as to provide reference data for the fine and efficient culture of this species.