THE GROWTH AND OVARIAN DEVELOPMENT PATTERN OF POND-REARED SWIMMING CRAB PORTUNUS TRITUBERCULATUS

The most common method for farming swimming crab Portunus trituberculatus in China is pond culture; however, their growth performance and ovarian development under these conditions are unclear. This study was conducted to investigate growth parameters, gonadosomatic index (GSI), hepatosomatic index, and monthly variation in the ovarian development of pond-reared female P. trituberculatus. The results showed (1) a significant increase in body weight (BW) and carapace width (CW) of female P. trituberculatus mainly during June to October, and the highest growth rate and specific growth rate of BW and CW were found during June to July. In addition, a significantly positive correlation was also found between BW and CW for pond-cultured P. trituberculatus females; (2) GSI increased significantly during ovarian development of pond-reared female P. trituberculatus and the meanGSI of ovarian stage I was 0.32%, whereas themeanGSI of ovarian stage V reached 7.92%; (3) Female P. trituberculatus started their pubertal molt at the end of July and the peak pubertal molt occurred from mid-August to early September; females nearly completed their pubertalmolt inmid-October. Before pubertalmolt, ovarian development of pond-reared P. trituberculatus wasmainly at ovarian stage I during July to August; after the pubertal molt, females developed their ovaries quickly, with more than 80% at ovarian stage III inOctober. Asecond period of rapid ovarian development occurred at the end of January to the end of February, with ameanGSI reaching 5.25% at the end of February. From February to the end of March, no significant GSI changes were observed in female P. trituberculatus, indicating that the ovarian status of pond-reared female P. trituberculatusmatured by the end of February.