???????????????????????????????????????????????????? ?????????????????????????????????????????????????? (Scylla paramamosain)

Abstract

Mud crab (Scylla paramamosain) has high potential to be developed as an economic aquaculture species that can create future jobs and generate income for Thailand. The major challenge in creating and developing a complete mud crab farming chain is the shortage of berried female spawner in the country. This study aims to investigate 1) the embryonic development of mud crabs from a captive culture system, 2) suitable substrate to produce berried female crabs using a closed water recirculation system, 3) the effect of female crab sizes on the production efficiency of berried female broodstock, and 4) a relationship between crab sizes and reproductive efficiency including egg weight, fecundity, egg diameter, and number of Zoea. Altogether, 281 wild and semi-intensive farmed gravid female crabs (Stage III-IV), were used in this study to incubate in the recirculation broodstock housing system at Prince of Songkla University, Pattani Campus. Sizes of gravid female crabs used in this study were 120.20�9.24 mm carapace width, 83�6.41 carapace length, and 349.53�81.64 g total weight. The mud crabs were fed daily fed with blood cockle and water parameters were measured fortnightly. Study on embryonic development indicated 6 different stages viz., cleavage, blastula, gastrula, eyespot-pigmentation, thoracico-abdominal, and heartbeat-prehatching stages. The incubation period was 9-11 days to develop from first spawning to hatching into zoea at the salinity and water temperature of 32-35 ppt and 27-30 �C, respectively. Average diameter and volume of the eggs on the first spawning day were 348.71�15.85 �m and 21.51�3.04 �106 �m3, respectively. Average diameter and volume of eggs on the 8th day, a few days before hatching to zoea stage, were 412.38�19.10 �m and 35.97�5.12�106 �m3, respectively. Moreover, during the period of embryonic development phase, diameter and volume of crab eggs increased significantly (p????? (Scylla paramamosain) ???????????????????????????????????????????????????????????????????????????????????????????????????????????????? ???????????????????????????????????????????????????????????????????? ??? ????????????????????????????????????????????????? ???????????????????????????????????????? 1) ????????????????????? 2) ???????????????????????????????????????????????????????????????????????????????? 3) ????????????????????????????????????????????????????????? ??? 4) ????????????????????????????????????????????? ?????????????????????????? ?????? ?????????? ????????? ?????????????????????????????? ???????????????????????????????????????????????????????????????????????? ???????????????????????????????????????????????????? ??????????????? ??????????????????????????????????? 3-4 (Stage III - IV) ????????????????????????????????????????????????????????????????? ????????????? 281 ??? ????????????????????????????????? 120.20�9.24 ????????? ?????????????????????? 83�6.41 ????????? ???????????????? 349.53�81.64 ???? ??????????????????????????????????????????????????????????????? 2 ?????????????????????????????????????? ????? ??????????????????????????????????????????????? 6 ???? ??????? ??? ?????????? (Cleavage stage) ???????????? (Blastula stage) ??????????? (Gastrula stage) ?????????????????????? (Eyespot-pigmentation stages) ??????????????????????????????? (Thoracico-abdominal stages) ??????????????????????-?????????? (Heartbeat-prehatching stages) ???????? ??????????????????????????????????????????????????????????????????????????????? 9-11 ??? ????????????????? 32-35 ppt ??????????? 27-30 �C ??? ????????????????????????????????????????????????????????? 348.71�15.85 ????????? ??? 21.51�3.04 �106 ????????????????? ???????? ???????????????????????????????????????????????????????? 8 ??????? 412.38�19.10 ????????? ??? 35.97�5.12�106 ????????????????? ??????????????????????????????????????????????????????????????????????????????????????????? (p130 ??????????????? ????????????????????? ????????? ?????????????????????????? ???????????????? ??????????? ?????????????????????????? ??????? 87.72�17.95 ????, 4.37�0.92�106 ???, 350.94�16.10 ?????????, 21.92�3.00 x106 ?????????????????, 69.78�17.79 ??????????? ??? 3.06�0.84�106 ??? ???????? (p0.05) ?????????????????????????????????????????????? ?????????? ?????????????????? ?????????????????? ?????????????????????????????????? ?????????? ??????????????????? ????????? ?????????????? ????????????????????????????????????????? (p0.01) ????????????????????????????? ??????????????? ?????????????????????????????? ??????????????????????? ?????????? ?????????????????????????????????????????????????????????????????????????? (277.83�35.72 ?????????) ??????????????????????? ???????? ?????????????????????????????? ???????????????????????????????????????????????????? ???????????????????????????????????? 100 ????????? ??????????????????????????????????????????????????????????????????????????? ???????? ???????????????????????????????????? >130 ???????? ?????? ??????????? ?????????? ???????????? ????????????????????????????? ?????????????????????? (p