Morphometric Measurements, Gonopod and Gonopores Appearances in Early Sexual Crablet Stage of Scylla paramamosain (Estampador, 1949)
Morphometric Measurements, Gonopod and Gonopores Appearances in Early Sexual Crablet Stage of Scylla paramamosain (Estampador, 1949)
Muhammad Nur Syafaat1,2, Che Zulkifli Che-Ismail3, Adnan Amin-Safwan2, Mohamad N. Azra2, Mohammad Syahnon2, Ambok Bolong Abol-Munafi2 and Mhd Ikhwanuddin2*
ABSTRACT
This study was aimed to describe the morphological appearances of gonopod and gonopores along with the carapace sizes at early crablet stage of mud crab, Scylla paramamosain. Changes in abdominal shape were recorded from instar stage 1 (Crablet 1 or C1) of the crabs for sexual differentiation. In addition, comprehensive measurements of their sizes, appearances and description of forked pleopod and both gonopod and gonopores were also recorded. Experiments were carried out using an optical microscope to facilitate the observation of the crablets’ abdomen along with a digital camera which connected to a laptop to capture the sample images. In this present study, the difference of abdominal flap shape began to appear more clearly at C5 stage using an optical microscope with 8-20x magnifications. Female’s abdominal flap in C5 stages was assumed wider than the male’s abdominal flap and the notch on the side was not as clear as in male. The difference of abdominal flap shape between male and female could be recognized with the naked eye when the carapace width reached ±2 cm (±C9 stage). The existence of gonopod in the Carapace Width (CW) range of 05.01–10.00 mm were still difficult to be detected and the existence of gonopod in this range was assumed still a small bulge at the base inside abdomen flap and as well as for forked pleopod. The gonopod and forked pleopod were detected more clearly in CW >10 mm using an optical microscope with 10-20x magnifications. The data from this study can be used to compare male and female of S. paramamosain in the crablet stage, which are valuable during the early stocking of the juvenile crab in the aquaculture facilities or crab ponds and for its selection breeding program or monosex culture development.
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