Moulting stages in orange mud crab Scylla olivacea
Ghazali, A., Fazhan, H.,, Ikhwanuddin, M., Achdiat, M., Rusydi, R., and Waiho, K.

Higher Institution Center of Excellent (HICoE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu.

Abstract

Aquaculture is one of the fastest growing food production sectors in the world and plays a major role in global food security, including Malaysia. Mud crabs genus Scylla are among the commercially important seafood product in Malaysia with increasing demand from both domestic and international markets. However, among the major problems in juvenile crab culture and the production of soft-shell crab are the unsynchronised moulting that would lead to high cannibalism rate. Information on the detailed characterisation of the molting proces is limited and not elaborated in details in mud crab genus Scylla. Determination of the moulting stage in mud crab is important in the effort to synchronise the moulting process. Therefore, the present study was designed to identify and characterise in details the moulting stages in mud crab genus Scylla, via setal morphology and the epidermal retraction. Based on both characters, four moulting stages in orange mud crab, S. olivacea were determined and classified as Intermoult, Premoult (early and late premoult), Ecdysis and Postmoult. This study will be the first to provide a simple and practical method in determining the moulting stage (especially the premoult stage), where it is hope to serve as an essential baseline information in improving the aquaculture and fisheries management in general.

Keywords: Mud crab, Scylla olivacea, moulting stages, softshell.

Topic: Sustainable Aquaculture and Fisheries