Moulting behaviour responses of Bay lobster, Thenus orientalis, to environmental manipulation

Abstract

Bay lobster, Thenus orientalis, locally known as Moreton Bay bug, is being investigated for aquaculture, and controlling the moulting process is critical to success in the production of softshell animals. Identification of moult stages is possible because of the existence of exoskeleton ecdysial sutures (crack lines) on the gill chambers. The timing of moulting is synchronised and occurs around sunset when animals are under a natural day‐night condition. The timing and synchrony of moulting can be manipulated by altering the day‐night cycle, whereas the length of the actual moult stage can be shortened/prolonged by manipulating temperature. During the intermoult stage for juveniles (average weight 79 g), body weight increases only by 9%, whereas the majority of weight gain (an additional 44%) occurs within the short period just before and after the actual moult stage. These findings have application for the development of “softshell” products, which can be harvested at around the actual moult stage.