Aspects of moulting of the South African West Coast rock lobster, Jasus lalandii

Abstract

Background: The wet coast of southern Africa is subject to coastal upwelling and is characterized by often dense kelp beds that can extend as far as 3 km offshore. Kelp forests create a unique ecosystem. Not only are they extremely productive, and so provide de food for many animals, but they also break the force of the waves to create a sheltered habitat (Branch and Branch 1988). Some of the animals that take advantage of this environment include the commercially important rock lobsters and abalone. The life cycle of spiny lobster is geared to the production of large numbers of eggs and therefore larvae. piny lobstrs are one of the organisms that make use of ocean current systems to transport their phyllosoma larvae, away from the parent populations. These phyllosoma larvae (transparent dor ove generally flattened body) ad o pt a drifting existence among the plankton and moult through thirteen larval stages before they met a morphoe into a swimming stage known as a puerulus. The transparent miniature lobster th en "·ettles in shallow-water kelp beds (nursery grounds) approximately l 8 months later (Pollock 1989). depending on the route taken and current velocities Palinuridae) is fished off the west-south coast. Sexually mature rock lobster moult once a year (Pollock 1986), and moulting of the female is followed by copulation (a male lobster in a hard-shelled condition deposits sperm on the underside of a female which is in a soft-shelled condition) and oviposition Newman and Pollock 1974b). The eggs are thought to be fertilized internally (lib er Bauer 1971) and attach to ovigerous setae on the underside of the abdomen on extrusion. The incubation period lasts between four to six months depending on water temperatures. Peak hatching takes place in October and overnber each year, and this coincides with the onset of upwelling.