Carbon and nitrogen losses through moulting in the Cape rock lobster Jasus lalandii

Abstract

Moulting data were collected from a size range of J. lalandii in an aquarium where field conditions of light intensity and temperature were simulated. Elemental analysis was carried out on intermoult exoskeleton, exuviae and whole lobsters. Lobsters lose a mean of 27% of their dry mass per year at ecdysis. Exuviae contained a higher ash content, a 28,1 % lower organic carbon content indicating reabsorption, and a similar inorganic carbon content when compared with intermoult exoskeleton. Estimates for a lobster population occupying 100 m² at Robben Island are that 228 g organic carbon and 57,3 g nitrogen are lost annually. However, the annual cost of moulting to J. lalandii in terms of exuvial mass, which includes carbon and nitrogen, is considerable when viewed in terms of lost production.