DIAPAUSE IN THE LIFE-CYCLE OF CALANOIDES CARINATUS (KROYER), (COPEPODA, CALANOIDA)

The distribution and stage composition of Calanoides carinatus (Kroyer ) are described together with changes in protein and lipid content, re spiration rate and gonad development in copepodite stages IV and V (CV ) and adults in the Northern Benguela current (17 degrees S, 23 degree s S and 25 degrees S). During active upwelling the population consiste d of two parts: the surface part over the shelf was represented by all developmental stages, while the deep part offshore was dominated (90- 95%) by diapausal CVs. In the surface CVs the surplus assimilated ener gy was allocated to structural growth and maturation or to synthesis o f reserve lipids. CVs with large oil sacs and high lipid content desce nded into deeper layers and formed diapausal stock; they were characte rized by a dramatic decrease of respiration rate. Increase of gonad si ze in association with decrease of oil sac volume in diapausal CV sugg ests that reserve lipids were expended not only for respiration but al so for gonad development. The moulting of diapausal CVs into adults to ok place in deep water. These results are discussed in relation to the life cycle of the C. carinatus population and the factors causing the formation and termination of the diapausal phase.