Life history and population maintenance strategies ofCalanoides carinatus(Copepoda: Calanoida) in the southern Benguela ecosystem

Abstract

Analysis of quarterly cross-shelf distribution patterns of juvenile and adult Calanoides carinatus off the Cape Columbine upwelling centre in the southern Benguela ecosystem shows that this copepod has behavioural adaptations which result in clear patterns of inshore-offshore zonation. The combination of differential diel vertical movements of the various stages, seasonal ontogenetic migration and the resultant differential exploitation of cross-shelf advective processes and longshore current regimes play an important role in the maintenance of populations within the coastal upwelling areas of the southern Benguela ecosystem. At lower latitudes, C. carinatus utilizes true diapause in its life-cycle strategy to bridge the 8–10 month period between upwelling seasons. In the Benguela, however, the presence of an inshore active and an offshore resting component enables local C. carinatus populations to maintain a perennial presence. Because of a protracted upwelling season and occasional upwelling in winter, ...