Zooplankton in the Canary Current Large Marine Ecosystem

Abstract

Copepod species in the CCLME accounted for 60-95% of the zooplankton abundance being the bulk of the mesozooplankton biomass. Two main groups of copepod species can be identified, representing biogeographical and ecological characteristics: tropical and subtropical species, related to a sub region with a low influence of the upwelling nutrient enriched waters (Cape Verde, Canary Islands and Cape Blanc); and subtropical and luso-boreal species identified along the Northwest Africa coast (Cape Spartel-Cape Blanc) with a strong seasonality of upwelling and coastal nutrient rich waters. A succession from small to medium and large calanoids and gelatinous organisms from the upwelled waters to the ocean is the rule and this pattern is coupled with a switch of the feeding mode of the zooplankters. A phytoplankton-based diet was observed in the inshore upwelling zone whereas a microzooplankton based diet was observed offshore under more oligotrophic conditions. More studies are needed to verify that the patterns observed in zooplankton composition and distribution 30-35 years ago are still valid and that climate change and variability of upwelling strength is neither altering the cycles nor the productivity of the CCLME. Also the zooplankton physiology deserves future work as these organisms live longer than any other plankton and are the food of diel vertical migrants (large zooplankton and micronekton).