Mesozooplankton in the Canary Current System: The coastal–ocean transition zone

The Canary Current System (CCS) is one of the largest upwelling areas of the world. Understanding the biogeochemical fluxes and recruitment of fish in relation to changes in climate requires knowledge of the factors influencing mesozooplankton biomass and fluxes. Here, the trophic and metabolic characteristics of mesozooplankton for the oceanic, upwelling and eddy system of the CCS are reviewed. Mesoscale phenomena are of importance in this region as besides upwelling filaments, the eddy system shed from the Canary Islands is unique in comparison with other similar systems such as the Humboldt, California and Benguela. The coupling of production in the coastal area off Northwest Africa with the oceanic zone through filaments and eddies topographically formed in the coast or shed by the islands promotes a continuous transport of organic matter towards the deep ocean. Zooplankton follow the signal of the mesoscale phenomena and are good tracers of advection. The different species, which can be used as targets in the area, are also described from the upwelling region to the open ocean. However, not all the variability in the area is explained by bottom-up controls. The effect of diel vertical migrants feeding on epipelagic zooplankton shows that top-down controls are also important to understanding the structure and fluxes in this oceanic environment.