Water-body preferences of dominant calanoid copepod species in the Angola-Benguela frontal zone

Abstract

The distribution of five dominant calanoid copepods was related to different water masses in the Angola-Benguela Front system. Five water bodies were identified by principal component analysis, on the basis of abiotic parameters such as temperature, salinity,
dissolved oxygen, phosphate, silicate, nitrate and nitrite. These parameters were reduced to single factors and arranged along two principal component axes. The copepod species included females and copepodites C5 of Calanoides carinatus and females of Metridia lucens, Centropages brachiatus, Nannocalanus minor and Aetideopsis carinata. The water bodies identified in the frontal system were related to currents, upwelling processes, an oxygen minimum layer and biological modification. The different copepod species, as well as the two ontogenetic stages of C. carinatus, showed clear preference for specific water bodies, and their behavioural and physiological adaptations to the environment are discussed.

Keywords: Angola-Benguela Front, copepods, oxygen minimum layer, principal component analysis, water bodies, zooplankton

African Journal of Marine Science 2005, 27(3): 597–608