Spatio-temporal distribution of mesozooplankton in a sub-Antarctic coastal basin of the Kerguelen Archipelago (southern Indian Ocean)

Seventeen surveys were performed fortnightly from January to December 1990 and covered a grid of 16 stations in the large Morbihan Bay at Kerguelen Island. Temperature and salinity were measured at four or five standard depths. Chlorophyll, carbon and nitrogen contents of surface water particulate matter were determined along with mesozooplanktonic biomass and abundance of copepods. The dominant species (90%) of mesozooplankton wasDrepanopus pectinatus, and two other taxa,Oithona spp. andCalanus simillimus, accounted for 8.6 and 0.4% respectively. A Multiple Correspondence Analysis was used to determine the influence of abiotic (temperature and salinity) and biotic factors (potential food supply) on the spatio-temporal distribution of copepods and, more specifically, on that of the growth stages ofD. pectinatus. No specific hydrological features were found. The distribution of copepods was fairly homogeneous in the whole bay while the quantitative changes were influenced by the seasonal rhythm. Only a slight trend of increasing values for the biotic or abiotic parameters and the neriticD. pectinatus was observed from the central to the inner back area of the bay.