Summary of Abstract Submission

Abstract Submission No. IO50-08-0025PresentationOral

EPI-PELAGIC BIOGEOGRAPHY OF CALANOID COPEPODS IN THE WESTERN INDIAN OCEAN

Riaan B. Cedras*1, Mark J. Gibbons1

1 University of the Western Cape, South Africa

ABSTRACT :

Published information on the distribution of calanoid copepods from the Western Indian Ocean (WIO) are consolidated and combined with new data collected from the South West Indian Ocean Ridge, in order to generate an updated biogeography for this order of copepods in the region. Eighty-five five degree grid squares were mapped for the WIO. Epi-pelagic biogeographic provinces were identified using the Bray-Curtis similarity indices. Calanoid copepod assemblages were consistent with the major flow of water masses from adjacent provinces. The WIO was delineated into cold- and warm-temperate and subtropical and tropical groupings, within which there were generally strong subgroupings based on latitude and longitude. There was fairly strong support for Longhursts' biogeochemical provinces but differences were noted. It is speculated that the differences between groupings in our analysis might reflect large-scale mixing, poor sampling efforts and a wide distribution of cosmopolitan species amongst neighbouring provinces; however, more data are needed. Differences with Longhursts' provinces are ascribed to differences in sampling effort across the region and to the qualitative nature of the analyses. This pattern is compared with those generated from other taxa