RELATIONSHIPS BETWEEN CORAL-REEF SUBSTRATA AND FISH

The objective of this work is to identify which substrata characterist ics (such as coral morphology, coral diversity, coral species richness , percentage coverage by live coral or by algae) influence the structu re and abundance of fish communities. The study was carried out at Reu nion Island, Indian Ocean, where six sites were sampled in two zones ( reef flat and outer reef slope). Quantitative data were collected by v isual census techniques, along a linear transect of 50 m for the subst ratum, and a belt of 50 x 2 m for the fish communities. Correspondence analysis (CA) and an optimising cluster analysis, called dynamic clus tering method (DCM) were used to describe and compare fish assemblages with the benthic composition. The relationships between benthic and f ish communities were examined using the classes revealed by the partit ioning of the substratum with DCM. This partitioning allowed us to der ive four classes of substratum: the non-disturbed reef flat, the non-d isturbed outer reef slope, the perturbed reef habitat and the reef pas s. The analysis of the partitioning based on the coral variables sugge sts that there are significant relationships between benthic and fish assemblages.