Baseline assessment of high-latitude coral reef fish communities in southern Africa

Abstract

The Western Indian Ocean (WIO) is a region where detailed coral reef fish research has been relatively limited. This study constitutes an assessment of the fish communities of seven southern African high-latitude coral reefs. The aim was to provide ichthyological baseline data consisting of species abundance and diversity, and family and trophic composition. Sampling techniques consisted of underwater visual censuses, using SCUBA on reefs at a depth of 12–15 m. A total of 284 species belonging to 50 families was recorded. The fish communities are comprised of 80% Indo-Pacific species and the species diversity was comparable to many other reefs in the WIO region. Six families contributed more than 50% towards the overall community composition: Labridae, Acanthuridae, Chaetodontidae, Lutjanidae, Pomacentridae and Serranidae. Five fish species contributed more than 40% to the overall fish abundance: Chromis dimidiata, C. weberi, Pseudanthias squamipinnis, Parapriacanthus ransonneti and Nemanthias carberryi. Planktivores and invertivores dominated the trophic structure on all reefs. The taxonomic overlap in fish species and functional groups between these reefs and other WIO reefs may be owing to population connectivity and warrants further investigation.