Diversity and abundance of wrasse species in the Gulf of Aqaba

Abstract

The diversity, distribution and abundance of wrasse fishes of the family Labridae were analysed along the Egyptian Red Sea coast in the southern Gulf of Aqaba. Different sites around Dahab (South Sinai Peninsula) were investigated at 4 depth levels from reef flat to reef slope and fore reef. A total of 37 species from 19 genera were recorded, and evenness and diversity indices, frequency, absolute and relative abundances of the species were calculated. A total of 10 more species were observed outside sampled transects resulting in a total diversity of 47 wrasse species for the region. The Gulf of Aqaba thus harbours a higher wrasse species richness than previously reported. The spatial heterogeneity of wrasses was influenced by the reef zonation, substrate composition and habitat structure. The average number of species was highest on the reef slope, while wrasse density was highest on the reef flat due to the schooling of some smaller species and aggregations of juveniles. Many wrasse species showed a clear zonation preference in their distribution and occurred in limited habitats, while others were documented in all areas and depth levels. Environmental influences have a major impact on the species composition in coral reefs. Some factors were evaluated for their importance on the wrasse diversity in the Gulf of Aqaba. Temperature and photoperiod-dependent reproductive cycles have been identified for most species. All studied reefs showed high wrasse diversity, which was (among other factors) influenced by tourist activities (e.g. SCUBA diving) in the area.