Diversity of two groups of reef fish (butterfly fishes and angel fishes) assemblages was investigated around Zabargad Island, Red Sea. Zabargad Island (St. John's Island) is on the border of northern central part in the remote south of Egypt, 70 km off the coast. The island is almost 300 m above the sea level. Four sites were investigated around the Island. Underwater visual census techniques had been used to record fish abundances on reefs. Species richness was expressed by considering the number of species (D) and species diversity. Homogeneity were determined using the Shannon-Wiener diversity index (H') and the evenness index (J'). The total number of butterflyfish species recorded, at different sites, was 10 species belonging to two genera. There are two obvious patterns of distribution of butterfly fishes with depth around Zabargad Island. The highest average abundance was also recorded at site 1 (22 fish/600 m3), with the lowest value at site 2 (10 fish/600 m3). The total number of angelfish species recorded, at different sites, was 7 species belonging to five genera. All angelfish species are not found on the reef flat (except Pygoplites diacanthus and Centropyge multispinis) but they preferred the reef slope and increasing with depths. Substrate composition was calculated as percentage cover for all taxa. Several hard and soft coral genera were recorded from the study sites. On the reef flat, dead components, soft corals and marine plants (especially algae) were dominated, which represented by 42.83%, 31.38%, and 12.25%, respectively. On the reef wall or slope, hard corals, dead components and soft coral were dominated, and represented by 47.55%, 23.83%, and 16.70%, respectively. Linear regression equations were calculated to investigate the relationships between fish community and benthic composition of the substrate.
Key words: Abundance, diversity, coral reef fishes, Zabargad Island, Red Sea
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