Low diversity and abundance of predatory fishes in a peripheral coral reef ecosystem

• Published in: Ecology and evolution Vol. 14; no. 2; pp. e10920 - n/a
• Main Authors: Williams, Collin T., Garzon, Francesco, Cochran, Jesse E. M., Tanabe, Lyndsey K., Hawkes, Lucy A., McIvor, Ashlie J., Eweida, Ameer A., Marshall, Paul A., Berumen, Michael L.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.02.2024; Wiley
• Subjects: Abundance; Basins; Biogeography; Coastal development; Coral reef ecosystems; Coral reef habitats; Coral reefs; Environmental factors; Fish; Fisheries; Fishing; Gulf of Aqaba; Habitats; marginal seas; Marine fish; Multivariate analysis; Ocean basins; Overexploitation; Predators; Recovery plans; Red Sea; Reef fish; Relative abundance; sharks; Software; Taxa; Threatened species; Red Sea; Gulf of Aqaba; Red Sea; Gulf of Aqaba; fisheries; sharks; marginal seas; biogeography
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.10920

Semi‐enclosed seas are often associated with elevated local threats and distinct biogeographic patterns among marine fishes, but our understanding of how fish assemblage dynamics vary in relation to relatively small semi‐enclosed seas (e.g., the Gulf of Aqaba) remains limited. Baited remote underwater video surveys (n = 111) were conducted across ~300 km of coral reef habitats in the Gulf of Aqaba and the northern Red Sea. A total of 55 predatory fish species were detected, with less than half of all species (n = 23) observed in both basins. Relative abundance patterns between the Gulf of Aqaba and the northern Red Sea were variable among taxa, but nearly twice as many predatory fish were observed per unit of effort in the northern Red Sea. In general, assemblages in both basins were dominated by three taxa (Epinephelinae, Carangidae, and Lethrinidae). Large‐bodied and threatened species were recorded at very low abundances. Multivariate analysis revealed distinct assemblage structuring of coral reef predators between the Gulf of Aqaba and the northern Red Sea. Most of the species driving these differences were recorded in both basins, but occurred at varying levels of abundance. Environmental factors were largely unsuccessful in explaining variation in assemblage structuring. These findings indicate that biological assemblages in the Gulf of Aqaba are more distinct than previously reported and that reef fish assemblage structuring can occur even within a relatively small semi‐enclosed sea. Despite inter‐basin assemblage structuring, the overall low abundance of vulnerable fish species is suggestive of overexploitation in both the Gulf of Aqaba and the northern Red Sea of Saudi Arabia. As the region surveyed is currently undergoing large‐scale coastal development, the results presented herein aim to guide spatial management and recovery plans for these coral reef systems in relation to this development. Our findings provide insights into the structuring of coral reef fish communities, demonstrating that distinct assemblages can occur within semi‐enclosed seas at smaller spatial scales than previously documented. We also report a low abundance of threatened fish species in an area of rapid, large‐scale coastal development, which identifies an urgent need to develop a regional management plan.