In order to assess human impacts and develop rational restoration goals for corals reefs, baseline estimates of fish communities are required. In Saudi Arabian waters of the Red Sea, widespread unregulated fishing is thought to have been ongoing for decades, but there is little direct evidence of the impact on reef communities. To contextualize this human influence, reef-associated fish assemblages on offshore reefs in Saudi Arabia and Sudan in the central Red Sea were investigated. These reefs have comparable benthic environments, experience similar oceanographic influences, and are separated by less than 300 km, offering an ideal comparison for identifying potential anthropogenic impacts such as fishing pressure. This is the first study to assess reef fish biomass in both these regions, providing important baselines estimates. We found that biomass of top predators on offshore Sudanese reefs was on average almost three times that measured on comparable reefs in Saudi Arabia. Biomass values from some of the most remote reefs surveyed in Sudan’s far southern region even approach those previously reported in the Northwestern Hawaiian Islands, northern Line Islands, Pitcairn Islands, and other isolated Pacific islands and atolls. The findings suggest that fishing pressure has significantly altered the fish community structure of Saudi Arabian Red Sea reefs, most conspicuously in the form of top predator removal. The results point towards the urgent need for enhanced regulation and enforcement of fishing practices in Saudi Arabia, while making a strong case for protection in the form of no-take marine protected areas to maintain preservation of the relatively intact southern Sudanese Red Sea.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors thank MT Khalil and JEM Cochran for providing data management templates and the crucial a/b value database; MB Roberts and members of the KAUST Reef Ecology Lab for assistance in the field; the staff and crew of Dream Divers and Don Questo for facilitating sampling in Saudi Arabia and Sudan, respectively; and JLY Spaet and MT Khalil for their helpful conversations, their passion for conservation, and their comments on previous drafts of this manuscript. This work was supported by KAUST (baseline funding to MLB).