Distribution, depth use and environmental associations of sharks and rays (Elasmobranchii) in the eastern Red Sea

The Eastern Red Sea is a known biodiversity hotspot encompassing an extensive fringing coral reef ecosystem. However, this region faces alarming relative declines in elasmobranchs (sharks, in particular) populations related to heavy fishing pressure. At the same time there is inadequate data on these species’ distribution, diversity, and ecology. For many species of large shark found in the Red Sea, little information exists on their habitat extent and related environmental drivers, limiting effective conservation strategies. Our study use an expansive dataset (CERSE) to shed light on the vertical distribution of local elasmobranchs, their environmental associations and correlation with abiotic factors. We identify critical habitats and hotspots of elasmobranch abundance in the Eastern Red Sea, pivotal for their preservation and in informing the design of robust conservation measures. We highlight the remarkable ability of certain elasmobranchs to endure prolonged periods of hypoxia, potentially linked to the unique temperature characteristics of the Red Sea.Understanding this relationship may provide valuable insights into the plasticity of certain elasmobranchs and how these adaptations could aid in their survival amid ongoing climate change and the associated decline in oxygen levels. Overall, our data on the elasmobranch population trajectories in the Red Sea region reinforce the alarming declines highlighted by previous studies in this region, emphasizing the critical need to strengthen policy enforcement for their protection. By enhancing conservation efforts in the Eastern Red Sea, we can help ensure the long-term survival and ecological stability of these important species.