Conservation of elasmobranch populations is often inhibited by a lack of data, particularly in understudied regions like the Red Sea. Survey efforts in this region have been infrequent and often highly localized. Establishing a broad baseline for elasmobranch diversity and abundance along the Saudi Arabian Red Sea coast could inform both conservation efforts and a nascent ecotourism industry. In this thesis, I describe a pilot study comparing biodiversity data from baited remote underwater video stations (BRUVS), unoccupied aerial vehicle surveys (UAVs), and eDNA sequencing at five islands in the Farasan Banks region of the Saudi Arabian Red Sea. Estimates of relative abundance were also compared between the BRUVS and UAVs. Each method identified species missed by the other two, but all three techniques exhibited clear habitat- and taxa-specific biases. I was able to identify key concerns for each approach that need to be addressed before large-scale implementation. If carefully planned and executed well, a full assessment of the Saudi Arabian coastline could establish a true baseline for shallow water elasmobranchs in the eastern Red Sea. Informing best conservation practices and identifying potential ecological attractions in accordance the environmental and economic goals of Saudi Arabia’s Vision 2030.

Predators often have strong top-down effects on ecosystems and are considered a priority for conservation and management. Predator activity can influence prey distribution, abundance, and foraging behaviors and are likely to influence habitat by impacting ecological and environmental characteristics as well as presence of competitor species. There are knowledge gaps of the functional diversity of fish assemblages, non-consumptive predator effects, and environmental effects on fish assemblages. With this study, effects of top marine predators, such as sharks and great barracuda, on diversity and abundance of prey communities were examined in putative low (north side of South Bimini = lagoon) and high-risk (south side of South Bimini = flat) areas around South Bimini, The Bahamas. Baited remote underwater video surveys (BRUVs) deployed in the nearshore habitat captured abundance and potential predator-prey interactions. Predator and prey abundances at each site were compared to determine potential risk affect within high and low risk environments. A general baseline of predator and prey species was established throughout six months of observation (January- June 2018). Results showed a difference in prey communities between high and low risk habitats. Teleost abundance was highest on the south side of South Bimini. There were no differences in flight behavior of prey from predator (sharks vs barracuda). Longitude, depth, temperature, salinity, and dissolved oxygen were significantly linked to biotic assemblages. The identification of significant factors influencing predator-prey interaction is important in understanding community composition and for future implementation of conservation and management practices pertaining to nearby mangrove and seagrass habitats.

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