Baselines and Comparison of Coral Reef Fish Assemblages in the Central Red Sea Thesis by Alexander Kattan In Partial Fulfillment of the Requirements For the Degree of Master of Science King Abdullah University of Science and Technology, Thuwal Kingdom of Saudi Arabia December, 2014 2 The thesis of Alexander Kattan is approved by the examination committee. Committee Chairperson: Dr. Michael Lee Berumen Committee Member: Dr. Xabier Irigoien Committee Member: Dr. Simon Thorrold 3 © (December, 2014) Alexander Kattan All Rights Reserved 4 ABSTRACT Baselines and Comparison of Coral Reef Fish Assemblages in the Central Red Sea Alexander Kattan In order to properly assess human impacts and appropriate restoration goals, baselines of pristine conditions on coral reefs are required. In Saudi Arabian waters of the central Red Sea, widespread and heavy fishing pressure has been ongoing for decades. To evaluate this influence, we surveyed the assemblage of offshore reef fishes in both this region as well as those of remote and largely unfished southern Sudan. At comparable latitudes, of similar oceanographic influence, and hosting the same array of species, the offshore reefs of southern Sudan provided an ideal location for comparison. We found that top predators (jacks, large snappers, groupers, and others) dominated the reef fish community biomass in Sudan’s deep south region, resulting in an inverted (top-heavy) biomass pyramid. In contrast, the Red Sea reefs of central Saudi Arabia exhibited the typical bottom-heavy pyramid and show evidence for trophic cascades in the form of mesopredator release. Biomass values from Sudan’s deep south are quite similar to those previously reported in the remote and uninhabited Northwest Hawaiian Islands, northern Line Islands, Pitcairn Islands, and other remote Pacific islands and atolls. The findings of this study suggest that heavy fishing pressure has significantly altered the fish community structure of Saudi Arabian Red Sea reefs. The results point towards the urgent need for enhanced regulation and enforcement of fishing practices in Saudi Arabia while simultaneously making a strong case for protection in the form of marine protected areas in the southern Sudanese Red Sea. 5 ACKNOWLEDGEMENTS I would like to begin by thanking my advisor, Dr. Michael Berumen, who provided the funding, guidance, and support needed to carry out this thesis work. I am also indebted to him for the opportunity he offered to travel to and dive in the incredible Sudanese Red Sea. Without that chance, this project simply would not have been possible. Indeed, I never would have experienced any of this crazy life-changing KAUST rollercoaster if it were not for Mike. He created more opportunities for study and research (both in the lab and field), diving and travel (both domestically and abroad), and networking and collaboration (both in KAUST and with other institutions) over the course of this program than I ever would have imagined, for which I am exceedingly grateful and consider myself very lucky. I owe many thanks to all of the members of the Coral Reef Ecology Lab, who each provided assistance in their own way and made their personal contribution towards my uniquely awesome graduate experience over the past 18 months. Their camaraderie was cornerstone during my KAUST tenure. I owe particular thanks to Maha Khalil and Dr. Julia Spaet, who helped with data handling and preparation for the Sudan expedition, respectively. I would also like to acknowledge May Roberts, my number one dive buddy. May’s incessant enthusiasm and keen eye helped me develop the fish identification skills needed to conduct my surveys. Her baking prowess was also instrumental during the writing and analysis process. I thank Dr. Stein Kaartvedt, Dr. Darren Coker, Dr. Julia 6 Spaet, Maha Khalil, and my committee members, whose comments significantly improved this manuscript. Sincere gratitude is extended to the staff and crew of KAUST’s Coastal and Marine Resources Core Lab (CMOR), who made surveying in Thuwal possible (and safe). I recognize the Dream Divers team, who facilitated my surveys in the Al Lith region. And I owe particular thanks to the staff and crew of the Don Questo liveaboard company. Special recognition goes to Captain Lorenzo (Lory) Segalini for his warm Italian hospitality (and cooking) as well as his enthusiasm for working with scientists and his leadership in the Don Questo’s voluntary contributions towards marine conservation in Sudan. I thank Sara Valla for her efforts in making the Sudanese visa process completely painless. I also want to acknowledge the dive guide Mauritzio Chiarenza, who first introduced me to our “friends” (scalloped hammerhead sharks). Seeing nearly one hundred of these magnificent creatures while narced at 45 meters is not an experience I will soon forget. Finally, I would like to pay tribute to the late Hans Hass, early marine biologist, ingenious diving pioneer, and fearless adventurer. His book Manta (1952) was a particularly great source of inspiration during the course of my fieldwork in Sudan. Hass, you were definitely better than Jacques. 7 TABLE OF CONTENTS EXAMINATION COMMITTEE APPROVAL FORM ..................................................... 2 COPYRIGHT PAGE .......................................................................................................... 3 ABSTRACT ........................................................................................................................ 4 ACKNOWLEDGEMENTS ................................................................................................ 5 TABLE OF CONTENTS .................................................................................................... 7 LIST OF FIGURES ............................................................................................................ 8 LIST OF TABLES ............................................................................................................ 10 SECTION 1 – INTRODUCTION .................................................................................... 11 1.1 – The Anthropocene………………………………………………………….12 1.2 – Human Impacts on the Marine Environment and the Shifting Baseline…..13 1.3 – Pristine Coral Reefs………………………………………………………..16 1.4 – Concept and Justification of the Study…………………………………….17 SECTION 2 – MATERIALS AND METHODS .............................................................. 21 2.1 – Study Sites and Sampling Design………………………………………….21 2.2 – Fish Sampling Methodology……………………………………………….22 2.3 – Data Handling and Statistical Analysis…………………………………….24 SECTION 3 – RESULTS ................................................................................................. 26 3.1 – Recorded Fishes and Species Richness, Evenness, and Diversity…………26 3.2 – Fish Biomass, Abundance, and Average Size……..………………………32 3.3 – Shark Sightings…..…………………………..…………………………….36 3.4 – A Proxy for Fishing Pressure…..…………………………..………………38 SECTION 4 – DISCUSSION ........................................................................................... 39 4.1 – Sudan’s Deep South…………………………………………………..……39 8 4.2 – South Sudan, Al Lith, and Thuwal…………………………………………40 4.3 – Shark Sightings………………………………………...…………………..42 4.4 – Study Limitations and Considerations…………………………….……….43 SECTION 5 – CONCLUSION ......................................................................................... 46 APPENDICES .................................................................................................................. 49 REFERENCES ................................................................................................................. 53 9 LIST OF FIGURES Figure 2.1 - Map of the central Red Sea showing location of the four study regions and reefs: Thuwal (purple circles), Al Lith (green triangles), south Sudan (red diamonds), and the Sudanese deep south (blue circles). Map is super-imposed on a bathymetric map taken from Raitsos et al. (2013)………………………………………………………………………….….22 Figure 3.1 - Biomass of fishes in four major tropic guilds from four study regions in the central Red Sea. Stacked vertical bars represent mean biomass estimated from visual surveys of the length and number of fishes counted in belt transects and calculated using the allometric weight-length formula W=aLb, (see Section 2). Trophic guilds are color- coded (see Table 3.1 for species' guild assignments). Results are grouped by study region (horizontal axis). Error bars represent standard error of mean top predator biomass……..33 Figure 3.2 - Numerical abundance of fishes in four major trophic guilds from four study regions in the central Red Sea. Stacked vertical bars represent mean numerical abundance estimated from visual surveys of fishes recorded in belt transects. Trophic guilds are color-coded (see Table 3.1 for species’ guild assignments). Results are grouped by study region (horizontal axis). Error bars represent standard error of mean fish abundance…..34 Figure 3.3 - Average weight of fishes in four major trophic guilds from four study regions in the central Red Sea. Vertical bars represent mean weight in kilograms estimated from visual surveys of the length and number of fishes counted in belt transects and calculated using the allometric weight-length formula W=aLb, (see Section 2). Trophic guilds are color-coded (see Table 3.1 for species' guild assignments). Results are grouped by study region (horizontal axis). Error bars represent standard error of mean weight for each guild and region………………………………………………………………………..….35