Dr Alyssa M. Budd1,2, AProf Tom Schils3, Dr Madalyn K Cooper1,2, Dr Mitchell B Lyons4,5, Mr Matthew S Mills3,6, Ms. Mari E Deinhart3, Dr Agnès Le Port1,7, Dr Roger Huerlimann1,2,8, Prof Jan M Strugnell1,2,9
1Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, Australia, 22 Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, Townsville, Australia, 3Marine Laboratory, University of Guam, Mangila, USA, 4Remote Sensing Research Centre, School of Earth and Environmental Sciences, University of Queensland, Brisbane, Australia, 5School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia, 6 School of Science, Technology, and Engineering, University of the Sunshine Coast, Sippy Downs, Australia, 7 Australian Institute of Marine Science, Townsville, Australia, 8Marine Climate Change Unit, Okinawa Institute of Science and Technology, Onna-son, Japan, 9Department of Ecology, Environment and Evolution, School of Life Sciences, La Trobe University, Melbourne, Australia
Scalloped hammerheads (Sphyrna lewini) have undergone a steep population decline worldwide, leading to a ‘critically endangered’ classification. There is urgent need for data on the distribution of S. lewini to inform the design and implementation of conservation management strategies. In a collaborative project between the United States Department of Navy, the University of Guam, and James Cook University, we developed and optimised a probe-based qPCR assay for the detection of S. lewini environmental DNA (eDNA). The assay underwent thorough laboratory and field validation, and was then applied to a 1.5 year long eDNA spatial survey in Apra Harbor, Guam. This resulted in the first scientific detection of scalloped hammerhead sharks in Guam in 50 years. Furthermore, we provide previously unavailable information on the spatial and temporal presence of this S. lewini population in Guam. Combining eDNA survey results with ecological data indicated that S. lewini eDNA detections were most frequent at sampling sites characterised by attributes associated with protection from predators, including high turbidity, shallow depths, and large distances from the harbour entrance. This information on the local distribution and habitat preferences can now be used to establish management protocols that aim to minimise negative anthropogenic impacts on S. lewini in the harbour, and in enabling compliance with existing protective legislation. Lastly, the survey methods are highly adaptable and can be applied to other areas of historical or contemporary presence to better our understanding of the species’ spatial and temporal distribution.
Biography: