eDNA sampling across temporal and spatial gradients provide new insights into white, tiger and bull sharks spatial ecology in eastern Australia

Mr Zach Clark¹, Dr Adam Miller¹, Dr Andrew  Weeks², Dr Craig Sherman¹, Ms Jess Fish¹, Dr Paul Butcher³

¹Deakin University, Warrnambool, Australia, ²EnviroDNA, Melbourne , Australia, ³NSW DPI, Coffs Harbour , Australia

Abstract:

Human-shark interactions are becoming increasingly frequent in northern New South Wales (NSW). This prompted the NSW government to implement the Shark Management Strategy (SMS) in 2015, a program primarily geared towards increasing bather protection from shark interactions while minimising harm to sharks. As part of this program, government scientists, technicians and contractors have adopted a variety of survey methods including the use of SMART drumlines, acoustic and satellite tagging and drones, to monitor the movement patterns of individual sharks and seasonality of shark populations. Building on the success of the SMS program, complementary research activities are needed to assist in refining shark detection and monitoring methods using modern innovative tools. In this presentation, I will present the findings from a current research program involving the development and application of white, tiger and bull shark eDNA assays for detecting and monitoring shark populations in northern NSW. Specifically, this study involved undertaking eDNA analyses using a multispecies TaqMan assay on seawater samples collected weekly from 4 set locations from northern NSW over an 18 month period to characterise spatial and temporal patterns of white, tiger and bull shark presence and absence. This novel dataset has provided new insights into shark spatial ecology, including new information on spatial heterogeneity of habitat use and seasonality of shark species in the region. I discuss the results of this study in the context of future shark management in NSW.

Biography:

Zach is a PhD candidate conducting genetic research on Great White Sharks (Carcharodon carcharias), Zach is working closely with the New South Wales Department of Primary Industries to address key knowledge gaps around the spatial ecology of these sharks and will be using a range of molecular genetic techniques such as eDNA paired with qPCR to improve the accuracy of monitoring and detection of these critical species of sharks and further understand there movement dynamics.