Miss Thea Larsen1, Dr Mark Hamann1, Dr Cecilia Villacorta Rath1,2
1James Cook University, Townsville, Australia, 2Centre for Tropical Water and Aquatic Ecosystem Research (TropWATER), Australia
Biography:
Thea grew up in rural Australia and, after gaining experience in eco-tourism through travel and work, decided to pursue a degree in Wildlife Conservation. This path led her to undertake a Master’s degree in Marine Biology at James Cook University in Townsville, Far North Queensland. Her research focuses on marine turtle environmental DNA (eDNA), particularly in developing methodologies and enhancing detectability within coastal habitats.
Abstract:
Environmental DNA (eDNA) is a fast emerging method of detection within the field of wildlife monitoring. It can be a beneficial instrument in identifying a wide variety of species in diverse environments, however there is currently great disparity in the availability of literature on some species. Sea turtles are among an elusive group of marine reptiles that are understudied in the realm of eDNA owing partly to their perceived low shedding rates. In this study we aimed to investigate the detectability of green sea turtles (Chelonia mydas) from coastal environments with turbid waters. First, we determined the best sampling strategy by filtering varying water volumes from a tank housing one green sea turtle with different pore size filter papers (20, 10, 5, 1.2 and 0.2m). DNA extracts were screened for the target species on quantitative PCR (qPCR) using a species-specific probe assay. Results indicated that filtering 10L of water through 10m filters constituted the best approach for capturing eDNA from turbid environments. Subsequently, water samples were collected from areas with a gradient of green sea turtle abundance following the optimised sampling method, including a “positive control” site. Sites were sampled more than once, where possible, to test replicability of the results. Occupancy models were used to determine if there was a correlation between turtle abundance and eDNA detectability. The findings of this study have the capability to aid in providing a non-invasive detection method for elusive marine reptiles in turbid waters.