Can eDNA detect cryptic populations of critically-endangered sea snakes?

Dr Jenna Crowe-riddell¹, Dr Vinay Udyawer, Dr Kate Sanders

¹La Trobe University, Bundoora, Australia

Abstract:

Western Australia is a global hotspot for sea snake diversity harbouring six endemics including the Critically-Endangered short-nosed and leaf-scaled sea snakes. Both species were thought to have gone extinct during rapid population crashes at offshore Ashmore/Hibernia Reefs, until they were rediscovered in coastal WA in 2015. Historic museum records and new ecological modelling suggest these vulnerable species’ are found in unexplored regions of Exmouth Gulf, and Barrow and Montebello islands. eDNA presents an unprecedented opportunity to passively monitor populations and discover cryptic populations of vulnerable species. However, there are many challenges to overcome before eDNA can become a reliable tool for monitoring marine reptiles. Two major issues are: 1) the lower cell shedding rate of reptiles (cf. fish), which is thought to reduce the total eDNA that can be detected, and 2) how to adequately sample the fragmented distribution of sea snakes within marine habitats. To improve eDNA detection of sea snakes, we aim to develop an eDNA protocol using a metabarcoding method on water collected from enclosed habitats within Exmouth Gulf, with the view of expanding to open water habitats along the coastline. To understand cell-shedding rate in marine reptiles, we aim to quantify the concentration of eDNA in water collected from sea snakes in captivity using quantitative PCR. These complementary eDNA methods will have a range of applications for the management of an important bioindicator group globally, as well as provide insights into the specific challenges of using eDNA to detect marine reptiles.

Biography:

Jenna completed her PhD in the evolution of senses in sea snakes at the University of Adelaide in 2019. She is currently a postdoctoral researcher at La Trobe University. She hopes to use eDNA as a tool for monitoring and detecting vulnerable populations of sea snakes, which can provide valuable information for the conservation of critically-endangered species.