Comparative assessment of eDNA metabarcoding and longline deployments for elasmobranch surveying in the Kimberley Marine Park, Western Australia

Dr Katrina West1,2, Dr Alastair Harry3, Sam Payet3, Prof. Euan Harvey2, Michelle Glover4, Jennifer Hoy4, Dr Michael Travers3

1CSIRO Australian National Fish Collection, National Research Collections Australia, CSIRO, Hobart, Australia, 2Trace and Environmental DNA (TrEnD) Laboratory, School of Molecular and Life Sciences, Curtin University, Bentley, Australia, 3Western Australian Fisheries and Marine Research Laboratories, Department of Primary Industries and Regional Development, Government of Western Australia, North Beach, Australia, 4Department of Agriculture, Water and the Environment, Australian Government, Canberra, Australia

Abstract:

The Kimberley Marine Park spans a 74,469 km2 area off the coast of north Western Australia and represents a biologically important refuge for marine megafauna, notably humpback whales, dolphins, dugongs, and turtles, amidst extensive coral communities. Despite this, there is very little information available on demersal shark diversity and population estimates across this vast marine park. In this study, we directly compared the efficacy of eDNA metabarcoding and conventional longline deployments to survey demersal and pelagic elasmobranchs in the Kimberley Marine Park and more broadly. Seawater samples were collected for eDNA screening within 12 hours post-longline deployment at 36 sites across a 55,000 square-kilometre area. In total, we recovered 48 elasmobranch species, 36 of which were detected by eDNA and 30 (from a total of 817 captured sharks) by longline; a combined approach yielding over 33% more elasmobranch species than either approach alone. Site community compositions notably varied between the two survey approaches, but also from broader environmental influences, such as depth, habitat, and latitude. We additionally investigate whether eDNA metabarcoding read abundance data correlates with longline aggregate catch data and assess required levels of eDNA replication and longline deployments to maximise captured elasmobranch diversity, whilst minimising longline fatalities. This study sets an integrated baseline and long-term monitoring approach for the management and conservation of elasmobranch diversity within this unique marine park.


Biography:

Katrina is an early career researcher; she has recently completed her PhD at Curtin University, Western Australia where she focused on the development and application of eDNA metabarcoding for aquatic biomonitoring in Australia’s Indian Ocean region. She is now a postdoctoral fellow at the CSIRO, Hobart where she aims to extend eDNA metabarcoding capabilities and applications for marine fish and elasmobranch monitoring.

Date

Mar 21 - 23 2022
Expired!