Dr Meaghan Duncan1, Dr Matt K Broadhurst2,3, Dr Joseph D DiBattista4,5, Dr D Stewart Fielder6, Dr Ashley M Fowler7, Dr Elise M Furlan8,9, Dr Julian M Hughes7
1NSW DPIRD Fisheries, Narrandera Fisheries Centre, Narrandera, NSW, Australia, Narrandera, Australia, 2NSW DPIRD, Fisheries Conservation Technology Unit, National Marine Science Centre, Southern Cross University , Coffs Harbour, Australia, 3Marine and Estuarine Ecology Unit, School of Biological Sciences, University of QLD, Brisbane, Australia, 4School of Environment and Science, Griffith University, Southport, Australia, 5Australian Museum Research Institute, Australian Museum, Sydney, Australia, 6NSW DPIRD, Port Stephens Fisheries Institute, Nelson Bay, Australia, 7NSW DPIRD, Sydney Institute of Marine Science, Mosman, Australia, 8Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Bruce, Australia, 9Nature DNA, Port Macquarie, Australia
Biography:
Dr Meaghan Duncan is a Senior Research Scientist with the NSW Department of Primary Industries and Regional Development specialising in the application of environmental DNA (eDNA) to fisheries management and aquatic conservation. Her work focuses on developing and applying eDNA tools to detect threatened and invasive species, monitor fish communities, and support environmental management. She played a key role in establishing NSW DPIRD's first dedicated eDNA laboratory, helping build the capability needed for monitoring programs. Her research on the relationship between eDNA concentration and biomass has advanced understanding of how eDNA may be used for biomass estimation and stock assessment.
Abstract:
Australia's commercial and recreational fisheries are collectively worth billions of dollars annually, yet many stocks lack the data required for robust assessments. Traditional fishery-independent monitoring methods can be costly, labour-intensive and difficult to implement across large spatial scales. Environmental DNA (eDNA) has emerged as a promising non-invasive alternative, with growing international evidence suggesting that eDNA concentrations may provide an index of species biomass or abundance. This project investigated whether environmental DNA (eDNA) concentrations were correlated with the relative biomass of four ecologically and economically important Australian fish species: Murray cod (Maccullochella peelii), golden perch (Macquaria ambigua), mulloway (Argyrosomus japonicus) and bony bream (Nematalosa erebi). Species-specific eDNA assays were developed and validated before a several controlled aquaria experiments and field trials were conducted. Aquaria trials examined the effects of biomass, water temperature, time and individual shedding rates on eDNA concentrations, while field trials compared eDNA concentrations with relative biomass estimates derived from electrofishing and hydroacoustic surveys. The results demonstrated positive relationships between eDNA concentration and relative biomass for mulloway and golden perch under controlled conditions, but not Murray cod, possibly due to substantial variability in individual DNA shedding rates. Field trials revealed significant positive relationships between eDNA concentration and relative biomass for all four species, although the strength of these relationships differed inter-specifically and were influenced by factors such as season and flow. These findings support using eDNA as a non-lethal, fishery-independent tool for helping to monitor relative biomass, while highlighting the need for further calibration and validation across environmental conditions.