Dr Madeline Green1, Mr Alexander Coutts1
1Institute for Marine and Antarctic Studies, University of Tasmania, Taroona, Australia
Biography:
Alex is a research assistant at the Institute for Marine and Antarctic Science at The University of Tasmania. While working at UTAS, he has applied eDNA to environmental monitoring of aquaculture, the ecological effects of artificial oxygenation, and most recently, fisheries monitoring. He also loves the wonderful world of temperate seaweeds.
Abstract:
Fisheries are a vital resource which contribute to the global economy and food production. To mitigate detrimental ecosystem effects caused by fishing and subsequent economic damage, a range of Monitoring, Control and Surveillance methods (MCS) are commonly used to manage fisheries. One goal of MCS is to understand the number and species of fish being caught as well as where and when they are being caught. Traditionally, catch data is collected in the form of logbooks filled out by onboard observers, or vessel operators and crew, however these methods can provide inaccurate data, partly due to misreporting of illegal fishing activity. As a result, the use of eDNA metabarcoding to collect catch data from samples taken on board fishing vessels has recently been tested as a fisheries-independent data source. While eDNA methods have been effective at reconstructing logbook catch data, the identification of closely related species, including tuna in the genus Thunnus, remains a significant challenge due to high similarity in commonly targeted short mitochondrial DNA (mtDNA) fragments. To address this challenge, we tested long read (1-2 kb) eDNA metabarcoding on 24 water samples from brine tank holds on board tuna longline vessels in Mooloolaba, Australia using Oxford Nanopore Technology sequencing. We targeted mtDNA regions with high variability between Thunnus species. The ability to reconstruct fisheries catch data with high species resolution will allow reliable and efficient collection of data to inform targeted management of Thunnus species which each have unique requirements to ensure sustainability of the fisheries.