Standard Talk (15 mins) Australian Society for Fish Biology Conference 2022

Using environmental DNA to reconstruct target and by-product catch composition for fisheries vessels (#116)

Madeline Green 1 , Denise Hardesty 1 , Pascal Craw 1 , Bruce Deagle 1 , Chris Wilcox 1
  1. CSIRO, Hobart, TAS, Australia

Fisheries are an important source of food, income and cultural connection for millions worldwide. The pressure from fishing activity can have detrimental impacts on marine ecosystems and coastal livelihoods if not properly managed. Establishing appropriate management measures relies on understanding specific aspects of the fishery, for example what species were caught and recorded in logbooks. There are a wide range of reasons for wanting to reconstruct catch data from fishery independent data. Logbook records may be unavailable or inaccurately report landed species and biomass. Vessel operators or crew may take unregulated or prohibited species, either for sale or for personal consumption. Policy makers during international conventions (CMS, CITES) may make significant binding decisions and treaties with incomplete data. Unfortunately, trained observers who collect crucial independent data onboard vessels cover only a small percentage of total fishing activity. This leaves a significant opportunity for Illegal, Unreported and Unregulated (IUU) fishing practises, the likes of which pose a risk for the management and protection of vulnerable species.

This presentation will introduce a novel eDNA method for forensically reconstructing catch stored in the brine tanks of commercial fishing vessels. Our method allows for a small volume of water to be collected, sequenced and analysed to identify species and rank order abundance. The eDNA collected on-board fishing vessels represents animals that have been in the hold since it was last emptied, providing a time-integrated record of species catch and transport. We propose the application of our eDNA sampling protocol is a cost-effective tool for monitoring and surveillance, particularly for protected or quota species and in under-resourced regions.