In 2020, global wild capture fisheries produced an estimated 90.3 million tonnes of seafood valued at $141 billion USD. Despite this scale, major data gaps remain around exactly which species are being caught and in what quantities—an issue that complicates sustainable fisheries management. Traditionally, monitoring these fisheries has relied on time-intensive methods like logbooks, onboard observers, patrol vessels, and tagging programs. However, Dr Madeline Green from the University of Tasmania’s Institute for Marine and Antarctic Studies (IMAS) has developed an innovative, low-cost solution that could transform this process: DNA fingerprinting of brine water from fishing vessels.

By extracting environmental DNA (eDNA) from the brine water in vessel holding tanks — where fish are stored after being caught — Dr Green and her team can accurately identify almost all species present, even without seeing the fish themselves. This method, akin to forensic analysis, is being refined with support from Oceankind, a US-based philanthropic organisation, and scaled up to support broader implementation.

The potential of this tool is particularly significant for poorly monitored or under-resourced fisheries. For instance, in the Indian Ocean Tuna Fishery, about half of the sharks caught and sold as bycatch cannot currently be identified to species level, which hampers conservation efforts. DNA monitoring could help address this by offering precise data on species composition, aiding in the protection of vulnerable or endangered populations.

While current focus is on species identification, future applications of the technique may include estimating catch volumes. Dr Green emphasises that this tool is particularly well-suited for lower GDP countries where expensive enforcement infrastructure is not feasible, offering a practical and scalable approach to enhance transparency and inform ecosystem-based fishery management.

Ultimately, this technology offers a promising step toward more sustainable global fisheries. As Dr Green notes, “You can’t manage what you don’t know”—and this new method ensures that fishery managers, scientists, and policymakers have the vital information needed to protect marine biodiversity and ensure the future of fish populations.

The full University of Tasmania article is available here: https://www.utas.edu.au/about/news-and-stories/articles/2024/tasmanian-fisheries-forensics-technology-set-to-improve-global-catch-management