Below and beyond the species: DNA tools for geographic traceability analysis of cod products in European markets

DNA technology has been shown as an effective tool to monitor seafood trade and improve transparency. It has highlighted seafood species mislabelling on a global scale and has attracted the interest of policy makers, government authorities, and other stakeholders. Despite the proven success of genetic methods in seafood traceability, studies exploring the mislabelling of geographic catch location within a species remain rare. Accurately disclosing the catch location of wild-caught fish is crucial for sustainable seafood management, but verifying this information remains difficult. Tools to evaluate catch location are on the rise and offer an unprecedented opportunity to expand investigations of seafood mislabelling. Diagnostic Single Nucleotide Polymorphisms (SNPs) have been used extensively in the context of population genetics and have the potential to reveal trends in seafood fraud. In this study, we demonstrate the efficiency of a set of nine diagnostic SNPs for the identification of two heavily harvested cod populations, the Northeast Arctic cod and the North Sea cod, and conduct a market analysis of catch location mislabelling of Atlantic cod sold in four European countries. Our findings suggest that inexpensive, diagnostic molecular tools can effectively monitor mislabeling in catch locations and discuss how the method can be enhanced to minimize errors and maximize utility, towards strengthening governance, enhancing sustainability, and boosting consumer trust. • Genetic tools are not often used to evaluate seafood fraud of geographical catch location. • Atlantic cod is a prime candidate for investigating geographic mislabelling. • Species mislabelling of cod remains low in Europe. • Apparent mislabelling of cod geographical catch location is comparatively high. • There is a need for more accurate seafood labelling and enhanced supply chain transparency.