Gene-associated markers can be used to trace individual fish back to their population of origin, suggests research published in Nature Communications this week. This finding may provide a useful tool in the fight against illegal fishing.

Illegal, Unreported and Unregulated (IUU) fishing plays a significant role in the overexploitation of global fish stock. International regulations now require catch certificates that state the origin of fish and fish products traded within the EU. However, ways to independently monitor these certificates are still needed.

Einar Nielsen and colleagues applied gene-associated markers - Single Nucleotide Polymorphisms - to four commercially important marine fish species, including Atlantic cod and herring. They found they could correctly assign 93-100% of the fish to their origin. This method could therefore prove useful and be applied worldwide to trace illegal fishing and to correct mislabelled fish stock.