A paper published on Tuesday in the online scientific journal PLoS ONE unveils a new genetic methodology that can fully distinguish between all eight tuna species using any kind of processed tissue.
The paper, “A Validated Methodology for Genetic Identification of Tuna Species (Genus Thunnus),” co-authored by Dr. Jordi Viñas, a fish genetics specialist at Girona University in Spain and Dr. Sergi Tudela, head of Fisheries of WWF Mediterranean, proposes for the first time a genetic method for the precise identification of all eight species of tuna.
The analysis of the DNA sequence variability of two unlinked genetic markets — one a hypervariable segment of the mitochondrial genome and the other a nuclear gene — enables full discrimination between the species.
Identification of these species — which are typically dressed, gilled and gutted, or loin and belly meat, and either fresh or frozen — is a highly complex process, which may hamper conservation efforts on trade controls.
“This methodology will allow the identification of tuna species of any kind of tissue or type or presentation, including sushi and sashimi,” said Viñas. “The differentiation between different tunas, even those with highly similar genes, is now possible.”
“Our findings are particularly relevant for … Atlantic bluefin,” said Tudela. “There will now be no trace of doubt when seeking to identify chilled or frozen tuna flesh at port or point of sale.”
Monaco has submitted a proposal to CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) that would ban international trade of bluefin tuna.
