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Genetic Tracking Offers Options for Tuna Sustainability

by the Fish Site Editor
27 October 2009, at 12:00am

SPAIN - A new method that uses gene sequencing to accurately distinguish between tuna species has the potential to support fisheries management and possible trade restrictions for endangered tuna species.

The new method, revealed in a paper published today in PLoS ONE, the online open-access scientific journal, can make an identification from any kind of processed tuna tissue.

The true tunas – from the genus Thunnus – are among the most economically valuable fish in the world and are also among the most endangered of all commercially exploited fish.

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 ever a genetic method for the precise identification of all eight recognized species of tuna.

Northern, southern and Pacific bluefin tuna are among the most stressed fish populations in the world, with the Principality of Monaco having lodged an application before the Convention on International Trade in Endangered Species (CITES) for a trade ban on the Atlantic (Northern) Bluefin Tuna where several fisheries have collapsed and failed to recover and the Mediterranean Bluefin fishery is exhibiting advanced signals of impending collapse in the face of overfishing and decades of poor management.

The other tuna species are yellowfin, blackfin, longtail, bigeye and Albacore tuna. Identification of traded forms of the fish, which can be 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.

The analysis of the DNA sequence variability of two unlinked genetic markers, one a hypervariable segment of the mitochondrial genome and the other a nuclear gene, enables full discrimination between all the tuna species.

the Fish Site Editor