DUGi

Tuna Species Substitution in the Spanish Commercial Chain: A Knock-On Effect

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Intentional mislabelling of seafood is a widespread problem, particularly with high-value specieslike tuna. In this study we examine tuna mislabelling, deliberate species substitution,types of substitution and its impact on prices. The survey covered the commercial chain,from Merca-Barna to fishmongers and restaurants in the Spanish Autonomous Communityof Catalonia. To understand the geographic extent of the problem we also sampled Merca-Madrid, Europe’s biggest fish market, and Merca-MaÂlaga for its proximity to the bluefin tunamigratory route and trap fishery. Monthly surveys were carried out over one year. Theresults showed a high deficiency in labelling: 75% of points of sale and 83% of restaurantsdid not specify the species, and in those cases the name of the species had to be asked. Atotal of 375 samples were analysed genetically, the largest dataset gathered in Europe sofar. The identified species were Thunnus albacares, Thunnus thynnus and Thunnus obesus.Species substitution began at suppliers, with 40% of observed cases, increasing to58% at fishmongers and 62% at restaurants. The substitution was mainly on bluefin tuna (T.thynnus), 73% of cases. At restaurants, only during the bluefin fishing season, we observeda decrease of Bluefin tuna substitution and an increase of reverse substitution revealingsome illegal fishing. The effect of species substitution on species prices was relevant: T.obesus increased its price by around €12 kg-1 when it was sold as bluefin. In view of the deficiencyof labelling, the abuse of generic names and the lack of the bluefin catch document,we conclude that the Spanish regulations are ineffective, highlighting the need for policyexecution, and the urgent need for information campaigns to Spanish consumers

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