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

Abstract

Intentional mislabelling of seafood is a widespread problem, particularly with high-value species like 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 Community of Catalonia. To understand the geographic extent of the problem we also sampled Merca-Madrid, Europe’s biggest fish market, and Merca-Málaga for its proximity to the bluefin tuna migratory route and trap fishery. Monthly surveys were carried out over one year. The results showed a high deficiency in labelling: 75% of points of sale and 83% of restaurants did not specify the species, and in those cases the name of the species had to be asked. A total of 375 samples were analysed genetically, the largest dataset gathered in Europe so far. The identified species were Thunnus albacares, Thunnus thynnus and Thunnus obesus. Species substitution began at suppliers, with 40% of observed cases, increasing to 58% 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 observed a decrease of Bluefin tuna substitution and an increase of reverse substitution revealing some 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 deficiency of 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 policy execution, and the urgent need for information campaigns to Spanish consumers.

Complex Dispersal of Adult Yellowfin Tuna From the Main Hawaiian Islands

“…Sampling at each collection site/ area so far has remained small scale (n ≤ 11, Barth et al, 2017;n ≤ 24, Grewe et al, 2015;n ≤ 45, Pecoraro et al, 2018;n ≤ 80, Anderson et al, 2019), and the number of sites in the Pacific are limited (n = 2, Barth et al, 2017;n = 3, Grewe et al, 2015;n = 4, Pecoraro et al, 2018;n = 7, Anderson et al, 2019). Nonetheless, DNA profiling is expected to gain widespread use for its utility in addressing illegal fishing and seafood mislabeling (Gordoa et al, 2017). Given our results that yellowfin are highly mobile over a short period of time, particular attention should be given to DNA sampling design to account for spatiotemporal factors from seasonal movements of multiple size classes, to changing oceanographic conditions (e.g., currents, temperature, monsoon) and coupled systems (e.g., ENSO).…”

Tuna labels matter in Europe: Mislabelling rates in different tuna products

“…The mislabelling rate was not significantly different (Chi-square = 0.1045; df = 1; P = 0.3733) between fresh & frozen and canned tuna, 6.70% and 7.84%, respectively, while the miscellaneous products showed 1.92% mislabelling (not significative differences among them). Previous works have reported higher mislabelling rates, recently Gordoa et al [ 16 ] have shown that fresh and frozen tuna in Spain was mislabelled up to 37% at points of sale, while in restaurants the mislabelling rate was even higher, 48%. In a previous report from Oceana [ 28 ], tuna samples obtained at different points of the value chain in different states of the USA showed that 58% of tuna products were mislabelled.…”

“…These results agree with the results found by Vandamme et al [ 29 ] that reported a low mislabelling rate for tuna in sushi of about 10%, but which rises up to 18% when tuna species is considered in the labelling. Likewise, Gordoa et al [ 16 ] reported a 73% of mislabelling for Atlantic Bluefin tuna and points towards economic gain as the main reason for mislabelling tuna. Atlantic Bluefin mislabelling has been highlighted as an example of inverse relationship between low volume catches and high proportion of substitution; offer and demand do not match and the result is a very high mislabelling rate [ 30 ].…”

“…obesus . This type of substitution has been referred by some authors as reverse substitution, a cheaper species is substituted by an expensive one, and that may be an indication of hiding a product from a IUU fishery practice [ 16 ]. Another substitution was found in Germany where T .…”

“…In general, factors such as country, type of retailer, sampling target or year may explain these differences. Pardo et al [ 15 ] suggest an average 18% misdescription for tuna, Gordoa et al [ 16 ] found 37% of fresh and frozen tuna in Spain at points of sale and 48% in restaurants. In some other cases, these values were extremely high such as 95% found by Oceana in Brussels restaurants for Bluefin tuna [ 17 ]; however, studies have typically varied in their sampling strategies, and therefore remain poorly comparable.…”