Fraud in highly appreciated fish detected from DNA in Europe may undermine the Development Goal of sustainable fishing in Africa

Abstract

Despite high effort for food traceability to ensure safe and sustainable consumption, mislabeling persists on seafood markets. Determining what drives deliberate fraud is necessary to improve food authenticity and sustainability. In this study, the relationship between consumer’s appreciation and fraudulent mislabeling was assessed through a combination of a survey on consumer’s preferences (N = 1608) and molecular tools applied to fish samples commercialized by European companies. We analyzed 401 samples of fish highly consumed in Europe and worldwide (i.e. tuna, hake, anchovy, and blue whiting) through PCR-amplification and sequencing of a suite of DNA markers. Results revealed low mislabeling rate (1.9%), with a higher mislabeling risk in non-recognizable products and significant mediation of fish price between consumer´s appreciation and mislabeling risk of a species. Furthermore, the use of endangered species (e.g. Thunnus thynnus), tuna juveniles for anchovy, and still not regulated Merluccius polli hake as substitutes, points towards illegal, unreported and/or unregulated fishing from African waters. These findings reveal a worrying intentional fraud that hampers the goal of sustainable seafood production and consumption, and suggest to prioritize control efforts on highly appreciated species.

Best BLAST hit alone cannot be used as evidence of fraud

“…The tree shows two clearly differentiated clades: one is exclusively composed by T. thynnus sequences, while the other includes T. alalunga, T. thynnus "alalunga-like" sequences as well as the sequences from the putatively mislabelled products and their best BLAST hit. These results refute the mislabeling of T. thynnus products as T. alalunga reported by Blanco-Fernandez, et al 1 . and, more importantly, invalidate their impactful interpretations and conclusions derived therein.…”

“…Indeed, it has been estimated that approximately 2-3% of T. thynnus individuals have the so-called "alalunga-like" mitochondrial DNA 7 , which has often misled mitochondrial based phylogenetic inferences of the genus Thunnus 8 . This hypothesis was confirmed by a phylogenetic inference including the putatively mislabelled sequences from Blanco-Fernandez, et al 1 . and their best BLAST hit, as well as representative sequences from T. alalunga, T. thynnus (including those labelled as "alalunga-like") and T. albacares (Figure 1).…”

“…Indeed, BLAST results deeply depend on the completeness and accuracy of the reference databases. For example, Blanco-Fernandez, et al 1 . reported mislabeling between Merluccius polli and M. paradoxus/capensis based on best BLAST hit.…”

Illegal, Unreported, and Unregulated Fisheries Threatening Shark Conservation in African Waters Revealed from High Levels of Shark Mislabelling in Ghana

“…Almerón-Souza et al [ 47 ] also reported high covered exploitation of Prionace glauca (23.8%) and Sphyrna lewini (22.2%) in Southern Brazilian fish markets. On the other hand, although high rates of mislabelling have been identified in various seafood [ 9 , 48 , 49 , 50 , 51 ], there was no mislabelling in the 14 shark samples analysed from northern Spain, regardless of presentation (fillets or whole pieces). Spain has strict labelling regulations for seafood products origin [ 52 ].…”

COIBar-RFLP Molecular Strategy Discriminates Species and Unveils Commercial Frauds in Fishery Products

“…Another incontrovertible fact is that the DNA analysis is the best approach to unveil the illegal practice of species substitution, a fraud difficult to identify in all cases where the morphological identification of the species is impracticable because of food processing (i.e., ready to eat products or frozen fillets). Several molecular marker and methodologies have been proposed to be applied for authentication of species [ 13 ] and the mitochondrial genes (Cytochrome Oxidase I, cytochrome b, control region, 16SrDNA) are the most used molecular markers [ 14 ]. However, while the barcoding methodology based on sequencing of the mitochondrial Cytochrome Oxidase I gene (COI) has become the marker of choice for identifying animal species and fish species in particular [ 15 , 16 ], the other mitochondrial genes and the control region in particular, have been most used for studies of population genetic structure [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ].…”