High levels of mislabeling in shark meat – Investigating patterns of species utilization with DNA barcoding in Greek retailers

Abstract

Food authenticity has received an increasing focus due to high profile cases of substitution/mislabeling, with many investigations identifying sales of endangered or prohibited species. At the same time, the European Union (EU) has introduced one of the most progressive sets of legislation in order to promote traceability and protect consumers. This study aims to identify shark species that are sold under the commercial term “Galeos” in Greece (which officially designates Mustelus mustelus, M. punctulatus and M. asterias), using DNA barcoding. A total of 87 samples were collected from fishmongers and markets across four cities. A combination of two mitochondrial genes, the cytochrome c oxidase subunit I (COI) and the 16S ribosomal RNA (16S), were used to analyze samples, and species were identified by reference to genetic databases. The results revealed significant differences in patterns of species utilization between cities and retailers. Across the study an extremely high level of mislabeling was identified (56%). This probably relates to some degree of unintentional misidentification and confusion surrounding the designation in Greece, but highlights how consumers are unprotected from incorrect/misleading labels. Over half of products originated from species that are locally listed as threatened by the ICUN red list, and of the mislabeled products, 23% originated from species with prohibitions on landings or CITES listings. This includes large growing sharks with little resemblance to Mustelus spp. and likely demonstrates deliberate substitution. It shows how mislabeled products are providing a route for prohibited/protected sharks to enter the supply chain and be sold to consumers.