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.

The ever-growing concentration of microplastics in the marine environment is leading to a plethora of questions regarding marine organisms’ present and future health status. In this article, the Mediterranean mussel (Mytilus galloprovincialis), a commercial species distributed worldwide, has been exposed to 21 daily doses of polystyrene microparticles (10 µm) at four different concentrations that are environmentally realistic (control: no microplastics, C1: 0.02 mg/L, C2: 0.2 mg/L, and C3: 2 mg/L). The physical status through the condition index, and damages in DNA integrity in gills, through DNA fragmentation, were determined. Results showed a minor effect on DNA integrity but a worse physical status at higher doses. Results could be interpreted as a decrease in mussel feeding activity/filtration rates when exposed to high microplastic concentrations, thus reducing the direct exposure to microplastics in gills. These effects could be happening currently and/or may happen in the near future, threatening populations inhabiting microplastics-polluted environments.

Microplastics (MPs) are increasing in the marine environment as well as inside marine organisms, having an important effect on biological diversity. The trophic transfer of MPs was demonstrated under laboratory conditions, but this study is based on the analysis of preys found in stomach contents. MPs from Merluccius merluccius individuals caught in the Cantabrian Sea and preys inside their guts (blue whiting, and northern krill inside blue whiting) were analyzed. MPs with different chemical composition occurred inside every hake and their preys, with different damages, from aquatic life hazards with long lasting effects, to allergic skin reactions and respiratory irritation, not only for aquatic species and fishing resources, but also for humans through hake consumption. The similarity of MPs profiles from gills and seawater samples would support seawater as the main source of gill microplastics. The MPs profile of hake GIT was similar to that of hake preys inside. Despite the small sample size, the presence of MPs in all the tissues analyzed of hakes and their preys, together with the evidence of hazard compositions of some of them, highlights the need for policies and actions to reduce plastic and microplastic production and consumption.