Mercury (Hg) is a pervasive environmental contaminant with high bioavailability and toxicity, accumulating in aquatic food chains and posing significant risks to human health through seafood consumption. This systematic review aims to collect evidence on Hg bioaccumulation in seafood across Europe, assessing species that exceed legal limits. A total of 74 studies were identified on bioaccumulation among marine fish and seafood from European and adjacent seas, published between 2000 and 2024. Findings highlight that methylmercury (MeHg) constitutes the majority of total Hg in fish species, with concentrations often exceeding EU regulatory limits, especially in the Adriatic and Iberian areas. In general, teleosts exhibit higher tissue concentrations of both MeHg and total Hg compared to either selachians or mollusks. Species likely to exceed their legal limits are larger, apex predators, e.g., tuna, swordfish, and sharks, as well as benthic species, e.g., monkfish and mullet. In recent years, there has been a decrease in mercury contamination, probably due to agreed international regulations. However, significant regional variations still persist in Europe. To mitigate Hg contamination in seafood and ensure food safety, this study highlights the need for ongoing monitoring and management strategies, the interplay of environmental factors, food web dynamics, and species-specific biological characteristics.

The present study was designed to assess the influence of fishmeal replacement with increasing percentages of fresh seafood discards (0, 25, 50 and 75%) in diets for Penaeus japonicus on growth performance, physical characteristics and the chemical and fatty acid composition of shrimp flesh. Each diet was administered for 108 days, and the trial was assayed in triplicate. The final body weight and the specific growth rate were significantly higher (p < 0.05) in shrimps fed with 75% fishmeal replacement as compared to 25%, while the abdomen weight and the total length were the highest (p < 0.01). Moreover, 75% replacement showed a significantly (p < 0.05) lower value of hardness and a greater crude protein and lipid content as compared to the 0% replacement. The shrimps fed with high levels of seafood discards (50 and 75%) showed a lower saturated fatty acid concentration and, in turn, a greater amount of polyunsaturated fatty acids in shrimp meat significantly (p < 0.05) affected the lower atherogenic and thrombogenic indices. In conclusion, replacing 75% of fishmeal with seafood discards provided satisfactory results. An economic analysis based on ESG indicators and PESTLE methodology is provided in order to show the socio-economic and governance impacts affecting the replacement of shrimps’ diet with fish discard.

The increasing world market demand for seafood requires an expansion of product categories available to consumers. Inland fish are usually considered having unmarked taste and are less appreciated by consumers; thus, they have low commercial value. Therefore, the marketing of the lake’s fresh and processed fish is limited to the local market and consumers are currently uninformed and mistrustful about these species. In this study, six different fish species were caught in the Fondi lake (Lazio, central Italy): Anguilla anguilla, Tinca tinca, Carassius gibelio, Cyprinus carpio, Micropterus salmoides, Chelon ramada. All the samples were subjected to nutritional and DNA barcoding analysis. Moisture, protein, fat, carbohydrates, ash, and sodium content were measured. As regards the fatty acids profile, the most abundant were MUFAs with the highest value in Anguilla anguilla (45.97%). Oleic acid (C18: 1 n9 cis) was particularly high in Cyprinus carpio (55.46%). The fraction of polyunsaturated fatty acids (PUFA) revealed a higher DHA content (C22: 6 n3) in Anguilla anguilla than the other species (>12 %) while Chelon ramada presented both higher EPA content (C 20: 5 n3) and total fraction of omega 3 PUFAs. Concerning molecular analysis, a 655 bp fragment of cytochrome C oxidase subunit I (COI) gene was successfully used for the identification at the species level using both BOLD and BLAST public databases. The present study gives the basis for improving the knowledge and promoting inland fish’ market and traceability along the supply chain.