Lipid and Fatty Acid Composition of Low-Value Mediterranean Fish in Winter and Spring for Discard Valorization

Winter and Spring variations of the fat and fatty acid compositions of discards from six species of the Aegean Sea were investigated to assess the potential suitability for human or aquaculture consumption. European pilchard (Sardina pilchardus), anchovy (Engraulis encrasicolus), curled picarel (Centracanthus cirrus), gilt sardine (Saridenella aurita), horse mackerel (Trachurus mediterraneus) and bogue (Boops boops) were collected from the local fishing wharf during winter and spring. In most species, the specimens caught in spring exhibited elevated fat and n-3 long-chain polyunsaturated fatty acid content, with Sardina pilchardus showing an increase in DHA from 13.59% to 16.06% and Engraulis encrasicolus from 20.36% to 23.41% of the total identified fatty acids. Despite their lower commercial value, the high n-3 LC-PUFA content renders them nutritionally valuable and eligible for use by the aquafeed industry as an alternative to the increasingly costly fish oil. Moreover, in accordance with EU legislation banning discards and mandating the landing of unwanted catches, the valorisation of these species, in line with circular economy principles, could enhance fishers’ income, reduce waste and contribute to the long-term sustainability of marine ecosystems.