Assessing the nutritional quality of Atlantic horse mackerel and European anchovy during marine mucilage: A climate-induced threat to food security

This study investigates the seasonal variation in the fatty acid composition and lipid quality indices of European anchovy (Engraulis encrasicolus) and Atlantic horse mackerel (Trachurus trachurus) in the Sea of Marmara during a season affected by the 2021 mucilage event. Fatty acid analyses were performed throughout the 2021-2022 commercial fishing season, covering autumn, winter, and spring. In European anchovy, palmitic acid significantly declined from 21.24 % to 15.47 %, and oleic acid peaked in winter at 19.67 % (p < 0.05). In Atlantic horse mackerel, palmitic acid dropped from 20.99 % to 17.76 %, while EPA increased significantly from 5.44 % to 6.88 % (p < 0.05). Health indices also varied significantly: the hypocholesterolemic/hypercholesterolemic (h/H) ratio increased, while the atherogenic index (AI) and thrombogenic index (TI) decreased in both species, particularly in spring (p < 0.05). Autumn samples showed lower omega-3 (omega-3) levels and less favorable indices, consistent with short-term ecosystem disturbance. If mucilage events become more frequent with climate change and eutrophication, their cumulative associations with seafood quality warrant attention. Regular lipid composition monitoring that integrates environmental context is needed to assess ecological and nutritional implications.