Environmental stress responses to marine mucilage: Oxidative damage in economically important seafood from the Sea of Marmara

Abstract

Marine mucilage, a gelatinous organic substance driven by nutrient enrichment and rising sea temperature, poses significant threats to marine biodiversity and fisheries. This study examines the oxidative stress responses in four seafood species: deep-water rose shrimp (Parapenaeus longirostris), common sole (Solea solea), European anchovy (Engraulis encrasicolus), and Atlantic horse mackerel (Trachurus trachurus) in Sea of Marmara, Türkiye, between September 2021 to April 2022. Biomarkers of oxidative stress—reduced glutathione (GSH), lipid peroxidation (LPO), and antioxidant enzyme activities (glutathione reductase, glutathione-S-transferase, and superoxide dismutase), were analyzed in muscle tissues to evaluate species-specific resilience to mucilage. Findings revealed distinct variations among species. Deep-water rose shrimp demonstrated the highest GSH level and lowest LPO level, indicating robust oxidative stress defense. In contrast, pelagic species, including European anchovy and Atlantic horse mackerel, exhibited decreased GSH and elevated LPO levels and variability antioxidant enzyme activities, reflecting greater sensitivity to environmental stress. During the marine mucilage, in addition to mucilage distribution, fluctuations in seawater temperature (between 7.4°C and 24.4°C), and physiological stress caused seasonal changes in various enzymatic activities of the fish species investigated in our study. These results highlight the risks posed by marine mucilage to seafood safety and the ecological balance of marine environments. The vulnerability of pelagic species, combined with their economic and nutritional importance, underscores the urgency of mitigation strategies. This study emphasizes the need for integrated “One Health” approaches to safeguard ecosystem health and food security in the region.