DYNAMICS OF ANTIOXIDANT ENZYME RESPONSES IN MUGIL CAPITO ACROSS SEASONAL CYCLES IN QARUN LAKE, EGYPT

Environmental pollution has become a global concern due to the ability of contaminants to disperse across geographical boundaries through wind and water currents. Aquatic ecosystems are particularly vulnerable, as they receive and accumulate pollutants from multiple anthropogenic sources. Lake Qarun, Egypt, is subjected to substantial environmental stress as it receives approximately 450 million cubic meters of agricultural and sewage drainage water annually through a network of twelve drains, primarily Al Batts and Al Wadi drains. These effluents contain a wide range of organic and inorganic pollutants that may adversely affect the lake’s ecological integrity and resident aquatic organisms. Fish are widely recognized as effective bioindicators of environmental contamination because they accumulate pollutants directly from water via respiration and indirectly through dietary intake. Continuous exposure to such contaminants can induce oxidative stress through the generation of reactive oxygen species (ROS), leading to disturbances in cellular homeostasis. Antioxidant defense systems, including key enzymatic antioxidants, play a crucial role in protecting fish tissues against oxidative damage. Variations in antioxidant enzyme activities can therefore serve as sensitive biomarkers for assessing environmental pollution and seasonal stress. his study evaluates the seasonal changes in antioxidant enzyme activities in Mugil capito inhabiting Lake Qarun to assess the impact of pollutant exposure across different seasons. By monitoring biochemical responses in fish, the study aims to provide insight into the oxidative stress status of the lake ecosystem and contribute to ongoing environmental monitoring efforts. The findings highlight the importance of biomarker-based assessments in detecting sub-lethal effects of pollution and support the implementation of mitigation strategies to reduce ecological risks in heavily impacted aquatic systems.