Histopathological Assessment Of Mystus Gulio In Relation To Environmental Stress In Veli Lake, Thiruvananthapuram, Kerala

Abstract

Histopathology is a sensitive biomonitoring approach because tissue-level lesions can integrate exposure to complex mixtures of environmental stressors. This study assessed environmental stress in Veli Lake, Thiruvananthapuram, using Mystusgulio as a sentinel fish species. Two hundred fish were examined over ten months, alongside monthly measurements of water temperature, pH, salinity, dissolved oxygen, and hardness. Histological analysis of gill and liver tissues revealed substantial pathological changes, including lamellar shortening and fusion, epithelial lifting, tissue degeneration, hepatocellular disorganization, pyknosis, pigment deposition, vascular enlargement, and necrosis. Gill cyst-like lesions and monogenean attachment were also observed. The findings indicate that fluctuations in pH, salinity, hardness, and dissolved oxygen were associated with significant tissue injury, demonstrating the potential of M. gulio histopathology as a biomonitoring tool for environmental stress in Veli Lake.