Behavioural and Some Physiological Assessment of Glyphosate and Paraquat Toxicity to Juveniles of African Catfish, Clarias gariepinus

The impact of acute exposure of Clams gam/mitts juveniles to commonly used herbicides, glyphosate and paraquat was evaluated through changes in fish behaviour and mortality Juveniles of the African catfish were exposed to varying acute concentrations of glyphosate and paraquat The fishes responded, exhibiting different behavioural abnormalities like hyperactivity, abnormal swimming, restlessness, loss of equilibrum and haemorrhage. Observation of opercular ventilation count (OVC), tail fin movemant rate (TMR) and air gulping index (AGI) showed a marked difference between control and exposed fishes, indicating that the herbicides negatively impact on these parameters. These behavioural and morphological anomalies became more pronounced with increasing concentrations of the herbicides. Mortality was also observed to be concentration dependent. After 96 h of exposure, the 96hr LC,0 for paraquat was found to be 0.07mg/L while that of glyphosate was found to be 0.530mg/L The result revealed that glyphosate and paraquat have the ability to induce unusual behaviours in fish and can therefore serve as reliable indicators of toxicity in environmental impact assessment programmes