Effect of Handling Stress on Primary and Secondary Stress Responses of the Catfish, Clarias batrachus

Cortisol is a major hormone directly associated with stress in fish and is a reliable physiological indicator of primary stress response in fish, whereas glucose and osmolality are the indicators of secondary stress response in fish. This study explored the stress levels in the catfish, Clarias batrachus (Magur) by measuring the cortisol, glucose, and osmolality levels in plasma by exposing the fish to three different kinds of interventions namely, non-anaesthetized, anaesthetized, and stressed. No statistically significant changes were reported in the plasma cortisol, plasma glucose, and plasma osmolality levels when the blood samples were collected after the three interventions. These results indicated that Clarias batrachus is a sturdy fish, which can withstand routine laboratory handling, and that the blood samples can be collected without anaesthetization.