ANAESTHETIC EFFECTS OF SODIUM BICARBONATE AT DIFFERENT CONCENTRATIONS ON AFRICAN CATFISH (Clarias gariepinus) JUVENILES

In the present study, anaesthetic effects of different sizes (5, 10, 15, 20, 25, 30, 35 and 40g) of African catfish (Clarias gariepinus) juveniles was investigated at different concentrations (0/control, 10, 15, 20, 25, 30, 35, 40, 45, 50 g/L) of sodium bicarbonate.Juveniles were bath immersed in each of the different concentrations of sodium bicarbonate solution for 5 minutes and recovery times in clean aerated water was established.Juveniles took between 0.67 to 5.44 minutes to reach full anaesthesia and 0.66 to 4.25 minutes to recover fully from anaesthesia.An inverse exponential relationship was observed between sodium bicarbonate concentrations and induction time, whereas exponential relationship was observed between sodium bicar-bonate concentrations and recovery time.Size of C. gariepinus juveniles significantly affected the induction time (P < 0.05) with smaller juveniles getting to full anaesthesia faster than bigger juveniles at the same concentration of sodium bicarbonate.In addition, recovery time was size dependent where smaller C. gariepinus juveniles took significantly longer time (P < 0.05) to recover from anaesthesia than bigger juveniles.All juveniles reached anaesthesia and recovered in less than 5 minutes except for 30 g juveniles at 15g/L of sodium bicarbonate which was anaesthetized at 5.44 minutes.