Document Type : Primary Research paper
The effectiveness of sodium bicarbonate as an anaesthetic for Nile tilapia (Oreochromis niloticus) juveniles ranging from 2 to 27g was investigated. The juveniles were exposed to different concentrations of 0 (control), 5, 10, 15,20, 25, 30, 35, 40, 45 and 50 g/L of sodium bicarbonate solution. Fish were bath immersed in each of the different concentrations of sodium bicarbonate solution for 5 min. Generally, induction time decreased while recovery time increased with increase in sodium bicarbonate concentration. Induction and recovery times increased significantly (P < 0.05) with increasing body weight. All fish reached full anaesthesia in less than 2 min in higher concentrations of 50 g/L and no mortality occurred under any of the concentrations tested. The most optimal concentration leading to full anaesthesia in 2 min and recovery in less than 4 min was 45 g/L.