Acute Toxicity of Tubli (Derris elliptica) in African Catfish (Clarias gariepinus) and Red Tilapia (Oreochromis aureus x Oreochromis mossambicus)

Tubli (Derris elliptica) is a potential piscicide due to its bioactive compound, rotenone. The piscicidal effect of Derris elliptica root powder was evaluated at different concentrations against the African catfish (Clarias gariepinus) and the red tilapia (Oreochromis aureus × Oreochromis mossambicus). In terms of its acute toxicity for the red tilapia, treatments five (2.94ppm) to ten (8.82ppm) showed a significantly higher mean mortality of 100%. This indicates that even at a lower concentration of 2.94ppm, the root powder can effectively kill the red tilapia. The computed LC₅₀ for the red tilapia is 2.829ppm (2.22mg/ L). Regarding the duration of its effectiveness, the tubli root powder lost its efficacy nine days after application. Additionally, no mortality was recorded for the African catfish within three days. For the African catfish, acute toxicity was significantly higher in treatments three (8.82ppm) to five (10.78ppm), with mean mortality ranging from 78.33 to 91.66%. The computed LC₅₀ for the African catfish is 7.495ppm (5.73mg/ L). This demonstrates the high toxicity of tubli root powder and its potential application for eradicating unwanted fish species during pond preparation. Different extraction methods and additional fish species should be explored to further evaluate the effectiveness of Derris elliptica.