Biological Control of Vector Mosquitoes by Some Common Exotic Fish Predators

Predation experiments using Cyprinus carpio Linnaeus (1758), Ctenopharyngodon idella (Valenciennes 1844),Oreochromis niloticus niloticus (Linnaeus 1758) and Clarias gariepinus (Burchell 1822) were conducted against fourth instar Anopheles stephensi Liston (1901) larvae and pupae at varying prey and predator densities. The relative prey consumption rates ofthe four fish species for An. stephensi larvae and pupae during 24-hour experiments under laboratory conditions were C. gariepinus C. idella C. carpio O. n. niloticus. Predatory efficacy was positively related with prey density and inversely related with watervolume (search area). A significant decrease in larval abundance in dipper samples was observed at 30 and 45 days after introduction of fishes (30 individuals each) in field conditions. The efficacy of the fish under field conditions was also indicated by significantincreases of larval mosquito abundance at 30 and 45 days after removal of fishes.