 As early as the 1920s, it was proposed to introduce a large pelagic predator such as the Nile perch to improve the fisheries in the lake.At the same time it was warned that this could present a serious danger to the native fish species and required extensive research into possible ecological effects before done.These warnings primarily concerned the native tilapia "O. esculentus", as the smaller haplochromine cichlids (despite playing an important role in local fisheries) were regarded as "trash fish" or even vermin by the British colonial authorities.