Comparison trials between Oreochromis andersonii (Kafue Bream) and O. niloticus (imported species) under farm conditions in Zambia.

Abstract There has been much discussion for many years over the most suitable tilapia species to use in aquaculture. It has been thought for many years that Nile tilapia (Oreochromis niloticus) was the most productive, especially after it had been developed using the genetically improved farmed tilapia (GIFT) protocols, but no trials have taken place under standard farming conditions nor was there ever any consideration taken of the possible ecological side effects of the introduction of alien species into river systems. With the help of a small grant from the Food and Agricultural Organization of United Nations, Kalimba Farm, Zambia, undertook to carry out a direct comparison between the suitability of both O. niloticus and O. andersonii for fish culture under normal farm conditions. These trials took place over three years from 2004 to 2007. The overall results concluded that there were definite advantages for both species in different areas, but considering a genetically improved species was being compared with stock that had been genetically isolated for 25 years, the overall results were encouraging for the indigenous O. andersonii. In addition, taking into account the assumed damage to fragile river systems from the introduction of invasive O. niloticus it was felt that efforts should be made in future to encourage the use of O. andersonii as the preferred fish for aquaculture in areas of Zambia that are not already polluted with O. niloticus and, furthermore, an effort should be made to improve O. andersonii through an on-farm selective breeding programme using the GIFT protocols.