Governments in Southern Africa in partnership with research and development agencies have put forth initiatives to improve some of the indigenous species ( the Kafue Bream, Oreochromis andersonii in Zambia, O. shiranus in Malawi and O. mossambicus in Mozambique and South Africa) through Genetic Improvement Programs (GIPs) . However, data on performance for the popular O. niloticus alongside these other key indigenous species is still limited. In Zambia, O. niloticus contributes up to 69% of the total national aquaculture production, followed by O. andersonii especially in commercial establishments. In the present study, performance of these two major contributors to the Zambian aquaculture production; O. niloticus and O. andersonii sourced from different hatcheries and fed a commercial feed was evaluated over a period of 175 days in a controlled environment. The fish were all subjected to the same single feeding regime and management throughout the experimental period.
Results revealed that mean body weight at harvest for O. andersonii was significantly lower than that of O. niloticus (P<0.05) while there was no significant difference in body weight between strains within either species (Table 1). Similarly the mean specific growth rate (SGR) and the daily growth coefficients (DGC) were also significantly lower for O. andersonii strains than the O. niloticus ones, with the O. niloticus growing more than one and half times the rate of O. andersonii .
This clearly demonstrates that O. niloticus and O. andersonii perform differently under the same management regime, and while both species showed good FCR rates in the experiment, that of O. niloticus exceeded O. andersonii . From this study, Oreochromis niloticus thus presents itself as currently a viable farm production efficient species utilising less feed resources in comparison to O. andersonii and hence less cost on feed in addition to having a smaller carbon print on the environment. This work provides rare benchmarking up-to date information on performance of these species and hatchery strains in Zambia. These data are important for future decisions concerning which species to grow given the relationship between fast growth performance, profitability and sustainability of the individual farmer operations as well as the broader aquaculture industry.