The weights at harvest after 90 days were compared among eight Nile tilapia strains: the first generation progeny of the newly introduced four African wild strains and progeny obtained from four easting Asian strains farmed in the Philippines. The four Asian farmed strains were the widely farmed Israel strain and three others named after their most recent origins prior to introduction to the Philippines: Singapore, "taiwan" (both probably derived from introductions from Israelis and Thailand (probably of Egyptian origin). Tagged fish from all eight strains were stocked communally in 11 different farm environments including ponds, cages, and rice-fish systems, as well as lowland and upland /'locations. This required the tagging of 11,000 individual fish and was the largest experiment of its kind ever undertaken in Asia. Three of the African wild strains (Egypt, Kenya, and Senegal) grew consistently as well as or faster than the Asian farmed strains across all test environments.24 These results affirmed that there were significant genetic determinants of growth performance among these diverse Nile tilapia strains. It was also evident that, in these initial trials, wild tilapia had grown to larger weights at harvest than had tilapia descended from Asian stocks that had been farmed for more than 20 years.