3. Results
B. gonionotus culture in rice fields resulted in extremely different production results
(Table 2): the net production varied between 1.7 and 547.7 kg/ha, the SGR between 0.27%
and 3.58% body weight/day, and the harvesting weight between 8.5 and 253.9 g/fish.
The multiple regression solution includes six significant variables which explain 73.5%
of the total variation (Table 4). In the wet season, B. gonionotus had a high SGR. Adding
inorganic fertilizer or pig manure increased the SGR. In the presence of a high biomass of
O. niloticus or wild fish, the SGR dropped, suggesting interspecific competition. The
lower SGR with increasing B. gonionotus standing biomass (Fig. 1) suggests intraspecific
competition. The variables used to indicate the different rice stages had no effect on SGR.