stresses catfish easily, frequent counting and
weighing for adjusting feed rate can upset feeding
behavior and cause infections. Comparing the catfish
varieties cultured in Thailand, the hybrid (Clarias
macrocephalus x C. gariepinus) exhibits an average
FCR of 1-1.5, which is considerably lower than the
pure native species.
The tilapia production was outstanding, with total
harvests of 80.3 and 62.8 kg and with average daily
weight gains of 2.7 and 2.4 g/fish in ponds A and B,
respectively. The consistently higher chlorophyll
biomass and lower Secchi disc depth in pond A
indicate that a more abundant food source was
available for tilapia, which grew to 444 g/fish
compared to 367 g/fish in pond B (Table 3). The
extrapolated tilapia production from the present
experiment was approximately 8,000 kg/ ha/year, a
level of production which surpasses that of both
conventional integrated fish-livestock system (AIT
1986) and a system optimally fertilized with chicken
manure (Diana et al. 1988).