respectively. Those nutrient outputs fertilized the
ponds at a rate of 2.48 kg N and 0.94 kg P ha-'.d-' in
low density pond, and 5.14 kg N and 1.94 kg Plhdday
in high density ponds. Both treatments gave a N:P ratio
of 2.6: 1. In terms of optimal rate of pond fertilization,
those wastes provided nutrients in a range similar to
that recommended for semi-intensive pond culture of
tilapia in the tropics (Knut-Hansen et ul., 1991). The
resultant tilapia production in the present experiment
was equivalent to 4260 and 5 334 kglha-'.yr-', which
was comparable to ponds fertilize with conventional
chicken manure (Green, 1992) or chemical fertilizers
(Diana et al., 1991).
This catfish-tilapia integrated culture system is
particularly appropriate for small-scale farmers in
Thailand, where catfish fetches higher market value
than tilapia does. Catfish reared in cages are easy and
convenient for harvesting without needing to drain the
ponds.
Tipalia production is basically free of charge because
it requires no additional feed nor fertilizer input.
The experiment demonstrated that the practicality
of integrated fishlfish production system based on
intensive culture of catfish in cages and semi-intensive
tilapia in surrounding open pond. This approach is not
only to augment the total aquaculture production, but
also environmental friendly.