In this paper, we investigated the growth performance
of T. pectoralis in rice±fish systems characterized
by intensive rice culture and extensive to semiintensive
polyculture of Oreochromis niloticus (L.),
Cyprinus carpio L. and Barbodes gonionotus (Bleeker).
In these systems, T. pectoralis recorded negative net
productions. This was mainly the result of a
negative specific growth rate (SGR) when fish had
to stay in the trench (±0.519% body weight day±1)
or when fish had free access to the rice crop
(±0.081). Only when harvested rice plants were
allowed to generate new tillers (ratooning) did
T. pectoralis perform slightly better (0.453% body
weight day±1). The SGR of T. pectoralis was low
owing to a lack of food in intensive rice systems. The
other species, all with SGR values higher than 1%
body weight day±1, clearly had a competitive
advantage over T. pectoralis. We concluded that
intensi®cation of rice cropping did indeed result in
poor T. pectoralis growth. Successful T. pectoralis
culture is only possible in areas of traditional rice
cropping.