carpio L. In this study, we used the data of eight experiments into such polycultures at the
Co Do rice–fish experimental station to look whether the rice stage or fish biomass had any effect on
the specific growth rate (SGR) of B. gonionotus. The B. gonionotus net production figures varied
from 1.7 to 547.7 kg/ha, while the SGR varied from 0.27% to 3.58% body weight/day.We found that
SGR values did not depend on the developmental stage of the rice crop. However, the SGR values
significantly decreased with increasing standing biomass (SB) of B. gonionotus, O. niloticus or wild
fish. We concluded that intraspecific and interspecific competition is an important issue in B.
gonionotus culture in rice fields. Besides this, SGR values were higher in the wet season and in plots
with inorganic fertilizer or pig manure application.
D 2002 Elsevier Science B.V. All rights reserved.
Keywords: Rice–fish culture; Barbodes gonionotus; Oreochromis niloticus; Cyprinus carpio; Polyculture;
Competition