Aquaculture research vol:32 issue:11 pages:913-921
Trichogaster pectoralis Regan is often cultured successfully in rice fields in South-cast Asia. However, since the advent of high-yielding rice varieties and intensive rice cropping, several reports suggest poorer growth performance of the species. In this paper, we investigated the growth performance of T. pectoralis in rice-fish systems characterized by intensive rice culture and extensive to semi-intensive polyculture of Oreochromis nilotictis (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 intensification of rice cropping did indeed result in poor T. pectoralis growth. Successful T. pectoralis culture is only possible in areas of traditional rice cropping.