The daily weight gain (DWG) expressed as g fish day)1, net production (NP) expressed as kg m)3 day)1 and feed conversion ratio (FCR) were calculated using the following formulae: DWG ¼ðfinal weightinitial weight)=no: fish=time ðdaysÞ NP ¼ðfinal biomass ðkg m3Þinitial biomassðkg m3ÞÞ FCR ¼ total dry feed fed ðkgÞ=ðfinal fish biomass ðkgÞ initial fish biomass ðkgÞÞ: