Effect of stocking density on growth, production and economic benefits of mixed sex N ile tilapia ( O reochromis niloticus ) and A frican sharptooth catfish ( C larias gariepinus ) in polyculture and monoculture

On‐farm fish production experiments were conducted for 240 days to investigate the effect of stocking density on growth, yield and economic benefits of N ile tilapia ( O reochromis niloticus ) in monoculture and polyculture with A frican sharptooth catfish ( C larias gariepinus ). Low stocking density ( LSD ), medium stocking density ( MSD ) and high stocking density ( HSD ) of 30 000, 60 000 and 90 000 fish ha −1 respectively, were tested. O . niloticus cultured in polyculture attained significantly higher mean weight gain than those cultured in monoculture. O . niloticus and C . gariepinus raised together in polyculture attained significantly higher net annual yield than O . niloticus cultured alone in monoculture. Profitability analysis using partial enterprise budgets revealed that polyculture is a more profitable system than monoculture. The highest growth, yield and economic benefits were achieved at HSD and MSD than at LSD with no significant difference between HSD and MSD . Results demonstrate that farmers can achieve the highest net yield and economic benefits by culturing O . niloticus and C . gariepinus in polyculture at HSD and MSD , preferably MSD for economic reasons.