POLYCULTURE OF NILE TILAPIA (OREOCHROMIS-NILOTICUS) AND AUSTRALIAN RED CLAW CRAYFISH (CHERAX-QUADRICARINATUS) IN EARTHEN PONDS

Nile tilapia (Oreochromis niloticus) and Australian red claw crayfish (Cherax quadricarinatus) were cultured alone and together in replicate 0.02 ha earthen ponds to assess the nature and intensity of species interaction in polyculture. Treatments were: (I) 10000 tilapia per hectare, (II) 10000 tilapia plus 25000 crayfish per hectare and (III) 25000 crayfish per hectare. All ponds were fed a 32% crude protein, pelleted catfish feed at monthly-adjusted rates based on stocked tilapia biomass. After 100 days of polyculture, ponds were harvested. Tilapia growth, reproduction and food conversion were adversely affected by the presence of crayfish (P<0.01). Crayfish growth, incidence of intersexuality and percentage of berried females were not affected by the presence of tilapia (P<0.01).