Polyculture of all-male tilapia hybrids with low densities of Macrobrachium rosenbergii

Abstract

Each of six 700-m² earthen ponds was stocked with all-male hybrid fingerlings (28 g) from the cross of female Tilapia nilotica x male T. hornorum, at a rate of 0.4 fish/m². Six days later, duplicate ponds were stocked with either 0.5, 1.0 or 1.5 juvenile prawns (Macrobrachium rosenbergii) (2 g) per m². Initially 32% protein pellets were fed daily at 2.5% of fish biomass; this ratio was decreased to 1.4% by harvest. At the low, medium and high prawn densities, average yields after 20 weeks were 171, 243, and 350 kg/ha lor prawns and 1,404; 1,450; and 1,356 kglha for tilapia, respectively. At these densities, 84.4, 87.7, and 85.4% of the prawns weighed 30 g or more, whereas 75.0, 67.5, and 71.3% weighed 40 g or more, respectively. Average weight of tilapia was 395 g among all ponds, independent of prawn density.