EFEITO DO MANEJO NA PRODUÇÃO DE PEIXES EM SISTEMA DE POLICULTIVO

The experiment was set up in 6 ponds of the same dimensions (9.0 x 5.0 x 1.2 m) at Fish Culture Section of the Faculdade de Ciencias Agrarias e Veterinarias de Jaboticabal, Sao Paulo State, Brazil. Six different treatments were tested as preliminary observations, with three different management systems, each of them with two stocking densities: 1.1 and 2.2 fingerling/m2. Ponds were stocked with fingerlings of common carp (Cyprinus carpio communis), hybrid tilapia obtained through the cross of male Sarotherodon hornorum x female S. niloticus and a Brazilian catfish (Rhamdia hilarii), at the ratios of 2:2:1. Trials consisted on fertilization only of fish ponds with chicken manure at the dosis of 12 ton/ha.year quarterly applied and 750 kg/ha.year of ammonium sulphate applied in the ponds where fish was only fed twice a day with a diet containing 26.3% crude protein, and ponds that were fertilized and received also supplementary feeding. Water temperature at the surface of the ponds was daily observed and it was determined weekly the fluctuation of the following hydrologic parameters: dissolved oxygen and pH value. Smallest productions, 1,483.70 and 1,421.8 kg/ha.6 months, were obtained; these productions were not dependent on stocking density of the ponds. The best productions were obtained in the ponds fertilized and with supplementary feeding where the fish production were, respectively, 3,650.1 and 4,626.9 kg/ha.6 months for the ponds stocked with 1.1 and 2.2 fish/m2, showing clear influence of stocking density.