EVALUACIóN DEL POLICULTIVO DE BOCACHICO Prochilodus magdalenae Y TILAPIA Oreochromis niloticus UTILIZANDO SUPERFICIES FIJADORAS DE PERIFITON: EVALUATION OF THE POLYCULTURE OF BOCAChICO Prochilodus magdalenae AND TILAPIA Oreochromis niloticus USING PERIPHYTON FIXING SURFACES

fishculture is very important to satisfy human food demand. however, the ignorance in more efficient and environment-friendly systems is a big problem for fish farming activities. tilapia-bocachico polyculture is of great interest; tilapia, for the excellent productive characteristics, and bocachico for being a bottom-feeder specie, beside of the great socio-cultural value in this region. an alternative approach is the adoption of periphyton-based pond systems; periphyton can: be a food source for fish and improve water quality, thus becoming into a highly efficient and cleaner system. with the aim to evaluate the periphyton effects on performance of tilapia-bocachico polyculture, a trial was carried out for 8 months. eighteen 90 m2 earthen ponds were used under polyculture conditions at low stocking density (2.6 tilapia/m2, 0.7 bocachico/m2). these ponds were not fertilized during the experimental period. plastic tubes of 1.2 m and 6 cm in diameter were used vertically as periphyton substrate at 3.3 tubes/m2 rate. three alimentary strategies were used: 0 (without food), fish feed (20% protein) and fish feed (25% protein); thereby constituting a factorial experiment 2x3 in a randomized complete block with three replications per treatment. they were analyzed using anova with a general linear model (glm) (p < 0.05). there were no effects of substrates on the study variables, but simple effects of alimentary strategies on the productive parameters. other parameters are being analyzed and it is still premature to conclude.