Efeito da densidade de estocagem na fase de recria do tambaqui (Colossoma macropomum) em tanques-rede na Floresta Nacional do Tapajós, Belterra/PA

Abstract

The main objective of the present study was to verify the technical viability of the juvenile production of Colossoma macropomum tambaquis in the nursery phase in cages in a Tauari lake, Tapajós National Forest. The study consisted of the evaluation of stocking densities (50, 100, 150 and 200 fish m- ³) in cages (1 m width x 1 m length x 1 m depth and 0.5 cm mesh) in storage ponds of interior of cages growth (working volume - 2 x 3 x 1.1 m - L x W x H) for 20 days. During the experimental period, 10% of the fish from each experimental unit were sampled for biometry at the beginning, 10 days and the end of the study. In conjunction with the biometrics, the physical and chemical parameters of the water (temperature, dissolved oxygen concentration, pH and electrical conductivity) were monitored. At the end of the 20 experimental days, the number of live fish from each experimental unit was recorded and the zootechnical performance of the juveniles evaluated through the following zootechnical indexes: mean final weight, weight gain, specific growth rate, apparent feed conversion, productivity and survival. The zootechnical indexes were analyzed by means of one way Analysis of Variance, at a level of 5% of probability. The parameters of water quality remained adequate for the farming of the species. Regarding the zootechnical performance, except for the apparent feed conversion and survival, significant statistical differences were found in the tambaquis created at the different storage densities (p <0.05). The performance of juveniles tended to be inversely related to the increase in density, except for productivity, which was higher for those raised at 200 fish m- ³. It is concluded that the stocking density affected the zootechnical performance of the species created in cages and that up to 200 fish m- ³ can be used in the nursery phase of C. macropomum in this system in the Tauari lake in Flona Tapajós.