Estudo da viabilidade técnica e econômica do cultivo de tilápia do Nilo Oreochromis niloticus,linhagem Chitralada, em tanques-rede com duas densidades de estocagem

Abstract

Nowadays, in reservoirs of São Francisco, Paulo Afonso, Bahia, there are about 1500 pond-nets in operation. The job aimed to determine the better density stored to the tilapia culture of Nilo Oreochromis niloticus, Chitralada strain, studying the standards of the development and the possibility of technical and economical culture for the commercial and operational reality of fish culture Pedra D’água, that has 180 pond-nets of 6 m3 in operation and provide fish to the exporting deep freze plant. To this experiment were used eight cages with 17mm net, where were stored juveniles with the weight changing between 28.75 ± 0.96 g (T1) and 28.25 ± 0.50 g (T2). Were carried two treatments T1 (150 fish.m-3) and T2 (200 fish.m-3). During the culture were analyzed the following variety of water: transparence, oxygen, pH and temperature. Were carried out two weeks biometric with 10% samples of population of each pond-net. At the end of 157 days of the culture, the fishes from each pond-net were submitted a categorization and put to the no harvest. The production distribution per size fish was adverse the density of 200 fish.m-3 (T2), once produced the bigger biomass of small fishes (19.38 ± 1.71%) with low paid (R$ 2.00/kg), and smaller of big fishes (35.76 ± 0.57%), with better paid (R$ 2.70/kg), when compared with the density production of 150 fish.m-3 (T1) (7.04 ± 2.62% and 50.04 ± 1.51%, respectively). The results demonstred that the media production in the density 200 fish.m-3 was statistic superior in small fishes and medium, and inferior in big fishes (p<0.01). In the growth evaluation, among the medium evaluation, observed that T1 was superior from T2 in: weight, length ends, daily weight got, survive rate, specific growth, weight gain relate and feed efficient. The values to T2 were bigger when end biomass was evaluated, the biomass gain and the noticeable feed conversion. Over the results to the capacity of production of the fish culture Pedra D’água, the economic evaluation of the culture demonstred T1 was superior from T2 in the annual gain, annual liquid profits. The profits index of the T1 was 5.86% while T2 was7.94% and the profitable operational was 21.19% and 13.22%, respectively. The profitable index was of 61.17% for T1 and 34.05% for T2. The sustain point was of 40.63% and for T2 of 55.14%. The return to the money invested was in 1.63 year for T1 and 2.94 years for T2, demonstrating that in the real conditions of the market in Paulo Afonso, the better economic performances and productive happened in treatment T1 (150 fish.m-3).