Análise comparativa do cultivo do camarão marinho Litopenaeus vannamei em sistemas com biofloco e convencional no litoral sul de Pernambuco

Abstract

Among the new management technologies which have been proposed for carciniculture, the "BFT" system (Bio-Floc Technology) has shown to be key in allowing crops with high stocking densities, higher biosafety and reduced water exchange. The purpose of this study was to analyze the zoo-technical performance, water quality and the microbiological aspects of large scale culture systems of Litopenaeus vannamei in super-intensive with biofloc formation (BFT) and conventional (CON) systems on the southern coast of Pernambuco. For BFT, two tanks of 200m², stocked with 375 shrimp/m² were used and cultured for 130 days. Concerning the CON system, two ponds were utilized (2.85 ha each), stocked with 12 shrimps/m2 cultured through a period of time averaging 105 days. Weekly biometrics helped monitor shrimp growth and adjust feeding supply in both systems. The water physico-chemical variables were monitored daily, and even with significant differences between the BFT and CON systems, they were within appropriate levels for the species in relation to dissolved oxygen, pH, temperature and salinity. At the end of culture, shrimps displayed mean weight ± SD of 11,41 ± 2,06 g and 10,52 ± 2,23 g, survival rate of 32,4% and 59,1%, and production (Kg/m2) of 1,39 and 0,072, for BFT and CON systems, respectively. With respect to the concentrations of nitrogen compounds (NH3 and NO2), levels were high during the cultivation only in the BFT system. In the results related to microbiology, there was the presence of bacteria of the genus Vibrio and high load of fecal coliform in the shrimp cultured in the CON system. As for the BFT system, the presence of Staphylococcus coagulase-positive was found in shrimps from this culture. Despite the technical problems, which can be easily corrected, the BFT system utilized on a commercial scale in northeastern of Brazil showed great potential for replacing the conventional one, and may become a good alternative to increase productivity and control of effluents, thus confirming its sustainability.