Management techniques for the cultivation of White Shrimp Litopenaeus vannamei (Boone) in a biofloc system
The rapid expansion of shrimp farming in recent decades has created many environmental problems such as the destruction of surrounding ecosystems, the discharge of effluents, the invasion of exotic species and the spread of pathogens. In this context, the biofloc cultivation system without water renewal (BFT - Biofloc Technology) has emerged as an important alternative, since the heterotrophic bacteria present in the bioflocs assimilate the nitrogenous compounds dissolved in the cultivation water, allowing it to be reused in several cycles, making the system environmentally friendly. This thesis investigated management techniques that make it possible to intensify the cultivation of Litopenaeus vannamei in biofloc systems without water renewal.The results showed that the increase in stocking density affected growth and survival in all fattening stages of L. vannamei grown in biofloc systems. Post-larvae of L. vannamei produced at high densities, showed full compensatory growth when re-stocked at adequate densities. Fertilization with a source rich in organic carbon (cane molasses) proved to be efficient for better zootechnical performance when compared to the autotrophic system. The use of partial harvesting can be an important management tool for maximum utilization of the support capacity of the nurseries, maintaining throughout the cultivation the largest shrimp biomass that the BFT system supports. The results obtained in the present thesis can collaborate in the intensification processes for the production of L. vannamei.