Avaliação das comunidades planctônicas e bentônicas de microalgas em viveiros de camarão (Litopenaeus vannamei)

Abstract

The present study aimed to evaluate the dynamics of planktonic and benthic communities of microalgae, and establish relationships with the hydrological variables, management practices and the production data of the shrimp ponds. During one year, three Litopenaeus vannamei ponds and the affluent channel were analyzed by taking phytoplankton and benthos samples twice a week. In the ponds were recorded informations about the hydrological variables (temperature, pH, dissolved oxygen and salinity), climatic (precipitation), culture management (fertilization data) and the production data (culture time, final weight, weight gain, survival, feed conversion ratio and productivity). The density, abundance and occurrence frequency were used as parameters to evaluate the microalgae community. The Cyanobacteria dominated the plankton in all cycles, reaching the relative abundance of 80%, being the Pseudoanabaena genus the main responsible for this domination. In the benthos, the diatoms dominated with abundance over 85%. The phytoplankton reached higher densities in the ponds, whereas thephytobenthos was dominant in the affluent channel. A positive relation between the benthos diatoms and the shrimps´ growth was observed.