Córrego Alegre reservoir’s phytoplanktonic community qualitative analysis for pond fish breeding, Pantanal of Miranda, MS

Abstract

 The Córrego Alegre reservoir belongs to Miranda river sub-basin, in Pantanal of Mato Grosso do Sul, and is utilized for pond fish breeding, an activity which promotes an intense raise of nutrients, caused mostly by the addition of animal feed into the water. The accumulation of these nutrients, associated with high solar luminosity stimulates the development of a phytoplanktonic community. With the intent of analyzing the composition of the phytoplanktonic community and the water physical and chemical variables, samples were collected from the surface of the water in August and December 2005 and February and April 2006. The phytoplankton samples were collected using planktonic net of 20 µm and preserved with 4% formaldehyde solution. During the study, the results obtained show 37 genders, being Clorophyceae and Cyanobacteria the richest classes qualitatively. The presence of potentially toxic Microcystis, Oscillatoria, Planktothrix and Cylindrospermopsis cyanobacteria impose a risk to the fish breeding activity, for it may grant a displeasing taste to the flesh of the bred animal and toxicity to the water.