Document Type : Primary Research paper
The alterations caused during water recirculation are little known in Brazil, especially in relation to the dynamics of the water and phytoplankton in a cultivation setting. The aim of the present study was to characterize the quality of the water and phytoplankton on shrimp farms raising Litopenaeus vannamei in northeastern Brazil that use either partial or total recirculation systems. Collections were performed in the supply, distribution and drainage channels at both low and high tides. Analysis of variance, followed by Tukey’s test, was used for the statistical analysis, with the level of significance was set at P < 0.05. On the farm with partial water recirculation, the response variables total ammonium (1.81 ± 0.78 mg.L-1), nitrite (0.10 ± 0.03 mg.L-1), phosphate (2.12 ± 0.5 mg.L-1), Bacillariophyta (520.625 ± 159.983 cells.mL-1), Chlorophyta (936.250 ± 416,309 cells.mL-1) and Pirrophyta (10.078 ± 2.762 cells.mL-1) were higher in the drainage channel. On the farm with total water recirculation, total ammonium (1.59 ± 0.01 mg.L-1) and Pirrophyta (27.046 ± 435 cells.mL-1) were higher in the drainage channel. The water recirculation systems (partial and total) achieved satisfactory levels for the cultivation of Litopenaeus vannamei.