Impact of maintenance of Macrobrachium rosenbergii broodstock prawn on water quality

Abstract

The objective was to evaluate the impacts caused on pond water quality by maintenance of Macrobrachium rosenbergii broodstock. During eight weeks it was determined pH, dissolved oxygen (DO), conductivity, turbidity, particulate suspended material (PSM), nitrogen (N) and phosphorus (P), all in inlet and effluent water. All variables presented higher values in the effluent, except OD. Ammoniac N concentration (0.013 mg L^-1) was 2.7 times higher in the effluent pond; NO₂-N (0.019 mg L^-1), 2.3; NO₃-N (0.139 µg L^-1), 1.8; PO₄-P (0.065 mg L^-1), 7.2; and DP (0.104 mg L^-1), 4.9 times higher. For TKN (0.67 mg L^-1) and TP (0.235 mg L^-1), the values in the pond effluent represent an increase of 0.27 mg L^-1 and 0.175 mg L^-1, respectively. The maintenance of M. rosenbergii broodstock increase the nutrient concentrations, mainly TP, and prevent effluent pond released into receiving water bodies on 1, 2 and 3 classes of the CONAMA N° 357 Resolution.