Avaliação da qualidade de água no cultivo da Tilápia do Nilo (Oreochromis niloticus) em tanques terra na unidade de produção Papa-Pesca

Abstract

Water quality is one of the main challenges in aquaculture, as inadequate management can lead to negative impacts on production. This study aimed to evaluate the water quality in Nile tilapia (Oreochromis niloticus) farming in earthen ponds and the management of effluents. The study was conducted at the Papá Pesca Lda. production unit and was preceded by a three-month internship, from September to November 2023, during which the following activities were monitored: pond preparation, transport and stocking of fingerlings, feeding, water quality control, pond cleaning, and biometric assessments. Water samples were collected weekly, except for temperature, dissolved oxygen, and transparency, which were measured daily. Five sampling points were analyzed, covering water inflow into the ponds, its quality during the production cycle, and the characteristics of the effluents at the outflow. The results of the physic-chemical parameters showed temperature ranging from 23.6 to 24.9 oC, dissolved oxygen from 2.03 to 5.00 mg/L, pH from 7.60 to 8.00, nitrate from 0.00 to 15.00 mg/L, nitrite from 0.00 to 0.50 mg/L, hardness from 106.7 mg/L to 167.0 mg/L, and alkalinity from 107 to 184 mg/L. It was observed that values within the recommended range were recorded at the water source, while higher values were detected in the wastewater (effluents), indicating an accumulation of dissolved compounds throughout the production process. The study demonstrated that the sedimentation process provides a slight improvement in water quality, partially reducing the concentration of compounds related to water quality parameters.