Daily mass balance of phosphorus and nitrogen in effluents of production sectors of trout farming system/ Balanço de massa diário de fósforo e nitrogênio em efluentes de setores de criação em truticultura

• Published in: Acta limnológica brasiliensia 2015-07, Vol.27 (3), p.330-330
• Main Authors: Moraes, Munique de Almeida Bispo, do Carmo, Clovis Ferreira, Ishikawa, Carlos Massatoshi, Tabata, Yara Aiko, Mercante, Cacilda Thais Janson
• Format: Article
• Language: English
• ISSN: 0102-6712; 2179-975X
• DOI: 10.1590/S2179-975X1415

The mass balance has recently been applied in Brazilian aquaculture. In relation to trout farming, few studies have used this methodology as environmental indicator, especially when considering each development stage of fish. The daily mass balance allows an estimate of nutrients discharge, because the sampling effort over 24 hours enables to monitor the variations throughout the day. This study aimed to identify the breeding sector (fingerlings, juveniles and adults) in trout farming contributes with the great discharge of phosphorus and nitrogen in the effluent. The concentrations of total phosphorus (TP), orthophosphate (PO^sub 4^-P), total nitrogen (TN) and ammonium (NH^sub 4^-N) were determined in affluent and effluents of the production system. The environmental indicators were calculated based on the values of nutrients loads and by quantifying the daily discharge of nutrients from the mass balance method. Over the 24 hours, the trout farming exported an average of 0.26 kg TP, 0.11 kg PO^sub 4^-P, 3.11 kg TN and 0.18 kg NH^sub 4^-N.