Relative effects of nutrient emission from intensive cage aquaculture on the semiarid reservoir water quality.
The effects of cage aquaculture on freshwater ecosystems are determined by multiple farming and environmental variables, and thus, the assessment of a wide range of abiotic and biotic variables enables better understanding of the impacts generated by this nutrient source. This study was carried out at Castanhão reservoir located in the State of Ceará, which is the largest Brazilian producer of Nile tilapia in cage systems, wherein about 8000 reservoirs provide a vast area to expand not only this important socio-economic but also pollution-prone activity. Nutrient mass budget, water quality monitoring, hydrodynamic characterization, and elemental/stable isotopic composition of end-member products were measured in cage aquaculture and other reservoir areas in order to determine the relative effects on reservoir conditions. Nutrient budgets showed that 34% of the artificial feed was lost to the water column but water quality monitoring and isotopic composition analysis suggested that the cages were not extensively impacting the water quality probably because of the physiographic and hydrodynamic features of the cage site.
Núcleo em Ecologia e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro (UFRJ) campus Macaé, Macaé, RJ, CEP: 27965-045, Brazil. molisanimm@yahoo.com.br.
Mauricio Mussi
MM
Molisani
Instituto de Ciências do Mar (LABOMAR), Universidade Federal do Ceará, Fortaleza, CE, Brazil.
Thiago Maia
TM
do Monte
Instituto de Ciências do Mar (LABOMAR), Universidade Federal do Ceará, Fortaleza, CE, Brazil.
George Harrison
GH
Vasconcellos
Instituto de Ciências do Mar (LABOMAR), Universidade Federal do Ceará, Fortaleza, CE, Brazil.
Hortência
H
de Souza Barroso
Instituto de Ciências do Mar (LABOMAR), Universidade Federal do Ceará, Fortaleza, CE, Brazil.
Maria Odete Parente
MO
Moreira
Departamento de Química Analítica e Físico-Química, Universidade Federal do Ceará, Fortaleza, CE, Brazil.
Helena
H
Becker
Laboratório de Ciências Ambientais, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brazil.
Carlos Eduardo
CE
de Rezende
Laboratório de Ciências Ambientais, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brazil.
Marcos Alberto Lima
MA
Franco
Departamento de Engenharia de Pesca, Universidade Federal de Santa Catarina, Laguna, SC, Brazil.
Eduardo Guilherme Gentil
EG
de Farias
Laboratório de Ecologia Isotópica, Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, São Paulo, SP, Brazil.
Plínio Barbosa
PB
de Camargo
D017756:Aquaculture; D001938:Brazil; D017753:Ecosystem; D004784:Environmental Monitoring; D005502:Food; D005618:Fresh Water; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D014873:Water Pollutants / Q000032:analysis*; D060753:Water Quality
D014873:Water Pollutants; D010758:Phosphorus; D009584:Nitrogen
Cage aquaculture impact; Hydrodynamic; Nutrient; Reservoir; Stable isotope; Tilapia