title: A coupled biogeochemical-Dynamic Energy Budget model as a tool for managing fish production ponds.
abstract: The sustainability of semi-intensive aquaculture relies on management practices that simultaneously improve production efficiency and minimize the environmental impacts of this activity. The purpose of the present work was to develop a mathematical model that reproduced the dynamics of a semi-intensive fish earth pond, to simulate different management scenarios for optimizing fish production. The modeling approach consisted of coupling a biogeochemical model that simulated the dynamics of the elements that are more likely to affect fish production and cause undesirable environmental impacts (nitrogen, phosphorus and oxygen) to a fish growth model based on the Dynamic Energy Budget approach. The biogeochemical sub-model successfully simulated most water column and sediment variables. A good model fit was also found between predicted and observed white seabream (Diplodus sargus) growth data over a production cycle. In order to optimize fish production, different management scenarios were analysed with the model (e.g. increase stocking densities, decrease/increase water exchange rates, decrease/increase feeding rates, decrease phosphorus content in fish feeds, increase food assimilation efficiency and decrease pellets sinking velocity) to test their effects on the pond environment as well as on fish yields and effluent nutrient discharges. Scenarios were quantitatively evaluated and compared using the Analytical Hierarchical Process (AHP) methodology. The best management options that allow the maximization of fish production while maintaining a good pond environment and minimum impacts on the adjacent coastal system were to double standard stocking densities and to improve food assimilation efficiency.
authors.affiliation: Portuguese Institute for the Ocean and the Atmosphere (IPMA), Avenida 5 de Outubro, s/n. 8700 - 305 Olhão, Portugal. Electronic address: dalilaserpa@yahoo.com.
authors.forename: Dalila
authors.initials: D
authors.lastname: Serpa
authors.forename: Pedro
authors.initials: P
authors.lastname: Pousão-Ferreira
authors.forename: Miguel
authors.initials: M
authors.lastname: Caetano
authors.forename: Luís
authors.initials: L
authors.lastname: Cancela da Fonseca
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Dinis
authors.forename: Pedro
authors.initials: P
authors.lastname: Duarte
mesh_terms: D000821:Animal Feed; D000818:Animals; D017756:Aquaculture / Q000379:methods* / Q000592:standards; D004777:Environment; D008962:Models, Theoretical; D021541:Sea Bream / Q000254:growth & development* / Q000502:physiology
keywords: Ecological modeling; Environmental impacts; Fish farming; Management; Sediment quality; Water quality