title: Life cycle assessment of aquaculture systems-a review of methodologies.
abstract: OBJECTIVE
  As capture fishery production has reached its limits and global demand for aquatic products is still increasing, aquaculture has become the world's fastest growing animal production sector. In attempts to evaluate the environmental consequences of this rapid expansion, life cycle assessment (LCA) has become a frequently used method. The present review of current peer-reviewed literature focusing on LCA of aquaculture systems is intended to clarify the methodological choices made, identify possible data gaps, and provide recommendations for future development within this field of research. The results of this review will also serve as a start-up activity of the EU FP7 SEAT (Sustaining Ethical Aquaculture Trade) project, which aims to perform several LCA studies on aquaculture systems in Asia over the next few years.
  
  
  METHODS
  From a full analysis of methodology in LCA, six phases were identified to differ the most amongst ten peer-reviewed articles and two PhD theses (functional unit, system boundaries, data and data quality, allocation, impact assessment methods, interpretation methods). Each phase is discussed with regards to differences amongst the studies, current LCA literature followed by recommendations where appropriate. The conclusions and recommendations section reflects on aquaculture-specific scenarios as well as on some more general issues in LCA.
  
  
  RESULTS
  Aquaculture LCAs often require large system boundaries, including fisheries, agriculture, and livestock production systems from around the globe. The reviewed studies offered limited coverage of production in developing countries, low-intensity farming practices, and non-finfish species, although most farmed aquatic products originate from a wide range of farming practices in Asia. Apart from different choices of functional unit, system boundaries and impact assessment methods, the studies also differed in their choice of allocation factors and data sourcing. Interpretation of results also differed amongst the studies, and a number of methodological choices were identified influencing the outcomes.
  
  
  CONCLUSIONS
  Efforts should be made to increase transparency to allow the results to be reproduced, and to construct aquaculture related database(s). More extensive data reporting, including environmental flows, within the greater field of LCA could be achieved, without compromising the focus of studies, by providing supporting information to articles and/or reporting only ID numbers from background databases. More research is needed into aquaculture in Asia based on the latest progress made by the LCA community.
authors.affiliation: Institute of Environmental Sciences (CML), Department of Industrial Ecology, Leiden University, 2333 CC Leiden, the Netherlands.
authors.forename: Patrik J G
authors.initials: PJ
authors.lastname: Henriksson
authors.affiliation: Institute of Environmental Sciences (CML), Department of Industrial Ecology, Leiden University, 2333 CC Leiden, the Netherlands.
authors.forename: Jeroen B
authors.initials: JB
authors.lastname: Guinée
authors.affiliation: Institute of Environmental Sciences (CML), Department of Industrial Ecology, Leiden University, 2333 CC Leiden, the Netherlands.
authors.forename: René
authors.initials: R
authors.lastname: Kleijn
authors.affiliation: Institute of Environmental Sciences (CML), Department of Industrial Ecology, Leiden University, 2333 CC Leiden, the Netherlands.
authors.forename: Geert R
authors.initials: GR
authors.lastname: de Snoo
keywords: Aquaculture; Fish; Food; LCA; Life cycle assessment; Review; Seafood