LCA for open systems: a review of the influence of natural and anthropogenic factors on aquaculture systems

Abstract

Life cycle assessment (LCA) studies in the aquaculture sector have included marine fish, freshwater fish, and shellfish species within closed (CAS), semiclosed (SCAS), and open aquaculture systems (OAS). The absence of a physical boundary separating open aquaculture systems from natural ecosystems has caused complications in determining the actual environmental conditions of individual aquaculture systems and has resulted in questionable LCA impact analysis results. This paper reviews how natural and anthropogenic factors were managed in the previous LCA studies for aquaculture systems. Ten recent peer-reviewed documents on the LCA study of various aquaculture systems have been selected for content analysis. The disparities between OAS, SCAS, and CAS were outlined. Natural and anthropogenic factors were then identified and analyzed to ascertain their impact on the LCA process. Natural factors such as seasonal variations, biological interactions, and flooding were indicated in the OAS, SCAS, and CAS. For anthropogenic factors, industrial energy inputs and human activities were stated in SCAS and OAS. None of the anthropogenic factors were considered in CAS as these systems are isolated distinctly from natural ecosystems. LCA studies of the OAS have a few approaches: the development of the virtual boundary, a longer period of data collection, harmonization with other environmental management tools, and the need to diversify the LCA study in various regions. For SCAS and OAS, the interaction between the aquaculture system and flood hazards, temporal changes, dilution effects due to the seasonal variation, disease, and local anthropogenic activities can be studied further. An LCA study of OAS will be more reliable if natural and anthropogenic factors are seen as supportive variables in determining the life cycle impact analysis.