Current status and future research needs on the quantitative water use of finfish aquaculture using Life Cycle Assessment: A systematic literature review.

Sustainable aquaculture is an endeavor towards increasing global food security. While access to sufficient water is key for appropriate fish farming, there are various methodological gaps when assessing quantitative water use (QWU). This study discusses the status of QWU in finfish aquaculture in depth and contributes to the understanding of the different QWU methodologies currently used in this field within the Life Cycle Assessment (LCA) framework. A systematic literature review following the Protocol, Search, Appraisal, Synthesis, Analysis, and Report (PSALSAR) methodology was conducted, to evaluate the available scientific literature (January 2009–March 2022) of LCA studies intertwined with QWU of finfish aquaculture and associated fish processing. A total of 22 articles (80 treatments) were included and classified based on their fish production systems, LCA characteristics, and aquaculture intensity (using the Aquaculture Production Intensity Scale - APIS score). Four QWU methodologies were reported: water dependence (WD, 15 studies), AWARE (3 studies), Water Footprint Assessment (WFA, 2 studies), and consumptive water use (CWU,2). Comparison of results from these methodologies is challenging due to different technical approaches assessing water use quantities. For instance, AWARE, WFA and CWU account for water consumption, whereas WD accounts for all the water reared into a system, regardless of it being returned to the sourced watershed or not. WD can be used for fresh, brackish or seawater, whereas the other methodologies account exclusively for freshwater. WD and AWARE consider only blue water, WFA includes green, grey and/or blue water, and CWU considers green and/or blue. Moreover, WD and CWU are inventory methodologies, AWARE is midpoint, and WFA can be inventory or midpoint methodology. QWU method development for aquaculture, which is a complex system with diverse water requirements, is much needed. This study highlights future research needs in QWU in aquaculture, to help standardize the QWU methodologies used in aquaculture and facilitate the implementation of water management practices for both direct and indirect water usage, which are key for achieving sustainable aquaculture.