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Abstract The global fish supply chain handles ∼179 million tons of product annually (as in 2018). Transportation and distribution are an important part of fish supply chain, as fish and shellfish are one of the largest globally traded food commodities with a trading value of ∼$153 billion in 2017. Here we show that disregarding the environmental impacts of fish transportation, either land transit or flight, neglects a noteworthy portion of total fish provisioning environmental impacts. We identified that local fish provision, considering (1) all Wisconsin counties as production points, (2) cities of Chicago, Milwaukee, and Minneapolis as consumption points, and (3) effective, semi-effective, and ineffective space heating approaches, has significantly lower environmental impacts than imported fish provision, considering flight transportation from offshore production points. Meaning the necessity to elevate local fish production capacity to enhance the environmental sustainability of fish provision is essential, despite potential elevated heating demands for cold-weather aquaculture. 

Life cycle assessment (LCA), a tool used to assess the environmental impacts of products and processes, has been used to evaluate a range of aquaculture systems. Eighteen LCA studies were reviewed which included assess- ments of recirculating aquaculture systems (RAS), flow-through systems, net cages, and pond systems. This re- view considered the potential to mitigate environmental burdens with a movement from extensive to intensive aquaculture systems. Due to the diversity in study results, specific processes (feed, energy, and infrastructure) and specific impact categories (land use, water use, and eutrophication potential) were analyzed in-depth. The comparative analysis indicated there was a possible shift from local to global impacts with a progression from extensive to intensive systems, if mitigation strategies were not performed. The shift was partially due to increased electricity requirements but also varied with electricity source. The impacts from infrastructure were less than 13 % of the environmental impact and considered negligible. For feed, the environmental impacts were typically more dependent on feed conversion ratio (FCR) than the type of system. Feed also contributed to over 50 % of the impacts on land use, second only to energy carriers. The analysis of water use indicated intensive recirculating systems efficiently reduce water use as compared to extensive systems; however, at present, studies have only considered direct water use and future work is required that incorporates indirect and consumptive water use. Alternative aquaculture systems that can improve the total nutrient uptake and production yield per material and energy based input, thereby reducing the overall emissions per unit of feed, should be further investigated to optimize the overall of aquaculture systems, considering both global and local environmental impacts. While LCA can be a valuable tool to evaluate trade-offs in system designs, the results are often location and species specific. Therefore, it is critical to consider both of these criteria in conjunction with LCA results when developing aquaculture systems. 

The environmental sustainability of aquaculture food production systems is of critical concern due to its rapid expansion as the fastest growing major food production sector in the world. Among the parameters that con- tribute to the overall environmental impacts of aquaculture marine-based protein production, aquafeed is identified as an impact hotspot. There is consequently a need to seek more environmentally sustainable aqua- feeds to mitigate the adverse environmental impacts associated with aquaculture food production. The environmental and economic sustainability of aquafeeds can be improved using two main approaches: (a) optimizing finite resources use (e.g. fish meal and fish oil), and (b) mitigating waste generation and emissions. A variety of ingredients have been previously proposed, investigated, and utilized to accomplish these strategies, while maintaining acceptable food production efficiencies. However, comprehensive evaluation of the en- vironmental sustainability of aquafeeds with respect to variable ingredients, both in terms of resource use and waste emission has not been conducted. In this work, a holistic life cycle impact assessment of twelve practically formulated and utilized aquafeeds has been performed to provide a comparative evaluation of different aquafeed's environmental impacts, con- sidering resource use (biotic resource use, water intake, and fossil fuel depletion) and emission-based impact categories (ozone depletion, global warming, photochemical smog, acidification, eutrophication, carcinogenics, non-carcinogenics, respiratory effects, and ecotoxicity). Results indicate that the investigated fish meal free diets do not, on the whole, result in a significant decrease in environmental impacts with respect to the use of biotic resources. However, if the substituted ingredients would not propose elevated impacts (e.g. blood meal), these diets can potentially lower the overall environmental impacts of aquafeed production mainly with respect to relevant emission-based indicators (e.g. global warming, eutrophication, ecotoxicity). Findings demonstrate that the investigated fish oil free diets can potentially lower the use of biotic resources. However, to prevent burden shifting, strategies to provide nutrient-rich oils with minimal energy requirement need to be undertaken.