Isolines as a new tool to assess the energy costs of the production and distribution of multiple sources of seafood

Consumer-based ocean conservation efforts focus attention on seafood that is produced in an "eco-friendly" manner. However, many species can be produced either in aquaculture operations or harvested within wild capture fisheries, and each mode of production differs in their environmental impacts as well as their energy requirements. Complicating the assessment of eco-friendly seafood is the fact that seafood is a global commodity, the suppliers of which utilize a variety of methods to distribute the product from producer to consumer (e.g. ship, truck, airplane). Like the modes of production, these various modes of distribution differ in their energy intensity. This analysis assesses the overall energy requirements of production and distribution (E_P&D) of seafood to evaluate how the energy costs of distribution influence the total energy cost of seafood produced by different methods. This paper develops the concept of energy isolines as a tool to assess E_P&D. Isolines are a graphical method to succinctly integrate multiple distance assessments so that the best sourcing option can be determined. The isolines are then used to assess how the energy cost of distribution functions as a component of the overall energy cost, and how this influences the E_P&D of a product originating from two different sources with inherently different energy costs of production. Using scallops and salmon as examples, this analysis has revealed that an "eco-friendly" seafood commodity (one produced with less energy) produced far from its destination market could have a higher total E_P&D compared to a local, less "eco-friendly" product (that takes more energy to produce). Finally, this paper evaluates strategies to minimize the overall E_P&D of seafood. Overall, further work on energy audits of seafood focused the need to maintain a global perspective to determine seafood with the lowest overall energy cost of production and distribution.