Environmental impacts and food loss and waste in the U.S. aquatic food system

Abstract

Aquatic food systems support global food and nutrition security, livelihoods, and economies, but put significant environmental pressure on the planet. The United States (U.S.) is the world’s fourth largest consumer and the largest importer of aquatic food, which makes it a good case for studying aquatic food systems. Here, we estimate the energy use, greenhouse gas emissions (GHGe) and blue water use by species, production method, product form, and stage of the U.S. supply chain, while accounting for trade and food loss and waste. We identified wide variation across species for energy use (40.2 to 259.1 MJ/kg), GHGe (3.7 to 22.2 kg CO2 eq/kg), and blue water use (15.8 to 1,851 l/kg). Capture fisheries and aquaculture on average used similar amounts of energy per unit of edible aquatic food; however, aquaculture emitted 54 % more GHGe and consumed 784 % more blue water than capture fisheries, due to the high GHGe and blue water intensity of aquaculture feed. Products with the lowest energy use were canned, fresh, and frozen sockeye salmon, frozen pollock, and frozen catfish. Products with the lowest GHGe were canned, fresh, and frozen sockeye salmon, frozen pollock, canned and frozen tuna, and frozen Atlantic salmon, All wild caught species had significantly lower blue water use impacts than farmed products. The production stage had the largest environmental impacts, but measuring production alone would miss 64 % of the energy, 36 % of the GHGe, and 21 % of the blue water used in the remainder of the supply chain. The processing stage was an important contributor to resource use for species with energy and water efficient production practices. Aquatic food in the U.S. supply is lost and wasted at an overall rate of 23 %; lost and wasted seafood contains 22 % to 24 % of the embodied energy, GHGe, and blue water in aquatic food systems. Compared to findings identified in the literature, aquatic foods in this study were lower in GHGe than beef, had a range of GHGe that extended above and below pork and poultry, and had higher GHGe than most legumes, and nuts. Estimating the environmental impacts and food loss and waste in the U.S. aquatic food system can help identify opportunities to enhance sustainability and resilience and support science communication about lower-impact foods and dietary patterns.