Sustainable aquafeed? The devil is in the detail

Aquaculture is essential to meet the increasing demand for nutritious seafood. Aquafeed input represents most of the environmental impact and production cost, formulations consist of a combination of marine and plant-based ingredients. Driven by economic and sustainability incentives there has been a shift from marine ingredients towards plant-based ingredients, and smaller inclusions of (fish) by-products and novel feed ingredients. We applied Index Decomposition Analysis to assess the changing environmental impact from 2000 to 2020 for the European (European Economic Area (EEA) + United Kingdom (UK)) aquaculture industry. In this period the total production of the main produced species in Europe grew from 1.15 million metric tonnes (MMT) in 2000 to 2.17 MMT in 2020. On an industry level we find a substantial increase in Global warming (314%), Land use (594%), Water consumption (236%), Marine eutrophication (630%) and Freshwater eutrophication (468%), while Wild Fish Use was reduced by 13%. Considering an efficiency metric per kg fish produced, Wild fish use was reduced by 59% while Global warming (103%), Land use (336%), Water consumption (65%), Marine eutrophication (285%) and Freshwater eutrophication (167%) increased substantially. These changes are mostly attributed to the substitution of marine ingredients by plant-based ingredients shifting pressures from marine to terrestrial impacts. While by-product utilisation for marine ingredients contributed to a lower reliance on marine ingredients without significant trade-offs. We demonstrate that use of two terrestrial ingredients, soy protein concentrate, and rapeseed oil, have had a disproportionate and detrimental impact on the environmental footprint, emphasising the need for comprehensive and consistent sustainability assessments of aquafeed and aquaculture production.