Investigating the environmental sustainability of a seabass and seabream aquaculture system in Portugal based on life cycle and nexus approaches

Aquaculture plays an essential role in supplying animal-source food and protein worldwide, in this way contributing to several sustainable development goals. Notwithstanding this, the aquaculture sector's long-term environmental sustainability is a major concern due to overall environmental impacts. To date, and to the best of the authors' knowledge, assessments of aquaculture systems in Portugal from an environmental perspective, and the nexus between resource consumption and nutrition issues, are still lacking. This study bridges this gap by analysing an aquaculture system in Portugal in a comprehensive manner by applying and combining life cycle assessment and resources–protein nexus approaches. The overall results highlight feed as the main factor responsible for the total impact in all impact categories selected, ranging from 74 % to 98 %. Climate change impact results in 2.88 kg CO2-eq per kg of medium-size fish (functional unit). The resources–protein nexus shows that 504.1 MJex is needed to obtain 1 kg of edible protein, with a high dependency on non-renewable resources (59 %), mainly oil by-product fuels used in feed production. After identifying environmental hotspots, potential strategies to be adopted such as resource consumption reduction, eco-certification and ecosystem-based management are suggested, in this way ensuring long-term aquaculture production and environmental sustainability.