Life cycle assessment of Tilapia production via conventional aquaculture and aquaponic systems

Abstract

The rapid growth of aquaculture towards global food security presents environmental challenges necessitating the adoption of sustainable practices and technologies. Aquaponics is potentially one of the Nature-based Solutions (NbS), relying on the symbiosis between fish, bacteria, and plants to create a sustainable system that enhances food and water security while purportedly reducing environmental impacts. The study assesses and compares the environmental performance of aquaponics producing tilapia and lettuce with corresponding conventional production using life cycle assessment (LCA). The results revealed that aquaponics tilapia generally performs worse than conventional production in all environmental impact categories, except for eutrophication, terrestrial ecotoxicity, and water consumption. Partially replacing fish meal with plant-based protein (e.g., soybean meal) in tilapia feed can generally reduce the environmental impact of tilapia production in both conventional systems and aquaponics. Using solar energy can improve the environmental performance of tilapia production in aquaponics. Replacing fishmeal with soybean meal in fish feed and using solar energy in fish farming can make the performance of aquaponics tilapia better than conventional production in most categories, except for terrestrial ecotoxicity and human toxicity. From the perspective of lettuce production, even after improvements, aquaponics lettuce still performs worse than conventional production across all impact categories, except for terrestrial acidification and marine eutrophication. This highlights that NbS, such as aquaponics, may not always guarantee better outcomes than conventional production systems. The trade-off between environmental benefits in certain areas and the higher energy demands highlights the challenge of adopting aquaponics as a sustainable alternative to conventional farming.