Environmental impacts of existing and future aquaculture production: Comparison of technologies and feed options in Singapore

Abstract

In a context of global population growth and increased food demand, the development of the aquaculture industry has become essential, and aquaculture development policies have flourished. However, aquaculture is associated with various environmental impacts, such as eutrophication or climate change. It is therefore important to assess the environmental sustainability of aquaculture development, for example through the use of life cycle assessment (LCA). Yet, there is limited application of LCA to aquaculture technologies in Asian countries, where most aquaculture growth is taking place, and none of them has assessed environmental impacts of both current and future aquaculture systems. Here, we took Singapore as an example of country, which has recently developed aquaculture development strategies, and we performed a comparative LCA of eight Singaporean aquaculture production systems, thus covering all relevant existing and potential future production technologies. To do so, we built comprehensive life cycle inventories (LCI) of 8 categories of aquaculture production for four species groups in Singapore, for both 2017 and 2040. Two options of feed evolution were assessed in 2040: increasing the part of fishmeal and fish oil (FMFO) produced from trimmings and replacing FMFO by insect-based meal and algal oil. We assessed 11 environmental impact categories, including net primary production use. Overall, per unit of edible seafood produced, the production of marine fishes in sea cages near the shore and in recirculating aquaculture systems were found to be the most attractive options to limit the environmental impacts while increasing seafood production in Singapore. Freshwater fishes produced in concrete ponds were found to have the lowest impact indicator scores per ton of edible seafood produced, but these results were highly sensitive to methodological choices and it was deemed constrained by limited potential to increase its production capacity in the future. Increasing the part of FMFO produced from trimmings is found to have more environmental benefits than insect-based meal. However, the uncertainty concerning the future technologies is high, particularly for anticipating future technologies. Further research is therefore needed to refine the assessment of the potential environmental impacts of future aquaculture production systems, including focusing on novel technologies and new feed options specifically adapted to each country. Meanwhile, we recommend analysts to take inspiration from and build on the detailed LCIs developed in the current study to support assessments of aquaculture systems in other underresearched Asian countries.