Towards cleaner aquaculture: assessing the environmental performance of meagre (Argyrosomus regius) fed with insect meal (Hermetia illucens)

The growing demand for sustainable aquafeeds has prompted interest in alternative protein sources to reduce reliance on fishmeal (FM), a high-impact ingredient linked to overfishing. Hermetia illucens meal (HM) offers promising nutritional and environmental characteristics, however, few studies have assessed its environmental sustainability when integrated into real-world aquaculture systems, and none has evaluated its application in meagre ( Argyrosomus regius ) farming through a Life Cycle Assessment (LCA). Therefore, this study provides the first LCA of meagre farming fed with diets containing increasing levels (10%, 20%, 30%) of HM as a partial replacement for FM. The analysis covers the entire production chain, from insect rearing to fish growth, using a cradle-to-farm gate approach and a functional unit of 1 kg of fish weight gain. Results reveal complex environmental trade-offs: while higher HM inclusion (30%) reduces impacts compared to the control diet in categories such as ozone depletion (−45%), particulate matter (−25%), and net primary production use (−40%) per kg of feed, it also leads to increased impacts per kg of fish due to reduced feed conversion ratio. Moderate inclusion levels (10–20%) deliver a more balanced profile, improving human toxicity and nutrient related categories without significantly increasing climate or resource-related impacts. The study highlights the importance of optimizing inclusion rates to balance environmental gains with production performance. It also underscores the value of an LCA-based approach to capture trade-offs across multiple impact categories and avoid burden shifting. Overall, these results indicate that moderate inclusion levels can offer environmental advantages in meagre farming, while emphasizing the need for additional research on industrial scale-up and circular feedstocks.