Main challenges for measuring the sustainability of the marine ingredients industry: a systematic and critical review

The marine ingredients (MIs) industry is essential to the aquaculture sector, mainly providing fishmeal and fish oil to support animal feed and human nutrition. The exponential growth of aquaculture and the heavy reliance on finite marine resources pose significant sustainability challenges and highlight the need for more comprehensive and regionally adapted metrics beyond current Life Cycle Assessment (LCA) indicators and non-conventional LCA metrics. In this systematic review, we analyzed 48 literature studies that focus on the sustainability of MIs using rigorous criteria for data quality and indicator relevance under the Prisma methodology. Our findings indicate that the studies that are mainly based on conducting an LCA provide valuable insights into environmental performance, but are hindered by inconsistent metrics, limited data availability, and a lack of integration of economic, nutritional, and ethical dimensions in the sustainability analysis. Such limitations can lead to underestimate critical issues such as biodiversity loss, overfishing, habitat degradation, or the impact of illegal fishing, while overemphasizing short-term efficiency measures, like feed conversion ratio, or environmental impacts such as global warming. Additionally, emerging novel proteins and alternative uses for fish-derived byproducts, ranging from direct human consumption to high-value applications (bioactive compounds, cosmetics, etc.) to lower value products (like biofertilizers), remain largely unexplored, given the absence of holistic and flexible assessment tools. Thus, the presence of unregulated contaminants (including additives, antibiotics and microplastics), are not yet adequately addressed in most MIs studies, despite some recent methodological advancements. This review proposes the adoption of novel metrics, the standardization of assessment methods and the integration of multi-criteria decision analysis for LCA practitioners to better capture the complex and multifaceted challenges of MIs production, covering the way for more robust and reliable sustainability assessments within the aquaculture industry.