Feed From Waste: A Circular Economy Approach for Sea Urchin Aquaculture

Abstract

Marine organisms offer a vast and still underutilized reservoir of biomolecules and biomaterials with promising applications across various human sectors. Among them, sea urchins—such as Paracentrotus lividus—stand out due to their high content of biogenic carbonates, making them particularly relevant within circular economy strategies and blue growth frameworks. P. lividus is a prized delicacy in Italy and other countries; however, only the gonads (roe) are consumed, while the majority of the biomass is discarded as waste. Despite ongoing efforts to establish full-cycle aquaculture systems, the market supply in Europe remains predominantly reliant on wild harvesting, leading to overexploitation and depletion of natural populations in several regions. In this study, we explored the potential to valorize waste generated by the seafood industry, particularly the carbonate-rich test of P. lividus, by incorporating it into experimental aquafeeds. The rationale was that a biogenic carbonate source, naturally enriched with magnesium and antioxidants derived from pigments in the test and spines, could enhance both somatic and gonadal growth in cultured urchins. Results demonstrated that it is possible to formulate a stable, effective feed that supports gonad development. Moreover, feeds containing sea urchin-derived biocarbonates exhibited higher antioxidant activity compared to formulations based on commercial inorganic calcium carbonate, even when supplemented with synthetic antioxidants. These findings suggest that incorporating biogenic waste into aquafeeds not only supports sustainable aquaculture practices but may also improve feed shelf life and promote better health and performance in cultured sea urchins.