Valorisation of gourmet shellfish waste for sustainable artificial reef construction

Abstract

[Abstract] Galicia (northwest Spain) is internationally recognised for its gastronomic heritage, particularly for the use of pectinid bivalves such as scallops (Pecten maximus), which are central to the menus of Michelin-starred restaurants. However, the consumption of these delicacies generates significant amounts of shell waste. This study explores a novel circular economy approach by repurposing this waste as a component in eco-concrete for artificial reef construction, linking haute cuisine with marine ecosystem restoration. A survey conducted among Michelin-starred chefs confirmed the widespread and consistent use of locally sourced scallops, making their shells a reliable material stream. Laboratory analyses demonstrated that concrete mixtures with 20 % scallop shell aggregate maintain comparable compressive strength to standard formulations, improve water absorption resistance, and show stable alkalinity levels. A multi-criteria analysis ranked scallop shells from Arousa as the most effective option, combining technical performance with waste valorisation potential. These findings suggest a scalable model that connects gastronomy, sustainability, and coastal regeneration in a region heavily reliant on both food and marine economies.