Experimental design and field deployment of an artificial bio-reef produced by mollusk shell recycling

Shellfish farming is considered a highly sustainable form of aquaculture that has developed rapidly worldwide. Unfortunately, today biological and chemical pollution of the oceans and marine waters is widespread and has multiple negative impacts on marine ecosystems, which are exacerbated by global climate changes. In addition, such impacts on fisheries and aquaculture are significant in inducing socio-economic losses. Therefore, it is necessary to develop innovative solutions to improve productivity and environmental performance in line with the blue sustainable economy (European Green Deal). However, one upcoming problem associated with shellfish consumption is shell waste and its disposal. In addition, the percentage of wasted shells destined for reuse is much lower than the one accumulated in landfills or in more or less well-managed sites. This represents a weakness of the shellfish farming sector that can only be mitigated through a project of shellfish waste recycling moving towards the circular economy, with undoubted environmental and economic advantages. In the present study, we present a possible solution for recycling clam shells coming from the waste of the fishing industry (circular economy). Indeed, three eco-friendly bio-reefs for the stabilization and implementation of marine biodiversity (blue economy) were realized using additive manufacturing technology (3D printing) for large dimensions (technological innovation). Furthermore, before deploying the reefs on the sea bottom, they were colonized with oysters to promote repopulation.