This article was featured in Eurofish Magazine 6 2025.
Undersized mussels used to be considered waste among mussel farmers, as they were not eligible for sale and often simply discarded. On farms on the coast of Brittany alone, these amount to between 6,000 and 12,000 tonnes, representing around 20% of the overall catch. A pioneering project by the French mussel producer’s association Cultimer is transforming the way this by-product is utilised. Based on industrial valorisation processes, the mussel waste is turned into smaller units through biological fermentation, allowing it to be used to generate methane. This, in turn, can be used as a renewable and clean energy resource. Additionally, mussel shells are repurposed as a fertilizer or as animal feed, utilising otherwise discarded materials in a closed-loop system. The project, consisting of mussel producers, local authorities, and scientific researchers, has developed a mobile processing unit that can be deployed on-site. This way, mussel farms can utilise the technology within the existing farm system, further reducing economic strain and environmental harm.
