A new review of life cycle assessment studies on bivalve aquaculture, published in Reviews in Aquaculture, examines how carbon stored in shells should be counted. Researchers analyzed 31 studies from 1990 to 2024 and found no consensus on whether shell calcium carbonate counts as long-term carbon sequestration or if calcification chemistry offsets the storage. This matters for how sustainable mussels, oysters, and clams are rated. The review also shows that the biggest environmental impacts from bivalve farming come from energy use, fuel, transport, and plastic materials, not from the animals themselves. Future sustainability gains will depend on improving energy efficiency and logistics rather than changing the biology of the systems. Bivalves remain a strong option for sustainable protein, but how their carbon benefits are measured will shape future regulations and market claims.
