Northeast Atlantic blue mussel aquaculture using different technologies produces low-impact food despite shell formation emissions

Abstract Understanding how production setting and technique differences impact environmental performance of blue mussel aquaculture is important, before it expands to meet growing demand for sustainable seafood. Here we present combined results of LCA and biogenic CO 2 release modelling from diverse mussel farming operations in the northeast Atlantic. Results of this study are based on a large dataset on GHG emissions of blue mussel aquaculture including those from shell formation. Mussels represent a food category with great promise for sustainable healthy food production but with limited LCA studies which generally exclude shell formation emissions. Overall, farms reseeding mussels had lower greenhouse gas, but higher eutrophying emissions and land use, compared to farms that did not reseed their mussels. The higher land use documented for reseeded mussels was due to cotton socking used for reseeding. Though fossil fuel use dominated climate impacts, these can be rivalled by biogenic CO 2 emissions. Doubled material lifetime, halving harvest losses and electrification led to 40–80% greenhouse gas emission reductions, while minimising cotton socking reduced eutrophication and land use. Even under a worst-case biogenic CO 2 emission scenario, climate impacts of farmed mussels are a small fraction of those from other seafood sources or livestock.