Blue mussels are farmed in large quantities in suspended longline systems, with growing interest in their capacity for pain and suffering raising welfare questions about harvest and handling practices.
The welfare status of mussels remains genuinely uncertain. Current scientific evidence suggests bivalve molluscs are unlikely to have the neural architecture necessary for conscious pain experience, but this cannot be completely ruled out. Mechanical harvest methods cause tissue damage and mortality in a proportion of animals. Air exposure during transport and grading may cause physiological stress responses in mussels. The precautionary principle suggests that if there is any possibility of suffering, minimizing unnecessary harm is appropriate. From a welfare standpoint, mussels represent a relatively low-risk animal protein source compared to vertebrates, but continued research into their sentience is warranted.