Freshwater mussels are among the most endangered animal groups globally, and their welfare status is contested, with growing evidence for stress responses even in animals without conventional pain systems.
Freshwater mussel welfare represents the outer frontier of welfare consideration — animals whose neural architecture is so different from centralized brain-based systems that the standard welfare concepts may not apply meaningfully, yet who show environmental responsiveness that at minimum raises the question. Whether valve closure responses to threatening stimuli involve anything like experience is genuinely uncertain. The conservation case for freshwater mussel protection is entirely independent of the welfare case: they provide irreplaceable water filtration services and represent extraordinary biodiversity that has been decimated by habitat modification. For wild harvest mussel welfare, the most relevant question may be about acceptable killing methods if any level of sentience is possible — live boiling has been criticized on precautionary grounds, while rapid chilling and processing methods create less uncertainty.