Freshwater pearl mussels are among the most endangered animals in the UK, with populations declining from millions to thousands. Their conservation has indirect welfare benefits for riverine species.
The welfare status of freshwater pearl mussels is uncertain — bivalves likely lack the neural complexity for conscious experience. However, their conservation has indirect welfare significance: pearl mussel rivers require the highest water quality standards, protecting the salmon and trout populations whose welfare is clear. The conservation of rare habitats like pearl mussel rivers benefits the entire riverine community including species with obvious welfare status. The illegal poaching of mussels for their occasional pearls is both ecologically destructive and legally prosecutable.