Freshwater pearl mussels are among the world's most endangered animals, with critically threatened populations in Scotland, Ireland, and a few rivers in England and Wales. Their welfare considerations are unusual given their status as filter feeders.
Freshwater pearl mussel welfare considerations are philosophically complex given their status as simple filter feeders. Whether they have welfare-relevant experiences in a meaningful sense is uncertain. However, their conservation significance is profound, and their role in river ecosystem health creates ecosystem welfare benefits for all species they support. Their extreme longevity means individual mussels destroyed by pollution or poaching represent centuries of growth eliminated. Conservation actions that protect pearl mussel populations serve ecosystem welfare even if individual mussel welfare is uncertain.