Freshwater pearl mussels and other native freshwater bivalves provide ecosystem services while their welfare may be affected by water quality, siltation, and salmon host fish availability.
Freshwater pearl mussel welfare sits at the uncertain frontier of invertebrate sentience research, where philosophical caution about the welfare significance of their experience must be balanced against the strong conservation obligation to protect one of the world's most endangered bivalve species. Whether freshwater pearl mussels experience welfare-relevant states is genuinely unknown - their nervous systems are far simpler than those of fish or crustaceans, and the evidence for subjective experience in bivalves is extremely limited. However, their ecological role as water filterers and the indirect welfare benefits their presence provides to the river ecosystem - including cleaner water for fish and invertebrates with clearer welfare relevance - justifies protection regardless of mussel sentience uncertainty. Practical welfare and conservation overlap completely in their management: improving river water quality, preventing siltation, protecting juvenile salmon host fish populations, and managing river flow regimes all benefit pearl mussels while also improving conditions for species with clearer welfare needs. The individual longevity of pearl mussels - with survivors exceeding 130 years - makes the potential loss of each individual particularly significant from both welfare and conservation perspectives.