Freshwater mussels including the critically endangered freshwater pearl mussel are declining across the UK. Their welfare status and sentience are uncertain but conservation is urgent.
The welfare status of freshwater mussels is genuinely uncertain - their nervous systems are far simpler than vertebrates and whether they have subjective experience is debated. However, the precautionary principle and conservation urgency together justify protective action. The interconnection between freshwater pearl mussel and Atlantic salmon welfare is direct - each depends on the other's presence for reproduction. River restoration that benefits salmon creates the conditions for pearl mussel recovery, making these two conservation and welfare causes mutually reinforcing.