Freshwater pearl mussels are one of the most endangered species in Britain, requiring extremely clean, fast-flowing rivers. Pollution, siltation, and the loss of host salmon have caused catastrophic population decline.
As sentient invertebrates with complex physiologies, freshwater pearl mussels warrant welfare consideration. Siltation suffocates juveniles buried in river gravels. Pollution from agricultural runoff and septic tanks impairs filter feeding and causes stress. The extreme longevity of this species means that death of large individuals represents the loss of century-long lives.