Freshwater mussels are among the most endangered animal groups globally, with habitat degradation causing mass die-offs.
While the sentience of freshwater mussels is uncertain, the catastrophic welfare and ecological losses from their mass die-offs are clear. Millions of individual animals die during drought and pollution events in ways that likely involve some form of physiological distress. Their role in river ecosystem function means their loss cascades through the welfare of fish and other species dependent on clean water.