Freshwater mussels are among the most imperilled animal groups globally, with their population declines affecting river ecosystems on which many other animals depend for food and water filtration.
Whether freshwater mussels are sentient remains scientifically unresolved, but their ecosystem role for other animals with clearer welfare status is undeniable. Rivers with healthy mussel populations support fish, waterfowl, and riparian wildlife at higher densities and better health than degraded systems. The collapse of mussel populations cascades through river food webs, reducing the welfare of many clearly sentient animals dependent on the ecosystem services mussels provide. Protecting freshwater mussels is therefore a high-leverage action for animal welfare across entire river ecosystems, regardless of the direct welfare status of mussels themselves.