Freshwater Mussels: The Klamath Basin’s Shelled Little Heroes

A healthy river is crucial for one of the smallest members of the Klamath.


The Klamath River is home to many aquatic and amphibious animals that make up an intricate, interdependent ecological community. Various salmon and trout species, green sturgeon, and river otters are some of the more recognizable critters that inhabit the Klamath. But it’s some of the lesser-known characters that are just as crucial for the Klamath River’s biodiverse ecosystems. In today’s post, we’re highlighting one of the Basin’s little shelled heroes: The freshwater mussels. The Klamath River and its tributaries are home to several species of freshwater mussel. While often overlooked, these animals play a critical role in maintaining a healthy river ecosystem and have historically been an abundant, dependable source of sustenance for human and animal populations alike.

In addition to being a crucial food source for Klamath River denizens, freshwater mussels also serve as a natural filter for the river’s water. As bivalve mollusks, freshwater mussels draw water into their bodies to collect food and then expel that same water with significantly less particulate and potential pollutants. According to the  National Park Service, this serves a crucial function as freshwater mussels—specifically western pearlshell mussels—“ make one of the best ‘canaries-in-the-coal-mine’ for measuring water quality and watershed health ,” and have been used by biologists to monitor environmental conditions throughout numerous watersheds. Rivers with declining western pearlshell populations are often experiencing some sort of ecological or environmental disturbance and, due to the species’ sensitivity to a wide range of changes in the environment , their health serves as a valuable indicator of overall river health.

Freshwater mussels have also served as a valuable resource for Klamath River indigenous peoples until very recently . Unfortunately, several decades of declining freshwater mussel populations have made the Klamath River Basin’s mussels impracticable as a food source. A long-valued species of animal has all but disappeared from the indigenous diets and crafts.

The western pearlshell mussels also serve as indicators of river health in another way: the status of trout populations. Mussel larvae often attach themselves to certain trout species that, via migration and spawning, spread the developing mussels throughout the river system. When trout populations decline, and when their ability to move throughout a watershed is inhibited, western pearlshell populations are impacted accordingly. The freshwater mussel is a pertinent example of the multitudinous species of flora and fauna that call the Klamath River Basin home. Though astoundingly diverse, they share one common defining trait: dependence on the health and stability of the other species that they live amongst. When one species is affected or disrupted, all its neighbors are impacted, which is why the future of freshwater mussels rest with a healthy and restored Klamath River.