The River’s Quiet Cleaners: Passion and Purpose in Freshwater Mussel Conservation Through Habitat Restoration

Imagine stepping into the warmth of your dry suit, securing your mask and snorkel, and bracing yourself for the cold underwater world below. Everything is suddenly silent - it’s just you, the rhythm of your breaths, and the stillness of the surface. As you peer down, you see one of the many hidden gems of the river: freshwater mussels, though, to the untrained eye, they may be overlooked as simply another bed of rocks. But don’t be mistaken, their quiet presence carries much more weight, as they embody the river’s health, each mussel reflecting a flourishing underwater ecosystem. ¹

This represents a thriving and healthy freshwater mussel bed of which there are not many remaining within the rivers of the Willamette Valley. We sat down with Emilie Blevins, Senior Endangered Species Conservation Biologist and Freshwater Mussel Lead for Xerces Society for Invertebrate Conservation, to get an understanding of the role of freshwater mussels in our river ecosystems. Her summer mornings in the field often include putting on a dry suit and a snorkel to assess freshwater mussel populations and distributions, however, the populations she often sees are not carpets of mussels clinging to the riverbed but rather populations struggling to hang on. 

Fondly referred to as “the liver of the river,” freshwater mussels tirelessly filter water, trapping pollutants, and cycling nutrients, helping to sustain entire ecosystems. They live for up to 100 years burrowed in the bottom of the stream bed. Mussels are “fundamentally part of the river being completely surrounded and within the water and absorbing and filtering any pollutant that ends up in our river”, said Blevins. While this results in cleaner river ecosystems, it also means freshwater mussels are especially vulnerable to human pollution of waterways such as oil spills, agricultural runoff, or sewage. “There's not really a separation between the animal and the ecosystem as the river is them and they are the river”, said Blevins.

Western Pearlshell freshwater mussels filtering the water around them while nestled in the sediment of the river bottom. Photo credit: Xerces Society

Freshwater mussels are an indicator of river health so loss of mussel beds indicates something is wrong. The “way that we treat our rivers directly affects whether or not we will have mussels in the future”, said Blevins. Blevins has seen first hand the declining populations of freshwater mussels within the Willamette Valley, sharing the sadness she felt upon returning two years later to a previously thriving population to find “half of them dead and dying”. Although an unhappy experience, Blevins views this as a “driving force” in her work wanting to “ensure that doesn't happen anywhere else.” On the flip side, Blevins recounted fond memories of coming across the “most dense, beautiful freshwater mussel bed that [she] had ever seen” and feeling an intense desire to do all in her power to “protect it and make sure that it's still there in the coming years.” 

Moving forward in freshwater mussel conservation, Blevins hopes to see continued habitat restoration activities within the Willamette Valley that help to restore a healthy riparian zone or river bank. The roots of the plants within a healthy riparian zone create protective habitat for mussels, decreasing their vulnerabilities to changes in the power of the river. However, the construction necessary to complete a restoration project presents unique threats to freshwater mussels. To get an understanding of a recent in-stream restoration project within the Willamette Valley and its impacts of freshwater mussels, we sat down with an on the ground practitioner of restoration and conservation efforts. 

Freshwater mussels population are in decline, but we can still play a role in protecting them. If you see a mussel shell along the river, that’s a sign of life—likely a live mussel nearby. Share those observations on platforms like iNaturalist to help track and protect these vital species. For those interested in restoration involvement, explore resources on the Xerces Society website to learn how you can help safeguard mussel populations. Through combined efforts of research, restoration, and education, we can ensure that these “powerhouses of the river” have a place to thrive, reminding us of the wonder and resilience in the heart of the Willamette Valley. 

“Freshwater mussels have a foot that they extend into the bottom of the river to hold themselves in place.” (Emilie Blevins) Photo Credit: Kurt Ingeman, Assistant Professor of Environmental Studies, Linfield University

1. Video Credit: Xerces Society