Flexing Our ‘Mussels’: Volunteers Help Save Over 2,500 Freshwater Mussels During Salvage on Oxbow Conservation Area

By Emily Davis

A freshwater mussel happily situated in gravel in the bottom of a stream, filtering water. Photo by Marie Fernandez, USFWS. From "Freshwater Mussels of the Pacific Northwest"

If you’ve walked along the banks of the Middle Fork John Day River while fishing or boating and looked carefully, chances are you’ve seen piles of pearlescent freshwater mussel shells: remains of an otter or muskrat picnic. But few people have seen freshwater mussels alive underwater, and even fewer know anything about these mysterious creatures.  Here in the Western U.S., freshwater mussels are severely under-studied, but we do know that, like their aquatic neighbors salmon and steelhead, they are experiencing a drastic decline in many places, including the Middle Fork John Day.
 
Big river restoration projects, like the Oxbow Tailings Restoration Project on the Oxbow Conservation Area, are meant to improve conditions for native fish and mussels alike. These projects can involve drastic measures like de-watering the old channel to route water into the new channel; or using heavy equipment to re-shape an existing area by digging. This can put river dwellers, particularly those that can’t move far on their own, in a pickle. Restorationists try to save as many lives as they can by collecting and moving animals to new homes that won’t be dewatered or disturbed during the course of the project.  This type of operation is called a ‘salvage.’ Fish salvages are most common, and mussels are often forgotten. The good news is that freshwater mussels are starting to get more attention from stream biologists and restorationists. As they do, efforts to save mussels before beginning big earth-moving river restoration projects are becoming more common.
 
Why should we bother to save these un-charismatic creatures? After all, a freshwater mussel’s main skill set may appear to be impersonating a rock. In fact, mussels play a key role in stream and lake habitats across the globe.

Freshwater mussels are filter-feeders: they hang out on the bottom of rivers, streams and lakes and pump water into their bodies, straining out tiny bits of food as they do so. One mussel can filter several gallons of water per day, so together, the thousands of mussels in one mile of river contribute mightily to cleaning water and clearing it of parasites and pollutants. By drawing particles out of the water and excreting them, mussels make nutrients available to other bottom-dwelling animals. Like earthworms in a garden, mussels help aerate riverbottom sediments. Mussels are also an important food source for animals like raccoons, muskrat and otters. Some species, like the Western Pearlshell—found here in the Middle Fork— can live for nearly 200 years: imagine how much water a centenarian mussel may have filtered in its lifetime! Mussels are also an important traditional food for indigenous peoples, including the Confederated Tribes of Warm Springs.
 
As the fifth and final phase of the Oxbow Tailings Restoration Project kicked into high gear a few weeks ago, Tribal biologists prepared to conduct a freshwater mussel salvage. Over 30 volunteers from partner agencies ODFW, Malheur and Umatilla National Forests came out to assist with the effort. 95% of the volunteers had never worked with freshwater mussels before, so it was an excellent opportunity to get acquainted with these important mollusks.
 
Crew members donned wetsuits or drysuits, snorkels, and stream boots, and climbed into the river for a crash course in mussel ID. Within just six hours, the teams of volunteers had removed over 2500 mussels from the riverbed in the salvage zone—an astounding number in less than a mile of river. Because it was too hot to continue working that day, we held the mussels overnight in a walk-in cooler, where they stayed moist and cool.

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The following day, another crowd of eager volunteers helped “plant” the mussels into their new home, a gravel-bottomed stretch of river just a few kilometers upstream of the restoration salvage area. With so many helping hands in the water, the impossible-seeming task of individually relocating 2500 mussels one-by-one was accomplished in just three hours. Sarah Gaulke, from the Malheur National Forest, had this to say about the experience: “It was great working together with all the partners to help out this project. I also enjoyed being able to use my muscles to help the mussels!”
 
When the mussel salvage was over, volunteers left the salvage zone with a new appreciation for these amazing animals; and thousands of mussels left the salvage zone with their lives.  
 
Want to learn more about the amazing freshwater mussel? Planning a restoration project and curious about how best to organize a successful mussel salvage? Visit http://www.xerces.org/western-freshwater-mussels/ to read up on these humble creatures and what you can do to help protect them.