On July 10 and 13 2015 volunteers led by biologists from the Xerces Society for Invertebrate Conservation (partnering with the CSP) waded in Crystal Springs Creek and surveyed for freshwater mussels. This year was the second annual survey following the restoration of the creek at Westmoreland Park in 2013, when we rescued over 700 mussels from the park and relocated them upstream to the Union Manor property.
The purpose of the followup surveys is to discover the effect of salmon habitat restoration on native mussel populations in streams as well as the effect on invasive Corbicula clams. Additionally, we counted tagged mussels at Union Manor to determine survivorship rates of relocated individuals.
On Friday the 10th twenty-five of us waded in the creek or stood on shore at Westmoreland Park to survey the creekbed and record data. In most sections we were only knee-deep, but there were a couple of deep pools (see photo below).
The two adults were probably occupying the pool of water where the diversion channel reentered the creek during the restoration project, and so were not deprived of stream water during the restoration. Had we been able to use dredge nets or grope with our hands at the park we would likely have discovered more juvenile mussels, including the thumbnail-sized 'young-of-the-year' which tend to burrow in the substrate. Alas, Chinook salmon are also protected species and we needed to be careful not to direct large plumes of sediment downstream when they were in the area.
Special thanks to The Xerces Society for Invertebrate Conservation for their expertise and hard work, and to the City of Portland, Union Manor, Metro, East Multnomah Soil and Water Conservation District, and the Oregon Watershed Enhancement Board for their continued support. And most of all, thank you to the volunteers for making these surveys a success!