Anodonta mussel shell at Union Manor- note the teeth marks. Native freshwater mussels are a food source for many mammal species in the watershed such as muskrat, river otter, mink, raccoon. By Patrick Norton, CSP volunteer
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).
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).
Volunteer Jim takes a swim. No mussels recorded at this location. Westmoreland Park, July 10 2015
Due to the sighting of an adult Chinook salmon (female) downstream a few days prior we were not allowed to hand-dredge in the sediment to locate mussels. Despite this we found one juvenile mussel (that was large enough to have been living in the sediment for the last one or two years) and two adult mussels at the downstream extremity of the park.
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.
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.
Aquatic Conservation Program Director for Xerces Celeste Mazzacano instructs volunteers at Westmoreland's Union Manor. July 13 2015
On Monday, 27 of us surveyed the creek at Westmoreland's Union Manor. Before surveying for mussels at Union Manor we did a visual survey for any adult salmon that might be using the creek there. When we had assured ourselves that there were none we proceeded, and had permission to use wire-mesh dredge nets and grope in the sediment by hand. This was a very good thing, since at this location the sediment is deep and the creekbed is covered in places by aquatic plants.
CSP members Mary Federoff and Mary Ann Schmidt, Xerces staff member Michele Blackburn, CSP'er Bob Federoff, and an unidentified volunteer survey for mussels at Union Manor. July 13 2015
We found 2,931 live native Anodonta mussels in 20 transects at the Union Manor reach, of which 86 were previously tagged individuals. The ratio of tagged mussels to tagged shells (deceased) gave a survival ratio of 96.5%, which shows that the relocation protocol works and that the conditions at Union Manor are very suitable for mussels.
Volunteer Tom, yours truly, and Deb Espesete with Anodonta mussels, both with numbered Floy tags (the mussels, that is). Union Manor July 13 2015
All in all, and despite a few blue lips and chattering teeth, we had a very good time and were quite happy with the results. Look to our News/Events page in May and June of next year for details on the 2016 mussel survey.
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!
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!
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