The keen observer may have noticed that the Steigerwald Reconnection Project involves dewatering Gibbons Creek. So a logical question is, “What happens to all the fish and other aquatic species already living in the Creek?” I’m excited to answer that for you, and don’t miss the video at the end of this post!
Before we could start active construction on a creek like Gibbons, we had to take a series of intricate steps to protect the fish and other species that live there. Realigning and restoring the creek requires dewatering the area using cofferdams and pipes, but before that step it is important to move the fish from the portion of the creek that is being impacted to somewhere else.
This process is know as “fish salvage” by those who do this work. For the Steigerwald Reconnection Project, this effort was led by Kim Gould from Stillwater Sciences. Kim and a team of staff from Stillwater, U.S. Fish & Wildlife Service, Lower Columbia Estuary Partnership, and LKE Corporation performed the fish salvage over the course of several days in July, 2020.
The fish salvage crew, seen here in their bright orange vests, helmets, and masks, are catching and documenting the critters they find with nets, buckets, and phones.
Kim gave everyone a thorough review of the process before we took our first steps into the cool creek waters. We start early in the morning each day and try to wrap up before the late afternoon heat kicked in. The cooler air temperature is better for the cold water fish we are catching – and it’s more comfortable for us, too.
First, we sweep with seine nets and dip nets, removing as many fish as possible. After that technique, we use electrofishing equipment, which gently stuns the fish. This also helps find fish hiding or in hard to reach places. The fish typically are not injured and are quickly netted and placed in cool containers of water with a bubbler to maintain oxygen levels. Fish are counted, identified by species, and released in a shady, cool section of Gibbons Creek located upstream of the work area with block nets preventing their re-entry.
We continued searching for fish until we captured so few that we could conclude that the vast majority of them had been removed.
A wide variety of fish and aquatic species were found during the fish salvage, including the speckled dace pictured in this net.
The 800-foot length stretch of Gibbons Creek that we de-fished was quite productive. We found:
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1,388 lamprey (both Pacific and Western Brook)
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365 juvenile coho salmon
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38 cutthroat trout
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Sculpin
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Three-spined stickleback
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Dace
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A small cluster of three Oregon floater mussels
And why do all this for Gibbons Creek? Decades ago, the creek’s channel was ditched, leaving it as a straight run with little appropriately-sized gravel and a very limited amount of wood that make good habitat for salmon. The banks were overrun with English ivy and Himalayan blackberry and many of the trees along its banks had been overwhelmed and killed by the ivy.
Once construction is complete the new, meandering channel will provide greater habitat opportunities for salmon, including wood habitat structures, introduced streambed gravels, constructed riffles and pools, and a broad floodplain that will absorb and disperse high water events. And over time, new riparian plantings of various native trees and shrubs will replace the streambank shade lost to construction.
Check out a video about the fish salvage efforts: