Tryon Creek is one of the major remaining free-flowing tributaries of the Lower Willamette River. New research shows just how healthy it is for cutthroat trout, and that’s important for the future of trout as well as for prospects to restore salmon to Tryon Creek.
The primary obstacle to restoring salmon to the urban watershed is a 400-foot culvert underneath Highway 43 near the confluence with the Willamette River. A conduit for water, it is a barrier for fish. Environmental Services, in concert with partners including the US Army Corps of Engineers have plans to remove that culvert and replace it with a wider, shallower passageway that will allow native and migratory fish like salmon and lamprey to reach the cool clean waters of Tryon Creek – and the high quality spawning and rearing habitat the creek offers.
Biologists use a seine net to survey fish below the Highway 43 culvert of Tryon Creek.
Now the new study adds to the body of knowledge showing just how healthy Tryon Creek habitat is for fish. Published in the journal Urban Ecosystems by Environmental Services scientist Melissa Brown and colleagues at the US Fish and Wildlife Service, the research compares the health of urban trout in Tryon Creek to non-urban populations elsewhere in the region. The findings show that the health of coastal cutthroat trout in this urban waterway is comparable to that of cutthroat trout in 35 more pristine rivers and streams throughout the Columbia River basin and northern California. That research tells us that there is carrying capacity in the stream for migratory salmon, such as chinook, coho and steelhead trout, says Brown.
A cutthroat trout is measured to help biologists assess the fish population's health.
As for plans to remove the Highway 43 culvert and replace it with a better passageway: Congress authorized funding for it and additional Healthy Willamette River projects last session as part of a package sponsored by the US Army Corps of Engineers. Next steps, which are underway, call for Congress to allocate the dollars that would allow the package of restoration projects to be realized.
Environmental Services is looking forward to working with the US Fish and Wildlife Services again to assess population dynamics in the future after native, migratory fish start returning to historic habitat once a new Highway 43 passage is built.
P.S. The Tryon Creek watershed is closed to fishing.