One of the most common questions we get from people about Johnson Creek is, “Are there fish in there?” Longtime watershed residents talk about a time when salmon were so plentiful in the creek that you could “walk across their backs.” After decades of perception of the creek as a dumping ground, however, most people seem skeptical that there’s much living in it. So, what’s the reality?
We know from past shock surveys done in Johnson Creek (using low electrical current to temporarily stun fish and record what’s found) that native, warm-water-tolerant fish like sculpin and minnows are the most common finds, but small numbers of coho (and more rarely Chinook) salmon, steelhead/rainbow trout, and cutthroat trout also persist. JCWC’s annual volunteer fall salmon surveys regularly record sightings of adult coho, including 11 in Crystal Springs this past year! We also get occasional calls from people who observe large fish in the creek; sometimes these are salmonids, other times they might be other species like large-scale suckers or pikeminnow.
Sometimes, we see salmon in the creek when we’re looking for something else: We do regular summer sampling for aquatic macroinvertebrates in a couple of locations on lower Johnson Creek, and have observed adult spring Chinook salmon during these efforts in each of the last two summers. This spring, while surveying for garlic mustard in Gresham, JCWC interns came across the carcass of an adult steelhead (pictured), just downstream of SE Hogan Rd.
If we’re seeing salmonids “by accident” at both ends of the watershed, where else might they be that no one knows about? One way to find out is with eDNA technology, which detects genetic material from sloughed-off scales, feces, and other biological “leavings.” This has been especially useful to document the success of fish passage projects in the watershed, which remove or retrofit barriers such as dams and undersized culverts. eDNA sampling shows that salmon and trout–undetected above the barrier pre-project–are utilizing newly-available reaches of the creek after these projects are completed. So, yes, there are fish in there; yes, some of them are salmon and trout; and yes, efforts to improve and increase habitat for them are working!
