Exploring the genetic origins of Pacific salmon and steelhead trout that use the habitats of the Willamette River and its tributary streams in the city of Portland, Oregon.

The lower Willamette River is Endangered Species Act (ESA)-designated critical habitat for five listed salmon and trout populations in the Columbia River basin. These five genetic stocks of fish comprise the majority of salmon and trout identified using habitat in the region that extends into the City of Portland. It is well understood that migratory fish from other watersheds throughout the Columbia Basin may use habitat found in Portland. It is unclear where those fish originate, whether in Portland or in other watersheds outside the city, without genetic analysis. The National Marine Fisheries Service (NMFS), the federal agency tasked with ESA fish recovery, cites that the lower Willamette is likely to serve an additional nine listed salmonids that pass through the area during their up and downstream migrations. Our bureau's year-round watershed monitoring efforts have given us opportunities to collect fin clips for analysis of stock origin, and with a bit of biological sleuthing, we've come up with some interesting theories about how visitors from way out of town (500+ river miles) are using Portland's rivers to keep their genes in the pool.