Native salmonids (Rainbow/steelhead trout, Bull Trout, Dolly Varden) populations in the upper Skagit River have a complex evolutionary past shaped by geology, hydrology, and human actions. In our latest research study funded by City Light, we’re using genomic tools to unravel the phylogenetic biogeography of Rainbow and Bull Trout in the upper Skagit River basin. Meaning, do the genetic relationships among fish correlate with the geologic history of the North Cascades Range? How did past glaciers and altered connections among rivers influence their genetic connectivity? How have more recent hatchery introductions affected their genetic diversity? Stay tuned as we trace these trout’s genetic identities to better understand and conserve these important species in their native habitats.

Our recently completed genetic assessment found the native salmonids in the upper Skagit River were distinct from fish below the lowest Dam at the Skagit Gorge. This work motivated the current study we are leading to prove whether the distinctiveness is related to quite recent human activity or ancient connectivity among rivers that no longer exist. Currently, our team is meeting with project collaborators to establish the key questions of interest and how those questions are to be answered. Importantly, there is consensus on the approach among colleagues involved. 

While the study’s purpose is academic in nature, the information is envisioned to inform City Light’s management responsibilities in the Basin. Further, with the inclusion of anadromous (ocean going) salmonid reintroduction as a potential policy action, understanding the origins of fish present and the genetic implication of non-volitional passage is important for sound stewardship. 

Working on projects related to the upper Skagit River for City Light has been rewarding from both a scientific and business standpoint. We thank everyone that has been involved with this work, HDR for bringing us on as technical experts and City Light for supporting us. Look out for future project updates.