This reminds me of the Coho that return to the upper Willamette (Tualatin and yamhill rivers). These fish are not truly native according to ODFW. They began planting them in the 1920's and stopped in the 40's. They have managed to reproduce and on some years thrive over the past 70 years without any help. In fact, both of those rivers mentions have been strait up $hitholes for many years. Last 2 years there have killer returns. ODFW considers them evasive species...... Tuff goddamn fish either way.