So to maintain a "quality" brook trout fishery in your mind we should let a naturally evolved unique species die out in one particular stream? Why not, the brook trout have expatriated all the Willow Ck bull trout anyway, just one more stream with no cutthroat that's all. That only makes 9 -10 more streams with no natives that I've personally witnessed...
Lobby to turn Cataract into a quality brook trout fishery if you're so inclined, it's historically fish barren above the falls anyway but you're gonna have to siphon about 50% of the brookies out of there if you want to maintain any size........... although it would be a good safe low cost place to stash some pure cutts in case the decline continues, can't just depend on the upper Old Man, Westcastle and Lynx