There is no self sustaining populations of trout in Taney. They may try to spawn some but it is all moot.
The Browns are the only noticable species as far as a run because the majority of the Brown population live in the deeper areas of the lake. When they have the call to spawn they leave the deep water and head to the shallows of the tailrace. More people catch them during that period of time so it is noticed more than the Bows. Since bows are always there anyway, thier attempted spawn is less noticed.
Additionally, most the bows are fairly young and dont totally simulate to thier envirement away from the hatchery until they have been in the lake for a few years. So, as Phil stated, they have no internal clock.
Most the browns, due to size restrictions and thier instinct to migrate to deeper waters, will have a higher level of maturity. Wich naturally will bring out the "wild trout" in them. I would think that the same would go for bows as well with the "trophy area" slot limits but unfortunately they are "farm dumb" and dont adapt the same.
I cant prove it, but I think all the cross-straining has a bit to do with thier intellectual inept. But that is just my theory.