There is bound to be more and bigger fish some days than others, considering they stock different numbers each day... And sizes vary by season. That could explain this.
I just don't see how a daily stocked fishery can really be "declining" for any reason except for less fished stocked. It's just a pretty hard sell for me. Of course if they stock 10% less fish each day, it will appear as if the fishery is declining, but that is a hatchery problem, not really a problem with the fishery itself, if you ask me.
Frankly, I fish 95% catch and release in the red, blue, and white ribbon areas, but I will be honest with you, when I go to a trout park, I come back with a stringer of fish. I don't think there is a thing wrong with it either. I mostly fish with bait, catch four, keep them all, and spend a nice, relaxing day at camp, or maybe go squirrel hunting, or fish for smallies on a nearby stream. It's all just part of the trout park experience for me, and I like it. If other people want to fish with flies, and catch and release, that's fine (there's even a catch and release area just for folks like you). I don't see why people have a problem with the way I choose to fish, and want to make 2/3 of the trout park catch and release only.