Just my opinion, I dont know as much about Blue Cats in a pond environment, but in the rivers the Blue Cats seem to lose eating qualities the older and bigger they get, if it was me I think I would harvest some of the bigger ones and restock with a younger ones.
Blues tend to be pretty aggressive in cleaning out almost anything in a closed space, You must have some pretty good cover for that many GSF to survive, actually I have seen a couple decent sized Blues or Flathead dropped into a pond just to clean it out. it worked great.
