Hi Eyedoc, welcome. The GSF very likely ate a goodly portion of the bass, since by the size of some of the GSF they were already in there when the bass were stocked. If the bass were stocked as fingerlings, probably a good portion of them got munched.
You should stock 8-10" LMB as soon as possible. I would also recommend stocking either northern pike or tiger muskie, about five per acre, 10-12" long each so they don't get eaten. I worked with a pond years ago that was so badly overpopulated with GSF when I first started working with it that that's all you ever caught, and none of them were over 3", most smaller; you could catch one every single cast, from anywhere in the pond. That pond was two acres, like yours. I stocked 40 one-pound LMB that I caught from nearby ponds, and 20 12" northerns that I got from a hatchery. Within three years 4-6 pound LMB were being caught very regularly, and a seven-plus pounder was caught by a friend of mine; a year or so after that someone caught a 36" northern. The LMB began spawning successfully, and the bluegill recovered and took the place of the GSF as the predominant sunfish in the pond. And the pike never decimated any of the other species, not even close.
So all is not lost, but you do need to amp up the number of predators, and pronto.
