Without a serious fisheries survey, it is only speculation but what I often see is the originally stocked fish do quite well, giving you those 10+ pound bass. Then after that the bass do too well spawning, you get too many bass and all subsequent generations are over populated and stunted and you end up with piles of 1-2 pound fish with that occasional rare trophy...

Thin out those little guys and work on bringing back mid size range forage.