Your forage fish are not getting enough to eat as it currently is. Our forage fish need more to eat. The easiest way to this is to feed pellets but you have too many forage fish currently. Your LMB would eventually become stunted too. Your pond is completely out of balance.
I think all those statements are true. But the LMB will become stunted in everybody's ponds if they weren't kept under control by the top-of-the-line pond predator; man.
I think that if he fed the BG, added LMB, and kept an eye on things, the pond would slowly get back into balance, then if some LMB were not removed, then it would become LMB heavy/BG light, and stunt. But, that's without any intervention from man.
One thing that hasn't been asked or answered is where did the LMB or other predators go, IF there were any in there in the first place?