A little late but wanted to respond with my experience. We had some type of disease hit our pond two years ago. Ironically enough it was right around the time I started to get a management plan together. Typical overcrowded LMB with lots of large BG.
Not sure how many fish died but almost every fish I could see had the same issue (white growth) somewhere on them. Eventually I just didn't spot many fish. It actually turned out to be a good reset for the pond. We started seeing healthy fish again. I put in new cover for the BG and added tilapia in the spring. We're catching bigger and healthier bass than I have seen in a long time.
That said, there are small bass everywhere now. To the point where I have started culling again. If you give it time I would say the lake will repopulate on its own.
I had same issue this fall - white fungus on all the fish I could see with dozens dying - your post is encouraging.
