Mike,
I’m guessing that the 3 inch HBG were lunch for the 8-10 inch LMB and the 20 hand sized HBG haven’t started spawning yet because the water temperature is 54 degrees. I have neither fish but there is a rule to follow that LMB can eat other fish up to 2/3 their body length I believe. Someone can correct me on that if I’m wrong. I’m curious of the size perch (Yellow Perch)? If I understand correctly you hit the 10:1 ratio of HBG (or maybe it’s BG) to LMB on the money. An expert will let you know how to proceed. This is a great site with people willing to help! Good luck!