Eastland, that is great news. We'll try to provide you with as much info as possible.
Sunil, you seem to be doing something right. Yellow perch certainly spawn before crappie and so the young perch should eat lots of crappie fry. The problem I have is that even a 10 inch yellow perch can be eaten by our LMB and CC.
The secret seems to be having multiple predator species. That way, if the population of one predator falls, another predator can pick up the slack. We seldom see a crappie under 10 inches in our lake.