Read up on how to do a relative weight study on the bass which can indicate if you have too many - or at least not enough for them to eat:
https://appliedecology.cals.ncsu.edu/wp-content/uploads/ANR-1193.pdfMy guess is a horde of small bass are eating the young-of-year fish. But take out too many bass and you might have a horde of small crappie to contend with.
Still, taking out 50 small bass per acre on a 20 acre lake is 1,000 fish which would be a chore. Start now and keep records on the relative weights over the summer - which should start increasing.