Y.perch will slow down surface feeding when the water gets 55F dropping to 50F. Below 50F you do not need to feed them. Larger perch like you have often slow down feeding in mid summer especially in your latitude. Many of the YP could be feeding on small FHM if they are abundant. Your main feeding activity of the year will be next spring post spawn when the water is 58-72F. I basically only harvest the 9"-12" YP so each makes a nice sized fillet.
