Same thing happens when we troll for walleye.When the wind dies ,usually the catch rate goes down too.When we used to perch fish,it seamed when boat was bouncing up and down or swinging right and left the perch were more aggressive with the bite.When the wind died and boat was very still,those perch really bit light.That minnow was still and they had time to nibble off that minnow from the hook.Had alot of stripped perch rigs without feeling a thing.