From what I understand they like bright, still, and stinky in the winter. I would guess they normally hunt in near darkness in the winter due to snow cover and that is where the warmer water is. Appeal to their behavior and you may get better luck. Also I noticed that in the winter the schools are tighter, so it may take some time for the schools to come across your bait.
That's all I've got, and I am no ice fisherman. Nor do I want to be.
