I have usually done well as soon as the ice started to melt from the shoreline. In the shallow coves the open water may only be 30 or 40 yards from shore out to the ice but it warms pretty fast. I would float a jig under a bobber in that open water. Most days I would do pretty well and decent size too. But it's fishing, and success varied from day to day. It was just good to wet a line after a long cold winter.