This is my humble opinion based on many years of fishing lake erie. I believe that the older fish will spawn on or around March 23rd based on water temperature and moon phase. So if you are going to jig fish plan for that date. A crazy trolling bite two days later. The less mature fish will spawn on the next full moon on April 22nd so another great jig bite and two days later a crazy trolling bite. Weather patterns could affect this but I have seen this pattern over and over again over the last 30 years. Just so I am clear the is just my humble opinion and what I would expect.