Lived right up the road for years. Early spring, opening day time period was a good time for large fish when I lived there, but you have to target them. The forage base has changed somewhat, but the migration patterns have likely remained similar. Almost every larger fish that I caught during the first several weeks of the season was taken with cranks fished over deep water. On the east bank of the upper bay, there is a point that sticks out, and has deep water off of it, there is also pretty deep water going south from there. For whatever reason, I had my best luck in the 30-35' range or so, targeting fish suspended around 18-20', keeping my cranks a foot or so above them. Different spring weather could alter that pattern, and it did not last all spring. Husky Jerks, Thundersticks, reef runners all had their days. Alewives were around then, I have heard they are a little scarce now.
Not unusual to mark fish right on the bottom, never had much luck getting them to bite. May have been carp or catfish, not sure. On the east bank, be careful of going from 20' to 3' real quick. This pattern, like any, could have changed. Could work during off peak hours as well. Good Luck, living in Florida now, still miss the UP.