Don’t quote me on this, but I belive the St. Louis River doesn’t open until the 15th. I think it’s off limits until the MN opener. As far as where do the fish go? Hopefully someone with more intimate knowledge will chime in, however, i do believe some stay in the River, and for others, Lake Superior is home. The Wisconsin waters of Lake Superior are open to fishing all year. So right now might be a good time to be trolling cranks along the the South Shore. Look for a good mud line and work the edge with a variety of cranks on planer boards or even dead sticking straight out the back of the boat. Never know what you are gonna catch. Lakers, browns, coho, walleye… But if you are planning on sticking to the river, lots of people pull crawlers on spinners, some prefer jigs & minnows, while others stick to plastics. It can be a mad house on the MN opener, kinda like playin bumper boats.
Hope this helps.
Welcome to IDO!
Erik Osberg