Depending on the species you target, you might fish in many different depths through the winter, but I’ve found that day in and day out I catch my biggest fish on the shallowest end of the spectrum. I’m not saying you need to go the lake and drill a hole in two feet of water and start fishing, but typically shallow fish will be more aggressive and the biggest fish will live there as well.
Why shallow? Shallow water has a lot more life, in general—more oxygen, more structure, more cover, more light. This means more food and more fish. I am not sure why anglers have a hard time building confidence or trust in shallow water, but once you become a believer it is hard to go back. If I look back at all my winter trophy fish including pike, walleye, bass, trout, and lake trout, all my biggest fish came in shallower-than-average depths.
When I approach any fishing location I focus on two things: finding food and the interaction of where and when the fish are feeding on that food. Once you figure out that detail you are in the ideal location. And once you know the areas that the fish are looking for, you can then seek out the shallowest part of that area.
For example, if you have walleyes feeding on shallow humps, with deeper water around them, they are using the hump as an ambush point to where the shad get pushed up the hump wall right to them. This is a standard feeding procedure for walleye.
Now take that same theory and apply it to a shallower situation. If the typical hump or piece of structure in your lake is 12 feet deep, try and find a hump that tops out at six feet down. You won’t catch as many fish but the quality of your catch will be much greater.
Give it a try this winter!