Lakers, as we call them, live in cold water from 40 to 52 degrees Farenheit. Generally they stay on the bottom, but will sometimes be found suspended when the water temp is at their preferred temperature. In the winter, under the ice they will usually be right on the bottom. Also, in the mid-summer, after the water warms up, they will again be on the bottom. But in the spring after the ice goes, until mid-summer when the water warms up past the 50 degree mark they can be found suspended anywhere in the water column.
Lakers feed more in the mid-morning hours, but can be caught all day long by jigging, trolling or casting. Leaded jigs with a piece of artificial or real bait attached, and jigged on the bottom catches lot of lake trout.