A. I talked with Dr. Dave Courtemanch, a biologist in Maine, to get answers for your questions; I have had no experience with landlocked salmon. He said that brook trout and landlocked salmon co-exist well because the salmon inhabit the d eepwater regions feeding on smelt, whereas the brook trout are found in the littoral regions feeding on insects. However, brown trout and landlocked salmon do not co-exist; the brown trout outcompete the salmon for food resources. He didn't have any information about how rainbows and salmon get along. He also said that the Maine fisheries people introduced salmon into some lakes having populations of blueback trout (actually a char), and that the salmon introduction resulted in the extinction of the bluebacks.