Knowing a bit about the lake's ecology (or finding out if anyone on the forum knows) might help. If the lake has no deep-water forage fish like cisco, whitefish or smelt -- and perhaps perch are in that category as well, not really sure -- then I think the lake trout will be more likely to make dawn and dusk forays into shallow water outside their preferred temperature range like frozentripper talks about, since that's where there are always minnows to eat.
To add a couple more techniques some people use:
- vertical jigging, either with a setup like swede's or with a spoon and sinkers -- this can only work on those glassy-calm mornings/evenings when your canoe is able to sit in place on the water. The other disadvantage is that you can't cover ground while jigging to find the lakers, so it helps to have a depth map to know exactly where the underwater points/dropoffs are.
- as frozentripper alluded there are stickbaits designed to dive as deep as 18 feet, which is deep enough for lake trout in any season. Trouble is that depth assumes a more consistent trolling speed than a canoe usually affords, and more line out than you'll usually have space for on a trolling run in a backcountry lake. Adding some weight to the line, like a rubbercore sinker a rod length from the lure, might help.
RobW, I'm curious about your bottom bouncer technique... do you actually walk it along the bottom, or just use it as a big sinker to get some depth?