You know where the spawning beds are?
I would look for changes in the weed beds, especially the edges starting at those beds and concentrating whenever I found a channel either with current or simply paths through the weeds. Work the outside weedline as close to the spawning areas as you can find it, looking for weed fingers and changes in contour. Buried or standing wood is another thing to look for, or changes in bottom composition and those very often go with changes in the weed pattern, such as patches of sand or rocks. Any stream or creek flowing in or out is another clue; find the channel if you can. If you have a hard bottom point with standing rushes coming out of the water, never overlook that, or if there are arms to the body of water check for holes around the throat. By holes and breaks in this kind of body you may be talking about as little as a foot or less difference in bottom structure. You can also clue on the water birds; they will be working areas with the same forage as game fish will be after; so watch where they fish. Any such signals on the wind swept shoreline should have piled up forage if the body is big enough to build up much wave action. Where white caps break on heavy weed beds can be very good spots to find fish feeding on both wind pushed bait and that carried back out through the base of the weed bed by the undertow. They can feed both directions from stations on that outside weedline.
That is open water. You can get an initial idea by taking an easy cruise around before wetting a line.
Carry your open water results onto the ice. There will be no deep basin there; so you may not find as much seasonal movement as in those cases where there is one. Comfort zones will be pretty uniform over the whole thing; so you can concentrate more on feeding and breeding areas. When climate changes the conditions it tends more in these kinds of waters to change the whole thing.
Any one of those things might be your tip off. Differences may be obvious but usually will not be depending on how big the body of water is among other things. One of the best things to find is unmarked or unmapped structure. If you know the fish are there, they are using some sort of guideposts to move around by. those may change with the seasons such as weedbeds, but if you can find perhaps a bit deeper hole adjacent to both spawning and forage areas, you should be able to do well.
One thing about shallow bodies, you can cover the whole depth with very small presentations, which should show you where some fish are; then it becomes a matter of finding better sizes and numbers from that starting point. You may not have to increase bait size either to get into better fish. Troll your peanut cranks rather than the bigger lures and this time of year watch for developing holes and channels in the declining weedbeds.
For panfish, especially bluegills go down to light lines and waxie sized offerings. Float and fly over the tops of green weeds. For crappies move up a little to little plastics like the small tubes and paddletails. Sometimes it pays to get started by slow drifting an outside weedline with a nightcrawler or a garden worm or even a waxie or two hanging straight down over the side on a small hook with little more than a split shot for weight. CT is quite right that it may very well take live bait to get your orientation started. The walleyes are very likely weed oriented rather than open water as one might expect in deeper lakes, and may also take the smaller baits.
It also pays to fish a quiet boat. Nothing is ever very far from you, it is always relatively exposed and therefore very often more easily startled and sound travels extremely well underwater.
There really is no single secret to this kind of lake. It is a matter of putting together clues.
All that being said there is another approach that sometimes works and that is to kick up your trolling speed with shallow running cranks on longer lines. One other thing, if there are pike one tactic that often works is dropping a flashy spoon in the prop wash behind the kicker at the higher trolling speeds. My grandfather took a lot of pike with his big old gold KB spoon flashing just about where the prop wash started to flatten out. A shallow lake may not have many, if any, larger pike, but the hammerhandles may get up to 4 or 5 pounds and can be a lot of fun.
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dutch
I fish therefore I am (I guess)
if I fish not... then what?