Fall Structure: What Draws Fall Fish?

By Nick Johnson

Finally, the blistering heat and humidity of this past summer is starting to thin out and cooler weather is on the horizon. Everything seems to be eating and water levels are generally very stable in both rivers and lakes. Fall is a transition time, slow as it may be at first, and an excellent time to catch a multitude of different species. Fall is also a time when the big predators feed heavily as winter looms a few weeks out.

Iowa lakes from the southern border to the north, hill country to the flat plains are fairly diverse depending on what county you are in. All have some type of structure that keys in fall fish no matter how simple. The primary motive for most species this time of year is forage and in later fall, winter staging. As the water cools, species like walleye and pike that often retreat to deeper, cooler water during the hot summer months are offered a reprieve and can be found shallower. Lets take a look at what I consider the Top Four structural components or areas to focus on for early to mid-fall.

The First Break
What I mean by this is the transition from shallow water to deeper water. Depending on the lake this change may be sharp, gradual or barely evident. In deep lakes, I look for this transition space in 10-15 feet of water. In shallower lakes it may only be 3-6 feet where the separation lies. If the water is clearer, this is often the depth where emergent weed growth stops which is an additional bonus for concentrating bait and predators along this structure edge. In late-summer to early-fall, many species relate to this depth gradient as it offers a lot of food and nearby cover. You won’t just find fish everywhere though, look for additions to the break such as weeds, hard bottom, an inside turn or outside point. On the flip side to predators moving shallower as the water cools, certain species like crappie stage along these areas before moving deeper later into the fall season.

When it comes to bass, crankbaits, swim jigs and jig/craw tail combos are an excellent option. Bass will feed on a multitude of prey items this time of year but really love crawfish due to the high protein and fat they gain from them. Crankbaits will cover water and find fish, jigs will put numbers of big fish in the boat. Think big baits for species like walleye, pike and muskie here as well. Big crank baits, swim baits and even big live bait if that’s your calling. The toothy predators are looking for a big easy meal to bulk up for the cold months ahead.

Still Green
As fall progresses, once-green weeds begin to die off. The decomposing plant matter uses oxygen and results in an oxygen sag in the water around them, to some extent. Minnows, small fish and other forage species move to areas where there is still green weed growth that continues to offer food and shelter. This scenario is more prevalent later in the fall but can still be seen before the weather really cools down.

Predator fish are right there with the forage and places like the edges and isolated clumps can be dynamite hunting grounds for species like muskie, pike, perch, big bluegill, bass and the list goes on. Many of you reading this know that fall muskie fishing can be excellent and this is a prime example of what to look for when venturing out. Combine that with rocks or steep breaks and you have a classic fall fishing spot. You may not be able to tell if the weed growth is dead or viable just by looking at a graph but if you snag a bit of it and bring it up you will know right away.

I’ve covered fall walleyes in a previous article but this topic really ties into targeting them late in the season. In early fall and even parts of mid-fall, many walleyes are still deep. When the water temps start to dip into the 50’s a lot of these fish venture into shallower water, especially at night to forage on schools of perch and minnows that are relating to flats with still green weed growth. This is the prime time to slow troll over these flats and weed contours. Muskies will pull up shallow as well during this time and it pays to do some research on peak feeding windows in relation to moon rise and moon set and focus fishing efforts around those windows.

Choke points in a lake tend to be a very overlooked location by-and-large. What I am talking about is a form of bottom or shoreline contour that creates a natural funnel from a bay, a creek arm or one basin to another. A good chunk of Iowa lakes are man-made reservoirs and have finger bays or arms that extend off of the main body, some with creeks that flow into them. Find the point where the bottom contour begins to funnel towards the middle and start looking with electronics. It depends what species you are targeting but areas like these are natural movement routes for batfish, especially shad. Bass, white bass, walleyes, crappie and even catfish will stage in these locations and ambush concentrated forage.

Think Deep
If the water is still warm, many cooler water fish like walleyes, smallmouth and pike will remain on deeper structure like humps, deepwater points and reefs. If targeting walleyes, don’t be afraid to fish deep if the lake allows. I’m talking like 35-50 feet. As the water cools these fish will begin to move shallow and especially in late fall, can be caught in very shallow water in low light. The big smallmouth bass tend to remain deeper and the three key spots I mentioned in 20-30 feet can be really good, most notable if they contain some type of rock or rubble.

Largemouth bass in early fall can also remain deep and it is not uncommon to find schools of them staged in 20-25 feet. The finger bays I mentioned previously are a classic example of that. As shad travel into and out of these bays in the fall the largemouth will set up shop in the natural funnel areas to ambush them.

Fall fishing in lakes can sometimes be challenging but often times very rewarding. If you aren’t finding fish on shallower structure, move deeper and utilize electronics to pinpoint edges, contours and especially bait. Many species tend to be schooled up in key areas so once you discover a pattern, stick with it. Good luck on the water this fall!