To beat the fall turnover, move to areas of the lake that haven't turned over yet. Look for off-color, debris-filled water and avoid it. Target clear, shallow bays or creek arms that may still be stable. Cover water with search baits like spinnerbaits to locate active fish. Turnover rarely affects an entire fishery at once, so finding clean water is the most direct path to catching bass.
- Fall turnover doesn't happen lake-wide at once. Shallow bays and creeks often turn over before open water.
- Look for brownish, debris-tinged water to identify turnover zones. Avoid those areas and find clean water.
- Cover water fast with a search bait like a spinnerbait to locate fish during the turnover.
- Below the thermocline, oxygen levels drop sharply. Bass won't hold in unfavorable oxygen zones.
- A cold-night turnover can resolve in two days. A drawn-out event can shut down fishing for a week.
Every year, bass anglers struggle with the fall turnover. As nightly lows drop, the water’s surface layer cools. The colder surface water becomes denser and heavier than the warmer water beneath it, and the lake turns over. When the water columns swap, they stir up sediment and deplete oxygen levels. All of this can shut off the bite, making it hard to catch fish for several days. To help you navigate the turnover, we sat down with MLF Pro and environmental scientist Greg Vinson to learn more about this annual event and how to beat it.
What is the Thermocline and Why Does it Matter?
Understanding the fall turnover starts with the thermocline. This thin layer of water separates the cold water beneath from the warmer water above. “The water gets layered, starting in the spring, and it goes through October,” says Vinson. “You’ve got a warmer, more oxygenated surface layer, and then you have a thermocline. Most importantly, below the thermocline, there’s very little oxygen. That area is not favorable to fish.”
Vinson recalled sampling water on Smith Lake and Lake Martin in his home state of Alabama and found the thermocline to be around 40 feet deep. These are two very clear lakes. The thermocline is much shallower in stained and muddy fisheries, where the sunlight can’t penetrate as far. No matter how deep the thermocline is, algae—and therefore oxygen production—won’t occur deeper than light can penetrate.
What Triggers the Turnover?
Anything from a few cold nights to a tropical system dumping torrential rain can trigger a turnover. Essentially, as soon as surface temps cool and drop below the water beneath, the water turns over.
“There’s a lot of organic matter that gets mixed at that thermocline,” says Vinson. “That’s why when you see a full-tilt turnover, the water will have an odd color to it, and you may see a little debris.” Looking for this brownish tint will help you identify areas of a lake that are turning over. Not every area of a fishery will turn over simultaneously. “Shallow water can turn over quickly,” Vinson explains. “Often, a creek or large bay will turn over before other parts of the fishery.”
If the turnover is due to a couple of super-cold nights, the system can recalibrate in a couple of days. Sometimes, though, the turnover can be drawn out, and it may take a week for things to return to normal. During this time, fishing can be extremely tough. But you can still catch bass.
How to Beat the Fall Turnover
Remember, an entire fishery doesn’t typically turn over all at once. Look for cues, like the off-color water, and if you see them, consider targeting different areas. “If I get in an area and I’m seeing clues like lethargic, unresponsive fish, the first thing I do is change sections of the lake.”
If a large rain caused the turnover, Vinson recommends heading to the back of the creeks. Fish often migrate to moving water because it’s well-oxygenated. The more current you have, the more the water is mixed and the less impact the thermocline can have. Focusing on baitfish is key throughout the fall, but especially when trying to dodge a turnover. Use your graph to locate bait below or look for bait along the surface and focus on these areas.
“Sometimes it’s just as simple as finding the food source because they’re susceptible to all the same things that the bass and every other fish are,” says Vinson. “If you’re seeing a lot of bait, odds are you’re in a good area.” Vinson recommends grabbing a search bait and covering as much water as you can. “This time of year, fish are typically dialed in on baitfish, so keep your presentations in that same range,” he says. “Some of my favorites are spinnerbaits, jerkbaits, and swim jigs in shad patterns. A lot of fish are looking up that time of year, so it’s a good time to throw a bait that runs near the surface.”
You can also use your electronics to help you. Vinson has found that he can actually see the thermocline using his electronics. He can see it on forward-facing sonar, traditional 2D sonar, and down-imaging. “You’ll see a dense layer,” he says. “It’ll look sort of cloudy, but it’ll have a distinct edge.” If you’re not seeing that, but the screen looks busy, there’s a good chance you’ve already gone through a turnover.
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