The Missouri River reservoirs in South Dakota are a favorite of anglers from across the region throughout the spring months. The presence of open water, year-round walleye season, and excellent fishing attracts anglers looking to put their first limits of the season in the boat. The spring bite leads to a spectacular early-summer bite across all of the reservoirs, but as the 4th of July comes and goes, fishing begins to slip the minds of many anglers.
Indeed, the summertime blues can hit some of the best fisheries, and best anglers, across the region. This is for a variety of reasons; warm water temperatures can push walleyes deeper into cooler water, peak production of the system means there is an abundance of forage options, this forage the walleyes are keying on is seeking deeper, cooler water as well, and recreational users can produce a significant amount of boat traffic.
Fortunately, there are still fish to be caught, particularly for anglers who can understand deep water patterns. The nature of reservoir fishing sets up a predictable deep water pattern, as the lower third of reservoirs often exhibit features of a lake and offer a variety of deep water structure that can hold walleyes in relatively predictable locations. These areas can then be targeted with a handful of techniques.
Finding Deep Water Structure
The specific type of deep water structure anglers are looking to target when searching for mid-summer walleyes can vary based on the specific reservoir they are fishing, but a few general rules apply. The first is that this is often on the lower third of the reservoir, where current is decreased and the deepest water is present. The second is that structure is from prior to when the reservoirs were dammed, most of which is trees and other woody vegetation. The third is that the shoreline gives a good indicator where some of this deep structure can be, as the lake bottom will often resemble that what is present on the landscape above it.
The specific depths to focus on is the first example of what can vary reservoir to reservoir. For example, the depths found in Lake Oahe will be the most significant, as Oahe is the largest and deepest reservoir of the Missouri River reservoirs. While 30 feet may be relatively shallow on Lake Oahe, it is a good example of deep water structure present on the smaller Lake Sharpe. Anglers should avoid looking to focus on a specific number, but more so areas where appropriate structure is present.
This structure is predominantly going to be submerged trees. Anglers would be surprised by both the amount and density of submerged trees present in the reservoirs. In many cases, these trees may be in 50-90 feet of water, topping out at 20-30 feet down. Indeed, trees greater than 30 to 40 feet tall are still standing at the bottom of the reservoir.
Trees are not the only deep water structure present though. Rock piles, submerged islands, deep points, and particularly subpoints are all common deep water structure. Combining the appropriate piece of structure, with the appropriate depth, is the easiest way for anglers to locate fish. For example, a set of trees on Lake Oahe near Pierre that are in 110 feet of water and top out at 80 feet are not viable locations to fish; however, a set of trees on Lake Francis Case near Platte that are in 50-70 feet and top out at 20-40 feet are much more enticing.
The structure doesn’t necessarily have to be something that shows up on sonar, but also what shows up on a map or on the shoreline. Many times, some of the best locations to target mid-summer walleyes are the sub points that show up off of the main points that were targeted earlier in the summer. Walleyes may just slide out off these points and hold tight on these specific areas, where they can find both cooler water and forage.
Targeting Mid-Summer Walleye
Once deep water structure is identified, it’s time to focus on targeting these areas and putting fish in the boat. Three primary techniques begin to present themselves; trolling crankbaits, jigging vertically, and trolling live bait rigs are the top options for deep, summer walleyes.
One of the staples for summer walleyes is trolling crankbaits on both lead core line or snap weights. The most common way to present these crankbaits is lead core line, but the deep nature of mid-summer fishing can make snap weights appealing for anglers. This is an angler’s preference, but the goal remains the same. Ultimately, anglers want to target a variety of depths, as mid-summer walleyes are often suspended over this deep water.
Trolling crankbaits are often best over large patches of submerged trees, but can be effective anywhere over deep water when fish are suspended. Savvy anglers will trust their electronics to let them know where fish are suspending, as mid-summer walleyes are rarely on bottom. Many times, the higher the fish are, both the more likely they are to bite and larger they are.
Advancements in electronics have also set up for another method of fishing, that is taking the industry by storm, and this is vertically jigging glide baits, blade baits, or even plain jigs and plastics. Front-facing, or live imaging, sonar has taken the guesswork out of this technique and made it incredibly effective for anglers. This method works particularly well for targeting specific pieces of structure and/or specific fish.
The third technique is similar to trolling crankbaits, but at a toned-back pace. This technique would be pulling live bait, specifically crawler harnesses with large blades, suspended behind bottom bouncers or snap weights. This rig can be modified to other presentations as well, such as slowly pulling slow death rigs tipped with a Mack’s Lure Smile Blade or a plain nightcrawler. Once again, targeting suspended fish is key for success.
Deep Water Considerations
When targeting mid-summer walleyes, anglers need to be aware of concerns of barotrauma in fish. Anytime you are fishing depths greater than 30 feet, fish are susceptible to mortality because of barotrauma. When a fish is brought up from deep water quickly, it can result in severe internal damage leading to death. Fish may still swim off, but there is a high likelihood they will experience delayed mortality following this condition.
It is every angler’s responsibility to ensure they are being ethical when targeting fish over deep water. Regardless of steps taken by anglers, fish caught from water deeper than 30 feet will likely experience mortality. When legal, it is a good idea to keep these fish for consumption, or look for fish in less than 30 feet of water when possible.
Mid-summer on the Missouri River reservoirs mean it’s time to focus on deep water. Anglers who are able to identify deep water structure and present their baits effectively can still enjoy excellent fishing throughout the summer months. As always when fishing deep water, anglers are reminded to be ethical and keep fish for consumption to minimize mortality caused by deep water fishing. The weather may be hot, but that doesn’t mean the bite can’t be too! Good fishing!
Learn More About Mid-Summer Walleye Fishing
Mid-Summer Walleyes on Lake Oahe
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Multispecies Madness on Lake Francis Case
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