The largest waterbody in South Dakota, Lake Oahe, often finds itself in the spotlight. The expansive reservoir, which stretches from Bismarck, North Dakota to Pierre, South Dakota, is one of the most dynamic fisheries in the country. While this “boom and bust” fishery has gone through many cycles, anglers should be hopeful 2025 is a year that features ample “boom!”
The massive waterbody is broken down into two distinct areas, Upper and Lower Oahe. The divide is the Highway 212 bridge near Whitlock, which is where both the physical and biological characteristics of the reservoir vary.
Upper Oahe is characterized as shallower, warmer, more turbid, and features large tributaries such as the Grand and Moreau Rivers. Traditionally, Upper Oahe generally has more numbers of fish, although at generally smaller sizes. While not entirely comparable to the walleye factory that is Lake Sharpe, the historic trends are strong numbers of “eater” caliber fish, with a few trophies still present too.
Lower Oahe is deeper, colder, clearer, and includes more hard substrate and main-lake structure. Traditionally, Lower Oahe generally has fewer numbers of fish, but fish that grow to significantly larger sizes. This end of the reservoir features an even greater “boom or bust” element of the walleye fishery.
The composition of fish species varies between Upper and Lower Oahe as well. Throughout the 2024 sampling on Lower Oahe, approximately 35% of fish sampled were walleye, 20% were smallmouth bass, and 30% were catfish, along with a number of other species at smaller percentages. On Upper Oahe, 23% of fish sampled were walleye, 5% were smallmouth bass, and 48% were catfish. Notably, Upper Oahe also saw a higher perch number with 5% of catch being yellow perch.
Factoring all of the above, we’re going to break down both the Lower End and Upper End individually as they function as separate units within the Lake Oahe fishery as a whole.
Lower Lake Oahe
The recent years on Lower Oahe have seen a changing trend compared to prior history, which is increasing walleye abundance on the lower end of the reservoir. In fact, 2024 saw the highest walleye abundance since 2017. Notably, there are numerous fish between 15-20 inches, with a bump up in greater than 20 inch fish as well.
“The 2024 season on Lower Oahe was really spectacular,” said Nick Harrington, Owner of Lip Ripper Fishing. “We had some of the best fishing I’ve seen in my time here in Pierre, and most notably was the quality of the fish we were catching.”
The most positive statistic is the size of age-3 fish. This is an important number when it comes to the health of a walleye fishery, and a target of 15 inches at age 3 is ideal. On Lower Oahe, growth rates are above this target. In 2023, age-3 fish were 15 ½ inches. In 2024, this number rose even higher, with age-3 fish reaching 16 ¼ inches in size.
This is an indicator of an extremely healthy fishery, and means that fish are continuing to work their way through the ranks and reaching desirable sizes. This also means fish do not stockpile at a size, which further improves growth rates as fish continue to age and more fish enter the system.
“The fish I saw on Lake Oahe in 2024 are some of the healthiest, most impressive walleyes I’ve ever personally caught,” states Harrington. “They’re thick, they fight hard, they’re just overall a walleye you can tell is in amazing shape.”
The 2024 sampling results show a significant number of fish between 18-20 inches, including more fish coming up the ranks. These growth rates indicate these fish should soon be exceeding 15 inches as well, adding to the high proportion of fish over the 15 inch mark.
“One thing that really stood out to me this year was the number of 18-19 inch fish, it seemed every time you felt like you had an over and it’d coming in just below 20 inches,” recalls Harrington. “That is what impresses me the most, you’ve got a 19 inch fish going around 3 pounds consistently, that’s pretty cool.”
Upper Oahe
The story on Upper Oahe is a bit different than Lower Oahe. Known for historically good numbers of fish, recent years had seen difficult fishing on the upper end of the system. Fortunately, things began to turn around in 2023 and continue to do so in 2024.
“I’ll be honest, when we fished National Team Championship out of Mobridge in 2022 that was some of the most difficult fishing I’d ever personally experienced,” admits Harrington. “The stocking efforts GFP has done have really been helping flip the script in recent years.”
While overall walleye abundance on Upper Oahe is down from 2023, the 2024 sampling efforts indicate 50% higher abundance than 2017-2022. Throughout these last two years there have been improved numbers of 15-20 inch fish, with short fish behind them.
Growth rates for age-3 walleye are not nearly as strong as on Lower Oahe, but this is slowly improving. Poor growth rates in 2022 were indicated by 12 ½ inch age-3 fish, before increasing to 13 ¾ inches in 2023. This improving trend remained in 2024, with age-3 fish growing to 14 ½ inches.
While this is not quite to the ideal 15 inch mark fisheries biologists look for across the state, it is on the right trajectory. These growth rates are important to note, as the fish in Lower Oahe do grow to nearly 2 inches larger compared to Upper Oahe fish by age-3.
“It’s just so interesting to me how say 60 miles can make such a difference,” says Harrington. “Lake Oahe is, on paper, one reservoir, but honestly it is its own unique fishery just depending on what launch you go out of.”
Fortunately, approximately 50% of walleyes on Upper Oahe are exceeding 15 inches, display a healthy range of size, and are showing improved growth rates as a whole. While times were tough in 2022, recent years continue to show improvement.
“We also need to realize that there’s many factors at play here, Upper Oahe was responsible for both state record fish in fall of 2023, you can still go have an incredible day anywhere on this system,” reminds Harrington. “We say slower growth on Upper Oahe, and yes that’s true, and in the same breath in November you might catch a 26 incher that goes 8 pounds. It’s the nature of the fishery and what makes it so special.”
2025 Stocking Plan
A critical component of the recovery from the 2011 flood, as well as 2019 high water event, has been stocking. South Dakota Game, Fish and Parks (GFP) has stocked Lake Oahe every year since 2017, except for the 2020 pandemic year. These stockings had been focused on the lower end due to the historical difficulties of fish abundance and recruitment.
In 2023, these stockings transitioned to the upper end of the reservoir. The 2024 stockings were then again focused on the lower end, with 2.9 million fingerlings stocked. Traditionally, GFP has wanted to alternate stocking schedules to avoid stockpiling fish on a certain end of the reservoir and negatively impact growth rates.
“While theoretically it might make sense to constantly throw fish into a waterbody, you can certainly have too much of a good thing,” states Harrington. “The different functioning zones of the reservoir I think makes the alternating stocking schedule both effective for the individual area, and the health of the fishery as a whole.”
In addition to the walleye stockings, these stockings have been followed up by gizzard shad stockings. The concept behind this is ensuring there is ample forage for these predators that have been stocked. The 2024 shad stockings saw a record with 2,200 adult shad stocked into the system to spawn. These shad were split throughout the reservoir, ensuring ample food for fish on both Upper and Lower Oahe.
“When we talk about Lake Sharpe we talk about how shad grow fish fast, but kind of stall them out around that 20 inch mark,” explains Harrington. “Well on Lake Oahe, if you can quickly grow a fish to that 20 inch mark on shad then get it converted to smelt and ciscoe, you’ve got the makings of a trophy fishery. That’s what we’re seeing.”
The 2025 stocking plan is a requested 3.2 million fingerlings to be stocked on Upper Oahe, with continued shad stockings throughout the reservoir. While the exact number of fish stocked will vary based on walleye spawning success and gizzard shad collection, this is the target for the 2025 season on Lake Oahe.
Forage Base Update
The growth rates of these walleyes are directly influenced by the forage base within the reservoir. Lake Oahe is historically a rainbow smelt based fishery, but the flood of 2011 resulted in a drastic decrease in the smelt population as fish were literally flushed through the dam. This resulted in the ciscoe population booming.
“Ciscoe and smelt have an inverse relationship,” elaborates Harrington. “When the smelt population is booming, ciscoe numbers will be very low. When smelt numbers are down, the ciscoe population will increase.”
The reason for this inverse relationship is that ciscoe spawn in the fall, and their eggs hatch in the early spring. This ties directly to when rainbow smelt will be moving into the shallows for their spawn, which makes these newly hatched ciscoe an easy food source for smelt.
“Ciscoe were a critical component of the post-flood recovery as the smaller, younger ciscoes provided a forage base for smaller walleyes while the larger ciscoe fed the trophy caliber fish,” details Harrington. “The 10-14 inch ciscoes in the system were a major driving force for the trophy caliber, teener walleyes we saw throughout recent years.”
Cold water prey fish numbers, ciscoe and smelt, are determined by a hydroacoustic survey done by GFP in July and August. This technology allows biologists to literally drive through the water column, while the hydroacoustics determine the size and density of prey fish within the system. This system collects information on water covered, size and number of fish encountered, and coupled with sampling to determine species and target size allows biologists to quantify the number and type of prey fish in the system.
Recent survey results indicate that ciscoe numbers have been dropping in the system since 2022, this is because the smelt population is rebounding. There is a high number of smelt in the system currently, and ideal spawning conditions this spring could result in a population explosion.
“As always, Mother Nature is going to have to be on our side here,” says Harrington. “That said, we’ve got the recipe for a truly special stretch of fishing on Lake Oahe. We’re already seeing it.”
All Signs Point Toward Excellent Fishing
The combination of abundant walleyes, increasing forage, and consistent stockings all point towards anglers experiencing a fantastic 2025 season on Lake Oahe.
“When you look at Lake Oahe, you’ve got good numbers of walleyes, a forage base ready to explode, and overall, an extremely healthy fishery,” states Harrington. “Lake Oahe is a boom-and-bust fishery, and all signs are pointing toward one of the best booms in decades.”
Fishing pressure on Lake Oahe throughout 2024 was right around average, with a slight increase May-July. Anglers that hit the water experienced good fishing, and 2025 has the promise to be even better.
“I’m extremely excited for 2025, while it’s tough to top two state records in the span of weeks like we saw the fall of 2023, I think overall the fishing should be even better,” concluded Harrington. “Whether you’ve never been on Lake Oahe, or it’s your favorite fishery, I believe 2025 is a year you won’t want to miss!”
Lake Sharpe Status and Outlook
Sitting below Lake Oahe is Lake Sharpe, an action fishery that can produce excellent numbers of walleyes of the “eater” class variety. Similar to Lower Oahe, walleye abundance is at its second highest since 2017. Learn more about this action fishery in our Lake Sharpe Status and Outlook!
Mobridge to Host Masters Walleye Circuit May 30-31
Lake Oahe will once again play host to the Masters Walleye Circuit (MWC) as the fourth stop of the tour will be in Mobridge. This early summer event has traditionally produced some fantastic weights, and the status and outlook for Lake Oahe has anglers optimistic this tournament should be just as exciting!
