Mitchell anglers find thrill in chasing elusive flathead catfish in SD's only man-made lake they inhabit

May 15—MITCHELL — Lake Mitchell is widely known for its long history of algae woes, but it's considered a rare gem with a healthy population of flathead catfish to a small group of local anglers.

Ryan Rumbolz has spent much of his life fishing for flathead catfish out of Lake Mitchell and Firesteel Creek. The thrill of catching the elusive fish that can weigh as much as 30 to 40 pounds is something Rumbolz described as an "unreal rush."

"They are the king of the water and are very tough to catch. When one hits your line, it feels like a snag on something huge. The biggest one I've ever caught out of Lake Mitchell was 42 pounds," Rumbolz said. "There aren't any fish like it in the lake or any lake in the state."

The process of flathead catfishing is as unique as the fish itself. Unlike most popular fish in South Dakota bodies of water, flatheads are far more active at night. To have a chance of landing a flathead, Rumbolz said a long night is in order.

The apex predators dominate the waters they inhabit and tactfully ambush its prey. When targeting large flatheads in the 20- to 40-pound range, the bait Rumbolz uses are live 6- to 10-inch bullheads.

"You might pull an all-nighter and not catch one flathead because they are rare and hard to find. They sit below trees and don't move much during the day, but they start cruising at night looking for any decent fish they can find," Rumbolz said of a flathead's feeding patterns. "Some years, I'll fish 40 times a year and catch only one that's gigantic. They are such a rare fish, especially around this area."

Lake Mitchell is the only man-made body of water in South Dakota that's not a Missouri River reservoir lake with a healthy population of flathead catfish.

It remains a mystery as to how flathead catfish populated Lake Mitchell. Rumbolz said there are rumors of people illegally dumping the fish into the lake nearly a century ago when it was built in 1928 — a theory he strongly doubts.

David Lucchesi, a South Dakota Game, Fish and Parks fisheries biologist, speculated the species could have been introduced to the lake when the city had to pump water from the James River into Lake Mitchell several decades ago. At that time, the city's lone source of water was supplied by the lake and a drought had depleted the water. The drop in water levels prompted the city to pump James River water into the lake upon being approved to do so.

"We don't know how they got in there. They pumped water out of the James River back in the day, and I've heard some say that coincides with the time that flatheads were established," Lucchesi said.

Prior to being introduced to Lake Mitchell on an unknown date, the only nearby waters with healthy flathead catfish populations were the James River and Missouri River.

The rare opportunity Lake Mitchell offers has created a small local culture of flathead catfish enthusiasts. With the growing popularity of flathead catfishing, Jaryd Guericke, a Mitchell angler, saw an chance to host a catfish tournament on Lake Mitchell.

The 2022 event showcased the abundance of flatheads inhabiting Lake Mitchell, as the winning team reeled in a 53-pound bag of catfish. A 25-pound flathead was the biggest fish of the tournament.

With the city's plan to dredge Lake Mitchell in hopes of reducing the algae woes hampering the body of water, Rumbolz fears flathead catfishing in Lake Mitchell could be in jeopardy if the project moves forward. On June 4, voters will decide whether the city can utilize a $16.8 million loan to fund the proposed mechanical dredging project.

As debate around the lake dredging project has raged on, groups in support and opposition have arised. Rumbolz is among the residents opposed to the project, largely due to his concerns of the impact it could have on fishing.

"It would all come to an end," Rumbolz said of Lake Mitchell's flathead catfishing opportunities. "I've caught big flatheads that are 20 years old. They take a while to get as big as they are in the lake now, and it would be terrible to see these rare fish go."

If the project advances, a significant drawdown of the lake would be required for crews to use equipment to remove phosphorus-laden sediment along the lake bottom. A drawdown of the lake would result in a significant fish kill, according to the engineer who led the design of the project. However, the natural channel of the lake will not be drained and will allow for some fish survival.

According to Lucchesi, flathead catfish could manage to survive a significant drawdown of the lake. Another popular spot local anglers catch flatheads is in the Firesteel Creek, which feeds water to Lake Mitchell.

Lucchesi said the fish's ability to migrate upstream into the creek will also help the species survive during a drawdown of the lake.

"We may lose some of the flathead population, but you're going to have some of the flatheads moving up into Firesteel Creek and doing just fine," he said.

Considering there are flatheads inhabiting Firesteel Creek, Lucchesi said the species could survive in the creek during a dredging project.

If the dredging project moves forward, a large portion of the lake's natural channel that runs through the center of the body of water will not be drained. While project engineers confirmed there will be a large fish kill as a result of the drawdown, Lucchesi said some fish could survive in the channel.

"There could be some survival of fish depending on how far they draw it down. And some flatheads may survive and rebuild. When you draw down a lake, you expose the sediments and airify it all. When you fill it back up, we see a boost in productivity that fish respond well to," Lucchesi said.

GF&P officials have confirmed the agency will restock Lake Mitchell with fish following a dredging project. Flathead catfish are not among the species listed to be restocked.