Muskie. (DNR photo)

The Iowa Natural Resources Commission has approved spending $75,000 on a filter system for the Spirit Lake fish hatchery in Dickinson County to improve the production of muskellunge or muskies.

DNR fisheries supervisor, Jay Rudacille says the system is needed to obtain better water to raise the fish. “The hatchery has been facing two significant challenges in recent years. These challenges are gas supersaturation and zebra mussels,” he says. “Of the three species of fish raised at Spirit Lake Hatchery muskellunge has suffered the most due to these issues.”

He says the gas supersaturation in the water they use from Big Spirit Lake is a natural phenomenon. He says the supersaturation caused up to 60 percent of the one-and-a-half to three-inch fish to die, and 26 percent of the fish had deformities and were removed in 2022.

Jay Rudacille. (screen cap from meeting)

Rudacille says the new system will solve the gas problem and also keep out the potential zebra mussel larva. “The source water for this system will be dechlorinated municipal water — meaning that it will be aquatic invasive species (AIS) free — thereby eliminating the risk of spreading AIS through normal hatchery operations,” he explains.

The hatchery also has northern pike and walleyes, but they will not be grown in this system. “It’s not really going to help the other species unless we can put those fish in the system as well. So we’re having the most trouble with muskies at the current time, and this was a solution that we saw to help with the culture of that of that species,” Rudacille says.

Kim Hawkins from DNR fisheries says the water issue has gotten worse in the last eight years. “From 2014 to present, we’ve had to overproduce fish so that we meet our quotas. And we have not been able to do that in 2020 and 2021,” Hawkins says. Commissioners asked Rudacille about the cost for the system when only 3,000 fish are stocked in Iowa lakes. He says they do trade thousands of muskies that are not stocked for other species of fish.

“For instance, with South Dakota, we will trade them some muskies at a smaller size, and in turn, we will get yellow perch — which we don’t produce in our hatchery system,” he says. “With Missouri we will trade them some muskies at a four-inch size and in return, we get 140,000 channel catfish because we don’t spawn them within our system.” He says Nebraska stopped trading with Iowa because of the potential for zebra mussels.

The new system eliminates that concern and may lead to more fish trades. “And so I’m sure that would be looked upon very favorably by some states that do not want to risk importing zebra mussels to their states,” Rudacille says. Rudacille says the number of fish stocked right now is based on the requests they get and they are only stocked in certain lakes.