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Curious Iowa: How do the state’s fish hatcheries work?
There are five fish hatcheries in Iowa and three of them are concentrated in the northeast corner of the state
Jun. 9, 2025 5:30 am, Updated: Jun. 9, 2025 7:36 am
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Summer is a popular time for fishing trips across Iowa, but how can anglers be sure they’ll catch fish? And how does the state maintain a fish population that allows for fishing? Those questions can be answered by Iowa’s fish hatcheries, which fertilize, rear and stock fish species across the state each year.
What role do fish hatcheries play in Iowa, and how do they work? That’s what one curious Iowan wanted to know. They sent their question to The Gazette’s Curious Iowa, a series that answers readers’ questions about our state and how it works.
What are fish hatcheries?
Iowa has five fish hatcheries run by the Iowa Department of Natural Resources, under the agency’s Fisheries Bureau.
Although all five hatchery facilities are under the umbrella of the DNR, each has a different focuses when it comes to breeding and rearing fish.
For example, the three fish hatcheries that are clustered together in northeast Iowa — the Chuck Gipp Fish Hatchery in Decorah, Big Spring hatchery in Elkader, and the Manchester Fish Hatchery — rear different species of trout to stock in the region.
The Rathbun fish hatchery, in Moravia, is a warm water hatchery that predominately rears catfish and walleye for the state. And the Spirit Lake hatchery, in Spirit Lake, is a walleye, northern pike and muskellunge hatching and rearing station.
All five facilities are responsible for raising fish that are used to stock Iowa’s streams and lakes. In total, they raise about 130 million fish per year across all five hatcheries.
Brian Malaise is a natural resource biologist with the DNR at the Chuck Gipp hatchery in Decorah.
Without the work of fish hatcheries restocking fish throughout the state, Malaise said some fish species would not be prominent in the state.
Using walleye as an example — although his facility does not rear walleye — Malaise said there is very little natural reproduction of walleye in the state.
“There would not be walleye fishing in Iowa if it wasn't for hatcheries and, honestly, for trout too,” Malaise said.
Malaise said there are about 78 streams in Iowa that currently have self-sustaining natural reproduction of trout, but the majority of those are brown trout.
“We have probably 10 streams that have brook trout in it, but there's very little,” he said. “There is basically no natural rainbow trout reproduction.”
He said hatcheries help sustain the population levels of several species of fish so Iowans and out of state visitors can catch fish and partake in the state’s fishing culture.
Malaise said having more fish in Iowa’s lakes, streams and ponds bolsters fishing activities in the state and provides an economic benefit.
Northeast Iowa’s Driftless Area is home to three of the state’s most popular trout fishing destinations. Malaise said the thousands of fishing trips taken to the streams each year, combined with the licensing fees anglers pay to fish, provides several million dollars to the local economy.
Specifically, he said North Bear Creek near Decorah sees about 35,000 fishing trips taken on it per year, while South Bear Creek in Winneshiek County sees about 30,000 trips a year. Each fishing trip is estimated to cost about $46, Malaise said. That equates to about $4 million annually just from those streams.
How do hatcheries work?
Mike Posanski is a DNR fisheries biologist at the Big Spring hatchery in Elkader. He said his facility, first and foremost, grows fish.
Many of the fish grown at the Elkader hatchery are hatched in Manchester, then delivered to Elkader to be reared.
When the fish show up, they are about an inch and a half long and about three months old. Those fish are grown and used for stocking the following year.
The Big Spring Hatchery stocks about 125,000 fish annually, out of the approximately 340,000 fish stocked from the three trout hatcheries in northeast Iowa.
The entire process of raising a fish from egg to a catchable size takes 12 to 18 months, Posanski said.
Currently, Posanski said his hatchery raises only rainbow trout.
It’s “very limited. … All we have in the facility is catchable-sized rainbow trout, which is pretty much exclusively for people to catch,” Posanski said. “That's the point of the program. It's why we're putting them out there.”
Malaise said it costs the Decorah hatchery about $3 to produce one fish.
“It takes us 18 months to go from trout egg to a catchable-sized trout, so it's an expensive product for us to raise, but the return for revenue for anglers (and) for the economies are just crazy,” he said.
Raising fish starts with sorting through trout eggs after they spawn in December January and February, Malaise said
The hatchery staff collect the unfertilized eggs in a net and place them in a pan. Once in the pan, staff place male fish’s sperm — known as “milt” — over the eggs to fertilize them.
Aaron Schwartzhoff, a technician at the Manchester hatchery, said the facility is the only fish egg collection and incubation operation in Iowa.
After fertilization takes place, staff place the eggs in an incubator that has about five gallons of water running through it. After 18 days in the incubator, the fish’s eyes begin to form in the egg, marking the “DE stage.”
The dead or unfertilized eggs are discarded, and the remaining eggs are placed back in the incubator for an additional 22 days to continue developing before they hatch.
“Once they hatch, they still don't look like a fish,” Malaise said. “They have a head and a tail, and they have a yolk sac on their belly.”
Malaise said the fish go into the incubator once more while their yolk sac is absorbed. After that, the Manchester facility staff place the fish into a small tank.
“At that stage, they instinctively want to swim up and feed, so it’s pretty vital that we start putting the dried food in the tank,” Malaise said, adding that the fish food is powder-like and floats on top of the water. “Once you get them trained to feed and they continue to grow, you just keep giving them bigger and bigger sizes of feed.”
Malaise said they feed the fish like this for about 14 months so they can grow larger, into a catchable size before being stocked in Iowa’s waters.
Why are three Iowa hatcheries all in northeast Iowa?
Schwartzhoff said there are several reasons why three of Iowa’s five fish hatcheries are clustered close together in the northeast corner of the state. Part of it is just due to the logistics of trout stocking.
“The trout program in general raises a lot of fish because we are out stocking streams almost every day during the week, with the three trout hatcheries putting hundreds of pounds of fish in every day all these streams for people to catch,” Schwartzhoff said. “So that's why, like the three trout hatcheries are close together, because we need the available space.”
Additionally, Posanski said Iowa’s Driftless Area plays a role in the close proximity of the three hatcheries.
The Driftless Area covers northeast Iowa, southeast Minnesota, southwest Wisconsin and northwest Illinois. During the last ice age, glaciers didn’t cover the Driftless Area. That allowed for deeper valleys, exposed bedrock and geological bluffs.
The region also is characterized by its karst terrain, Posanski said. Karst terrain is made up of lake sandstone and limestone, which leads to cooler water temperatures.
“Those cold-water springs are pretty much the only reason we can have trout in this in the state,” Posanski said. “So, if you look at like where the trout streams are, they're all in that Driftless region in that northeast corner of the state, because that's the only place that has springs that can support those fish.”
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Olivia Cohen covers energy and environment for The Gazette and is a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.
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Comments: olivia.cohen@thegazette.com
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