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Iowa’s native brook trout thrive in northeast Iowa streams thanks to restoration efforts

  • 12/13/2022 12:32:00 PM
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Years of work to protect and enhance the South Pine Creek watershed in Winneshiek County has allowed Iowa’s only native trout to thrive and continue to naturally reproduce in that stream.

In 1994, a genetically-distinct strain of healthy brook trout was found in South Pine Creek, a tiny string of water buried between lush vegetation. These brook trout have likely called this place home since before the first European settlers came to the region. 

DNR fisheries staff take special care when spawning South Pine brook trout. Instead of spawning the fish in the hatchery, like they do with domesticated strains of rainbow trout, technicians go on site and spawn the fish on the river bank and bring the eggs back to the hatchery. 

“The eggs are hatched and raised to about 2 inches in size, and reintroduced into other streams to protect this unique Iowa ancestry of brook trout from a catastrophic loss if it was to occur on South Pine Creek,” said Michael Siepker, fisheries biologist with the Iowa DNR’s Chuck Gipp Decorah Fish Hatchery.

Siepker estimates that there are about 500 miles of coldwater streams in northeast Iowa. Not every mile is suitable for brook trout, but there are many miles where brook trout can be stocked. “Iowans deserve to have these beautiful native brook trout in any place that we can have them,” Siepker said.

The ability to sustain trout indicates great stream improvement, as they’re an indicator species of northeast Iowa’s streams, demanding the coldest and cleanest waters to prosper. DNR staff consider water temperature, water monitoring results, current fish populations and streambank erosion data before stocking trout in a stream. 

 “Our capacity to restore brook trout is fairly limited to the number of eggs we can collect from South Pine,” explains Siepker. “We have about 12,000 fingerlings a year that we can use for restoration stockings in about ten sites. “

Brook trout are stocked into a new stream with suitable habitat three consecutive years to try to establish a strong and healthy population. About three years after the last  stocking, fisheries staff sample the stream to see if there are young brook trout in the stream.

The process to determine where this colorful trout that is part of Iowa’s history is stocked is a complex process that involves a lot of partners. “The areas that are determined viable to reintroduce brook trout have undergone significant conservation work to reduce bacteria and sediment,'' said Steve Hopkins with the DNR’s Water Quality Bureau. In some streams, it’s been decades since trout have been able to naturally reproduce and survive. 

Before work began on watersheds such as the Yellow River Headwaters and Silver Creek in Winneshiek and Howard counties, excess bacteria and sediment runoff primarily from farmlands, unstable streambanks, and pastures contributed to elevated temperatures and pollution in streams, creating an unsuitable habitat for trout. 

Grants from Section 319 of the Clean Water Act have funded land improvement efforts on these watersheds, such as stabilizing streambanks, restoring floodplains, and soil conservation and soil health practices.  The DNR has also worked with landowners to reduce the amount of livestock manure that could run into streams and cause the growth of algae and bacteria. 

Although the watershed project goals were to reduce bacteria, sediment reduction most benefited the trout.  The best management practices, such as cover crops and improved manure storage, and terraces, also helped reduce sediment to those waters, which improved habitat for trout.

Trout lay their eggs in gravel so clear conditions are critical - sediment can smother the eggs and prevent new trout from hatching. 

“When you have improved water quality and habitat you have more robust trout populations,” said Mike Steuck, Northeast Iowa fisheries supervisor. “They can successfully reproduce on their own and we don’t have to stock them. We can put our resources into more habitat or stocking other streams that are of lesser quality.”

Healthier streams have been able to support larger and naturally reproducing populations of trout.  As work in watersheds to reduce sediment delivery to the streams continues and expands, there is a new goal: To restore native South Pine Brook Trout populations in those clear, cold streams.

“Because of less sediment and better habitat, streams have trout that are reproducing on their own,” Steuck said.

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