It was just a few weeks ago when staff with the Fisheries Bureau of the Iowa Department of Natural Resources visited South Pine Creek Wildlife Management Area to monitor the population of brook trout in South Pine Creek.
The news was good - years of work to protect and enhance the South Pine Creek watershed in Winneshiek County has allowed Iowa’s only native trout to be protected, thrive and continue to naturally reproduce in that stream.
Now, DNR Fisheries staff spawn adult brook trout from South Pine Creek, raise them in a hatchery to about 2 inches in size, and reintroduce them into other streams in Iowa with good water quality. The clean, clear cold water has allowed the stocked fish to thrive in several northeastern streams that have also undergone improvements.
The areas that staff like Northeast Fisheries Supervisor Michael Steuck have determined viable to reintroduce brook trout are those that 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 County, 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 water monitoring, floodplain restoration and bank stabilization. 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, improved manure storage and terraces, also helped reduce sediment to those waters, which led to creating better 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,” Steuck said. “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.
Native South Pine brook trout were reintroduced over four years ago into the headwaters of the Yellow River and Silver Creek because of improving water quality in those streams, and the brook trout have successfully survived and grown in those waters.
“Because of less sediment and better habitat, streams have trout that are reproducing on their own,” Steuck said.