Wild trout of Northeast Iowa

by Bill Kalishek, Iowa DNR Fisheries Biologist, Decorah

Northeast Iowa is blessed with trout streams. These are the small spring fed streams that have water temperatures cold enough to keep trout alive in the summer months. The water temperature coming out of these springs is generally at 50 degrees. And even after this water flows through miles of stream the water temperature rarely gets above 75 degrees.
Historically brook trout were the only trout species native to these cold spring-fed streams. But as settlement increased and land use changed, the natural spawning of brook trout began to decline. Stocking of brown and rainbow trout started in the late 1800s to replace the already dwindling brook trout numbers.
Eventually, most of the 105 coldwater trout streams in Iowa were totally dependent on the stocking of hatchery trout to maintain populations. As late as the 1980s wild, naturally reproducing trout were relegated to just six streams in Iowa. Five of these streams had wild brown trout populations and one had a wild brook trout population.
Fast-forward this picture to the year 2005. There are now 26 trout streams that have brown trout populations completely maintained through natural reproduction. Plus, another three streams that support natural populations of brook trout.
The stream with the longest history of wild brook trout populations is south Pine Creek in northeastern Winneshiek County. Offspring from these brook trout were used to establish additional populations in the upper two branches of French Creek in Allamakee County in the 1990s. Stockings of these wild brook trout from South Pine Creek continue today at various locations such as Little Paint Creek in Allamakee County and Duttons Cave Spring in Fayette County.
Brown trout are becoming widespread. The largest populations are in North Bear Creek in Winneshiek County and Waterloo Creek and French Creek in Allamakee County. But several other streams have good fishable wild brown trout populations: Coldwater Creek and Trout River in Winneshiek County; Clear Creek, Paint Creek, and Little Paint Creek in Allamakee County; and Ensign and Brownfield Creek in Clayton County.
This increase in the number of streams with populations of wild trout is the result of several factors. The combination of improved land use in the watersheds that drain into the streams and the land use immediately along the streams has led to improved physical characteristics in the stream itself.
Soil eroding into streams and the increased nutrients that often go with the soil have a large impact on trout populations. Conservation reserve and conservation buffer strip programs have greatly reduced the amount of soil and nutrients entering trout streams. Stream bank stabilization and the placement of trout hides have also reduced the amount of these materials.
The proper management of the watershed, riparian zone, and stream banks results in less soil and nutrients entering the stream. Cleaner streams with a higher amount of clean gravel and rock substrate mean more quality spawning areas for trout. It also results in more diversity and higher numbers of aquatic insects, the primary food of trout. Bank hides and other types of trout habitat improvement mean more places for trout to hide and live.
These improvements have resulted in the increased success of spawning trout in our northeast Iowa streams. And eventually more wild trout to be caught by anglers.