Vernon County Manure Spill Could Impact Local Trout Fishing

A recent manure spill in Vernon County could have long-term impacts on a popular trout stream.

The Wisconsin Department of Natural Resources responded to a manure spill at Wild Rose Dairy last week. The agency reported the spill killed more than 1,100 fish in Otter Creek, including brook and brown trout.

DNR officials declined to provide more details about the spill, citing an ongoing investigation.

David Rowe, DNR fisheries team supervisor in Fitchburg, said a recent survey found about 1,100 trout per mile of Otter Creek.

“Picking up the amount of fish they did wasn’t good,” Rowe said.

Rowe estimates there are up to seven manure spills every year in his nine-county region. After a spill enters a waterway, he said there is an acute impact.

“The biological oxygen demand in the stream goes way up because all of the bacteria that are basically digesting that manure also use up the oxygen in the water that fish or bugs would be using, and so you have a really low dissolved oxygen level which causes the quick fish kill,” Rowe said. “The second thing that can happen is you have ammonia that’s contained within the manure and that ammonia is toxic to those aquatic lifeforms and that ammonia exposure usually causes a two- to three-day later response.”

And environmental advocates worry there could also be long-term impacts to the trout population.

Jeff Hastings is project manager of Trout Unlimited’s Driftless Restoration Project, an ongoing effort to help restore trout habitats in southwestern Wisconsin. He said manure spills affect all age classes of trout.

“Your most productive fish will likely be killed in such an event. These populations have to self-regenerate, some fish will survive and will start repopulating but it takes time,” Hastings said.

Hastings said it can take years for oxygen levels to return to normal in some cases, impacting the future of the fish population.

Ole Yttri, clerk for the Town of Webster where Wild Rose Dairy is located, said he’s hopeful the manure will not impact other waterways in the area, including the Kickapoo River.

“We had a lot of rain last week also, 3 to 4 inches of rain in this area, so I would think this would help dilute the water system,” Yttri said.

Yttri said trout fishing is a valuable resource to the community and county.

A recent study estimated trout fishing brought more than $1.6 billion dollars in tourism revenue to southwestern Wisconsin and neighboring states last year.