Bois de Sioux fish kill linked to Lake Traverse outflow reduction
FARGO - A fish kill on the Bois de Sioux River in July was caused by a chain-reaction that began when the U.S. Army Corp of Engineers cut outflows from Lake Traverse, a Minnesota Department of Natural Resources official said Tuesday.
When dead carp began piling up near Wahpeton, N.D., around the Fourth of July, the DNR collected dying fish and had them analyzed.
Results show the fish died of a columnaris bacterial infection, said Arlin Schalekamp, a DNR fisheries supervisor in Fergus Falls.
Schalekamp said the fish fell victim to infection because they were stressed by high water temperatures and low river levels, a situation exacerbated by the White Rock Dam shutting down flows out of Lake Traverse.
Schalekamp said the DNR plans to talk to the Army Corps, which operates the dam, about what happened.
"We don't like to see the flow cut off. It's not good for organisms in the river. They can't adjust to that," Schalekamp said.
Tim Bertschi, a spokesman for the Army Corps, acknowledged Tuesday that the shutoff "kind of stranded these fish."
The action was taken because the lake had reached its normal summer level, said Bertschi, who added shutoffs are usually done gradually to avoid dramatic drops in river levels. A decision was made in July to reduce the flow somewhat abruptly to avoid silt buildup beneath the dam, he said.
He said the shutoff is normally completed sometime in May, but it was done later this year because of the wet spring.
Bertschi said the Army Corps plans to meet with state officials to talk about how the situation was handled with an eye toward avoiding problems in the future.
"We're going to sit down and take a look at that," he said.