Mud and debris flushed into Lake Superior from Duluth rivers and streams. Photo Credit: David Cowardin / Duluth Outdoors
Photo Credit: Andrew Chadwick
By Manda Lillie
For Duluth Outdoors
As rain overtook the city of Duluth, excess water from streams and rivers was washed into the lake. With it went the fish.
According to Mark Gottwald, Supervisor of the French River Hatchery, the “north shore streams tend to carry fish as a nursery, then they become big enough and head to the lake.”
Gottwald also said the fish may have survived the turbulent waters, but no one will know for another year or two.
Most of Duluth is built on clay. Clay absorbs water, but only so much. After that point the water flows over it. “The rivers flow right for a reason,” Gottwald said.
Debris also made its way into the lake. Gottwald cannot speak for the fish in Lake Superior and the impact the debris has on them. However, the fishery draws water from the lake.
When these things happen we end up sucking up a lot of debris and sediment. We have to be very careful with our fish for a day or three, can’t feed them or anything.
Cindy Hagley, environment quality educator for Minnesota Sea Grant, said that debris and sediment can drastically change a fish’s habitat. “[Extra] sediment in the water is difficult on native fish,” Hagely said. “It can clog their gills and be deposited on the bottom with where they lay their eggs.”
Hagley continued, “Depending on the type of fish some can just get away from the negative impacts on the water.”
However, younger and smaller fish would have a difficult time navigating the waters. Brook Trout would also struggle because they are not strong swimmers.
Shore line erosion also brings debris into the water, said Hagley. Also, if vegetation is washed away there is nothing keeping the sediment back during the next storm.
