Tuesday and Wednesday of this week I attended the Minnesota Water Resources Conference. This conference is put on by the University of Minnesota’s Water Resource Center. The topics vary from lakes and wetlands to low impact development, outreach, fish and nutrients. The event was attended by more than 500 individuals from varied backgrounds.
One of the most interesting talks was a Plenary Session by Peter Sorensen, a professor at the University of Minnesota’s Department of Fisheries. He discussed the introduction of common carp into the United States in the late 1870s. After the introduction from Eurasia, common carp spread quickly throughout the United States. All carp are invasive species. Professor Sorensen talked about the efforts to control carp and the biological reasons these efforts failed.
The University’s research on carp has expanded the understanding that we have of the carps behaviors and movements. Professor Sorensen stated that you are, “not going to restore a shallow lake until you do something about carp.”
Carp are bottom feeders and can disturb and feed on the top six inches of lake and river bottoms. Their mouths are complex feeding machines that filter out small bits of food and move the sediments back into the water causing high nutrient and highly turbid waters. Carp uproot aquatic vegetation and degrade habitat and water bodies.
Carp are highly mobile in watersheds and the University found through tagging that they move into areas like swamps and marshes more often then anyone ever thought. Even though carp have been in Minnesota for more than 100 years, their impacts on water quality are not yet fully understood.
Professor Sorensen highlighted that this whole process of introducing carp was repeated in the 1970s with Asian carp. Many of the failed control methods are being used again. Carp and other invasive species have disastrous impacts on Minnesota’s water quality. Urban and rural waters are impacted by carp. While not a part of the natural background, their effect on water quality through disruption of sediment and nutrients is not clearly known.
Carp are one issue that rural and urban communities will have to work on together to help clean Minnesotan waters.