Asian Carps in Illinois

by Pier-Alexandre Hudon

 

 

What are Asian Carps?

 

To start, the term  «Asian carp» includes four species: Bighead, Silver, Grass and Black carps. Bighead carps were brought to North America in 1972. Black carps were brought in 1970. Grass carps were brought  in 1963 and Silver carps were brought in 1973. Asian carps make up more than 50% of the fish in some parts of the Illinois River. They can grow more than 25 centimetres in their first year. The fish typically weighs two to four kilograms, but can weigh up to 40 kilograms and reach more than a metre in length. They can eat up to 20% of their body weight in plankton each day. Finally, Asian carps reproduce rapidly.

 

 

How did Asian carp make their way into Illinois River system?

 

Asian carps were imported from Southeast Asia to the southern United States to help aquaculture. Flooding allowed these fish to escape into the Mississippi River system and migrate into the Missouri and Illinois rivers. The Mississippi, Missouri and Illinois rivers are all connected and allow fish to swim freely between them.

 

 

Why are they a problem in the Illinois River system?

 

The diet of Asian carps overlaps with the diet of native fishes in the Illinois River, meaning the carps compete with native fish for food.  The silver variety of the Asian carp has caused direct harm to people. They are easily startled by the sound of a boat motor. The sound can cause the fish to leap as high as a feet out of the water and they can land in boats and injure people.