The bighead carp is a plankton eater (microscopic algae) native to Asia. They were introduced into the Mississippi River when private hatchery ponds were washed out in the state of Missouri. They quickly began spawning in the Mississippi and populations spread to other Iowa Rivers. These carp have also been found in the Chariton, Iowa, and Des Moines Rivers. In fact, bighead carp were quite numerous in the Chariton River below Rathbun Dam. Netting studies in the Mississippi River conducted by the Illinois DNR have found that bigheads school with paddlefish and may compete with the paddlefish for food. Since bighead eat microscopic food, it is feared they will also compete with young larval native fishes for food. They can get quite large, with individuals over 60 lbs. having been collected.