Biologists and fishermen will use commercial fishing nets and electro-fishing to search for Asian carp over the next two to three weeks.
The Illinois Department of Natural Resources and the U.S. Fish and Wildlife Service will enlist help from the fishermen as they conduct sampling in Chicago-area rivers and canals.
They're looking for carp that have made it past an electric fish barrier system. The barriers are designed to keep carp out of the Great Lakes, where officials fear they could disrupt the food chain by starving out other fish.
While DNA samples suggest that carp have breached the barrier, no physical fish has ever been found.
Weather permitting, the sampling will begin tomorrow.