Illinois scientists are estimating that the bighead and silver carp threatening to invade Lake Michigan from the Mississippi River will reach an electrical barrier near Chicago by spring 2003. The real test of the barrier will come when hundreds of these fish line up to challenge the uncomfortable shock felt when attempting to slip through an electrified canal.
Laboratory tests demonstrate that the carp are sometimes able to penetrate electrical fields that simulate the real barrier in the Chicago Ship and Sanitary Canal. Researchers are hoping that the actual barrier proves more effective due to its significantly higher strength. Field tests utilizing a small number of grass carp have not yet shown any penetration of the fully powered barrier.
A committee in Chicago is already moving ahead with plans to build a second barrier in the canal. The new structure will likely combine sound and bubbling water to create a disturbance that repels the carp. This project should be completed sometime in 2004, and will provide extra insurance against species transfer between the Mississippi and Great Lakes basins.
Continuing support of these programs is strongly tied to passage of the new National Aquatic Invasive Species Act. The bill would provide several million dollars in funding and authorize the Corps to continue supporting barrier operations and new construction.