Massive fish death is planned for the Chicago Sanitary and Ship Canal, historically known as the Chicago Drainage Canal, in northern United States.

Starting early next month, authorities will inject the powerful fish poison Rotenone into a five-mile stretch of the canal; from Lockport Locks to the electronic barrier system near 135th Street in Romeoville. The government wants to stop Asian carps from entering the Great Lakes while one of the electronic barriers is shut down for routine maintenance.

Completed in the year 1900, the canal is the only shipping link between the Great Lakes and the Mississippi River system, and the aim of the mass killings is to save the Great Lakes ecosystem from the Asian invaders that have found their way into the manmade waterway.

Two species of Asian carp – the bighead* and the silver** – were imported by catfish farmers in the 1970′s to remove algae and suspended matter from the catfish ponds. During the early 1990s, large floods in the area made farm ponds overflow, giving the carps a chance to escape into the Mississippi River basin.

Since then, the carps have steadily made their way up the Mississippi river and are today the two most abundant species in parts of the system. They outcompete native species and cause starvation in large native game fish by devouring such large amounts of plankton.

Introducing rotenone to the canal will kill all fish, not just the Asian carps, and this has naturally stirred up some controversy. The poison is said to be safe to people, pets and other wildlife in the area, but no one should eat any fish killed by the chemical.

The plans to poison the canal were announced during a special telephone press conference Friday afternoon with members of the Illinois Department of Natural Resources, the U.S. Army Corps of Engineers, the U.S. Coast Guard and the United States Environmental Protection Agency.

This plan has been developed with input from many biologists and scientists who all agree this is the best course of action,” said John Rogner, assistant director of the IDNR. “All of the (dead) fish will be removed and disposed of in our landfills. The clean up will take a couple of days and the cold water should remove any odours.”

Electro-fishing techniques will be used to remove and relocate as much game fish as possible from the canal prior to the release of the poison, and there are also plans to restock game fish in the area afterwards, as soon as chemical accelerants have been applied to remove the rotenone from the water.

* Bighead carp (Hypophthalmichthys nobilis)
** Silver carp (Hypophthalmichthys molitrix)