It’s been decided. The final effort to prevent flying carp from entering the Great Lakes is about to begin.

The U.S. Army Corps of Engineers is planning to close the Chicago Sanitary and Ship Canal for five days starting December 2 so they can release a toxic substance into the water to kill invasive Asian carp.

State and federal agencies acknowledged Friday that DNA tests show Asian carp have evaded a two-part electric barrier intended to prevent the fish from gaining access to Lake Michigan, and eventually the Great Lakes ecosystem, through the canal, a man-made waterway that provides a direct hydraulic connection between Lake Michigan and the Mississippi River Basin.

Scientists and government officials agree the invasive fish pose a serious environmental threat to the Lakes because of their size and voracious appetites. The two invasive species – bighead carp and silver carp – can grow over four feet long and 100 pounds and quickly take over habitat upon arrival. In the Illinois River, they now make up 90 percent of the life forms present in some stretches of the river.

Poisoning a body of water is a drastic step, but if the alternative is that sometime in the future 90 percent of the life in the Great Lakes could be flying carp, bring on the poison.