Let the poisoning begin...

In an attempt to prevent big, icky, voracious Asian carps from making it into Lake Michigan the Illinois Natural Resources Department is releasing a fish toxin into a stretch of the Chicago Sanitary and Ship Canal.

God speed, poison!

The fish kill is expected to cost as much as $2 million and kill thousands of fish. It is designed to give the Army Corps of Engineers an Asian carp-free window of time to perform regular maintenance on the electric barrier the corps installed to stop the Asian carp from traveling toward the lake.

Asian carp -- which can weigh as much as 100 pounds, grow to 4 feet long and have been known to jump onto water-skiers and into boats --are expected to return to the barrier after the mass poisoning.

The voracious eaters feed on the low end of the food chain -- such as plankton. They wind up squeezing out fish that bigger fish feed on, potentially devastating sport and commercial fishing.

"You don't use rotenone unless you have no other options," said Marc Gaden, spokesman for the Great Lakes Fishery Commission. "Our backs are clearly against the wall here. ... This is pretty much the last chance, and this is a significant step we are taking."

Fish experts from around the Great Lakes region, including Canada, will coordinate pouring the liquid toxin into the water Wednesday afternoon. Hours later, the carcasses of thousands of fish including goldfish, gizzard shad and common carp will join the Asian carp in rising to the surface before being hauled to a landfill.

The shipping canal will be closed to boat traffic starting Wednesday and lasting through the weekend.

Rotenone naturally detoxifies, though the neutralizing agent potassium permanganate will be added to the water after the poison does its work. The fish toxin will be poured in the water roughly from the electric barrier down to the Lockport Lock and Dam.

"Is there a possibility there may be some small residual fish kill beyond the Lockport lock? Yes," said Chris McCloud, Illinois Natural Resources Department spokesman. "But we are prepared to deal with that and keep it in as tight an area as possible."

The routine electric barrier maintenance needs to be performed twice a year, and it's not known if another expansive fish kill will be needed six months from now, McCloud said.

"It's not something we hope to do," McCloud said, adding, "We need to focus on this particular operation."

Despite the efforts to keep the Asian carp out of Lake Michigan, Asian carp DNA has been found upstream of the electric barrier, suggesting that a few fish got past the electric barrier and are headed toward Lake Michigan.

Gaden said the fish kill is an absolute necessity to keep the Asian carp in check.

"Not doing it is throwing in the towel and inviting a species that is going to be very destructive into the Great Lakes," he said. "The economic costs of these fish to the ecosystem would be tremendous -- unquantifiable and irreversible."