Watch this video from 2006:
http://www.youtube.com/watch?v=2ChwJiKKBdA&NR=1 Fast forward to 2009, the Asian Carp were just detected upstream of the Brandon Road lock and dam on the Chicago Sanitary and Ship Canal. This is serious because there is only one lock left, along with the electric fence you see in the video, until they are in Lake Michigan.
Presently, the electric fence is only at 1/4 power so that ships and boaters on the canal are not zapped. It is believed that at 1/4 power, adult fish are repelled but juvenile fish are not.
I hope they give the electric fence full juice since one lock is not much protection for all of the Great Lakes.