Carping in Chicago

Yet another story of invasive organisms (http://www.guardian.co.uk/environment/audio/2010/feb/24/asian-carp-threaten-great-lakes). The Asian carp is a fresh water species that can hoover up some 40% of its own body weight in plankton and algae per day which means that its actions starve the young of many other fish species. The carp was apparently introduced in the Southern states of the USA from China to help clean fish farm tanks. Somewhat predictably, they 'escaped' into the Mississippi river and have worked their way north, decimating local fish stocks, to the Illinois river just outside Chicago and in striking distance of Lake Michigan. This is a particular problem as, in 1900, Chicago engineered a reversal in the flow of its river and built a canal enabling millions of gallons of waste water to be sent downriver. This had the effect of linking the Mississippi river to the Great Lakes (said to be the world's largest fresh water body). People are concerned about what will happen if the fish enters Lake Michigan and a number of the involved states are pressing for the locks on the canal to be permanently sealed. The city of Chicago, which still enjoys some shipping activity, is not happy with this suggestion. I think that the fish will almost inevitably make the 'leap' to the next ecosystem.