Time to sever ties between the Great Lakes and the Mississippi river.
The 14lb salmon was caught in July on Lake Michigan out of Waukegan Harbor, Illinois.The Great Lakes support multimillion dollar recreational and commercial industries.Robert Holthusen.
The Prairie State is bordered by two of the world's most extensive aquatic systems.Lake Michigan is the fifth largest lake in the world and we have a connection to the rest of the Great Lakes system.The Mississippi River is bordered on the west by nearly half of the United States.The whole of Illinois is within the Mississippi drainage, since all of the other waters from the state wind up in the Big Muddy.
Prior to 1900, the two systems were not directly connected.They were very close to each other in the southwest suburbs of Chicago.The upper Des Plaines River and the West Branch of the Chicago River were separated by a narrow drainage divide.The land divide made it difficult for fish and other aquatic organisms to move between the Great Lakes and the Mississippi River systems.
The Chicago Sanitary and Ship Canal, which reversed the flow of the Chicago River and allowed the City to flush its waste into the Mississippi basin, was completed in 1900.That function is still served by the extensive Chicago Waterway System.Significant recreational boating and commercial shipping is supported by it.
hindsight allows us to see that connecting the Mississippi Basin with the Great Lakes system was not a good idea.Doing so allows aquatic invaders to move between them.
The zebra mussel and the round goby are two small organisms that have made their way into the Mississippi basin from Lake Michigan.Control measures for zebra mussels alone cost millions of dollars each year because they cause irreparable harm to the ecosystems where they are introduced.
Invasive fish from the Mississippi toward the Great Lakes have caused more concern in recent years.The silver carp can weigh up to 60 pounds and leap high out of the water when disturbed by boats.Beyond the fact that these guys can wreck a day on the water for boaters, they wreck the ecology of waters they invade and wreck tourist and commercial fishing industries.
Electric barriers have been put in place to keep Asian carp out of the Great Lakes since the threat was first recognized more than a decade ago.It is doubtful that any such measures can do the job over the long run, and already adult fish have been found beyond the barriers twice.
The best way to keep Asian carp out of the Great Lakes is to reestablish a land divide between them and the Mississippi Basin.The spread of nuisance species in both directions would be prevented by a divide.