This may well be reactionary, but if we miss a window of opportunity to stop them, we risk a complete change of the great lakes eco system.  These buggers eat a ton, and get quite large.  It would affect all species.

To the economic effects, the issue in in the Illinois region cost is one of transportation.  the businesses affected have rail and roads already, so the closing of those locks is minimal.  The cost increase is based on transportation differences.

While I agree that nature has its own plan, I would remind you that this fish has no natural enemy in the region... except us.