The channel is the problem with the ballast water.  And that comes with a threat of increasing costs for the people who use the channel and have $7 Billion of economic impact. (in Chicago) That  closing the channel however does NOT eliminate their impact however, because they have options of using rail.  It costs more for rail.

So for some its a tough call.

BTW the impact on the sport fishing, recreation, etc., is potentially about $80 Billion on the economy of the great lake states.

Finding carp (and it is not a straw man - YOU brought them up) is harder than pigs.  And evidence of their feral activity makes it easier to track them.

The DNR is WAY off on this one.  The invasive sets are too broad.

And BTW