I'm wondering if a little experiment might shed some light on the mono vs fluorocarbon debate. Devise a test which tests a fishes (preferably some fish a person might actually want to catch) ability to avoid fishing line. I thought of putting a fish in a rectangular tank, then making a curtain of fishing line suspended across the width of the tank and see how good the fish is at avoiding the line.
I think I have heard of somebody trying this but repeating it wouldn't hurt especially because fish eyes vary in structure and ability to see in various conditions.