Sneak of the week

[Tartar Horde]

Mort, the fish absolutely know what fishing line is, and that there is an association between that and getting caught.
The thing you need to appreciate is that nearly all our fish are thrown back and not eaten. Over the years they become accustomed to fishing and so become "hook shy" this is why I need to use fine line tactics to overcome their suspicions. If there are any Carp anglers on this forum they will confirm to you that fish do very much notice line, and certainly notice the angler if water conditions are clear enough.
The reason you stateside can use a more agrarian approach is that the first time a fish sees a hook in the US, is its last, they simply don't get used to being fished, and never live to learn from their mistake.