..and to add even more things to the hassle of lure fishing...different lines will have the lure swimming at different depths and different speeds across the current.
Basically, the thicker the line the more drag occurs, the more drag, the higher the lure will swim and the quicker it will move across the current as the flow will catch and push on the line more.
Generally, the heavier the breaking strain of the line, the thicker it will be.
....unless you use a modern co-polymer, pre stretched line or, more importantly, braid. I use 30lb braid which is the same diameter as 10lb line. So, my lures will run slower and deeper as the braid is so thin. BUT, some braids float, which makes the lure run higher...etc etc.
Lure fishing is often seen as a last result, fools way of fishing, but if done right (and I am no expert on Salmon lure fishing, but I can hold my own with Pike and Perch
) it is very skillful and like fly fishing, rods and reels can run into hundreds of pounds and be just as delicate as a fly rod.