A local fisherman actually described it that way.  Spawning salmon don’t come after bait.  They are not eating anymore.  So how do you get them to take a hook?  It’s all in the wrist!  They cast up stream, let if float with the current across the ever opening and closing mouths of the hard swimming salmon and quickly draw the pole back to shore sliding the line through the fish’s mouth….tada, fish on.   You can’t keep one snagged anywhere else but as long as you snag them in the mouth its ok.  Hmm, that’s sport fishing?