It's very important when you're salmon fishing on a Scottish river to deploy effective riverbank movement spacings between each cast.
One of the most important salmon fishing skills that is not taught or even fully understood by the vast majority of salmon fishers is 'effective riverbank movement'. Many anglers inch their way through a salmon pool wasting much valuable fishing time and technically training salmon to accept the presence of their fly (or lure) in the stream. To make a salmon take you need to trigger its hunting instinct and that is logically best done by startling the fish via good riverbank cast spacings. 1 yard (3 feet) between each swing of the fly has worked very well for me, my guests and fellow salmon fishing guide team members over the decades (when spin fishing a 10ft spacing between each cast is an equally effective movement strategy). Book a professional Scottish salmon fishing guide to learn this vital skill and many others for consistent success in this sport.
On the River Tay a form of 'backing up' downstream trawling referred to as 'harling' is deployed to cover the generally wider & deeper Tay. With this Tay boat fishing method typically 3 lures or flies are tactfully presented at varying lengths over the salmon lies which almost creates complete 100% watercoverage over just about every square yards of water if the boat is under the control of a skilled and experienced Tay boatman. This really also boils down to effective watercoverage if you really think about it and as mentioned above this can be replicated by a riverbank fisher who's deploying good methodical and consistent fly swing spacings between each cast.