Professional career Scottish salmon guide advice on the best logic based salmon fishing tactical approach during the very cold early Spring months.
There's a lot of misinformation written by anglers who think they know the behavioural habits of salmon just because they've previously read information in books written by authors who are meant to know but haven't been professionally involved to really know the true facts. The reality regarding Scottish cold water early Spring salmon behaviour is really quite simple to understand and highly logic based as are most tactical approaches in Scottish salmon fishing.
In the very early months of the year when there are frozen riverbanks and the air & water temperatures are hovering not too far away from freezing point salmon that do enter or run the river are always motivated to do so on days where the low Winter sun places just enough warmth on the top area of the water column (and on salmon's backs) to encourage salmon to run. As a former professional River Tay boatman I'd relate virtually all eary Spring salmon captures to days when the low Winter sun was shining brightly as that was a sure indicator to me that salmon were on the move due to the sun's warmth on the surface of the river.
The warmer thermals in any water column are naturally found in the surface foot or two and below that remains colder water so you don't need to be a scientist to know what I've just stated is indeed factual. So when early running Spring salmon decide to leave the warmer ocean temperatrures and enter the very cold river water they're looking for a similar water temperature or at least the warmer thermals found in the upper river water column as you can clearly see in this accompanying video where 2 Spring salmon are holding 1ft to 2ft under the river's surface.
In the cold river water of early Spring targeting the top foot or two of the water column will give you the best chance of success (despite the nonsense written about fishing very deep in cold water conditions). That myth of fishing 'deep & slow' (should be 'high & slow') in very cold water conditions was derived purely from salmon anglers not understanding the 'jacking up' effect the river current has on their sinking fly lines which they assumed was sinking their flies much deeper than they actually were when they previously hooked salmon.
In addition to this you should be fishing a 'slower paced' larger salmon fly than you'd fish during the warmer months. A salmon won't charge several feet across the pool in very cold river water and the take from a salmon in very cold water will usually always start much slower and more subtley than the warmer water take equivalent. This is due to the salmon generally being slowed down by the much lower cold river water temperatures. Learn more salmon fishing skills by booking a professional Scottish salmon fishing guide to make sure you receive a good understanding of this kind of essential salmon fishing knowledge and salmon fly presentation skills.