Same pool, same level but different water
In Part 1 I asked you to look at both height and clarity. The 2 photographs below show a pool at nearly the same height, but the fishing conditions are markedly different. This is the Flesh Dub pool on the Bolton Castle water on the River Ure in North Yorkshire, which is highly productive throughout its length. The photographs are separated by a fortnight this spring: the common feature of both days was the wind, gusting 30+ mph straight downstream, which made standing up a challenge and casting something else again (thank you Skagit).
In Picture 2, taken 2 weeks later, the water is about 6" lower, but the fishing conditions are markedly different. The river is falling and clearing: you can see the bottom in the foreground. The flow rate is still brisk, but closer to medium than fast. The sky is clear and the ambient light average to bright for the time of year. The water temperature is 50F/10C. These conditions would score around 8, which is the realm of medium sized flies and slow sink tips, depending on the depth.
This exercise underlines the point that it is not simply a question of the height of the river, but rather a range of factors that you need to take into account. The scoring system isn't precise or prescriptive: it isn't meant to be, because its aim is to inform judgement rather than taking the decision for you.
Depth - the critical factor
Here's the same pool, zoned for depth at a level 18" above summer low. The deepening shade represents increasing depth. Head to tail is some 300m/350 yds.
The lightest blue is water less than 3' deep: in the foreground and far tail it's as little as 15-18". Salmon will happily move through this depth of water, but will not stop for long in daylight owing to their embedded fear of avian predators. Takes tend to occur in this zone only when good numbers of fish are running from July onwards.
The mid-blue area covers the range 3'-5' deep, which provides ample security for non-resident fish (i.e. those taking a pause during running). This is the most productive part of the pool because it is where running fish halt and rest in response to the hazardous shallow water ahead of them. Remember that the salmon does not have our viewpoint or long range vision: in these water conditions they have a reasonable view out to about 8-10'. They can sense the turbulence of the shallow water through their lateral line nerve endings at much greater distance and so will only approach it cautiously, if at all in bright conditions, especially early in the season (this is based on documented Norwegian research, not my opinion). You can cover the mid blue zone effectively with an intermediate or slow sink tip and a medium sized fly around #8 or 1" plastic tube, presented about 1' below the surface. The key driver here is water temperature: if it's cold you have to get deeper and closer to the fish; if it's warm a fluorocarbon leader may suffice.
The dark blue zone is the small part of this pool that is over 5' deep. As I indicated in Part 1, if you are going to fish it effectively you will need to re-rig. However, depth is not the only reason here, because in Flesh Dub this is the preferred sleeping quarters of 'resident' fish. These salmon run to a particular spot and then for whatever reason, stop, switch off and go dormant (there's a fuller explanation in the earlier 'Where are They?' post). In my experience these are the hardest fish of all to catch. Some of them arrive as early as April. To make matters worse, they tend to be big. Periodically they wake up, become active for a short period, stretch their fins, tease us with a splashy roll and then retire to sleep again. If you do not coincide with their short active periods, then to have any chance of gaining their attention you need to get the fly closer than normal and fish it at a speed that allows them to wake up and take it within the 'envelope'. An alternative approach is to use a stimulating fly like the Sunray Shadow. But remember that there are no guarantees in this business, and if the take happens you and the salmon will be equally surprised (as was the 15 lbs hen dozing behind the rock in the shadow of the big willow tree on the right hand side).
Another pool - same level, different waterCompare the 2 shots below of the Garden Pool on the Tomatin House water on the Upper Findhorn. Again, the level is similar, but the character is different.
This shot is mid-September 2010, looking upstream in mid-afternoon, with the river at +18", falling and clearing, in pleasant sunshine. The water temperature was around 52F/11C. It looks absolutely perfect (and there were fish in the river) but I failed to connect, almost certainly as a result of the bright conditions gulling me into fishing too light and shallow with too small a fly. In retrospect, if I had applied my own formula (score 8/9), the slow sink tip and a 1" tube would have been the choice.
The same week in 2011: the river is again at +18", but rising fast, albeit still quite clear. Its character is fundamentally different, as was the technique - Cascade conehead and sink tip - guided by a score of 10.
For those who have spotted this photo sequence previously, please be assured that it was not the only salmon I caught in 2011. But it's the only time I've ever achieved coincidence of salmon, wife and camera!
SummaryI hope that this post has underlined the value of thinking methodically and treating all the factors systematically. Certainly my failure to connect on a perfect day in 2010 when other rods were catching plenty of fish delivered a sharp lesson (and blow to my self-esteem). On that basis it's worth pondering why not as much as why, whilst always remembering that it's the salmon who decides.
In the next post - Part 3 - I'll look at some tricky pools that provide challenges to how we present the fly (and to my 3-D graphic skills).