Wednesday, 2 October 2013

Ambush Tactics - close, personal and a little dirty

Following last week's post in which I talked about ambushing a cock fish for the Friday's supper, some readers asked me to expand on ambush tactics and their application.

Critical Factors

Ambush tactics are not universally applicable and their success depends on a combination of factors coming together.   You are more likely to find suitable ambush sites on medium and small rivers like the Upper Findhorn and the Ettrick Water.

They work best in the autumn, because the increasing urgency of the salmon's reproductive urge will lead fish to run in daylight through water that they would only ascend at night earlier in the year.  There are more fish present in the river and the running groups are consequently larger.  Taken together those influences can make the fish edgier, more excitable and more likely to take.

Wade's Pool  +18"
16th September 2013
The water needs to be low enough to create narrow defiles that concentrate the fish onto a single tight line.  This picture shows a pool at full running height, at which the fish can deviate widely from the primary running line across a broad front.  There is only a faint possibility of your fly crossing the 22m width every 90 seconds intercepting a fish moving upstream at 1m/sec and with a forward look of 1.5m at most.  Actually, given those assumptions it's theoretically 1 : 720.  However, that's before you apply a probability of a take, which at say 5%, makes your odds about 15,000 : 1, which explains why fishing the short halt lies is more productive in those conditions.

Wade's Pool +10"
17th September 2013
Now come forward 24 hours with falling water, albeit there's still ample for autumn fish to run in daylight.  You can see how the viable running space has reduced by around 75%.  In addition, owing to the ease of the wading from the near bank, HMCX was able to fish it at a much narrower angle than was feasible the day before.  This meant that not only did his fly spend longer in the red zone, but also small mends more than doubled its dwell time.  This would have cut his odds to about 150:1, but for the fact that there were not yet any fresh runners coming past him.

The other factor is gender: the great majority of the fish I've caught in ambush have been cocks.  Indeed, in one of the locations pictured I've taken 4 from the same defile in the past 3 years.  It's probably the testosterone-based aggression that makes them readier to make a snatch at an object entering their space.  However, the fly doesn't need to be especially large or bright to achieve the effect, just proportional to the depth, speed and clarity of the water.  That said, there are no hard and fast rules.  In 2011 experimenting with a Sunray Shadow in ambush mode I caught a cock on the first pass, then handed over to Tim who hooked (and lost) a good fish with the next cast.  The moral of the story is that if they're taking, they're taking.  The purpose of ambush tactics is to increase the chance of a fish seeing your fly.

There's one drawback with ambush tactics.  They need time and space.  You won't be popular if you try this on a river with a lot of other anglers who need you to be marching downstream at one pace per cast to avoid a serious traffic jam.

Finding the spot

Corybrough Run +12"
Some ambush sites, like the examples used in this post, are relatively easy to spot. Others are more subtle and take time to work out.  In this instance on Corybrough the defile is at the bottom, not the top, with a neck in the running line about 20m downstream, as shown in the zoom section below.  Although the width looks the same, the running section contracts from 14m where I was stood to no more than 6m on the outside of the flow curve.  By sheer chance I pressed the shutter at the instant a fish took in the defile.

Corybrough Zoom Detail

The fact that I lost the fish highlights one of the drawbacks of ambush fishing.  Because you are working at narrow angles in order to stay in the running zone, a lot of your takes will be head on with the hook lodged near the front of the jaw.  Compared to the take and turn away of a fish in a lie, the frontal take of a running fish is not a recipe for a good hook hold.

Smaller waters like the Ettrick provide a feast of ambush sites, but many of them are not immediately obvious.  You have to remain alert and read the water below you as you advance down the beat.  In October 2010, with the river at a comparatively low +6", I was fishing down a nice straight narrow section with a broad running line just over the centre of the flow.  However, at the bottom of the section the river took a 45 degree right turn.  When I was about 25m above the bend I paused to work out where the running line might be at the start of the curve, and concluded that it was in a narrow channel, no more than 2m wide, about 2m out from the far bank.  I needed the fly to get down quickly and stay down whilst keeping it in the run with small mends.  This meant a small weighted tube, and you can see the Ally Conehead that took the fish (it had to come out of the water as I was up to my knees with a steep bank directly behind me).

Ettrick Water - Bush Pool
But you sometimes have to look hard and think carefully to identify the best place to stage your ambush.  This is another example from the Ettrick on the same trip in October 2010.

The fish run up a broad section, but as they enter the bend the gravel spit at A pushes them towards the near bank, on their way to ascending the fast water at C.  The holding lie at B between the centre line and the far bank can be productive, but it's difficult to present the fly well owing to obstacles on both banks.  You arrive at this pool on a path from the road directly across from B, but it is essential to do a reconnaissance and make a plan to get the best out of this section rather than just starting at C and fishing mechanically downstream.

The really interesting point is at D where the gravel bank A squeezes the running fish into a narrow defile no more than 2m wide at exactly the point where they have to turn sharply across the flow to get to B.  This brings the great bonus of giving  the fish an oblique view of your fly, which is far better than end-on.  Unless you take time on first arrival you wouldn't spot this feature until you were standing on it and amongst the fish running through, where at point blank range on a raised bank you are painfully visible to all comers.  Watercraft is vital on small rivers.

After 5-10 minutes of thought the plan was to fish B from C (no result) and then D at a very shallow angle from opposite B.  After 2-3 minutes of swimming the fly in the narrow channel a large cock fish of 12-14 lbs followed the master plan, took and proceeded to charge all over the pool for the next 10 minutes.  Unfortunately I was in too much hurry to clear the pool to allow my fishing partner to repeat the trick, applied excess force and melted the knot at the eye whilst bringing him to the net (hence no photo).  At least I didn't lose the tube as it stuck on the blob of congealed nylon, but I should sooner have had the fish: lesson learnt.


Triggers - why and when

At this time of the year fishing the short halt lies is generally productive, especially as the numbers and concentration of fish rise.  As the numbers of fish in a lie increase so the chances of a take improve more than proportionately.  But there will be times when, for whatever reason, the fish get on the move almost en masse.  One moment there are fish showing, lots of visible activity and you're catching.  The next it goes stone dead.  If there's enough water to run, it may just be that they've decided to take off.  We can't be certain of the stimuli or their combination. On the Friday at Tomatin this year there was a small lift - no more than 2" - of good fresh water that marked the transition from taking to running.  I'm not asserting that was the cause, just noting the coincidence of timing.  I was happily fishing the main lies in Dalnahoyn Pool: when I arrived around noon there were fish showing.  Shortly afterwards they stopped; the note of the water changed; and I could see the small rise on one of my marker stones.  I judged that they were doing something else, and put my money on that being running.  I'll never know whether I was right or wrong, but the decision did yield a fish.

Practical Application

Dalnahoyn Pool +8"
Noon Friday 20th September 2013
Here is the pool at noon that day.  The viable running area is very large: the near edge of the red zone is waist deep.  The primary running line is just beyond the middle and passes through 2 holding lies.  Lie A, identifiable by the 'Y' where the 2 flows meet, is large and consistently productive.  Lie B is smaller and tends to be occupied for very short halts by fish pausing briefly before entering the fast water, which at the exit is only 2 metres wide.

The first stage involved wading out close to the centre line just above '2' to fish the narrowest part of the defile.  This involved casting at a very narrow angle and applying frequent small upstream mends to keep the fly in play for the maximum proportion of the time.

Next I made my way back towards the home bank at about 45 degrees, covering Lie B. This involved a slightly wider casting angle and bigger mends.

And third, following a line parallel to the bank down to the large dark rock to cover Lie A.  At this stage the casting angle was closer to the conventional 45 degree norm, with no mends and a slow strip.  There was no sense in going much beyond A to chase widely dispersed running fish at odds around 20,000 : 1.

In an ideal world the 4th stage would have been to fish the entry points at the tail of the pool after the long shallow run up from Wade's. However, there are several, spread across a broad frontage, which expands the odds; it takes some deep and cold wading to cover them properly, which takes time; they are interspersed with some awkward rocks, with the consequent risk of snagging and more time lost; and time was not on my side.  I had 90 minutes left until beat rotation in which to deliver a fish to the cook, which focused the mind admirably.

Dalnahoyn 1pm 20 September 2013
So I went back to '2' for a second iteration.  Shortly after starting the oblique wade back inwards a fish took just upstream of Lie B.  Of course it was a fluke; they all are, but I flatter myself that my choice was vindicated by improving the odds, which is what ambush tactics are all about.


  • Try to remain alert and aware of even small changes in your environment such as water tone and level, light, temperature and weather, all or any of which may influence salmon behaviour.
  • Remember that by the autumn the salmon's reproductive alarm clocks are ringing loudly, which makes running a more urgent activity and the fish consequently bolder.
  • From birth the salmon is a social shoaling fish that prefers to run in company.
  • An abrupt change of behaviour or 'feel' in an otherwise benign environment may indicate a transition to running.
  • If the evidence suggests that is the case, the odds tell you to switch tactics from area coverage to point ambush.
  • Look closely at the water you are fishing to identify run lines, transitions and defiles that offer suitable ambush sites.  Even if you don't need the information today, store it for future use (see Reading Railway Maps for more detailed advice).
  • Don't rush: do a reconnaissance, think and make a plan for fishing each stretch, but be prepared to change the plan as better information emerges.
  • Don't fish mechanically with a preconception of casting angle: be flexible and ready to adapt to changing conditions and emerging opportunities.
  • Get the fly into your chosen defile and keep it there using small mends; turn your casting switch to the mute setting.
  • Add ambush tactics to your armoury: they may yet save your supper!

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