In the last post I looked at how to present the fly at the
right depth to prompt a take. We now
turn to the horizontal plane, which comprises first getting the fly to the
right place, and making it behave in a way that may stimulate a salmon to take. However, I am going to take those two
elements in reverse order, because the desired behaviour of the fly drives its
delivery.
We do not know exactly why a non-eating salmon takes a fly,
but let us assume that there is some connection with embedded reflexive
responses. It takes an object into its
mouth because something in the nature or movement of the object triggered a
feeding reflex. No one teaches a salmon
to eat, but their life is characterised by the unrelenting consumption of
protein leading to spectacular growth.
Once the alevin sheds the yolk sac and becomes a fry, it
automatically starts to feed on small invertebrates. A parr eats progressively larger
invertebrates, mostly ephemera nymphs and stonefly larvae. As this blog is about salmon rather than
trout, for simplicity I use the abbreviation ‘nymph’ to include all the different
species and types of waterborne larvae (and hope that the experts forgive me). The time spent as a parr and the amount it
eats embed high-speed food recognition and instinctive response. Salmon are short sighted as a consequence of
their very wide, indeed near-spherical field of view. Survival is not cost free. Parr feeding in flowing water therefore do not
have much time to decide: the slow-witted starve. At this stage of life it needs around 8% of
its body weight daily in protein, which is a lot of nymphs - thousands per month. Consequently the size, shape, tone and
movement of nymphs become printed in the forefront of the young salmon’s brain
in order to achieve the necessary speed of decision and action. Those features are:
Size – small, in the range 3-20 mm
Profile – roughly cylindrical with legs sticking out
Tone – dull, but in the final ascent towards hatching, gas
bubbles on the body may reflect ambient light brightly.
Movement – very slow, in the range 1-5 cm/sec (<
2”/sec): try
timing your finger along a ruler. Most
travel is horizontal and near the bottom, but the ascent to hatch (when their
food value is highest) is upward and thus clearly visible in Windows 2 & 3.
Once the smolt reaches the sea it has a cornucopia of
high-protein prey species. Sand eels and
sprats congregate in huge numbers. For
their part the smolts form shoals for protection from predators; improved
observation and prey detection; and increased hunting efficiency to counter the
prey species’ defences.
The sand eel has a tough life at the top of every fish’s
menu. It is bite-sized, easily swallowed
and high in protein. Once the sand eel
is deprived of its shallow water defence of burrowing into the sand, its 2
metre dash is no defence against smolts or salmon. An adult salmon carving at speed through a
shoal of sand eels may swallow several in each pass, an exercise conducted at
such speed that only reflex can deliver the required coordination of tail and
mouth. Although the sand eel’s range is
limited to shallower waters, its importance lies in being the first and most
plentiful food that the salmon encounters during its early development in the
North Sea and Shetland Banks.
The sprat, which is more widely distributed across the
salmon’s range (the Faroese call them brisling), shares top of the menu with
the sand eel. Better still, it’s even
easier to catch and has exceptional protein density. It’s shorter and fatter than the sand eel,
lacks its dash speed, and forms very dense shoals. A mature salmon might be taking over
1lb/0.5Kg of sprats per day to maintain its growth rate.
The key characteristics of the 2 species are:
Size – in the range 3-15 cm.
Profile – oval, with a large length to diameter ratio.
Tone – grey green with silver sheen that increases with
ambient light. In a grey-green ocean in
winter light it’s lateral movement that gives them away.
Movement – from slow at cruising speed to fast in survival
dash (about 1.5-2m/sec, which is very fast for such a small fish). Movement tends to be in straight lines and
broadly horizontal unless panicked. They
wriggle continuously.
The two listings of characteristics frame the images we probably
need to create in the salmon’s brain in order to trigger a response. From that we can derive how best to fish the
2 generic types of fly:
Small.
The movement
is slow, ideally upwards and interspersed with short pauses. Therefore:
Blue Charm 14 Note legs & gas bubbles in the dressing |
- There’s not much logic in casting small flies into fast water where they will tumble and move chaotically like the rest of the debris coming downstream, and be similarly disregarded.
- Remember that it would take a live nymph 2-3 seconds to traverse the palm of your hand, so slow the fly down to match.
- The fly can only move upwards if it first went down: use a fluorocarbon tippet and/or an intermediate polyleader, but always keep the fly above the salmon’s sight-line.
- At all costs stop a belly forming in the line which will otherwise accelerate the fly to sand eel warp velocity.
- Towards the dangle, slowly retrieve a few inches; pause to
allow your fly to sink back; and then repeat.
Large.
Sunray Shadow 12 cm Off-centre dressing increases wiggle |
- Obey Newton’s Law: you will only get lateral movement and wiggle by applying tension on the line.
- If the leader does not lay out straight at the completion of your cast, take up the slack immediately, otherwise the fly will just hang in the water pointing skywards for much longer than you think. It’s better to fish a smaller area effectively than waste the first third of the swing.
- Eliminate line belly: a fly moving downstream achieves nothing; and a fly at warp speed even less.
Of course none of that guarantees success. But we can help to improve the odds by
eliminating things that are handicaps and hindrances to securing the fluke,
even if a fish with a brain the size of a broad bean will remain
unimpressed for 99.9% of the time.
You may wonder about the Broad Beans in the post's title. This is a sad little story of a failed experiment and
humiliation. I got myself into position
nearly 20 feet above a nice clear pool crammed with plainly visible salmon
milling about soaking up the oxygen before launching themselves at a testing ascent
of the falls behind me. They were all
awake, alert and active. I attached an
exceptionally realistic imitation plastic sand eel, cast beyond the fish and stripped
it back through their midst at the appropriate speed. There was not even a flicker of interest,
despite the eel’s seductive wiggling only inches from their noses. Ten minutes of repetition achieved nothing: their
bean-brains were obviously wholly focused on the task in hand, and any way, the eel was at or below their sight line. I gave up trying. Twenty feet below me at the water’s edge
Patrick rolled a small Stoat into their midst, stripped it back heading
downstream and promptly hooked a nice hen fish.
You can generalise about broad beans, but there’s no two that are
identical. So no matter how confident my assertions may be, remember that it only takes the intellect of a broad bean to prove me wrong!
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