Dark Shrimp's First Swim 22nd August Swimming and visibility trials |
To make matters worse, it's been raining frequently and hard in the Vale of York. Indeed, the remnants of Hurricane Bertha brought our 8 week summer to an abrupt and very chilly end, whilst depositing 65 mm of rain in the process. There's now a real autumnal feel in the air, which of course triggers every cell in my body to think salmon (it's not just fish that have things embedded in their cellular DNA). However, Bertha seemed to skirt Wensleydale, probably as a result of the over-stocking of Yorkshire's collective prayers for the Tour de France to have a Grand Depart Sec. And they were answered! Anyone who didn't believe in our special relationship with the Almighty should have been convinced by the television coverage. As a result we've only had one limited spate of about 1.5 m, which didn't persist long enough to bring many fresh salmon up from the Humber. That put the kybosh on my New Year resolution to catch a salmon on a dry fly, which requires fresh fish and warm water. On the other hand the sea trout didn't feel so constrained and the river's packed with them (of which more shortly).
I could take this torture no longer: water boarding without water so to speak. So when a day's rain promised to put the river up by a few inches, I made my break for freedom. Even though the possibility of catching a fish was very low, a day on the Ure would lift my spirits whilst fulfilling the serious business of conducting the MCX Dark Shrimp's swimming trials. In addition, the accumulation of large numbers of underwater photos would give me more data to calibrate my theoretical Photoshop models. So this post records the day whilst also exposing the visual challenges that confront salmon in a combination of bright light and coloured water (and satisfying my interest in the underwater visual aspects of our sport).
Trial Context
MCX Dark Shrimp #9 |
Frodle Dub looking downstream |
Health Warning. Once again, please note that I am not claiming that these photos faithfully represent what the salmon sees, because we just don't know. We do know the optical characteristics of the salmon's eye, but not how its brain processes the inputs, resolves colour, forms an image or employs the product in its situational awareness and decision making (conscious and/or unconscious). Certainly the salmon's eye has evolved to meet different purposes to ours in a markedly different environment, so it's a reasonable supposition that they don't 'see' like us. For those reasons the purpose of the succeeding photographs is purely relative within the context of the visible red-yellow-blue spectrum: A is more readily detected than B; under one set of conditions detection is easier than in another; one scene is brighter than the next; and the comparative luminance or transparency of the 3 Windows that comprise the salmon's visual environment.
Depth 3'/1m Sun Out Horizontal Direction - South East |
Depth 3'/1m Sun In (cloud) Horizontal Direction - South East |
And this was 10 minutes later when the sun went behind a passing cloud. Brightness, contrast and backscatter are all markedly reduced. By the way, there's no fly present in this shot.
Depth 2'/60cm Sun Out Oblique Direction - South East |
Depth 2'/60cm Sun In (cloud) Vertical |
Dark Shrimp Impressions
As described above, the trial took place in extremely challenging conditions for detectability - the capacity to catch the salmon's attention - for a fly designed for lower levels of brightness. I shall need to take more trial shots in the lower light levels prevailing in September and October, which as you can see from the graph are about half those in August, and much better matched to the salmon's visual characteristics and the Dark Shrimp's design brief.
Depth 3'/1m Sun Out Direction - South Low oblique, range 6'/2m |
Depth 3'/1m Sun partial cloud Direction - South Oblique, range 4' 6"/1.5m |
Up in Window 2 (at midday), at a range of 1.5m the detectability and colour differentiation are good. I judge that the orange content is about right for the conditions.
2.5 lbs |
And here's a second opinion on that! Having set out to design a salmon fly, on this day at least, the Ure's sea trout found the large Dark Shrimp irresistible in bright conditions in broad daylight, and amidst a consistent hatch of sedges that they were taking on the surface. This was the first and smallest of the three that stayed on to come to hand. Its successors were 3 and 4 lbs respectively and nicely silver-grey, comprising a most pleasant but wholly unexpected reward in the absence of a salmon.
Conclusions
Overall I judge that the DS provides an excellent basis for further development. The key test will come in the duller days and lower sub-surface light levels of September and October, which framed the design brief that I gave to Darragh for tying the prototype. Even at this stage of development I shall fish the Dark Shrimp with some confidence.
Prototype 2 will involve an increase in the black component of the body and tail, and possibly a reduction in the silver banding to a narrower thread. The orange fore hackle and red head look perfect, so no changes there.
One other thing you may have noticed (or rather not) in the photos, is the near invisibility of the Seaguar fluorocarbon leader in almost every instance.
It's that time of year, I can't wait to get out again, but a very nostalgic trip to France for the commemoration of the 100th anniversary of the outbreak of the First World War and the Battle of Nery on 1st September will take precedence. Thereafter, with no Tomatin week this year, the Ure will feel the full force of my enthusiasm and energy. Anticipating your own enthusiasm, I wish you tight lines.
End of the day, job done, DS takes a breather in good company |
Comparator Photos
Blue Charm partial cloud distant |
Stoat's Tail in Window 2 strong sun |
Blue charm full cloud short range with shallow camera |
Stoat's Tail having crossed the Window 2-3 boundary short range ca 2'/60cm excess definition? |
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