A reader by the name of Bryan recently inquired about Tenkara Guides’ article, “To UV or Not to UV”
. He wanted to know if there would be a follow up article on fluorescence in fly tying materials. I replied that, unfortunately, I was unable to find relevant peer reviewed scientific data directly related to the subject of fluorescence, iridescence, etc. on trout feeding behavior. This leaves us once again relying on the sage advice of other, more experienced anglers.
Within the week, we had our source of sage advice. Davy Wotton reached out to us, offering to share his knowledge on the subject. For those who are not familiar, Davy Wotton is an internationally recognized competitive fly fisherman, coach, and fly tier. He has authored a multitude of articles, books, and videos on various subjects related to angling, and has first-hand knowledge of the development of fluorescent fly tying materials. Ever notice Tenkara Guides’ fondness of the Davy Knot? Yep, same Davy.
Davy was kind enough to give me permission to share a letter outlining his thoughts on the subject. So, without further ado, here is some sage advice, straight from the desk of Davy Wotton:
This is a subject matter l have had great interest in since the 60s when at the time l started my professional fly fishing career as a pro fly tyer.
The use of material dyed with Fluorescent pigmentations goes back to the 40s. It was first marketed by John Ganter in the form of thread, flosses and nylon and was produced at the time for him by Dupont. There were 7 colors in the range known as DRF (depth ray fire). I still have some of the original material. Then a Scottish fly tyer by the name of Thoma Clegg produced the first publication related to the use of this material. Later in the UK a second material known as Daylight FL material came onto the market, it contained many different colors but none showed the intense color separations as the DRF range.
The above is a brief history of FL material coming into use for the fly fisherman.
What is confusing for the majority to understand is the use of the word UV, regardless if trout have or not the ability to detect UV, which so far as l am concerned is of no consequence when we are dealing with flies that incorporate materials dyed with FL pigments. For many reasons, the major one being that no food source trout see in the natural world exhibit afterglow emission’s of color related to the incidence of natural UV light sources. What we are simply dealing with is the fact that we use materials dyed with FL pigments that high color definitions.
The issues of iridescence as seen from the feathers of birds, wings of butterflies and beetles etc is a very different matter as this is a very different factor based on how light interacts with base color definition’s.
As you may know l was the developer and producer of the SLF range of dubbing materials since the 80s. l sold this business to Wapsi fly here in AR some years back who still produce the dubbings.
Briefly to obtain all the colors we use for fly tying material process we use both whitening agents and FL dye ware of different base colors blended. So for example if you subject your material to a black light or a UV light source you will see those treated with FL dye ware become exited which is the reason why they then fluoresce, all be it there is a great deal more to the physics as to why this is the case. You will see for example white materials such as hackle, marabou, white duck quills, deer hair that has been bleached fluoresce, which is not the case for the materials in a natural state most of which are a dirty and not fit for resale unless processed. This also the case for many other materials used, they are treated with FL dye to produce the end result.
OK, that said, there is no magic formula as such, all we are doing when we tye flies that incorporate FL material is differences in color definitions for the fly being tied. We know from fishing experience that certain flies that incorporate FL material may on the day be very effective, do l believe that this is related to the fact that some believe the trout has the ability to detect UV, no l do not, that’s BS in my book.
Having fished in more than 40 countries around the world, rivers, streams, creeks, natural and made made stillwaters way too many for me to remember the names of them all that there is no common factor related to the Salmonid species found, be they different strains of trout or salmon in so far as the use of flies that incorporate FL material. What l can say is that stocked trout do differ in feeding behavior and habit than those of true genetic strains born in the environment they habit. In other words stocked trout are easier to fool most of the time. By far wild brown trout by comparison are not.
Of course there are many other factors that are related to how well or otherwise FL material is viewed underwater such as relative angles of light, time of year, suspended matter, presence of plankton by percentage and so on, that being so the visual effects seen will differ which is also related to how well or otherwise fish of any species are able to visually see prey or food sources.
UV as such is simply a marketing strategy as most other fly tying products are, its not the rod, reel and line that matter all be it use of good equipment makes a difference. It is this Robert.
‘The catching of fish cannot be treated as a science.
Success is brought about by a level of understanding of the habits of the species and the relative skills of knowing how to pursue them, much of which is attained by past experience.’
How you choose to pursue the fish is by personal choice, fly fishers are no different to any other who chooses to angle with rod and line, all of which enjoy angling as a pleasure to pursue.
Best regards for now.