UV or not to UV

[flytire 0]

I have recently fished the UV2 product by Spirit River. It does produce more strikes at least it has for me. I was fishing docklights the other night you can see it under saltwater posts and the UV fly was producing strikes when the other was not.

 

do the dock lights provide ultra violet light? is uv light present in darkness?

 

i dont think humans can see the uv light. at least thats what ive read on multiple forums

[SilverCreek 0]

Confusion reigns.

 

 

I had a discussion with Reed Curry, the author of The New Scientific Angling: Trout and Ultraviolet Vision, about UV vision on:

 

http://www.theflyfishingforum.com/forums/coldwater-fly-fishing/301945-does-blue-excite-trout.html

 

There are differing opinions about whether adult trout can see UV. Reed presents some studies that show some UV cones persist into adulthood but it is unclear to me whether they are at the same density as in the parr. So it is unclear to me whether they see UV as well as young parr trout see UV. Secondly, these UV cones are on the dorsal retina (the upper surface) which sees the lower 1/2 of the visual field.

 

Other writings state that adult trout do not see UV.

 

http://www.troutu.com/class/color_vision_trout_eyes

 

http://www.sexyloops.com/articles/whatsalmonidssee.shtml

 

Let us assume that adult trout can see UV. Since we cannot see UV ourselves, we cannot tell by looking at a natural what frequency (color) of UV the natural reflects. Similarly, we cannot tell by looking at a dubbing or other tying material what UV color it reflects. Therefore there is no practical way to match the UV reflectance of a tying material with the UV appearance of the natural. For me, that is the weakness of any argument that says we should "match" UV, when there is no practical way to "match UV.

 

If we cannot match the actual UV reflectivity of a natural, and we use UV reflective materials; I believe it is like adding some visual attractant like the flash material to a pattern to attract the attention of a trout.

 

UV fluorescence is something different. Since the higher energy UV penetrates more deeply into water, UV fluorescent material can make a pattern more visible to the trout. Fluorescence is different from phosphorescent materials that glow in the dark and must be activate by UV light.

 

So when we mention UV materials, there are three types - Reflective, Fluorescent, and Phosphorescent. I leave it up to you to decide what materials should be used and how they should be used.

 

[SilverCreek 0]

Our "normal" color spectrum is that of an animal that is colorblind to UV. We can "imagine" the difference by comparing our "normal" spectrum with someone who is color blind to one of the colors (blue, green, red) that we can see.

 

Check the chart below. Note the normal vision at the top and the various types of color vision below. A color does not just drop out, the entire spectrum is different!

 

 

 

 

 

 

 

The difference is more apparent with a side to side comparison:

 

Deuteranopia = no Green receptors

Protopanopia = no Red receptors

Trinanopia = no Blue recpetors

 

 

 

 

 

Then there are combinations of the above:

 

 

 

 

 

 

We can then see by the examples of colorblindness above that a person that is colorblind would have a hard time matching the color of dubbing or tying materials to a natural. Similarly, we are colorblind to UV so how can we match the "color" of a natural to dubbing or tying material when we do not see UV. Our color wheel does not match the color wheel of an animal that sees UV. If an adult trout sees UV, I think we cannot just toss some UV material into a pattern and think it matches what the fish perceives.

 

 

 

http://farm3.staticflickr.com/2570/3842211138_ce69cbfab6.jpg

 

 

 

Since we cannot see UV below 380 nm, we are color blind to UV. Ask any person that is color blind. The absence of a single cone changes the entire color spectrum. They cannot match what they see to what we see. Similarly, we lack the UV cone and we cannot tell by looking at a UV dubbing if it will match what the fish sees.

 

 

[SCOwens 0]

The dock lights do not provide UV but I used the UV2 flies in a low light condition because that's what the UV2 is for. In a low light condition it would be more visible with tge UV2 fibers than without.

[SilverCreek 0]

The dock lights do not provide UV but I used the UV2 flies in a low light condition because that's what the UV2 is for. In a low light condition it would be more visible with tge UV2 fibers than without.

 

 

 

Can you explain how this is so.

 

Spirit River says their UV2 material fluoresce and reflect under UV light. They are not phosphorescent. IF there is no UV, they cannot fluoresce or reflect. Phosphorescent UV material absorb UV light and then give of a glow over time. But Spirit River does not mention phosphorescence.

 

http://spiritriver.net/uv

 

Reflectance of UV is pretty simple and straight forward. Basically material reflect or absorb radiation which is what light is. Mirrors reflect so these material act as mirrors and reflect back UV. In fact, you do NOT need special UV reflectant materials to reflect UV. Flash mirror like materials reflect UV and so the silver mirror like tinsel or Flashabou material we've been using for years reflect UV light.

 

There is confusion between UV fluorescence and UV phosphorescence.

 

Both are due to the electron of the atoms of the material absorbing the light photons and and putting the electrons in to a higher energy state (orbit). Then when the electron drops back to the lower energy state, the energy is released as another photon of slightly lower energy. This means the lower energy photon is now of a longer wavelength and lower energy than the original UV light and is now visible light.

 

In fluorescence, the material releases the energy immediately. In phosphorescence, there is a delay in release of the light photos so the material continues to flow after the UV light is shut off. In the absence of UV, there can be neither fluorescence or phosphorescence.

 

If a material is phosphorescent, we could shine a UV flashlight on the fly, and it would continue to glow after we cast it. Spirit River materials are NOT phosphorescent so how can there be any effect if there is no UV in the low light you are fishing in?

 

Remember that sunsets are red/orange. That is because the red end of the spectrum is scattered around the horizon from the part of the sun that has already under the horizon. The UV is absorbed because it has to go through more atmosphere and it is not reflected around the horizon. So sunsets have relatively LESS of the blue and UV light compared to full sunlight.

 

http://en.wikipedia.org/wiki/Sunset

 

http://nodivisions.com/blog/2011/06/03/Why_You_Cant_Get_Sunburn_Near_Sunrise_And_Sunset

 

http://en.wikipedia.org/wiki/Fluorescence

 

http://en.wikipedia.org/wiki/Phosphorescence

[overmywaders 0]

I have never found any peacock eyes that are more than a few percent UV reflective. Nor have I have discovered any iridescent feathers that are UV reflective. Since the UV reflection is a factor of the construction of the feather, not a matter of pigmentation, in natural feathers, it would seem that iridescence and UV reflectance are antithetical. The popular and effective flies that use peacock herl - Coachman, Royal Coachman, Prince Nymph, Zug Bug, etc. - also have a highly UV reflective patch of duck feather, turkey biot, or natural white bucktail (Note: some white feathers and hairs are treated with TiO2 to make them appear a brighter white; this reduces their UV reflectance markedly).

 

As Silver is aware, the majority of the fishery biologists studying trout vision have concluded that mature trout either do not lose all their UV-specific cones or regrow some. What is also true is that there is a secondary peak for each of the red, green, and blue cones in the trout's retina, and that peak is in the UV... so all of the cones register UVA wavelengths. Of equal interest is the fact that the rods of the trout retina, which are used for night vision, are more sensitive to UV light than blue light. The UV percentage of solar light increases at dusk, the mayflies navigate by UV vision and find their mate based upon UV markings, so it is not unreasonable to approximate such UV markings when fishing mayfly patterns at night.

 

Humans start with UV vision, but lose it as the lens of the eye accumulates yellow pigments which block the harmful UV. Those people who have a clear lens or have their lenses removed in cataract surgery, can see in the UV -- the artist Monet is one example. Trout don't need protection from UV because they have stem cells in their retina capable of regrowing cones.

 

We already use many natural UV reflective materials in our flies. Most of us need not look for more materials. In my book I detail the UV aspects of twenty-four of the most popular (hence, I hope, effective) dry flies of 1980. In each case, the use of UV reflective material is in proportion to the naturals represented. For example, the common cricket reflects very little UV and the popular artificial cricket also reflects little.

 

Best regards,

Reed

[Piker20 0]

Very interesting Reed.

whats the book title

[overmywaders 0]

Piker,

The book is http://www.amazon.com/New-Scientific-Angling-Ultraviolet-Vision/dp/0984086307/

 

regards,

Reed

[cheech 0]

I have never found any peacock eyes that are more than a few percent UV reflective. Nor have I have discovered any iridescent feathers that are UV reflective. Since the UV reflection is a factor of the construction of the feather, not a matter of pigmentation, in natural feathers, it would seem that iridescence and UV reflectance are antithetical. The popular and effective flies that use peacock herl - Coachman, Royal Coachman, Prince Nymph, Zug Bug, etc. - also have a highly UV reflective patch of duck feather, turkey biot, or natural white bucktail (Note: some white feathers and hairs are treated with TiO2 to make them appear a brighter white; this reduces their UV reflectance markedly).

 

As Silver is aware, the majority of the fishery biologists studying trout vision have concluded that mature trout either do not lose all their UV-specific cones or regrow some. What is also true is that there is a secondary peak for each of the red, green, and blue cones in the trout's retina, and that peak is in the UV... so all of the cones register UVA wavelengths. Of equal interest is the fact that the rods of the trout retina, which are used for night vision, are more sensitive to UV light than blue light. The UV percentage of solar light increases at dusk, the mayflies navigate by UV vision and find their mate based upon UV markings, so it is not unreasonable to approximate such UV markings when fishing mayfly patterns at night.

 

Humans start with UV vision, but lose it as the lens of the eye accumulates yellow pigments which block the harmful UV. Those people who have a clear lens or have their lenses removed in cataract surgery, can see in the UV -- the artist Monet is one example. Trout don't need protection from UV because they have stem cells in their retina capable of regrowing cones.

 

We already use many natural UV reflective materials in our flies. Most of us need not look for more materials. In my book I detail the UV aspects of twenty-four of the most popular (hence, I hope, effective) dry flies of 1980. In each case, the use of UV reflective material is in proportion to the naturals represented. For example, the common cricket reflects very little UV and the popular artificial cricket also reflects little.

 

Best regards,

Reed

that... just.... happened.

 

Reed, We are big fans of your work at www.flyfishfood.com, and have constructed many patterns based on your findings. = flyfishing and flytying gold. Keep up the great work!

[overmywaders 0]

Cheech,

 

Thanks for the kind words.

 

Best regards,

Reed

[Davidpensfan87 0]

In my opinion, it all depends on the situation. I usually use non uv and uv. I think uv is just an added tool in the anglers' arsenal and should not be the only type of material used. Using only uv or non uv just because you think one always works better than the other is like using only one color or one size of a fly instead of different colors or different sizes, but hey, if that's how you want to fish, that's your prerogative, and I have no right to tell you how to fish. Also keep in mind that uv products were almost unheard of a year or so ago, but I was still catching fish like crazy a year or so ago.

[overmywaders 0]

Actually, UV reflective fly tying materials are as old as fly tying. Think of how many patterns among the "Catskill style" dries use wings of pintail, wood duck, or teal white and black striped breast and flank feathers. Wings of these feathers show bright and dark in the UV; just as the markings on mayfly wings in the UV. One of the most popular flies -- the Adams -- also has very bright and varied wings in the UV.

 

Adams in visible light

 

Adams in reflected UV

 

Just like the other wavelengths we can't see, ultraviolet is operative in our fly tying whether we know it or not.

Good fishing.

 

Regards,

Reed

[Piker20 0]

I ordered the book and look forward to seeing it. I've always liked black and white for the broken contrast it gives a fly but that photo shows there is an invisible property to that colour. I take it dying black and white with another colour negates the UV benefit?

[netabrookie 0]

This is all very interesting fellows. I recently came across an older book by Skues and was reading his thoughts on the colors that a trout might see or not and after almost a century some of his thoughts are still fairly accurate.

[Piker20 0]

Well Reed your book arrived. Very interesting. I was most concerned with the photo of the fishing waistcoat under UV. What solutions to the clothing have you been able to find?? Does the same apply to tan waders???