FLYMPH FORUM

Hi Mike,
I am surprised that my experience and what I've been taught varies greatly from what you say regarding brown trout. As a young man I spent time at our local fish hatchery in Carpenter's Brook hatchery in Onondaga County watching them rear brown trout for stocking in local creeks and streams. Fry kept in indoor troughs were given places to seek cover from the lights indoors. Also, hear is an excerpt from a book written by Cecil Heacox who was a trained fisheries biologist who actually worked in NY state hatcheries. Mr. Heacox was educated at Dartmouth, doing his postgraduate work at Cornell University. He worked his way up the chain from laborer to Junior Aquatic Biologist, Senior Aquatic Biologist, District Fisheries Manager, Secretary of the Department of New York State Conservation, and finally Deputy Commissioner of that department. I'm enclosing two pages from his wonderful book The Complete Brown Trout.







So, it appears brown trout do react to light, even as fingerlings, at least according to what I've seen at the hatchery and according to Mr. Heacox. How much UV light does artificial lights emit? I am not sure. I guess it depends upon the type of lighting used. The hatchery I looked in on regularly was lighted with standard, incandescent light bulbs. Daylight, of course, probably emits more, especially as the ozone decreases in our atmosphere.

Mark

Mark

If I am understand these things correctly, Sunlight consists of both rays within the visible spectrum and also UV which is not in the human visible spectrum.

It is well known that trout are adverse to strong sunlight. It is scientifically proposed that young trout have the ability to see both, the ability of adults to see the UV dimiishes. There is some research indicating that this ability may return at spawning time , as its a MAY and as spawning time does / should not be a time for us to fish then it has no relevance to us.

Your reference to the hatchery would correlate that juvenile trout shy a way from light, be that visible or UV is largely irrelevant to us. It is accepted that adult trout also shy away from bright light, if the scientific evidence that they cannot see UV is correct then we have to assume that they are shying away from light in the visible spectrum.

The trouts reaction to various light conditions is of more importance to us more from an actual fishing perspective than a fly tying perspective. To get down to the nitty gritty from a tying perspective it would seem to me that understanding how varying light conditions may impact on individual materials or combined materials and how it effects the illusion of us imitating specific trout prey.
It would seem to me that these are things worth time and energy investigating more than in things we cannot see or define , others may off course disagree with this.

Otter,
My take is that light, whatever wavelengths it is made up of is negative to trout and that may not JUST be UV light they respond to. Unless we can converse with the fish, itself, our theories, no matter how much they are investigated, remain theories unless there is specific scientific data that supports these theories to the Nth degree. Perhaps something in the trout's anatomy tells us something that help us determine the way trout respond to stimuli. Other than that, what we believe happens and the reasons we give for those circumstances may be nothing more than conjecture. As you said, we are very quick to judge results of new materials, and we often jump to conclusions based upon a few successes or failures regarding such things. I've said it before, and I'll say it, here, again. I often think we read way too much into trout behavior based on our own desires to categorize and pigeonhole results. We do the best we can on our assumptions and experience, and it is often the only means we have of making it work.

Digging into variables may, indeed, yield some insight into such things as we have been discussing, herein, but again these are observations based in human thought and supposition. Trout don't think as we do, and are often driven by stimulus- response rather than thinking- "Ah, that looks good. Think I'll eat that!" There are also many many variables that could determine what a response to a specific stimuli will be. How can we, who are not trout, determine how or why a trout reacts to that stimuli the way it does. We guess, surmise, theorize, postulate, etc., and at best we come up with a reasonable explanation enough to satisfy ourselves, when in reality we may be totally wrong.

Mark

I said I wouldn't post but the point of adding UVa type materials to your flies is because insects and baitfish relect UVa light. So to take the current point of UV light causing trout to be repulsed and applying that theory to objects exhibiting UV refraction seems illogical. Perhaps what I find most puzzling is the total rejection of of the UV premiss by some without any individual field study but secondhand references to others work ( mostly dated) that marginalizes the UV premiss.
I feel like Skues talking to Halford at the great wet fly vs. dry fly debate saying " but I have done it".

Mike

Thanks for the links. These posts of yours are exactly what I am talking about and what I use my black light for at home.

http://info.bluequillangler.com/blog/bi ... -Materials

I am most concerned with the fluorescent effect fishing for a spawning fish that for the most part is not eating to sustain itself- a sea run steelhead. Flies are not tied in most cases to mimic a natural food but are used to attract or irritate or evoke whatever it is in the nature of the fish to strike at the fly. I posit that hot spots on a trout fly change the nature of the fly from a natural match the hatch food item to an attractor. Sometimes it works other times it doesn't-just the nature of fishing. Sometimes curiosity kills the cat. Literature and experience of Steelhead fishers is replete with the success of fluorescent lures that mimic nothing in nature. Iridescence is another whole chapter open for discussion.

The second one you posted http://www.skiptonflytyers.co.uk/snippets.htm follows the report on UV Fluorescence at fishing depths with an article about the Tups Indispensable. Doesn't this highly touted rams wool fluoresce due to the urine? Many bleached and dyed materials will do the same including bucktails.

I agree with most of your posts and tie most of my flies along the same lines you do for trout as a natural food object and always for the visible spectrum. Thanks again for your words of wisdom and the depth of your discussion.

Soft-hackle wrote:Hi Mike,


So, it appears brown trout do react to light, even as fingerlings, at least according to what I've seen at the hatchery and according to Mr. Heacox. How much UV light does artificial lights emit? I am not sure. I guess it depends upon the type of lighting used. The hatchery I looked in on regularly was lighted with standard, incandescent light bulbs. Daylight, of course, probably emits more, especially as the ozone decreases in our atmosphere.

Mark

That is the same as my experience, trout fry both brown trout and sea-trout always seek cover, even from normal daylight or artificial lighting. However they will both flee very rapidly and panic if you shine UV light on them, sea-trout fry will panic if light falls on them at all. Just removing the tray covers causes them to panic, whereas brown trout fry do not seem unduly disturbed by it. If cover is available both will move into it.

Various types of artificial light produce no UV.

As far as I know the term "photo-tropic" is only applied to sessile organisms like plants; http://en.wikipedia.org/wiki/Phototropism it is usually defined as the "direction of growth towards light".

I have never heard it used in the context you used it before.

TL
MC

Roadkill wrote:Mike

Thanks for the links. These posts of yours are exactly what I am talking about and what I use my black light for at home.

http://info.bluequillangler.com/blog/bi ... -Materials

I am most concerned with the fluorescent effect fishing for a spawning fish that for the most part is not eating to sustain itself- a sea run steelhead. Flies are not tied in most cases to mimic a natural food but are used to attract or irritate or evoke whatever it is in the nature of the fish to strike at the fly. I posit that hot spots on a trout fly change the nature of the fly from a natural match the hatch food item to an attractor. Sometimes it works other times it doesn't-just the nature of fishing. Sometimes curiosity kills the cat. Literature and experience of Steelhead fishers is replete with the success of fluorescent lures that mimic nothing in nature. Iridescence is another whole chapter open for discussion.

The second one you posted http://www.skiptonflytyers.co.uk/snippets.htm follows the report on UV Fluorescence at fishing depths with an article about the Tups Indispensable. Doesn't this highly touted rams wool fluoresce due to the urine? Many bleached and dyed materials will do the same including bucktails.

I agree with most of your posts and tie most of my flies along the same lines you do for trout as a natural food object and always for the visible spectrum. Thanks again for your words of wisdom and the depth of your discussion.

It is entirely possible that the flies will work well for that, perhaps making the fish more aggressive? I really don't know.

Not all urine fluoresces. Some is visible in UV light with a special camera or similar, ( but does not fluoresce visibly in daylight/sunlight). To be perfectly accurate here one needs to refer to DFM ( Daylight Fluorescent Materials) as there are other types of fluorescence.

There are some mammals that use UV light, notably reindeer and rats;

http://www.bbc.co.uk/news/science-environment-13529152

http://www.ratbehavior.org/BlackLight.htm

Insects and birds can also see in UV light frequencies;

http://www.sas.upenn.edu/~ksundeen/spec ... tions.html

http://rosettastone.wordpress.com/2006/ ... otography/

http://www.naturfotograf.com/UV_flowers_list.html

TL
MC

Soft-hackle wrote:Otter,
My take is that light, whatever wavelengths it is made up of is negative to trout and that may not JUST be UV light they respond to. Unless we can converse with the fish, itself, our theories, no matter how much they are investigated, remain theories unless there is specific scientific data that supports these theories to the Nth degree. Perhaps something in the trout's anatomy tells us something that help us determine the way trout respond to stimuli. Other than that, what we believe happens and the reasons we give for those circumstances may be nothing more than conjecture. As you said, we are very quick to judge results of new materials, and we often jump to conclusions based upon a few successes or failures regarding such things. I've said it before, and I'll say it, here, again. I often think we read way too much into trout behavior based on our own desires to categorize and pigeonhole results. We do the best we can on our assumptions and experience, and it is often the only means we have of making it work.

Digging into variables may, indeed, yield some insight into such things as we have been discussing, herein, but again these are observations based in human thought and supposition. Trout don't think as we do, and are often driven by stimulus- response rather than thinking- "Ah, that looks good. Think I'll eat that!" There are also many many variables that could determine what a response to a specific stimuli will be. How can we, who are not trout, determine how or why a trout reacts to that stimuli the way it does. We guess, surmise, theorize, postulate, etc., and at best we come up with a reasonable explanation enough to satisfy ourselves, when in reality we may be totally wrong.

Mark

Mark I would probably agree with most of that - in theory Your take on the light issue I also agree with, with one provisio, that being that scientific research to date does postulate that adult trout cannot see UV light. Agreed, scientists are not always right.....

If as some would suggest, that their experience in using UV reflective materials as far as they are concerned is totally positive then that is their opinion. My experience is otherwise and that also is fair opinion. As you say , there are so many variables at play that both opinions are simply that, opinions. None the less, discussion, even argument on such things is educational amd that makes it worth while. One can learn a lot about many things in such discussion and I hope that is part of the reason we all partake.

Jim Slattery wrote:I said I wouldn't post but the point of adding UVa type materials to your flies is because insects and baitfish relect UVa light. So to take the current point of UV light causing trout to be repulsed and applying that theory to objects exhibiting UV refraction seems illogical. Perhaps what I find most puzzling is the total rejection of of the UV premiss by some without any individual field study but secondhand references to others work ( mostly dated) that marginalizes the UV premiss.
I feel like Skues talking to Halford at the great wet fly vs. dry fly debate saying " but I have done it".

Glad you have come back Jim.

If you have found that the use of UV reflective materials have greatly improved your flies then I will accept that - to argue would be plain silly and total nonsense on my part. As I posted above to Mark I have not found that such materials have benifitted my flies. As Hans would say , intended humour here, maybe your other flies were crap anyway and maybe mine couldnt be improved. or maybe I used the wrong UV materials in the wrong way, or maybe, or maybe , or maybe.....

However if the scientific evidence that adult trout do no see UV is correct then for the world of me (maybe I'm stupid ) I cannot fathom any correlation between " the point of adding UVa type materials to your flies is because insects and baitfish relect UVa light" when the scientific evidence suggests that trout cannot see it.

Whatever, I hope that we both continue to catch many trout for many years to come...

I hate to keep repeating this but it is the heart of the problem.

What colour is UV light? The answer is it has no colour. It is a radiation frequency. The various pictures you see taken in UV light are the result of technical tricks to make the frequencies visible. The "colours" used in such pictures are completely arbitrary.

See these examples and what the photographer has to say about it;

http://www.naturfotograf.com/UV_flowers_list.html

QUOTE
The UV range of the spectrum has no predefined colours, so we are free to assign any colour we like. There are no rules set in stone for this at all. I set out my UV work using film, so in principle would like the "film UV colours" (blue with UV absorbance often shown in reddish hues) to prevail. Different spectral response of the UV bandpass filters applied in these years, in conjunction with changing behaviour of the digital cameras and their RAW-file converters, have made this aim impossible to uphold. Thus, don't compare colours, compare patterns. I'm currently writing a tutorial on how the UV "colours" are created and how they should be interpreted, but for the time being, just enjoy the images like the pollinators enjoy their targeted flowers.
UNQUOTE

The only possible way to see if various materials might be useful in UV light, would be to take photos of the insects you want to represent in UV light, and then find a material with the same apparent characteristics. This also makes the assumption that trout can see such patterns. It is very very difficult indeed for a private individual to do this sort of thing on any scale and the requirements are horrendously expensive. There may be some flies that have certain patterns in UV light, and there may be materials which are similar. Unfortunately my data on this is extremely limited and I am not willing to publish any of it, it is mostly just surmise right now.

I am sorry if I appear extremely pedantic in regard to much of this, but there is no other sensible way to proceed. I would rather people consider me pedantic than be accused of producing bs, so I try to be as accurate as I possibly can.

TL
MC

Jim Slattery wrote:I said I wouldn't post but the point of adding UVa type materials to your flies is because insects and baitfish relect UVa light. So to take the current point of UV light causing trout to be repulsed and applying that theory to objects exhibiting UV refraction seems illogical. Perhaps what I find most puzzling is the total rejection of of the UV premiss by some without any individual field study but secondhand references to others work ( mostly dated) that marginalizes the UV premiss.
I feel like Skues talking to Halford at the great wet fly vs. dry fly debate saying " but I have done it".

HI Jim,

Nobody knows how most insects and baitfish appear in UVa or any other frequency of UV. There is very little data available on this.

Even assuming that trout can see in the UV spectrum, there is no way to know what they see in it, so how can you decide what to use and in what way on which flies?

I have not dismissed anything at all, Indeed I am currently in the process of investigating some plumage in this regard. This will only be of any use if I can find a correlation between the observed effects on the plumage, some insect, AND that this catches trout better than some other fly that does not have those materials.

Without knowing these relationships there is no sensible way to use any materials.

TL
MC