Troutnut.com Fly Fishing for Trout Home
User Password
or register.
Scientific name search:

> > UV spectrum and trout, Page 2



Post Reply
Page:1234
EntomanMarch 14th, 2013, 2:38 pm
Northern CA & ID

Posts: 2604
Over time I've come to consider color to be one of the least important variables in fishing presentation in general

With notable exceptions, I've come to largely the same conclusion, Paul. I don't know the proper definition, but to me what seems more important than the color is the amount of light reflected regardless of color (how it would be perceived in a black & white photo). I think the reason some of our flies work that are apparently the wrong color is for this reason. For example, some tannish or grayish dubbings look much closer to the naturals (in gray scale) than some of the dubbings we use that are a much closer match color-wise.

Back to fluorescence - is it all that important in flies if they are fished too deep for low frequency UV to penetrate? I've often wondered about it with steelhead flies. Most patterns with in these colors are fished in the prime low light of dawn & dusk and the materials have low amounts of phosphors (won't glow in the dark from charging).
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
MartinlfMarch 14th, 2013, 6:39 pm
Moderator
Palmyra PA

Posts: 3233		Interesting comments, all. Thanks.
"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell
EntomanMarch 14th, 2013, 7:39 pm
Northern CA & ID

Posts: 2604
...I've noticed that some favorite dubbings fluoresce under black light, and linking that fact with the photos of scorpions under black lights I've wondered the same thing that he did: is this quality a trigger?

Or perhaps the opposite in some cases, Louis. This may be tied in with the mystery mentioned in my previous post. Your idea to test brighter olives, sulfurs, and reddish browns before incorporating them in our flies is a heck of an idea!
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
CrepuscularMarch 14th, 2013, 8:38 pm
Boiling Springs, PA

Posts: 923		Excellent thread people! I wonder if I can get any mayflies to glow like those scorpions do?
MartinlfMarch 14th, 2013, 8:54 pm
Moderator
Palmyra PA

Posts: 3233		Eric, have you done any sampling near Three Mile Island?
"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell
CrepuscularMarch 14th, 2013, 9:38 pm
Boiling Springs, PA

Posts: 923		Yes, that's where I collected this one http://www.troutnut.com/specimen/1025

But seriously, I wonder what happens when you put the uv light on some of them?
MartinlfMarch 14th, 2013, 10:27 pm
Moderator
Palmyra PA

Posts: 3233		Me too.
"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell
EntomanMarch 14th, 2013, 11:34 pm
Northern CA & ID

Posts: 2604		I've used black light to collect critters before and never noticed any of them glowing.
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
CrepuscularMarch 15th, 2013, 9:00 am
Boiling Springs, PA

Posts: 923		yes me too, I was thinking more of immatures.
PaulRobertsMarch 15th, 2013, 11:13 am
Colorado

Posts: 1776		I'm going OT. But this is pretty cool...

During a small mammal survey for a mammalogy class we put Peromyscus mice into a bag of fine UV dust, gave em a shake, then released them at night. Gave them a half hour and then tracked them with a black light. Their footsteps fluoresced and we got to see how two look alike species, P. leucopus and P. maniculatus, partitioned habitat. P maniculatus is terrestrial and its tracks followed the edges of logs and fallen branches on the forest floor and disappeared into a rotted stump. P. leucopus is aboreal and it ran on top of the logs and fallen branches. It then ran straight up a tree and disappeared in a small hole way up there. Pretty cool to see.
MartinlfMarch 15th, 2013, 1:17 pm
Moderator
Palmyra PA

Posts: 3233		Yes, way cool, Paul. Thanks for that story. But back to fluorescence and fish. A now defunct shop, Cold Spring Angler, used to sell fluorescent orange dubbing to tie an ant pattern. Eric do you have some of it? I've had exceptional luck with these ants, sometimes when nothing else would work. Comments above lead me to doubt that any ants fluoresce, though I hope to do some checking in the future, so my guess is that the fish are responding to something odd that just "might" taste good, much the way they probably respond to fluorescent strike indicators. The same might go for Creno's purple hare's ear that fluoresced, and caught so many fish. Anyway, I'll continue to use such dubbings, and perhaps mix up a few others to try, checking with my black light. And let's not forget those hot spots on flies that have become so popular. I've had some luck with them too.

OK, why didn't I do this before? Now I understand Eric's comment on immature stages. Internet searches turned up this:

http://www.hindawi.com/journals/psyche/2011/875250/

http://pubs.acs.org/doi/abs/10.1021/jf020775m
"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell
EntomanMarch 15th, 2013, 5:35 pm
Northern CA & ID

Posts: 2604		Interesting papers, Louis. I noticed to pick up the fluorescence though the researcher had to both amplify it with photo techniques as well as black light to "charge" the samples. He also soaked the critters in alkaline compounds w/ alcohol to expose the special phosphorizing proteins in the unsclerotized sutures. The chitinous cuticles did not fluoresce. Couple the lack of these enhancements with the depth of water that imatures live in and I doubt that fluorescence is a factor. Low frequency UV doesn't penetrate very well except in very clear and still water. Even our clearest spring creeks look pretty turbid when you go under the surface (this never ceases to amaze me). It's a different matter for flies near the surface like your ant pattern or my halo pupa. The same thing for steelhead flies that are fished high in the water column as well, I suppose.
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
EntomanMarch 15th, 2013, 7:30 pm
Northern CA & ID

Posts: 2604		Something that got lost in the discussion is "black." How do fish see it? There may not be enough phosphors and charging UV to make critters fluoresce much light in the visible spectrum, but what about black looking nymphs reflecting the small amounts of UV available? In other words is what looks black to us really black? Paul mentioned that he remembers research showing that adult trout don't have the ability to perceive UV, so the discussion may be moot, but any thoughts?
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
MartinlfMarch 15th, 2013, 9:15 pm
Moderator
Palmyra PA

Posts: 3233		That's a whole other kettle of fish; I'll have to think about it a bit. But good points.
"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell
OvermywaderMarch 26th, 2013, 11:56 am
Posts: 31I thought I might enter this discussion to clear up a few issues regarding ultraviolet light.

The near ultraviolet (wavelengths from 320nm to 400nm, a.k.a., UVA) can penetrate water up to 600 meters deep. The reason divers wear fluorescent patches is because the UV causes the patches to fluoresce, long past the depth of visible light.

Phosphorescence is the ability of a material to emit light over a period of time. Fluorescence is when photons of light (usually UV wavelengths) are shifted to a longer wavelength and immediately emitted - usually as a visible light.

Diffuse reflection (as compared to shiny, mirror-like specular reflection) of UV light is how many animals identify each other. For example, all tested families of birds see in the UV (as well as RGB). Typically, male birds will have "honesty markings" which are only visible in the UV. As the bird ages, the honesty markings fade and the female knows that, although identical in visible light to a younger bird, this one is an old fart and not worth her time -- even if he buys the drinks. :)

Here is an example of GP crest in visible light. They appear identical -


and the same thing in reflected UV



notice how much brighter the crest on the left is than the other in the UV?

Regarding whether trout see in the UV. They lose most, but not all of the UV specific cones during the smolt stage. However, all of their cones have a secondary peak in the UV, so as the percentage of UV increases at dusk, the UV vision begins to predominate. At night, the rods of the retina are used and these are actually more sensitive to UV than to visible light.

Why worry about it? One reason is that mayflies use UV vision at night to identify their mates by species and gender using UV specific markings. When you only have one night of love, it seems worthwhile to spend it with the right species. :) Trout are going to see these markings. If your Adams has them, but your buddy's doesn't, who will be likely to get a confident rise?

Just some thoughts.
Regards,
Reed

Overmywaders
CrepuscularMarch 26th, 2013, 12:46 pm
Boiling Springs, PA

Posts: 923		Thanks for posting Reed!
MartinlfMarch 26th, 2013, 1:55 pm
Moderator
Palmyra PA

Posts: 3233		Yes! Thorough and detailed analysis of pertinent issues; clearly and wittily stated.
"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell
OvermywaderMarch 26th, 2013, 8:38 pm
Posts: 31I forgot to address the question: "What about black?"

In water carrying a lot of silt or other fine particles, UV is scattered by the particles, creating a (UV) light background for anything dark. The same is true to some degree after dark. This is one reason why black wet flies, that is flies which reflect little UV, are effective at night and when the water is turbid -- the UV-dark fly stands out well against the ambient UV background.

Regards,
Reed

Overmywaders
EntomanMarch 26th, 2013, 8:46 pm
Northern CA & ID

Posts: 2604		Welcome to the forum, Reed! Thanks for the great info. I'm still having trouble grasping the concept of reflected UV being made visible by artifice. Also my understanding is not all black is black, right? Wouldn't a black (or any color for that matter) that reflects UV look the same to us as the black that doesn't?
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
OvermywaderMarch 26th, 2013, 9:13 pm
Posts: 31Yes, the black that reflects UV would indeed look the same in visible light as black that doesn't. So, too, with any other color.

Most natural white and light gray feathers reflect a high percentage of UV. However, if the bird had them as honesty markings, and the bird was old when the feathers were removed, they might not be very UV reflective. Also, some companies treat white feathers to make them look whiter; this can result in actually reducing the UV reflectivity by obscuring the feather with UV absorbing pigments like TiO2.

For example, the white hackles shown below in visible light. The center batch looks a bit scruffy. It was washed and bleached, but not "whitened".


Now the same hackles in reflected UV -


White marabou is also often a victim of this whitening. One angler showed me two white marabou streamers he had tied from two different batches of marabou. The same shocking contrast as seen above.

Regards,
Reed

Overmywaders
Page:1234

Quick Reply

You have to be logged in to post on the forum. It's this easy:
Username:          Email:

Password:    Confirm Password:

I am at least 13 years old and agree to the rules.

Related Discussions

TitleRepliesLast Reply
Re: ampflies
In Fly Tying by Bowmandjk		1Jun 14, 2007
by Shawnny3
Re: Another sulphur for comment
In Female Ephemerella invaria Mayfly Dun by Martinlf		1Aug 21, 2007
by Gene
Re: Time for a Magnifier Lamp?
In Fly Tying by John888		4Nov 8, 2015
by John888
Re: Unidentified Mayfly
In the Identify This! Board by And		7Jun 19, 2008
by And
Re: Unidentified Mayfly Kansas City, MO
In the Identify This! Board by Pdcox		4Apr 16, 2020
by Taxon
Re: LAKE KHOBI (GEORGIA)
In General Discussion by Kinalia		4Jan 7, 2013
by Mcjames
Re: Chimarra
In Theliopsyche Little Brown Sedge Adult by Taxon		11Dec 31, 2007
by Taxon
Re: 62 classic wet fly patterns
In Fly Tying by Iasgair		1Oct 26, 2018
by PABrownie
BWO
In Male Attenella attenuata Mayfly Dun by Oldredbarn		0
Re: UV Tying Materials - does this really make sense ?
In Fly Tying by GearTheory		30Jan 13, 2015
by Captaincon