The Color Orange

[overmywaders]

Deja vu all over again.

Otter, you speak of what you know not. I mention quite clearly, with illustrations, the need to assume a combination of R, G, B, and UV. Why don't you borrow the book from the library, or steal it from someone, whichever fits your style. I'd say borrow it from a friend, but that brings up an extremely remote possibility.

Then, having read it, you can tell me what premises I am putting forward and dispute them properly. Otherwise, you are criticizing without a context. As before, I am not intent on writing the book a second time online.

Regards,
Reed

If anyone is really interested in how aphakic humans see, here is an interesting source - http://neuronresearch.net/vision/files/tetrachromat.htm Imagine then the scotopic, photopic, and mesopic vision of trout, which begin life depending on UV for their food.

[Otter]

I'd say borrow it from a friend, but that brings up an extremely remote possibility.

Potentially insulting, but very witty

Thank you for the link, I shall educate myself further.

[Otter]

Reed, as Shakespeare said in Hamlet , " There are more things in heaven and Earth....." - so I travel a road of learning a little of the world of light and colour. Fishing , UV etc.. aside, it certainly is a fascinating subject and one I am glad you have brought to this forum.

Since Scotopic is the first on the list thats where I started http://www.fs.fed.us/rm/boise/AWAE/scie ... err00x.pdf

A very interesting part of this document - of course I cannot say if this is true or not or whether it has any relevance to your discussion on " UV dominates visible light in low light conditions"

Perhaps you would care to discuss the content of this except as it would appear to contradict your views.
Off course I appreciate that other studies may well contradict this - i do note he states personal observation - and not knowing what was the limits etc of this observation were. No doubt you probably have more accurate knowledge on this.

Off course I need to follow on into the photopic, and mesopic topics. Fascinating stuff, thanks for sending me down this road of enlightenmen - very enjoyable even if i do not understand the half of it.


"This range from blue (400 nm) to deep red (720 nm) was
appropriate for this study because trout cannot
see infrared radiation (approximately >720 nm)
and because there is very little light <400 nm
(UV) in the natural environment during twilight
or at night after the sun has dropped below
the horizon (e.g., Williamson 1995, Rader personal
observation). This is also the range of light
most available at twilight and at night and is
thus the most important range in dim-light
studies."

[Otter]

this is also very interesting - could it possibly explain why juvenile trout use UV sensitivity - and in their case why UV could dominate visible light - just a thought.

We selected fish of each species within
the same size range (25–30 cm) because the
number of visual receptors (rods and cones)
and the concentration of scotopic pigments
(rhodopsin and porphyropsin) increase as trout
grow, making larger fish more sensitive to dim
light than smaller fish (e.g., Allen et al. 1982).

[overmywaders]

Otter,

I assume by now you have at least searched for a means to read my book. Don't tell me how, I don't wish to appear complicit; I'll watch the newspaper headlines for mysterious nocturnal events.

Had you done so, you would have noted the following cites:

[44]“Interestingly, ambient light at dawn and dusk
contains a particularly high proportion of short
wavelengths.”
Bat Eyes Have Ultraviolet-Sensitive Cone Photoreceptors
Müller B, Glösmann M, Peichl L, Knop GC, Hagemann
C, et al. 2009
PLoS ONE 4(7): e6390. doi:10.1371/journal.
pone.0006390
[45] “The second experiment investigated more specifically whether UV cues are especially important in
dawn and dusk when short wavelengths are high in the proportion of available light.”
Do house mice use UV cues when foraging?
Johanna Honkavaara, Helena Åberg and Jussi Viitala
Journal of Ethology
Volume 26, Number 3 / September, 2008

Of course, if you want something specifically trout related you would read "Is the Use of Underwater Polarized Light by Fish
Restricted to Crepuscular Time Periods?"
INIGO NOVALES FLAMARIQUE*~, CRAIG W. HAWRYSHYN*
Recewed25 September1995;m revisedform 21March1996;mfinalform 2 July 1996

Excellent work. In it you find the following:

As may be inferred by the dispersion and absorption
coefficients of light, wavelengths that penetrate most
through the media are also the least polarized (%
polarization increases with increasing absorption and
decreasing dispersion; Timofeeva, 1961). Accordingly,
middle wavelength light, which penetrates most in the
waters examined, exhibits the lowest degree of polarization,
while UV and short wavelengths show the highest
percentages (Fig. 9). During the day the highest %
polarizations could reach 35’%, while during crepuscular
periods these values were significantly higher (Fig. 7
legend). These increases during dawn and dusk and the
spectral changes observed are due primarily to enhanced
scattering but also to airglow phenomena. Indeed, the
crepuscular (or twilight) sky is characterized by electronic
transitions of atoms and molecules resulting in
emission bands at various visible wavelengths (Craig,
1965).Oxygen atoms emit a dual “line” in the red part of
the spectrum at 630 and 636.4 nm, contributing to the
observed “red” sunsets. However, the strongest emission
bands are the product of N2+ transitions and occur in the
UV-A (A= 391.4 nm) and in the blue (1= 427.8 nm)
parts of the spectrum (Craig, 1965),which would explain
the shifts towards shorter wavelengths during twilight.

…

Visual responses of rainbow trout under natural light
settings
Although the model fit was not always very accurate
(possibly due to inaccuracy of the polynomial template,
especially in the P band absorbing regions), the fits show
a progression of increased activation of the UV cone
mechanism towards crepuscular periods for the ON
response pathway (Fig. 13, Table 3). During bright light
conditions[Fig. 13(A)],the ON response is dominated by
the short and long wavelength mechanisms, with a
prominent OFF response in the middle to long wavelengths.
The OFF response is dominated by the middle
Wavelength mechanism under moderate Iight levels [Fig.
13(B)],but the ON-response is now a combination of all
the cone mechanisms. In particular, the UV peak starts
being noticeable and a middle wavelength mechanism is
also present. As the levels of background light diminish
towards the crepuscular condition, only the UV and long
wavelength mechanisms are major components of the
ON response [Fig. 13(C)]. The OFF response is still
dominated by middle wavelength mechanism input, but a
smaller contribution now arises from the long wavelength
mechanism.

I think this illustration from the same paper might also illuminate you:


Note the trout's response during the crepuscular period (dawn and dusk).
Regards,
Reed

[overmywaders]

Summary of previous post:

I don't blame anyone who finds the technical details of my previous post burdensome and boring. Not all scientists can do standup, and those two aren't among the few.

However, in summary, what the scientists - specifically trout vision specialists - are telling us is that rainbow trout; whether or not they have specialized UV cones left at maturity, send signals over the optic nerve in recognition of UV light. They also are indicating, in both text and graphs, that the trout are sending those signals in moderate amounts at midday, mixed with signals from other wavelengths. In the evening the amount of UV signals increases dramatically. And at dusk the UV signals clearly are the primary signals in volume, far greater than the red bands of light.

They also state clearly that the percentage of available light at dusk and dawn is weighted in favor of UV.

Dr. Craig W. Hawryshyn has assured me that he stands behind the science in my book and thanked me for writing about a subject so dear to him. Dr. Inigo Novales Flamarique had a falling out with Craig a few years ago and has since adamantly opposed the view that trout retain UV specific cones after smoltification. He is a lone voice in this. However, Inigo has assured me in writing that even if the UV-specific cones are lost, the research regarding a mature trout's use of UV light - such as we see above - is solid, because the UV signal processing is there and the other cones (and some also say rods) take over the function.

I hope this is the end of this discussion. I thought, while writing the book, that people would appreciate the numerous citations I provided. Little did I know that I would need to go through my archives of scientific papers for additional citations - largely because some people will quibble with my work, though they haven't even read it.

Regards,
Reed

[hankaye]

overmywaders, Howdy;

I hope this is the end of this discussion. I thought, while writing the book, that people would appreciate the numerous citations I provided. Little did I know that I would need to go through my archives of scientific papers for additional citations - largely because some people will quibble with my work, though they haven't even read it.

Regards,
Reed

Don't think they are disagreeing with your work (by that I take it you meant your book), I believe they were disagreeing with what you were saying on the forum.
The 2 are not the same. Although some of the content of your book was quoted. Parts are parts not, in my opinion, not as succinct as the whole. Sometimes it becomes contextual. The paragraph in front or behind may be what throws the switch to light the light..... who knows ??? As with a large meal, when there is a large amount of information that is unfamiliar it requires an extra amount of time to be digested (processed I believe is the newer term).


hank

[JohnP]

All this stuff makes my head hurt. Makes me want to go fishing.

[DUBBN]

All this stuff makes my head hurt. Makes me want to go fishing.

[overmywaders]

I want to go fishing, too. We've had some much-needed rain and the rivers are coming to a nice level.
I think I will tie some Partridge and Orange as well as some Mock Snipe and Purple this weekend (I have no snipe, despite endless hunting).
Yes, that sounds very, very good.

Have a good weekend,
Reed