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Old 11-25-2012, 03:52 PM
silver creek silver creek is offline
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Default Re: Does blue excite the trout?

Thanks for your reply.

Regarding perception and sight, you quoted Inigo Flamarique who "believes that trout lose all but a small percentage of their UV-specific cones at smoltification" and therefore "MAIN SENSORS OF THE UV LIGHT WILL NOW BE THE BLUE CONES".

You will recall that I discussed earlier that UV light stimulating a receptor other than a UV receptor is not perceived as UV by the fish. In this case, the stimulation of blue receptor will be perceived by the fish as blue, which is different than the trout's perception of UV via UV receptors. And I also pointed out that this is so, whether the UV receptors are active or not. The presence or absence of UV receptors has no bearing on the activity and stimulation of the blue receptors; and therefore, the fish sees the same degree of blue from the reflected UV regardless of the activity of the UV receptor. So as the UV receptors are diminished, the amount of blue stimulation does not change. The corrolary would be that the UV color seen by the fish diminishes as the UV receptors diminish, but the UV perceived as blue, green, red do not.

If the main stimulus of UV in the adult trout is indeed the blue receptor as the researcher you quoted states, then does not the trout "perceive" the UV as mainly blue? It seems to me that the conclusion follows from the inference, and the inference was from the researcher you quoted. If not why not?

Why does not the conclusion that the fish perceive blue as the main color of UV stimulus follow from "MAIN SENSORS OF THE UV LIGHT WILL NOW BE THE BLUE CONES"?

We seem to be plowing the same ground but at cross purposes to each other. I do not understand where "sight" and "perception" deviate in this case. Are you saying that UV light is not seen mainly as blue in adult trout? If that is so, how can the statement of Inigo Flamarique be true?

Addendum:

After reading some more, I find references that instead of receding, the UV receptors turn into blue receptors.

Cheng, C. L. & Flamarique, I. N. (2007). Chromatic organization of cone photoreceptors in the retina of rainbow trout: single cones irreversibly switch from UV (SWS1) to blue (SWS2) light sensitive opsin during natural development. Journal of Experimental Biology, 210, 4123-4135.

Reed, is this what occurs and is the information I am lacking ? If so then the addition of blue receptors would increase the perception of blue.
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Regards,

Silver



"Discovery consists of seeing what everybody has seen and thinking what nobody has thought"..........Szent-Gyorgy

Last edited by silver creek; 11-25-2012 at 04:30 PM.
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