Still looking and trying to decide on a "blacklight" for night fishing!
For Reference, blacklight has a wavelength of 400 nm or less. By contrast, the quote..quote black light LED fishing lights, UV lights, emit a wavelength of 405 nm, while the quote..quote, blue lights emit a wavelength of 470 nm. So what is the answer?
Quoting:
How are fish adapted to the optical properties of water?
Water not only reduces the amount of light that penetrates a fish's world but also the kind of light. The extinction of sunlight in the water column happens very fast. On average, 90% of the light is gone by 10m depth, and 99% by 40m. Varying wavelengths of light are absorbed at different depths. UV light is eliminated in the first few millimeters of water; infrared in the first few centimeters. Of the wavelengths of visible light, the red wavelengths disappear in the first 5m or so, then the yellows. Eventually, at a depth of around 100m, all that remains is a narrow band of blue-green wavelengths (510nm-540nm).
There is complete darkness below about 200 meters. It makes good sense that fish eyes have maximum sensitivity for blue light (at about 520nm wavelength).
Fish visual pigments, called rhodopsins, are photosensitive protein pigments found in the rod cells of the retina. When light passes into the eye and reaches the retina, rhodopsin protein molecules become photo-excited. Biochemical changes in the structure of the molecule cause electrical impulses to run down the optic nerve sending information to the brain.
Rhodopsins, which are also found in all other vertebrate animals, are a dark reddish color. Like deep growing red algae, the rhodopsin pigment absorb the only wavelengths that penetrate the water column: greens and blues. Therefore, the rhodopsin, like the algae, reflects the light it does not absorb — which is generally the red wavelengths of light, causing its reddish color. Our own human rhodopsins are still red, a heirloom of our aquatic ancestry.
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