*edit. There's a mix use of UV and fluorescent colors in this article. Fluorescent colors are mostly used in flies and the effect visible to human eye. Thanks for the comments.
Most of time salmon anglers talk about fly colors or sizes. Sure, they are important but are there any tricks we might do with materials. UV -colors are definitely one.
Salmon has a fairly good eye sight. They see better different shades of green and blue when they enter the river and later on start seeing shades of orange. This is just due to the fact of their adaptation to their living environment. The blue-greenish shade of oceans apapts their eye sights into that environment.
The water color and the color of the surroundings reflect similar color objects in the water. Topher Browne does an excellent job in his book "Atlantic Salmon Magic" about the colors and reflections. Black is the only color that does not reflect light. Therefore it is a visible color in all water colors.
UV-materials have the magic effect of reflecting certain wavelength light not visible to human eye. How do the fish see it? It seems uncertain how they rely on UV light, but scientist have found out that some fish species use UV light to distinguish one species from another. It should be safe to say that UV materials are visible to fish as well.
We won't be able to get scientific proof ever of the battle over UV colored flies agains non-UV flies. But some occasional fly patterns rely heavily on UV materials used as strike points. I've slowly started switching to UV materials and can say that the catches have not decreased.
I encourage you to take a UV light and point it to your fly box. See which patterns stand out and take a closer look to see if they are the ones that have been producing fish. I would happily hear more of the results. Post your comments to our Facebook or Instagram page.
It's not often that salmon anglers are faced with high, warm water conditions in the latter part of the season.
I have experienced this twice now in Norway, and this situation is most common on rivers with a lake above their system that has a big enough catchment to collect localized rainfall, and or rivers that are fed via glacial melt water.