Ultraviolet perception in trout
Numerous studies carried out across the Atlantic on brown trout and rainbow trout show the evolution of ultraviolet receptors along their growth.
During their first year of life, trout fry feed on zooplankton among other things. These micro-organisms absorb a large part of the ultraviolet light they receive and are therefore more easily spotted by a predator whose vision is sensitive to UV.
However, after the age of 3 years, the now adult trout lose the ultraviolet receptors and replace them with blue, green and red light receptors. The insects, fish and invertebrates that trout feed on do not have a high UV reflectance. Therefore, trout no longer need to identify and locate their prey via UV light.
How to adapt to these factors
A 3 year old trout measures, depending on the quality of its habitat, between 20 and 30 centimeters long. The use of ultraviolet reflecting lures when stalking large fish (over 40 cm), is therefore not beneficial to the angler.
On the contrary, if fishing tends to be complicated and individuals of sizes smaller than 25 cm would be enough to satisfy your fishing soul, UV reflecting lures will be a great asset to increase the visibility of your lure in the water and therefore your results.
Of course, there is no lure small enough to imitate zooplankton, but small individuals will react instinctively and may mistake your lure for potential prey.
When should you choose a UV reflecting lure over a standard lure?
It is normal to think that it is at solar noon that UV rays hit the earth with the most intensity, and this is the case.
However, the perception of UV by the eye of a trout will be more important at sunrise and sunset, when the wavelengths of light are shorter (meaning that ultraviolet and blue are present in greater proportion to green and red).
I recommend you try UV-reflective lures in low light, when you're targeting fish around 10 inches or smaller. If you're trying to lure a trophy fish, don't strain your brain picking a UV-reflective lure that the fish in question won't even be able to perceive.
