Nature is full of little curiosities that never cease to amaze the observers and the enthusiasts of life. At the Gouin reservoir, walleye with a bluish coloration are one of those curiosities which has certainly attracted the eye of fishermen but also the attention of scientists.
The presence of a bluish coloration on the surface of the skin is a phenomenon known in North America with walleye. Science has been able to demonstrate that this coloration is the result of the expression of a protein, sandercyanin, present in abundance in the mucus which covers the skin surface of the walleye. This protein is expressed more in environments where the oxygen concentration is low and the temperature of the water colder.
But what is the mechanism explaining that in a given lake, for example the Gouin reservoir, we find both yellow walleye of typical coloring and yellow walleye of blue coloring?
Two different species of walleye?
First seen in the Great Lakes, blue walleye was classified by scientists as a species of its own right because of different morphological characteristics and lifestyle habits of walleye. Due to overfishing in the Great Lakes, yellow walleye with blue coloring is now absent. Nevertheless, with technological advances in science, we now know that yellow walleye and blue walleye are one and the same species
Some clues …
A study conducted by a Quebec researcher, Yves Paradis, on several Canadian shield lakes located around the Gouin reservoir, yielded interesting clues to better understand the phenomenon (Paradis and Magnan, 2005).
A somewhat different morphology ...
The blue-colored walleye would have a more elongated muzzle in the lakes of the Canadian shield and a somewhat different dentition in the canines. Similar morphological differences were also observed among Great Lakes walleye populations.
The habitat ...
The literature reports that blue walleye would prefer the deeper areas of lakes, where the temperature of the water is colder and the oxygen rarer. This preference for habitat has an impact on the growth of blue walleye. Research has shown that blue walleye is, at a given age, smaller than yellow walleye.
The link between bluish coloring and exploitation of these habitats.
This coloring could prove beneficial to walleye while hunting in deep areas of lakes. It would allow walleye to be less noticeable by prey, thus optimizing the success of individuals with strong blue coloring in the deep areas of the lakes.
More questions ...
Several questions remain, however, pending. It has been observed in the Great Lakes that blue walleye and typical yellow walleye have different spawning periods and habitats.
11 April 2017
By Raphaël Dubé
Gouin Reservoir Management Corporation
Categories : Fishing
Tags : Discoveries