I wasn't stating an opinion, it's scientific fact! There is no genetic difference between any 'Blue' pickeral and our everyday 'Yellow' pickeral. There isn't and there was never a genetically seperate subspecies. Despite lots of genetic data being compiled from many hundreds of water bodies there has been no evidence of any seperate subspecies.
Along with blue phase Walleye there are also quite common blue or 'silver' variations of pike along with blue perch. There's also many examples of 'golden' or yellow colour phases in different species, namely the 'Palimino' Trout which is essentially and Albino Rainbow Trout.
There are a few reasons Walleye can take on blueish hue. The one pictured in this thread, being more silverish is likely albino in regards to yellow pigment but lacks the Sandercyanin protein.
Many lakes including some large clear Muskoka lakes and others in NE Ontario and western Quebec in particular have darker Yellow/Green Walleye that will have a natural darker blueish tinge, particularly in the tail which again is just a colour variation without the presence of the blue protein.
Then there's the Sandercyanin producing fish which can be both a typical yellow Walleye that produces the blue tinged mucous or a more vibrant blue varient that is both albino in yellow pigment and secretes the blue mucous.
And of course Lodge owners will do whatever they can to drum up buisness
I'm not sure what you mean by pigments not becoming extinct? Colours aren't something that can really go extinct!?
Perhaps a couple articles will explain the phenomenon better than I have here.
NOTE: the first article below was written before the 2014 genetic studies that confirmed the 'extinct' lake Erie blue pickeral was genetically identical to current stocks.
SCIENCE OF THE BLUE WALLEYE OF CANADA by Dr. Wayne Schaefer As a fish biologist and university professor, I had worked with walleye ...
wayneschaefer.blogspot.com
Josh