BwiBwi - white spring is sold in many specialty seafood shops locally...they market it as "ivory spring" HA!
It respresents a small percentage of the overall chinook harvest and its presence in any catch is hit and miss so it can be hard to find due to its irregular availability.
In terms of a fish's freshness, about 6 weeks ago I BBQd my last 2004 coho. It was frozen whole in late NOVEMBER and was an awesome table fish!
A fish's flesh quality is highly dependant on the species and the amount of time they have been in the fresh water but after many years of fishing, by looking at a fish and gently feeling it, I have a pretty good idea of what the flesh is like on the inside.
So sure fresh or even ocean fish will be better quality than one that been in the river but if you know what to look at, I think you can minimise your harvesting of sub par fish...I just find that no matter what, whites turn WAY to quick and when most of us access them in the vedder, they are well past their prime.
I will admit I harvested a white on the fraser last year and it was a very nice table fish...woulda traded it for a red in a heart beat tho