Hey bravo252 - thanks for the info. How many of the ten Rocky Mountain Whitefish (RMW) you hooked were in the Vedder? You were fishing for chinooks and caught whitefish; may I ask your lure or bait?
I am a big fan of RMW; love fishing them and want to learn more of their life history. Greybark, Buck, Lew, and others, thanks for your comments. I suspect the decline of RMW in the Chilliwack - Vedder is a combination of all the mentioned problems, but the fact the upper river is virtually immune to sedimentation and major high water events
makes me think there is something else happening here. Just a few more comments:
I have worked on/fished an interior river nearly every fall for about 35 years - this river is absolutely loaded with RMW and I have caught many at an estimated 3 lbs; measured 20". The largest always are a bronze colour, larger scaled and have a very noticeable hump at the base of the neck, just behind the gills, a feature I have attributed to old age (but have no data to defend).
Once, while crossing a bridge over this river, looking for sockeye, I was fortunate to observe a huge pod of RMW .... this group of fish, at least two layers ( perhaps more) deep covered an area of an estimated 500 square feet ... at least several hundred fish, more likely thousands . Another time, on Elkin Creek, deep in Chilcotin, another pod was observed again near a bridge. In this group there were probably 100 RMW and, in the middle was a very conspicuous individual fish because it was a deep yellow colour ... same size, same traits as the others but stuck out big time due to its colour.
Rocky Mountain Whitefish, along with the invertebrates they depend on may well be the canary for our rivers; I fear we have may have lost that diversity on the Vedder