Was recently in some of the Squamish river tribs and saw huge amounts of Chums spawning
I doubt that as the Squamish is just awful for chum. You would have been on the Cheakamus but it is far from being full of chum. Have spent the last 5 weeks on the river almost daily and I can tell you in the 32 years I have lived in Squamish this is one of the worst returns seen. The Ashlu has a few hundred chum at best, the upper Squamish has localized groups in several of the tributary streams and side channels but the main river is virtually barren of spawners. The Mamquam has at best a couple of thousand fish and the groundwater spawning channels have generally less that a couple hundred each and in several of the channels significantly less that that.
The lower Squamish has fish but not lots of them but enough to catch if you put in your time. You do get fish staging of the mouth of the Cheakamus but this is to be expected. The Cheakamus has the most fish but still not huge amounts of chum. The chum channels have few fish in them except for the Upper Paradise channel which has 1000 fish or so. Big deal. At this time of year spawning should be in full swing with the spawning areas ram jamb full. Not happening. This rain this weekend will be the telling tail. If they don't come now then their not coming.
People who have not experienced what the Squamish chum run was like have no concept of how many fish were here. That was what brought the eagles here and what generated a world record eagle count. Those days are over. The Squamish system should have 300 000+ chum and look like the Stave River. There are may people who can remember trying to fish the Frog Pond on the Cheakamus or Judd Road on the Squamish with lures and just had to give up because of all the foul hooked chum you would encounter. Friends of mine live on Judd Slough and we can all remember the whole neighbourhood smelling like rotten chum salmon for weeks on end. That is also a thing of the past. The chum used to arrive by the first week of October and continue well into mid December with the peak around mid November. The late fish are now for the most part all gone as well. When was the last time anyone has seen January chum?
So what happened? About the time sockeye took their first big crash commercial fishing effort was shifted over to the Johnstone Straight chum fishery which allowed them to plunder as per normal. It's is exactly the same timing as the Squamish chum collapse. The Fraser chum have been able to whether this effort due to a large run size as well as chum enhancement. The Squamish has not and know one in power seems to care.