I think Zackattack hit the nail on the head about the Vedder.
I had the opportunity to tour the upper Vedder with someone from the salmonid enhancement program earlier this year and was told that all the habitat creation works along the river have doubled the number of pinks returning over the last 20 years, as well as increasing other runs substantially.
The impression I got was that DFO is mandated to provide recreational opportunities in this region (including retention) and the strategy so far has included focusing fishing pressure on the Vedder because it is already urbanized and degraded, has decades of data available, and has heavily augmented conditions that essentially guarantee continued viable populations.
I'm not sure whether this strategy encourages more people to fish all season and elsewhere, or satisfies some fishing angst that would otherwise be directed at more vulnerable fisheries, but I think the strategy is a good way to provide recreational fishing opportunities nonetheless.
Of course more enforcement and education would be better (and DFO knows this), but our current federal government has eliminated that possibility through budget cuts in 2012 and 2013. Maybe next year...
P.S. If you ever get a chance to walk through the trails around the fish habitat works it's absolutely gorgeous, textbook perfect spawning habitat stretching many kilometers.