Has lots to do with the time of year. Here is my observation based on 9 years of fishing in town. We get lots of big fish that come through from about April 15-June 1. A lot of them are allegedly from America or the lower Fraser hatcheries. These fish are usually in deep water way off the fingers, double humps, spoil grounds, entrance island, and neck point. Think 150-200 feet on the rigger sometimes more. 3" green spoons dragged behind glow flashers do a lot of damage at this time of year. Unfortunately, we can't retain fish at that time of year anymore. This was always the best fishing of the year.
From about June 1 to August 10 you get a mixed bag. These fish are usually not as big as the spring or late summer fish but there are usually lots them! During this time sometimes there are fish everywhere, often they only stick around a couple days and move to a new location. Sometimes jigging is good, sometimes trolling is better. If you are not catching fish or you are catching shakers change gear, technique or location, or all of the above.
From August 10 to September 15 is my favorite part of the fishery. Big migratory fish headed for island rivers or the Fraser move into shallow water to feed. Cohos and pinks show up if your into that. Towards the end of August and into September big lings move out of the deep back into shallow water getting ready to spawn with the males that have been nest guarding. August usually has fair winds and nice weather. The best part is that basically every technique works and you can keep 2 super big ones if you find them starting Sept 1. Trolling plugs fast in shallow water, jigging bait balls, dragging cannon balls on the bottom, fishing spoons with no flasher. This usually ends with the first big rain.
From September 15- April 15 there are a million shakers out there. The pros seem to be able to keep finding occasional big ones, but I never do. I guess that's why they are the pros!