Hmm, I don't really have much to add that hasn't already been said, but i'll throw my 2c in anyways! Don't be disheartened...they are around, and they are biting...I've been doing pretty well as of late.
Remember:
-short leaders. The sturgeon don't seemed to be nearly as spooked by your rig as you may think. I fish 18" at the very MOST. If fishing smelt/herring/euchalon, no heads, tails, fins, and make sure its straight. Lower it into the water and see if it does a big spiral/loop in the current. If it does, dont even waste your time....bring it in and re-rig it!
-Depth. The higher the river gets the shallower I seem to find the Sturgeon. I'm not saying they aren't in those deep holes, but those shallow backeddys just off the current are certainly worth a couple quick drops to 'test the waters'.
-Check the lines. The Fraser can do some very interesting things to your rig. Nothing more frustrating than waiting 20mins for a hit, pulling in your rig to find your leader managed to crochet itself around your weight. Keep the bait fresh, and work the water. Find where the fish are moving.
good luck! ;D Hope this helps!