As Fisherman Dave said, the more pressure there is, the less they bite. It's the same with EVERY other species of fish, not just salmon.
That's why cramming so many anglers into one pool makes no sense at all. The more lines drifting by, the more they spook. I wish people would realize that. :roll: And all the people popping floats all the time scare the fish as well. If you actually watch and pay attention, you will see the fish tail give an extra kick whenever a float is popped. They sense it by their lateral line, especially in a slow pool.
When fishing lures, the fish will quickly tell you if they want it or not. You usually get hit within the first few casts or swings. If you see the fish moving away, or the tail kicking when the lure lands in the water, the fish is already spooked and very unlikely to hit. This is where the fly often have an advantage over lures with less spook factor (quieter entry into the water and less noisy vibration/wobbling). Sometimes the fish key in on noise to trigger aggression. Sometimes they get spooked by it regardless of how aggressive the fish can be.
When they are spooked, you may sometimes see the whole pool of fish scramble and scatter everywhere as soon as the lure lands in the water. It's almost pointless targeting those fish. Just a waste of time. But if there is a fish in the pool that wants it, you will often see it chase or take the lure, and at times swimming across the pool to hit the lure. I've seen salmon came out of a log jam to hit a lure 15 feet way that I was drifting in a deeper run. I wasn't even aware that there was a salmon under the log jam (I have a suspicion, but not a visual confirmation).
You just have to try different presentation or different lures for EACH individual fish. Just like people, each fish has a slightly different mood and may require a slightly different approach. I've had fish ran off before I could even get 20 feet to it. For fish like that, I would need to do long downstream drift to swing the lure to the fish so my presence doesn't scare it off. Then there are fish I can literally kick with my feet and I could bounce the spoon off its nose to get a hit.
The same can apply for piers too. Sometimes, the fish will just shut off with too many people casting into the water, especially when there are snagging lines in the water and the fish constantly run into or rub onto the lines. They simply get spooked, switching from aggression to evasion.
The more time on the river, the more you'll realize the nuance of fishing...including salmon fishing. All it takes is an eye for details and subtle differences to put it all together in your head. ;-)
