No one knows why fish return to the same spawning grounds, Eels travel thousands of miles, Salmon, Trout, maybe its comes natural to them from breading.
Fish may not take a hook bait some times, but will take them at other times.
I was fishing a pit with some mates, i was getting the fish, they had nothing. So i told them to try my swim, Nothing, I even gave one my rod, still nothing, yet when i cast, i caught, they didn't.
Now was it something on their hands getting onto the baited hook ?? It had nothing to do with the hook as I caught and they didn't, same rod, rig etc.
I have also heard of others who have had the same thing happen. If fish had a memory as some think, then they would know danger from bait, so they wouldn't go near it. If its a short memory, then its very short, as I have seen the same fish caught just a minute after being return, a Barbel of 13lb 6ozs. I have also seen a pike take a plug 3 times on the trot, having got off the first 2 times.