I never stopped to wonder what happens to fish when calendars and forecasts project a "bad fishing week". This can happend based on the moon/tides/winds, the effect is less successful fishing, but what are fish doing?

Are fish more scattered? Feeding less? I assume tey need to eat no matter what, and I speculate maybe they are just less aggressive at specific times, or have moved further out. But they sure can't go on a diet.
What is the consensus?