Great comments everyone!
I don’t have any theories about the science of how rising or falling barometer pressures would affect fish physiology and their moods directly. I realize the pressure difference itself is miniscule compared to swimming up or down in the water column. Just go SCUBA diving for evidence of that.
Therefore, I think any effect on fish feeding is due to indirect factors. Such as a future indication of water temperature, sunlight, flow rates, food, exposure, etc. And all of these things can affect the various hatches differently, and thus a fishes desire to start feeding.
Perhaps a falling barometer indicates poor weather coming. Therefore, the potential for flash flooding or poor water conditions, therefore fish move to more protected water. The rain and lack of sun could create cooler water temperatures which lowers metabolism and therefore slows feeding.
Perhaps a rising barometer indicates a change to good weather, lots of bugs in the future, warmer water temperatures, and thus the fish get feeding secure in the knowledge that now and the near future is the time to fatten up.
Just my thoughts, feel free to tear them apart either for or against.
And thanks to everyone who is participating with their own ideas.
PS: Just to clarify, I am talking about the Bow River specifically, but anyone’s experience river, lake or ocean fishing is appreciated!