you might be talking about barometric pressure,I think when the barometric pressure falls or gets lower,I think the fish dont bite as well Im thinking its because of the air blatter,and just as a tire innertube gets larger when you pump in more air,a fishes blatter works the same way but in reverse,it will get larger because of pressure being lower,and i think they fell bloated,and thats why they dont bite as quick...then when the barometric pressure goes back up,they get that hungry feeling. correct me if im wrong