Quote:
Originally Posted by Travis C.
Leaving technical mumbo jumbo out, when a front is rolling in it usually brings a pressure change with it. An easy way to look at it is say the distance between the clouds and fish would be the size of a weight they are swimming around with. As a blue sky is pushed out by a front clouds roll in and that distance gets considerably smaller or less in weight terms.
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Well technically, it doesn't have to do with the clouds themselves, of course. I imagine you probably know that, but I guess the illustration could be confusing to some people. Colder air is more dense than warmer air, so it weighs more - so a cold air mass has high pressure and a warm air mass has low pressure.
The "front" is just the edge between the two air masses. Warmer, less dense air holds more moisture, so you get nasty weather at the edge between the cold front and warm front because the warmer air hits that cold air mass, cools down, and the moisture precipitates out.
From the fish's perspective, I'm not sure anybody knows exactly why their feeding is affected by barometric pressure. But fish are extremely sensitive to pressure changes - both their lateral line and their swim bladder respond to extremely minute variations in pressure. Among other things, fish use these organs to determine their position in the water column, since they sense greater pressure as they move deeper. I suppose maybe atmospheric pressure changes are distressing and disorienting to them since they have to cope with that change.
On the other hand, it might not entirely be the pressure at all. Fish are sensitive to sunlight, since they have no eyelids. Some fish are more sensitive than others - walleye are more sensitive to bright sunny days than bass, and bass are much more sensitive than rainbow trout. Browns seem to like low light much better than rainbows too.
High pressure areas tend to coincide with cloudless, sunny days. In addition there may be a temperature drop, which affects metabolism in fish since they're cold-blooded. So who knows, maybe the pressure itself is just a small part of the puzzle.
bd