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Posts: 39
| Ok, There is all this talk about the barametric pressure and how it effects fishing but how is that possible. Let me explain. It is my understanding that water can not be compressed. If this is true how could fish tell what the pressure outside of the water is doing.
I hope someone can correct me or explain to me how the fish know.
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Posts: 58
Location: Edina, MN | It is my understanding that a rapid drop in pressure actually causes the stuff on the bottom to percolate (much like when you rapidly lower pressure by opening a can of your favorite carbonated beverage). When this happens small bits of whatever come up into the water column which starts the entire food chain from microscopic organisms right up to the top of the food chain - Muskies. In theory this is why there is a feeding frenzy just before a large storm moves in. High pressure, at its onset, has the opposite effect. Thats at least my understanding of how it works. |
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Posts: 1137
Location: Holly, MI | Deer move too! Animals can feel such subtle changes in atmospheric pressure that humans will never understand it. Moon/sun phases change the gravitational pull on the earth and they can feel that too. No one thing can make or break a day on the water, but if several things are in your favor you might just want to get out there. If the moon is rising as the sun is setting and the weather has been stable for a few days but now is going downhill fast (storm brewing)and the barometer is dropping , I'm making up lies or what ever it takes to hit the water. I'll gladly get wet fishing if the monsters are on the move. |
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Posts: 1939
Location: Black Creek, WI | There was a really cool post about this topic on the Research Board last winter. I believe NXTWRLDRCD started it and was titled something like "Beer Can Barometer" or something to that affect. Might want to try searching for it.
Water may not be compressible.... but that doesn't mean it is not affected by pressure. The deeper you go, the more pressure you encounter. Many fish have swim bladders to control their bouyancy at various depths. As they swim deeper and the pressure increases... the swim (air) bladder shrinks (compresses) and the fish becomes less bouyant.
When a low pressure system approaches, is it possible that the dropping pressure ever so slightly allows the fish's swim bladder to expand... making them more bouyant.... which brings them up shallower.... making them more accesible to our lures or forcing them to swim around making them easier for us to contact???? Pretty far fetched.... but its possible.
I don't know what really happens... but I'm pretty confident a fish can tell when the barameter is moving. Just like when my old man's knee starts to ache just before it rains.
jlong |
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Posts: 2754
Location: Mauston, Wisconsin | Ok- not real scientific but with some basis in physic's, if I remmber all the stuff from scuba diving. http://members.aol.com/profchm/boyle.html. Water is definitely not compressible. But this same fact, makes it an excellent conductor of pressure changes. f. ex. we have a balloon of X volume at a depth of 1 atmosphere, which just so happens to be 33ft. ( a pressure change of 1 atmosphere is ~ 14.7PSI or the ~ weight of the earth's atmosphere at sea level. ) If we change the sea level surface pressure by .5 PSI, the water pressure at the balloon will change by .5 PSI also. The balloon will either deflate slightly or inflate slightly depending on the direction of the pressure change. It is entirely reasonable that fish can utilize a similar mechanisim to detect these subtle changes in water pressure to regulate their day too day activities. The fishes responses are probably genetically imprinted so that minimal or no brain processing is required. Cold front= I'm not eating today. I read somewhere that activity levels of northern pike are not affected by cold fronts as much as muskies or walleye's. This should get some of the fisheries biologists and others to step up to the plate. jlong where are you? Al Warner http://zaltnad.com |
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Posts: 39
| These are all good explanations. I belive that the barametric pressure affects fish I just didn't understand how.
I'll look for that post that jlong mentioned. |
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Posts: 32958
Location: Rhinelander, Wisconsin | Back when I was an 'instructor' at Nicolet College in Rhinelander I ran comparisons of barograph records to my fishing logs. I found a DIRECT correlation between barometric pressure changes and fish activity. Small rises or drops seemd to have an effect, as did, of course, barometric trends. I found that a steady barometer with slight changes up or down seemd to provide consistent action during the peak times, and a sudden drop with the approach of a Low provided short duration but explosive action regardless of peak times (solunars). Rising pressure, especially the VERY first uptick, seemd to produce the best pike action, and for some inexplicable reason, some of my biggest fish. |
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