Barometric pressure????

Wags · 08-22-10, 07:50 PM

I read somewhere that the barometric pressure has an effect on the aggressiveness of fish. I have NO IDEA what the hell that even means. I noticed that a low pressure front was moving towards Michigan this weekend and the bass were unusally agressive at a local tournament, attacking top-water like they hadn't eaten in months. That is what I was lead to believe would occur if the pressure was low. I guess the question would be, is there a particular number for the Barometric pressure to be considered high? or low? I've heard weather people read the barometric pressure number and then say that it is steady (neither rising or dropping). I know this sounds like I'm grasping at straws for a bit of an edge,......but I'm grasping at straws for a bit of an edge !!! Any help in understanding all this would be greatfully appreciated since I probably slept thru this info when I was in science class many moons ago.

Wags · 08-22-10, 09:18 PM

http://www.bassfishin.com/bassfishin...e............I did a search on the site and found some very nice info that should help....I suppose I could have done that first??? LOL

nofearengineer · 08-22-10, 10:14 PM

Here is my take on the barometric pressure issue.

Fish absorb dissolved oxygen through their gills. So naturally, they prefer to stay in water that has the right amount of dissolved oxygen (5-9 ppm for bass).

What happens during falling air pressure is what happens when you take the top off of a soda bottle. Dissolved gases immediately start to come out of solution (carbon dioxide in the case of the soda), and are thus no longer available to the fish. It isn't much, but it does make a difference.

This would cause the fish to move to where the dissolved oxygen is higher; i.e, nearer the surface. However, this does not make them more aggressive. We have to look at other factors to explain their increased feeding.

Bass aren't the only fish in the lake. Bait fish, and all other fish, are subject to their need for oxygen too. Some bait fish are very sensitive to decreased oxygen, so they especially "go shallow" when the barometer falls. This has the effect of concentrating baitfish in surface waters.

When you combine surface predators and surface prey, you have the makings of an all-out slaughter, and memory-making fishing.

walkeraviator · 08-23-10, 07:03 AM

Another consideration here is pressure itself. remember that air pressure means that it is exerting that particular pressure on the surface of teh water and compressing teh water from above... so teh fish feel the increase or decrease in water pressure... and since they have air bladders inside helping with bouyancy, they are greatly affected by the changing pressures... as i have learned it... high pressure shuts bass down... and they love a falling barometer as a front approaches... but i have never actually tried putting this information to use on teh water before...

screwballl · 08-24-10, 02:54 PM

One thing I have seen is the small to medium sized fish like bluegill (at least in my area) seem to shut down completely for a day or two before the low pressure moves in (possibly reserving the oxygen??), yet the few days after when the pressure starts rising is when they go crazy... I have seen that with bass at one specific lake as well... so I think it depends more on what the fish are used to and the available oxygen during these changing weather events...

doc · 08-25-10, 12:41 PM

Quote:

Originally Posted by walkeraviator

Another consideration here is pressure itself. remember that air pressure means that it is exerting that particular pressure on the surface of teh water and compressing teh water from above... so teh fish feel the increase or decrease in water pressure... and since they have air bladders inside helping with bouyancy, they are greatly affected by the changing pressures... as i have learned it... high pressure shuts bass down... and they love a falling barometer as a front approaches... but i have never actually tried putting this information to use on teh water before...

I've allways thought that changes in water depth would exert more pressure than the barometer moving up or down a bit.

Dave63 · 08-25-10, 05:35 PM

Low or high if it's stable and stays that way for a few days, they seem to bite OK. Transition times are good. The first day when it stabilizes after it moves can be tough. Just my observation

XIntel007 · 08-25-10, 08:17 PM

Walker, I have to believe that water does not compress but the rest of you post seems logical. I would submit that falling pressure makes it easier for the bass to rise given the pressure in their bladders but this is a guess.

walkeraviator · 08-26-10, 10:47 AM

hey i am just goin with what i have read and seen on shows... doesnt mean its all right...

but i do agree with bass turning on with a coming front and shutting down in high pressure situations..

HarveysMinnow · 09-08-10, 12:12 PM

Quote:

Originally Posted by XIntel007

Walker, I have to believe that water does not compress but the rest of you post seems logical. I would submit that falling pressure makes it easier for the bass to rise given the pressure in their bladders but this is a guess.

I realize this is an older post, but let me just say that XIntel is right in saying that water (and other liquids) are almost non-compressable. However, the effect of changing barometric pressure is transmitted through the water and thereby affects the fishes air bladders. Consider the Cartesian Diver physics experiment:

http://www.youtube.com/watch?v=Xf5u2...eature=related

When the guy adds pressure to the closed container, the pressure increases in the 'diver' and the air space in it decreases, allowing additional water into the diver. This in turn makes the diver heavy enough to sink to the bottom of the container.

.

walkeraviator · 09-08-10, 03:52 PM

Yes... the term compressibility is kind of misleading when talking about Liquids. One of teh Physics 101 definitions of a liquid is that it cannot be compressed. What this means is that as pressure increases, volume stays constant. Which means that yes the pressure of a liquid will increase when acted on by air pressure... the difference is that teh volume will remain unchanged. A gas in constrast will decrease in volume when acted on by outside pressures... and it will seek to equalize pressure with the exterior force instead of maintaining volume...

Tavery5 · 09-08-10, 07:14 PM

High
Clear skies
Fish slow down, find cover or go to deeper waters.
Slow down lures and use baits more attractive to fish. Fish in cover and in deeper waters.

Rising
Clearing or improving
Fish tend to become slightly more active
Fish with brighter lures and near cover. Also fish at intermediate and deeper depths.

Normal and stable
Fair
Normal fishing
Experiment with your favorite baits and lures.

Falling
Degrading
Most active fishing
Speed up lures. Surface and shallow running lures may work well.

Slightly lower
Usually cloudy
Many fish will head away from cover and seek shallower waters. Some fish will become more aggressive.
Use shallow running lures at a moderate speed.

Low
Rainy and stormy
Fish will tend to become less active the longer this period remains.
As the action subsides, try fishing at deeper depths

I find this chart to be fairly acccurate with the fishing in my area

Old Hooker · 09-13-10, 10:20 AM

Some of my best fishing (ecspecially top water) has been as a storm was coming in and the pressure was dropping. Once the storm arrived the bite turned off, but it was great for about 30 minutes each time.

thekevster · 09-13-10, 06:46 PM

To be honest I have never really thought about barometric pressure when bass fishing it could be helpful to take that into account but the problem is you never really know what the barometric pressure is you can only guess and it varies with elevation and weather patterns.I think more about the weather how cold it is how hot it is how cloudy etc etc,Tavery5 has got a pretty good chart and in most cases I would say that is pretty reliable but it all depends on were you live the best way to figure out your area is to fish it.

coachpurdy · 09-13-10, 10:13 PM

Two things I have noticed in changing pressure. 1 the vibration of a large spinnerbait can change in different pressures. when it is high you tend to feel less vibrations
2 also I've noticed that smoke will not rise the same which can affect your deer hunting, but take a look at chimneys or i just maybe crazy

TN_Bassin · 09-13-10, 10:33 PM

Call me dumb but I find that a pretty accurate way to measure pressure is to look at things floating in the water(mainly sticks or logs). If the majority of what you see is sticking straight up and down then you have high pressure. The opposite is true for low pressure. The debris would be floating on it's side. Dunno if anyone has noticed this, but i've checked the weather a few times to check it; nearly always, it was accurate. The reason pressure affects sticks and logs so much could be because of the miniscule amount of air in the pores of the wood. And to tell you the truth I consider pressure, the barometric kind as well as the human kind, just about every time I hit the water.

thekevster · 09-14-10, 01:30 PM

Quote:

Originally Posted by TN_Bassin

Call me dumb but I find that a pretty accurate way to measure pressure is to look at things floating in the water(mainly sticks or logs). If the majority of what you see is sticking straight up and down then you have high pressure. The opposite is true for low pressure. The debris would be floating on it's side. Dunno if anyone has noticed this, but i've checked the weather a few times to check it; nearly always, it was accurate. The reason pressure affects sticks and logs so much could be because of the miniscule amount of air in the pores of the wood. And to tell you the truth I consider pressure, the barometric kind as well as the human kind, just about every time I hit the water.

Thats a pretty good idea

has anyone else noticed anything similar?

walkeraviator · 09-14-10, 02:04 PM

I usually check the barmoter before heading out by checking the weather reports at the nearest airport...

Look up METARs for teh nearest airport and the presure is listed...

nofearengineer · 09-14-10, 02:24 PM

Quote:

Originally Posted by TN_Bassin

Call me dumb but I find that a pretty accurate way to measure pressure is to look at things floating in the water(mainly sticks or logs). If the majority of what you see is sticking straight up and down then you have high pressure. The opposite is true for low pressure. The debris would be floating on it's side. Dunno if anyone has noticed this, but i've checked the weather a few times to check it; nearly always, it was accurate. The reason pressure affects sticks and logs so much could be because of the miniscule amount of air in the pores of the wood. And to tell you the truth I consider pressure, the barometric kind as well as the human kind, just about every time I hit the water.

You know, this sounds crazy, but if you think about it, there is a certain logic to it. I never paid that much attention to it...sort of like "do you breathe in or out on your backswing?" in golf. Now I won't be able to stop thinking about it when fishing.

XIntel007 · 09-15-10, 10:08 AM

Great discussion. I suppose if I thought about Ideal Gas Law (pV=nRT) it would make even more sense.

I pull the barometric pressure from my truck before I go out. I have an Insight gauge that lets me pull the barometric pressure readings from the engine management computer.

08-22-10, 07:50 PM	#1
Wags BassFishin.Com Active Member Join Date: Sep 2007 Location: Swartz Creek, Michigan Posts: 163	Barometric pressure???? I read somewhere that the barometric pressure has an effect on the aggressiveness of fish. I have NO IDEA what the hell that even means. I noticed that a low pressure front was moving towards Michigan this weekend and the bass were unusally agressive at a local tournament, attacking top-water like they hadn't eaten in months. That is what I was lead to believe would occur if the pressure was low. I guess the question would be, is there a particular number for the Barometric pressure to be considered high? or low? I've heard weather people read the barometric pressure number and then say that it is steady (neither rising or dropping). I know this sounds like I'm grasping at straws for a bit of an edge,......but I'm grasping at straws for a bit of an edge !!! Any help in understanding all this would be greatfully appreciated since I probably slept thru this info when I was in science class many moons ago.

08-22-10, 10:14 PM	#3
nofearengineer BassFishin.Com Premier Elite Join Date: Mar 2009 Location: Southwest IN Posts: 5,630	Here is my take on the barometric pressure issue. Fish absorb dissolved oxygen through their gills. So naturally, they prefer to stay in water that has the right amount of dissolved oxygen (5-9 ppm for bass). What happens during falling air pressure is what happens when you take the top off of a soda bottle. Dissolved gases immediately start to come out of solution (carbon dioxide in the case of the soda), and are thus no longer available to the fish. It isn't much, but it does make a difference. This would cause the fish to move to where the dissolved oxygen is higher; i.e, nearer the surface. However, this does not make them more aggressive. We have to look at other factors to explain their increased feeding. Bass aren't the only fish in the lake. Bait fish, and all other fish, are subject to their need for oxygen too. Some bait fish are very sensitive to decreased oxygen, so they especially "go shallow" when the barometer falls. This has the effect of concentrating baitfish in surface waters. When you combine surface predators and surface prey, you have the makings of an all-out slaughter, and memory-making fishing. __________________ Many men go fishing all of their lives without knowing it is not fish they are after.

09-13-10, 10:20 AM	#13
Old Hooker BassFishin.Com Active Member Join Date: Sep 2010 Location: Shadow of the Smokys, East Tennessee Posts: 249	Some of my best fishing (ecspecially top water) has been as a storm was coming in and the pressure was dropping. Once the storm arrived the bite turned off, but it was great for about 30 minutes each time. __________________ To fish or not to fish. What a stupid question! -Jim

09-13-10, 10:33 PM	#16
TN_Bassin BassFishin.Com Super Veteran Join Date: Nov 2009 Location: Bon Aqua,TN Posts: 1,013	Call me dumb but I find that a pretty accurate way to measure pressure is to look at things floating in the water(mainly sticks or logs). If the majority of what you see is sticking straight up and down then you have high pressure. The opposite is true for low pressure. The debris would be floating on it's side. Dunno if anyone has noticed this, but i've checked the weather a few times to check it; nearly always, it was accurate. The reason pressure affects sticks and logs so much could be because of the miniscule amount of air in the pores of the wood. And to tell you the truth I consider pressure, the barometric kind as well as the human kind, just about every time I hit the water. __________________ Other anglers are tough, but the fish are the real competition.

08-22-10, 09:18 PM	#2
Wags BassFishin.Com Active Member Join Date: Sep 2007 Location: Swartz Creek, Michigan Posts: 163	http://www.bassfishin.com/bassfishin...e............I did a search on the site and found some very nice info that should help....I suppose I could have done that first??? LOL

08-23-10, 07:03 AM	#4
walkeraviator BassFishin.Com Super Veteran Join Date: Apr 2010 Location: Louisville, KY Posts: 1,119	Another consideration here is pressure itself. remember that air pressure means that it is exerting that particular pressure on the surface of teh water and compressing teh water from above... so teh fish feel the increase or decrease in water pressure... and since they have air bladders inside helping with bouyancy, they are greatly affected by the changing pressures... as i have learned it... high pressure shuts bass down... and they love a falling barometer as a front approaches... but i have never actually tried putting this information to use on teh water before...

08-24-10, 02:54 PM	#5
screwballl BassFishin.Com Veteran Member Join Date: Feb 2010 Location: NWFL Posts: 654	One thing I have seen is the small to medium sized fish like bluegill (at least in my area) seem to shut down completely for a day or two before the low pressure moves in (possibly reserving the oxygen??), yet the few days after when the pressure starts rising is when they go crazy... I have seen that with bass at one specific lake as well... so I think it depends more on what the fish are used to and the available oxygen during these changing weather events...

08-25-10, 05:35 PM	#7
Dave63 BassFishin.Com Active Member Join Date: Jun 2010 Location: Farmersburg, IN Posts: 341	Low or high if it's stable and stays that way for a few days, they seem to bite OK. Transition times are good. The first day when it stabilizes after it moves can be tough. Just my observation

08-25-10, 08:17 PM	#8
XIntel007 BassFishin.Com Active Member Join Date: Jul 2010 Location: Woodbridge, VA Posts: 102	Walker, I have to believe that water does not compress but the rest of you post seems logical. I would submit that falling pressure makes it easier for the bass to rise given the pressure in their bladders but this is a guess.

08-26-10, 10:47 AM	#9
walkeraviator BassFishin.Com Super Veteran Join Date: Apr 2010 Location: Louisville, KY Posts: 1,119	hey i am just goin with what i have read and seen on shows... doesnt mean its all right... but i do agree with bass turning on with a coming front and shutting down in high pressure situations..

09-08-10, 03:52 PM	#11
walkeraviator BassFishin.Com Super Veteran Join Date: Apr 2010 Location: Louisville, KY Posts: 1,119	Yes... the term compressibility is kind of misleading when talking about Liquids. One of teh Physics 101 definitions of a liquid is that it cannot be compressed. What this means is that as pressure increases, volume stays constant. Which means that yes the pressure of a liquid will increase when acted on by air pressure... the difference is that teh volume will remain unchanged. A gas in constrast will decrease in volume when acted on by outside pressures... and it will seek to equalize pressure with the exterior force instead of maintaining volume...

09-08-10, 07:14 PM	#12
Tavery5 BassFishin.Com Super Veteran Join Date: Dec 2009 Location: Wichita, KS Posts: 2,427	High Clear skies Fish slow down, find cover or go to deeper waters. Slow down lures and use baits more attractive to fish. Fish in cover and in deeper waters. Rising Clearing or improving Fish tend to become slightly more active Fish with brighter lures and near cover. Also fish at intermediate and deeper depths. Normal and stable Fair Normal fishing Experiment with your favorite baits and lures. Falling Degrading Most active fishing Speed up lures. Surface and shallow running lures may work well. Slightly lower Usually cloudy Many fish will head away from cover and seek shallower waters. Some fish will become more aggressive. Use shallow running lures at a moderate speed. Low Rainy and stormy Fish will tend to become less active the longer this period remains. As the action subsides, try fishing at deeper depths I find this chart to be fairly acccurate with the fishing in my area

09-13-10, 06:46 PM	#14
thekevster BassFishin.Com Member Join Date: Jul 2010 Location: Florida Posts: 72	To be honest I have never really thought about barometric pressure when bass fishing it could be helpful to take that into account but the problem is you never really know what the barometric pressure is you can only guess and it varies with elevation and weather patterns.I think more about the weather how cold it is how hot it is how cloudy etc etc,Tavery5 has got a pretty good chart and in most cases I would say that is pretty reliable but it all depends on were you live the best way to figure out your area is to fish it.

09-13-10, 10:13 PM	#15
coachpurdy BassFishin.Com Active Member Join Date: Jul 2010 Location: coffeeville, ms Posts: 143	Two things I have noticed in changing pressure. 1 the vibration of a large spinnerbait can change in different pressures. when it is high you tend to feel less vibrations 2 also I've noticed that smoke will not rise the same which can affect your deer hunting, but take a look at chimneys or i just maybe crazy

09-14-10, 02:04 PM	#18
walkeraviator BassFishin.Com Super Veteran Join Date: Apr 2010 Location: Louisville, KY Posts: 1,119	I usually check the barmoter before heading out by checking the weather reports at the nearest airport... Look up METARs for teh nearest airport and the presure is listed...

09-15-10, 10:08 AM	#20
XIntel007 BassFishin.Com Active Member Join Date: Jul 2010 Location: Woodbridge, VA Posts: 102	Great discussion. I suppose if I thought about Ideal Gas Law (pV=nRT) it would make even more sense. I pull the barometric pressure from my truck before I go out. I have an Insight gauge that lets me pull the barometric pressure readings from the engine management computer.

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