Barometric pressure

Pat, at this point, I see this as apples and oranges.

I challenge that a small, slow change, as would be due to atmospheric pressure changes, affects their behavior when much larger, faster pressure changes are part of their everyday lives.
Click to expand...

So, you are arguing whether a fish can tell where it is at at any given time, and whether or not they moved. ;-) (joking, no need to answer)

I also believe they can sence the pressure change from the lunar cycle, even in a stream where tide is immeasurable, but that is another story.

I'm not convinced either way on the barometric, but lean towards the idea that they can feel it and can tell the difference from other causes. Like the fish in my pond recognize that a certain pattern of pressure change meant food was coming, and they adapted.

From the angler standpoint, it really doesn't matter what the fish is reacting to, only that they are, or will be reacting if a low pressure is coming through.


 
Pat,

If you have the time, listen to the podcast link I posted, previously. It is commentary from a Phd in fish nuerobiology from Stanford. Interesting stuff. Many things discussing included the effect on westher pressure changes on fish.

 
poopdeck wrote:
I can only add for SMB since trout are of little interest to me. Basically I only care if the water is at fishable levels. I don't concern myself with pressure, moon phases, temperatures, sun, clouds, tides (unless I'm fishing tidal water), sun spots or anything else. I would say the only thing that matters is ones ability to get out and actually present something the way it should be presented. Everything else is minutia. I would drive myself mad if I had more factors to concern myself with. I guess I didn't help at all.
Click to expand...

No you didn't, but it was a good point. ;-)

I'm the same way. Finding time to actually fish is a biggest deal by far. I don't really care about the rest, other than it's fun to discuss.

Even when my feed mill calendar says it will be a bad fishing day, I'm not going to change my mind and decide not to fish.

BTW, my feed mill calendar says that after tiday, it's going to suck for the next 5 days.;-)

 
While trout are able to adjust on the fly (pun intended) to rise through the water column, perhaps that is a lesser burden than the constant pressure imposed by an abrupt atmospheric change.

As far as a passive effect due to cloud cover etc, that's a no brainer, under most circumstances. But there are a number of places in which fish sit right out in the open on sunny days, in flat shallow water, and are very active. It's places like this which make me wonder if there is a direct affect on fish due to pressure, since shallow water exerts less pressure on them, and a fish rising for a dry fly from a "deep" hole isn't expending any great amount of energy to do so, but is very much lethargic for whatever reason.

I'll definitely give the podcast a listen.
 
I am going to venture to say that the lateral line plays the most important role in the fishes life. Since all fish have them and they use it to detect predators among other things not yet known to mankind. The change in pressure might be viewed by the fish as danger approaching (predator fish) and therefore the fish stays in closer to the protection and in turn eats less. Only to venture out when danger (high front/low front) has moved away. You might say that you see some fish that don't adhere to the equation. Which is similar to what we humans do when we feel it's in the best of our interest.

I am not stating that you cannot catch fish during a pressure change. Make it a challenge, test your skills, try different tactics, learn something new and always remember to safeguard your life first. Take notice of your surroundings, continuously make an escape plan as you go.

This last weekend my car started acting strange after getting gas at Wawa's. So I have been walking to the bus stop this week. Would'nt you know it, that a car accident happened last night right where I have parked my car at least 500 times,near the train station. God has my back!
 
Common FD Couldn't you tell it was a joke? Anyways what does the Farmer's Almanac say about fishing this weekend?
 
Like FD I have to visit the Dr. In brief. IMO it's the whole, pressure/ Lunar phase/ water temp. combined. GG
 
PennypackFlyer wrote:
Common FD Couldn't you tell it was a joke? Anyways what does the Farmer's Almanac say about fishing this weekend?
Click to expand...

PPF, there is nothing common about me.

Of course I could tell that you were joking. So was I cept for the part about Pat being a smart feller.
 
My argument is a signal to noise ratio argument, I suppose.

A run of the mill low or high pressure system moving in changes the pressure a fish feels by a moderate amount over a period of hours.

Going to a shallower or deeper spot changes the pressure a fish feels by a large amount over a period of seconds.

The part I was railing against was really the swim bladder thing. PHD from Stanford or not (degrees don't impress me much, I have one too, and divorced a woman with one!). It does not make physical sense to me that a fish has systematic, biologic difficulty with slow minor pressure changes due to atmosphere when they live in an environment with rapid massive pressure changes due to depth, current variations, etc. If rapidly dropping atmospheric pressure inflates their swim bladder, then coming out from below that waterfall would blow them up. Think the ending to Jaws here. Lol. Boom!

As for a tendency to "shut off" due to conditioning when they sense a particular style of pressure change? Yeah, it's possible. My own history says a rapidly dropping barometer = excellent fishing, all else being equal. But my observational opinion is that it has more to do with clouds, temperature, and water flow/color, as well as the tendency of other fishermen to disappear from the stream!!!!
 
Degrees don't impress me much either. There are a million+ things to learn about and if a person becomes an expert in 0.1% of what is available and still remains personal, they're ok with me.

 
pcray1231 wrote:

My argument is a signal to noise ratio argument, I suppose.
Click to expand...

Wanna buy my copy of Principles of Underwater Sound by Robert J. Urick? I had him sign it. ;-)

The part I was railing against was really the swim bladder thing. PHD from Stanford or not (degrees don't impress me much, I have one too, and divorced a woman with one!). It does not make physical sense to me that a fish has systematic, biologic difficulty with slow minor pressure changes due to atmosphere when they live in an environment with rapid massive pressure changes due to depth, current variations, etc. ...
Click to expand...

I do agree with you on that.

BTW, I knew your ex is a PHD and was going to joke about that not meaning much to you anymore, but I decided not to. Then you did.
Good to see you can joke about it.
 
Barometric pressure effecting fish and fishing seems to be pretty universal with everything I read.

Here is an article that explains it in a concise manner and pretty much sums up what I read on the subject and confirmed by my experience on the water:

How does barometric pressure affect fish?

A fish senses pressure changes through its air bladder.
Fish that have small air bladders don't seem to be as affected by barometric changes as those with large bladders. But remember, forage fish they feed on have air bladders, and that alone could have a big impact on where you might find fish and how they behave.

Fish with large bladders quickly sense when the air pressure is dropping, because there's less pressure on their bladder.
And when there's less pressure squeezing their bladders, the bladders expand a bit.
When their bladders expand, fish become uncomfortable.
They relieve their discomfort by moving deeper or by absorbing extra gas in their bladders.

Does Low Pressure mean slow Fishing?

Fish are much more comfortable when there's stable high pressure, and will tend to feed actively most anywhere within the water column. Also with passing of several cold fronts in quick succession with cycles of high and low pressure definitely changes how fish react to pressure changes.

The fish can sense that the pressure is dropping in front of storm system. So, as the high pressure begins to dissipate, the fish respond with a change in feeding patterns. Fish often feed heavily right before the pressure drops. When the front passes and high pressure moves back in, the fish may not feed aggressively for at least 24 hours, since they're still adjusting.

"However, it's a different story a day or two after a high settles back in. The fish will have had time to stabilize and an intense bite can occur. When the pressure changes again, such as when another front moves in, the cycle repeats itself."

Link to source: https://www.arkansasstripers.com/how-does-barometric-pressure-affect-fishing.htm
 
Three years ago I would have completely agreed with Pat. Then came Meniere's. A disease that impacts the inner ear. Prior to treatment a passing front with just a 0.5 inHG change in pressure could put me on the floor in a state of extreme vertigo. A change of 0.3 inHG under the right conditions can make me wobbly. Now I'm convinced that biological systems can be impacted by relatively small changes in pressure. I've noticed these impacts from driving/riding down steep hills. 322 at Seven Mountains a prime example. In my case blood pressure is also a factor. Low blood pressure being more susceptible, high blood pressure much less.

After these experiences the barometric theory seems much more plausible to me. Especially when applied to lakes and ponds.

 
If I am wrong, then I will accept it.

The problem I'm having isn't that fish can't sense pressure changes. They can. And they may even react to it as they would to a sound or a shadow. Conditioned response.

The part that sticks me is the biological response. I've got a degree in physics. I understand pressure. It's that the pressure on a fish is atmospheric PLUS water pressure. And water pressure changes substantially with depth. Like I said, if you do the math, if you changed suddenly from a typical high to a typical low pressure system, it'd be like the fish was raised from a depth of 3 ft to a depth of 2. About a foot of difference. Over, what, several hours if it's a very fast moving system?

These are fish we observe holing up in deep spots on a hot sunny day and come up to a shallow riffle, or shallow edge water, to feed in the evening or when a hatch is on. When the spinners fall, pods of them rise from the bottom and hang out just below the surface and pac man at spinners coming downstream. These are considerably larger changes in pressure than can be caused by weather.

And if a swim bladder expands due to a drop in atmospheric pressure, then the effect would be threefold when that big brown moves out of his 5 foot hole to 2 feet of water to feed in the evening, even without a weather change.

Franklin, we're humans, we live outside of water, stuck to the ground, in a much more pressure stable environment. This situation is more like saying an eagle would have a biological issue with a 20 ft elevation change over a period of hours, despite the fact that it voluntarily flies 300 feet in the air, descends to 100 to perch, ascends back to 300, dives to 0 to catch a fish, ascends to 200 to fly back to the nest 100 feet over the ground.

Does an eagle know it's 20 foot high? Sure. Might it be conditioned that if its elevation rises slowly against its will, it should hunker down because something bad is coming? Maybe. Yeah, that's possible. But does it have a biological issue because of a small change in elevation? No, that's preposterous. It's an animal that was MADE to adapt to very sudden elevation changes! If 20 feet are going to cause issue, that's a sick bird.

Fish live in an environment with massive pressure changes from place to place, and they move around in that environment. The change in atmospheric pressure is minimal in comparison.
 
pcray1231 wrote:
If I am wrong, then I will accept it.

The problem I'm having isn't that fish can't sense pressure changes. They can. And they may even react to it as they would to a sound or a shadow. Conditioned response.
Click to expand...

I'll take that as a win. LOL! Joking of course.
 
pcray1231 wrote:
If I am wrong, then I will accept it.

The problem I'm having isn't that fish can't sense pressure changes. They can. And they may even react to it as they would to a sound or a shadow. Conditioned response.

The part that sticks me is the biological response. I've got a degree in physics. I understand pressure. It's that the pressure on a fish is atmospheric PLUS water pressure. And water pressure changes substantially with depth. Like I said, if you do the math, if you changed suddenly from a typical high to a typical low pressure system, it'd be like the fish was raised from a depth of 3 ft to a depth of 2. About a foot of difference. Over, what, several hours if it's a very fast moving system?

These are fish we observe holing up in deep spots on a hot sunny day and come up to a shallow riffle, or shallow edge water, to feed in the evening or when a hatch is on. When the spinners fall, pods of them rise from the bottom and hang out just below the surface and pac man at spinners coming downstream. These are considerably larger changes in pressure than can be caused by weather.

And if a swim bladder expands due to a drop in atmospheric pressure, then the effect would be threefold when that big brown moves out of his 5 foot hole to 2 feet of water to feed in the evening, even without a weather change.

Franklin, we're humans, we live outside of water, stuck to the ground, in a much more pressure stable environment. This situation is more like saying an eagle would have a biological issue with a 20 ft elevation change over a period of hours, despite the fact that it voluntarily flies 300 feet in the air, descends to 100 to perch, ascends back to 300, dives to 0 to catch a fish, ascends to 200 to fly back to the nest 100 feet over the ground.

Does an eagle know it's 20 foot high? Sure. Might it be conditioned that if its elevation rises slowly against its will, it should hunker down because something bad is coming? Maybe. Yeah, that's possible. But does it have a biological issue because of a small change in elevation? No, that's preposterous. It's an animal that was MADE to adapt to very sudden elevation changes! If 20 feet are going to cause issue, that's a sick bird.

Fish live in an environment with massive pressure changes from place to place, and they move around in that environment. The change in atmospheric pressure is minimal in comparison.
Click to expand...

I understand your argument. I've got an engineering degree so from a purely analytical perspective I agree. But there are biological systems that apparently can sense very small environmental changes. I think we are far from understanding these and how they play into various life forms.

I know that in my case my blood pressure is a factor. If my blood pressure is higher there is much less effect. Lower and greater effect. Being an engineer I documented a lot of this for my doctors. Who showed no interest. Could barometric pressure affects on fish have a relationship to activity levels?

I think your a hunter. Ever go to the range and shoot without ear protection? You feel the effects. Ever shoot a deer while you weren't wearing ear protection and not feel any effects of firing? Ear not ringing? Why?

Years ago I read some papers on bass behavior relative to barometric pressure. Have to check and see what is new and if any narrow this down better.
 
The Barometric pressure effects humans as well....we just ask, "Is there a full moon out?" or "Is it Friday the 13th?" when the crazies seam to be more noticeable.

Do fish use thermals like birds do?
 
I agree the effect of barometric pressure seem infinitesimal vs the pressure changes at different water depths. I would assume the fish biologists are aware of this also, so I can't explain why it would have such a effect.

Pat, I researched the subject and found the same argument you bring up on another site >

https://boards.straightdope.com/sdmb/showthread.php?t=818031

 
If we are talking swim bladders only, id think thered be a much larger effect from atmospheric pressure via dissolved gases in the water. The air in the swim bladder doesnt come from atmosphere, save that a few species of fish do gulp air. But for most it comes from the water.

High pressure = more air dissolved in water. Lower the pressure, and gases escape from the water. Just like opening a 2 liter of cola.

That could affect swim bladders. Although in low pressure the bladder would contract then due to less air in the water, opposite of the propised effect.

Perhaps more likely is that lower pressure also means lower oxygen levels. And oxygen levels strongly influence metabolism. Lowerinh pressure may have same effect on fish metabolism as raising the temperature a degree or 3. I'll have to look into how much.
 
Great conversation guys!

I posit an additional question. What effect does geo-electric/geo-magnetic storms have on fish?

They must be able to sense an impending thunderstorm...

What it means to them I haven’t a clue.
 
You must log in or register to reply here.

Latest posts

Montana Angler Fly Fishing
Montana Angler Fly Fishing
Harman's North Fork Cottages


Real Time Data From
the USGS Site

Share this page

Back
Top