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beachcomber

Barometic pressure effect

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Man you are going to open a can of worms on this one. Reason being is there are so many possible reasons and ways that bass are affected by frontal systems passing. Notice I said frontal system passing. If high pressure is constant, the affect is minimal. It is after the pressure drops during a frontal passage and high pressure builds back up after the front moves through, that is when the effect that you are referring to occurs. If you give the fish a couple days after the front then things will stabilize and go back to "normal". If you you have to fish the day after a frontal passage, then be prepared for a tough bite. Not only will bass go deeper, but they will also bury up in the nastiest stuff you can find to flip into. If don't have any cover to fish, then try finding vertical strucure.

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The barometric pressure apparantly has much less impact on river fishing, it's ALL about current.  You may find this hard to believe but we had our best day of the fall season fishing for smallmouth on the Tennessee River, Saturday November 20th.  A cold front moved through raising the pressure from 29.7 in the morning to 30.2 in the afternoon.  A ten to fifteen degree drop in temperature and bluebird skies. Caught 23 smallies, five 4 lbers, one 5 llb.  Go figure.

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That is true road warrior. The river bass is less effected by a frontal passage, and it does have to do with the current.  I wrote my post in reference to lake and ponds in general. Most of the rivers where I live contain mostly trout, so I normally forget about writing anything about them as I don't fish them that often.

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Thanks for replys..... I have asked this question on other boards without any replys.. I have a better understanding of the effects now.... Going fishing today pressure 30.04 & rising  Front came thru yesterday  I'll see if I can find them   Thanks again

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Hey beachcomer, if you're fishing a lake you best heed ernel's advice and try going tomorow or Sunday. 30.04 and rising is a recipe for lockjaw. If you go anyhow, I would recommend that you use live bait.

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Gotta go today  Been too long since last week... I plan on going all next week also   Just gotta get out on the water   Will be on Lake Conroe just north of Houston,Tx..  

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Hope ya hook em. The nastier it looks, the better the spot is to drop a lure.

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Well I didn't get shunked..........Bites were very lite Even when I would let them swim with it still no hook ups.... The first one I caught almost swallowed it Ilet him take it so long (3 1/2" purple tube t-rigged) Water was 57 temp. about 55 air temp.. 2 hrs later caught second one on lay down near shore Both were in creeks largest about 2 lbs. First in 4 1/2' sec 2 to 3'

It was fun even if they were small Next week looks good from the forecast Hope to do better then Tight lines all Paul

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I Try to keep it simple deep fish and current fish are less effected by barometric pressure changes. Shallow fish stay shallow but will move into cover more. High pressure changes fish will be in cover or on the bottom so i throw jigs or try to fish close to cover. Low pressure fish are going to be active and can be caught on faster moving lures and will not relate to the bottom as much.

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If a specific number (pressure) was all that would be needed to trigger movements of bass, that would be sweet.  As of now, no one has found it probably because it doesn't exist. So many variables play into a fish's movements that barometer  may not be that important.  It's a meteorlogical fact that every change in pressure creates wind that blows from high to low pressure areas.  The faster the rise or fall, the greater the winds blow. Cold fronts bring heavy air and the air pressure rises accordingly.  Dry, cool weather  follows with NW winds.

Low pressure is lighter air which causes a drop in air pressure. Typically, clouds and rain with muggy conditions occur. In low light bass are better equipped to chase down or ambush prey.

But it's never as simple as reading a magic barometric number that will trigger a fish movement. How much air pressure affects bass is hotly debated, and I wish I had 40 years of tabulations to give you a more precise answer.

I think high pressure in spring in the lower Midwest really affects fish because of the cooling effect high pressure days have on the water temps. Spring surface temps can fall several degrees during the passage of a spring cold front which brings higher pressure.  When the temps begin to cool in spring, the NW winds blow, the skies clear, the fishing gets tough.  Did high pressure cause the fish to stop biting or was it a drop in temps, the clearing skies, and a change in wind direction?

High pressure in fall doesn't have that same drastic effect on bass since the cooling of the surface layer is a much slower process. I think the barometer is tied to other more important phenomena that positions fish.

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Thanx Nick

i started to type the long answer and i had to leave and didn't have time to write in more detail so i typed the short answer lol.

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Well guys, I asked this question because I heard or read somewhere that high pressure affected a bass's ability to be stable in shallow water.. Has anyone else heard or read this?  Paul

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Yes, a pretty definitive book written several years ago documents bass behavior as observed through underwater photography by an avid angler and scuba diver. Man, I wish I had the book's name and author, but the author may have been Underwood.  He published quite a thick book denoting all sorts of bass behavior as seen through his 100's of hours of watching them.

In summary, he claimed to have seen large bass, after the passage of a cold front, actually tilt their bodies away from vertical and lay rather dormant in and around cover such as weed beds and brush. Now, I have a new mission, and that's to find the name of this book, so you too can read it. Anyone else familiar with it?

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Its funny that you mentioned that book because a few years ago i read the same book.  I can't remember the name of it either but it was great reading. I think i got bored and checked it out at the library it turned out to be a great book. It just kinda showed a different view of things from his observations diving. If i got time tomorrow i'll look it up.

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I checked into it.  It may be called Lunker by Bob Underwood.  Anyway. I requested it from the library. It was written in '75.

Two other oldies to recommend are Bass Wars by Price and Lucas on Bass Fishing by Jason Lucas.

Lucas' book was written from his experiences fishing from the "seat of his pants" mostly in natural lakes in the upper midwest mostly in the '50's.

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Well im glad you found it all i could find was Lamar Underwood bass fishing almanac and they didn't have it in. But i tried.

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I'm going smallmouth fishing tomorrow before the storm hits. The barometer should be falling all day, but my make or break deal on the river in winter is clarity. I actually want the river up and murky.  Go figure that in 43 degree water. I'll catch them on the old black maribou jig if I get clouds because the river has returned to normal with its crystal clear algaeless winter look.  We will have about six to eight feet visibility, and that is tough when the avg depth is only about 6 feet. Funny, even in the clearest of water, that little black jig outshines all others.

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Let me explain it like this. Under stable weather conditions a bass that lives in shallow water will be sitting beside a given form of cover and would be active. Under stable conditions the strike zone will be large and the fish will be willing to chase baitfish down at a greater distance. When a cold front hits that fish will now be in the middle of the given form of cover mainly inactive. The strike zone has now become small and the fish is less likly to chase down a offering. Most of the time the fish will try to find the heaviest form of cover available. Deeper fish under a cold front might move out deeper or suspend. Durring a cold front a smaller offering works better because the bass feels like it doesn't need to work as hard to catch it. There are some cold fronts that have less effect on the bass but most of the severe ones do change the fish's postions and the fish tend to turn down larger offerings.

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I am not convinced that the actual barometric changes affect the bass.  I think the accompanying changes to their environment brought about by cold fronts is the key deal.  Yes, fishing gets tougher usually right after the passage of a cold front.  No doubt fish dig deeper into cover with the clear skies.  They hunker down in the cover under bright conditions for protection and to get an ambush spot. Weeds and brush provide that concealment under sunny skies.  A smaller strike zone may be the result of a bass that fed heavily before the passage of the front and is no longer in need of food. I think the wind change that accompanies cold fronts also repositions the food sources, and the predators have to adjust often moving to a diffferent location to forage. I also believe that bass feed as a response to their environmental changes as nature's way to guard against starvation.  

A great case can be made fishing streams. When a rain causes the water to begin to rise and get dingier, the bass feed heavily.  More food is  washed in which I think gets the whole food chain stirred up, but also with the darkening, soon to be muddy waters, bass feed heavily.  Could they somehow be programmed to know that catching prey will be more difficult under muddy conditions? I'll guarantee you that it is almost impossible to have  bass on the prowl in newly flooded, rushing river.  They hole up and save their energy until the time is again right to feed. Unless one can find a good spring hole with clearer and perhaps warmer water, forget it!

Again, keep in mind that spring cold fronts affect bass more adversely because the thin layer of warm water resting on the surface gets cooled quickly really messing up the pre-spawn and even spawning bass.  Nothing like a good cold front to make bass begin an exodus away from their beds! I just think of all the changes that a sharply rising barometer brings to their world that puts these fish in a negative or inactive mood rather than them being guided solely by more densely packed molecules of air.

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Well I wasn't going to post this, but Nick brought up some interesting points. This is a fairly lenghty write up that I have from another forum on the same topic. Granted this is wrote up more for lake/resevoir fishing ratherthan river or stream fishing.

Why do bass bury up in cover after a frontal system passes? This one make take a while to explain. IMO the reason that bass bury in cover after a front passes is to conserve energy. They have learned thru past experience that catching prey in bright sunny conditions is hard for them to accomplish. They are more easily spotted by their intended prey at this time. Not to mention, bass are in cover to ambush prey even when it is low light conditions.

Why do bass gorge as a frontal system passes through? IMO Thru their own experince they have learned that catching their prey is going to be harder once the system has moved through. Do they realize that it is a front? Not in the way humans do, but I do believe that there swim bladder is sensitive enough to their enviroment to let them know something is changing.

Does the front have a effect on the bass itself? IMO, if it was a bass that was in shallow water, yes. Deeper water, no. Here is where my opion gets really different from most people here in the forum. I think that the air after the front passes, although more dense is actually lighter. Now don't go thinking I'm crazy yet, here me out. When a front comes in the air is not as dense, but it is filled with moisture/humidity. After the front passes through the air looses the majoirty of the humidty in the air. Water weighs more than air hence my theory on the air being heavier before the front passes. This would also explain how a basses swim bladder could become extended after a frontal passing. If the air were heavier, would the swim bladder not become compressed instead of extended? Less humidity in the air also allows more light penetration as well.

IMO the most effects of a frontal system passing is going to be on the bottom of the food chain. The plankton and other micro-organisms that the filter feeders eat take the brunt of the effect. The sudden change in the water temp on the sirface where they mostly live, could very well either kill off some of them or simply cause them to stop doing what they do. So that being said, shad may be mindless little fish that only think of how and when to eat, but I think they know when their food source is going to be disrupted. In turn this cause them to go on the binge. Going on the binge also causes them to be out more in the open for a bass to take advantage of an easy meal.I feel that nature has allowed the bass to know that his food source is soon to be harder to catch, so he gorges himself as the front passes through as a result of the shad being more active.

Now back to the first topic. The majority of baitfish after a front passes are hiding. They are not out swimming in the main creek or river channel. Why? If they were they would be way to easy fo a hungry predator fish to spot them and eat them. They are buried up in the the brush and cover hiding from predators. Sure they can also get some nutrients from the algae growng on the rocks or other cover as well. This is also my opion as to why bass are in the cover after a front passes. They know that this will be their best chance of finding food untill the eco-system gets back in gear. Why do shad move daily to the shallows? To eat mostly. They come in the shallows in the evening to eat the micros that have been blown onto those banks or brought in to the water by wave action during the day. They also use this as a hiding place because there is more stuff to hide around in shallow water than in open water. Come morning they simply pull out of the shallows and form back into their tight schools and surface feed on whatever micros they can find. By them staying in there big schools they are actually harder for a predator to catch than when in smaller groups. It is harder to key in on one fish that way.

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Ernel, air that is more dense must be heavier, not lighter. In lower pressure and warmer air, there is more room between air molecules to allow water vapor to increase.  Water vapor floats as in a cloud.  The sticky air may feel heavy to you and me, but it will not make a barometer rise. It will lower the reading.  

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Nick I agree to a point. However, moisture doesn't always float. If you have 100% humidity, then the vapor is also at ground level. The weight of the moisture has to go somewhere, and be accounted for.

Example:

You have an empty glass box that weighs exactly 1.0 lbs.

Now place a hummingbird that weighs 2.0 oz. in the box and let it hover in place with out touching any of the sides top or bottom.

How much will the box weigh?

Answer:1lb 2oz.

Because the humminbird is occupying the air inside the box, it's weight/mass must be accounted for also.

I know that a humminbird is not water, but it does float like water vapor when hovering in place.

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