Does Barometric Pressure Affect Fishing? you Decide

By: Craig Mumby

Does barometric pressure affect fishing? You decide...

By Craig Mumby

One of the biggest questions these days is whether or not barometric pressure has any affect on fishing. This is widely debated among anglers and scientists, but is there any conclusive evidence?

Barometric pressure is a measure of atmospheric pressure. In essence it's the measure of the weight of the air pressure in the atmosphere. It is more commonly referred to as barometric pressure because the instrument used to measure it is called a barometer. Normal atmospheric pressure is 14.7 pounds per square inch (psi), or 29.92 inches on the barometric scale and spans usually from just under 28 (inches) in extremely bad, low pressure weather to just under 31 inches in high pressure situations. Air pressure is caused by gravity which pulls at the air just as it does with everything else. Barometric pressure changes due to weather systems moving in and out of an area. A very high pressure system usually brings with it clear skies and generally nicer conditions. Very low pressure systems are the opposite usually bringing precipitation and more unfavourable conditions.

There are many arguments either way by some very respectable anglers and scientists. How are we supposed to know what to believe? It seems to me, in pretty much all instances, that it's the scientist that supports the fact that there is no strong influence in regards to barometric pressure and fishing. Most professional anglers on the other hand have something else to say about that entirely. I'm not saying that these scientists aren't avid anglers, or even professional anglers themselves, but nearly everyone I've spoke with was adamant. Some fishermen even go so far as to stay at home if the conditions aren't favourable. I honestly can't say one way or the other which is correct, but to me this is a little excessive. If I have a chance to hit the water; I'm there - whether the fishing forecast is good, or bad. Normally, I would tend to slightly favour the angler over scientist. I say this because there are certainly a greater number of anglers out there everyday compared to scientists studying barometric pressure and it's affect on fishing.

One of the best pieces of advice I ever got was to keep a journal. Now, this isn't going to be a habit for everybody, but if you really want to get answers to a lot of your questions you can just look back at your old entries and compare similar conditions to what you are facing that day. I keep a meticulous journal with the obvious stuff like what I was using, how deep, tides (if you're in the salt chuck), time of day you hooked up, location, etc. Barometric pressure trends for the time that I caught the fish are also something I started to include a couple years ago. My findings side more with the angler, but I'm not one to make presumptions on other peoples successes as I haven't found many people that have as detailed a journal as I do, so there isn't much to study. I urge you to do your own journal and make your own conclusions. As a matter of fact, I'd like very much to hear about your findings.

Do not let this issue affect your fishing trips. One of the silliest things I've ever heard was a gentleman not going fishing because the air pressure wasn't favourable. There are exceptions to almost everything that makes sense in fishing. And if you're not going fishing because the atmospheric pressure isn't what you'd hoped it would be, you could be missing some incredible fishing. And you're also an idiot. I always say that fishing is very much a percentage game and you have to play the odds just as you would in blackjack. The phrase "chances are" should be on repeat in every fisherman's head when it's slow, but the odd time you'll catch a fish and wonder what that fish was thinking. So even if the barometric pressure isn't favourable get out there and enjoy a day on the water because you never know.

Some scientists argue that there is little to no affect on the fish when there is a pressure change. Though my experience has proven otherwise these authors are in fact very smart people and they make some very persuasive arguments. These arguments are what spawned this article because they are somewhat contrary to my own trials.

Their argument is essentially that barometric pressure along with the accompanying weather can have an affect on fish, but if there was a choice between the barometric pressure and weather, weather would prevail as the most likely cause of a change in behaviour.

Underwater there are similar pressures to what we deal with above ground. This is hydrostatic pressure and it is much more intense than air pressure due to water being considerably denser that air. So, if a fish say changes its depth even 5 feet up or down it will go through more of a pressure change, in seconds, than any of us will ever experience on dry land. How could the barometric pressure above the surface affect a fish that goes through equal to a surface pressure change if they move only a few inches up, or down in the water column? Good question, I say. Especially when barometric pressure takes time to affect the hydrostatic pressure; depending on the size of the body of water. In the ocean, for example, it could take approximately a full day depending on the pressure fluctuation.

Personally, my slowest days of production were during low pressure systems and horrible weather. Now, I'm sure many of us have all suffered through some tough weather, but I fish out of the Queen Charlotte Islands in British Columbia, only 50km from Alaska and believe me it gets nasty. So, when you factor in all the elements that generally come with a low pressure system such as rain, wind, rough water, etc. it could be that I wasn't fishing as effectively as I would normally and this is why my production is lacking. But is it the low pressure, or the weather? Does it matter? Boat control is made much more difficult if you're trolling, or trying to stay on one spot. If you're casting around distance and accuracy will certainly be handicapped.

From my findings, stable pressure, fairly close to the norm of 29 - 30.40 inches has been the most productive and generally whenever there is some consistency. Strangely, my best days this year in terms of production was during high pressure systems. It was great. Once the nice weather came in, the fishing got much more enjoyable both in production and comfort. Why, I don't know. Could also be that I feel more motivated to do all the little things when I'm not frustrated by miserable weather. When it's nasty you just want to sit down and not move for fear of opening a crack in your rain gear, so you neglect those little things. And that will cost you, no question. Always stay positive.

Popular opinion among anglers is that fish are more active when pressure is steady, or slightly fluctuating. Over the years of my record keeping I would agree that I have consistently done well on such days. When the pressure starts falling from the norm is most widely regarded among anglers as the best time to fish. Aside from this bizarre year, I would agree. But there is one undeniable fact in my records and that is when there is a more powerful low coming through my production decreases dramatically. But is it the pressure or that bad weather spawns bad habits?

Being on the water for at least 6 months of every year has left me a lot time to think about how to make myself a better angler. The simple answer is knowledge. The more you know about the species, the body of water, different techniques, and of course, weather will put more fish in your boat. There can always be a 2 year old at the end of a dock somewhere with some string and a branch that will catch more, or bigger, fish than you, but the more you know the less you need luck on your side. The effects of barometric pressure will always be up for debate among anglers and one thing I can tell you is that there will never be anything set in stone when it comes to fishing. I have no idea why hot, sunny days were the best for me this year, but I will certainly be more confident heading out on high pressure days because I now have a history of being successful in such conditions. I have a record that shows it. Keep a journal and maybe you can figure out for yourself what the behaviour patterns are in your home waters. I guarantee you'll be surprised at all the information you accumulate and how it improves your fishing dramatically. In my opinion, I believe the biologists are probably right in terms of the trivial affect of barometric pressure on fish in general, but from my experience it's very hard to say whether that is true when it comes to catching fish.

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