Barometric pressure changes - do they really matter?

[DerekD]

Hi all,

The following is an academic discussion as I am not sure how to scientifically follow up on it.

Over the years, seeing advice on fishing from multiple sources, I have developed a peeve on a few particular topics.

The first is all this advice on fishing the top or bottom of the tide. The way many people seem to interpret the advice is that the whole harbour will magically switch on as soon as high or low tide comes around. I wish it were that simple. It is not that tides don’t make a difference but I get the feeling they often don’t look at the why in a particular area. High tide might give better access, low tide might flush out food, back eddies may trap bait fish, dead flow minimises swimming effort when searching for food, etc. There are competition bream fishos that are phenomenal at judging the cause and effect of the tides when chasing this wily species.

My other peeve (and the reason for this post) is barometric pressure – rising or falling. I hear people talking about pressure changes suddenly turning on the fish. Now I get this might actually be applicable to fresh water fish (more on that later) but I struggle to see how it applies to saltwater fishing. Let us look at the two biggest recorded extremes in air pressure at sea level as per current font of all knowledge Wikipedia https://en.wikipedia.org/wiki/Atmospheric_pressure

The highest mean level sea level pressure recorded was 1085 mbar in Siberia. The lowest measurable sea-level pressure is found at the centres of tropical cyclones or tornadoes with a record low of 870 mbar.

Now let us convert these into metres of water column to get a relatable measurement. 1085 mbar = 11.063 m of water. 870 mbar = 8.871m. The difference between the two being 2.192m of water column.

I forget where I found it but the pressure range at sea level normally fluctuates between 1050 mbar (10.707 mH2O) and 950 mbar (9.687 mH2O). In this case under normal atmospheric conditions we can see a pressure difference of 1.02m of water column between the two extremes.

I am ignoring the fact that sea water is denser than fresh water because we are talking relative pressure changes and it should cancel out. So in our harbour the maximum barometric pressure change a fish should be subjected to is 1m of water column. Compare this to the tides which will generally fluctuate every 6 hours say a minimum 0.6m and more often more than 1m. On the 20^th of February 2019 there is a forecast high tide of 2.04m and the low after is 0.10m. This is a difference of 1.94m which is close to the absolute extremes of barometric pressure which can be experienced at sea level.

I like chasing kings and have often (never often enough) seen them racing up from the depths to have a look at a lure or bait. In other words they will change through more than 1m of water column at the snap of a finger. Bream and a lot of other species will move through the water column as they feed. They are both subjected to tidal variations of greater than the equivalent barometric pressure changes. I am not saying that the animals on this planet are not aware of subtle nuances in atmospheric conditions. Bats can pick out small insects using acoustics. Pigeons can pick the magnetic fields of the earth. What I do question is how salt water fish out on the ocean or in the harbours can make the distinction between these relatively slow barometric changes from the more extreme tidal changes and their natural movement through the water column while they feed.

I do believe it could be feasible for freshwater fish as the level of water in a stream is far less likely to fluctuate. This means they have a chance to pick the changes in atmospheric pressure but the question is now how quickly and how extremely would these changes have to occur for them to be able to sense it? I’ve suffered from a bleeding nose before due to pressure changes while flying or even driving down a mountain but these events were relatively quick. If they had taken 3 or more hours I don’t think I would have noticed it or at least not suffered.

Just my thoughts.

Regards,

Derek

[JonD]

I remember a magazine doing an article over around eight pages of collected data confirming the influence pressure changes influenceing different fish species hunting habits. It could of been the F&B magazine which is no longer in production, I did have a copy which I may well still have somewhere. At the time I was extremely interested in mullaway facts, which led me to a small electronic almanac device which gave peak periods for many different species, including increased or decreased catch rates depending on the pressure rising or falling.

The very first time I used this to target Jews from a Sydney beach it stated peak time for jews was between 8pm to 9-15pm. I started fishing at my usual 6pm ish after making my way to the beach after work, at 8.10pm I hooked into my first jew of 23 kg. From then on I had many successful mullaway sessions all within the almanacs peak times and all on a falling barometric pressure.

 

[Volitan]

I’m in the ‘it makes no difference group’. 

I reckon I’ve proved it to my own satisfaction over many years. 

incidently, I’ve always thought this was a myth that got its start many years ago, when the genteel people chased salmon and trout and it was the only game worth talking about. The belief was that fish could tell when a storm was coming and they fed well beforehand. Rapidly falling barometer meaning possible flood in Europe/ Britain. If you’ve ever looked at a normally placid river in flood - when it’s a raging brown torrent - I’m sure you’ve wondered how the fish survived. The fish were correct, it could be many days before they could feed again. From there it has generalised to all fish in all aquatic environments without a skerrick of empirical evidence or logical explanation.

 

[Belligero]

If there is a storm coming the fish tend to go a bit crazy and I would think the change in pressure is what tells the fish to feed. 

[frankS]

Barometer plays a very big and important part of every day fishing, those electronic fish calculators are based on polynesian history where over the century's they developed a system to help them work out good fishing times V bad fishing times, their very existence  depended on catching fish.

Type in a set day with steady barometer, then type in the same details except change barometer to rising and you will get a different result.

Over many years of using one of those electronic devises, I found them to be a major part of success with my fishing and I learnt much by practice and reading between the lines. They virtually work the moon phases sun rise etc to calculate the results . Haven't used it now for many years but still have it.

Frank

 

[DerekD]

8 minutes ago, Belligero said:

If there is a storm coming the fish tend to go a bit crazy and I would think the change in pressure is what tells the fish to feed. 

Hi Belligero,

Thanks for your input. It is a topic that has been on my mind for years. Just for clarification - how would you define crazy? One of my friends said he had one of his best sessions off the kayak when he was out and the weather turned. In his case it may have been all the pattering of rain on the water which set off the predatory fish (we had a lot of baitfish around at that time).

I came across a nice article about this from a freshwater fisherman and he used the example of the barometer raising  from 1016 mbar to 1018.2 mbar over a five hour period. When I did the numbers this worked out as a change of 6cm of water column. A fish at a stationary level in a stream might feel the difference but in a saltwater environment I wonder. Discussing this topic further with @wazatherfisherman I realised I hadn't factored waves/swell into my discussion. I am impressed that the fishfinder on my kayak can pick the up and down movements of the waves compared to the bottom of the harbour to a 10cm accuracy. Most waves will be bigger than this inside the harbour and then we start talking feet or metres outside the harbour. How would this feel to the fish. Waza pointed out that when the Southerly came through on one of their regular fishing spots that the bite came on. What I also understood from him was there was sometimes related colour change in the water when this wind came through but not always a barometric change.

I'm just wondering if there are other factors which come into play to set off the fish during a storm. For example, the change in ambient light or maybe the thermocline turns over. It might be that smaller baitfish start to react and this then gets telegraphed to the other species in the area.

@wazatherfisherman also related the topic back to mulloway in a way that made sense to me. My experience has been that I usually hook them fishing big baits on the bottom suggesting that they have a tendency staying at one level in the water column. If they are not moving up and down then changes in the water pressure are more likely to be noticed.

Regards,

Derek

[frankS]

One little trick I used to employ outside was get a hose and sprinkle the surface with fine spray which in turn made tiny bubbles and the sprinkling of water made it look like a fish boil and believe it or not it used to bring the Tuna and Kings to the surface. I'll bet Waza had many such tricks.

Frank

[DerekD]

Just now, frankS said:

Barometer plays a very big and important part of every day fishing, those electronic fish calculators are based on polynesian history where over the century's they developed a system to help them work out good fishing times V bad fishing times, their very existence  depended on catching fish.

Hi FrankS,

Not sure how to say this without meaning to sound disrespectful so please take me at face value when I say I am genuinely curious about the Polynesian angle. To my knowledge it the Europeans and probably the Chinese had developed the instrumentation to check the barometric pressure but I wonder how the Polynesians would have done it. I expect they would be watching the weather very carefully but it would take a pretty high degree of sensitivity to detect small pressure changes.

Regards,

Derek

[DerekD]

12 minutes ago, frankS said:

I'll bet Waza had many such tricks.

Frank

Hi again Frank,

I started talking to @wazatherfisherman when Big Neil was coming to Sydney earlier this year and we were planning one of the day's out. Since then I chat to him at least once a week. Due to his limited mobility I think he enjoys hearing about any fishing going on and from my perspective the breadth and depth of knowledge he has is phenominal. Sometimes it is a verification of something I suspected but there are also plenty of gems of information to be learned from him.

Surprisingly there is one thing I have been grateful for because of the the proposed Marine Parks. During the research and discussions I have met some fantastic people and it has really hit home how important fishing is within my life and for my well being.

Regards,

Derek

[Berleyguts]

57 minutes ago, DerekD said:

Hi FrankS,

Not sure how to say this without meaning to sound disrespectful so please take me at face value when I say I am genuinely curious about the Polynesian angle. To my knowledge it the Europeans and probably the Chinese had developed the instrumentation to check the barometric pressure but I wonder how the Polynesians would have done it. I expect they would be watching the weather very carefully but it would take a pretty high degree of sensitivity to detect small pressure changes.

Regards,

Derek

I believe that the Polynesian charts relate to the position of the moon and sun in relation to the earth, not to barometric pressure. Although, barometric pressure may be partially influenced by the moon and sun.???

Apparently, the best times are when the sun and moon are opposite each other. According to the Fishing Calendar app on my phone, right now is a major fishing period in my location, see photo.

However, today is rated at 14% efficiency. If I can get a fishing trip in on a 100% efficiency day, or near enough, I certainly seem to do better.

I have noticed that the fishing is better in these peak periods, especially if they coincide with a tide change and sunrise or sunset. The times also coincide with peak times as shown on my Casio Fiishing watch.

Edited September 28, 2018 by Berleyguts

[Belligero]

Quick google search came up with; https://www.outdoorlife.com/articles/fishing/2010/10/fishing-fronts-how-storms-affect-fishing

[frankS]

Derek. It probably was the Chinese who came up with the electronics of everything, but don't forget The Chinese are the best at copying other peoples ideas and turning them into success.

Frank

[wazatherfisherman]

2 hours ago, DerekD said:

Hi again Frank,

I started talking to @wazatherfisherman when Big Neil was coming to Sydney earlier this year and we were planning one of the day's out. Since then I chat to him at least once a week. Due to his limited mobility I think he enjoys hearing about any fishing going on and from my perspective the breadth and depth of knowledge he has is phenominal. Sometimes it is a verification of something I suspected but there are also plenty of gems of information to be learned from him.

Surprisingly there is one thing I have been grateful for because of the the proposed Marine Parks. During the research and discussions I have met some fantastic people and it has really hit home how important fishing is within my life and for my well being.

Regards,

Derek

Hi Derek and thanks for the kind words. Sorry it's taken me a few days to get back to you on this very interesting and (in my view) important topic.

Belligero has posted a fantastic article on the subject- I couldn't put it in better terms and it goes right along with our conversation re approaching/arriving S/East winds, particularly during summer. It had me nodding my head in relation to the things we were discussing on the phone, particularly Mulloway. I can certainly relate to the lowering pressure being great for Mulloway as they'd 'come-on' regardless of tide/time of day. The ants sure seem to know when storms are on the way!

Having said that though, as Baz and Frank said, the solunar charts that have been used by Polynesians, Maori and many other cultures for centuries. The charts (or whatever their substitute is/was) referred to 'major' periods of activity for life, both in and out of the water. 

Their use, combined with falling barometer, seasonal availability, food abundance and localised factors are all contributing factors to a complex equation that has infinite 'variables'.

Then of course are the times when none of this makes any sense, as the fish are biting in clear water, at low tide on the "wrong" conditions in the middle of the day and on an 'unusual' (not their regular) bait.

Hope we never get all the data right as we'll catch them every time and fishing wouldn't be as interesting! 

Cheers mate and thanks for another interesting and thought provoking article

[wazatherfisherman]

4 hours ago, frankS said:

One little trick I used to employ outside was get a hose and sprinkle the surface with fine spray which in turn made tiny bubbles and the sprinkling of water made it look like a fish boil and believe it or not it used to bring the Tuna and Kings to the surface. I'll bet Waza had many such tricks.

Frank

G'day mate the sprinkler spray is a great and sneaky trick! The greatest fisherman I have ever known was George Forrester of the AFA club, like you, he was always thinking 'outside the box' with great practical ideas. He used to have a whale-oil or tuna oil drip added to his sprinkler set-up. He aimed it so he had a 'patch' about 6-7 metres behind the boat. In a Sydney Metro comp once, he was pulling Trevally and Tailor from his 'patch' one after another while the 60 or 70 boats around him got none! The sounder was blacked out with masses of fish through the area, but the sprinkler had them excited. 

[wazatherfisherman]

3 hours ago, Belligero said:

Quick google search came up with; https://www.outdoorlife.com/articles/fishing/2010/10/fishing-fronts-how-storms-affect-fishing

Thanks for posting the article- it is a fantastic bit of information!

[wazatherfisherman]

4 hours ago, Berleyguts said:

I believe that the Polynesian charts relate to the position of the moon and sun in relation to the earth, not to barometric pressure. Although, barometric pressure may be partially influenced by the moon and sun.???

Apparently, the best times are when the sun and moon are opposite each other. According to the Fishing Calendar app on my phone, right now is a major fishing period in my location, see photo.

However, today is rated at 14% efficiency. If I can get a fishing trip in on a 100% efficiency day, or near enough, I certainly seem to do better.

I have noticed that the fishing is better in these peak periods, especially if they coincide with a tide change and sunrise or sunset. The times also coincide with peak times as shown on my Casio Fiishing watch.

 G'day mate I've also got the watch (2nd one now) and I have great faith in it's accuracy and principles! Love being able to plan things in advance from the wrist!

[Berleyguts]

43 minutes ago, wazatherfisherman said:

 G'day mate I've also got the watch (2nd one now) and I have great faith in it's accuracy and principles! Love being able to plan things in advance from the wrist!

 But it’s annoying when you’re at work and it keeps flashing at you “fish, fish”! ?

i haven’t been able to find another one the same. Only pure digital. I like an analogue watch.

[wazatherfisherman]

6 minutes ago, Berleyguts said:

 But it’s annoying when you’re at work and it keeps flashing at you “fish, fish”! ?

i haven’t been able to find another one the same. Only pure digital. I like an analogue watch.

I searched for ages to get 2nd watch after first broke at joint- watch still works but can't wear it. Kept it as a 'fishing computer' though!

[Fufu]

Could anyone recommend an app or device?

Sounds like some great bit of information to take advantage of

Fufu

[big Neil]

Hi everyone who has contributed to this very interesting topic. I really don't know too much about the impacts, one way or another, in salt water fish responses to Barometric pressure. What I can relate though is the conditions applicable to the absolute best days fishing for Murray Cod. I had fished for several hours of a hot balmy day in Summer and caught about 8 fish. I became aware of a huge black cloud mass working its way up the river, and the breeze picking up. A "typical Summers afternoon storm" starting to develop. It was heading my way and was between me and the boat ramp (several kms away)...so there was no point in packing up. During the next 1.5 hrs I caught 28 Cod... by far the best fishing I had ever encountered. No doubt in my mind that the "front" which worked its way up the river was responsible. This only happened the one time as we don't seem to have the afternoon thunderstorms (in Summer), any more. I also believe that fish are extremely capable of picking up "signals" as they do their thing each day. They can pick up minute movements of bait in pitch black or murky water, can respond to the slightest change in temperature and definitely have "preferred feeding times". Interesting topic and one that I'll enjoy following. Cheers, bn

[wazatherfisherman]

1 hour ago, big Neil said:

Hi everyone who has contributed to this very interesting topic. I really don't know too much about the impacts, one way or another, in salt water fish responses to Barometric pressure. What I can relate though is the conditions applicable to the absolute best days fishing for Murray Cod. I had fished for several hours of a hot balmy day in Summer and caught about 8 fish. I became aware of a huge black cloud mass working its way up the river, and the breeze picking up. A "typical Summers afternoon storm" starting to develop. It was heading my way and was between me and the boat ramp (several kms away)...so there was no point in packing up. During the next 1.5 hrs I caught 28 Cod... by far the best fishing I had ever encountered. No doubt in my mind that the "front" which worked its way up the river was responsible. This only happened the one time as we don't seem to have the afternoon thunderstorms (in Summer), any more. I also believe that fish are extremely capable of picking up "signals" as they do their thing each day. They can pick up minute movements of bait in pitch black or murky water, can respond to the slightest change in temperature and definitely have "preferred feeding times". Interesting topic and one that I'll enjoy following. Cheers, bn

G'day mate that's awesome fishing- fresh or salt! It is an interesting topic. Was telling Derek about the Mulloway action we used to get when the S/east wind started to blow in summer, however I remember reading some well prepared posts on here talking about how the bite 'shut down' when the barometric pressure dropped below a certain point. 

Also remember reading about Mulloway not fully developing their swim bladder until they were over about 6-8 kg, which prevented them rising quickly in the water column, hence why rarely catching them around that size closer to the surface in deeper water. Wonder now how much that has to do with the pressure change Derek highlighted?

[wazatherfisherman]

7 hours ago, Fufu said:

Could anyone recommend an app or device?

Sounds like some great bit of information to take advantage of

Fufu

Hi Fufu the 'device' is a Casio 'Fishing Time' watch, which has tide, moon phase and recommended 'best fishing' times for the day. You just set your latitude and longitude and it comes up with the best fishing time/s for that day. Also can be forwarded to check the information for future trips. At less than $150 a very useful 'tool' but very hard to find one last couple of years. Cheers Waza

[Berleyguts]

13 hours ago, Fufu said:

Could anyone recommend an app or device?

Sounds like some great bit of information to take advantage of

Fufu

There are the Casio Fishing Time watches as Waza says (although I think it’s called Fish En Time). I haven’t found them in stores for some years but they are available on eBay. Also, have a look at the Fishing Calendar app available from the App Store and I assume also available for Android. This app shows the solunar tables and tides and you can also record captures with photos:

[seasponge]

Listening to the guys on the Outdoor & Fishing show, they are always saying that a higher pressure will be better for fishing. The theory being that when the pressure is low, the fish's swim bladder expands and the fish feel bloated and shut down. On higher pressure, the opposite and fish feel hungry. Yet all the talk here seems to be about low pressures turning the fish on. I have a barometer on my wall and when I see big spikes in the pressure, I'm dying to get out and test the theory, but with a 3yr old and a 5 week old baby at home, I can't always drop everything and get out there on a whim. When the 5 wk old was born, there was a huge spike in pressure that lasted for about 5 days. On day 6 I was about to get the kayak out, but on that day, the pressure had dropped back down to normal, and I didn't get a single nibble all day. 

I really don't know what to think. Fishing seems to be a pastime with so many variables - no wonder I haven't cracked the bloody code yet!!

The original post by Derek makes more sense to me (ie, what minute difference is is going to make to saltwater fish swimming in the ocean). 

[Berleyguts]

I lean towards the higher pressure theory, particularly just prior to a low coming through, so, I like a rising barometer just prior to a falling barometer. Just think how often on those muggy days, do the fish go off just prior to the change coming through and you have to make the decision to stick it out and catch fish or make the run for home? ?