under pressure, the heat is on

[kingiemaster]

Under pressure...

Like many of you I’ve read and heard firsthand about barometric pressure and it's effect on fish and fishing. Rising barometer turns the fish on, steady barometer or high barometer keeps them biting, a falling barometer turns them on whilst a low or already falling barometer turns them right off.

Unlike the myth that apps run in the background on your iPhone and drain your battery there must be some truth to it or people wouldn't go on about it all the time, especially when it comes to Bass, Barra and Jewfish.

A little Summer bass

Thing is I really don’t have any evidence of this or indeed evidence that barometer reflects the weather at the time.

One Sunday Back in Feb 2011 the Kingfishing in the harbour was red hot. We had a very hot night (I slept on the boat) followed by a very hot and humid morning ahead of a Southerly change in the afternoon. That morning I lost a very big Kingfish at the wedding cake after a five minute battle. I’ll never know how big but I’m sure it would have been the biggest I’ve ever connected to. I also caught rats and lost another good fish. Other boats were catching fish as well. One boat in particular seemed to be doing a lot of yahooing. Later at the ramp I saw what the yahooing was all about. It was Cephalopod with two big fat kings over a metre with bellies full of yakka’s and some cuttlefish. Ceph said he knew it was going to be a good morning with a falling barometer ahead of the change. I eagerly nodded in agreement, “yes , yes, it was ahead of the change that got them firing”. It all made sense.

But I never really followed this up to confirm so I’ll never know what the barometer was really doing that day without delving in to the bowel’s of BOM.

What’s made me think twice is that I have been following barometer movements more closely since. With few exceptions the barometer readings never reflect what I expected. Last week is a perfect example. On Friday the barometer was quite low most of the morning despite the hot dry Westerlies and the temp heading towards all time records. Admittedly the barometer dipped abruptly and briefly on the change, only to RISE as the southerly and wet weather settled in for the weekend. It then stayed high at over 1015 all weekend. I would have expected the complete opposite. High, sudden drop and then steady low over the weekend. Yesterday the barometer fell as the weather cleared!

Presumably fish can only gauge or sense barometric pressure in their immediate vicinity and therefore can only detect immediate changes ie falling or rising barometer.
And as far as I know fish don’t read the paper, watch TV or have access to the internet. So presumably they cannot predict or forecast weather as such, only that it might be about to change, or indeed has changed, and behave accordingly (ie feed or stop feeding). But if I am right and local barometric pressure does not necessarily relate to the actual weather then how does the weather really impact fish feeding behavior? If at ALL! And how do you use the barometer if it does?

Lets put it this way. If you only had an hour to two to fish last Friday when would you have fished? Based on the barometer readings for the day it would have been very very difficult to have picked the two hours before that sudden and brief barometer change.

In fact I sometimes wonder, from my own experience of keeping relatively consistent, accurate and complete fishing diaries of the past 5 or 6 years, whether water temperature, moon phases, weather and barometric pressure really impact fish feeding behavior as much we like to think. Is it just a great way of making excuses for not catching fish? "everything was perfect but the barometer just kept going down", or a way of talking yourself up when you do ? "yes, yes I planned this, picked my tides, tied me knots, got me bait, water temp was 19.56, twas three days before the full, cast me lines in, waited and then I read the barometer and saw it was about to fall and then zzzzz the port rod went off "

The heat is on.....
Of course tropical currents and temperature breaks in gamefishing makes sense and are well proven. As are water temperature ranges or changes triggering the breeding of many species of fish, trout being the most well documented. And my Rainbow fish always got frisky when the temp rose, and during lightening incidentally.

But do Kingfish really care what the water temp is? We catch them all year around after all. They might prefer it to be 20 degrees but it doesn’t kill them if its 14 degrees. Yet so many people carry on about it like it’s all that matters eg “can’t wait for the water temp to rise for the Kings to turn up/turn on” without any real justification other than that they’re not catching any. I dont think its the Kings following the warm water necessarily. Schools of summer Kings probably just follow the food. If the food likes the warmer water (eg Whitebait, Slimies, Bonito) then the Kings won’t be far behind.

Slimies from the belly of a Summer king.

Longtime Kingie legend, Kelvin, recently posted a report of Kings he had caught over the past year and wrote that in the depths of Winter when the water temp is low they seem to be a less aggressive, and more lethargic once hooked, BUT that he still catches them YEAR ROUND!!! Keep thinking what you like about water temp and Kingfish, I'm just saying maybe you should just get out there when you can not worry too much about the water temp and focus on getting out there early and catching bait and trying all the likely spots. In any event it's not like you're not going to fish spot A over spot B because of a 2 degree temp variation is it?

A mid winter King from Middle Harbour. Water temp wouldn't have been more than 15 degrees.

Tides on the other hand do seem to play big role, at least in any river, lake, estuary situation. The most obvious being you need water over a sand flat before you can fish it.

Back to the barometer. Any weather experts out they care to shed light on why barometric pressure doesn’t appear to reflect the actual weather? I am missing something? Any biologist that can explain how fish detect changes in the weather through barometric pressure, especially as they are under water and not on the waters surface . Is barometric pressure different underwater?

Cheers

Dave

[Scratchie]

Wow.....I'm in to fishing but you are on a whole new level. I'm still checking tides and collecting bait. But it is another excuse I can use and made for great reading!

Cheers scratchie!!!

[Hodgey]

A great topic Dave and one that should generate a fair bit of interest.

I have always been under the impression that baromentric change is most significant when fishing in fresh or shallow water, which is of particular interest to me as these are the two areas I fish the most. It seems the deeper water negates the effect of the barometer due to its own pressure?

I had a prolonged discussion with a local freshwater guide recently and he was adamant that it effected fish feeding habits to the point that he purchased a watch online specifically because it shows barometric pressure. Some smartphones have a barometer app that local fishos claim to be quite accurate as well. (I must look into which one it is and download it myself!)

A search on Google has produced some very interesting articles regarding the effect of barometric pressure on fish habits/fishing but I have yet to discover how fish detect changes in the weather through barometric pressure. I would imagine it would have something to do with the lateral line? I guess I need to investigate further and look forward to other members' responses.

Cheers

Hodgey

[kingiemaster]

Ok so I did some more research, which I probably should have done before I posted, but hey its nice to shoot from the hip sometimes. .
The general uninformed/unproven consensus is that fish feel the effects of the pressure through the swim bladders which in turn effects their behavior but water pressure changes dramatically with every foot of depth negating this.

That’s when I came across an article, which coincidently shares the same title as mine, ‘under pressure’, by no no no which starts off along the same lines as mine debunking the belief that barometric pressure has an effect on fish and fishing. However, his has far more science and goes onto theorise that crap weather results in murky water and ultimately lower oxygen levels, especially in fresh water as plants photosynthesise less, whilst in saltwater foul weather stirs up low oxygenated cold currents. Much of this makes sense.

But its’ far from conclusive.

Despite the science in the article his theory still contradicts some common science around oxygen levels namely that hot temperatures, especially in fish tanks, reduces oxygen levels, not increases it. So why would you look for the warmer water were oxygen levels are likely to be lower in a low barometric/poor weather day?

I also found a lot varying opinions from around the world about when it is good or bad to fish depending on the barometer including falling barometer no good (Rex Hunt) whilst others say it’s the BEST time to fish.

After some further digging I found a range of possible explanations as to why weather, not so much the barometer, effect different species of fish in different ways.

In conclusion, whatever the real science is, I think weather plays a bigger role in fish behavior than the actual barometric pressure itself, for any number of reasons.
Simplistically you could rely on the following
- Falling barometer/low/storm from any direction/southerly change approaching COULD be a really good time to fish. Or at least it wouldn’t hurt to go out and give it a go if you can but don’t get it wrong and get caught in the storm!!!
- High barometer ?? Might play a role in higher water temps (too high) and therefore lower oxygen levels. But if the weathers nice why not just go for a fish in morning before gets too hot and then go for swim afterwards. Nothing to lose.
- If the weather is plain awful, whether the barometer is low/med/high, whatever, do you really want go fishing anyway?
- Rising barometer/low retreating/weather improving etc COULD be a good time to fish as they come back on the bite. Also a nice time to fish. So once again nothing to lose.

So I’m not about to follow the barometric pressure online nor buy a barometer as I think by the time the barometer falls it’s probably too late. I will however consider going for a fish, or indeed step it up a gear if I’m already out there, for Kings or Jews or bass if there is an impending southerly change or storm front coming from the west etc.