Ideal Pressure (QNH)

[PDV]

I think both Robs have a point - there was this company in Cape Town that had a web site where you could see a graph of barometric pressure over a period of time - 3 and 5 day perioda. Unfortunately this site is not operational any more. This could be quite handy to see what the pressure is doing over a period of time.

[robdog]

I think all fish prefer stable conditions and a high pressure seems to help diffuse more oxygen into the water with a resulting increase in fish metabolism

[PDV]

The question of barometric pressure still puzzles me – last weekend we fished Clanwilliam and only got 6 fish over a 1½ day period. Weather was lovely, quite hot – 33C and water between 20 – 25 C. But the fish had lock jaw. The only reason we could think of was that the pressure was falling rapidly.

In Paarl guys had the same experience – very little fish and also there, pressure was dropping.

At Kwaggas reports were that fishing was slow at first but then the guys caught some fish eventually. Not sure what the pressure was doing there?

So, it seems that drop in barometric pressure does have an influence on the fishies??

:blue-rolleyes:

[CrankbaitCarl]

Many moons ago we had an irrigation concrete dam 30 m x 10 m x 1.5 m deep. The water was clear and visibility was right down to the bottom. There were about 20 largies in the dam, a few rats and the rest 1.5- 3 kg.

I studied their behaviour under all weather conditions. We netted vlei kurpers from time to time to feed them, and also practiced with all types of lures.

Firstly I build some rocky structures for the bass to inhabit and then closely monitored their behaviour in different temperature and pressure situations. After about 3 years I came to the following conclusion which I still practice on the water today during bad conditions.

1. If the bass in the irrigation dam starts taking lures on a specific day, the fish in the nearby dams also went on the bite.

2. When the pressure reached 1020 hPa and above, and stayed for a few days, the bass went into hiding. The same happened when the pressure dropped below 1010 hPa.

3. My belief was that they now have lockjaw, but I was wrong. Holding life bait on a dropshot rig with heavy sinker (we did not call it dropshot those days) near the opening
of the structure I got hit 80% of the time. Leaving a plastic hanging at the same opening
I very rarely got a hit.

4. My next exercise (under the abovementioned conditions) was to drop a sluggo (no Senkos those days) right at the opening on the floor. Sometimes I had a strike from inside the structure while dead sticking. Most of the hits occurred when the lure was
twitched slightly after dead sticking. Still only about 20% successes.

5. I then opened the structure on the top so I could drop a lure down the middle without being spotted by the bass. The strike rate increased dramatically, I therefore conclude
that bass will strike if the lute is close enough and alluring enough. These tests were done on different structures in our dam where different bass were laying up.

6. If after a high press system for a few days the press starts dropping, the bass exited the structure and started feeding.

7. If after a low pressure system the pressure starts rising the bass exited the structure ONLY on the second or third day.

These observations helped me a lot as it was firsthand experience. I now take as many as possible close-up photos of structures while the dams are low. When similar conditions prevail I fish these structures differently than normal. I believe bass will always feed (eat) if the presentation is natural and it does not have to exert itself to catch it. I must mention that we replaced the bass regularly, because they got used to our pattern. I still don’t know what the barometric pressure does to the bass, but I know how they behave.

Hope you find this informative.

[Guest]

What a great bit of info, been a long time since we've had something really useful on the site.
Nicely done 'CrankyCarl'. :blue-biggrin:

[PDV]

I agree, that is really some useful info - thanks Carl!

:blue-badgrin:

[robdog]

That is very enlightening, thanks. I often check the barometric pressure but never really knew what effect it had :blue-cool:

[pomerob]

Thats easy rob, blood pressure goes up then it is time to go fushing.

[robdog]

Rob, I go fishiong at every opportunity and the barometer is incidental :blue-lol: