Effects on fish feeding and barometric pressure

George Forster · #1

I have just returned from from a period of saltwater FF also a couple of small private casting clinic'sin S.E. Queensland. Hervey Bay and Bunderberg had not had bad weather for several months, but they have now. Thunder and lightning coupled with periods of very heavy rain.
My hosts were from opposing tackle stores although you wouldn't have known as they all are dead keen on salt and fresh water fly fishing and they all get along. they want to cast better, they'er Aussie's.

When I arrived the news was not good. The proffessional fisherman hadn't been out side for nearly three weeks and no one knew of any Barra being caught in Lake Monduran, a large impoundment west of Bundaberg in any fishing method.

A low pressure was and possibly still is stuck right across the top of Australia and beyond (4000k to 6000k) and another caught between our east coast and New Zealand. The winds that go with that low have made the water slighty unclear in places and fishing was poor to say the least.

I'm not sure how it works in other parts of the world but does changes in barometic pressure turn fish on and off from feeding.

George Forster

Paul Arden · #2

Absolutely. I've seen trout switched on by a drop in pressure in Canterbury and yet switched off by it in Southland. In the UK I've only ever seen them switched on. Mind you a better explanation might be that their prey changes behaviour - for example hatches! But that doesn't explain seeing fish laying doggo on the Mataura before a heavy rain front.

Cheers Paul

George Forster · #3

Question is why, salt and freshwater were non productive.

Paul Arden · #4

I don't have enough experience in the salt to have any conclusions regards barometric pressure. Did you try imagining that the weather was better?

Cheers, Paul

George Forster · #5

I didn't, another guy did. I heard him mention something about seeing an imaginary mermaid and we still havent found him.

I'll keep looking for an answer but i need to understand why say trout often close down when the barometer has been low for a while as I have been asked this question many times. I have read a lot of other info suggesting intestinal bladder expansion ect but I'm just not completly convinced.
George

Sudesh Pursad · #6

Hello George...

The short answer is that the Baro pressure is hugely significant on fish feeding behaviour. I watch my Baro constantly when fishing (salt and fresh). The Baro on my watch updates every 30mins, and as little as a 1HPA pressure change up or down has an effect on the fishing. Well, this is my experience in South Africa and some of the tropics that I have fished.

In the salt, when the pressure drops, the fish get into a feeding frenzy. A rising Baro means very slow fishing. Just by using the Baro, I manage my own expectations in terms of my catch rate, as well as my tactics.

In the fresh, I also use the Baro to manage my expectations. More importantly, I change tactics when the pressure drops as the fishing becomes very slow and the fish are reluctant to chase down a super fast swimming lure. I then resort to #14's and #16's buzzers and other small flies. When the pressure is up and stable, then the big lures come out (Woolly Buggers, Frogs, tadpoles, etc), fished on a super fast retrieve.

I believe that apart from the Baro pressure having an effect on the fish, the Baro pressure also affects the wind direction, which in turn affects the water temperature. Without a Baro and just by observing the weather pattern, cloud formations and wind direction, I have a reasonable idea of what the pressure and water temperature is. This then translates into the appropriate tactics to deliver the results.

Long story, but in short the Baro has a huge impact on the fishing. The good news is that you can still be successful even when the conditions are not right.

Tight lines always.

Regards
Sudesh

George Forster · #7

Thanks Sudesh. Do you know what the changes in Baro pressue actually does to the fish anatomicly.
Regards Geogre

George Forster · #8

Here a a couple of good articles on what I was referring to

http://midcurrent.com/science/the-pressure-myth/

http://www.nc-flyfishing.com/effects-of ... c-pressure

George

Paul Arden · #9

Hmmm, two conflicting articles!

Anyway, I was thinking about this a couple of days ago George, and I don't know if they're actually directly affected by the pressure. As humans we always look for physical links - barometric pressure and the swim bladder for example. I don't think it's as simple of that. Before a big storm, all of nature is tuned in. From insects to birds, to animals, to fish. Are they all feeling the change in barometric pressure? Or maybe they're all just interlinked in some way to the part of the world from where it's coming. Could be lots of things.

I think we can make predictions according to these changes of course. What surprises me is how the same species of trout can behave differently just before a spate! Looking forward to getting to NZ!

Cheers, Paul

Toastedheretic · #10

Another angle on the barometric effects on fish behaviour might be dissolved O2, Gas saturation being directly related to pressure. Reg Rhygini did some work on the subject in 'Salmon Taking Times.'

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