High or Low pressure. Good or bad?

Is there any scientific proof that high pressure is bad for fishing?or is it just so much hokus pokus to console us when we cant get the fish to bite. We fished the trent today on known productive pegs in seemingly good conditions and blanked save for a couple of small kamikaze chub as did the six anglers on the same pegs the day before. A period of high pressure could be the cause, Any ideas anyone.

PS. The stretch has also been used for a team of caoeists for several days prior to our visit so that wont have helped.

If Chris Lyons' "Moonstrike" theory is correct, and if I've interpreted it aright, then 4 days before full moon is about as bad as it gets...

Could the temperature drop have more to do with it? It's been far cooler the last couple of days. Pressure and temperature changes do affect the fish but logically correlating them?

If you were asking about winter fishing I could give you some very definate answers! but summer wise Ive never really bothered to look in to it! Possibly though it may be simply down to varying air pressure not having either as much affect in the summer months or the species I target in the summer not being so affected by it.

During the winter months I would say that air pressure definately has an effect.A massive subject,certainly too vast for a post but briefly Ive found pike far more active during periods of high pressure (possibly the period of change to high pressure?)than they are in low.Conversely Ive found carp (and most other cyprinids for that matter)far more active during low pressure conditions.These are that defined that if anyone doubts it I would be more than confident to say come fishing with me over the winter and I will prove it to you! Not many angling things I could say the same about!

The only thing I've noticed at this time of year is that when you get a change in weather after a long settled spell, normally a low pressure frontal system after a period of high pressure, then the Barbel fishing goes off for a day or two. Last Friday (7 July) was a good example.

I'm not impressed with the moon phase theory, but pressure definitely has an effect. As Budgie says its probably the period of change that has most effect.

This has been debated so many times on FM, and it always throws up a welter of differing opinions. So I will stick to my original thoughts until someone can argue scientifically against them!

That is - if the changes in pressure affect fishing, then it can only be as a result of a limited number of things - weather change brought about by differing conditions(preciptation, temperature, sunlight and wind), physical changes within the body of water (ie pressure change) or changes to other part of the ecosystem that in turn impact the fish (which personally I discount).

We know that weather does impact fishing, however my understanding of physics would suggest that changes in barometric pressure will have little, if any, impact within a body of water per se?

So I would say it is as a result of the associated weather changes, and not any physical change of pressure itself.

Mick,

I blanked on opening day on the Trent at Burton Joyce, the river looked in good nick and I was fishing in one of the same few pegs I had good mixed bags from every visit last summer. I realy couldnt believe it, it was totaly dead, never saw a fish top all day and never had so much as a sucked maggot in 6 or 7 hours (god knows why I stayed that long, just couldnt admit defeat I suppose !).

I think I'll be going back for more punishment this thursday but will try further down, maybe Caythorpe,Hoveringham or Fiskerton. I'll let you know how I get on
( join me if your doin nowt?)

Bully,undoubtedly it is the weather conditions that the change in air pressure bring that affects the behaviour of fish.

But be under no misconception that the fish cant detect this change in the pressure.I would even go as far to say that they may be able to actually detect an imenent change in the pressure it self.

I say this as Ive experienced several occaisions when Ive not really given the weather a great deal of thought but on going out have noticed the barometer is low.Whilst out and not expecting to great a day it has suddenly "switched on" and the fish have fed well (once again Im basing this mainly on pike during the winter)Upon packing up and returning home (no great visual sign of classic high pressure weather conditions at this time)Ive checked the barometer and it has only just started to rise.

Ive wrote quite a lot on how air pressure affects weather and how in turn this resulting weather affects different species (mainly broken down simply to prey and predator species)it is a massive and can be quite technical subject.

That said the proof is in the pudding,or this case the fishing.You go out piking regular enough over a space of time in all conditions you cant help to notice definate trends.

As for the affects of the moon? yes I also believe that this affects fish too, despite thinking that most of what Mr Lyons says and writes is fanciful rubbish!

Just been reading the Fishermans Vade Mecam and it says

'Some fisherman find they catch most when the moon is at its last quarter and in the first 5 days of a new moon. This is also the opinions of anglers on the continent'

Alrite so the book is 60 or 70 years old but do you think this has any credibilty?

Not as up on the moons affect as I am air pressure but the one thing I have noticed over the years is how it affects fishing for big bream.On nights where the moon is full (regardless of whether it is visable or obscured the bobbins stay still,not even line bites.Normal nights not only am I catching but the bobbins are dancing all the time with the fish obviously moving.Ive also found the fishing during the day during this period not to be very good (allthough not as drastic a difference) either.I try to avoid big moons for any species.

As it doesnt matter if the moon is visible or obscured I dont think its the light thats the issue.Possibly the moons pull on the earths gravity? after all it affects the tides.And if Im prepared to accept that fish can sense air pressure then why not gravitational variations?

They live in a very different enviroment to us and as such their senses are very different.Ive no proof just that this is the only acceptable reason that I can think of for it affecting the fish.

When I used to eel net comercially we noticed that our catchs would be crap in the same big moon conditions.A book I read re eels by some Japanese guy suggested that they moved higher in the water during these conditions.As I said I dont know......but I dont think Chris Lyons does either as when Ive asked him to explain why his charts "work" he cant/wont and many years ago when I gave him a chance to have one of his charts tested out he declined to.That said there is something to it that would be nice to understand.

I don't think barometric pressure has much effect on fish directly. A fish has only to swim through a depth in the water of a couple of feet and it experiences a far greater change in pressure than on the scale of a barometer.

I think that weather conditions affect temperature and oxygen content of water. There is a optimum temperature of about 14 deg C when O2 diffuses best into water. This is helped by ripples or waves on the water, or by weirs or white water.

The Americans have done a lot of research into the behavior of predatory fish such as large mouth bass. A cold weather front accompanied by lower barometric pressure has the effect of knocking the fish off feed for a period. Why, no-one seems to know. This also seems to affect all predatory fish, especially pike and trout.

On the other hand, cyprinoids such as tench, bream and barbel can be brought right back on the feed during a low pressure front, especially in winter when low pressure often means milder temperatures, overcast skies, more wind and therefore higher O2 content.

" I think that weather conditions affect temperature and oxygen content of water."

And more importantly for predators light levels Ron.

>>I don't think barometric pressure has much effect on fish directly. A fish has only to swim through a depth in the water of a couple of feet and it experiences a far greater change in pressure than on the scale of a barometer.<<

Ron, if you walk into a room with an open fire, you feel the temperature rise but you are not concerned because you are expecting it. If you are sat down minding you?re own business and you feel the temp rise then you are concerned because there is no reason. The pressure sensors along the lateral line of fish are perfectly capable of detecting very slight variations I pressure.
The question we should be asking is why would some fish respond to changes in atmospheric pressure?

Most of you will be familiar with the FM Venue reports and those of the Ribble, 900 plus postings over four seasons. I?ve now popped all these onto one spreadsheet (15.6Megabites) along with river levels (taken every 15 mins for the last four years, curtsy of the EA) moonrise, sunset and sunrise times and also average barometric pressure (however the web site I?ve down loaded this from only goes back 1-1/2 years, they do a hourly range but I?ve not yet downloaded this). It is possible now, for anyone who?s got the time, to analysis catch rates against weather conditions for the Ribble.
I could if I was minded, and had the time, plot for any one of the Ribble sessions the river levels and barometric pressure for 5, 6 or any number of days prior to that session.

But John, Ron's point, as is mine, is that a fish dropping 2 feet in depth will be affected by more pressure change than anything affecting a body of water due to barometric changes....I dont think there is any evidence that they can detect these changes. Changes in barometric pressure make insignificant difference on a body of water, if any. I suspect the moons gravitational effects are greater than barometric.

Thats the key point.

Happy to be proved wrong though!

The fact that predators are a lot more active in high pressure weather conditions during the winter is cut and dry.

I feel fairly confident that they can also detect changes in pressure there fore the imenant change in weather conditions.I base this on several situations as I described earlier.

It doesnt matter if the change of pressure "affects" them or not the point is can they sense/feel it.If not then how do they know the weather (as dictated by the air pressure) is going to change? and I believe they do know.

Any one doubts that pike are more active in high pressure then your more than welcome to come and spend a winter piking with me! it is not a clever theory just a simple fact that has been shoved in my face time and time again by experience over a lot of years.

Now as for why the weather affects certain species Im not sure but would hazzard a guess that during high pressure conditions (normal weather assosiated with high pressure in Winter is hard frosts,bright light caused by a lack of cloud cover.) is some how more suitable for pike to actively hunt.Lives and lures allways score best and multiple catchs are the norm.Also incidently these same conditions are very difficult to catch silver fish in.Is this because they are in active due to the pike being so active? or is it the other way around?

Low pressure conditions are normally warmer (dont forget Im talking winter here)/milder due to cloud cover,much duller and often windy.Ever noticed how these seem to be good silver conditions in winter? especially for carp.Pike fishing is traditionally much slower with static deadbaits hard on the bottom being the better option.

Its easy enough to come up with ideas as to why the fish do things in different weather conditions but the real mystery is how they seem to be able to predict these comming conditions certainly before the actual "visual" or thermal/light conditions actually change enough for us to percieve?

Doesn?t a drop in barometric air pressure also resonate through the water column at the same level?
I really don?t know the answer to this, so could somebody explain why it wouldn?t if that?s the case?

I think that weather conditions affect temperature and oxygen content of water. There is a optimum temperature of about 14 deg C when O2 diffuses best into water. This is helped by ripples or waves on the water, or by weirs or white water.

I do know about this, and what Ron has written is about correct. Hence why in the winter silver fish come on the feed in low pressure, which incidentally and in the main, bring mild wet windy weather from the SW. Increasing slightly the water temperature and vastly the defused oxygen content of the water through the wave action caused by the wind. In short it gives it a good mixing.

The harder it blows the more readily and longer the fish will feed.

I spent many years fishing for large mouth and small mouth bass. Both species are predators - big time. A settled period of high pressue brought the best sport.

The approach of a weather front ALWAYS (I hate using that word in angling) knocked the fish right off.

On the other hand the period following a good thunderstorm often saw the bass hitting lures extremely well. Hail however was the kiss of death.

That 14 deg C barrier is also interesting. Most fish are at their fighting best when the water is 14 deg C or thereabouts. And that seems to go for all species. The answer is that there is more O2 in the water and therefore the fish have more energy.

As regards moon phases - well I don't know. I have caught lots of fish when all the old wives tails tell us it's all wrong due to the moon, and I have blanked when the moon is supposed to be right.

I guess we will never know all the answers.

"I guess we will never know all the answers."

And I for one am very glad of that Ron!

Old Ray Webb once told me that the best winter conditions for pike were during a strong westerly to south westerly blow with bright skies.

If I think back, these were also the conditions when I made my own biggest bags of pike.