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Water temperatures

Anthony Pearson

Senior Member
How quickly do water temperatures respond to a rise/fall in air temperatures at this time of year, assuming there is no extra influx of fresh water into the system (i.e. via rainfall)?
 
How quickly do water temperatures respond to a rise/fall in air temperatures at this time of year, assuming there is no extra influx of fresh water into the system (i.e. via rainfall)?

Its a good question, and one that has been popping up in my head too, with the higher temps coming in for a couple of days I am going to give it a go somewhere

From what I understand the response to higher air temperature to water is pretty quick, however water temperatures will take on the averages over a period, I thing the key here is night time temperatures, and with no immediate frosts forecast, that has to help.
 
I would guess that it depends on the depth of the water , strength / direction of the wind , how sunny or otherwise it is . i.e I would imagine that water would warm up quicker if it is relatively shallow fanned by a warm westerly on a sunny day rather than on a dull day with an east wind . Lot's of variables . As generalisation I think that smaller and shallower rivers warm up and cool down quicker than larger waterways
 
Agreed.

Lots of warm rain can warm up a big cold river before too long. Saw that with the Thames last January when we had an extra 6' on :)

Stephen
 
Thanks for that Stephen.

with the higher temps coming in for a couple of days I am going to give it a go somewhere

Neil, my thoughts precisely.

Mike, I'm thinking of the Nidd in particular and hope that there will be a window of opportunity to catch a barbel before the month is out. The gurus always talk about an upward trend in temperatures being a good time to be out, but not betting my house on it though! Watch this space... :)
 
Hi Chaps

I spent years worrying about water temperature; I would always take the temp and record it.
From there I would compare my catch rates and analyse the results, not only for my Barbel fishing but for my Roach fishing and winter Zander, Pike, Chub and Dace.
After many years I have come to the conclusion that there is absolutely no conclusion to come to!

What I can say is that air temperature can make an enormous difference, if it is rising or has risen, even by one degree then I will move heaven and earth to get on the river bank.
If it has fallen, again even by one degree, I invariably fail to catch.
If the air temperature is stable then I may catch, if it is stable and moves up even by one degree I get very confident, if it is stable and drops even by one degree I stay at home because my records prove to me that the possibility of catching is very remote.
Frost of any kind, tends to be bad news, it will kill off chances of decent Roach fishing, but Barbel will often feed for short periods if air temps rise, more so if they rise substantially and the sun comes out, the only problem is that often a frost will bang the colour out of the water (not always but often) and a bright sun will put everything off if the colour has been reduced by frost.
During snowy conditions fishing can improve markedly as often a snow flurry coincides with a slight lift in air temperature.
If snow is on the ground and air temps lift then you might just find that your chances improve, particularly during the warmest few hours of the day.
I have records of a number of occasions when we have experienced several days of stable air temperature, followed by one day when the air temperature rises slightly, even though it was still cold and there was considerable snow on the ground, mid day on the day air temps rise, has provided me with several notable fish, particularly if the temperature drops again thereafter.
During these periods water temperature seems to make little or no odds and as rising water temperature is due to air temperature having risen, taking note of rising water temp is of no consequence as the fish have already fed as air temps rise and fishing during rising water temperatures usually only means that you have missed the boat so to speak!
It is also worth remembering that temperature is not the only thing that triggers fish to feed, so you need to analyse this information along with water levels, water clarity (or colour), air pressure ETC.
Another point worth remembering is that that my fishing is not always done with the usual paste wrapped boilie or pellet, in fact I very often use very small baits particularly in cold water, or I may well use particularly large baits, for example in flood water conditions (a quarter of a large tin of luncheon meat on an appropriate hook), I tend to vary my choice of bait dependent upon conditions as I find them.
In conclusion I must say that I take absolutely no notice of water temperature what so ever, the main reason being that if took the temperature and found it to be 2 degrees above freezing, then checked if I caught on previous similar occasions and found that I did not, I would tend to give up and not bother!
These days I fish anyway and I am not surprised if I do catch!!


I hope this helps?

Tight lines.
 
Yes Nick, I thought so too!

Work gets in the way of the angling classes:mad:

And a pothole in the road has damaged my car suspension, so this weekend is out, can't see my Mrs letting me use her spotless Mini for:-

"Your filthy fishing gear!!"

Place any rude word you may have thought I said here!

Tight lines.
 
I guess what can be deduced from Keith's fascinating reply is that a change in air temeperature however small can have a significant effect on fish feeding behaviour and that the change in temp is responded to [ positively or negatively ] very quickly by the fish . What is also interesting is that in Keith's experience although the fish are obviously surrounded by water it is the change in the air temperature that appears to have the quickest effect on the feeding behaviour not the change in water temperature effected by the change in air temeperature . Fascinating stuff
 
I am influenced by changes in air temperature but mainly because I view it as a reasonable proxy for water temperature. I generally look for relatively stable conditions and temperatures irrespective of whether it's cold or warm. When it's cold an upward adjustment in air temperature which looks like being sustained is a good sign. I do think though that when it's cold, very cold even, the margin of error and difference between catching and blanking is very small. Finding the fish, using the right bait and, perhaps critically of all, at the right time, is key. The fish may be put off feeding for a short while when temperatures tumble but in a sustained cold period, they will need to feed at some point. Last year when we had a long cold snap I fished a couple of days for a few hours in the day with a small maggot feeder and caught on both occasions. I fished when the air temperature was at its highest on those days which was around -1/-2 and had risen from around -4 at the start of the day.
 
Yes Howard, I too have found that in conditions where temperatures are stable, the best time to fish is when the air temp is at its warmest, this tends to be on or just after mid day (but not always) and the feeding spells tend to be fairly short.
I have also found that in these conditions small baits work best, single or double maggot or caster or a small red worm, I also have some 4mm very low oil pellets that I get from Aquabait that also work well.

I also find that as a float angler I can search the whole swim more effectively, cold conditions mean that cold blooded creatures like fish will utilise the minimum of expended energy for the maximum intake of food that will replace that energy at a profit, in particular that food has to be of maximum use to the fish.

The trick in these conditions is to feed very little but often and for me, bait choice is the key, baits with a high potential of energy are all well and good in warm water but can be next to useless in cold water when the fish are un-able to release that potential energy, in very cold water Barbel can digest invertebrates much more readily than baits made up from complex oils and sugars, there is little point in a Barbel eating a bait that it cannot digest, how they know this is beyond me but their instincts seem to give them this edge.

One bait I have found to be very successful in cold conditions is dead maggots, a few years ago I made note that fish like Barbel and Chub when caught in cold conditions would sometimes leave part digested maggots on my un-hooking mat, these maggots came from the vent of the fish and this made me wonder if the fish were excreting these maggots only to re-consume them, thus taking advantage of the pre-digested state of the maggots, rather in the same way a cow will chew the cud to take full advantage of the nutrient from grass or hay.
I could not re-produce the part digested state of the maggot but I could use dead maggots, which I found to be a superb bait in very cold conditions.
I also reasoned that IF fish were on the lookout for partly digested food stuff then that food would by its nature be small.

I have no scientific proof for any of this, all I can say is, a fish or two on the bank when other anglers are blanking is quite a powerful argument.

Again I hope this helps?

Tight lines.
 
If it's of any interest to anyone the water temp on the Dove was 8 degrees on Thursday,shouldn't drop too much over the next few days.:)
 
Some good food for thought there Keith, thanks. Do you mind me asking if you are referring small or large rivers? I only ask as where I fish on the Lower Severn, some swims are in excess of 20 feet deep, which makes me wonder if small changes in air temperature have as much affect as they do in smaller, shallower rivers.
 
Hi Bruce

I am mostly fishing small rivers, but I do on occasion fish larger rivers and I find that the air temperature indicator is just as reliable.

To be fair I am not sure it is the air temperature that affects the Barbel, as you say, why would air temperature make any difference to fish in even one foot of water let alone 20ft of water, it make no reasonable sense at all, that said, I find air temp IS a quite reliable indicator, it is not the only indicator but my average performance has improved markedly since I have been taking note of air temperature.

While air temperature is the indicator I do not believe it is the cause of fish getting on the feed, however if we look to physics we might find the answer.

Guillaume Amontons offered the following theory:-

"The pressure of a gas of fixed mass and fixed volume is directly proportional to the gas' absolute temperature."

This is now known as Amontons Law.

Barbel like all cyprinids have a swim bladder which is controlled in part by a pneumatic valve, they also have a lateral line, an organ for which we do not fully understand, but seems to have a number of sensor cells, some of which can detect pressure.

I am sure Barbel cannot sense air temperature, but I am very sure they can detect minute changes in pressure and it may well be pressure that triggers feeding.

As I said previously I have little scientific proof of this, I have only the result of my experience, but if it is pressure that makes the difference then it will not matter if the rivers are large or small, the laws of physics are the same everywhere.

Obviously except in America where at least one of Newton’s laws of motion is different:-

“For every action there is an exaggerated over reaction!!":D


Tight lines.
 
I agree Keith, the effect of pressure change would seem much more likely to trigger a response in deeper water. Often this would be linked to air temperature, especially if a high pressure cold spell is broken by a big low pressure system from the South West.

Interesting stuff, and adds more things to ponder when fishing through the winter!
 
This is a very interesting thread. I take a lot of notice of air pressure and air temp trends in my angling. That said, what I can't quite get my head around is the assertion that a small rise in air temp will in isolation trigger a feeding response as these rises occur, with the occasional exception, pretty much every day ? On my local river the barbel are very crepuscular in their feeding habits, yet the period around dusk invariably coincides with falling air temps. Suppose the fact that there are so many pieces in the barbel-catching jigsaw is what makes our successes so rewarding !
 
I certainly agree with many of the posts on this interesting thread and find it difficult to come to any certain conclusions.
Last winter I went to the Wey crusting for chub during a very cold spell.
When I arrived just before first light the air temp. was -8 , and the confidence was low when I made that first cast in the half light of dawn. I was surprised when the tip went round almost immediately and found myself playing a good fish through the already frozen tip rings. I ended up taking 7 chub that morning to just under 6 lbs with a roving approach. The funny thing was that the bites dried up at about 10.30 when the watery sun had just warmed the air enough to melt the frost....so perhaps light conditions had a part to play on that occasion.

My pb Wey barbel came an hour before first light on a mild Feb. morning, quickly followed by a good 12 lb'r, then ,.. despite rising temps,.. nought for the rest of the morning!

Pike feeding triggers can be even more thought provoking,..best leave that one for 'other species'.:)
 
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