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  1. #11
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    Default Re: How to locate grayling

    Quote Originally Posted by bobmiddlepoint View Post
    Surely the warm deoxygenated water from the body of the pool is still warm and deoxygenated as it speeds up at the pool tail and into the head of the next pool. Ok if the water is rough and turbulent some extra oxygen might dissolve into it but it is still warm.
    The reason they go into fast water in summer is to get to the food first, if they stayed down in the pool body they would miss out on all the grub to the fish that went to the head of the pool. In the quicker water the flow is bringing them food faster and they are feeding hard.

    Being cold blooded once the temps drop too far they can't generate enough energy to stay in the quick water for long so they drop back to slower water.
    Oxygen levels change across the 24hr cycle. I believe aquatic plants produce oxygen during the day and carbon dioxide at night, and when oxygen levels drop creatures move. The most likely place to find more dissolved oxygen is in the fast, broken water.

  2. #12
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    Default Re: How to locate grayling

    On my local river I notice grayling rising most days on deep , flat slow moving pools , they seem to be resident fish that stay in that type of water all year round , I suspect they are feeding on mainly midges , aphids around this time of year and BWO in the Summer , although these BWO hatches are rare these days , maybe BWO hatches happen through the night when I am not there .

    I am in a lucky situation as my river is prolific in trout and grayling numbers , so I am in a good position to explain things about grayling lies .

    Just as a example I managed grayling from 3 kinds of water yesterday , a dozen in fast water , a dozen from semi faster water in the middle of the pool and 28 grayling from very sedate dry fly water , these were on the dry flies .


    I was also doing this type of fishing from the 15th of June , catching plenty of grayling on nymphs and Spiders from faster water , only to switch over to dries and target the grayling from the flats , or very slow moving water .


    I can soon build a picture up on the fishing and the nature of the grayling , this area is around a quarter of a mile long .


    In reality I don't even need to be fishing to take in information , I can observe the water and just watch the rising grayling in the deep pools and even at certain times you can get a localised hatch or fish rising in faster water .


    Now when we do get the really cold snaps , I am talking below zero , then fish will drop into deeper water , but that depends on the make up of the river bed , some may move a few feet into slightly deeper water , or some move a lot further .


    Like any kind of river fishing , the more time you spend on the river , then the more knowledge you build up .


    On fishing related matters I can target grayling on any type of water with both nymphs and dries , some days can be good for dry fly fishing , other times nymph fishing can be good , or even a bit of both dry , nymph , Spiders and the Duo all in a single session .

    The urban parts of the river in the middle reaches hold vast shoals of grayling , maybe that's why they hold in most types of water , as you go upstream into the upper reaches the grayling seem to drift out of the very faster water a lot earlier , I tend not to really concentrate on the fast water after October .


    These findings are on a small to medium river in the North East of England , the pools in the upper reaches are not that big , so grayling may move into totally different pools , others may just drop into deeper depression in some pools .


    Trout are more predominant in the upper reaches , could be the grayling can be more selective in which part of the river they want to inhabit at different times of the year .


    Middle to upper reaches of this river are a 50 / 50 ratio , when we reach the middle reaches of the river then its grayling who are in the greater numbers , 15 grayling to 1 trout .
    Last edited by rough diamond; 06-11-2018 at 09:11 AM.

  3. #13
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    Default Re: How to locate grayling

    Quote Originally Posted by Bluepea View Post
    Oxygen levels change across the 24hr cycle. I believe aquatic plants produce oxygen during the day and carbon dioxide at night, and when oxygen levels drop creatures move. The most likely place to find more dissolved oxygen is in the fast, broken water.
    I know everyone has always says there is more oxygen in the rough water but has anyone actually measured it? It would be interesting to see what difference there was on a typical gently running grayling stream between the different parts of a pool. I've done a lot of salmon fishing in small spate rivers and chalkstreams and in hot droughts where do the salmon head? Usually the deepest slowest sections where they can hold station with least effort, they don't seem concerned with lack of oxygen in this water until things become extreme.

    I still maintain the main reason trout and grayling move into fast water in higher temperatures is because they are cold blooded. In cold weather their metabolism is slow, they are sluggish and they can't stay there for long expending energy they are struggling to produce. In warm weather their metabolism is faster and they can take advantage of thee prime feeding lies in the quick water.
    Maxima (or Drennan Sub Surface Green) forever

  4. #14
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    Default Re: How to locate grayling

    Quote Originally Posted by bobmiddlepoint View Post
    I know everyone has always says there is more oxygen in the rough water but has anyone actually measured it? It would be interesting to see what difference there was on a typical gently running grayling stream between the different parts of a pool. I've done a lot of salmon fishing in small spate rivers and chalkstreams and in hot droughts where do the salmon head? Usually the deepest slowest sections where they can hold station with least effort, they don't seem concerned with lack of oxygen in this water until things become extreme.

    I still maintain the main reason trout and grayling move into fast water in higher temperatures is because they are cold blooded. In cold weather their metabolism is slow, they are sluggish and they can't stay there for long expending energy they are struggling to produce. In warm weather their metabolism is faster and they can take advantage of thee prime feeding lies in the quick water.
    A trout's metabolism increases as water temperatures increases therefore, they require much more oxygen when water temperatures are higher. It's a proven fact that faster, broken water holds more dissolved oxygen than slow moving or stagnant water.

  5. #15
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    Default Re: How to locate grayling

    Quote Originally Posted by Bluepea View Post
    A trout's metabolism increases as water temperatures increases therefore, they require much more oxygen when water temperatures are higher. It's a proven fact that faster, broken water holds more dissolved oxygen than slow moving or stagnant water.
    Yes but in the average trout or grayling river could you really call any of water stagnant and deoxygenated to the point that the fish struggle to survive in normal summer conditions. If it was that bad all the salmon and sea trout (in rivers that hold them) would be stacked up in the fast water too but they aren't unless they are looking to run.

    The main reason feeding trout and grayling go into fast water in warm conditions is because that is where the food is concentrated by the narrower (or shallower) stream cross section and the food is brought to them faster. In winter there is not enough food coming down to make it worth their while to try to hold station in the fast water - they would expend more energy than they would replace with the slim pickings coming downstream, so they drop back to quiet water and conserve energy and pick up what they can.

    There is really no need to start thinking about dissolved oxygen levels to explain trout and grayling behaviour until they start going belly up by which point you should have stopped fishing for them anyway!
    Maxima (or Drennan Sub Surface Green) forever

  6. #16

    Default Re: How to locate grayling

    Well worth a look at the info from the guys at Discover Tenkara. They have plenty of stuff directly or indirectly related to grayling but Id start by looking here
    Grayling Fishing: Ultimate tactics, tackle & insider tips

    Having just read this piece again Id forgotten just how informative it is.

  7. #17
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    Default Re: How to locate grayling

    Quote Originally Posted by bobmiddlepoint View Post
    Yes but in the average trout or grayling river could you really call any of water stagnant and deoxygenated to the point that the fish struggle to survive in normal summer conditions. If it was that bad all the salmon and sea trout (in rivers that hold them) would be stacked up in the fast water too but they aren't unless they are looking to run.

    The main reason feeding trout and grayling go into fast water in warm conditions is because that is where the food is concentrated by the narrower (or shallower) stream cross section and the food is brought to them faster. In winter there is not enough food coming down to make it worth their while to try to hold station in the fast water - they would expend more energy than they would replace with the slim pickings coming downstream, so they drop back to quiet water and conserve energy and pick up what they can.

    There is really no need to start thinking about dissolved oxygen levels to explain trout and grayling behaviour until they start going belly up by which point you should have stopped fishing for them anyway!
    I'm not going to get into a protracted argument about whether or not trout move into fast water to get more food or in search of more oxygen. My understanding is that their requirement for oxygen in warmer water is greater as their metabolism increases, and, as water temperatures rise, the oxygen levels fall - bit of a catch 22, as they say.

    Bearing in mind that being on the fin and hunting food is a fairly hefty activity and increases their oxygen demand even further, they are unlikely to hang around when dissolved oxygen levels drop below what they require.

    Again, I'm no expert, but salmon tend to lie dormant for long periods and really only undertake strenuous activity when there is enough fresh water in the system. They do possess the ability to regulate oxygen intake when conditions dictate, for example, watch a salmon (and I'm no expert on them) and you'll see increased gill movement in order to increase their oxygen intake - I believe it is called oxyregulating.

    Again, I'm no raving expert, but if you observe sea trout in the day (which I do often) they do tend to lie doggo and come to life at night in the summer months. Ok, that's a generalisation, but it illustrates the behaviour. And make no mistake, when conditions dictate salmon will move to find more oxygenated water.

    If you really think the time to start thinking about dissolved oxygen levels is when trout go belly up, you really are missing the point. I was severely chastised by our guide (an aqua biologist specialising in grayling) at a European championship a few years back for not carrying a thermometer, "how the hell do you know where the fish will be if you don't know what the water temperature is" was his cry?

    It was through him that I also learned that grayling have thinner blood than trout. But that's another story.

  8. #18
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    May 2016
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    Default Re: How to locate grayling

    Thanks for the very informative answers. I did my first grayling mission yesterday. I didnt see anything rising and the water is peat tinged so I couldnt see the bottom of the pools. I ran some heavy nymphs along the bottom of the pools on a tight line but all i caught were out of season trout. Its the north esk near Edinburgh so i know they are there. It has been suggested that my nymphs are too dull for grayling as they like a bit of colour. Could this be the case? What else could it be? Im going for round two tomorrow!

  9. #19
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    Default Re: How to locate grayling

    Temperature dictates the amount of dissolved oxygen water can hold, barometric pressure also plays a part in dissolved oxygen content.
    Al

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