Different strains of salmon running the same system?

Cookie-boy

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It's always interested me how entire river systems produce different strains of fish that run them. My own experience of fishing the A'an for 35 years has taught me that A'an fish are quite different from Spey fish and that Livet fish (known as "Livet Darts" for obvious reasons) are obviously different again from A'an fish. One year when the junction of the A'an got dredged to allow easier access for fish we started picking up Spey fish, deep broad shouldered fish that started coming up in great numbers. That was a week to remember and the hue and cry that followed soon had the gravel put back! But I'd be interested in others experience of how nature has prepared these incredible creatures for adapting to the different streams of the same system.
 

marty31

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Till seatrout are different from tweed ones, a good proportion are skinny things about 2.5 pounds, you get bigger broader ones as well, but the skinny ones are definitely a different strain
 

lefthandup

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Till seatrout are different from tweed ones, a good proportion are skinny things about 2.5 pounds, you get bigger broader ones as well, but the skinny ones are definitely a different strain
Interesting Marty regarding the Tweed...
I've always found Tweed salmon long and skinny but I've had some belters with broad shoulders and small heads, wonder if these are a different strain.
 

MCXFisher

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Hull University are running a long study into the genetics of salmon in the Ouse system. Hopefully, in the long term this will give us a steadily improving picture of any differentiations between the 8 rivers that comprise the system. And of course, the complicating factor of straying is superimposed on the picture as a background variable.
 

nickolas

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Here are three fish caught 13 years ago in late November on the tweed, bottom fish 12lbs top fish 27lbs, this photo is typical of a days fishing then when there was and autumn run.
 

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Loxie

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There was a DNA study done on the Exe and Barle a few years ago which could not find a difference as there was so much straying.
 

marty31

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Here are three fish caught 13 years ago in late November on the tweed, bottom fish 12lbs top fish 27lbs, this photo is typical of a days fishing then when there was and autumn run.
I remember those days well! You spent the whole season looking forward to the famous tweed backend! Kept all your holidays for oct- nov and have grassed my fair share of fish re the above! But is that a strain of fish thats now finished/ wiped out? Looks very much that it is? Lucky now if in these late month's you grass a small freshish grilse! The rest all river fish!
 

Loxie

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I remember those days well! You spent the whole season looking forward to the famous tweed backend! Kept all your holidays for oct- nov and have grassed my fair share of fish re the above! But is that a strain of fish thats now finished/ wiped out? Looks very much that it is? Lucky now if in these late month's you grass a small freshish grilse! The rest all river fish!
They'll be back, but not for 60 years probably. The good news is we will get great summer fishing, no leaves, no fly only and fresh sea trout in the mix.
 

marty31

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They'll be back, but not for 60 years probably. The good news is we will get great summer fishing, no leaves, no fly only and fresh sea trout in the mix.
The sixty year bit! Seems about right relating to what the netsmens families experienced, and as its been experienced they talked of famine inbetween the adjustment! If last year was anything other than a one off (like 2010) it seemed hopefull, that the change from predominant autumn runs of bigger fish, to late spring-summer runs of mainly decent sized fish is well under way! This (to me) leaves the question, of why would fish do this? Why choose to run a warm river, with a good chance of low weedy water, then hug the lower/bottom river? With reluctance to move into the normally better productive beats! Mmm we wait in anticipation and take the cards we are dealt! We have no other option 😥😥
 

Loxie

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The sixty year bit! Seems about right relating to what the netsmens families experienced, and as its been experienced they talked of famine inbetween the adjustment! If last year was anything other than a one off (like 2010) it seemed hopefull, that the change from predominant autumn runs of bigger fish, to late spring-summer runs of mainly decent sized fish is well under way! This (to me) leaves the question, of why would fish do this? Why choose to run a warm river, with a good chance of low weedy water, then hug the lower/bottom river? With reluctance to move into the normally better productive beats! Mmm we wait in anticipation and take the cards we are dealt! We have no other option 😥😥
God alone knows what makes them do what they do! I count myself lucky to have had a bit of the Tweed Autumn fishing and hope that I get some good fishing again at whatever time of year it comes. It's easy to forget that even in its current lull no other river produces as many fish as the Tweed.
 

Aidan Rocks

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What triggers a fish to stop feeding and move to spawn. There are lots of factors and most of which we do not know. I often wondered if number of nets off the Irish coast drove the size of the grilse down. Only small fish could fit through the nets to spawn. Is this anything to do with us or is it just the natural cycle? I guess we will find out.
 

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Interesting your thought, 20 + years ago I fished the Erith in co Mayo, half way through the week we had a spate, the following day 7 fresh fish were caught, 6 of them with net marks and all about 4lbs, the 7th was a very clean and fresh fish but with seal marks and fin missing.
 

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In my ten years fishing the North Esk both in late spring and autumn there was much talk of the legendary back end greybacks. I never saw one let alone caught one. Can we assume this strain has now gone?
 

Aidan Rocks

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I suppose if they spawned in a specific trib but no longer can perhaps yes as their gene pool will be diluted at best! But nature is a stubborn girl and hopefully can surprise you! My experience was in the Gweebarra ca 20 years ago. Ca 40 fish (not all mine) which were all net marked bar one 6 lb fresh fish caught at the very end of the season. Almost like farmers driving the quality of their flock of sheep but on a larger scale. Not many of the nets were legal and the pubs openly sold sea trout. However, the river was full of fish. Then the sea trout started showing up covered in lice and their numbers crashed.
 

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The South Tyne enjoys some small numbers of fish that are very deep bodied and it is said that they represent a fish population from aeons ago. I have taken two such fish, both pre summer runners. I am unsure if the folk memory of deep bodied fish refers to wild fish or fish stocked early in the history of Kielder raised stockings.
 

nickolas

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In my ten years fishing the North Esk both in late spring and autumn there was much talk of the legendary back end greybacks. I never saw one let alone caught one. Can we assume this strain has now gone?
In my time I have seen them go on the Esk,Annan,Nith and Tweed. Will they come back with the present fishery controls world wide let alone on these shores I very much doubt it, but I bloody hope I’m wrong. unless the general public are going to change there eating habits, even the likes of Attenborough with his huge coverage is finding it difficult with the ear of world leaders. once the wild fish have gone it will be down to just farmed fish in the seas, rivers and in the shops.
 
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charlieH

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There was a DNA study done on the Exe and Barle a few years ago which could not find a difference as there was so much straying.

But on the other hand, some years ago I read of a survey on the Tana that identified something like 14 distinct populations of salmon in that, admittedly huge, river.

Hull University are running a long study into the genetics of salmon in the Ouse system. Hopefully, in the long term this will give us a steadily improving picture of any differentiations between the 8 rivers that comprise the system. And of course, the complicating factor of straying is superimposed on the picture as a background variable.

You will know better than me, but how many of those eight rivers can be said to have had a consistent run of salmon over the last 80 years or so?

It seems to me that any river system that has previously lost its indigenous fish stock and is still in the early stages of repopulation, which, by definition, will be by straying (no doubt including, but not limited to, fish from one branch - such as the Ure - wandering into other parts of the system), can hardly be expected to have sufficiently stable populations to start looking for differences between them. If your spawning stock is composed of more or less random blow-ins (didn't they identify about 30 different sources for the fish caught in the Mersey?), surely their mongrel offspring need to be exposed to the process of natural selection over a good many generations before they can ever be expected to arrive at a settled population. Furthermore, if you have a lot of available habitat and - at this stage - far too few fish to populate it, natural selection isn't really going to work in the early years, as the element of competition that drives 'fitness' and hence lead to population distinctiveness, is all but absent.

You mention that this is intended to be a long term study, but I think that looking for results too rapidly could potentially be misleading. How many generations of fish do they propose to study before they start trying to draw useful conclusions?
 

MCXFisher

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Charlie,
as ever you're on the money with your questions. Of the 8 major rivers in the Ouse system, we can only be certain that one of them lost its entire salmon population, whereas 3 others probably did. The other 4 rivers almost certainly retained a small residual population, which, owing to the fact that it could only run in early spring and late autumn owing to the oxygen barrier below Selby, was largely invisible and unreported. There is, however, good anecdotal evidence of a small residual population in the Ure across the entire period, including after the EA's declaration of extinction.
An earlier research project undertaken some time ago now indicated a distinct 'Yorkshire' population, which tends to support that thesis, but did not suggest any specific differentiation between the component rivers. In my recent discussions with the local EA scientists, they considered that by and large the natives continued to outnumbers the strayers in those parts of the system where the recovery was based on survivors. That said I differ with the EA in terms of the percentage of straying: my beliefs are significantly higher (~10-15%) than the evidence they deploy (2-5%). But in any case I think you're right that there will be quite a lot of mixing going on, and the early years of the Hull study may help to illuminate its extent. Currently I'm unaware how long they propose to sustain the research: in academia this things tend to live only as long as the combination of funding and the tenure of the proponent!
 
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Loxie

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But on the other hand, some years ago I read of a survey on the Tana that identified something like 14 distinct populations of salmon in that, admittedly huge, river.



You will know better than me, but how many of those eight rivers can be said to have had a consistent run of salmon over the last 80 years or so?

It seems to me that any river system that has previously lost its indigenous fish stock and is still in the early stages of repopulation, which, by definition, will be by straying (no doubt including, but not limited to, fish from one branch - such as the Ure - wandering into other parts of the system), can hardly be expected to have sufficiently stable populations to start looking for differences between them. If your spawning stock is composed of more or less random blow-ins (didn't they identify about 30 different sources for the fish caught in the Mersey?), surely their mongrel offspring need to be exposed to the process of natural selection over a good many generations before they can ever be expected to arrive at a settled population. Furthermore, if you have a lot of available habitat and - at this stage - far too few fish to populate it, natural selection isn't really going to work in the early years, as the element of competition that drives 'fitness' and hence lead to population distinctiveness, is all but absent.

You mention that this is intended to be a long term study, but I think that looking for results too rapidly could potentially be misleading. How many generations of fish do they propose to study before they start trying to draw useful conclusions?
I suspect there were more fish to test from the Tana!!
 

Ness Glen

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It's always interested me how entire river systems produce different strains of fish that run them. My own experience of fishing the A'an for 35 years has taught me that A'an fish are quite different from Spey fish and that Livet fish (known as "Livet Darts" for obvious reasons) are obviously different again from A'an fish. One year when the junction of the A'an got dredged to allow easier access for fish we started picking up Spey fish, deep broad shouldered fish that started coming up in great numbers. That was a week to remember and the hue and cry that followed soon had the gravel put back! But I'd be interested in others experience of how nature has prepared these incredible creatures for adapting to the different streams of the same system.
I have heard it said, back in the day, when the catch was lined up on the slab at the end of the day, that the A'an fish were easily identifiable as they were longer and leaner fish. Cookie-boy, can you remember which year the A'an mouth dredging occurred? It would be interesting to look at the A'an catches that year in detail.

Further up the A'an we noticed that the fish spawning in the Burn of Loin were mainly grilse, whereas in the nearby Builg Burn they were mainly small salmon (7-9lb). The distinction we saw was quite striking. We thought at the time it may be due to the large waterfall that lies between the confluences of the two burns, but there must be more to it than that.
 

Cookie-boy

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It would have been during the early to mid 90's because we were staying at Marionburgh house at the time. After that was decreed too good for us and made exclusive for Ballindalloch Spey fishermen we moved upstream to Minmore House Hotel at Glenlivet. The hotel had a photograph album in the lounge that had all our party's catches in it that included Spey, A'an and Livet fish. It was a remarkable document and sadly lost now. The sea trout that ran the A'an at that time were the plumpest, fattest fish I have seen. 5lb, 6lb specimens were not unusual and in that album was a picture of a 15lb sea trout taken by myself from the Boat Pool.
 
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