Missing Salmon Project – update 2

Secret Angler

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I've had a quick look through now the academic literature on this topic. Since the major declines are relatively recent, there are not many papers yet.

Two extracts:
Long-distance migration of Atlantic salmon (Salmo salar) is known to result in high levels of mortality. For a species experiencing global population decline, it is thus vital to better understand migration behaviour, both in the river and marine stages. Atlantic salmon smolts (n=50) were tracked using acoustic telemetry in the River Deveron, Scotland, and adjacent coastal area. Higher rates of mortality were observed in the river (0.77% per km) than the early marine stage of migration (0.0% per km). Mortality likely resulted from predation.
(Lothian, Ecology of Freshwater Fish)

Note this is similar to the AST project with findings similar to the initial ones of AST.

A range of factors in freshwater, from contaminants to river obstructions, changing river flows to temperatures, are known to impact on stocks. Return rates of adult salmon (the percentage of juveniles migrating to sea that survive to return to freshwater) have also declined since the late 1980s. For many stocks, return rates are now at the lowest levels in the time-series, even after the closure of marine fisheries. This reduced survival is thought to reflect climatic factors and broad-scale changes in ocean ecosystems as well as factors in freshwater. (ICES)

ICES is a good open source. It produces a regular (very long) report.
 

loxie

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I've had a quick look through now the academic literature on this topic. Since the major declines are relatively recent, there are not many papers yet.

Two extracts:
Long-distance migration of Atlantic salmon (Salmo salar) is known to result in high levels of mortality. For a species experiencing global population decline, it is thus vital to better understand migration behaviour, both in the river and marine stages. Atlantic salmon smolts (n=50) were tracked using acoustic telemetry in the River Deveron, Scotland, and adjacent coastal area. Higher rates of mortality were observed in the river (0.77% per km) than the early marine stage of migration (0.0% per km). Mortality likely resulted from predation.
(Lothian, Ecology of Freshwater Fish)

Note this is similar to the AST project with findings similar to the initial ones of AST.

A range of factors in freshwater, from contaminants to river obstructions, changing river flows to temperatures, are known to impact on stocks. Return rates of adult salmon (the percentage of juveniles migrating to sea that survive to return to freshwater) have also declined since the late 1980s. For many stocks, return rates are now at the lowest levels in the time-series, even after the closure of marine fisheries. This reduced survival is thought to reflect climatic factors and broad-scale changes in ocean ecosystems as well as factors in freshwater. (ICES)

ICES is a good open source. It produces a regular (very long) report.
Not even close.

There will be 2 or 3 folk at least on this thread who could quote the well known studies without resorting to google. what I'm looking for might be an answer like: "Shearer is far too low for the N Esk as his smolt counting was wrong due to.... or the Frome data use a different methodology pre 2001 and therefore aren't accurate before then. You know stuff about facts not fiction. The ICES PFA estimates are laughable at best by the way. Also if you look at the literature the alledged decline in marine survival was first mentioned by Calderwood in 1920, and was repeated regularly including Spencer 1968, Falkus 1984 and pretty much every salmon action plan published by the NRA/EA since 1993. It's by no means a new thing.

sadly I think you are right about one thing, I am wasting my time.
 

Secret Angler

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Not even close.

There will be 2 or 3 folk at least on this thread who could quote the well known studies without resorting to google. what I'm looking for might be an answer like: "Shearer is far too low for the N Esk as his smolt counting was wrong due to.... or the Frome data use a different methodology pre 2001 and therefore aren't accurate before then. You know stuff about facts not fiction. The ICES PFA estimates are laughable at best by the way. Also if you look at the literature the alledged decline in marine survival was first mentioned by Calderwood in 1920, and was repeated regularly including Spencer 1968, Falkus 1984 and pretty much every salmon action plan published by the NRA/EA since 1993. It's by no means a new thing.

sadly I think you are right about one thing, I am wasting my time.
Oh ye of little faith (or serious engagement). I don't resort to google (unlike yourself). I use the science citation index to find relevant papers. Some are public domain; many are not. ICES is obviously public and contains much useful information.

You say estimates are 'laughable'. How are you qualified to say that? Certainly there have been concerns about salmon stocks for some time, but citing (incompletely) old sources is not to say modern ones are unreliable.

Anyway, science is clearly not your thing.
 

loxie

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Oh ye of little faith (or serious engagement). I don't resort to google (unlike yourself). I use the science citation index to find relevant papers. Some are public domain; many are not. ICES is obviously public and contains much useful information.

You say estimates are 'laughable'. How are you qualified to say that? Certainly there have been concerns about salmon stocks for some time, but citing (incompletely) old sources is not to say modern ones are unreliable.

Anyway, science is clearly not your thing.

ICES PFA estimates are laughable because the method is designed to estimate pelagic fish stocks and doesn't work for andromodous fish. In addition it is ludicrously outdated in that it is unadjusted for effort and it doesn't account for rod caught fish that are released.

you are trying to defend a premis that there has been a massive decline in smolt to adult ratios, asserted by AST, in the last 40 years but don't realise that you need 40 year old data to prove it?!! And then you say I don't do science?!! From what you've posted on this thread so far it is perfectly clear you don't know the first thing about Atlantic Salmon. I suspect that your claim to be a scientist is based on doing a school biology project.


show me a measured smolt adult ratio 5 year average of over 10 on any U.K. river prior to 1990 and I'll engage. If you can't manage that then give up.
 

Secret Angler

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ICES PFA estimates are laughable because the method is designed to estimate pelagic fish stocks and doesn't work for andromodous fish. In addition it is ludicrously outdated in that it is unadjusted for effort and it doesn't account for rod caught fish that are released.

you are trying to defend a premis that there has been a massive decline in smolt to adult ratios, asserted by AST, in the last 40 years but don't realise that you need 40 year old data to prove it?!! And then you say I don't do science?!! From what you've posted on this thread so far it is perfectly clear you don't know the first thing about Atlantic Salmon. I suspect that your claim to be a scientist is based on doing a school biology project.


show me a measured smolt adult ratio 5 year average of over 10 on any U.K. river prior to 1990 and I'll engage. If you can't manage that then give up.
You keep going on about data but don't actually come up with any. As for qualifications, what are yours? I don't need to prove anything to you. Science is my job (and I have the training to match), so I think that may give me an advantage over you. All you've done so far is try to question my credentials, which is the hallmark of one without any.

What is actually laughable is for you to question ICES work without backup.
 

Laxdale

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This has all been done to death elsewhere.
Including why ICES PFA estimates are questionable.
To let secret angler catch up, here is a starting point in your quest for enlightenment.


Then use your searching skills to broaden your knowledge, and perhaps challenge the views that were put forward.....
 

Laxdale

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Links to two more relevant comments (They are relevant to the MSP because the MSP MUST be based on flawless, robust science or the RSPB will tear it to shreds). Modelling (guesstimates) is not robust science....


 

Secret Angler

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This has all been done to death elsewhere.
Including why ICES PFA estimates are questionable.
To let secret angler catch up, here is a starting point in your quest for enlightenment.


Then use your searching skills to broaden your knowledge, and perhaps challenge the views that were put forward.....
I've been looking at the science literature rather than another forum. (And I am not the one challenging the science.) However, the post you link to criticises the EA using ICES figures, which are the figures criticised here.

Frankly I'm more inclined to pay attention to the biologists who work on this than a few fishermen on a forum. That's not to say the scientists are always right, but if a layman is going to challenge them, they'd better offer more than a link to another forum. If you have an argument against the AST's position, then get the data that is public and do an analysis.

Do you ignore the specialist advice on Corvid19?
 

GEK79

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Tags don't harm the fish. If they did there would be no point putting them in to track them. It's a worthwhile project, notwithstanding impertinent photos.
And when the Salmon are all gone what will we do.. Or say we should have done more.. I was down the river yesterday and a salmon leapt I've not seen this before may not see it again.. It scared the life out of me.. I tried to put my fly on its nose but no joy.. Let's hope they can be saved and revived..
Gary
 

raphael

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In southern Brittany, River Scorff is followed up for decades:
(sorry, in French, but the tables can be read nevertheless)
Fry and parr abundance is measured yearly, smolts and adults are all counted and yes it looks something is going bad at sea... Adult average size and weight are decreasing, juvenile production has dramatically increased but the number of returning adults remains low and the trends still looks slightly going down.
But, is that only for that river or for all other rivers in Europe?
We observe anyhow that for some rivers with ongoing restoration works in Normandy, the smolt/adult rate is higher than elsewhere: less young fish, means bigger ones (up to 18/20cm and sometimes more, 50-80g!), then stronger and healthier, and with better return success. Some rivers looks somewhat going better sometimes (let's have a look to IFI reports for example), or at least keeping steady.

The only certainty is that stocks severely depleted almost everywhere in the 80s, but on the other hand is that only due to lower smolt/post smolt survival? In my opinion the question remains open. It is sure that there were many, many more salmon until the mid-80s (the catch reports- angling and commercial-are available to a large extent and speak by themselves). Hence it can be supposed all those fish were able to produce many more smolts but there is a limit due to density-dependance for fry and parrs... The assertion about young to adult survival rate decrease is based on this: any river cannot produce more smolts than what its resources allow (i.e food and shelter).
So what initiated the collapse in the eighties? Why did this event happen suddenly and so much broadly? Most probably a full set of those accumulated aggression to environment that we can hardly reverse without a powerful will to overcome the present situation... And it's not only about salmon but some birds and insects too, while some others are thriving due to better situation for them and better adaptability from them.

I met some scientists here and they say that as we know nothing yet about that possible sea issue, the only thing we can do until now is to try to increase smolt production... I'm a bit skeptic about the research for some alleged poor sea survival. I'm not saying it does not exist, I'm just pointing at the poor situation of many rivers that are unable to carry the salmon population they deserve (as well as trout, pike, grayling, minnow, sculpin, shad, dace, lamprey, etc... all sensitive species). May be we shall start the recovery work here, cause the roots are known, as well as the solutions we are able to apply immediately: let's clean and free the water.

R
 
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loxie

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The simple fact is trying to engage with SA is an absolute waste of time. The long term s:a ratio, where measured has always averaged 2 to 8% going back as far as there are records and that is what it is today. It varies tremendously from year to year and from river to river and the idea there there is or has been a step change drop is a fallacy with no evidence to support it. Neither SA, who clearly has a very limited knowledge of salmon, nor any one else has, or can, produce data to show any such drop. Incidentally I believe that, behind the scenes at least, AST now fully accept this and are shifting there efforts to freshwater.
 

GEK79

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The simple fact is trying to engage with SA is an absolute waste of time. The long term s:a ratio, where measured has always averaged 2 to 8% going back as far as there are records and that is what it is today. It varies tremendously from year to year and from river to river and the idea there there is or has been a step change drop is a fallacy with no evidence to support it. Neither SA, who clearly has a very limited knowledge of salmon, nor any one else has, or can, produce data to show any such drop. Incidentally I believe that, behind the scenes at least, AST now fully accept this and are shifting there efforts to freshwater.
If we can conserve the stock we have somehow stop ruining our oceans and waterways perhaps monitor the trawling at sea then perhaps this species can be saved.. We can hope.. We have to..
 

loxie

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I think salmon as a species are just fine. They are certainly not endangered or even threatened. The issue is that some river systems are heavily impacted by human activity and in these rivers salmon numbers are not plentiful enough to provide good angling. The salmon conservation sector relies on donations to fund their organisations: up to 80% of money raised is spent on staff renumeration and office costs. Without sending out messages of doom and gloom to anglers they will never raise the money to pay the 6 figure salaries earned by some of the chief executives. Thus we have been fed a diet of bulldust about how if we don't act now (donate) we will be unable to save our salmon ( pay our inflated salaries).

Some of this years grilse runs are little short of biblical and it probably should be remembered that the all time record Scottish rod catch was only 10'years ago. There are serious threats to many rivers, particularly in England, but they are nothing to do with the deep ocean.
 

Secret Angler

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I think salmon as a species are just fine. They are certainly not endangered or even threatened. The issue is that some river systems are heavily impacted by human activity and in these rivers salmon numbers are not plentiful enough to provide good angling. The salmon conservation sector relies on donations to fund their organisations: up to 80% of money raised is spent on staff renumeration and office costs. Without sending out messages of doom and gloom to anglers they will never raise the money to pay the 6 figure salaries earned by some of the chief executives. Thus we have been fed a diet of bulldust about how if we don't act now (donate) we will be unable to save our salmon ( pay our inflated salaries).

Some of this years grilse runs are little short of biblical and it probably should be remembered that the all time record Scottish rod catch was only 10'years ago. There are serious threats to many rivers, particularly in England, but they are nothing to do with the deep ocean.
That's not what the scientists working in the area think. I also think your salary figures are exaggerated - these aren't major companies.
 

Secret Angler

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Neither SA, who clearly has a very limited knowledge of salmon, nor any one else has, or can, produce data to show any such drop. Incidentally I believe that, behind the scenes at least, AST now fully accept this and are shifting there efforts to freshwater.
My knowledge is limited, sure, but sounds like yours is more limited still. Sounds to me you are just guessing wildly. There is data, and you can at least find summaries online.
 

aenoon

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I think salmon as a species are just fine. They are certainly not endangered or even threatened. The issue is that some river systems are heavily impacted by human activity and in these rivers salmon numbers are not plentiful enough to provide good angling. The salmon conservation sector relies on donations to fund their organisations: up to 80% of money raised is spent on staff renumeration and office costs. Without sending out messages of doom and gloom to anglers they will never raise the money to pay the 6 figure salaries earned by some of the chief executives. Thus we have been fed a diet of bulldust about how if we don't act now (donate) we will be unable to save our salmon ( pay our inflated salaries).

Some of this years grilse runs are little short of biblical and it probably should be remembered that the all time record Scottish rod catch was only 10'years ago. There are serious threats to many rivers, particularly in England, but they are nothing to do with the deep ocean.
Loxie, think your pulling figures out of your own bulldust now!
Quick search of AST accounts would tell you that.
regards
Bert
 
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