Missing Salmon Project – update 2

Secret Angler

Well-known member
Points
48
Location
London
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

Well-known member
Points
28
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

Well-known member
Points
48
Location
London
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

Well-known member
Points
28
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

Well-known member
Points
48
Location
London
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

Well-known member
Points
18
Location
Western Isles, Scotland
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

Well-known member
Points
18
Location
Western Isles, Scotland
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

Well-known member
Points
48
Location
London
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?
 

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