Smolt tracking

Horsbrugh

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Here is some info on the ongoing smolt tracking work on the Moray Firth.
Hopefully, this might convince some folks that fishery science is essential, if we are to fully understand and get some conclusive proof of what is happening to our fish.


Atlantic Salmon Trust
 

ArchieL

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Good watch and it will be very interesting to see the final results. 50% loss in river before even hitting the sea is not surprising when you see the protection given to non native species like mergansers and sea birds like cormorants. Can we continue as a sport & business with these losses in river ? I would like to see almost every merganser and cormorant in the study area being shot then see the in river survival rate results after a few years. I am not silly and i know it will never happen but i think we will all know the answers. Just seems we are flogging a dead horse trying to get numbers up when we have no control to stop the young fish being predated on by FEB's. Also fling in the seal colonies at almost every river mouth and you wonder why there is reduced runs of fish. In river predation is easily sorted so why are we trying to look for the blame at sea and spend millions of pounds doing so ? What can be done to help the fish at sea once they make the dash out ? Almost nothing IMO as they are microscopic needles in a haystack. Monitoring of the feeding grounds yes.

I think i could have increased the survival rates on these rivers with the same amount of money that the AST and boards have spent during the study period on this project. I would have just allocated the money to keepers and Ghillies to buy cartridges and put them to good use. Hey Presto in river losses down to 5-10 % within 1-2 years and millions more smolts sent to sea.
 
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mows

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Its very interesting.

As to whether its useful depends on what is going to be done with it.

After all, its been directed by the same scientists that are certain its all at sea. (what became of that exceedingly expensive study and film????)

Now, if they were to do the same survey on the west coast to quantify the difference between areas with aquaculture and areas without. It might even be invaluable.

Without doing that, I look at it as way to keep spending money and nothing else.

Watch this space.
Im looking forward to being proved wrong, when they do look at the west coast as well.

Cheers

Mows
 

ArchieL

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You are right Mows and you have hit the nail on the head , Scientists survive and make a living by conducting research so it is not in their interest to just come out and say we are Fxxxed as the FEB's eat them all. What they will do is drip feed information which we lap up then they ask for more funding and more needs to be done etc etc etc. Action is what is required now and if they do find the wholy grail answer is all at sea (Which i don't believe) then could you imagine how long it would take for the countries governments to get round a table and sort it out. Jeez man countries cannot even get round a table and sort stuff out when there is hundreds of thousands of people dying in conflict areas so think about them trying to sort out a salmons plight.
 

Roag Fisher

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All this project has done is illustrate survival rates as smolts move downstream. Not what might have killed the smolts. As there were no control groups of smolts, it is not possible to say if the tags killed the smolts or not.
 

Horsbrugh

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I fully understand the scepticism regarding the scientists but like it or not, without scientific evidence to back up our claims, we only have opinions and speculation to argue our case with. If we are to have any chance of getting any form of licensed control of FEB’s we need the evidence. SNH are very aware of the backlash that would be stirred up by RSPB and other protectionist bodies, if they were to issue any meaningful licences without any scientific justification.
 

Roag Fisher

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Its very interesting.

As to whether its useful depends on what is going to be done with it.

After all, its been directed by the same scientists that are certain its all at sea. (what became of that exceedingly expensive study and film????)

Now, if they were to do the same survey on the west coast to quantify the difference between areas with aquaculture and areas without. It might even be invaluable.

Without doing that, I look at it as way to keep spending money and nothing else.

Watch this space.
Im looking forward to being proved wrong, when they do look at the west coast as well.

Cheers

Mows
Loch Roag on the west coast of Lewis was sea lice soup in the summer of 2018 (remember Garynahine). Grimersta, a grilse fishery, has just had it`s best year in a while in 2019. I would have expected a poor grilse run this year if sea lice were a huge issue to salmon smolts.
 

Horsbrugh

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All this project has done is illustrate survival rates as smolts move downstream. Not what might have killed the smolts. As there were no control groups of smolts, it is not possible to say if the tags killed the smolts or not.
Marine science are apparently conducting trials to measure possible tag shedding and mortality due to the implants.
 

Deepwading

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It's perhaps worth noting that the Tweed has broken ranks from the ‘Alliance’ by publically stating that the numbers of FeBs present on the river is not a plausible explanation for the numbers of surgically tagged smolts that have been ‘lost’.
 

Deepwading

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The then head of the Tweed Foundation raised the question re what it is about surgical tagging that leads to high rates of loss of tagged smolts, at the Source to Sea conference back in the spring of 2017.

The Dee was warned about the potential problems associated with surgical tagging as far back as 2016.
 

Gustav

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An interesting film which is just in reality a shaky first step.
Like it or not the success of any real initiatives to protect and enhance the future of the wild atlantic salmon will be political because any major action will have consequences for other pressure groups or commercial interests and therefore will have to be based on empirical research that stands up to the highest levels of scrutiny and is morally and probably economically the right thing to do.
I understand we are all frustrated at the time this will take but the cause of the collapse of salmon runs is multifactorial, interactive and probably contradictory on occasion too.
 

mows

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Loch Roag on the west coast of Lewis was sea lice soup in the summer of 2018 (remember Garynahine). Grimersta, a grilse fishery, has just had it`s best year in a while in 2019. I would have expected a poor grilse run this year if sea lice were a huge issue to salmon smolts.
Aye, but probably a different result for the lochy etc
 

Jockiescott

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I'm sure I read a few years ago about one super massive flaw in using acoustic tags to track migrating fish. The 'pinging' produced by the tags could be 'heard' by predators like birds, seals and dolphins and was, in effect, like ringing the dinner bell for predators. Even if the tagged fish itself dodged the predator, many of those close by were lost as a direct result of the tag.

There was also some information about mortality as a result of the tag being planted.

I suppose we need some idea of how long smolts remain in the river before getting to the sea and how long they spend around the shoreline and things like that. I suppose there is no better technology available at this time so we have to be doing with it.
 

keirstream

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Loch Roag on the west coast of Lewis was sea lice soup in the summer of 2018 (remember Garynahine). Grimersta, a grilse fishery, has just had it`s best year in a while in 2019. I would have expected a poor grilse run this year if sea lice were a huge issue to salmon smolts.
2018 was also the driest for a long time, reducing those rivers to trickles effectively forcing salmon to live in the sea lice soup you refer to.
2019, being the wettest for a while, so no surprise that rod catches were up with nothing stopping entrance to the rivers.
And so it goes on.
Scientists make their livings out of inconclusive project studies.:(
 

Deepwading

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The Tweed Foundation now estimates losses of about 6% ("ball park figure": April-May) due to @200 Goosander ducks.

This contrasts with a figure of 59% losses of surgical tagged smolts in the river in 2019.

Quite a discrepancy!
 

Roag Fisher

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2018 was also the driest for a long time, reducing those rivers to trickles effectively forcing salmon to live in the sea lice soup you refer to.
2019, being the wettest for a while, so no surprise that rod catches were up with nothing stopping entrance to the rivers.
And so it goes on.
Scientists make their livings out of inconclusive project studies.:(
Grimersta is different to almost all other island burns in that there was enough water for smolts to migrate and adults to escape the sea at all times in 2018. In high water, as in 2019, Grimersta loses a lot of fish upstream. But there were plenty left. I am not claiming Grimersta had a good run in 2019 to support any theory, just reporting an interesting fact.
 

Grassy_Knollington

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They are studying a complex natural system, there isn’t going to be a single silver bullet discovery.

Looking at the high variability in the Dee results over just 2 years, they’re going to have to do this for maybe 5+ years to get any kind of baseline for each river.

Maybe it would have been a better idea to focus more effort on the river than in the Moray Firth. That could have given the time & space to make observations & measurements to correlate with the dropped fish e.g. Merganser in pool tail. Once again, we can see where the money is, and it’s not on the West Coast.

That said, I think this is probably the first AST work which actually seems to make sense to me. The reports will be interesting reading.
 

Ben-Macdui

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Tweedbeats news/editorial last week.

The mystery remains. Whereas both spring and summer catches are similar in numbers to those pre 2014, if very slightly lower, the mid to late autumn run has all but gone completely. And those who blame the RTC, the birds, the seals, or whoever else, for this have one killer question they cannot answer.
Do the birds and the seals kill all those smolts which would come back in the autumn (birds),or salmon that have come back in the autumn (seals), whilst doing no more obvious damage than the pre 2014 norm to spring and summer smolts and salmon?
Clearly that is completely absurd.

its a fair point :noidea::noidea:

BM
 

keirstream

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And those who blame the RTC, the birds, the seals, or whoever else, for this have one killer question they cannot answer.
Do the birds and the seals kill all those smolts which would come back in the autumn (birds),or salmon that have come back in the autumn (seals), whilst doing no more obvious damage than the pre 2014 norm to spring and summer smolts and salmon?
Clearly that is completely absurd.

Not only that, but if, as is universally accepted, the autumn salmon run has collapsed on the East coast and, given that seals are pretty much considered to have moved inshore to plunder the salmon runs, then how are the seals surviving???
Their numbers are exploding, record numbers of pups born in the Forth estuary, no disease, no famine. I can't remember seeing a starving seal.
And yet there are no autumn salmon to feed them?
What are they eating and are we over exaggerating their taste for salmon?
Nothing to do with smolt tracking I know, but part of the overall picture.
 
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MCXFisher

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I concur strongly with Grassy Knollington's comment. There are so many variable in play that it's essential to establish a long enough time base of data to get a clearer picture of what's actually happening. I judge that 5 years would be a minimum: that way you can cover in-river variables (Keirstream's point); and get a better handle on the existence or otherwise of a 'tagging factor'.

No matter what people may think of fishery scientists I suggest that they are right in this case to be cautious and to seek more data. As I've said before on the Forum, in my (long) experience, cries of "something must be done" generally lead to doing the wrong thing in haste. This research is far more useful and economic than chasing will o-the wisps around the Norwegian Sea in a very expensive trawler, and I for one think it is a valuable first step.

One of the things we need to understand (amongst many others) is whether there are significant river to river variations in in-river smolt mortality that may help us to identify localised adverse factors which can potentially be mitigated.

I am also reassured by a general consistency with the Canadian research conducted within the SALSEA project about 4-5 years ago. They found high levels of mortality in the exit phase, but once the smolts were adjusted and away in the high sea, the death rates diminished toward zero (the study tracked them for extended distances out into the Labrador Basin). This observation of attrition being density related conforms to normal operational analysis outcomes.

Amongst all this we need to remember that the way in which smolts migrate in mass is a well-established evolutionary survival strategy - "they can't eat us all" - which is superimposed on the very large number of eggs laid by female salmon. High attrition is therefore anticipated within the system. Mathematically the key to success is maximising the number of smolts at the start of migration, and owing to the 'gearing' in the equation, small percentage changes in the early stages can have disproportionate effects in adult numbers 1-4 years later.

For example, egg to smolt mortality is commonly in the range 97-98%, i.e. the average hen may produce between 100 and 150 smolts. An output of 100 is robust to 50% migration losses and a 6% return rate while maintaining a stable population. What the numbers suggest is that in-river migration mortality has always been quite high. The key question is what is normal? (I don't know)
 

AlanT

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A problem such as this, with many potential causes is immensely complex, and thus costly and time consuming to reach any kind of robust conclusion

I dont particularly think the scientists are particularly drip feeding information, I believe that this is just the rate of progress in such a large project.

The smolt tagging initiative alone has taken an army of people and and a huge amount of funding and technology to accomplish. And this is just the first basic step (albeit a very impressive first step considering the work required)

Take the finding that 50% of smolts make it to sea. That single piece of information could take years to verify if the 50% is normal or non-normal. 50% might be the historical normal for migrating smolts. In that case all that effort has gone into finding out that there are no in-river problems with smolt migration numbers, and that FEBs and other predators are having no effect whatsoever on stock levels. Valuable learnings but back to square one. And that is just one single factor.

Maybe, maybe, maybe. . . . a lot of maybes, and very difficult to estabish the historical norm if this is the first time such a study has been undertaken.

'50% of what?' might be one question we need to ask. Maybe we should we start with establishing the number of deposited eggs as a baseline. As we all know, it is a lifecycle we are studying so where in the lifecycle is the best place to start? Maybe signal crayfish are eating all the salmon eggs, after all crayfish numbers are increasing whilst returning salmon are decreasing. Again, maybe, maybe, maybe?

And remember, correlation does not always mean causation. Just because the increased number of FEBs directly correlate with the reduction of returning salmon (if that is even true), the two things may just be coincidental

As an example, its well known that the number of murders committed in Manhattan is directly proportional to the sales of ice cream (fact)! I.e, as the number of ice creams sold increase, the number of murders committed also increase. Should we draw the conclusion that ice cream contains a chemical that triggers people to commit murder? Or is it that more murders are comitted in hot weather because people are more irritable. Maybe its not even the ice cream eaters that murdering people, so, although the two things strongly correlate, they are more likely to be coincedental? Who knows.

The test methods may also be flawed (the tags may cause clinical mortalities, may attract predators, may affect the ability of the smolts to escape predators and so on)

I suppose that, through these ramblings, I'm trying to point out that such an investigation is super complex, and has a vast number of variables that all need to be studied, and this all takes a long time. It could easily take 10 years just to narrow down the number of variables

I'll bet that we on this forum alone could list 100 potential factors in the collapse of salmon stocks (warmer sea temps, moving of the feeding grounds, super trawlers, synchems, FEBs, fish farms, no food in the oceans etc etc etc. . .), I'll also bet that it wont be a single factor which makes it even more complex to find root cause.

I for one, am glad that someone has started doing this work, as, apart from us, who is actually interested in the demise of wild salmon?

The only way to understand this great mystery is by a scientific approach. That will take time, but I've always believed that the most important thing about making a start, is making the start, and I for one am grateful for that.

* ps the references to FEBs is just an example, insert any potential root cause of your choice :)
 
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MCXFisher

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I hope this doesn't sound pompous, but thank you Alan T for a well-considered and balanced contribution to the debate - a pleasure to read.
 

mows

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ken whelan.png

Fair points Alan,

But I always come back to this picture and question the impartiality of the science.

A problem with as many potential causes such as this is immensely complex, and thus costly and time consuming to reach any kind of robust conclusion

I dont think the scientists are particularly drip feeding information, I believe that this is just the rate of progress in such a large project.

The smolt tagging initiative alone has taken an army of people and and a huge amount of funding to accomplish. And this is just the first basic step (a very impressive step considering the effort required)

Take the finding that 50% of smolts make it to sea. That single piece of information could take years to establish the cause. And even then, 50% might be the historical 'normal' for migrating smolts, so maybe all that effort has went into finding out that there is no in-river problems with smolt migration, maybe FEBs and other predators are having no effect whatsoever.

Maybe, maybe, maybe. . . . and very difficult to estabish any historical norm if this is the first time such a study has been carried out. 50% of what might be the question we need to ask, should we start with establishing the number of deposited eggs as a baseline, as we all know, it is a lifecycle we are studying so where in the lifecycle is the best place to start?

And remember, correlation does not always mean causation. Just because the increased number of FEBs directly correlate with the reduction of returning salmon (if that is even true), the two things may just be coincidental

As an example, its well known that the number of murders committed in Manhattan is directly proportional to the sale of ice cream (fact)! I.e, as the number of ice creams sold increase, the number of murders committed also increase. Should we draw the conclusion that ice cream contains a chemical that triggers people to commit murder? Or is it that more murders are comitted in hot weather, so by chance, the two things correlate. Who knows.

The test methods could also be flawed (the tags may cause clinical mortalities, may attract predators, may affect the ability of the smolts to escape predators and so on)

I suppose that, through these ramblings, I'm trying to point out that an initiative such as this is super complex, and has a vast number of variables that all need to be studied, and this all takes a long time. It could easily take 10 years just to narrow down the variables

I'll bet that we on this forum could list 100 possible causes of a collapse in salmon stocks (warmer sea temps, moving of the feeding grounds, super trawlers, synchems, FEBs, fish farms etc etc etc. . .)

I for one am glad that someones doing this work, as apart from us, who is actually interested in the demise of wild salmon?

The only way to understand this great mystery is by a scientific approach. But that takes time, and I've always believed that the most important thing about making a start, is making the start, and I for one am grateful for that.

* ps the references to FEBs is just an example, insert any potential cause of your choice :)
 

AlanT

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I hope this doesn't sound pompous, but thank you Alan T for a well-considered and balanced contribution to the debate - a pleasure to read.
Thanks Michael, I normally dont have time to contribute to the longer threads but trying to point out that this is a problem of epic complexity. I hadn't noticed your response, our thinkings are similar.

The salmon lifecycle adds complexity as in that its cyclic, where do you start (number of deposited eggs, number of returning adults, number of migrating smolts. . . . . ?), as I say, making the start is the most important part.
 

AlanT

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Fair points Alan,

But I always come back to this picture and question the impartiality of the science.
I agree, unfortunately there is always that risk.

Hoping that if the data is being published as the project progresses then it will be easier to challenge any conclusions. All we need is honest reporting of the facts along the way.

Ps. Im not challenging anyones thought processes or beliefs as none of us know, just pointing out that finding out the root cause(s) will not be an easy one and will take time. A long time.
 
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