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Thread: Smolt tracking

  1. #21
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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
    Last edited by AlanT; 27-11-2019 at 08:27 PM.

  2. #22
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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.

  3. #23
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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.

    Quote Originally Posted by AlanT View Post
    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

  4. #24
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    Quote Originally Posted by MCXFisher View Post
    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.

  5. #25
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    Quote Originally Posted by mows View Post
    ken-whelan-png

    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.
    Last edited by AlanT; 27-11-2019 at 08:14 PM.

  6. #26

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    Some good points.

    It's probably worth noting that at the 2017 Source to Sea meeting a fish tracking expert from Durham University suggested that 'lost' tagged smolts should be ignored - simply because of the potential impacts of tagging and nothing is known re their fate. The take home message therefore seemed to be to avoid wild speculation and focus on those fish that 'make it' through the monitoring zone(s).

  7. #27
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    Attachment 40947

    40,000 dead smolts in two weeks,100m from one of the finest sea trout spawning burns(historically).

    And the FHI response.......well within mortality limits. Nothing to worry about.

    Dearie me.....or worse.
    Attached Images Attached Images 75567319_10218327505997482_42346779810725888_o-jpg 
    Last edited by innes; 27-11-2019 at 08:29 PM.

  8. #28
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    Quote Originally Posted by innes View Post
    Attachment 40947

    40,000 dead smolts in two weeks,100m from one of the finest sea trout spawning burns(historically).

    And the FHI response.......well within mortality limits. Nothing to worry about.

    Dearie me.....or worse.
    Sorry, no attachment showing

  9. #29
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    Quote Originally Posted by innes View Post
    Attachment 40947

    40,000 dead smolts in two weeks,100m from one of the finest sea trout spawning burns(historically).

    And the FHI response.......well within mortality limits. Nothing to worry about.

    Dearie me.....or worse.
    Where is this Innes?
    Your attachment doesn't work?
    Respect My Authorita!!

  10. #30
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    75567319_10218327505997482_42346779810725888_o-jpg
    Last edited by innes; 27-11-2019 at 08:30 PM.

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