Smolt trap update: week ending 29th April and other news

Another trip south to check the smolts traps this morning. It was yet another chilly day, has there been a warm day this year? But the burns had dropped and the traps were fishing fine.

There were 11 salmon smolts and a single trout in the Truim trap, hardly worth marking such a small quantity, so they were measured, the 10th one scale sampled then released on their way.

The Truim smolt trap catch this morning

The Truim smolt trap catch this morning

The Tromie was better with about 150 fish in the trap, the best haul so far this year. 92 of them were unmarked salmon including quite a few small 1 year old parr, the smallest of which was 48mm. I have a lot of respect for these small parr, they have survived the first year and I know from scale reading in Ayrshire that fish like that can grow very quickly in the next year(s) to make good 2 or 3 year old smolts.

Some of the Tromie catch this morning

Some of the Tromie catch this morning. The small parr are in the left bucket; they are too small for mark and recapture work. Also in the left bucket are the previously marked and now recaptured smolts. The right bucket contains some of todays marked fish.

On a Monday we mark the smolts in a different position from that used during the rest of the week. This morning we were still catching some of the smolts released back upstream last Monday. The Monday release point is 2.7km upstream of the trap. 11 of last Mondays marked smolts were recaptured during the week, 5 on the next day but there were 2 yesterday and 2 today. At a few hundred metres per night this is a slow migration; there are about 130km to the sea from this point. All of this suggests to me that the main smolt run is yet to happen. The highest river temperature recorded at the traps so far this year is just over 5oC, my hunch is that there will be a big run as soon as the temperature rises.

After the smolt traps it was back to the office to work on my London presentation before a dry run this afternoon. I have some work to do now with some final tweaks but almost ready to go.

And to end another busy day I was shown a video in which I was named checked; several times, by Hilter of all people. See you in court Duffer!

There are 16 comments for this article
  1. Dougie Ross at 9:25 pm

    Hi Brian.
    I think you have put my last blog comment in the wrong place. It is relevant to what Jock, wrote and therefore should be put after it. Many thanks.
    KR Dougie.

    • Brian Shaw Author at 8:34 am

      Dougie, comments can’t be moved easily. If you want to reply directly to the previous post then please do so and I will delete your original. However I think readers will get the jist.

  2. Dougie Ross at 7:37 pm

    Hi Brian,
    Surely the 2012 figures, smolt figures that you have on file only prove with absolute certainty that the ‘environmental conditions’ you mention above have suited the smolt trap. How can we be assured that production has indeed increased in these areas without sufficient trapping data. We cannot stray from facts!
    KR Dougie.

    • Brian Shaw Author at 8:29 am

      Hi Dougie,

      Last years smolt trap results were good, that is a fact; good in a highland context and good in comparison to the previous years surveys. I hope you are able to accept the results on that basis. The next step then is to figure out why? If the good smolt production in 2012 wasn’t as a result of the mild winter/warm spring then the only other plausible explantion is that there is good smolt production each year but that the trapping conditions in other years haven’t allowed us to quantify that properly. That would be an even better situation but not a claim that can be safely made.

      It is not my job to “stray from the facts” I only work on the evidence collected. But it is in the nature of scientific research to seek explanations based on the figures and analysis. I would have been more open to criticism if I had claimed there was high smolt productiuon every year, we simply don’t have the evidence for that. Everything points to an actual increase in the smolt production in 2012, the justification for which I presented in the smolt trap reports. You may not agree with my analysis, if not please present your own?

      • Jock Royan at 12:10 pm

        Hi Brian,

        I agree that there is clear evidence that smolt trap results were excellent last year however that was purely down to the excellent trapping conditions in March. That’s the answer to your first why.

        What factual evidence do you have that 2012 smolt production was any better than previous years? Further more, considering the relatively poor trapping conditions so far this year, how can you quantify smolts production without supporting trap data?

        My view is that we were able to gather valuable data in 2012 due to the excellent trapping conditions. Whether smolt production was significantly better than previous years, only time will tell. If however there is no significant increase in the Grilse this summer or salmon in 2014, I suppose marine mortality or predation can be blamed.

        I have been very concerned about smolt output since I began at Kinermony and really do hope that you are correct that the 2012 smolt output was a good one. The evidence should show up in the next few years catches.

        • Brian Shaw Author at 6:56 am

          Jock, I detailed the reasoning for concluding that the 2012 smolt trap results were due to improved smolt outputs in the 2012 smolt trap reports e.g. pages 15 and 16 of the Tromie 2012 report, which can be found in the publication section of the website. A table showing the number of trap operational days in each year was included, I can’t post pictures in the comments section otherwise I have shown it here.
          It is good that you are concerned about smolt numbers, although who isn’t? Can I ask in all your time at Kinermony during which years did you observed better smolts runs or did your guests hook more smolts?

          • Jock Royan at 9:57 am

            Hi Brian,

            I began in 2006 and that spring, I was immediately concerned with the lack of smolts. Many of my guests were Sea-Trout anglers as well as myself and it was clear that in comparison to my early days of sea-trout fishing on the Spey that there weren’t nearly the same number of smolts being intercepted during their migration.

            2007 appeared to be a far better year but since then, they have appeared pretty thin on the ground.

            Purely from a riverbank perspective, my reason for labouring the point with regard to better trapping conditions instead of increased smolt output is that not many upper-middle river ghillies noticed any increase.

            I’ve heard all the high water masking the smolt migration arguments so I’m afraid that the only evidence I will accept with regard to such an increase in the smolt production is a directly proportional increase in the rod catches.

          • Brian Shaw Author at 6:52 pm

            The reason I ask is that since the 1990 smolt run there have only been 6 smolt years/runs that have returned rod catches of over 10,000. Included were the 2004/2005/2006 and 2009 smolt year classes. The other two good smolt year classes were 1992/1993. We know that the marine survival for the 2009 smolt year class was good but generally poor in the early 00s. However using your suggested correlation with rod catches there should have been good smolt runs in those years?

  3. henry spence at 4:21 pm

    Brian, will a copy of the presentation given at the London meeting be made available for those of us that were unable to make it?

    • Brian Shaw Author at 4:47 pm

      Henry, yes that is the intention, I will post them all on the website next week. Sorry you couldn’t make it.


  4. john harris at 12:51 pm

    Thanks for your London presentation Brian

  5. Olivier Devictor at 6:54 pm

    Brian your London presentation was excellent and i know ”my ” River Spey much better now.
    Many Thanks

  6. Charlie Harman at 6:19 pm

    Hi Brian,

    First of all thank you and the rest of the team for your very informative presentations at last night’s London meeting. I hope you all felt it was worthwhile – it certainly seemed to be well received.

    I have a question about smolt production. The results from the 2012 smolt trapping on the Truim and Tromie are very encouraging indeed – and I hope they will lead to increased numbers of grilse in 2013 and 2SW fish in 2014! But a rise of nearly 100% in the Tromie’s output (according to your Petersen Method Estimate) compared to the average of preceding years, and well over 100% on the Truim, seems a remarkable increase and I wonder if you had any explanation for it? In the case of the Tromie, there’s an increase in 3 year old smolts, which might account for some of this increase, but not all of it. I see that there was also an increase in parr numbers in the mainstem (per your graph on page 44 of the annual report) between 2010 and 2011, and these presumably would also mainly have smolted in 2012, but it’s hard to tell if it’s of the same magnitude – and incidentally I’m glad to see that 2012 saw a further increase!

    This partly ties in with the question I asked at the meeting about whether there is any objective way to assess how the river is performing as a smolt factory against its potential, rather than simply comparing its performance to that of your neighbours. Was the 2012 output unusually good for some reason, and are the previous years’ figures more in line with what you would expect, or do you think these tributaries should be putting out 0.6-0.8 smolts per sq. m every year? If so, is it possible to identify the causes of the previously low figures? Or if it is 2012 that was abnormally high, what could have caused that big increase?



    • Brian Shaw Author at 10:33 pm

      Hi Charlie,

      Thanks very much for coming along to the meeting last night, great to see yourself again and put faces to so many others.
      In the smolt trapping reports I mentioned the conclusions of studies on smolt production in Ireland. Correlations between many factors and smolt production were assessed. On factor positively correlated with smolt production were mild winters/springs. Last winter and spring were very open with exceptionally warm March weather. In trying to model smolt production we factor in 50% overwinter mortality to the autumn parr densities. If the overwinter mortality in mild winter/spring conditions is lower then higher smolt production could be expected. By the same reasoning we could expect lower production this year?

      When we do the fry index surveys in the mainstem the parr are very much of secondary concern, in fact if we are finding many of parr we are surveying in the wrong place. However I suppose that applies every year. We will try and quantify the parr density in the mainstem this summer. I am also very interested in their condition factor over the course of the year. Work to be done there.

      I dislike that term “smolt factory”, almost as much as the “the river is dying from the top down”! Factory suggests automation, control, consistency, etc whereas a salmon river is only part of a complex ecosystem subject to huge variation from year to year. Anyway good to get that of my chest!, but I can see that it is an anology that many can relate to. My feeling is that the 2012 smolt production from those tributaries were good, I’d expect the average to be less than 0.5/m2. However it was great to have the 2012 results on file, even if only as a marker of what can be produced when environmental conditions are favourable.

      Those that have known the Spey over the years consider that the Truim in particular is exceptionally good for an upland tributary. The conducivity is considerably higher than adjacent tributaries (I am going to establish why this summer)and there is a great deal of good juvenile habitat and spawning beds. The flow is also regulated and although there is a large loss of water through abstraction, the base flow is slightly elevated, that may also be a helpful factor.

      bed time,


      • Jock Royan at 6:15 pm


        At last May’s Spey Foundation meeting, you agreed that the smolt figures from the Truim & Tromie traps, had been affected by the excellent climatic conditions last March. Later in the year, the emphasis on the excellent smolt figures had shifted to an increase in production assisted in part by climatic conditions. I look forward to discussions at the next Foundation meeting & your estimate on this year’s production considering this years trapping conditions!

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