Bertha leaves her mark

We were promised a wet and windy night from the tail of Hurricane Bertha and she certainly delivered. Looking at the river level websites it appears as if the whole of the Spey catchment was affected by heavy overnight rain and strong winds. The local burns at Knockando were very high this morning with the Spey mainstem still rising until about 12 noon. In the Aberlour area the river was up on the floodplain with some of the locals saying it was as high as they had seen. The river was transporting a huge volume of debris downstream, mainly tree trunks and branches, along with all the other accumulated debris from a couple years of relatively low water.

The Spey at Aberlour, hopefully it will peak soon.

The Spey at Aberlour, the river level here peaked at noon.

The weeks of nice summer weather experienced in July must seem a distance memory for some already. The farmers took advantage and made hay but these bales will probably not be much good now.

Make hay whilst the sun shines!

All that hard work for this

On the walls of one of the old railway line underpasses in Aberlour there are marks showing the levels of previous flood events. The Nov 2000 flood level was exceeded this morning although it would have to rise another 18″ to reach the July 1970 level.

Historic flood levels on an Aerlour underpass

Historic flood levels on an Aerlour underpass

This is my third year here and this is by far the biggest flood event in that time. The fishing will be out of action for a couple days for sure but of greater concern is whether these big flood events have any significant impact on juvenile fish stocks in the river. We have recently surveyed the mainstem using the timed electrofishing protocol so if we get the chance, and assuming that river levels drop back sufficiently, it would be good to repeat some of these sites to re-assess salmon fry numbers. I spoke to one of the ghillies at the lower end of the river this morning and whilst the river was still rising down there it wasn’t yet at the level of the 2009/10 floods. Looking at the history of flood events it is remarkable how often August features in flooding records; it is a month that can deliver intense rainfall.

However, it is never all negative with these things and the Ranunculus will hopefully have taken a hammering; as will other invasives such as himalayan balsam which have been spreading over some of the river gravel bars. We can only hope that not too much damage has been done to our juvenile fish stocks and other wildlife along the river.

There are 15 comments for this article
  1. Charlie Herd at 4:59 pm

    Brian,
    Recent empirical evidence has told us that juvenile stocks are generally worryingly low, adult stocks are even more worryingly low and serious damage has been inflicted on the already low juvenile stock by the recent flood. Meanwhile you tell us that the Board stocking sub-committee has concluded that stocking is too risky and expensive and all that is going to be done is yet more fruitless research.
    There is plenty of evidence from other rivers which shows that mitigation stocking can be successful, why is this evidence is being ignored ? The situation is serious enough for the minutes of the sub-committe’s meeting to be made public to let everyone see how and why they arrived at their conclusion. Are these minutes available online ?
    Regards,

    Charlie.

    • Brian Shaw Author at 6:09 pm

      Hi Charlie,

      I will check with the powers that be regarding publication of the Stocking sub-committee minutes.
      In the meantime we wait for the river to drop low enough to carry out some more meaningful research on the actual impacts of the spate on juvenile stocks. I, and the Spey Fishery Board, regard that as a worthwhile use of research time and it may move the debate on a little.

      Regards
      Brian

  2. Grant Morrison at 7:37 pm

    Brian your response to a regular Spey angler Willie Mair concern is disappointing.

    I feel you were too vague about the juvenile mortality seen first hand by myself and the other ghillies at Delfur.
    On Monday evening between the bank of Otter pool and our track(which had become a flood channel) we found 25 juvenile fish (mainly salmon) in an area no bigger than 3 metre square. Since the river has dropped back we are seeing similar large numbers on our banks up and down the beat. In much of the area flooded there will no doubt be large numbers of dead parr and fry lying hidden under broom bushes, long grass, huge deposits of sand, branches and debris. We have watched the herons, gulls and crows ”clean up” many dead fish over open ground in the past 3 days.

    In my opinion the numbers of juveniles lost in such a cataclysmic flood event is far more likely to run into the hundreds of thousands if not millions. This is the second massive flood to effect the Spey in 5 years, in 2009 many of the ghillies on the river had serious concerns over the effect of such flooding on future runs of fish- these concerns were ignored, no action was taken to try to compensate for the losses at the time and we have potentially seen the result over the past 4 seasons. I cannot see how without maximising our hatchery output over the next few seasons we can have any other way of compensating our fishery for these huge losses? Our salmon are under more pressure at sea now more than ever- with your help we need to act now to ensure our rivers output is optimised, unlike some other rivers we have the ability, facilities, expertise and finance to do so.

    • Brian Shaw Author at 7:59 pm

      Hi Grant, you are right if you scale up the losses the number will be huge although difficult to put a figure on it. This issue was discussed at the quarterly Spey Foundation meeting today. We are going to monitor the mainstem as soon as it drops back to a height that will allow it to be surveyed in a comparable manner. The loss of the large parr I saw at Delfur is irreplacable; the survival rate of those through to the smolt stage would have been high so that will led directly to a reduction of the smolt output next year. The fry should have a greater capacity to recover from the loss, there is a high natural overwinter mortality every year, so the survival rate of those remaining will be better than it would have been. If I am right on that point; then the capacity of the hatchery to compensate for the loss of multiple year classes of juveniles from this spate is limited unless it held a stock of 1+ parr?
      There have been few studies on the impact of large floods on juvenile salmon populations, we have an opportunity now so lets wait to see what the findings are.
      In defence of my vagueness in the reply to Wilie Mair; as always on this river it is rarely possible to please everyone. Criticism arrives if anything negative is posted on the blog e.g. pictures of loads of dead juveniles but as you have taken the initiative on this issue I am quite happy to discuss.
      Thanks for the comment
      Brian

  3. Bryan Herbert at 5:04 am

    Hi Brian

    will you be doing the one of the fiddoch sites again as it had the highest number of juvenile fish so I presume it would give you a more accurate loss assessment as those sites had over 200 compared to the lower mainstream sites with very low numbers.

    Bryan

  4. Willie Mair at 10:41 pm

    I’d be interested in the survey as well with lower numbers found in most sites this year and the losses off of this flood it doesn’t look good for the future with fewer salmon in the river this year as well . Instances like this is where a back up could be used like a hatchery but I’m no scientist

    • Brian Shaw Author at 9:23 pm

      Hi Willie, our monitoring regime in the mainstem is something that I am proud of so this will be a good chance to use it to establish what the impacts have been. I saw dead fish on the banks of one of the lower beats today with lower number further upstream. Cumulatively the losses will amount to many thousands, possible 00’s of thousands which is a loss but one that is inevitable during these big spates. The use of the hatchery to hold reserve stock as insurance losses was discussed at the recent stocking sub-committee but the concensus was that the risks/costs outweighed the potential benefits. The events of the last two days haven’t altered my opinion on that issue.
      Rest assured that this opportunity to monitor the impacts of high water on our juvenile stocks will not be missed; providing the river drops enough before the end of Sept.
      Best regards
      Brian

  5. Euan Reid at 10:26 pm

    Brian, thanks for getting back to me. If we are concerned about the losses incurred from spates I think it would be interesting to review the mainstem survey sites after the autumn when the sawbills have taken the surplus of next years smolt run?

    • Brian Shaw Author at 9:27 pm

      Hi Euan, generally the surveys are done during the summer so we would have nothing to compare results collected after the autumn? Repeat surveys before the onset of autumn proper will allow us to compare with the earlier surveys.
      Best regards
      Brian

      • Brian Shaw Author at 10:05 pm

        Hi Euan,
        Feasible but it may coincide with a period whern there is a large mortality in the juvenile stock anyway and a change in their behaviour into overwinterinng mode. If we know how many birds there are it is straightforward to calculate the weight of fish consumed. As salmon are by far the most abundant fish in the mainstem they must form the bulk of their diet. I did this for another river once – frightening what they can consume. Brian

        • Euan Reid at 9:23 pm

          Brian,
          I would be interested to know how much they consume and with you having done this before you can tell me.
          I appreciate there must be a natural mortality at this time of the year but surely this loss could be reduced by not allowing them to be eaten by goosanders in large numbers on a daily basis.
          If you want to know how many birds there are then I’m sure we can give you a daily count through the mid October to mid January time which for me is the most decimating time for next seasons smolt run.
          Euan.

          • Brian Shaw Author at 9:52 pm

            Hi Euan, there are published figures for the daily consumption on predatory birds such as goosanders from which an estimate of numbers of fish eaten can be made. The key paper was published by Marquis and I will track it down. Daily counts would be useful supplementary information to add to our river wide bird counts. As you know we will be counting in Sept this year with a view to an earlier start for the sawbill licence from next year. After this weeks spate it would be good to know that there are some juveniles still around for them to eat.
            Brian

  6. Euan Reid at 7:19 pm

    It would be interesting to repeat some of the juvenile surveys as I’m sure as you are that we will have lost a huge number due to the flood.

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