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Salmon - Are we doing enough with the information we already have?

After the blog of a few day ago, the one relating to the great many in-river problems associated with the reduction in salmon stocks in the North Atlantic, I had an interesting conversation with Colin Carnie. Colin is Civil Engineer with much experience working on various Scottish rivers. I was extremely interested and enjoyed reading his detailed and educated response to the blog. I'm sure you will be too -

Ian Gordon

You may recollect that we met a few years ago when I gave you a copy of the management plan I wrote for the River Deveron as an example of the work I was then currently doing. My workload is now pretty minimal – all of the rivers have able biologists (I’m a civil engineer) and managers who can do much of the work I was doing.

Inevitably I am alert to the present problems of declining stocks and the initiatives being undertaken to try to reverse this situation but I share your view on where the emphasis ought to be placed. Of course i recognise that this is a multi-valent problem and it is most unlikely that with the best will in the world we can tackle all of the causes of decline but it seems nonsense to me to committing funds towards hugely expensive research studies in the high seas when we can do b,gg,r all about them. We can do something about the freshwater life stages and that is where our efforts should be directed. I set out below some of my thoughts which I hope you will find supportive to your own efforts.

Firstly there is some good news:

My home was in Kilmacolm which has always been my base tho’ I have wandered and presently live in Fife but I grew up fishing the headwaters of the Gryffe and its tributaries, fishing with total access to wonderful streams, worms, flies and freedom! Two aspects of my view of the problem arise from those early experiences. It was war time or shortly thereafter and I caught trout on almost every occasion I went out. Now a youngster has to work very hard to catch a single trout

At that time, and for many years thereafter there was a total barrier to migration on the Gryffe at Bridge of Weir as well as serious pollution from the tanneries and further downstream from human and industrial pollution which would have stopped any fish entering the river. Some 50 years later I owned a house in Kilmacolm with a garden running down to the Gryffe and my usual walk with my dog was along its banks. Only one thing could have given me greater delight on finding a dead kelt would have seen when it was alive. Now the Gryffe has a recognised run of salmon. We have really seen quite remarkable improvements in our “industrial” rivers – look at the Clyde, the Almond, the Midlothian Esk, the Denny Burn, and one could go on. We have improved the quality of our rivers with all of the available official powers, starting during the era of the River Purification Boards with the powers they had, the legislation that gave them the powers and the inputs from local interests. This has continued today to much appreciation amongst a wider public than just the anglers. Great progress, and in these situations we are handing our rivers and streams to future generations in a better condition than we inherited them. Recently I went to see a short pool-and-traverse pass which had been built (I suspect at enormous expense) by SEPA on a quite small stream a tributary of the Gryffe. Expensive, but deemed to be worthwhile.

Secondly the bad news:

Living in the west where salmon and sea trout fishing was more appropriate to my father’s pocket (and latterly mine) so that was where we fished in the rivers and lochs. I have fished for many years for at least a few days every year on the River Awe – for a 50 year period I only missed one year when work took be abroad – and prior to that there were annual visits to the River Ailort (for me) and Loch Eilt (for my father and his pals). It pains me now to think of the catches from the loch where sea trout were treated like salmon as largely single spawners without the knowledge that they were multiple spawners. More recent knowledge of Loch Eilt and Loch Shiel have shown that the fears of stock collapse expressed some 25/30 years go have very sadly been buried in political morass. So stocks have simply disappeared. We are passing these rivers, streams and lochs on the West Coast on to future generations in a worse condition than we inherited them. I have no doubt that sea lice have caused the particular problem in the rivers and lochs of the West Coast but when you see what Bob Kindness has done for the West Coast Carron you immediately see what can be achieved. The West Coast is still more wild and natural and land use is very much less intensive than in the rest of our country so the options for improving stocks are more readily identified.

As you point out there is a huge list of problems for all of our salmon rivers apart from the special damage being done on the West Coast and this is an inevitable and typical consequence of a multivalent problem in the natural world. The challenge to objectors is the usual problem of proving a negative. I know little about the conditions and dangers at sea and do not want to comment on them. However I have done considerable work on the freshwater stages of the salmon’s life cycle, recognising that my skills are in engineering - hydrology, hydraulics and structures - so conditions from the watershed to the estuary are within my gambit. I hope that the following comments may be of some interest to you and may help to determine priorities.


Changes in land use in our catchments is hugely significant because of the impact it makes on the hydrology of the upland burns, streams and the lower courses of rivers. I learned to fish in a burn which subsequently flowed into the Teviot and then Tweed. I caught small trout which I kept on the basis that I would gut and eat them – but were they parr? I simply do not know but I have subsequently walked this stream and it may be possible that salmon and sea trout have spawned in it. Today it, like others in the Tweed catchment, dry out in the summer so neither trout nor fry nor parr survive.

Upland drainage, afforestation and improved grasslands have all been hugely subsidised in the 50s and 60s and all have ensured that water flows off the land more quickly. Naturally the farmers drained the wet and boggy parts of their land – the areas which acted as reservoirs for gradual run-off. In the Tweed catchment of some 4500 there has been a change 1500 from land which retained water to land from which water drained more rapidly. I don’t know what the figures are for upland drainage and improved grasslands but they are probably similar in the catchments of the Nith, Deveron South Esk and Helmsdale. Afforestation is more widely spread and its impact will certainly apply in the other three big rivers.

As a civil engineer I am delighted that a significant number of manmade barriers to migration have been removed but I am embarrassed by the number of barriers built in the second half of the 20thC which are still in place. The development of hydro-electric power was hugely important in the post WW2 era and, as we face the problems of climate change, they are equally important today. Similarly, water supplies for domestic and industrial uses have grown as the population has grown and, very properly domestic needs have increased and standards have been raised. The provision of access to the upper Garry is to be welcomes but there are still rivers and streams where dams were built expressly to prevent upstream migration. We now know better how to manage the relationship between these social and economic needs and the ecology of our rivers and lochs. It is a matter of the urgent need for action.

Middle Reaches

We have flooded considerable lengths of rivers behind great dams, losing substantial km of spawning and nursery streams. Look at Megget or Lyon where we have very purposefully stopped migration or the glaring example of the Perthshire Garry but there are other hecks such as at Glascarnoch and Vaich on the Conon system serving the same purpose. A low dam on the K of S Carron is specifically designed to prevent upstream migration. Jock Menzies, the fisheries officer of the NSHEB, recognised the impact of lost spawning and nursery areas in the Tay catchment and was instrumental in opening up the natural barrier at Craighall Gorge on the Ericht. As a result, for many years now the Ardle and the Shee have made a significant contribution to the stocks in the Tay system.

At least part of the problem was screening intakes to prevent parr being drawn into turbines but screens have improved and in some cases this problem should not arise

Lower Reaches

It seems to me that our knowledge of smolt migration is rather limited with the associated danger that current estimates of historic smolt numbers are built on a very weak foundation. The best record that I know of providing quantitative information is from the North Esk where in Willie Shearer’s book he shows a graph of smolt numbers. The interesting detail is the decline after the first year of sampling. I do not know whether this was an anomaly or part of the previous pattern but if it was the latter, it’s a bit of an eye-opener. (I seem to have mislaid my copy: otherwise I would have copied it to you).

When I was working on the Dee; the late Major Foster of Park made the point to me in the late 1970s (I hope I have dates correct) that he used to see both sides of the Dee black and sparkling with shoals of smolts in enormous migrations downstream. “Now I never see them” were his words. The same description was given to me by a boatman on the lower reaches of Tweed

2. Water Chemistry

2.1. Acid rain is unseen but in so many places where pH is or has been measured it is much

more acidic than most people would anticipate. Some years ago I attended a conference on the Dee where in his closing remarks he stated “well at least we know thet the water quality in the Dee is very good”. I had to point out that at the water treatment works at Inchmarlo they occasionally took readings of pH of less than 5.5. It only requires a flush at that level of acidity to destroy alevins. It is not without reason that virtually every commercial hatchery which the salmon industry runs on the west coast has facilities to feed lime into the intake stream to raise the pH.

2.2. There are lots of examples but the one I rather like occurred years ago in Galloway when

the Galloway Trust installed a pH meter which produced high levels of acidity which

SEPA would not believe. Subsequently they installed a meter and were dumbfounded

when they recorded the same figures. It seem to me that acidity is one of these ‘out of

sight/out of mind’ problems which does not get the attention that it deserves although there is a great deal of recorded information.

I was preparing a management plan for the River Wick which is an extraordinary little river coming off the Flow Country. One upland stream flowing from a small loch in the peat had a pH of 4.8 - very acidic - and some 3 km downstream after flowing over the slate slabs it had changed to 7.75 - pleasantly alkaline and slate is not nearly as reactive as limestone.

2.3. I know some work is being done on this but I do not see any signs of improvements in our upland streams.

2.4. You are much more knowledgeable about water chemistry (particularly Inermectin!) but I am reminded of the comment by one Spey fisherman who was concerned about the total lack of March Browns in the river perhaps 20 years ago. There is no doubt that there is much less insect life in our rivers and lochs than there used to be. SEPA will quote BMWP showing how healthy the invertebrate life is but the scoring system does not go back very far. Incidentally I think that the base lines for electro-fishing of juvenile densities suffer from the same limitation.

The West Coast and sea lice.

The problems of the West Coast sea trout but also the salmon, have been played out to the point when most people who have campaigned over the last 30 years for some sort of resolution have dropped by the wayside out of boredom or have fallen off their perches so I will not labour this point. Even the AST has recognised that the science clearly demonstrates the link between decline in stocks, sea lice and industrial salmon farming. The political pressure has been there for at least that period going back to the work of the Govt’s Salmon Advisory Committee when the intransigence of the civil servants prevented members of the committee to be critical of the industry. .

What I would say however is the need to look at the undeniable success of the West Coast Carron where they only have “good years and very good years” – I quote Bob Kindness.

The one part of the problem of lower stocks which is under our direct control is in freshwater and the production of smolts. The above examples cover factors which reduce the number of smolts produced naturally in our rivers and the necessary science to support improving the number is in place. I am a staunch supporter of the need for science based evidence and I accept the approach generality of genetic dangers but where in our river systems is there genetic purity? Char have not been stocked and clearly there are a number of distinct populations in some lochs as well as distinct populations within the water bodies of some lochs and we should fight to ensure that they don’t get messed about. In 1847, T T Stoddart wrote about the clear and distinct differences between the trout in the various tributaries of Tweed but this did not continue below Kelso colouring and shapes were mixed. Hatcheries have been the source of trout since the 1870s (Howietoun hatchery was established in 1873) and with many others later on there must be few fisheries which have not had introductions of fish. Stormontfield on the Tay started in 1884 was the first salmon hatchery but they have also proliferated throughout the country. Most of them have been related to their own rivers but some have hatched ova from other rivers. For example the Duke of Sutherland created a hatchery on the Brora which Archibald Young reported in 1887 was hatching ova from the Brora, Thurso, Helmsdale and the Rhine. The hatchery at Huningue near Basel was probably the first large hatchery in Europe. The NSHEB established two very large hatcheries at Invergarry on the Garry and at Contin on the Conon and from there distributed juveniles quite broadly. So are we being rather po-faced about hatcheries? I rather think so. Bob Kindness brought ova, or maybe broodstock – I’m not sure, Loch Coulin (Ewe system) to establish his operations on the west coast Carron, and did this with the blessing of a fisheries scientist. I think it is time that we brought some pragmatism into the whole debate of the use of hatchery operations. I think it should not should not go as far producing smolts and it should try to use local broodstock but where they are not available then other sources should be used.

CGC 7/4/2020

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