I have long admired this report, which gives a pretty comprehensive view of the problems faced by the South Esk’s migratory salmonids in the 1950s. I have added my own notes where appropriate in an attempt to indicate where the differences with today’s South Esk lie. Of course the biggest change is the survival of salmon at sea. When Menzies wrote this report the return rate was probably 30% of all smolts leaving the river retrurning as adults. Today it is more like 5%. In due course I will add photos to this report to give a visual description of what is currently happening in the South Esk catchment.
Salmon Fisheries in the River South Esk
Report by W.J.M. Menzies
1. This report is concerned with the alleged shortage of salmon, or of salmon which take a lure, in the South Esk, the possible reasons for such shortage and any steps which can be taken to improve the position if the shortage exists.
2. The Report is based on my earlier knowledge of the River, on an inspection of all the main parts of the waterways on the 2nd, 3rd and 4th of December 1957 and on information supplied by Mr John Ogilvy of Inshewan, Mr G.G.J. Smart and Captain John de B Stansfeld, and Superintendent Donald Macintyre. Superintendent Macintyre accompanied me during the whole, and Mr Smart during part, of my inspection.
Topography
3. The South Esk is 49 miles long, rises at 3,300 feet and has a catchment area of 236 square miles. It has only one large tributary, the Prosen, which joins the main river at Downiepark; above the junction, the South Esk proper gathers probably 50% more water than the Prosen.
4. Montrose Basin near the mouth of the river provides an unusual feature in Scottish rivers, but probably has no direct effect on the movement of salmon.
5. Except in the extreme headwaters of the South Esk (the main River and the White Water) above Braedownie, the gradient throughout the river and in the Prosen is relatively easy, but there is a notable lack of banks of gravel of pea to cricket ball size. Such banks form the most favoured spawning ground of Salmon and are a feature of many important salmon rivers.
6. The South Esk above the Prosen Junction is very disappointing. At the top above Braedownie are two very rough streams, viz. The top of the main river and the White Water. The White Water is so steep, spate torn and denuded that any redds are extremely difficult to find, although 40 pairs are reported to spawn in it. Above the junction with the White Water, the South Esk is not quite so steep or denuded as the tributary, although it is still very rough when judged by ordinary spawning ground standards: about 160 redds have been seen in it. Owing to the effects, direct or indirect, of the very heavy spates which obviously rage at the foot of the hills, the survival rate of fry and parr here may be poor.
7. Below the junction of White Water and main river, the gradient is much less steep and more reasonable spawning ground exists, but only for a short distance, in which again about 160 redds have been seen. Like those higher up, nearly all those redds are probably formed by salmon.
8. This more reasonable section is a prelude to what is evidently an old lake bed extending for about 9 miles nearly to Gella Bridge. Although valuable holding water, this section is practically useless for spawning, the only really useful stretch being about 100 yards long in the gravel brought done by, and remaining in the mouth of, the Rottal Burn. In the whole 9 miles no more than 80 redds have been seen.
9. Below the exit of the old lake the river bed for four miles to Cortachy is predominantly rocky and less than 100 redds have been counted.
10. Another feature of The South Esk above Prosen junction is the paucity of tributaries. Other than the White Water, only the Rottal and the Moye are of any importance.
11. The Rottal may be regarded as being in two sections divided at Rottal Lodge. The upper section is chiefly occupied by sea trout. The lower section, about ¾ of a mile long, used to be much frequented by the medium class (12-15lbs) of salmon, but the channel has been “improved” for land drainage purpose, is now even and impacted, and in December 1957 only a very few redds, apparently of grilse or sea trout, were seen.
(Note: It is now recognised by SEPA that the Rottal Burn has been severely degraded as a South Esk tributary offering good juvenile habitat to both salmon and sea trout. The Esk Rivers Trust has applied for and obtained permission to restore the Rottal Burn to its eighteenth century course in order to improve both spawning and juvenile habitat. This innovative scheme in a SEPA priority catchment has the potential to recruit many more smolts with a genetic predisposition to return as adults in the early part of the year. The project will be implemented in 2012. Tony Andrews 16 January 2012)
12. The Moye Burn has falls about one mile upstream which at present impede salmon, although sea trout apparently pass them in considerable numbers, 500 sea trout redds being reported in the upper waters. The mile of water below the falls is rather steep and every rough, but about 70 salmon redds were counted in the pockets of gravel among the borders.
(Note. The Moy Burn falls have been improved and the whole Moy catchment is important for sea trout and some salmon spawning and juvenile habitat. Concerns about the impacts of sheep dip run-off should be in the past. TA on 16/1/2012)
13. In spite of the lack of the best type of gravel, a great deal of spawning ground exists in the Prosen and in the South Esk from the junction with the Prosen downwards.
(Note: This remains true. The Prosen tributaries, Uig(Lednathie), Crammie, Logie & Cally burns, are important for the South Esk’s salmon & sea trout stocks. TA on 16/1/2012)
14. In the Prosen this spawning ground consists essentially of small patches among larger stones and is generally in a rather hard type of bottom. But for fish production, the Prosen forms a complete contrast to the main river above the junction. Although no typical banks of spawning gravel are found, and occasional rocky reaches exist, patches of gravel used by fish are frequent almost throughout the whole length.
(Note: We need to take heed of these words because Menzies is giving us a focus here on the whole Prosen catchment and its importance to the South Esk catchment. TA on 16/1/2012)
15. The difference in the two streams is well illustrated by the count of redds. In the 15 miles of the Prosen about 1500 were seen in 1957, whereas in the 20 miles of the South Esk above the junction, only about 500 were counted. In the Prosen many were sea trout, but in the South Esk the majority were salmon; in neither the Prosen nor in the main river and its tributaries below Cortachy could the proportion of salmon, grilse and sea trout redds respectively be determined even approximately.
(Note: This contrast between the habitats of the Prosen and the South Esk above the Meetings may prove to be a crucial element as the Marine Scotland Science stock assessment project, starting in 2012, develops. It may prove that the Prosen is much more important than we have thought it to be. Tony Andrews January 2012)
16. Another contrasting feature of the Prosen is the number of side burns useful for sea trout and some grilse. Of these burns the Cally is outstanding as providing a relatively considerable amount of ideal spawning and feeding ground.
(Note. Again, we need to be aware of the potential within the Prosen catchment. Colin Gibb of Inshewan confirms the importance of the Cally Burn where brood-stock were collected by Donald Macintyre and himself in the 1960s. This area has, over the last five decades, been adversely affected by forestry planting too close the banks of tributaries and this has been or is being rectified. Tony Andrews January 2012)
17. The main river channel from Cortachy for about 20 miles down to Bridge of Dun is cut chiefly through alluvial gravel with occasional rock outcrops. There are good holding pools throughout. But much of the gravel is large and unsuitable for spawning fish. Consequently the spawning fords are well spread out and the feeding ground for fry and parr would seem to be relatively extensive. Over 700 redds were counted here, but in a wide river of this type the count may be less than the actual total: probably the majority were made by summer fish and grilse. Autumn fish, which would also spawn in the lower waters, are, as everywhere else, now very scarce.
(Note: This report was written in 1957 at a time, before the dams were dismantled and when the main runs of fish were in the spring (Feb to June). While the author’s comment on low recruitment of autumn salmon in the lower part of the main stem may have been true then, I suggest that, with the current predominance of autumn fish, the situation is likely to be different now. Recent observations suggest that the main stem of the river downstream of Cortachy provides extensive redds habitats for salmon and sea trout. We also concur with the author’s view on the extensive feeding areas for fry and parr in that part of the river, and, if anything, suggest that these areas may have become more extensive since 1957. Tony Andrews January 2012)
18. In addition to the burns already mentioned, two major, and several minor, burns enter the main water below Prosen junction.
19. The Carity enters just below Prosen mouth, and has over 600 redds, mostly sea trout in some excellent gravel, especially in an old lake bed in the upper reaches.
(Note. The dam was removed and the burn is much improved in terms of spawning habitat. TA on 16/1/2012)
20. The Noran has 10-12 miles of spawning water. The lowest section below the Brechin-Forfar road is certainly greatly over crowded with redds of apparently salmon, grilse and sea trout, and the upper part of the burn is said to be in a similar state. The survival rate of the fry is probably very poor, and if it were desired to establish a stock elsewhere in the district, eggs could be transferred from fish caught in this burn without any danger to the existing stock.
(Note: The dam at the Glenogil reservoir, built post 1957, has no fish pass, so the available spawning area on the Noran has been severely reduced. It may still be true that the lower reaches, just upstream of the confluence with the South Esk, provide spawning habitat. If there is an over-recruitment within the Noran it is likely that parr from this tributary migrate downstream to the main river, where there is ample fry and parr feeding habitat. Tony Andrews January 2012)
Obstructions
21. As a tribute to the easy gradient of the river and the prosperity of the countryside, the south Esk has always been noted for its mill dykes, all more or less formidable obstacles to the ascent of salmon.
One Dyke at Pearsie on the Prosen is modern and has an efficient salmon pass.
(Note: This dyke has now been removed. TA
16/1/2012)
The saw mill dyke at Cortachy is not a serious obstruction, but the right bank should be kept clear of large hand-placed stones.
(Note: The remnants of this dyke are still present. The level of the dyke poses no impediment to migrating fish but is maintained under SNH supervision to conserve an important freshwater mussel population in the lade. Tony Andrews January 2012)
Craigeassie dyke is a long structure set at an angle across the river with the complication of a double channel round an island immediately downstream of the dyke. It has an efficient pass at the top of the left bank channel, but only a rather difficult shute at the top of the right bank channel where the height of the structure is greatest.
(Note: This obstruction has now been improved to allow passage of fish at all river levels and water temperatures. The improvements were completed in the period 2000 to 2005. Tony Andrews January 2012)
The dyke at Finavon has been breached and poses no obstruction.
(Note: It should be mentioned that there were two other dykes between Craigessie and Aldbar. The Justinhaugh dyke was breached in about 1948 and the Finavon dyke in 1946. Both dams were of the ‘oldstone’ type and were unconcreted. Tony Andrews January 2012)
Aldbar Dyke, with a plain shute pass, when the water is at the right height, is not a serious obstruction except for late fish.
(Note: This dyke was breached in 2009 and no longer poses any problems for migrating fish. However, because the main part of the concreted section of the dam still stands a careful watch must be maintained to ensure that sharp edges do not damage ascending fish. Tony Andrews January 2012)
The dyke at Brechin bridge presents an obstruction to the run of fish, and a serious obstruction to late fish, but the plain shute pass has very recently been made more easy of ascent for fish.
(Note: this dyke was removed in the early 1960s. Tony Andrews January 2012)
Kinnaird dyke is a formidable obstruction at any height of water, and forms the key to the spring fish position. The poor pass has been considerably improved recently, and the new work is as yet not quite completed. Except when the water is too cold, the passage of fish should be considerably facilitated by this alteration.
Kinnaird Dyke in 1969
(Note: this dyke still poses a potential problem to the passage of fish. However, in about 1998 two baffles were installed on each side of the upstream entrance to the fish pass which, unusually, is located in the centre of the structure rather than on one side of it. The result of this improvement is a reduced energy flow through the pass, less turbulent white water and much easier passage to migrating fish in all but extreme conditions. We must monitor this obstruction, especially if the structure shows signs of deterioration. Tony Andrews January 2012)
22. Obstructions of less general importance also exist in certain of the tributaries.
Rather difficult falls exist about a mile above the mouth of the Moye Burn: a material improvement has recently been made here, and a little further work should make the ascent for both salmon and sea trout relatively simple.
A dyke near the mouth of the Carity is a serious obstacle to sea trout ascending to spawn but a bypass for fish around the dyke could easily be made.
Falls, not serious, at the mouth of the White Burn could readily be made less difficult.
Falls which stop fish are reported to exist near the top of the South Esk and near the top of the Noran, but in neither case is spawning ground likely to exist higher upstream.
Pollutions
23. Except possibly for discharges from sheep dipping tanks and small piggeries or dairy farms into tributaries, the only serious pollution originates from Brechin.
24. Sheep dipping tanks are an insidious, and often unsuspected, cause of damage. One discharge of perhaps only a few minutes duration can kill all the young fish in a tributary for a long distance below the outlet.
25. Brechin, at present, discharges all the domestic sewage and trade and gas works effluents without treatment other than very inadequate settlement of solids. The result is that even in November the entire bed of the river from Brechin down was covered with a profuse growth of sewage fungus: it was growing on the downstream face of Kinnaird dyke. Evidence of death of fish is lacking, but real danger must exist of serious mortality through lack of oxygen, owing to oxygen absorption by the crude effluent or through the decomposition of sewage fungus in warm weather. Evidence that the pollution deters fish from proceeding upwards is also lacking: evidence in other rivers (e.g Forth) suggests that they are not normally deterred by this cause.
(Note: I had the misfortune to experience the sewage effluent from Brechin during the years I fished Upper Kinnaird as the guest of the late Jock Leslie between 1974 and 1980. I remember the colour of the water had a greyish hue and there were some solids including faeces and strands of toilet paper in the river, often getting caught up on the line, cast and fly. Apart from the disgusting aspect of fishing in a sewer, I am in no doubt that fishing there was a health risk for both humans and salmon. This has now been resolved with the closure of the distillery and the construction of Brechin sewage works, although in times of extreme flooding Brechin’s sewage still gets into the river. TA 16/1/2012)
26. Salmon (probably only back end fish) actually spawn in the fungus infested reaches: only a special research could determine the effect of the fungus on the incubation of the eggs and the feeding of the fry and parr. Provided decomposition does not occur, it is not likely to have any effect on the migrating smolts.
(As in 25. above. Now resolved. TA 16/1/2012)
27. Brechin sewage works are being reconstructed, but at present only sedimentation tanks are being installed. Percolating filters, which form the second stage of the work, are urgently necessary.
Poaching
28. Poaching, although annoying, has hitherto been kept in check sufficiently to prevent any noticeable damage to the stock of fish. So long as present protective measures are continued, it is unlikely to be harmful to the breeding stock unless extensive Cymag poisoning were adopted.
(Last reported major cymag incident took place at Finavon on 17/7/1989. With value of wild fish increasing it is important to remain alert to the possibility of poaching making a comeback. TA 16/1/2012)
Netting
29. A considerable number of fixed nets exist on the coast to both the north and the south of the “estuary” as defined by the Salmon Fishery Acts.
30. Sweep netting in the river above the basin apparently ceased at the end of last century, except for a few years during the First World War.
31. During this century approximately three shots have been worked regularly in the basin, but only from June to the end of the season: they are (a) in the middle of the basin, (b) just above the railway viaduct (c) near the mouth.
(Netting in Montrose Basin ended in 1995 following the buy-out of the rights by the South Esk Angling Improvement Association. TA 16/1/2012)
32. Near the top of the basin an additional shot was worked in 1956 and 1957, but during the summer only.
(Ditto as for 31. above. TA 16/1/2012)
Predators
33. Seals have increased considerably in numbers in recent years and therefore take a greater toll of salmon proceeding to the South Esk but they are not likely to affect the stock significantly. Otters are reported not to be plentiful.
34. A breeding colony of 20-30 pairs of mergansers nest near the top of the basin, and, with cormorants, feed , up and down the river, as well as in the basin. About 200 cormorants are shot annually, rewards being paid by the district fishery
board.
35. A very large colony of black-headed gulls nest in Kinnordy Loch near Kirriemuir, and number are seen about the river.
36. Sea trout, both kelt and finnock, probably prey to some extent upon ova and parr, as well as upon smolts migrating through the Basin. The stock of brown trout, which may be predators on, as well as competitors for food with, the parr is said to be small.
Catch of Fish
37. The coast nets catch fish originating from the North Esk and South Esk; as has been proved by marking live fish, a proportion of the catch also originates from rivers further away. The number of fish caught is unknown, but, even if it were, the number of South Esk fish could not be extracted from the total. The incidence of netting here is not greater than, for instance, on the coast to the north and south of the Dee. Moderately intensive netting exists within the mouth of the Dee, very many times more intensive than within the mouth of the South Esk, and yet the Dee maintains a very large stock of fish. Intensive netting is also carried on within the mouth of the North Esk after the North Esk fish have run very similar risks to those which face the South Esk fish on the sea coast: yet the stock of salmon in the North Esk is reported to be at least maintained. Only marking on a reasonably big scale could prove the proportion of the fish coming to the coas which are proceeding to the South Esk. The coast nets must catch South Esk fish but, by analogy it would seem that the number so caught is not likely to be unduly harmful to the stock. The extension of the weekly close time by 6 hours in 1952 was intended to secure a larger escapement of fish but it is yet too early to estimate the results.
(Note: We still don’t know what proportion of the catch of the coastal nets ‘belong’ to the South Esk, but recent advances in radio tracking technology and genetics should provide the data within 5 years. TA 16/1/2012)
38. Unfortunately statistics of catch even in the river are extremely scanty.
(Note: catch statistics for both river -rods- and nets are much better, but still far from fully useful in terms of conservation management. The Government publishes catch figures for the Esk District about 11 months after the previous season has ended. TA 16/1/2012)
39. In the latter part of the nineteenth century, the run of salmon in the South Esk was, as elsewhere, predominantly in the summer and autumn, but the number then netted between Brechin and the basin, in conditions which should have been very favourable for the operation, was by no means impressive. Even in the nineties when grilse generally were so very abundant the number taken by these sweep nets was very small. During the First War, when netting at Brechin was resumed for six years, some spring salmon may have been included in the catch which, however, was not materially greater than that taken twenty years earlier. Grilse had dwindled to insignificant proportions, although at that period grilse were scarce everywhere.
40. I am informed that the catch made by the sweep nets in the Basin at the present time consists almost entirely of sea trout and that the number of salmon and grilse taken is insignificant: in any event these
sweep nets are not started until after the run of spring salmon has finished.
(In 1994 Noel Smart of Joseph Johnsons told Colin Gibb and myself that the 1994 season catch in Montrose Basin was about 250 MSW salmon, 600 grilse and over 2,000 sea trout. 1994 was the last year of net & coble fishing in the Basin. Soon afterwards SEAIA bought the rights to fish in the Basin. TA 16/1/2012)
41. Throughout this century the number of sea trout caught by net has steadily improved: figures show that in recent years the population has been double that of 1900-1909 and that a quite exceptional run in 1957 was over three times that of the earlier average.
(The Usan nets agreed to return all sea trout from the 2010 season in return for compensation. TA 16/1/2012)
42. The collection of record of rod caught fish ceased in 1939. Figures, not complete, are available only for the years 1928-1939. During the last nine of these years, in which the figures were reasonably complete, the total catch varied from 400-700 fish (except in a very dry year when it was only 200). Statistics of rod caught fish everywhere are sadly deficient and from comparable rivers are lacking, but assuming an angling length of 20 miles in the South Esk, the number of salmon and grilse caught appears to be small.
43. Of the total catch of salmon and grilse throughout the river in 1931-39, 60 per cent was taken before 15th June. The comparatively short stretch below Brechin, of which by far the most important part is from Kinnarid dyke downwards, had 55 per cent of the total. On the other hand, 82 per cent of the sea trout (excluding finnock) were caught above Brechin: in 1938 and 1939 the sea trout numbered over 1000 as compared with 500 to 800 in the earlier years.
(Note: It is worth looking at the Finavon records of sea trout catches for 1938/9. Most S Esk sea trout were caught at Cortachy, Inshewan, Finavon and Aldbar/Kintrockat. TA 16/1/2012)
44. A surprising feature of the statistics is the scarcity of grilse, these small fish providing only 3 per cent of the total rod catch of salmon and grilse. To what extent this result represents the stock of grilse may be open to doubt although clearly the proportion of grilse is out of line with the amount of spawning ground suitable for, and to an uncertain extent used by them. Before netting ceased at the end of last century, when grilse in Scotland were plentiful, they formed a little less than one tenth of the catch. In the 1930s, they again became generally more plentiful and in most rivers they are not less numerous now. It may be therefore that owing to fortuitous circumstances of water, weather, etc. Angling for grilse during the main part of their season in July and August is not more successful in the South Esk than it is elsewhere on the east coast of Scotland.
(Note: Judging by the Government’s statistics there isn’t much doubt that most grilse were killed by the nets – often well over 90% of all grilse in the District. TA 16/1/2012)
45. The South Esk during this century has evidently undergone the same change as other rivers: the dominant autumn run has ceased and has been replaced by spring and summer fish. The Inshewan records, for instance, show that in the period 1900-1910 practically all the catch was made in September and October, about half the fish being of the heavy weight typical back-end class and most of the balance grilse. The 1928-1939 records are divided into spring fish, summer fish and grilse respectively. I am told that then and now real autumn fish were and are very scarce.
46. In view of the lack of precise information, I can act only on the general statement made to me that “the stock of salmon, or at any rate the catch of salmon, has not improved in accordance with expectations over the years since sweep netting in the lower river was restricted”.
Stock of Fish
47. The general impression gathered during my inspection was that the spawning ground in the upper tributaries and in the main river from Cortachy upwards was very fully occupied. Whether the occupants had been salmon, grilse or sea trout could not be determined with accuracy. It seemed probable, however, that the majority of fish in the upper South Esk, the White Water and the lower part of the Moye burn were salmon. The total of these areas in comparison with the whole of the upper spawning ground above Inshewan is not large. In the Prosen few salmon redds seemed to exist, the majority looking like those of grilse or sea trout and perhaps mostly the latter. In the tributaries (other than the lower Moye) the great majority were probably sea trout.
48. In the main river below Cortachy observation was not by any means complete, but certainly at one reputable ford, and Superintendant Macintyre thought generally, the spawning ground was not as fully occupied as in most recent years. Chiefly summer salmon would now be here, although formerly it would have been the home of the back-end fish.
49. Of the tributaries the upper Carity was said to be full of sea trout redds with some grilse redds: the part of the burn below the dyke (see para 22) held between 50 and 100 salmon redds. The lower Noran was very overcrowded and had what seemed a fair proportion of grilse redds: the upper part was reported to hold a large number of sea trout.
50. Overall, the spawning grounds of the district (see appendix) except possibly the lower river, seem to be fully occupied: it would also seem that the fry produced will be quite sufficient to take advantage of all the available food supply for young fish. This latter factor (together with sufficient spawning ground) forms the key to the possible production of fish in any district.
Discussion
51. If for the allegation “the stock of salmon has not improved” be substituted the stock of fish has not improved” the answer would be found in para. 47 above. If the stock in the lower main river in 1957 were slightly smaller than usual, then generally the district as a whole in most years is now fully stocked. Whether that stock be chiefly salmon, grilse or sea trout is, I think, not in doubt. Salmon are very much in the minority. Grilse are perhaps relatively poorly represented, even if a number of redds in the Prosen, for instance, be credited to them: they are certainly very poorly represented in anglers’ catches. Sea trout are undoubtedly very much in the majority: they have increased very materially in numbers and apparently are still increasing. Net catches, rod catches and the type of the greater part of the spawning ground all support this fact.
(Note: This paragraph 51 poses a fascinating question about the relationship of salmon and sea trout stocks in the South Esk; ‘Is it possible that there has been a shift in emphasis away from sea trout to a recruitment of more salmon? If this is the case, could the change be attributed, among other factors, to the change from a predominantly spring regime to an autumn dominated one?’ TA 16/1/2012)
52. Although salmon form a minority of the population it would seems that the number caught by rod and line, particularly above Kinnaird dyke, may not be a true index of the total number. In two years, presumably when river conditions have been unusually favourable, materially more fish were caught above rather than below the dyke. In other years, when conditions have not been so favourable the catch below Kinnaird dyke cannot be assumed to have reduced the stock in the upper waters to a level commensurate with the rod catches made there.
(Note: Menzies writes, “may not be an index of the total number”. Indeed, I think this may still be the case. I can think of no better example to support this view than the large number of salmon seen above Brechin in March, April and May 20121, and the relatively modest catch returns. TA 16/1/2012)
53. The reason for the poor representation of salmon, especially spring fish, in the total stock, is in my opinion, not hard to find. It is the almost complete lack of what is normally regarded as typical first-class salmon spawning ground in the upper reaches. Although the salmon spawning ground of indifferent quality which exists there is well occupied, its limitations in both extent and quality form a most important factor. Nearly all spring salmon proceed to the head waters to spawn and the spawning ground in the middle and lower reaches of the river is of little service to them. The small extent of upper spawning ground controls therefore the numbers of the most desirable class of salmon. The South Esk, unlike the North Esk, has never been noted for very early clean salmon which enter the river in December and January. Similarly the Aberdeen Dee has the very early run although the main run does not commence to enter the Spey until about two months later.
54. The main part of the other spawning ground of a type useful for salmon is chiefly in the main river from Craigeassie dyke downwards, and in a part of the river which normally is occupied by summer and autumn fish. Even here most of the fords are not of outstanding quality.
(Note: As I said above, I think the importance of the main stem for spawning and juvenile habitat below Cortachy has been under-rated over the years. With the change from the dominance of spring salmon to autumn salmon it stands to reason that the middle and lower reaches of the river have become more ultilised by spawners, whereas the preference of spring salmon is to use the upper catchment. To be fair to Menzies, he was describing a different period in the cycle of salmon populations in the South Esk. TA 16/1/2012)
55. Why grilse are, and always have been, so moderate in numbers is by no means clear. Practically the whole of the Prosen, for instance, seems to be eminently suitable for them, as well as many of the other tributaries. Salmon, grilse and sea trout have very exact homing instincts, and return to the part of the river, the tributary or, it may be, to the actual spawning ground in which they were hatched. Grilse and sea trout often spawn in the same type of gravel. Grilse frequently also display a reluctance to go more than a certain distance up a river; hardly any grilse go, for instance, more than 20 miles up the Aberdeen Dee, although their passageway beyond that point is not impeded.
56. The Prosen would appear to be very well adapted for grilse. It is, however, more than 20 miles from the sea and it may be that the heavy sea trout population provides severe competition for the food for the young fish. In other tributaries, except perhaps the lower Noran competition from sea trout may be even more severe. The main river presents little spawning ground suitable for grilse and sea trout parr coming out of the tributaries ma make heavy inroads on the food supply.
57. The reason for the abundance of sea trout is also easy to find. It is the extent of the spawning ground suitable for this species in all the tributaries. In other than the main river they have nurseries and to spare everywhere.
58. Given dominance by reason of the topographical features, the habits of the sea trout parr are likely to increase that dominance. They descend from the smaller tributaries to the main tributary at the end of their first summer and, it may be, to the main river a year before the smolt migration. They are cannibals and despise neither ova nor fry. While salmon migrate as smolts almost exclusively at two years of age, about one third of the sea trout are a year older before they do so. During this third year, they necessarily become even more strenuous predators and competitors.
(Note: This I feel is Menzies at his best, taking an ecological view of the salmonids stocks of the South Esk. I find it hard to disagree with his assertion that the S3 sea trout parr (i.e. they become smolts in year 3 of their lives) are effective
predators of juvenile salmon ova & fry. If, as seems to be the case, there are in 2012 less sea trout parr in the river, this could be another reason for the improving salmon runs. TA 16/1/2012)
59. Therefore once conditions enable sea trout to assume and ascendancy, they are likely to maintain that ascendancy unless conditions for their existence in the sea become very unfavourable owing to causes of which we are as yet unaware.
60. My conclusion is that paucity of suitable spawning ground has created and maintained a relatively poor stock of salmon, and that sea trout have always found spawning facilities to be more plentiful and more agreeable than have grilse. With this background, salmon, even with a minimum of loss from nets and rods, have not been able to do more than maintain their numbers and grilse have failed to make headway against their sea trout competitors.
(Note: As I have said above, times have changed and perhaps with them, and I include climate change, the conditions in the South Esk ecosystem for sea trout relative to salmon that Menzies describes. His description gives us valuable clues for assessing the river as it is today. TA 16/1/2012)
61. This result seems to be in striking contrast to the position in the North Esk where, despite dykes and two severe natural obstructions as well as intensive fresh water netting, the salmon stock is reported to have at least maintained its numbers: the dykes and obstacles were improved in 1949 by passes or blasting. In general geographic features the South Esk is not unlike the North Esk. The basic South Esk data are given in para. 3 above. The corresponding figures for the North Esk are 41 miles long, rises at 2,700 feet and total catchment area 297 square miles. A comparison of the physical conditions affecting salmon in the two districts might be rewarding.
(Note: I understand why Menzies suggests a comparison with the North Esk, but I disagree that this is now the best way forward for the South Esk. While the North Esk as the Scottish ‘marker’ river provides useful data on trends, we should recognise that the topographical, chemical and biological makeup of the South Esk is unique and requires a broader basis for comparison than only a river that is close by. Any future assessment of the South Esk should in my view be on the river’s own merits in the context of prevailing regional, national and bioregional trends. TA 16/1/2012)
62. Poor statistics and a very small amount of verbal evidence suggest that the catch of fish in the river above Kinnaird dyke is no commensurate with the stock. The number of dykes which exist may well be an important factor contributing to this result.
(Note: this is an interesting observation, which tallies with my own view of the problem of trying to assess stocks purely on the basis of rod catches. The comment about the effect of the dams is also relevant because in the last decade we have seen their influence on migrating fish largely removed. TA on 16/1/2012)
63. The South Esk has a wide channel. The dykes are therefore necessarily of some length and in floods the fish will generally be well scattered across the channel. When set diagonally as, for example at Kinnaird and Craigeassie, the length of the dyes is formidable. At dykes of this old-fashioned type, set in a straight line and with a level sill (except Kinnaird), a direct lead for any ascending fish to the fish pass does not exist. Consequently, very many of the fish may spend a great deal of time trying to find the fish pass up which, in the end, they may be able to ascend easily. If the spate which induces the fish to move be short-lived, or if they start at the wrong end of the dyke, or if, in the earlier spring months the water temperature is, or falls, below the critical 42-45 degrees F., the fish may well drop back to wait for the next spate together with a rise in water temperature. (In any event practically all the early fish will remain below the Kinnaird dyke, even with the improved pass, until the water temperature reaches the critical level). If the fish be held up to a greater or lesser extent at each dyke in turn, and if some of them at each dyke drop back at each spate, at least many of them must be stale and very reluctant takers of any lure before they reach the upper angling waters. This hold-up and frustration, repeated it may be several times, may well lead to an unusually small proportion of the total stock falling to rod and line.
(Note: And here of course is the rub, because Menzies’ argument is that anglers fishing upper river beats will never have the opportunity of casting their flies at fresh salmon. In the context of the river as it is in 2012 this argument becomes less valid because most of the dams and other obstructions to migration have gone, some more recently than others. The river’s catch returns already show a marked decline in Kinnaird’s catches, but perhaps not the improvement on might expect further upriver on beats such as Cortachy, Finavon and Inshewan. My view is that we are seeing here the measurable effects of the huge decline in marine survival. The cake has got a lot smaller – perhaps as much as 50% smaller – which means that there simply aren’t enough fish to give the upper river beats the boost they have all been anticipating. TA on 16/1/2012)
Recommendations
64. If my conclusions be correct, the main line of approach to increase the stock of salmon and grilse must be to try to increase the spawning facilities: the alternative of the destruction of the sea trout as being both predators and competitors is not practicable.
(Note: Exterminating South Esk sea trout? Thank goodness he didn’t go down that road! TA on 16/1/2012)
65. The only considerable stretch of water in the District unused for spawning is the flat reach in the main river, 9 miles long, above Cortachy. In this reach a number of constrictions cause a slight run of water at various points. The planting of beds of gravel of suitable size on an experimental basis, with a view to establishing fords at two or three of these constrictions would be worthwhile, provided agreement can be reached with the landowners concerned and any undue increase in flooding be avoided.
(Note: I feel that this is as bit of a shot in the dark rather untypical of Menzies’ otherwise logical and measured approach. The idea of making ‘spawning fords’ as one sees on rivers like the Gruinard in Wester-Ross is original, but I wonder how cost effective and whether this should be so high on his priority list for restoration? TA on 16/1/2012)
66. Similarly experimental planting of gravel to improve the spawning facilities in the lower Moye (and in the upper Moye if necessary) could be tried.
(Note: Less spate energy in the Moye Burn would probably allow the gravel fords to stabilise, causing less disruption, and logistically an easier operation to carry out than on the main river. It would be interesting to have seen Menzies’ recommended gravel stone diameter for salmon spawning. TA on 16/1/2012)
67. The creation of areas of gravel in the bed of the Lower Rottal might help to hasten the return of spawning salmon to that tributary.
(Note: His emphasis on spawning is not the issue in the Rottal Burn (downstream of the road) because fish undoubtedly do spawn there in the clean gravel washed by the fast, straight current. The issue is the lack of juvenile habitat, which is why the plan to restore the Rottal Burn is so important. TA. Jan 2012)
68. Likewise the creation of areas of gravel of as size rather too large for sea trout but suitable for grilse might help to increase the number of grilse in the Prosen and the Noran.
(Note: I wonder what size of gravel unit he had in mind? 1.5” to 2”? TA. 16/1/2012)
69. These experimental plantings of gravel should be made early in the year, so that the gravel settles down and the effect of spates can be seen before the first spawning season.
70. In the upper main river flat reach and the Rottal the new gravel should be “seeded” with ova in plastic boxes. Since the numbers required are small, the ova taken from fish spawning in other parts of the District could be planted “green” and the use of a hatchery avoided.
(Note: Isn’t it interesting that in 1957 Bill Menzies was making an effort to avoid using a hatchery? But is his ‘green seeding’ really the best way forward? Why didn’t he just suggest leaving the new gravel ‘fords’ to attract wild fish returning to those locations naturally? I really cannot see the advantage this “seeding” provides. TA on 16/1/2012)
71. The steps required to achieve better and more rapid distribution of ascending clean fish throughout the river is clear, i.e. the destruction or breaching of the dykes. A breach in a dyke forms the best, and indeed the only completely satisfactory fish pass. At least some of the dykes no longer serve any useful purpose: a breach in each of them would greatly help the salmon fisheries and might relieve to some extent the flooding of land.
(Note: Here Menzies comes up with the solution to the main problems of the South Esk. It took more than 40 years for his vision of free passage for migratory fish to be realised, but it can be said that at last we have that situation! His idea that removal of the dams would alleviate flooding, given the locations of those dams, really doesn’t make sense, as any modern hydrologist could explain. TA on 16/1/2012)
72. Improved facilities for the ascent of fish at obstructions on a few of the tributaries should be provided: work at the Falls of Moye has already been started.
(Note: Work on the access to the White Burn following damage done during construction of the new road bridge at Shielhill was completed by Colin Gibb and Hugh Cameron (using gelignite!) in the 1960s with the result that fish now have easy access to this important spawning burn. TA 16/1/2012)
73. Although so far the river has avoided a major disaster from Brechin sewage effluent, the potential danger is very real. Complete treatment (and not merely sedimentation) of the sewage and industrial wastes is urgently necessary.
74. Mergansers and Cormorants may exact some toll and will not be selective between salmon and sea trout parr and smolts. Their numbers should be kept to a minimum.
(Note: it is very unlikely that licences will ever be issued to kill the numbers of cormorants and saw-billed ducks seen as necessary by Menzies. TA on 16/1/2012)
75. Steps should be taken to ascertain if the enormous breeding flock of black headed gulls in Kinnordy loch takes any material toll of the fry, parr and smolts in the main river and perhaps especially in its upper tributaries.
76. A complete census of, and watch on, all sheep dipping tanks should be maintained.
(sgd) W.J.M. Menzies
January 1958