SOME PRELIMINARY OBSERVATIONS ON THE MIGRATIONS OF SALMON (SALMO SALAR) ON THE COASTS OF .

BY

W. J. M. MENZIES, F. R. S. E. Inspector of Salmon Fisheries of Scotland. — 18 —

IXED nets for the capture of salmon were from low water mark. This practice of “out- first used on the coast of Scotland just overrigging” the nets is extending and this year it was successfully employed at the experimental marking F one hundred and ten years ago (ca. 1827) station on the west coast where only single nets and from the success which they immediately are still usually employed. obtained, and which has been continued, it is evident that the salmon in the course of their sea When lines of nets are fished in this fashion life come close inshore. At first no doubt it was and two lines of six or more nets each are fished not realised whether the fish were feeding or were with equal success within two hundred yards or so on migration when captured. In later years it has of each other, it is clear that the migration of the become clear that the fish have ceased feeding salmon along the coast cannot be a simple progress before they reach the coast and that they may be in one direction and in a comparatively straight line. considered to be then on their way from the feeding The Figures 1 and 2 are charts of St. Cyrus and to the spawning grounds. For long it was thought Lunan Bays showing the spacing of the nets and the that the fixed nets were only of importance to number used at each position. These illustrate how the rivers near which they were situated and that impossible it would be for salmon to enter the the fish taken by them were to be regarded as part bays only Irom either end and to attempt to swim of the stock of the neigbourhood. It was clear, along the shore or for them to do so from any however, that in certain cases this opinion had to particular point within each bay. For all the nets be interpreted somewhat widely for nets set at con­ shown in these figures to be successful it is clearly siderable distances from the mouths of rivers of necessary for the salmon to approach the bays from a n y importance were often quite successful. any direction and towards any part of the bay. Little can be learned of the precise movements Similarly were salmon to follow this alleged habit of salmon from commercial fishing beyond the fact then those released from a marking station would that, on a comparatively unindented coast, such as all be captured by a particular set of nets in either the east or north coasts of Scotland, salmon are to one direction or the other and were any consider­ be found at relatively considerable distances able journey started in the direction of a thickly (twenty or more miles) from the mouths of rivers netted area the attempt would soon be terminated of importance. It has been assumed that the fish by the capture of the fish. swim along the coast close to the shore for con­ Consideration of all the facts shows that when siderable distances and it has been stated that, at making a definite migration the salmon may do various parts of the coast, the line of migration is the journey in a more or less direct course but at predominantly in one direction. On an open coast some distance, probably greater than half a mile, where bag nets are set singly and at some distance from the coast. On the other hand when near (quarter to half a mile) from each other it is not its destination, or when waiting for water to tempt impossible that the fish should swim more or it to ascend a river, it moves in a straight line less parallel to, and within a few hundred yards along the shore for only a very short distance and of, the shore. But further examination in more these little journeys close to the edge of the water intensively netted areas shows that this suggested are interspersed between quite definite on and off movement cannot occur. In some districts, e.g., St. shore movements that may extend to a distance of Cyrus Bay, Lunan Bay (both near Montrose), and probably several miles from high water mark. Largo Bay in the of Forth bag nets have As justification for the assumption of a move­ been fished for very many years the one beyond ment predominantly in one direction or the other the other until sometimes six or eight are in a along the coast, fishermen state that they see the fish straight line stretching for roughly half a mile IVeUgretn rus

•Œ otel Oondt (Mon JVess

J io a d m d e ' *School

BU 372 0

C nU m

afKirkÿ K x rk ev it C ottage ^

ih^ÿStaivm. WhtUcraigIDuuttäJ Q

1 Mile Pathhead/

' N ä h e r W arburton

• ï ‘f O' >i .11 !• *\1

o

ORKNEY

Duncansby Head

J&arvas HELMSDALE

/H elmsdalC føirÆ RSTfc BROftfi

HELHSDALE

H e lm s d a le /) Naver / ness HELMSDflt-E

Ielhsdau DEVEZ?!)* ^Heimsdble iSpey ^*? DEDERON

DEHERON /Iberdeen HartSDAii

Deveron

Deveron

Montrose

'N.y'SPEY Tw iS1\RUNC Of rom

Edinburgh

Fig. 3

— 19 — (111, 2) so moving (by watching the progress of a shoal in the inner Firth between the Deveron and which the fish are jumping) or that the fish are Wick, since these fish are within close range of believed to enter the nets from one side more than their own river. It is hard to attach the correct from the other (a bag net has a wall of netting at significance to the other fish which appeared in right angles to the shore which leads the fish into diametrically opposed directions. The two taken a trap and is normally arranged so that fish may on the north coast, where another fish from the enter the trap from either side although very rarely Brora which adjoins the Helmsdale was also caught, it is made so that fish can enter from only one suggest a migration in from the north while the side). two, caught respectively near Peterhead and Salmon certainly do have two quite definite but Aberdeen, to the south equally indicate a move in temporary movements. The first is that they come from the south. As I shall explain later it is to the lee shore in a most marked manner; with possible that these apparently divergent results are a wind blowing on to the shore bag nets will fish the true indication of divided routes of migration. well but with a wind blowing off the shore the In distinction from the Helmsdale results we catches are invariably poor after the first day of have a rather striking uniformity of recaptures to the change of wind. If then the prevailing wind the south of the place of marking in the case of (in Scotland normally south-westerly) blow along salmon marked in Spey and Deveron. These fish any particular piece of coast salmon close inshore have been caught between Peterhead and Aberdeen will normally travel with the wind and can be seen but not at all on the north coast. A similar move so jumping and moving. Salmon when close to is also shown by a single fish from the Naver on the shore also travel temporarily with the tidal the north coast which was recaught near stream even if that stream be an eddy and not the Ness in the inner . On the north coast true tidal stream. In certain situations, close to a two fish from the west side of Lewis (Grimersta promontory or in a bay, the true tidal stream may and Barvas respectively) were retaken in or near be succeeded by an eddy stream flowing in the Bay and another from the West Ross Carron same direction; here salmon will move mainly at Melvich. On the West coast there are only two in the one direction, which is that of the longest recaptures of note but when compared with the flowing stream, combined of true tide and eddy. results of marking in the sea they are of particular Fishermen working in such situations will say that interest. Two salmon marked in the Awe which the fish run in a certain direction. But it is a enters the sea near Oban were captured on the purely local effect and has no relation to the shores of the Minch and were thus returning to main run of fish along a larger section of the coast. their river from a northerly direction. The alleged general movement of salmon in a It became clear that kelt marking was not going certain direction along certain parts of the coast to give any very direct answer when carried out has on several occasions been proved by our on the scale that was then possible and a more marking work to be incorrect. direct attack on the problem of the migrations of The marking of salmon as means of providing the salmon along the coast of Scotland was planned. information regarding the life history of the fish In the normal commercial method of capture in was started in Scotland in 1896 and between then the sea by means of fixed traps (bag nets or fly and 1912 some few indications were obtained of nets) into which the fish swim and in which they the possible movement of salmon along the coasts remain swimming without being caught in the at considerable distances from their river of origin. meshes of the net, salmon are retained without any The marking was confined to kelts and some of the harm until they are removed for the market. Such longer journeys indicated by these marked fish and engines are, therefore, ideal for experimental pur­ other kelts marked subsequent to 1912 may be poses although, owing to the fact that almost all quoted. the most profitable sites are occupied with com­ On the map in Figure 3 I have indicated the mercial fisheries, it is difficult to put the nets for position of recaptured fish by placing at the experimental purposes in places where an adequate recapture station the name of the river in which number of fish can be caught. they were marked. It is necessary to remember Experimental netting took place from 1913— that they were marked as kelts and were retaken 1915, 1920— 1921 and 1936— 1937 all inclusive when clean. When finally caught they may be and the exact sites of the various stations are shown regarded as on their way back to their original on Figure 4. rivers. The names of certain rivers will be found In 1913 a start was made in catching to predominate but no significance is to be clean salmon in bag nets, marking them and attached to this: it simply indicates the districts releasing them again into the sea. The site chosen where most marking was done. If we take first was at the head of the Moray Firth (see Figure 4) the river represented most numerously -— the where salmon were known to be reasonably plen­ Helmsdale — we find fish retaken all the way tiful and in the neighbourhood of which are large from the north coast down to Aberdeen. No numbers of bag nets. This site was of interest significance need be attached to the recaptures in because it was quite close to the bottle neck of the 2’ — 20 —

T hu!

W i c k *

L e w i s

,K Y £

narrows leading to the Inverness Firth: inside the was taken in the Fleet the mouth of which is close narrows fixed nets are not set. These nets, there­ to the Kyle of . fore, were the last fixed nets which the fish would The recapture in the sea nets should perhaps encounter on their way up to the Ness and Beauly be of greater interest, but they are a little unin­ rivers, the mouths of which are situated near the formative, since, viewed as a whole, they merely top of the firth. The experiment was continued represent the fish as scattering along the shores of during the summer of 1913, for the greater part the Firth between Rosemarkie and Tarbet Ness to of that winter and in the summer of 1914, 1019 the north, and between Fort George and Port fish were marked and 28 per cent, of these were Gordon on the east. It is easier to visualise the recaptured. The results fall quite clearly into two fish in this rather restricted area as travelling on divisions, being those which were obtained in the a roughly circular course round the narrow part summer months of May to August inclusive and of the firth, while waiting for water to reach their those for the winter months October to January, own river,.than to imagine them making a definite also inclusive. course and journey for which either one shore or In such a situation one would expect a goodly the other might form the guiding line. I do not proportion of the fish to be on their way to the consider that, under the circumstances, the exact Ness and Beauly rivers. To a limited extent this number of fish caught on each side of the firth proved to be the case (see Figure 5). But in forms any sort of reliable index of the movement but addition to these there were others, and they were in the twenty-two miles from Rosemarkie to Tarbet far more numerous, which, after approaching the Ness seventy four fish were taken, and in the same bottle neck, again turned out to sea, and were distance on the southern shore (from Fort George retaken either in some of the numerous nets along to the neighbourhood of Burghead) exactly the the shores of the Moray Firth or in the rivers which same number were caught. Outside this radius of flow into it. A number were found in the sweep twenty-two miles we find only sixteen fish taken nets of the Kyle of Sutherland at , in coastal nets, and of these, twelve were grouped and others in Spey, Findhom, Nairn and Conon on one or other side of Spey mouth. Forty-five (whither a considerable number travelled). One fish were also taken in estuarial or fresh waters Golspie

6 tt. ♦. y) »(jéO\V !!»♦.r it? ' «T Wj • (7^»(23ÏV*ï „OCH F'»™«Y

J(8)

Peterhead

Inverness

^ r-^ 7

berdeèn

Fig. 5

DUNN ET )WI; EljAY

LY HS

DUNBEATH O.

ERRIEDALE

HELMSDALE

TS

BRORA

A Y

BONAR'BRf‘DiQ TAR BAT NEJ

IOCKFIELD

’ORTGORD ANFF TINDHORi E LCI

DI.NGWA FORRES NAIRN

I NV ERNES’

Fig. 6

— 21 — ( 111, 2) beyond the twenty-two miles limit, and of these From these inner waters few fish make long thirty were in the Kyle of Sutherland, and eleven journeys and those that do so travel south. in the Spey, districts. The next marking station, in 1915, was about Apart from these localised movements we have 35 miles to the north of the first and towards records of five other fish which travelled beyond Duneansby Head. (1773 fish marked, 23 per cent, ■— in four cases far beyond — the local limits. recaptured). This station may also be regarded as One was taken at Gardenstown on the east of Banff, well within the waters of the Moray Firth and the and some seventy miles away from our nets; the migrations of the majority of the fish were found four others (all grilse) being the balance of the to be similar to those at the first station. The forty-five fish referred to above, continued on notable change was that the area of movement was round Buchan Ness, two for 160 miles to the North enlarged and instead of extending from Tarbat Esk, while the two others ascended the Firth of Ness across the firth to Burghead, it was enclosed Forth, and were taken near Alloa, 250 miles from by a line drawn from Lybster (South of Wick) to the place of marking. the mouth of the Spey. Viewing the experiment as a whole, probably the A much larger number were taken in the most noticeable point which emerges is the number Kintradwell than in the Black Isle nets, and on of fish — thirty — which have moved north to the viewing the map, Figure 6, we see a correspond­ Kyle of Sutherland and to the rivers which flow ingly larger number of recaptures set out, the into it. This is a greater number than were taken majority of them being again grouped on the coast in any other estuary and river, although the place within thirty miles of the place of marking. Before of marking was situated in the outer estuarial we can rightly consider the true significance of waters, as it were, of the Ness and Beauly, and not these migratory movements, we must remember that far from the direct line of approach to the Conon. the summer of 1915 was very dry in the north-east In the Conon twenty-three marked salmon were of Scotland, and that there was no spate from the found, eleven were taken in the Beauly, and time the grilse, which formed the majority of twenty-two in the Ness. The majority of the Ness marked fish, began to run until the end of July; fish were winter fish, which were marked between further, that practically the whole of the recaptures October and January. were made prior to, or immediately at, the com­ The conclusion we can draw is that while a mencement of the spate. When the flood came, the certain number of the summer fish were going salmon, both adolescent and adult, deserted the sea north on their way to the Kyle of Sutherland, the for the river. great majority confined their movements to an area Between the Black Isle and the Sutherland in the firth within twenty-five miles of Rosemarkie, coasts there is also a great difference. Along the and were either directly on their way to the rivers Ross-shire shore and the southern side of the Moray situated to the west and north of Spey and to the Firth practically every available position is occu­ south and east of Conon at the head of the Cromarty pied by a fly net or by a bag net, and very often Firth, or were merely waiting for a favourable four or five of the latter are outrigged, the one opportunity to ascend them. We have no evidence, beyond the other, into the sea. Along the Suther­ other than the movement to the Kyle of Sutherland, land coast there are neither fly nor bag nets from of any definite lines of migration, nor were any the entrance to the Dornoch Firth to the county fish, marked when grilse, recaptured as maiden march at the Ord of . Debouching from spring or summer fish in the following year. that coast line are two rivers of major and one The winter fish displayed quite other charac­ of minor, importance from a salmon fishery point teristics and since commercial nets were not then of view -— the two former being Helmsdale and in use (the close season extends from approximate­ Brora and the last the Fleet. Farther north, beyond ly the end of August to the middle of February) the Ord of Caithness, bag nets are in plenty, and none of them were expected to be caught in the there also are to be found the little rivers of Ber- sea. The possible rivers of capture were also riedale and Dunbeath and the Wick river, although limited since comparatively few Scottish rivers in the latter salmon are almost extinct. hold clean winter fish. As events subsequently If we again look at the map we now have a proved, most of the marked fish continued up what better understanding of the significance of the appears to be the natural channel to the Ness with recaptures. The great majority were made in the a much smaller proportion to the Spey. first fixed nets which the fish encountered while The results of these marking experiments of cruising along the coast in a northerly direction, 1913—1914 show that the fish found at the inner and a considerable number were also taken rather narrows of the Moray Firth are not in the majority farther up the coast at Dunbeath and Lybster. of cases proceeding to one of the rivers at the head Beyond Lybster the numbers caught are quite in­ of the firth, but may be natives of any of the significant; the Wick bag-net station had only one Moray Firth rivers and, while waiting to ascend marked fish. To the north of Wick, at Freswick into fresh water, have a comparatively limited there were only two, and at Keiss six. In the nets cruising range within the inner part of the firth. worked at the mouth of the Brora river a number — 22 —

were captured, and a few farther up the river. playground along the coast. We have to extend our None were found in the Fleet, but quite a number radius to a distance of thirty miles from the place were taken on the rod in the Helmsdale. In our of marking to cover the great majority of the own nets at Kintradwell twenty-six were found for recaptures. Beyond this the only group of im­ a second time and this, in conjunction with the portance other than those taken north of Lybster, quantities at the first fixed nets to the north seems is that of thirty-five fish taken in the Spey district, to me significant, if we remember that the year about forty miles from Kintradwell. was dry and the rivers were low. At the first As in 1913 and 1914, we find marked fish glance a very marked northern migration would turning up along the Cromarty—Tarbet Ness shore, appear to be shown, but from the lack of recaptures in the fixed nets round Naim an Findhorn, and a in 1916 it is evident that all our fish were on the few at Port Gordon, which would seem to neces­ way to fresh water in 1915, and, there, must have sitate the extension of the previous expressed view been on their way to a river when caught and of the possibilities of a circular movement round marked. If we are to take this northern migration part of the Moray Firth. A wider area than was as a fact, we shall have to imagine the destination suggested by the Black Isle results alone now which the fish were seeking, if it be that the fish seems to be involved. Salmon in the comparatively intended to ignore the Helmsdale, it hardly seems confined area may move about with some freedom, possible that they would do so to group themselves and possibly may follow the whirl-pool-like set of round the mouths of the quite unimportant streams the tide, the drift of which, after the main south- at Berriedale and Dunbeath — streams, moreover, going current strikes the shore and divides west which are patently occupied only by a comparative­ of Lossiemouth, is west, along the southern shore, ly small number of salmon and grilse, and not by and then north-east past Tarbet Ness. Naturally the considerable quantity which would appear to one cannot be certain of the exact track of the fish, be indicated by the recaptures in the fixed nets. but, since they are known to travel with the set of Moreover thirty marked fish were caught in the tide along the shore, the circular movement the Helmsdale and not a single fish in the rivers would seem more probable than the point-to-point further to the north. If the important river progress, which would be indicated by merely Helmsdale is to be definitely passed, one would joining up the places of marking and recapture expect the larger part of such a considerable with a series of straight lines. number of fish to proceed farther along the shore, The river recaptures from this series of mark­ round Duncansby Head, and to the larger rivers of ings are rather interesting, and show that while a the north coast. The recaptures of marked fish considerable number of the Findhorn and Spey show that this is not the case, and the explanation fish have approached their destinations by the would rather seem to be that we are here dealing Sutherland coast, very few of those going to the with the bulk of the summer stock of salmon of Ness, Beauly, and Conon have done so. If we the Brora and Helmsdale which are cruising along compare the two maps of the different marking the coast and biding their time, as it were, until experiments, we see clearly the change, and how the rivers should be of a height sufficient to enable the fish coming into the bottle neck of the firth them to ascend from the sea. In this time of wait­ apparently do so from some direction other than ing they have a playground twenty-five miles long, the north. The fish destined for the rivers clear of all nets except those of our experimental inside the bottle neck — i.e., Ness and Beauly — station, and here they doubtless disported them­ do not extend their wanderings to the Sutherland selves with freedom; but when their joumeyings coast, even in a dry year, when waiting for suf­ took them within the much-netted area of south­ ficient water to run the river, for otherwise we east Caithness many were captured, and were not would have found more going to those districts released, as was the case at Kintradwell. Of an from Kintradwell. Another point of interest is that undoubted northern migration, I venture to think of a far greater number of fish marked at Kintrad­ we can only count those nine fish which I have well, fewer have gone to the contiguous Kyle of already enumerated at Wick, Keiss and Freshwick, Sutherland than went there from the more distant and one other which proceeded through the Pent- Black Isle nets. land Firth, and was caught on the east side of As well as the more important recaptures Dunnet Head. indicative of the general movement of the majority The other recaptures effected in fixed nets on of the salmon which we have considered, there are the coast are distinctly to the south of the place of a few fish which journey considerable distances. marking, and are grouped very much in the same For instance, a salmon went to Lochinver on the nets as the Black Isle marked fish were grouped, west coast — a sea passage 130 miles from except for a somewhat distinct paucity of captures Kintradwell; another travelled 240 miles to the between Rosemarkie and Cromarty. We also find Coquet in Northumberland; and other individuals on this occasion rather more on the west side of to Aberdeen (112 miles), Montrose (150 miles), Tarbet Ness, which perhaps conform to the the Tay (200 miles) and the Coquet (240 miles). suggestion I have made about the movements in the From this marking experiment, signs of any 23 — (III, 2)

P e n t l a n o Firth

D u n n e t H*

Th N e ts

Wick

definite and clear line of migration are difficult recaptures were made within a very few (fifteen) to find. A movement from the nets to the Helms­ miles, all being to the west of the bay although dale a distance of some eight miles, can scarcely this is not completely significant since only one be regarded as a definite northerly migration in bag net station of small importance exists in the view of the distances which salmon easily travel in hard running tides to the east of the bay. The nets the sea in a short period of time; nor, for the were set quite close to the mounth of the river reasons I have already stated, do I regard the Thurso and before the start of the experiment it recaptures in the south-east of Caithness as indices was fairly evident that a considerable number of of direction. A certain number of fish have gone fish destined for the Thurso river would be caught. to the rivers south of the place of marking — e.g., This proved to be the case. But the configuration Findhorn and Spey. On the whole, I think it of the land at Holborn Head to the west, and probably better to be satisfied with the provisional Dunnet Head to the east, of the bay is such as conclusion which we have already reached -—• would naturally lead salmon into the bay: it namely, that in a dry year there is probably a seemed possible, therefore, that fish striking in to circular movement of salmon round the firth in the coast in this neighbourhood might swim round general, with a more restricted migration of fish the bay before proceeding further on their journey. belonging to the east Sutherland rivers along the The rainfall was so small that there was no coast of that county, and of the southern part of flood in the rivers between mid-June and mid- Caithness. September and during this time no salmon entered In 1920 a marking station, operated in Thurso fresh water. The marked fish consequently had Bay from May to September (478 fish marked, ample opportunity of scattering as far as they 14 per cent, recaptured), showed a much more might desire but of the 62 recaptures 38 were taken restricted area of movement (Figure 7) and most in Thurso Bay and river. Of the remainder, 17 were taken in the first nets worked in the sea to the north coast 45 miles west of Thurso at Talmine the west, and within eleven miles, of Thurso Bay on the (100 fish marked, 9 re­ and two were taken in north coast rivers only one captured), dealt with very few fish of which a of which — the Hope — is a significant distance very small proportion were recaptured. But the (50 miles) from Thurso. Of the remaining three interest of the results obtained was out of all fish two went round Duncansby Head to Wick and proportion to the numbers. Of one hundred fish the other travelled 115 miles in the opposite marked and nine recaptured (Figure 8) only three direction round Cape Wrath to Gruinard Bay. were found within 30 miles of the place of mark­ Here in this Thurso Bay marking in spite of ing: two of these were taken in the Hope district, ideal conditions for the distribution of the fish we which is the first river to the westward round find an actual major distribution within less than Whiten Head, and some fifteen miles from Talmine; half the distance covered by the Moray Firth fish. and the other was found in the Halladale, some The evidence shows very clearly a local stock of twenty-five miles east of the Kyle of Tongue. Of salmon which have finished their main migration the other six, four had gone westward to Cape from their feeding grounds and are waiting for an Wrath, and then some considerable distance to the opportunity to ascend the one of the three neigh­ south. One of the four completed at least sixty- bouring rivers — Thurso, Forss and Halladale-— to four miles in all to Clachtoll, a bag-net station a which they belong. While so waiting they cruise few miles to the north of Lochinver. Another about in shoals along this very short stretch of travelled eighty-six miles to Gruinard Bay, and the coast frequenting temporarily first one and then third was found at Badentarbert, on the northern another comparatively limited area according to side of the entrance to Loch Broom, eighty miles the prevailing wind and the particular tidal stream from our nets. The fourth fish, which had moved in which they happen to be. The wider migrations west, avoided all coast nets, and was not found are very restricted in number hut, in the light of until caught on the rod, when a kelt, in Loch Clair evidence obtained in later years, are of particular at the head of the Ewe district, in April 1922, interest. Two went east and then south: two went eleven months after it was marked. This was a west and one of these continued southwards down greater traveller than any of the others, as it the west coast. covered at least 120 miles. Of the eastward In the summer of 1921 a station, established on journeys one to the Halladale has already been Sognefjord, Norway 57

— 25 — (1 1 1 , 2) mentioned. Two other salmon swam past the north­ indications are, however, that the incidence of east point of the mainland of Scotland, and con­ recapture would not have been high. tinued south. One, after travelling 140 miles, was But in addition to these purely local movements retaken at Cromarty, hut the other was not found of the local stock, for which there is ample until it had reached the Avon, a tributary of the precedent in the earlier experiments, we found from Spey, some twenty-seven miles from the mouth of Loch Inchard a very extensive move on the part the river. If this latter fish moved parallel with of many of the recaptured fish the possibility of the coast line for the major part of the way, the which had been indicated at the Kyle of Tongue. journey between the time of marking and the time In this year the long range migrations embraced of recapture was one of some 240 miles. not merely a few fish but included the majority of Subsequent to 1921 a long gap existed before those which were again reported. Of the 34 fish it was possible to resume this work in 1936 on the recaptured in 1913 79 per cent, were found within west coast at Loch Inchard ( 1255 fish marked, 25 miles of the place of marking and for 1915 12 per cent, recaptured) which is some twelve and for 1920 (Thurso Bay) the relative figures miles south of Cape Wrath and round the corner were 76 and 97 per cent, respectively. Now in as it were from the Kyle of Tongue. Here netting 1936 if we extend the first area to fifty miles on conditions were the same as at the Kyle of Tongue. either side of Loch Inchard we find that only They were different from those at Thurso Bay and fifty-one out of one hundred and forty seven fish still more different from the conditions in the were there taken and that, therefore, 65 per cent, earlier years when the work was carried out in the were recaptured outside an area which is twice as Moray Firth. Along the whole of the Moray Firth long in each direction as that used for the earlier coasts fixed nets are numerous and sweep nets are stations. In point of fact the journeys undertaken worked for the greater part of the legal season in (Figure 9) extended to the Sognefjord, Norway the lower waters of many of the rivers. Near (400 miles), and Whitby on the Yorkshire coast in Thurso fixed nets are worked to the westward but the north-east of England (410 miles). Many of are not so numerous as in the Moray Firth; sweep the nearer fish were necessarily found in rivers nets are also not worked so intensively. Near the and some of those which went for a much longer Kyle of Tongue and Loch Inchard sweep nets are distance were similarly recovered in fresh water, not used, fixed nets are absent on the north coast e.g., rivers Shin (180 miles), Conon (160 miles), to the west of Strathy Point (see Figure 4) and Spey (145 miles), Tay (290 miles), Forth (300 are not found on the west coast until Rhu Stoer miles), Tweed (300 miles). Those that were not is reached (thirty miles from Cape Wrath). From actually in fresh water were often grouped in nets this last point southwards, however, they are set close to the mouths of certain rivers, e.g., Naver moderately numerous down to, and including, the (40 miles, 6 fisTi), Halladale (52 miles, 28 fish), north-east coast of Skye, although they are absent Forrs (64 miles, 5 fish), Thurso (70 miles, 24 from the islands on the western side af the Minch. fish). Five fish taken in the bag nets of the east One consequently could not expect to find a con­ coast of Caithness occupied positions known from centration of recaptures along the coast within a our work in 1915 to be frequented during dry limited distance of the place of marking. Yet at weather by salmon from the rivers Brora and the same time the absence of nets cannot be held to Helmsdale: single fish taken in the Moray Firth encourage the capture of fish at a distance by the near the Spey and on either side of Aberdeen (200 elimination of the possibility of capture near the miles) and five caught near Montrose (230 miles) place of marking. The Thurso Bay fish, for may belong to one or other of the rivers of the instance, had ample opportunity of moving right part of the coast concerned or when finally away from that area during the long dry period captured may have been occupied in a still longer of 1920 just as the East Sutherland fish in 1915 journey. The movements and destination of the had more than adequate room and opportunity for fish on the coasts south of Buchan Ness, and making long journeys from the considerable stretch particularly that part near Montrose, require of coast (25 miles) entirely without nets to both investigation and elucidation before anything can north and south of the place of marking. The be said as to the lines of migration and origin of absence of nets in 1936 precluded recaptures along the fish caught here. Further south the fish in Tay the coast within twenty miles to the south and about and Forth and Tweed, and the last caught by a forty-five miles to the north and east of the place drift net off Whitby (410 miles) have already been of marking. Recaptures made in our own nets, in noted: like those of the Aberdeen and Montrose the first bag net station (on north side of Rhu coast this, the Whitby fish, belongs to an unknown Stoer) to the south and in the first two rivers of river. the north coast suggest that had nets been set a On the west coast the fish are less markedly certain number of fish would have been caught in grouped round the rivers but the nets are not the area, say twenty miles in extent in either so set as to bring out this particular arrangement direction, just as recaptures were made round the even if it does exist. Some are found actually in places of marking in the Moray Firth. The the nearer rivers, e.g., Cannaird (47 miles), Broom Plate I 5 V2 Ibs ; 63 cm; marked Loch Inchard 8/6/36: Recaptured Sognefjord, Norway, 29/7/36: 2-1+ (Part of adult fish scale).

(55 miles), Ewe (53 miles) and three in rivers of Scales from recaptured fish indicated that those Lewis, viz., Soval (57 miles), Grimersta (75 miles). caught in, or at the mouth of, various rivers had In the bag nets they were found on the east side the parr areas of their scales similar to the parr of Skye (80 miles, 4 fish), on the island of Soay scale area of fish known to be native of those (130 miles), Loch Nevis (117 miles) and down rivers. So distinctive is the parr scale growth that to the north of Mull (150 miles). these scales show without possibility of doubt that 27 _ (III, 2)

Plate II, a 51b. lOozs; 66% cm.; marked Loch Inchard 6/7/36: Recaptured Tweed, 23/7/36: 2-1—(— (Part of adult fish scale). the fish in question had not made a chance journey which had a parr area (Plate I) typical of that to an unparticularised destination but had made a of Norwegian salmon in general and quite unlike definite migration back to the river from which they that of Scottish rivers. The Tweed recapture on originally descended as smolts. This differentiation the other hand had scales of a very rapid growth- of the parr growth is also well shown in the scales type which is quite different from the type of of the fish which was recaught at Sognefjord and other east coast rivers. A photograph of the scales — 28 —

Plate II, b Tweed two-years-old smolt. (Part of adult fish scale). is given in Plate II a together with (Plate II b) the only one fish was recaught on that coast for every parr area of a typical Tweed salmon scale of the three that were caught on the north and east coasts. same (two years) smolt age. It would appear that many fish strike in to this This homing instinct is further borne out by part of the coast when on their way back from the scales from three salmon, sent to me by Professor feeding grounds but when still a considerable Knut Dahl, marked in Norway and recaptured distance from their own rivers, and that the fish in Scotland. One of these taken in a coast net at belonging to the nearer rivers form only a relatively Montrose was of a general east coast type and could small proportion of the total. not be allocated to any particular river: it might To test the 1936 results the experimental have been a native of the South or North Esk or station was moved only twenty miles south of Loch the Don, it certainly did not belong to Dee, Forth Inchard in 1937 and at Raffin (448 fish marked. or Tweed. The Forth parr scales are particularly 13 per cent, recaptured) just to the south of Rhu well “marked” by a small first, and a large second, Stoer, it was approximately half-way down the year’s growth; the marked fish caught in that river Minch (Figure 10). This situation, however, did reproduced exactly this type of growth (Plate III a not reveal a different run of salmon. The results b and c). In the Tweed parr growth throughout life obtained practically duplicated those of the previous is exceptionally good and this again is exemplified year, the only change being a slightly higher pro­ in the fish caught there (Plate IV) which as a portion of fish of west coast origin. On this smolt was only one year old. occasion the nets were set between two commercial The results of this Loch Inchard experiment are bag-net stations and any fish migrating southwards in striking contrast to those of earlier years. The were immediately faced with a succession of majority of fish have not remained near the place stations down to, and including, the Island of Skye, of marking but have made considerable journeys. but the shore to the north and at the west end of Although the marking station was on the west coast the north coast was again clear of nets. 37. y.

W lCKl

I t » ' \ 7 i

PERTM i

a >

Fig. 10

— 29 — (III, 2)

Plate III, a 5 y2 lbs; 27 ins; marked at Melvaer off Sognefjord 10/7/37; recaptured River Forth 5/8/37.

Experience gained in the Moray Firth and at spawning ground. The recaptures made in these Thurso would suggest that a considerable pro­ nets are in consonance with these facts in that a portion of the marked fish which belonged to few marked fish were caught all the way down to rivers within at least fifteen or twenty miles of Skye. The number so caught — 21 fish — (36 % the place of marking would be caught in the of all recaptures) was not great but is not out of commercial nets which were set to the south of Rhu proportion to the known stocks of the various Stoer. None of the rivers of this part of the west districts. No great aggregation of recaptures such coast are comparable to the larger and more im­ as was experienced in earlier years could be portant salmon rivers of the east coast but some, expected and, if such had actually occurred, then e.g., Laxford, Inver, Ullapool, Ewe hold a quantity it would be clear that fish of only local origin of salmon which is limited only by the size of the could not be involved. rivers and the extent and quality of the available The Loch Inchard nets in 1936 were really — 30 —

Plate III, b. 9 lbs; 76 cm; 29/4/21; Typical Forth fish; 2-2. within the local cruising range of salmon from the cipation was realised: as already stated from Loch Laxford and a few minor streams on the west coast. Inchard three fish went north and east for every The Rhu Stoer station is still within the radius of one that went south while now from Rhu Stoer movement of the Laxford fish but in addition it is three salmon are found to go north and east for within the area of those from the Inver, Kirkaig, every two that remain on the west coast. Ullapool and Broom. Consequently a greater pro­ The west coast recaptures in 1937 were scattered portion of fish of these rivers might be anticipated all the way down to Skye and then an isolated fish at Rhu Stoer than at Loch Inchard. This anti­ near the south end of Mull. None of the marked - 31 — (III, 2)

Plate III, c. 6^4 lbs ; 621/2cm.; Marked Loch Inchard 1/7/36; recaptured Forth 10/7/36. fish went to Norway and as the others were grouped sea growth of the Tweed trout is much more rapid in very similar fashion to those of 1936 it is than that of any other sea trout in Scotland and, scarcely necessary to recapitulate the details here: so far as is known, in Great Britain is only they will be found on the map on Figure 10. It is equalled by the- growth of the- trout from the sufficient to note that on the east coast the most neighbouring rivers Ain and Coquet. The marked southerly salmon was found in the Forth and that a trout weighed 81/2 lbs. and was 71 cm. long, but sea trout, marked at Rhu Stoer, was netted in the had spent only 1+ years feeding in the sea: Tweed. This last is of particular interest since the knowing its size and age one could say with — 32 —

Plate IV. 4 lbs. 24 ins; marked Melvaer off Sognefjord 11/7/37; recaptured Tweed 9/8/37. (Part of adult fish scale). certainty that it could belong only to Tweed, Ain a minority belong to the west coast with compara­ or Coquet. tively few native of the rivers near (within thirty Summarised shortly the 1937 results confirm miles) of the place of marking. those of 1936 and show that the majority of fish on In supplement of these definite records of the coast even thirty miles south of Cape Wrath marked salmon we have information regarding the belong to north and east coast rivers and that only capture of a certain number of salmon by trawlers ISLANDS

XX

Fig. 11

- 33 — (III, 2) working out at sea. Such records, however, are the Moray Firth to the Firth of Forth and off the necessarily extremely fragmentary and are spread middle west coast of Scotland also. But in spite of over a long period (from 1890): for some years a the intensive fishing of all kinds off the British special enquiry has been made for such captures coasts salmon are never caught in such quantities but, rare as they are, it is probable that not all or at such stages of their life as to suggest anything have been reported partly owing to lack of know­ like a congregation of growing fish gathered ledge on the part of the captor of the request for together in a selected feeding area. the information and partly because an impression No reason exists for believing that the fish exists that the capture of the fish is illegal ■—- so which are recorded on the chart on Figure 11 much is the latter the case that the salmon are were not all either adult fish on their way to fresh almost invariably eaten on board the trawler and water or, in a very few instances, kelts returning to are not landed for the market. sea: no evidence of recent feeding was obtained in For what they are worth the areas where such stomachs as were examined. They are spread captures have been reported are shown in Figure 11. out over a very wide area, they were caught over The positions indicated follow roughly a line drawn a large number of months in the year and nothing up to thirty or forty miles off shore from the suggests a particular congregation at a particular Islands down to the Dogger Bank area. place at any particular season of the year. Even No concentration at any particular point is shown the smolts directly they leave the rivers are never nor is any route of migration demonstrated. The taken except when they are found in such predatory only interpretation that can be placed on the result enemies as saithe and conger eels. We are forced is that it represents a chance capture of the fish to the conclusion that once smolts or kelts reach while on their way to or from their feeding grounds salt water they move off without hesitation to a with origin probably in the east coast rivers of feeding ground at some considerable distance from Scotland although possibly they might belong to their point of departure. Professor Dahl found rivers of England or the continent. the smolt beginning to feed and grow off the Such then is the evidence in detail of the move­ Norwegian coast. We have no evidence of a like ments of salmon along the coasts of the northern happening off the Scottish coasts and indeed it is part of Scotland. It now remains to consider the possible that some of Professor D a h l’s fish were implications which it carries and the broad lines of Scottish origin on their way north. That feeding of interpretation which it allows. grounds for British salmon is in the North Sea First of all we have to consider if the salmon seems to be impossible. Were it anywhere in this has, at any time or at all times, inshore feeding intensively fished area the record of captures made grounds or if it feeds at considerable distances from by trawlers, and in herring drift nets, must have the coast. There can be no doubt that the salmon been infinitely greater during the last forty years we are now dealing with, and all those taken at than has actually been the case. Large sea trout commercial fisheries on the coasts of Scotland, are of a size comparable with that of smaller salmon on their way from their feeding grounds to fresh are known to feed on the coasts of Denmark and water when they are netted. Occasionally remains Holland and on the southern half of the English of food may be found in the intestine, very rarely coast. They are caught in all these areas. One food may be found in the stomach but in general can only presume that food adequate for these sea stomach and intestine are empty, the feeding period trout would be equally acceptable to salmon of the is finished and the fasting ante-spawning period same size and as illustrative of the absence of has commenced. Even if the fish be retained by feeding by salmon one has only to record the physical conditions in the sea long after they desire absence of this species from these areas. to enter fresh water, as in Thurso Bay in 1920, We may thus exclude the North Sea as a feeding feeding is not recommenced. If retained long ground for Scottish, or indeed any, salmon. We enough in the sea the salmon begin to lose weight have still to decide where they go, whether they and become red. In all the marking experiments frequent one area or several feeding areas and the not a single marked fish which has not shown light which the marking of salmon on the Scottish quite unmistakeable evidence of having spawned coast may shed on these questions. in the interval has been recaptured in a year We may first consider whether it is probable following that of marking. that the salmon of the rivers of thë continent, of If salmon frequented inshore feeding grounds the east and west sides respectively of Great they would be caught on baited lines as they are Britain, and of Ireland all go to the same food caught in the Baltic or they would be taken by source or whether they frequent different areas seine or trawl nets as soon as they were large perhaps relatively adjacent to each other or pos­ enough to be retained by the meshes of the net. If sibly separated by large ocean spaces. It seems they adopted a pelagic life when feeding they a little difficult to believe that the salmon of, for would inevitably be taken in the first spring and instance, the south-west of England and the south summer of their marine life in herring nets just as of Ireland can have the same feeding places as sea trout at the same stage of life are taken from those originating from the rivers of the Moray

3 — .'54 —

Firth, the south-east of Scotland or of Norway. areas of the scales and show that the fish concerned Scale investigations in Scotland have also shown conform with the known characteristics of the that the salmon of the rivers of the west coast, salmon of the coasts of Scotland to which they when all conditions are equal for both, make a travelled. In explanation of the variation in size definitely greater increase in length in their first as between 1936 and 1937 it should be added that year in the sea than do those from rivers of the the grilse of 1936 throughout Scotland were about east coast. The grilse of the east coast are earlier one pound heavier than normally. than those of the west coast, and at the same dates These facts would suggest that at least two the west coast grilse are larger than those on the separate feeding areas do exist even for salmon east coast. It might be said that this results from from such comparatively adjacent districts as the a difference in the primary size of the smolts or east and west Scottish coasts. How the salmon of that these are hereditary characters which are the rivers of the north coast fit into this division developed by the fish from the two sides of Scot­ has not yet been ascertained. I cannot, of course, land even if they are feeding and growing in the speak of Norwegian or other continental salmon. same environment. The only growth characteristic At first it would seem to be difficult to recon­ common to individual rivers on each side of Scot­ cile this separation of the feeding grounds with the land is produced by the original smolt length. The arrival of fish belonging to both coasts simultane­ sea growth responds to the smolt growth and the ously at one point such as Loch Inchard or Rhu longer smolt invariably produces the greater length Stoer. But this difficulty is not as insuperable as it at the end of any year of sea life. When we have seems since it is quite possible that in this area at the this feature as between fish of adjoining rivers it north end of the Minch salmon may strike in from seems impossible, if the fish of the two coasts of the north or north-west and at the same time others Scotland were feeding side by side, that they should may be diverted to the same destination from develop an altogether separate growth character­ feeding grounds further to the south, and possibly istic. If they were so feeding the only factor which further to the west also, by the imposition of the would produce a difference in the average length barrier formed by the from Barra at the end of the first year in the sea would be a up to the Butt of Lewis. difference in the average smolt lengths. For the In order to consider the matter further it will west coast salmon to be longer, the west coast now be most convenient to link together the various smolts would have to be longer. Whereas the west parts and stages of the marking programme during coast smolts are not longer than those of the east which 5073 salmon have been marked in the sea coast and indeed in certain rivers the reverse may be and 20 per cent, of these have been recaught. the case. The grilse of the Forth and Tweed are To do this to best advantage it will be most suitable larger than those of other east coast rivers, but to consider first the results obtained on the north­ their larger size is a factor directly connected with west and north coasts and then the earlier returns the time of their return (which is a month later on the east coast. than the average) and the extra feeding they are If the feeding ground of the east coast fish lie able to enjoy. But the larger size of the west coast immediately to the westward, or to the south of grilse cannot be accounted for in similar fashion westward, of Scotland then the Shetland—Orkney since they are longer than the east coast grilse at line of islands must inevitably exercise a very the common time of the end of their first year of definite, and controlling, influence on the run. The sea life and are always larger if west and east fish must be shepherded to the north of Shetland coast grilse taken at the same dates be compared. or through the Fair Isle channel or through Pent- This variation in the size of the grilse from the land Firth. If large numbers came through by this two sides of the country can be used as a check last route then not only would commercial stations on the origin of the grilse which were marked in on the shores in the vicinity be very remunerative 1936 and 1937. If the movements represent a but also large numbers would be seen round the definite homing migration and are not merely Shetland and Orkney Islands in the summer and erratic wanderings then those retaken on the west many would turn into Thurso Bay. Our marking and east coast respectively should conform to the experiments in the last named area would have rule which has been deduced from the independent demonstrated their presence and the sight of fish examination of scales from rivers from each side jumping round and among the islands would have of the country. The particulars are as follows: — been reported. In point of fact fish are not seen Length at end of 1st Size, round the island shores and the Thurso Bay year in Sea marking produced no evidence at all of any West East. West East, cm. cm. Wgt. Lgth. Wgt. Lgth. dominant migration eastwards. Nor are the com­ lbs, cm. lbs. cm. mercial nets on the eastern half of the north coast 1936 Loch Inchard. 50- 49- 6-6 67- 5-5 63- unusually plentiful or unusually successful. A 1937 Rhu Stoer. .. 46-5 43-5 6-2 65-5 4-2 57-5 westerly feeding ground would also cause many These figures amply confirm the evidence of the fish to come in south of Barra or through already obtained from the examination of the parr one of the sounds in the Outer Hebrides. This — 35 — (111, 2) would result in a congregation of salmon in the proportion move in this direction than by the Minch of which the commercial netting along its westerly route. shores gives no sign. Any considerable quantity of We are not yet in a position even to make a salmon passing close to the land or in narrow surmise as to where a separate feeding ground for channels of the outer islands, in the summer time salmon from west coast rivers may be. It is hoped when they show themselves freely, must inevitably that it may be possible to mark salmon this year have been noticed here as it would have been in on the west coast at a position to the south of Skye. Shetland and Orkney, by those frequenting the Results from here may shed some light on the coasts. They are never seen and on all counts a problem. westerly feeding ground would, therefore, appear Once within the confines of the North Sea it to be improbable. would appear that the fish move southwards clear The same arguments as well as those suggesting of the coast and only approach close inshore when captures during the feeding period apply against a relatively near their own rivers. Commercial feeding ground only slightly to the north of Scot­ netting results, however, suggest that there may be land. We are driven to the conclusion that the a few centres where fish strike the coast far from salmon must arrive from some considerable distance their own rivers and then re-distribute themselves. to the north or north-west, and probably the latter, Such points are possibly near Tarbet Ness, to the of the British Isles. From this area the Shetland— south of Aberdeen and near Montrose but no work Orkney line would still provide an important factor has yet been done to elucidate the questions which but it would divide the fish more surely in the arise at these points. Our own marking results general direction of their destination. If anywhere show that within the confines of the Moray Firth on the borderline they would be more likely to there is only a limited movement, towards the take the correct side of the land or proceed east­ rivers, which may be roughly in the general direc­ wards through the Fair Isle channel and east coast tion of the prevailing eddy tide running inwards salmon would not be concentrated at the easterly from Burghead and then upwards along the Ross end of the north coast. At the same time such and Sutherland coast. It is quite possible, however, division cannot be perfect, especially if fish came that there are two lines of approach to these Moray from far to the westward, say in the general direc­ Firth rivers, the one direct from the north or tion of Iceland, and the outer edges of the fan through the and the other from shaped (as one must suppose it) wave of migration southwards by fish which have come down the to the east coast may quite readily and naturally centre of the North Sea and have then turned in, reach the western end of the north coast and the somewhat late, towards the coast and their own northern end of the west coast. It is equally pos­ waterways. Such a possibility is supported by the sible that salmon belonging to rivers of the north recaptures of kelts marked in the Helmsdale and and west coasts should make at landfall at the east referred to on page 19. Very few fish natives of end of the north coast or pass eastwards of the rivers further south penetrate into the inner part Shetland—Orkney group and then re-set their of the Moray Firth. It is possible that these are course. A very few recaptures of marked clean fish fish which have approached through the Pentland support this possibility and we have certain ex­ Firth and thereafter are clinging more closely to amples of west coast fish on the north coast, as the coast than do those which come down through for instance one clean fish from Thurso Bay as the main Shetland—Norway channel. well as kelts marked in the Barvas and Grimersta (west side of Lewis) wrhich were recaptured when again clean fish in Thurso Bay and the Carron Bibliography. kelt recaptured at Melvich. Supposing this far north-westerly origin one The following papers in the Fisheries, Scotland, Salmon may anticipate that the vast majority of salmon Fisheries series of the Fishery Board for Scotland:— destined for east coast rivers would set a suffi­ C a 1 d e r w o o d, W. L. ciently accurate course to pass to the east of the Sea Netting Results, 1913 No. I. Shetland—Orkney line. When one looks at the Sea Netting Results, 1914 No. III. chart it is less surprising that some should touch Sea Netting Results, 1915 No. I. the Norwegian coast before reaching Scotland, as Sea Netting Results, 1920 No. I. Professor D a h l’s work has shown to be the case, Results of Salmon and Sea Trout Marking in Sea and than that others should be as far west as Cape River, 1922, No. I. Wrath. That five recaptures have been made in M e n z i e s, W. 1. M. Scotland from the limited number of salmon The Movements of Salmon Marked in the Sea, 1937 No. I. marked at the Sognefjord suggests that a far higher The Movements of Salmon Marked in the Sea, 1938 No. I.

3'