scheme the sewage and industrial waste which previously entered the Water of Leith, including the district as far inland as Balerno, is carried to the sea, while by a separate system of rain-water drainage the innocuous waters are conveyed to the stream by way of compensation.

Similarly, the drainage of Aberdeen has been carried to the south of the River Dee so as to discharge at Girdleness on the coast.

I recollect that some years ago when the pollutions from the River Don paper mills were complained against, and before the opening up of the serious obstructions in the river, a proposal was made to pipe the whole of the impurities to the sea, a distance of several miles. In the case of one of the two districts in Scotland from which salmon have been totally debarred through pollutions, it is possible that an expedient of this kind would have saved the river.

It is of the utmost importance that whenever possible highly toxic effluents such as gas-liquor, tar compounds, acids, sulphite cellulose products, chlorine and other bleaching fluids, &c., should be kept out of our rivers altogether. I venture also to reiterate that if such poisons are run into rivers by those interested in certain industries, the result is the certain destruction of the salmon fishing industry on the coast as well as in the rivers. The fish caught upon the coast have to be bred in the river.

INSPECTION IN 1927.

My annual tour of inspection took me first to the Loch Lomond district, then across Rannoch to the Tummel, then to Aberdeen and the rivers flowing north into the Moray Firth, down the Caledonian Canal to Spean Bridge and Fort William, and thence to Connel Ferry and Edinburgh.

Loch Lomond.-Records of the rod catch have been kept for a period of fifteen years. It is not held that these are absolutely complete, but that with the careful reporting of catches from all recognised boats the records are as accurate as possible, and, for purposes of comparison, may be regarded as uniform. Taking the records for salmon (and grilse) and for sea trout, in quinquennial periods, we have the totals:

Years.

1913-17

1918--22

1923-27

The increase of salmon in the last five years is remarkable. The Endrick is the principal river flowing into Loch Lomond, so far as the breeding of salmon is concerned, the Falloch at the head of the loch having an impassable fall. The Endrick has a serious fall at Gartness with a pool below, called the Pot of Gartness, which has attained some celebrity as a place where the salmon snatcher is busy in the autumn. A considerable number of fish manage to ascend the fall, after which they have to negotiate a dam dyke just above the village of Gartness. This is not a very serious obstruction when the level of water is suitable, but the danger to fish when checked in their ascent is that at such points gangs of poachers are able to find them. I am informed that people come all the way from Glasgow in order to snatch fish from this river.

There are several miles of admirable spawning ground in the upper reaches, and also there is some good ground some distance below Gartness which can be occupied by late-running fish.

The Loch Lomond Angling Association act virtually as a fishery board, and deserve and require all the local support that can be given them. If it were possible to have at quick call some local bodies of special watchers recruited from gamekeepers and ghillies who could deal with the poaching fraternity, very many spawning fish might be saved to the river. A local company of the kind suggested, who would be sworn in as water bailiffs, would be able to deter poaching by their presence, and would be able to turn out and meet at any desired spot long before any assistance could be expected from Loch Lomond. The usual watchers of the Association are not sufficiently numerous to permit of a number being stationed on the Endrick, nor can they entirely neglect other parts of the Loch Lomond area. Amongst the salmon taken in the loch in 1927 was a fish of 35 lb. The record fish was killed in 1912, and weighed 42 lb.

Lochy District.-In this district my special interest was to view the development of the Loch Aber Water Power Scheme, which I did chiefly from Spean Bridge.

Although extensive powers have been acquired by the British Aluminium Company for the abstraction of water, not only from Loch Treig, but from Loch Laggan and even the head waters of the Spey through Loch Laggan, the scheme as at present preparing will not touch the Loch Laggan flow. The tunnel under construction from Loch Treig to Fort William is 15 feet in diameter, and at one part some 300 feet below the surface of the shoulder of Ben Nevis. It may be anticipated that when the intake is opened and the 15 miles of tunnel are completed, the River Spean will no longer receive any water from the Loch Treig source, yet the Loch Laggan supply will continue, and on this account the very serious view formerly taken as to the future of the Spean requires some modification. The Spean will then contain not merely the water of the Roy tributary from the north-which is untouched by the scheme-but the head supply direct from Loch Laggan.

I find that, in view of the consideration just stated, angling tenants are renewing leases from the Abinger Trustees. The creation of Inverlochy village just north of Fort William, in connection with the British Aluminium development, is now well advanced, and the sewage arrangements have received careful consideration from the Scottish Board of Health in consultation with this Board. The Lochy near its mouth is subject to a good deal of alteration in times of flood; indeed the whole course of the river from Gairlochy downwards is in an alluvial deposit of rather loose gravels, and has been so altered in the last twenty or thirty years that former pools are now gravel banks, while former crofts and farm lands are occupied by the course of the river. Owing to the low level of the new Inverlochy village gravitation purification of the sewage is not feasible, but arrangements have been so made that solids will be screened and the outfalls placed in the -tidal waters, where we are assured no harm will result.

W. L. CALDERWOOD,

Inspector of Salmon Fisheries for Scotland.

H

REPORT OF ASSISTANT INSPECTOR OF SALMON

FISHERIES.

Researches into the life history of both salmon and sea trout were continued during the year 1927. Owing to financial restrictions the work was more limited in scope than during recent years, and after the end of March it was confined to the collection and examination of scales and statistical data. The routine salmon work has been carried out on the lines already laid down, and the examination of sea trout scales, which was supplemented by some marking experiments in the early months of the year, has again been undertaken on a voluntary basis by Mr. G. H. Nall.

I. SALMON.

(a) Scale Investigations.

The chief concentration has again been on the Spey and Dee material already on hand. The results obtained from the catch of both rivers in 1924 have been published and the conclusions reached from the 1925 run of salmon in the Spey are in the hands of the printer. As stated in my last report, certain preliminary findings deduced from a comparison of the results obtained for the first three years of the investigation, 1921 to 1923, have been published. A more complete review of the generation of salmon in question in each river will be possible after the scales collected in the Dee in 1925, and at present under examination, have been finished; it is hoped that this work will be overtaken during the current year.

It was felt that before this final review was made some material which would form as close a comparison as possible with the two main rivers should be collected and examined. Arrangements were accordingly made for scales and measurements to be taken from salmon caught by sweep net at the mouth of the Conon during the netting season of 1927; these scales were read under the microscope towards the end of the year, and the figures obtained therefrom with accompanying text are now in course of preparation for the printer. This addition to the programme has been well justified by results. The Conon in much of its course is not unlike a miniature copy of the Spey, with the essential difference that its upper waters do not rise in such high ground, while a number of lochs of considerable total area act as regulators of temperature and flow. One would consequently expect the average age of the smolts at migration to be lower in the Conon than in the Spey, whereas we now find the contrary to be the case; over half of the Conon parr are three years of age before they leave for the sea, and the proportion of those four years old has only been equalled in our previous researches by the salmon of the Grimersta. The rate of growth in the sea is also relatively high in the case of Conon salmon, and is quite comparable with that of the Grimersta fish.

With a view to widening our knowledge of conditions of life in districts rather distant from areas which so far have been under observation, arrangements have been made for scales and the relative fish sizes to be taken in the Thurso and in the Solway Dee during the current year.

(b) Marking.

No marking, as such, was done during 1927, but labels were affixed to a few fish taken incidentally when netting for sea trout in South Uist in February and March. A few among these were interesting since they were found to have come up from the sea as small spring fish and probably at a date earlier than clean salmon are locally supposed to inhabit the Howmore waters where they were taken.

(c) Salmon caught at Sea.

In recent reports mention has been made of a small number of salmon taken at sea at some distance from the coast; these details I am now able to supplement with particulars of some fish caught during 1927. The majority were taken in only two catches, and they were only had at second-hand as it were, since they were found in the stomachs of sharks brought on board a trawler in the ordinary course of fishing operations. In February 1927 a shark 15 feet long taken by a trawler working six miles E.N.E. of Aberdeen had in its stomach eight salmon, three cod and one saithe, while a smaller one, only 10 feet long, caught in March ten miles S.S.E. of Aberdeen was found to have recently consumed three salmon. Three other clean salmon and their places of capture may be detailed: :

19 lbs. Feb. 9 miles S.E. of Aberdeen.

12 lbs. March. 4 miles off Sandside (Caithness).

6 lbs. April. 12 miles N.N.E. of Enniberg (Faroe).

The second is of some slight additional interest since it was taken by a Danish seine net. The other two were taken by trawlers, as were four dead kelts taken in November six miles E.N.E. from Aberdeen off the mouth of the Don. Two of these four fish were taken in one drag and one in each of two other drags. They were found immediately after a strong breeze of wind, and the suggestion was made that the sea at the mouth of the river was too heavy for them and that they had been killed. Other possibilities occur to one, but unfortunately the fish were not brought ashore nor was the sex determined.

In addition to the salmon, I have information of two sea trout taken offshore in February. One of 11 lbs. was taken four miles S.E. of Cove (Aberdeenshire), and the other, a kelt of 1 lbs., on the Outer Scourie Bank off the west coast of Sutherland.

II. SEA TROUT.

(a) Scale Examination.

Soon after the intensive study of sea trout scales was started it was clear that the lives and types of growth differed so markedly not only between the fish of different parts of the country, but it might be even between the sea trout of rivers not far distant the one from the other, that a wide survey would have to be made, and that attention could not be concentrated on one or even a few districts as was the case with salmon for at least the main outlines of their lives. During 1927, therefore, Mr. Nall has devoted himself

to sea trout of both east and west coast districts, with the gratifying result that four papers by him have just been published or are on the point of publication.

Sea trout of the Findhorn and Ugie are not unlike those of the Don and Ythan; they present the same difficulty of scale interpretation, which is even intensified in the case of examples from the Spey on which some preliminary work has been done. The zone on the scales representing the winters during sea growth is often hard to detect, and in very many cases can only be termed a winter zone by courtesy, since it is so often formed in March or even in April; in fact in many districts of the west, as well as the east, coast this seems to be the case, and while "winter zone is a correct term for the aggregation of close ridges on a salmon scale, it would appear that "slow growth zone would be of more appropriate application for sea trout.

As the Findhorn and Ugie trout resemble those of the Don and Ythan sea trout, so do those of the West Ross Carron resemble in a general way the Ewe fish, both in their scale formation and in type of growth. The smolt age may be slightly higher in the Ewe than in the Carron, just as the Carron trout may grow slightly more vigorously in the sea, but in general both belong to what Mr. Nall has called the West Highland type, with only those local differences which are so characteristic of the species.

A great deal of Mr. Nall's time has been devoted to a collection of over 1,300 sets of scales and particulars from South Uist districts. These scales fortunately presented far fewer difficulties in interpretation than do those of the East Coast, and at the same time they have revealed features differentiating the life of these island trout from those of the mainland. The island fish grow fast, extraordinarily fast in many cases, do not usually attain the relatively considerable age of the large mainland fish, and, rather as a corollary of this last fact, they have but few spawning marks on their scales. The paucity in the number of spawning journeys is also connected with the fact that some of the fish may pass even four post-migration winters before starting to spawn, and that a break in the sequence of spawning operations is less rare than in mainland rivers.

(b) Marking.

The only marking undertaken during the year was in February and March in South Uist. As a whole it was not unsuccessful. Valuable scale material and information were obtained from the Howmore and Kildonan systems, and have since been supplemented by the return of marked fish, but efforts in Loch a' Bharp met with smaller reward. In this last loch, mud, weeds, and rocks in their respective spheres conspired to make netting with any profit almost impossible, but a larger number of fish, although probably not quite a representative sample for the whole_water, was obtained in the tidal channel, the so-called "Bharp Pools,' between the loch and salt water. In the Howmore system I found an extraordinary collection of sea trout, ranging from almost 10 lbs. down to less than the same number of ounces; among them were clean and comparatively fresh run, clean but distinctly coloured, mending kelts and other kelts in all stages of recovery. The only type that was lacking was an absolutely clean run fish, and of its existence either here, in Kildonan, or in Loch a' Bharp, I could