SH 
 \CsT7 
 
 IC-NRLF 
 
BERKELEY 
 
 LIEFARY 
 
 UNIVERSITY OF 
 CALIFORNIA 
 
PAMPHLET ON STOCKING 
 
er 
 
ON STOCKING RIVERS 
 
 .. I 
 
 STREAMS, LAKES, PONDS 
 AND RESERVOIRS 
 
 WITH SALMONID^: 
 
 BY 
 
 SIR JAMES [MAITLAND, BART. 
 
 F.L.S., F.G.S. , F.Z.S. 
 
 FOURTH EDITION 
 
 Published by J. R. GUY, 
 
 SECRETARY, HOWIETOUN FISHERY, 
 
 STIRLING, N.B. 
 
 1892 
 
CONTENTS 
 
 OVA, THE PRODUCTION OF, . . 9 
 
 THE INCUBATION OF, . * 13 
 
 APPROPRIATE EMPLOYMENT OF, .15 
 
 COST OF, . 16 
 
 FRY, THE PRODUCTION OF, . 23 
 
 ,, APPROPRIATE USES OF, ... .35 
 
 ,, COST OF, 36 
 
 YEARLINGS, THE PRODUCTION OF, . 39 
 
 APPROPRIATE EMPLOYMENT OF, . . 40 
 
 COST OF, ... . 43 
 
 TWO-YEAR-OLDS, THE PRODUCTION OF, .' 47 
 
 APPROPRIATE EMPLOYMENT OF, . 51 
 
 COST OF, 51 
 
 EEDDS, ....... . 54 
 
 PONDS, . ... . -. . 57 
 
 CULTIVATION OF WATER, . ... 62 
 
 TRANSPORT OF TROUT, ... 64 
 
 APPENDIX I., PRELIMINARY REPORT ON A NATURAL 
 
 LAKE, .66 
 
PAMPHLET 
 
 ON 
 
 STOCKING 
 
 FOURTH EDITION 
 
 HOWIETOUN, January 31 st, 1892. 
 
 THE last edition of the pamphlet on Stocking 
 has been out of print for some months, while this 
 issue has been delayed through the pressure of 
 other work, and the necessity of practically re- 
 writing the pamphlet to bring it up to date. 
 
 The first edition had to beg the whole question 
 of modern fish-culture, the fourth edition finds 
 artificial Stocking very generally adopted, and 
 trout farms established in many places in England 
 and Scotland as purely commercial ventures, 
 thriving both fishcultu rally and financially. 
 
 The public, at least the angling portion thereof, 
 is already very much up to date on the subject, 
 the size and colour of eggs, the length and shape 
 of yearlings or two-year-olds, are questions on 
 which it holds a very decided opinion, nor is 
 it any longer necessary to point out, as in the 
 
8 On Stocking. 
 
 first edition of this pamphlet, the gain to be 
 derived from stocking neglected pieces of water. 
 The public wants to know what each pond, 
 lake, or mile of stream should yield to the rod 
 annually, and what species, kind, and description 
 of fish will give the best sport. 
 
 And the public is right, because when once 
 the capacity I might say the trout-bearing 
 capacity of any given piece of water is known, 
 the trouble and cost of cultivation can easily 
 be adjusted to produce the desired results, 
 whether for profit or sport. I use the word 
 cultivation advisedly, because many still believe 
 that they have only to purchase a large number 
 of two-year-olds, and that then everything 
 necessary has been done. Alas ! from a trout- 
 farmer's point of view, there never was a 
 greater mistake. .Of course, in the case of a 
 new reservoir, like the Lake Vyrnwy, the lately 
 completed reservoir for Liverpool, it is only 
 necessary to plant a sufficient number of two- 
 year-olds, or their equivalent in yearlings or in 
 fry, and the desired result is produced ; but 
 in the case of ponds which have existed from 
 time immemorial, and in the case of streams, the 
 pre-existing conditions control not only the size of 
 trout required for the Stocking, but the mode of 
 cultivation to be followed to enforce successful 
 results. 
 
On Stocking. 9 
 
 To enable the reader more easily to under- 
 stand the practical rules which govern the suc- 
 cessful cultivation of trout in ponds, lakes, and 
 streams, it will be convenient first to consider the 
 the cost, manner of production, and uses of Ova, 
 fry, yearlings, and two-year-olds ; next in order 
 the various conditions under which each can be 
 most profitably used ; and finally, how any given 
 piece of water can be cultivated so as to yield 
 conditions favourable to one or other mode of 
 Stocking, and the management necessary to com- 
 mand the best possible results. 
 
 OVA. 
 
 7/5 Production, Incubation, Appropriate Employ- 
 ment, and Cost. 
 
 THE PRODUCTION OF OVA. Most anglers would 
 ask, ' What can be said of the production of Ova ? 
 why not net the spawning grounds ? ' But a 
 very great deal can be written on the production 
 of Ova, and much that is new. It is all very well 
 to net the spawning grounds. And if you know 
 of several brace of magnificent spawners, and the 
 owner of the water will permit these being netted 
 and stript, well and good, the Ova are most 
 excellent, and if half the fry resulting therefrom 
 are returned to the water, well and good, both 
 
io On Slocking. 
 
 owner and fish-culturist benefit, although when 
 the cost of men's lunches, and nets, railway fares, 
 and blank days are totaled up, the eggs seldom 
 cost much under twenty shillings per thousand. 
 The production of Ova, properly speaking, requires 
 as much skill as the creation of a herd of pedigree 
 cattle. Some good work may result in favoured 
 waters from spawn promiscuously obtained ; but 
 the best results can only be ensured by the most 
 careful adjustment between the class of spawners 
 from which the Ova is obtained, and the nature of 
 the stream, pond, or lake the produce of the eggs 
 are intended to stock. To place the fry from eggs 
 counting 25,000 to the gallon into high mountain 
 tarns or rocky rivers is to court failure there is 
 not food enough in such places all the year round, 
 to sustain such fast growing trout. Nor will 
 much better results follow the planting of the 
 produce of wild fish spawned promiscuously as 
 they come to net in sheltered lakes or deep slowly 
 flowing streams, where food is abundant, and fat 
 trout or coarse fish numerous. The slow growing- 
 produce of small wild fish are, from their less size, 
 subject to the cannibalistic attentions of the 
 existing older stock for many months longer than 
 the quick growing produce of wild breeders which 
 have been carefully selected, or the produce of 
 pedigree trout, whose age and parentage are 
 known with scientific accuracy. 
 
On Stocking. 1 1 
 
 The produce of breeders when confined are 
 looked on with distrust especially in Germany ; 
 and we think with much reason, if and where 
 the breeders are wild fish caught and confined 
 for spawning purposes, for the same reason that 
 wild animals in zoological gardens are unsatis- 
 factory as breeders. 
 
 But when the trout are domesticated, per- 
 haps for four or five generations, when their 
 characters are studied, and when individual 
 trout are as well known as prize rams, or a Field 
 trial setter and their parentage not one whit 
 more uncertain when, in fact, they are not only 
 domesticated, but bred to points in the same 
 manner as a Clydesdale or a short-horn, the 
 fish-culturist gains the power to produce eggs 
 of varying qualities, and selects those best suited 
 to whatever water he desires to stock. The con- 
 finement of the breeders ceases to be a makeshift, 
 and becomes a primary factor in improving and 
 adapting the race of trout to the high standard of 
 modern necessities and modern requirements. 
 
 The production of Ova thus comes to depend 
 on the establishment of a trout farm, farmed on 
 scientific principles, and containing ponds large 
 enough and deep enough for the heaviest 
 spawners. The ponds must be numerous, so that 
 the various ages may be separated, and it is 
 advantageous even to separate the sexes of the 
 
12 On Stocking. 
 
 older trout. Males do not fight if there are no 
 spawners to fight about, and the ugly wounds, so 
 prevalent in autumn and so fertile a source of 
 disease, are conspicuous by their absence. 
 
 Sufficient ponds having been provided, the 
 strain of trout requires to be obtained from 
 selected breeders, selected yearlings, selected 
 two-year-olds, and again selected three-year-olds. 
 After this fourth elimination of the less fit, the 
 trout may be allowed to grow for two seasons, 
 after which they are fit for spawning and the Ova 
 are of good size; but the best and almost the 
 largest Ova are yielded in the seventh season. 
 The Ova in the eighth are very slightly larger, but 
 the impregnation is not so perfect, and the number 
 of Ova per pound of trout is less. The next 
 season the Ova are still very good, but the 
 number per pound is sensibly smaller, and per- 
 centage of impregnation perceptibly lower. We 
 believe the lowering of the percentage of impreg- 
 nation in very old trout is due to the thickening 
 of the shell of the Ovum. 
 
 It is necessary to have a series of ponds for each 
 strain of trout, although so many ponds are not re- 
 quired for ordinary strains as for the selected pedi- 
 gree breeders, nor is it necessary to size the breeders 
 so frequently, but it is a mistake to suppose that 
 the same class of ponds are suited to all strains of 
 trout. Some prefer the water to flow in as a 
 
On Stocking. 13 
 
 stream ; others thrive better if the water falls into 
 the pond over a perpendicular inlet. Char live in 
 deep -shaded ponds, narrow and constructed east 
 and west, so that the south side gives shade at 
 all times, while they die only too freely if the 
 pond runs north and south, and is difficient in 
 shade. We have found S.fontinalis thrive, how- 
 ever, in a deep, narrow pond, with perpendicular 
 sides running north and south, this pond is well 
 shaded by overhanging trees ; while in two similar 
 ponds, not so shaded, the loss both in spring and 
 after spawning is very heavy. 
 
 The production of Ova also includes the intro- 
 duction of fresh blood and the production of 
 fertile crosses. There are now at Howietoun 
 many thousand yearlings whose pedigree shows 
 one-eighth salmon blood and seven-eighths trout 
 blood. And we have reason to believe that this 
 cross will prove perfectly fertile inter se although 
 the higher proportions of salmon blood have been 
 very largely infertile ; but this subject will be 
 more fully recorded and discussed in the second 
 part of the history of Howietoun. 
 
 THE INCUBATION OF OVA. The strength of the 
 fry is controlled by the mode of incubation of the 
 Ova. The best Ova from the best strain of trout 
 may easily be so treated that the resulting fry are 
 puny and ill-conditioned ne'er-do-weels. There 
 
14 On Stocking. 
 
 are three secrets of incubation, these are : no 
 strong light ; no sudden change of temperature ; no 
 stagnant water. Strong light injures the nervous 
 system ; sudden change of temperature injures 
 the veinous system ; stagnant water injures both. 
 The light can be controlled with a little care ; the 
 even temperature can be insured by incurring some 
 expense. But to render the eggs secure against 
 stagnant water requires both great care and much 
 expense. The hatching trays must be so arranged 
 that a current of water is constantly impinging 
 on each individual ovum and sweeping off (the 
 pores of the shell) the carbonic acid continually 
 produced during the formation of the embryo, 
 but more particularly in the few weeks immedi- 
 ately preceding hatching. 
 
 Many designers of hatching apparatus seem to 
 have had in view merely how to obtain the 
 greatest results on paper, the value of these 
 results does not appear to have received much 
 consideration. This or that apparatus will incu- 
 bate, and perhaps actually hatch so many thousand 
 eggs, and it requires little water and takes up next 
 to no space ! The important question, what is to be 
 done with the fry, never seems to have occurred 
 to the designer. Now the fact is that the fry 
 require nearly two square feet of surface per 
 thousand if they are afterwards to be fed in the 
 hatching troughs, and fully one square foot of 
 
On Stocking: \ 5 
 
 surface if they are merely to be retained until the 
 absorption of the yolk-sac. But this space is 
 sufficient for double that number of eggs ; there- 
 fore there can be no real inducement to design 
 hatching trays to incubate an excessive number 
 of eggs in the smallest possible space. However, 
 the practice of over- crowding trout and salmon 
 eggs is general, and to this practice many of the 
 disappointments encountered in private hatcheries 
 are due. If the eggs are so incubated that a cur- 
 rent of water perpetually cleanses each egg during 
 the whole process, strong fry is the result ; if not, 
 the contrary obtains. 
 
 APPROPRIATE EMPLOYMENT OF OVA AS A 
 MEANS OF STOCKING. Ova is now generally for- 
 warded 011 the point of hatching, and for those 
 who have troughs suitable for rearing alevins to 
 the feeding stage, or fry for four or five weeks 
 longer, nothing can be better than fully eyed 
 Ova laid on temporary trays, or on the bottom of 
 the trough. Only if fully eyed Ova is laid on the 
 bottom of the troughs, certain precautions are 
 necessary, as the embryo is very easily suffocated 
 drowned in fact in still water. These precau- 
 tions are first, to spread the eggs evenly so that 
 no eggs lie on the top of others, or even touch 
 others latterly ; second, to lower the surface of 
 the water to within an inch of the eggs ; and 
 
1 6 On Stocking. 
 
 thirdly, to arrange the inflowing supply in such a 
 manner that the current cleanses the carbonic 
 acid from every egg the water being of course 
 raised to three or four inches depth so soon as the 
 eggs are well -on the hatch. If the troughs are 
 provided with trays or grilles, the eggs may be 
 spread on them and thus do away with the 
 necessity for lowering the water, but in any case 
 the supply of water should be equal to three 
 gallons per minute for each 10,000 eggs in any- 
 one trough, and this quantity may be safely 
 passed through any number of troughs not 
 exceeding five. But the most appropriate use 
 of ova as a means of stocking is by sowing it 
 down in redds. There are many lakes so remote 
 from railways and roads that practically it is im- 
 possible to convey a sufficient stocking of yearling 
 to them. In this case redds become a valuable 
 adjunct. There are few lakes that have not some 
 feeding stream suitable for naturally rearing fry- 
 here again a few redds, proportioned to the extent 
 of the rearing ground, should be used, thus ensur- 
 ing the best possible results at a minimum of 
 cost. 
 
 The construction of redds and the selection of 
 suitable places will be found at page 54. 
 
 COST OF OVA. The cost of Ova is composed of 
 two items one fixed namely, the cost of incuba- 
 
On Stocking. 17 
 
 tion, and the other, very variable. The cost of in- 
 bation is fixed for all trout and salmon Ova per 
 gallon, and for each class of Ova per thousand ; but 
 as the same space is required in practice for every 
 gallon (at Howietoun this space is two boxes), 
 while in different classes of Ova the number to the 
 gallon varies from 23,000 to 50,000, it is evident 
 that the space required per thousand, and the 
 consequent cost of incubation per thousand is 
 nearly double per thousand for eggs running 23,000 
 to the gallon to that for eggs running 50,000 to 
 the gallon, in practice the limits are first-class 
 salmon, 23,000; first-class trout, 28,000; eggs 
 from young salmon and grilse, 30,000 ; ordinary 
 trout, 40,000 ; well-bred trout, 32,000 ; ordinary 
 wild lake trout, 40,000 ; wild hill-burn trout, 
 50,000. Hill-burn trout can be improved to 
 produce eggs running 40,000 to the gallon. 
 
 The principal hatching house at Howietoun 
 cost a little over 3000, and as at present fitted 
 incubates 80 gallons of Ova. The cost of renewals 
 of hatching houses is about 14s. per annum, and 
 the proportion of wages is about 2 per week for 
 say 15 weeks, as in practice the house cannot be 
 all filled under five weeks, and the eggs require 
 about ten weeks for incubation. Moreover the 
 house and boxes are used for fry for a further 
 period of fifteen weeks. The calculation will 
 stand thus : 
 
1 8 On Stocking. 
 
 Interest on .3000 at 4 per cent., . . .120 
 Depreciation and renewal calculated on 80 
 
 gallons of Ova at 14s., ... 56 
 
 176 Half = 88. 
 Of which one-half is credited to use for fry 
 
 leaving to debit of Ova, . . . .88 
 Add Wages 40s. for 15 weeks, . . 30 
 
 118 
 
 Or, dividing by 80 gallons, 1, 9s. 6d., that is, 1, 2s. and 
 7s. 6d. per gallon respectively. 
 
 A slight reduction may be made on these figures 
 on the ground that a certain number of the boxes 
 can be used twice ; but as this interferes to some 
 extent with their being afterwards used for rear- 
 ing fry I have neglected this item. Now, 1, 9s. 6d. 
 per gallon is for good trout eggs running from 
 26,000 to 32,000 per gallon almost exactly Is. 
 per thousand and this may be taken as an ac- 
 curate base in calculating cost. The cost of a 
 smaller hatching house will probably be not less 
 than the proportional 37, 10s. per gallon, 1 the 
 labour, however, will be unduly increased, and, 
 unless the house is built of substantial masonry, 
 4 per cent, on cost will be too little to debit as 
 rent; and in all small houses the cost of the 
 water supply is so important an item, that unless 
 carefully considered before the construction of 
 the building is commenced, the cost of incubating 
 
 1 The prime cost of the Hatching-house per gallon is 3000, 
 divided by 80 gallons, or 37, 10s. 
 
On Stocking. 19 
 
 eggs is more likely to be over Is. per thousand 
 than under. 
 
 The second item is the cost of obtaining and 
 fertilising the Ova. I have had large experience 
 in obtaining salmon Ova, and in different districts 
 the cost varies. On the Forth there are many 
 blank days ; on the Tweed few ; and on the Tay 
 practically none. I think it is safe to assume 
 that the cost of collection of salmon ova may 
 average for the season anything between 3s. 
 and 10s. per thousand, while the 10s. figure 
 closely approximates the cost of collection of wild 
 trout Ova. Even at Loch Leven itself, in the 
 earlier days of my fishcultural work, the whole 
 Ova collected during the season, divided by the 
 whole cost of collection, more than once gave a 
 figure slightly exceeding the above estimate. Of 
 course, now, through long experience, Ova is 
 collected at the Loch at a much lower figure. An 
 accurate estimate of the cost, when the breeders 
 are confined, may be obtained by adding rent of 
 ponds, labour, food, and value of stock together, 
 and dividing by the number of eggs obtained. 
 
 At Howietoun, four ponds are devoted to pedi- 
 gree S. Levenensis breeders, ponds Nos. 9, 10, 11, 
 12. No. 9 pond has 840 sq. yds. of surface. Each 
 of the ponds Nos. 10, 11, 12, have 1500 sq. yds., 
 making 5340 sq. yds., or 1 acre, roods, 16 rods, 
 and 16 square yards of water surface; and each 
 
2O 
 
 On Stocking. 
 
 pond is from 8 to 14 feet in depth. These ponds 
 are laid out for the following stocking : 
 
 S. LEVENENSIS PEDIGREE BREEDERS. 
 SHOWING POSITION IN PONDS AS AT IST MAY. 
 
 Year. 
 
 Age of 
 Spawners at 
 1st Dec. 
 
 Pond 
 9. 
 
 Pond 
 10. 
 
 Pond 
 11. 
 
 Pond 
 12. 
 
 REMARKS. 
 
 1891, 
 
 7 
 
 5 
 
 3 
 
 * 
 
 89 
 
 87 
 
 85 
 
 No. 10 pond not spawned. 
 
 1892, 
 
 8 
 
 6 
 
 4 
 
 91 
 
 89 
 
 87 
 
 85 
 
 No. 9 stocked with pedigree 
 
 
 
 
 
 
 
 
 
 yearlings. 
 
 1893, 
 
 9 
 
 7 
 
 5 
 
 91 
 
 89 
 
 87 
 
 85 
 
 
 1894, 
 
 8 
 
 6 
 
 4 
 
 92 
 
 89 
 
 87 
 
 91 
 
 No. 9 stocked with selected 
 
 
 
 
 
 
 
 
 
 pedigree two-year-olds. 
 
 1895, 
 
 7 
 
 5 
 
 4 
 
 94 
 
 89 
 
 92 
 
 91 
 
 No. 9 stocked with pedigree 
 
 
 
 
 
 
 
 
 
 yearlings. 
 
 1896, 
 
 8 
 
 6 
 
 5 
 
 94 
 
 89 
 
 92 
 
 91 
 
 
 1897, 
 
 7 
 
 6 
 
 4 
 
 95 
 
 94 
 
 92 
 
 91 
 
 No. 9 stocked with selected 
 
 
 
 
 
 
 
 
 
 pedigree two-year-olds. 
 
 1898, 
 
 7 
 
 5 
 
 4 
 
 97 
 
 94 
 
 92 
 
 95 
 
 No. 9 stocked with pedigree 
 
 
 
 
 
 
 
 
 
 yearlings. 
 
 1899, 
 
 8 
 
 6 
 
 5 
 
 97 
 
 94 
 
 92 
 
 95 
 
 
 1900, 
 
 7 
 
 6 
 
 4 
 
 98 
 
 94 
 
 97 
 
 95 
 
 No. 9 stocked with selected 
 
 
 
 
 
 
 
 
 
 pedigree two-year-olds. 
 
 1901, 
 
 7 
 
 5 
 
 4 
 
 1900 
 
 98 
 
 97 
 
 95 
 
 No. 9 stocked with pedigree 
 
 
 
 
 
 
 
 
 
 yearlings. 
 
 1902, 
 
 8 
 
 6 
 
 5 
 
 00 
 
 98 
 
 97 
 
 95 
 
 
 1903, 
 
 7 
 
 6 
 
 4 
 
 1 
 
 98 
 
 97 
 
 00 
 
 No. 9 stocked with selected 
 
 
 
 
 
 
 
 
 
 pedigree two-year-olds. 
 
 1904, 
 
 7 5 
 
 4 
 
 3 
 
 98 
 
 1 
 
 00 
 
 No. 9 stocked with selected 
 
 
 
 
 
 
 
 
 yearlings. 
 
 1905, 
 
 8 6 
 
 5 
 
 3 
 
 98 
 
 1 
 
 00 
 
 
 NOTE. The age of Spawners at 1st December is taken as age next 
 birthday, that being within six weeks of actual age at spawning. 
 With this exception, ages are always counted as from the 1st of 
 January of the year in which the- fish commenced to feed, whether 
 hatched in the preceding month of December, or on or before. 
 the 1st of January of that year. 
 
On Stocking. 21 
 
 The preceding table at once forms the basis for 
 an estimate of the cost of the production of trout 
 eggs. The cost of the alternate stocking of pond 
 No. 9 is 125 for 5000 two-year-olds, and 55 for 
 5500 selected yearlings, or 180 spread over 
 three years (say 1894-5-6), making 60 per 
 annum. The labour required would be at least 
 two skilled men at 60; making 120 per 
 annum, and about forty weeks of two women at 
 10s. per week, opening shell-fish to feed the trout, 
 for unless the trout are properly fed they do not 
 yield good ova that is, 80 weeks at 10s., equal 
 to 40, making the whole labour bill 160 per 
 annum. The food bill for this number of trout of 
 the ages noted in the table would not be less than 
 40 tons of clams, their present cost at Howietoun 
 including carriage is just under 5 per ton. Thus 
 the food would average 200 per annum. The 
 water supply for these four ponds should not be 
 less than 2,000,000 gallons, and should average 
 about 3,000,000 gallons per diem. It is difficult 
 to place a value on this item, as so much depends 
 on the first cost of the reservoir and inlet works. 
 But taking this at one-tenth of a penny per 
 thousand 3,000,000 gallons represents 456, 5s. 
 per annum and the water supply which, for this 
 purpose, it must be a. supply of pure -water must 
 always form one of the largest items of cost in the 
 production of Ova. 
 
22 On Stocking. 
 
 The two items remaining are rent and manage- 
 ment, if the cost of construction is considered 
 part of the water supply, and is included in 
 the moderate calculation of one-tenth of a penny 
 per thousand gallons. The ponds, with the 
 necessary ground between and around them, will 
 require between two and three acres, and the in- 
 terest of cost of roads, fences, and buildings, 
 mincing machinery, etc. , falls to be treated as rent. 
 I do not think that less than 30 per annum can 
 be calculated on, omitting management, risk, and 
 profit, the balance will stand : 
 
 Per Annum. 
 
 Stock, . . . 60 
 Food, . . 200 
 Labour, . . . 160 
 Rent, . . . 30 
 Water supply including con- 
 struction of ponds, . 456 5 
 
 906 5 or say 900 
 
 The estimate yield of good Ova is 150 gallons per 
 
 annum, which at Q per gallon is . . 900 
 
 But if only 100 gallons are obtained, and without 
 good management this is not improbable, the cost 
 rises to 9 per gallon, since 100 gallons at 9 
 per gallon is, . . . . . 900 
 
 If the annual cost of water and the four ponds'are 
 found by taking 4 per cent, on the cost of construc- 
 tion, and adding 10 per cent, for renewals, which, as 
 the ponds require clean earth on the bottom and 
 sides every fifth or sixth season, is not too high a 
 
On Stocking. 23 
 
 percentage, the sum estimated will rather be 
 increased than dimished. 
 
 When Ova are obtained from private ponds or 
 lakes, my experience is that the cost of collection 
 is much above the highest figure brought out 
 above, viz., 9 per gallon. This, with the 1 , 9s. 6d. 
 per gallon, 1 brings the prime cost of eyed Ova to 
 10, 9s. 6d. per gallon, or at 30,000 to the gallon, 
 6s. 6d. approximately. When the risk, cost of 
 packing, freight, and management are considered, 
 I am of opinion that first class Ova will tend to 
 improve in price. The present wholesale price, 
 including delivery, viz., 37, 10s. per 100,000, 
 being exactly 7s. 6d. per thousand. 
 
 I have given those estimates in the above form 
 chiefly in answer to many inquires from members 
 of District Fishery Boards, many of whom it was 
 impossible to answer fully by letter. 
 
 FRY. 
 
 Its Production, Appropriate Uses, and Cost. 
 
 THE PRODUCTION OF FHY. Salmon or trout 
 fry may be produced by forming artificial spawn- 
 ing ground in connection with rivers, lakes, or 
 ponds. In salmon districts there generally exist 
 many natural spawning places inaccessible to 
 salmon. The introduction of salmon to these 
 spawning streams can usually be successfully ac- 
 complished by opening the upper waters through 
 
 1 See page 18. 
 
24 On Stocking. 
 
 the removal of obstructions or construction of 
 passes. And beyond all doubt in most cases 
 a great public benefit would accrue. Be that 
 as it may, in Scotland at least, many hundred 
 miles of excellent spawning ground is annually 
 wasted, as far as salmon are concerned. The 
 power and the inducement to open up these 
 spawning grounds is a matter for legislation, and 
 in questions of salmon rights, legislation moves 
 but slowly. The interference with existing rights, 
 the absence of right of salmon fishing in the 
 riparian owners of the as yet salmonless waters, 
 and the difficulty of assessing for the heavy cost 
 of opening these waters, all act as a drag. 
 
 It is not within the purpose of this pamphlet 
 to consider the legal aspect of the difficulty. 
 But on the supposition that an existing obstacle 
 was removed, and miles of new spawning ground 
 opened up, the probable effect would be that the 
 old fishery district, as a whole, would benefit out 
 of all proportion to, the rod fishing created above 
 the obstacle, and the owner of the fishery im- 
 mediately below the obstacle might be presently 
 injured ; and probably, after a few years, sub- 
 stantially benefited by the increased number of 
 fish in his water, due to the produce spawned in 
 the new water returning for a like purpose. 
 
 Until one corporate body in each district has sole 
 power over the net-fishing so that one or more 
 
On Stocking. 25 
 
 tacksmen fish nets in saltwater, and only as sett 1 
 by the said corporate body, net and cruive fishing 
 in fresh water being abolished, and rod fishing 
 for salmon vested in the said body under such 
 limitations as will prevent any gross interference 
 with either private or public rights there is 
 little hope of any rapid improvement of salmon 
 fisheries by scientific fish-culture. 
 
 Each district can only produce a certain gross 
 weight of fish, and this can be more cheaply and 
 quite as certainly captured from half a dozen 
 stations as from a hundred. The total number of 
 fish caught depends on the gross produce of the 
 rivers in the district. The multiplication of fishing 
 stations is merely a needless multiplication of the 
 expense not to increase the total catch, but to 
 decrease the value of rights already existing, and 
 in this matter of late years on the Scottish coast 
 the Crown has not been blameless. To those who 
 know the cost of wear and tear of sea nets, the 
 suggestion that the profits of the Scotch salmon 
 fisheries would be more than doubled under such 
 management will not appear unreasonable, and the 
 equalisation of the assessment that would then be 
 practical would enable fish-culturists to double or 
 treble the total yield of salmon in the district, 
 this yield being controlled by the available area 
 of the feeding ground for salmon fry ground of 
 
 1 This term refers to the conditions of the lease. 
 
26 On Stocking. 
 
 which fish-culturists, with the assistance of arti- 
 ficial redds, would take the fullest advantage. 
 
 On the production of fry in the hatchery, I 
 cannot do better than quote from my History of 
 Howietoun, Part I., p. 57, line 13 : 
 
 'The hatching-boxes are stripped of their fittings, 
 thoroughly cleaned, and the safety-screens fixed 13 inches 
 above the outlet. If the ova is on the point of hatching it 
 is then laid down on the wood. It is often convenient to 
 prepare the boxes a few days before the eggs are due to 
 hatch ; and since, if the eggs remained many hours in the 
 comparatively still water at the bottom, some of the embryos 
 would be drowned, a small piece of tile is laid in the box, 
 and a couple of grilles balanced on it until the hatch com- 
 mences, when the tile is taken out, and the grilles reversed 
 and removed. With 3 inches of water in the hatching-boxes 
 there is no danger of the alevins becoming suffocated a very 
 common source of loss in badly constructed trays. 
 
 'A CO-OPERATIVE BREATHING SOCIETY. Shortly after 
 hatching the alevins congregate together in dense masses 
 in the corners and against the sides of the hatching-boxes. 
 If the water over these masses be slightly discoloured so as to 
 render visible the paths of the currents, small whirlpools will 
 be noticed descending over the apex of each mass, while from 
 the base the water radiates a thin swiftly-moving cloud. 
 
 ' On closer inspection it will be noticed the alevins are 
 lying with their heads approximately towards the apex, and 
 their paired pectoral fins working with remarkable rapidity ; 
 thus, instead of those lowest in the mass being in danger of 
 suffocation, they really receive the strongest water currents. The 
 mass is, in fact, a gigantic co-operative breathing association. 
 
 * Very different is the fate of the unfortunate who finds a 
 refuge beneath the sheet of glass so frequently used in the 
 early days of trout-hatching to preserve the eggs from fungus. 
 In a very few hours a pale lifeless form marks the grave of 
 the suicide. Charred wood has abolished the necessity for 
 
On Stocking. 27 
 
 linings of any sort, but the general public still delight in 
 providing all sorts of death-traps, under the name of shelters. 
 
 ( After the fry have herded together for a few weeks, more 
 or less, according to the temperature of the water, they are 
 seized with a roaming and inquisitive spirit. At this stage 
 the use of flannel in fixing the safety-screen becomes 
 apparent. But it must be new flannel ; old sodden stuff is 
 certainly water-tight, but still the fry manage to burrow be- 
 neath it, and, although they cannot pass through, manage to 
 suffocate themselves in considerable numbers. New flannel 
 is seldom water-tight, but this is of no consequence. Whether 
 the fine hairs annoy them, or whether inherited instinct 
 teaches them to dislike the manufactured product of the 
 animal whose periodic washings have so frequently nauseated 
 their ancestors, I know not ; but it is nevertheless a fact that 
 the alevins will test every joint in the box, but leave the 
 flannel-protected joints of the safety-screen alone. 
 
 ' The only attention newly hatched alevins require is as to 
 the strength of the current passing through the safety-screen. 
 If the water is kept shallow, and the current equivalent to two 
 gallons per minute through the ordinary Howietoun hatching- 
 box, there is some danger, during the first few hours of the 
 hatch, of so many of the holes of the perforated zinc of the 
 safety-screen becoming clogged with cast-off shells as to make 
 the current sufficiently strong through the remainder to catch 
 and hold any unfortunate alevin passing. It is not safe to 
 heighten the water in the hatching-box by placing flannel on 
 the outlet screen before nine-tenths of the eggs are hatched, 
 or the decreased current will cause partial suffocation of the 
 embryos. And even when one-tenth of the eggs are left, 
 they should be well separated with a feather before the water 
 is deepened. If alevins get against the safety-screen, the 
 pressure of the water gradually forces the yolk-sac, which is 
 very elastic, through one of the perforations of the zinc. If 
 No. 9 size is used, little harm accrues, as a strong alevin, so 
 soon as he feels the process commence, can free himself by 
 his struggles ; and he takes care in future to avoid the screen- 
 
28 On Stocking. 
 
 But with a smaller size matters are very different. The least 
 portion of the yolk-sac slipping through which it does the 
 more easily, as the smaller the number of zinc the stronger the 
 current bulges out, and keys the fish on the reverse side of 
 the safety-screen in such a manner that escape is impossible. 
 
 ' At Howietoun the eggs are laid down to hatch between 
 nine and ten in the morning, and unless the day is very cold, 
 the hatch is completed by three in the afternoon, when the 
 shells are skimmed off and the water in the box heightened. 
 This is tedious work, and we do not care to hatch more than 
 a quarter of a million in one day, although it is occasionally 
 necessary to lay down a much larger number. After the shells 
 are skimmed off and the water heightened in the boxes, the 
 attention required is reduced to a minimum. As the fish 
 get stronger the current is increased, the regulating tap being 
 moved once a week through a space equivalent to one quart 
 per minute per box. Hardly any alevins die except in 
 experimental lots. The boxes themselves never require 
 cleaning; the alevins are their own housemaids. They are 
 constantly scouring over the bottom of the box, and keep the 
 charred wood polished like a piece of dark mahogany. The 
 current carries the dirt through the safety-screen, and it 
 settles in the space of 13 inches between that and the outlet. 
 The rough of this dirt is removed with a syphon every 
 morning. Once a week the cork in the settling-tank is drawn, 
 and the bottom of the box thoroughly cleaned with a brush. 
 
 ' The importance of exactly balancing the number of alevins 
 to the box, and adjusting the proportions of the hatching- 
 box to the current, are apparent. There is little danger of 
 having too many alevins in a box, as the number put in is 
 determined by the number of feeding-fry that can be properly 
 reared ; but if too few alevins are placed in the box, or if 
 they have been improperly incubated and have not sufficient 
 vitality, they will neither have strength nor activity to polish 
 the bottom ; and as with due deference to the opinions of 
 some perfect cleanliness at this stage is absolutely essential 
 to their future success in life, if they do not do their own 
 
On Slocking. 29 
 
 housemaids' work it must be done for them at great trouble 
 and expense. Up to this stage the daily work in the hatch- 
 ing-house is much the same for eggs and alevins. It is not 
 advisable to begin too early in dark mornings ; eight o'clock 
 is quite soon enough to unlock the door. The Manager 
 should always enter the house first, check the thermometers, 
 and notice the overflows of the regulating-tanks. The 
 girls then look over the hatching-boxes, pick out the opaque 
 ova, and note the numbers on the printed form. The 
 Manager gives the head attendant a list of the boxes from 
 which all unimpregnated eggs are to be picked, for sale or 
 before laying down to hatch. If it is a bright morning he 
 sees that the swung shutters are tightly closed on the south 
 side of the house. Direct sunlight is not only injurious to 
 the embryos, but is apt to induce a cryptogamic growth on 
 the shells of the eggs. The particular fungus I have not 
 determined, its principal characteristic being the length and 
 delicacy of its filaments. 
 
 ' When any eggs are near hatching, boxes which have been 
 already emptied, for sale or otherwise, are prepared ; if not, 
 the Manager is free to go to the ponds. Should the follow- 
 ing day be one on which ova are despatched, he returns in 
 the afternoon to throw the eggs on to the frames; but on 
 other days he merely looks round in the evening to receive 
 the schedule of the dead ova picked out, and to see generally 
 that all is right. When the alevins are hatched, he has to 
 attend to the depth of water in each box, which is increased 
 by raising the flannel on the outlet screen, and to the weekly 
 increase of the supply when the water is raised. He has also 
 to see that a sufficient number of ova packing-boxes are 
 prepared, with sawdust carefully filled between the inner 
 and outer cases. In practice, it is found necessary to have 
 at least twelve ordinary egg-packing boxes and six foreign 
 always ready in the box-room. He also requires to take 
 stock of the quantity of swan's-down squares, and to check the 
 amount of sphagnum moss in the cellar, where it keeps best. 
 
 ' It must always be remembered that, in the case of a heavy 
 
30 On Stocking. 
 
 snow, it is impossible to get good moss sometimes for weeks 
 together. If the stock runs short at these times, marshy 
 places below springs are generally open, but the sphagnum is 
 rank, soft, and the lower portion frequently bleached, and 
 neither suitable for felting nor capable of living over a long 
 sea voyage. 
 
 * The Manager inspects the grilles removed the day previous, 
 to see if they are in good condition and have been properly 
 cleansed, after which he superintends their being placed on the 
 rafters of a shed, where they remain dry and safe all summer. 
 
 ' When the fry begin to feed, the hatchery demands much 
 more of the Manager's time. He requires to check the food 
 left by the butcher, test the paste prepared for feeding the fry, 
 and to specify the exact quantity of food each box requires. 
 
 ' FEEDING THE FRY. The best and most economical food 
 for trout fry costs about Is. 4d. per lb., and, strange though 
 it may appear, it is much cheaper than liver at Id. per lb., 
 that is to say, one pound of this paste goes far further, and 
 produces much better results, than sixteen pounds of liver, 
 because it is more nourishing, and there is no waste. The 
 food is prepared by weighing several pounds of fillet of beef, 
 not beef-steak, which is too stringy, nor a piece off the 
 surloin, which is generally too fat. Fillet of horse is equally 
 suitable with fillet of beef, and surloin of horse, being 
 generally very lean, is nearly as good. But as no establish- 
 ment kills anything like a sufficient number of horses to 
 supply the fry with the tit-bits, the butcher must necessarily 
 be the chief purveyor. Mutton is not suitable. All the fat 
 being carefully scraped off, and the meat being weighed, it is 
 pounded in a large marble mortar, and passed through a 
 coarse sieve. The yolks of hard-boiled eggs are then added, 
 nine eggs being allowed to each pound of meat. The eggs 
 should be several days old, as, if new-laid, it is impossible to 
 boil the yolk until it is mealy. This can be easily arranged 
 by buying foreign eggs from a wholesale dealer by the box, 
 which runs from 120 to 150 dozen, and at Howietoun 
 
On Stocking. 31 
 
 generally lasts about ten days. When the yolks of egg and 
 and meat have been thoroughly mixed in the mortar, they 
 are passed through a fine wire sieve and kneaded into a stiff 
 paste. This is rolled into the shape of a thick sausage, and 
 cut and rolled into large pills, each sufficient to give one 
 meal to five boxes. Theoretically, the weight of each pill 
 should be checked, but in practice it is found that the eye 
 is a sufficient guide. When the food is all prepared, it is 
 taken into the hatching-house, and one pill placed on the 
 edge of the fifth box in each row. One of the girls then 
 goes round with a feeding-spoon, and, beginning at the 
 bottom box, presses the food through the perforated zinc of 
 the feeding-spoon, which reduces it into fine vermicelli. 
 When the threads are about two inches long, they are shaken 
 off into the water, and the current keeps them always in 
 motion. The fry, having their attention attracted, seize on 
 the moving filaments, and drag them all over the box, causing 
 the greatest excitement, so that the fry eat quite as much 
 out of jealousy as from hunger. I can compare it to nothing 
 else than a pack of highly-bred hounds breaking up a fox. 
 If the meat has been too fat, the filaments adhere, and lie in 
 the bottom untouched. If, on the other hand, too little egg 
 has been used, they break up into a thin soup, which very 
 soon fouls the box. But when properly prepared, and the 
 fry not over-fed, there is not one particle of waste. 
 
 ' The feeding-spoon is made out of elm by boring a large 
 hole out of a 1-inch plank, and making a saw-drift through 
 which to pass the perforated zinc. The hole is tightened up 
 with a couple of brass screws. 
 
 1 Nos. 8 and 9 zinc are the proper sizes. If the holes are 
 smaller it is impossible to pass the prepared food through, 
 and if larger, the filaments are too thick to be easily eaten by 
 the fry, and get broken up. Should it be imperative to feed 
 with liver, sheep's is better than bullock's as it breaks up 
 through the zinc into much larger particles, and, though more 
 costly to buy, there being much less waste, is less expensive. 
 Great care must be taken not to over-feed the fry on the pre- 
 pared food, or they will stretch their stomachs to the size of 
 
On Stocking 
 
 the original yolk-sac, a condition which is generally followed 
 by a suffusion of blood near the anus, and death. 
 
 ' After a fortnight's feeding on the prepared food, finely 
 ground horse-flesh is substituted. This is prepared by select- 
 ing the mash from the large chopping-machine with which 
 the food of the older trout is prepared, pounding it in the 
 mortar, and passing it through a very fine wire sieve. It is 
 then fed out through No. 9 perforated zinc rolled round a 
 circular base. This utensil we call the short feeding spoon. 
 It is found very useful, and obviates any danger of choking, 
 as all particles too large for the fry to swallow are retained 
 in the cylinder, and emptied out into a pail provided for the 
 purpose, to be mixed with the food of the yearling trout. 
 
 * Many ingenious fry-feeding machines have been designed, 
 but as this part of fish-culture demands constant attendance, 
 and can only be successfully undertaken where the whole 
 time of at least one person can be devoted to the trout, I 
 think it unnecessary to refer to them here. The best and 
 simplest is that used at Howietoun in the experimental tanks 
 Nos. 1, 2, 3, and 4. 
 
 ' Amateur fish-culturists should, as a general rule, turn out 
 their fry ten days before the yolk-sac is absorbed. It is a 
 very common error to suppose fry will not feed until the 
 absorption of the sac. Where they are deficient of vitality 
 this may be so, but when the produce of properly selected 
 breeders, and when the eggs have been so incubated as to 
 induce great vitality in the embryos, and where the alevins 
 had suitable depth of water and sufficient current, they come 
 on the feed before the total absorption of the sac. Nature 
 has, in fact, provided them with a large reserve of food, and, 
 if vigorous, the hinder portion of the sac becomes separated 
 by constriction, and drops off under ordinary circumstances, 
 and it is only where there is an absence of vitality that the 
 sac is totally absorbed. 
 
 1 The above does not apply to fontinalis, nor to the ova of 
 young trout, or of grilse, and even with the largest salmon 
 if hatched in water of a falling temperature, whereby the 
 period of alevinage is much prolonged, when the whole nutri- 
 
On Stocking. 33 
 
 ment contained in the sac becomes necessary to the life of 
 the fish. 
 
 ' DESPATCHING FRY. In the early days of trout culture 
 fry formed the principal sales ; few cared for the trouble of 
 hatching the ova. The carriage of yearlings was far too 
 expensive ; clearing-house rates were unknown ; proper pre- 
 paration not understood ; nothing better than a carboy had 
 been thought of for their transport. The water in which 
 they were conveyed required to be frequently changed ; air 
 required to be supplied either by splashing the water or by 
 bellows, and an attendant's constant anxiety frequently 
 supplied an illustration of the proverb, "Care killed the 
 cat," especially if he solaced himself with a pipe of tobacco 
 during an extra long spell at the bellows. In those days fry 
 were very costly, and, as a natural sequence, they were care- 
 fully counted before despatch. Now, if there is one thing 
 more fatal to fry than another, it is catching and counting 
 them; the least touch removes the mucous, and fungus 
 follows. This was very early discovered at Howietoun, and 
 many methods were tried to mitigate the evil. They were 
 caught up on perforated zinc, counted, and washed off into a 
 pail ; they were skimmed up with a light muslin skimmer 
 mounted on fine wire ; they were spooned up with a soup- 
 spoon; they were shovelled up in a miniature dust-pan 
 (used for sanding birds' cages); they were poured into milk- 
 plates, and counted as they passed over the spout into a pail ; 
 but none of these methods were satisfactory. The miniature 
 dust-pan was, however, far the best and quickest of the lot. 
 
 ' After much consideration, and seeing that two grilles of 
 ova were laid down to hatch in each box which was always 
 7000 eggs, and frequently more than 8000, # was decided 
 to sell fry by the box, guaranteed to be not less than 5000. 
 This left a margin of about 50 per cent., and the Fishery had 
 the satisfaction of knowing that the fry despatched were un- 
 injured ; and although the price might appear high in com- 
 parison with that of ova, the results obtained were so satis- 
 factory that the sale of fry has steadily increased every year. 
 
 c 
 
34 On Stocking. 
 
 * PREPARING FRY. The preparation of fry is a very difficult 
 matter. It does not do to starve them, or they lose vitality, 
 and cannot find their own food when turned adrift in strange 
 waters. On the other hand^ if they are fully fed, they travel 
 uncommonly badly. We have found them travel best if fed 
 on sheep's liver for a week before they start ; but it makes a 
 foul mess on the bottom of the box, which must be carefully 
 cleaned before pouring the fry out, as, if the water in which 
 they are transported is the least dirty, a large proportion of 
 them will perish. If they are fed on the prepared food up 
 to the day of starting, their stomachs are too distended, and 
 inflammation would be the result. If fed on pounded horse- 
 flesh, the matter they deposit is too gross, and the water 
 becomes fouled. 
 
 ' Fry stand cold badly, and travel best in the daytime. 
 They may be lightly fed over-night before starting, but not 
 in the morning. 
 
 'FRY TRAVELLING TANKS. Fry will not stand much 
 knocking about, and if the yearling tanks are used to trans- 
 port them they must be filled until the water stands above 
 the point of the perforated zinc cone, the wave rising and 
 falling though the zinc is cushioned, and the motion at the 
 bottom of the tank greatly modified. 
 
 ' The bottom of a tank used for transporting fry should be 
 stiffened by cross-pieces soldered underneath, as, if it saggs 
 at all, the fry soon get fatigued, possibly because the least 
 spring from the bottom frightens them, and they exhaust their 
 strength by frequent and aimless sallies through the water. 
 
 * The old tank used to carry the fry from Middlethird to 
 Loch Leven in 1875 answers the purpose well, but the area 
 of the bottom is so small only a few thousand fry can be 
 contained in it. It has, however, the advantage of being 
 light, and can be placed on a dog-cart or the box of a four- 
 wheeled cab, and is perhaps the handiest shape for amateur 
 work. Pieces of wood carrying iron lugs have been bolted 
 on to the side, so that it can be carried between two sticks- 
 
On S toe kino-. 35 
 
 Ventilation is provided by little cylinders of perforated zinc 
 soldered round an aperture in the lid and guarded by its 
 handle. This in practice has been found sufficient. 
 
 ' Carboys are used by some pisciculturists, and, when well 
 filled with water, there is no jar ; they keep a very equitable 
 temperature, the thick glass being a bad conductor, besides 
 which they are generally packed in a basket. The only 
 objection I have to them is their weight, and the space they 
 occupy in proportion to the number conveyed. Fry appear to 
 travel by sea fairly well in carboys ; while, in conical 
 travelling tanks, they appear to suffer from the motion of the 
 steamer. During the Edinburgh Exhibition of 1881, some 
 thousand fry of Coregoni arrived in good condition from 
 Russia. They were carried in a modified form of carboy 
 packed in a square box lined with felt, air being admitted by 
 a tube passing through a cork. 
 
 ' Conical tanks have one advantage in warm weather ; if a 
 jacket of coarse sacking be laced tightly over the tank, and 
 the lid arranged so as to admit sufficient water to escape to 
 keep it damp, the evaporation will cool the tank so that the 
 temperature seldom rises above 45. The best temperature 
 for travelling fry is, I think, above 40, and certainly below 
 50. I do not think it ever advisable to reduce the tempera- 
 ture of the water in the travelling tank below that at which 
 the fry are being reared, which is usually below 50.' 
 
 FRY : ITS APPROPRIATE USES. The cases in 
 which fry are preferred to Ova sown in redds are 
 few ; but in the case of district Boards where the 
 heavy cost of yearling ponds makes it impossible as 
 yet to rear the fry, the best course is to make redds 
 in the upper and less accessible waters for one half 
 the eggs incubated, and to feed the remaining 
 half as fry until the beginning of the fourth 
 
36 On Stocking: 
 
 month after hatching, and then turn them out 
 into the most accessible of the suitable fry- rearing 
 grounds of the district. A second and important 
 use of fry is the stocking new reservoirs where the 
 feeding streams are practicable. This has been 
 done most successfully in the case of Lake Vyrnwy, 
 the new reservoir of the Liverpool Corporation, to 
 which 300,000 8. Levenensis fry were successfully 
 sent from Howietoun in 1889, and which, being 
 almost entirely new ground, yielded this last 
 season, 1891, the most gratifying results. A thir.d 
 use of fry and by no means an unprofitable one 
 for those who have suitable yearling ponds, but 
 without the command of good hatching water, is 
 the transplantation of fry, to grow to yearlings or 
 two-year-olds for sale purposes. This we find a very 
 satisfactory market, since once established it con- 
 stitutes practically a clientele of annual customers. 
 Fry are also much esteemed by angling associa- 
 tions and tenants of fishing who wish to improve 
 their sport, but do not care to construct permanent 
 fixtures. Although in the above two cases, year- 
 lings would generally but not always be more 
 satisfactory. To use fry advisedly, it is wise to 
 consult some practical fish-culturist. 
 
 THE COST OF FRY. The great cost of fry is due 
 to the space they require, and the loss due to 
 netting them when required for transplantation. 
 At Howietoun experience is in favour of fry never 
 
On Stocking. 37 
 
 being placed in any trough or box larger than can 
 be easily lifted by two men, and the fry poured 
 out into the pitchers or carrying tanks. In 
 practice, this entails a cost for house room so to 
 speak double of that for incubation of the eggs, 
 since, as compared with the number of eggs, only 
 half the number of fry can be safely and advanta- 
 geously fed in any given box. 
 
 Thus the produce of a gallon of Ova costs 2, 4s. 
 for house rent, as compared with 1, 2s. per gallon 
 of Ova for the period of incubation thereof. Fry 
 further cost four times as much for labour, and 
 consume about 1 per gallon of food. 
 
 The ledger account stands thus : For a house 
 capable of incubating 80 gallons of Ova and rearing 
 the produce of 40 gallons as fry for three month 
 after hatching, (See page 17). 
 
 Interest on ^3000 at 4 per cent., . . . .120 
 
 Depreciation and renewal calculated on 80 gallons 
 
 of Ova as 14s. per gallon (see page 18), . . 56 
 
 .176 
 Of which one-half is credited to use for Ova leaving 
 
 to debit of Fry, . . . V ...."'. . .88 
 Add Wages at 80s. for 15 weeks, . ; 60 
 
 Cost of rent and wages for rearing the produce 
 of 40 gallons of Ova for three months after 
 hatching, . . .148 
 
 or, divided by 40 gallons, 3, 14s. per gallon 
 of Ova this, added to the 1, 9s. 6d., makes 
 
38 On Stocking. 
 
 5, 3s. 6d. for the produce of one gallon of Ova 
 reared- to three-month- old fry for rent and wages 
 alone. Food for this quantity, as extracted from 
 Howietoun ledger, cost 42, or 1, Is. per gallon. 
 This, added to the lowest cost of production of 
 Ova (page 22), viz., 6 per gallon, being the total 
 cost of fry three-rnonth-old and thoroughly fit to 
 transplant, to 12, 4s. 6d., or, at the ordinary 
 cost of production of Ova unfertilised (viz., 9 
 per gallon) to 15, 4s. 6d. 
 
 A gallon of Ova may be supposed to average 
 28,000 three-month-old fry, and it is sold in four 
 boxes of 5000 each nominal, delivered carriage 
 paid at 5 per box, that is, 20 per gallon Ova 
 used to produce to fry. And the cost of delivery 
 varies between 4, 10s. and 6, for any distance 
 beyond local traffic rates. The weight of the water 
 required for transplantation closely approaches 
 one ton. 
 
 Three-month-old fry have been so successful 
 when properly used, and are rising so rapidly in 
 the estimation of the public, that the price will 
 probably rise slightly in the future, as at present the 
 margin is dangerously small. Roughly, the cost 
 of the production of three -month- old fry may be 
 stated at between 70 and 80 per hundred 
 thousand nominal, and one-fifth less per hundred 
 thousand actual count. 
 
On S toe king. 39 
 
 YEARLINGS. 
 
 Their Production, Appropriate Employment, 
 and Cost. 
 
 THE PRODUCTION OF YEARLINGS from fry is 
 a very simple matter. The fry are merely placed 
 in suitable ponds and fed sparingly but continu- 
 ously for all daylight hours from May until 
 August. The food is cheap, consisting at first 
 of raw liver, and afterwards of finely chopped 
 horseflesh. The ponds must be suitably con- 
 structed (see page 62) and the earth renewed 
 each season. Gulls and herons require shooting 
 and trapping, or a dog may be trained to herd the 
 ponds and scare off the water-fowl. One collie at 
 Howietoun is unceasing in this watch, but in spite 
 of dogs, traps, and guns, the gulls do take a very 
 serious toll of the fry when first placed in the 
 yearling ponds. One hundred thousand (nominal) 
 three-rnonth-old fry require four ponds, each 100 
 feet long by 22 wide at top by 5 feet 6 in depth, 
 and should make from 30,000 to 40,000 good 
 saleable yearlings and a few thousand undersized 
 fish. The ponds must be dried for one month, 
 and must stand full of water for at least three 
 weeks before stocking, five weeks is better, so that 
 the water becomes charged with animal life. The 
 most difficult time for the fish-culturist is the 
 
40 On Stocking. 
 
 few days immediately following the plantation of 
 three-month-old fry. Numbers weaken through 
 starvation before they know the feeding spoons, 
 but when there is ten days supply of natural 
 food in the pond, no fry weaken through starva- 
 tion, and five boxes of fry will produce the same 
 number of yearlings that, under less favourable 
 circumstances, six boxes would produce. 
 
 APPROPRIATE EMPLOYMENT OF YEARLINGS. 
 Yearlings fit all uses, they travel better than any 
 other size. They bear out Mr. Guy's description 
 of them in the Howietoun Fishery Price List :- 
 
 ' Yearlings are, par excellence, the size for general purposes. 
 They are strong enough to find their own food, thus avoiding 
 the principal cause of mortality among fry, namely, starva- 
 tion ; they are easily carried, and stand the journey well ; 
 they accomodate themselves with the greatest facility to new 
 water ; and they thrive so fast in ponds that they will be 
 found a very profitable investment.' 
 
 As a rule, yearlings are better than two-year- 
 olds for rivers ; of course there are rivers 1 where 
 two-year-olds may be preferred, but all two- 
 year-olds are grown in comparatively still water. 
 It would not pay to make a two-year-old pond on 
 the principal of a long narrow ditch, and this is 
 precisely the principal on which the most successful 
 yearling ponds have been constructed. 
 
 Yearling ponds may be varied in shape to suit 
 
 1 E.g., the Thames below Henley. 
 
On Stocking. 41 
 
 circumstances, and in many cases with excellent 
 results, vide Mr. Andrews' successful ponds near 
 Guildford, where the adaptation of old water-cress 
 beds has proved most remunerative ; but under 
 ordinary conditions the ditch form gives the 
 largest return on the outlay, and (with the full 
 supply of water usually given to this class of 
 yearling ponds) most nearly resembles conditions 
 which abound in rivers and streams in all parts of 
 the country. Yearlings from these ponds, there- 
 fore, when transplanted to rivers, find conditions 
 not greatly at variance to those under which they 
 have been reared. With two-year-olds it is vastly 
 different, they have been reared in larger ponds, 
 where they enjoyed a wider range, and even if 
 the supply of water to their pond was propor- 
 tional to the supply usually allowed to yearling 
 ponds, yet the greater depth and breadth of 
 their pond so altered the amount of current as to 
 habituate the fish to comparatively still water. 
 Yearlings, therefore, have an advantage over two- 
 year-olds when transplanted to small streams or 
 rapid rivers. 
 
 Yearlings have a further advantage over two- 
 year- o]ds at present rates for carriage, as, 
 roughly speaking, 2 tons 10 cwt. are required 
 to safely transport 1000 two-year-olds for twelve 
 hours, while 15 cwt. is amply sufficient for the 
 same number of yearlings on a similar journey. 
 
42 On Stocking. 
 
 Yearlings can find their own food in any new 
 water if it is not over-stocked. Practically they 
 may be appropriately used in every case where 
 they are not exposed to predatory fish or birds ; 
 and even then it becomes a question involving a 
 delicate calculation, whether or not it is cheaper 
 to increase the number of yearlings transplanted, 
 so as to discount the loss, or to incur the expense 
 of two-year-olds. Generally, yearlings should be 
 used wherever the water is unsuited to fry. 
 
 There are many hill lochs which can be stocked 
 by yearlings, and by nothing else, where there is 
 little or no feeding stream, or where the feeding 
 stream is too rapid or too rocky to suit fry, and 
 where the difficulty of access forbids the tanks 
 necessary to carry two-year-olds being brought 
 within a reasonable distance of the water. 
 
 There are many lowland ponds which can be 
 stocked with yearlings more satisfactorily and 
 more economically than by any other description 
 of fish the number of yearlings being propor- 
 tioned to the capacity of the water, and the risks 
 inevitable from birds and large fish. 
 
 There are many rivers where two-year-olds 
 would wander to stiller water, and where fry 
 would have little chance of survival but where 
 yearlings would give for many years after the 
 stocking a good account of themselves. 
 
 And there are many ponds all over the country 
 
On Stocking. 43 
 
 which, if stocked annually with yearlings to be 
 sold as two-years-olds the following winter, would 
 yield a very handsome return for the cost and 
 trouble : only these ponds would require to be 
 annually emptied, as a few of the previous years' 
 stocking would make short work of the new-comers. 
 
 THE COST OF YEARLINGS. Yearlings, when 
 grown in artificial ponds, are so under control that 
 the cost is fairly stable, taking one year with 
 another ; and is composed of the following items : 
 Cost of fry ; rent of pond, including water supply 
 and renewals ; cost of food and attendance, in- 
 cluding the preparation of food. There are other 
 items before they can be despatched, such as 
 office correspondence, cartage to station, netting 
 and cost of preparation for without some pre- 
 paration yearlings travel indifferently. 
 
 The first of these items, viz., cost of fry. One 
 gallon of Ova incubated and reared into four 
 boxes of three-month-old fry costs 15, 4s. 6d. 
 (see page 38), taking the ordinary cost of produc- 
 tion of Ova at 9 per gallon. A little over 30 
 gallons of Ova incubated and reared to three- 
 month-old fry was used last season at Howietoun, 
 or about 120 boxes of fry; the value of which, 
 on the above basis, was 450, 15s. The actual 
 cost of food is not easily ascertained from the 
 books, as it was not kept separate from that of 
 
44 On Stocking. 
 
 the two-year-olds, but it was not less than .80 
 for the nine months. The attendance was prac- 
 tically equal to the whole time, one man and one 
 girl for the same time, say 78. The cost of 
 rent, labour in renewals, wear and tear, cultivating 
 the ponds by drying and re-earthing the bottoms 
 and sides, must also be to some extent a matter 
 of guess-work, but if taken at 1 per cent, on the 
 structural cost of the 20 ponds, which was between 
 2000 and 3000, a sum of 250 per annum 
 is obtained. Personally, I think, 10 per cent. 
 is too little to allow for this item in most cases ; 
 but the ponds at Howietoun are very well con- 
 structed, and the annual renewing of the earth- 
 surface of the bottoms and sides, for purposes of 
 sanitation, is the principal item of expense. In the 
 case of such ponds as Fishery Boards are likely to 
 construct, from 1 2 per cent, to 1 5 per cent, should 
 be estimated for, especially since, if the first cost 
 is reduced, not only are more repairs entailed 
 annually, but the capital sum on which the 
 estimate is based is lower, thus necessitating a 
 higher percentage. The cost of 30 gallons of 
 Ova grown into yearlings will thus be : 
 
 Cost of three-month-old fry, . . . .450 15 
 
 Rent, repairs and renewals, etc, . . . 250 
 
 Cost of food, , 80 
 
 Attendance, . ' . . . . . 78 
 
 Cost of 30 gallons of Ova = 120 boxes of fry 
 
 = from 140,000 to 200, 000 yearlings, . 85815 
 
On Stocking. 45 
 
 or, a gallon of Ova may be expected to produce 
 from 4,700 to 6,700 yearlings at a cost of 28, 
 5s. Id., or from 4, 5s. lO^d. to 6, 2s. 8^d. per 
 thousand. The latter price is nearer their average 
 of good work than the former, as 200,000 year- 
 lings could not be reared, in the ponds estimated 
 on, without loss of average size ; and, in any case, 
 there is always at least 10 per cent, of small 
 yearlings which are unsaleable. 
 
 Writing from a District Fishery Board point 
 of view, it would be fair to say that allowing 
 no sum for management, risk, or profit, and 
 working on this large scale, yearling trout may 
 reasonably be expected to be produced at 6 per 
 thousand, counting all fish whether sizeable or 
 not. From a fish-culturist point of view, office 
 expenses, risks, netting, preparation, despatch 
 and cartage to station, and wear and tear of 
 travelling tanks no small item in itself must be 
 added, and the difference between that and the 
 price is the profit on each gallon of Ova in- 
 cubated and reared to yearlings. In practice, 
 these items bring up the average cost to a little 
 over 9 per thousand, free on rail. The cost ot 
 preparation alone at Howietoun, that is, 4 per cent, 
 interest on the cost of the two substantial despatch- 
 ing houses, and the renewals of the wooden tanks 
 and machines employed to save handling the fish, 
 amounts to 13s. 4d. per thousand yearlings, and 
 
46 On Stocking. 
 
 1, 13s. 4d. per thousand two year-olds but 
 the saving in cost of railway charges for carriage 
 is in each instance much greater. In conclusion, 
 we are of opinion that, while Fishery Boards 
 working on this large scale may, under favourable 
 circumstances, raise yearlings at 6 per thousand 
 all told, large and small, it would not pay them 
 to place their surplus stock on the market below 
 10 per thousand, and if they only rear 50,000 
 or 60,000 yearlings annually, it is open to doubt 
 whether these yearlings will not cost close on 10 
 per thousand in the ponds before handling at all. 
 In the above calculations all profit in any of the 
 stages has been neglected. If in the table (page 
 44) we substitute the price of 30 gallons of Ova 
 grown into three-month-old fry for the bare cal- 
 culation cost. The table will stand thus : 
 
 The equivalent of 30 gallons of Ova, viz., 120 
 
 boxes of fry at 5 per box, .... 600 
 
 Kent, repairs and renewals, .... 250 
 
 Cost of food, 80 
 
 Attendance, 78 
 
 Cost of equivalent of 30 gallons of Ova in year- 
 lings, say from 140,000 to 200,000, . , 1008 
 
 or 33, 12s. per gallon, or from 5, Os. lOd. to 
 7, 4s. per thousand. This calculation is made 
 for the convenience of Boards and Associations, 
 who prefer to purchase their fry instead of incurr- 
 ing the expense of a large hatching house. And 
 
On Stocking. 47 
 
 the fact cannot be too frequently impressed that 
 first-class incubation demands such an equality 
 of temperature as can only be secured in this 
 climate by substantial masonry. 
 
 TWO-YEAR-OLDS. 
 
 Their Production, Appropriate Employment, 
 and Cost. 
 
 THE PRODUCTION OF Two- YEAR- OLDS from 
 yearlings consists in the careful sizing of the 
 yearlings, and the removal of all above and below 
 a certain standard. Should this be omitted, 
 cannibalism is sure to arise, and, strange as it 
 may appear, there is more risk of cannibalism in 
 permitting a few hundreds of small yearling in 
 the two- year-old ponds than in overlooking a few 
 larger yearlings. The small trout are eaten by 
 those yearlings, who may be supposed to have a 
 larger share of original sin, and when once they 
 commence the practice they rapidly outgrow 
 their companions, and attain a sufficient size to 
 prey on the ordinary stocking of the pond. 
 These cannibals are easily known by sight; not 
 only do they appear shorter and plumper than 
 the others, but (with S. Levenensis, at least) their 
 silvery sides assume a bright golden tint. In 
 
48 On Stocking. 
 
 practice, the secret of growing evenly sized two- 
 year-olds lies in the careful selection and segre- 
 gation of the yearlings. 
 
 The ponds suitable to two-year-olds require to 
 be deeper and wider, but not necessarily longer 
 than those for yearlings. At Howietoun, we 
 prefer a depth of from six to twelve feet. The 
 supply of water is not so material in the case of 
 two-year-olds as it is in the case of yearlings. 
 Yearlings require a current ; two-year-olds require 
 range and the amount of range at this stage has 
 a marked influence on the future shape of the 
 mature trout. Stone says in his Domesticated 
 Trout 1 (a book that should be in the hands of 
 every fish-culturist : 
 
 'If you want to have trout short and deep, and to use an 
 expressive Americanism, " Chunky," grow them in a deep 
 still pond. If you want to have them long and slim, grow 
 them in a shallow, swift current.' (Dom. Trout, p. 276.) 
 
 And again at p. 235 : 
 
 ' Give them range. If you want to grow your trout very 
 large, you must give them range : I say if you want to grow 
 them very large. Eange is not necessary, by any means, to 
 the average growth of trout, for they will grow to a very 
 good size in small places, and it is also generally incompat- 
 ible with trout growing as a business to give them great range ; 
 but if you want to raise the very largest trout, you must give 
 them the very largest range. Trout will not grow above a 
 certain size in confinement. They will stop, or nearly stop 
 
 1 Domesticated Trout : How to Breed and Grow Them, by Living- 
 ston Stone, A.M. Boston : James R. Osgood & Company, 1873. 
 
On Stocking. 49 
 
 growing, when they have reached a certain limit. Range also 
 influences the rate of growth. Large ponds grow trout faster 
 as a rule than small ponds. Put ten trout in a pool three 
 feet square, and ten others in a pond ten rods square, and 
 those in the pond will grow much faster than those in the 
 pool on the same food.' 
 
 Stone of course writes on the American brook 
 trout, S. fontinalis, which is a first cousin of the 
 Highland Chars ; but the above extract is equally 
 applicable to our British trout. Stone goes 
 on to impress the necessity of giving trout plenty 
 of space, and dilates on the difference between 
 range and space ; but in this matter I do not 
 entirely hold with him. Space means the cubic 
 feet of measurement in each pond divided by the 
 number of trout. Now, the real factor is com- 
 posed of surface measurement ; gallons of fresh 
 water or cubic feet of fresh water supplied per 
 minute ; and cubic contents of the pond in feet ; 
 and it is further varied by the capacity for 
 oxygen of the water a capacity which is exceed- 
 ingly variable. 
 
 The real crux is to furnish each fish with a 
 sufficient supply of oxygen. The water may be 
 considered as the medium from which this supply 
 is obtained. Again, the quantity of available 
 oxygen must be proportioned to the gross weight 
 of trout, and not to the number of fish, and again, 
 a slight rise of temperature will double or treble 
 the quantity of available oxygen required. I 
 
50 On Stocking-. 
 
 used the term ' available oxygen/ because more or 
 less of the oxygen in the water is neutralised, or 
 imprisoned by carbonic acid given off by the trout 
 themselves, and otherwise present in the pond. 
 
 So intricate is this question of space per 
 pound of trout live weight, that nothing but 
 practice can determine the proper stocking for 
 two-year-olds in each case ; and there must be 
 sufficient margin left for safety during a thunder- 
 storm on the hottest day of summer. If a pond 
 is so stocked as to just pass through this ordeal 
 without inconvenience, there will be no further 
 risk from over-stocking, as the trout grow larger 
 the weather becomes colder, and less and less 
 oxygen per pound of trout is required. 
 
 In the production of pedigree two-year-olds for 
 future breeders more care is required in selection, 
 and the largest yearlings must be carefully ex- 
 cluded. One season we carefully selected the 
 largest yearlings, and the result was that the two- 
 thirds of the future breeders turned out to be male 
 fish a most undesirable result when the high cost 
 of feeding the breeders on shell-fish is taken into 
 account. Attention to pedigree and space is 
 most important; and the rule for space in this 
 case is place no more fish in the pond than are 
 necessary to consume all the food thrown in, for 
 if a pond is understocked the fish scatter, and 
 much of the food falls to the bottom and fouls 
 
On Stocking. 51 
 
 the water far more than a much larger number of 
 fish would do. 
 
 APPROPRIATE EMPLOYMENT OF Two- YEAR- OLDS 
 AS A MODE OF STOCKING. Two-year-olds are not 
 advisable for stocking the upper portions of rivers ; 
 they will seek deeper water, 110 matter of what 
 breed they may be. Wherever coarse fish, such as 
 perch and dace thrive, two-year-olds may be used 
 with safety, but not above the limit of dace water. 
 
 For all ponds two-year-olds are better than 
 yearlings, inasmuch as, if the feeding is at all 
 plentiful, they will be fit for the rod by the end of 
 the same season in which they were transplanted. 
 
 In lakes and larger pieces of water a sufficient 
 stocking of two-year-olds is often too costly, and 
 yearlings are used instead ; but our experience is 
 that the public is beginning to discover that for 
 ponds, lakes, and reservoirs, two-year-olds, from 
 the speedy sport they afford, are more advan- 
 tageous than any other mode of stocking, and 
 consequently at Howietoun no effort has been 
 spared to provide for their accommodation. 
 
 COST OF TWO-YEAR-OLDS. The production of 
 two-year-olds on a large scale is of too recent 
 development to admit of any accurate estimate 
 of their cost on the same lines as given for Ova, 
 fry, and yearlings. Taking yearlings at 10 per 
 
52 On Stocking. 
 
 thousand, the present price of two-year-olds, viz. : 
 25 per thousand, leaves a larger margin of profit 
 than the price at 10 per thousand of yearlings 
 does ; but the market value of two-year-olds is 
 limited by value of three-year-olds at the fish- 
 mongers, and 25 per thousand leaves a good 
 margin of profit to any one who cares to fatten 
 two-year-olds for the market. With a little skill 
 and attention they may be fattened as yeld 
 trout for the following November, December, and 
 January, the process must not be commenced 
 too early, or the ovaries will start into activity, 
 and, instead of fat half-pound trout, a lot of 
 immature spawners will result. 
 
 The heaviest item in the cost of two-year-olds 
 delivered is the cost of carriage. There is no 
 sense in forwarding trout with too little water to 
 save carriage ; if the trout arrive sick they will 
 partly die, and the remainder will take weeks, or 
 perhaps months, to recover from the bad effects of 
 this journey. If, on the other hand, the two-year- 
 olds have been transplanted with a generous supply 
 of water, they wdll go ahead and thrive from the 
 first or second day after their transplantation. Of 
 course, the weight of water required varies very 
 much according to the temperature of the air. 
 During the journeys in a hard frost almost any 
 liberties may be taken with impunity, but in warm 
 weather the contrary is the case, and the warmer 
 
OH Stocking. 53 
 
 the weather the less ice can be used without injury 
 to the trout, as it is of importance that the sum 
 total of the difference, of the temperatures of the 
 ponds, the water in the carrying tanks, and of 
 the water of their new home, should be as small 
 as possible. 
 
 The average weight of water allowed for two- 
 year-olds is 2 tons 10 cwt. per thousand, and the 
 cost of carriage including return empties is 
 about 6 per ton for any distance over 200 
 miles, or 15 per thousand, making 40 per 
 thousand, delivered at purchaser's risk, or under 
 lOd. per fish. For shorter journeys, or in very 
 cold weather, the cost of carriage is less, in some 
 cases much less. But even at the higher rate 
 good two-year-olds are a most profitable invest- 
 ment. 
 
 THE CONDITIONS UNDER WHICH OVA, FRY, 
 YEARLINGS, AND TWO-YEAR-OLDS, CAN BE MOST 
 PROFITABLY USED. These conditions are practi- 
 cally a repetition of what has been written under 
 appropriate uses of Ova, Fry, Yearlings, and Two- 
 Year-Olds, but it will be convenient to consider 
 them under one head, more especially as there are 
 circumstances under which all four modes of 
 stocking can with advantage be used together ; for 
 instance, Highland lochs, especially those situated 
 not far above the sea level, generally have long 
 
54 On Stocking. 
 
 stretches of sluggish water immediately above the 
 mouths of the principal streams running into 
 them ; these stretches of water have sometimes 
 pike and frequently perch, and are therefore un- 
 suitable for yearlings, but as the feeding is usually 
 more abundant in such places than elsewhere, or 
 than in the loch, they are just the spots to choose 
 for turning in two-year-olds, while higher up the 
 principal burns there is often found that sequence 
 of pool and shallow so suitable for yearlings ; 
 higher up again there are gravelly places where 
 fry can find food and shelter, and many of the 
 smallest burns have clear springs where Ova may 
 be laid down, if on the point of hatching, without 
 any redd or other preparation, and with the cer- 
 tainty of success. With conditions similar to the 
 above, the greatest economy will be obtained by 
 a nice adjustment of numbers of each of the four 
 classes, viz., eggs, fry, yearlings, and two-year-olds, 
 
 REDDS. 
 
 The formation of redds is a very simple matter, 
 nevertheless much skill and local knowledge may 
 be advantageously exercised in the choice of posi- 
 tions. 
 
 A careful survey of the stream or river should 
 first be undertaken, and the amount of suitable 
 shallows for rearing fry carefully noted. The 
 
On Stocking. 55 
 
 best fry-ground are those portions of the stream 
 or river where the bottom varies from coarse 
 sand to small stones, and where small shallow 
 pools and slight eddies are interspersed. 
 
 When the survey is made in winter great local 
 knowledge is necessary to determine the amount 
 of fry-ground available in summer. April and 
 May are the best months to make the survey, as 
 it is in those months the fry leave the redds and 
 are in more need of the protection yielded by 
 good fry- ground than at any subsequent time. 
 
 Having found a stretch of good fry-ground, the 
 next business is to choose a situation, for the 
 redd, a few hundred yards above. If a tiny 
 stream or clean ditch can be found, a little 
 coarse gravel is all that is required, but if the 
 water has to be brought from the main stream, 
 or from a brook or ditch subject to high floods, 
 the redd must be cut some distance back from 
 the water and well above the highest flood, so 
 that even the bottom of the redd is above high 
 flood level. The principles which govern the 
 'construction of a redd are the same as governs 
 the construction of a hatching- box, 'viz., that 
 the stream or current washes every egg and re- 
 moves the carbonic acid exuded in the process of 
 incubation. In a redd the eggs are more spread 
 and a much slighter current is sufficient than 
 that required in a hatching-box. The redd should 
 
56 On Stocking. 
 
 be narrow, not over two feet wide at bottom, and 
 any convenient length ; two square feet of bottom 
 per thousand eggs is the minimum space advisable, 
 and five square feet per thousand eggs the maxi- 
 mum. A redd two feet by twenty feet will hatch 
 out a box of from 15,000 to 20,000 Ova safely, 
 but when practicable it is better to make smaller 
 redds and more of them. 
 
 The depth of water in a redd should be from 
 three to six inches, not less than three or more 
 than six. The sides of a redd are best left as cut 
 out of the soil, and sloped as little as possible so 
 as to shade the redd, which should also be covered 
 with open hurdles or fir branches anything in 
 fact which will freely admit the air and modify 
 the light. Light is one of the worst destroyers 
 of trout-life, especially in the earlier stages. 
 
 The inlet of the redd may be either a four or 
 six inch pipe not larger than six, or too much 
 water may be passed through the redd in time of 
 flood. The inlet should be taken off the stream 
 in a wooden box guarded with perforated zinc, 
 to prevent small trout or sticklebacks entering 
 and feeding on the alevins. The outlet should 
 have a fall arranged to effect the same purpose. 
 Mice are sometimes troublesome, but do not feed 
 in water over four inches. Water-rats, however, 
 must be guarded against, as they are greedy 
 feeders below water. It is not advisable to fence 
 
On Slocking. 57 
 
 the outlet of the redd, as the object is to permit 
 the young fry to find their way into the stream 
 under as nearly the same conditions as if hatched 
 in it as possible, but a loose wall of coarse gravel 
 and small stones forms no impediment to the 
 alevins passing out, and affords some protection. 
 
 The quantity of Ova hatched out in redds proxi- 
 mate to any given fry-ground in the stream or 
 river must be adjusted, not only to the extent 
 of fry-ground and the probable amount of feeding, 
 but a full allowance should be made for the 
 amount of natural fry from the adjacent spawning- 
 beds, and this only local knowledge can estimate. 
 However, the artificially incubated Ova from the 
 redds will usually, but not always, have several 
 weeks start of the natural fry, and be able to 
 hold their own in the struggle for sustenance. 
 
 REDDS will not take the place of stocking by 
 yearlings or by older trout, but in most waters 
 they will form a valuable adjunct to such stocking. 
 
 PONDS. 
 
 The general principles which govern the con- 
 struction of ponds, are : shade, food, control, 
 facility for emptying, and water supply. 
 
 Shade is the first requisite, and may be 
 given by artificial shade ; by position, as proxi- 
 mation to natural shades from trees, banks, 
 
58 On Slocking. 
 
 hedges, etc. ; by construction, viz., by making- 
 steep sides to the pond ; by depth of water ; by 
 water-plants ; and by any combination of the 
 above. 
 
 Food is the next requisite ; without shade trout 
 won't live, without food trout won't grow. Natural 
 
 * o 
 
 food may be produced by planting suitable water- 
 plants, and sowing amongst them gammari and 
 limncea, water-shrimps and water-snails. Artificial 
 feeding requires every portion of the surface of 
 the pond to be within easy throwing distance 
 from the bank, so that all the trout may be fed 
 by scattering food on the water. 
 
 Control is also very important, and means that 
 the trout can be caught and handled whenever 
 necessary, for sizing or other purpose. 
 
 Facility for emptying requires a drain passing 
 below the deepest part of the pond it is not 
 necessary for the first stocking of a pond, but is 
 very desirable before any future stocking, so that 
 the pond may be cleansed and all fish of the 
 former stocking removed. 
 
 Water supply governs the number of trout of 
 a given age the pond will safely carry. Bearing 
 the above principles in mind, it is of little con- 
 sequence how the pond is formed, whether by 
 damming, or banking, or partly or wholly by ex- 
 cavation only, in the case of damming a portion 
 of a stream, the danger from floods must be taken 
 
On Stocking. 59 
 
 into account and an ample bye-wash provided. 
 The inlet of a pond is easily screened against trout 
 ascending a very slight fall over a ledge into 
 shallow water is sufficient ; trout cannot jump out 
 of shallow water as they can out of deep ; but 
 the outlet screen presents more difficulty arid 
 should be large enough to pass all the water in 
 time of flood, and deep enough below the outlet 
 to pass all the water in time of frost. 
 
 The best water-plants for ponds must vary in 
 every locality, generally speaking, watercress-beds 
 in connection with the inlet give excellent results. 
 
 The depth of the pond effects the gross weight of 
 trout the pond can rear more than anything else: 
 with shade, a pond only one foot deep will hold a 
 few small trout, but the largest trout require even 
 with shade, at least six feet of depth of water. 
 
 Ponds sometimes get very milky in the early 
 winter, and as all conditions of water have impor- 
 tant bearings on trout life, I note -the observations 
 here, so that others may consider the question. 
 I suggest as an explanation the probability that 
 the sudden chilling of a thick layer of water at the 
 surface, and its consequent descent to the bottom 
 at a time when the bottom layer of water and in- 
 fraposed mud are at a temperature of at least 
 40 Fahr., may cause the finer particles of sediment 
 to rise throughout the pond and produce the ap- 
 pearance of milkiness. 
 
13 
 
 12 
 
 = 46 
 
 10 
 
 8 
 
 45 
 
 7 
 
 5 
 
 44 
 
 5 
 
 3 
 
 43 
 
 3 
 
 2 
 
 42 
 
 1 
 
 1 
 
 41 
 
 1 
 
 * 
 
 40 
 
 
 
 
 
 = 39 
 
 60 On Stocking. 
 
 The following considerations may be of use to 
 observers. Fresh water attains its greatest density 
 at 39 Fahr., and the difference from the greatest 
 density, expressed as unity, in hundred thousand 
 parts is 
 
 Density : unity less 
 
 Degrees Fahr. hundred thousand parts. Degrees Fahr. 
 32 
 33 
 34 
 35 
 36 
 37 
 38 
 39 
 
 That is to say, the density of fresh water at 32 
 Fahr. is "99,987, at 39 Fahr. 1 '00,000, and at 46 
 Fahr. '99,988. 
 
 From this it appears that the density of water 
 somewhere between 32 Fahr. and 33 Fahr. is 
 precisely the same as the density of water at 46 
 Fahr. And fluids of the same density in the same 
 vessel must occupy the same horizontal layer. 
 Therefore, at the beginning of winter, when the 
 pond water is about 46 Fahr. at the bottom, the 
 first hard frost causes the top layer to descend 
 and mix at 32, or thereabouts, with the bottom 
 layer at 46, but the difference of temperature 
 must liberate the thermal units from the warmer 
 water to raise the colder to the resulting temper- 
 ature ; in other words, force is changed from latent 
 
On Stocking. 61 
 
 to active, and currents of varying temperatures 
 result, bearing the finer particles of sediment 
 through the whole pond and producing the milky 
 appearance ; and this continues morning frost after 
 morning frost, until the bottom layer attains the 
 temperature of the greatest density, viz., 39 Fahr. 
 after which no action is apparent, or, if any, the 
 ponds appear clearer after a frosty night than be- 
 fore. 
 
 In this suggestion I have assumed that no per- 
 ceptible effect takes place except after the first 
 sharp frosts that is, only when the surface layer 
 is so rapidly cooled that no great action takes 
 place in passing 39 Fahr. The temperature of 
 the greatest density would occur in the case of a 
 gradual cooling, when the bottom water would be 
 reduced to this temperature without any distri- 
 bution, and the colder but lighter water could not 
 pass through to stir the sediment. 
 
 I also assume that the top layer of water would 
 descend in semi-vertical currents through the in- 
 termediate layers. 
 
 The position of feeding trout in lakes, some- 
 times in mid- water and sometimes at the surface, 
 has possibly much to do with temperature currents, 
 more so than with the average temperature of the 
 layers of water through which, I suppose, these 
 currents to pass. With the variation that sea- 
 water attains its greatest density at a temperature 
 
62 On Stocking. 
 
 below 32 Fahr., this suggestion may also explain 
 the movement of herring shoals, and ultimately 
 furnish some guide to the depth nets should be 
 sunk for successful fishing. It may be advisable 
 to experiment to ascertain the laws and conditions 
 under which a rapidly cooled layer of salt water 
 could pass through the immediate infraposed 
 layers. 
 
 THE CULTIVATION OF WATER 
 
 A piece of water can be cultivated so as to yield 
 results which can only be compared to a market 
 garden or to a vineyard. 
 
 Probably the larger lakes will always in this 
 country be more valuable for sporting purposes 
 than as food producing waters ; as trout preserves, 
 than as trout farms. Their cultivation as pre- 
 serves will consist of careful and systematic 
 netting, to remove all trout destroyers, such as 
 pike, perch, and above all, old large-headed, lanky- 
 bodied, barren trout ; of the introduction of fresh 
 blood when desirable ; and of stocking with such 
 discretion that the average size of the trout 
 caught with the rod be not below the desired 
 minimum. 
 
 The introduction of water-plants and of natural . 
 foods, for even the May fly may be successfully 
 transplanted while in the caddis state, and 
 in some cases the planting of timber, to shelter 
 
On Stocking. 63 
 
 exposed parts of the lake margins, also form part 
 of the cultivation of lakes as trout preserves. 
 
 I may now add a few words on their cultiva- 
 tion as trout farms : here the object is to 
 market the greatest weight of pink-fleshed trout, 
 and size is of slight importance, in fact, in 
 many places half-pound and pound trout com- 
 mand as good a price per pound as larger fish. 
 
 In cultivating for the market, it will, in most 
 instances, pay to net out all trout over two pound 
 weight, to reduce the loss from cannibalism, and 
 as the netting for the market requires to be con- 
 stant, the shotts for the net must be kept clear 
 from water plants, which require to be introduced 
 with more caution than when the lake is used for 
 sport, and only netted in winter and spring to 
 keep down vermin. 
 
 In cultivation for the market, gammarus and 
 Limncea peregra are valuable flesh-colourers, the 
 former especially giving a deep pink to the flesh 
 of the trout. I have found swan mussels l useful 
 in increasing gammarus, but whether from the 
 shelter their dead shells afford, or whether they 
 are eaten by gammarus, who is a great scavenger, 
 I cannot say. 
 
 As yet we are only on border-land of water 
 cultivation ; the subject is well worthy of study 
 and promises to repay manyfold any labour that 
 may be expended upon it. 
 
 1 Anodonta cygnea. 
 
64 On Stocking. 
 
 The cultivation of rivers consists in securing a 
 natural flow at all times throughout the river ; 
 but unfortunately this is precisely what cannot 
 be done. If compensation water be honestly 
 passed down, weirs and mill dams pierced with 
 passes, pollution stopped and weed cutting re- 
 gulated, much towards improving the river fishing 
 for Salmonidse will have been accomplished. 
 Many persons think that a portion of a stream 
 has only to be fenced off at either end and it can 
 be readily cultivated and safely stocked ; but the 
 difficulty of making a dam water-tight and a 
 screen trout-proof is great. Any little fall may 
 be utilised to prevent trout ascending, but as yet 
 it passeth the wit of man to prevent their de- 
 scending out of a stream. The difficulty is due to 
 flood, leaves, and frost ; it may be mitigated, but 
 cannot be entirely obviated. The safest plan is 
 to form a long level overflow the height of the 
 outlet screen, so that, when the latter clogs up, the 
 depth of the water on the overflow may be less 
 than one-inch ; trout will not readily pass a knife- 
 edge overflow under these circumstances. 
 
 TRANSPORT OF TEOUT. 
 
 The colder the weather the better for transport- 
 ing yearlings and two-year-olds, the cooler the 
 weather the better for fry ; in other words, in the 
 
On Stocking. 65 
 
 hardest frost two-year-olds may be sent to any 
 distance in Scotland, England, or Wales, not only 
 without loss on the journey, but without any loss 
 after transplantation ; we always prefer to break 
 the ice for two-year-olds. With yearlings it is 
 different, to this extent that yearlings travel 
 better by day than by night in very cold weather, 
 when, and only when, their is a long wait at any 
 point en route, in all other cases they, like two- 
 year-olds, travel best at night. . . . Fry cannot 
 stand frost at all, nor do they care for ice in the 
 travelling tank, we therefore like to send them so 
 as to arrive early in the morning in April or up to 
 the middle of May, when the weather is cool in 
 distinction to frosty . . . with a little attention 
 to the above points trout of all sizes can be safely 
 transported. 
 
 In conclusion, we recommend that all large 
 pieces of water should be examined and reported 
 on before being stocked, so that not only the best 
 strain of trout may be selected, but that the mode 
 of stocking may be varied to suite the circum- 
 stances of each particular case. I have appended 
 a draft report to show the questions requiring to 
 be dealt with, and the considerations which arise 
 in the case of a typical Lowland Lake. 
 
APPENDIX. 
 
 4tJt January 1892. 
 
 DEAR SIR, I have yours of 29th ultimo, and enclose 
 a Preliminary Eeport on the Lake of ... Time 
 has not permitted of my personally visiting the Lake, 
 but this is of the less importance, since a full report 
 necessitates the investigation and tabulation of the 
 Mollusca and Crustacea, more especially the Daphniadee 
 Copepoda, and Ostracoda, one species of which, Gandona 
 Candida, forms a large portion of the natural feeding at 
 Howietoun. 
 
 This investigation can only be carried on by boat and 
 in summer, and by the frequency of the various forms 
 of Mollusca and Crustacea, the gross weight of trout the 
 lake can carry is controlled. I must therefore omit the 
 Invertebrate Fauna, and the flora on which the fauna 
 largely depends, from this Preliminary Eeport, and deal 
 with the mode of stocking and question of cost in a 
 general manner, leaving any final recommendations till 
 the completion of the report. Yours sincerely, 
 
 J. -E. G. MAITLAND. 
 
6 7 
 
 PRELIMINARY REPORT 
 
 ON THE 
 
 LAKE OF .... AS AN ANGLING 
 LOCH FOE TROUT. 
 
 THE season being unsuitable for a proper investigation 
 into the food-bearing capacity of the Lake of . . ., 
 I have prepared this interim report from my general 
 personal knowledge of the district. I feel no doubt that 
 the Lake of ... is capable of being converted into 
 a first-class sporting trout loch ; but at present I am 
 unable to state approximate cost. I append, however, 
 certain calculations which will serve as a guide to the 
 Meeting. 
 
 GENERAL CONSIDERATIONS. 
 
 Pike and perch are plentiful, and the pike at least 
 will require thinning. Yearling Loch Leven trout will 
 hold their own against perch smaller burn trout will 
 not it is merely a question of the size of the "yearling." 
 
 PIKE. 
 
 The modes of thinning down pike are so well-known 
 that I need not enter into the matter here, further than 
 to remind the Meeting that reducing the number of pike 
 is more easily accomplished before spawning, which is 
 from March to May in this district, and that netting 
 
68 On Stocking. 
 
 should be commenced in February. If it is desired I 
 will be happy to enter fully into the subject in the final 
 report. 
 
 PERCH. 
 
 Perch destroy small yearlings ; large yearlings of four 
 inches and upwards are comparatively safe. The size of 
 the yearling (other things equal), depends on the size of 
 the parent egg. This again depends on the kind, size, 
 age, and nutrition of the spawner. The best S. Leven- 
 ensis eggs at Howietoun count 25,000 to the gallon, 
 while at Loch Leven the average is about 35,000. Small 
 hill burn trout eggs count 50,000 to the gallon, but by 
 selection and careful treatment, the size can be raised to 
 40,000 eggs to the gallon. From these figures it is 
 evident how far careful selection has removed S. Leven- 
 ensis at Howietoun, from Loch Leven trout. If, however, 
 a smaller breed of trout is desired to hold their own 
 against perch the young trout must be retained two 
 season's instead of eight months in the rearing ponds, 
 this multiplies the cost per hundred or per thousand 
 two-and-a-half times. 
 
 NATUKAL FEEDING IN LOCH. 
 
 The trout at present rise very badly, from which I 
 suspect the bottom feeding is good. If this be so (and 
 it is only by a careful examination in summer that 
 amount of bottom feeding can be estimated), the trout 
 will rise freely so soon as the stock of trout is increased 
 slightly out of proportion to the bottom feeding. If the 
 stock is still further increased, both the rate of growth 
 and the average weight of the trout will dimmish. The 
 prudent rate for stocking a piece of water in this part of 
 Scotland, under 300 feet above the sea, is 150 trout 
 
Appendix. 69 
 
 (yearling) per acre of less than 12 feet depth. When 
 the water is over 12 feet, the bottom feeding rapidly 
 decreases in quantity. When the feeding is very good 
 the number of yearling per acre of water of 12 feet or 
 less, may rise to, but never exceeds 200. But when the 
 water is more than 300 feet above sea level, or when the 
 bottom feeding is poor, the number falls to 100 or even 
 fewer yearlings per acre, the depth of which does not 
 exceed 12 feet. If the stock is too light there is little 
 sport, the fish grow larger and rapidly, but do not rise 
 freely. If the water is over stocked, there is again little 
 sport although the fish rise freely and are numerous, 
 since they remain so small as not to be worth fishing. 
 
 MODE OF STOCKING. 
 
 There are four modes of stocking, viz. : 
 
 By Redds. 
 
 When there are many small gravelly streams affording 
 altogether a large acreage of feeding streams suitable for 
 fry this is the most economical mode of stocking, but is 
 not suited to the Lake of . . ., the spawning streams 
 being naturally insufficient for the acreage of the lake. 
 
 By Fry. 
 This for the above reason is inadvisable. 
 
 By Yearlings. 
 
 Yearlings being placed directly into the loch, and being 
 reasonable in first cost are recommended for the Lake of 
 The only objection is that some loss must 
 occur in after years from cannibalism. 
 
 By-two-year-olds. 
 
 This is the usual mode of stocking, where old trout or 
 coarse fish already exist. It is gaining in favour every 
 season, and for moderate sized pieces of water where 
 
7O On Stocking. 
 
 nearly every fish comes to the rod, the cost of stocking 
 is fairly balanced by the dead value of the trout caught ; 
 but I am afraid in so large a piece of water as the Lake 
 of . . ., the cost of annual stocking with two-year- 
 olds would be out of proportion to the result. It might, 
 however, be the most convenient for the first year. 
 
 NUMBER OF TROUT REQUIRED YEARLINGS USED. 
 
 I have not the acreage of the Lake of . . ., but I 
 suppose there is about 500 acres of fishable water, and 
 about 200 acres either too shallow or too deep. On the 
 above supposition, at a moderate stocking of 100 year- 
 lings to the acre, 50,000 yearlings would be required. 
 These trout, three years after, should yield an average of 
 between 9 Ibs. and 10 Ibs. per acre (which is of 12 feet or 
 less in depth). 5000 Ibs. annually is the gross weight of 
 trout that should reasonably be expected to the rod. That 
 is/with 50,000 yearlings as a stocking in 500 acres of fishing 
 water (there being no pike supposed for purposes of this 
 calculation), it would be reasonable to expect 20,000 Ib. 
 trout caught in the second season, 10,000 J Ib. trout in the 
 third season, and 5000 1 Ib. trout in the fourth season, 
 leaving 15,000 trout for casualties and to grow to larger 
 fish. The question is, what annual stock of yearlings is 
 equivalent to a single stocking of 50,000 ? The number 
 varies in different waters, the cause being due to cannibal- 
 ism. If all the trout could be caught or removed in the end 
 of the fourth season, the second stocking with 50,000 year- 
 lings would be in 1896, which gives the annual average 
 required of 12,500, but owing to the cannibalistic pro- 
 pensities of trout, the annual number required is at 
 least 20,000 (in place of 12,500). And this I believe 
 to be the lowest annual stocking of yearlings the loch will 
 require. Should the feeding turn out as good as I anti- 
 cipate, a much larger number up to 40,000 yearlings 
 per annum might be used with economy and success ; 
 
Appendix. 7 1 
 
 but the number, whatever it is, should be adjusted so as 
 to secure a minimum average of 1 Ib. per trout caught 
 with the rod. 
 
 NUMBER REQUIRED TWO-YEAR-OLDS USED. 
 
 The number required for a single stocking of two-year- 
 olds (under the suppositions above) does not materially 
 differ from the number of yearlings, viz. : 50,000 for 500 
 acres of 12 feet depth and under as the loss at Howie- 
 toun between year- olds and two-year-olds for the year is 
 under 5 per cent. "But when the case of annual stocking 
 is considered, \ of 50,000 or 12,500 per annum is nearly 
 equivalent, as although single stocking with two-year- 
 olds requires to be triennial, and it would give 16,500 
 approximately, yet the 15,000 allowed for casualties with 
 yearlings is not required, and thus restores the balance. 
 However, if the two-year-olds are retained as T Ib. trout, 
 that is, when caught the same season they are placed in 
 the loch, some addition must be made to the annual 
 stocking. 
 
 COST OF STOCKING OVA IN REDDS. 
 
 The redds being mere ditches communicating with the 
 natural stream, are not in themselves expensive. In 
 favourable situations two men can cut a redd sufficient for 
 20,000 eggs in two days, and the first cost of 20,000 eggs 
 is about 7, 10s. But the two burns running in to the 
 Lake of ... are not capable of rearing sufficient 
 fry to keep up a fair stock of trout. Therefore, though 
 two or three redds might be made advantageously, they 
 would only provide a small supplementary stocking. 
 
 COST OF STOCK FRY. 
 
 Fry cost about 75 delivered per 100,000, but have no 
 advantage over a corresponding amount of ova in redds 
 100,000 three-month-old fry is practically the produce of 
 
72 On Stocking'. 
 
 150,000 eggs. The principal mortality being in the first 
 month after commencing feeding. 
 
 COST OF STOCKING YEARLINGS. 
 
 Yearlings (in this particular case) would cost about 
 11 per 1000 delivered. This, for an annual stocking of 
 20,000 yearlings would entail an expenditure of 220. 
 
 COST OF STOCKING TWO-YEAR-OLDS. 
 
 Two-year-olds would (in this particular case) cost 
 delivered, something under 30 per thousand, which for 
 15,000 two-year-olds would entail about 450 per annum. 
 
 COST OF STOCKING BY MEANS OF REARING PONDS. 
 
 I have no doubt that this is the proper course to adopt, 
 and may be considered under three sub-heads, viz. : (a) 
 Cost of construction ; (b) Cost of fry; (c) Cost of manage- 
 ment, food, risk, etc. 
 
 (a) COST OF CONSTRUCTION. 
 
 The ponds for rearing yearlings require to be about 
 100 feet long, 22 to 25 feet wide, and must be G feet in 
 the centre, with an iron drain-pipe and wooden valve to 
 draw off the pond which must be dry for at least three 
 weeks every year. The quantity of water required is one 
 6-inch pipe with a pressure of three diameters or 18 inches. 
 Experience has shown that the inlets and outlets should 
 be built, and that brick- work is preferable to masonry. 
 The cost of each pond is about 120, exclusive of water 
 supply and water course. The capacity of each pond is 
 from 8000 to 10,000 good yearlings and about 2000 small 
 yearlings annually. 
 
 (&) COST OF FRY. 
 
 The equivalent in fry is difficult to calculate, as so 
 much depends on the occidentation of the pond, the 
 quality of the water, and the skill of the attendant. At 
 
Appendix. 7 3 
 
 Howietoun we use six boxes, or 30,000 fry (nominal) to 
 stock each pond. The loss is almost entirely due to 
 cannibalism, which in a rearing pond is more prevalent 
 than in aji open stream. After the yearlings are caught 
 and sized there is no further loss. Six boxes of fry 
 would cost 30. 
 
 (c) COST OF MANAGEMENT, FOOD, ETC. 
 
 Each pond would require between stocking in May or 
 June and emptying in April, 15 cwt. of horse flesh and 
 about 1 cwt. of liver on first stocking. Horse flesh can be 
 bought in Glasgow, 
 
 15 cwt. would cost about . 300 
 
 And 1 cwt. liver about 100 
 
 In all 4 
 
 Say 4 per pond per annum. There is still to add 
 the proportion of the attendant's time about 2 hours per 
 day per pond say 12 per annum. Until the attendant 
 was trained, it would not be reasonable to expect more 
 than 7000 yearlings per pond. Thus three ponds would 
 be required to ensure 20,000 yearlings. 
 
 COST OF STOCKING BY MEANS OF REARING PONDS 
 CAPITULATION. 
 
 Three ponds at 120, 360 ; add inlet and outlet 
 
 works and inlet pipe, say 40, in all 400 ; and allow 
 
 interest and up-keep at 3 per cent., repairs 9J per cent. = 
 
 12 J per cent, on 400, . . 50 
 
 Food, three ponds at 4, . 12 
 
 Attendance, 6 hours per day, . 36 
 
 Cost of ponds per annum, . 98 
 
 And 18 boxes of fry at 5, . 90 
 
 188 
 
74 On Stocking. 
 
 as against 220 for 22,000 yearlings the difference is 
 . perhaps hardly worth the risk but with a good man 
 30,000 yearlings might be reasonably produced, and the 
 surplus either sold to reduce the cost, or if the bottom 
 feeding turns out as I expect, then 30,000 yearlings would 
 by no means be an excessive stocking. 
 
 I have not suggested a hatching house, because all 
 experience is against small hatcheries, they are in the end 
 more expensive than buying from larger establishments, 
 and the first structural cost is very heavy, if good in- 
 cubation is to be obtained. The principal hatching-house 
 at Howietoun cost, fitted, over 3000. Nor have I sug- 
 gested two-year-old ponds, as the depth and size, from 10 
 to 12 feet deep, and for 12,500 two-year-olds an area of 
 that depth of half an acre, makes these ponds very costly, 
 especially as if the two-year-olds are to thrive the pond 
 must be deepest and drained from the centre ; if any 
 other form of pond is used, it must either be larger in 
 extent, or much more lightly stocked. 
 
 BREED OF TROUT. 
 
 All the Scotch trout with two exceptions (Islay and 
 Orkney), pass from one form to another so as to render, 
 after a few generations, identification very difficult. I 
 therefore lay more stress on the selection of breeders than 
 on the original strain. But for the Lake of . . ., 
 the Loch Leven strain is, I believe, the best. Those 
 which have been bred at Howietoun since 1874 from the 
 best yearlings the produce of the largest breeders are 
 more stable in their characteristics than trout bred chiefly 
 from Loch Leven, where promiscuous breeding is tend- 
 ing to slightly lower the average weight, while a little 
 skill would in a few years very materially increase it. 
 
 In closing this preliminary report, I have to impress 
 the importance of first killing down the pike before they 
 spawn in March. Should rearing ponds be determined 
 
Appendix. . 7 5 
 
 on, they should commence early in summer. I do not 
 recommend a heavy stocking with yearlings before the 
 pike are reduced. In future years the trout will to some 
 extent keep down the young pike, and the net should be 
 able to do the rest. All large trout netted should be 
 killed until the stock of trout is good. 
 
 If rearing ponds are made, it will be necessary to em- 
 ploy an engineer, and most of the work should be done 
 by days' labour; of course the supply and waste-water 
 courses can be contracted for, but the cutting the ponds, 
 banking, inlet, outlet, and iron piping are not capable 
 of being contracted for. Yours truly, 
 
 J. K. G. MAITLAND. 
 
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