The date when the first of the eggs deposited was observed to be hatched was on the 31st of March, a period of more than four months after the stocking of the boxes; and during April and May most of the eggs had started into life, and the fry were observed waddling about the breeding-boxes, and were in June promoted to a place in the reception-pond, being then tiny fish a little more than an inch long. Sir William Jardine, who has taken a warm interest in the Stormontfield operations, thought that the first year’s experiments were remarkably successful in showing the practicability of hatching, rearing, and maintaining in health, a very large number of young fish, at a comparatively trifling cost. The artificial breeding of salmon is still carried on at these ponds, and with very great success, when their limited extent is taken into account. They have sensibly increased the stock of fish in the Tay, and also, as I will by and by relate, under the separate head of “The Salmon,” contributed greatly to the solution of the various mysteries connected with the growth of that fish. The fish, it is remarkable, suffer no deterioration of any kind by being bred in the ponds, and can compare in every respect with those bred in the river.

DESIGN FOR A SERIES OF SALMON-BREEDING PONDS.

Source of supply at top. Breeding-boxes next. Parr-pond after. Smolt-pond to the right. Adult salmon pond to the left. River at foot of plan. Ornamental walks. Clumps of trees, etc., according to taste.

The plan of the ponds at Stormontfield, as originally constructed, will be a better guide to persons desiring information than any written description. The engraving, with the double pond, shows a design of my own, founded on the Stormontfield suite it contains a separate pond for the detention, for a time, of such large fish as may be taken with their spawn not fully matured. Cottages for the superintendent of the ponds and his assistants are also shown in the plan.

The ponds at Stormontfield were originally designed with a view to breed 300,000 fish per annum, but after a trial of two years it was found, from a speciality in the natural history of the salmon elsewhere alluded to, that only half that number of fish could be bred in each year. Hence the necessity for the recently-constructed smolt-pond, which will now admit of a hatching at Stormontfield of at least 350,000 eggs every year. An additional reason for the construction of the new pond was the fact of the old one being too small in proportion to the breeding-boxes. Its dimensions were 223 feet by 112 feet at its longest and broadest parts. The new pond is nearly an acre in extent, and is well adapted for the reception of the young fish.

The egg-boxes at Stormontfield, unlike those at Huningue, are in the open air, and in consequence the eggs are exposed to the natural temperature, and take, on an average of the seasons, about 120 days to ripen into fish. For instance, the eggs laid down in November 1863 had not come to life at the time of my visit to the ponds in the second week of March 1864. The young fish, as soon as they are able to eat—which is not for a good few days, as the umbilical bag supplies all the food that is required for a time by the newly-hatched animal—are fed with particles of boiled liver. On the occasion of my last visit (December 22, 1864), Mr. Marshall threw a few crumbs into the pond, which caused an immediate rising of the fry at that spot in great numbers. It would, of course, have been a simple plan to turn each year’s fish out of the ponds into the river as they were hatched, but it was thought advisable rather to detain them till they were seized with the migratory instinct and assumed the scales of smolthood, which occurs, as already stated in other parts of this work, at the age of one and two years respectively. Indeed, the experiments conducted at the Stormontfield ponds have conclusively settled the long-fought battle of the parr, and proved indisputably that the parr is the young of the salmon, that it becomes transformed to a smolt, grows into a grilse, and ultimately attains the honour of full-grown salmonhood.

The anomaly in the growth of the parr was also attempted to be solved at Stormontfield, but without success. In November and December 1857 provision was made for hatching in separate compartments the artificially-impregnated ova of—1, parr and salmon; 2, grilse and salmon; 3, grilse pure; 4, salmon pure. It was found, when the young of these different matches came to be examined early in April 1859, that the sizes of each kind varied a little, Mr. Buist, the superintendent of fisheries, informing us that—“1st, the produce of the salmon with salmon are 4 in. in length; 2d, grilse with salmon, 3½ in.; 3d, grilse with grilse, 3½ in.; 4th, parr with grilse, 3 in.; 5th, smolt from large pond, 5 in.” These results of a varied manipulation never got a fair chance of being of use as a proof in the disputation; for, owing to the limited extent of the ponds at the time, the experiments had to be matured in such small boxes or ponds as evidently tended to stunt the growth of the fish. Up to the present time the riddle which has so long puzzled our naturalists in connection with the growth of the salmon has not been solved. A visitor whom I met at the ponds was of opinion that a sufficient quantity of milt was not used in the fructification of the eggs, as the male fish were scarcer than the female ones, and that those eggs which first came into contact with the milt produced the stronger fish.